U.S. patent application number 16/855265 was filed with the patent office on 2020-08-06 for method of manufacturing optical film.
The applicant listed for this patent is Semiconductor Energy Laboratory Co., Ltd.. Invention is credited to Yuugo GOTO, Yumiko OHNO, Akio YAMASHITA.
Application Number | 20200249524 16/855265 |
Document ID | / |
Family ID | 1000004777904 |
Filed Date | 2020-08-06 |
United States Patent
Application |
20200249524 |
Kind Code |
A1 |
YAMASHITA; Akio ; et
al. |
August 6, 2020 |
METHOD OF MANUFACTURING OPTICAL FILM
Abstract
To provide a method of manufacturing an optical film formed on a
plastic substrate. There is provided a method of manufacturing an
optical film including the steps of laminating a separation layer
and an optical filter on a first substrate, separating the optical
filter from the first substrate, attaching the optical filter to a
second substrate. Since the optical film manufactured according to
the invention has flexibility, it can be provided on a portion or a
display device having a curved surface. Further, the optical film
is not processed at high temperatures, and hence, an optical film
having high yield with high reliability can be formed. Furthermore,
an optical film having an excellent impact resistance property can
be formed.
Inventors: |
YAMASHITA; Akio; (Atsugi,
JP) ; OHNO; Yumiko; (Atsugi, JP) ; GOTO;
Yuugo; (Isehara, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Semiconductor Energy Laboratory Co., Ltd. |
Atsugi-shi |
|
JP |
|
|
Family ID: |
1000004777904 |
Appl. No.: |
16/855265 |
Filed: |
April 22, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15933428 |
Mar 23, 2018 |
10634944 |
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16855265 |
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14645469 |
Mar 12, 2015 |
9927653 |
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15933428 |
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13281551 |
Oct 26, 2011 |
8981641 |
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14645469 |
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10595310 |
Apr 6, 2006 |
8048251 |
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PCT/JP2004/016180 |
Oct 25, 2004 |
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13281551 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02B 5/223 20130101;
G02F 1/133516 20130101; B32B 2551/00 20130101; G02B 5/201 20130101;
B32B 2457/202 20130101 |
International
Class: |
G02F 1/1335 20060101
G02F001/1335; G02B 5/22 20060101 G02B005/22; G02B 5/20 20060101
G02B005/20 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 28, 2003 |
JP |
2003-367326 |
Claims
1. (canceled)
2. A method of manufacturing a display device, comprising the steps
of: preparing a lamination layer that comprises a substrate, a
separation layer over the substrate, an organic resin layer over
the separation layer; and irradiating the lamination layer with a
linear laser beam from the substrate side and separating the
substrate from the lamination layer.
3. The method according to claim 2, wherein the separation layer
comprises metal oxide.
4. A method of manufacturing a display device, comprising the steps
of: preparing a lamination layer that comprises a substrate, a
separation layer over the substrate, an organic resin layer over
the separation layer; and irradiating the lamination layer with a
linear laser beam from the substrate side and separating the
substrate from the lamination layer, wherein the display device
comprises a light emitting element that overlaps with one of a red
colored layer, a green colored layer, and a blue colored layer.
5. The method according to claim 4, wherein the separation layer
comprises metal oxide.
6. A method of manufacturing a display device, comprising the steps
of: preparing a lamination layer that comprises a substrate, a
separation layer over the substrate, an organic resin layer over
the separation layer; and irradiating the lamination layer with a
linear laser beam from the substrate side and separating the
substrate from the lamination layer, wherein the display device
comprises a plastic substrate and a light emitting element that
overlaps with one of a red colored layer, a green colored layer,
and a blue colored layer.
7. The method according to claim 6, wherein the separation layer
comprises metal oxide.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 15/933,428, filed Mar. 23, 2018, now allowed, which is a
continuation of U.S. application Ser. No. 14/645,469, filed Mar.
12, 2015, now U.S. Pat. No. 9,927,653, which is a continuation of
U.S. application Ser. No. 13/281,551, filed Oct. 26, 2011, now U.S.
Pat. No. 8,981,641, which is a continuation of U.S. application
Ser. No. 10/595,310, filed Apr. 6, 2006, now U.S. Pat. No.
8,048,251, which is a U.S. National Phase of International Patent
Application No. PCT/JP2004/016180, filed Oct. 25, 2004, which
claims the benefit of a foreign priority application filed in Japan
as Serial No. 2003-367326 on Oct. 28, 2003, all of which are
incorporated by reference.
TECHNICAL FIELD
[0002] The present invention relates to a method of manufacturing
an optical film formed over a plastic substrate.
BACKGROUND ART
[0003] In recent years, a technique of forming a thin film
transistor (TFT) using a semiconductor thin film (with a thickness
of approximately from several nm to several hundreds nm), which is
formed over a substrate with an insulated surface, has been
attracting attention. The thin film transistor has been widely
applied in various electronic devices such as an IC and an
electronic apparatus. In particular, development related to the
thin film transistor as a switching element for a liquid crystal
panel and a light emitting display panel has been hurried.
[0004] With respect to a liquid crystal display panel, a liquid
crystal material is sandwiched between an element substrate and an
opposing substrate. Here, TFTs using amorphous silicon or
polysilicon as semiconductors are arranged in matrix, and pixel
electrodes, source wirings and gate wirings connecting to each TFT
are formed over the element substrate respectively. The opposing
substrate having an opposing electrode is placed opposite to the
element substrate. Further, a color filter for color display is
formed over the element substrate or the opposing substrate.
Polarizing plates are then arranged over the element substrate and
the opposing substrate as optical shutters, respectively, to
display color images.
[0005] The color filter of the liquid crystal display device has
colored layers consisting of R (red), G (green), B (blue), and a
light shielding mask (black matrix) covering gaps between pixels,
and extracts red light, green light, and blue light by transmitting
light therethrough. A light shielding mask for the color filter is
generally made from a metal film or an organic film containing a
black pigment. The color filter is arranged at a position
corresponding to the pixels, thereby being capable of changing the
colors of light to be extracted for each pixel. Note that, the
position corresponding to the pixels indicates a position that
accords with a pixel electrode.
[0006] With respect to a light emitting display device, there are a
colorizing method by arranging light emitting elements that emit
red light, green light, or blue light in matrix;
[0007] a colorizing method by utilizing a color filter with use of
a light emitting element that emits white light; and the like. The
colorizing method by utilizing the color filter with use of the
light emitting element that emits white color is similar to a
colorizing method for a liquid crystal display device using a color
filter in principle (see patent document 1).
[0008] [Patent document 1]: Japanese Patent Application Laid-Open
No. 2001-217072
DISCLOSURE OF INVENTION
[0009] Conventionally, a color filter used for a liquid crystal
display device has been formed over a glass substrate. Therefore,
there has been a problem in which the color filter formed over the
glass substrate and the liquid crystal display device using the
color filter have poor impact resistance properties and tend to be
cracked easily as the thickness of the glass substrate is reduced.
Consequently, it has been difficult to fabricate a thin liquid
crystal display device.
[0010] Further, since the glass substrate does not have
flexibility, it has been difficult to form a color film on a
portion or a display device that has a curved surface.
[0011] Furthermore, a colored resin and a pigment dispersing resin
have been generally used as a raw material for the color filter. In
order to cure these resins, however, it is necessary to carry out a
step of heating at constant temperatures. Therefore, it has been
difficult to form the color filter over a thermoplastic
substrate.
[0012] According to the above-mentioned problems, the present
invention provides a method of manufacturing an optical film formed
over a plastic substrate.
[0013] According to one aspect of the invention, there is provided
a method of manufacturing an optical film, wherein after forming a
separation layer and a subject body having an optical filter over a
first substrate, a second substrate is attached to the subject body
by using a first adhesive material so that the second substrate
faces the first substrate, and the separation is caused between the
separation layer and the subject body.
[0014] According to another aspect of the invention, there is
provided a method of manufacturing an optical film, wherein after
forming a separation layer and a subject body having an optical
filter over a first substrate, a support medium is attached to the
subject body by using a peelable adhesive agent so that the support
medium faces the subject body, and the separation is caused between
the separation layer and the subject body, and after forming a
second substrate on the subject body by using a adhesive material,
the support medium and the peelable adhesive agent is separated
from the optical filter.
[0015] Note, the separation layer is formed of an element selected
from titanium (Ti), aluminum (Al), tantalum (Ta), tungsten (W),
molybdenum (Mo), copper (Cu), chromium (Cr), neodymium (Nd), iron
(Fe), nickel (Ni), cobalt (Co), ruthenium (Ru), rhodium (Rh),
palladium (Pd), osmium (Os), iridium (Ir); a single layer composed
of an alloy material or a compound material containing the
above-mentioned elements as its main constituent; a lamination
layer of the single layers. Further, the subject body comprises
silicon oxide, silicon oxynitride, or metal oxide.
[0016] According to another aspect of the invention, there is
provided a method of manufacturing an optical film, wherein after
forming a metal layer, an insulating layer, and an optical filter
over a first substrate, a second substrate is attached to the
optical filter, and the first substrate is separated from the
optical filter.
[0017] According to another aspect of the invention, there is
provided a method of manufacturing an optical film, wherein after
forming a metal layer, an insulating layer, and an optical filter
over a first substrate, the optical filter is separated from the
first substrate, and a second substrate is attached to the optical
filter.
[0018] In the present invention, a metal oxide layer may be formed
between the metal layer and the insulating layer simultaneously
with forming the metal layer and the insulating layer.
[0019] Further, the optical filter may be formed after heating the
insulating layer to form a metal oxide layer between the metal
layer and the insulating layer.
[0020] After forming the optical filter, a metal oxide layer may be
formed between a separation layer and the insulating layer by
heating.
[0021] The insulating layer may be formed after oxidizing a surface
of the metal layer to form a metal oxide film.
[0022] In a step of separating, the optical filter from the first
substrate, separation is caused between the metal layer and the
insulating layer, typically, between the metal layer and the metal
oxide layer, or between the metal oxide layer and the insulating
layer, or in the metal oxide layer by using a physical means.
[0023] The optical filter is a color filter, a color conversion
filter, or a hologram color filter.
[0024] The second substrate is made from a plastic substrate. At
this moment, the optical film is a film including a color filter, a
color conversion filter, or a hologram color filter.
[0025] As the second substrate, an optical film can be used. A
color film, a polarizing plate, an elliptical polarizing plate
composed of a retardation plate and a polarizing plate, and a light
reflection film can be used as the optical film. At this time, the
optical film having the optical filter exhibits plural optical
functions.
[0026] It is preferable that the first substrate be a
heat-resistant substrate. Typically, a glass substrate, a quartz
substrate, a ceramic substrate, a silicon substrate, a metal
substrate, and a stainless substrate can be cited as representative
examples of the substrate.
[0027] As representative examples of the metal layer, an element
selected from titanium (Ti), aluminum (Al), tantalum (Ta), tungsten
(W), molybdenum (Mo), copper (Cu), chromium (Cr), neodymium (Nd),
iron (Fe), nickel (Ni), cobalt (Co), ruthenium (Ru), rhodium (Rh),
palladium (Pd), osmium (Os), iridium (Ir); a single layer composed
of an alloy material or a compound material containing the
above-mentioned elements as its main constituent; a lamination
layer of the single layers; and nitrides of these materials can be
cited.
[0028] The insulating layer is preferably formed of oxides, for
example, a single layer of silicon oxide, silicon oxynitride, or
metal oxide, or a lamination layer thereof.
[0029] The metal oxide layer is a layer that is formed by oxidizing
a part of the metal layer by a heat treatment performed at a time
of forming the insulating layer or after forming the insulating
layer. Typically, the metal oxide layer is an oxide of an element
selected from titanium (Ti), aluminum (Al), tantalum (Ta), tungsten
(W), molybdenum (Mo), copper (Cu), chromium (Cr), neodymium (Nd),
iron (Fe), nickel (Ni), cobalt (Co), ruthenium (Ru), rhodium (Rh),
palladium (Pd), osmium (Os), and iridium (Ir).
[0030] In the invention, a display device indicates a device using
a display element, that is, an image display device. Further, the
display device includes all of a module in which a light emitting
element is attached with a connector, e.g., a FPC (flexible printed
circuit), a TAB (tape automated bonding) tape, or a TCP (tape
carrier package); a module having a printed wiring board provided
on an end of a TAB tape or a TCP; and a module in that a display
element is directly mounted with an IC (integrated circuit) or a
CPU by the COG (chip on glass) technique.
[0031] According the following embodiments, an optical filter can
be formed over a plastic substrate. That is, an optical film in
which an optical filter is formed over a plastic substrate can be
manufactured. Since the optical film manufactured according to the
invention has flexibility, the optical film can be provided on a
portion or a display device having a curved surface. Further, the
optical film is not subjected to a treatment at high temperatures,
and hence, the optical film can be formed to have high reliability
with high yield. In addition, an optical film having an excellent
impact resistance property can be formed.
[0032] A display device using the optical film manufactured
according to the invention has a structure in which a layer with
elements formed therein and the optical film are separately formed
through different steps, and subsequently the layer and the optical
film are attached to each other. By utilizing the structure, yield
of the layer with elements formed therein, i.e., a TFT and a
display element, and yield of the optical film can be controlled
individually, thereby suppressing the decrease of the yield for the
display device totally.
[0033] Further, steps for manufacturing an active matrix substrate
and steps for manufacturing an optical film can be simultaneously
run, reducing the manufacturing lead time for a display device.
[0034] Furthermore, since a plastic substrate is used, a display
device having an improved impact resistance property with reduced
weight can be manufactured.
BRIEF DESCRIPTION OF DRAWINGS
[0035] FIGS. 1A to 1E are cross sectional views explaining steps of
manufacturing an optical film according to the present
invention;
[0036] FIGS. 2A to 2E are cross sectional views explaining steps of
manufacturing an optical film according to the invention;
[0037] FIGS. 3A to 3E are cross sectional views explaining steps of
manufacturing a substrate having a color filter according to the
invention;
[0038] FIGS. 4A to 4D are cross sectional views explaining steps of
manufacturing a substrate having a color filter according to the
invention;
[0039] FIGS. 5A and 5B are cross sectional views explaining a light
emitting display device having a color filter according to the
invention;
[0040] FIGS. 6A and 6B are cross sectional views explaining a
liquid crystal display device having a color filter according to
the invention;
[0041] FIGS. 7A and 7B are top view and cross sectional view
explaining a light emitting display device panel having a color
filter according to the invention;
[0042] FIGS. 8A and 8B are top view and cross sectional view
explaining a liquid crystal display device having a color filter
according to the invention;
[0043] FIGS. 9A and 9B are diagrams explaining a substrate having a
color filter that is manufactured according to the invention;
and
[0044] FIGS. 10A to 10C are diagrams explaining examples of
electronic appliances.
BEST MODE FOR CARRYING OUT THE INVENTION
[0045] The best modes of the present invention will hereinafter be
described with reference to the accompanying drawings. As will be
easily understood by the person skilled in the art, the present
invention can be embodied in several forms, and the embodiment
modes and its details can be changed and modified without departing
from the purpose and scope of the present invention. Accordingly,
interpretation of the present invention should not be limited to
descriptions mentioned in embodiment modes. Note that, portions
identical to each other are denoted by same reference numerals in
the accompanying drawings, and will not be further explained.
[Embodiment Mode 1]
[0046] A method of manufacturing an optical film over a plastic
substrate will be described with reference to FIGS. 1A to 1E.
[0047] Firstly, a metal layer 102 is formed on a first substrate
101 as shown in FIG. 1A. As the first substrate, a heat-resistant
material, that is, a material that can withstand a heat treatment
in a step of manufacturing the optical film and a step of
separating is used. Typically, a glass substrate, a quartz
substrate, a ceramic substrate, a silicon substrate, a metal
substrate, or a stainless substrate can be used.
[0048] The metal layer 102 may be formed of an element selected
from titanium (Ti), aluminum (Al), tantalum (Ta), tungsten (W),
molybdenum (Mo), copper (Cu), chromium (Cr), neodymium (Nd), iron
(Fe), nickel (Ni), cobalt (Co), ruthenium (Ru), rhodium (Rh),
palladium (Pd), osmium (Os), iridium (Ir); a single layer composed
of an alloy material or a compound material containing the
above-mentioned elements as its main constituent; or a lamination
layer of the single layers; or nitrides of these, typically a
single layer composed of molybdenum or an alloy containing
molybdenum or a lamination layer thereof. Note that, conditions of
the subsequent separating step are changed by adjusting the
composition ratio of metal for alloy in the metal layer, or the
composition ratio of oxygen or nitrogen contained in the metal
layer, properly. Therefore, the separating step can be adapted to
various kinds of processing. The film thickness of the metal layer
102 is set to 10 to 200 nm, preferably, 50 to 75 nm.
[0049] Next, an oxide layer 103 is formed on the metal layer or the
nitride layer 102. At this moment, a metal oxide layer is formed
between the metal layer 102 and the oxide layer 103. When
separating is caused in the subsequent step, separation will be
caused inside the metal oxide layer, in an interface between the
metal oxide layer and the oxide layer, or in an interface between
the metal oxide layer and the metal layer. As for the oxide layer
103, a layer composed of silicon oxide, silicon oxynitride, or
metal oxide may be formed by sputtering or plasma CVD. It is
desirable that the film thickness of the oxide layer 103 be
approximately 1 to 3 times, preferably, at least 1.5 to 2 times as
large as that of the nitride layer or the metal layer 102. A
silicon oxide film is formed by sputtering using silicon oxide
target to have a thickness of from 75 to 200 nm, here.
[0050] An optical filter 104 is next formed on the oxide layer 103.
As representative examples of the optical filter, a color filter, a
color conversion filter, a hologram color filter, and the like can
be cited.
[0051] As shown in FIG. 1B, a second substrate 112 for fixing the
optical filter 104 is next pasted with an adhesive material 111. As
for the adhesive material, various kinds of adhesive materials
including a reactive curing adhesive material, a thermal curing
adhesive material, a light curing adhesive material such as an
ultraviolet curing adhesive material, an anaerobic curing adhesive
material can be cited. As representative examples of these
materials, an organic resin such as an epoxy resin, an acrylic
resin, and a silicon resin can be cited.
[0052] The second substrate 112 is formed of a plastic substrate (a
film made from a high molecular weight material or a resin). As
representative examples of the plastic substrate, plastic
substrates made from polycarbonate (PC); ARTON formed of norbornene
resin with a polar group that is manufactured by JSR corporation;
polyethylene terephthalate (PET); polyether sulfone (PES);
polyethylene naphthalate (PEN); nylon; polyether ether ketone
(PEEK); polysulfone (PSF); polyetherimide (PEI); polyarylate (PAR);
polybutylene terephthalate (PBT); polyimide; and the like can be
used. Besides, an optical film such as a polarizing plate, a
retardation plate, and a light diffusing film can be used as the
second substrate.
[0053] Subsequently, as shown in FIG. 1C, a first support medium
121 is attached to the second substrate 112 with a peelable
adhesive agent 122. At this moment, when air bubbles intrude
between the second substrate 112 and the peelable adhesive agent
122, cracks are easily caused in the optical filter in the
subsequent separating step. In order to prevent cracking, the first
support medium is attached thereto so as not to intrude air bubbles
between the second substrate 112 and the peelable adhesive agent
122. Note that, the first support medium can be attached at short
times without intruding air bubbles therebetween by using a tape
mounter device and the like.
[0054] As the peelable adhesive agent 122, the followings can be
cited: a material formed of an adhesive material that is made from
an organic resin, typically, various kinds of peelable adhesives
including a reactive peeling adhesive, a thermal peeling adhesive,
a light peeling adhesive such as an ultraviolet ray peeling
adhesive, an anaerobic peeling adhesive, and the like; or a member
having adhesive layers formed of the various peelable adhesives on
each surface thereof (typically, a two-sided tape, and a two-sided
sheet).
[0055] It is preferable to use a substrate having higher rigidity
than that of the second substrate, typically, a glass substrate, a
quartz substrate, a metal substrate, or a ceramic substrate as the
first support medium.
[0056] Furthermore, it is preferable that a substrate having higher
rigidity than that of the first and second substrates be employed
as the first support medium.
[0057] In the case where the surface of the optical filter 104 is
uneven, a planarizing layer may be formed on the surface of the
optical filter as a buffer layer. Typically, an organic resin, an
organic or an inorganic insulating coating film, an insulating film
planarized by the CMP (chemical-mechanical polishing) technique and
the like, an adhesive, and the like can be cited. Note that, the
insulating film may have a single layer or a lamination structure.
Besides, the planarizing layer may be formed by using both the
insulating film and the adhesive.
[0058] In FIG. 1C, the first substrate 101 and the metal layer 102
formed thereon are referred to as a separation body 123. Meanwhile,
layers from the oxide layer 103 to the second substrate 112 (that
is, layers sandwiched between the metal layer 102 and the peelable
adhesive agent 122) are referred to as a subject body 124.
[0059] It is preferable that a support medium be bonded to the
first substrate 101 with a peelable adhesive agent so as to prevent
breakage of each substrate. By bonding the support medium thereto,
the separating step, that will be carried out later, can be
performed with a smaller force. Preferably, a substrate having
higher rigidity than that of the first substrate, typically, a
quartz substrate, a metal substrate, and a ceramic substrate are
used as the support medium.
[0060] As shown in FIG. 1D, a separation body 123 is next separated
from the subject body 124 by a physical means. For example, the
physical force indicates a relatively small force such as human
hands, gas pressure applied from a nozzle, and ultrasonic
waves.
[0061] As a result, separation is caused inside the metal layer
102, inside the metal oxide layer, in an interface between the
metal oxide layer and the oxide layer 103, or in an interface
between the metal oxide layer and the metal layer so that the
separation body 123 can be separated from the subject body 124 with
a relatively small force.
[0062] Note that, in order to separate the separation body easily,
a pretreatment is preferably carried out as a previous step prior
to the separating step. Typically, a treatment for partly reducing
the adhesiveness between the metal layer 102 and the oxide layer
103 is performed. The treatment for partly reducing the
adhesiveness therebetween is the one performed by partly
irradiating laser beam to the metal layer 102 along a rim of a
region to be separated, or the one performed by partly damaging
inside or an interface of the metal layer 102 by locally applying
pressure along a rim of a region to be separated from an external
portion. Specifically, a hard needle such as a diamond pen may
perpendicularly be pressed and moved while applying load
thereto.
[0063] Preferably, a scriber device can be used to move the hard
needle while applying the pressure with press force in the range of
from 0.1 mm to 2 mm. Thus, it is important to form a portion where
a separating phenomenon is easily caused, that is, a trigger of the
separating phenomenon, prior to performing the separating step. By
performing the pretreatment of selectively (partly) reducing the
adhesiveness in advance, poor separation can be prevented, thereby
improving the yield.
[0064] As illustrated in FIG. 1E, the peelable adhesive agent 122
and the first support medium 121 are next separated from the second
substrate 112.
[0065] According to the above-described steps, the optical film can
be formed. Namely, the optical filter 104 can be formed over the
second substrate 112.
[0066] Note that, the organic resin 111 that is an adhesive
material is interposed between the optical filter 104 and the
second substrate 112. Further, the oxide layer 103 is formed on a
surface of the optical filter 104; the surface is opposite to
another surface of the optical filter 104 on which organic resin is
formed.
[0067] Further, an optical film such as a polarizing plate, a
retardation plate, and a light diffusing film can be used as the
second substrate 112. In addition, a known antireflection film can
be formed on a surface of the second substrate or a surface of the
oxide layer. By employing the structure, an optical film having
plural functions can be formed.
[0068] The optical film manufactured in the embodiment mode has
flexibility, and hence, it can be provided on a portion or a
display device having a curved surface. Further, the optical filter
is not processed at high temperatures, thereby achieving an optical
filter having high reliability with high yield. Furthermore, the
optical filter having an excellent impact resistance property can
be formed.
[Embodiment Mode 2]
[0069] In the present embodiment mode, a method of manufacturing an
optical filter having a different adhesion surface between the
optical filter and the second substrate from that of Embodiment
Mode 1 will be described with reference to FIGS. 2A to 2E.
[0070] As shown in FIG. 2A, the metal layer 102 and the oxide layer
103 are sequentially laminated over the first substrate 101, and
the optical filter 104 is formed on the oxide layer 103 in the same
manner as Embodiment Mode 1. Note that, a metal oxide layer is
formed between the metal layer and the oxide layer.
[0071] As shown in FIG. 2B, a first support medium 121 is next
attached to the optical filter 104 with the peelable adhesive agent
122. The first substrate 101 and the metal layer 102 formed thereon
are referred to as a separation body 211, here. Further, the oxide
layer 103 and the optical filter 104 (i.e., layers sandwiched
between the metal layer 102 and the peelable adhesive agent 122)
are referred to as a subject body 212.
[0072] Note that, it is preferable that a support medium be
attached to the first substrate 101 with a peelable adhesive agent
so as to prevent breakage of each substrate. By attaching the
support medium thereto, the separating step, that will be performed
later, can be carried out with a smaller force. Preferably, the
support medium may be formed of a substrate having higher rigidity
than that of the first substrate, typically, a quartz substrate, a
metal substrate, and a ceramic substrate.
[0073] In the case where the surface of the optical filter 104 is
uneven, a planarizing layer may be formed on the surface of the
optical filter. By providing the planarizing layer, it is possible
to prevent atmospheric air from intruding between the optical
filter and the peelable adhesive agent, thereby improving the
reliability of the separating step. The planarizing layer can be
formed of a material that can be made by application such as an
insulating coating film and an organic resin. When the planarizing
layer is formed of a peelable material, typically, an adhesive, the
planarizing layer can be removed later.
[0074] As shown in FIG. 2C, the separation body 211 is next
separated from the subject body 212 by a physical means. In order
to separate easily, a pretreatment as described in Embodiment Mode
1 is preferably carried out as a previous step prior to the
separating step. According to the pretreatment, separation is
caused inside the metal oxide layer, in an interface between the
metal oxide layer and the oxide layer, or in an interface between
the metal oxide layer and the metal layer, thereby separating the
separation body 211 from the subject body 212 by a relatively small
force. Note that, the physical means mentioned in Embodiment Mode 1
is adapted.
[0075] As shown in FIG. 2D, the second substrate 112 is next
attached to the oxide layer 103 with the adhesive material 111.
Thereafter, the peelable adhesive agent 122 and the first support
medium 121 are separated from the optical filter 104.
[0076] According to the above-described steps, the optical film can
be formed. Namely, the optical filter 104 can be formed over the
second substrate 112.
[0077] Note that, the organic resin 111 that is an adhesive
material and the oxide layer 103 are interposed between the second
substrate 112 and the optical filter 104 that is formed in the
present embodiment mode.
[0078] Alternatively, the separating step may be carried out after
forming a transparent conductive film on the surface of the optical
filter 104. In accordance with the step, the optical film having a
pixel electrode can be formed.
[0079] Also, an optical film such as a polarizing plate, a
retardation plate, and a light diffusing film can be used as the
second substrate 112. In addition, a known antireflection film can
be formed on a surface of the second substrate or a surface of the
oxide layer. By employing the structure, an optical film having
plural functions can be formed.
[0080] The optical film manufactured in the embodiment mode has
flexibility, and therefore, it can be provided on a portion or a
display device having a curved surface. Further, the optical filter
is not processed at high temperatures, thereby achieving an optical
filter having high reliability with high yield. Furthermore, an
optical filter having an excellent impact resistance property can
be formed.
[Embodiment Mode 3]
[0081] With respect to Embodiment Mode 1 or Embodiment Mode 2, an
easier separating step in an interface between a separation body
and a subject body will be described in the present embodiment
mode.
[0082] After forming the metal layer 102 and the oxide layer 103
over the first substrate 101, the resultant first substrate is
heated. Thereafter, the optical filter 104 is formed on the oxide
layer. By performing the steps, separation can be caused between
the metal layer 102 and the oxide layer 103. At this moment, the
first substrate can be heated at temperature ranges that can be
withstood by the first substrate, typically, in a range of 100 to
600.degree. C., preferably, 150 to 500.degree. C.
[0083] As substitute for the step of the heat treatment, laser beam
may be irradiated from the side of the first substrate 101.
Further, a combined treatment of the laser irradiation and the heat
treatment may be carried out.
[0084] A continuous wave solid-state laser or a pulsed solid-state
laser can be used here. Typically, as the continuous wave
solid-state laser or the pulsed solid-state laser, one or more of
the following lasers can be used: a YAG laser; a YVO.sub.4 laser; a
YLF laser; a YAlO.sub.3 laser; a glass laser; a ruby laser; an
alexandrite laser; and a Ti:sapphire laser. Furthermore, as the
other continuous wave laser or pulsed laser, one or more of the
following lasers can be used: an excimer laser; an Ar laser; and a
Kr laser.
[0085] The laser beam can be irradiated to the metal layer from a
side of the substrate, or from a side of the oxide layer, or from
both sides of the substrate and the oxide layer.
[0086] Further, a beam shape of the laser beam may be a circular
shape, a triangular shape, a square shape, a polygonal shape, an
elliptical shape, or a linear shape. The size of the laser beam may
be in any sizes of microns, millimeters, and meters (that may also
have a doted shape or a planer shape). Furthermore, in the
above-mentioned oxidizing step, a region to be irradiated with the
laser beam may be overlapped with a region where has been
irradiated with the laser beam immediately before the
above-mentioned region, or may not be overlapped therewith. In
addition, it is preferable to use a laser beam having a wavelength
of from 10 nm to 1 mm, more preferably, from 100 nm to 10
.mu.m.
[0087] The optical film manufactured in the embodiment mode can be
separated from the first substrate with a smaller physical force,
thereby improving yield and its reliability.
[Embodiment Mode 4]
[0088] With respect to Embodiment Mode 1 or Embodiment Mode 2, an
easier separating step in an interface between a separation body
and a subject body will be described in the present embodiment
mode. In the embodiment mode, a heat treatment is performed after
forming an optical filter.
[0089] The metal layer 102 and the oxide layer 103 are formed over
the first substrate 101, the optical filter 104 is formed on the
oxide layer 103, and then the resultant first substrate is heated.
Thereafter, the second substrate 112 is attached to the optical
filter 104 with the adhesive material 111 in Embodiment Mode 1. On
the other hand, the first support medium 121 is attached to the
optical filter 104 by using the adhesive agent 122 in Embodiment
Mode 2.
[0090] As substitute for the above-mentioned steps, after forming
the metal layer 102 and the oxide layer 103 over the first
substrate 101, the resultant first substrate may be heated, and
subsequently, the optical filter 104 may be formed on the oxide
layer 103.
[0091] According to the steps, it is possible to separate the metal
layer 102 from the oxide layer 103 between the metal layer 102 and
the oxide layer 103 by a smaller physical means. At this moment,
the first substrate can be heated at temperature ranges that can be
withstood by the first substrate, typically, in a range of 100 to
300.degree. C., preferably, 150 to 250.degree. C.
[0092] In addition, as substitute for the step of the heat
treatment, laser beam may be irradiated from a side of the first
substrate 101 in the same manner as Embodiment Mode 3.
Alternatively, a combined treatment of laser irradiation and heat
treatment may be carried out. The optical film manufactured in the
embodiment mode can be separated from the first substrate with a
smaller physical force, thereby improving yield and its
reliability.
[Embodiment Mode 5]
[0093] A method of manufacturing an optical film through a
different step of forming a metal oxide film from Embodiment Mode 1
and Embodiment Mode 2 will be explained in the present embodiment
mode.
[0094] A metal layer 102 is formed over the first substrate 101 in
the same manner as Embodiment Mode 1 and Embodiment Mode 2. A metal
oxide layer is next formed on a surface of the metal layer 102. As
the method of forming the metal oxide layer, a thermal oxidation
treatment, an oxygen plasma treatment, a treatment with strong
oxidizing solution such as ozone water, and the like can be cited.
By using any one of the above-mentioned treatments, the surface of
the metal layer 102 is processed to form the metal oxide layer with
a thickness of from 1 to 10 nm, preferably, from 2 to 5 nm.
Thereafter, the oxide layer 103 and the optical filter 104 are
formed in the same manner as Embodiment Mode 1 or Embodiment Mode 2
so that the optical film is formed.
[0095] The metal oxide layer, which is a part of the separation
layer, can be formed in the present embodiment mode, thereby being
capable of forming the optical film with high yield.
[Embodiment 1]
[0096] An example of attaching an optical filter formed over a
glass substrate to a plastic substrate will be explained according
to the invention with reference to FIGS. 3A to 3E and FIGS. 4A to
4D. Although a color filter is used as a representative example of
the optical filter in the present embodiment, a color conversion
filter, a hologram color filter, and the like can be used in place
of the color filter.
[0097] As shown in FIG. 3A, a separation layer is formed over a
glass substrate (a first substrate 301). An AN100 is used as the
glass substrate in the embodiment. A metal layer 302, i.e., a
molybdenum film (with a thickness of from 10 to 200 nm, preferably,
from 50 to 75 nm) is formed on the glass substrate by sputtering.
Subsequently, an oxide film 303, i.e., a silicon oxide film (with a
thickness of from 10 to 400 nm, preferably, from 75 to 150 nm), is
laminated thereon. Upon laminating the oxide layer, a metal oxide
film (i.e., a molybdenum oxide film) is formed between the metal
layer 302 and the silicon oxide film 303. In the subsequent
separating step, separation is caused inside the molybdenum oxide
film; in an interface between the molybdenum oxide film and the
silicon oxide film; or in an interface between the molybdenum oxide
film and the molybdenum film.
[0098] As depicted in FIG. 3B, a color filter is formed on the
oxide layer 303. As a method of manufacturing the color filter, the
following known methods can be employed: an etching method using a
colored resin; a color resist method using color resist; a dyeing
method; an electrodeposition method; a micelle electrolytic method;
an electrodeposition transfer method; a film diffusion method; an
ink jet method (a droplet discharging method); a silver-salt
coloring method; and the like.
[0099] In the present, a color filter is formed by the etching
method using a photosensitive resin in which pigments are
dispersed. Firstly, a photosensitive acrylic resin in which black
pigments are dispersed is applied on the oxide layer 303 by
application. The acrylic resin is dried, baked preliminarily, and
then is exposed and developed. Thereafter, the acrylic resin is
heated at a temperature of 220.degree. C. to be cured so that a
black matrix 311 with a thickness of from 0.5 to 1.5 .mu.m is
formed. Subsequently, a photosensitive acrylic resin in which a red
pigment is dispersed, a photosensitive acrylic resin in which a
green pigment is dispersed, and a photosensitive acrylic resin in
which a blue pigment is dispersed are applied over the substrate by
application, respectively. Each photosensitive acrylic resin is
subjected to the same steps of forming the black matrix so that a
red colored layer 312 (hereinafter, referred to as a colored layer
R), a green colored layer 313 (hereinafter, referred to as a
colored layer G), and a blue colored layer 314 (hereinafter,
referred to as a colored layer B) are formed to have thicknesses of
from 1.0 to 2.5 .mu.m, respectively. Thereafter, a protective film
(not shown) is formed to complete a color filter 315. In the
present specification, the colored layer R represents a colored
layer that transmits red light (having the peak wavelength in the
vicinity of 650 nm) therethrough. The colored layer G represents a
colored layer that transmits green light (having the peak
wavelength in the vicinity of 550 nm) therethrough. Further, the
colored layer B represents a colored layer that transmits blue
light (having the peak wavelength in the vicinity of 450 nm)
therethrough.
[0100] As illustrated in FIG. 3C, a plastic substrate 322 is
attached to the color filter 315 with an adhesive material 321. As
for the adhesive material 321, an epoxy resin that is a light
curing adhesive material is employed. A polycarbonate film is used
as the plastic substrate 322.
[0101] Subsequently, as illustrated in FIG. 3D, a pretreatment is
performed to carry out a separating treatment easily. By using a
scriber device, a hard needle is moved while applying the pressure
with press force in the range of from 0.1 mm to 2 mm so as to
remove edges of the substrate. At this moment, separation is caused
between the metal layer 302 and the oxide layer 303. By reducing
the adhesiveness selectively (partly) in advance in the
pretreatment, poor separation can be prevented, thereby improving
the yield.
[0102] As shown in FIG. 3E, a first support medium 342 is attached
to the plastic substrate 322 by using a peelable adhesive agent
341. A two-sided tape is used as the peelable adhesive agent 341,
whereas a quartz substrate is used as the first support medium 342.
By attaching the first support medium to the plastic substrate,
crack and breakage of the color filter can be prevented.
[0103] Next, as shown in FIG. 4A, a second support medium 352 is
attached to the first substrate 301 by using a peelable adhesive
agent 351. A two-sided tape is used as the peelable adhesive agent,
whereas a quartz substrate is used as the second support medium
here as well as the first support medium.
[0104] As shown in FIG. 4B, the first substrate 301 is next
separated from the color filter 315. As illustrated in FIG. 3B, in
a portion where is subjected to the pretreatment in order to
perform the separating treatment easily, that is, in a region where
the adhesiveness between the metal layer 302 and the oxide layer
303 is partly reduced, the first substrate 301 with the metal layer
302 formed thereon and the second support medium 352 are separated
by a physical means. The separation can be performed by a
relatively small force (for example, load with use of a member,
human hands, gas pressure applied from a nozzle, and ultrasonic
waves, and the like). In the present embodiment, a part of a member
having a sharp end such as a wedge is inserted between the metal
layer 302 and the oxide layer 303 to separate the two layers. Thus,
the color filter 315 formed on the silicon oxide layer 303 can be
separated from the first substrate 301 and the metal layer 302.
[0105] Next, the first support medium 342 is separated from the
plastic substrate 322 as illustrated in FIG. 4C. If the adhesive
material remains on the plastic substrate, the residue of the
adhesive material might cause defects. Therefore, it is preferable
that the surface of the plastic substrate 322 be washed by O.sub.2
plasma irradiation, ultraviolet ray irradiation, or ozone cleaning.
In addition, vacuum heating may be performed so as to remove
adsorbed moisture on the plastic substrate.
[0106] According to the above-described steps, the color filter 315
is formed on the plastic substrate 322 while sandwiching the
organic material that is the adhesive material therebetween, as
shown in FIG. 4D. Note that, the oxide layer 303 is formed on the
surface of the color filter. The color filter 315, the oxide layer
303 formed on the surface of the color filter, the adhesive
material (resin layer) 321, and the plastic substrate 322 are
referred to as a substrate 361 having the color filter.
[0107] FIG. 9A shows a photograph of the substrate having the color
filter that is manufactured in the present embodiment. FIG. 9B is a
pattern diagram of FIG. 9A, wherein reference numeral 901 denotes a
hand; 902, a plastic substrate; and 903, a color filter. The
plastic substrate is curved since it has flexibility.
[0108] Note that, Embodiment Mode 2 is applicable to the present
embodiment in place of Embodiment Mode 1.
[0109] In accordance with the embodiment, a color filter can be
formed on a plastic substrate. Furthermore, by forming a color
filter on an optical film such as a polarizing plate, a retardation
plate, and a light diffusing film, an optical film integrated with
plural functions can be formed.
[0110] The plastic substrate having the color filter manufactured
according to the present embodiment has flexibility, and hence, it
can be provided on a portion or a display device having a curved
surface. Further, since the color filter is not processed at high
temperatures, the substrate having the color filter can be
manufactured so as to have high reliability with high yield.
Furthermore, the substrate having the color filter, that comprises
an excellent impact resistance property, can be formed.
[Embodiment 2]
[0111] In the present embodiment, an example of a light emitting
display device having the color filter manufactured in Embodiment 1
will be described with reference to FIGS. 5A and 5B.
[0112] A light emitting display device, which can emit light
downward, is illustrated in FIG. 5A. In FIG. 5A, reference numeral
501 denotes a layer with elements formed therein; 361, the
substrate having the color filter manufactured in Embodiment 1; and
500, a second substrate. In the layer with the elements formed
therein, a TFT 502 is formed as a semiconductor element over an
insulating film 520. The structure of the TFT 502 is not
particularly limited, and a top-gate TFT (typically, a planar TFT)
or a bottom-gate TFT (typically, an inverted stagger type TFT) may
be used. As for the elements, an organic semiconductor transistor,
a diode, or an MIM element can be used as substitute for the
TFT.
[0113] A first electrode made from a conductive oxide film is
connected to the TFT 502 as a pixel electrode. In the present
embodiment, the first electrode is used as an anode 503. A second
electrode is opposed to the first substrate while sandwiching a
layer containing a luminescent substance therebetween. The second
electrode is used as a cathode 505 here. The conductive oxide film
used here is transparent to visible light. Light generated in a
light emitting layer is extracted to outside (in a direction of
arrows in the drawing) through the anode 503. The TFT 502 and the
anode 503 are provided in each of a plurality of pixels.
[0114] A light emitting layer 504 is formed so as to be in contact
with the anode 503, and the cathode 505 is formed thereon. The
light emitting layer 504 corresponds to a light emitting portion of
a light emitting element, and is composed of a single layer or a
lamination layer. Basically, the light emitting layer comprising a
hole injecting layer, a hole transporting layer, an electron
injecting layer, and an electron transporting layer. Besides, the
light emitting layer may be composed of any known structures. As a
material for the light emitting layer, either an organic material
or an inorganic material can be used. In the case of using the
organic compound, either a high molecular weight organic material
or a low molecular weight organic material may be used.
[0115] The cathode is preferably made from a material having a low
work function, and a metal film containing an element that belongs
to the group 1 or 2 of the periodic table may be used. Of course,
any known cathode materials can be employed.
[0116] In the present specification, the light emitting element
indicates a light emitting element including an anode, a light
emitting layer, and a cathode. Therefore, a light emitting element
506 is composed of the anode 503, the light emitting layer 504, and
the cathode 505.
[0117] Since the anode 503 has a light transmitting property while
the cathode 505 has a light shielding property or a light
reflecting property, the light emitting element emits light toward
the anode, that is, toward the TFT (i.e., bottom emission, here).
Accordingly, the substrate 361 having the color filter, which is
formed in Embodiment 1, is attached to a surface through which
light is emitted, i.e., a surface of the insulating film 520 of the
layer 501 with elements formed therein, which is the TFT side of
the layer 501 with elements formed therein, by using an adhesive
material 508.
[0118] Meanwhile, the light emitting element 506 is covered with a
sealing material 507, and a second substrate 500 is attached to the
light emitting element with the sealing material 507. The sealing
material 507 is composed of a resin, and an ultraviolet curing
resin or an epoxy resin is typically used.
[0119] The second substrate 500 protects the light emitting element
506 from moisture and oxygen, and also functions as a protective
layer for protecting the light emitting element 506 from mechanical
shock. Although the second substrate 500 may be formed of any
materials, it is preferable that a plastic substrate be used so as
to reduce the weight of the light emitting display device and
enhance an impact resistance property. A polycarbonate (PC) film is
used as the plastic substrate in the present embodiment.
[0120] Steps of manufacturing the light emitting display device as
shown in FIG. 5A will be explained below.
[0121] The layer 501 with the elements formed therein that is
formed by a known method, is formed on a first substrate (not
illustrated in the drawing). The second substrate 500 is attached
to the layer 501 with the elements formed therein by using a
sealing material 507. Thereafter, the first substrate is removed
from the layer 501 with the elements formed therein. As a method of
removing the first substrate, a step of separating the first
substrate, a step of polishing the first substrate, a step of
melting the first substrate, and the like may properly be applied.
Note that, the first substrate may be polished thinly to use as the
second substrate. In the present embodiment, by utilizing the same
technique as Embodiment Mode 1 or Embodiment Mode 2, a metal layer,
an oxide layer, and the layer with elements formed therein are
sequentially laminated over the first substrate. Then, separation
is caused between the metal layer and the oxide layer to remove the
first substrate from the layer 501 with the elements formed
therein.
[0122] Next, the substrate 361 having the color filter manufactured
in Embodiment 1 is attached to the insulating film 520 of the layer
501 with the elements formed therein by using an adhesive material
508. Here, the insulating film 520 is formed on a surface through
which the light emitting element emits light, i.e., a surface of
the layer 501 with the elements formed, which is opposite to
another surface of the layer 501 with the elements formed therein
on which the second substrate 500 is formed. As representative
examples of the adhesive material 508, the ultraviolet curing resin
or the epoxy resin can be cited.
[0123] According to the steps above, the light emitting display
device using the plastic substrate and the color filter formed on
the plastic substrate (bottom emission type light emitting display
device) can be manufactured.
[0124] Next, a light emitting display device that can emit light
upward is shown in FIG. 5B.
[0125] In FIG. 5B, reference numeral 501 denotes the layer with the
elements formed therein; 361, the substrate having the color filter
manufactured in Embodiment 1; and 511, the second substrate.
[0126] The TFT 502 and the light emitting element 506 are formed in
the layer 501 with the elements formed therein as well as FIG. 5A.
With respect to the light emitting element, an anode comprises a
light shielding property or a light reflecting property, whereas a
cathode comprises a light transmitting property. Therefore, the
light emitting element as shown in FIG. 5B emits light toward the
cathode, that is, in the opposite direction of the TFT 502 (i.e.,
top-emission, here). The light emitting element 506 is covered with
the sealing material 507.
[0127] The substrate 361 having the color filter formed in
Embodiment 1 is attached to a side through which light is emitted,
i.e., a surface of the layer 501 with the elements formed therein,
which is opposite to another surface of the layer 501 with the
elements formed therein on which TFT is formed by using the sealing
material 507. The sealing material 507 is a resin, and the
ultraviolet curing resin or the epoxy resin is typically used. Note
that, an adhesive material may additionally be provided between the
sealing material 507 and the substrate 361 having the color
filter.
[0128] Meanwhile, at a side of the TFT of the layer with the
elements formed therein, i.e., a surface of the layer with the
elements formed therein, which is opposite to another surface of
the layer with the elements formed therein on which the substrate
361 having the color filter is formed, the insulating film 520 is
attached to the second substrate 511 by using the adhesive material
508.
[0129] Steps of manufacturing the light emitting display device
shown in FIG. 5B will be described below.
[0130] The layer 501 with the elements formed therein, which is
formed by a known method, is formed on a first substrate (not
illustrated in the drawing). The substrate 361 having the color
filter manufactured in Embodiment 1 is attached to the layer 501
with the elements formed therein by using the sealing material 507.
Thereafter, the first substrate is removed from the layer 501 with
the elements formed therein. As a method of removing the first
substrate, a step of separating the first substrate, a step of
polishing the first substrate, a step of melting the first
substrate, and the like may properly be adapted. Note that, the
first substrate may be polished thinly to remain. In the present
embodiment, by utilizing the same technique as Embodiment Mode 1 or
Embodiment Mode 2, a metal layer, an oxide layer, and the layer
with elements formed therein are sequentially laminated over the
first substrate. Then, separation is caused between the metal layer
and the oxide layer to remove the first substrate from the layer
501 with the elements formed therein
[0131] Subsequently, in the layer 501 with the elements formed
therein, the second substrate 511 is attached to the insulating
film 520 of the layer 501 with the elements formed therein, i.e., a
surface of the layer 501 with the elements formed therein, which is
opposed to another surface of the layer 501 with the elements
formed therein on which substrate 361 having the color filter is
formed, by using the adhesive material 508. As representative
examples of the adhesive material 321, the ultraviolet curing resin
or the epoxy resin can be cited.
[0132] According to the above-mentioned steps, the light emitting
device using the plastic substrate and the color filter formed over
the plastic substrate (top-emission type light emitting display
device) can be manufactured.
[0133] Note that, it is preferable to use colored layers of the
color filter for the light emitting display device each of which
has low pigment content so as to obtain a large amounts of light.
Alternatively, the amount of light can be increased by making the
film thickness of each colored layer thin. Also, when a black
pigment is doped in the colored layers, such a defect that an
observer is reflected in a cathode can be prevented by absorbing
outside light entered from the outside of the light emitting
display device.
[0134] Further, an antireflection film may be provided on the
surface of the substrate 361 having the color filter. The
antireflection film is a single layer film or a lamination film
having a condition in which reflected light is hardly caused by
controlling a refractive index and a film thickness. A known
antireflection film can be used.
[0135] Further, a polarizing plate or a circular polarizing plate
(including a circular polarizing film) may be used instead of the
plastic substrate 322.
[0136] Although examples in which the light emitting element emits
light in only one direction are shown in the embodiment, the
present invention is not limited thereto. The present invention can
be applied to a light emitting element, which can emit light in two
directions (that is, a light emitting element in that both of an
anode and a cathode comprise the light transmitting properties,
i.e., a dual-emission type light emitting element). In this case,
the layer with the elements formed therein may be interposed
between two substrates having color filters.
[0137] Although the present embodiment shows the light emitting
element driven by an active matrix driving method, wherein TFTs are
formed in each pixel electrode, the present embodiment is not
limited thereto. A light emitting element driven by a passive
matrix driving method may be used properly.
[0138] In addition, a light emitting display device may be formed
by using an organic semiconductor transistor as an element provided
in each pixel electrode, and a plastic substrate as the first
substrate. In this case, the step of removing the first substrate
can be omitted, thereby increasing throughput.
[0139] One feature of the light emitting display devices described
in this embodiment is that the layer with the elements formed
therein and the color filter are formed individually in the
separating steps, and then both are attached to each other after
being completed. By taking such a structure, the yield of the layer
with the elements, i.e., the TFT and the light emitting element,
formed therein, and the yield of the color filter can be controlled
individually, which suppresses decline in the yield of the entire
light emitting display device.
[0140] Furthermore, the steps of manufacturing an active matrix
substrate and the steps of manufacturing a color filter can be
simultaneously run, thereby reducing manufacturing lead time of the
light emitting display device. By utilizing a plastic substrate, a
light emitting display device having reduced weight with an
improved impact resistance property can be manufactured.
[Embodiment 3]
[0141] An example of a liquid crystal display device having the
color filter manufactured in Embodiment 1 will be explained in the
present embodiment.
[0142] In FIG. 6A, reference numeral 601 denotes a layer with
elements formed therein; 361, the substrate having the color filter
manufactured in Embodiment 1; and 500, a second substrate.
[0143] A TFT 502 as semiconductor element and a layer to be filled
with a liquid crystal later are formed in the layer 601 with the
elements formed therein in the same manner as Embodiment 2. A
structure of the TFT 502 is not particularly limited, and either a
top-gate TFT (typically, a planar TFT) or a bottom-gate TFT
(typically, a inverted stagger type TFT) may be used. As substitute
for the TFT, an organic semiconductor transistor, a diode, and an
MIM element can be used as the element.
[0144] A first electrode 602 made from a conductive oxide film is
connected to the TFT 502 as a pixel electrode. The conductive oxide
film used here is transparent to visible light, and light emitted
from an external backlight is extracted to outside through the
first electrode 602. The TFT 502 and the first electrode 602 are
provided in each of a plurality of pixels.
[0145] An alignment film 603 is formed on the first electrode 602.
An alignment film that is formed by rubbing polyimide is used in
the present embodiment. Besides, an alignment film formed by the
oblique deposition with use of silicon oxide, or a photo-alignment
film can be used as the alignment film.
[0146] A second electrode 606 and an alignment film 605 formed in
the same step as the alignment film 603 are formed over the second
substrate 500.
[0147] The alignment film 605 formed over the second substrate 500
and the layer 601 with the elements formed therein are attached to
each other with a sealing material (not shown in the drawing).
[0148] A substrate 608 having a color filter is attached to a
surface of an insulating film 520 of the layer 601 with the
elements formed therein by using an adhesive material 607.
[0149] Steps of manufacturing the liquid crystal display device as
shown in FIG. 6A will hereinafter be explained.
[0150] The second electrode 606 made from the conductive oxide film
is formed on the second substrate 500. Thereafter, the alignment
film 605 is formed on the surface of the second electrode.
[0151] The layer 601 with the elements formed therein is formed on
a first substrate (not shown in the drawing) by a known method. The
second substrate 500 is attached to the layer 601 with the elements
formed therein by using a first sealing material. In this case, the
second substrate is attached thereto so that the alignment film 603
formed on the surface of the layer 601 with the elements formed
therein and the alignment film 605 formed over the second substrate
are faced to each other. Further, a spacer is formed between the
two substrates. The first sealing material is mixed with filler
such that the two substrates are attached to each other while
maintaining an even distance therebetween with the spacer and the
filler.
[0152] Thereafter, the first substrate is removed from the layer
601 with the elements formed therein. The known techniques as
disclosed in Embodiment 2 can be adapted to the step of removing
the first substrate. In this embodiment, by utilizing a same
technique as Embodiment Mode 1 or Embodiment Mode 2, a metal layer,
an oxide layer, and the layer with the elements formed therein are
sequentially laminated over the first substrate. Then, separation
is caused between the metal layer and the oxide layer to remove the
first substrate from the layer 601 with the elements formed
therein.
[0153] Subsequently, the substrate 361 having the color filter and
the insulating film 520 of the layer 601 with the elements formed
therein are attached to each other with the adhesive material
607.
[0154] A liquid crystal material 604 is injected between the two
substrates, that is, in the layer 601 with the elements formed
therein, and the two substrates are completely sealed with a second
sealing material (not illustrated in the drawing).
[0155] According to the above-mentioned steps, the liquid crystal
display device using the plastic substrate and the color filter
formed over the plastic substrate can be manufactured.
[0156] Next, in FIG. 6B, reference numeral 601 denotes a layer with
elements formed therein; 608, a substrate having a color filter;
and 511, a second substrate.
[0157] The second substrate 511 and an insulating film 520 of the
layer 601 with the elements formed therein are attached to each
other with an adhesive material 607 composed of an organic
resin.
[0158] The layer 601 with the elements formed therein is adhered
with the substrate 608 having the color filter by a sealing
material (not illustrated in the drawing).
[0159] The substrate 608 having the color filter is formed in
accordance with Embodiment Mode 2. Specifically, an adhesive
material 610 comprising organic resin and an oxide layer 303 are
laminated over a plastic substrate 322. A black matrix 311, a red
colored layer 312, a green colored layer 313, and a blue colored
layer 314 are aligned on the oxide layer and an overcoat layer for
covering the layers is formed thereon so as to form the color
filter. A second electrode 606 is formed over a surface of the
color filter, and an alignment film 605 is formed thereon. Note
that, it is possible to use a substrate having the color filter in
which the second electrode 606 and the alignment film 605 are
formed over a surface of the oxide layer 303 of the substrate 361
having the color filter as disclosed in Embodiment 1.
[0160] Steps of manufacturing the liquid crystal display device as
shown in FIG. 6B will be described below.
[0161] The layer 601 with the elements formed therein is formed on
a first substrate (not shown in the drawing) by a known method. The
substrate 608 having the color filter is attached to the layer 601
with the elements formed therein by using a first sealing material
(not illustrated in the drawing). In this case, the substrate 608
having the color filter is attached thereto so that the alignment
film 603 formed on the surface of the layer 601 with the elements
formed therein and the alignment film 605 formed on the substrate
having the color filter are faced to each other. Further, a spacer
is formed between the two substrates. The first sealing material is
mixed with filler so that the two substrates are attached to each
other while maintaining an even distance therebetween with the
spacer and the filler.
[0162] Thereafter, the first substrate is removed from the layer
601 with the elements formed therein. The known techniques as
disclosed in Embodiment 2 can be applied to the step of removing
the first substrate. In this embodiment, by utilizing the same
technique as Embodiment Mode 1 or Embodiment Mode 2, a metal layer,
an oxide layer, and the layer with the elements formed therein are
sequentially laminated over the first substrate. Then, separation
is caused between the metal layer and the oxide layer to remove the
first substrate from the layer 601 with the elements formed
therein.
[0163] Subsequently, the second substrate 511 and the insulating
film 520 of the layer 601 with the elements formed therein are
attached to each other with an adhesive material 607.
[0164] A liquid crystal material 604 is injected between the two
substrates, that is, in the layer 601 with the elements formed
therein, and the two substrates are completely sealed with a second
sealing material (not illustrated in the drawing).
[0165] According to the above-mentioned steps, the liquid crystal
display device using the plastic substrate and the color filter
formed over the plastic substrate can be manufactured as shown in
FIG. 6B.
[0166] Note that, it is preferable that the color filter used in
the liquid crystal display device has a sharp peak wave length.
Also, when a black pigment is doped in colored layers, such a
defect that an observer is reflected in a cathode can be prevented
by absorbing outside light entered from the outside of the light
emitting display device.
[0167] Further, an antireflection film may be provided on each
surface of the substrates 361 and 608 having the color filters. The
antireflection film is a single layer film or a lamination film
having a condition in which reflected light is hardly caused by
controlling a refractive index and a film thickness. A known
antireflection film can be used.
[0168] Further, a polarizing plate and a circular polarizing plate
(including a circular polarizing film) may be used instead of the
plastic substrate 322.
[0169] Although the present embodiment shows a liquid crystal
element driven by an active matrix driving method, wherein TFTs are
provided in each pixel electrode, the present embodiment is not
limited thereto. A liquid crystal element driven by a passive
matrix driving method can also be used, properly.
[0170] In addition, the liquid crystal display device may be formed
by using an organic semiconductor transistor as the elements formed
in each pixel electrode, and a plastic substrate as the first
substrate. In this case, the step of removing the first substrate
can be omitted, thereby increasing throughput.
[0171] One feature of the liquid crystal display device described
in this embodiment is that the layer with the elements formed
therein and the color filter are formed individually in the
separating steps, and then both are attached to each other after
being completed. By taking such a structure, the yield of the layer
with the elements, i.e., the TFT and the liquid crystal element,
formed therein and the yield of the color filter can be controlled
individually, which suppresses decline in the yield of the entire
liquid crystal display device.
[0172] Furthermore, the steps of manufacturing an active matrix
substrate and the steps of manufacturing a color filter can be
simultaneously run, thereby reducing manufacturing lead time of the
entire liquid crystal display device.
[0173] By utilizing a plastic substrate, a liquid crystal display
device having reduced weight with an improved impact resistance
property can be manufactured.
[Embodiment 4]
[0174] In the present embodiment, an exterior appearance of a panel
corresponding to one embodiment of a display device will be
explained with reference to FIGS. 7A and 7B. FIG. 7A shows a top
view of a panel in which a layer 501 with elements formed therein
(concretely, a TFT and a light emitting element) is encapsulated
between a color filter and a second substrate by using a sealing
material. FIG. 7B corresponds to a cross sectional view taken along
a line A-A' of FIG. 7A.
[0175] Reference numeral 1201 denoted by a doted line is a signal
line driver circuit; 1202, a pixel portion; and 1203, a scanning
line driver circuit in FIG. 7A. Further, reference numeral 1204
denotes a second substrate and reference numeral 1205 denotes a
first sealing material that contains a gap material for maintaining
a gap of an enclosed space. The inside surrounded by the sealing
material 1205 is filled with a second sealing material. As the
first sealing material, an epoxy resin containing filler with high
viscosity is preferably used. As the second sealing material, epoxy
resin having high light transmitting property with low viscosity is
preferably used. Further, it is desirable that the sealing
materials 1205 and 1207 be materials that do not transmit moisture
and oxygen as much as possible.
[0176] In a connection region 1210, reference numeral 1208 denotes
a connection wiring for transmitting signals inputted in the signal
line driver circuit 1201 and the scanning line driver circuit 1203,
and receives a video signal and a clock signal from an FPC
(flexible printed circuit) 1209 that becomes an external input
terminal.
[0177] Next, a cross sectional structure will be described
referring to FIG. 7B. A driver circuit and a pixel portion are
formed over the first substrate 322. As the substrate 361 having
the color filter, a color filter is provided on the first substrate
322. The signal line driver circuit 1201 as the driver circuit, and
the pixel portion 1202 are shown here. A CMOS circuit composed by
combining an n-channel TFT 1223 and a p-channel 1224 is formed as
the signal line driver circuit 1201.
[0178] The pixel portion 1202 is composed of a plurality of pixels
including a switching TFT 1211, a current controlling TFT 1212, and
a first electrode (anode) 1213 made from a transparent conductive
film, which is electrically connected to a drain of the current
controlling TFT 1212.
[0179] An interlayer insulating film 1220 of these TFTs 1211, 1212,
1223, and 1224 may be formed of a material containing an inorganic
material (such as silicon oxide, silicon nitride, and silicon
oxynitride); or an organic material (such as polyimide, polyamide,
polyimide amide, benzocyclobutene, and siloxane polymer) as its
principal constituent. When siloxane polymer is used as a raw
material of the interlayer insulating film, an insulating film
having a skeleton structure of silicon and oxygen and including
hydrogen or/and alkyl group in a side chain is formed.
[0180] The first electrode 1213 is connected to the connection
electrode so as to overlap each other, and is electrically
connected to a drain region of the TFTs via the connection
electrode. It is preferable that the first electrode 1213 have
transparency and be formed of a conductive film having a high work
function (such as ITO (indium oxide-tin oxide alloy), indium
oxide-zinc oxide alloy (In.sub.2O.sub.3--ZnO), and zinc oxide
(ZnO)).
[0181] An insulator 1214 (referred to as a bank, a partition wall,
a barrier, an embankment, etc.) is formed on each end of the first
electrode (anode) 1213. To improve coverage of a film formed on the
insulator 1214, an upper edge portion or a lower edge portion of
the insulator 1214 is formed to have a curved face having a radius
of curvature. Further, the insulator 1214 may be covered with a
protective film made from an aluminum nitride film, an aluminum
nitride oxide film, a thin film containing carbon as its principal
constituent, or a silicon nitride film. An organic compound
material is vapor deposited on the first electrode (anode) 1213 to
form a layer 1215 containing a luminescent substance
selectively.
[0182] To remove gases contained in the substrate prior to
performing the vapor deposition of the material for the layer
containing the luminescent substance, a heat treatment at a
temperature of 200 to 300.degree. C. is desirably carried out under
a reduced pressure atmosphere or an inert atmosphere.
[0183] In order to make the layer 1215 containing the luminescent
substance emits white light, for example, white light emission can
be achieved by sequentially laminating Alq.sub.3, Alq.sub.3
partially doped with Nile red, which is a red light emitting
pigment, p-EtTAZ, and TPD (aromatic diamine) by using vapor
deposition. Further, when an EL layer is formed by application
using spin coating, it is preferable to bake the layer by vacuum
heating after its application. For example, an aqueous solution of
poly(ethylene dioxythiophene)/poly(styrene sulfonic acid)
(PEDOT/PSS), which functions as a hole injecting layer, may be
applied over the entire surface of the substrate and baked.
Subsequently, a solution of polyvinyl carbazole (PVK) doped with a
pigment for luminescence center (such as
1,1,4,4-tetraphenyl-1,3-butadiene (TPB),
4-dicyanomethylene-2-methyl-6-(p-dimethylamino-styryl)-4H-pyran
(DCM1), Nile red, and coumarin 6), which serves as a light-emitting
layer, may then be applied over the entire surface and baked.
[0184] The layer 1215 containing the luminescent substance may be
formed to have a single layer. In this case, 1,3,4-oxadiazole
derivative (PBD), which has electron transporting properties, may
be dispersed in polyvinyl carbazole (PVK), which has hole
transporting properties. In addition, white light emission can also
be, obtained by dispersing 30 wt % of PBD as an electron
transporting agent and dispersing a suitable amount of four kinds
of pigments (TPB, coumarin 6, DCM1, and Nile red). In addition to
the above-mentioned light emitting element that emit white light, a
light emitting element that emit red light, green light, or blue
light can be manufactured by properly selecting the material of the
layer 1215 containing the luminescent substance.
[0185] Further, triplet excited luminescent materials including
metal complexes and the like may be used for the layer 1215
containing the luminescent substance instead of the above-mentioned
singlet excited luminescent materials. That is, the layer 1215
containing the luminescent substance may includes pixels emitting
red light, pixels emitting green light, and pixels emitting blue
light, wherein the pixels emitting red light contain the triplet
excited luminescent material or the singlet excited luminescent
material, the pixels emitting green light contain the triplet
excited luminescent material, and the pixels emitting blue light
contains the singlet excited luminescent material.
[0186] As a material for the second electrode (cathode) 1216, a
material having a low work function (Al, Ag, Li, Ca; alloy of these
such as MgAg, MgIn, AlLi, CaF.sub.2, and CaN) may be used.
[0187] Thus, a light emitting element 1218 composed of the first
electrode (anode) 1213, the layer 1215 containing the luminescent
substance, and the second electrode (cathode) 1216 can be formed.
The light emitting element 1218 emits light in a direction of an
arrow shown in FIG. 7B. The light emitting element 1218 is one of
light emitting elements that emit white light. A full color display
can be performed by transmitting light emitted from the light
emitting element 1218 through the color filter. Alternatively, when
the light emitting element 1218 is one of light emitting elements
that emit monochromatic light of R, G; or B, three light emitting
elements having layers containing organic compounds, which emit R,
and B lights respectively, are selectively used, thereby performing
a full color display. In this case, a light emitting display device
with high color purity can be obtained by aligning of respective
colored layers of red, green, and blue for the color filter and the
light emitting elements for each luminescent color.
[0188] A protective layer 1217 is formed to encapsulate the light
emitting element 1218. The protective layer is composed by
laminating a first inorganic insulating film, a stress relaxation
film, and a second inorganic insulating film.
[0189] In the embodiment, the substrate 361 having the color filter
is attached to the layer 501 with the elements formed therein by
the adhesive material 508 as shown in FIG. 5A of Embodiment 2. Note
that, the color filter may be used as the second substrate, and the
plastic substrate may be used as the first substrate as shown in
FIG. 5B of Embodiment 2.
[0190] Although the scanning line driver circuit formed by using
the TFTs is shown here, the prevent embodiment is not limited to
the structure. Alternatively, a scanning line driver circuit and a
signal line driver circuit may be formed of transistors using a
single-crystal semiconductor, and attached.
[0191] One feature of the light emitting display device described
in this embodiment is that the layer with the elements formed
therein and the color filter are formed individually in the
separating steps, and then both are attached to each other after
being completed. By taking such a structure, the yield of the layer
with the elements, i.e., the TFT and the light emitting element,
formed therein, and the yield of the color filter can be
individually controlled, thereby suppressing decline in the yield
of the entire light emitting display device.
[0192] Furthermore, the steps of manufacturing an active matrix
substrate and the steps of manufacturing a color filter can be
simultaneously run, thereby reducing manufacturing lead time of the
light emitting display device.
[0193] By utilizing a plastic substrate, a light emitting display
device having reduced weight with an improved impact resistance
property can be manufactured.
[Embodiment 5]
[0194] In the present embodiment, an exterior appearance of a panel
corresponding to one embodiment of a display device of the
invention will be explained with reference to FIGS. 8A and 8B. FIG.
8A shows a top view of a panel in which a layer 601 with elements
formed therein (concretely, a TFT and a liquid crystal layer) is
encapsulated between a substrate 361 having a color filter and a
second substrate 1204 by using a sealing material 1205. FIG. 8B
corresponds to a cross sectional view taken along a line A-A' of
FIG. 8A.
[0195] In FIG. 8A, reference numeral 1201 denoted by a doted line
is a signal line driver circuit; 1202, a pixel portion; and 1203, a
scanning line driver circuit. Further, reference numeral 322
denotes a first substrate and reference numeral 1204 denotes a
second substrate, and reference numerals 1205 and 1207 denote a
first sealing material and a second sealing material, respectively,
that contain a gap material for maintaining a gap of an enclosed
space. A layer in which semiconductor elements, typically, TFTs
1223, 1224, and 1311 are formed, is attached to the first substrate
by using an adhesive material 607. The first substrate 322 and the
second substrate 1204, that is, the layer with the elements formed
therein and the second substrate are sealed with a sealing material
1205, and a liquid crystal is filled therebetween.
[0196] Next, a cross sectional structure will be described
referring to FIG. 8B. A driver circuit and a pixel portion are
formed over the first substrate 322, which includes a plurality of
semiconductor elements represented by the TFT s. As the substrate
361 having the color filter, a color filter is provided on the
first substrate 322. The signal line driver circuit 1201 as a
driver circuit and the pixel portion 1202 are shown here. A CMOS
circuit composed by combining an n-channel TFT 1223 and a p-channel
TFT 1224 is formed as the signal line driver circuit 1201.
[0197] The first electrode 1313 of a liquid crystal element 1315 is
electrically connected to the TFT 1311 via a wiring 1312. A second
electrode 1316 of the liquid crystal element 1315 is formed on the
second substrate 1204. A portion overlapped with the first
electrode 1313, the second electrode 1316, and the liquid crystal
1314 corresponds to the light crystal element 1315.
[0198] Reference numeral 1318 denotes a spherical spacer, which is
provided for controlling a distance (cell gap) between the first
electrode 1313 and the second electrode 1316. A spacer that is
formed by etching an insulating film into a predetermined shape may
be used instead. Various kinds of signals and voltage supplied to
the scanning line driver circuit 1203 or the pixel portion 1202 are
supplied from an FPC 1209 via a connection wiring 1208.
[0199] In the present embodiment, the substrate 361 having the
color filter is attached to the layer 601 with the elements formed
therein by using an adhesive material 607 as illustrated in FIG. 6A
of Embodiment 3. Note that, the color filter may be used as the
second substrate, whereas the plastic substrate may be used as the
first substrate in the same manner as FIG. 6B of Embodiment 3.
[0200] Although the scanning line driver circuit formed by using
the TFTs is shown here, the prevent embodiment is not limited to
the structure. Alternatively, a scanning line driver circuit and a
signal line driver circuit may be formed of transistors using a
single-crystal semiconductor, and attached.
[0201] One feature of the liquid crystal display device described
in this embodiment is that the layer with the elements formed
therein and the color filter are formed individually in the
separating steps, and then both are attached to each other after
being completed. By taking such a structure, the yield of the layer
with the elements, i.e., the TFT and the light emitting element,
formed therein and the yield of the color filter can be
individually controlled, thereby suppressing decline in the yield
of the entire liquid crystal display device.
[0202] Furthermore, the steps of manufacturing an active matrix
substrate and the steps of manufacturing a color filter can be
simultaneously run, thereby reducing manufacturing lead time for
the liquid crystal display device.
[0203] By utilizing a plastic substrate, a liquid crystal display
device having reduced weight with an improved impact resistance
property can be manufactured.
[Embodiment 6]
[0204] Various kinds of electronic appliances can be manufactured
by incorporating display devices obtained according to the
invention. Examples of the electronic appliances include: a TV set;
a video camera; a digital camera; a goggle type display (a
head-mounted display); a navigation system; an audio reproduction
device (such as a car audio and an audio component system); a
personal laptop computer; a game machine; a portable information
terminal (such as a mobile computer, a cellular telephone, a
portable game machine, and an electronic book); an image
reproduction device provided with a recording medium (typically, a
device which can reproduce the recording medium such as a DVD
(digital versatile disc) and display images thereof); and the like.
As representative examples of these electronic appliances, a
television, a personal laptop computer, and an image reproduction
device provided with a recording medium will be illustrated in
FIGS. 10A to 10C.
[0205] FIG. 10A is a television including a casing 2001; a
supporting base 2002; a display portion 2003; a speaker portion
2004; a video input terminal 2005; and the like. The present
invention can be applied to the display portion 2003. The
television includes every television for displaying information
such as one for a personal computer, for receiving TV broadcasting,
and for advertisement. By implementing the present invention, a
television having a thin and lightweight display portion can be
manufactured.
[0206] FIG. 10B is a personal laptop computer including a main body
2201; a casing 2202; a display portion 2203; a keyboard 2204; an
external connection port 2205; a pointing mouse 2206; and the like.
The present invention can be applied to the display portion 2203.
By implementing the present invention, a thin and lightweight
personal laptop computer can be manufactured.
[0207] FIG. 10C is a portable image reproduction device provided
with a recording medium (specifically, a DVD player), including a
main body 2401; a casing 2402; a display portion A 2403; a display
portion B 2404; a recording medium (such as a DVD) reading portion
2405; operation keys 2406; a speaker portion 2407; and the like.
The display portion A 2403 mainly displays image information
whereas the display portion B 2404 mainly displays character
information. The present invention can be applied to both the
display portion A 2403 and the display portion B 2404. Note that
the image reproduction device provided with the recording medium
includes a domestic game machine and the like. By implementing the
present invention, a thin and lightweight portable image
reproduction device equipped with the recording medium can be
manufactured.
* * * * *