U.S. patent application number 10/205010 was filed with the patent office on 2003-02-13 for liquid crystal device board, liquid crystal device, and electronic apparatus.
Invention is credited to Takizawa, Keiji, Tsuyuki, Tadashi.
Application Number | 20030030767 10/205010 |
Document ID | / |
Family ID | 26619373 |
Filed Date | 2003-02-13 |
United States Patent
Application |
20030030767 |
Kind Code |
A1 |
Takizawa, Keiji ; et
al. |
February 13, 2003 |
Liquid crystal device board, liquid crystal device, and electronic
apparatus
Abstract
A first substrate 211 has reflective layer 212 formed thereon,
and the reflective layer 212 has one aperture 212a formed therein
at each pixel. The reflective layer 212 has coloring layers 214
formed thereon, and the coloring layers 214 have an overcoat layer
215 formed thereon. The overcoat layer 215 has apertures 215a
directly above the corresponding apertures 212a. Liquid crystal 232
lies in surface depressions 210a formed so as to correspond to the
apertures 215a of the overcoat layer 215 and is thick above the
apertures 212a of the reflective layer 212.
Inventors: |
Takizawa, Keiji;
(Nagano-ken, JP) ; Tsuyuki, Tadashi; (Nagano-ken,
JP) |
Correspondence
Address: |
HARNESS, DICKEY & PIERCE, P.L.C.
P.O. BOX 828
BLOOMFIELD HILLS
MI
48303
US
|
Family ID: |
26619373 |
Appl. No.: |
10/205010 |
Filed: |
July 25, 2002 |
Current U.S.
Class: |
349/113 ;
349/106 |
Current CPC
Class: |
G02F 1/133555 20130101;
G02F 1/133371 20130101 |
Class at
Publication: |
349/113 ;
349/106 |
International
Class: |
G02F 001/1335 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 26, 2001 |
JP |
2001-226769 |
Jun 27, 2002 |
JP |
2002-188598 |
Claims
1. A liquid crystal device board comprising: at least one
substrate; a reflective layer disposed on the substrate and
including apertures; coloring layers disposed on the reflective
layer; and a substantially transmissive protection layer disposed
on the coloring layers and including at least one of apertures and
thin portions, wherein the apertures or the thin portions of the
protection layer overlap the apertures of the reflective layer, and
wherein the protection layer includes depressions on the surface
thereof, the depressions being formed by the apertures or the thin
portions of the protection layer.
2. The liquid crystal device board according to claim 1, further
comprising an alignment film disposed on the protection layer and
including depressions on the surface thereof.
3. The liquid crystal device board according to claim 1, wherein
the substrate includes depressions on the surface thereof, and the
apertures of the reflective layer lie above the depressions of the
substrate.
4. The liquid crystal device board according to claim 3, wherein
the coloring layers include depressions on the surface thereof, the
depressions of the coloring layers corresponding to the depressions
of the substrate.
5. The liquid crystal device board according to claim 1, further
comprising an underlying layer disposed on the substrate and
including at least one of apertures and thin portions, wherein the
apertures of the reflective layer lie above the apertures or the
thin portions of the underlying layer, and the coloring layers are
disposed on the reflective layer and include depressions on the
surfaces thereof, the depressions of the coloring layers
corresponding to the apertures or the thin portions of the
underlying layer.
6. A liquid crystal device comprising: a liquid crystal layer;
coloring layers; at least one reflective layer including apertures
and reflectors for reflecting light passing through the liquid
crystal layer and the coloring layers; a substantially-transmissive
protection layer covering the coloring layers, wherein the
protection layer includes at least one of apertures and thin
portions which overlap the apertures of the reflective layer, and
wherein the liquid crystal layer lies in depressions formed by the
apertures or the thin portions of the protection layer.
7. A liquid crystal device comprising: a pair of substrates; a
liquid crystal layer disposed between the pair of substrates; at
least one reflective layer disposed on one of the substrates and
including apertures and reflectors for reflecting light passing
through the liquid crystal layer; coloring layers disposed on the
reflective layer; and a substantially-transmissive protection layer
covering the coloring layers and including at least one of
apertures and thin portions which overlap the apertures of the
reflective layer, wherein the liquid crystal layer lies in
depressions formed by the apertures or the thin portions of the
protection layer.
8. A liquid crystal device comprising: a pair of substrates; a
liquid crystal layer disposed between the pair of substrates; at
least one reflective layer disposed on one of the substrates and
including apertures and reflectors for reflecting light passing
through the liquid crystal layer; coloring layers disposed on the
other substrate; and a substantially-transmissive protection layer
covering the coloring layers and including at least one of
apertures and thin portions which overlap the apertures of the
reflective layer, wherein the liquid crystal layer lies in
depressions formed by the apertures or the thin portions of the
protection layer.
9. The liquid crystal device according to claim 6, wherein, when a
is a thickness of the liquid crystal layer in regions which overlap
the reflectors of the reflective layer and b is another thickness
of the liquid crystal layer in other regions which overlap the
apertures of the reflective layer, b is greater than a and equal to
or less than 2a.
10. The liquid crystal device according to claim 9, wherein the
liquid crystal layer comprises nematic liquid crystal having a
predetermined twist angle Tw and satisfies the following
conditions: (1) when 70<Tw.ltoreq.90, a<b.ltoreq.a+1.0 .mu.m,
(2) when 50<Tw.ltoreq.70, a<b.ltoreq.a+2.2 .mu.m, (3) when
30<Tw.ltoreq.50, a<b.ltoreq.a+3.5 .mu.m, and (4) when
0<Tw.ltoreq.30, a<b.ltoreq.a+5.0 .mu.m.
11. The liquid crystal device according to claim 8, wherein at
least one of the pair of substrates comprises depressions on the
surface thereof, and the apertures of the reflective layer lie
above the depressions of the substrate.
12. The liquid crystal device according to claims 11, wherein the
coloring layers comprise thicker portions on the depressions of the
substrate than on other parts of the substrate.
13. The liquid crystal device according to claim 8, wherein at
least one of the pair of substrates includes an underlying layer on
the surface thereof, and the underlying layer includes at least one
of apertures and substantially-transmissive thin portions which
overlap the apertures of the reflective layer.
14. The liquid crystal device according to claims 13, wherein the
coloring layers comprise thicker portions on the apertures or the
thin portions of the underlying layer than on other parts of the
underlying layer.
15. The liquid crystal device according to claim 8, further
comprising a substantially transmissive light-transmitting layer
disposed on the reflective layer and including at least one of
apertures and thin portions which overlap the apertures of the
reflective layer.
16. The liquid crystal device according to claim 15, wherein the
coloring layers comprise thicker portions on the apertures or the
thin portions of the light-transmitting layer than on other parts
of the light-transmitting layer.
17. The liquid crystal device according to claim 6, further
comprising: an observation-side retardation film; an
observation-side polarizer; a rear-side retardation film; and a
rear-side polarizer, wherein the observation-side retardation film
and polarizer are disposed opposite to the reflective layer with
respect to the liquid crystal layer, and the rear-side retardation
film and polarizer are disposed opposite to the liquid crystal
layer with respect to the reflective layer.
18. An electronic apparatus comprising: the liquid crystal device
according to claim 6; and control means for controlling the liquid
crystal device.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Technical Field of the Invention
[0002] The present invention relates to a liquid crystal device
board, a liquid crystal device, and an electronic apparatus, and
more particularly, the present invention relates to a structure
suitable for a transflective liquid crystal device.
[0003] 2. Description of the Related Art
[0004] Hitherto, in known transflective liquid crystal display
panels, both reflective display using external light and
transmissive display using illuminating light such as backlight are
made visible. Each of the transflective liquid crystal display
panels has a reflective layer therein for reflecting external light
and has a structure in which illuminating light such as backlight
passes through the reflective layer. Some reflective layers of this
type have one aperture (one slit) at each pixel of the liquid
crystal display panel having a predetermined area.
[0005] FIG. 16 is a schematic sectional view schematically
illustrating the schematic structure of a known transflective
liquid crystal display panel 100. The liquid crystal display panel
100 has a structure in which a substrate 101 and a substrate 102
are bonded to each other with sealing adhesive 103 and liquid
crystal 104 is infused between the substrates 101 and 102.
[0006] The substrate 101 has a reflective layer 111, having one
aperture 111a at each pixel, formed on the inner surface thereof,
and the reflective layer 111 has a color filter 112, having
coloring layers 112r, 112g, and 112b and an overcoat layer 112p,
formed thereon. The overcoat layer 112p on the color filter 112 has
transparent electrodes 113 formed on the surface thereof.
[0007] On the other hand, the substrate 102 has transparent
electrodes 121 formed on the inner surface thereof so as to
intersect with the transparent electrodes 113 on the substrate 101
which faces the substrate 102. The transparent electrodes 113 above
the substrate 101 and transparent electrodes 121 above the
substrate 102 have an alignment film and a hard protective film
formed thereon as necessary.
[0008] Also, the substrate 102 has a retardation film (1/4 wave
film) 105 and a polarizer 106 sequentially disposed on the outer
surface thereof, and the substrate 101 has a retardation film (1/4
wave film) 107 and a polarizer 108 sequentially disposed on the
outer surface thereof.
[0009] When the liquid crystal display panel 100 having a structure
as described above is installed in an electronic apparatus such a
portable phone or a portable information terminal, the electronic
apparatus has a backlight 109 behind the liquid crystal display
panel 100. In the liquid crystal display panel 100, during the
daytime or in a well-lighted area, e.g., in a building, reflective
display is visible since external light is reflected off the
reflective layer 111 after passing through the liquid crystal 104,
again passes through the liquid crystal 104, and is emitted from
the liquid crystal display panel 100 along a reflecting path R. On
the other hand, at nighttime or in a dark area, e.g., in an open
area, by illuminating the backlight 109, transmissive display is
visible since, after passing through the apertures 111a, a part of
illuminating light from the backlight 109 passes through the liquid
crystal display panel 100 and then is emitted from the liquid
crystal panel 100 along a transmitting path T.
[0010] However, in the known transflective liquid crystal display
panel 100 described above, making the areas of the apertures of the
reflective layer small so as to improve the brightness of the
reflective display causes deteriorated brightness of the
transmissive display. In particular, since transmitting light in
the transmissive display passes through the liquid crystal layer
only once while reflecting light visible in the reflective display
passes through the liquid crystal layer twice, the transflective
liquid crystal display panel 100 can not be optically constructed
such that both reflected light and transmitted light are
effectively used so that the two types of display mentioned above
are clearly visible in the light transmissive state. For example,
since the transflective liquid crystal display panel 100 is often
constructed such that reflected light is effectively emitted from
the liquid crystal display panel in the reflective display which is
likely to become dark, the utilization efficiency of transmitted
light (the ratio of the amount of light passing through and
emitting from the liquid crystal display panel to the amount of
light incident on the liquid crystal display panel) necessary to
achieve the transmissive display is low, and thus the transmissive
display becomes dark when the areas of the apertures of the
reflective layer are excessively reduced as described above.
[0011] Accordingly, it is extremely difficult to construct the
transflective liquid crystal display panel 100 so as to make both
the reflective display and the transmissive display bright, that
is, making the reflective display bright by reducing the areas of
the apertures of the reflective layer requires the amount of
illuminating light from the backlight to be sufficient enough so as
to maintain the brightness of the transmissive display, thereby
hampering the liquid crystal device to achieve a reduction in size,
thickness, weight, and power consumption, which is essential to a
portable electronic apparatus.
[0012] Also, since the brightness in the reflective display is in
general insufficient as described above, the light transmission of
the color filter 112 is required to be high so as to maintain the
sufficiently bright display; however, this arrangement causes a
problem in that sufficient chroma in the transmissive display
obtained by light passing through the color filter only once is not
achieved.
[0013] In view of the foregoing problems, one object of the present
invention is to provide a liquid crystal device having a structure
in which the brightness in reflective display and the brightness in
transmissive display are achieved together in a higher dimension
and in which the brightness in the reflective display and the
chroma in the transmissive display are maintained together.
SUMMARY OF THE INVENTION
[0014] The present invention is made so as to solve the above
described problems. A liquid crystal device board according to the
present invention comprises at least one substrate; a reflective
layer disposed on the substrate and comprising apertures; coloring
layers disposed on the reflective layer; and a substantially
transmissive protection layer disposed on the coloring layers and
comprising apertures or thin portions. The apertures or the thin
portions of the protection layer are disposed in the regions which
overlap the apertures of the reflective layer, and the protection
layer includes depressions on the surface thereof, the depressions
being formed by the apertures or the thin portions of the
protection layer.
[0015] More particularly, the liquid crystal device board according
to the present invention may further comprise an alignment film
disposed on the protection layer and comprising depressions on the
surface thereof.
[0016] According to the present invention, since the apertures or
the thin portions formed in the protection layer disposed on the
coloring layers of the liquid crystal device board allow the
protection layer to have depressions formed on the surface thereof,
when a transflective liquid crystal device is formed with these
surface depressions, portions of liquid crystal above the apertures
of the reflective layer are thicker than the other portions of the
liquid crystal, and, accordingly, the liquid crystal in the regions
above the apertures, which are used for achieving transmissive
display, is thicker than in the other regions above the reflecting
surfaces of the reflective layers, which are used for achieving
reflective display. With this arrangement, since a retardation of
the liquid crystal acting on transmitting light necessary to
achieve the transmissive display (an optical value of the liquid
crystal acting on light passing through the liquid crystal layer)
approaches another retardation of the liquid crystal acting on
reflecting light necessary to achieve the reflective display (an
optical value of the liquid crystal acting on light passing through
the liquid crystal layer twice), the utilization efficiency of the
transmitted light necessary to achieve the transmissive display is
improved. When the utilization efficiency of the transmitted light
is improved, the amount of illuminating light necessary to achieve
the transmissive display can be reduced, and also the reflective
display can be made brighter by reducing the areas of the apertures
of the reflective layer.
[0017] In the liquid crystal device board according to the present
invention, the substrate may comprise depressions on the surface
thereof, and the apertures of the reflective layer may lie above
the depressions. Since the apertures of the reflective layer lie
above the depressions on the surface of the substrate, thick
portions corresponding to the depressions can be formed in the
coloring layers formed on the reflective layer, and thus the chroma
of the transmissive display can be improved. Further, in this case,
the coloring layers may include depressions on the surface thereof,
the depression corresponding to the depressions of the substrate.
Since the depressions corresponding to the depressions on the
surface of the substrate are also formed on the surface of the
coloring layers, the surface depressions formed by the apertures or
the thin portions of the protection layer can be easily made
deeper, the liquid crystal in the regions thereof, which contribute
to the transmissive display, can be made thicker, and thus the
utilization efficiency of the transmitted light necessary to
achieve the transmissive display can be further improved.
[0018] Also, the liquid crystal device board according to the
present invention may further comprise an underlying layer disposed
on the substrate and including apertures or thin portions. The
apertures of the reflective layer lie above the apertures or the
thin portions of the underlying layer and the coloring layers are
disposed on the reflective layer and include depressions on the
surfaces thereof, the depressions corresponding to the apertures or
the thin portions of the underlying layer. With this arrangement,
the underlying layer having the apertures or the thin portions
makes the surface depressions deeper, and thus the utilization
efficiency of the transmitted light necessary to achieve the
transmissive display can be further improved.
[0019] A liquid crystal device according to the present invention
comprises a liquid crystal layer; coloring layers; at least one
reflective layer comprising apertures and reflectors for reflecting
light passing through the liquid crystal layer and the coloring
layers; a substantially-transmissive protection layer covering the
coloring layers. The protection layer includes apertures or thin
portions in the regions which overlap the apertures of the
reflective layer and the liquid crystal layer lies in depressions
formed by the apertures or the thin portions of the protection
layer.
[0020] In the liquid crystal device according to the present
invention, since the liquid crystal layer lies in the depressions
formed by the apertures or the thin portions of the protection
layer, the liquid crystal can be made thick in the regions which
overlap the apertures of the reflective layer, and thus the
brightness of the transmissive display can be improved.
Accordingly, the amount of illuminating light necessary to achieve
the transmissive display can be reduced, and also the reflective
display can be made brighter by reducing the areas of the apertures
of the reflective layer.
[0021] Also, another liquid crystal device according to the present
invention comprises a pair of substrates; a liquid crystal layer
disposed between the pair of substrates; at least one reflective
layer disposed on one of the substrates and including apertures and
reflectors for reflecting light passing through the liquid crystal
layer; coloring layers disposed on the reflective layer; and a
substantially-transmissive protection layer covering the coloring
layers and including apertures or thin portions in the regions
which overlap the apertures of the reflective layer. The liquid
crystal layer lies in depressions formed by the apertures or the
thin portions of the protection layer.
[0022] According also to the present invention, since the liquid
crystal layer lies in the depressions formed by the apertures or
the thin portions of the protection layer, the liquid crystal can
be made thick in the regions which overlap the apertures of the
reflective layer the brightness of the transmissive display can be
improved. Accordingly, the amount of illuminating light necessary
to achieve the transmissive display can be reduced, and also the
reflective display can be made brighter by reducing the areas of
the apertures of the reflective layer.
[0023] Furthermore, another liquid crystal device according to the
present invention comprises a pair of substrates; a liquid crystal
layer disposed between the pair of substrates; at least one
reflective layer disposed on one of the substrates and including
apertures and reflectors for reflecting light passing through the
liquid crystal layer; coloring layers disposed on the other
substrate; and a substantially-transmissive protection layer
covering the coloring layers and including apertures or thin
portions in the regions which overlap the apertures of the
reflective layer. The liquid crystal layer lies in depressions
formed by the apertures or the thin portions of the protection
layer.
[0024] According also to the present invention, since the liquid
crystal layer lies in the depressions formed by the apertures or
the thin portions of the protection layer, the liquid crystal can
be made thick in the regions which overlap the apertures of the
reflective layer, and thus the brightness of the transmissive
display can be improved. Accordingly, the amount of illuminating
light necessary to achieve the transmissive display can be reduced,
and also the reflective display can be made brighter by reducing
the areas of the apertures of the reflective layer.
[0025] In the liquid crystal device according to the present
invention, when "a" is defined as a thickness of the liquid crystal
layer in the regions which overlap the reflectors of the reflective
layer and "b" is defined as another thickness of the liquid crystal
layer in the other regions which overlap the apertures of the
reflective layer, b is preferably greater than a and equal to or
less than 2a.
[0026] In the liquid crystal device according to the present
invention, when the thickness b of the liquid crystal layer in the
regions which overlap the apertures of the reflective layer is
greater than the thickness a of the liquid crystal layer in the
other regions which overlap the reflecting surfaces of the
reflective layer, and equal to or less than 2a, the utilization
efficiency of light necessary to achieve the transmissive display
can be improved.
[0027] In the liquid crystal device according to the present
invention, the liquid crystal layer may comprise nematic liquid
crystal having a predetermined twist angle Tw and may satisfy the
following conditions: (1) when 70<Tw.ltoreq.90,
a<b.ltoreq.a+1.0 [.mu.m], (2) when 50<Tw.ltoreq.70,
a<b.ltoreq.a+2.2 [.mu.m], (3) when 30<Tw.ltoreq.50,
a<b.ltoreq.a+3.5 [.mu.m], and (4) when 0<Tw.ltoreq.30,
a<b.ltoreq.a+5.0 [.mu.m]. In general, when the twist angle Tw is
equal to or less than 90 degrees, compared to the state in which
the thickness b of the liquid crystal layer in the transmissive
regions which overlap the apertures is equal to the thickness a of
the liquid crystal layer in the reflective regions which overlap
the reflecting surfaces, the light transmission can be improved in
the foregoing ranges in which the thickness b of the liquid crystal
layer is greater than the thickness a of the liquid crystal layer.
For example, when the thickness b in the transmissive regions is
optimized with respect to the light transmission for the
transmissive display, the light transmission for the reflective
display in the foregoing ranges can be improved. Also, when the
thickness a in the reflective regions is optimized with respect to
the light transmission for the reflective display, the light
transmission for the transmissive display in the foregoing ranges
can be improved.
[0028] Also, in the liquid crystal device according to the present
invention, at least one of the pair of substrates may include
depressions on the surface thereof, and the apertures of the
reflective layer may lie above the depressions. In particular,
since the liquid crystal device has surface depressions formed
therein, in which the liquid crystal lies, corresponding to the
depressions, the liquid crystal in the regions which overlap the
apertures of the reflective layer can be easily made thicker.
[0029] In this case, at least one of the pair of substrates may
include depressions on the surface thereof, and the apertures of
the reflective layer may lie above the depressions. With this
arrangement, the thick portions of the coloring layers can be
easily formed and also the chroma of the transmissive display can
be improved by disposing the thick portions.
[0030] In addition, in the liquid crystal device according to the
present invention, at least one of the pair of substrates may
comprise an underlying layer on the surface thereof, and the
underlying layer may comprise apertures or
substantially-transmissive thin portions in the regions which
overlap the apertures of the reflective layer. In particular, since
the liquid crystal device has surface depressions formed therein,
in which the liquid crystal lies, corresponding to the apertures or
the thin portions of the underlying layer, the liquid crystal in
the regions which overlap the apertures of the reflective layer can
be easily made thicker. Also, in this case, the coloring layers may
comprise thick portions on the apertures or the thin portions of
the underlying layer.
[0031] Furthermore, the liquid crystal device according to the
present invention may further comprise a substantially transmissive
light-transmitting layer disposed on the reflective layer and
including apertures or thin portions in the regions which overlap
the apertures of the reflective layer. In particular, since the
liquid crystal device has surface depressions formed therein, in
which the liquid crystal lies, corresponding to the apertures or
the thin portions of the light-transmitting layer, the liquid
crystal in the regions which overlap the apertures of the
reflective layer can be easily made thicker. Also, in this case,
the coloring layers may comprise thick portions on the apertures or
the thin portions of the light-transmitting layer.
[0032] The above described liquid crystal device may further
comprise an observation-side retardation film; an observation-side
polarizer; a rear-side retardation film; and a rear-side polarizer,
wherein the observation-side retardation film and polarizer are
disposed opposite to the reflective layer with respect to the
liquid crystal layer, and the rear-side retardation film and
polarizer are disposed opposite to the liquid crystal layer with
respect to the reflective layer.
[0033] An electronic apparatus according to the present invention
comprises any one of the liquid crystal devices described above and
control means for controlling the liquid crystal device. In
particular, the electronic apparatus according to the present
invention is preferably a portable electronic apparatus such as a
portable phone or a portable information terminal.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] FIG. 1 is a schematic perspective view illustrating the
external appearance of a liquid crystal display panel of a first
embodiment of the present invention.
[0035] FIG. 2 includes a schematic sectional view FIG. 2(a)
schematically illustrating the structure of the liquid crystal
display panel of the first embodiment, and a magnified plan view
FIG. 2(b) illustrating the plane structure of a color filter
substrate of the panel.
[0036] FIG. 3 is a magnified sectional view of part of an enlarged
scale schematically illustrating the internal structure of a pixel
of the liquid crystal display panel according to the first
embodiment.
[0037] FIG. 4 is a schematic sectional view schematically
illustrating the internal structure of a pixel of a liquid crystal
device of a second embodiment of the present invention.
[0038] FIG. 5 is a schematic sectional view schematically
illustrating the internal structure of a pixel of a liquid crystal
device of a third embodiment of the present invention.
[0039] FIG. 6 is a schematic sectional view schematically
illustrating the internal structure of a pixel of a liquid crystal
device of a fourth embodiment of the present invention.
[0040] FIG. 7 is a schematic sectional view schematically
illustrating the internal structure of a pixel of a liquid crystal
device of a fifth embodiment of the present invention.
[0041] FIG. 8 is a schematic sectional view schematically
illustrating the internal structure of a pixel of a liquid crystal
device of a sixth embodiment of the present invention.
[0042] FIG. 9 is a schematic sectional view schematically
illustrating the internal structure of a pixel of a liquid crystal
device of a seventh embodiment of the present invention.
[0043] FIG. 10 is a schematic sectional view schematically
illustrating the internal structure of a pixel of a liquid crystal
device of an eighth embodiment of the present invention.
[0044] FIG. 11 includes schematic process charts FIGS. 11(a) to
11(e) of fabrication methods of the liquid crystal device of the
present invention according to fabrication method embodiments of
the present invention.
[0045] FIG. 12 is a schematic view illustrating the display
principle of the liquid crystal device of the present
invention.
[0046] FIG. 13 is a schematic block diagram illustrating the
configuration of an electronic apparatus according to the present
invention.
[0047] FIG. 14 is a perspective view of the external appearance of
a portable phone as an example of the electronic apparatus.
[0048] FIG. 15 is a schematic sectional view schematically
illustrating the main structure of the liquid crystal display panel
according to the first embodiment.
[0049] FIG. 16 is a schematic sectional view schematically
illustrating the structure of the transflective liquid crystal
display panel having a known, conventional, structure.
[0050] FIG. 17 illustrates a magnified sectional view of part of a
color filter substrate as an example and a plan view of a color
filter as an example so as to demonstrate the structure in more
detail.
[0051] FIG. 18 includes FIGS. 18(a), 18(b), and 18(c) illustrating
diagrams of spectral transmittances, xy chromaticity, and a*b*
chromaticity, respectively, of light passing through hyperchromic
portions of the above-mentioned example color filter.
[0052] FIG. 19 includes FIGS. 19(a), 19(b), and 19(c) illustrating
diagrams of spectral transmittances, xy chromaticity, and a*b*
chromaticity, respectively, of light passing through hypochromic
portions of the above-mentioned example color filter.
[0053] FIG. 20 includes FIGS. 20(a) to 20(d) illustrating diagrams
of the relationships between liquid crystal thicknesses b of the
transmitting region and transmittances of the transmitting region
in a transmitting state according to a range of twist angles Tw of
a liquid crystal layer, and also includes FIG. 20(e) illustrating a
diagram of the relationship between the twist angle Tw and the
liquid crystal thickness b for achieving the maximum transmittance
of the transmitting region.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0054] Referring now to the accompanying drawings, the liquid
crystal device board, the liquid crystal device, and the electronic
apparatus according to the present invention will be described in
detail.
[0055] First, a liquid crystal device of a first embodiment of the
present invention will be described with reference to FIGS. 1 and
2.
[0056] FIG. 1 is a schematic perspective view illustrating the
external appearance of a liquid crystal display panel 200 included
in a liquid crystal device of the first embodiment of the present
invention. FIG. 2(a) is a schematic sectional view schematically
illustrating the liquid crystal display panel 200, and FIG. 2(b) is
a magnified plan view of part of a color filter substrate 210
included in the liquid crystal display panel 200.
[0057] The liquid crystal device has an illuminating device (not
shown) such as a backlight or a front light, and a casing (not
shown) in which the liquid crystal display panel 200 mounted having
a so-called transflective-type passive matrix structure, if
required.
[0058] As shown in FIG. 1, the liquid crystal display panel 200 has
a cell structure in which a color filter substrate 210 having a
transparent first substrate 211 as a base, which is made from a
glass plate, a synthetic resin plate, or the like, and a counter
substrate 220 facing the color filter substrate 210 and having a
second substrate 221 as a base, which is similar to the first
substrate 211, are bonded to each other with sealing adhesive 230,
and liquid crystal 232 is infused inside the space formed
therebetween and enclosed by the sealing adhesive 230 via an
opening 230a and is sealed in the space with sealant 231.
[0059] The first substrate 211 has a plurality of strips of
transparent electrodes 216 formed parallel to each other on the
inner surface thereof (on the surface thereof facing the second
substrate 221), and the second substrate 221 has a plurality of
strips of transparent electrodes 222 formed parallel to each other
on the inner surface thereof. Also, the transparent electrodes 216
are electrically connected to wiring lines 218A, and the
transparent electrodes 222 are electrically connected to wiring
lines 228. The transparent electrodes 216 and 222 are orthogonal to
each other. A large number of pixels are configured in a matrix
array in a region where these transparent electrodes intersect with
each other, and these arrayed pixels constitute a liquid crystal
display region A.
[0060] The first substrate 211 has a substrate overhang 210T
extending outward from the external end of the second substrate
221. The wiring lines 218A, wiring lines 218B electrically
connected to the wiring lines 228 via a vertical conductor as part
of the sealing adhesive 230, and an input terminal unit 219 having
a plurality of independently formed wiring patterns is formed on
the substrate overhang 210T. Also, the substrate overhang 210T has
a semiconductor IC 261 including a liquid crystal drive circuit and
so forth so as to be electrically connected to these wiring lines
218A and 218B and the input terminal unit 219 mounted thereon. In
addition, the substrate overhang 210T has a flexible wiring board
263 mounted at the end thereof so as to be electrically connected
to the input terminal unit 219.
[0061] In the liquid crystal display panel 200, as shown in FIGS.
2(a) and 2(b), the first substrate 211 has a retardation film (1/4
wave film) 240 and a polarizer 241 disposed on the outer surface
thereof, and the second substrate 221 has a retardation film (1/4
wave film) 250 and a polarizer 251 disposed on the outer surface
thereof.
[0062] Referring now to FIGS. 2(a) and (b), the structure of the
color filter substrate 210 corresponding to the liquid crystal
device board according to the present invention will be described
in detail. The first substrate 211 has a reflective layer 212
formed on the surface thereof. The reflective layer 212 can be
formed from a metal film made from aluminum, an aluminum alloy,
chromium, a chromium alloy, silver, a silver alloy, or the like.
The reflective layer 212 has a reflector 212r having a reflective
surface and disposed at each pixel mentioned above, and an aperture
212a disposed at each pixel.
[0063] The reflective layer 212 has coloring layers 214 formed
thereon, one at each pixel, and an overcoat layer 215 made from a
transparent resin such as an acrylic resin or an epoxy resin so as
to cover the coloring layers 214. The color filter is configured by
the coloring layers 214 and the overcoat layer 215.
[0064] T coloring layers 214 are designed to provide a
predetermined color usually by dispersing a colorant such as a
pigment or a dye into a transparent resin. As an example of the
colors of the coloring layers, three colors, i.e., R (red), G
(green), and B (blue), of three primary color filters are combined;
however, the colors are not restricted to these and the coloring
layers can have various colors including complimentary colors. The
coloring layers having a predetermined color pattern are generally
formed by applying colored resist, made from a photosensitive resin
containing a colorant such as a pigment or a dye, on the surface of
the substrate, and then by removing unnecessary portions by
photolithography. When coloring layers having a plurality of colors
are formed, the foregoing step is repeated in this stage.
[0065] The coloring layers 214, one formed at each pixel in the
above described manner, have a black matrix film (or black mask
film) 214BM formed in the space between adjacent pixels, i.e.,
between adjacent coloring layers 214. This black matrix film 214BM
is formed, for example, by dispersing a colorant such as a black
pigment or a black dye into a resin or other base material, or by
dispersing three kinds of colorants, R (red), G (green), and B
(blue), all together into a resin or other base material.
[0066] Although the coloring layers are illustrated in a stripe
array in FIG. 2(b) by way of example, the coloring layers may have
various array patterns such as a delta array and a mosaic array,
other than the stripe array.
[0067] The overcoat layer 215 has apertures 215a, one formed at
each pixel, directly above the regions facing the corresponding
apertures 212a of the reflective layer 212 (i.e., the regions which
two-dimensionally overlap the corresponding apertures 212a).
Accordingly, the surfaces of the coloring layers 214 are exposed to
the upper layer on the coloring layers 214 via the apertures 215a
in this embodiment.
[0068] The overcoat layer 215 has transparent electrodes 216 made
from a transparent conductor such as ITO (indium tin oxide)
thereon. The transparent electrodes 216 are formed in strips
extending along the vertical direction viewed in FIG. 2(b), and the
plurality of transparent electrodes 216 are arranged in strips
lying parallel to each other. The transparent electrodes 216 have
an alignment film 217, made from a polyimide resin or the like,
formed thereon.
[0069] The transparent electrodes 216 have depressions 216a formed
on the surfaces of the corresponding apertures 215a formed in the
overcoat layer 215. Although the depressions 216a are covered by
the alignment film 217, the depression profiles thereof are
followed on the surface of the color filter substrate 210, allowing
the color filter substrate 210 to have surface depressions 210a,
one at each pixel.
[0070] On the other hand, the counter substrate 220 facing the
color filter substrate 210 is constructed such that the transparent
electrodes 222 similar to the transparent electrodes 216, a hard
protective film 223 made from SiO.sub.2, TiO.sub.2, or the like,
and an alignment film 224 similar to the alignment film 217 are
sequentially laminated on the second substrate 221 made from glass
or the like.
[0071] As shown in FIG. 3, the liquid crystal 232 is infused
between the color filter substrate 210 and the counter substrate
220 configured in the above described manner. In this case, since
one surface depressions 210a is formed at each pixel on the inner
surface of the color filter substrate 210 in the above described
manner, the liquid crystal 232 is configured so as to fill the
surface depressions 210a (i.e., the apertures 215a of the overcoat
layer 215). With this configuration, the liquid crystal layer is
thicker in the regions where the apertures 215a of the overcoat
layer 215 are formed (that is, in the regions where the apertures
212a of the reflective layer 212 are formed) than in other regions
(that is, in the regions where the reflectors 212r are formed).
[0072] In this embodiment which is configured in the above
described manner, external light incident from the counter
substrate 220 side passes through the liquid crystal 232 and the
color filter, is then reflected off the reflectors 212r, again
passes through the liquid crystal 232 and the counter substrate
220, and exits the liquid crystal panel 200. In this case, the
incoming light passes through the coloring layers 214 of the color
filter twice.
[0073] On the other hand, since the coloring layers 214 cover the
apertures 212a of the reflective layer 212, when a backlight or the
like is disposed behind the color filter substrate 210, for
example, and illuminating light is radiated behind the color filter
substrate 210, a part of the illuminating light passes through the
apertures 212a of the reflective layer 212, passes through the
coloring layers 214, passes through the liquid crystal 232 and the
counter substrate 220, and exits the liquid crystal panel 200. In
this case, the transmitting light passes through the coloring
layers 214 only once.
[0074] In this embodiment, since the overcoat layer 215 of the
color filter, formed on the first substrate 211, has the apertures
215a formed in the regions which overlap the corresponding
apertures 212a of the reflective layer 212, the color filter
substrate 210 is provided with the surface depressions 210a, and
also, since the liquid crystal 232 fills the surface depressions
210a and accordingly the liquid crystal layer is thick in the
regions which overlap the apertures 212a of the reflective layer, a
retardation (=.DELTA.n.times.d: where, .DELTA.n is the refractive
index anisotropy and d is the thickness) of the liquid crystal
layer acting on transmitting light forming the transmissive display
increases, and as a result, the utilization efficiency of the
transmitted light used for the transmissive display is
improved.
[0075] FIG. 12 is a schematic view illustrating the effect of the
thickness of the liquid crystal by changing it in the above
described manner. It is assumed that, by forming a coloring layer C
on a reflective layer R having an aperture Ra therein, by forming a
light-transmitting layer T on the coloring layer C, and by
providing the light-transmitting layer T with an aperture above the
aperture Ra of the reflective layer R in the above described
manner, the thickness b of the liquid crystal is about twice as
large in the region which overlaps the aperture Ra as the thickness
a of the liquid crystal in the other region. Also, for convenience
of explanation, it is assumed that a homogenous liquid crystal cell
is constructed and that retardations of this liquid crystal cell
are given by .DELTA.n.times.a=.lambda./4 and
.DELTA.n.times.b=.lambd- a./2 (where, .DELTA.n is the refractive
index anisotropy of the liquid crystal and .lambda. is wavelength
of light).
[0076] In the above described situation, when the liquid crystal
cell is in a light transmissive state, as illustrated by (a) in
FIG. 12 for transmissive display, illuminating light from a
backlight or the like is converted to linearly polarized light
after passing through a polarizer P2, then is converted to, for
example, right-hand circularly polarized light passing through a
retardation film (1/4 wave film) D2, subsequently is converted to
left-hand circularly polarized light since the phase of the light
further advances by a 1/2 wavelength after passing through the
liquid crystal layer having a cell thickness D2, subsequently
returns to the original linearly polarized light after passing
through a retardation film D1, and then passes through a polarizer
P1.
[0077] Also, when the liquid crystal cell is in a light
transmissive state, as in the above described manner, as
illustrated by (b) in FIG. 12 for reflective display, external
light is converted to linearly polarized light after passing
through the polarizer P1, then is converted to, for example,
right-hand circularly polarized light after passing through the
retardation film (1/4 wave film) D1, subsequently is converted to
left-hand circularly polarized light since the phase further
advances by 1/2 wavelength after passing through the liquid crystal
layer having a cell thickness D1 twice in both directions,
subsequently returns to the original linearly polarized light after
passing through the retardation film D1 again, and then passes
through the polarizer P1.
[0078] In the foregoing transmissive display, when it is assumed
that the thickness of the liquid crystal through which light passes
is tentatively set to "a" (which is half the liquid crystal
thickness "b" illustrated by (a) in FIG. 12), since its retardation
is .lambda./4, as illustrated by (c) in FIG. 12, illuminating light
is converted to linearly polarized light orthogonal to the original
light after passing through the polarizer P2, the retardation film
D2, and the liquid crystal, then is converted to left-hand
circularly polarized light after passing through the retardation
film D1, and then passes through the polarizer P1. In this case,
the quantity of the polarized component of the illuminating light
passing through the polarizer P1 is substantially half that passing
through the polarizer P1 when the thickness of the liquid crystal
is b.
[0079] As described above, in the case of the transflective liquid
crystal display panel according to this embodiment, when the liquid
crystal thickness b in the regions which two-dimensionally overlap
the apertures of the reflective layer is thicker than the liquid
crystal thickness a in the other regions, the light transmission in
a light transmissive state increases. In particular, when the
liquid crystal thickness b in the regions which two-dimensionally
overlap the apertures becomes substantially twice the liquid
crystal thickness a in the other regions, the quantity of
transmitting light becomes substantially double.
[0080] When the liquid crystal cell is not of a homogeneous type
and the liquid crystal layer has a twist angle, the light
transmission sometimes does not increase; however, for example, in
a liquid crystal having a 40-degree twist angle, when the liquid
crystal thickness in the regions which two-dimensionally overlap
the apertures is set to be twice that in the other region, the
light transmission increases by about 40%. In general, the liquid
crystal thickness b in the regions which overlap the apertures of
the reflective layer is preferably greater than the liquid crystal
thickness a above the reflective surface and equal to or less than
2a. With this arrangement, since the utilization efficiency of
transmitted light necessary to achieve the transmissive display
increases, and thus the transmissive display becomes bright, for
example, the amount of illuminating light from the backlight can be
reduced, thus achieving a small, thin, light backlight which
consumes less electric power. Also, the opening area of the
reflective layer can be reduced more than is possible today,
thereby improving the brightness of the reflective display.
[0081] Also, when the liquid crystal layer formed from nematic
liquid crystal has a twist angle Tw, since the relationship between
the liquid crystal thickness a in the reflective regions and the
liquid crystal thickness b in the transmissive regions is
determined depending on the effects of optical rotation caused by
twisted liquid crystal molecules and of birefringence proportional
to the thickness of the liquid crystal layer, the optimal range
varies according to the twist angle Tw in the foregoing range of
a<b.ltoreq.2a. More particularly, the light transmission
increases in the following ranges by making the liquid crystal
thickness b greater than the liquid crystal thickness a:
[0082] when 70<Tw.ltoreq.90, a<b.ltoreq.a+1.0 [.mu.m], (2)
when 50<Tw.ltoreq.70, a<b.ltoreq.a+2.2 [.mu.m], (3) when
30<Tw.ltoreq.50, a<b.ltoreq.a+3.5 [.mu.m], and (4) when
0<Tw.ltoreq.30, a<b.ltoreq.a+5.0 [.mu.m].
[0083] With respect to the foregoing cases (1) to (4), FIGS. 20(a)
to 20(d) illustrate the light transmission in the transmissive
regions when the liquid crystal display panel is in a transmissive
state (e.g., in a state in which an electric field is not applied
in a normally white panel) by changing the liquid crystal thickness
b in the transmissive regions while optimizing the liquid crystal
thickness a in the reflective regions. As can be seen from these
diagrams, in any of the foregoing cases (1) to (4), when the liquid
crystal thickness b is made smaller so as to approach the liquid
crystal thickness a, the light transmission decreases dramatically,
and when the liquid crystal thickness b exceeds a value which is
much greater than the liquid crystal thickness a, the light
transmission also decreases dramatically. As the twist angle Tw
increases, the value which determines the upper limit of the
foregoing light transmission becomes smaller in the range from 1.0
to 5.0 .mu.m. It is believed that, since the optical rotation of
the liquid crystal layer affects the light passing through the
liquid crystal layer more dramatically as the twist angle Tw
becomes larger, the liquid crystal does not act on the light in
proportion to the thickness thereof. That is to say, it is believed
that as the twist angle Tw becomes larger, the effect of making the
liquid crystal thickness b greater than the liquid crystal
thickness a generally decreases.
[0084] FIG. 20(e) is a diagram illustrating the relationship
between the twist angle Tw at which the light transmission in the
transmissive regions takes the maximum value and the liquid crystal
thickness b. As can be seen from this diagram, the twist angle Tw
which provides the maximum light transmission in the transmissive
regions increases gradually as the liquid crystal thickness b
increases from a to about 1.8 a, and when b exceeds about 1.8 a,
the twist angle Tw which provides the maximum light transmission
dramatically decreases. In this case, the light transmission is
high when the twist angle Tw takes a value in the range of
50.ltoreq.Tw.ltoreq.70 when b lies in the range of
a<b.ltoreq.2a.
[0085] In this embodiment, although the apertures 125a are formed
so as to overlap the corresponding apertures 212a of the reflective
layer 212, as shown in FIG. 2(b), the coloring layers 214 can be
sufficiently protected by the transparent electrodes 216 since the
coloring layers 214 are fully covered by the transparent electrodes
216.
[0086] Since the thickness of the overcoat layer 215 in the liquid
crystal display panel is generally about 3 to 5 .mu.m, the overcoat
layer 215 is quite thick compared to the transparent electrodes 216
having a thickness of about 1500 to 3000 .ANG.. Accordingly, the
method of making the liquid crystal thick by providing the
protection layer with apertures or thin portions is quite
effective. Although not described in the above described
embodiment, an insulating film made from SiO.sub.2, TiO.sub.2, or
the like may be formed between the overcoat layer 215 (i.e., a
protection layer) and the transparent electrodes 216 so as to
improve the adhesiveness and the pattern features of the
transparent electrodes 216.
[0087] Referring now to FIG. 4, a second embodiment of the present
invention will be described. Since the second embodiment has the
same configuration as the first embodiment except for the structure
of the color filter substrate, which will be described later, like
parts are denoted by the same reference numerals and their
description is omitted.
[0088] As shown in FIG. 4, in this embodiment, as in the first
embodiment, a first substrate 311 has a reflective layer 312,
having reflectors 312r and apertures 312a therein, formed therein,
the reflective layer 312 has coloring layers 314 formed thereon,
and the coloring layers 314 have an overcoat layer 315 formed
thereon. Although the overcoat layer 315 is made from the same
material as the overcoat layer 215 in the first embodiment, the
overcoat layer 315 has depressions 315b formed in the regions which
overlap the corresponding apertures 312a of the reflective layer
312, and also has thin portions 315c below the depressions 315b,
thus giving rise to a difference compared to the overcoat layer of
the first embodiment, which has apertures formed in the spaces
corresponding to the thin portions 315c. The overcoat layer 315 has
transparent electrodes 316 and an alignment film 317 formed
thereon, as in the first embodiment.
[0089] In this embodiment, although the thin portions 315c lie in
the regions which overlap the corresponding apertures 312a of the
reflective layer 312, since the overcoat layer 315 is basically
transparent, the same optical effects as in the first embodiment
can be obtained. Also, in this embodiment, since the coloring
layers 314 are covered by the overcoat layer 315 even in the
regions which overlap the apertures 312a, the coloring layers 314
can be reliably protected.
[0090] Referring now to FIG. 5, a third embodiment of the present
invention will be described. Since the third embodiment has the
same configuration as the first embodiment except for the structure
of the counter substrate, like parts are denoted by the same
reference numerals and their description is omitted.
[0091] In this embodiment, the counter substrate is constructed
such that a second substrate 321 has depressions 321a formed on the
inner surface thereof (i.e., on the surface thereof facing the
first substrate 211). The depressions 321a can be easily formed by
photolithography and etching with hydrofluoric-acid-based etching
liquid. Then, the second substrate 321 has transparent electrodes
322, a hard protection film 323, and an alignment film 324
laminated on the surface thereof having the depressions 321a
thereon.
[0092] In this embodiment, not only does the color filter substrate
have the surface depressions 210a formed on the inner surface
thereof, but also the counter substrate has surface depressions
320a on the inner surface thereof which faces the corresponding
surface depressions 210a, and the liquid crystal 232 fills both the
surface depressions 210a and 320a, thereby making the liquid
crystal layer even thicker in the regions which overlap the
apertures 212a of the reflective layer 212.
[0093] Referring now to FIG. 6, a fourth embodiment of the present
invention will be described. Since the fourth embodiment has the
same configuration as the second embodiment except for the
structure of the counter substrate, like parts are denoted by the
same reference numerals and their description is omitted.
[0094] The counter substrate in this embodiment has a
light-transmitting layer 425 on a second substrate 421, and the
light-transmitting layer 425 has apertures 425a in the regions
which two-dimensionally overlap the corresponding apertures 312a of
the reflective layer 312. The light-transmitting layer 425 is
formed from, for example, an inorganic transparent layer made from
SiO.sub.2 or TiO.sub.2, or an organic resin layer made from an
acrylic resin or an epoxy resin. Preferably, the light-transmitting
layer is substantially transparent to visible light. For example,
the light-transmitting layer preferably has a light transmission of
about 70% or higher in the visible light region, and the range of
fluctuation of the light transmission over the visible light region
is preferably equal to 10% or less.
[0095] The light-transmitting layer 425 has transparent electrodes
422 and an alignment film 424 laminated thereon. The counter
substrate has surface depressions 420a, reflecting the surface
profile of the apertures 425a, formed on the inner surface thereof,
and the liquid crystal 232 fills the surface depressions 420a.
Also, in this embodiment, since the color filter substrate and the
counter substrate have the surface depressions 310a and 420a,
respectively, on the respective inner surfaces thereof, it is easy
to make the liquid crystal thickness b in the regions which
two-dimensionally overlap the apertures 312a of the reflective
layer 312 greater than the liquid crystal thickness a in the other
regions above the reflective surfaces.
[0096] Referring now to FIG. 7, a fifth embodiment of the present
invention will be described. Since the fifth embodiment has the
same configuration as the first embodiment except for the structure
of the color filter substrate, like parts are denoted by the same
reference numerals and their description is omitted.
[0097] In this embodiment, a first substrate 411 has depressions
411a and also a reflective layer 412 on the surface thereof. The
reflective layer 412 has reflectors 412r having reflective surfaces
and apertures 412a. The reflective layer 412 is configured such
that the apertures 412a lie above the corresponding depressions
411a. The reflective layer 412 has coloring layers 414 formed
thereon, and further has an overcoat layer 415 formed on the
coloring layers 414.
[0098] The coloring layers 414 in this embodiment are formed so as
to extend into the corresponding depressions 411a of the first
substrate 411 via the apertures 412a of the reflective layer 412,
and thus the coloring layers 414 have thick portions 414a formed in
the regions which overlap the corresponding apertures 412a. Also,
the thick portions 414a have depressions 414b formed on the
respective surfaces thereof so as to correspond to the respective
depressions 411a.
[0099] The overcoat layer 415 has apertures 415a, which are formed
therein as in the above described manner, transparent electrodes
416, and an alignment film 417 sequentially laminated on the
surface thereof. As a result, the depressions 414b of the coloring
layers 414 cause surface depressions 410a formed on the surface of
the color filter substrate to be deeper than the counterparts in
the first embodiment.
[0100] Since each depression 411a of the first substrate 411 allows
the corresponding coloring layer 414 to have the thick portion 414a
in the region which overlaps the corresponding aperture 412a of the
reflective layer 412, the chroma of the transmissive display can be
improved without sacrificing the brightness of the reflective
display.
[0101] Referring now to FIG. 8, a sixth embodiment of the present
invention will be described. Since the sixth embodiment has the
same configuration as the first embodiment except for the structure
of the color filter substrate, like parts are denoted by the same
reference numerals and their description is omitted.
[0102] In this embodiment, a first substrate 511 has an underlying
layer 513 formed thereon, and the underlying layer 513 has
apertures 513a therein. Although the underlying layer 513 can be
made from the same material as the light-transmitting layer of the
fourth embodiment, it may be formed from a non-light-transmitting
material. When the underlying layer 513 has a light-transmitting
property, the underlying layer 513 may have thin portions formed
therein, instead of the apertures 513a, which provide depressions
on the upper surface thereof.
[0103] The underlying layer 513 has a reflective layer 512 formed
thereon, and the reflective layer 512 has reflectors 512r having
reflective surfaces and apertures 512a lying above the apertures
513a of the underlying layer 513. Furthermore, the reflective layer
512 has coloring layers 514 formed thereon, and the coloring layers
514 have an overcoat layer 515 formed thereon. The overcoat layer
515 has apertures 515a in the regions which overlap the
corresponding apertures 512a of the reflective layer 512, and
further has transparent electrodes 516 and an alignment film 517
sequentially formed thereon.
[0104] In this embodiment, as in the above described embodiments,
while the apertures 515a of the overcoat layer 515 form surface
depressions 510a on the surface of the color filter substrate, the
apertures 513a of the underlying layer 513 form depressions 514b on
the surface of the coloring layers 514 so as to overlap the
corresponding apertures 512a of the reflective layer 512, thus
causing the surface depressions 510a to be deeper than the
counterparts in the first embodiment.
[0105] Since the apertures 513a of the underlying layer 513 allow
the coloring layers 514 to have thick portions 514a in the regions
which overlap the apertures 512a of the reflective layer 512, the
chroma of the transmissive display can be improved without
sacrificing the brightness of the reflective display.
[0106] Referring now to FIG. 9, a seventh embodiment of the present
invention will be described. Since the seventh embodiment has the
same configuration as the first embodiment except for the structure
of the color filter substrate, like parts are denoted by the same
reference numerals and their description is omitted.
[0107] In this embodiment, a first substrate 611 has a reflective
layer 612 formed thereon, the reflective layer 612 has reflectors
612r having reflective surfaces and apertures 612a formed therein.
The reflective layer 612 has a light-transmitting layer 613 formed
thereon. The light-transmitting layer 613 can be made from the same
material as the light-transmitting layer in the fourth embodiment.
The light-transmitting layer 613 has apertures 613a formed in the
regions which overlap the corresponding apertures 612a of
reflective layer 612.
[0108] The light-transmitting layer 613 has coloring layers 614
formed thereon, and the coloring layers 614 have an overcoat layer
615 formed thereon. The overcoat layer 615 has apertures 615a
formed therein, as in the above described embodiments. The
apertures 615a lie so as to two-dimensionally overlap the
corresponding apertures 612a and 613a of the reflective layer 612
and the light-transmitting layer 613, respectively. The overcoat
layer 615 has transparent electrodes 616 and an alignment film 617
sequentially laminated thereon.
[0109] With the above described structure, the color filter
substrate has surface depressions 610a formed thereon, and thus the
surface depressions 610a cause portions of the liquid crystal
facing the corresponding apertures 612a of the reflective layer 612
to be thicker than the remaining portions.
[0110] In this embodiment, as in the above described embodiments,
while the apertures 615a of the overcoat layer 615 form the
corresponding surface depressions 610a on the color filter
substrate, the apertures 613a of the light-transmitting layer 613
form depressions 614b on the surface of coloring layers 614 so as
to overlap the corresponding apertures of the reflective layer 612,
thereby causing the surface depressions 610a to be deeper than the
counterparts in the first embodiment.
[0111] Also, since the apertures 613a of the light-transmitting
layer 613 allow the coloring layers 614 to have thick portions 614a
in the regions which overlap the apertures 612a of the reflective
layer 612, the chroma of the transmissive display can be improved
without sacrificing the brightness of the reflective display.
[0112] Referring now to FIG. 10, an eighth embodiment of the
present invention will be described. In this embodiment, a first
substrate 711 has a reflective layer 712 formed thereon, and the
reflective layer 712 has reflectors 712r having reflective surfaces
and apertures 712a disposed therein. The reflective layer 712 has
an insulating film 713 made from SiO.sub.2 or TiO.sub.2 formed
thereon, and the insulating film 713 has transparent electrodes 716
formed thereon. The transparent electrodes 716 has an alignment
film 717 formed thereon. When the reflective layer 712 is
separately formed at each pixel, the transparent electrodes 716 may
be formed directly on the reflective layers 712 without having the
insulating film 713 interposed therebetween.
[0113] On the other hand, a second substrate 521 has coloring
layers 523 formed thereon, and a black matrix film 523BM is formed
in the space between adjacent pixels. The coloring layer 523 has an
overcoat layer 525 formed thereon, and the overcoat layer 525 has
apertures 525a disposed therein. The apertures 525a are arranged so
as to two-dimensionally overlap the apertures 712a of the
reflective layer 712 on the first substrate 711. The overcoat layer
525 has transparent electrodes 522 formed thereon, and further has
an alignment film 524 formed on the transparent electrodes 522.
[0114] In this embodiment, the second substrate 521, which is
opposite to the first substrate 711 having the reflective layer 712
formed thereon, has the coloring layers 523 of the color filter
formed thereon, and further has the overcoat layer 525 formed on
the coloring layers 523. The apertures 525a of the overcoat layer
525 form surface depressions 520a. Also, in this embodiment, since
the liquid crystal is thicker in the regions which overlap the
apertures 712a of the reflective layer 712 than in the remaining
regions, the same basic effects as in the above described
embodiments can be obtained.
[0115] Referring now to FIGS. 11(a) to 11(e) and FIG. 15,
fabrication methods of the liquid crystal device and the liquid
crystal device board according to fabrication method embodiments of
the present invention will be described in detail. The liquid
crystal device fabricated in this embodiment has the liquid crystal
display panel 200 according to the first embodiment shown in FIG.
1. Referring to FIG. 15, the schematic structure of the liquid
crystal display panel 200 shown in FIG. 1 will be described first.
FIG. 15 is a schematic illustration of a state in which the
semiconductor IC and the flexible wiring board of the liquid
crystal display panel 200 shown in FIG. 1 are not mounted. In the
drawing, the size of the liquid crystal display panel 200 is
adjusted for convenience of illustration as necessary, and some of
its components are omitted as necessary.
[0116] The liquid crystal display panel 200 is constructed such
that the color filter substrate 210, which has the first substrate
211 having the reflective layer 212, the coloring layers 214, and
the overcoat layer 215 laminated thereon, and which has the
transparent electrodes 216 formed on the overcoat layer 215, and
the counter substrate 220 facing the color filter substrate 210 are
bonded to each other with the sealing adhesive 230, and the liquid
crystal 232 is disposed therebetween. The transparent electrodes
216 are connected to the wiring lines 218A as described above, and
the wiring lines 218A pass between the sealing adhesive 230 and the
first substrate 211 and are lead out onto the surface of the
substrate overhang 210T. The substrate overhang 210T also has the
input terminal unit 219 formed thereon.
[0117] FIGS. 11(a) to 11(e) illustrate a fabrication process for
fabricating the color filter substrate 210 included in the liquid
crystal display panel shown in FIG. 15.
[0118] First, as shown in FIG. 11(a), the reflective layer 212, the
black matrix film 214BM, and at least one part of the coloring
layers 214 corresponding to a single color are sequentially formed
on the first substrate 211 in the region corresponding to the
liquid crystal display region A shown in FIG. 1. The reflective
layer 212 having the apertures 212a therein is formed such that a
metal material or the like is deposited on the substrate by
chemical vapor deposition or sputtering, and then the deposited
film is sputtered by lithography and etching. Also, the black
matrix film 214BM and that part of the coloring layers 214 are
formed such that a photosensitive resin made from a transparent
resin or the like containing a colorant such as a pigment or a dye
dispersed therein is coated on the reflective layer 212, and
subsequently the coated film is exposed and then developed. When
the coloring layers 214 corresponding to a plurality of colors are
to be formed in an array, the above step is repeated for each
color.
[0119] Basically, the above described laminated structure is not
formed in the regions (including a region on the substrate overhang
210T) of the liquid crystal panel 200 excluding the liquid crystal
display region A.
[0120] Then, as shown in FIG. 11(b), the first substrate 211 has a
light-transmissive protection layer 215X formed on the entire
surface thereof. The light-transmissive protection layer 215X is
made from, for example, an acrylic resin, an epoxy resin, an imide
resin, a fluorine resin, or the like. One of these fluid resins in
an uncured state is coated on the substrate and is cured by an
appropriate means including drying, photo-curing, and heat-curing.
A method such as spin coating or printing is employed as the
coating method.
[0121] Subsequently, by patterning the light-transmissive
protection layer 215X by photolithography and etching, as shown in
FIG. 11(c), the overcoat layer 215 is formed so as to be restricted
to the liquid crystal display region A. At the same time, the
apertures 215a are formed in the overcoat layer 215. In this step,
the light transmissive material which lies in the region B and does
not lie in the liquid crystal display region A is removed from the
light-transmissive protection layer 215X, wherein the region B
substantially corresponds to portions (including a portion on the
substrate overhang 210T) of the light-transmissive protection layer
215X, the portions being formed outside the sealing adhesive 230 as
shown in FIG. 15.
[0122] Although the present invention is characterized in that the
apertures 215a, the depressions 315b, or the thin portions 315c are
formed in the overcoat layer 215 (refer to the second embodiment),
as described above, the apertures, the depressions, or the thin
portions can be formed at the same time as when the overcoat layer
215 is patterned, and thus the color filter substrate 210 can be
fabricated only by changing the patterning pattern without
increasing the number of man-hours or putting additional effort
into the conventional fabrication process.
[0123] Subsequently, as shown in FIG. 11(d), a transparent
conductive layer 216X formed of a transparent conductor made from
ITO (indium tin oxide) or the like is formed on the entire surface
of the substrate. The transparent conductive layer 216X is
deposited by sputtering. Then, by patterning the transparent
conductive layer 216X by photolithography and etching, the
transparent electrodes 216, the wiring lines 218A, and the input
terminal unit 219 are formed all at the same time, as shown in FIG.
11(e). Although not shown in these drawings, the wiring lines 218B
shown in FIG. 1 are formed at the same time in the above described
step.
[0124] A fabrication method of the foregoing liquid crystal device
board includes a step for forming a reflective layer having
apertures on the substrate, a step for forming coloring layers on
the reflective layer, and a step for forming a substantially
light-transmissive protection layer having apertures or thin
portions in the regions which overlap the apertures of the
reflective layer above the coloring layers. In the step for forming
the protection layer, the apertures or the thin portions of the
protection layer form depressions on the surface of the protection
layer. With this arrangement, when the transflective liquid crystal
device is constructed with this substrate, by disposing the
apertures or the thin portions in the protection layer so as to
form the depressions on the surface thereof, the liquid crystal
layer in the regions where the apertures of the reflective layer
are disposed can be made thicker than in the other regions. More
particularly, since the protection layer formed on the coloring
layers is generally thicker than the other layered components
(e.g., the reflective layer and the transparent electrodes) forming
the layer structure, the depressions for making portions of the
liquid crystal layer thicker can be easily formed.
[0125] It is preferable that the step for forming the protection
layer include a processing phase for removing at least a part of
the material forming the protection layer from portions of the
protection layer, the portions overlapping the regions where the
coloring layers are not formed and where the apertures of the
reflective layer are formed, and the apertures or the thin portions
of the protection layer are formed in this processing phase. When
the step for forming the protection layer includes a processing
phase (i.e., the patterning processing phase) for removing at least
a part of the transmissive material in the regions where the
coloring layers on the substrate are not formed, the apertures or
the thin portions are formed at the same time in this processing
phase, whereby the conventional fabrication method can be applied
simply by changing the patterning pattern without increasing the
number of man-hours into the fabrication process.
[0126] A fabrication method of the liquid crystal device includes a
step for forming a reflective layer having apertures on the
substrate, a step for forming coloring layers on the reflective
layer, a step for forming a substantially light-transmissive
protection layer having apertures or thin portions in the regions
which overlap the apertures of the reflective layer above the
coloring layers, and a step for disposing liquid crystal on the
protection layer. In the step for disposing the liquid crystal, the
liquid crystal is infused into depressions formed by the apertures
or thin portions of the protection layer. With this arrangement,
the depressions are formed by the apertures or the thin portions of
the protection layer and the depressions are filled with the liquid
crystal, whereby the liquid crystal layer can be made thicker in
the regions where the apertures of the reflective layer are
disposed. In particular, since an additional layer is not needed
and, furthermore, since the protection layer has a sufficient
thickness, the thickness of the liquid crystal layer can be easily
changed so as to improve the utilization efficiency of light
necessary to achieve the transmissive display.
[0127] Also, another fabrication method of the liquid crystal
device according to the present invention includes a step for
forming a reflective layer having apertures on one of a pair of
substrates, a step for forming coloring layers on the reflective
layer, a step for forming a substantially light-transmissive
protection layer having apertures or thin portions in the regions
which overlap the apertures of the reflective layer above the
coloring layers, and a step for disposing liquid crystal between
the pair of substrates. In the step for disposing the liquid
crystal, the liquid crystal is infused into depressions formed by
the apertures or thin portions of the protection layer.
[0128] Furthermore, another fabrication method of the liquid
crystal device according to the present invention includes a step
for forming a reflective layer having apertures on one of a pair of
substrates, a step for forming coloring layers on the other one of
the pair of substrates, a step for forming a substantially
light-transmissive protection layer having apertures or thin
portions in the regions which overlap the apertures of the
reflective layer above the coloring layers, and a step for
disposing liquid crystal between the pair of substrates. In the
step for disposing the liquid crystal, the liquid crystal is
infused into depressions formed by the apertures or thin portions
of the protection layer.
[0129] In any of the above described fabrication methods, it is
preferable that the step for forming the protection layer include a
processing phase for removing at least a part of the material
forming the protection layer from portions of the protection layer,
the portions overlapping the regions where the coloring layers are
not formed and where the apertures of the reflective layer are
formed, and the apertures or the thin portions of the protection
layer are formed in this processing phase.
[0130] Referring now to FIG. 17, a further detailed example
applicable to the above described embodiments will be described.
FIG. 17 includes an enlarged partial sectional view schematically
illustrating a part of the sectional structure of the color filter
substrate and a schematic plan view of a part of the color filter
lying in the region corresponding to the color filter substrate,
wherein the enlarged partial sectional view is taken along the line
P-Q indicated in the schematic plan view.
[0131] In this example, a substrate 1401 has a light-transmitting
layer 1414 formed thereon. The light-transmitting layer 1414 is
made from a light-transmissive material such as a transparent
material, and, in particular, is preferably formed from an
organic-insulative material. The light-transmitting layer 1414 has
an indented pattern, that is, a regularly or irregularly repeated
pattern of peaks and troughs, formed on a surface 1414a. The
indented pattern is formed by selectively removing the transparent
material by etching or the like so as to form an indented shape,
and, in some cases, by additionally imparting fluidity to the
transparent material having the foregoing indented shape with heat
or the like so as to smooth the indented shape. The
light-transmitting layer 1414 is about 2 .mu.m thick, for example.
Instead of forming the light-transmitting layer 1414, the substrate
1401 may have an indented pattern formed on the surface thereof by
etching or the like. Also, instead of disposing such a
light-transmitting layer 1414, or forming an indented pattern on
the surface of the substrate 1401, a diffusing layer, a scattering
layer, or the like may be disposed closer to the observation side
than to a reflective layer, which will be described later.
[0132] The light-transmitting layer 1414 has a reflective layer
1411 formed thereon made from Al, an Al alloy, silver, an APC
alloy, or the like. The reflective layer 1411 is formed by
sputtering, chemical vapor deposition, or the like. The reflective
layer 1411 has an indented reflective surface since it is formed on
the surface of the light-transmitting layer 1414. The reflective
layer 1411 is about 0.2 .mu.m thick, for example, and has one
aperture 1411a at each pixel.
[0133] The light-transmitting layer 1414 and the reflective layer
1411 have a color filter 1412, made from a known photosensitive
resin or the like, formed thereon. The color filter 1412 includes
coloring layers having hyperchromic portions 1412rc (red
hyperchromic portions), 1412gc (green hyperchromic portions), and
1412bc (blue hyperchromic portions) formed on the apertures 1411a,
and hypochromic portions 1412r (red hypochromic portions), 1412g
(green hypochromic portions), and 1412b (blue hypochromic portions)
formed on a reflective layer 1411.
[0134] Also, the hypochromic portions 1412r, 1412g, and 1412b have
one stacked black matrix film 1412BM, which comprises the
hyperchromic portions 1412rc, 1412gc, and 1412bc laminated therein,
formed in each space between two adjacent pixels. The stacked black
matrix film 1412BM is constructed such that, for example, the
hypochromic portion 1412b, the hypochromic portion 1412g, and the
hypochromic portion 1412r are laminated sequentially from the
bottom so as to be about 1.0 .mu.m thick, about 0.5 .mu.m thick,
and about 0.5 .mu.m thick, respectively.
[0135] The coloring layers formed as described above have
protection layers 1412p formed thereon, wherein the protection
layers 1212p are formed of a light transmissive material made from
an acrylic resin or the like. The protection layers 1412p are
formed on the hypochromic portions 1412r, 1412g, and 1412b, but are
not formed on the hyperchromic portions 1412rc, 1412gc, and 1412bc.
The protection layers 1412p are formed such that, for example, an
inorganic layer or an organic layer is formed on the entire surface
of the color filter 1412, and then portions of the layer lying
directly above the apertures 1411a are selectively removed by
photolithography or the like. The protection layers 1412p are made
from a transparent organic resin such as an acrylic resin or an
epoxy resin, or from a transparent inorganic material such as
SiO.sub.2 or TiO.sub.2. The protection layers 1412p are about 2.2
.mu.m thick, for example.
[0136] The protection layers 1412p have transparent electrodes
1413, formed of a transparent conductor, formed thereon. Since the
transparent electrodes 1413 are formed on the protection layers
1412p, the transparent electrodes 1413 have a sectional profile
directly affected by the presence of the protection layers 1412p,
leading to a typical height difference .DELTA.h between the
portions where the protection layers 1412p exist and the other
portions where the protection layers 1412p do not exist. The height
difference .DELTA.h is about 2.0 .mu.m, for example. The spaces
between the adjacent transparent electrodes 1413 lie above the
corresponding stacked black matrix films 1412BM. Each space between
the adjacent transparent electrodes 1413 shown in the drawings is
about 8 to 10 .mu.m.
[0137] In this example, since the stacked black matrix films 1412BM
are formed by laminating the hyperchromic portions 1412rc, 1412gc,
and 1412bc, the light transmission of this laminated structure can
be reduced compared to the structure in which the hypochromic
portions are laminated, and accordingly light-shielding in the
regions between the adjacent pixels can be achieved more
effectively. In addition, since each of the stacked black matrix
films 1412BM is stacked directly on any one of the hypochromic
portions 1412r, 1412g, and 1412b formed in the pixel regions, the
light transmission in the regions where the stacked black matrix
films 1412BM are disposed can be further reduced and also the
height difference .DELTA.h can be easily achieved. Although each
stacked black matrix film 1412BM has a three-layered structure on
the hypochromic portion, the stacked black matrix film 1412BM may
have a two-layered structure or a single-layered structure.
[0138] In this example, when the color filter substrate is
configured by using the example dimensions shown above, the overall
thickness of the color filter substrate is 5.2 to 5.3 .mu.m.
Accordingly, a TN liquid crystal display panel or an STN liquid
crystal display panel can be configured by providing the liquid
crystal layer in the reflective regions with thickness of 3.25
.mu.m. With this arrangement, the thickness of the liquid crystal
layer in the transmissive regions is 5.25 .mu.m. The liquid crystal
layer is formed of a nematic liquid crystal, has a twist angle Tw
of about 60 degrees, and satisfies the foregoing condition (2).
Since the liquid crystal layer is about 60% thicker in the
transmissive regions than in the reflective regions, the light
transmission for both reflective display and transmissive display
can be improved by optimizing the retardation of the liquid crystal
layer, and, as a result, bright display can be achieved.
[0139] Referring now to FIGS. 18 and 19, a structural example of
the color filter 1412 according to the foregoing example of the
present invention will be described. This structural example is
applicable not only to the color filter in the foregoing example
but also to those in the foregoing embodiments. FIGS. 18(a), 18(b),
and 18(c) are diagrams of spectral transmittances, xy chromaticity
in the CIE colorimetric system (1931), and a*b* chromaticity in the
CIE colorimetric system (1976), respectively, of light passing
through the hyperchromic portions of the above-described color
filter. FIGS. 19(a), 19(b), and 19(c) are diagrams of spectral
transmittances, xy chromaticity in the CIE colorimetric system
(1931), and a*b* chromaticity in the CIE colorimetric system
(1976), respectively, of light passing through the hypochromic
portions of the above-described color filter. These diagrams
illustrate the results in which light from the same C light source
is transmitted once through each hyperchromic portion or each
hypochromic portion and the spectral transmittance and the
chromaticity coordinates of the transmitted light after one pass
are analyzed.
[0140] As shown in FIG. 18, the major transmissive wavelength range
of the light passing through the red hyperchromic portion (R) lies
from 600 to 700 nm, the mean light transmission in this range is
about 90%, and, in particular, the maximum light transmission
(about 95%) is in the range of 640 to 700 nm. The major
transmissive wavelength range of the light passing through the
green hyperchromic portion (G) lies from 495 to 570 nm, the mean
light transmission in this range is about 85%, and, in particular,
the maximum light transmission (about 90%) is in the range of 510
to 550 nm. The major transmissive wavelength range of the light
passing through the blue hyperchromic portion (B) lies from 435 to
500 nm, the mean light transmission in this range is about 85%,
and, in particular, the maximum light transmission (about 88%) is
in the range of 445 to 480 nm.
[0141] Also, Y values in the CIE colorimetric system (1931) of the
light passing through the red hyperchromic portion (R), the green
hyperchromic portion (G), and the blue hyperchromic portion (B) are
about 24 to 26, 70 to 72, and 29 to 31, respectively. L* values in
the CIE colorimetric system (1976) of the light passing through the
red hyperchromic portion (R), the green hyperchromic portion (G),
and the blue hyperchromic portion (B) are about 56 to 58, 86 to 88,
and 60 to 62, respectively.
[0142] In addition, the areas of two triangles formed by two groups
of three apexes in the two chromaticity diagrams corresponding to
the chromaticity values of the light passing through the red
hyperchromic portion (R), the green hyperchromic portion (G), and
the blue hyperchromic portion (B) are about 0.05 (in the xy
chromaticity diagram) and about 7000 (in the a*b* chromaticity
diagram).
[0143] On the other hand, as shown in FIG. 19, the major
transmissive wavelength range of the light passing through the red
hypochromic portion (R) lies from 585 to 700 nm, the mean light
transmission in this range is about 93%, and, in particular, the
maximum light transmission (about 96%) is in the range of 590 to
700 nm. The major transmissive wavelength range of the light
passing through the green hypochromic portion (G) lies from 480 to
600 nm, the mean light transmission in this range is about 92%,
and, in particular, the maximum light transmission (about 94%) is
in the range of 500 to 580 nm. The major transmissive wavelength
range of the light passing through the blue hypochromic portion (B)
lies from 430 to 510 nm, the mean light transmission in this range
is about 89%, and, in particular, the maximum light transmission
(about 92%) is in the range of 440 to 500 nm.
[0144] Also, Y values in the CIE colorimetric system (1931) of the
light passing through the red hypochromic portion (R), the green
hypochromic portion (G), and the blue hypochromic portion (b) are
about 46 to 48, 89 to 91, and 44 to 46, respectively. L* values in
the CIE colorimetric system (1976) of the light passing through the
red hypochromic portion (R), the green hypochromic portion (G), and
the blue hypochromic portion (B) are about 73 to 75, 95 to 97, and
72 to 74, respectively.
[0145] In addition, the areas of two triangles formed by two groups
of three apexes in the two chromaticity diagrams corresponding to
the chromaticity values of the light passing through the red
hypochromic portion (R), the green hypochromic portion (G), and the
blue hypochromic portion (B) are about 0.01 (in the xy chromaticity
diagram) and about 1700 (in the a*b* chromaticity diagram).
[0146] As described above, when the optical density features of the
hyperchromic portions and the hypochromic portions are compared to
each other, the Y values corresponding to luminous transmission, or
the L* values corresponding to brightness, of the hypochromic
portions are greater than those of the hyperchromic portions. These
values of the hypochromic portions are preferably about 1.2 to 2.5
times as large as those of the hyperchromic portions. Also,
regarding the triangular areas in the chromaticity diagrams
corresponding to chroma, the triangular area in the chromaticity
diagram of the hyperchromic portions is greater than that of the
hypochromic portions, and is preferably about 3 to 8 times as large
as that of the hypochromic portions.
[0147] The optical density can be defined not only by the optical
characteristics described above but also by the fabrication
conditions or the structure of the color filter. For example, the
magnitude relation of the amount of a colorant such as a pigment or
a dye, which is mixed in the coloring layers in a dispersed state
when the coloring layers of the color filter are formed, can be
used as a definition factor. That is, the amount (weight or volume)
of the colorant per unit volume of the hyperchromic portions is
designed to be greater than that of the hypochromic portions.
[0148] As described above, since suitable color display in the
transmissive display and the reflective display can be achieved by
providing the coloring layers of the color filter with the
hyperchromic portions in the transmissive regions and the
hypochromic portions in the reflective regions, respectively, in
the above described example, the improvement in the light
transmission obtained by setting the liquid crystal thickness a of
the reflective regions and the liquid crystal thickness b of the
transmissive regions in the foregoing ranges can be utilized more
effectively, and thus high-definition color display can be
achieved.
[0149] Lastly, an electronic apparatus according to an electronic
apparatus embodiment will be described wherein the electronic
apparatus uses a liquid crystal device, including the foregoing
liquid crystal display panel, as a display device. FIG. 13 is a
schematic block diagram illustrating the overall configuration of
this embodiment. An electronic apparatus shown in this drawing has
the liquid crystal display panel 200, the same as described above,
and control means 1200 for controlling it. In the drawing, the
liquid crystal display panel 200 is conceptually illustrated so as
to have a panel structure 200A and a drive circuit 200B including a
semiconductor IC and so forth. The control means 1200 includes a
display-information output source 1210, a display-information
process circuit 1220, a power circuit 1230, and a timing generator
1240.
[0150] The display-information output source 1210 has a memory such
as a ROM (read only memory) and a RAM (random access memory), a
storage unit including a magnetic storage disk, an optical storage
disk, and so forth, and a tuning circuit for outputting a tuned
digital image signal, and sends display information in the form of
an image signal and the like with a predetermined format to the
display-information process circuit 1220 in response to a variety
of clock signals generated by the timing generator 1240.
[0151] The display-information process circuit 1220 has a variety
of known circuits such as a serial-parallel conversion circuit, an
amplification and reversion circuit, a rotation circuit, a gamma
correction circuit, and a clamp circuit, processes the input
display information, and sends the processed image information
together with a clock signal CLK to the drive circuit 200B. The
drive circuit 200B includes a scan line drive circuit, a data line
drive circuit, and a testing circuit. The power circuit 1230 feeds
a predetermined voltage to each of the above described
components.
[0152] FIG. 14 illustrates a portable phone as an example of the
electronic apparatus according to this embodiment of the present
invention. A portable phone 2000 is constructed such that a casing
2010 has a circuit board 2001 disposed therein and the circuit
board 2001 has the foregoing liquid crystal display panel 200
mounted thereon. The casing 2010 has an array of operation buttons
2020 on the front surface thereof and an antenna 2030 retractably
attached at one end thereof. A receiver 2040 has a speaker disposed
therein and a transmitter 2050 has a built-in microphone
therein.
[0153] The display surface (the foregoing liquid crystal display
region A) of the liquid crystal display panel 200 installed in the
casing 2010 is visible through a display window 2060.
[0154] The liquid crystal device and the electronic apparatus
according to the present invention are not limited to the foregoing
examples illustrated in the drawings, but those skilled in the art
will appreciate that various modifications can be made without
departing from the spirit of the present invention. For example,
although the liquid crystal display panel described in the
foregoing embodiments has a passive matrix structure, the present
invention is applicable to a liquid crystal device of an active
matrix type using an active element such as a TFT (thin film
transistor) or a TFD (thin film diode). Furthermore, although the
liquid crystal display panel according to the foregoing embodiments
has a so-called COG type structure, the present invention is
applicable to a liquid crystal display panel on which an IC chip is
not directly mounted, for example to a liquid crystal display panel
to which a flexible wiring board or a TAB board is connected.
[0155] As described above, according to the present invention,
since the utilization efficiency of transmitted light necessary to
achieve the transmissive display is improved, the amount of
illuminating light necessary to achieve the transmissive display
can be reduced, and also the reflective display can be made
brighter by reducing the areas of the apertures in the reflective
layer. In addition, since these are achieved simply by providing
apertures or thin portions in the protection layer on the coloring
layers, the liquid crystal device according to the present
invention can be fabricated without complicating its fabrication
process.
[0156] The entire disclosures of Japanese Patent Application Serial
Nos. 2001-226769 filed Jul. 26, 2001 and 2002-188598 filed Jun. 27,
2002 are expressly incorporated by reference herein.
* * * * *