JP2845783B2 - REFLECTIVE PLATE, METHOD OF MANUFACTURING THE SAME, AND REFLECTIVE LIQUID CRYSTAL DISPLAY PANEL USING THE REFLECTIVE PLATE - Google Patents

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 of manufacturing the same, and an improvement of a reflection type liquid crystal display panel using the reflection plate.

[0002]

2. Description of the Related Art Recently, liquid crystal display panels have been applied to word processors, laptop computers, car navigation systems, etc., taking advantage of the features of thinness, light weight, and low power consumption. In particular, since a reflective liquid crystal display panel using external light does not require a backlight, it is possible to significantly reduce power consumption and further reduce the thickness and weight. The display modes of such a reflective liquid crystal display panel include a twisted nematic (TN) system requiring a polarizing plate and a super twisted nematic (STN) system, a guest-host system requiring no polarizing plate, and a polymer dispersion system. .

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 to increase the reflection luminance. In a mode requiring a polarizing plate, there is an advantage that black can be surely produced by aligning the polarization axes, but the reflected light is の of the incident light. on the other hand,
In the mode in which the polarizing plate is not required, the contrast is slightly low, but the reflection luminance is high.

In a reflection type liquid crystal display panel, it is essential to improve the reflection characteristics of a reflection plate. As a method of improving the reflection characteristics of the reflection plate, in order to make it easier to read the liquid crystal display from any angle, an uneven roll is brought into contact with the metal foil surface to form the unevenness, and the light reflection on the metal foil surface is reduced. A method of making a non-directional (JP-A-3-246502) or a method of obtaining a high diffuse reflectance optically non-directional by stretching a matte aluminum alloy foil in a uniaxial direction (Japanese Patent Laid-Open No. 64-246) No. 66687).

[0005] An example of a reflection characteristic having directivity is a saw-tooth shape in which the viewing surface is inclined so that the perpendicular to the reflecting surface of the reflector and the perpendicular to the front surface of the panel intersect at a certain angle. (Japanese Unexamined Patent Publication No.
1-270731) has been proposed.

[0006]

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

However, in the above-mentioned conventional method of making the light reflection on the surface of the metal foil non-directional, a method of scattering the light reflected from the reflector as much as possible is employed, so that the panel reflection luminance in front of the user is low. turn into.

Further, in the method of making the surface of the reflector a saw-tooth shape in which the viewing angle direction is inclined, light is reflected with directivity, but the viewing angle range in which high brightness is obtained is very narrow.
External light from above the panel is effectively reflected, but external light from obliquely above and from the side cannot be used.

In the method of stretching the metal foil in a uniaxial direction, a large number of very elongated elliptical projections having a major 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 vertex. However, in the direction perpendicular to the axis, the inclination angle of the elliptical projection changes rapidly, and light reflected at a large angle is reflected at the interface between glass and air and cannot reach the outside of the cell, so that the reflection intensity sharply decreases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a reflective plate having good visibility and directivity, a method of manufacturing the same, and a reflective liquid crystal display using the reflective plate. Is to provide a panel.

[0011]

In order to achieve the above object, the present invention has variously modified the shape of a projection formed on a reflection plate. Taken.

That is, the first to seventh solutions of the present invention are directed to a reflection type in which a liquid crystal is interposed between a pair of front and rear substrates provided with electrodes, and a reflection plate is provided inside or outside the panel of the rear substrate. The present invention relates to the reflection plate of the liquid crystal display panel, and the first solution is to have a large number of fine projections on the surface as the reflection plate. At this time, the apex of this projection is ubiquitously located below the panel in use and the side thereof is inclined, and the angle of inclination of the upper surface of the panel in use is greater than the angle of inclination of the lower surface of the panel in use. It is characterized in that the inclined surface on the upper side of the panel is more gently inclined than the inclined surface on the lower side of the panel.

According to a second aspect of the present invention, in the first aspect, the projection is formed in a stripe shape extending parallel to the left and right sides of the panel in use.

According to a third aspect of the present invention, in the first aspect of the present invention, the projecting portion has a substantially sector shape.

According to a fourth aspect of the present invention, in the first aspect, the projection is formed in a perfect circle.

According to a fifth aspect of the present invention, in the first aspect, the protruding portion is formed in a horizontally long elliptical shape.

According to a sixth aspect of the present invention, as described above, it is assumed that the reflecting plate has a large number of fine projections on its surface. In this case, the projection is formed in a columnar shape, and is gently tilted obliquely downward from the base surface to the panel in use.

According to a seventh solution, on the premise as described above, it is assumed that the reflector has a large number of fine projections on its surface. At this time, the protrusion is formed in a horizontally long elliptical shape, and the peripheral surface is gently inclined with the central portion as the vertex.

Eighth to tenth solutions of the present invention relate to a method of manufacturing the above-mentioned reflector. The eighth solution relates to the manufacturing method of the reflection plate according to the fifth solution, and firstly, the surface of the metal film is brushed in the horizontal direction of the panel in use. Thereafter, the surface of the metal film is brushed with reduced strength in the direction of the panel up and down direction in use, so that the metal film surface has a number of fine horizontally long elliptical protrusions, and the apex of this protrusion is In use, the panel is ubiquitous below the panel and its side surfaces are inclined. In use, the angle of inclination of the upper surface of the panel is smaller than the angle of inclination of the lower surface of the panel, and the upper surface of the panel is inclined. The present invention is characterized in that a reflecting plate is obtained in which the inclined surface is more gradually inclined than the inclined surface below the panel.

A ninth solution of the present invention relates to a method of manufacturing a reflector according to the sixth solution, wherein a plurality of fine columnar shapes are formed by obliquely depositing metal from below toward a base. Is characterized in that a reflection plate whose projection is gently inclined obliquely downward from the base surface to the panel is obtained.

According to a tenth aspect of the present invention, there is provided a method of manufacturing a reflector according to the seventh aspect, wherein a metal foil is biaxially stretched to form a plurality of fine oblong shapes on the surface. The reflector is characterized in that a reflecting plate whose peripheral surface is gently inclined with the central portion as the apex is obtained.

The eleventh and twelfth solutions of the present invention relate to a reflection type liquid crystal display panel using the above-mentioned reflection plate. The LCD is interposed. Further, the reflection plate of any one of the first to seventh solving means is provided outside the panel of the rear substrate.

According to a twelfth solution, a liquid crystal is interposed between a pair of front and rear substrates provided with electrodes. Further, the reflection plate of any one of the first to seventh solving means is provided inside the panel of the rear substrate. In this case, the reflection plate also has a function as an electrode.

With the above arrangement, the first to twelfth means of the present invention have the following functions and effects. Before describing the state of use, the reflective liquid crystal display panel displays an image by reflecting external light with a reflector. In most cases, the external light source is the sun outdoors and the ceiling light indoors, and these are located above or laterally above the panel. It is considered that there is very little external light source below the panel, so it can be said that the structure that captures external light from the top and side of the panel to the maximum and reflects it to the front of the panel has the best reflection efficiency. .

Therefore, in the first solution of the present invention, the inclination of the inclined surface on the upper side of the panel is gentle in the use state of a large number of fine projections formed on the surface of the reflection plate, so that The reflection area on the upper side is widened, and more external light from above the panel is reflected to the front of the panel.

According to the second solution of the present invention, the stripe shape of the projection allows the external light from above the panel to be efficiently directed to the front of the panel by the gentle slope of the projection above the panel formed on the reflector surface. Reflects well.

According to the third to fifth solutions of the present invention, the external light from the panel upward and lateral directions is formed on the surface of the reflecting plate by the substantially fan shape, the perfect circular shape and the horizontally long elliptical shape of the projection. The light is efficiently reflected to the front of the panel by the gentle slopes on the upper side and the side of the panel.

According to the sixth solution of the present invention, since a large number of fine columnar projections projecting from the base surface are gently inclined obliquely downward to the panel in use, the upward and lateral directions of the panel are improved. External light is efficiently reflected to the front of the panel.

According to the seventh solution of the present invention, a large number of fine projections formed on the surface of the reflection plate have a horizontally long elliptical shape in which the peripheral surface is gently inclined with the central portion as the top.
Incident light from the vertical direction of the panel is efficiently reflected to the front of the panel.

According to an eighth solution of the present invention, first, a first elliptical protrusion having a major axis in the lateral direction is obtained by brushing on the surface of the metal film, and then the elliptical protrusion is formed by weak brushing. The inclination angles on the upper side and the lateral side of the panel become gentler than the inclination angles on the lower side of the panel, and the oblong shape of the fifth solving means is obtained. Therefore, external light from the upper and lateral directions of the panel is efficiently reflected on the front of the panel by the gentle slopes on the upper and lateral sides of the projection formed on the surface of the reflector.

According to the ninth solution of the present invention, when metal is obliquely deposited from below toward the base, a large number of fine columnar projections project obliquely downward from the base surface, and the sixth aspect of the present invention provides a method for manufacturing a semiconductor device. The reflector of the solution is easily obtained.

According to a tenth solution of the present invention, the fine projection on the surface of the reflector has 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 protruding shape is obtained, which is further extended in the other axial direction (for example, longitudinal direction) to obtain a nearly circular elliptical protruding shape. It becomes an elliptical shape. As described above, since the inclination angle of the elliptical projection gradually changes by extending in the biaxial direction, the ratio of light reflected at a large angle and not reaching the outside of the cell decreases. Therefore, the reflection characteristic of this reflector is
If the angle is increased along the axial direction starting from the angle at which the reflection intensity is the largest in both the horizontal and vertical directions, the change in the reflection intensity will not be abrupt.

According to the eleventh and twelfth solutions of the present invention, incident light from above the panel, obliquely above, or from the horizontal direction is efficiently reflected toward the front of the panel due to the reflection characteristics of the reflector described above, and a bright reflective type is used. A liquid crystal display panel is 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. As shown in FIG.
The reflector 1 is provided on the inner surface of the glass substrate 2 behind the reflective liquid crystal display panel. A large number of fine stripe-shaped protrusions 1a are formed on the surface of the reflection plate 1, and the protrusions 1a are arranged so as to extend in parallel to the panel left and right in use. The top of the projection 1a is ubiquitous below the panel in use, and the upper and lower sides of the projection 1a are inclined. In use, the inclination angle α of the upper surface of the panel is lower than the lower surface of the panel. Is smaller than the inclination angle β, and the inclined surface on the upper side of the panel is more gradually inclined than the inclined surface on the lower side of the panel. This reflector 1
It is formed by bringing a roll having a striped uneven structure into contact with a surface on which a thin film is formed by vapor-depositing a metal such as Al, Ni, or Ag, and shaping the roll. The width W1 of the strip-shaped protrusion 1a after shaping is 15 μm, the height H is 2 μm,
The interval W2 between the adjacent projections 1a is 5 μm, and the side of the projection 1a where the inclination is gentle is the upper side of the panel.

FIG. 2 shows a method for measuring the reflection characteristics of the reflector 1. The model of the reflective panel used for this measurement is manufactured by bonding a dummy glass having substantially the same refractive index as the liquid crystal on the reflecting plate 1 with an ultraviolet curable resin also having the same refractive index.
The model of the reflection type panel is set horizontally as a measurement target 7, light is incident from the incident light source 4 at an angle θ and a rotation angle に 対 し て with respect to the normal, and the reflection intensity R in the front direction is measured by the photomultimeter 3. did.

FIG. 3 shows the reflection characteristics of the reflector 1 of the first embodiment. FIG. 3A shows the measurement system shown in FIG.
固定, 90 ゜, 180 ゜, 225 ゜, and 270 そ れ ぞ れ, respectively, and the reflection intensity R on the front surface of the reflector 1 when the incident angle θ is changed is represented by the distance from the origin O. FIG. 3B shows the reflection intensity R when the incident angle θ is fixed to 30 ° and the rotation angle ψ is increased in the measurement system of FIG.

As shown in 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 using the reflection plate 1 having the stripe-shaped projections 1a. The reflection type liquid crystal display panel includes a pair of front and rear glass substrates 2, and a pixel electrode 10 and each pixel are provided inside the glass substrate (active matrix substrate) 2 which is located forward (upper side in FIG. 4) in use. A thin film transistor (hereinafter referred to as a TFT element) 9 is disposed on the inner side of the panel of the glass substrate 2 which is rearward (lower side in FIG. 4) in use. The liquid crystal 5 and the spacer 8 are interposed between the two glass substrates 2. When the liquid crystal 5 is sealed, first, an alignment film is applied on both glass substrates 2, and a particle diameter of 6 μm is formed between the two glass substrates 2.
m spacers 8 are scattered, a sealant is printed on the periphery, and then bonded. 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 using the measurement system shown in FIG. 2 by arranging the glass substrate 2 on the side provided with the reflection plate 1 as a lower substrate. The reflectance Rf was determined from 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 when the incident angle θ = 30 °.

FIG. 5 shows that the reflectance Rf with respect to incident light from above the panel reached about 50%, and the contrast was 10 to 15.

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

As described above, by using the reflector 1 having the stripe-shaped projections 1a of Embodiment 1, incident light from above the panel is efficiently reflected toward the front of the panel, and a bright reflective 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 has a fan shape. This reflector is made of Al, N
It is formed by bringing a roll having a fan-shaped uneven structure into contact with a surface on which a thin film is formed by evaporating a metal such as i, Ag or the like and shaping the roll. Fan-shaped protrusion 1 after shaping
a has a width W3 of 25 μm in the horizontal direction and a width W4 of 15 in the vertical direction.
μm, and the height H was 2 μm. The apex of the projection 1a is ubiquitous below the panel in use, and the upper and lower sides are inclined. In use, the inclination angle α of the upper surface of the panel is equal to the inclination angle of the lower surface of the panel. Is smaller than the angle β, and the inclined surface on the upper side of the panel is more gently inclined than the inclined surface on the lower side of the panel. That is, the apex of the protruding portion 1a is formed at a portion near the central angle of the fan shape, and the side surface is inclined while gradually drawing a curved surface toward the arc of the fan shape. The side of the arc where the inclination angle of the protrusion 1a is gentle is set to the upper side of the panel in use. However, in FIG. 6, the distance between the adjacent protrusions 1 a is large, but the protrusions 1 a are arranged so that the actual distance is narrower.

FIG. 7 shows the result of measuring the reflection characteristics of the reflector 1 having the fan-shaped projection 1a of the second embodiment, as in the first embodiment.

As shown in FIGS. 7A and 7B, the reflector 1 is
It can be seen that the reflection intensity R of the incident light from not only above the panel but also obliquely above and from the lateral direction is large.

FIG. 8 shows the measurement results of the voltage-reflectance characteristics of the reflective liquid crystal display panel manufactured using the reflector 1 having the fan-shaped projection 1a of the second embodiment, as in the first embodiment. .

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

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

As described above, by using the reflecting plate 1 having the fan-shaped protrusion 1a of the second embodiment, incident light from above the panel, obliquely above and from the lateral direction is efficiently reflected toward 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 a third embodiment. In the third embodiment, a projection 1a is provided.
Has a perfect circular shape. This reflecting plate 1 is made of Al, Ni,
It is formed by bringing a roll having a circular concavo-convex structure into contact with the surface of a thin film formed by evaporating a metal such as Ag on the base 1b and shaping the thin film. The diameter D1 of the circular protrusion 1a after shaping was 15 μm, and the height H was 2 μm. The apex of the projection 1a is ubiquitous below the panel in use, and the upper and lower sides are inclined. In use, the inclination angle α of the upper surface of the panel is equal to the inclination angle of the lower surface of the panel. Is smaller than the angle β, and the inclined surface on the upper side of the panel is more gently inclined than the inclined surface on the lower side of the panel. That is, the apex of the protrusion 1a is formed at a portion near a part of the arc from the center of the circle, and is inclined while gradually drawing a curved surface toward the arc. The side of the arc where the inclination angle of the projection 1a is gentle is the upper side of the panel in use. However,
In FIG. 9 as well, the distance between the adjacent protrusions 1a is large, but the protrusions 1a are arranged so that the actual distance becomes smaller.

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

The reflection characteristics of the reflector 1 having the circular protrusion 1a of the third embodiment are the same as those shown in FIG.
It can be seen that the reflection intensity R of the incident light from not only above the panel but also obliquely above and from the lateral direction is large.

FIG. 10 shows the circular projection 1 of the third embodiment.
1 shows a reflective liquid crystal display panel manufactured using a reflector 1 having a. In the liquid crystal display panel of FIG. 10, a gentle slope of the projection 1a is provided on the outside of the panel of the glass substrate 2 which is rearward (the lower side in FIG. 10) of the reflection plate 1 in use. Except that the counter electrode 11 is provided inside the panel of the glass substrate 2, the configuration is the same as that of the first embodiment, and a detailed description thereof will be omitted.

When the voltage-reflectance characteristics of the reflection type liquid crystal display panel of FIG. 10 were measured in accordance with the method of Example 1, the reflectance Rf for incident light from above the panel, obliquely above, and from the side was obtained in the same manner as in FIG. Reached about 50% to 20%, and the contrast was 10 to 15.

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

As described above, the perfectly circular protrusion 1a of the third embodiment is used.
By using the reflection plate 1 having
Incident light from obliquely upward and lateral directions is efficiently reflected toward the front of the panel, and a bright reflective liquid crystal display panel can be provided.

Fourth Embodiment FIGS. 11A and 11B show a reflector 1 according to a fourth embodiment, and the projection 1a of the reflector 1 has a columnar shape. This reflector 1 is made of Al, Ni, A
g or the like is formed on the base 1b by rotary oblique evaporation in an 80-degree system to form a large number of fine columnar projections 1a on the surface. The columnar projections 1a are used from the base surface in use. The panel is gently inclined diagonally downward. The diameter D2 of the columnar protrusion 1a is 0.2 μm, and the length L is 1 μm.
m and the inclination angle γ were 25 degrees. The inclined side of the columnar projection 1a was defined as the lower side of the panel. However, in FIG. 11 as well, the distance between the adjacent protrusions 1a is large, but the protrusions 1a are arranged so that the actual distance is narrower.

FIG. 12 shows the result of measurement of the reflection characteristics of the reflector 1 having the columnar protrusions 1a of the fourth embodiment, as in the first embodiment.

As shown in FIGS. 12A and 12B, the reflector 1 is
It can be seen that the reflection intensity R of the incident light from not only above the panel but also obliquely above and from the lateral direction is large.

FIG. 13 shows a columnar projection 1a according to the fourth embodiment.
1 shows a reflection type liquid crystal display panel manufactured using a reflection plate 1 having: In the liquid crystal display panel of FIG. 13, the reflection plate 1 is provided outside the panel of the glass substrate 2 which is rearward (the lower side in FIG. 13) in use. At this time, the columnar projection 1a is provided so as to be gently inclined obliquely downward from the base surface to the panel in use. 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 forward (upper side in FIG. 13) in use. Since the configuration is the same as that of Example 1, the detailed description is omitted.

FIG. 1 shows the result of measuring the voltage-reflectance characteristics of the reflection type liquid crystal display panel of FIG. 13 according to the method of the first embodiment.
It is shown in FIG. The reflectance Rf for incident light from above the panel, obliquely above and from the lateral direction reached about 50% to 20%, and the contrast was 10 to 15.

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

As described above, the columnar projection 1a of the fourth embodiment
By using the reflection plate 1 having
Incident light from obliquely upward and lateral directions is efficiently reflected toward the front of the panel, and a bright reflective liquid crystal display panel can be provided.

Fifth Embodiment FIGS. 15A and 15B show a reflector 1 according to a fifth embodiment, and the reflector 1 has a horizontally long elliptical shape. The reflection plate 1 is formed by brushing the surface of a metal film such as Al, Ni, Ag or the like with a polishing cloth to which abrasive grains of fused alumina are adhered by pushing the polishing cloth in a horizontal direction at 0.8 mm, and stacking the layers vertically. 0.4m of polishing cloth in the direction
By brushing with m, many fine horizontally long elliptical protrusions 1a are formed on the surface. The average shape of the horizontally long elliptical protrusion 1a is a diameter D33 in the direction of the major axis of the ellipse.
0 μm, the diameter D4 in the minor axis direction of the ellipse is 10 μm, and the height H is 2
μm. The apex of the projection 1a is ubiquitous below the panel in use, and the upper and lower sides are inclined. In use, the inclination angle α of the upper surface of the panel is equal to the inclination angle of the lower surface of the panel. Is smaller than the angle β, and the inclined surface on the upper side of the panel is more gently inclined than the inclined surface on the lower side of the panel. That is, the apex of the protrusion 1a is formed at a portion near 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 projection 1a is gentle is defined as the upper side of the panel. However, in FIG. 15 as well, the distance between the adjacent protrusions 1a is drawn large, but the protrusions 1a are arranged so that the actual distance is narrower.

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

The reflection characteristic of the reflector 1 having the horizontally long elliptical protrusion 1a of the fifth embodiment is the same as that of FIG.
It can be seen that the reflection intensity R of the incident light from not only above the panel but also obliquely above and from the lateral direction is large.

FIG. 16 shows a reflection type liquid crystal display panel manufactured using the reflection plate 1 having the horizontally long elliptical protrusion 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 rearward (lower side in FIG. 16) in use. That is, 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. At this time, the reflection plate 1 is provided such that the gentle inclined surface of the projection 1a faces the upper side of the panel. Except that the counter electrode 11 is provided inside the panel of the glass substrate 2 which is located forward (upper side in FIG. 16) in the use state, the configuration is the same as that of the first embodiment, so that the detailed description is omitted.

The voltage-reflectance characteristics of the reflection type liquid crystal display panel of FIG. 16 were measured in accordance with the method of Example 1. As in FIG. 8, the reflectance Rf for incident light from above the panel, obliquely above, and from the side was obtained. Reached about 50% to 20%, and the contrast was 10 to 15.

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

As described above, by using the reflecting plate 1 having the horizontally long elliptical projections 1a of the fifth embodiment, the incident light from above the panel, obliquely above and from the horizontal direction is efficiently reflected toward the front of the panel, and is bright. A reflective liquid crystal display panel can be provided.

Sixth Embodiment FIGS. 17A and 17B show a reflector 1 according to a sixth embodiment, and the projection 1a of the reflector 1 has a horizontally long elliptical shape. This reflector is obtained by stretching Al metal foil in one axial direction at a tensile strength of 10 kg / mm ² ,
Furthermore, a tensile strength of 7.6 kg in the axial direction perpendicular to the axial direction.
/ Mm ² to form a large number of fine oblong projections 1a on the surface. 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. The average shape of the horizontally long elliptical protrusion 1a was such that the diameter D5 in the long axis direction of the ellipse was 30 μm, the diameter D6 in the short axis direction of the ellipse was 20 μm, and the height H was 2 μm. The peripheral surface of the projection 1a of the reflector 1 obtained by this biaxial stretching is gently inclined with the central part as the top. That is, the apex of the protrusion 1a is formed in a portion near the center, and is inclined while gradually drawing a curved surface toward the arc. The elliptical minor axis direction was defined as the panel vertical direction. However, in FIG. 17 as well, the distance between the adjacent protrusions 1a is drawn large, but the protrusions 1a are arranged so that the actual distance becomes smaller.

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

FIG. 18 shows a horizontally elongated elliptical projection 1 according to the seventh embodiment.
4 shows the reflection characteristics of the reflector 1 having a. FIG. 18 (a),
From (b), in the present reflection plate 1, since the inclination angle of the elliptical projection 1a changes gradually, the ratio of the 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 horizontally long elliptical projections 1a of Example 7. In the liquid crystal display panel of FIG. 19, the reflector 1 serving also as a pixel electrode and the TFT element 9 are provided inside the panel of the glass substrate 2 which is rear (lower side in FIG. 19) in use, and front (upper in FIG. 19) in use. Since the configuration is the same as that of the first embodiment except that the counter electrode 11 is provided inside the panel of the glass substrate 2 to be described as), detailed description thereof is omitted.

FIG. 20 shows the result of measuring the voltage-reflectance characteristics of the reflection type liquid crystal display panel of FIG. 19 according to the method of Example 1. As shown in FIG. 20, the reflectance Rf with respect to the incident light from above and below the panel reached about 40%, and the contrast was 10 to 15.

When the liquid crystal display panel provided with the reflection plate 1 was observed with ordinary illumination, the screen was very bright.
The contrast was also high.

As described above, by using the reflector 1 having the horizontally long elliptical projection 1a of the seventh embodiment, the incident light from the vertical direction of the panel can be efficiently reflected to the front of the panel.
A bright reflective liquid crystal display panel can be provided.

(Comparative Example) This comparative example shows a case in which irregularities are formed on the surface of the metal foil of the reflecting plate 1 so that light reflection is made non-directional.

FIGS. 21A and 21B show the reflection plate 1 of the comparative example.
The projection 1a of the reflector 1 has a perfect circular shape. The reflecting plate 1 is formed by bringing a roll having an irregularly arranged uneven structure into contact with a surface on which a thin film is formed by evaporating a metal such as Al, Ni, and Ag, and forming the thin film. The diameter D7 of the protrusion 1a after the shaping is 25 μm, and the height H is 2 μm.
μm, the vertex of the protrusion 1a is formed at a portion near the center of the protrusion 1a, and is inclined while gradually drawing a curved surface toward the periphery.

As in Example 1, the reflection characteristics of the reflector 1 of this comparative example were measured.

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

As shown in FIGS. 22A and 22B, the present reflector 1
It can be seen that the scattered incident light from all directions of the panel lowers the reflection intensity in front of the panel.

As in Example 1, FIG. 2 shows the measurement results of the voltage-reflectance characteristics of the reflection type liquid crystal display panel manufactured by using the reflection plate 1 in which the perfect circular projections 1a are irregularly arranged on the surface.
3 is shown.

FIG. 23 shows that the reflectance Rf with respect to 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 with ordinary illumination, the screen was dark overall and the contrast was low.

[0087]

As described above, according to the first aspect of the present invention, the reflection area is widened by the gentle slope that is on the upper side of the panel when the projection on the surface of the reflector is used. More external light from the direction can be reflected to the front of the panel.

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

According to the third to fifth aspects of the present invention, the external light from the panel upper direction and the horizontal direction is formed on the surface of the reflection plate by the substantially fan-shaped, perfect circular, and horizontally long elliptical projections. The gently inclined surfaces on the upper side and the lateral side of the projection can efficiently reflect the light to the front of the panel.

According to the sixth aspect of the present invention, the inclination of a large number of fine columnar projections formed on the surface of the reflection plate is gently formed obliquely downward on the panel in use, so that the upward and horizontal directions of the panel can be obtained. External light can be efficiently reflected to the front of the panel.

According to the present invention, a large number of fine projections formed on the surface of the reflection plate are formed into a horizontally long elliptical shape in which the peripheral surface is gently inclined with the central portion as the apex. The incident light from the direction can be efficiently reflected to the front of the panel.

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

According to the ninth aspect of the present invention, a large number of fine columnar projections project obliquely downward from the base surface by depositing metal obliquely from below toward the base. Such a reflector can be easily obtained.

According to the tenth aspect of the present invention, since the fine projections on the surface of the reflector are formed in an elliptical shape by biaxially stretching the metal foil, the inclination angle can be made gentle and the vertical direction of the panel can be reduced. Incident light can be efficiently reflected to the front of the panel.

According to the eleventh and twelfth aspects of the present invention,
By using the above-described reflector, incident light from above the panel, obliquely above, or from the side can be efficiently reflected toward the front of the panel, and a bright reflective liquid crystal display panel can be obtained.

[Brief description of the 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 characteristics of the reflector in Example 1.

FIG. 3 is a characteristic diagram illustrating a reflection characteristic of the reflection plate according to the first embodiment.

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

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

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

FIG. 7 is a characteristic diagram showing reflection characteristics of a reflector 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 according to a third embodiment.

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

FIG. 11 is a configuration diagram of a reflection plate according to a fourth embodiment.

FIG. 12 is a characteristic diagram illustrating reflection characteristics of a reflector according to a fourth embodiment.

FIG. 13 is a configuration diagram of a reflective liquid crystal display panel according to a fourth embodiment.

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

FIG. 15 is a configuration diagram of a reflection plate according to a fifth embodiment.

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

FIG. 17 is a configuration diagram of a reflection plate according to a sixth embodiment.

FIG. 18 is a characteristic diagram showing reflection characteristics of the reflection plate according to the sixth embodiment.

FIG. 19 is a configuration diagram of a reflection type liquid crystal display panel in Embodiment 6.

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

FIG. 21 is a configuration diagram of a reflection plate in a comparative example.

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

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

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Reflector 1a Projection 1b Base 2 Substrate 5 Liquid crystal 10,11 Electrode α Incline angle of projecting inclined surface on the upper side of panel in use state β Inclined angle of projecting inclined surface on the lower side of panel in use state γ Columnar projection Angle of inclination

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-178626 (JP, A) JP-A-3-31782 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G02F 1/1335 520 G02B 5/08

Claims (12)

(57) [Claims] 1. 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 provided inside or outside the panel of the rear substrate. In use, the apex of the protrusion is ubiquitous under the panel and its side surface is inclined, and the inclination angle of the inclined surface that is on the upper side of the panel in use is lower than the panel. A reflection plate, wherein the inclination angle is smaller than the inclination angle of the inclined surface on the side, and the inclined surface on the upper side of the panel is more gradually inclined than the inclined surface on the lower side of the panel. 2. The projection according to claim 1, wherein the projection has a stripe shape extending in parallel to the left and right of the panel in use.
Reflector as described. 3. The reflector according to claim 1, wherein the projection has a substantially fan shape. 4. The reflector according to claim 1, wherein the projection has a perfect circular shape. 5. The reflector according to claim 1, wherein the protrusion has a horizontally long elliptical shape. 6. 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 provided inside or outside the panel of the rear substrate. A reflector having a plurality of fine projections, the projections being columnar in shape, and being gently inclined obliquely downward from the base surface to the panel in use. 7. 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 provided inside or outside the panel of the rear substrate. A reflector having a number of fine projections, the projections being in the shape of a horizontally long ellipse, and the peripheral surface being gently inclined with the central portion as the apex. 8. The method of manufacturing a reflection plate according to claim 5, wherein the surface of the metal film is brushed in a direction in which the panel is in the left-right direction in use, and then the surface is in a vertical direction in the use state. By brushing with reduced strength, the metal film surface has many fine horizontally long elliptical protrusions, and the vertices of these protrusions are ubiquitous under the panel in use and the side surfaces are inclined In use, the inclination angle of the inclined surface on the upper side of the panel in use is smaller than the inclination angle of the inclined surface on the lower side of the panel, and the inclined surface on the upper side of the panel is inclined more gradually than the inclined surface on the lower side of the panel. A method for manufacturing a reflector, comprising obtaining a reflector. 9. The method of manufacturing a reflection plate according to claim 6, wherein the metal is obliquely vapor-deposited from below toward the base so that a large number of fine columnar projections are formed from the base surface in use. A method of manufacturing a reflector, comprising: obtaining a reflector gently inclined obliquely downward to a panel. 10. The method of manufacturing a reflector according to claim 7, wherein the metal foil is biaxially stretched to have a large number of fine oblong projections on the surface, and the projections have a plurality of fine oblong projections. A reflective plate whose peripheral surface is gently inclined with the central portion as the apex. 11. A liquid crystal is interposed between a pair of front and rear substrates provided with electrodes, and the reflection plate according to any one of claims 1 to 7 is provided outside the panel of the rear substrate. A reflective liquid crystal display panel using a reflector. 12. A liquid crystal is interposed between a pair of front and rear substrates provided with electrodes, wherein the reflector according to any one of claims 1 to 7 is provided inside the panel of the rear substrate, and wherein the reflector is provided. Is a reflection type liquid crystal display panel using a reflection plate, which also functions as an electrode.