JP2005084087A - Liquid crystal display and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display which is inexpensive and has satisfactory display quality, and to provide its manufacturing method, wherein increase of the number of manufacturing steps is suppressed. <P>SOLUTION: In an array substrate of the liquid crystal display, a colored resin layer 24 which constitutes a color filter layer has a peripheral part 24E along the periphery of each pixel and an effective part 24X formed on the inner side enclosed by the peripheral part 24E and having film thickness thinner than that of the peripheral part 24E. A pixel electrode 151 is disposed on the effective part 24X of the colored resin layer 24. After the color filter layer is formed by disposing the colored layer having the peripheral part and the effective part, a conductive film having an optical transmission property is film-deposited on the entire surface of the color filter layer, the surface of the conductive film is polished to expose the peripheral part 24E of the colored resin layer 24 and the pixel electrode 151 independent for every pixel is formed on the effective part 24X of the colored resin layer 24. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display device and a manufacturing method thereof, and more particularly to an active matrix color liquid crystal display device having a pixel electrode on a color filter layer and a manufacturing method thereof.

  Since the liquid crystal display device has features such as light weight, thinness, and low power consumption, it is applied to various fields such as OA equipment, information terminals, watches, and televisions. In particular, a liquid crystal display device having a thin film transistor, that is, a TFT, is applied as a monitor that displays data including a large amount of information, such as a portable television or a computer, because of its high responsiveness.

  A generally used liquid crystal display device is configured by sandwiching a liquid crystal layer between two glass substrates having electrodes. These two substrates are fixed around the periphery with an adhesive applied except for the liquid crystal sealing port. In addition, the liquid crystal display device for color display is arranged from a colored resin layer arranged for each pixel of one of the two glass substrates and colored red (R), green (G), and blue (B). The color filter layer is provided.

  Recently, in liquid crystal display devices, demands such as an increase in screen size and an improvement in display quality are increasing. In such a demand for further performance improvement, one of the factors hindering this is a problem of flatness of the surface of the color filter layer. That is, the colored resin layers of the respective colors forming the color filter layer are arranged so as to overlap each other at the peripheral edge portion, thereby suppressing light leakage between the colored resin layers.

  However, the peripheral edge portion of the colored resin layer is thicker than the inner effective portion surrounded by the peripheral edge portion. As described above, the color filter layer has a slight step on the surface (the surface on the side where the gap for sandwiching the liquid crystal layer is formed), and the gap for sandwiching the liquid crystal layer changes. At the same time, the alignment of the liquid crystal molecules is disturbed in the vicinity of the step, which is a factor of degrading display performance such as contrast. However, it is difficult to form the surface of the color filter layer completely flat.

Therefore, a method has been proposed in which a transparent overcoat layer is disposed on the color filter layer and then the surface on the side where the gap is formed is flattened by mechanical polishing of the overcoat layer (see, for example, Patent Document 1). .)
JP 7-294720 A

  However, the method of disposing an overcoat layer as described in Patent Document 1 has a problem that the number of manufacturing steps is increased and the manufacturing cost is increased. Moreover, when forming a transparent conductive film layer on such an overcoat layer, a photolithography process etc. are needed in order to pattern a transparent conductive film layer, and the number of manufacturing processes increases.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an inexpensive liquid crystal display device having a good display quality and a method for manufacturing the same, suppressing an increase in the number of manufacturing steps.

A method of manufacturing a liquid crystal display device according to the first aspect of the present invention includes:
A method of manufacturing a liquid crystal display device configured by sandwiching a liquid crystal layer between a first substrate and a second substrate,
In the first substrate,
A color filter layer is formed by disposing a colored resin layer having an effective portion having a film thickness thinner than the peripheral edge on the inner periphery surrounded by the peripheral edge along the peripheral edge of each pixel, and
Forming a light-transmitting conductive film on the entire surface of the color filter layer;
Polishing the conductive film disposed on the peripheral edge of the colored resin layer to expose the peripheral edge of the colored resin layer;
An independent pixel electrode is formed for each pixel on the effective portion of the colored resin layer.

A liquid crystal display device according to a second aspect of the present invention provides:
A liquid crystal layer is sandwiched between the first substrate and the second substrate,
The first substrate is
Switching elements arranged for each pixel;
A color filter layer composed of a plurality of colored resin layers each colored in a plurality of colors, and arranged by arranging the colored resin layers of each color in corresponding color pixels;
A pixel electrode disposed on the color filter layer for each pixel and electrically connected to the switching element through a contact hole formed in the color filter layer;
The colored resin has a peripheral portion along the periphery of each pixel, and an effective portion having a film thickness thinner than the peripheral portion on the inner side surrounded by the peripheral portion,
The pixel electrode is disposed on an effective portion of the colored resin layer, and a peripheral surface of the colored resin layer is substantially flat over the entire surface.

  According to the present invention, an increase in the number of manufacturing steps can be suppressed, and an inexpensive liquid crystal display device with good display quality and a manufacturing method thereof can be provided.

  A liquid crystal display device and a manufacturing method thereof according to an embodiment of the present invention will be described below with reference to the drawings.

  As shown in FIGS. 1 and 2, a liquid crystal display device according to this embodiment, for example, an active matrix liquid crystal display device 1, includes a transmissive liquid crystal panel 10 and a drive circuit that supplies a drive signal to the liquid crystal panel 10. A substrate 500 and a backlight unit 800 that illuminates the liquid crystal panel 10 from the back side are provided. The liquid crystal panel 100 and the drive circuit board 500 are electrically connected via a flexible wiring board 950. The flexible wiring board 950 is electrically connected to the liquid crystal panel 100 and the drive circuit board 500 by an anisotropic conductive film (ACF) or the like.

  The liquid crystal panel 10 includes an array substrate (first substrate) 100, a counter substrate (second substrate) 200 disposed to face the array substrate 100, and a liquid crystal layer 300 held between the array substrate 100 and the counter substrate 200. And have. The array substrate 100 and the counter substrate 200 are bonded together by a seal member 106 while forming a predetermined gap for sandwiching the liquid crystal layer 300. The liquid crystal layer 300 is composed of a liquid crystal composition sealed between the array substrate 100 and the counter substrate 200.

  In such a liquid crystal display panel 10, a display area 102 for displaying an image is composed of a plurality of pixels PX (R, G, B) arranged in an m × n matrix. The display area 102 is defined on the inner side surrounded by the sealing material 106.

  In the display region 102, the array substrate 100 is formed on a light-transmissive insulating substrate 11 such as a glass substrate, a plurality of scanning lines Y, a plurality of signal lines X, a plurality of switching elements 121, and a color filter layer 24 (R G, B), a plurality of pixel electrodes 151, a plurality of columnar spacers 31, an alignment film 13A, and the like. In the peripheral area 104 defined around the display area 102, the array substrate 100 includes a light shielding layer SP and the like.

  That is, the m scanning lines Y are arranged along the row direction of the pixel electrodes 151. The n signal lines X are arranged so as to be orthogonal to the m scanning lines Y, and are arranged along the column direction of the pixel electrodes 151. The m × n switching elements 121 are arranged for each pixel in the vicinity of the intersection between the scanning line Y and the signal line X, and are configured by n-channel thin film transistors having a polysilicon semiconductor layer, that is, pixel TFTs.

  The color filter layer 24 (R, G, B) is composed of a plurality of colored resin layers colored in a plurality of colors, that is, red (R), green (G), and blue (B), respectively, The light of each color component of green and blue is transmitted. The colored resin layers of the respective colors are arranged so as to cover the switching elements 121 arranged in the corresponding color pixels. That is, the red resin layer 24R, the green resin layer 24G, and the blue resin layer 24B are disposed in the red pixel PXR, the green pixel PXG, and the blue pixel PXB, respectively.

  As shown in FIG. 4, each pixel PX is defined by a light-shielding wiring portion (for example, a signal line X, a scanning line Y, an auxiliary capacitance element, etc.) W, and inside the backlight unit is surrounded by the wiring portion W. An aperture AP that can transmit illumination light from 800 is provided. In addition, each colored resin layer 24 has a peripheral portion 24E along the periphery of each pixel PX, and an effective portion 24X on the inner side surrounded by the peripheral portion 24E.

  The effective portion 24X is mainly located on the opening AP. The peripheral edge 24E is mainly located on the wiring part W. The peripheral edge 24E is mechanically polished by a polishing process described later, and is almost flattened. The film thickness T1 of the peripheral part 24E is thicker than the film thickness T2 of the effective part 24X.

  The difference between the film thickness T1 and the film thickness T2 corresponds not only to the thickness of the wiring part W but also to the film thickness obtained by superimposing the peripheral parts of other colored resin layers arranged in adjacent pixels. Alternatively, the difference between the film thickness T1 and the film thickness T2 is not only the thickness of the wiring portion W, but the peripheral portion 24E is intentionally formed thicker than the effective portion 24X in the same colored resin layer arranged in the same pixel. This corresponds to the difference in film thickness.

  The columnar spacer 31 is disposed on the color filter layer 24 (R, G, B) so as to be positioned on the light-shielding wiring portion, and sandwiches the liquid crystal layer 300 between the array substrate 100 and the counter substrate 200. Forming a gap. The light shielding layer SP is arranged in a frame shape along the periphery of the effective display area 102. The light blocking layer SP is formed of a colored resin, for example, a black resin material, in order to block light transmission. The columnar spacers 31 may be formed in the same process using the same resin material as the light shielding layer SP. Thereby, the number of manufacturing steps can be reduced as compared with the case where the columnar spacer 31 and the light shielding layer SP are separately formed.

  The alignment film 13A is disposed so as to cover the entire plurality of pixel electrodes 151. The alignment film 13A aligns liquid crystal molecules contained in the liquid crystal layer 300 in a predetermined direction with respect to the array substrate 100.

  The m × n pixel electrodes 151 are arranged for each pixel PX on the color filter layer 24 (R, G, B). Such a pixel electrode 151 is formed of a light-transmitting conductive member such as ITO (indium tin oxide). Each pixel electrode 151 is electrically connected to the corresponding pixel TFT 121 via a contact hole 26 that penetrates the color filter layer 24 (R, G, B).

  That is, the pixel electrode 151 is disposed on the effective portion 24X of the colored resin layer 24 as shown in FIG. The colored resin layer 24 is mechanically polished in the polishing step, and the surface of the peripheral edge 24E of the colored resin layer 24 is substantially flattened over the entire surface.

  Each pixel TFT 121 has a semiconductor layer 112 formed of a polysilicon film, as shown in FIG. 3 in more detail. The semiconductor layer 112 is disposed on the undercoating layer 60 disposed on the glass substrate 11, and has a drain region 112D and a source region 112S formed by doping impurities on both sides of the channel region 112C. Yes.

  The gate electrode 63 of the pixel TFT 121 is formed integrally with the scanning line Y, for example, and is disposed to face the channel region 112 </ b> C of the semiconductor layer 112 with the gate insulating film 62 interposed therebetween. The drain electrode 88 of the pixel TFT 121 is formed integrally with the signal line X, for example, and is electrically connected to the drain region 112D of the semiconductor layer 112 through a contact hole 77 that penetrates the gate insulating film 62 and the interlayer insulating film 76. It is formed by. The source electrode 89 of the pixel TFT 121 is formed by being electrically connected to the source region 112 </ b> S of the semiconductor layer 112 through a contact hole 78 that penetrates the gate insulating film 62 and the interlayer insulating film 76.

  The source electrode 89 is electrically connected to the pixel electrode 151 via the contact hole 26 formed in the color filter layer 24 (R, G, B) covering the interlayer insulating film 76, the drain electrode 88, and the source electrode 89. It is connected. Thereby, the pixel TFT 121 is connected to the scanning line Y and the signal line X, is turned on by the drive signal from the scanning line Y, and applies the signal voltage from the signal line X to the pixel electrode 151.

  The pixel electrode 151 is electrically connected to an auxiliary capacitor element that forms an auxiliary capacitor C electrically parallel to the liquid crystal capacitor CL. That is, the auxiliary capacitance electrode 61 is formed of a polysilicon film in the same layer as the semiconductor layer 121 and is configured to have the same potential as the pixel electrode 151. At least a part of the auxiliary capacitance line 52 is disposed opposite to the auxiliary capacitance electrode 61 via the gate insulating film 62 and is set to a predetermined potential.

  Wiring portions such as the signal lines X, the scanning lines Y, and the auxiliary capacitance lines 52 are formed of a light-shielding low resistance material such as aluminum or molybdenum-tungsten. In this embodiment, the scanning lines Y and the auxiliary capacitance lines 52 arranged substantially parallel to each other are formed of molybdenum-tungsten. Further, the signal line X, the drain electrode 88, and the source electrode 89 are mainly formed of aluminum.

  On the other hand, in the display region 102, the counter substrate 200 includes a counter electrode 204 formed on a light-transmitting insulating substrate 21 such as a glass substrate, an alignment film 13B covering the counter electrode 204, and the like. The counter electrode 204 is formed of a light transmissive conductive member such as ITO. The counter electrode 204 is disposed in common for all the pixels PX (R, G, B) and faces all the m × n pixel electrodes 151 through the liquid crystal layer 300. The alignment film 13 </ b> B aligns liquid crystal molecules included in the liquid crystal layer 300 in a predetermined direction with respect to the counter substrate 200.

  In the peripheral region 104, the array substrate 100 has a scanning line driving circuit 18 including a driving TFT for driving the scanning line Y, a signal line driving circuit 19 including a driving TFT for driving the signal line X, and the like. The driving TFTs included in the scanning line driving circuit 18 and the signal line driving circuit 19 are composed of an n-channel thin film transistor and a p-channel thin film transistor having a polysilicon semiconductor layer.

  A polarizing plate PL1 and a polarizing plate PL2 are provided on the outer surfaces of the array substrate 100 and the counter substrate 200 in the liquid crystal display panel 10, respectively. The deflecting plates PL1 and PL2 are arranged, for example, so that their polarization axes are orthogonal to each other.

  By the way, in the color liquid crystal display panel, various layouts for arranging the red resin layer 24R, the green resin layer 24G, and the blue resin layer 24B constituting the color filter layer have been proposed. For example, the layout of the color filter layer 24 (R, G, B) includes a mosaic arrangement, a delta arrangement, a stripe arrangement, a quad (square) arrangement, etc., as shown in FIGS. .

  In the mosaic arrangement, the delta arrangement, and the quad arrangement, the colored resin layers of other different colors are arranged adjacent to each other in the row direction and the column direction of the colored resin layer of a certain color. In the case of such an arrangement, the entire peripheral edge portion of a colored resin layer of a certain color overlaps with another colored resin layer of a different color and has a thickness that is thicker than the effective portion.

  For example, taking the delta arrangement as an example, as shown in FIG. 6, the red resin layer 24R and the blue resin layer 24B are arranged adjacent to the row direction H and the column direction V of the green resin layer 24G. Then, the entire peripheral edge 24E along the row direction H and the column direction V of the green resin layer 24G overlaps with the peripheral edge 24E of the red resin layer 24R and the blue resin layer 24B on the wiring part W, and from the effective part 24X. The film thickness is also thick. That is, the difference between the film thickness of the peripheral part 24E and the film thickness T2 of the effective part 24X is not only the thickness of the wiring part W but also the peripheral part 24E of other colored resin layers arranged in adjacent pixels. This corresponds to the combined film thickness.

  In the stripe arrangement, the colored resin layers of other colors are arranged adjacent to each other only in the row direction or the column direction of the colored resin layer of a certain color. In the case of such an arrangement, the peripheral portion along the row direction or the column direction of a colored resin layer of a certain color overlaps with another colored resin layer of a different color, and has a thickness greater than that of the effective portion.

  For example, as shown in FIG. 7, in the case of a stripe arrangement extending in the column direction V, the red resin layer 24R and the blue resin layer 24B are disposed adjacent to only the row direction H of the green resin layer 25G. Become. Then, the peripheral edge 24E along the column direction V of the green resin layer 24G overlaps the peripheral edge 24E of the red resin layer 24R and the blue resin layer 24B on the wiring part W, and has a film thickness larger than the effective part 24X. Become. Further, the peripheral edge portion 24E along the row direction H of the green resin layer 24G is formed on the wiring portion W so as to be thicker than the effective portion 24X.

  That is, the difference between the film thickness of the peripheral edge 24E along the column direction and the film thickness T2 of the effective part 24X is not only the thickness of the wiring part W but also of other colored resin layers arranged in adjacent pixels. This corresponds to the thickness of the overlapped peripheral edge 24E. Further, the difference between the film thickness of the peripheral portion 24E along the row direction and the film thickness T2 of the effective portion 24X corresponds not only to the thickness of the wiring portion W but also to the difference in film thickness formed thicker than the effective portion 24X. To do.

  Next, a first manufacturing method of the liquid crystal display panel 10 having the above-described structure will be described. Here, a case where the color filter layer 24 (R, G, B) made of a colored resin layer having a delta arrangement is formed will be described as an example.

  In the manufacturing process of the array substrate 100, first, after forming the undercoating layer 60 on the glass substrate 11, the polysilicon semiconductor layer 112 such as the pixel TFT 121 and the auxiliary capacitance electrode 61 are formed. Subsequently, after forming the gate insulating film 62, various wiring portions such as the scanning line Y, the auxiliary capacitance line 52, and the gate electrode 63 integrated with the scanning line Y are formed.

  Subsequently, using the gate electrode 63 as a mask, an impurity is implanted into the polysilicon semiconductor layer 112 to form a drain region 112D and a source region 112S on both sides of the channel region 112C, and then the entire substrate is annealed to activate the impurity. To do. Subsequently, after forming the interlayer insulating film 76, the signal line X is formed, and the drain electrode 88, the source electrode 89, and the contact electrode 80 of the pixel TFT 121 are formed integrally with the signal line X.

Subsequently, a color filter layer 24 (R, G, B) of a color corresponding to each color pixel is formed. That is, a photosensitive colored resin material, for example, an ultraviolet curable acrylic resin material CR-2000 (manufactured by Fuji Film Ohlin Co., Ltd.) in which a red pigment is dispersed is applied to the entire surface of the substrate by a spinner. Then, this resin material is exposed at an exposure amount of 100 mJ / cm ² at a wavelength of 365 nm through a photomask that irradiates light to a portion corresponding to the red pixel. The resin material is developed with a 1% aqueous solution of KOH for 20 seconds, further washed with water, and then baked. Thereby, as shown in FIG. 8A, the red resin layer 24R is arranged in the red pixel.

  Subsequently, by repeating the same process, as shown in FIG. 8B, a green color composed of an ultraviolet curable acrylic resin material CG-2000 (manufactured by Fuji Film Olin Co., Ltd.) in which a green pigment is dispersed. A resin layer 24G is formed. At this time, the green resin layer 24G is disposed in the green pixel and is disposed so as to overlap a part of the peripheral edge portion of the previously formed red resin layer 24R.

Subsequently, by repeating the same process, as shown in FIG. 8B, a blue color made of an ultraviolet curable acrylic resin material CB-2000 (produced by Fuji Film Olin Co., Ltd.) in which a blue pigment is dispersed. The resin layer 24B is formed. At this time, the blue resin layer 24B is disposed on the blue pixel, and is disposed so as to overlap a part of the peripheral edge of the green resin layer 24G previously formed and the exposed peripheral edge of the red resin layer 24R. .
Further, in the process of forming these colored resin layers 24 (R, G, B), contact holes 26 that can contact the pixel TFTs 121 are also formed at the same time.

  In the color filter layer thus formed, the peripheral portions of the red resin layer 24R, the green resin layer 24G, and the blue resin layer 24B overlap each other, and in this embodiment, for example, overlap each other with a width of 2 μm. Moreover, the average value of the film thickness in the effective part of each colored resin layer is about 3 μm, and the film thickness of the peripheral part where the plurality of colored resin layers overlap is about 3.7 μm. The difference in film thickness between the effective portion and the peripheral portion can be easily changed by adjusting the overlap width.

  Subsequently, as shown in FIG. 9A, a light-transmitting conductive film, for example, ITO with a film thickness of 1500 angstroms is formed on the entire surface of the color filter layer 24 (R, G, B) by sputtering or the like. Form a film. At this time, each contact hole 26 is also filled with the conductive film.

  Subsequently, as shown in FIG. 9B, the surface of the conductive film is polished to expose the peripheral portions of the respective colored resin layers. That is, the surface of the ITO film is mechanically polished to remove the thick peripheral portion 24E where the plurality of colored resin layers 24 (R, G, B) overlap and the ITO film on the peripheral portion 24E.

  As a result, the ITO film remains only on the effective portion 24X of each colored resin layer, and the ITO film on the entire peripheral edge 24E surrounding the effective portion 24X is removed, so that an independent pixel electrode 151 is formed for each pixel. In this embodiment, the surface is removed with a polishing amount of about 0.5 μm, the surface of the pixel electrode 151 remaining on the effective portion 24X of the colored resin layer, and the surface of the exposed peripheral portion 24E of the colored resin layer Is almost flat.

  That is, by such mechanical polishing, the surface of the array substrate on the side in contact with the liquid crystal layer can be flattened, and at the same time, the pixel electrode 151 can be patterned for each pixel. Note that the interval between adjacent pixel electrodes 151 can be arbitrarily adjusted by the film thickness of the peripheral portion 24E and the effective portion 24X and the polishing amount depending on the overlapping amount of the colored resin layers.

  The mechanical polishing as described above is performed using, for example, a buff polishing apparatus. That is, a substrate is fixed on a horizontal mounting table, a rotating plate having a polishing surface that is rotationally driven in a plane parallel to the mounting table is rotated at a predetermined rotation speed, and the polishing surface is applied to the ITO film on the substrate surface at a predetermined pressure. Make contact. Thereby, the peripheral part of an ITO film | membrane and a colored resin layer is grind | polished with the abrasive | polishing agent supplied on the grinding | polishing surface.

Subsequently, for example, a black ultraviolet curable acrylic resin resist NN700 (manufactured by JSR Corporation) is applied to the entire surface of the substrate by a spinner. Thereafter, the resist film is dried at 90 ° C. for 10 minutes, and then exposed using a photomask having a predetermined pattern shape at a wavelength of 365 nm and an exposure amount of 300 mJ / cm ² . The resist film is developed with an alkaline aqueous solution having a pH of 11.5 and baked at 200 ° C. for 60 minutes. Thereby, the columnar spacer 31 is formed on the color filter layer 24 (R, G, B), and the light shielding layer SP is formed along the periphery of the display region 102.

Subsequently, SE-7511L (manufactured by Nissan Chemical Industries, Ltd.) as an alignment film material is applied over the entire surface of the substrate with a film thickness of 500 angstroms and baked to form an alignment film 13A.
Thereby, the array substrate 100 is manufactured.

On the other hand, in the manufacturing process of the counter substrate 200, first, an ITO film is formed on the glass substrate 21 with a film thickness of 1500 Å by sputtering or the like, and the counter electrode 204 is formed by patterning. After that, SE-7511L (manufactured by Nissan Chemical Industries, Ltd.) as an alignment film material is applied to the entire substrate in a film thickness of 500 angstroms and baked to form the alignment film 13B.
Thereby, the counter substrate 200 is manufactured.

  In the manufacturing process of the liquid crystal display panel 10, the seal member 106 is printed and applied along the outer edge of the counter substrate 200 leaving the liquid crystal inlet, and further, an electrode transfer material for applying a voltage from the array substrate 100 to the counter electrode 200. Is formed on the electrode transition electrode around the seal member 106. Subsequently, the array substrate 100 and the counter substrate 200 are arranged so that the alignment film 13A of the array substrate 100 and the alignment film 13B of the counter substrate 200 face each other, and the sealing member 106 is cured by heating to cure the two substrates. to paste together. Subsequently, a liquid crystal composition such as ZLI-1565 (made by MERCK) having positive dielectric anisotropy is injected from a liquid crystal injection port, and the liquid crystal injection port is sealed with an ultraviolet curable resin or the like. 300 is formed. Further, the deflection plate PL1 is provided on the outer surface of the array substrate 100, and the deflection plate PL2 is provided on the outer surface of the counter substrate 200.

  An active matrix type color liquid crystal display panel is manufactured by the manufacturing method as described above.

  According to the liquid crystal display device manufactured by the first manufacturing method described above, the alignment film in contact with the liquid crystal layer can be flattened due to the overlapping of the colored resin layers constituting the color filter layer at the peripheral edge portions. The surface can be formed flat. Thereby, the gap for sandwiching the liquid crystal layer is made uniform, and the disorder of the arrangement of the liquid crystal molecules can be suppressed, and the display performance can be improved.

  In addition, it is not necessary to provide an overcoat layer on the color filter layer. In addition, the entire peripheral edge portion of each colored resin layer constituting the color filter layer is made thicker than the effective portion, and the surface of the conductive film formed on the entire surface of the color filter layer is polished, so that the pixel electrode is changed for each pixel. To pattern. That is, planarization of the color filter layer and patterning of the pixel electrode can be performed at the same time, and a photolithography process for patterning the conductive film on the color filter layer becomes unnecessary.

  For this reason, the number of manufacturing steps can be reduced, and an increase in manufacturing cost can be suppressed. Therefore, an inexpensive liquid crystal display device with excellent display quality can be provided.

  This polishing step is performed after a conductive film is formed on the entire surface of the color filter layer. That is, the colored resin layer and the conductive film are polished after filling the contact holes formed in the colored resin layers with the conductive film. For this reason, the contact hole is not filled with the colored resin material removed in the polishing process, and the occurrence of poor connection between the pixel TFT 121 and the pixel electrode 151 can be prevented.

  In the above-described manufacturing method, the pixel electrode can be patterned in the polishing process. However, in order to separate each pixel electrode more reliably, a normal photolithography process is added to form a chemically conductive film. May be removed. In this case, since it is an auxiliary process, patterning can be performed in a shorter time than in the prior art.

  Next, a second manufacturing method of the liquid crystal display panel 10 having the above structure will be described. Here, a case where the color filter layer 24 (R, G, B) made of a colored resin layer in a stripe arrangement is formed will be described as an example. The second manufacturing method is different only in the manufacturing process of the color filter layer 24 (R, G, B), and the other steps are substantially the same as those of the first manufacturing method, and thus the description thereof is omitted. .

  That is, as shown in FIG. 10A, the color filter layer 24 (R, G, B) of the color corresponding to each color pixel is formed as in the first manufacturing method. First, a photosensitive colored resin material, for example, an ultraviolet curable acrylic resin material CR-2000 (manufactured by Fuji Film Ohlin Co., Ltd.) in which a red pigment is dispersed is applied to the entire surface of the substrate by a spinner.

Then, the resin material is exposed at a first exposure amount corresponding to a first region that forms a peripheral portion along the row direction of the red pixel, and a second portion that forms another part of the red pixel. The exposure is performed with a second exposure amount different from the first exposure amount corresponding to the region. In this resin material exposure step, for example, the resin materials are collectively exposed at a wavelength of 365 nm using photomasks having different transmittances in patterns corresponding to the first region and the second region, respectively. When the photosensitive colored resin material is a negative type, the first exposure amount for forming the peripheral portion of the thick film is set larger than the second exposure amount.
The resin material is developed with a 1% aqueous solution of KOH for 20 seconds, further washed with water, and then baked.

  As a result, as shown in FIG. 10A, the red resin layer 24R is arranged in a stripe pattern across a plurality of red pixels arranged along the column direction V. In addition, the peripheral edge portion 24E along the row direction H of the red resin layer 24R is formed to a thickness greater than that of the effective portion 24X.

  Subsequently, by repeating the same process, as shown in FIG. 10 (b), a green color composed of an ultraviolet curable acrylic resin material CG-2000 (manufactured by Fuji Film Olin Co., Ltd.) in which a green pigment is dispersed. A resin layer 24G is formed. At this time, the green resin layer 24G is arranged in a stripe shape over a plurality of green pixels arranged along the column direction V, and one peripheral portion along the column direction V of the green resin layer 24G is formed first. The red resin layer 24R is disposed so as to overlap one peripheral portion along the column direction V. In addition, the peripheral edge 24E along the row direction H of the green resin layer 24G is formed to a thickness greater than that of the effective portion 24X.

  Subsequently, by repeating the same process, as shown in FIG. 10 (c), a blue color made of an ultraviolet curable acrylic resin material CB-2000 (Fuji Film Orin Co., Ltd.) in which a blue pigment is dispersed. The resin layer 24B is formed. At this time, the blue resin layer 24B is arranged in a stripe shape over a plurality of blue pixels arranged along the column direction V, and the peripheral portion along the column direction V of the blue resin layer 24B is formed in the green color previously formed. It arrange | positions so that it may overlap with the other peripheral part along the column direction V of the resin layer 24G, and the other peripheral part along the column direction V of the red resin layer 24R. In addition, the peripheral edge 24E along the row direction H of the blue resin layer 24B is formed to a thickness greater than that of the effective portion 24X.

  In the color filter layer thus formed, only the peripheral portions along the column direction V of the red resin layer 24R, the green resin layer 24G, and the blue resin layer 24B overlap each other. In this embodiment, the width is, for example, 2 μm. Are overlapping. Moreover, the average value of the film thickness in the effective part of each colored resin layer is about 3 μm, and the film thickness of the peripheral part where the plurality of colored resin layers overlap is about 3.7 μm.

Subsequently, as described with reference to FIGS. 9A and 9B, a light-transmitting conductive film is formed on the entire surface of the color filter layer 24 (R, G, B) by sputtering or the like. The film is formed with a film thickness of 1500 Å. At this time, each contact hole 26 is also filled with the conductive film. And the surface of an electrically conductive film is grind | polished and the peripheral part of each colored resin layer is exposed. That is, the surface of the ITO film is mechanically polished, and the peripheral portion 24E along the column direction in which the plurality of colored resin layers 24 (R, G, B) are overlapped, along the row direction in which the monochromatic colored resin layer is formed in a thick film. The peripheral edge 24E and the ITO film on the peripheral edge 24E are removed.
Further, in the process of forming these colored resin layers, a contact hole 26 that can contact the pixel TFT 121 is also formed at the same time.

  As a result, the ITO film remains only on the effective portion 24X of each colored resin layer, and the ITO film on the entire peripheral edge 24E surrounding the effective portion 24X is removed, so that an independent pixel electrode 151 is formed for each pixel.

  According to the liquid crystal display device manufactured by the second manufacturing method described above, an effect similar to that of the first manufacturing method can be obtained, and an inexpensive liquid crystal display device having excellent display quality can be provided. In the second manufacturing method, in the step of forming each colored resin layer, the photosensitive colored resin material is collectively exposed using photomasks having different transmittances. However, the thickness is measured using two types of photomasks. You may expose separately the peripheral part and other part of a film | membrane.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the spirit of the invention in the stage of implementation. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

FIG. 1 schematically shows a configuration of a liquid crystal display device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing the structure of a liquid crystal display panel applicable to the liquid crystal display device shown in FIG. FIG. 3 is a cross-sectional view schematically showing the structure of the array substrate in the liquid crystal display panel shown in FIG. FIG. 4 is a schematic plan view for explaining the structure of the colored resin layer constituting the color filter layer. 5A to 5D are diagrams for explaining a layout example of a color pixel array. FIG. 6 is a diagram for explaining an overlapping state of colored resin layers having a delta arrangement. FIG. 7 is a view for explaining an overlapping state of colored resin layers in a stripe arrangement. FIGS. 8A to 8C are diagrams for explaining a process for forming a color filter layer having a delta arrangement. FIGS. 9A and 9B are diagrams for explaining the polishing process. FIGS. 10A to 10C are views for explaining a process for forming a color filter layer having a stripe arrangement.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display device, 10 ... Liquid crystal display panel, 24 (R, G, B) ... Color filter layer, 26 ... Contact hole, 31 ... Columnar spacer, 100 ... Array substrate, 121 ... Pixel TFT (switching element), 151 ... Pixel electrode, 200 ... Counter substrate, 204 ... Counter electrode, 300 ... Liquid crystal layer, PX (R, G, B) ... (Red, green, blue) pixel, X ... Signal line, Y ... Scanning line

Claims (8)

In a method for manufacturing a liquid crystal display device configured by sandwiching a liquid crystal layer between a first substrate and a second substrate,
In the first substrate,
A color filter layer is formed by disposing a colored resin layer having an effective portion with a film thickness thinner than the peripheral edge on the inner periphery surrounded by the peripheral edge along the peripheral edge of each pixel, and
Forming a light-transmitting conductive film on the entire surface of the color filter layer;
Polishing the conductive film disposed on the peripheral edge of the colored resin layer to expose the peripheral edge of the colored resin layer;
An independent pixel electrode is formed for each pixel on the effective portion of the colored resin layer. The color filter layer includes a first colored resin layer colored in a first color, a second colored resin layer colored in a second color, and a third colored resin layer colored in a third color,
2. The method of manufacturing a liquid crystal display device according to claim 1, wherein the second colored resin layer and the third colored resin layer are arranged adjacent to each other in a row direction and a column direction of the first colored resin layer. In the step of forming the color filter layer,
Disposing the first colored resin layer in a corresponding first color pixel;
The second colored resin layer is disposed on the corresponding second color pixel, and is disposed so as to overlap a part of the peripheral edge of the first colored resin layer.
The step of disposing the third colored resin layer on the corresponding third color pixel and overlapping the part of the second colored resin layer with the exposed peripheral portion of the first colored resin layer. The manufacturing method of the liquid crystal display device of Claim 2 characterized by the above-mentioned. The color filter layer includes a first colored resin layer colored in a first color, a second colored resin layer colored in a second color, and a third colored resin layer colored in a third color,
2. The method of manufacturing a liquid crystal display device according to claim 1, wherein the second colored resin layer and the third colored resin layer are arranged adjacent to each other in the row direction of the first colored resin layer. In the step of forming the color filter layer,
The first colored resin layer is arranged in a stripe shape over a plurality of first color pixels arranged along the corresponding column direction, and the peripheral portion along the row direction is formed to be thicker than the effective portion. ,
The second colored resin layer is arranged in a stripe shape over a plurality of second color pixels arranged along a corresponding column direction, and one peripheral portion along the column direction of the second colored resin layer The first colored resin layer is arranged so as to overlap with one peripheral edge along the column direction, and the peripheral edge along the row direction is formed to be thicker than the effective part,
The third colored resin layer is arranged in a stripe shape across a plurality of third color pixels arranged along the corresponding column direction, and the other peripheral edge portion along the column direction of the second colored resin layer and the The method further comprises a step of overlapping the other peripheral portion along the column direction of the first colored resin layer and forming the peripheral portion along the row direction in a film thickness thicker than the effective portion. 5. A method for producing a liquid crystal display device according to 4. In the step of disposing the first colored resin layer, the second colored resin layer, and the third colored resin layer,
Form a film of photosensitive colored resin material,
Exposing the photosensitive colored resin material at a first exposure amount corresponding to a first region that forms a peripheral portion along the row direction of each pixel;
Exposing the photosensitive colored resin material at a second exposure amount different from the first exposure amount corresponding to a second region forming another part of each pixel;
6. The method of manufacturing a liquid crystal display device according to claim 5, further comprising a step of developing the photosensitive colored resin material.   The liquid crystal according to claim 6, wherein the photosensitive colored resin material is collectively exposed using a photomask having different transmittances in patterns corresponding to the first region and the second region, respectively. Manufacturing method of display device. A liquid crystal layer is sandwiched between the first substrate and the second substrate,
The first substrate is
Switching elements arranged for each pixel;
A color filter layer composed of a plurality of colored resin layers colored in a plurality of colors, each color resin layer being arranged in a corresponding color pixel; and
A pixel electrode disposed on the color filter layer for each pixel and electrically connected to the switching element through a contact hole formed in the color filter layer;
The colored resin layer has a peripheral portion along the periphery of each pixel, and an effective portion having a film thickness thinner than the peripheral portion on the inner side surrounded by the peripheral portion,
The liquid crystal display device, wherein the pixel electrode is disposed on an effective portion of the colored resin layer, and a peripheral surface of the colored resin layer is substantially flat over the entire surface.

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