JP2007094064A - Method for manufacturing color filter for liquid crystal display device and color filter for liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a color filter for a liquid crystal display device by which an orientation control projection Mv and two kinds of photospacers Ps-1, Ps-2 are simultaneously and simply formed by one process of a photolithography method using one kind of photopolymers. <P>SOLUTION: A photosensitive resin layer 60 is formed on a transparent substrate 40 on which a black matrix, colored pixels and a transparent conductive film are formed, when exposure is performed via a photomask PM in which a pattern corresponding to the orientation control projection, a first photospacer and the second photospacer is formed, proximity exposure by providing a sufficient gap is performed and the orientation control projection, the first photospacer and the second photospacer are simultaneously formed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to the manufacture of a color filter for a liquid crystal display device, and more particularly to a method for manufacturing a color filter for a liquid crystal display device in which an alignment control protrusion and a photospacer are formed simultaneously.
The present invention also relates to a color filter for a liquid crystal display device manufactured by the above manufacturing method.

FIG. 4 is a plan view schematically showing an example of a color filter used in the liquid crystal display device. FIG. 5 is a cross-sectional view taken along the line XX ′ of the color filter shown in FIG.
As shown in FIGS. 4 and 5, the color filter (4) used in the liquid crystal display device has a black matrix (41), a colored pixel (42), and a transparent conductive film (43) on a glass substrate (40). Are formed sequentially.
4 and 5 schematically show a color filter, and 12 colored pixels (42) are represented. In an actual color filter, for example, several hundreds are displayed on a 17-inch diagonal screen. A large number of colored pixels of about μm are arranged.

As a method for manufacturing a color filter having the above structure used in many liquid crystal display devices, a black matrix is first formed on a glass substrate to form a black matrix substrate, and then the black matrix on the black matrix substrate is used. A method is widely used in which a colored pixel is formed by aligning with the pattern, and a transparent conductive film is aligned and formed.
The black matrix (41) is a matrix having light shielding properties, the colored pixels (42) have, for example, red, green, and blue filter functions, and the transparent conductive film (43) is transparent. Provided as a simple electrode.

The black matrix (41) is composed of a matrix portion (41A) between the colored pixels (42) and a frame portion (41B) surrounding the peripheral portion of the region (display portion) where the colored pixels (42) are formed. Yes.
The black matrix determines the position of the colored pixels of the color filter, makes the size uniform, and shields unwanted light when used in a display device, making the image of the display device uniform and uniform. In addition, it has a function of making an image with improved contrast.

For the production of this black matrix substrate, a metal or a metal compound such as chromium (Cr) or chromium oxide (CrO _x ) as a black matrix material is formed into a thin film on a glass substrate (40). An etching resist pattern is formed on the formed thin film using, for example, a positive photoresist, and then an exposed portion of the formed metal thin film is etched and an etching resist pattern is stripped, and Cr, CrO _A method has been adopted in which a black matrix (41) made of a metal thin film such as _X is formed.
Alternatively, the black matrix (41) is formed on the glass substrate (40) by photolithography using a black photosensitive resin for forming a black matrix.

In addition, the colored pixels (42) are formed by providing a coating film on the black matrix substrate using, for example, a negative photoresist in which a pigment or other pigment is dispersed, and exposing and developing the coating film. A method of forming colored pixels is used.
The transparent conductive film (43) is formed on the black matrix substrate on which the colored pixels are formed by, for example, forming a transparent conductive film by sputtering using ITO (Indium Tin Oxide). .

The color filter (4) shown in FIGS. 4 and 5 has a basic function as a color filter used in a liquid crystal display device. By incorporating such color filters, the liquid crystal display device realizes full color display, and its application range has expanded dramatically, creating many products using liquid crystal display devices such as liquid crystal color TVs and notebook PCs. It was done.
With the development and practical use of various liquid crystal display devices, the following various functions have been added to the color filters used in the liquid crystal display devices in addition to the above basic functions.

For example, orientation division function. In conventional liquid crystal display devices, in order to uniformly align the liquid crystal molecules, polyimide is applied in advance on the transparent conductive film provided on both substrates sandwiching the liquid crystal, and the surface is uniformly rubbed. Process it.
However, in TN type liquid crystal, it is difficult in principle to obtain a wide viewing angle, the contrast is lowered, and the display quality is deteriorated. There was a problem that the viewing angle with good contrast was narrow.

  As a technique for solving such a problem, an alignment-divided vertical alignment type liquid crystal display device having a wide viewing angle by controlling the alignment direction of liquid crystal molecules in one pixel to be a plurality of directions instead of one direction ( MVA (Multi-domain Vertical Alignment) -LCD has been developed.

  FIG. 7 is an explanatory view schematically showing a cross section of such an MVA-LCD. As shown in FIG. 7, the MVA-LCD (80) includes a TFT side substrate (20) provided with alignment control protrusions (22a) and (22b) via liquid crystal molecules (21), and an alignment control protrusion (23 ) Are arranged, and the alignment control protrusions (22a) and (22b) and the alignment control protrusion (23) are provided at alternate positions in one pixel.

  As shown by the white arrow in FIG. 7, in the state at the time of voltage application, the liquid crystal molecules between the alignment control protrusions (22a) to the alignment control protrusions (23) in the pixel are inclined obliquely to the left in the drawing. The liquid crystal molecules between the control protrusion (23) and the alignment control protrusion (22b) are inclined obliquely to the right. That is, the alignment of the liquid crystal molecules is controlled by providing protrusions instead of the rubbing treatment.

FIGS. 8A and 8B are an enlarged plan view and a cross-sectional view illustrating an example of a color filter used in the MVA-LCD. In this example, the orientation control protrusion (83) is bent 90 ° within one pixel.
FIGS. 9A and 9B are a plan view and a cross-sectional view showing an enlarged view of one pixel of another example. As shown in FIGS. 9A and 9B, another example is a color filter (9) in which an orientation control protrusion (93) having a circular planar shape is formed.
In a liquid crystal display device using such a color filter, the tilt directions of liquid crystal molecules are multidirectional within one pixel.

Moreover, as a function added accompanying the said basic function, for example, a spacer function. In a conventional liquid crystal display device, transparent spherical particles (beads) of glass or synthetic resin called spacers are dispersed to form a gap between substrates.
Since these spacers are transparent particles, if a spacer is included with the liquid crystal in the pixel, light will leak through the spacer during black display, and the substrate in which the liquid crystal material is enclosed Due to the presence of the spacers between them, the alignment of the liquid crystal molecules in the vicinity of the spacers is disturbed, and light leakage occurs at this part, and the contrast is lowered and the display quality is adversely affected.

As a technique for solving such a problem, a method of forming a photo spacer (protrusion) having a spacer function at a position of a black matrix between pixels by using a photosensitive resin and by a photolithography method has been developed.
FIG. 6 is a partial cross-sectional view of such a color filter for a liquid crystal display device. As shown in FIG. 6, in the color filter (7) for the liquid crystal display device, a black matrix (41), a colored pixel (42), and a transparent conductive film (43) are sequentially formed on a glass substrate (40). A photospacer (44) as a protrusion having a spacer function is formed on the transparent conductive film (43) above the black matrix (41). In the liquid crystal display device using such a color filter (7) for the liquid crystal display device, the photo spacer (44) is formed at a position avoiding the inside of the pixel, and thus the contrast is improved.

  The cross-sectional shape of the alignment control protrusion (83) having a planar shape in a stripe shape along the line AA is, for example, a triangle or a kamaboko shape, its width (W2) is about 9 to 12 μm, and its height (H2) is It is about 0.8 to 1.7 μm. In addition, the width (W3) and height (H3) of the orientation control protrusion (93) having a circular planar shape are substantially the same as those of the stripe-like orientation control protrusion (83). These are formed using a transparent photosensitive resin.

Further, the height of the photo spacer (44) is about 2 μm to 5 μm which is a gap between substrates, and the shape thereof is a rounded rectangle with a horizontal section of diagonal length (15 × 15 μm) to (40 × 40 μm), Lozenges are often used.
In the panel assembly process, when applying pressure to the color filter for a liquid crystal display device and applying pressure, if the hardness of the photo spacer is hard, the gap between the substrates is difficult to be uniform due to uneven pressing pressure, Color unevenness or the like is likely to occur in the liquid crystal display device. Therefore, the photo spacer needs to be elastic to be deformed by a load.

That is, the photospacer needs to have a restoring force that deforms when a load is applied and restores when the load is removed.
The restoration rate in the present invention is the amount (elastic deformation amount) restored when the load is removed relative to the total deformation amount when the load is applied, and it can be said that the restoration rate is preferably 60% or more. (Restoration rate = elastic deformation / total deformation)
On the other hand, when a finger touches the surface of the liquid crystal display device and local finger pressure is applied, local color unevenness may occur. In order to avoid the occurrence of such color unevenness, the photo spacer is preferably hard.

FIG. 3 is a cross-sectional view schematically showing an example of a color filter for a liquid crystal display device provided with two types of photo spacers in order to improve the pressure resistance of the liquid crystal display device. As shown in FIG. 3, this color filter for a liquid crystal display device has a black matrix (41), a colored pixel (42), a transparent electrode layer (43), and an alignment control protrusion (Mv) on a glass substrate (40). A photo spacer is formed.
As the photospacer, a first photospacer (Ps-1) and a second photospacer (Ps-2) having a height lower than that of the first photospacer are formed.

As functions added to the color filter (4) shown in FIG. 4, in addition to the orientation dividing function and spacer function, a high reliability function, a combined transmission / reflection function, a spectral characteristic adjustment function, an optical path difference adjustment function, For example, light scattering function. Among these functions, one function or a plurality of functions are added to the color filter (4) shown in FIG. 4 based on the use and specification of the color filter.
Therefore, for example, when manufacturing a color filter having a specification in which an orientation dividing function and a spacer function are added to the color filter (4) shown in FIG. 4, after producing the color filter (4) shown in FIG. Then, the alignment control protrusion (93) shown in FIG. 9 is formed, and then the photo spacer (44) shown in FIG. 6 is formed.

  That is, two steps of forming an alignment control protrusion and a step of forming a photo spacer are added, or in the color filter shown in FIG. 3, the step of forming the alignment control protrusion (Mv) and the first photo Three steps, the step of forming the spacer (Ps-1) and the step of forming the second photospacer (Ps-2), are added, and a color filter having a desired specification is manufactured.

Since the photospacer and the alignment control protrusion have different heights and physical properties, two different types of photosensitive resins are used, and the photolithographic method is used in two steps.
For example, a transparent novolac photosensitive resin, which is a positive photosensitive resin, is used to form the photo spacer, and a transparent acrylic resin, which is a negative photosensitive resin, is used to form the alignment control protrusion, for example. A photosensitive resin is used.

As a technique for forming photo spacers and alignment control protrusions in one step using one type of photosensitive resin without using two different types of photosensitive resins, for example, in Japanese Patent No. 3255107, A technique is disclosed in which a colored layer of a color filter is laminated, a photo spacer is formed thereon, and an alignment control protrusion is simultaneously formed on the single colored layer of the color filter.
However, in general, the color layer of the color filter has certain restrictions on the film thickness in terms of color characteristics. Therefore, the stacking height of the colored layer is a height that is subject to the restrictions, and the height of the photo spacer from the colored layer surface of the color filter and the height of the alignment control protrusion are simultaneously formed to the desired height. Is difficult.
Japanese Patent No. 3255107 JP 2005-3854 A Japanese Patent Laid-Open No. 11-344700 JP 2001-512266 A JP 2002-236371 A

The present invention has been made to solve the above-described problem. In a method for manufacturing a color filter for a liquid crystal display device provided with an alignment control protrusion and two types of photospacers, a photopolymer is used and a photopolymer is used. A liquid crystal display capable of manufacturing a color filter for a liquid crystal display device in which an alignment control protrusion and two types of photo spacers are simultaneously and easily formed in one step of a lithography method, and the alignment control protrusion and two types of photo spacers are provided at low cost. It is an object of the present invention to provide a method for manufacturing a color filter for an apparatus.
It is another object of the present invention to provide a color filter for a liquid crystal display device manufactured using the method for manufacturing a color filter for a liquid crystal display device.

The present invention relates to a method for producing a color filter for a liquid crystal display device in which a black matrix, a colored pixel, a transparent conductive film, an alignment control protrusion, a first photo spacer, and a second photo spacer are formed on a transparent substrate.
1) A photosensitive resin layer is formed by applying a photosensitive resin on the transparent substrate on which the black matrix, the colored pixels, and the transparent conductive film are formed.
2) When performing exposure through the photomask on which the pattern corresponding to the orientation control protrusion, the first photospacer, and the second photospacer having a height lower than the first photospacer is formed, the photosensitive resin Proximity exposure with a gap between the upper surface of the layer and the film surface of the photomask is performed,
A method for producing a color filter for a liquid crystal display device, wherein a development process is performed to simultaneously form an alignment control protrusion, a first photo spacer, and a second photo spacer having a height lower than the first photo spacer.

  The present invention also provides the method for producing a color filter for a liquid crystal display device according to the above invention, wherein the photosensitive resin is a positive photosensitive resin. .

  Further, the present invention is the method of manufacturing a color filter for a liquid crystal display device according to the above invention, wherein the gap of the proximity exposure has a horizontal cross section of the first photo spacer of 25 μm × 25 μm or more and a horizontal cross section of the second photo spacer. A method for producing a color filter for a liquid crystal display device, characterized in that when the width is 15 μm to 25 μm and the width of the alignment control protrusion is 9 μm to 12 μm, the width is 70 μm to 300 μm.

  Moreover, this invention is manufactured using the manufacturing method of the color filter for liquid crystal display devices of any one of Claims 1-3, The color filter for liquid crystal display devices characterized by the above-mentioned.

  In the present invention, a photosensitive resin layer is formed by applying a photosensitive resin on a transparent substrate on which a black matrix, colored pixels, and a transparent conductive film are formed, and 2) an alignment control protrusion, a first photospacer, And when exposure is performed through a photomask having a pattern corresponding to the second photospacer having a height lower than that of the first photospacer, between the upper surface of the photosensitive resin layer and the film surface of the photomask. A method for producing a color filter for a liquid crystal display device, wherein proximity exposure with a gap is performed and development processing is performed to simultaneously form an alignment control protrusion, a first photo spacer, and a second photo spacer having a height lower than that of the first photo spacer. Therefore, a color filter for a liquid crystal display device capable of manufacturing a color filter for a liquid crystal display device provided with an alignment control protrusion and two types of photo spacers at low cost. A method of manufacturing a filter.

  In addition, since a positive photosensitive resin is used in the present invention, simultaneous formation of the alignment control protrusion, the first photo spacer, and the second photo spacer is facilitated. Further, the gap of the proximity exposure is such that the horizontal cross section of the first photo spacer is 25 μm × 25 μm or more, the horizontal cross section of the second photo spacer is 15 μm to 25 μm square, and the width of the alignment control protrusion is 9 μm to 12 μm. Since it is 70 μm to 300 μm, a difference in height between the orientation control protrusion, the first photo spacer, and the second photo spacer, which is lower than the first photo spacer, can be easily obtained, and it has a restoration rate as a photo spacer. Will be.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is a cross-sectional view illustrating proximity exposure in an embodiment of a method for producing a color filter for a liquid crystal display device according to the present invention. As shown in FIG. 1, a photosensitive resin layer (60) is formed on a glass substrate (40) on which a black matrix (41), a colored pixel (42), and a transparent conductive film (43) are sequentially formed. Above that, a photomask (PM) is arranged with a gap (G) for proximity exposure.
On the photomask (PM), a pattern corresponding to the formation of the alignment control protrusion, the first photospacer, and the second photospacer having a height lower than that of the first photospacer is formed. The film surface (51) of the photomask faces the photosensitive resin layer (60).

FIG. 2 is a cross-sectional view showing the alignment control protrusion (Mv), the first photospacer (Ps-1), and the second photospacer (Ps-2) obtained by the development processing after exposure.
The height (H6) and width (W6) of the orientation control protrusion (Mv), the height (H4) and width (W4) of the first photospacer (Ps-1), and the second photospacer (Ps-2) As shown in FIG. 2, the relationship between the height (H5) and the width (W5) is such that the height is H4>H5> H6 and the width is W4>W5> W6.

  Further, the width of the light-shielding portion of the photomask (PM) shown in FIG. 1 used for these formations is the width (W6) of the alignment control protrusion (Mv) and the width (W4) of the first photospacer (Ps-1), respectively. ), Corresponding to the width (W5) of the second photospacer (Ps-2), the width (W4) of the light shielding portion (S4)> the width (W5) of the light shielding portion (S5)> the width of the light shielding portion (S6) ( W6).

  In FIG. 1, exposure light (L) from above the photomask (PM) is irradiated to the photosensitive resin layer (60) through the light transmission portion of the photomask, but the proximity exposure gap (G) is sufficient. In this case, the irradiated light is not only in the photosensitive resin layer (60) portion below the light transmitting portion, but also the light irradiated by the diffraction of the irradiated light is exposed below the light shielding portion of the photomask. For example, when the photosensitive resin used is a positive photosensitive resin, it is photodegraded into a soluble material in the developer.

The diffracted light is small below the light-shielding portion (S4) having a large width corresponding to the first photospacer (Ps-1) having a large width (W4) shown in FIG. 2, and the width (W5) is a width. (W4) It increases below the light-shielding part (S5) having a width (W5) corresponding to the second photospacer (Ps-2) smaller than (W4).
The diffracted light further increases below the light shielding portion (S6) having the width (W6) corresponding to the alignment control protrusion (Mv) having the width (W6) smaller than the width (W5).

Accordingly, the amount of photodecomposition is small in the photosensitive resin layer (60) portion below the light shielding portion (S4) corresponding to the first photo spacer (Ps-1) having a large width (W4), and the width (W5) is small. In the photosensitive resin layer (60) part below the light shielding part (S5) corresponding to the second photospacer (Ps-2) smaller than the width (W4), the amount of photodecomposition increases.
Further, the amount of photodecomposition is further increased in the photosensitive resin layer (60) portion below the light shielding portion (S6) corresponding to the alignment control protrusion (Mv) having the width (W6) smaller than the width (W5).

  The dotted lines shown in FIG. 1 are not photodegraded by the diffraction of the irradiated light, that is, correspond to the alignment control protrusion (Mv), the first photospacer (Ps-1), and the second photospacer (Ps-2). This represents the portion of the transparent photosensitive resin layer (60). By performing the subsequent development processing, as shown in FIG. 2, the first photo spacer (Ps-1) having a high height and a large width and the second photo having a height lower than the first photo spacer and a small width. The spacer (Ps-2) and the orientation control protrusion (Mv) having a smaller height and a smaller width than the second photo spacer are obtained at the same time.

The exposure method based on this proximity exposure is, for example, a method in which the photosensitive resin layer (60) on the glass substrate and the film surface (51) of the photomask are brought into close contact with each other to provide exposure. (60) When foreign matter is present on the surface, the foreign matter is reattached to the film surface (51) of the photomask, and when a large amount of glass substrate is exposed as it is, a pattern caused by the presence of the foreign matter is obtained. This is a method for avoiding the formation of a large amount of defective color filters. Therefore, the proximity exposure gap is usually about 50 μm to 70 μm.

  In the present invention, when exposure is performed through a photomask on which patterns corresponding to the alignment control protrusion (Mv), the first photospacer (Ps-1), and the second photospacer (Ps-2) are formed. , The gap (G) of the proximity exposure is made larger than usual, and the diffraction of the irradiated light becomes remarkable, and the alignment control protrusion (Mv), the first photospacer (Ps-1), and the second photospacer (Ps) -2) is intended to be formed simultaneously.

  In addition, as the photosensitive resin used for forming the photosensitive resin layer, the positive photosensitive resin is generally more susceptible to the diffraction effect of the irradiated light than the negative photosensitive resin. As the photosensitive resin, a positive photosensitive resin is preferably used.

  In the present invention, it is necessary that the formed photospacer has a restoring force that is deformed when a load is applied and restored when the load is removed. The restoration rate is preferably 60% or more. In order to secure the restoration rate of 60% or more, it is desirable that the horizontal cross section of the photo spacer is 15 μm to 40 μm square.

  By making the gap (G) of the proximity exposure larger than usual, a 25 μm or more corner of the pattern forming the first photo spacer on the photomask, and a 15 to 25 μm square of the pattern forming the second photo spacer, A difference of 9 μm to 12 μm of the pattern forming the alignment control protrusion appears as a difference in height, and the photospacer has physical properties (restoration rate) as a photospacer.

It is sectional drawing explaining the proximity exposure in one Example of the manufacturing method of the color filter for liquid crystal display devices by this invention. It is explanatory drawing of the orientation control protrusion, the 1st photo spacer, and the 2nd photo spacer which were obtained after the image development process. It is a fragmentary sectional view of the color filter for liquid crystal display devices in which two types of photo spacers were formed. It is the top view which showed typically an example of the color filter used for a liquid crystal display device. FIG. 5 is a cross-sectional view taken along line X-X ′ of the color filter illustrated in FIG. 4. It is a fragmentary sectional view of the color filter for liquid crystal display devices in which the photo spacer was formed. It is explanatory drawing of the principle of MVA-LCD. (A) is a top view which expands and shows one pixel of an example of the color filter used for MVA-LCD. FIG. 4B is an enlarged cross-sectional view illustrating one pixel of an example of a color filter used in an MVA-LCD. (A) is a top view which expands and shows one pixel of another example. (B) is sectional drawing which expands and shows one pixel of another example.

Explanation of symbols

4, 7, 8, 9 ... color filter 20 ... TFT side substrate 21 ... liquid crystal molecules 22a, 22b, 23, 83, 93, Mv ... alignment control protrusions 40, 50 ... glass substrate 41 ... Black matrix 41A ... Black matrix matrix part 41B ... Black matrix frame part 42 ... Colored pixel 43 ... Transparent conductive film 44 ... Photo spacer 51 ... Photo mask Film surface 60 ... photosensitive resin layer 80 ... MVA-LCD
G ... proximity exposure gap H2 ... stripe-shaped alignment control protrusion height H3 ... circular alignment control protrusion height H4 ... first photo spacer height H5 ... second Height H6 of the photo spacer ... Height L of the alignment control projection ... Exposure light PM ... Photo mask Ps-1 ... First photo spacer Ps-2 ... Second photo spacer S4 ... The light shielding portion S5 corresponding to the first photo spacer. The light shielding portion S6 corresponding to the second photo spacer. The light shielding portion W2 corresponding to the alignment control protrusion. The width W3 of the stripe-shaped alignment control protrusion.・ Width W4 of the circular alignment control protrusion ... Width W5 of the first photo spacer ... Width W6 of the second photo spacer ... Width of the alignment control protrusion

Claims (4)

In a method for producing a color filter for a liquid crystal display device in which a black matrix, a colored pixel, a transparent conductive film, an alignment control protrusion, a first photo spacer, and a second photo spacer are formed on a transparent substrate,
1) A photosensitive resin layer is formed by applying a photosensitive resin on the transparent substrate on which the black matrix, the colored pixels, and the transparent conductive film are formed.
2) When performing exposure through the photomask on which the pattern corresponding to the orientation control protrusion, the first photospacer, and the second photospacer having a height lower than the first photospacer is formed, the photosensitive resin Proximity exposure with a gap between the upper surface of the layer and the film surface of the photomask is performed,
A method for producing a color filter for a liquid crystal display device, characterized in that development processing is performed to simultaneously form an alignment control protrusion, a first photo spacer, and a second photo spacer having a height lower than the first photo spacer.   The method for producing a color filter for a liquid crystal display device according to claim 1, wherein the photosensitive resin is a positive photosensitive resin.   The gap of the proximity exposure is 70 μm when the horizontal cross section of the first photo spacer is 25 μm × 25 μm or more, the horizontal cross section of the second photo spacer is 15 μm to 25 μm square, and the width of the alignment control protrusion is 9 μm to 12 μm. The method for producing a color filter for a liquid crystal display device according to claim 1 or 2, wherein the color filter is -300 m.   A color filter for a liquid crystal display device manufactured using the method for manufacturing a color filter for a liquid crystal display device according to any one of claims 1 to 3.

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