U.S. patent application number 09/147104 was filed with the patent office on 2002-02-21 for an organic electroluminescent display device capable of preventing color mixing.
Invention is credited to EIDA, MITSURU, HOSOKAWA, CHISIO, MATSUURA, MASAHIDE.
Application Number | 20020021087 09/147104 |
Document ID | / |
Family ID | 12408644 |
Filed Date | 2002-02-21 |
United States Patent
Application |
20020021087 |
Kind Code |
A1 |
EIDA, MITSURU ; et
al. |
February 21, 2002 |
AN ORGANIC ELECTROLUMINESCENT DISPLAY DEVICE CAPABLE OF PREVENTING
COLOR MIXING
Abstract
An organic electroluminescence display device 100 comprises a
color modulating member 2 including a plurality of shading layers
21 and a plurality of color modulating layers 22, the layers 21 and
22 being arranged in a planar and discrete manner, an organic EL
electroluminescent member 3 including a plurality of organic EL
elements arranged in a planar and discrete manner at a site
corresponding to the color modulating layers 22, and a transparent
medium 1 sandwiched between the color modulating member 2 and the
organic EL electroluminescent member 3, wherein the relation
d2.gtoreq.d1 is satisfied, with d1 being a distance between the
color modulating member 2 and the organic EL electroluminescent
member 3, and d2 being a width of the shading layer. A practical
organic EL display device is thus provided which has an excellent
viewing angle property as well as an excellent visuality and which
can prevent occurrence of color-shift (color mixing) and blot.
Inventors: |
EIDA, MITSURU; (CHIBA-KEN,
JP) ; HOSOKAWA, CHISIO; (CHIBA-KEN, JP) ;
MATSUURA, MASAHIDE; (CHIBA-KEN, JP) |
Correspondence
Address: |
OBLON SPIVAK MCCLELLAND
MAIER & NEUSTADT
1755 JEFFERSON DAVIS HIGHWAY
FOURTH FLOOR
ARLINGTON
VA
22202
|
Family ID: |
12408644 |
Appl. No.: |
09/147104 |
Filed: |
October 5, 1998 |
PCT Filed: |
February 4, 1998 |
PCT NO: |
PCT/JP98/00467 |
Current U.S.
Class: |
313/504 |
Current CPC
Class: |
H05B 33/22 20130101;
H05B 33/12 20130101; H01L 27/322 20130101 |
Class at
Publication: |
313/504 |
International
Class: |
H01J 001/62 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 4, 1997 |
JP |
9-034240 |
Claims
What is claimed is:
1. An organic electroluminescence display device comprising a color
modulating member including a shading layer and a color modulating
layer, an organic EL electroluminescent member including an organic
electroluminescence element, and a transparent medium sandwiched
between said color modulating member and said organic EL
electroluminescent member, wherein the relation d2.gtoreq.d1 is
satisfied, with d1 being a distance between said color modulating
member and said organic EL electroluminescent member, and d2 being
a width of said shading layer.
2. The organic electroluminescence display device according to
claim 1, wherein said color modulating member comprises different
types of color modulating layers.
3. The organic electroluminescence display device according to
claim 1, wherein said color modulating member comprises the same
type of color modulating layers.
4. The organic electroluminescence display device according to
claim 1, wherein the relation T1.gtoreq.T2 is satisfied, with T1
being a thickness of said shading layer, and T2 being a thickness
of said color modulating layer.
5. The organic electroluminescence display device according to
claim 1, wherein the absolute value .vertline.T1-T2.vertline. is
2.0 .mu.m or less, with T1 being a thickness of said shading layer,
and T2 being a thickness of said color modulating layer.
6. The organic electroluminescence display device according to
claim 1, wherein the relation S1.ltoreq.S2 is satisfied, with S1
being the area of a luminescent region of said organic
electroluminescence element, S2 being the area of said color
modulating layer.
7. The organic electroluminescence display device according to
claim 1, wherein said color modulating layer comprises a
fluorescent layer.
8. The organic electroluminescence display device according to
claim 1, wherein the thickness of said color modulating layer is 5
.mu.m or more.
9. The organic electroluminescence display device according to
claim 1, wherein the absolute value .vertline.n1-n2.vertline. is
less than 0.4, with n1 being a refractive index of said color
modulating layer, and n2 being a refractive index of said
transparent medium.
10. The organic electroluminescence display device according to
claim 1, wherein the width of said shading layer becomes gradually
or stepwise small from said transparent medium side toward the
opposite side.
11. The organic electroluminescence display device according to
claim 1, wherein the transmittance of light in a visible region at
400-700 nm in wavelength of said shading layer is 10% or less.
12. The organic electroluminescence display device according to
claim 1, wherein the reflectivity of light in a visible region at
400-700 nm in wavelength of said shading layer is 10% or more.
Description
TECHNICAL FIELD
[0001] The present invention relates to an organic
electroluminescence display device (hereinafter, abbreviated simply
as "organic EL display device"). More particularly, the invention
relates to an organic EL display device that is suitably used, as a
display, a light source for the printer-head, or the like, for the
civil and industry uses.
BACKGROUND ART
[0002] As generally called a "man-machine interface", an electric
display device is an electronic device for visually transmitting
various information from various machines to a man and has an
important role as an interface to connect a man with a machine.
[0003] As the electric device, an active type(light-emitting type)
and a passive type (light-accepting type) are known. The active
type includes CRT (Cathode Ray Tube), PDP (Plasma Display Panel),
ELD (Electroluminescence Display/EL Display Device), VFD (Vacuum
Fluorescent Display), LED (Light-emitting Diode), or the like. On
the other hand, the passive type includes LCD (Liquid Crystal
Display), ECD (Electrochemical Display), EPID (Electro Phoretic
Image Display), SPD (Suspended Particle Display), TBD (Twisting
Ball Display), PLZT (Transparent Ceramic display using the strong
dielectric PLZT [(Pb, La)(Zr, Ti)O.sub.3]), or the like.
[0004] The EL display device (ELD) or an EL element, which
constructs the ELD, has a high visuality because of the
self-emission, and the high durability against the shock because
they are completely solid. Therefore, the development of various EL
display devices is in progress now, in which inorganic and organic
compounds are used in emitting layers. Among them, an organic EL
display device, wherein an organic compound is sandwiched between
two electrodes, is strongly expected as a display that can very
efficiently and very brightly emit light of various kinds of colors
because of the variety of organic compound.
[0005] Therefore, methods for constructing a full-color organic
display device have been keenly developed. For example, Japanese
Patent Laid-open Publication No. Hei8-264828 discloses a method to
emit each of different colors (e.g. three primary colors of red,
blue, and green) by plane and discretely placing the emitting parts
of the organic EL display device.
[0006] There were problems, however, that it is necessary to newly
develop emitting materials for each color to plane and discretely
place emitting parts of the organic EL display element, and to
display by emitting light of different colors, and that it has a
low durability to a process (e.g. photolithography), in which it is
plane and discretely placed, because the material per se is an
organic compound.
[0007] Therefore, a method to decompose or modulate monochrome
light through a color modulating layer (e.g. a color filter or a
fluorescent layer) has been proposed(Japanese Patent Laid-open
Publication No. Hei3-152897). This method is excellent in the point
that it can be simply constructed because providing only a single
color as an emitting layer is enough.
[0008] There are, however, some gaps between an organic EL element
and a color modulating layer or between color modulating layers
because it is necessary to provide a color modulating layer in
addition to the organic EL element. Therefore, from these gaps
light from the organic EL element or light from the
light-modulating layer leak, and the viewing angle became narrow
(i.e. color shift), giving an organic EL display device with a low
visuality.
[0009] Thus, Japanese Patent Laid-open Publication No. Hei5-94878
discloses an EL display device in which a transparent resin layer
is provided between an EL element and a color filter, with the
thickness of the transparent resin layer being thinner than the
distance between pixels of the EL element (See FIG. 15).
[0010] The problem of viewing angle has not been adequately solved,
however, because there is no shading layer in such constitution,
and leak of light from the side surface of the color filter layer
can not be controlled. In addition, in case a fluorescent layer is
used instead of the color filter layer, the fluorescent
pigment(dye) more isotropically fluoresces, and as a result, leak
of light becomes large, and a visuality became inferior.
[0011] In Japanese Patent Laid-open Publication No. Hei5-258860, is
disclosed a multi-color luminescence device in which a fluorescent
medium is placed in such a way that luminescence of an organic EL
element can be received (See FIG. 16).
[0012] The problem of viewing angle has not been adequately solved,
however, because no shading layer between fluorescent media is
shown in such constitution.
[0013] In Japanese Patent Laid-open Publication No. Hei5-94879, is
disclosed an EL panel in which a spacer, which has a shading
property and nearly perpendicularly projects against the substrate
surface of the EL element, is provided, and a color filter is
placed oppositely (See FIG. 17).
[0014] Although there is no problem concerning viewing angle in
this case, the relation between the thickness of the shading layer
and that of the color modulating layer and the relation between the
distance from the organic EL element to the shading layer and the
width of the shading layer are not taken into account, therefore
such a problem occurred that an organic EL display device could not
be constructed practically.
[0015] In Japanese Patent Laid-open Publication No. Sho63-40888, is
disclosed a color display in which an EL element and a color filter
are placed oppositely (See FIG. 18). In such constitution, however,
the relation between the thickness of the shading layer and that of
the color modulating layer, and the relation between the distance
from the organic EL element to the shading layer and the width of
the shading layer, are not taken into account, therefore such a
problem occurred that a full-color EL display device could not be
constructed practically.
[0016] The present invention was conceived in view of the above
problems. It is therefore the object of the present invention to
provide a practical organic EL display device that is excellent in
a viewing angle property and a visuality, and allows a prevention
of occurrence of color shift (color-mixing).
DISCLOSURE OF THE INVENTION
[0017] In the organic EL display device according to the present
invention, a color modulating member composed of shading layers and
color modulating layers, and an organic EL luminescent member
composed of organic EL elements, are placed sandwiching a
transparent medium to achieve the above-mentioned purpose,
satisfying the relation d2.gtoreq.d1, with d1 being the distance
between the color modulating member and the organic EL luminescent
member; d2 being the width of the shading layer.
[0018] In case the organic EL display device is constructed
according to the present invention, it is preferred to construct
the color modulating member with different kinds of color
modulating layers.
[0019] In case the organic EL display device is constructed
according to the present invention, it is preferred to construct
the color modulating member with one kind of a color modulating
layer.
[0020] In case the organic EL display device is constructed
according to the present invention, it is preferred to satisfy the
relation T1.gtoreq.T2, with the thickness of the shading layer
being T1; that of the color modulating layer being T2.
[0021] In case the organic EL display device is constructed
according to the present invention, it is preferred to satisfy the
relation .vertline.T1-T2.vertline..ltoreq.2.0 .mu.m, with T1 being
the thickness of the shading layer; T2 being that of the color
modulating layer.
[0022] In case the organic EL display device is constructed
according to the present invention, it is preferred to satisfy the
relation S2.gtoreq.S1, with S1 being the area of the luminescent
region of the organic EL element; S2 being that of the color
modulating layer.
[0023] In case the organic EL display device is constructed
according to the present invention, it is preferred to construct
the color modulating layer from a fluorescent layer.
[0024] In case the organic EL display device is constructed
according to the present invention, it is preferred that the coat
thickness of the color modulating layer is equal to or thicker than
5 .mu.m.
[0025] In case the organic EL display device is constructed
according to the present invention, it is preferred to satisfy the
relation .vertline.n1-n2.vertline.<0.4, with n1 being the
refractive index of the color modulating layer; n2 being that of
the transparent medium.
[0026] In case the organic EL display device is constructed
according to the present invention, it is preferred to gradually or
stepwise reduce the width of the shading layer from the transparent
medium side to the opposite side.
[0027] In case the organic EL display device is constructed
according to the present invention, it is preferred that the
transmittance of light in the visible region of 400 nm to 700 nm of
the shading layer is 10% or less.
[0028] In case the organic EL display device is constructed
according to the present invention, it is preferred that the
reflectance of light in the visible region of 400 nm to 700 nm of
the shading layer is 10% or more.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 illustrates an embodiment of an organic EL display
device of the present invention, in which (a) is a sectional view,
and (b) and (c) are perspective views respectively.
[0030] FIG. 2 is a sectional view for explaining a supporting
substrate used in the present invention, in which (a) and (b) show
the case where a transparent supporting substrate is used; and (c)
shows the case where it is not necessary to use a transparent
one.
[0031] FIG. 3 is a sectional view for explaining the relation
between d1 and d2, wherein d1 is the distance between the organic
EL luminescent member and the color-modulating member; d2 the width
of the shading layer, in which (a) shows the case of d1>d2 and
(b) shows the case of d1.ltoreq.d2.
[0032] FIG. 4 is a sectional view for explaining the viewing angle
of the present invention.
[0033] FIG. 5 is a sectional view for explaining the relation
between the thickness of the shading layer T1 and that of the color
modulating layer T2, in which (a),(b) and (c) show the case of
T1<T2, and (d), (e) and (f) show the case of T1.gtoreq.T2.
[0034] FIG. 6 illustrates the relation S2.gtoreq.S1 of the present
invention.
[0035] FIG. 7 is a sectional view for explaining the relation
between the area of luminescent region of the organic EL element S1
and that of the color modulating layer S2, in which (a) shows the
case of S1>S2, and (b) shows the case of S1.ltoreq.S2.
[0036] FIG. 8 is a sectional view for explaining the color
modulating layer used in the present invention, in which (a) shows
the case where a color filter was used and (b) shows the case where
a fluorescent layer was used.
[0037] FIG. 9 is a sectional view for explaining the form of the
shading layer used in the present invention, in which (a) shows a
rectangular form, (b)shows an inverted trapezoidal form and (c)
shows a T-shaped form.
[0038] FIG. 10 is a sectional view schematically showing the
reflecting part of the shading layer in the side surface that
contacts with the color modulating layer, in which (a) shows the
case where there is no reflecting part, (b) shows the case where a
reflecting part was provided in a rectangular shading layer, and
(c) shows the case where a reflecting part was provided in a
inverted trapezoidal layer.
[0039] FIG. 11 is a diagram schematically showing the patterned
shading layer according to the present invention.
[0040] FIG. 12 is a diagram schematically showing a dot-pattern of
the stripe arrangement according to the present invention.
[0041] FIG. 13 is a diagram schematically showing the
stripe-pattern of the anode according to the present invention.
[0042] FIG. 14 is a diagram schematically showing the
stripe-pattern of the cathode according to the present
invention.
[0043] FIG. 15 is a sectional view showing the prior art, in which
a transparent layer is provided between an EL element and a color
filter.
[0044] FIG. 16 is a sectional view showing the prior art, in which
a luminescent medium is placed in order to receive luminescence of
an organic EL element.
[0045] FIG. 17 is a sectional view showing the prior art, in which
a spacer having a shading property is placed in gaps of pixels of
the EL element.
[0046] FIG. 18 is a sectional view showing the prior art, in which
an EL element and color filters are placed oppositely.
[0047] FIG. 19 is a diagram for explaining the influence of
roughness on the surface in a color modulating member (Part 1), in
which
[0048] (a) shows the case where the roughness of the surface in a
color modulating member is large and (b) shows the case where the
roughness on the surface in a color modulating member is small.
[0049] FIG. 20 is a diagram for explaining the influence of
roughness on the surface in a color modulating member (Part 2).
[0050] FIG. 21 is a diagram for explaining the case where a
transparent flattened layer is overlaid on a color-modulating
member.
BEST MODE FOR CARRYING OUT THE INVENTION
[0051] The best mode for carrying out the invention will now be
described specifically with reference to the accompanying
drawings.
[0052] 1. Constitution of Organic EL Display Device
[0053] As FIGS. 1a-1c show, the organic EL display device 100 is
constructed with a color modulating member 2 and an organic EL
luminescent member 3 sandwiching at least a transparent medium 1.
In the color modulating member 2, a plurality of shading layers 21
and a plurality of color modulating layers 22 are placed plane,
repeatedly, and discretely. In an organic EL luminescent member 3,
a plurality of organic EL elements are plane and discretely placed
in the position corresponding to the color modulating layer 22.
[0054] Accordingly, if each organic EL element 31 luminescens, the
light transmits the transparent medium 1, the light emitted from
the organic EL element 31 is decomposed or modulated through the
corresponding color modulating layer 22, and visualized as
luminescence whose color is different from the light from the
organic EL element 31.
[0055] Therefore, in case each the color modulating member 2 is
constructed with a different kind of color modulating layers 22 in
this way, multi-color display becomes possible in the organic EL
display device 100. Multi-color display can also be carried out by
transmitting the luminescence of the organic EL element 31 without
modulation by forming a part (transparent layer) in which a color
modulating layer is not provided in a part of the color modulating
member 2.
[0056] In case the color modulating member 2 is constructed with
the same kind of color modulating layers, monochrome display
becomes possible in the organic EL display device 100.
[0057] Next, the constitution including more concrete supporting
substrate in the organic EL display device 100 according to the
present invention will be described below. Practically, the organic
EL display device 100 requires a substrate to support itself.
[0058] Examples for it are shown in FIGS. 2a-2c. FIG. 2a
illustrates the case that the transparent medium 1 has another role
as a supporting substrate and constitutes a transparent supporting
substrate 41.
[0059] In FIG. 2b, a transparent supporting substrate 41 is placed
below the color modulating layers 22 and the shading layers 21.
[0060] In FIG. 2c, two supporting substrates are used; the first
supporting substrate 41 is placed below the color modulating layers
22 and the shading layers 21; the second supporting substrate 4 is
placed on an organic EL luminescent member 3 including the organic
EL element 31.
[0061] Next, the reasons why the relation between the distance (d1)
from a color modulating member 2 to an organic EL luminescent
member 3 and the width (d2) of a shading layer 21 must be
restricted in case multi-color or monochrome display is carried out
in the organic EL display device 100, i.e., the reasons why the
relation d2.gtoreq.d1 must be satisfied in the organic EL display
device 100 will be described below referring to FIGS. 3a and 3b,
wherein the distance (d1) from a color modulating member 2 to an
organic EL luminescent member 3 is defined as the shortest distance
between a shading layer 21 or a color modulating layer 22 of said
color modulating member 2 and a position corresponding to the
boundary to the transparent medium 1, and in case the position
corresponding to said boundary is defined, a shading layer 21
and/or a color modulating layer 22 are selected so that the
distance to an organic EL element is shortest, more strictly it is
expressed as a length (distance) of the perpendicular that is drawn
from the position corresponding to the boundary between a shading
layer 21 or a color modulating layer 22 and the transparent medium
1 to the position mainly corresponding to a luminescent part such
as a luminescent layer in an organic EL element. In FIGS. 3a and 3b
also, d1 is expressed as a distance of the perpendicular in this
way; d2 is expressed as a width of a shading layer 21 on the side
that contacts with the transparent medium 1; d2 is illustrated in
this way also in FIGS. 3a and 3b.
[0062] As the light emitted from an organic EL element 31 is
isotropically radiated, if the light is not absorbed in the
transparent medium 1, the intensity of the light is equally
distributed depending on the distance from said organic EL element
31. Therefore, as shown in FIG. 3a, a significant amount of light
is radiated not only to a color modulating layer 22a at the
position corresponding to the organic EL element 31 but also to the
adjacent color modulating layer 22b.
[0063] Therefore, as shown in FIG. 3a, in the case of d1>d2, the
angle (.theta..sub.1) of incidence of the light entered into the
color modulating layer 22b becomes large, and the intensity of the
light entered into the color modulating layer 22b becomes high. As
a result, the light having a color from an unintended color
modulating layer 22b is significantly mixed ("color-mixing") as
well as the light having a desired color obtained by decomposing or
modulating in a color modulating layer 22a, and the light
corresponding to a desired color might not be adequately
visualized. "Color-mixing" in the present invention is the case
that the X- and Y-shifts are larger than 0.02 against CIE
chromaticity coordinates of luminescent light from the intrinsic
color modulating layer.
[0064] Although in case the color modulating layers are of the same
kind, i.e., above-mentioned color modulating layer 22a and color
modulating layer 22b are the same kind, the color-mixing problem
does not occur even if d1>d2, the display becomes unclear and
fuzzy, and lacks clearness.
[0065] In contrast to it, as shown in FIG. 3b, in case the relation
d2.gtoreq.d1 is satisfied, the angle (.theta..sub.2) of incidence
of the light entered into the color modulating layer 22b becomes
small, and the intensity of the light entered into the color
modulating layer 22b becomes low. As a result, color-mixing is
reduced, and the light corresponding to desired light can be
visualized.
[0066] Thus, in case multi-color or monochrome display is carried
out in the organic EL display device 100 according to the present
invention, a practical organic EL display device with reduced color
shift (color-mixing) can be provided by reducing the light entered
into the adjacent color modulating layer 22b through a shading
layer on both sides of the color modulating layer 22a by satisfying
the relation d2.gtoreq.d1.
[0067] In addition, in case the color modulating layers are of the
same kind, reduction of clear display such as unclear and fuzzy
display can be prevented by satisfying such a relation.
[0068] Concerning the relation between d1 and d2, preferred (d2-d1)
value is 1-100 .mu.m. In case the (d2-d1) value is smaller than 1
.mu.m, unevenness of thickness of the transparent medium 1 could
generate a region that does not satisfy the relation d2.gtoreq.d1
partially. On the other hand, in case the (d2-d1) value is larger
than 100 .mu.m, the width of the shading layer 21 becomes large,
and could cause reduction of high fineness and clearness of
image.
[0069] Accordingly, the more preferred (d2-d1) value is within the
range of 5-50 .mu.m, and the most preferred (d2-d1) value is within
the range of 10-40 .mu.m.
[0070] In addition, it is preferred to satisfy the relation
T1.gtoreq.T2 in the organic EL display device according to the
present invention, with T1 being a thickness of a shading layer; T2
being a thickness of a color modulating layer. The reason for this
will be described below referring to FIGS. 4, 5a-5f.
[0071] In order to explain the reason why the relation T1
.gtoreq.T2 must be satisfied, the relation with the viewing angle
must be discussed. As shown in FIG. 4, said viewing angle is
defined as each angle where a desired color of the light changes in
case viewing angle is changed to the right and the left from the
site in front of the organic EL display device.
[0072] Therefore, as shown in FIG. 4, in case the desired color of
the light is changed at each angle shown with two inclined arrows
originating the organic EL element 31, the viewing angle is
expressed as a positive or negative angle value.
[0073] FIGS. 5a, 5b, and 5c show that the case the thickness T1 of
a shading layer 21 is smaller than the thickness T2 of a color
modulating layer 22a, i.e., T1<T2. On the other hand, FIGS. 5d,
5e, and 5f show that the case in which the thickness T1 of a
shading layer 21 is larger than the thickness T2 of a color
modulating layer 22a, i.e., T1>T2.
[0074] FIGS. 5a and 5d show the constitution in which the thickness
of a transparent medium 1 is uneven, and each bottom surface of a
shading layer 21 and a color modulating layer 22a (22b) having
different thickness are smooth.
[0075] FIGS. 5b and 5e show the constitution in which the thickness
of a transparent medium 1 is uniform, and a shading layer 21 and a
color modulating layer 22a (22b) having different thickness are
placed on the flat bottom surface of a transparent medium 1.
[0076] FIGS. 5c and 5f show the constitution in which the thickness
of a transparent medium 1 is uneven, and each bottom surface of a
shading layer 21 and a color modulating layer 22a (22b) having
different thickness are rugged.
[0077] As the light emitted from the organic EL element 31 radiates
isotropically (all azimuths) as shown in FIG. 5a, a part of the
light enters into the color modulating layer 22b with an angle. The
entrance of this part of the light is illustrated as an inclined
arrow originating from the organic EL element 31 to a color
modulating layer 22a (22b) in FIG. 5a.
[0078] In the constitution shown in FIG. 5a, as the thickness T1 of
a shading layer 21 is smaller than the thickness T2 of a color
modulating layer 22a, the light comes from the organic EL element
31 in an inclined direction might not be shaded adequately by a
shading layer 21.
[0079] Therefore, the unshaded light enters into a part of the
color modulating layer 22b adjacent, through a shading layer, to
the shading layer with an angle (.theta..sub.3).
[0080] As light enters into a color modulating layer 22b and light
of an undesired color is emitted outside, said light of the
undesired color and light of a desired color obtained from the
color modulating layer 22a tend to mix, change in color could be
observed in a very narrow angle, in case the angle to see the
organic EL display device is changed to the right or left. Briefly,
the viewing angle could become narrow, and this could cause
unfavorable state.
[0081] On the other hand, in the constitution shown in FIG. 5d, as
the thickness T1 of a shading layer 21 is larger than the thickness
T2 of the color modulating layer 22a, the light having an angle
(.theta..sub.3) to a color modulating layer 22b among the light
emitted from the organic EL element 31 is adequately shaded by a
shading layer 21 and might not enter into a color modulating layer
22b.
[0082] Therefore, it becomes rare to emit the light of undesired
colors in the color modulating layer 22b and to visualize the light
of unintended colors.
[0083] As it becomes rare to mix the light of undesired colors and
the light of unintended colors, it is possible to visualize the
light of desired colors in a wide range of angle. Briefly, a
favorable state with a wide range of viewing angle can be
achieved.
[0084] In the constitution shown in FIG. 5b, as the thickness T1 of
a shading layer 21 placed on the bottom surface of a transparent
medium 1 having a uniform thickness is smaller than the thickness
T2 of a color modulating layer 22a placed similarly, the light of
the color decomposed or modulated in the color modulating layer 22a
might not be adequately shaded with the shading layer 21.
[0085] Therefore, the unshaded light enters into a part of a color
modulating layer 22b adjacent to the color modulating layer 22a
with an angle. In FIG. 5b, the light that enters from a color
modulating layer 22a into a color modulating layer 22b is
illustrated as an inclined dotted arrow originating from the color
modulating layer 22a.
[0086] In case the shading layer 21 does not function adequately in
this way, the light of undesired colors obtained from the color
modulating layer 22a and the light of unintended colors from color
modulating layer 22b tend to mix, and a change in light in a very
narrow range of angle could be observed in case the angle in order
to see the organic EL element 31 is changed to the right or
left.
[0087] Briefly, an unfavorable state, in which the viewing angle
becomes narrow, could occur. Particularly in case a color
modulating layer 22 isotropically fluoresces as a fluorescent
layer, the viewing angle becomes narrow remarkably.
[0088] On the other hand, in the constitution shown in FIG. 5e, as
the thickness T1 of a shading layer 21 is larger than the thickness
T2 of a color modulating layer 22a, the light having an angle to
the color modulating layer 22b among the light of the color
decomposed or modulated in the color modulating layer 22a is
adequately shaded with the shading layer 21 and might not enter
into said color modulating layer 22b.
[0089] Therefore, it becomes rare to visualize light of an
unintended color. The light of a desired color can be visualized
with a wide range of angle by reducing mixing of the light of a
desired color and that light of an unintended color. Briefly, a
favorable state having a wide range of viewing angle can be
achieved.
[0090] In the constitution shown in FIG. 5c, the light that comes
in an inclined direction from the organic EL element 31 might not
be adequately shaded by the shading layer 21, and the light of the
color decomposed or modulated in a color modulating layer 22a might
not be adequately shaded by the shading layer 21, either.
[0091] Therefore, as explained above referring to FIGS. 5a and 5b,
the light of a desired color obtained from a color modulating layer
22a and the light of an undesired color tend to mix.
[0092] Thus, in case the angle to see the organic EL element 31 is
changed to the right or left, a change in light in a very narrow
range of angle could be visualized, the viewing angle would become
narrow, and these could cause an unfavorable state.
[0093] On the other hand, in the constitution shown in FIG. 5f, the
light that comes from the organic EL element 31 in an inclined
direction can be adequately shaded with a shading layer 21, and the
light having an angle to the color modulating layer 22b among the
light decomposed or modulated in a color modulating layer 22a can
also be adequately shaded with a shading layer 21.
[0094] Therefore, it becomes possible to visualize the light of a
desired color in a wide range of angle by reducing mixing of the
light of a desired color and the light of an unintended color.
Briefly, a favorable state in which the viewing angle is larger is
achieved.
[0095] In the organic EL display device 100 according to the
present invention, a preferred .vertline.T1-T2.vertline. value is
2.0 .mu.m or smaller, with T1 being the thickness of the shading
layer 21; T2 being the thickness of the color modulating layer 22,
both constituting a color-modulating member.
[0096] By constituting in this way, the roughness on the surface of
the color modulating member is smoothed (flattened), and it is
possible to reduce generation of defect or cross talk (luminescent
at sites other than the predetermined sites) by disconnection or
short circuit in the organic EL element 31.
[0097] Therefore, in the constitution shown in FIG. 2b in which a
color modulating member (shading layer 21 and color modulating
layer 22) is placed on a transparent supporting substrate 41, on
which the organic EL element 31 is formed through a transparent
medium 1, a desired value of .vertline.T1-T2.vertline. is equal to
or smaller than 2.0 .mu.m.
[0098] The reasons for constituting in this way will be explained
below referring to FIGS. 19a, 19b, and 20.
[0099] First, FIGS. 19a and 19b illustrate the case in which the
organic EL element 31 is contacted with each color modulating layer
22 of a color modulating member 2.
[0100] The organic EL element 31 is constructed in such a way that
an organic layer 34 (mainly emitting layer) is placed between two
electrodes 32 and 33, wherein said two electrodes 32 and 33 are
each stripe-form, and they intersect each other.
[0101] FIG. 19a illustrates the case in which roughness on the
surface of the color modulating member is large
(.vertline.T1-T2.vertline.>2.0 .mu.m). In this case, the
roughness on the surface gives warp to the organic EL element 31.
This could cause a leak current between the two electrodes 32 and
33 in the organic EL element 31, or defect or cross talk
particularly by disconnection of electrode 32 or the like, and
reduce the yield in production of the organic EL display
device.
[0102] On the other hand, FIG. 19b illustrates the case in which
roughness of the surface of the color modulating member is small
(.vertline.T1-T2.vertline.2.0 .mu.m). In this case, the roughness
of the surface would rarely give warp to the organic EL element 31
which is a thin coat.
[0103] This point will be explained in more detail, based on the
result shown in Table 1 below. Table 1 summarizes the results of
test concerning relation between the magnitude of the roughness of
the surface of the color modulating member 2 in FIGS. 19a and 19b,
i.e., .vertline.T1-T2.vertline. and generation of defect parts
(non-luminescent part) and cross talk.
[0104] Concretely, various color modulating member 2 were prepared
by dependently changing the thickness T1 of the shading layer 21
and the thickness T2 of the color modulating layer 22. The organic
EL display device was constructed as shown in FIG. 20 using these
color modulating member 2, and generation of defect and cross talk
were observed visually when said organic EL display device was
driven, wherein the frequency (frequent or rare) of defect and
cross talk in the organic EL display device was judged according to
the following criteria:
[0105] Rare: the generation of defect or cross talk were observed
in 30% area or less of the overall display area
[0106] Frequent: the generation of defect or cross talk were
observed in more than 30% area of the overall display area
[0107] As easily understood from Table 1, if the roughness of the
surface of the color-modulating member, i.e.,
.vertline.T1-T2.vertline. is equal to or smaller than 2.0 .mu.m,
frequency of defect and generation of cross talk can be reduced.
Therefore, it is considered that the magnitude of the roughness of
the surface of the color modulating member 2 influences the yield
of production of the organic EL display device.
1 TABLE 1 Frequency of Roughness of the Frequency of generation
surface defect of cross talk 0.2 Rare Rare 0.5 Rare Rare 1.0 Rare
Rare 2.0 Rare Rare 3.0 Frequent Frequent 4.0 Frequent Frequent 5.0
Frequent Frequent
[0108] As shown in FIG. 21, the roughness of the surface of the
color modulating member 2 can be reduced (flattened) by overlaying
a transparent flattened layer 5, i.e., a transparent medium 1 on a
color modulating member 2 shown in FIG. 19a. However, in case the
thickness of the transparent flattened layer 5 is too large, the
light might leak from the organic EL element (not shown), the color
shift (color-mixing) might occur, and the viewing angle might
become narrow. Therefore, it is preferred to select the thickness
of the transparent flattened layer 5, taking (1) reduction of
roughness on the surface of the color modulating member 2, (2)
color shift, and (3) balance into account although the thickness
depends on the fineness of the color modulating member 2 and the
luminescent member 3.
[0109] Then, the relation between the area (S1) of the luminescent
region of an organic EL element in the organic EL display device
100 according to the present invention and the area (S2) of the
region of the color modulating layer, will be explained below. As
mentioned above, it is preferred that the organic EL display device
satisfies the relation S2.gtoreq.S1. The region of the color
modulating layer becomes possible to practically cover the
luminescent region by satisfying such a relation concerning
area.
[0110] Concretely, it is preferred in the present invention to
adopt such constitution as shown in FIGS. 6a-6e. FIG. 6a
illustrates the case in which the area of region of the color
modulating layer 22 is same as the area of the luminescent region
of the organic EL element 31, i.e. S2=S1. The area of the region of
the color modulating layer 22 is shown with solid lines, and the
area of the luminescent region of the organic EL element 31 is
shown with dotted lines. Therefore, in the case of FIG. 6a, S2=S1,
the solid lines showing the color modulating layer 22 and the
dotted lines showing the luminescent region are superimposed.
[0111] FIGS. 6b-6e illustrates the case in which the area of region
of the color modulating layer 22 is larger than the area of the
luminescent region of the organic EL element 31, i.e., S2>S1,
and the former region includes the latter. Therefore, in these
cases, S2>S1, the dotted line showing the luminescent region is
shown inside the solid line showing the color modulating layer
22.
[0112] By constituting an organic EL display in such a way that
such relation concerning area is satisfied, the region of the color
modulating layer can easily cover the luminescent region, and can
easily prevent color-mixing and generation of light of an
unnecessary color.
[0113] The reasons why generation of unnecessary light can be
prevented by satisfying the relation S2.gtoreq.S1, will be
explained in more detail below referring to FIGS. 7a and 7b.
[0114] FIG. 7a illustrates a front view of a cross section of an
organic EL display in the case of S1>S2. As explained above, the
light emitted from the organic EL element 31 radiates isotropically
and becomes light having an isotropic intensity distribution.
Therefore, in the case of S1>S2 as shown in FIG. 7a, the light
could enter with a large angle of incidences .theta..sub.4 not only
into a color modulating layer 22a but also into the color
modulating layer 22b adjacent to it. As a result, the color is
visualized mixing, and it becomes relatively difficult to visualize
the light of a desired color.
[0115] In case the relation S2.gtoreq.S1 is satisfied as shown in
FIG. 7b, however, the angle of incidence .theta..sub.5 becomes
small, and the intensity of the light that enters into the color
modulating layer 22b becomes relatively small. As a result, mixing
of color is reduced, and it becomes possible to selectively
visualize the light of a desired color.
[0116] Therefore, in case multi-color and monochrome display is
carried out in the organic EL display device 100 according to the
present invention, a practical organic EL display device that
rarely generates color shift (color-mixing) can be provided by
satisfying the relation S2.gtoreq.S1.
[0117] 2. Each Component
[0118] (1) Color-modulating Layer
[0119] For the color modulating layer according to the present
invention, (1) a color filter 5 that decomposes or cuts the light
of the organic EL element 31 or (2) a fluorescent layer 6 that
modulates the light of the organic EL element 31 to fluorescence
with a different color (color with longer wavelength), can be used
as shown e.g. in FIGS. 8a and 8b.
[0120] In case a color filter 5 is used, the loss of light is
relatively high because it takes out light functionally by
decomposing or cutting. In case e.g. white luminescence is
decomposed into three primary colors (red, green, blue), brightness
of white color might be reduced to ca. 1/3.
[0121] On the other hand, in case a fluorescent layer 6 is used, it
has a function to modulate light into fluorescence having a longer
wavelength. If a fluorescent pigment absorbs at a yield of 80% and
it fluoresces at a fluorescent yield of 80%, as a result it can
modulate the light at a yield of 64%. Such fluorescent pigment is
practically known.
[0122] Therefore, it is more preferred to use a fluorescent layer 6
in the color modulating layer in the organic EL display device
according to the present invention. In addition, it is more
preferred to use a fluorescent layer 6 in order to enlarge the
viewing angle and to enhance the visual-check property as the
fluorescent layer 6 radiates per se isotropically.
[0123] 1) Color Filter
[0124] Materials for the color filters used for color modulating
layers will be explained below. Materials for said color filters
include e.g. the following pigments or a solid in which said
pigments are dissolved or dispersed in a binder resin.
[0125] Red (R) Pigments:
[0126] Perylene-based pigments, rake pigments, azo-based pigments,
quinacridone-based pigments, anthraquinone-based pigments,
anthracene-based pigments, isoindolin-based pigments,
iso-indolinone, or the like, and a mixture of two or more of these
pigments can be used.
[0127] Green (G) Pigments:
[0128] Polyhalogenated phthalocyanine-based pigments,
polyhalogenated copper phthalocyanine-based pigments,
triphenylmethane-based basic dyes, iso-indolinone-based pigments,
or the like, and a mixture of two or more of these pigments can be
used.
[0129] Blue (B) Pigments:
[0130] Copper phthalocyanine-based pigments, indanthrone-based
pigments, indophenol-based pigments, cyanine-based pigments,
dioxazine-based pigments, or the like, and a mixture of two or more
of these pigments can be used.
[0131] On the other hand, it is preferred to use transparent
materials (transmittance is higher than 50% in visible light
region) as a binder resin for the materials of the color filters.
They includes transparent resins (polymers) such as
polymethylmethacrylate, polyacrylate, polycarbonate,
polyvinylalcohol, polyvinylpyrrolidone, hydroxyethylcellulose, and
carboxymethylcellulose, and a mixture of two or more of these
polymers.
[0132] It is preferred to use photopolymers to which
photolithography can be applied in order to plane and discretely
place a color modulating layer in a color filter. They include
photoresist materials having a reactive vinyl group such as
acryl-based materials, methacryl-based materials, polyvinylcinnamic
acid-based materials, and cyclic rubber-based materials
(composition composed of polyisoprene, polycyclohexene, and
aromatic bis azide), and a mixture of two or more of these
materials.
[0133] In addition, printing inks (medium) using a transparent
resin can be used in order to plane and discretely place a color
modulating layer in a color filter. They include a composition
composed of a monomer, an oligomer, and a polymer of
polyvinylchloride resin, a polychlorovinylidene resin, a melamine
resin, a phenol resin, an alkyd resin, an epoxy resin, a
polyurethane resin, a polyester resin, a maleic acid resin, and a
polyamide resin, and a transparent resin such as
polymethylmethacrylate, polyacrylate, polycarbonate,
polyvinylalcohol, polyvinylpyrrolidone, hydroxyethylcellulose, and
carboxymethylcellulose, and a mixture of two or more of these
materials.
[0134] In case the color modulating layer in the color filter is
mainly composed of pigments, the color modulating layer can be
formed by using the vacuum deposition or sputtering method through
a mask of a desired color filter pattern.
[0135] On the other hand, in case the color modulating layer in a
color filter is composed of a pigment and a binder resin, a liquid
is prepared by mixing, dispersing, and solubilizing the pigment,
said resin, and an appropriate solvent in general. Then using the
liquid, a coat is formed by a method such as the spin-coat method,
the roll-coat method, the bar-coat method, and the cast method.
Then, a color modulating layer can be formed (1) by patterning with
the desired color coat pattern by the photolithography or by
patterning the desired color coat pattern by printing or the like,
and (2) by hardening with heat.
[0136] Preferred transmittance of each color filter according to
the present invention is:
[0137] R: 50% or more at 610 nm
[0138] G: 50% or more at 545 nm
[0139] B: 50% or more at 460 nm
[0140] In case particularly the color modulating layer of the color
filter is composed of pigments and a binder resin, preferred
concentration of the pigments is in such a range that the color
filter can be patterned without trouble and the luminescence of the
organic EL element can be adequately transmitted. Therefore, a
preferred content of pigments per a color filter coat including a
binder resin used is 5-50 wt. % although it depends on the kind of
the pigment.
[0141] 2) Fluorescent Layer
[0142] For the color modulating layer according to the present
invention, a fluorescent layer can be used as mentioned above. Said
fluorescent layer includes solid that is composed of e.g. only
fluorescent pigments and resins(dye), in which fluorescent pigments
are dissolved or dispersed in a pigment resin and/or a binder
resin.
[0143] Fluorescent pigments which modulate the near-ultraviolet to
violet luminescence of an organic EL element to blue luminescence
include stilbene-based pigments such as
1,4-bis(2-methylstyryl)benzene (Bis-MSB),
trans-4,4'-diphenylstilbene (DRS) and coumarin-based pigments such
as 7-hydroxy-4-methylcoumarin (Coumarin 4), and a mixture of two or
more of these pigments.
[0144] Fluorescent pigments which modulate the blue to blue green
luminescence of an organic EL element to green luminescence include
coumarin-based pigments such as
2,3,5,6-1H,4H-tetrahydro-8-trifluoromethy-
lquinolizino(9,9a,1-gh)coumarin (Coumarin 153),
3-(2'-benzothiazolyl)-7-di- ethylaminocoumarin (Coumarin 6), and
3-(2'-benzimidazolyl)-7-N,N-diethylam- inocoumarin (Coumarin 7),
and naphthalimide-based pigments such as Basic Yellow 51, Solvent
Yellow 11, and Solvent Yellow 116, and a mixture of two or more of
these pigments.
[0145] Fluorescent pigments which modulate the blue to green
luminescence of an organic EL element to orange to red luminescence
include cyanine-based pigments such as
4-dicyanomethylene-2-methyl-6-(p-dimethyla- minostyryl)-4H-pyran
(DCM), pyridine-based pigments such as
1-ethyl-2-(4-(p-dimethylaminophenyl)-1,3-butadienyl)-pyridinium-perchlora-
te (Pyridine 1), Rhodamine-based pigments such as Rhodamine B and
Rhodamine 6G, and oxazine-based pigments, and a mixture of two or
more of these pigments.
[0146] In addition, various dyes (direct dyes, acidic dyes, basic
dyes, dispersion dyes, or the like) can also be used if they
exhibit fluorescence.
[0147] Pigments prepared by blending the above-mentioned
fluorescent dyes in a pigment resins such as polymethacrylic acid
ester, polyvinylchloride, vinylchloride-vinyl acetate co-polymer,
an alkyd resin, an aromatic sulfonamide resin, an urea resin, a
melamine resin, and a benzoguanamine resin can also be used.
[0148] These fluorescent pigments can be used solely or as a
mixture. As the fluorescence modulation efficiency to red
luminescence is low in particular, the efficiency can be enhanced
by mixing those pigments.
[0149] In the organic EL display devices according to the present
invention, white luminescence can be obtained by mixing a
fluorescent pigment that modulates to above-mentioned green
luminescence and a pigment that modulates to orange to red
luminescence and by transmitting a part of the blue to blue-green
light from the organic EL element.
[0150] For a binder resin, transparent materials having a
transmittance over 50% are preferred. They include transparent
resins (polymers) such as polymethylmethacrylate, polyacrylate,
polycarbonate, polyvinylalcohol, polyvinylpyrrolidone,
hydroxyethylcellulose, and carboxymethylcellulose, and a mixture of
two or more of these resins.
[0151] In order to plane and discretely place the fluorescent
layer, it is preferred to use the photoresins to which
photolithography can be applied. They include light-hardening
resist materials having a reactive vinyl group such as acrylic
acid-based resins, methacrylic acid-based resins, polycinnamic acid
vinyl-based resins, and circularized rubber-based resins composed
of polyisoprene, polycyclohexene, and aromatic bisazide, and a
mixture of two or more of these resins.
[0152] In case the printing method is used, a printing ink (medium)
using transparent resins is selected. The transparent resins
include a monomer, an oligomer, or a polymer of a polyvinylchloride
resin, a melamine resin, phenol resin, an alkyd resin, an epoxy
resin, a polyurethane resin, a polyester resin, a maleic acid
resin, and a polyamide resin, and a polymethylmethacrylate resin, a
polyacrylate resin, a polycarbonate resin, a polyvinylalcohol
resin, a polyvinylpyrrolidone resin, a hydroxyethylcellulose resin,
and a carboxymethylcellulose resin, and a mixture of two or more of
these transparent resins.
[0153] In case the fluorescent layer is mainly composed of
fluorescent pigments, a coat is formed by the vacuum deposition or
sputtering method through a mask of a desired fluorescent layer
pattern. On the other hand, in case the fluorescent layer is
composed of a fluorescent pigment and a resin, a coat is formed by
preparing liquid by mixing, dispersing, or dissolving a fluorescent
pigment, a resin, and an appropriate solvent, and by applying a
method such as the spin coat method, the roll coat method, the bar
coat method, and the cast method. Then, generally a desired
fluorescent layer pattern is patterned by photolithography, screen
printing, or the like.
[0154] The thickness of the fluorescent layer must be in such a
range that the thickness does not prevent functions to adequately
absorb the luminescence of the organic EL element and to fluoresce.
Although the range depends more or less on the fluorescent pigment,
the range is usually 10 nm-1 mm. Preferred range is 10 nm-1 mm,
more preferred range is 5-100 .mu.m and the most preferred range is
10-50 .mu.m.
[0155] Compared with the thickness of the color filter, the
thickness of the fluorescent layer is important in general. The
reason for this is that it must absorb the luminescence of the
organic EL element adequately, although the fluorescent pigments
are more sensitive to the concentration than the color filter
pigments, and the fluorescence is stronger in case they are
dispersed or dissolved in a pigment resin or a binder resin at
lower concentration.
[0156] Briefly, it is generally necessary for the fluorescent layer
to have the absorbance of the light at a level of a color filter.
Accordingly, if the extinction coefficient of the pigment is
constant according to the equation (1) showing the Lambert-Beer
law, it is preferred that the fluorescent layer is thick in order
to enhance the fluorescence property(high absorbance of the light
).
[0157] The Lambert-Beer Law
A=.epsilon..multidot.c.multidot.l (1)
[0158] A: absorbance
[0159] .epsilon.: extinction coefficient
[0160] c: concentration of pigment
[0161] l: thickness
[0162] Although the concentration of a fluorescent pigment in the
fluorescent layer including a pigment resin and/or a binder resin
depends on the kind of the fluorescent pigment, its usual range is
1.times.10.sup.-4-1.times.10.sup.0 mol/kg, its preferred range is
1.times.10.sup.-3-1.times.10.sup.-1 mol/kg, and its more preferred
range is 1.times.10.sup.-2-5.times.10.sup.-2 mol/kg.
[0163] (2) Shading Layer
[0164] In the present invention, a shading layer is used in order
to shade undesired light emitted from an organic EL element,
prevent color-mixing in the organic EL display device, and improve
the viewing angle property.
[0165] The thickness of the shading layer is usually within the
range of 10 nm-1 mm, preferably 1 .mu.m-1 mm, and more preferably
5-100 .mu.m. In case the color modulating layer is a fluorescent
layer, a preferred thickness of the shading layer is thicker than
the color filter. As more preferred thickness of the fluorescent
layer is within the range of 5-100 .mu.m, the optimal thickness of
the shading layer is thicker than 5 .mu.m, taking the relation
T2.gtoreq.T1 concerning the thickness T1 of the color modulating
layer (fluorescent layer) and the thickness T2 of the shading layer
into account.
[0166] Although the surface shape of the shading layer can be a
grating shape or a stripe-shaped, the former is preferred (See
FIGS. 1b and 1c).
[0167] Although the cross-section of a shading layer 21 is
rectangular as shown in FIG. 9a in general, it is preferred to form
the cross-section in such a way that the width of the shading layer
21 becomes narrow gradually or stepwise from the side of the
transparent medium to the opposite side in order to improve the
visual check property by keeping the viewing angle property,
enlarging the opening of the color modulating layer 22, taking good
advantage of the light of the organic EL element 31, and enhancing
the brightness of the organic EL display device.
[0168] Briefly, as shown in FIGS. 9b and 9c, if the width of the
shading layer 21 in the side of the transparent medium is different
from that of the opposite side, and the latter is smaller than the
former (d2), the visual check property can be improved by taking
advantage of the light that was shaded in the case of the
rectangular shape, enlarging the opening of the color modulating
layer 22, and enhancing the brightness. FIG. 9b illustrates the
case of a inverted. trapezoid; FIG. 9c illustrates the case in
which it is T-shaped.
[0169] The transmittance of the shading layer is preferably 10% or
less , more preferably 1% or less in a visible region, i.e.,
400-700 nm wavelength that emits the light from the organic EL
element or the color modulating layer. In case it is higher than
10%, the light of the organic EL element or the light from the
color modulating layer might enter not only into the frontal color
modulating layer but also into the adjacent color modulating layer,
and the shading layer could not function adequately.
[0170] In addition, the reflectance efficiency of light in a
visible region of 400-700 nm wavelength of the shading layer at the
side surface that contacts at least with the color modulating layer
is preferably higher than 10%, more preferably 50% or more in order
to improve the visual check property by providing a reflectance
part 7 as shown in FIG. 10b, effectively taking out the light from
the color modulating layer 22, and enhancing the brightness of the
organic EL display device.
[0171] In addition, if a reflectance part 7 is provided, as shown
in FIG. 10c, and the shape of the shading layer 21 is a inverted.
trapezoidal shape, it is more effective. FIG. 10a illustrates the
case in which any reflectance part is not provided.
[0172] Then, the materials for the shading layer will be explained
below. Said materials include the following metals and black
pigments.
[0173] The metals include Ag, Al, Au, Cu, Fe, Ge, In, K, Mg, Ba,
Na, Ni, Pb, Pt, Si, Sn, W, Zn, Cr, Ti, Mo, Ta, and stainless steel,
and a mixture of two or more of these metals and the alloy. Oxides,
nitrides, sulfides, nitrates, and sulfates of those metals can also
be used. Carbon may be contained in the metals.
[0174] From the materials for the above-mentioned shading layer,
the pattern (placed plane and discretely) of the shading layer can
be formed in such a way that a transparent substrate coat is formed
by the method such as the sputtering method, the deposition method,
the CVD method, the ion plating method, the electrodeposition
method, the electric plating method, and the chemical plating
method, and patterning is carried out by the photolithography or
the like.
[0175] As the black pigments, pigments in which carbon black,
titanium black, aniline black, and the above-mentioned color filter
pigment are mixed to be black can be used.
[0176] A patterned shading layer can be formed by patterning the
solid that was prepared by dissolving or dispersing these black
pigments or the above-mentioned metallic materials in the binder
resin that was used in the color modulating layer, by the method
similar to the method used in the color modulating layer.
[0177] Next, the shape of a shading layer will be explained.
Concerning the shape of said shading layer, it is not limited to
but it is preferred that the width of the transparent medium side
becomes gradually or stepwise large from the opposite side.
[0178] The shading layer having this shape can be prepared by
controlling (1) the exposure energy by the UV light on the coat
surface (transparent medium side) and (2) the development condition
after a coat of a shading layer-forming material, in which a black
pigment is dissolved or dispersed in a binder resin such as
light-hardening resist, is formed on a substrate. Concretely, the
amount of exposure is reduced than the condition to form a
rectangular shading layer, and the concentration of the developing
agent and the temperature are raised, or the time for development
is lengthened. As it is originally a shading layer, even the light
of a UV region is hardly transmitted, hardening progresses more in
the nearer part to the exposed surface of the shading layer, and
hardening progress less in the farther part to the exposed surface
of the shading layer. Therefore, as the far part (the opposite side
of the transparent medium) from the exposed surface is dissolved by
treatment of a developing agent, a desired shape of a shading layer
can be obtained.
[0179] In case a metal is used as the shading layer, a rectangular
or trapezoid pattern is formed e.g. on a substrate with
light-dissolving resist (posi-resist), a metal coat is formed, the
resist pattern is lifted off, and a pattern of a shading layer
having a desired shape can be formed in the gap part of the pattern
of the resist.
[0180] In addition, on the side surface that contacts at least with
the color modulating layer of the patterned shading layer, the
reflectance coefficient in a visible region of the wavelength of
400-700 nm is preferably 10% or more , more preferably 50% or
more.
[0181] By controlling the reflectance coefficient within such a
region, the light from the color modulating layer 22 can be
effectively taken out, the brightness of the organic EL display
device can be enhanced, and the visual check property can be
improved.
[0182] The reflectance coefficient of light can be controlled by
using said metallic material as a pattern of the shading layer
directly, or by forming a coat of said metal on a pattern of the
shading layer that is composed only of a black pigment or of a
black pigment and a binder resin by a method such as the sputtering
method, the deposition method, the CDV method, and the ion plating
method. In the latter case, as it is necessary to selectively form
a coat on the side surface of the shading layer, a resist of a thin
layer is formed except on the side surface. Later, a desired
shading layer can be obtained by forming a coat with the above
mentioned metallic material by the oblique coat formation, and by
removing a metallic coat that was formed in an unnecessary part by
lifting off the resist. In this case, the thickness of the coat
formed is 0.01-1 .mu.m, preferably 0.05-0.5 .mu.m in view of
evenness and adhesion.
[0183] The coat surface reflection coefficients (ideal ones) of
main metallic materials are summarized in Table 2.
2 TABLE 2 Reflection Reflection coefficient coefficient (wavelength
in (wavelength in Metal nm) Metal nm) Ag 97.9% (500) Na 98.2% (546)
Al 91.6% (546) Ni 54.6% (440) Au 50.4% (500) Ni 60.7% (540) Cu
62.5% (500) Pb 67.5% (700) Fe 60.7% (570) Pt 59.1% (589) Ge 46.6%
(516) Si 37.5% (515) In 51.5% (500) W 43.1% (472) K 88.6% (546) Zn
82.5% (545) Mg 84.3% (546)
[0184] Although the reflection coefficients of these metals were
measured at specified wavelengths, the value is not so much changed
in a wavelength region of 400-700 nm. Other materials having a
reflection coefficient of 10% or more can also be used.
[0185] (3) Transparent Medium
[0186] The transmittance of the transparent medium, which mediates
between an organic EL element and a color-modulating and shading
layers at 400-700 nm, is preferably 50% or more. In addition, it is
more preferred that the transparent medium has an electrically
insulating property.
[0187] The transparent medium can be constructed in mono-layer or
multi-layer. The transparent medium can be the solid phase, the
liquid phase, or the gas phase.
[0188] In case a transparent medium is the solid phase such as a
polymer layer, the polymers include acrylate-based polymers and
methacrylate-based polymers one having methacrylate-based reactive
vinyl groups such as light-hardening resins and heat-hardening
resins.
[0189] The polymers also includes a monomer, a dimer, and a polymer
of melamine resin, a phenol resin, an alkyd resin, an epoxy resin,
a polyurethane resin, a polyester resin, a maleic acid resin, and a
polyamide resin, and transparent resins such as
polymethylmethacrylate, polyacrylate, polycarbonate,
polyvinylalcohol, polyvinylpyrrolidone, hydroxyethylcellulose, and
carboxymethylcellulose, and a mixture of two or more of these
transparent resins.
[0190] The polymers also include various fluorinated polymers.
[0191] In case an inorganic oxide layer is the solid phase
transparent medium, the inorganic oxides include silicon oxide
(SiO.sub.2), aluminumoxide (Al.sub.2O.sub.3), titaniumoxide
(TiO.sub.2), yttrium oxide (Y.sub.2O.sub.3), germanium oxide
(GeO.sub.2), zinc oxide (ZnO), magnesium oxide (MgO), calcium oxide
(CaO), boron oxide (B.sub.2O.sub.3), strontium oxide (SrO), barium
oxide (BaO), lead oxide (PbO), zirconium oxide (ZrO.sub.2), sodium
oxide (Na.sub.2O), lithium oxide (Li.sub.2O), and potassium oxide
(K.sub.2O), and a mixture of two or more of these oxides.
[0192] The inorganic oxide layers includes a glass plate, which is
also used as a transparent supporting substrate shown in FIG.
2a.
[0193] The glass plate includes the soda-lime glass, the barium-
and strontium-containing glass, the lead glass, the aluminosilicate
glass, the borosilicate glass, and the barium borosilicate glass,
and a mixture of two or more of these glasses. For the inorganic
oxide layer, materials which mainly contain an inorganic oxide can
be used even if nitrides such as Si.sub.3N.sub.4 are contained.
[0194] In order to attach an organic EL element to a transparent
substrate 41 that formed a color modulating layer 22 and a shading
layer 21 shown in FIG. 2a, the following adhesives can be used:
light-hardening and heat-hardening adhesives such as acrylic
acid-based oligomer and methacrylic acid-based oligomer having a
reactive vinyl group, moisture-hardening adhesives such as
2-cyanoacrylic acid ester, and heat- and chemical hardening
(two-liquid type) adhesives such as epoxy-based oligomer.
[0195] In case the gas phase and liquid phase are the transparent
medium, inert gases such as nitrogen and argon, and inert liquids
such as fluorinated hydrocarbon and silicone oil can be used. Also,
the transparent medium can be constructed by the vacuuming process.
In case these liquid materials are used as a transparent media, the
layer(coated) of the transparent media is formed by the methods
such as the spin coat method, the roll coat method, and the cast
method. In case these solid materials are used as transparent
media, the layer is formed by the methods such as sputtering,
deposition, CVD, and ion plating. Inert liquids and inert gases are
enclosed by sealing outside the luminescent region of the organic
EL element.
[0196] It is preferred that the interface where these transparent
media contact with the organic EL element is the above-mentioned
inorganic oxide layer, inert liquid, or inert gas because they can
intercept water and oxygen which promote deterioration of the
organic EL element.
[0197] In the transparent medium, it is preferred that the
difference between the refraction index n1 of the transparent
medium that contacts particularly with the color modulating layer
and the refractive index n2 of the color modulating layer is as
small as possible, because the light of the organic EL element is
not reflected on the color modulating layer but enters into it, and
more preferably that the relation .vertline.n1-n2.vertline.<0.4
is satisfied. In the case of .vertline.n1-n2.vertline..gtoreq.0.4,
as shown in the relation (2) below, the reflection of light of the
organic EL element becomes large at the interface of the color
modulating layer, and brightness of the light taken out from the
color modulating layer might be lowered finally.
[0198] The refraction indexes n1 of main materials used in the main
transparent media and the refraction indexes n2 of main resins and
binder resins which are used in the color modulating layer are
summarized in Tables 3 and 4, respectively.
3 TABLE 3 Transparent medium n1 (wavelength) Methyl methacrylate
resin 1.49 (589 nm) SiO.sub.2 1.54 (589 nm) B.sub.2O.sub.3 1.77
(546 nm) Glass 1.52 (589 nm) Tetrafluoroethylene resin 1.35 (589
nm) Fluorinated hydrocarbon 1.30 (589 nm) (FC70) Silicone oil 1.40
(589 nm) Nitrogen 1.00 (546 nm) Argon 1.00 (546 nm) Air 1.00 (546
nm) Vacuum 1.00 (546 nm)
[0199]
4 TABLE 4 Color-modulating layer (pigment resin, binder resin) n2
(wavelength) Vinylchloride resin 1.54 (589 nm) Chlorovinylidene
resin 1.60 (589 nm) Vinyl acetate resin 1.45 (546 nm) Polyethylene
resin 1.51 (589 nm) Polyester resin 1.52 (589 nm) Polystylene resin
1.59 (589 nm) Methyl methacrylate resin 1.49 (589 nm) Melamine
resin 1.60 (589 nm)
[0200] As these reflective indexes do not change much in a visible
wavelength region of 400-700 nm, the values in the table are shown
as representative ones.
[0201] The general relation between reflection coefficient (R) and
each refractive index (n1 and n2) is shown in equation (2), wherein
reflection coefficient (R) means the perpendicular reflection
coefficient.
R(reflection coefficient)=(n1-n2).sup.2/(n1+n2).sup.2 (2)
[0202] (4) Supporting Substrate
[0203] The supporting substrate 4 or 41 shown in FIGS. 2a-2c are
substrate to support the organic EL display device, and it is
preferred that the supporting substrate 41 which transmits the
light from the organic EL display device or the color modulating
layer is transparent, i.e., the transmittance of the light at a
visible wavelength region of 400-700 nm is 50% or more.
[0204] It is not necessary that the supporting substrate 4 in FIG.
2c is transparent, because it is not the side from which the light
is taken out.
[0205] As the transparent medium, the above-mentioned substrate
comprising a glass plate and a polymer material can be used.
[0206] Concerning the thickness of the plate, the thickness of 1
.mu.m-5 mm can be usually used because too thick substrate would
influence the transmittance of light.
[0207] (5) Organic EL Element
[0208] As the organic EL element according to the present
invention, the organic EL element having at least a recombining
region and a luminescent region as an organic layer is used. As
this recombining region and luminescent region exist usually in the
luminescent(emitting) layer, only luminescent region may be used as
an organic layer according to the present invention. Nevertheless,
if necessary, e.g. a positively charged hole-injecting layer, an
electron-injecting layer, an organic semiconductor layer, an
electric barrier layer, and an attachment-improving layer can also
be used.
[0209] Next, typical examples of constitution for the organic EL
element used in the present invention will be shown below, although
the organic EL element used in the present invention is not limited
to these.
[0210] a. Anode/Luminescent layer/Cathode
[0211] b. Anode/Positively charged hole-injecting layer/Luminescent
layer/ Cathode
[0212] c. Anode/Luminescent layer/Electron-injecting
layer/Cathode
[0213] d. Anode/Positively charged hole-injecting layer/Luminescent
layer/Electron-injecting layer/Cathode
[0214] e. Anode/Organic semiconductor layer/Luminescent
layer/Cathode
[0215] f. Anode/Organic semiconductor layer/Electric barrier
layer/Luminescent layer/Cathode
[0216] g. Anode/Positively charged hole-injecting layer/Luminescent
layer/Attachment-improving layer/Cathode
[0217] Among these, the constitution d is preferably used.
[0218] (5)-1. Anode
[0219] As an anode, an electrode material made of a metal, an
alloy, and an electroconductive compound, and a mixture of two or
more of these having a large work function (higher than 4 eV) is
preferably used. As examples of such an electrode material, metals
such as Au, and electroconductive transparent materials such as
CuI, ITO, SnO.sub.2, and ZnO can be cited.
[0220] The anode can be prepared by forming a thin coat of these
electrode materials by the method such as the deposition method and
the sputtering method.
[0221] In case the luminescence from the luminescent layer is taken
out from the anode in this way, it is preferred that the
transmittance to the luminescence of the anode is 10% or more. It
is also preferred that the sheet resistance of the anode is lower
than several hundreds .OMEGA./.quadrature.. Although the thickness
of the anode depends on the material, usually the range of 10 nm-1
.mu.m, preferably the range of 10-200 nm is used.
[0222] (5)-2. Luminescent Layer (Emitting Layer)
[0223] The luminescent members for the organic EL element are
mainly organic compounds. The following organic compounds are used,
depending on the desired color tones.
[0224] First, in case a luminescence from UV to violet is to be
obtained, the compound expressed by the formula (1) is used,
wherein X is a group expressed by the formula (2), wherein n is 2,
3, 4, or 5; Y is a group expressed by the formula (3). 1
[0225] At least one hydrogen atom of phenyl group, phenylene group,
or naphthyl group of the above-mentioned compounds, can be
substituted for group(s) selected from C.sub.1-C.sub.4 alkyl group,
alkoxy group, hydroxyl group, sulfonyl group, carbonyl group, amino
group, dimethylamino group, or diphenylamino group. These groups
can be bound each other to form a saturated 5- or 6-membered ring.
Para-substituted phenyl, phenylene, and naphthyl compounds are
preferred on account of a combining property and to form a smooth
deposition coat, e.g., the following compounds expressed by the
chemical formulas (4)-(8). Especially, p-quaterphenyl derivatives
and p-quinquephenyl derivatives are preferred. 2
[0226] Next, in order to obtain blue to green luminescence, optical
whitening agents such as benzothiazol-based agents,
benzoimidazol-based agents, and benzooxazol-based agents,
metal-chelating oxinoid compounds, and stilbene-based compounds can
be used.
[0227] Concrete compound names can be found e.g. in Japanese Patent
Laid-open Publication No. Sho59-194393. Typical ones are optical
whitening agents such as benzooxazol-based agents,
benzothiazol-based agents, and benzoimidazol-based agents.
[0228] In addition, other useful compounds are listed in Chemistry
of Synthetic Dyes 1971, pp. 628-637.
[0229] As the above-mentioned chelating oxinoid compounds, ones
disclosed in Japanese Patent Laid-open Publication No. Sho63-295695
can be used. As the typical ones, 8-hydroxyquinolin-based metal
complexes such as tris(8-quinolinol)aluminium (Alq) and dilithium
epinetridione can be used.
[0230] As the above-mentioned stilbene-based compounds, ones
disclosed in European Patent No. 0319881 and European Patent No.
073582 can be used.
[0231] Distyrylpyrazine derivatives disclosed in Japanese Patent
Laid-open Publication No. Hei2-252793 can also be used as materials
for the luminescent layer.
[0232] Polyphenyl-based compounds disclosed in European Patent
0387715 can also be used as materials for the luminescent
layer.
[0233] In addition to the above-mentioned optical whitening agents,
metal-chelating oxinoid compounds, and stilbene-based compounds,
12-phthaloperinone (J. Appl. Phys., Vol. 27, L713 (1988)),
1,4-diphenyl-1,3-butadiene, 1,1,4,4-tetraphenyl-1,3-butadiene (both
Appl. Phys. Lett., Vol.56, L799 (1990)), naphthalimide derivatives
(Japanese Patent Laid-open Publication No. Hei2-305886), perylene
derivatives (Japanese Patent Laid-open Publication No.
Hei2-189890), oxadiazole derivatives (Japanese Patent Laid-open
Publication No. Hei2-216791; Hamada et al., the 38th Combined
Meeting of Applied Physics-Related Associations),
aldazine-derivatives (Japanese Patent Laid-open Publication No.
Hei2-220393), pyraziline (Japanese Patent Laid-open Publication No.
Hei2-220394), cyclopentadiene derivatives (Japanese Patent
Laid-open Publication No. Hei2-289675), pyrrolopyrrole derivatives
(Japanese Patent Laid-open Publication No. Hei2-296891),
styrylamine derivatives (Appl. Phys. Lett., Vol.56, L799 (1990)),
coumarin-based compounds (Japanese Patent Laid-open Publication No.
Hei2-191694), and polymers described e.g. in International Patent
WO90/13148, and Appl. Phys. Lett., Vol. 58, 18, P1982 (1991) can
also be used as the luminescent layer.
[0234] It is preferred to use aromatic dimethylidine compounds
(disclosed in European Patent No. 0388768 or Japanese Patent
Laid-open Publication No. Hei3-231970), as the luminescence
according to the present invention, such as
4,4'-bis(2,2-di-t-butylphenylvinyl)biphenyl (DTBPBBi),
4,4'-bis(2,2-diphenylvinyl)biphenyl (DPVBi), and derivatives
thereof.
[0235] It is also preferred to use compounds expressed by the
formula (R.sub.S-Q)2-AL-O-L described e.g. in Japanese Patent
Laid-open Publication No. Hei5-258862, wherein L is
C.sub.6-C.sub.24 hydrocarbon containing a phenyl group, O-L is a
phenolate legand, Q is a substituted 8-quinolinolate legand,
R.sub.S is a substituted 8-quinolinolate ring-substituting group
selected to spatially hinder two or more substituted
8-quinolinolate ligands to bind an aluminium atom, such as
bis(2-methyl-8-quinolinolate)(p-phenylphenolate) aluminium (III)
(PC-7) and bis(2-methyl-8-quinolinolate)(1-naphtholate) aluminium
(III) (PC-17).
[0236] The method to obtain efficient blue-green mixed luminescence
using doping according e.g. to Japanese Patent Laid-open
Publication No. Hei6-9953 can also be used. In this case, the
above-mentioned luminescent members as a host, a strong fluorescent
pigment (dye) in a region from blue to green as a dopant such as
coumarin-based dyes, and similar fluorescent pigment as ones used
as the above-mentioned host can be used.
[0237] For example, luminescent members having a distyrylarylene
moiety as a host, preferably DPVBi, diphenylaminovinylarylene as a
dopant, preferably n,n-diphenylaminovinylbenzene (DPAVB) can be
used.
[0238] As luminescent layers to obtain white luminescence, the
followings can be used:
[0239] a) A luminescent layer that allows luminescence by providing
energy levels of each layer of the organic EL overlaid structure
and utilizing the tunnel injection (European Patent 0390551)
[0240] b) The same display device utilizing the tunnel injection as
a), in which a white luminescent display device is exemplified
(Japanese Patent Laid-open Publication No. Hei3-230584)
[0241] c) A two-layered luminescent layer (Japanese Patent
Laid-open Publication No. Hei2-220390, Japanese Patent Laid-open
Publication No. Hei2-216790)
[0242] d) A luminescent layer that is constructed with a plurality
of materials each having a different luminescence wavelength
(Japanese Patent Laid-open Publication No. Hei4-51491)
[0243] e) Luminescent layer in which a blue illuminant (fluorescent
peak, 380-480 nm) and a green illuminant (fluorescent peak, 480-580
nm) are overlaid, and a red fluorescent pigment is contained
(Japanese Patent Laid-open Publication No. Hei6-207170), and
[0244] f) A luminescent layer in which a blue luminescent layer
contains a blue fluorescent pigment, a green luminescent layer has
a region containing a red fluorescent pigment, and contains a green
fluorescent pigment (Japanese Patent Laid-open Publication No.
Hei7-142169)
[0245] Among these, the constitution e) is preferably used.
[0246] Followings (formulas 9-24) are red fluorescent pigment to
obtain red luminescence: 3
[0247] As a method to form a luminescent layer using the
above-mentioned materials, well-known methods such as the
deposition method, the spin coat method, and the LB method is
applicable. A "molecular piling-up coat" is most preferred for the
luminescent layer.
[0248] The "molecular piling-up coat" is a thin coat formed by
deposition from a gas-state material compound or a coat formed by
solidification from a solution- or liquid-state material compound.
The "molecular piling-up coat" is different from a thin coat
(molecularly accumulated coat) formed by the LB method with respect
to the aggregation structure, the higher structure, and the
functions caused by these. In addition, as shown in Japanese Patent
Laid-open Publication No. Sho57-51781, the luminescent layer can
also be formed by dissolving a binder such as resin and a material
compound in a solvent to make solution and by making a thin coat by
the method such as the spin coat method.
[0249] It is usually preferred that the thickness of the
luminescent layer is in a range of 5 nm-5 .mu.m.
[0250] The luminescent layer of the organic EL element has the
following functions as well:
[0251] a. Injecting function: a function that allows (1) to inject
positively charged holes from the anode or the positively charged
hole-injecting layer and (2) to inject electrons from the cathode
or the electron-injecting layer, when the electric field is
applied,
[0252] b. Transporting function: a function to transport electric
charges (electrons and positively charged holes) by the power of
the electric field,
[0253] c. Light-emitting function: a function that allows (1) to
provide a site for re-coupling an electron and a positively charged
hole and (2) to emit the light.
[0254] Although the easiness with which positively charged holes
are injected and the easiness with which electrons are injected
need not be equal, and the transportation abilities expressed by
the mobility of positively charged holes and electrons need not be
equal, it is preferred to transport one of the electric
charges.
[0255] (5)-3. Positively Charged Hole-injecting Layer
[0256] Although a positively charged hole-injecting layer is not
necessary for the display device according to the present
invention, it is preferred to use the positively charged
hole-injecting layer in order to improve the luminescence
property.
[0257] This positively charged hole-injecting layer, which is a
layer to help injection of positively charged holes into the
luminescent layer, has a high mobility of positively charged holes,
and has an ionization energy lower than 5.5 eV usually.
[0258] As a positively charged hole-injecting layer like this, a
material that transports positively charged holes to a luminescence
layer at lower electric field is preferred, and it is more
preferred if the mobility of the positively charged hole is at
least 1.times.10.sup.-6 cm.sup.2/V.multidot.s when the electric
filed of 1.times.10.sup.-41.times- .10.sup.6V/cm is applied.
[0259] There is no limitation to the positively charged
hole-injecting material like this as long as it has the
above-mentioned good properties. It can be selected from (1) the
materials usually used as a material to transport positively
charged holes in photoconductive materials or (2) well-known
materials used for positively charged hole-injecting layer of the
EL display device, such as triazole derivatives (See U.S. Pat. No.
3,112,197), oxadiazole derivatives (See U.S. Pat. No. 3,189,447),
imidazole derivatives (See Japanese Patent Publication No.
Sho37-16096), polyarylalkane derivatives (See U.S. Pat. No.
3,615,4402, U.S. Pat. No. 3,820,989, U.S. Pat. No. 3,542,544,
Japanese Patent Publication No. Sho45-555, Japanese Patent
Publication No. Sho51-10983, Japanese Patent Laid-open Publication
No. Sho51-93224, Japanese Patent Laid-open Publication No.
Sho55-17105, Japanese Patent Laid-open Publication No. Sho56-4148,
Japanese Patent Laid-open Publication No. Sho55-108667, Japanese
Patent Laid-open Publication No. Sho55-156953, Japanese Patent
Laid-open Publication No. Sho56-36656), pyrazolin derivatives and
pyrazolone derivatives (See U.S. Pat. No. 3,180,729, U.S. Pat. No.
4,278,746, Japanese Patent Laid-open Publication No. Sho55-88064,
Japanese Patent Laid-open Publication No. Sho55-88065, Japanese
Patent Laid-open Publication No. Sho49-105537, Japanese Patent
Laid-open Publication No. Sho55-51086, Japanese Patent Laid-open
Publication No. Sho56-80051, Japanese Patent Laid-open Publication
No. Sho56-88141, Japanese Patent Laid-open Publication No.
Sho57-45545, Japanese Patent Laid-open Publication No.
Sho54-112637, Japanese Patent Laid-open Publication No.
Sho55-74546), phenylenediamine derivatives (See U.S. Pat. No.
3,615,404, Japanese Patent Publication No. Sho5l-10105, Japanese
Patent Publication No. Sho46-3712, Japanese Patent Publication No.
Sho47-25336, Japanese Patent Laid-open Publication No. Sho54-53435,
Japanese Patent Laid-open Publication No. Sho54-110536, Japanese
Patent Laid-open Publication No. Sho54-119925), arylamine
derivatives (See U.S. Pat. No. 3,567,450, U.S. Pat. No. 3,180,703,
U.S. Pat. No. 3,240,597, U.S. Pat. No. 3,658,520, U.S. Patent No.
4,232,103, U.S. Pat. No. 4,175,961, U.S. Pat. No. 4,012,376,
Japanese Patent Publication No. Sho49-35702, Japanese Patent
Publication No. Sho39-27577, Japanese Patent Laid-open Publication
No. Sho55-144250, Japanese Patent Laid-open Publication No.
Sho56-119132, Japanese Patent Laid-open Publication No.
Sho56-22437, DE Patent No. 1,110,518), amino-substituted calcone
derivatives (See U.S. Pat. No. 3,526,501), oxazole derivatives (See
U.S. Pat. No. 3,257,203), styrylanthracene derivatives (See
Japanese Patent Laid-open Publication No. Sho56-46234), fluorenone
derivatives (See Japanese Patent Laid-open Publication No.
Sho54-110837), hydrazone derivatives (See U.S. Pat. No. 3,717,462,
Japanese Patent Laid-open Publication No. Sho54-59143, Japanese
Patent Laid-open Publication No. Sho55-52063, Japanese Patent
Laid-open Publication No. Sho55-52064, Japanese Patent Laid-open
Publication No. Sho55-46760, Japanese Patent Laid-open Publication
No. Sho55-85495, Japanese Patent Laid-open Publication No.
Sho57-11350, Japanese Patent Laid-open Publication No.
Sho57-148749, Japanese Patent Laid-open Publication No.
Hei2-311591), stilbene derivatives (See Japanese Patent Laid-open
Publication No. Sho61-210363, Japanese Patent Laid-open Publication
No. Sho61-228451, Japanese Patent Laid-open Publication No.
Sho61-14642, Japanese Patent Laid-open Publication No. Sho61-72255,
Japanese Patent Laid-open Publication No. Sho62-47646, Japanese
Patent Laid-open Publication No. Sho62-36674, Japanese Patent
Laid-open Publication No. Sho62-10652, Japanese Patent Laid-open
Publication No. Sho62-30255, Japanese Patent Laid-open Publication
No. Sho60-93445, Japanese Patent Laid-open Publication No.
Sho60-94462, Japanese Patent Laid-open Publication No.
Sho60-174749, Japanese Patent Laid-open Publication No.
Sho60-175052), silazane derivatives (See U.S. Pat. No. 4,950,950),
polysilane-based compounds (See Japanese Patent Laid-open
Publication No. Hei2-204996), aniline-based copolymers (See
Japanese Patent Laid-open Publication No. Hei2-282263),
electroconductive oligomers (particularly thiophene oligomer)
disclosed in Japanese Patent Laid-open Publication No. Hei1-211399,
or the like.
[0260] Although the above-mentioned compounds can be used as the
material for the positively charged hole-injecting layer, porphyrin
compounds (disclosed e.g. in Japanese Patent Laid-open Publication
No. Sho63-2956965), aromatic tertiary amine compounds and styryl
amine compounds (See U.S. Pat. No. 4,127,412, Japanese Patent
Laid-open Publication No. Sho53-27033, Japanese Patent Laid-open
Publication No. Sho54-58445, Japanese Patent Laid-open Publication
No. Sho54-149634, Japanese Patent Laid-open Publication No.
Sho54-64299, Japanese Patent Laid-open Publication No. Sho55-79450,
Japanese Patent Laid-open Publication No. Sho55-144250, Japanese
Patent Laid-open Publication No. Sho56-119132, Japanese Patent
Laid-open Publication No. Sho6l-295558, Japanese Patent Laid-open
Publication No. Sho6l-98353, Japanese Patent Laid-open Publication
No. Sho63-295695), aromatic tertiary amine compounds is more
preferably used.
[0261] Compounds such as
4,4'-bis-[N-(1-naphthyl)-N-phenylamino]biphenyl (NPD) having two
polycyclic aromatic rings in the molecule, which is described in
U.S. Pat. No. 5,061,569, and 4,4',4"-tris[N-(3-methylphenyl)-
-N-phenylamino]triphenylamine (MTDATA) in which three
triphenylamine units are linked all together in a star-burst shape,
which is described in Japanese Patent Laid-open Publication No.
Hei4-308688 can also be used.
[0262] In addition to the above-mentioned aromatic
dimethylidene-based compounds shown as the material for the
luminescent layer, inorganic compounds such as p-type Si and p-type
SiC can also be used as the materials for the positively charged
hole-injecting layer.
[0263] The positively charged hole-injecting layer can be formed by
making a thin coat from the above-mentioned compounds by the
well-known methods such as the vacuum deposition method, the spin
coat method, the cast method, and the LB method. Although there is
no special limitation to the thickness as the positively charged
hole-injecting layer, the thickness is usually in a range of 5 nm-5
.mu.m. The positively charged hole-injecting layer can be
constructed with a layer composed of one or more kinds of the
above-mentioned materials, or can be prepared by overlaying a
positively charged hole-injecting layer that is composed of another
kind of compound different from the above-mentioned positively
charged hole-injecting layer.
[0264] In addition, an organic semiconductor layer, which is a
layer helping injection of positively charged holes or electrons
into the luminescent layer, having a electroconductivity which is
higher than 1.times.10.sup.-10 S/cm is preferred. As the materials
for the organic semiconductor layer like this, electroconductive
oligomers, such as thiophene-containing oligomers and
aryl-containing oligomers, and electroconductive dendrimers, such
as arylamine-containing dendrimers, can be used.
[0265] (5)-4. Electron-injecting Layer
[0266] On the other hand, an electron-injecting layer, which helps
injection of electrons into the luminescent layer, has a large
electron mobility. An attachment-improving layer is a layer that is
composed of a material that attaches well especially to the cathode
in the electron-injecting layer.
[0267] As the materials used for the electron-injecting layer,
metal complexes of 8-hydroxyquinolin or their derivatives and
oxadizol derivatives are preferably used. As the materials used for
the attachment-improving layer, metal complexes of
8-hydroxyquinolin or their derivatives are preferably used.
[0268] As an example of the above-mentioned metal complexes of
8-hydroxyquinolin or their derivatives, metal-chelating oxinoid
compounds-including oxin (generally 8-quinolinol or
8-hydroxyquinolinone) can be cited.
[0269] As the oxadiazole derivatives, electron-transferring
compounds expressed by general formulas 25-27 can be cited, 4
[0270] wherein Ar.sup.10-Ar.sup.13are each substituted or
unsubstituted ary group, Ar.sup.10 and Ar.sup.11 can be the same or
different, Ar.sup.12 and Ar.sup.13 can be the same or different,
Ar.sup.14 is a substituted or unsubstituted arylene group, wherein
said ary group can be phenyl group, biphenyl group, anthranyl
group, perylenyl group, pyrenyl group, or the like, wherein said
arylene group can be phenylene group, naphthylene group,
biphenylene group, anthracenyl group, phenylenylene group,
pyrenylene group, or the like, wherein substituting groups can be
C.sub.1-C.sub.10 alkyl group, C.sub.1-C.sub.10 alkoxy group, cyano
group, or the like, wherein said electron-transferring compound has
preferably a thin coat-forming property.
[0271] As the above-mentioned electron-transferring compounds, the
following compounds expressed by the chemical formulas (28)-(32)
can be cited: 5
[0272] (5)-5. Cathode
[0273] As the cathode, metals, alloys, and electroconductive
compounds having a small work function (smaller than 4 eV), and a
mixture of two or more of these are used as an electrode material,
such as sodium, sodium-potassium alloy, magnesium, lithium,
magnesium-silver alloy, aluminium/aluminium oxide
(Al.sub.2O.sub.3), aluminium-lithium alloy, indium, rare earth
metals, and a mixture of two or more of these.
[0274] This cathode can be prepared by forming thin coats from
these electron materials by the methods such as deposition and
sputtering.
[0275] In addition, the sheet resistance as the cathode is
preferably lower than several hundreds .OMEGA./.quadrature., the
thickness is normally in a range of 10 nm-1 .mu.m, preferably in a
range of 50-200 nm. In the EL display device used in the present
invention, said anode and/or cathode are preferably transparent or
translucent, because this makes the transmittance of the
luminescence easy and enhances taking-out efficiency.
[0276] (5)-6. Preparation of Organic EL Element
[0277] An organic EL element can be prepared by forming the anode,
the luminescent layer, the positively charged hole-injecting layer
(if necessary), the electron-injecting layer (if necessary), and by
forming the cathode, using the above-mentioned materials and
methods. An organic EL element can also be prepared in a inverted.
order to the above-mentioned order from a cathode to an anode.
[0278] Example of preparation of the organic EL element that was
prepared on a supporting substrate serially in the order of anode/
positively charged hole-injecting layer/luminescent
layer/electron-injecting layer/cathode will be described below.
[0279] First, an anode is prepared on an appropriate substrate by
forming a thin coat composed of an anode material, with the
thickness being equal to or lower than 1 .mu.m, preferably in the
range of 10-200 nm, by the methods such as deposition and
sputtering.
[0280] Second, a positively charged hole-injecting layer is formed
on the anode. The formation of the positively charged
hole-injecting layer can be carried out by the methods such as the
vacuum deposition method, the spin coat method, the cast method,
and the LB method as described above. Among them, the vacuum
deposition method is preferred, because uniform coat can be easily
obtained and pin halls are rarely generated.
[0281] In case the positively charged hole-injecting layer is
formed by the vacuum deposition method, although the deposition
condition depends on the compounds used (material of positively
charged hole-injecting layer), and the crystal structure and
re-coupling structure of the subjective positively charged
hole-injecting layer, a deposition temperature of 50-450.degree.
C., a vacuum level of 1.times.10.sup.-7-1.times.10.sup.-3 torr, a
deposition rate of 0.01-50 nm/s, a substrate temperature of
-50-300.degree. C., and a thickness of 5 nm-5 .mu.m are generally
preferred.
[0282] Next, the luminescent layer, which is formed on the
positively charged hole-injecting layer, can also be formed by
making a thin coat from a desired organic luminescent member by the
methods such as the vacuum deposition method, sputtering, the spin
coat method, and the cast method.
[0283] Among them, the vacuum deposition method is most preferred,
because a uniform coat can be easily formed, and pin holes are
rarely generated. In case the luminescent layer is formed by the
vacuum deposition method, although the deposition condition depends
on the compounds used, the condition can be generally selected from
the conditions similar to those for the positively charged
hole-injecting layer.
[0284] Next, an electron-injecting layer is formed on the
luminescent layer. It is preferred to form the electron-injecting
layer by the vacuum deposition method, because it is necessary to
form a uniform coat as well as the positively charged
hole-injecting layer and the luminescent layer. The deposition
condition can be selected from the conditions similar to those for
the positively charged hole-injecting layer and the luminescent
layer.
[0285] Finally, the organic EL element can be obtained by
overlaying a cathode.
[0286] Although the cathode can be formed from a metal by the
methods such as the deposition method and sputtering, the former is
preferred in order to prevent the underlying organic layer from any
possible damage during coat formation.
[0287] In the preparation of the organic EL element described
above, it is preferred to prepare it from an anode to a cathode in
one batch vacuum process.
[0288] In case a direct current voltage is applied to the organic
EL element, if the polarity of the anode is "+", the that of the
cathode is "-", and a voltage of 5-40 V is applied, a luminescence
can be observed. In case the voltage is reversely applied, any
current does not flow, and luminescence is not generated at all. In
case alternating-current voltage is applied, uniform luminescence
is observed only at a phase when the polarity of the anode is "+"
and that of the cathode is "-". In this case, the shape of waves is
arbitrary.
[0289] In order to prepare an organic EL element that luminescens
being placed plane and discretely, the following methods can be
used: (1) the X-Y dot matrix method in which a stripe-shaped anode
and cathode are crossed, a direct current voltage is applied to
each electrode, and the crossed part is luminescenced, and (2) the
active matrix method that allows luminescence by forming an anode
or a cathode to a dot-shaped one, and by applying a direct current
voltage only to a specified dot part by a switching display device
such as a thin film transistor (TFT). The stripe-shaped or
dot-shaped anode and cathode can be formed (1) by etching or lifted
off by the photolithography method or (2) by the methods such as
masking deposition.
[0290] The present invention will be described more concretely by
the examples below.
EXAMPLE 1
[0291] An organic EL display device shown in FIG. 2b that satisfies
the relations d2>d1, T2=T1, and S2=S1, was prepared. On a glass
substrate (Corning 7059, 100 mm.times.100 mm.times.1.1 mm
thickness) as a supporting substrate, an acrylate-based
light-hardening resist (viscosity, 250 cps), in which 3 wt. % (on a
solid basis) carbon black was dispersed, was spin-coated, baked at
80.degree. C., and set on an exposing machine having a light source
of a mercury lamp.
[0292] Then the sample was exposed at 900 mJ/cm.sup.2 at 365 nm
through a mask by which a grating shading layer (FIG. 11), in which
a stripe pattern of a line width of 50 .mu.m (d2) and a gap of 250
.mu.m and a stripe pattern of a line width of 100 .mu.m and a gap
of 600 .mu.m orthogonalized, was obtained.
[0293] Next, development was carried out using a 1 wt. % aqueous
solution of sodium carbonate for 2 min at room temperature. Then
overall post-exposure was carried out from the glass surface side
of the substrate at 3000 mJ/cm.sup.2, and baked at 200.degree. C.
to form a pattern of the shading layer. A scanning electron
microscopic (SEM) observation revealed that the cross-section is
nearly rectangular. In addition, analysis using a spectrophotometer
showed that the transmittance of this shading layer is equal to or
lower than 10%, and the reflection coefficient is 5%, in a
wavelength region of 400-700 nm.
[0294] Then the substrate was set on a screen printer, and a blue
ink was printed in the intervals of the pattern of the shading
layer using a plate by which a dot pattern (area S2, See FIG. 12)
of a stripe arrangement of 250 .mu.m.times.600 .mu.m is
obtained.
[0295] Said ink was prepared by mixing/dispersing 2.8 wt. % (on a
solid basis) copper phthalocyanine-based pigment (C.I. Pigment Blue
15:6), 0.2 wt. % (on a solid basis) dioxazine-based pigment (C.I.
Pigment Violet 23), 97 wt. % polyester resin PET9100 (Jujo Chem.
Ind. Co.) as a binder resin, and cyclohexanone as a solvent.
[0296] Then the printed ink was baked at 160.degree. C. to obtain a
pattern of a blue color filter layer having a thickness of 20
.mu.m. The reflective index of the color filter layer obtained was
1.50 at 589 nm.
[0297] Then the plate was transferred by 300 .mu.m in parallel to a
perpendicular direction from the stripe arrangement of the pattern
of the blue color filter layer, the ink for the fluorescent layer A
was printed in other intervals of the patterned shading layer.
[0298] Said ink was prepared by mixing/dispersing 0.03 mol/kg (on a
solid base) Coumarin 6, polyester resin PET9100 as a binder resin,
and cyclohexanone as a solvent.
[0299] Then the printed ink was baked at 160.degree. C. to obtain
the fluorescent layer A pattern having a thickness of 20 .mu.m. The
refractive index of the fluorescent layer A was 1.52 at 589 nm.
[0300] Then the plate was further transferred by 300 .mu.m in
parallel to a perpendicular direction from the stripe arrangement
of the pattern of the fluorescent layer A, the ink for the
fluorescent layer B was printed in other intervals of the patterned
shading layer.
[0301] Said ink was prepared by mixing/dispersing (1) a fluorescent
pigment (30 wt. % on a solid basis) that was prepared by admixing
0.03 mol/kg (on a solid base) Coumarin 6, 4 wt % (per fluorescent
pigment) Rhodamine 6G, and 4 wt. % (per fluorescent pigment)
Rhodamine B in a benzoguanamine resin, (2) a polyester resin
PET9100 (70 wt. % on a solid basis) as a binder resin, and (3)
cyclohexanone as a solvent.
[0302] Then the printed ink was baked at 160.degree. C. to obtain a
pattern of a fluorescent layer B having a thickness of 20 .mu.m.
The refractive index of the color filter layer obtained was 1.52 at
589 nm.
[0303] A substrate, on which a shading layer and three kinds of the
color modulating layers are plane and discretely placed, was
prepared in this way. It was constructed in such a way that the
relation T1=T2 is satisfied, with T1 being the thickness of the
shading layer, and T2 being the thickness of each of three kinds of
color modulating layers.
[0304] A part of the shading layer and the color modulating layers
was mechanically scraped in order to observe the luminescence
brightness and chromaticity of the organic EL element to overlay
later.
[0305] Then on this substrate, acrylate-based thermosetting type
resin (Nippon Steel Chem. Co. V259PA) was spin-coated as a
transparent medium, and baked at 80.degree. C. The sample was
further baked at 160.degree. C., and polished/ground to the
smoothness within .+-.0.1 .mu.m if necessary. The refractive index
of this transparent medium was 1.50 at 589 nm.
[0306] In addition, as a protective coat for the transparent
medium, silicon oxide (SiO.sub.2) was sputtered at a substrate
temperature of 160.degree. C. at 1.times.10.sup.-6 torr. The
thickness of the silicon oxide was 0.5 .mu.m.
[0307] The overall thickness on the shading layer in the
transparent medium prepared as described above was ca. 10 .mu.m
(corresponding to d1), and the relation d2>d1 was satisfied. The
relation .vertline.n1-n2.vertline.<0.4 was also satisfied,
judging from refractive indexes of the kinds of the resins
used.
[0308] Then an organic EL element was prepared. First, a substrate
was heated to 160.degree. C., and a transparent electrode (anode),
which is composed of ITO (indium-tin oxide) and has a thickness of
0.15 .mu.m and surface resistance of 20 .OMEGA./.quadrature., was
prepared by sputtering on a silicon oxide coat at 1.times.10.sup.-6
torr.
[0309] Next a positive type photoresist (Fuji-Hunt Electronics
Technology Co., HPR204) was spin-coated on ITO, and baked at
80.degree. C. Then, after the position was adjusted to the shading
layer pattern through a mask by which a stripe-shaped ITO pattern
(line width, 250 .mu.m; gap, 50 .mu.m; See FIG. 13) was obtained,
exposure was carried out at 100 mJ/cm.sup.2 by an exposing
machine.
[0310] Next the resist was developed with a 2.38% aqueous solution
of tetramethylammonium hydroxide (TMAH), post-baked at 120.degree.
C., and a resist pattern was obtained.
[0311] Then the substrate was dipped into a 47 wt. % aqueous
solution of hydrogen bromide at room temperature, ITO where the
resist pattern are exposed, was etched to remove the resist, and a
stripe-shaped ITO pattern (line width, 250 .mu.m; gap, 50 .mu.m)
was formed.
[0312] Next this substrate, on which an ITO pattern was formed, was
washed with isopropyl alcohol (IPA), UV-washed, and was fixed on a
substrate holder of a depositing machine (ULVAC Japan Co.). MTDATA
and NPD as positively charged hole-injecting materials, DPVBi as a
luminescent member, DPAVB as a dopant, and Alq as an
electron-injecting material were placed on a molybdenum resistance
heating boat, Ag as a second metal of the cathode was put on a
tungsten filament, and Mg as an electron-injecting material of the
cathode was put on a molybdenum boat, each in order to use as
depositing sources.
[0313] Then, the vacuum container was evacuated down to
5.times.10.sup.-7 torr, overlaying was carried out in the following
order. From the deposition of a positively charged hole-injecting
layer to that of a cathode, the vacuum was continuously
maintained.
[0314] First, MTDATA was deposited at a deposition rate of 0.1-0.3
nm/s up to a thickness of 200 nm as a positively charged
hole-injecting layer. Then, NPD was deposited at a deposition rate
of 0.1-0.3 nm/s up to a thickness of 20 nm as another positively
charged hole-injecting layer.
[0315] In addition, as a luminescent layer, DPVBi was deposited at
a deposition rate of 0.1-0.3 nm/s, and DPAVB was deposited at a
deposition rate of 0.05 nm/s, up to an overall thickness of 40 nm
(weight ratio of dopant per host material was 1.2-1.6).
[0316] In addition, as an electron-injecting layer, Alq was
deposited at a deposition rate of 0.1-0.3 nm/s up to a thickness of
20 nm.
[0317] In addition, as a cathode, Mg and Ag were simultaneously
deposited through a mask, which is perpendicular to the anode ITO
stripe pattern, by which a stripe pattern (line width, 600 .mu.m;
gap, 100 .mu.m; See FIG. 14) is formed, wherein Mg was deposited at
a deposition rate of 1.3-1.4 nm/s, and Ag was deposited at a
deposition rate of 0.1 nm/s up to a thickness of 200 nm.
[0318] When a direct current voltage of 8 V was applied between the
anode and cathode in the organic EL element (FIGS. 2b, 3b) that was
obtained in this way, a part (dot pattern S1 of 250 .mu.m.times.600
.mu.m), where the anode and the cathode crosses and the direct
current voltage was applied, luminesced. The luminescence
brightness of the organic EL element, which could be observed from
the part where a shading layer and a modulating layer had been
scraped, was 100 cd/m.sup.2, and a blue color having the
chromaticity of x=0.16, y=0.24 in CIE chromaticity coordinates (JIS
Z 8701) was observed.
[0319] In addition, the luminescence brightness of the light
observed from the blue color filter was 42 cd/m.sup.2, and a blue
color having a high color purity and chromaticity of x=0.14, y=0.12
was observed.
[0320] In addition, the luminescence brightness of the light
observed from the fluorescent layer A was 120 cd/m.sup.2, and a
yellowish green color having the chromaticity of x=0.28, y=0.62 was
observed.
[0321] In addition, the luminescence brightness of the light
observed from the fluorescent layer B was 30 cd/m.sup.2, and a red
color having the chromaticity of x=0.60, y=0.31 was observed.
[0322] It was constructed in such a way that the area S1 of the
luminescent region of the organic EL element is equal to the area
S2 of the region of the color modulating layer (S1=S2).
[0323] By driving the organic EL display device obtained in this
way, luminescence of a desired intrinsic color could be obtained
from each color modulating layer. The viewing angle (See FIG. 4)
that is defined as a range in which color-change (color-mixing)
does not occur was .+-.80.degree., which is a wide range that does
not cause any practical problem.
EXAMPLE 2
[0324] An organic EL display device, shown in FIG. 2b, which
satisfies the relations d2>d1, T1 (20 .mu.m)>T2 (15 .mu.m),
and S2=S1, was prepared. When the color modulating layer in Example
1, i.e., a blue color filter, fluorescent layer A, and fluorescent
layer B were prepared, an EL element (FIG. 5d) was prepared under
the same condition as Example 1 except that viscosity of each ink
was reduced by increasing the amount of solvent, and each thickness
was reduced to 15 .mu.m.
[0325] By driving the organic EL display device obtained in this
way, luminescence of the desired intrinsic color could be obtained
from each color modulating layer. The viewing angle (See FIG. 4)
that is defined as a range in which color-change (color-mixing)
does not occur was .+-.80.degree., which is a wide range that does
not cause any practical problem.
EXAMPLE 3
[0326] An organic EL display device, shown in FIG. 2b, which
satisfies the relations d2>d1, T2=T1, and S2>S1, was
prepared. An EL element (FIG. 6c) was prepared under the same
condition as Example 1 except that the transparent electrode
(anode) of the organic EL element was a stripe-shaped ITO pattern
(line width, 200 .mu.m; gap, 100 .mu.m). In Example 3 also, the
device was constructed in such a way that the relations d2>d1
and T2=T1 were satisfied.
[0327] Area S1 of the luminescence region of the organic EL element
is 200 .mu.m.times.600 .mu.m (dot pattern), and area S2 of each
color modulating layer is 250 .mu.m.times.600 .mu.m (dot pattern).
Therefore, the relation S1<S2 is also satisfied.
[0328] By driving the organic EL display device obtained in this
way, luminescence of a desired intrinsic color could be obtained
from each color modulating layer. The viewing angle (See FIG. 4)
that is defined as a range in which color-change (color-mixing)
does not occur was .+-.85.degree., which is wider than Examples 1
and 2.
EXAMPLE 4
[0329] An organic EL display device, shown in FIG. 2a, which
satisfied the relations d2=d1, T2=T1, and S2=S1, was prepared. As a
supporting substrate, a glass substrate (barium borosilicate glass,
100 mm.times.10 mm.times.0.05 mm thick), on which a coat of a
transparent electrode (anode) of ITO (indium tin oxide) having a
thickness of 0.15 .mu.m and a surface resistance of 20
.OMEGA./.quadrature. was formed, was prepared by sputtering,
wherein the refractive index of the glass substrate was 1.52 at 589
nm, and was used as a transparent medium.
[0330] Next, a substrate, on which a shading layer and a color
modulating layer are placed plane discretely on the opposite side
of the ITO coat surface under the same condition as Example 1, was
prepared.
[0331] In addition, ITO was patterned under the same condition as
Example 1, wherein the thickness on the shading layer of the
transparent medium was 50 .mu.m (d1), and the relations d2=d1 and
.vertline.n1-n2.vertline.&- lt;0.4 were satisfied.
[0332] The organic EL display device was prepared under the same
condition as Example 1 (See FIGS. 2a and 3b), wherein it is
constructed in such a way that the area S1 of the luminescence
region of the organic EL element is equal to the area S2 of the
region of the color modulating layer, i.e., S1=S2.
[0333] In this organic EL display device obtained, luminescence of
the desired intrinsic color could be obtained from each color
modulating layer. The viewing angle in which color-change
(color-mixing) does not occur was .+-.45.degree., which was a level
that does not cause any practical problem.
EXAMPLE 5
[0334] An organic EL display device, shown in FIG. 2c, which
satisfies the relations d2>d1, T2=T1, and S2=S1, was prepared.
On a glass substrate (Corning 7059, 100 mm.times.100 mm.times.1.1
mm thick) as a supporting substrate, acrylate-based light-hardening
resist V259PA (Nippon Steel Chem. Co.), in which 30 wt. % (on a
solid basis) carbon black was dispersed, was spin-coated, and baked
at 80.degree. C. Then the sample was further baked at 200.degree.
C. to form a black coat with a thickness of 2 .mu.m.
[0335] Then the opposite side of the black coat was washed with
IPA, UV-washed, and fixed in a substrate holder of a depositing
machine (ULVAC Japan Co.). MTDATA and NPD as positively charged
hole-injecting materials, DPVBi as a luminescent member, DPAVB as a
dopant, and Alq as an electron-injecting material were placed on a
molybdenum resistance heating boat, Ag was put on a tungsten
filament as a second metal of the cathode, and Mg was put on a
molybdenum boat as an electron-injecting metal of the cathode, in
order to use both as depositing sources.
[0336] Then, the vacuum container was evacuated down to
5.times.10.sup.-7 torr, a coat having a pattern of a cathode was
formed through a mask by which a stripe pattern of 600 .mu.m line
width and 100 .mu.m gap was made, then a coat from an
electron-injecting layer to a positively charged hole-injecting
layer was formed. When serially overlaying positively charged
hole-injecting layers was carried out from a cathode, the vacuum
was continuously maintained.
[0337] As a cathode, Mg and Ag were simultaneously deposited. Mg
was deposited at a deposition rate of 1.3-1.4 nm/s, and Ag was
deposited at a deposition rate of 0.1 nm/s, up to the overall
thickness of 200 nm.
[0338] Next, as an electron-injecting layer, Alq was deposited at a
deposition rate of 0.1-0.3 nm/s up to a thickness of 20 nm.
[0339] In addition, as a luminescent layer, DPVBi was deposited at
a deposition rate of 0.1-0.3 nm/s, and DPAVB was deposited at a
deposition rate of 0.05 nm/s, up to an overall thickness of 40 nm
(weight ratio of dopant per host material is 1.2-1.6).
[0340] In addition, as a positively charged hole-injecting layer,
NPD was deposited at a deposition rate of 0.1-0.3 nm/s, up to an
overall thickness of 20 nm. As another positively charged
hole-injecting layer, MTDATA was deposited at a deposition rate of
0.1-0.3 nm/s, up to an overall thickness of 40 nm.
[0341] Then, this substrate was transferred to a sputtering
machine, an organic EL element was prepared by forming a coat with
ITO as a transparent electrode (anode) of a resistance of 20
.OMEGA./.quadrature. at room temperature through a mask by which a
stripe pattern of a line width of 250 .mu.m and a gap of 5 .mu.m
(See FIG. 13) is obtained, wherein the mask was placed in such a
way that a cathode and an anode crosses perpendicularly and
terminals of each electrode could be taken out.
[0342] Then epoxy-based light-hardening adhesive 3113 (Three Bond
Co.) was applied to the vicinities of the cathode-anode crossing
region using a dispenser in a width of ca. 1 mm keeping a space
partly.
[0343] On the other hand, the substrates prepared under the same
condition as Example 1, in which a shading layer and different
color modulating layers were placed in the plane and discrete
manners, were attached each other so that an organic EL element, a
shading layer, and a color modulating layer are placed oppositely,
the adhesive was hardened by radiating UV light only to the part
where the adhesive was applied.
[0344] Then, under the atmosphere of nitrogen, a fluorinated
hydrocarbon (3M Co., USA, FC-70), as a transparent medium, was
injected through a gap of the adhesive by using a syringe.
[0345] Next, said adhesive was further filled into the gap of the
adhesive, and hardened by UV light as described above. The
refractive index of the fluorinated hydrocarbon was 1.30 at 589 nm.
The distance (gap) between the organic EL element and the shading
layer was 10 .mu.m (d1), and the relations d2>d1 and
.vertline.n1-n2.vertline.<0.4, were satisfied.
[0346] After the organic EL element was prepared in this way (See
FIGS. 2c, 3b), when a direct current voltage of 8 V was applied
between the anode and the cathode, the part (dot pattern of 250
.mu.m.times.600 .mu.m, S1) where the anode and the cathode crosses,
luminesced. In addition, the luminescence brightness of the organic
EL element observed from the part, where the shading layer and the
modulating layer had been scraped, was 100 cd/m.sup.2, and blue
luminescence having a chromaticity in CIE chromaticity coordinates
(JIS Z 8701) of x=0.16 and y=0.24 was obtained.
[0347] The luminescence brightness of the light observed from a
blue color filter was 40 cd/m.sup.2, and blue luminescence having a
chromaticity of x=0.14 and y=0.12 was obtained.
[0348] In addition, the luminescence brightness of the light
observed from a fluorescent layer A was 110 cd/m.sup.2, and
yellowish green luminescence having a chromaticity of x=0.28 and
y=0.62 was obtained.
[0349] In addition, the luminescence brightness of the light
observed from a fluorescent layer B was 28 cd/m.sup.2, and red
luminescence having a chromaticity of x=0.60 and y=0.31 was
obtained.
[0350] The area S1 of the luminescence region of the organic EL
element was equal to he area S2 of the region of the color
modulating layer, satisfying the relation S1=S2.
[0351] By preparing the organic EL display device as described
above, and driving it, luminescence of an intrinsic color could be
obtained from each color modulating layer. The viewing angle (See
FIG. 4) that is defined as a range in which color-change
(color-mixing) does not occur was .+-.80.degree., which is a level
that does not cause any practical problem.
EXAMPLE 6
[0352] An organic EL display device, shown in FIG. 2b, which
satisfied the relations d2>d1, T2=T1, and S2=S1, and all the
color modulating layer was a color filter, was prepared. On a glass
substrate (Corning 7059, 100 mm.times.100 mm.times.1.1 mm thick) as
a supporting substrate, acrylate-based light-hardening resist
V259PA (Nippon Steel Chem. Co.) in which 30 wt. % (on a solid
basis) carbon black was dispersed was spin-coated, and baked at
80.degree. C. Then the resist coat was exposed to the light at 300
mJ/cm.sup.2 at 365 nm by an exposing machine having a mercury lamp
as a light source through a mask so that a pattern of the shading
layer shown in FIG. 11 was obtained.
[0353] Then development was carried out using a 1 wt. % aqueous
solution of sodium carbonate for 2 min at room temperature. The
substrate was baked at 200.degree. C. to form a pattern of the
shading layer. A scanning electron microscopic (SEM) observation
revealed that the cross-section is nearly rectangular.
[0354] In addition, analysis using a spectrophotometer showed that
the transmittance of this shading layer is lower than 10%, and the
reflection coefficient is 5%, at a wavelength of 400-700 nm.
[0355] Next, acrylate-based heat-hardening resin V259PA (Nippon
Steel Chem. Co., equivalent to 70 wt. % on a solid basis), in which
28 wt. % (on a solid basis) copper phthalocyanine-based pigment
(C.I. Pigment Blue 15:6) and 2 wt. % (on a solid basis)
dioxazine-based pigment (C.I. Pigment Violet 23) were dispersed,
was spin-coated, and baked at 80.degree. C. Then the position was
adjusted to the shading layer pattern through a mask so that the
pattern (S2) of the shading layer shown in FIG. 12 was obtained.
Then the resist coat was exposed to the light at 300 mJ/cm.sup.2 at
365 nm by an exposing machine having a mercury lamp as a light
source.
[0356] Then development was carried out using a 1 wt. % aqueous
solution of sodium carbonate for 2 min at room temperature. Then
the sample was baked at 200.degree. C. to form a pattern of the
blue color filter. The thickness of the blue color filter obtained
was 2 .mu.m, and its refractive index was 1.50 at 589 nm.
[0357] Next, acrylate-based heat-hardening resin V259PA (Nippon
Steel Chem. Co., equivalent to 70 wt. % on a solid basis), in which
23 wt. % (on a solid basis) halogenated copper phthalocyanine-based
pigment (C.I. Pigment Green 36) and 7 wt. % (on a solid basis)
azo-based pigment (C.I. Pigment Yellow 83) were dispersed, was
spin-coated, and baked at 80.degree. C. Then the position was
changed by 300 .mu.m parallel to the direction perpendicular to the
stripe arrangement of the blue color filter through a mask so that
the pattern of the color modulating layer shown in FIG. 12 could be
obtained. Then the resist coat was exposed to the light at 300
mJ/cm.sup.2 at 365 nm by an exposing machine having a mercury lamp
as a light source.
[0358] Then development was carried out using a 1 wt. % aqueous
solution of sodium carbonate for 2 min at room temperature. Then
the sample was baked at 200.degree. C. to form a pattern of the
green color filter. The thickness of the green color filter
obtained was 2 .mu.m, and its refractive index was 1.50 at 589
nm.
[0359] Next, acrylate-based heat-hardening resin V259PA (Nippon
Steel Chem. Co., equivalent to 70 wt. % on a solid basis), in which
24 wt. % (on a solid basis) anthraquinone-based pigment (C.I.
Pigment Red 177) and 6 wt. % (on a solid basis) azo-based pigment
(C.I. Pigment Yellow 6) were dispersed, was spin-coated, and baked
at 80.degree. C. Then the position was changed by 300 .mu.m
parallel to the direction perpendicular to the stripe arrangement
of the green color filter through a mask so that the pattern of the
color modulating layer shown in FIG. 12 could be obtained. Then the
resist coat was exposed to the light at 300 mJ/cm.sup.2 at 365 nm
by an exposing machine having a mercury lamp as a light source.
[0360] Then development was carried out using a 1 wt. % aqueous
solution of sodium carbonate for 2 min at room temperature. Then
the sample was baked at 200.degree. C. to form a pattern of the red
color filter. The thickness of the red color filter obtained was 2
.mu.m, and its refractive index was 1.50 at 589 nm.
[0361] A substrate, in which a shading layer and color modulating
layer (color filter) were plane and discretely placed and the
relation T1=T2 was satisfied, was prepared as described above,
wherein a very little part of the color modulating layer was
mechanically scraped for convenience' sake in order to observe the
luminescence brightness and chromaticity of the organic EL element
to overlay later.
[0362] In addition, the transparent electrode (ITO pattern, See
FIG. 13), which is an anode in the transparent medium and organic
EL element, was formed under the same condition as Example 1 so
that the relation d2>d1 was satisfied.
[0363] Then the substrate was washed with IPA, UV-washed, and fixed
in a substrate holder of a depositing machine (ULVAC Japan Co.).
MTDATA and NPD as positively charged hole-injecting materials,
DPVBi and PAVBi as a luminescence material, Rubrene, and Alq as an
electron-injecting material were placed on a molybdenum resistance
heating boat, Ag as a second metal of the cathode was put on a
tungsten filament, and Mg as an electron-injecting metal of the
cathode was put on a molybdenum boat, in order to use both as
deposition sources.
[0364] Then, after the vacuum container was evacuated down to
5.times.10.sup.-7 torr, coats were serially formed in the following
order. When overlaying was carried out from a cathode to a
positively charged hole-injecting layer, the vacuum was
continuously maintained. A pattern (FIG. 14) of a cathode was
formed through a mask by which a coat could be formed to be a
perpendicularly crossing stripe pattern of 600 .mu.m line width and
100 .mu.m gap.
[0365] First, as a positively charged hole-injecting layer, MTDATA
was deposited at a deposition rate of 0.1-0.3 nm/s, up to a
thickness of 200 nm, and NPD was deposited at a deposition rate of
0.1-0.3 nm/s, up to a thickness of 20 nm.
[0366] Then, as a luminescent layer, DPVBi was deposited at a
deposition rate of 0.1-0.3 nm/s, up to a thickness of 50 nm, and at
the same time PAVBI was deposited at a deposition rate of
0.003-0.009 nm/s to be contained in DPVBI.
[0367] Next, as an electron-injecting layer, Alq was deposited at a
deposition rate of 0.1-0.3 nm/s up to a thickness of 20 nm, in
which Rubrene was contained by simultaneously depositing at a
deposition rate of 0.0005-0.0015 nm/s as a second luminescent
layer.
[0368] Finally, as a cathode, Mg and Ag were simultaneously
deposited. Mg was deposited at a deposition rate of 1.3-1.4 nm/s,
and Ag was deposited at a deposition rate of 0.1 nm/s, up to the
overall thickness of 200 nm.
[0369] When a direct current voltage of 9 V was applied between the
anode and the cathode of the organic EL element (See FIG. 2b, 3b)
that was obtained in this way, a part (dot pattern S1 of 250
.mu.m.times.600 .mu.m), where the anode and the cathode crosses,
luminesced. The luminescence brightness of the organic EL element,
which could be observed from the part where a shading layer and a
modulating layer had been scraped, was 100 cd/m.sup.2, and a white
color having the chromaticity of x=0.25, y=0.28 in CIE chromaticity
coordinates (JIS Z 8701) was observed.
[0370] In addition, the luminescence brightness of the light
observed from the blue color filter was 10 cd/m.sup.2, and a blue
color having the chromaticity of x=0.10, y=0.15 was observed.
[0371] In addition, the luminescence brightness of the light
observed from the green color filter was 45 cd/m.sup.2, and a
yellowish green color having the chromaticity of x=0.28, y=0.62 was
observed.
[0372] In addition, the luminescence brightness of the light
observed from the red color filter was 15 cd/m.sup.2, and a red
color having the chromaticity of x=0.60, y=0.31 was observed.
[0373] The area S1 of the luminescence region of the organic EL
element was equal to he area S2 of the region of the color
modulating layer, satisfying the relation S1=S2.
[0374] By preparing the organic EL display device as described
above, and driving it, luminescence of an intrinsic color could be
obtained from each color modulating layer. The viewing angle (See
FIG. 4) that is defined as a range in which color-change
(color-mixing) does not occur was .+-.80.degree., which is a level
that does not cause any practical problem.
EXAMPLES 7-10
[0375] In Examples 7-10, organic EL display devices were prepared
under the same condition as Example 1 except that the relation
between d2 and d1, the relation between T1 and T2, and that the
relation between S1 and S2 were changed within a range specific to
the present invention. In Example 7, an organic EL display device,
which satisfies the relations d2>d1, T2<T1, and S2>S1, was
prepared. In Example 8, an organic EL display device, which
satisfies the relations d2=d1, T2<T1, and S2>S1, was
prepared. In Example 9, an organic EL display device, which
satisfies the relations d2=d1, T2<T1, and S2=S1, was prepared.
In Example 10, an organic EL display device, which satisfies the
relations d2=d1, T2=T1, and S2>S1, was prepared. And viewing
angles and color-mixing properties of the organic EL display
devices prepared were determined. The results of Examples 7-10 as
well as the results of Examples 1-6 are summarized in Table 5.
[0376] As shown in Table 5, mixing of colors from each color
modulating layer did not occur in each organic EL display device
prepared, and luminescence of an intrinsic color was obtained. The
X and Y values in the CIE chromaticity coordinates with respect to
luminescence from each color modulating layer were determined,
resulting that shift of said values was smaller than 0.02.
[0377] The absolute value of each viewing angle (See FIG. 4) that
is defined as a range in which color-change (color-mixing) does not
occur was equal to or more than 45.degree., which is a level that
does not cause any practical problem. Among the organic EL display
devices tested, that of Examples 3 and 7, which satisfy the
relations d2>d1, T2<T1, and S2>S1, and gave a viewing
angle of 85.degree., was most excellent.
5 Viewing d.sub.1 d.sub.2 The relation T.sub.1 T.sub.2 The relation
S.sub.1 S.sub.2 The relation angle Color (.mu.m) (.mu.m) betw.
d.sub.1 and d.sub.2 (.mu.m) (.mu.m) betw. T.sub.1 and T.sub.2
(.mu.m) (.mu.m) betw. S.sub.1 and S.sub.2 (.degree.) mixing Examp.
1 10 50 d.sub.1 < d.sub.2 20 20 T.sub.1 = T.sub.2 250 .times.
600 250 .times. 600 S.sub.1 = S.sub.2 .+-.80 No Examp. 2 10 50
d.sub.1 < d.sub.2 20 15 T.sub.1 > T.sub.2 250 .times. 600 250
.times. 600 S.sub.1 = S.sub.2 .+-.80 No Examp. 3 10 50 d.sub.1 <
d.sub.2 20 20 T.sub.1 = T.sub.2 200 .times. 600 250 .times. 600
S.sub.1 < S.sub.2 .+-.85 No Examp. 4 50 50 d.sub.1 = d.sub.2 20
20 T.sub.1 = T.sub.2 250 .times. 600 250 .times. 600 S.sub.1 =
S.sub.2 .+-.45 No Examp. 5 10 50 d.sub.1 < d.sub.2 20 20 T.sub.1
= T.sub.2 250 .times. 600 250 .times. 600 S.sub.1 = S.sub.2 .+-.80
No Examp. 6 10 50 d.sub.1 < d.sub.2 2 2 T.sub.1 = T.sub.2 250
.times. 600 250 .times. 600 S.sub.1 = S.sub.2 .+-.80 No Examp. 7 10
50 d.sub.1 < d.sub.2 20 15 T.sub.1 > T.sub.2 200 .times. 600
250 .times. 600 S.sub.1 < S.sub.2 .+-.85 No Examp. 8 50 50
d.sub.1 = d.sub.2 20 15 T.sub.1 > T.sub.2 200 .times. 600 250
.times. 600 S.sub.1 < S.sub.2 .+-.60 No Examp. 9 50 50 d.sub.1 =
d.sub.2 20 15 T.sub.1 > T.sub.2 250 .times. 600 250 .times. 600
S.sub.1 = S.sub.2 .+-.45 No Examp. 10 50 50 d.sub.1 = d.sub.2 20 20
T.sub.1 = T.sub.2 200 .times. 600 250 .times. 600 S.sub.1 <
S.sub.2 .+-.60 No Examp. 11 10 50 d.sub.1 < d.sub.2 8 6.5
T.sub.1 > T.sub.2 250 .times. 600 250 .times. 600 S.sub.1 =
S.sub.2 -- No Comp. Examp. 1 100 50 d.sub.1 > d.sub.2 20 20
T.sub.1 = T.sub.2 250 .times. 600 250 .times. 600 S.sub.1 = S.sub.2
.+-.30 No Comp. Examp. 2 70 50 d.sub.1 > d.sub.2 10 20 T.sub.1
< T.sub.2 250 .times. 600 250 .times. 600 S.sub.1 = S.sub.2
.+-.40 Yes Comp. Examp. 3 60 50 d.sub.1 > d.sub.2 20 20 T.sub.1
= T.sub.2 290 .times. 600 250 .times. 600 S.sub.1 > S.sub.2
.+-.30 Yes Comp. Examp. 9 110 50 d.sub.1 > d.sub.2 8 6.5 T.sub.1
> T.sub.2 250 .times. 600 250 .times. 600 S.sub.1 = S.sub.2 --
Yes/blot
EXAMPLE 11
[0378] An organic EL display device, shown in FIG. 2b, which
satisfies the relations d2>d1, T2<T1, and S2=S1, and all the
color modulating layer is of one kind, was prepared. On a glass
substrate (Corning 7059, 100 mm.times.100 mm.times.1.1 mm thick) as
a supporting substrate, acrylate-based light-hardening resist
V259PA (Nippon Steel Chem. Co.) in which 3 wt. % (on a solid basis)
carbon black was dispersed was spin-coated, and baked at 80.degree.
C. Then the resist coat was exposed to the light by an exposing
machine having a mercury lamp as a light source.
[0379] Then the sample was exposed at 900 mJ/cm.sup.2 at 365 nm
through a mask by which a grating shading layer (See FIG. 11), in
which a stripe pattern of a line width of 50 .mu.m (d.sub.2) and a
gap of 250 .mu.m and a stripe pattern of a line width of 100 .mu.m
and a gap of 250 .mu.m orthogonalize, was obtained.
[0380] Then development was carried out using a 1 wt. % aqueous
solution of sodium carbonate for 2 min at room temperature. Then
overall exposure was carried out from the glass side at 300
mJ/cm.sup.2, and baked at 200.degree. C. to form a pattern of the
shading layer.
[0381] The thickness of the shading layer obtained was 8.0 .mu.m. A
scanning electron microscopic (SEM) observation revealed that the
cross-section is nearly rectangular. In addition, analysis using a
spectrophotometer showed that the transmittance of this shading
layer is equal to or lower than 10%, and the reflection coefficient
is 5%, at a wavelength of 400-700 nm.
[0382] Then, a fluorescent pigment composition was prepared by
admixing Coumarin 6, 4 wt. % rhodamine 6G (per benzoguanamine
resin), and 4 wt. % Rhodamine B (per benzobguanamine resin) in a
benzoguanamine resin. A resist material (color modulating
layer-forming material) was prepared by mixing the fluorescent
pigment composition obtained and acrylate-based heat-hardening
resin V259PA (Nippon Steel Chem. Co., equivalent to 70 wt. % on a
solid basis).
[0383] The weight ratios were as follows: Coumarin 6, 0.03 mol per
1 kg of the sum of the fluorescent pigment, the benzoguanamine
resin, and solid of the light-hardening resist; the fluorescent
pigment, 30 wt. %; solid of the light-hardening resist, 70 wt.
%.
[0384] Next, the resist material obtained was spin-coated on a
patterned shading layer, and baked at 80.degree. C. Then, the
material was exposed to the light at 600 mJ/cm.sup.2 from the side
of the transparent substrate (glass plate), and an unexposed part
of the color modulating layer was removed by developing with a 2.38
wt. % aqueous solution of tetramethylammonium hydroxide (TMAH).
[0385] Then the sample was baked at 200.degree. C. to form a
pattern (color modulating layer C) of a fluorescent layer. The
thickness of color modulating layer C was 6.5 .mu.m. The refractive
index of the fluorescent layer A was 1.52 at 589 nm.
[0386] A substrate that was composed of a color modulating member
that satisfies the relation T1>T2, in which a shading layer and
color modulating layers were plane and discretely placed.
[0387] A vary small part of the shading layer and the color
modulating layers was mechanically scraped in order to observe the
luminescence brightness and chromaticity of the organic EL element
to overlay later.
[0388] Then on this substrate, acrylate-based heat-hardening resin
(Nippon Steel Chem. Co. V259PA) was spin-coated as a transparent
medium, and baked at 80.degree. C. The sample was further baked at
160.degree. C. The refractive index of this transparent medium was
1.50 at 589 nm.
[0389] In addition, as a protective coat for the transparent
medium, silicon oxide (SiO.sub.2) was sputtered on the transparent
medium obtained at a substrate temperature of 160.degree. C. at
1.times.10.sup.-6 torr. The thickness of the silicon oxide was 0.5
.mu.m.
[0390] The overall thickness on the shading layer in the
transparent medium prepared as described above was ca. 10 .mu.m
(corresponding to d1), and the relation d2>d1 was satisfied. The
relation .vertline.n1-n2.vertline.<0.4 was also satisfied
judging from refractive indexes of the kinds of the resins
used.
[0391] Next, an organic EL element was prepared in a way similar to
Example 1. Then, an organic EL element display as shown in FIGS. 2a
and 3b was prepared using said organic EL element.
[0392] When a direct current voltage of 8 V was applied between the
anode and the cathode of the organic EL display obtained, a part
(dot pattern S1 of 250 .mu.m.times.600 .mu.m), where the anode and
the cathode crosses, luminesced. The luminescence brightness of the
organic EL element, which could be observed from the part where a
shading layer and a modulating layer had been scraped, was 100
cd/m.sup.2, and luminescence of a blue color having the
chromaticity of x=0.16, y=0.24 in CIE chromaticity coordinates (JIS
Z 8701) was observed.
[0393] In addition, the luminescence brightness observed from color
modulating layer C was 60 cd/m.sup.2, and luminescence of a white
color having the chromaticity of x=0.31, y=0.31 was observed.
[0394] By driving the organic EL display device obtained in this
way, luminescence of white light could be obtained. Good display
without blot or fuzziness was possible without loosing
clearness.
EXAMPLES 12-15
[0395] The relation between the surface roughness
.vertline.T1-T2.vertline- . of the color modulating member and
occurrence of cross talk was surveyed. First, four glass substrates
(Corning 7059, 100 mm.times.100 mm.times.1.1 mm thickness) as
supporting substrates were prepared. For each glass substrate, the
color modulating member in Example 11 were spin-coated at various
rotational speed. Thus, color modulating member whose surface
roughness .vertline.T1-T2.vertline. was 0.2 .mu.m (Example 12), 0.5
.mu.m (Example 13), 1.0 .mu.m (Example 14), and 2.0 .mu.m (Example
15) were prepared under the same condition as Example 11.
[0396] Then, a transparent medium and an organic EL element were
serially prepared on the color modulating member obtained in a way
similar to Example 1 to prepare the organic EL display device
according to the present invention.
[0397] Next, frequency of non-luminescing part (defect frequency)
and frequency of cross talk were visually observed by driving the
organic EL display device prepared in a way similar to Example
11.
[0398] The result is summarized in Table 7, resulting that in case
the surface roughness value .vertline.T1-T2.vertline. is equal to
or smaller than 2.0 .mu.m, defect frequency and frequency of cross
talk were rare (lower than 30% of overall display area).
EXAMPLE 16
[0399] An organic EL display device whose shading layer was
inverted. -trapezoidal was prepared. On a glass substrate (Corning
7059, 100 mm.times.100 mm.times.1.1 mm thick) as a supporting
substrate, acrylate-based light-hardening resist V259PA (Nippon
Steel Chem. Co.) in which 3 wt. % (on a solid basis) carbon black
was dispersed was spin-coated, and baked at 80.degree. C. Then the
resist coat was exposed to the light by an exposing machine having
a mercury lamp as a light source.
[0400] Then the sample was exposed at 750 mJ/cm.sup.2 at 365 nm
through a mask by which a pattern of a grating shading layer shown
in FIG. 11 was obtained.
[0401] Then development was carried out using a 1 wt. % aqueous
solution of sodium carbonate for 3 min at room temperature. Then
overall exposure was carried out from the glass side at 3000
mJ/cm.sup.2, and baked at 200.degree. C. to form a pattern of the
shading layer.
[0402] The thickness of the shading layer obtained was 20 .mu.m. A
scanning electron microscopic (SEM) observation revealed that the
cross-section is a inverted.-trapezoid having a line width of 30
.mu.m (transparent medium side: 50 .mu.m).
[0403] An organic EL display device shown in FIG. 9b was
constructed by preparing a color modulating layer, a transparent
medium, and an organic EL element under the same condition as
Example 1.
[0404] Luminescence of an intrinsic color was obtained from each
color modulating layer in this organic EL display device, and value
of each viewing angle that is defined as a range in which
color-change (color-mixing) does not occur was .+-.80.degree.,
which is a level that does not cause any practical problem. In
addition, as the opening of the organic EL display device was
enlarged, the overall brightness increased and a visual-check
property was improved.
EXAMPLE 17
[0405] An organic EL display device in which a reflection part (Al)
was placed on the side surface of a shading layer was prepared. A
patterned shading layer was formed under the same condition as
Example 1. A 10 wt. % aqueous solution of polyvinylalcohol was
spin-coated all over the substrate, and the sample was baked at
80.degree. C. SEM observation revealed that almost no
polyvinylalcohol coat was attached to the side surface of the
shading layer.
[0406] Then aluminum was deposited, with the substrate spinning,
aiming at the side surface of the shading layer pattern, from an
inclined direction to the substrate at a vacuum of
5.times.10.sup.-7 torr at room temperature. SEM observation
revealed that an aluminium coat was attached (overlaid) to the side
surface of the shading layer. Spectroscopic analysis revealed that
the reflection coefficient of the aluminium coat was equal to or
higher than 10% at 400-700 nm.
[0407] An aluminium coat that attached to an unnecessary part was
lifted off by washing with water together with a polyvinylalcohol
coat.
[0408] A color modulating layer, a transparent medium, and an
organic EL element were prepared under the same condition as
Example 1 to construct the organic EL display device shown in FIG.
10b.
[0409] When a direct current voltage of 8 V was applied between the
anode and the cathode of the organic EL display obtained, a part
where the anode and the cathode crosses, luminesced. The
luminescence brightness of the organic EL element, which could be
observed from the part where a shading layer and a modulating layer
had been scraped, was 100 cd/m.sup.2, and luminescence of a blue
color having the chromaticity of x=0.16, y=0.24 in CIE chromaticity
coordinates (JIS Z 8701) was observed.
[0410] In addition, the luminescence brightness of the light
observed from the blue color filter was 46 cd/m.sup.2, and
luminescence of a blue color having a high color purity and
chromaticity of x=0.14, y=0.12 was obtained.
[0411] In addition, the luminescence brightness of the light
observed from the fluorescent layer A was 130 cd/m.sup.2, and
luminescence of a yellowish green color having the chromaticity of
x=0.28, y=0.62 was obtained.
[0412] In addition, the luminescence brightness of the light
observed from the fluorescent layer B was 33 cd/m.sup.2, and
luminescence of a red color having the chromaticity of x=0.60,
y=0.31 was obtained.
[0413] Brightness observed from color modulating layers was
enhanced with the reflection coefficient on the side surface of the
shading layer being higher than 10%. Luminescence of a desired
intrinsic color from each color modulating layer was obtained, and
value of each viewing angle that is defined as a range in which
color-change (color-mixing) does not occur was .+-.80.degree.,
which is a level that does not cause any practical problem.
EXAMPLE 18
[0414] An organic EL display device whose shading layer was
inverted.-trapezoidal and in which a reflection part (Al) was
placed on the side surface of the shading layer was prepared.
First, a patterned shading layer was formed under the same
condition as Example 16. Then, a 10 wt. % aqueous solution of
polyvinylalcohol was spin-coated all over the substrate, and baked
at 80.degree. C. SEM observation of the cross-section revealed that
almost no polyvinylalcohol coat was attached to the reversely
tapered side surface of the shading layer.
[0415] Then aluminium was deposited, with the substrate spinning,
aiming at the reversely tapered side surface of the shading layer
pattern, from an inclined direction to the substrate at a vacuum of
5.times.10.sup.-7 torr at room temperature. SEM observation
revealed that an aluminium coat was attached (overlaid) to the side
surface of the shading layer. Spectroscopic analysis revealed that
the reflection coefficient of the aluminium coat was equal to or
higher than 10% at 400-700 nm.
[0416] An aluminium coat that attached to an unnecessary part was
lifted off by washing with water together with a polyvinylalcohol
coat.
[0417] A color modulating layer, a transparent medium, and an
organic EL element were prepared under the same condition as
Example 1 to construct the organic EL display device shown in FIG.
10c.
[0418] When a direct current voltage of 8 V was applied between the
anode and the cathode of the organic EL display obtained, a part
where the anode and the cathode crosses, luminesced. The
luminescence brightness of the organic EL element, which could be
observed from the part where a shading layer and a modulating layer
had been scraped, was 100 cd/m.sup.2, and luminescence of a blue
color having the chromaticity of x=0.16, y=0.24 in CIE chromaticity
coordinates (JIS Z 8701) was obtained.
[0419] In addition, the luminescence brightness of the light
observed from the blue color filter was 50 cd/m.sup.2, and
luminescence of a pure blue color having the chromaticity of
x=0.14, y=0.12 was obtained.
[0420] In addition, the luminescence brightness of the light
observed from the fluorescent layer A was 140 cd/m.sup.2, and
luminescence of a yellowish green color having the chromaticity of
x=0.28, y=0.62 was obtained.
[0421] In addition, the luminescence brightness observed from the
fluorescent layer B was 36 cd/m.sup.2, and luminescence of a red
color having the chromaticity of x=0.60, y=0.31 was obtained.
[0422] Brightness observed from a color modulating layer was
enhanced with the reflection coefficient on the side surface of the
shading layer being equal to or higher than 10%. Luminescence of a
desired intrinsic color from each color modulating layer was
obtained, and value of each viewing angle that is defined as a
range in which color-change (color-mixing) does not occur was
.+-.80.degree., which is a level that does not cause any practical
problem. In addition, as the opening of the organic EL display
device was enlarged, the overall brightness increased and a
visual-check property was improved.
EXAMPLE 19
[0423] An organic EL display device in which a reflection part (Al)
was placed on the side surface of a shading layer was prepared. A
patterned shading layer was formed under the same condition as
Example 1 except that aluminium powder was used instead of carbon
black.
[0424] The thickness of the shading layer obtained was 20 .mu.m.
Scanning electron microscopic (SEM) observation revealed that the
cross-section is nearly rectangular. Spectroscopic analysis
revealed that the transmittance of the shading layer is lower than
10%, and the reflection coefficient was equal to or higher than 10%
at 400-700 nm.
[0425] A color modulating layer, a transparent medium, and an
organic EL element were prepared under the same condition as
Example 1 to construct the organic EL display device shown in FIG.
10b.
[0426] When a direct current voltage of 8 V was applied between the
anode and the cathode of the organic EL display obtained, a part
where the anode and the cathode crosses, luminesced. The
luminescence brightness of the organic EL element, which could be
observed from the part where a shading layer and a modulating layer
had been scraped, was 100 cd/m.sup.2, and luminescence of a blue
color having the chromaticity of x=0.16, y=0.24 in CIE chromaticity
coordinates (JIS Z 8701) was obtained.
[0427] In addition, the luminescence brightness of the light
observed from the blue color filter was 45 cd/m.sup.2, and
luminescence of a blue color having a higher color purity and
chromaticity of x=0.14, y=0.12 was obtained.
[0428] In addition, the luminescence brightness of the light
observed from the fluorescent layer A was 125 cd/m.sup.2, and
luminescence of a yellowish green color having the chromaticity of
x=0.28, y=0.62 was obtained.
[0429] In addition, the luminescence brightness the light observed
from the fluorescent layer B was 32 cd/m.sup.2, and luminescence of
a red color having the chromaticity of x=0.60, y=0.31 was
obtained.
[0430] Thus, brightness observed from color modulating layers was
enhanced, with the reflection coefficient on the side surface of
the shading layer being equal to or higher than 10%. Luminescence
of a desired intrinsic color from each color modulating layer was
obtained, and value of each viewing angle that is defined as a
range in which color-change (color-mixing) does not occur was
.+-.80.degree., which is a level that does not cause any practical
problem.
EXAMPLE 20
[0431] An organic EL display device whose shading layer was
inverted. -trapezoidal and in which a reflection part (Al) was
placed on the side surface of a shading layer was prepared. First,
a patterned shading layer was formed under the same condition as
Example 16, except that aluminum powder was used instead of carbon
black.
[0432] The thickness of the shading layer obtained was 20 .mu.m.
Scanning electron microscopic (SEM) observation revealed that the
cross-section was a inverted. -trapezoid having a line width of 30
.mu.m (transparent medium side: 50 .mu.m). Spectroscopic analysis
revealed that the transmittance of the shading layer is equal to or
lower than 10%, and reflection coefficient was equal to or higher
than 10%, at 400-700 nm.
[0433] A color modulating layer, a transparent medium, and an
organic EL element were prepared under the same condition as
Example 1 to construct the organic EL display device shown in FIG.
10c.
[0434] When a direct current voltage of 8 V was applied between the
anode and the cathode of the organic EL display obtained, a part
where the anode and the cathode crosses, luminesced. The
luminescence brightness of the organic EL element, which could be
observed from the part where a shading layer and a modulating layer
had been scraped, was 100 cd/m.sup.2, and luminescence of a blue
color having the chromaticity of x=0.16, y-0.24 in CIE chromaticity
coordinates (JIS Z 8701) was obtained.
[0435] In addition, the luminescence brightness of the light
observed from the blue color filter was 49 cd/m.sup.2, and
luminescence of a blue color having a higher color purity and
chromaticity of x=0.14, y=0.12 was obtained.
[0436] In addition, the luminescence brightness of the light
observed from the fluorescent layer A was 135 cd/m.sup.2, and
luminescence of a yellowish green color having the chromaticity of
x=0.28, y=0.62 was obtained.
[0437] In addition, the luminescence brightness of the light
observed from the fluorescent layer B was 35 cd/m.sup.2, and
luminescence of a red color having the chromaticity of x=0.60,
y=0.31 was obtained.
[0438] Thus, brightness observed from color modulating layers was
enhanced, with the reflection coefficient on the side surface of
the shading layer being equal to or higher than 10%. Luminescence
of a desired intrinsic color from each color modulating layer was
obtained, and value of each viewing angle that is defined as a
range in which color-change (color-mixing) does not occur was
.+-.80.degree., which is a level that does not cause any practical
problem. In addition, as the opening of the organic EL display
device was enlarged, the overall brightness increased and a
visual-check property was improved.
EXAMPLE 21
[0439] An organic EL display device whose shading layer was
inverted.-trapezoidal and in which a reflection part (TiO.sub.2)
was placed on the side surface of a shading layer was prepared.
First, a patterned shading layer was formed under the same
condition as Example 16, except that titanium oxide (TiO.sub.2)
powder was used instead of carbon black.
[0440] The thickness of the shading layer obtained was 20 .mu.m.
Scanning electron microscopic (SEM) observation revealed that the
cross-section was a inverted. -trapezoid having a line width of 30
.mu.m (transparent medium side: 50 .mu.m). Spectroscopic analysis
revealed that a transmittance of this shading layer was lower than
10%, and the reflection coefficient of the aluminium coat was equal
to or higher than 10%, at 400-700 nm.
[0441] A color modulating layer, a transparent medium, and an
organic EL element were prepared under the same condition as
Example 1 to construct the organic EL display device shown in FIG.
10c.
[0442] When a direct current voltage of 8 V was applied between the
anode and the cathode of the organic EL display obtained, a part
where the anode and the cathode crosses, luminesced. The
luminescence brightness of the organic EL element, which could be
observed from the part where a shading layer and a modulating layer
had been scraped, was 100 cd/m.sup.2, and luminescence of a blue
color having the chromaticity of x=0.16, y=0.24 in CIE chromaticity
coordinates (JIS Z 8701) was obtained.
[0443] In addition, the luminescence brightness of the light
observed from the blue color filter was 48 cd/m.sup.2, and
luminescence of a blue color having a higher color purity and
chromaticity of x=0.14, y=0.12 was obtained.
[0444] In addition, the luminescence brightness of the light
observed from the fluorescent layer A was 133 cd/m.sup.2, and
luminescence of a yellowish green color having the chromaticity of
x=0.28, y=0.62 was obtained.
[0445] In addition, the luminescence brightness of the light
observed from the fluorescent layer B was 35 cd/m.sup.2, and
luminescence of a red color having the chromaticity of x=0.60,
y=0.31 was obtained.
[0446] Thus, brightness observed from color modulating layers was
enhanced with the reflection coefficient on the side surface of the
shading layer being equal to or higher than 10%. Luminescence of a
desired intrinsic color from each color modulating layer was
obtained, and value of each viewing angle that is defined as a
range in which color-change (color-mixing) does not occur was
.+-.80.degree., which is a level that does not cause any practical
problem. In addition, as the opening of the organic EL display
device was enlarged, the overall brightness increased and a
visual-check property was improved.
COMPARATIVE EXAMPLES 1-3
[0447] An organic EL display device was constructed under the same
condition as Example 1, except that the relation between d2 and d1,
the relation between T1 and T2, and the relation between S1 and S2
were changed to those shown in Table 5. In Comparative Example 1,
an organic EL display device having relations d2 (50 .mu.m)<d1
(100 .mu.m), T1=T2, and S1=S2 was constructed. In Comparative
Example 2, an organic EL display device having relations d2 (50
.mu.m)<d1 (70 .mu.m), T1<T2, and S1=S2 was constructed.
[0448] In Comparative Example 3, an organic EL display device
having relations d2 (50 .mu.m)<d1 (60 .mu.m), T1=T2, and
S1>S2 was constructed.
[0449] An organic EL display device constructed as described -in
Comparative Example 1 is shown in FIGS. 2b and 3a.
[0450] An organic EL display device constructed as described in
Comparative Example 2 is shown in FIGS. 2b and 5a.
[0451] An organic EL display device constructed as described in
Comparative Example 3 is shown in FIGS. 2b and 7a.
[0452] The result of viewing angles measured with respect to each
organic EL display device are summarized in Table 5. As one can
easily understand the result, color-mixing was observed with
respect to these organic EL display devices. Concerning X and Y
values in CIE chromaticity coordinates, a difference higher than
0.02 was generated. Viewing angle that is defined as a range in
which color-change (color-mixing) does not occur in these organic
EL display devices were considerably narrow (.+-.30.degree. to
.+-.40.degree.).
COMPARATIVE EXAMPLE 4
[0453] An organic EL element device having a transmittance of a
shading layer higher than 10% in Example 1 was constructed. On a
glass substrate (Corning 7059, 100 mm.times.100 mm.times.1.1 mm
thick) as a supporting substrate, acrylate-based light-hardening
resist V259PA (Nippon Steel Chem. Co.) in which 1 wt. % (on a solid
basis) carbon black was dispersed was spin-coated, and baked at
80.degree. C. Then the resist coat was exposed to the light by an
exposing machine having a mercury lamp as a light source.
[0454] Then the sample was exposed at 900 mJ/cm.sup.2 at 365 nm
through a mask by which a pattern of a grating shading layer shown
in FIG. 11 was obtained.
[0455] Then development was carried out using a 1 wt. % aqueous
solution of sodium carbonate for 2 min at room temperature. Then
overall exposure was carried out from the glass side at 3000
mJ/cm.sup.2, and baked at 200.degree. C. to form a pattern of the
shading layer.
[0456] The thickness of the shading layer obtained was 20 .mu.m.
Scanning electron microscopic (SEM) observation revealed that the
cross-section was rectangular. Spectroscopic analysis revealed that
a transmittance of this shading layer was lower than 10%, and the
reflection coefficient was 5%, at 400-700 nm.
[0457] A color modulating layer, a transparent medium, and an
organic EL element were prepared under the same condition as
Example 1 to construct the organic EL display device.
[0458] When a direct current voltage of 8 V was applied between the
anode and the cathode of the organic EL display obtained, a part
where the anode and the cathode crosses, luminesced. The
luminescence brightness of the organic EL element, which could be
observed from the part where a shading layer and a modulating layer
had been scraped, was 100 cd/m.sup.2, and luminescence of a blue
color having the chromaticity of x=0.16, y=0.24 in CIE chromaticity
coordinates (JIS Z 8701) was obtained.
[0459] In addition, the luminescence brightness of the light
observed from the blue color filter was 45 cd/m.sup.2, and
luminescence of a blue color having the chromaticity of x=0.20,
y=0.21 was obtained.
[0460] In addition, the luminescence brightness of the light
observed from the fluorescent layer A was 130 cd/m.sup.2, and
luminescence of a yellowish green color having the chromaticity of
x=0.30, y=0.50 was obtained.
[0461] In addition, the luminescence brightness of the light
observed from the fluorescent layer B was 36 cd/m.sup.2, and
luminescence of a pink color having the chromaticity of x=0.50,
y=0.32 was obtained.
[0462] Thus, as transmittance of the shading layer exceed 10%, and
a shading property of the organic EL display device or color
modulating layers was not enough, the light from each color
modulating layer was remarkably mixed. In addition, the
chromaticity was shifted to white (x=0.32, y=0.31), and the color
purity was remarkably lowered. Therefore, the preferred
transmittance of a shading layer in the organic EL display device
is 10% or lower.
COMPARATIVE EXAMPLE 5
[0463] The relation between (1) the absolute value of the
difference of refractive index n1 of the transparent medium and
refractive index n2 of the color modulating layer and (2) the
luminescence brightness was surveyed. An organic EL display device
was constructed under the same condition as Example 5, except that
nitrogen was used as a transparent medium, wherein refractive index
of nitrogen is 1.00 at 589 nm.
[0464] When a direct current voltage of 8 V was applied between the
anode and the cathode of the organic EL display obtained, a part
where the anode and the cathode crosses, luminesced. The
luminescence brightness of the organic EL element, which could be
observed from the part where a shading layer and a modulating layer
had been scraped, was 100 cd/m.sup.2, and luminescence of a blue
color having the chromaticity of x=0.16, y=0.24 in CIE chromaticity
coordinates (JIS Z 8701) was obtained.
[0465] In addition, the luminescence brightness of the light
observed from the blue color filter was 34 cd/m.sup.2, and
luminescence of a blue color having the chromaticity of x=0.14,
y=0.12 was obtained.
[0466] In addition, the luminescence brightness of the light
observed from the fluorescent layer A was 100 cd/m.sup.2, and
luminescence of a yellowish green color having the chromaticity of
x=0.28, y=0.62 was obtained.
[0467] In addition, the luminescence brightness of the light
observed from the fluorescent layer B was 24 cd/m.sup.2, and
luminescence of a pink color having the chromaticity of x=0.60,
y=0.31 was obtained.
[0468] Thus, as the absolute value of the difference of refractive
index n1 of the transparent medium and refractive index n2 of the
color modulating layer is higher than 0.4
(.vertline.n1-n2.vertline.>0.4), the reflection of luminescence
of the organic EL display device at color modulating layer
interfaces is large, and entrance of the light into color
modulating layers tends to be lost. Therefore, luminescence
brightness from color modulating layers in the organic EL display
device as constructed in this way was lowered.
[0469] The relation between the absolute value of the difference of
refractive index n1 of the transparent medium and refractive index
n2 of the color modulating layer .vertline.n1-n2.vertline. and the
luminescence brightness is summarized in Table 6 (Examples. 1, 4,
5, and Comparative Example 5).
6 TABLE 6 Luminescence brightness of color modulating layers
(cd/m.sup.2) Fluore Fluore .vertline.n1- Blue scent scent n1 n2
n2.vertline. filter layer A layer B Example 1.50 1.50 0-0.02 42 120
30 1 1.52 Example 1.52 1.50 0-0.02 42 120 30 2 1.52 Example 1.30
1.50 0.2- 40 110 28 5 1.52 0.22 Compar- 1.00 1.50 0.5- 34 100 24
ative 1.52 0.52 Example 5
[0470] As one can easily understand from Table 6, as the
.vertline.n1-n2.vertline. value becomes large, the luminescence
brightness tends to become small. Particularly, in case the
.vertline.n1-n2.vertline. value is larger than 0.4, the decrease in
the luminescence brightness is remarkable. Therefore, the absolute
value of the difference of refractive index n1 of the transparent
medium and refractive index n2 of the color modulating layer is
preferably smaller than 0.4.
COMPARATIVE EXAMPLES 6-8
[0471] The relation between the surface roughness
.vertline.T1-T2.vertline- . of color modulating member and the
defect of the organic EL display device, and the relation between
said roughness and occurrence of cross talk were surveyed. First,
three glass substrates (Corning 7059, 100 mm.times.100 mm.times.1.1
mm thickness) for supporting substrates were prepared. The color
modulating member in Example 1 were spin-coating at various
rotational speed. Thus, color modulating member whose surface
roughness .vertline.T1-T2.vertline. was 3.0 .mu.m (Comparative
Example 6), 4.0 .mu.m (Comparative Example 7), and 5.0 .mu.m
(Comparative Example 8) were prepared.
[0472] Then, transparent media and organic EL elements were
serially prepared on the color modulating member obtained, in a way
similar to Example 1, to prepare the organic EL display device
according to the present invention.
[0473] Next, frequency of non-luminescing part (defect frequency)
and frequency of cross talk were visually observed by driving the
organic EL display device in a way similar to Examples 7-10. The
result is summarized in Table 7.
[0474] This result revealed that in case the surface roughness
value .vertline.T1-T2.vertline. of color modulating member is
larger than 2.0 .mu.m, defect frequency and frequency of cross talk
tend to increase (higher than 30% of overall display area).
7 TABLE 7 Frequency of Frequency of .vertline.T1-T2.vertline.
Defect cross talk Example 7 0.2 .mu.m Rare Rare Example 8 0.5 .mu.m
Rare Rare Example 9 1.0 .mu.m Rare Rare Example 10 2.0 .mu.m Rare
Rare Comparative 3.0 .mu.m Frequent Frequent Example 6 Comparative
4.0 .mu.m Frequent Frequent Example 7 Comparative 5.0 .mu.m
Frequent Frequent Example 8
COMPARATIVE EXAMPLE 9
[0475] An organic EL display device was constructed as described in
FIGS. 2b and 3a under the same condition as Example 11, except d1
value was 110 .mu.m, d2 value was 50 .mu.m, and a glass plate
(borosilicate glass) having a thickness of 0.1 mm was attached as a
transparent medium using a transparent adhesive. When the organic
EL display device constructed was driven, blot and fuzziness of
display were observed as shown in Table 5, and good display was not
given.
[0476] Industrial Applicability
[0477] The organic electroluminescence display device as described
above, in which (1) color modulating member containing shading
layers and color modulating layers and (2) organic EL
electroluminescent members containing organic EL elements are
placed sandwiching a transparent medium, wherein the relation
d2.gtoreq.d1 is satisfied, with d1 being a distance between a color
modulating member and an organic EL electroluminescent member, and
d2 being a width of a shading layer, which provides a excellent
viewing angle property and prevents occurrence of color-shift
(color mixing) and blot, is useful as a practical organic EL
display device having an excellent visuality.
* * * * *