JPH0980426A - Reflection plate and its production as well as reflection type liquid crystal display panel formed by using this reflection plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to produce a reflection plate having good visibility and directivity. SOLUTION: Many fine sectorial projecting parts 1a are formed on the surface of the reflection plate 1 installed on the panel inner side of a back substrate 2 of a reflection type liquid crystal display panel. The vertexes of these projecting parts 1a are maldistributed toward the lower side of the panel in a use state and the flanks thereof are inclined. The angle α of inclination of the slopes which are on the upper side of the panel in the use state are set smaller than the angle β of inclination of the slopes which are on the lower side of the panel to incline the slopes on the upper side of the panel more gently than the slopes on the lower side of the panel. As a result, the reflection area on the upper side of the panel is widened to reflect the external light from the upper direction and lateral direction of the panel more to the front surface of the panel. A good reflection characteristic and visibility are imparted to the reflection type liquid crystal display panel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection plate, a method for manufacturing the same, and an improvement of a reflection type liquid crystal display panel using the reflection plate, and more particularly to a countermeasure against visual recognition.

[0002]

2. Description of the Related Art Liquid crystal display panels have been applied to word processors, laptop personal computers, car navigation systems, etc. in recent years by taking advantage of the features of thinness, light weight and low power consumption. In particular, a reflective liquid crystal display panel that uses external light does not require a backlight, so that it is possible to significantly reduce power consumption and further reduce the thickness and weight. Display modes of such a reflective liquid crystal display panel include a twist nematic (TN) method and a super twist nematic (STN) method that require a polarizing plate, and a guest-host method and a polymer dispersion method that do not require a polarizing plate. .

In a reflection type liquid crystal display panel, since there is no backlight, it is important to select a liquid crystal mode in which the transmittance of the liquid crystal cell is increased and the reflection brightness is increased. In the mode requiring the polarizing plate, there is an advantage that the black can be surely produced by aligning the polarization axes, but the reflected light becomes half of the incident light. on the other hand,
In the mode that does not require a polarizing plate, the contrast is slightly low, but the reflected brightness is high.

In the reflection type liquid crystal display panel, it is essential to improve the reflection characteristics of the reflection plate. As a method of improving the reflection characteristics of the reflector, in order to make the display of the liquid crystal easy to read from any angle, contact the metal foil surface with a concavo-convex roll to shape the concavities and convexities, and to improve the light reflection on the metal foil surface. A non-directional method (Japanese Unexamined Patent Publication No. 3-246502) or a method in which a matte aluminum alloy foil is stretched uniaxially to obtain an optically non-directional and high diffuse reflectance (Japanese Unexamined Patent Publication No. Sho 64-64- Japanese Patent No. 66687) has been proposed.

As an example in which the reflection characteristic has directivity, a sawtooth shape is used in which the viewing angle direction is a slope on the surface of the reflector so that the perpendicular to the reflecting surface of the reflector and the perpendicular to the front surface of the panel intersect at an angle. Method (Japanese Patent Laid-Open No. Sho 6
1-270731 gazette) is proposed.

[0006]

By the way, as a field to which the reflection type liquid crystal display panel is applied, the mobile terminal is most effective. A mobile terminal mainly used for personal use does not require a wide viewing angle, and there is no problem if the display can be read at a specific viewing angle that allows the user to easily handle the mobile terminal.

However, in the conventional method of making the light reflection on the surface of the metal foil omnidirectional, the light reflected from the reflection plate is scattered as much as possible, so that the panel reflection brightness in front of the user is low. turn into.

Further, in the method of forming a sawtooth shape in which the surface of the reflecting plate has a slope in the viewing angle direction, light reflection having directivity is obtained, but the viewing angle range of high brightness becomes very narrow,
External light from above the panel is effectively reflected, but external light from diagonally above and lateral directions cannot be used.

In the method of uniaxially stretching the metal foil, a large number of very elongated elliptical projections having a long axis in the axial direction can be obtained on the surface of the metal foil. The reflection characteristic of this reflector has a gentle reflection intensity distribution along the axial direction with the peak in the regular reflection direction as the apex. However, in the direction perpendicular to the axis, the inclination angle of the elliptical projection changes abruptly, and the light reflected at a large angle is reflected at the interface between the glass and air and cannot reach the outside of the cell, so that the reflection intensity drops sharply.

The present invention has been made in view of the above points, and an object thereof is to provide a reflector having good visibility and directivity, a method for manufacturing the same, and a reflective liquid crystal display using the reflector. It is to provide a panel.

[0011]

In order to achieve the above-mentioned object, the present invention has variously devised the shape of the projection formed on the reflection plate. Specifically, the following means for solving the problems are provided. I took it.

That is, the first to seventh means of the present invention is a reflection type in which a liquid crystal is interposed between a pair of front and rear substrates provided with electrodes, and a reflector is attached inside or outside the panel of the rear substrate. The present invention relates to the reflection plate of a liquid crystal display panel, and the first solution is that the reflection plate has a large number of fine projections on its surface. At this time, the apex of the protrusion is ubiquitous in the lower side of the panel in the use state and the side surface is inclined, and the inclination angle of the inclined surface on the upper side of the panel in the used state is smaller than that of the inclined surface on the lower side of the panel. It is characterized in that it is made smaller and the inclined surface on the upper side of the panel is inclined more gently than the inclined surface on the lower side of the panel.

The second solving means is characterized in that, in the first solving means, the protrusion is formed in a stripe shape extending in parallel to the left and right sides of the panel in a used state.

The third solving means is characterized in that, in the first solving means, the projection is formed into a substantially fan shape.

A fourth solution means is characterized in that, in the first solution means, the projection is formed into a perfect circular shape.

A fifth solving means is characterized in that, in the first solving means, the projection is formed in a horizontally elongated elliptical shape.

In the sixth solving means, on the premise as described above, the reflecting plate has a large number of fine projections on its surface. At this time, the protrusion is formed in a columnar shape, and is gently inclined obliquely downward from the base surface to the panel in a used state.

In the seventh solving means, on the premise as described above, the reflecting plate has a large number of fine projections on its surface. At this time, the protrusion is formed into a horizontally long elliptical shape, and the peripheral surface is gently inclined with the central portion as the apex.

The eighth to tenth means for solving the problems of the present invention relate to a method for manufacturing the above-mentioned reflector. An eighth solving means relates to a manufacturing method of the reflecting plate of the fifth solving means, and first, the surface of the metal film is brushed in a left-right direction of the panel in a used state. After that, by brushing the metal film surface while weakening the strength in the vertical direction of the panel in use, the metal film surface has a large number of minute oblong elliptical projections, and the peaks of the projections are In the use state, it is ubiquitous on the lower side of the panel and its side surface is inclined, and the inclination angle of the inclined surface which is the panel upper side in the used state is smaller than the inclination angle of the inclined surface which is the panel lower side, and is the panel upper side. A feature of the present invention is to obtain a reflection plate in which the inclined surface is more gently inclined than the inclined surface on the lower side of the panel.

A ninth solving means of the present invention relates to a method for manufacturing a reflecting plate of the sixth solving means, wherein a large number of fine columnar shapes are obtained by obliquely vapor-depositing metal from below toward the base. It is characterized in that the projection obtains a reflection plate which is gently inclined from the base surface to the panel obliquely downward.

A tenth solution means of the present invention relates to a method for manufacturing a reflection plate of the seventh solution means, in which a metal foil is biaxially stretched to form a large number of fine oblong elliptical shapes on the surface. It is characterized in that it has a projecting part, and the peripheral surface of this projecting part obtains a gently inclined reflector plate with the central part as the apex.

The eleventh and twelfth solving means of the present invention relates to a reflection type liquid crystal display panel using the reflection plate as described above. The eleventh solving means is between a pair of front and rear substrates provided with electrodes. The liquid crystal is inserted in. Furthermore, the reflecting plate of any one of the first to seventh solving means is attached to the outside of the panel of the rear substrate.

A twelfth means for solving the problems is to interpose a liquid crystal between a pair of front and rear substrates provided with electrodes. Further, the reflector of any one of the first to seventh solving means is attached to the inside of the panel of the rear substrate. At this time, it is characterized in that the reflecting plate also functions as an electrode.

With the above arrangement, the following actions and effects can be obtained in the first to twelfth solving means of the present invention. Before that, the use state will be described. In the reflection type liquid crystal display panel, external light is reflected by a reflection plate for display. The external light source is almost always the sun outdoors and the ceiling light indoors, and these are located above or lateral to the panel. It is considered that there are very few outside light sources below the panel, so it can be said that the structure that takes in the maximum amount of outside light from above and lateral directions of the panel and reflects it to the front of the panel has the best reflection efficiency. .

Therefore, according to the first solution of the present invention, the inclination of the inclined surface on the upper side of the panel is gentle when a large number of minute projections formed on the surface of the reflection plate are used, so that The reflection area on the upper side expands, and more external light from the panel upper direction is reflected on the front surface of the panel.

In the second solution of the present invention, due to the stripe shape of the protrusions, the external light from the panel upper direction is efficiently transmitted to the front surface of the panel by the gently inclined surface on the panel upper side of the protrusions formed on the reflector plate surface. It reflects well.

In the third to fifth means for solving the problems of the present invention, due to the substantially fan shape, the perfect circle shape, and the oblong elliptical shape of the projecting portion, the external light from the panel upper direction and the lateral direction is formed on the reflecting plate surface. The gentle slopes on the upper and lateral sides of the panel allow efficient reflection on the front of the panel.

In the sixth solution of the present invention, a large number of fine columnar projections projecting from the base surface are gently inclined obliquely downward in the panel in use, so that the panel can be moved upward and laterally. The outside light from is reflected efficiently on the front of the panel.

In the seventh means for solving the problems of the present invention, a large number of fine projections formed on the surface of the reflecting plate have a horizontally elongated elliptical shape in which the peripheral surface is gently inclined with the central portion as the apex.
Incident light from the vertical direction of the panel is efficiently reflected to the front of the panel.

In the eighth means for solving the problems of the present invention, first, the shape of an ellipse having an ellipse having a major axis in the lateral direction is obtained by first brushing on the surface of the metal film, and then the elliptical projection is weakly brushed. The inclination angle on the upper side / lateral side of the panel becomes gentler than the inclination angle on the lower side of the panel, resulting in the horizontally elongated elliptical shape of the fifth solving means. Therefore, external light from the upward and lateral directions of the panel is efficiently reflected to the front surface of the panel by the gently sloped surfaces on the upper and lateral sides of the panel of the protrusion formed on the surface of the reflector.

In the ninth solution of the present invention, when metal is obliquely vapor-deposited from below toward the base, a large number of fine columnar projections project obliquely downward from the base surface, and the sixth The solution reflector is easily obtained.

In the tenth means for solving the problems of the present invention, the fine projections on the surface of the reflecting plate have a major axis in the axial direction by first stretching the metal foil in one axial direction (for example, the lateral direction). A very elongated elliptical protrusion shape is obtained, and by further extending this in the other axial direction (for example, the longitudinal direction), an elliptical protrusion shape close to a circle is obtained. It becomes an elliptical shape. As described above, the inclination angle of the elliptical protrusion is gently changed by stretching in the biaxial direction, so that the proportion of light reflected at a large angle and not reaching the outside of the cell is reduced. Therefore, the reflection characteristic of this reflector is
If the angle is increased along the axial direction starting from the angle having the largest reflection intensity in both the horizontal and vertical directions, the change in the reflection intensity becomes less rapid.

In the eleventh and twelfth solving means of the present invention, due to the reflection characteristics of the reflection plate as described above, incident light from above the panel, obliquely above, or from the lateral direction is efficiently reflected to the front of the panel and is a bright reflection type. A liquid crystal display panel can be obtained.

[0034]

Embodiments of the present invention will be described below with reference to the drawings.

Example 1 FIGS. 1A and 1B show a reflector 1 according to Example 1 of the present invention, and as shown in FIG.
The reflector 1 is attached to the inner surface of the glass substrate 2 behind the reflective liquid crystal display panel. A large number of fine stripe-shaped projections 1a are formed on the surface of the reflection plate 1, and the projections 1a are arranged so as to extend parallel to the left and right sides of the panel in a used state. In addition, the apex of the protrusion 1a is ubiquitous in the lower part of the panel in the used state and both upper and lower side surfaces thereof are inclined, and the inclination angle α of the inclined surface which is the upper side of the panel in the used state is the inclined surface which is the lower side of the panel. The inclination angle β is smaller than the inclination angle β, and the inclined surface on the upper side of the panel is inclined more gently than the inclined surface on the lower side of the panel. This reflector 1
It is formed by bringing a roll having a stripe-shaped concavo-convex structure into contact with the surface on which a metal such as Al, Ni, or Ag is deposited to form a thin film, and then shaping. The width W1 of the stripe-shaped protrusion 1a after shaping is 15 μm, and the height H is 2 μm.
The distance W2 between the adjacent protrusions 1a is 5 μm, and the side where the protrusions 1a are gently inclined is the upper side of the panel.

FIG. 2 shows a method of measuring the reflection characteristic of the reflector 1. The model of the reflection type panel used for this measurement is manufactured by bonding a dummy glass having a refractive index almost equal to that of the liquid crystal on the reflection plate 1 with an ultraviolet curing resin having a refractive index also equal to that of the liquid crystal.
The model of this reflection type panel is installed horizontally as the measurement target 7, light is incident from the incident light source 4 at an angle θ and a rotation angle ψ, and the reflection intensity R in the front direction is measured by the photomultimeter 3. did.

FIG. 3 shows the reflection characteristics of the reflection plate 1 of the first embodiment. FIG. 3 (a) shows the measurement system of FIG.
The reflection intensity R on the front surface of the reflecting plate 1 when the incident angle θ is set to be fixed at 90 °, 180 °, 225 °, and 270 ° is represented by the distance from the origin O. FIG. 3B shows the reflection intensity R when the incident angle θ is fixed at 30 ° and the rotation angle ψ is swung in the measurement system of FIG.

From FIGS. 3A and 3B, the reflector 1 is
It can be seen that the reflection intensity R of the incident light from above the panel is large.

FIG. 4 shows a reflection type liquid crystal display panel manufactured by using the reflection plate 1 having the stripe-shaped protrusions 1a. This reflection type liquid crystal display panel is provided with a pair of front and rear glass substrates 2. Inside the panel of the glass substrate (active matrix substrate) 2 which is the front (upper side in FIG. 4) in use, the pixel electrodes 10 and the pixels are provided. The thin film transistor (hereinafter referred to as a TFT element) 9 provided in the panel is disposed inside the panel of the glass substrate 2 which is the rear side (the lower side in FIG. 4) in use, and the reflection plate 1 also serving as the counter electrode is provided on the loose side of the protrusion 1a. The liquid crystal 5 and the spacer 8 are provided between the glass substrates 2 with the inclined surface of the glass substrate 2 facing the upper side of the panel. When enclosing the liquid crystal 5, first, an alignment film is applied on both glass substrates 2 and a particle size of 6 μm is applied between both glass substrates 2.
m spacers 8 are sprinkled, a sealant is printed on the peripheral portion, and then the pieces are attached. Next, a guest-host liquid crystal 5 having a chiral pitch of 3.5 μm mixed with a black dye is vacuum-injected and then sealed.

FIG. 5 shows a voltage-reflectance characteristic diagram of the reflection type liquid crystal display panel of FIG. The measurement was performed by using the measurement system shown in FIG. 2 and arranging so that the glass substrate 2 on the side where the reflection plate 1 was attached became the lower substrate. The reflectance Rf was determined by the ratio of the intensity of the diffused light of the reflective liquid crystal display panel to the diffused light from the standard white plate at the incident angle θ = 30 °.

From FIG. 5, the reflectance Rf for the incident light from above the panel reached about 50%, and the contrast was 10-15.

When the liquid crystal display panel of FIG. 4 was observed under normal illumination, the screen was very bright and had a high contrast.

As described above, by using the reflection plate 1 having the stripe-shaped protrusions 1a of Example 1, incident light from above the panel is efficiently reflected to the front of the panel, and a bright reflection type liquid crystal display panel can be provided. .

(Embodiment 2) FIGS. 6A and 6B show a reflector 1 according to Embodiment 2, in which the projection 1a is fan-shaped. This reflector is made of Al, N
It is formed by bringing a roll having a fan-shaped concavo-convex structure into contact with the surface of a thin film formed by vapor-depositing a metal such as i or Ag to form a pattern. Fan-shaped projection 1 after shaping
The horizontal width W3 of a is 25 μm, and the vertical width W4 is 15 μm.
The height H was 2 μm. The apex of the protrusion 1a is ubiquitous in the lower part of the panel in use, and both upper and lower surfaces thereof are inclined, and the inclination angle α of the inclined surface on the upper side of the panel in use is the inclination of the inclined surface on the lower side of the panel. The angle is smaller than the angle β, and the inclined surface on the upper side of the panel is inclined more gently than the inclined surface on the lower side of the panel. That is, the apex of the protrusion 1a is formed in a portion close to the central angle of the fan shape, and the side surface is inclined while gently drawing a curved surface toward the arc of the fan shape. Then, the side of the arc with a gentle inclination angle of the protrusion 1a was set as the upper side of the panel in use. However, in FIG. 6, although the distance between the adjacent protrusions 1a is illustrated to be large, the protrusions 1a are arranged so that the actual distance becomes smaller.

Similar to the first embodiment, FIG. 7 shows the result of measurement of the reflection characteristics of the reflection plate 1 having the fan-shaped protrusions 1a of the second embodiment.

From FIGS. 7A and 7B, the reflector 1 is
It can be seen that the reflection intensity R of the incident light not only from above the panel but also obliquely above and laterally increases.

Similar to the first embodiment, FIG. 8 shows the measurement result of the voltage-reflectance characteristic of the reflection type liquid crystal display panel manufactured by using the reflection plate 1 having the fan-shaped projections 1a of the second embodiment. .

From FIG. 8, the reflectance Rf for incident light from above the panel, obliquely above, and lateral direction is about 50% to 20%.
And the contrast was 10-15.

When the liquid crystal display panel provided with the reflector 1 was observed under normal illumination, the screen was very bright.
The contrast was also high.

As described above, by using the reflection plate 1 having the fan-shaped projections 1a of the second embodiment, incident light from above the panel, obliquely above, and laterally is efficiently reflected to the front of the panel and is bright. A reflective liquid crystal display panel can be provided.

(Third Embodiment) FIGS. 9A and 9B show a reflector 1 according to the third embodiment. In this third embodiment, the projection 1a is formed.
Has a perfect circular shape. This reflector 1 is made of Al, Ni,
It is formed by contacting a roll having a circular concavo-convex structure on the surface of the base 1b on which a metal such as Ag is vapor-deposited to form a thin film, and shaping. The diameter D1 of the circular protrusion 1a after shaping was 15 μm and the height H was 2 μm. The apex of the protrusion 1a is ubiquitous in the lower part of the panel in use, and both upper and lower surfaces thereof are inclined, and the inclination angle α of the inclined surface on the upper side of the panel in use is the inclination of the inclined surface on the lower side of the panel. The angle is smaller than the angle β, and the inclined surface on the upper side of the panel is inclined more gently than the inclined surface on the lower side of the panel. That is, the apex of the protrusion 1a is formed in a portion close to a part of the arc from the center of the circle, and is inclined while gently drawing a curved surface toward the arc. The side of the arc where the inclination angle of the protrusion 1a is gentle was set as the panel upper side in use. However,
In FIG. 9 as well, the gap between the adjacent protrusions 1a is illustrated to be large, but the protrusions 1a are arranged so that the actual gap is narrower.

The reflection characteristics of the reflection plate 1 were measured in the same manner as in Example 1.

The reflection characteristic of the reflector 1 having the circular protrusion 1a of the third embodiment is similar to that of FIG.
It is understood that the reflection intensity R of incident light from not only above the panel but also obliquely above and in the lateral direction is high.

FIG. 10 shows a circular protrusion 1 according to the third embodiment.
1 shows a reflection type liquid crystal display panel manufactured using the reflection plate 1 having a. In the liquid crystal display panel of FIG. 10, the reflection plate 1 is provided at the rear (lower side of FIG. 10) of the glass substrate 2 in the use state, and the gentle slope of the protrusion 1a is provided toward the upper side of the panel. The configuration is similar to that of the first embodiment except that the counter electrode 11 is provided inside the panel of the glass substrate 2, and thus detailed description thereof is omitted.

When the voltage-reflectance characteristic of the reflection type liquid crystal display panel of FIG. 10 was measured according to the method of Example 1, the reflectance Rf for incident light from above the panel, obliquely above and lateral direction was the same as in FIG. Reached about 50% to 20%, and the contrast was 10 to 15.

When the liquid crystal display panel provided with the reflector 1 was observed under normal illumination, the screen was very bright.
The contrast was also high.

As described above, the protrusion 1a having a perfect circular shape according to the third embodiment is used.
By using the reflector 1 having
It is possible to provide a bright reflective liquid crystal display panel by efficiently reflecting incident light from diagonally upper and lateral directions to the front of the panel.

(Embodiment 4) FIGS. 11A and 11B show a reflector 1 according to Embodiment 4, in which the projection 1a of the reflector 1 has a columnar shape. This reflector 1 is made of Al, Ni, A
A large number of fine columnar protrusions 1a are formed on the surface by performing a metallization of g or the like on the base 1b in an 80 degree rotary oblique deposition. The columnar protrusions 1a are formed from the base surface in use. It inclines gently diagonally down the panel. The columnar protrusion 1a has a diameter D2 of 0.2 μm and a length L of 1 μm.
m and the inclination angle γ were set to 25 degrees. The side where the columnar protrusion 1a is inclined is defined as the panel lower side. However, in FIG. 11 as well, although the gap between the adjacent protrusions 1a is illustrated to be large, the protrusions 1a are arranged so that the actual gap is narrower.

Similar to the first embodiment, FIG. 12 shows the result of measurement of the reflection characteristics of the reflection plate 1 having the column-shaped protrusions 1a of the fourth embodiment.

From FIGS. 12A and 12B, the reflecting plate 1 is
It can be seen that the reflection intensity R of the incident light not only from above the panel but also obliquely above and laterally increases.

FIG. 13 shows a columnar protrusion 1a according to the fourth embodiment.
1 shows a reflection type liquid crystal display panel manufactured by using the reflection plate 1 having the. In the liquid crystal display panel of FIG. 13, the reflector 1 is provided outside the panel of the glass substrate 2 which is the rear side (lower side in FIG. 13) in the used state. At this time, the pillar-shaped protrusion 1a is provided so as to be gently inclined obliquely downward from the base surface to the panel in the use state. Further, the pixel electrode 10 and the TFT element 9 are provided inside the panel of the glass substrate 2, and the counter electrode 11 is provided inside the panel of the glass substrate 2 which is the front side (upper side in FIG. 13) in use. Since the configuration is similar to that of Example 1, detailed description thereof will be omitted.

The voltage-reflectance characteristics of the reflection type liquid crystal display panel of FIG. 13 were measured according to the method of Example 1 and the results are shown in FIG.
4 shows. The reflectance Rf for incident light from above the panel, obliquely above, and the lateral direction reached about 50% to 20%, and the contrast was 10 to 15.

When the liquid crystal display panel provided with the reflector 1 was observed under normal illumination, the screen was very bright.
The contrast was also high.

As described above, the columnar protrusion 1a according to the fourth embodiment is used.
By using the reflector 1 having
It is possible to provide a bright reflective liquid crystal display panel by efficiently reflecting incident light from diagonally upper and lateral directions to the front of the panel.

(Embodiment 5) FIGS. 15A and 15B show a reflector 1 according to Embodiment 5, which is in the shape of a horizontally long ellipse. This reflection plate 1 is formed by brushing the surface of a metal film made of Al, Ni, Ag or the like with a polishing cloth having fused alumina abrasive grains adhered thereto in a horizontal direction with a 0.8 mm indentation of the polishing cloth, and stacking them vertically. Push the polishing cloth in the direction of 0.4 m
By brushing with m, a large number of minute horizontally elongated elliptical protrusions 1a are formed on the surface. The average shape of the laterally elliptical projection 1a is the diameter D3 3 in the direction of the ellipse major axis.
0 μm, ellipse minor axis diameter D4 is 10 μm, and height H is 2
μm. The apex of the protrusion 1a is ubiquitous in the lower part of the panel in use, and both upper and lower surfaces thereof are inclined, and the inclination angle α of the inclined surface on the upper side of the panel in use is the inclination of the inclined surface on the lower side of the panel. The angle is smaller than the angle β, and the inclined surface on the upper side of the panel is inclined more gently than the inclined surface on the lower side of the panel. That is, the apex of the protrusion 1a is formed in a portion close to the center of the gentle arc of the ellipse, and is inclined while gradually drawing a curved surface toward the other arc.
The side of the arc where the inclination angle of the protrusion 1a is gentle was defined as the upper side of the panel. However, in FIG. 15 as well, the gap between the adjacent protrusions 1a is illustrated to be large, but the protrusions 1a are arranged so that the actual gap is narrower.

The reflection characteristics of the reflector were measured in the same manner as in Example 1.

The reflection characteristic of the reflection plate 1 having the horizontally long elliptical projection 1a of Example 5 is the same as that shown in FIG.
It is understood that the reflection intensity R of incident light from not only above the panel but also obliquely above and in the lateral direction is high.

FIG. 16 shows a reflection type liquid crystal display panel manufactured by using the reflection plate 1 having the horizontally long elliptical projection 1a of the fifth embodiment. In the liquid crystal display panel of FIG. 16, the reflection plate 1 is provided outside the panel of the glass substrate 2, which is the rear side (lower side in FIG. 16) in the used state. That is, the reflective plate 1 also serving as a pixel electrode and the TFT element 9 are provided inside the panel of the glass substrate 2. At this time, the reflection plate 1 is provided so that the sloping surface of the protrusion 1a on the gentler side faces the upper side of the panel. Since the counter electrode 11 is provided inside the panel of the glass substrate 2 which is the front side (the upper side in FIG. 16) in the use state, the configuration is the same as that of the first embodiment, and thus the detailed description thereof is omitted.

When the voltage-reflectance characteristic of the reflection type liquid crystal display panel of FIG. 16 was measured according to the method of Example 1, the reflectance Rf for incident light from above the panel, diagonally above and lateral direction was the same as in FIG. Reached about 50% to 20%, and the contrast was 10 to 15.

When the liquid crystal display panel provided with the reflector 1 was observed under normal illumination, the screen was very bright and the contrast was high.

As described above, by using the reflection plate 1 having the horizontally long elliptical projection 1a of Example 5, incident light from above the panel, obliquely above, and from the lateral direction is efficiently reflected to the front surface of the panel and is bright. A reflective liquid crystal display panel can be provided.

(Embodiment 6) FIGS. 17A and 17B show a reflector 1 according to Embodiment 6, and the projection 1a of this reflector 1 has a horizontally long elliptical shape. This reflector is made by stretching an Al metal foil in one axial direction at a tensile strength of 10 kg / mm ² .
Furthermore, the tensile strength in the axial direction perpendicular to the axial direction is 7.6 kg.
A large number of minute laterally elliptical projections 1a are formed on the surface by stretching at a rate of / mm ² . In the case of a metal foil such as Ni or Ag, the stretching conditions are set according to the tensile strength of each metal. As for the average shape of the horizontally long elliptical projections 1a, the diameter D5 in the major axis direction of the ellipse was 30 μm, the diameter D6 in the minor axis direction of the ellipse was 20 μm, and the height H was 2 μm. The peripheral surface of the protrusion 1a of the reflector 1 obtained by this biaxial stretching is gently inclined with the central portion as the apex. That is, the apex of the protrusion 1a is formed in a portion close to the center and is inclined while gently drawing a curved surface toward the arc. The minor axis of the ellipse was defined as the vertical direction of the panel. However, in FIG. 17 as well, although the gap between the adjacent protrusions 1a is illustrated to be large, the protrusions 1a are arranged so that the actual gap becomes narrower.

The reflection characteristics of the reflector were measured in the same manner as in Example 1.

FIG. 18 shows a laterally elliptical protrusion 1 according to the seventh embodiment.
The reflection characteristic of the reflection plate 1 having a is shown. FIG. 18 (a),
From (b), in the present reflector 1, since the inclination angle of the elliptical projection 1a changes gently, the proportion of light reflected at a large angle and not reaching the outside of the cell is reduced, and the reflectance Rf of the panel is improved.

FIG. 19 shows a reflection type liquid crystal display panel manufactured in the same manner as in Example 5 using the reflection plate 1 having the oblong elliptical protrusions 1a of Example 7. In the liquid crystal display panel of FIG. 19, the reflection plate 1 also serving as the pixel electrode and the TFT element 9 are provided inside the panel of the glass substrate 2 which is the rear side (lower side of FIG. 19) in the used state, and the front side (upper side of the FIG. 19) in the used state. Since the counter electrode 11 is provided on the inside of the panel of the glass substrate 2), the configuration is similar to that of the first embodiment, and the detailed description thereof is omitted.

FIG. 20 shows the result of measurement of the voltage-reflectance characteristic of the reflection type liquid crystal display panel of FIG. 19 according to the method of Example 1. From FIG. 20, the reflectance Rf for incident light from the vertical direction of the panel reached about 40%, and the contrast was 10 to 15.

When the liquid crystal display panel provided with the reflector 1 was observed under normal illumination, the screen was very bright.
The contrast was also high.

As described above, by using the reflection plate 1 having the horizontally long elliptical projection 1a of Example 7, incident light from the vertical direction of the panel is efficiently reflected to the front surface of the panel,
A bright reflective liquid crystal display panel can be provided.

(Comparative Example) In this comparative example, the case where the metal foil surface of the reflection plate 1 is provided with irregularities to make the light reflection non-directional will be described.

FIGS. 21A and 21B show a reflector 1 of the comparative example.
The projection 1a of the reflection plate 1 has a perfect circular shape. The reflection plate 1 is formed by contacting a surface having a thin film formed by vapor-depositing a metal such as Al, Ni, or Ag with a roll having an irregularly arranged concave-convex structure and shaping. The diameter D7 of the protrusion 1a after shaping is 25 μm, and the height H is 2
μm, the apex of the protrusion 1a is formed in a portion close to the center of the protrusion 1a, and is inclined toward the surroundings while gently drawing a curved surface.

The reflection characteristics of the reflector 1 of this comparative example were measured in the same manner as in Example 1.

FIG. 22 shows the reflection characteristics of the reflector 1 having the protrusion 1a of this comparative example.

From FIGS. 22A and 22B, the reflector 1
Indicates that the incident light from all directions of the panel is scattered and the reflection intensity on the front surface of the panel is low.

As in Example 1, the measurement result of the voltage-reflectance characteristic of the reflection type liquid crystal display panel manufactured by using the reflection plate 1 in which the protrusions 1a having a perfect circle shape are irregularly arranged on the surface is shown in FIG.
3 is shown.

From FIG. 23, the reflectance Rf for the incident light from each direction reached only about 25%, and the contrast was 8 to 13.

When the liquid crystal display panel provided with the reflection plate 1 of this comparative example was observed under normal illumination, the screen as a whole was dark and the contrast was low.

[0087]

As described above, according to the present invention as set forth in claim 1, since the projection on the surface of the reflector plate is gently inclined to the upper side of the panel when in use, the reflection area of the panel is widened. More external light from the direction can be reflected on the front surface of the panel.

According to the second aspect of the present invention, the stripe-shaped protrusions allow external light from above the panel to be directed to the front of the panel by the gently inclined surface on the panel upper side of the protrusions formed on the reflector surface. It can be reflected efficiently.

According to the present invention as set forth in claims 3 to 5, the external light from the panel upward direction and the lateral direction is formed on the surface of the reflection plate by the substantially fan-shaped, perfectly circular, and oblong elliptical projections. The gentle slopes on the upper and lateral sides of the panel of the protrusion allow efficient reflection on the front of the panel.

According to the sixth aspect of the present invention, since a large number of fine columnar projections formed on the surface of the reflection plate are gently formed obliquely downward in the panel in the use state, the panel is directed upward and laterally. It is possible to efficiently reflect outside light from the front of the panel.

According to the seventh aspect of the present invention, since a large number of fine projections formed on the surface of the reflection plate are formed in a horizontally elongated elliptical shape with the center part as the apex and the peripheral surface being gently inclined, Incident light from any direction can be efficiently reflected to the front surface of the panel.

According to the present invention of claim 8, the fine projections on the surface of the metal film are brushed in two directions, and
Since the second brushing is weakened, it is possible to form the inclination angle of the elliptical projection on the panel upper side and the lateral side more gently than the inclination angle of the panel lower side. External light from the lateral direction can be efficiently reflected.

According to the present invention of claim 9, the metal is obliquely vapor-deposited from below toward the base, whereby a large number of fine columnar projections are projected obliquely downward from the base surface. Such a reflector can be easily obtained.

According to the tenth aspect of the present invention, since the fine protrusions on the surface of the reflecting plate are formed into an elliptical shape by biaxially stretching the metal foil, the inclination angle can be made gentle, and the vertical direction of the panel. The incident light from can be efficiently reflected to the front of the panel.

According to the present invention of claims 11 and 12,
By using the reflection plate as described above, incident light from above the panel, obliquely above or laterally can be efficiently reflected to the front of the panel, and a bright reflective liquid crystal display panel can be obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a reflection plate according to a first embodiment.

FIG. 2 is an explanatory diagram showing a method for measuring the reflection characteristic of a reflection plate in Example 1.

FIG. 3 is a characteristic diagram showing a reflection characteristic of a reflection plate in Example 1.

FIG. 4 is a configuration diagram of a reflective liquid crystal display panel in Example 1.

5 is a characteristic diagram showing voltage-reflectance characteristics of the reflective liquid crystal display panel in Example 1. FIG.

FIG. 6 is a configuration diagram of a reflecting plate according to a second embodiment.

FIG. 7 is a characteristic diagram showing a reflection characteristic of a reflection plate in Example 2.

FIG. 8 is a characteristic diagram showing a voltage-reflectance characteristic of the reflective liquid crystal display panel in Example 2.

FIG. 9 is a configuration diagram of a reflection plate in Example 3.

FIG. 10 is a configuration diagram of a reflective liquid crystal display panel in Example 3.

FIG. 11 is a configuration diagram of a reflection plate in Example 4.

FIG. 12 is a characteristic diagram showing a reflection characteristic of a reflection plate in Example 4.

FIG. 13 is a configuration diagram of a reflective liquid crystal display panel in Example 4.

14 is a characteristic diagram showing voltage-reflectance characteristics of the reflective liquid crystal display panel in Example 4. FIG.

FIG. 15 is a configuration diagram of a reflector in Example 5.

FIG. 16 is a configuration diagram of a reflective liquid crystal display panel in Example 5.

FIG. 17 is a configuration diagram of a reflecting plate in the sixth embodiment.

FIG. 18 is a characteristic diagram showing a reflection characteristic of a reflection plate in Example 6.

FIG. 19 is a configuration diagram of a reflective liquid crystal display panel in Example 6.

FIG. 20 is a characteristic diagram showing voltage-reflectance characteristics of the reflective liquid crystal display panel in Example 6.

FIG. 21 is a configuration diagram of a reflector in a comparative example.

FIG. 22 is a characteristic diagram showing a reflection characteristic of a reflector in a comparative example.

FIG. 23 is a characteristic diagram showing voltage-reflectance characteristics of a reflective liquid crystal display panel in a comparative example.

[Explanation of symbols]

1 Reflector 1a Projection 1b Base 2 Substrate 5 Liquid crystal 10 and 11 Electrode α Inclination angle of the inclined surface of the protrusion that is the upper side of the panel in the used state β Inclination angle of the inclined surface of the protrusion that is the lower side of the panel in the used state γ Columnar protrusion Tilt angle

Claims (12)

[Claims] 1. The reflection plate of a reflection type liquid crystal display panel, wherein a liquid crystal is interposed between a pair of front and rear substrates provided with electrodes, and a reflection plate is attached to the inside or outside of the panel of the rear substrate, the surface being the reflection plate. Has a large number of minute projections, the apex of these projections is ubiquitous in the lower part of the panel in use, and its side surface is inclined. A reflecting plate characterized in that it is smaller than the inclination angle of the inclined surface that is the side, and the inclined surface that is the upper side of the panel is more gently inclined than the inclined surface that is the lower side of the panel. 2. The projection has a striped shape extending in parallel to the left and right sides of the panel when in use.
Reflector as described. 3. The reflector according to claim 1, wherein the protrusion has a substantially fan shape. 4. The reflector according to claim 1, wherein the protrusion has a perfect circular shape. 5. The reflector according to claim 1, wherein the projection has a horizontally long elliptical shape. 6. The reflection plate of a reflection type liquid crystal display panel, wherein liquid crystal is interposed between a pair of front and rear substrates provided with electrodes, and a reflection plate is attached inside or outside the panel of the rear substrate, wherein A reflector having a large number of fine protrusions, which are columnar in shape, and are gently inclined obliquely downward from the base surface to the panel in use. 7. The reflection plate of a reflection type liquid crystal display panel, wherein a liquid crystal is interposed between a pair of front and rear substrates provided with electrodes, and a reflection plate is attached inside or outside the panel of the rear substrate, the surface comprising A reflector having a large number of minute projections, which are oblong elliptical in shape, and whose peripheral surface is gently inclined with the central portion as the apex. 8. The method of manufacturing a reflector according to claim 5, wherein the surface of the metal film is brushed in a direction that is the horizontal direction of the panel when in use, and then the surface is a direction that is the vertical direction of the panel in use. By weakening and brushing, the metal film surface has a large number of minute oblong elliptical protrusions. The inclined angle of the inclined surface on the upper side of the panel is smaller than the inclined angle of the inclined surface on the lower side of the panel in use, and the inclined surface on the upper side of the panel is inclined more gently than the inclined surface of the lower side of the panel. A method for producing a reflector, which comprises obtaining the reflector. 9. The method of manufacturing a reflection plate according to claim 6, wherein a large number of fine columnar projections are used from the base surface in an in-use state by obliquely depositing metal from below toward the base. A method of manufacturing a reflection plate, characterized in that a reflection plate gently inclined downwardly of the panel is obtained. 10. The method for manufacturing a reflection plate according to claim 7, wherein the metal foil is stretched biaxially to have a large number of minute oblong elliptical protrusions on the surface. A method of manufacturing a reflector, characterized in that a reflector whose peripheral surface is gently inclined with the central portion as an apex is obtained. 11. A liquid crystal is interposed between a pair of front and rear substrates provided with electrodes, and the reflection plate according to claim 1 is attached to the rear substrate outside the panel. A reflection type liquid crystal display panel using a reflector. 12. A liquid crystal is interposed between a pair of front and rear substrates provided with electrodes, and the reflector according to claim 1 is attached to the inside of the panel of the rear substrate. A reflective liquid crystal display panel using a reflector, which has a function as an electrode.