JP2007225646A - Liquid crystal display device and method for manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transflective or reflective liquid crystal display device where the occurrence of iridescent interference fringes (moire) caused by periodicity of a reflection irregular pattern in a reflection section is suppressed. <P>SOLUTION: In the liquid crystal display device which has a first substrate and a second substrate, having the reflection sections which have reflection layers arranged on surfaces of resin layers with protrusions and recesses formed thereon, placed opposite to each other via a liquid crystal layer, the protrusions and recesses are formed by overlapping those of a first pattern arranged by repeating them in a predetermined direction and those of a second pattern arranged by repeating them in the predetermined direction and different from the first pattern with each other, wherein the first and second patterns contain a plurality of protrusions and recesses in respective pattern regions, and a pattern length in the predetermined direction in the first pattern and that in the second pattern are different from each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a liquid crystal display device having a reflective portion that reflects external light and a method for manufacturing the same, and more particularly to a transflective type that suppresses the occurrence of rainbow-colored buffer stripes (moire) due to the periodicity of the reflective unevenness pattern of the reflective portion. The present invention also relates to a reflective liquid crystal display device and a method for manufacturing the same.

In recent years, the application of liquid crystal display devices has rapidly spread not only in information communication equipment but also in general electric equipment. Since the liquid crystal display device does not emit light by itself, a transmissive liquid crystal display device having a backlight is often used. However, because the power consumption of the backlight is large,
In particular, for a portable type, a reflective liquid crystal display device that does not require a backlight is used to reduce power consumption.

In addition, since this reflection type liquid crystal display device uses external light as a light source, it is difficult to see a display image in a dark room or the like. Therefore, in recent years, transflective liquid crystal display devices having both transmissive and reflective properties have been developed. This transflective liquid crystal display device has a transmissive portion having a transparent electrode and a reflective portion having a reflective electrode in one pixel region, and in a dark place, the backlight is turned on to transmit the transmissive portion. The image is displayed using the light, and in a bright place, the backlight is not turned on and the image is displayed using the external light in the reflection portion. Thereby, it is not always necessary to turn on the backlight, and the power consumption can be greatly reduced.

Here, an example of a conventional reflective liquid crystal display device will be described with reference to FIGS. In addition,
FIG. 8 is a plan view of one pixel showing the color filter substrate of the reflection type liquid crystal display device of the prior art as seen through, and FIG. 9 is a cross-sectional view taken along line AA of FIG. 8 including the color filter substrate.

The reflection type liquid crystal display device 10A of this conventional example includes an array substrate 12 and a color filter substrate 13 that face each other with a liquid crystal layer 11 interposed therebetween. The array substrate 12 is formed on a transparent glass substrate 14 so that a plurality of scanning lines 15 made of a metal such as aluminum or molybdenum are parallel to each other at an equal interval, and at an approximate center between adjacent scanning lines 15. Auxiliary capacitance electrode 1
6 are formed in parallel to each other, and a gate electrode G of the TFT is extended from the scanning line 15.

Further, a gate insulating film 17 made of silicon nitride, silicon oxide, or the like is laminated over the entire surface of the array substrate 12 so as to cover the scanning lines 15, the auxiliary capacitance electrodes 16, and the gate electrodes G. A semiconductor layer 18 made of amorphous silicon, polycrystalline silicon, or the like is formed through the insulating film 17, and a plurality of signal lines 19 made of a metal such as aluminum or molybdenum are formed on the gate insulating film 17 with the scanning lines 15. The source electrode S of the TFT is extended from the signal line 19 and is in contact with the semiconductor layer 18. Further, a drain electrode D, which is the same material as the signal line 19 and the source electrode S and is formed simultaneously, is provided on the gate insulating film 17, and the drain electrode D
Is also in contact with the semiconductor layer 18.

Here, a region surrounded by the scanning lines 15 and the signal lines 19 corresponds to one pixel. The gate electrode G, the gate insulating film 17, the semiconductor layer 18, the source electrode S, and the drain electrode D constitute a TFT serving as a switching element, and this TFT is formed in each pixel. In this case, the auxiliary capacitance of each pixel is formed by the drain electrode D and the auxiliary capacitance electrode 16.

A protective insulating film 20 made of an inorganic insulating material such as silicon nitride is laminated over the entire surface of the array substrate 12 so as to cover the signal lines 19, the TFTs, and the gate insulating film 17,
An interlayer film 21 made of an organic insulating film is laminated on the entire surface of the array substrate 12 on the protective insulating film 20, and a large number of reflective uneven portions 22 are formed on the surface of the interlayer film 21 in each pixel portion. In FIG. 8, the reflection uneven portion 22 is omitted. A contact hole 23 is formed in the protective insulating film 20 and the interlayer film 21 at a position corresponding to the drain electrode D of the TFT.
Are formed on the surface of the contact hole 23 and the interlayer film 21 independently for each pixel, for example, a reflective electrode 24 made of silver or aluminum and a transparent electrode made of ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide). 25, and an alignment film (not shown) is laminated on the surface of the transparent electrode 25 so as to cover all the pixels.

The color filter substrate 13 is a color filter made of, for example, red (R), green (G), or blue (B) corresponding to each pixel provided on the array substrate 12 on the transparent glass substrate 26. The layer 27 is provided in a stripe shape, and a common electrode and an alignment film (both not shown) are laminated on the surface of the color filter layer 27. The reflective liquid crystal display device 10A is formed by enclosing the liquid crystal layer 11 between the array substrate 12 and the color filter substrate 13.

In the reflective liquid crystal display device 10A having such a configuration, a large number of reflective uneven portions 22 are formed on the surface of the interlayer film 21 of each pixel portion. The reflective uneven portions 22 are formed on this surface. The reflective electrode 24 is used to diffusely reflect external light to improve the visibility of the display image. However, the reflection uneven portion 22 is manufactured by exposing using a mask having a predetermined pattern when the interlayer film 21 is formed. However, a mask in which the arrangement position of the reflection uneven portion 22 is random throughout the mask. Since it is difficult to fabricate, a pattern for fabricating the reflective uneven portion 22 for one pixel to several pixels is fabricated, and a predetermined mask is fabricated by repeatedly using this pattern. Therefore, in the conventional reflective liquid crystal display device 10A, since the periodicity of the structure of the reflective concavo-convex portion 22 exists, there is a problem that the reflected light causes an interference phenomenon based on this periodicity and moire occurs. . Such a problem also occurs in a transflective liquid crystal display device having a transmissive portion in each pixel.

In a liquid crystal display device having such a reflective part, theoretically, if the arrangement position of the reflective concavo-convex part 22 is different in all pixels so that there is no repeated pattern in the reflective concavo-convex part 22, the above-mentioned Clearly, moire due to interference can be avoided. However, since not only the number of target pixels is very large but also the number of reflection uneven portions 22 formed in one pixel, the arrangement positions of the reflection uneven portions 22 of all the pixels are made random. Considering the difficulty in manufacturing the mask, it is substantially difficult to implement.

In order to prevent the occurrence of moire based on the periodicity of the structure of such a reflective concavo-convex portion, the following Patent Document 1 discloses an invention of a reflective liquid crystal display device employing a specific concavo-convex pattern structure. Here, a reflective liquid crystal display device 10B disclosed in the following Patent Document 1 will be described with reference to FIGS. 10 is a cross-sectional view of one pixel at the boundary of the display area of the reflective liquid crystal display device, and FIGS. 11A to 11D show the top of the basic figure during the convex pattern manufacturing process shown in FIG. It is a figure which shows the change of the thickness of a side part, FIG. 11A is a top view of one basic figure part, FIG. 11B-FIG. 11D is the BB sectional drawing of FIG. 10 and 11, the same reference numerals are given to the same components as those of the reflective liquid crystal display device 10 shown in FIGS. 10 and 9, and a detailed description thereof is omitted.

An array substrate 12 of the reflective liquid crystal display device 10B includes a plurality of scanning lines 15, a TFT gate electrode G, an auxiliary capacitance electrode (not shown), a gate insulating film 17, on a transparent glass substrate 14.
The semiconductor layer 18, the signal line 19, the source electrode S and the drain electrode D of the TFT are formed, and the surface of the semiconductor layer 18 is covered with the protective insulating film 20. However, the structure of the reflective uneven portion of the interlayer film is different.

That is, in the reflective liquid crystal display device 10B, a photosensitive organic resin is applied on the protective insulating film 20, and then exposed and developed, and a plurality of lines are formed by a linear mask for forming a convex pattern. after forming a convex pattern 21 ₃ consisting Itadakiten portion 21 ₁ and the side portion 21 ₂ which of Jo shape, causes the corner portion by performing the heat sintering of the organic resin rounded. This convex pattern 2
1 _3, as shown in FIGS. 11A and 11B, the basic shape is formed such that the triangles. Next, an interlayer film made of a photosensitive organic resin so as to cover the convex pattern 21 ₃ is applied, as shown in FIG. 11C, after the surface has a smooth irregular shape, is subjected to exposure and development processes Contacts opening the hole 23, then, an interlayer film 21 ₄ performs heat sintering. next,
In correspondence with the formation position of the reflection electrode 20, after forming an aluminum thin film covering the interlayer film 21 ₄ with the contact hole 23, exposure and development processes, as shown in FIG. 10, the reflective electrode as the reflective pixel electrode 24 is formed. Thus, in the reflective type liquid crystal display device 10B as disclosed in Patent Document 1, the basic diagram form a reflecting uneven portion serving as a triangle with convex patterns 21 ₃ and the interlayer film 21 _4. In addition, in Patent Document 1 described below, a rhombus, an ellipse, or the like can be adopted as a basic figure in addition to a triangle.
JP 2003-75831 A (claims, [0005] to [0008], [0024] to [0029], FIG. 1, FIG. 2, FIG. 4)

According to the liquid crystal display device 10B disclosed in the above-mentioned Patent Document 1, the shape of the reflective concavo-convex portion is such that the basic shape is a meter shape such as a triangle, a rhombus, or an ellipse.
Light incident from a light source at an angle of 30 degrees with the normal direction of the display surface can be efficiently reflected in the normal direction of the display surface, and interference caused by light path differences can be suppressed. Thus, an excellent effect is obtained that an anisotropic reflection type liquid crystal display device that can be obtained is obtained. However, due to the reflective irregularity portion formed, to form a convex pattern 21 ₃ consisting of the first to the linear shape mask for projecting the pattern formation of a plurality of linear shape Itadakiten portion 21 ₁ and the side portion 21 ₂ which to further basic shapes with an interlayer film 21 ₄ later forms the reflective irregularity portion serving as a triangle, steps increases, moreover exists a problem that the mask special pattern of linear shape masks required Yes.

The present invention has been made in view of the above-described problems of the prior art, and its purpose is not to require a mask with a special pattern as described above, and the reflective irregularities are formed in a predetermined repeated arrangement. However, it has a reflection part such as a reflective liquid crystal display device or a transflective liquid crystal display device in which the generation of moire due to the periodicity of the reflective uneven pattern of the reflective part is suppressed and the display image quality of the reflective part is good An object of the present invention is to provide a liquid crystal display device and a manufacturing method thereof.

In order to achieve the above object, in the liquid crystal display device of the present invention, a first substrate and a second substrate having a reflective portion in which a reflective layer is provided on the surface of a resin layer having irregularities are arranged to face each other via a liquid crystal layer. In the liquid crystal display device
The unevenness is an unevenness formed by superimposing unevenness of a first pattern repeatedly provided in a predetermined direction and unevenness of a second pattern different from the first pattern provided repeatedly in the predetermined direction. The first pattern and the second pattern include a plurality of concave portions and convex portions in the area of each pattern, and the pattern length in the predetermined direction is different between the first pattern and the second pattern. It is characterized by that.

In the liquid crystal display device of the present invention, in the above liquid crystal display device, the size of the concave portion and the convex portion included in the first pattern is different from the size of the concave portion and the convex portion included in the second pattern. It is characterized by that.

Moreover, the liquid crystal display device of the present invention is the above-described liquid crystal display device, wherein the depth and height of the recesses and protrusions included in the first pattern, the depth of the recesses and protrusions included in the second pattern, and The height is different.

The liquid crystal display device of the present invention is characterized in that, in the liquid crystal display device described above, the reflective film also serves as a pixel electrode provided for each pixel.

The liquid crystal display device of the present invention is the liquid crystal display device according to any one of the above, wherein the first substrate includes a concavo-convex portion and a transmissive portion not provided with a reflective layer for each pixel. And

Furthermore, in order to achieve the above object, a method for manufacturing a liquid crystal display device of the present invention includes:
On one main surface side of the first substrate, an uneven portion forming region of a first pattern provided repeatedly in a predetermined direction, and a pattern different from the first pattern provided repeatedly in the predetermined direction, Forming a resin layer having a concavo-convex portion on the surface so as to be a pattern in which the concavo-convex formation region of the second pattern different in pattern length in the predetermined direction from the first pattern;
A step of forming a reflective layer on the surface of the resin layer having irregularities after the step of forming the resin layer having irregularities;
Bonding the first substrate and the second substrate so as to face each other;
It is characterized by providing.

Further, the method for manufacturing a liquid crystal display device of the present invention is the above-described method for manufacturing a liquid crystal display device,
The resin layer having unevenness on the surface is manufactured by using a mask having a pattern obtained by synthesizing the unevenness forming area of the first pattern and the unevenness forming area of the second pattern.

Further, the method for manufacturing a liquid crystal display device of the present invention is the above-described method for manufacturing a liquid crystal display device,
The resin layer having unevenness on the surface is repeatedly provided in a predetermined direction using a multi-tone mask or a halftone mask provided with the unevenness forming region of the first pattern, and then the unevenness forming region of the second pattern. The first pattern is repeatedly provided in the predetermined direction so as to overlap the region provided repeatedly in the predetermined direction.

The method for manufacturing a liquid crystal display device of the present invention is the method for manufacturing a liquid crystal display device according to any one of the above, wherein the size of the concave portion and the convex portion included in the first pattern and the concave portion and the convex portion included in the second pattern. It is characterized in that the sizes of the parts are different.

In addition, the method for manufacturing a liquid crystal display device according to the present invention includes any one of the above-described methods for manufacturing a liquid crystal display device, the depth and height of the recesses and protrusions included in the first pattern, and the second pattern. The depth and height of the concave and convex portions are different.

Further, the method for manufacturing a liquid crystal display device of the present invention is the above-described method for manufacturing a liquid crystal display device,
The reflective layer is formed of a conductive material for each pixel and functions as a pixel electrode.

In addition, the method for manufacturing a liquid crystal display device according to the present invention is the method for manufacturing a liquid crystal display device according to any one of the above, wherein a transmissive portion that is not provided with an uneven portion and a reflective layer is provided for each pixel on the surface of the resin layer. It is characterized by having prepared.

By providing the above-described configuration, the present invention has the following excellent effects. That is, according to the liquid crystal display device of the present invention, the reflection uneven portion has a second pattern different from the first pattern repeatedly provided in the same direction as the unevenness of the first pattern provided repeatedly in the predetermined direction. The first pattern and the second pattern include a plurality of concave portions and convex portions in the area of each pattern, and the pattern length in a predetermined direction is composed of the concave and convex portions formed by overlapping the concave and convex portions. However, since the first pattern and the second pattern are different, the reflection uneven portion is a long-period random pattern. Therefore, according to the liquid crystal display device of the present invention, the interference of the scattered reflected light based on the periodicity of the reflective concavo-convex portion is reduced, so that the occurrence of moire is reduced and a liquid crystal display device with good display image quality can be obtained.

Further, according to the liquid crystal display device of the present invention, since the unevenness of the first pattern and the unevenness of the second pattern are different, even if the unevenness of each pattern is a simple shape, the combined unevenness Is a very complicated and substantially random shape, and therefore a liquid crystal display device with less display of moire and good display image quality can be obtained.

Further, according to the liquid crystal display device of the present invention, since the depth of the concave portion of the first pattern and the height of the convex portion and the depth of the concave portion of the second pattern and the height of the convex portion are different, the unevenness of each pattern Even if the shape is simple, the combined irregularities are not only two-dimensionally random, but also three-dimensional and random, resulting in less moiré. A liquid crystal display device with good image quality can be obtained.

In addition, according to the liquid crystal display device of the present invention, it is not necessary to provide a separate pixel electrode, so that a liquid crystal display device that can achieve the effects of the present invention while having a simple structure can be obtained.

In addition, according to the liquid crystal display device of the present invention, since each pixel electrode is provided with a transmissive portion, a transflective liquid crystal display device that can achieve the effects of the above invention can be obtained.

Furthermore, according to the method for manufacturing a liquid crystal display device of the present invention, the liquid crystal display device according to the present invention can be easily manufactured.

In addition, according to the method of manufacturing a liquid crystal display device of the present invention, a mask in which the first pattern and the second pattern are easily synthesized can be obtained by overlapping the first pattern and the second pattern. By using a mask in which the pattern and the second pattern are combined, exposure and
It is possible to form the reflective irregularities having a predetermined long-period structure without increasing the number of development steps.

In addition, according to the method for manufacturing the liquid crystal display device of the present invention, the first pattern and the second pattern are formed by forming the second pattern reflection uneven portion after forming the first pattern reflection uneven portion forming region. Without producing a mask in which the patterns are combined, it is possible to obtain a reflective uneven portion having a predetermined long-period structure in which the first pattern and the second pattern are combined.

Hereinafter, a specific example of a method for manufacturing a display device according to the present invention will be described in detail with reference to the drawings. However, the embodiments described below are described by taking as an example a method of manufacturing a liquid crystal display device having a reflective portion for embodying the technical idea of the present invention, and the present invention is intended to be specified to this. However, the present invention can be equally applied to various modifications without departing from the technical idea shown in the claims. The reflective liquid crystal display devices manufactured in the following Example 1 and Example 2 are different from the conventional reflective liquid crystal display device 10A shown in FIGS. Only the arrangement pattern is different, and the other configurations are substantially the same. Therefore, in the following description, the same components as those of the reflection type liquid crystal display device 10A of the conventional example will be described with reference to the reference numerals shown in FIGS. However, the illustration of the reflective liquid crystal display devices of the first and second embodiments is omitted.

The pattern thru | or mask used when manufacturing the reflection type liquid crystal display device which concerns on Example 1 is demonstrated using FIGS. 1 is a diagram showing a first pattern used in Example 1, FIG. 2 is a diagram showing a second pattern, and FIG. 3 is a composite of the first pattern shown in FIG. 1 and the second pattern shown in FIG. FIG. 4 is a diagram showing a pattern of a mask used in Example 1 obtained by using the pattern shown in FIG.

The first pattern 31 shown in FIG. 1 is composed of, for example, 3 × 3 = 9 sub-patterns, and these nine sub-patterns are all composed of fully transmissive layers produced by repeating a pattern 31a surrounded by a thick frame. It is a binary mask. A plurality of (for example, eight) circular patterns 31b in the pattern 31a surrounded by a thick frame all have the same size, and the size is a small diameter of 4 to 10 μm. Therefore, all nine sub-patterns are the same pattern, and the circular patterns in each sub-pattern all have the same diameter. The pattern length (cycle) in the horizontal axis x direction of the pattern 31a surrounded by the thick frame is α, and the pattern length in the vertical axis y direction is α ′.

The second pattern 32 shown in FIG. 2 is composed of, for example, square 2 × 2 = 4 sub-patterns, and these four sub-patterns are all produced by repeating the pattern 32a surrounded by a thick frame. It is a binary mask composed of a transparent layer. A plurality of (for example, six) circular patterns 32b in the pattern 32a surrounded by a thick frame all have the same size, which is larger than that of the first pattern shown in FIG. A diameter larger than 10 μm is adopted. Therefore, all four sub-patterns are the same pattern,
All the circular patterns in each sub-pattern have the same diameter. The pattern length in the horizontal axis x direction of the pattern 32a surrounded by the thick frame is β, and the pattern length in the vertical axis y direction is β ′.

Here, the pattern length β in the x direction of the second pattern 32a has a relationship of β = α × 3/2 and the pattern length β ′ = α ′ × 3/2 in the y direction. That is, the first pattern 31 and the second pattern
The pattern 32 is a square of substantially the same size (when α = α ′ and β = β ′) or a rectangle (when α ≠ α ′ and β ≠ β ′). However, the relationship between β and α and the relationship between β ′ and α ′ are originally arbitrary as long as the relationship β> α and β ′> α ′ is satisfied, but the first pattern of the same size is repeatedly used by repeatedly using subpatterns. For the convenience of manufacturing 31 thru | or 2nd pattern 32, p and q are set to p.
When a positive integer satisfying the relationship of <q is satisfied, it is desirable to satisfy the relationship of β × p = α × q and β ′ × p = α ′ × g.

When the first pattern 31 shown in FIG. 1 and the second pattern 32 shown in FIG. 2 thus obtained are overlapped to obtain a composite layer, the pattern 33 shown in FIG. 3 is obtained. FIG.
Among the patterns 33 shown in FIG. 2, the small-diameter circular pattern corresponds to the circular pattern 31b in FIG. 1, and the large-diameter circular pattern corresponds to the circular pattern 32b in FIG. The pattern 33 shown in FIG. 3 includes a portion X where the large-diameter circular pattern 32b and the small-diameter circular pattern 31b overlap, and a portion where the large-diameter circular pattern 32b includes the small-diameter circular pattern 31b. Y
Exists.

When a binary mask is produced using the pattern 33 shown in FIG. 3 thus obtained,
In FIG. 3, a portion X where the large-diameter circular pattern 32b and the small-diameter circular pattern 31b overlap and a portion Y where the small-diameter circular pattern 31b is included in the large-diameter circular pattern 32b are the surrounding patterns. Example 1 having the same pattern as shown in FIG.
The mask 30 used in the above is obtained. In order to manufacture the liquid crystal display device of Example 1 using this mask 30, a photosensitive resin is applied on the protective insulating film 20 to a predetermined thickness, and exposure processing is repeatedly performed in a predetermined direction using the mask 30. Then, a convex portion is produced by developing, and then heat baking treatment is performed so that the corners are rounded. Then, the interlayer having the reflective irregularities 22 (see FIG. 9) having the pattern as shown in FIG. A membrane 21 is obtained. The depth of the concave portion (the height of the convex portion) of the reflective uneven portion 22 is the same height for both the portion corresponding to the small-diameter circular pattern 31b and the portion corresponding to the large-diameter circular pattern 32b.

Thereafter, like the conventional example, after the contact hole 23 is formed, a reflective electrode 24 made of aluminum or the like is formed in the surface of the reflective uneven portion 22 and in the contact hole 23, and ITO is formed on the surface of the reflective electrode 24 as necessary. The array substrate 12 used in the liquid crystal display device of Example 1 is obtained by forming the transparent electrode 25 made of the like. Next, in the same manner as in the case of the conventional example, the liquid crystal layer 11 is sealed between both substrates so as to face the color filter substrate 13, whereby the reflective liquid crystal display device of Example 1 is obtained.

The mask 30 used in the first embodiment having the pattern as shown in FIG. 4 has three times the pattern lengths α and α ′ of the pattern 31a shown in FIG. Since twice the pattern lengths β and β ′ of the pattern 32a shown are synthesized (superposed), the repetition period in the horizontal axis x direction is 3α = 2β, and the repetition period in the vertical axis y direction is 3α. Since '= 2β' and a long-period random pattern is obtained, it is possible to reduce the interference of scattered reflection caused by the periodicity of the pattern. Therefore, in the reflective liquid crystal display device obtained by the manufacturing method of Example 1, the occurrence of moire is dramatically reduced.

In the first embodiment, a mask in which two patterns are combined is prepared so that the exposure / development process is completed once. However, the heights of the obtained reflection uneven portions 22 are all the same. Therefore, in the second embodiment, the height of the reflection uneven portion 22 can be provided. The mask used when manufacturing the reflective liquid crystal display device according to Example 1 of Example 2 will be described with reference to FIGS. 5 is a diagram showing a first pattern mask used in Example 2, FIG. 6 is a diagram showing a second pattern mask, and FIG. 7 is a plan view of a reflective uneven portion obtained in Example 2. is there.

The mask 41 of the first pattern shown in FIG. 5 is composed of, for example, 2 × 2 = 4 sub-patterns, and these four sub-patterns all have a gradation transmission produced by repeating a pattern 41a surrounded by a thick frame. It consists of a halftone mask (or multi-tone mask) consisting of layers. Then, a plurality of (for example, eight) circular patterns 41b in the pattern 41a surrounded by a thick frame.
All have the same size, and the size is a small diameter of 4 to 10 μm. Accordingly, the four sub-patterns are all the same pattern, and the circular patterns in each sub-pattern all have the same diameter. Pattern 41a surrounded by this thick frame
The pattern length (cycle) in the horizontal axis x direction is γ, and the pattern length in the vertical axis y direction is γ ′.

Further, the mask 42 of the second pattern shown in FIG. 6 is composed of, for example, square 2 × 2 = 4 sub-patterns, and these four sub-patterns are all produced by repeating the pattern 42a surrounded by a thick frame. It is a binary mask composed of all transparent layers. A plurality of (for example, eight) circular patterns 42b in the pattern 42a surrounded by a thick frame all have the same size, which is larger than that of the first pattern shown in FIG. Large, 10μm
The diameter exceeding is adopted. Accordingly, the four sub-patterns are all the same pattern, and the circular patterns in each sub-pattern all have the same diameter. The pattern length in the horizontal axis x direction of the pattern 42a surrounded by the thick frame is δ, and the pattern length in the vertical axis y direction is δ ′.

Here, the pattern length δ in the vertical axis x direction and the pattern length δ ′ in the horizontal axis y direction of the second pattern 42a are the pattern length γ in the vertical axis x direction and the pattern length γ ′ in the horizontal axis y direction of the first pattern 41a.
Both are larger, that is, δ> γ and δ ′> γ ′. Therefore, the size of the second pattern 42a is larger than the size of the first pattern 41a. However, the relationship between γ and δ and the relationship between γ ′ and δ ′ are originally arbitrary as long as the relationship of δ> γ and δ ′> γ ′ is satisfied.
It is desirable that γ and δ and γ ′ and δ ′ are close to each other for the convenience of manufacturing the reflection uneven portion 22 by repeatedly using the first pattern mask and the second pattern mask.

Using the halftone mask 41 having the first pattern as shown in FIG. 5 and the binary mask having the second pattern as shown in FIG.
Is manufactured as follows. That is, a photosensitive resin is applied to the protective insulating film 20 to a predetermined thickness, and first, exposure processing is repeatedly performed in a predetermined direction using the halftone mask 41 having the first pattern. Then, the small-diameter circular pattern 41b portion of the first pattern is not exposed at all, but the other portions are exposed to about half. Thereafter, a binary mask 42 having a second pattern is used to repeatedly perform exposure processing in a predetermined direction, and further develop to produce a convex portion, and then heat baking processing to round the corner portion. Then, FIG.
Thus, the interlayer film 21 having the reflection uneven portion 22 having the pattern as shown in FIG.

Thereafter, as in the case of the conventional example or the first embodiment, after forming the contact hole 23, a reflective electrode 24 made of aluminum or the like is formed on the surface of the reflective uneven portion 22 and in the contact hole 23, and reflected as necessary. By forming the transparent electrode 25 made of ITO or the like on the surface of the electrode 24, the array substrate 12 used in the liquid crystal display device of Example 1 is obtained. Then
Similarly to the case of the conventional example, the liquid crystal layer 11 is opposed to the color filter substrate 13 between the substrates.
The reflective liquid crystal display device of Example 2 is obtained.

The reflection uneven portion 22 in the reflective liquid crystal display device of Example 2 having the pattern as shown in FIG. 7 is twice the pattern length γ or γ ′ of the first pattern 41a formed of the gradation transmission layer in a predetermined region. The pattern length δ or δ ′ of the second pattern 42a comprising the minute and total transmission layers
However, since each pattern has a different periodicity, it has a long-period random pattern. Moreover, the height of the convex part of the obtained reflective uneven part 22 is a part corresponding to the small-diameter circular pattern 41b even if it is an independent circular pattern or partially overlaps with another circular pattern. 45
The portion 46 corresponding to the large-diameter circular pattern 42b has a lower height than that, and the randomness of the pattern is very large. Therefore, the reflection type liquid crystal display device obtained by the manufacturing method of Example 2 can reduce the interference of scattering reflection caused by the periodicity of the pattern and drastically reduce the occurrence of moire.

In addition, although Example 1 and Example 2 demonstrated the example of the reflective liquid crystal display device, the above-mentioned reflective uneven | corrugated | grooved part 22 is the reflective unevenness | corrugation in the reflective part of the transflective liquid crystal display device which has a transmissive part in a part of each pixel. It is clear that it can be applied as a part. In this case, since it is only necessary to obtain an interlayer film having a flat surface without providing a reflection uneven portion in the transmissive portion, a circular shape is formed at a position corresponding to the transmissive portion of each pixel electrode in each pattern shown in FIGS. What is necessary is just to make it not provide a pattern.

It is a figure which shows the 1st pattern used in Example 1. FIG. It is a figure which shows the 2nd pattern used in Example 1. FIG. It is a figure which shows the pattern which synthesize | combined the 1st pattern shown in FIG. 1, and the 2nd pattern shown in FIG. It is a figure which shows the pattern of the mask used in Example 1 obtained using the pattern shown in FIG. 6 is a diagram showing a mask of a first pattern used in Example 2. FIG. FIG. 10 is a diagram illustrating a second pattern mask used in the second embodiment. 6 is a plan view of a reflective uneven portion obtained in Example 2. FIG. It is the top view for 1 pixel which sees and represented the color filter substrate of the reflection type liquid crystal display device of the prior art example. It is AA sectional drawing of FIG. 8 containing a color filter board | substrate. It is sectional drawing for 1 pixel of the boundary part of the display area of the reflection type liquid crystal display device of another prior art example. 11A to 11D are views showing changes in the thickness of the top and sides of the basic figure during the convex pattern manufacturing process shown in FIG. 10, and FIG. 11A is a plan view of one basic figure part. 11B to 11D are cross-sectional views taken along line BB in FIG. 11A during the convex pattern manufacturing process.

Explanation of symbols

10A, 10B Reflective liquid crystal display device 11 Liquid crystal layer 12 Array substrate 13 Color filter substrate 14 Glass substrate 15 Scan line 16 Auxiliary capacitance electrode 17 Gate insulating film 18 Semiconductor layer 19 Signal line 20 Protective insulating film 21 Interlayer film 22 Reflective uneven part 23 Contact hole 24 Reflective electrode 25 Transparent electrode 30 Masks 31-33, 41-42 Patterns 31a, 32a, 41a, 42a Circular patterns 31b, 32b ′, 41b, 42b First pattern and second pattern

Claims (12)

In a liquid crystal display device in which a first substrate and a second substrate having a reflection portion in which a reflection layer is provided on the surface of a resin layer having irregularities are arranged to face each other via a liquid crystal layer,
The unevenness is an unevenness formed by superimposing unevenness of a first pattern repeatedly provided in a predetermined direction and unevenness of a second pattern different from the first pattern provided repeatedly in the predetermined direction. The first pattern and the second pattern include a plurality of concave portions and convex portions in the area of each pattern, and the pattern length in the predetermined direction is different between the first pattern and the second pattern. A liquid crystal display device characterized by the above. 2. The liquid crystal display device according to claim 1, wherein the size of the concave portion and the convex portion included in the first pattern is different from the size of the concave portion and the convex portion included in the second pattern. 2. The depth and height of the recesses and protrusions included in the first pattern are different from the depth and height of the recesses and protrusions included in the second pattern. Liquid crystal display device. The liquid crystal display device according to claim 1, wherein the reflective film also serves as a pixel electrode provided for each pixel. 5. The liquid crystal display device according to claim 1, wherein the first substrate includes a transmissive portion on which the uneven portion and the reflective layer are not provided for each pixel. On one main surface side of the first substrate, an uneven portion forming region of a first pattern provided repeatedly in a predetermined direction, and a pattern different from the first pattern provided repeatedly in the predetermined direction, Forming a resin layer having a concavo-convex portion on the surface so as to be a pattern in which the concavo-convex formation region of the second pattern different in pattern length in the predetermined direction from the first pattern;
A step of forming a reflective layer on the surface of the resin layer having irregularities after the step of forming the resin layer having irregularities;
Bonding the first substrate and the second substrate so as to face each other;
A method for manufacturing a liquid crystal display device, comprising: The resin layer having irregularities on the surface is manufactured using a mask having a pattern obtained by synthesizing the irregularity forming area of the first pattern and the irregularity forming area of the second pattern. The manufacturing method of the liquid crystal display device of description. The resin layer having unevenness on the surface is repeatedly provided in a predetermined direction using a multi-tone mask or a halftone mask provided with the unevenness forming region of the first pattern, and then the unevenness forming region of the second pattern. 7. The method of manufacturing a liquid crystal display device according to claim 6, wherein the first pattern is repeatedly provided in the predetermined direction by being overlapped with a region provided repeatedly in the predetermined direction using a binary mask comprising: . The size of the recessed part and the convex part included in the first pattern and the size of the concave part and the convex part included in the second pattern are made different from each other. A method for manufacturing a liquid crystal display device. The depths and heights of the recesses and protrusions included in the first pattern are different from the depths and heights of the recesses and protrusions included in the second pattern. A method for producing a liquid crystal display device according to any one of the above. The method of manufacturing a liquid crystal display device according to claim 6, wherein the reflective layer is formed of a conductive material for each pixel and functions as a pixel electrode. The liquid crystal display device according to any one of claims 6 to 11, wherein a surface of the resin layer is provided with a concavo-convex portion and a transmissive portion provided with no reflective layer for each pixel. Method.

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