JPH11242105A - Matrix for forming reflector and its production and reflector and its production as well as reflection type liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflector with which high reflection efficiency is obtainable over a wide angle and is brighter and whiter than heretofore. SOLUTION: A presser is pressed to the surface of a base material for a matrix and the pressing is repeated while the position of the pressure on the surface of the base material for the matrix is changed, by which many recessed parts having their inside surfaces constituting part of spherical surfaces are continuously formed on the mold surface of the base material for the matrix. Such base material is formed as the matrix for forming the reflector. A transfer mold having the mold surface reversing the rugged shapes of the mold surface of such matrix is formed and the mold surface of the transfer mold is transferred to the surface of the base material for the reflector. The reflector 1 is thus formed. The depth of the recessed parts 4 of the reflector 1 is formed to a range of 0.6 to 1.2 μm, the inclination angle distribution on the inside surface of the recessed parts 4 to -8 to +8 deg. and the pitch of the adjacent recessed parts 4 to 26.5 to 33.5 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflector having uniform brightness and whiteness over a wide range, a method of manufacturing the same, a matrix used in the manufacture thereof, a method of manufacturing the same, and a reflection type using the reflector. The present invention relates to a liquid crystal display device.

[0002]

2. Description of the Related Art In recent years, a reflection type liquid crystal display device has been widely used as a display unit of a handy type computer or the like because of particularly low power consumption. This reflective liquid crystal display device includes a reflector for reflecting light incident from the display surface side to perform display. As a conventional reflector, a reflector having a mirror-finished surface or a reflector having random irregularities formed on the surface has been used.
Among them, as shown in FIG. 9, a conventional reflector 60 having a random uneven surface has a thickness of 300 to 500, for example.
By heating a polyester film 61 of μm, an uneven surface 61 a having a height of several μm
And a reflective film 62 made of aluminum, silver, or the like is formed on the uneven surface 61a by a method such as vapor deposition.

In a conventional reflection type liquid crystal display device using a reflection plate 60 of this type, as shown in FIG. 10, transparent electrode layers 53 and 54 are provided on the inner surfaces of a pair of glass substrates 51 and 52, respectively. Further, liquid crystal alignment films 55 and 56 are provided on the transparent electrode layers 53 and 54, respectively.
The liquid crystal layer 57 is disposed between the six. Then, the first and second portions are provided outside the glass substrates 51 and 52, respectively.
Are provided, and a reflection plate 60 is attached to the outside of the second polarization plate 59 with the surface on the reflection film 62 side facing the second polarization plate 59 side.

In the reflection type liquid crystal display device 50 having the above-described structure, the light incident on the first polarizing plate 58 is linearly polarized by the polarizing plate 58, and the polarized light is elliptically polarized by transmitting through the liquid crystal layer 57. You. Then, the elliptically polarized light is linearly polarized again by the second polarizing plate 59, and
The linearly polarized light is reflected by the reflecting plate 60, passes through the second polarizing plate 59 and the liquid crystal layer 57, and exits from the first polarizing plate 58.

The reflection plate and the reflection type liquid crystal display have the following reflection characteristics. For example, as shown in FIG.
The incident angle of the incident light J from the point light source disposed on the reflective film 62 is set to an incident angle 30 with respect to the normal to the surface of the reflective film 62.
When the reflectance is measured when the reflection angle θ of the reflected light K is changed from 0 degree to 60 degrees, the reflection angle 30
It was found that the reflectance was almost the lowest when the right and left reflection angles were 20 degrees or less and 40 degrees or more with the reflectance at the peak as the peak. This tendency is similar not only to the measurement using the reflection plate alone, but also to the measurement as a whole of the liquid crystal display device provided with this reflection plate. The reflection angle at a reflection angle of 30 degrees is a peak and the reflection angle is 23 degrees. It has been found that the temperature drops to almost 0% in the range from below to 37 degrees or more.

[0006] With respect to the reflection characteristics of a reflector having a mirror-finished surface, the reflectivity generally shows a very high reflectance at a specific reflection angle with respect to the incident angle, as compared with a reflector having random irregularities on the surface. However, it has the characteristic that the range of the reflection angle with high reflectance is extremely narrow, that is, the viewing angle is narrow.

[0007]

As described above, the conventional reflector having a random concave-convex reflecting surface has a low reflectance as a whole due to poor reflection efficiency, so that incident light can be reflected over a wider range of reflection angles. It has not been possible to sufficiently meet the need for a reflector that reflects light efficiently. Therefore, the reflection type liquid crystal display device using this type of reflection plate has a problem that the brightness of the display surface is insufficient. In addition, whiteness as well as brightness is required for the characteristics of the reflector, but this type of conventional reflector does not uniformly reflect light having various wavelengths in a well-balanced manner, and therefore is insufficient in terms of whiteness of the reflection surface. Met. Further, the reflection characteristics such as the reflection angle and the reflection light intensity of this type of reflection plate are determined automatically by randomly formed irregularities, and are not controlled by optical design.

Therefore, in order to solve these problems,
A reflector having a large number of stripe grooves extending linearly on the surface has been proposed. This type of reflector can be prepared by first preparing a matrix having a large number of linear stripe grooves and transferring the mold surface of the matrix. However, in the case of this reflector, in the direction perpendicular to the stripe groove, although a desired brightness can be obtained at a certain range of reflection angle, the reflection angle range is narrow, and further, in the direction other than the direction perpendicular to the stripe groove, The reflectivity was originally low and the reflection angle was extremely narrow. Therefore, when this type of reflector is applied to a liquid crystal display device, the above-described problem that the brightness and whiteness of the display surface are insufficient, particularly in a direction parallel to the stripe groove, cannot be solved.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a reflector having sufficient brightness and whiteness, a method of manufacturing the same, a matrix used for manufacturing the reflector, and a method of manufacturing the same. It is an object of the present invention to provide a method and a reflective liquid crystal display device capable of obtaining a brighter display surface.

[0010]

In order to achieve the above-mentioned object, the reflector forming master of the present invention has a large number of recesses whose inner surface forms a part of a spherical surface formed on the surface of the base for the base. The depth of the recess is in the range of 0.6 μm to 1.2 μm, and the inclination angle distribution of the inner surface of the recess is −8 degrees to +
In the range of 8 degrees, and the pitch between adjacent concave portions is 26.5 μm.
m to 33.5 μm. In addition, the above-mentioned “depth of the concave portion” is a distance from the surface of the base material for a matrix to the bottom of the concave portion, and “a pitch of the adjacent concave portion” is a circular shape in the concave portion adjacent in one direction when viewed in plan. Means the distance between the centers of the concave portions. Further, as shown in FIG. 8, the “inclination angle of the inner surface of the concave portion” refers to the horizontal plane of the inclined surface within the minute range when a minute range of 0.5 μm width is taken at an arbitrary position on the inner surface of the concave portion 4. Angle θ with respect to The sign of the angle θ defines, for example, the right slope in FIG. 8 as positive and the left slope in FIG. 8 as negative with respect to the normal line on the reflector surface.

In the method of manufacturing a reflector forming mother die of the present invention, the indenter having a spherical tip is pressed against the surface of the mother substrate to change the position of the indenter on the surface of the mother substrate. By repeating the pressing with the indenter, a large number of concave portions whose inner surface forms a part of a spherical surface are continuously formed on the mold surface of the base material for the matrix, and at that time, the pressing depth and the moving pitch of the indenter are controlled. By doing so, the depth of the concave portion is set to 0.6 μm to 1.
2 μm, the inclination angle distribution of the inner surface of the concave portion is in a range of −8 degrees to +8 degrees, and the pitch of the adjacent concave portions is 26.5.
It is characterized in that it is in the range of μm to 33.5 μm, and the base material for the matrix having these recesses formed therein is a matrix for forming a reflector.

That is, in the method for manufacturing a reflector forming master according to the present invention, the indenter having a spherical tip is pressed against the surface of the base material for the base using a rolling device, so that the inner surface is formed into a spherical surface. This is to manufacture a reflector forming matrix in which a number of concave portions are rolled. The indenter used here is one that presses the surface of the matrix base material made of a relatively high-hardness metal material such as brass, stainless steel, tool steel, etc. extremely many times,
For example, it is desirable to use an indenter made of a material having high hardness such as diamond. Further, the rolling device repeats pressing while changing the position of the indenter on the surface of the matrix base material in order to form a large number of recesses continuously, in which case the matrix base material and the indenter are relatively horizontal. Since it is only necessary to move the inside of the base member, any of the matrix base and the indenter may be moved.

When forming the recess, the rolling device adjusts the vertical movement distance of the indenter, the relative movement distance between the matrix base material and the indenter, the diameter of the tip of the indenter, and the like. The depth of the recesses to be formed is randomly formed in the range of 0.6 to 1.2 μm, and the pitch between adjacent recesses is 26.
It is necessary to arrange them randomly in the range of 5 to 33.5 μm and set the inclination angle distribution of the inner surface of the concave portion in the range of −8 to +8 degrees.

Next, in the reflector of the present invention, a large number of concave portions whose inner surface forms a part of a spherical surface are continuously formed on the surface, and the depth of the concave portions is in a range of 0.6 μm to 1.2 μm. ,
The inclination angle distribution of the inner surface of the concave portion is in the range of -8 degrees to +8 degrees, and the pitch of the adjacent concave portions is 26.5 µm to 33.
It is characterized by being in the range of 5 μm. This reflector can be manufactured by a manufacturing method described later using the above-mentioned reflector forming matrix. In particular, it is important to set the inclination angle distribution in the range of -8 to +8 degrees. This is because, when the inclination angle distribution of the inner surface of the concave portion exceeds the range of -8 degrees to +8 degrees, the diffusion angle of the reflected light becomes too wide, the reflection intensity decreases, and a bright reflector cannot be obtained (the diffusion angle of the reflected light). Becomes 36 degrees or more in air, the reflection intensity peak inside the liquid crystal display device decreases, and the total reflection loss increases.)
Because. Also, regarding the depth of the recess, 0.6 μm
If the depth is smaller, the regular reflection becomes too strong. With respect to the pitch of the concave portions, if the pitch is smaller than 26.5 μm, it takes a long time to fabricate the reflector forming matrix. If the pitch is larger than 33.5 μm, the shape of the concave portion is visually recognized, and the quality of the reflector deteriorates.

In the method for manufacturing a reflector according to the present invention, a transfer mold having a mold surface having a shape opposite to that of the concave and convex portions of the concave portion of the reflector forming master mold is formed. The mold surface is transferred to the surface of the reflector base material, and then a reflection film is formed on the unevenness of the reflector base material surface, and this is used as a reflector.

That is, the surface of the reflector obtained by the present method reflects the mold surface of the reflector forming mother die as it is via the transfer mold, and a number of concave portions whose inner surface forms a part of a spherical surface are formed. State. Accordingly, the inclination angle (the inclination angle in a minute unit area) of the inner surface of the concave portion of the reflector, which is considered to dominate the reflection angle of the reflected light, exhibits a certain distribution within a certain angle range. Moreover, since the inner surface of the concave portion is spherical, the constant inclination angle distribution is realized not only in a specific direction but also in all directions in the reflector. Therefore, in this reflector, high reflection efficiency is obtained uniformly in all directions, and light having various wavelengths can be reflected in a well-balanced manner. That is, it is possible to realize a brighter and whiter reflector when viewed from any direction as compared with the conventional reflector.

Further, in the reflection type liquid crystal display device of the present invention, a large number of recesses whose inner surfaces form a part of a spherical surface are formed on the reflector, that is, the reflector surface, and the depth of the recess is 0.1 mm.
A reflector having a range of 6 μm to 1.2 μm, an inclination angle distribution of the inner surface of the recess in a range of −8 ° to + 8 °, and a pitch of adjacent recesses in a range of 26.5 μm to 33.5 μm is used. It is characterized by the following. The reflector may be installed in either an external type installed outside the liquid crystal cell or a built-in type installed on the inner surface of a substrate constituting the liquid crystal cell.

According to the method for manufacturing a reflection type liquid crystal display device of the present invention, the reflector itself has high reflection efficiency in all directions and has characteristics of reflecting light having various wavelengths in a well-balanced manner. It is possible to provide a reflective liquid crystal display device having a brighter display surface than the reflective liquid crystal display device.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a diagram showing a reflector according to the present embodiment. As shown in FIG. 1, the reflector 1 is provided on a surface of a flat resin substrate 3 (substrate for reflector) made of a photosensitive resin layer or the like provided on a substrate 2 made of, for example, glass. The inner surface is formed continuously so that a number of concave portions 4 forming a part of a spherical surface overlap, and a reflective film 5 made of a thin film of, for example, aluminum or silver is formed thereon by vapor deposition or printing. .

The depth of the recess 4 is set to 0.6 to 1.2 μm.
m, the pitch of the adjacent recesses 4 is randomly arranged in the range of 26.5 to 33.5 μm, and the inclination angle distribution of the inner surface of the recesses 4 is set in the range of -8 to +8 degrees. It is desirable. In particular, the inclination angle distribution
It is necessary to set in the range of 8 to +8 degrees. This is because, when the inclination angle distribution of the inner surface of the concave portion exceeds the range of -8 degrees to +8 degrees, the diffusion angle of the reflected light becomes too wide, the reflection intensity decreases, and a bright reflector cannot be obtained (the diffusion angle of the reflected light). Becomes 36 degrees or more in air, the reflection intensity peak inside the liquid crystal display device decreases, and the total reflection loss increases.)
Because. Also, regarding the depth of the recess, 0.6 μm
When it is shallower, the regular reflection becomes too strong, and when it is deeper than 1.2 μm, it becomes difficult to planarize in a later step. With respect to the pitch of the concave portions, if the pitch is smaller than 26.5 μm, it takes a long time to manufacture the reflector forming matrix. If the pitch is larger than 33.5 μm, the shape of the concave portion is visually recognized and the quality of the reflector is deteriorated.

Next, a method of manufacturing the reflector having the above-described structure will be described with reference to FIG.
This will be described with reference to FIG. In manufacturing the reflector, first, a master for forming a reflector, which is an original plate of the reflector, is prepared. The method will be described first. FIG. 2 (a)
As shown in (1), a flat plate-shaped base material 7 made of, for example, brass, stainless steel, tool steel, or the like is fixed on a table of a rolling device. Then, the surface of the matrix substrate 7 is pressed by a spherical diamond indenter 8 having a predetermined diameter R at the tip, and the matrix substrate 7 is moved in the horizontal direction, and the diamond indenter 8 is moved up and down. By repeatedly performing the pressing and pressing operation a number of times, a large number of recesses 7a having different depths and arrangement pitches are rolled on the surface of the base material 7 for a matrix, and FIG.
And a matrix 9 for forming a reflector as shown in FIG. As shown in FIG. 3, the rolling device used here has a table for fixing the matrix base material 7 with a resolution of 0.1 μm in the X direction in the horizontal plane.
It has a function of moving in the Y direction and moving the diamond indenter 8 in the vertical direction (Z direction) with a resolution of 1 μm. The diameter R of the tip of the diamond indenter 8 may be, for example, about 135 μm.

The procedure of rolling with a diamond indenter is as follows. FIG. 4 is a plan view showing a rolling pattern. As shown in FIG. 4, the pitches of the adjacent concave portions in one horizontal row are odd rows such as the first row, the third row,. In the eyes, t1 (= 33.5) in order from the left end
μm), t2 (= 30 μm), t3 (= 26.5 μm),
This is the repetition of t2. .., T2, t2, and t3 are repeated in order from the left end in the even-numbered row, such as the second row, the fourth row, and so on, counting from the top. The positions of the concave portions are shifted by about half the diameter of the concave portions in the lateral direction. The pitch between rows in the vertical direction is s3 (= 17 μm) and s2 (= 19
μm), s2, and s1 (= 20 μm). Then, by setting four kinds of depths of the concave portions in the range of 0.6 to 1.2 μm (indicated as d1, d2, d3 and d4 in the figure) and pressing, the circular concave portions which are the indentations after pressing are formed. There are also four types of radii, r1, r2, r3, and r4. For example, the depth of the concave portion in the top row is d1, d2,
d3, d4, d1, d2, d3, d4, d1.

For the actual rolling order, for example, after forming concave portions in order from the left end to the right end in the uppermost row, the same operation as the second row, the third row,... Good. Alternatively, after forming the concave portion at the left end in order from top to bottom, the same operation as the second column, third column,... From the left may be repeated. Thus, all the concave portions in the pattern are formed. Ideally, it is desirable that the depths and pitches of the concave portions are arranged completely at random. However, since it is difficult in terms of manufacturing technology, the entire reflector is formed by repeating such a pattern. This repetition period is desirably 150 μm or more, and the longer the period, the better. Further, as shown in FIG. 4, since the indentations of the adjacent concave portions partially overlap, the planar shape of the entire concave portion after all the rolling operations are completed is as shown in FIG. Thus, the reflector forming matrix 9 is completed. Thereafter, when manufacturing a reflector, a large number of reflectors can be manufactured by repeatedly using the matrix 9.

In the case of the above-described rolling device, the table on which the base material for the matrix is fixed moves in a horizontal plane.
It is only necessary to move the position of the diamond indenter on the surface of the matrix substrate, so that the indenter side may move in the horizontal direction. The material of the base material for the matrix is not limited to brass, stainless steel, tool steel, and the like, and various metal materials having high hardness can be used. Also,
The indenter that presses the matrix substrate is not limited to diamond as long as it is made of a material having high hardness.

Thereafter, as shown in FIG.
Is placed and placed in a box-shaped container 10, a resin material 11 such as silicone is poured into the container 10, left to cure at room temperature, and the cured resin product is taken out of the container 10 and unnecessary portions are cut off. As shown in FIG. 2D, a transfer mold 12 having a mold surface 12a having a large number of concave portions forming the mold surface of the matrix 9 and a large number of convex portions having the opposite concave and convex shape is formed.

Next, a photosensitive resin liquid such as an acrylic resist, a polystyrene resist, an azide rubber resist, or an imide resist is applied on the upper surface of the glass substrate by a coating method such as spin coating, screen printing, or spraying. I do. After completion of the coating, the photosensitive resin liquid on the substrate is prebaked by using a heating device such as a heating furnace or a hot plate in a temperature range of, for example, 80 to 100 ° C. for 1 minute or more. Form a layer. However, since the pre-bake conditions differ depending on the type of the photosensitive resin used, it is needless to say that the treatment may be performed at a temperature and a time outside the above range. The thickness of the photosensitive resin layer formed here is preferably in the range of 2 to 5 μm.

Thereafter, as shown in FIG.
After using the transfer mold 12 shown in (d) and pressing the mold surface 12a of the transfer mold 12 against the photosensitive resin layer 3 on the glass substrate for a predetermined time, the transfer mold 12 is removed from the photosensitive resin layer 3. In this way, as shown in FIG. 2 (f), the convex portions of the transfer mold surface 12a are transferred to the surface of the photosensitive resin layer 3 to form a large number of concave portions 4. Further, it is preferable to select a value corresponding to the type of the photosensitive resin to be used for the pressing pressure at the time of embossing,
For example, the pressure is preferably about 30 to 50 kg / cm ² . It is preferable to select a value corresponding to the type of the photosensitive resin to be used for the pressing time, for example, 30 seconds to 10 seconds.
It takes about a minute.

Thereafter, ultraviolet rays (g, h, i) for curing the photosensitive resin layer 3 from the back side of the transparent glass substrate.
The photosensitive resin layer 3 is cured by irradiating a light beam such as a line).
In the case of a photosensitive resin layer of the above type, the intensity of 50 mJ / cm ² or more is sufficient to cure the photosensitive resin layer. It is needless to say that the irradiation may be performed at other intensity depending on the case. Then, the photosensitive resin layer 3 on the glass substrate is post-baked by heating the photosensitive resin layer 3 on the glass substrate at, for example, about 240 ° C. for 1 minute or more by using a heating device such as a heating furnace or a hot plate used in the pre-baking. Is baked.

Finally, for example, aluminum is formed on the surface of the photosensitive resin layer 3 by electron beam evaporation or the like, and the reflection film 1 is formed along the surface of the concave portion.
The reflector 1 of the present embodiment is completed.

In the reflector 1 obtained by the manufacturing method of the present embodiment, a large number of recesses 4 whose inner surfaces are part of a spherical surface are formed on the surface, and the depth of the recess 4 and the depth of the adjacent recess 4 By setting the value of the pitch or the like in the above range, the inclination of the inner surface of the concave portion shows a constant distribution in a certain angle range. FIG. 6 shows the result of actually measuring the distribution of the inclination angle of the inner surface of the concave portion of the reflector 1.
The horizontal axis indicates the inclination angle, and the vertical axis indicates the frequency at which the inclination angle exists. As shown in this figure, the inclination angle is -8 to +8.
It shows a substantially constant distribution in the range of degrees, especially in the range of -4 to +5 degrees. Further, since the inner surface of the concave portion 4 is spherical and symmetrical with respect to all directions, this constant inclination angle distribution is not only in a specific direction in the reflector, but also in a certain direction.
Realized in all directions. It is considered that the inclination angle of the inner surface of the concave portion governs the reflection angle of the reflected light on the inner surface of the concave portion. In the case of this embodiment, since the inclination angle distribution is constant in all directions of the reflector, As a result, uniform reflection angles and reflection efficiencies can be obtained, and light having various wavelengths can be reflected in a well-balanced manner. That is, it is possible to realize a brighter and whiter reflector when viewed from any direction as compared with the conventional reflector.

In the method of manufacturing the reflector forming die according to the present embodiment, the diamond indenter 8 is moved up and down to press the surface of the substrate 7 for forming the concave portion. Therefore, the diamond indenter 8 does not rub against the base material 7 for a matrix. As a result, the surface state of the tip of the diamond indenter 8 is reliably transferred to the matrix 9 side, and the indenter 8
If the tip of the mirror is mirror-finished, the inner surface of the concave portion of the matrix 9 and, consequently, the inner surface of the concave portion of the reflector can be easily mirror-finished. Furthermore, unlike conventional reflectors that have formed an uneven surface by heating a resin film such as polyester,
The depth, diameter, pitch, and other dimensions of the recess in the reflector 1 of the present embodiment, the surface condition of the inner surface of the recess, and the like are all controlled, and the concave shape of the reflector is increased by using a high-precision rolling device. Can be created almost as designed. Therefore, according to the present method, the reflection characteristics such as the reflection angle and the reflection efficiency of the reflection plate to be produced become easier to control than in the past, and a desired reflector can be obtained.

It should be noted that specific numerical values such as the depth, diameter, pitch and the like of the concave portion 4 of the reflector 1 in the present embodiment and the rolling pattern of the concave portion shown in FIG. Is of course possible. Also, a substrate for a reflector,
The materials of various base materials such as the base material for the matrix, the constituent materials of the transfer mold, and the like can be appropriately changed.

Next, an STN (Supe) equipped with the above-mentioned reflector is used.
r Twisted Nematic) type reflective liquid crystal display device will be described. As shown in FIG. 7, this reflection type liquid crystal display device has a liquid crystal layer 15 provided between a pair of display side glass substrates 13 and a rear side glass substrate 14 having a thickness of, for example, 0.7 mm. One phase difference plate 16 made of a polycarbonate resin, a polyarylate resin, or the like is provided on the upper surface side of 13, and a first polarizing plate 17 is provided on the upper surface side of the phase difference plate 16. On the lower surface side of the rear glass substrate 14, a second polarizing plate 18 and the reflector 1 shown in FIG. 1 manufactured in advance by the above-described method are sequentially provided.

The reflector 1 is mounted on the lower surface side of the second polarizing plate 18 such that the surfaces on which the recesses 4 are formed face each other, and a gap between the second polarizing plate 18 and the reflector 1 such as glycerin is provided. An adhesive 19 made of a material that does not adversely affect the refractive index of light is filled. Transparent electrode layers 20 and 21 made of ITO (indium tin oxide) or the like are formed on the facing surfaces of the two glass substrates 13 and 14, respectively.
Alignment films 22 and 2 made of polyimide resin or the like on 0 and 21
3 are provided. These alignment films 22 and 23
The liquid crystal in the liquid crystal layer 15 is arranged to be twisted by 240 degrees due to the relationship (1).

Further, a color filter (not shown) may be formed between the rear glass substrate 14 and the transparent electrode layer 21 by printing or the like, so that the liquid crystal display device can perform color display.

In the reflection type liquid crystal display device obtained by the manufacturing method of the present embodiment, as described above, the reflector 1 used has a wide reflection angle of incident light in all directions and a high reflection efficiency. Due to its characteristics, even if the user sees the display surface from any direction,
A liquid crystal display device having a brighter display surface than a conventional liquid crystal display device can be provided.

In the method of the present embodiment, an example has been described in which the reflection plate is provided outside the second polarizing plate, that is, a so-called external reflection plate. And may be built-in type. In addition, although the description has been given of the STN mode as an example of the liquid crystal display device, a TN (Twisted Nemati) in which the twist angle of the liquid crystal molecules of the liquid crystal layer is set to 90 degrees.
Of course, the reflector of the present invention can be applied to the liquid crystal display device of the c) type.

[0038]

As described above in detail, in the reflector of the present invention, a large number of concave portions whose inner surfaces are part of a spherical surface are formed on the surface, and the depth and pitch of the concave portions are within a certain range. By the control, the inclination angle distribution of the inner surface of the concave portion becomes almost constant in the angle range of -8 degrees to +8 degrees with respect to all directions of the reflector, so that uniform reflection efficiency can be obtained in all directions. And light having various wavelengths can be reflected in a well-balanced manner. That is, according to the present manufacturing method, it is possible to realize a brighter and whiter reflector when viewed from any direction as compared with the conventional reflector. In addition, in the method of manufacturing a reflector forming master, it is only necessary to press the surface of the master base using an indenter when forming the concave portion, so that the indenter and the master base are rubbed. There is no. As a result, the surface state of the tip of the indenter is reliably transferred to the matrix side. For example, if the tip of the indenter is set to the mirror state, the inner surface of the concave portion of the mother mold, and eventually the inner surface of the concave portion of the reflector can be easily made to the mirror surface state. . Further, unlike the conventional reflector, the depth, diameter, pitch, and other dimensions of the recess of the reflector according to the present invention, the surface condition of the inner surface of the recess, and the like are all controlled, and the recess shape of the reflector is almost designed. Can be created as street. Therefore, using the reflector forming matrix obtained by the present method makes it easier to control the reflection characteristics such as the reflection angle and the reflection efficiency of the reflector to be produced as compared with the related art, and obtains a desired reflector. be able to. According to the reflection type liquid crystal display device of the present invention, a liquid crystal display device having a brighter white display surface can be realized by using the reflector having the above excellent characteristics.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a reflector according to an embodiment of the present invention.

FIG. 2 is a process flow chart showing a manufacturing process of the reflector in order.

FIG. 3 is a view showing one process of manufacturing a matrix used for forming a reflector, showing a state in which a matrix for a matrix is pressed by a diamond indenter.

FIG. 4 is a plan view showing a pattern of rolling by a diamond indenter in a manufacturing process of the matrix.

FIG. 5 is a plan view showing the shape of the entire recess after rolling.

FIG. 6 is a diagram showing a distribution of an inclination angle of an inner surface of a concave portion in the reflector.

FIG. 7 is a cross-sectional view illustrating a reflective liquid crystal display device according to an embodiment of the present invention.

FIG. 8 is a view for explaining an inclination angle of an inner surface of a concave portion of the reflector according to the present invention.

FIG. 9 is a perspective view showing an example of a conventional reflector.

FIG. 10 is a cross-sectional view illustrating an example of a conventional reflective liquid crystal display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reflector 2 Substrate 3 Resin base material (reflector base material) 4,7a recessed part 5 Reflective film 7 Matrix base material 8 Diamond indenter 9 Reflector forming base mold 12 Transfer mold

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Mitsuru Kano 1-7 Yukitani-Otsuka-cho, Ota-ku, Tokyo Alps Electric Co., Ltd.

Claims (5)

[Claims] 1. A large number of recesses having an inner surface forming a part of a spherical surface are continuously formed on a surface of a matrix substrate, and a depth of the recesses is in a range of 0.6 μm to 1.2 μm. The inclination angle distribution of the inner surface of the concave portion is in the range of -8 degrees to +8 degrees, and the pitch of adjacent concave portions is 26.5 μm to 33.5 μm.
A reflector forming matrix. 2. An indenter having a spherical tip is pressed against the surface of the matrix substrate, and the pressing by the indenter is repeated while changing the position of the indenter on the surface of the matrix substrate. A large number of recesses whose inner surface forms a part of a spherical surface are continuously formed on the mold surface of the base material. At this time, the depth of the recesses is set to 0. 0 by controlling the pressing depth and the moving pitch of the indenter. The range of 6 μm to 1.2 μm, the inclination angle distribution of the inner surface of the recesses in the range of −8 ° to + 8 °, the pitch of adjacent recesses in the range of 26.5 μm to 33.5 μm, A method for producing a reflector forming matrix, wherein the mold base is a reflector forming matrix. 3. A plurality of recesses whose inner surface forms a part of a spherical surface are continuously formed on the surface, the depth of the recesses is in a range of 0.6 μm to 1.2 μm, and the inclination angle distribution of the inner surface of the recesses. Wherein the pitch of adjacent concave portions is in a range of 26.5 μm to 33.5 μm. 4. A transfer mold having a mold surface having a shape opposite to that of the mold surface on which the concave portion is formed in the master for forming a reflector according to claim 1, and reflecting the mold surface of the transfer mold. A method for producing a reflector, comprising transferring the film onto a surface of a body for a body, forming a reflection film on the unevenness of the surface of the body for a reflector, and using the film as a reflector. 5. A reflective liquid crystal display device comprising the reflector according to claim 3.