JP2003043459A - Reflector and liquid crystal display - Google Patents

Abstract

(57) [Problem] To provide a high-performance reflector that easily controls the reflection characteristics of incident light and achieves required scattering characteristics. A plurality of strips (20) are arranged on a substrate (17), adjacent strips (20) are connected smoothly and continuously, and a light reflection layer (21) is formed on these strips (20) to use a reflector for display. P.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflective plate used for display such as a liquid crystal display device and a reflective or semi-transmissive liquid crystal display device.

[0002]

2. Description of the Related Art In recent years, liquid crystal display devices have been used not only for small or medium-sized portable information terminals and notebook computers, but also for large and high-definition monitors. Furthermore, the technology of a reflective liquid crystal display device that does not use a backlight has been developed, and is excellent in thinness, light weight, and low power consumption.

The reflection type liquid crystal display device is of a scattering reflection type in which an uneven light reflection layer is formed on the inner surface of a substrate arranged at the rear, but it is possible to effectively use ambient light by not using a backlight. Are used for.

Also, a transflective liquid crystal display device has been developed in which a transflective film is formed in place of the light reflection layer, a backlight is provided, and a reflective mode or a transmissive mode is selectively used. It can be said that this semi-transmissive liquid crystal display device is also a reflective liquid crystal display device when used in the reflection mode.

FIG. 18 shows such a scattering-reflection type liquid crystal display device 1. In the liquid crystal display device 1, a large number of substantially hemispherical convex portions 3 made of resin are arranged on the glass substrate 2 to form a convex array group, and a light reflecting layer 4 made of metal is formed on the convex array group. To form a color filter 5 on the light reflection layer 4, cover the color filter 5 with an overcoat layer 6, and arrange a plurality of transparent electrodes 7 made of ITO or the like on the overcoat layer 6 in a strip shape. Then, the alignment film 8 is further covered.

Further, a plurality of transparent electrodes 10 made of ITO or the like are arranged in a strip shape on the glass substrate 9, and the alignment film 11 is further formed.
To cover. Then, the two substrates 2 and 9 are arranged opposite to each other with the liquid crystal 12 interposed therebetween, and the liquid crystal 12 is filled in the region surrounded by the seal member 13, and the first retardation film 14 and the second retardation film 14 are provided on the outer surface of the glass substrate 9. Retardation film 15 and polarizing plate 16
And are sequentially formed.

In the liquid crystal display device 1 having the above structure, external light such as sunlight or fluorescent light passes through the polarizing plate 16, the first retardation film 14, the second retardation film 15, the glass substrate 9 and the like, The light reaches the light reflection layer 4 through the liquid crystal 12 and the color filter 5, and the reflected light is emitted.

However, according to this liquid crystal display device 1, in the convex array group formed on the glass substrate 2, since the convex portions 3 have a uniform hemispherical shape, the scattering reflection plate is optically equal or the like. However, unnecessary light scattering increases, and the light is also scattered in a direction different from the direction visually recognized by a person.

In order to solve this problem, a technique has been proposed in which a concave portion or a convex portion having an asymmetric axis is formed on the scattering reflection plate or the inclination angle distribution is made asymmetrical (Japanese Patent Laid-Open No. 10-177106). reference).

[0010]

However, according to the proposed reflector, although some degree of anisotropy of the scattering characteristics can be obtained, the user who uses the liquid crystal display device still has a problem with the liquid crystal panel. In the lateral direction, the scattering cannot be reduced, the brightness of the display screen has not reached a sufficient level, and further excellent visibility is required.

Further, in this reflecting plate, due to the manufacturing method, it is necessary to further process the extremely fine uneven shape more complicatedly, which makes the control of the scattering characteristics difficult and causes the manufacturing yield to decrease. Was becoming.

In addition, in recent years, in a reflective liquid crystal display device or a semi-transmissive liquid crystal display device used in a mobile terminal such as a mobile phone or an information terminal, the direction of the incident light is an important requirement for the user of the device. With the miniaturization of liquid crystal panels, legibility has become a major evaluation standard in the market.

However, it can be said that the liquid crystal display device for a mobile terminal, which often receives light from obliquely above the display screen, has not been sufficiently improved.

Therefore, an object of the present invention is to provide a high-performance reflector which easily controls the reflection characteristics of incident light and achieves the required scattering characteristics.

Another object of the present invention is to provide a low-cost reflector which has no manufacturing variations, has a high manufacturing yield, and has achieved a certain excellent quality.

Still another object of the present invention is to improve the efficiency of light incident on the display screen from above and below to increase the brightness, and also to obtain high performance by utilizing light incident from the lateral direction. It is to provide a reflector.

Still another object of the present invention is to improve the use performance by improving the reflection performance and the scattering performance with respect to the incident light by using the reflection plate of the present invention, and thereby the small liquid crystal such as a portable terminal. It is to provide a high-performance and low-cost liquid crystal display device suitable for a panel.

[0018]

The reflector of the present invention is used for display, and a plurality of linear strips are smoothly and continuously connected between adjacent strips on a substrate. And a light reflection layer is formed on these strips.

Another reflector of the present invention is characterized in that the cross-sectional shape of the strip is asymmetrically decentered with respect to the center line of the strip.

Still another reflection plate of the present invention is characterized in that a layer having a scattering property is formed on the light reflection layer.

In the liquid crystal display device of the present invention, a transparent electrode and an alignment film are formed on the reflection plate of the present invention to form one member, and this one member is aligned with the transparent electrode on the other substrate. The other member having the film formed thereon is bonded to the other member via a liquid crystal, and pixels are arranged in a matrix to be used for a reflection type or a semi-transmission type.

Furthermore, in the liquid crystal display device of the present invention, a transparent electrode and an alignment film are formed on a reflection plate to form one member, and this one member is provided on the other substrate with the transparent electrode and the alignment film. It is characterized in that it is used for a reflection type or a semi-transmission type by bonding the formed other member through a liquid crystal, arranging pixels in a matrix, and further providing a layer having a scattering property to the other member. To do.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the drawings. (Example 1) Manufacturing Method FIG 1 of a reflector represents the method for manufacturing a reflector of the present invention, (a) ~
(D) is each process.

Step (a): Transparent glass substrate 17 (thickness
0.55 mm) and the photosensitive resin 18 is applied thereon at a thickness of 1.5 ± 0.5 μm. Then, pre-bake at 105 ± 10 ° C. for 3 minutes.
As the photosensitive resin 18, for example, PC405G manufactured by JSR Corporation is used.

Step (b): Proximity exposure is performed by using a photomask 19 with ultraviolet light having a wavelength of 365 nm. FIG. 2 is an enlarged view of a main part of the photomask 19,
A light-shielding pattern S made of Cr or the like is formed on a transparent substrate such as a glass substrate.

According to the light shielding pattern S, a plurality of linear strips are arranged in a stripe pattern on the substrate.

Step (c): Next, development, exposure, and baking are performed to form the strip 20 on the glass substrate 17. That is, by utilizing the light wrapping around in the proximity exposure of the previous step, the corners of the pattern are removed and a smooth curved surface is obtained after development. The developer is PD5 made by JSR.
23AD (concentration 0.238 ± 0.1%), 50
Development was performed for ± 10 seconds (20 ° C.).

Then, the entire surface is exposed to remove the unreacted components of the photosensitive resin for decolorization, and then post-baking 220 ± 10 ° C. (15 minutes) is performed to cure the resin.

Step (d): Thereafter, Al, Al alloy (for example, AlCMg, AlTi,
AlNd), Ag alloy (for example, AgPd, AgPd
A metal light reflection layer or a dielectric mirror is formed of Cu, AgRuCu, AgCuAu) or the like. In this example, Ag
A Pd film having a thickness of 150 nm was formed by a sputtering method to form a light reflection layer 21.

Thus, the reflecting plate P of the present invention is obtained through the steps (a) to (d).

Structure of Reflector P The structure of the reflector P is shown in FIG. 9A is a plan view of the reflector, and FIG. 9B is a sectional view taken along the line AA in FIG.

As is apparent from FIG. 3 (b), the belt-like body 20 has no flat portion and has a smoothly continuous shape. Therefore, the light reflection layer 21 on the strip 20 is also smooth and continuous without any flat portion.

According to the reflection plate P thus obtained, the shape of the light reflection layer 21 on the strip 20 is a smooth continuous structure without a flat portion, so that the vertical direction in FIG. Light incident on the display screen can be scattered, which increases the incidence efficiency in a liquid crystal display device for a mobile terminal, which is often incident on the display screen from above. Was able to increase.

Moreover, as in the conventional case, the process of processing more complicatedly for the fine concavo-convex shape is not required, which increases the manufacturing yield, and as a result, the manufacturing cost is reduced.

As described above, according to the reflection plate P, as described above, the light reflection layer 21 is formed into a smooth continuous strip shape without a flat portion. It was possible to scatter incident light, which increased the light incident efficiency and brightness, but it was also possible to appropriately scatter incident light other than the incident light from above and below. Well, for that reason, the light reflection layer 21
It is preferable to form a layer having a scattering property on the above.

This point will be described below. Such a light scattering layer may be formed of, for example, a synthetic resin, and is formed by coating on the light reflecting layer 21.

As the scattering resin layer, a scattering translucent resin is applied, and the resin contains fine particles having a refractive index different from that of the medium as a scattering agent, and the scattering translucent light is used. The surface of the functional resin layer may be flattened so that backscattering due to unevenness does not occur.

For example, a scattering light-transmitting resin layer made of JSR is applied in a thickness of 5.0 ± 0.5 μm, and then 100 ±
It is advisable to pre-bake at a temperature of 10 ° C. for 3 minutes and then post-bake 220 ± 10 ° C. (15 minutes).

By forming the layer having the scattering property on the light reflection layer 21 as described above, incident light other than the incident light from the vertical direction of the display screen is also appropriately scattered, but in the liquid crystal display device. The above-mentioned scattering agent may be contained in the overcoat layer that is coated to enhance the smoothness, and thereby the function may be provided.

Alternatively, in the liquid crystal display device according to the fourth aspect, a layer having a scattering property may be formed outside the substrate of the other member. For example, Sumitomo Chemical's IDS
DS is 8μm on 80μm transparent substrate film made of TAC (triacetyl cellulose) without birefringence
Is applied with a scattering translucent resin, and the resin contains fine particles having a refractive index different from that of the medium as a scattering agent. Further, the surface of the light-scattering transparent resin layer is flattened so that backscattering due to unevenness does not occur.

Next, the evaluation of the optical characteristics of the reflector P will be described. As shown in FIG. 4, assuming a liquid crystal layer on the light reflection layer 21, a refractive index n made of acrylic synthetic resin or the like is used.
= About 1.5 resin 22 is applied, and glass substrate 23
A virtual liquid crystal panel 24 is configured by bonding the above. Then, the incident light is incident from a direction inclined by 15 ° from the vertical direction, and while rotating 360 °, the light receiving unit measures the reflectance in the vertical direction. To do.

Here, in order to determine the direction of incident light, FIG.
As shown in, the vertical direction is set in consideration of the direction in which the user of the liquid crystal display device is actually viewed, and the right side of the liquid crystal panel 24 is set to 0.
The upper part is defined as 90 °, the upper part as 180 °, and the lower part as 270 °.

As a reflector, a reflector P shown in FIG. 3 and a conventional reflector are prepared as shown in FIG. Since the strip-shaped body 20 of the reflection plate and the convex array group are continuously smooth, the shape and dimensions shown in the figure are indicated by the light-shielding pattern of the photomask used for manufacturing the same.

FIG. 3A shows a conventional reflector, which has the same structure as the scattering reflector provided in the liquid crystal display device 1 described above. The convex array group having a uniform hemispherical shape (circular diameter: 6 μm) is formed.

FIG. 3B shows a strip 20 (strip width: 6 μm) in the reflector P of the present invention, which is arranged in a stripe pattern on the display screen in the left-right direction, and the scattering resin is provided above the reflector P. A layer (Sumitomo Chemical IDS) was formed. With this, it was manufactured as Example 1.

Then, the reflection plate of the present invention of Example 1 and the reflection plate of the conventional example were prepared, and the reflection characteristics of these were measured by the optical characteristic evaluation method shown in FIG. 4. The results shown in FIG. 7 were obtained. was gotten.

As is apparent from the figure, in the conventional example, it does not depend on the incident direction and is constant from 0 ° to 360 °. On the other hand, in the first embodiment, the viewer does not need to use the screen in the lateral direction (horizontal direction). That is, when using a reflective / semi-transmissive panel,
Incident light is often incident from above compared to the lateral direction, so it is better to use the incident light from above more effectively, but there is almost no lateral scattering or reflection. It is set to zero and added to the upward scattering and reflection.

More specifically, as shown in FIG.
In Example 1, the strip-shaped strips 20 are 90 ° and 27.
They are arranged in the direction of 0 °, so that 90 °, 2
It can be seen that in the direction of 70 °, the light utilization efficiency is increased to about twice that in the conventional example.

Then, due to the effect of the scattering resin on the upper layer of the reflection plate, the maximum values are obtained at 90 ° and 270 °, and 0 ° and 180 °.
It can be seen that the value becomes gradually smaller as it approaches, and takes the minimum value at 0 ° and 180 °. Further, by controlling the degree of scattering of the scattering resin, it is possible to easily control the reflection characteristic in the incident direction. That is, if the scattering property of the scattering resin is low, the scattering property of the reflection plate in the linear direction cannot be expanded so much, and the scattering property with respect to the azimuth angle changes sharply around the linear direction. On the contrary, if the scattering property is high, the scattering property of the reflector in the linear direction is widened, and the scattering property with respect to the azimuth angle becomes gentle around the linear direction.

Thus, according to the reflection plate P of the present invention, the strip 20 can provide the desired directivity, and the reflection characteristics in the incident direction can be easily controlled. Also,
Since such directionality is determined by the design of the photomask, there is no manufacturing variation in the distribution, and a certain excellent quality can be achieved.

(Example 2) In the reflector shown in (Example 1), the cross-sectional shape of the band-shaped body is substantially symmetrical with respect to the center line of the band, but instead of this, such a band-shaped body is used. The cross-sectional shape of the body is asymmetrically eccentric to the centerline of the band.

The manufacturing method of this reflector is basically the same as the step shown in FIG. 1 described above, and each step will be described below with reference to FIG.

Step (a): A photosensitive resin 18 having a thickness of 1.5 ± 0.5 is formed on a transparent glass substrate 17 (having a thickness of 0.55 mm).
Apply at μm. Then, pre-bake at 105 ± 10 ° C. for 3 minutes. For this photosensitive resin 18, for example, PC405G made by JSR is used.

Step (b): A photomask 19 having a light shielding pattern different from that of the photomask shown in FIG.
Proximity exposure is performed with 65 nm ultraviolet light.

FIG. 8 is a plan view of the photomask 19, in which a light shielding pattern S made of Cr or the like is formed on a transparent substrate such as a glass substrate.

According to the light-shielding pattern S, a large number of strips are formed, and a large number of strip-shaped portions are provided on one side of each strip. This is shown in FIG.

FIG. 9A is an enlarged view of a main part of the light shielding pattern S, and FIG. 9B is a schematic plan view showing a strip-shaped body manufactured using the photomask of FIG. 9A. Further, (c) is a cross-sectional view taken along the section line--shown in FIG. 9 (b).

In the light-shielding pattern S shown in FIG. 9A, an innumerable strip shape is provided on one side of each linear strip, whereby the resolution on one side of the strip is provided. To reduce the resolution on the other side.

As can be seen from the sectional view in the section of FIG. 9 (c), the peak position of the unevenness is closer to the side.

It should be noted that such a light-shielding pattern is not limited to the strip shape, and may have various other shapes. For example, as shown in FIG. 10, (a) innumerable triangles may be arranged on one side of the strip-shaped portion, or (b) triangle-shaped bodies may be arranged in a strip-like shape to eliminate the strip-shaped portion.

The reason for this will be described below.

At the position of the photomask, since the space between the light shielding patterns is wide, the exposure is normally firm. At the position of, since the fine strip-shaped shapes are arranged at a narrow interval, the light is exposed more weakly due to the surrounding of the light. At the position of, the exposure is weaker due to the influence of the strip shape and the thick linear shape. At the position of, that is, near the center of the thick linear shape, the influence of the light wraparound is the least likely, and the exposure amount is the weakest.

Therefore, when the exposure doses are arranged in order, >>>, so that the residual film of the resist resin after development is <<<, and the order of the difference in height of the actual uneven sectional view is <b < It matches Ha <ni <e. And
By forming a myriad of strip-shaped shapes on the same upper side of the linear pattern, the area contributing to the reflection on the upper side increases, so that the reflectance on the upper side improves.

Step (c): Next, development, exposure and baking are performed to form the strip 20 on the glass substrate 17.

That is, by utilizing the light wraparound in the proximity exposure of the previous step, after the development, the corners of the pattern are removed and a smooth curved surface is obtained. For the developer, J
Development was performed for 50 ± 10 seconds (20 ° C.) using SR PD523AD (0.238 ± 0.1%).

Then, the entire surface is exposed to remove unreacted components of the photosensitive resin, decolorization is performed, and then post-baking 220 ± 10 ° C. (15 minutes) is performed to cure the resin.

Step (d): Thereafter, Al, Al alloy (for example, AlCMg, AlTi,
AlNd), Ag alloy (for example, AgPd, AgPd
Cu, AgRuCu, AgCuAu, AgCuAu) or the like is used to form a metal light reflection layer or a dielectric mirror.
In this example, an AgPd film having a thickness of 150 nm was formed by a sputtering method to form the light reflection layer 21. Thus, the reflection plate P of the present invention is obtained through the steps (a) to (d).

Next, the optical characteristics of the thus-prepared reflector P were evaluated by the method shown in FIGS. 4 and 5 in (Example 1).

As shown in FIG. 11, this reflection plate is a light-shielding pattern of each photomask in three types of reflection plates.

FIG. 11A shows the pattern of the reflector of the conventional example (a) shown in FIG. 6A, and FIG. 11B shows the pattern of the reflector of FIG. 6B. The strip-shaped body 20 in the reflector P of 1), and FIG. 11C shows the reflector P of this example.
It is the band-shaped body 20 in. In addition, the strip 20 of the reflection plate
Are continuous and smooth, the shapes and dimensions shown in the figure are shown in the light-shielding pattern of the photomask used for manufacturing them.

FIG. 11 (c) shows a strip 20 (strip width: 6 μm) in the reflector P of the present invention, the strip shape of which is changed in three ways, and a scattering resin layer (made by Sumitomo Chemical Co., Ltd.) is provided above the reflector. By forming IDS), Example 2-, Example 2-, and Example 2- were prepared as shown in FIG.

In Example 2-shown in FIG. 12 (a), a length of 3 μm and a width of 4 μ were applied to the band-shaped body of Example 1-.
A large number of strip-shaped portions of m are arranged at intervals of 4 μm.

In Example 2 shown in FIG. 9B, a large number of strip-shaped portions each having a length of 6 μm and a width of 4 μm are arranged at intervals of 4 μm on the strip-shaped body of Example 1-.

In Example 2-shown in FIG. 6C, a large number of strip-shaped portions each having a length of 9 μm and a width of 4 μm are arranged at intervals of 4 μm on the strip-shaped body of Example 1-.

As described above, Example 2 and Example 2
The three types of reflectors of the present invention of Example 2-, the above-mentioned Example 1 (Example 1), and the reflector of the conventional example (a) were produced, and these were evaluated as shown in FIG. When the reflection characteristics were measured, the results shown in FIGS. 13 to 15 were obtained.

FIG. 13 shows the measurement results of the reflector of Example 2-, and also shows the measurement results of the reflectors of Comparative Example (a) of the comparative example and Example 1.

FIG. 14 shows the measurement results of the reflector of Example 2-, and FIG. 15 shows the measurement results of the reflector of Example 2-.

As is clear from each of these figures, in the conventional example (a), 0 ° to 3 ° is independent of the incident direction.
It is constant over 60 °, whereas Example 1
(Example 1) and Example 2-, Example 2-, Example 2
It can be seen that in the three types of reflectors of the present invention, the stripe-shaped strips are arranged in the directions of 90 ° and 270 °, so that the light utilization efficiency is higher than that of the conventional example. Then, due to the effect of the scattering resin in the upper layer of the reflection plate, the maximum values are obtained at 90 ° and 270 °, and 0 ° and 180 °.
It can be seen that the value becomes gradually smaller as it approaches, and takes the minimum value at 0 ° and 180 °. Comparing (b) Example 1 with (c) Example 2, it was found that (b) Example 1 was 90 ± 90.
The reflectance in the range of 270 ± 90 ° is the same as that in the range of 270 ± 90 °, whereas (c) Example 2 is 270 ± 90 °.
The reflectance in the range of 90 ± 90 ° is larger than the range of. Further, the reflectance increases in the range of 90 ± 90 ° in the order of Example 2- <Example 2- <Example 2-. That is, the longer the length of the innumerable strip shape added to the linear shape of the reflector, the greater the reflectance in the range of 90 ± 90 °.

Thus, according to the reflector P of the present invention, depending on the shape to be added to the strip, the range of 0 ° to 180 ° and 1
It is possible to change the reflectance ratio between the two and the degree of the reflectance in the range of 80 ° to 360 °.

(Example 3) Each reflector P of (Example 1) and (Example 2)
The case of using a liquid crystal display device will be described.

FIG. 16 is a sectional view of the liquid crystal display device 54. The liquid crystal display device 54 is a reflection type for color display, and 55 is a glass substrate (0.55 mm) on the common side.
Thickness), 56 is a glass substrate (0.55 mm) on the segment side.
Thickness), a large number of strip-shaped convex portions 57, which are the strip-shaped bodies, are arranged on one main surface of the glass substrate 55 with a resin such as an acrylic resin material, and the silver alloy AgxPdy is arranged on the strip-shaped convex array group. The light reflection layer 58 having a thickness of 150 nm is covered with a film made of (x = 99.0 y = 1.0).

A resin color filter 59 made of an acrylic resin material or the like is formed on the light reflection layer 58. Further, an overcoat layer 60 including a scattering agent made of acrylic resin and a plurality of transparent electrodes 61 made of ITO arranged in parallel are formed. An alignment film 6 made of a polyimide resin rubbed in a certain direction on the transparent electrode 61.
Forming 2.

The above-mentioned one member is constructed as described above, but the other member is composed of the transparent electrodes 63 made of ITO arrayed in parallel on the glass substrate 56 and the polyimide resin rubbed in a certain direction. The alignment film 64 is sequentially formed. An insulating layer made of SiO ₂ may be interposed between the transparent electrode 63 and the alignment film 64.

Then, liquid crystal 6 such as STN is used for both substrates.
The seal member 66 is used to attach the two pieces. Further, a first retardation film 67 made of polycarbonate or the like, a second retardation film 68, and an iodine-based polarizing plate 69 are sequentially formed on the outside of the glass substrate 56.

In the reflection type liquid crystal display device 54 having the above-mentioned structure, incident light from external illumination such as sunlight or a fluorescent lamp passes through the glass substrate 56, the liquid crystal 65 and the color filter 59.
And the like, reach the light reflection layer 58, are reflected by the light reflection layer 58, and the reflected light is emitted.

The user of the reflection type liquid crystal display device 54 of the present embodiment normally uses the device while facing the device.
It is used with a vertical viewing angle, especially an upward viewing angle. Therefore, the strip-shaped portions of the strip-shaped convex portions 57, which are strip-shaped bodies, are arranged laterally with respect to the panel.

That is, in the reflection type liquid crystal display device 54 used in a portable information terminal or the like, the incident light is more often incident from above than in the lateral direction of the panel. By arranging the longitudinal direction of the convex portion 57) in the lateral direction of the panel, it is possible to effectively use incident light from above.

In addition, as shown in Examples 2-, 2-, and 2-, the cross-sectional shape of the strip portion of the strip is
When it is asymmetrically decentered with respect to the center line of the band, the position of the peak is set to the lower side of the reflective liquid crystal display device 54, and the incident light from above is used more effectively than in the first embodiment. ing.

The present inventor prepared the conventional example (a), Example 1 and Example 2 and evaluated the optical characteristics of the sample. The results shown in Table 1 were obtained.

For the evaluation measurement, a reflection type liquid crystal display device using each reflection plate was produced, and the device was placed near the center of an office in which 15 fluorescent lamps were arranged at intervals of 2 m to improve the display performance. I'm researching.

In a situation in which a general person uses a reflection type liquid crystal display device, the viewing angle of the person is shifted upward or downward, and the bright or dark state of the screen is checked by this.

The evaluation criteria are set in four ways: ◎, ○, △, ×, and ◎ marks are very bright, ○ marks are slightly bright, Δ marks are slightly dark, and X marks are remarkable. In the dark.

[0093]

[Table 1]

As is clear from this table, the reflection type liquid crystal display device equipped with the reflection plate of Example 1 was bright in the vertical direction. Further, in the reflection type liquid crystal display device equipped with the reflection plate of Example 2-, a reflection type liquid crystal display device having a brighter characteristic only in the upper direction was obtained.

(Example 4) Each reflector P of (Example 1) and (Example 2)
The case where the above is used in another liquid crystal display device will be described.

FIG. 17 is a sectional view of the liquid crystal display device 70. In the reflective liquid crystal display device 70 for color display, 71 is a glass substrate (0.55 mm) on the common side.
Thickness), 72 is a glass substrate (0.55 mm) on the segment side.
Thickness), a large number of strip-shaped convex portions 73, which are the strip-shaped bodies, are arrayed on one main surface of the glass substrate 71 with a resin such as an acrylic resin material, and the silver alloy AgxPdy is arranged on the strip-shaped convex array group. The film made of (x = 99.0 y = 1.0) covers the light reflection electrode 74 having a thickness of 150 nm. A large number of the light reflecting electrodes 74 are arranged in a stripe shape.

An alignment film 75 made of polyimide resin rubbed in a certain direction is formed on the light reflecting electrode 74.

With this structure, one member is used.
As for the other member, a resin color filter 76 made of an acrylic resin material or the like is formed on the glass substrate 72, and an overcoat layer 77 made of an acrylic resin containing a scattering agent and a plurality of ITOs arranged in parallel with each other. A transparent electrode 78 made of a transparent material and an alignment film 79 made of a polyimide resin rubbed in a certain direction are sequentially formed. An insulating layer made of SiO ₂ may be interposed between the transparent electrode 78 and the alignment film 79.

Then, the two substrates 71 and 72 are attached to each other by a seal member 81 via a liquid crystal 80 such as STN.
At that time, the light reflection electrode 74 and the transparent electrode 78 are crossed.

Further, a first retardation film 82 made of polycarbonate or the like, a second retardation film 83 and an iodine type polarizing plate 84 are sequentially formed on the outside of the glass substrate 72.

In the reflection type liquid crystal display device 70 having the above structure, incident light from external illumination such as sunlight or a fluorescent lamp passes through the glass substrate 72, the color filter 76 and the liquid crystal 80.
The light reflection electrode 74 is reached through
The light is reflected at and the reflected light is emitted.

When the reflective liquid crystal display device 70 of this embodiment is used while facing the device, the user usually uses it with a vertical viewing angle, especially an upward viewing angle. Therefore, the strip-shaped portions of the strip-shaped convex portions 73, which are strip-shaped bodies, are arranged laterally with respect to the panel.

In addition, as shown in Examples 2-, 2-, and 2-, the cross-sectional shape of the strip portion of the strip is
When it is asymmetrically eccentric with respect to the center line of the band, the position of the peak is set to the lower side of the reflective liquid crystal display device 70, and the incident light from above is used more effectively than in the first embodiment. ing.

The inventor prepared the conventional example (a), Example 1 and Example 2-and evaluated the optical characteristics thereof. As a result, the results shown in Table 2 were obtained.

Regarding the evaluation measurement, a reflection type liquid crystal display device 70 using each reflection plate was produced and the display performance was examined as described in (Example 3).

[0106]

[Table 2]

As is apparent from this table, the reflection type liquid crystal display device having the reflection plate of Example 1 was bright in the vertical direction. Further, in the reflection type liquid crystal display device equipped with the reflection plate of Example 2-, a reflection type liquid crystal display device having a brighter characteristic only in the upper direction was obtained.

The present invention is not limited to the above embodiment, and various modifications and improvements can be made without departing from the scope of the present invention.

For example, in this example, the STN type having a simple matrix structure is described, and the ITO stripe electrode structure is formed in this type. However, instead of this, by changing this structure, a TFT, an MIM structure, or the like is formed. An active matrix structure may be used.

Furthermore, in this example, the scattering resin layer was used as an overcoat on the color filter, but it may be formed on the reflection plate as a smooth film between the reflection plate and the color filter, or on the other side. It may be formed as a forward scattering layer on the outer surface of the glass substrate of the member.

[0111]

As described above, according to the reflector of the present invention, a plurality of linear strips are arranged so that adjacent strips are smoothly and continuously connected, and light is applied onto these strips. The reflective layer is formed, and the cross-sectional shape of the strip is
Since it is asymmetrically eccentric with respect to its center line, the reflection characteristics of the incident light can be easily controlled and the desired scattering characteristics can be achieved by simply designing the shape and configuration of the strip, making it suitable for various displays. Could be used.

Further, in the reflecting plate of the present invention, by using the photolithography technology such as development and exposure and the printing technology, there is no manufacturing variation, the manufacturing yield is increased, and a certain excellent quality is achieved. It was possible to provide a low cost reflector.

Further, according to the liquid crystal display device of the present invention, by using the reflection plate of the present invention, the reflection performance and the scattering performance with respect to the incident light can be improved, and the use performance thereof can be improved. A high-performance and low-cost liquid crystal display device suitable for a small liquid crystal panel can be provided.

[Brief description of drawings]

FIG. 1 is a process drawing of a reflector of the present invention,
(A), (b), (c), (d) is explanatory drawing of each process.

FIG. 2 is an enlarged plan view of a main part of a photomask used to manufacture the reflection plate of the present invention.

FIG. 3A is a plan view of a reflection plate of the present invention,
(B) is sectional drawing of the cutting plane line AA in the reflecting plate of (a).

FIG. 4 is an explanatory diagram showing a method for evaluating optical characteristics of a reflector.

FIG. 5 is an explanatory diagram showing a positional relationship between the orientation of the liquid crystal display device and the azimuth angle for optical characteristic evaluation.

6A and 6B are enlarged views of a photomask pattern.

FIG. 7 is a diagram showing a relationship between an azimuth angle of light incident on a reflector and its reflectance.

FIG. 8 is an enlarged plan view of a main part of a photomask used for manufacturing another reflection plate of the present invention.

FIG. 9 is an enlarged view of another photomask pattern,
(A) is an enlarged view of a main part of the light-shielding pattern, (b) is a schematic plan view showing a strip-shaped body manufactured using the photomask of (a), and (c) is a sectional plane line shown in (b). FIG.

10A and 10B are enlarged views of a main part of a light shielding pattern of a photomask.

11A, 11B, and 11C are enlarged views of a main part of a light-shielding pattern of a photomask.

12A, 12B, and 12C are enlarged views of a main part of a light-shielding pattern of a photomask.

FIG. 13 is a diagram showing a relationship between an azimuth angle of light incident on a reflector and its reflectance.

FIG. 14 is a diagram showing a relationship between an azimuth angle of light incident on another reflection plate and its reflectance.

FIG. 15 is a diagram showing a relationship between an azimuth angle of light incident on another reflection plate and its reflectance.

FIG. 16 is a cross-sectional view of a liquid crystal display device of the present invention.

FIG. 17 is a cross-sectional view of another liquid crystal display device of the present invention.

FIG. 18 is a cross-sectional view of a conventional reflective liquid crystal display device.

[Explanation of symbols]

17 ... Glass substrate 18 ... Photosensitive resin 19 ... Photomask 20 ... band 21 ... Light reflection layer 54, 70 ... Liquid crystal display device S: Shading pattern

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) G02F 1/13 505 G02F 1/13 505

Claims (5)

[Claims] 1. A plurality of linear strips are arranged on a substrate so as to smoothly and continuously connect adjacent strips, and a light reflecting layer is formed on these strips. A reflector used for display. 2. The reflector according to claim 1, wherein the cross-sectional shape of the strip is eccentrically asymmetric with respect to its center line. 3. The reflector according to claim 1, wherein a layer having a scattering property is formed on the light reflecting layer. 4. A transparent electrode and an alignment film are formed on the reflector of claim 1, 2 or 3 to form one member, and this one member is formed on the other substrate with the transparent electrode and the alignment film. A reflective or semi-transmissive liquid crystal display device in which pixels are arrayed in a matrix while being bonded to the other member via a liquid crystal. 5. A transparent electrode and an alignment film are formed on the reflection plate of claim 1 to form one member, and the other member is formed by forming the transparent electrode and the alignment film on the other substrate. A reflective or semi-transmissive liquid crystal display device in which a member and a liquid crystal are bonded together, pixels are arranged in a matrix, and a layer having a scattering property is provided on the other member.