JP2004280006A - Liquid crystal display device and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the variation in the heights of spacers by preventing the deformation of the spacers due to baking treatment relating to a method for manufacturing a liquid crystal display device comprising simultaneously forming the spacers and projecting parts and to deform the projecting parts to desired shapes. <P>SOLUTION: The method for manufacturing the liquid crystal display device includes a process of forming a negative type photoresist layer 40 on a substrate, a first exposure process of exposing regions of the negative type photoresist layer 40 where the spacers 35 are formed and regions where the projecting parts 36 for controlling the pretilt of a liquid crystal material are formed by using a first mask 41, a process of developing the negative type photoresist layer 40, a second exposure process of exposing only the residual films remaining in the regions where the spacers 35 are formed by using a second mask 42 and expediting the hardening of the residual films of the above regions earlier than the hardening of the residual films of the regions where the projecting parts are formed, and a process of subjecting the substrate to baking treatment. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a liquid crystal display device using a vertical alignment type liquid crystal material.
[0002]
[Prior art]
2. Description of the Related Art In recent years, liquid crystal display devices have been required to improve response speed and visual characteristics, and as one of techniques for satisfying these requirements, a multi-vertical alignment (MVA) type liquid crystal using a vertical alignment type liquid crystal material is used. Display devices have been developed.
[0003]
In this MVA liquid crystal display device, a vertically aligned liquid crystal is sealed between a pair of substrates kept at a predetermined interval by a spacer. Projections for controlling the pretilt of the liquid crystal molecules are formed separately from the spacers on the substrate surface of the MVA liquid crystal display device. The projection is a dome-shaped projection or a hemispheric projection having a dome-shaped cross section, and is formed lower than the spacer. With the formation of the protrusion, the vertical alignment type liquid crystal molecules are vertically aligned with the surface of the dome-shaped protrusion, and thus have a pretilt with respect to the surface of the substrate. By giving the pre-tilt to the vertically aligned liquid crystal molecules, the visual characteristics can be improved and the response speed of the liquid crystal molecules can be improved.
[0004]
As described above, mainly on the substrate of the MVA type liquid crystal display device, the spacer for maintaining the space between the substrates (hereinafter, also referred to as “cell gap”) and the protrusion for controlling the pretilt are provided. In addition, a technique for simultaneously forming these two types of protrusions has been developed (see Patent Document 1).
[0005]
A method for manufacturing the liquid crystal display device described in Patent Document 1 will be described. FIG. 6 is a schematic view showing a manufacturing process of the liquid crystal display device of Patent Document 1. In the technique of Patent Document 1, as shown in FIG. 6A, a positive photoresist layer 200 is formed on the upper surface of a color filter substrate 100 constituting a liquid crystal cell. Next, as shown in FIG. 6B, a predetermined amount of ultraviolet rays is irradiated from the upper surface of the photoresist layer 200 using a mask 300 having an opening pattern corresponding to the shapes of the spacers and the protrusions. The mask 300 transmits ultraviolet light to a region other than the region where the spacer 400 and the protrusion 500 are formed, and exposes the positive photoresist layer 200. As shown in FIG. 6C, a predetermined amount of ultraviolet light is applied only from the exposed upper surface of the photoresist layer 200 to a region where the protrusion 500 is to be formed by using another mask 310 to perform exposure. .
[0006]
In this case, the region where the spacer 400 is formed and the region where the protrusion 500 is formed have different ultraviolet irradiation doses. That is, the region where the spacer 400 is formed is hardly irradiated with ultraviolet light, the region where the protrusion 500 is formed is slightly irradiated with ultraviolet light, and the other regions are sufficiently irradiated with ultraviolet light.
[0007]
As shown in FIG. 6D, the photoresist layer 200 in which each of the regions is irradiated with a predetermined amount of ultraviolet rays is developed. Since the photoresist layer 200 is formed of a positive resist, the resist in the region irradiated with the ultraviolet rays is removed by the developing process. Therefore, on the substrate, a spacer 400 whose height is equal to the initial thickness of the photoresist layer 200 and a projection 500 having a height lower than that of the spacer 400 are formed by slightly irradiating ultraviolet rays.
[0008]
After completion of the developing process, the substrate 100 is subjected to a post-baking process at a predetermined temperature, so that the spacer 400 and the protrusion 500 are cured. In this way, the spacers and projections having different heights are formed on one substrate.
[0009]
[Patent Document 1]
JP 2001-201750 A
[0010]
[Problems to be solved by the invention]
However, the method of manufacturing a liquid crystal display device described in Patent Document 1 has the following problems. The photoresist used in the above manufacturing method is a positive photoresist as described above. Therefore, the spacer formed by the developing process may be heated and deformed by the post-baking process.
[0011]
In other words, since the positive type photoresist is decomposed by the exposure to ultraviolet light, the regions corresponding to the spacers and the projections are not subjected to the curing action. Therefore, when the spacers and the protrusions are heated by the post-baking process, the resist may soften before being thermally cured. In particular, the resist forming the spacer is softened, causing a so-called “thermal sagging phenomenon”, which may cause variations in the height of the spacer. Such a variation in the height of the spacer causes the cell gap to become non-uniform, which lowers the display quality of the liquid crystal display device.
[0012]
In order to reduce variations in the height of the spacer due to the post-baking process, improvements have been made to increase the width of the spacer. By making the width of the spacer wider, it is possible to maintain the initial height of the spacer in the center where the influence of the heat sagging does not affect, while allowing the heat sagging at the outer edge of the spacer. However, when the width of the spacer is increased, there is a problem that the aperture ratio of the pixel is reduced and the screen display becomes dark.
[0013]
Therefore, the present invention relates to a method for manufacturing a liquid crystal display device in which a spacer having the above-mentioned predetermined height and a projection for controlling the pretilt of liquid crystal molecules are collectively formed. Another object of the present invention is to manufacture a highly reliable liquid crystal display device with high quality images by preventing variations in the height of the image and by deforming the projections into a desired shape.
[0014]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the present invention is a manufacturing method in which a negative photoresist is used as a material for forming the spacer and the projection, and the spacer and the projection can be formed at a time.
[0015]
Specifically, the present invention is a method for manufacturing a liquid crystal display device in which a liquid crystal material is sealed between a pair of opposing substrates, wherein a step of forming a negative photoresist layer on one of the substrates, A first exposure for exposing a region of the negative photoresist layer where a spacer for maintaining a cell gap between the substrates is formed and a region where a protrusion for controlling the pretilt of the liquid crystal material is formed; Developing the negative photoresist layer to form a residual film of the negative photoresist layer in a region where the spacers are formed and in a region where the protrusions are formed; A second exposure step of exposing only the residual film remaining in the region where the spacer is formed, and curing the residual film in the region more than curing the residual film in the region where the protrusions are formed. And the residual film is formed Baking process, the remaining film remaining in the region where the spacer is formed is cured to form the spacer, and the remaining film remaining in the region where the protrusion is formed is softened so that the cross-sectional shape is dome. Forming a projection of the mold.
[0016]
Further, the present invention is a method for manufacturing a liquid crystal display device in which a liquid crystal material is sealed between a pair of opposing substrates, wherein a step of forming a negative photoresist layer on one of the substrates and a method using a first mask are provided. A first exposure step of exposing a region of the negative photoresist layer where a spacer for maintaining a cell gap between the substrates is formed and a region where a protrusion for controlling pretilt of the liquid crystal material is formed. Using a second mask, exposing only the region of the negative photoresist layer where the spacer is formed, and curing the region more than the region where the protrusion is formed. An exposing step, a step of developing the negative photoresist layer and forming a residual film of the negative photoresist layer in a region where the spacer is formed and a region where the protrusion is formed; Formed The substrate is baked, the remaining film in the region where the spacers are formed is cured to form the spacers, and the remaining film in the region where the protrusions are formed is softened to form a dome-shaped cross section. Forming a protrusion of the liquid crystal display device.
[0017]
The present invention is the method for manufacturing a liquid crystal display device, wherein after the step of baking the substrate on which the residual film is formed and forming a projection having a dome-shaped cross section, a vertical alignment film is formed on the substrate. May be further included.
[0018]
The present invention is the method for manufacturing a liquid crystal display device, wherein, after the step of forming the vertical alignment film, a step of bonding the substrate to another substrate on which a vertical alignment film is formed in advance, The method may further include a step of sealing a vertical alignment type liquid crystal material between the pair of substrates.
[0019]
Further, the present invention is a liquid crystal display device manufactured by using any one of the manufacturing methods described above. These solve the above-mentioned problems.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0021]
In the liquid crystal display device 1 of the present embodiment shown in FIG. 1, a TFT (Thin Film Transistor) substrate 20 and a color filter substrate (hereinafter, referred to as a “CF substrate”) 30 are joined while maintaining a predetermined cell gap. I have. The liquid crystal display device 1 according to the present embodiment has a structure in which a vertically aligned liquid crystal material 2 is sealed in a cell gap between the substrates.
[0022]
The TFT substrate 20 includes a substrate 21 made of a transparent material such as glass, an active element 22, a pixel electrode (not shown), an insulating film (not shown), and an active element 22 formed on one surface of the substrate 21. It is composed of a vertical alignment film 23 and the like. Further, on the TFT substrate 20, the active element 22, a gate bus line (not shown) for applying a gate voltage and a source voltage to the pixel electrode, and a source bus line (not shown) are formed. .
[0023]
The active element 22 includes a silicon thin film serving as an active layer. On one surface of the silicon thin film, a gate electrode is formed by being laminated with the silicon thin film.
[0024]
On the other surface of the silicon thin film, a source electrode and a drain electrode are formed so as to face each other. The gate bus lines and the source bus lines are arranged to be orthogonal to each other. Each rectangular region defined by the gate bus line and the source bus line includes one pixel.
[0025]
On the surface of the TFT substrate 20 facing the CF substrate 30, a vertical alignment film 23 is formed.
[0026]
On the other hand, the CF substrate 30 includes a glass substrate 31, a black matrix 32 formed on the lower surface side of the glass substrate 31, a color filter layer 33, a vertical alignment film 37, and the like. In this embodiment, the CF substrate 30 is provided with a spacer 35 for maintaining a constant cell gap between the substrates and a projection 36 for pretilting the liquid crystal material.
[0027]
The black matrix 32 formed on one surface of the glass substrate 31 is made of a light-shielding thin film such as chrome.
[0028]
The color filter layer 33 is formed such that a red color filter 33R, a green color filter 33G, and a blue color filter 33B are regularly arranged on one surface of the glass substrate 31. Each of these color filters 33R, 33G, 33B is arranged at a position facing the pixel electrode of the TFT substrate 20, and one of the red, green or blue color filters 33R, 33G, 33B is provided on one pixel electrode. Two color filters correspond. The black matrix 32 is disposed so as to cover a boundary region between the color filters 33R, 33G, and 33B.
[0029]
A transparent electrode 34 made of ITO (Indium Tin Oxide) is formed so as to cover the upper surfaces of the black matrix 32 and the color filters 33R, 33G, 33B. The spacer 35 and the protrusion 36 are formed on the upper surface of the transparent electrode 34.
[0030]
The spacer 35 in the present embodiment is a quadrangular prism-shaped protrusion, and has sufficient strength to maintain a cell gap. However, the shape of the spacer 35 is not limited to a quadrangular prism shape, and may be a cylindrical shape, a polygonal truncated cone shape, a truncated cone shape, or the like as long as the cell gap can be stably maintained. The spacer 35 is formed of a negative photoresist as described later.
[0031]
The protrusion 36 in the present embodiment is a so-called dome-shaped ridge member as shown in FIG. As shown in FIG. 2, the protrusions 36 are formed in a zigzag on the transparent electrodes 34 of the CF substrate 30. The height of the protrusion 36 is formed lower than the height of the spacer 35. However, the shape of the projection is not limited to a dome-shaped ridge, and may be a hemispherical projection as shown in FIG. The protrusion 36 is formed of a negative photoresist as described later.
[0032]
As shown in FIG. 1, the TFT substrate 20 and the CF substrate 30 are joined to face each other with the spacer 35 interposed therebetween. The upper end of each spacer 35 formed on the CF substrate contacts the vertical alignment film 23 near the intersection of the gate bus line and the source bus line formed on the TFT substrate 20. The upper end of the spacer 35 is not limited to the vicinity of the intersection, but may be in contact with an opaque region such as a gate bus line, a source bus line, or an auxiliary electrode (not shown). Thereby, the spacer 35 does not disturb the alignment of the liquid crystal molecules in the display area, and there is no possibility that the screen display is adversely affected.
[0033]
Next, a method for manufacturing the liquid crystal display device according to the present embodiment will be described.
[0034]
FIG. 4 is a view showing a process of manufacturing the CF substrate 30 of the liquid crystal display device 1 according to the present embodiment. FIG. 4A shows the CF substrate 30 before the spacer 35 and the protrusion 36 are formed. The production of the CF substrate will be outlined. A thin film having a light-shielding property is formed on one entire surface of the glass substrate 31. As the thin film, a metal thin film such as Cr is usually used. A photoresist is applied on the metal thin film, and the photoresist is exposed using a photomask that transfers the shape of a black matrix. By developing the exposed substrate, a black matrix 32 having a predetermined shape (typically, a square shape or the like) is formed on the substrate.
[0035]
Next, a color filter of each color is formed in a region defined by the black matrix 32. Specifically, a photoresist colored red is applied to the entire surface of the substrate from above the black matrix 32, and the photoresist is exposed using a photomask having an opening pattern corresponding to the shape of the color filter. By developing the exposed substrate, a red color filter 33R is formed on the substrate. Similarly, using a green photoresist and a blue photoresist, a green color filter 33G and a blue color filter 33B are formed on the substrate. Thus, the color filter layer 33 is formed.
[0036]
Next, a transparent electrode 34 made of an ITO film is formed on the upper surface of the color filter layer 33. For forming the transparent electrode 34, a sputtering method or the like is used.
[0037]
Next, a process of forming the spacer 35 and the protrusion 36 will be described.
[0038]
As shown in FIG. 4A, a negative photoresist is applied to a predetermined thickness from above the transparent electrode 34 of the CF substrate 30 by spin coating or the like. The applied negative photoresist is subjected to a pre-baking process to form a negative photoresist layer 40. As shown in FIG. 4B, the first mask 41 is used to place the negative photoresist layer 40 in the region where the spacer 35 is formed and the region where the protrusion 36 is formed. Irradiate a fixed amount of ultraviolet light. By irradiating ultraviolet rays in the first exposure step, the negative photoresist in each of the above-mentioned regions starts to be hardened, and forms a latent image of the above-mentioned spacers and projections. It is necessary to limit the exposure amount in the first exposure step to such an extent that the curing of the negative photoresist layer 40 by exposure does not reach saturation.
[0039]
Next, the negative photoresist layer 40 after the first exposure step is developed. As shown in FIG. 4C, the remaining film 50 having substantially the same thickness is formed on the transparent electrode 34 in the region where the spacer 35 is formed and the region where the protrusion 36 is formed by the developing process. , 51 remain.
[0040]
Next, as shown in FIG. 4D, a second exposure is performed on the substrate after the development processing. In the second exposure step, the second mask 42 is used to irradiate only the remaining film 50 of the remaining films 50 and 51 remaining on the substrate with the ultraviolet rays in the region where the spacer is to be formed. The remaining film 51 remaining in the region where the protrusion is formed is shielded from light by the second mask 42 and is not irradiated with ultraviolet rays. Thereby, the hardening of the remaining film 50 remaining in the region where the spacer is formed is promoted more than the hardening of the remaining film 51 left so as to form the protrusion. The exposure amount in the second exposure step is sufficient to cure the residual film 50 corresponding to the spacer so as not to cause the heat sagging phenomenon in the subsequent baking process.
[0041]
Next, as shown in FIG. 4E, a baking process is performed on the substrate after the second exposure process. The CF substrate 30 is placed in a heating furnace and is heated at a predetermined temperature for a predetermined time. As shown in FIG. 5, the remaining film 50 remaining in the region where the spacer is formed is sufficiently hardened in the second exposure step, so that the remaining film 50 is slightly shrunk without causing heat sagging. The spacer 35 is cured by heat.
[0042]
On the other hand, the remaining film 51 remaining in the region where the protrusion is formed is only exposed in the first exposure step and is not sufficiently cured. For this reason, when heated in the baking process, the material softens and a heat sag phenomenon occurs before the thermosetting starts. As described above, when the residual film 51 corresponding to the protruding portion causes the heat sagging phenomenon, the cross-sectional shape which was initially rectangular gradually changes to a dome shape. In addition, the height gradually decreases with such deformation. The residual film 51 is deformed into a dome-shaped projection with a cross-sectional shape, and then thermally cured to form the projection 36 for controlling the pretilt.
[0043]
Next, a vertical alignment film is formed on the entire surface of the CF substrate 30 from above the spacer 35 and the protrusion 36.
[0044]
The thus formed CF substrate 30 is joined to the previously formed TFT substrate 20 as shown in FIG. The two substrates face each other on the surfaces of the substrates on which the vertical alignment films 23 and 37 are formed, and the leading end of the spacer 35 is placed in an opaque region of the TFT substrate 20 (for example, at the intersection of a gate bus line and a data bus line). ). A sealing material (not shown) made of epoxy resin or the like is applied to the outside of the display area of one of the TFT substrate 20 and the CF substrate 30, and the TFT substrate 20 and the CF substrate 30 are coated with the sealing material. The substrate 30 is joined.
[0045]
Next, a vertical alignment type liquid crystal material is injected into a cell gap between the TFT substrate 20 and the CF substrate 30. The liquid crystal material is injected by a conventional injection method such as a reduced pressure injection method or a normal pressure injection method. When the liquid crystal material is filled in the cell gap, the injection port is sealed with an epoxy resin or the like. Thus, the liquid crystal display device 1 according to the present embodiment is manufactured.
[0046]
The operation and effect of the liquid crystal display device according to the present embodiment and the method for manufacturing the same will be described.
[0047]
In the present embodiment, the spacer 35 and the protrusion 36 can be formed collectively through the first exposure step, the second exposure step, and the development processing using a photoresist. Therefore, the manufacturing method according to the present embodiment does not increase the number of steps as compared with the conventional manufacturing method.
[0048]
Further, in the manufacturing method according to the present embodiment, the first exposure and the second exposure are selectively performed using a negative photoresist as the photoresist. Therefore, when baking is performed on the remaining film formed on the substrate, the remaining film 50 corresponding to the spacer is thermally cured without causing the heat sagging phenomenon, and the height of the spacer 35 does not vary. Therefore, the liquid crystal display device according to the present embodiment can make the cell gap uniform with high accuracy, and can realize high display quality and reliability.
[0049]
In the past, when a positive photoresist was used, the width of the spacer was designed to be wide in consideration of the heat sagging phenomenon in the baking process. However, in the liquid crystal display device according to the present embodiment, by using the negative photoresist, it is not necessary to design the width of the spacer to be large in consideration of heat sag. As a result, a bright screen display can be realized because the aperture ratio of the pixel is not reduced.
[0050]
On the other hand, the remaining film 51 corresponding to the protrusions can have a dome-shaped cross section by utilizing the heat sagging phenomenon caused by the baking process. The vertically aligned liquid crystal molecules filling the cell gap are pretilted and aligned in the normal direction of the dome shape. Therefore, the response speed when a voltage is applied between the substrates can be improved. Further, the projections 36 also have the effect of improving the visual characteristics of screen display.
[0051]
【Example】
An example of the method for manufacturing a liquid crystal display device according to the present invention will be described.
[0052]
The present embodiment shown in FIG. 3 will be described with respect to the production of the CF substrate. A method for manufacturing a TFT substrate, a method for bonding the substrates, a method for injecting a liquid crystal material, and the like used in the liquid crystal display device can be appropriately selected from conventional methods. As shown in FIG. 3, the spacer according to the present embodiment has a cylindrical shape with a diameter of 15 μm, and the protrusion according to the present embodiment has a circular dome shape with a diameter of 10 μm.
[0053]
First, a black matrix made of a chromium (Cr) thin film was formed on a glass substrate by photolithography. Next, from above the black matrix, using a colored photoresist (Fuji Film Olin: Color Mosaic Black: CM-K, Red: CM-R, Green: CM-G, Blue: CM-B), and photolithography. Each color filter of red, green and blue was prepared by the method. Next, a transparent electrode of an ITO thin film was formed from above the color filter layer by a sputtering method.
[0054]
Next, a spacer and a projection were formed on the transparent electrode. In this embodiment, a negative photoresist (Optomer AL, manufactured by JSR Corporation) was used as a material for the spacer and the projection. This photoresist was applied on the surface of the transparent electrode to a thickness of 3 μm by spin coating.
[0055]
Thereafter, the photoresist layer was irradiated with ultraviolet rays of 60 (mJ) through the first mask to expose predetermined spacer shapes and protrusion shapes (first exposure step).
[0056]
After the first exposure step, a columnar residual film having a diameter of 15 μm is formed in a region where a spacer is formed using an alkaline developer, and a residual film having a diameter of 8 μm is formed in a region where a protrusion is formed. did.
[0057]
After the developing step, only the remaining film corresponding to the spacer was selectively irradiated with 1000 mJ of ultraviolet light using a second photomask to perform exposure (second exposure). By the second exposure step, the surface of the remaining film corresponding to the spacer was sufficiently cured.
[0058]
After the second exposure step, the substrate was baked using a heating furnace. In this example, baking was performed at 230 ° C. for 60 minutes. As a result of this baking treatment, the surface of the residual film corresponding to the spacer is hardened sufficiently, so that the sagging phenomenon does not occur, and the shrinkage in the height direction is slightly maintained, but the shape of the remaining film is maintained as it is. Thus, the columnar spacer 35 was obtained.
[0059]
On the other hand, the remaining film corresponding to the protrusions not subjected to the second exposure began to soften before the thermosetting occurred under the above-mentioned firing conditions, causing a heat sagging phenomenon. Due to this heat sagging phenomenon, the residual film was reduced in height and deformed from a cylindrical shape to a dome shape. When heating was continued in this state, the remaining film softened and deformed by the heat sagging phenomenon began to harden, and finally a circular dome-shaped projection 36 was obtained.
[0060]
In this embodiment, the spacer was a column having a diameter of 15 μm and a height of 2.9 μm, and the protrusion was a circular dome having a diameter of 10 μm and a height of 2.5 μm.
[0061]
Next, an alignment film material for vertical alignment was applied to the surface of the CF substrate on which the spacers and the protrusions were formed, to form a vertical alignment film.
[0062]
The target liquid crystal display device was obtained by bonding the thus obtained CF substrate and the TFT substrate and sealing the vertical alignment type liquid crystal material in the cell gap.
[0063]
As described above, the embodiments of the present invention have been described with reference to the drawings and the examples. However, the present invention is not limited to the above embodiment, but can be realized by other embodiments.
[0064]
For example, as another embodiment, in the method for manufacturing a liquid crystal display device, the step of developing the negative photoresist layer formed on the CF substrate may be after the second exposure step.
[0065]
That is, similarly to the method of manufacturing the liquid crystal display device, first, a negative photoresist layer is formed on one of the opposing substrates.
[0066]
Next, using a first mask, a region of the negative photoresist layer where a spacer for maintaining a cell gap between the substrates is formed and a region where a protrusion for controlling the pretilt of the liquid crystal material is formed. First exposure is performed.
[0067]
Next, in the above embodiment, the developing step is performed, but in the present embodiment, the second exposure step is performed. That is, a second mask is used to expose only the region of the negative photoresist layer where the spacer is formed, and to cure the region more than the region where the protrusions are formed. An exposure step is performed.
[0068]
Next, a step of developing the negative photoresist layer and forming a residual film of the negative photoresist layer in a region where the spacer is formed and a region where the protrusion is formed is performed. In this state, the remaining film corresponding to the spacer has undergone the first exposure and the second exposure, whereas the remaining film corresponding to the protrusion has only undergone the first exposure. Therefore, the hardening of the remaining film corresponding to the spacer is promoted more than the hardening of the remaining film corresponding to the protrusion.
[0069]
Next, similarly to the above embodiment, the substrate on which the residual film is formed is baked, and the residual film remaining in the region where the spacer is formed is cured to form the spacer, and the protrusion is formed. A step of softening the remaining film remaining in the region to form a projection having a dome-shaped cross section is performed.
[0070]
The CF substrate according to the present embodiment obtained in this manner is subjected to the steps of forming a vertical alignment film, bonding to a TFT substrate, and enclosing a vertical alignment type liquid crystal material in the same manner as in the above-described embodiment. It becomes a display device.
[0071]
The liquid crystal display device according to the present embodiment also has effects such as a bright and high-quality screen display, a fast response speed, and high reliability, similarly to the liquid crystal display device according to the above embodiment.
[0072]
【The invention's effect】
According to the present invention, a spacer for maintaining a cell gap and a projection for controlling a pretilt of a liquid crystal material can be collectively formed without increasing the number of manufacturing steps. Further, according to the present invention, since a negative type photoresist is used as a material for forming the spacer and the protrusion, the height of the spacer can be made uniform with high precision, and a heat sag phenomenon during a baking process can be achieved. Need not be taken into account, and it is no longer necessary to increase the width of the spacer. As a result, the brightness of the screen display can be improved, and a high-quality screen display can be realized.
[0073]
In addition, the response speed of the vertically aligned liquid crystal molecules can be improved and the viewing angle characteristics of the screen can be improved by the projections formed simultaneously with the spacers.
[Brief description of the drawings]
FIG. 1 is a sectional view of a main part of a liquid crystal display device according to the present invention.
FIG. 2 is an enlarged plan view of a CF substrate of the liquid crystal display device according to the present invention.
FIG. 3 is an enlarged plan view of a CF substrate of the liquid crystal display device according to the present invention.
FIG. 4 is a diagram illustrating a method for manufacturing a liquid crystal display device according to the present invention.
FIG. 5 is a diagram for explaining the effect of the spacer and the protrusion on the baking process according to the present invention.
FIG. 6 is a diagram illustrating a conventional method for manufacturing a liquid crystal display device.
[Explanation of symbols]
1 Liquid crystal display device
20 TFT substrate
23 Vertical alignment film
30 CF substrate
35 Spacer
36 Projection
40 Negative photoresist layer
41 First Mask
42 Second Mask

Claims (5)

A method for manufacturing a liquid crystal display device in which a liquid crystal material is sealed between a pair of opposed substrates,
Forming a negative photoresist layer on one of the substrates;
Using a first mask, exposure is performed on a region of the negative photoresist layer where a spacer for maintaining a cell gap between the substrates is formed and a region where a protrusion for controlling pretilt of the liquid crystal material is formed. A first exposure step,
Developing the negative photoresist layer, forming a residual film of the negative photoresist layer in the region where the spacer is formed and the region where the protrusion is formed;
Using the second mask, only the remaining film remaining in the region where the spacer is formed is exposed, and the hardening of the remaining film in the region is accelerated more than the hardening of the remaining film in the region where the protrusion is formed. A second exposure step;
The substrate on which the remaining film is formed is baked, and the remaining film remaining in the region where the spacer is formed is cured to form the spacer, and the remaining film remaining in the region where the protrusion is formed is softened. Forming a projection having a dome-shaped cross section. A method for manufacturing a liquid crystal display device in which a liquid crystal material is sealed between a pair of opposed substrates,
Forming a negative photoresist layer on one of the substrates;
Using a first mask, exposure is performed on a region of the negative photoresist layer where a spacer for maintaining a cell gap between the substrates is formed and a region where a protrusion for controlling pretilt of the liquid crystal material is formed. A first exposure step,
Using a second mask, exposing only the region of the negative photoresist layer where the spacers are to be formed, and curing the region more than the region where the protrusions are to be formed; When,
Developing the negative photoresist layer, forming a residual film of the negative photoresist layer in the region where the spacer is formed and the region where the protrusion is formed;
The substrate on which the remaining film is formed is baked, and the remaining film remaining in the region where the spacer is formed is cured to form the spacer, and the remaining film remaining in the region where the protrusion is formed is softened. Forming a projection having a dome-shaped cross section. After the step of baking the substrate on which the residual film is formed, and forming a projection having a dome-shaped cross section,
The method for manufacturing a liquid crystal display device according to claim 1, further comprising a step of forming a vertical alignment film on the substrate. After the step of forming the vertical alignment film,
Bonding the substrate to another substrate on which a vertical alignment film has been formed in advance;
The method of manufacturing a liquid crystal display device according to claim 4, further comprising a step of enclosing a vertical alignment type liquid crystal material between the pair of substrates bonded to each other. A liquid crystal display device manufactured by using the method of manufacturing a liquid crystal display device according to claim 1.

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