JP2001305531A - Liquid crystal display device and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device and a method for manufacturing the device in which deterioration in the display characteristics due to the irregularity of the cell gap can be suppressed even when a reflection film having a scattering structure (rugged pattern) is formed on a substrate. SOLUTION: The liquid crystal display device has a liquid crystal held between a front substrate and a back substrate facing each other. The surface of the back substrate opposite to the liquid crystal is formed into a rugged pattern, and a protective film is formed on the surface having the rugged pattern, and further, a protective film to cover the reflection film is formed. Since the diffusing reflection face is formed on the opposite surface of the back substrate to the liquid crystal, a flattening film is not required on the opposite face to the liquid crystal. Therefore, the structure is advantageous for that an irregular cell gap due to a flattening film can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal display device and a method for manufacturing the same.

[0002]

2. Description of the Related Art As shown in FIG. 6, a reflection type liquid crystal display device, which has been widely used, has a front substrate 6 and a rear substrate 7 which face each other via a sealing material (not shown).
And a liquid crystal 8 sandwiched between the two substrates. The front substrate 6 has a plurality of transparent electrodes 61 extending in a predetermined direction and an alignment film 62 serving as an organic thin film, while the back substrate 7 has a plurality of transparent electrodes 61 extending in a direction intersecting the transparent electrodes 61. Reflecting electrode 71, planarizing film 72 and alignment film 7
And 3. As shown in FIG. 6, each of the reflective electrodes 71 is formed in a thin film shape on a large number of fine irregularities formed on the inner surface of the rear substrate 7, and the surface has irregularities reflecting these irregularities. Will be formed. With this configuration, the light incident from the front substrate 6 side and reflected by the reflective electrode 71 is appropriately scattered and emitted from the front substrate 6 side. Can be avoided. Further, the surface of the rear substrate 7 on which the reflective electrodes 71 are formed is covered with a flattening film 72 for flattening irregularities on the surface of the reflective electrodes 71.

[0003]

However, since the flattening film 72 is formed of a resin material or the like, its hardness is relatively low, and therefore, the granular film 72 sandwiched between the two substrates together with the liquid crystal 8 is used. Spacer 9 is a flattening film 7
2 may be sunk into the surface.
In the vicinity of the portion where the spacer 9 has been entrapped, the cell gap becomes narrower than in other portions, and as a result, there is a limit in achieving the uniform cell gap. Was.

[0004] Further, in the thin planarizing film 72, irregularities reflecting the irregularities on the rear substrate 7 are formed on the surface thereof. Therefore, the flattening film 72 is thin enough to completely planarize the irregularities on the rear substrate 7. It is necessary to form the oxide film 72. However, when such a thick flattening film 72 is formed and subjected to heat treatment (for example, baking of the alignment film 73 covering the back substrate 7), the heat treatment is performed due to a difference in the thermal expansion coefficient of the flattening film 72. Since a wavefront-like unevenness is formed on the surface, it is difficult to make the cell gap uniform after all.

As described above, it is difficult to maintain a uniform cell gap in a liquid crystal display device having unevenness for forming a scattering structure on a reflective film. As a result, uniform display characteristics are obtained over the entire surface of the substrate. There were limits to achieving this. On the other hand, in addition to the liquid crystal display device having the reflection electrode having the functions of the reflection plate and the electrode as described above, the reflection plate is formed on the inner surface of the back substrate, and the surface of the flattening film covering the reflection plate is formed on the surface. A reflection type liquid crystal display device having a configuration in which a transparent electrode is formed separately from a reflection plate has also been proposed.
The same problem as described above may occur in such a liquid crystal display device.

The present invention has been made in view of the circumstances described above, and even when a reflective film having a scattering structure (unevenness) is formed on a substrate, display characteristics caused by non-uniform cell gaps. It is an object of the present invention to provide a liquid crystal display device capable of suppressing deterioration of a liquid crystal display and a method for manufacturing the same.

[0007]

According to the present invention, there is provided a liquid crystal display device comprising a pair of substrates facing each other, wherein a liquid crystal is sandwiched between the pair of substrates. Irregularities are formed on the side of the one substrate opposite to the liquid crystal, a reflective film is formed on the side of the one substrate where the irregularities are formed, and on the one substrate side of the reflective film, An object of the present invention is to provide a liquid crystal display device in which unevenness corresponding to the unevenness formed on the substrate is formed.

According to such a liquid crystal display device, since the scattering reflection surface is formed on the one substrate opposite to the liquid crystal, it is not necessary to form a flattening film on the surface facing the liquid crystal. For this reason, there is an advantage that a situation where the cell gap becomes non-uniform due to the flattening film can be prevented.

Here, in the above invention, a configuration may be adopted in which a layer made of an organic material or an inorganic material is provided on the side opposite to the one substrate with respect to the reflection film. With this configuration, the reflective film can be protected by the layer, and the unevenness that can be formed by reflecting the unevenness of the substrate can be flattened on the opposite side of the reflective film from the one substrate. There is an advantage that you can.

According to an experiment conducted by the inventor of the present invention, in the unevenness of the one substrate, the distance from the top of each projection to the top of another projection adjacent to the projection is one.
It was confirmed that when the height of the unevenness was 0.1 μm or more and 500 μm or less and the height of the unevenness was 0.1 μm or more and 10 μm or less, good scattering characteristics in the reflective film were obtained.
Therefore, it is desirable that the irregularities on the rear substrate have such a shape.

It is also conceivable that the reflective film in the above invention is formed of a reflective metal, for example, a single metal of aluminum or silver, or an alloy containing aluminum or silver as a main component. Furthermore, it is conceivable that the protective film is formed of, for example, silicon dioxide, an inorganic material containing silicon, or an acrylic, epoxy, or polyimide organic material.

Further, as a result of an experiment conducted by the inventor of the present invention, when the thickness of the one substrate is set to 0.4 mm or less, the parallax of a display image caused by an optical path difference caused by this thickness is observed. It was confirmed that it could be suppressed to the extent that it could not be recognized by the eyes of the elderly. Therefore, it is desirable that the thickness of the one substrate be 0.4 mm or less.

The present invention also relates to a method of manufacturing a liquid crystal display device in which a liquid crystal is sandwiched between a pair of substrates facing each other, wherein a step of forming irregularities on one of the pair of substrates is provided. And a step of forming a reflective film on the side of the one substrate on which the irregularities are formed, so that the side opposite to the side on which the irregularities of the pair of substrates are formed faces the other substrate,
Bonding the pair of substrates to each other.

According to the liquid crystal display device obtained by carrying out such a manufacturing method, the unevenness is formed on the side of the one substrate opposite to the liquid crystal, and the unevenness is formed on the side of the one substrate facing the liquid crystal. There is no need to form irregularities. Therefore,
Since a flattening film for flattening irregularities is not required on the surface facing the liquid crystal, it is possible to avoid a situation in which the cell gap becomes non-uniform due to the flattening film, and thus, the uniformity over the front surface of the substrate. Display characteristics can be obtained.

In the above invention, it is preferable that the method further includes a step of forming a layer made of an organic material or an inorganic material on a side opposite to the one substrate with respect to the reflection film. By providing such a layer, the reflective film can be protected, and the unevenness that can be formed on the one substrate side of the reflective film by reflecting the unevenness of the substrate can be flattened. There is an advantage.

In each of the steps of the above-described manufacturing method, in the step of forming irregularities on one substrate, the irregularities may be formed by using a chemical etching method. Further, in this case, a hydrofluoric acid-based etchant can be used. In the reflection film forming step, the reflection film may be formed by using a sputtering method, an evaporation method, or an ion plating method. Further, in the protective film forming step, a spin coating method,
The protective film is preferably formed by a printing method, a bar coating method, a dipping method, a discharge coating method, or a sol-gel method.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. Such an embodiment shows one aspect of the present invention, and does not limit the present invention, and can be arbitrarily changed within the scope of the present invention.

A: First Embodiment A-1: Configuration of First Embodiment First, a first embodiment in which the present invention is applied to a passive-matrix reflective liquid crystal display device will be described. FIG.
1 is a cross-sectional view illustrating a configuration of the liquid crystal display device 1. In addition, in FIG. 1 and each of the drawings shown below, in order to make each layer and each member a size that can be recognized on the drawing,
The scale is different for each layer and each member.

As shown in FIG. 1, this liquid crystal display 1
In this method, a front substrate 10 and a rear substrate 20 each having electrodes and the like formed thereon are bonded together via a sealing material 30, and a gap (cell gap) between the two substrates is made uniform in a region surrounded by the both substrates and the sealing material 30. A large number of granular spacers 40 and liquid crystals 50 for sealing are sealed. In addition, among the components shown in FIG. 1, the back substrate 20 corresponds to “one substrate” in the claims, and the front substrate 10 corresponds to “the other substrate” in the claims.

The front substrate 10 is a plate-like member made of glass, quartz, plastic, or the like. A plurality of strip-shaped transparent electrodes 101 are provided on the inner surface (the liquid crystal 50 side) of the front substrate 10.
Are formed extending in the left-right direction in FIG.
Each transparent electrode 101 is made of, for example, ITO which is a transparent conductive material.
(Indium Tin Oxide) or the like. further,
The surface of the front substrate 10 on which the plurality of transparent electrodes 101 are formed (the surface on the liquid crystal 50 side) is covered with an alignment film 102. The alignment film 102 is an organic thin film such as polyimide, and has been subjected to a uniaxial alignment process (for example, a rubbing process) for defining the alignment direction of the liquid crystal 50 when no voltage is applied. Note that a polarizing plate, a retardation plate, or the like for polarizing incident light in a predetermined direction is attached to the outside of the front substrate 10 (the side opposite to the liquid crystal 50), but it has a direct relationship with the present invention. Therefore, description and illustration are omitted.

On the other hand, the back substrate 20 is a plate-like member such as glass, quartz, and plastic. A plurality of strip-shaped transparent electrodes 201 and an alignment film 202 are formed on the inner surface (the liquid crystal 50 side) of the back substrate 20, similarly to the front substrate 10. However, the transparent electrode 201 is formed to extend in a direction intersecting the direction in which the transparent electrode 101 extends. Under such a configuration, the liquid crystal 50 sandwiched between the front substrate 10 and the rear substrate 20 has the transparent electrodes 1
When a voltage is applied between the transparent electrode 201 and each of the transparent electrodes 201, the alignment direction changes. That is, the region where each transparent electrode 101 and each transparent electrode 201 intersect functions as a pixel.

Here, a plurality of fine irregularities are formed on the surface of the back substrate 20 opposite to the liquid crystal 50. The reflection film 21 is formed of a metal having a reflectivity (for example, aluminum) on the surface on which the unevenness is formed. The incident light from the front substrate 10 is reflected on the surface of the reflective film 21 (the surface in contact with the rear substrate 20) and emitted to the front substrate 10 side. Specifically, external light such as sunlight or indoor lighting enters from the front substrate 10 side, and a polarizing plate (not shown) → the front substrate 10 → the transparent electrode 101 → the alignment film 102 → the liquid crystal 50 → the alignment film 202 → transparent. Electrode 201 →
The light reaches the reflection film 21 through a path of the rear substrate 20 → the reflection film 21, is reflected on the surface of the reflection film 20, and is emitted from the front substrate 10 side by following the above path in reverse.

Here, since the reflection film 21 is formed in the region of the surface of the rear substrate 20 where the irregularities are formed, the reflection film 21 is formed.
Irregularities along the irregularities are formed on the surface on the side of the rear substrate 20. As a result, the incident light from the front substrate 10 is emitted from the front substrate 10 after being appropriately scattered by the unevenness of the reflection film 21, so that the background is reflected in an image visually recognized by an observer, It is possible to avoid a situation in which light from illumination is reflected.

The protective film 22 is a film that covers the surface of the rear substrate 20 on which the reflective film 21 is formed, and is formed of, for example, a polyimide resin. This protective film 22
In addition to protecting the rear substrate 20 and the reflection film 21, the surface plays a role of flattening the irregularities formed on the surface of the reflection film 21.

A-2: Method of Manufacturing Liquid Crystal Display 1 Next, a method of manufacturing the liquid crystal display 1 will be described with reference to FIG. In FIG. 2, (a1) to (a7) show the manufacturing steps for the rear substrate 20, and (b1) to (b3) show the manufacturing steps for the front substrate 10.

First, a plate-like member 20a to be the back substrate 20
(For example, a glass plate having a thickness of about 0.2 mm) is prepared (FIG. 2A1), and one surface of the plate member 20a is roughened with an abrasive. Thereafter, the polished surface is subjected to wet etching using an aqueous solution of hydrofluoric acid or the like as an etchant, so that the back substrate 20 having irregularities formed on the surface can be formed (FIG. 2A).
2)). In addition, by appropriately selecting an abrasive used for polishing, an etching time, and the like, the shape of the unevenness formed on the surface of the rear substrate 20 (eg, pitch and inclination angle of the unevenness).
Can have a desired shape. For example, 0.1
having a depth of about μm to 10 μm (the distance between the most depressed portion of the concave portion and the top of the convex portion), and having a depth of 1 μm to 500 μm
It is conceivable to form one having a pitch of the order (the distance from the top of each projection to the top of another projection adjacent to the projection).

Next, a reflective film 21 made of aluminum, for example, having a thickness of 200 nm is formed on the surface of the
2 to 500 nm (FIG. 2A
3)). The reflection film 21 is formed by, for example, a sputtering method.
It can be formed using an electron beam evaporation method, an ion plating method, or the like. As described above, unevenness along the unevenness formed on the rear substrate 20 is formed on the surface of the reflective film 21 that is in contact with the rear substrate 20.

Subsequently, a resin material (for example, a polyimide resin) is applied to a thickness of, for example, about 0.05 mm to 0.1 mm on the surface of the rear substrate 20 on which the reflection film 21 is formed, and then fired to protect the resin material. A film 22 is formed (see FIG.
4)). In applying the resin material, for example, a spin coating method, a discharge coating method, a printing method, a bar coating method,
Various methods such as a dipping method and a sol-gel method can be used.

Next, an ITO thin film is formed by sputtering or the like on the surface of the back substrate 20 on which the unevenness is not formed. Then, a plurality of strip-shaped transparent electrodes 201 are formed by performing etching, photolithography, and the like on the thin film (FIG. 2 (a5)). Further, the back substrate 20 on which these transparent electrodes 201 are formed
After applying and baking a polyimide or the like on the surface of the substrate to form an alignment film, the alignment film is subjected to a uniaxial alignment process (for example, a rubbing process) according to a twist angle of a liquid crystal to be used (FIG. 2 (a6)). .

Subsequently, a seal material 30 having a shape surrounding the edge of the rear substrate 20 is printed on the rear substrate 20 (FIG. 2 (a7)). The sealing member 30 is provided with a liquid crystal sealing port (not shown) for sealing the liquid crystal 50 later.

On the other hand, on the surface of the front substrate 10 such as a glass substrate, a plurality of transparent electrodes 101 and an alignment film 102 are formed by the same steps as those for the transparent electrode 201 and the alignment film 202 on the rear substrate 20 (see FIG. 1). FIG. 2 (b1) and (b2)). Further, on the surface of the front substrate 10 on which these parts are formed, a large number of spacers 40 made of particles such as glass and plastic are scattered.

Next, the rear substrate 20 and the front substrate 10 obtained by the above-described steps are joined via the sealing material 30 such that the surfaces on which the electrodes are formed face each other. After this,
After the liquid crystal 50 is injected from the liquid crystal filling port provided in the sealing material 30, the liquid crystal filling port is sealed with a sealing material (adhesive or the like) to complete the liquid crystal display device 1 (FIG. 2).
(C)).

The above is the method for manufacturing the liquid crystal display device 1 according to the present embodiment.

According to the embodiment described above, the unevenness for scattering the reflected light is formed not on the surface of the rear substrate 20 on the liquid crystal 50 side but on the surface on the opposite side of the liquid crystal 50. Therefore, unlike the related art, it is not necessary to form a flattening film on the surface of the rear substrate facing the liquid crystal. Therefore, it is possible to avoid a situation where the cell gap becomes non-uniform due to the flattening film, and thus it is possible to obtain uniform display characteristics over the entire surface of the substrate.

Specifically, according to the present embodiment, it is not necessary to provide a flattening film on the inner surface of the rear substrate, so that the cell gap is non-uniform due to irregularities that are likely to occur on the surface of the flattening film. Never be. Further, the rear substrate 20 is
For example, since it is formed of a glass plate or the like, the surface in contact with the liquid crystal 50 has a sufficient hardness as compared with the resin film. Therefore, it is possible to solve a problem that can occur in the above-described conventional technique, such as the spacer 40 being sunk into the rear substrate 20. Therefore, even with such an operation, the cell gap can be made uniform.

Furthermore, since irregularities of any shape can be formed without considering the non-uniformity of the cell gap caused by the irregularities, for example, any shape (depth etc.) that can exhibit good scattering characteristics can be obtained. The effect that the scattering structure of (1) can be created is also obtained.

B: Second Embodiment B-1: Configuration of Second Embodiment Next, a second embodiment in which the present invention is applied to an active matrix type reflection type liquid crystal display device will be described. FIG. 3 is a cross-sectional view schematically illustrating a configuration of the liquid crystal display device 2 according to the present embodiment. Note that, among the units shown in FIG. 3, the same reference numerals are given to the same units as those of the liquid crystal display device 1 shown in FIG. As shown in FIG. 1, the liquid crystal display device 2 includes a front substrate 10 and a rear substrate 20 opposed to each other with a sealing material 30 interposed therebetween, and a spacer 40 and a liquid crystal 50 sandwiched between the two substrates.

A counter electrode 103 is formed on the entire surface (on the liquid crystal 50 side) of the front substrate 10. The counter electrode 103 is made of ITO which is a transparent conductive material.
And the like. The surface of the front substrate 10 on which the counter electrode 103 is formed is covered with the alignment film 102.

The outer surface of the rear substrate 20 (the side opposite to the liquid crystal 50) in the present embodiment has the same irregularities as the rear substrate 20 in the above embodiment.
A reflection film 21 is formed on the surface of the rear substrate 20 having such irregularities, and a protective film 22 that covers the reflection film 21 is formed. A plurality of scanning lines (not shown) extending in a predetermined direction and a direction intersecting the scanning lines are provided on the surface of the rear substrate 20 on the liquid crystal 50 side (that is, the surface on which the unevenness is not formed). A plurality of data lines (not shown) extending to the switching element 203 and the pixel electrode 20 provided corresponding to each intersection of the scanning line and the data line.
4 and a color filter 205 are formed. Further, the surface of the back substrate 20 on which these parts are formed is covered with an alignment film 202. Here, each switching element 203 is a means for performing switching control of a voltage applied to the pixel electrode 204, and is, for example, a thin film transistor (TFT). Each pixel electrode 204 is formed of a transparent conductive material such as ITO. The color filter 205 is a thin film that covers the surface of each pixel electrode 204, and is formed of a resin material colored R (red), G (green), or B (blue) with a dye or a pigment.

B-2: Method of Manufacturing Liquid Crystal Display 2 Next, a method of manufacturing the liquid crystal display 2 according to this embodiment will be described with reference to FIG. First, in the same process as the process described in the first embodiment (FIGS. 2A1 to 2A4), irregularities are formed on one surface of the plate member 20a to form the rear substrate 20, 4 (a1) and (a2)), the reflection film 2 covering the surface of the rear substrate 20
1 and the protective film 22 are formed (FIGS. 4A3 and 4A4). Next, a plurality of scanning lines, a plurality of data lines, and a plurality of switching elements 203 (for example, a thin film transistor) are formed on the surface of the thus obtained rear substrate 20 where no irregularities are formed. These components can be formed by using various known methods, and a description thereof will be omitted. Subsequently, ITO is formed on the surface of the back substrate 20 on which the plurality of scanning lines and data lines and the plurality of switching elements 203 are formed by sputtering or the like.
Is formed. Then, the thin film is subjected to etching, photolithography, or the like to form a plurality of pixel electrodes 204 arranged in a matrix corresponding to the intersection of the scanning line and the data line. Further, a resin film colored in any one of R, G, and B is formed on the surface of the rear substrate 20 on which these components are formed, and a part of the resin film is subjected to etching, photolithography, and the like. Pixel electrode 2
A color filter 205 that covers the area 04 is formed. Another two-color filter 2 covering some other pixel electrodes 204
05 can be formed by the same process (FIG. 4A5).

Next, an alignment film 202 is formed on the surface of the back substrate 20 on which the pixel electrodes 204 and the like are formed by the same process as that shown in the first embodiment (FIG. 4A6). A seal material 30 having a shape surrounding the edge of the rear substrate 20 is printed (FIG. 4A7).

On the other hand, a counter electrode 103 made of ITO or the like is formed on one surface of the front substrate 10 such as a glass substrate by using a sputtering method or the like (FIG. 4 (b1)). Then, an alignment film 102 covering the counter electrode 103 is formed (FIG. 4B2), and a large number of granular spacers 40 are scattered (FIG. 4B3).

Next, the back substrate 20 and the front substrate 10 obtained by the above-described steps are joined via a sealing material 30 so that the surfaces on which electrodes and the like are formed face each other.
0 to complete the liquid crystal display device 2 (FIG. 4).
(C)). According to this embodiment, the same effect as that of the first embodiment can be obtained. Furthermore, in the present embodiment, since irregularities are formed on the outer surface of the rear substrate 20,
The surface on which the switching elements and the like are formed can have sufficient flatness. Here, when irregularities for scattering the reflected light are formed on the inner surface of the rear substrate 20, it is necessary to form the switching elements on the surface on which the irregularities are formed. It is difficult to make it uniform. In addition, it is conceivable to selectively etch a region where the switching element is formed in the region where the unevenness is formed to flatten the region, but in such a case, the manufacturing process of the liquid crystal display device may be performed. Is complicated. On the other hand, according to the present embodiment, since a plurality of switching elements 203 can be formed on the surface of the rear substrate 20 having a sufficient flatness, the characteristics of each switching element can be made uniform without increasing the number of manufacturing steps. There is an advantage that can be made.

C: Modifications While one embodiment of the present invention has been described above, the above embodiment is merely an example, and various modifications may be made to the above embodiment without departing from the spirit of the present invention. be able to. For example, the following modifications can be considered.

<Modification 1> In each of the above embodiments,
In order to protect and flatten the reflection film 21, the protection film 22 is formed on the surface of the reflection film 21 opposite to the rear substrate 20, but the protection film 22 is not necessarily provided. . That is, for example, when there is no need to protect or planarize the reflective film 21, the protective film 2
2 may not be provided. In this case, an effect is obtained that the thickness of the liquid crystal display device can be reduced by the amount corresponding to the protective film 22 as compared with the above embodiments.

<Modification 2> If the thickness of the rear substrate 20 is equal to or greater than a predetermined thickness, an image visually recognized by an observer due to an optical path difference caused by this thickness causes parallax (floating characters). May occur. Here, FIG.
FIG. 2 is an enlarged cross-sectional view showing the configurations of a reflection film 21 and a protective film 22. According to the experiment by the inventor of the present invention, the thickness of the back substrate 20 at the most concave portion of the concave portion of the region where the unevenness of the rear substrate 20 is formed (that is, FIG.
When the thickness T) is 0.4 mm or less, it was confirmed that the parallax caused by the thickness of the rear substrate 20 was suppressed to a level that the observer could not recognize. Therefore,
It is desirable that the thickness of the back substrate 20 in the recess is 0.4 mm or less.

Further, as a result of an experiment conducted by the inventor, the distance between the top of one protrusion and the top of the protrusion closest to the protrusion among the protrusions and recesses formed on the rear substrate 20 (ie, 5, that is, the pitch of the unevenness is 1 μm or more and 500 μm or less, and the height of the unevenness (that is, the height H shown in FIG. 5) is 0.1 μm or more and 10 μm or less.
m or less, the reflective film 2 formed on the unevenness
It was confirmed that No. 1 provided particularly good scattering characteristics. Therefore, it is desirable to form irregularities on the rear substrate 20 so as to satisfy the above conditions. The shape of the unevenness should be controlled by appropriately selecting the etching conditions (etching time or type of etchant) applied to the plate member 20a shown in FIG. 2 (a1) or FIG. 4 (a1). Can be. Further, as a result of an experiment, it was confirmed that good reflection characteristics were obtained when the thickness of the reflection film 21 was 10 nm or more and 500 nm or less. Therefore, it is desirable that the film thickness of the reflection film 21 be within this range.

In each of the above-described embodiments, the back substrate 20 having irregularities is formed by roughening the surface of the plate member 20a and then performing etching, but the surface of the plate member 20a is formed on the surface of the plate member 20a. The method for forming the unevenness is not limited to this. For example, a resin film is formed for each of a large number of fine regions on one surface of the plate-shaped member 20a, and a part (corner) of each resin film is melted by performing a heat treatment, so that the surface is formed on the surface. Irregularities may be formed.

Further, in each of the above embodiments, the back substrate 20 having the unevenness formed on one entire surface is exemplified, but a partial area of the surface (for example, an area where an image is displayed).
The unevenness may be formed only on the surface. Similarly, in each of the above embodiments, the reflection film 21 covering the entire area of the rear substrate 20 where the unevenness is formed is exemplified. May cover only a part (for example, an area where an image is displayed).

<Modification 3> In each of the above embodiments,
Although the case where the reflective film 21 is formed of aluminum has been described as an example, the reflective film 21 may be formed of a material having reflectivity.
A metal such as silver, or a metal containing aluminum or silver as a main component can also be used. Further, in each of the above embodiments, the case where the protective film 22 is formed of a polyimide-based resin is exemplified.
For example, various materials such as silicon dioxide (SiO ₂ ) or a silicon-based inorganic material, or an acrylic or epoxy-based organic material can be used.

<Modification 4> In the second embodiment, the switching element 203 is formed on the rear substrate 20. However, the switching element 203 may be formed on the front substrate 10 as a matter of course. Also in this case, the method described in each of the above embodiments can be used as a method for forming the irregularities on the substrate.

[0052]

As described above, since the rear substrate of the liquid crystal display device according to the present invention has a structure in which irregularities are formed on the side opposite to the liquid crystal side, the rear substrate has a flat surface on the liquid crystal side. There is no need to form an oxide film. Therefore, it is possible to prevent a non-uniform cell gap, which may be caused by the flattening film, and to obtain a uniform display characteristic over the entire surface of the substrate.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically illustrating a configuration of a liquid crystal display device according to a first embodiment of the invention.

FIG. 2 is a view schematically showing a manufacturing process of the liquid crystal display device.

FIG. 3 is a cross-sectional view schematically illustrating a configuration of a liquid crystal display device according to a second embodiment of the invention.

FIG. 4 is a view schematically showing a manufacturing process of the liquid crystal display device.

FIG. 5 is an enlarged cross-sectional view illustrating a configuration of a rear substrate of the liquid crystal display device according to the present invention.

FIG. 6 is a cross-sectional view illustrating the configuration of a conventional reflective liquid crystal display device.

[Explanation of symbols]

 Liquid crystal display device 10 Front substrate 101 Transparent electrode 102 Alignment film 103 Counter electrode 20 Back substrate 21 Reflective film 22 Protective film 201 Transparent electrode 202 ... Alignment film 203 ... Switching element 204 ... Pixel electrode 205 ... Color filter 30 ... Seal material 40 ... Spacer 50 ... Liquid crystal

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2H089 KA15 LA07 NA24 NA25 PA06 QA12 QA14 RA05 TA01 TA04 TA09 TA17 2H090 JA04 JA13 JA16 JB02 JB03 JD01 MB02 2H091 FA16Y FB07 FB08 FC02 FC26 FD06 FD15 FD23 GA08 GA13 A09 LA09 BA03 BA43 CA19 CA24 EA04 EA05 EA07 EB02 EC03 ED03 ED11 GB10 5G435 AA00 BB12 EE33 FF03 KK05

Claims (6)

[Claims] 1. A liquid crystal display device in which liquid crystal is sandwiched between a pair of substrates facing each other, wherein irregularities are formed on one of the pair of substrates on a side opposite to the liquid crystal, A reflection film is formed on a side of the one substrate on which the irregularities are formed, and irregularities corresponding to irregularities formed on the substrate are formed on the one substrate side of the reflective film. A liquid crystal display device characterized by the above-mentioned. 2. A liquid crystal display device comprising a layer made of an organic material or an inorganic material on a side opposite to the one substrate with respect to the reflection film. 3. The unevenness of the one substrate, wherein the distance from the top of each protrusion to the top of another protrusion adjacent to the protrusion is 1 μm or more and 500 μm or less, and the height of the unevenness 3. The liquid crystal display device according to claim 1, wherein a is 0.1 μm or more and 10 μm or less. 4. 4. The liquid crystal display device according to claim 1, wherein said one substrate has a thickness of 0.4 mm or less. 5. A method for manufacturing a liquid crystal display device comprising a liquid crystal sandwiched between a pair of substrates facing each other, the method comprising: forming unevenness on one of the pair of substrates; Forming a reflective film on the side of the substrate where the irregularities are formed, and joining the pair of substrates so that the side opposite to the side where the irregularities of the pair of substrates are formed faces the other substrate And a method for manufacturing a liquid crystal display device. 6. The liquid crystal display device according to claim 5, further comprising a step of forming a layer made of an organic material or an inorganic material on a side of the reflection film opposite to the one substrate. Production method.