U.S. patent application number 10/254767 was filed with the patent office on 2003-04-03 for color filter substrate and method of fabricating the same.
This patent application is currently assigned to LG.Philips LCD Co., Ltd.. Invention is credited to Lee, Yun-Bok, Yi, Jong-Hoon.
Application Number | 20030062532 10/254767 |
Document ID | / |
Family ID | 19714805 |
Filed Date | 2003-04-03 |
United States Patent
Application |
20030062532 |
Kind Code |
A1 |
Lee, Yun-Bok ; et
al. |
April 3, 2003 |
Color filter substrate and method of fabricating the same
Abstract
A color filter substrate for a liquid crystal display device
includes a polarizing substrate, a black matrix positioned on the
polarizing substrate, a color filter layer positioned on the black
matrix, and a common electrode positioned on the color filter
layer.
Inventors: |
Lee, Yun-Bok; (Seoul,
KR) ; Yi, Jong-Hoon; (Seoul, KR) |
Correspondence
Address: |
MORGAN LEWIS & BOCKIUS LLP
1111 PENNSYLVANIA AVENUE NW
WASHINGTON
DC
20004
US
|
Assignee: |
LG.Philips LCD Co., Ltd.
|
Family ID: |
19714805 |
Appl. No.: |
10/254767 |
Filed: |
September 26, 2002 |
Current U.S.
Class: |
257/89 |
Current CPC
Class: |
G02F 1/133305 20130101;
G02F 1/133514 20130101; G02F 1/133528 20130101 |
Class at
Publication: |
257/89 |
International
Class: |
H01L 033/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 28, 2001 |
KR |
2001-60618 |
Claims
What is claimed is:
1. A color filter substrate for a liquid crystal display device,
comprising: a polarizing substrate; a black matrix positioned on
the polarizing substrate; a color filter layer positioned on the
black matrix; and a common electrode positioned on the color filter
layer.
2. The color filter substrate according to claim 1, wherein the
polarizing substrate functions as a polarizer.
3. The color filter substrate according to claim 1, wherein the
polarizing substrate includes a plastic material.
4. The color filter substrate according to claim 3, wherein the
polarizing substrate includes a polyvinyl alcohol material.
5. The color filter substrate according to claim 1, wherein the
color filter layer is formed by a thermal transfer method.
6. The color filter substrate according to claim 5, further
comprising an adhesive layer disposed between the polarizing
substrate and the color filter layer.
7. The color filter substrate according to claim 1, wherein the
color filter layer includes three sub-color filters of red, green,
and blue.
8. The color filter substrate according to claim 1, wherein the
black matrix is formed by a thermal transfer method.
9. The color filter substrate according to claim 8, further
comprising an adhesive layer disposed between the polarizing
substrate and the black matrix.
10. The color filter substrate according to claim 8, wherein the
black matrix includes a black resin material.
11. The color filter substrate according to claim 10, wherein the
black resin material includes carbon.
12. The color filter substrate according to claim 1, further
comprising an alignment layer on the common electrode.
13. A method of fabricating a color filter substrate for a liquid
crystal display device, comprising steps of: forming a black matrix
on a polarizing substrate; forming a color filter layer on the
black matrix; and forming a common electrode on the color filter
layer.
14. The method according to claim 13, wherein the polarizing
substrate functions as a polarizer.
15. The method according to claim 13, wherein the polarizing
substrate includes a plastic material.
16. The method according to claim 13, wherein the step of forming a
color filter layer includes: aligning a first transcription film
having a first color filter layer, a light-to-heat conversion
layer, and a supporting film, sequentially formed on the polarizing
substrate including the black matrix; performing a first thermal
transfer process on a first portion of the first transcription
film; and removing the first transcription film except for the
first portion where the first thermal transfer process is
performed.
17. The method according to claim 16, wherein the step of
performing a first thermal transfer process includes irradiating a
laser beam onto the first transcription film.
18. The method according to claim 16, further comprising steps of
aligning a second transcription film having a second color filter
layer, performing a second thermal transfer process on a second
portion of the second transcription film, and removing the second
transcription film except for the second portion where the second
thermal transfer process is performed.
19. The method according to claim 18, wherein the step of
performing a second thermal transfer process includes irradiating a
laser beam onto the second transcription film.
20. The method according to claim 18, further comprising steps of
aligning a third transcription film having a third color filter
layer, performing a third thermal transfer process on a third
portion of the third transcription film, and removing the third
transcription film except for the third portion where the third
thermal transfer process is performed.
21. The method according to claim 20, wherein the step of
performing a third thermal transfer process includes irradiating a
laser beam onto the third transcription film.
22. The method according to claim 16, wherein the first
transcription film includes an adhesive layer on a side of the
first color filter layer facing the polarizing substrate.
23. The method according to claim 13, wherein the step of forming a
black matrix includes: aligning a transcription film having a black
resin layer, a light-to-heat conversion layer, and a supporting
film, sequentially formed onto the polarizing substrate;
selectively performing a thermal transfer process on a first
portion of the transcription film; and removing the transcription
film except for the first portion where the thermal transfer
process is performed.
24. The method according to claim 23, wherein the black resin layer
includes carbon.
25. The method according to claim 23, wherein the transcription
film includes an adhesive layer on a side of the black resin layer
facing the polarizing substrate.
26. The method according to the claim 13, further comprising
forming an alignment layer on the common electrode.
27. A method of fabricating a color filter substrate for a liquid
crystal display device, comprising steps of: aligning a first
transcription film having a black resin layer, a first
light-to-heat conversion layer, and a first supporting film,
sequentially formed onto a polarizing substrate; selectively
performing a first thermal transfer process on a first portion of
the first transcription film; removing the first transcription film
except for the first portion where the first thermal transfer
process is performed to form a black matrix on the polarizing
substrate; aligning a second transcription film having a color
filter layer, a second light-to-heat conversion layer, and a second
supporting film, sequentially formed onto the polarizing substrate
including the black matrix; selectively performing a second thermal
transfer process on a first portion of the second transcription
film; removing the second transcription film except for the first
portion of the second transcription film where the second thermal
transfer process is performed to form a color filter on the
polarizing substrate including the black matrix; and forming a
common electrode on the color filter.
Description
[0001] The present invention claims the benefit of Korean Patent
Application No. P2001-060618 filed in Korea on Sep. 28, 2001, which
is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a liquid crystal display
device substrate, and more particularly, to a color filter
substrate and method of fabricating a color filter substrate for a
liquid crystal display device.
[0004] 2. Discussion of the Related Art
[0005] In general, a liquid crystal display (LCD) device includes
upper and lower substrates with a liquid crystal material layer
disposed therebetween. One of the upper or lower substrates
commonly includes a color filter layer for displaying color images.
The color filter layer may commonly include sub-color filters of
red (R), green (G), and blue (B). The color filter layer is formed
by various methods including a dyeing method, an electro-deposition
method, a pigment dispersion method, and a printing method, for
example. In general, the pigment dispersion method is commonly used
because it forms a fine pattern.
[0006] FIG. 1 is a cross-sectional view of a liquid crystal display
device according to the related art. In FIG. 1, the LCD device
includes first and second substrates 31 and 11, which are spaced
apart and face each other, a liquid crystal material layer 50 is
interposed between the first and second substrates 31 and 11, and a
thin film transistor "T" is formed on the inner surface of the
first substrate 31. A pixel electrode 32 of a transparent
conducting material is formed on the first substrate 31, and the
pixel electrode 32 is disposed at a pixel region "P." The pixel
electrode 32 is connected to the thin film transistor "T," which
functions as a switching device for transmitting signals to the
pixel electrode 32. A first alignment layer 34 covers the thin film
transistor "T" and the pixel electrode 32. Although not shown, the
thin film transistor "T" includes a gate electrode connected to a
scanning line, an active layer formed on the gate electrode, and
source and drain electrodes separated apart from each other on the
active layer, wherein a portion of the active layer exposed between
the source and drain electrodes forms a channel of the thin film
transistor.
[0007] In FIG. 1, a black matrix 12 is formed on the inner surface
of the second substrate 11, and a color filter 14 is formed on the
black matrix 12. The color filter 14 includes the three sub-color
filters of red (R), green (G), and blue (B) disposed in the pixel
region "P" and overlaps the black matrix 12. A common electrode 18
made of a transparent conducting material is formed on the color
filter 14, and a second alignment layer 20 is formed on the common
electrode 18. The liquid crystal material layer 50 is disposed
between the first alignment layer 34 and the second alignment layer
20, wherein preliminary alignment of liquid crystal molecules of
the liquid crystal material layer 50 is dependent upon
characteristics of the alignment layers 34 and 20. Then, first and
second polarization films 36 and 22 are arranged outer surfaces of
the first and second substrates 31 and 11, respectively, wherein
transmission axes of the first and second polarization films 36 and
22 are perpendicular to each other.
[0008] FIGS. 2A to 2D are cross-sectional views of a fabrication
method for a color filter substrate of the liquid crystal display
device of FIG. 1 according to the related art. In FIG. 2A, the
black matrix 12 is formed on the second transparent substrate 11,
wherein the black matrix 12 has an opening corresponding to the
pixel region "P." The second transparent substrate 11 may be made
of glass, and the black matrix 12 may be made of an inorganic
material such as chromium (Cr), Cr/CrOx, or an organic material
that includes carbon. Here, the black matrix 12 material includes
an inorganic material such as chromium and is formed by a
sputtering method under vacuum conditions, whereby the
manufacturing process is complicated and expensive. Conversely,
forming the black matrix 12 of the organic material is advantageous
due to the relatively short manufacturing process, low cost, and
high visibility. Accordingly, the organic material is commonly
selected for the black matrix 12.
[0009] In FIG. 2B, the color filter layer 14 is formed within the
pixel region "P" on the second transparent substrate 11 having the
black matrix 12. The color filter layer 14 overlaps the black
matrix 12, and includes three sub-color filters 14a, 14b, and 14c
of red, green, and blue, respectively, and each of the sub-color
filters correspond to each of the pixel regions "P." The color
filter layer 14 may be formed by the pigment dispersion method,
which includes steps of coating a photosensitive color resin on a
substrate, exposing the color resin to a light, and developing the
color resin.
[0010] In FIG. 2C, the common electrode 18 and the alignment layer
20 are subsequently formed on the color filter layer 14. The common
electrode 18 is formed of a transparent conducting material, and
the alignment layer 20 is formed of polyimide. Thus, a color filter
substrate is completed.
[0011] In FIG. 2D, the polarization film 22 is formed on the outer
side of the color filter substrate. Although not shown, the
polarization film 22 is formed after forming a liquid crystal cell
by aligning and attaching the color filter substrate and an array
substrate. The array substrate is fabricated by processes of
deposition and patterning a thin film using several masks;
injecting liquid crystal materials; and sealing.
[0012] In the fabrication method of FIGS. 2A to 2D, as the color
filter substrate is fabricated using a photolithographic process,
the second transparent substrate 11 is chemically processed.
Accordingly, the second transparent substrate 11 must be formed of
specific materials that are chemically resistant. In addition, an
overcoat layer (not shown) may be formed on the color filter layer
14 to flatten an inner surface of the second transparent substrate
11. Accordingly, a total number of manufacturing processes is
increased, thereby increasing manufacturing costs.
SUMMARY OF THE INVENTION
[0013] Accordingly, the present invention is directed to a color
filter substrate for a liquid crystal display device and a
manufacturing method of the color filter substrate that
substantially obviates one or more of problems due to limitations
and disadvantages of the related art.
[0014] An object of the present invention is to provide a color
filter substrate and a method of manufacturing a color filter
substrate that reduces a total number of manufacturing processes
and reduces manufacturing costs.
[0015] Additional features and advantages of the invention will be
set forth in the description which follows, and in part will be
apparent from the description, or may be learned by practice of the
invention. The objectives and other advantages of the invention
will be realized and attained by the structure particularly pointed
out in the written description and claims hereof as well as the
appended drawings.
[0016] To achieve these and other advantages and in accordance with
the purpose of the present invention, as embodied and broadly
described, a color filter substrate for a liquid crystal display
device includes a polarizing substrate, a black matrix positioned
on the polarizing substrate, a color filter layer positioned on the
black matrix, and a common electrode positioned on the color filter
layer.
[0017] In another aspect, a method of fabricating a color filter
substrate for a liquid crystal display device includes steps of
forming a black matrix on a polarizing substrate, forming a color
filter layer on the black matrix, and forming a common electrode on
the color filter layer.
[0018] In another aspect, a method of fabricating a color filter
substrate for a liquid crystal display device includes steps of
aligning a first transcription film having a black resin layer, a
first light-to-heat conversion layer, and a first supporting film,
sequentially formed onto a polarizing substrate, selectively
performing a first thermal transfer process on a first portion of
the first transcription film, removing the first transcription film
except for the first portion where the first thermal transfer
process is performed, thereby forming a black matrix on the
polarizing substrate, aligning a second transcription film having a
color filter layer, a second light-to-heat conversion layer, and a
second supporting film, sequentially formed onto the polarizing
substrate including the black matrix, selectively performing a
second thermal transfer process on a first portion of the second
transcription film, removing the second transcription film except
for the first portion of the second transcription film where the
second thermal transfer process is performed, thereby forming a
color filter on the polarizing substrate including the black
matrix, and forming a common electrode on the color filter.
[0019] It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory and are intended to provide further explanation of
the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The accompanying drawings, which are included to provide a
further understanding of the invention and are incorporated in and
constitute a part of this specification, illustrate embodiments of
the invention and together with the description serve to explain
the principles of the invention. In the drawings:
[0021] FIG. 1 is a cross-sectional view of a liquid crystal display
device according to the related art;
[0022] FIGS. 2A to 2D are cross-sectional views of a fabrication
method for a color filter substrate of the liquid crystal display
device of FIG. 1 according to the related art;
[0023] FIG. 3 is a cross-sectional view of an exemplary color
filter substrate for a liquid crystal display device according to
the present invention;
[0024] FIG. 4 is a flow chart of an exemplary process for
fabricating a color filter substrate according to the present
invention; and
[0025] FIGS. 5A to 5D are cross-sectional views of an exemplary
method for fabricating a color filter substrate according to the
present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] Reference will now be made in detail to the preferred
embodiments of the present invention, which is illustrated in the
accompanying drawings.
[0027] FIG. 3 is a cross-sectional view of an exemplary color
filter substrate for a liquid crystal display device according to
the present invention. In FIG. 3, the exemplary color filter
substrate may include a polarizing substrate 100 having a pixel
region "P." The polarizing substrate 100 may function both as a
substrate to support elements and as a polarizer. A black matrix
102 may be formed on the polarizing substrate 100, and the black
matrix 102 may include an opening corresponding to the pixel region
"P." A color filter layer 104 may be formed on the black matrix 102
to overlap the black matrix 102. The color filter layer 104 may
include three sub-color filters 104a, 104b, and 104c of red (R),
green (G), and blue (B), respectively, wherein each of the
sub-color filters 104a, 104b, and 104c may correspond to each of
the pixel regions "P." The color filter layer 104 may include a
substantially flat surface. A common electrode 106 made of a
transparent conducting material may be formed on the color filter
layer 104, and an alignment layer 108 may be formed on the common
electrode 106.
[0028] In addition, the color filter layer 104 may be formed using
a thermal transfer method, which may be commonly referred to as a
thermal imaging method. During the thermal transfer method, a laser
beam may be irradiated onto a transcription film, thereby
transferring a pattern onto a substrate. Accordingly, in the
thermal transfer method, since manufacturing steps of coating and
developing are not necessary, a total number of manufacturing
processes is decreased as compared to a pigment dispersed
method.
[0029] FIG. 4 is a flow chart of an exemplary process for
fabricating a color filter substrate according to the present
invention. In FIG. 4, a first step ST1 may include preparation of a
substrate and a transcription film. According to the present
invention, the substrate of step ST1 may include the polarizing
substrate of FIG. 3. The transcription film may include a color
filter layer, a light-to-heat conversion (LTHC) layer, and a
supporting film. The LTHC layer may be made of a material that
emits heat by application of energy from a laser beam, for example,
and may be disposed between the color filter layer and the
supporting film.
[0030] In a second step ST2, the transcription film may be aligned
on the substrate. Accordingly, the color filter layer of the
transcription film may contact the substrate. In addition, an
adhesive layer may be formed between the color filter layer and the
substrate. The adhesive layer may be formed on the substrate or on
the color filter layer of the transcription film.
[0031] In a third step ST3, a laser beam may be irradiated onto the
aligned transcription film on the substrate. Then, the color filter
layer may be exposed to a laser beam and transferred to the
substrate by the LTHC layer.
[0032] In step ST4, the LTHC layer and the supporting film may be
removed from the transcription film, whereby a color filter layer
may remain on the substrate. In addition, by repeating the first
ST1, second ST2, third ST3, and fourth ST4 steps, a color filter
layer including sub-color filters red, green, and blue may be
formed on the substrate.
[0033] FIGS. 5A to 5D are cross-sectional views of an exemplary
method for fabricating a color filter substrate according to the
present invention. In FIG. 5A, a black matrix 102 may be formed on
a polarizing substrate 100. The black matrix 102 may be formed by a
thermal transfer method as described above in FIG. 4, in which a
transcription film including a black resin layer may be used. The
black matrix 102 may include an opening corresponding to a pixel
region "P." A first thermal transfer method of forming the black
matrix 102 may use a transcription film, which has a black resin
layer in place of the color filter layer of FIG. 4 and the black
resin layer may include carbon. Accordingly, the polarizing
substrate 100 may function as both a substrate and a polarizer, and
may include a plastic material such as polyvinyl alcohol (PVA).
[0034] In FIG. 5B, a color filter layer 104 may be formed on the
black matrix 102 by the same process shown in FIG. 4. The color
filter layer 104 may include three sub-color filters 104a, 104b,
and 104c of red, green, and blue, respectively. Accordingly, since
the black matrix 102 and the color filter layer 104 are formed by
the thermal transfer method, the substrate does not necessarily
have to be chemical resistant. Thus, a substrate made of a plastic
material, which is cheaper than glass material, may be used. In
addition, since the color filter layer 104 may have a substantially
flat surface, an overcoat layer may not necessarily be required in
order to planarize the surface of the polarizing substrate 100,
including the color filter layer 104 and the black matrix 102.
Therefore, a total number of manufacturing processes and
manufacturing expenses may be reduced.
[0035] In FIG. 5C, a common electrode 106 may be formed by
depositing a transparent conductive material on the color filter
layer 104. Then, the transparent conductive material may be
patterned. The transparent conductive material may include
Indium-Tin-Oxide (ITO) or Indium-Zinc-Oxide (IZO), for example.
Alternatively, the transparent conductive material may be
selectively formed such that subsequent patterning is
unnecessary.
[0036] In FIG. 5D, an alignment layer 108 may be formed on the
common electrode 106, and may include a high molecular material
such as polyimide. The alignment layer 108 may function to control
alignment of liquid crystal molecules of a liquid crystal material
layer that may be subsequently formed on the alignment layer 108.
The alignment of the liquid crystal molecules may be controlled by
a rubbing method or a photo-aligning method.
[0037] It will be apparent to those skilled in the art that various
modifications and variations can be made in the color filter
substrate and method of fabricating a color filter substrate of the
present invention without departing from the spirit or scope of the
invention. Thus, it is intended that the present invention cover
the modifications and variations of this invention provided they
come within the scope of the appended claims and their
equivalents.
* * * * *