JPH11287991A - Reflective display - Google Patents

Abstract

(57) Abstract: Provided is a reflective display device capable of sufficiently brightening a display viewed from a predetermined direction and widening a viewing angle. A directional reflection plate (16) is provided facing a rear surface of a transmission type liquid crystal display element (10) to reflect incident light from the front of the liquid crystal display element (10) in a predetermined direction at a spread angle smaller than the incident angle range. The light diffusing means 22 and 2 are disposed between the front surface of the liquid crystal display device 10 and the rear surface of the liquid crystal display device 10 and the front surface of the directional reflector 16.
By providing No. 3, the range of taking in external light was widened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflective display device.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 8, a reflection type display device has a transmission type display device 1 such as a liquid crystal display device for controlling transmission of light, and a back surface of the display device 1. And the scattering reflection plate 2 disposed so as to be opposed to.

[0003] This reflection type display device uses external light such as natural light or room light incident from the front of a display body 1 to scatter and reflect light.
The display 1 is illuminated from the back with the reflected light, and the display is illuminated from the back. External light incident from the front is transmitted through the display 1 as shown by the arrow in the figure, and is a scattered reflection plate. The light is reflected by the light 2 and diffused into a wide area, enters the display 1 from its rear surface, and exits ahead of the display 1.

In general, a reflection type display device has a direction inclined to the upper edge side of the screen (left side in FIG. 8) with respect to the vertical line of the screen so that external light is mainly taken in from the upper edge side of the screen. The display is used in a direction in which bright external light is obtained, and the display is observed from a front direction, that is, near a direction perpendicular to the screen, or near a direction inclined slightly to the lower edge side of the screen from the vertical direction.

[0005]

However, the conventional reflective display device using the scattering reflector 2 has a problem that the display is dark. This is because the light reflected by the scattering reflector 2 is widely diffused in a direction in which the light does not enter the display 1, so that the reflected light that can be used as illumination light is only light in the diffusion range that enters the display 1. And display body 1
The divergence angle of the light that passes through and exits forward is large,
This is because the luminance of light emitted toward the viewing direction of display is low.

That is, the display of the display device is usually observed from the front as described above, but the conventional reflection type display device has a large spread angle of the light emitted to the front surface of the display 1. However, the light emitted toward the front direction of some of the emitted light is observed by the observer, and the light emitted toward the other oblique directions is hardly seen by the observer. It will be dark. The present invention
It is an object of the present invention to provide a reflective display device capable of sufficiently brightening a display viewed from a predetermined direction.

[0007]

According to the present invention, there is provided a reflection type display device, wherein a transmission type display body for controlling and displaying light transmission is provided so as to face a back surface of the display body, and a front side of the display body is provided. A directional reflector that reflects the incident light from the directional reflector at a spread angle smaller than the incident angle range, a front surface of the display body, and a space between the back surface of the display body and the front surface of the directional reflector plate. And a light diffusing means provided on at least one of them.

According to this reflective display device, the light entering from the front of the transmissive display body and transmitted through the display body is spread by the directional reflector at an angle of divergence smaller than the angle of incidence on the reflector. The reflected light is reflected in a predetermined direction, and the reflected light is transmitted through the display body and emitted forward, so that a display viewed from a predetermined direction can be made sufficiently bright.

Moreover, in this reflection type display device, the light diffusing means is provided on at least one of the front surface of the display body and the back surface of the display body and between the front surface of the directional reflector. And the viewing angle (observation angle range in which the display can be viewed with sufficient contrast) can be widened.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, the reflection type display device of the present invention faces the rear surface of the transmission type display body to reduce the incident light from the front of the display body to a divergence angle smaller than the incident angle range. A directional reflector that reflects in a predetermined direction is arranged, and a light diffusing unit is provided on at least one of the front surface of the display, and the rear surface of the display and between the front surface of the directional reflector. With this arrangement, the display viewed from a predetermined direction is made sufficiently bright and the viewing angle is widened.

In the reflection type display device according to the present invention, the directional reflection plate includes a reflecting member having a flat reflecting surface, and a plurality of rows of groove-shaped recesses along a predetermined direction formed on a back surface with a flat front surface. A first light guide member arranged with the back surface facing the reflection surface of the reflection member, and a first light guide member occupying each groove-shaped recess of the first light guide member. A second light-guiding member having a small refractive index, wherein the groove-shaped recess of the first light-guiding member has at least two inclined surfaces having different inclination angles with respect to a perpendicular of a reflection surface of the reflection member. It is preferable that the interface between the inclined surface and the second reflecting member forms an optical interface that reflects or transmits light incident on the interface in accordance with the angle of incidence.

[0012] Since the directional reflector has such a configuration, incident light transmitted through the display body and incident from the front surface of the first light guide member is refracted at the optical interface to be reflected on the reflection member. While entering, the reflected light reflected by the reflection surface of the reflection member is refracted at the optical interface and exits from the front surface of the first light guide member. The light can be reflected in a predetermined direction at a small spread angle.

In this directional reflector, the groove-shaped recess of the first light guide member may be a groove-shaped recess having a V-shaped cross section having two side surfaces inclined at different directions and inclined angles. The groove-shaped recess has a trapezoidal cross section having two side surfaces inclined at different directions and inclination angles and a bottom surface substantially parallel to the reflection surface of the reflection member, and the two side surfaces and the second light guide are provided. A boundary surface between the member and the optical interface that reflects or transmits incident light on the boundary surface according to the incident angle, and a boundary surface between the bottom surface and the second light guide member is a light transmission surface. By doing so, it is possible to emit incident light in a predetermined direction at a divergence angle smaller than the incident angle range of the incident light by using a material having a relatively small refractive index for the first light guide member.

In the reflection type display device according to the present invention, it is preferable that the light diffusing means is provided at least on a front surface of the display body, and the light diffusing means is provided on the front surface of the display body by the light diffusing means. External light incident from a direction greatly inclined with respect to the vertical direction can also be diffused and captured by the light diffusion means, so that the range of capturing external light is increased to increase the amount of captured external light, and the directional reflection is improved. Since the brightness of the light reflected by the plate can be further increased, the display can be made brighter.

Further, it is more preferable that the light diffusing means is provided on both the front surface of the display and between the rear surface of the display and the front surface of the directional reflector. in this way,
By providing light diffusing means on both the front surface of the display and between the rear surface of the display and the front surface of the directional reflector, these light diffusing means have a relatively haze value (scattered light transmittance). And the total light transmittance is small, a sufficiently wide viewing angle can be obtained. If the haze value of the light diffusing means is small, the sense of roughness of the display image due to the diffusion of light becomes less noticeable, so that it is possible to display a high quality image without the sense of roughness.

The light diffusing means may be a single diffusing plate. However, when the display is a liquid crystal display device having a polarizing plate on the outer surface, the light diffusing means is provided on the outer surface of the polarizing plate. As the diffusing means, it is desirable to integrally provide a roughened film or a scattered particle mixed film. In such a case, a single light diffusing plate can be provided between the front of the display or the back of the display and the directional reflector. The configuration of the display device can be simplified as compared with the case where the display device is arranged between the display device and the front surface.

[0017]

FIG. 1 is a side view of a reflection type display device according to a first embodiment of the present invention, and FIG. 2 is an enlarged view of a part thereof. The reflection type display device of this embodiment uses a liquid crystal display element as a transmission type display body for controlling and displaying light transmission. As shown in FIGS. 1 and 2, the transmission type liquid crystal display element 10, a directional reflector 16 disposed opposite to the rear surface of the liquid crystal display element 10, a first light diffusing means 22 provided on the front surface of the liquid crystal display element 10, The second light diffusion means 23 is provided between the rear surface and the front surface of the directional reflection plate 16.

Although the internal structure of the liquid crystal display element 10 is not shown, a pair of transparent substrates 11 and 12 are joined via a frame-shaped sealing material 13 and the sealing material 13 between the two substrates 11 and 12 is joined. Liquid crystal is sealed in a region surrounded by a circle. Transparent electrodes for applying an electric field to the liquid crystal layer are provided on the inner surfaces of both substrates 11 and 12, and the outer surfaces of both substrates 11 and 12 are provided on both surfaces. Polarizing plates 14 and 15 are provided, respectively.

The liquid crystal display element 10 may be any of an active matrix type, a simple matrix type, a segment type, and the like.
Any of a (twisted nematic) method, an STN (super twisted nematic) method, an ECB (birefringence effect) method, a dynamic scattering effect method, and a method using a ferroelectric liquid crystal may be used.

The directional reflector 16 is shown in FIGS.
As shown in FIG. 1, the reflecting member 1 having the flat reflecting surface 17a
7 and a groove-like recess 1 having a flat front surface and a rear surface along a predetermined direction.
9 are formed in a plurality of rows in parallel with each other, a first light guide member 18 having the back surface opposed to the reflection surface 17 a of the reflection member 17, and each groove of the first light guide member 18. The second light guide member 20 has a lower refractive index than the first light guide member 18 occupying the recess 19.

The reflecting member 17 is, for example, a flat-surface reflecting film formed by depositing or plating silver or aluminum on at least one surface of a resin film, and the reflecting surface 17a is a mirror surface.

The first light guide member 18 is made of a transparent resin material such as acrylic or triacetylcellulose (TAC) (preferably a transparent resin material having no optical anisotropy). A groove-like recess 1 having a length extending over the entire width thereof (the width in the front and back directions of the paper surface in the figure).
A plurality of rows 9 are formed in parallel with each other.

The groove-shaped recess 19 formed on the back surface of the first light guide member 18 has two side surfaces inclined in opposite directions and a bottom surface substantially parallel to the reflection surface 17a of the reflection member 17. The cross-section has a trapezoidal shape, and both side surfaces of these groove-shaped concave portions 19 have different inclinations with respect to a perpendicular line on the front surface of the first light guide member 18 toward the depth direction of the groove-shaped concave portions 19. It is inclined at an angle.

These groove-shaped recesses 19 are formed in parallel with each other at a predetermined interval, and the back surface of a flat portion between the groove-shaped recesses 19 of the first light guide member 18 is The light guide member 18 has a surface parallel to the front surface.

In FIG. 1, the first light guide member 1
8, each groove-shaped recess 19 is greatly exaggerated, but the width of each groove-shaped recess 19 (the width of the widest part opened to the back of the light guide member 18) is, for example, about 40 to 100 μm. The pitch of each groove-shaped recess 19 at this time is set to 50 to 150 μm, and each back portion between each groove-shaped recess 19 (the reflection surface 17a of the reflection member 17).
Is 1/4 of the width of the groove-shaped recess 19.
It is set to about １ ／.

The first light guide member 18 has a back surface between the respective groove-shaped recesses 19 and a reflection surface 17 of the reflection member 17.
The reflective member 17 is affixed to the reflecting member 17 by a transparent adhesive (not shown) (a double-sided adhesive tape may be used).

The second light guide member 2 provided so as to occupy the inside of each groove-shaped recess 19 of the first light guide member 18.
0 is, for example, an air layer. Therefore, the refractive index of the second light guide member 20 is smaller than the refractive index of the first light guide member 18.

The boundary surfaces between the two side surfaces of each groove-shaped concave portion 19 of the first light guide member 18 and the second light guide member 20 respectively have the incident light on the boundary surface set to the incident angle. Optical interfaces 21a and 21b that reflect or transmit light in accordance with the bottom surface of each groove-shaped recess 19 and the second light guide member 2
The boundary surface with 0 is a transmission surface 2 that transmits most of the incident light.
1c.

Optical interfaces 21 on both sides of the groove 19
Reference numerals a and 21b denote inclined surfaces having different inclination angles, and the front surface of the first light guide member 18 and the reflection surface 1 of the reflection member 17 are provided.
Inclination angle θ of one optical interface 21a with respect to the perpendicular to line 7a
1 and the inclination angle θ2 of the other optical interface 21b are θ1
> Θ2.

As shown in FIG. 1, the directional reflection plate 16 is provided on the optical interface 2 on both sides of each groove-shaped recess 19.
The optical interface 21a having a larger inclination angle (the inclination angle is θ1) with respect to the perpendicular of the reflection surface 17a of the reflection member 17 of the reflection member 17 is a screen (liquid crystal display element) which is the main external light capturing direction of the reflection display device. 10 front side) (FIG. 1
, The optical interface 21b having the smaller inclination angle (the inclination angle is θ2) faces the lower edge of the screen, and is disposed behind the liquid crystal 1. Note that the directions of the optical interfaces 21a and 21b are directions as viewed from inside the groove-shaped concave portion 19.

Next, a first light diffusing means 22 provided on the front surface of the liquid crystal display element 10,
The second light diffusing means 23 provided between the rear surface of the liquid crystal display element 16 and the front surface of the directional reflector 16 will be described. In this embodiment, the second light diffusing means 23 is provided on the outer surfaces of both substrates 11 and 12 of the liquid crystal display element 10. The light diffusing means 22 and 23 are integrally provided on the outer surfaces of the pair of polarizing plates 14 and 15, respectively, and these polarizing plates 14 and 15 have a light diffusing function.

FIG. 3 shows the liquid crystal display element 10.
FIG. 2 is an enlarged cross-sectional view of an example of the front-side polarizing plate 14, in which hatching is omitted, showing an example of the front-side polarizing plate 14. is there.

For the roughening film 24, for example, a transparent resin 24a is applied to the entire outer surface of the polarizing plate 14 similarly to the anti-glare treatment generally performed on the front surface of a liquid crystal display device or the like, and the entire film surface is coated. It is formed by roughening the minute uneven surface 24b, and the size and pitch of the unevenness on the surface are substantially uniform throughout.

FIG. 4 is an enlarged cross-sectional view showing another example of the front-side polarizing plate 14 without hatching. The polarizing plate 14 has a light diffusing means 22 on its entire outer surface.
The scattering particle mixed film 25 is provided integrally.

The scattering particle mixed film 25 mixes fine scattering particles 25b having a refractive index different from that of the transparent resin 25a substantially uniformly into a transparent resin 25a applied to the entire outer surface of the polarizing plate 14. It is formed.

The light diffusing means 22 formed on the front surface of the front-side polarizing plate 14 may be provided on the front surface of the polarizing plate 14 in addition to the above two examples. It may be formed by performing the same treatment as the anti-reflection treatment. Alternatively, the roughening film 24 shown in FIG. 3 and the surface anti-reflection treatment may be used together, or the scattering particle mixed film 25 shown in FIG. And the surface reflection prevention treatment may be used in combination.

On the other hand, the light diffusing means 23 provided on the outer surface (the surface facing the directional reflection plate 16) of the rear polarizing plate 15 of the liquid crystal display element 10 is preferably of a scattering particle mixing type. It is desirable that the diffusing unit 23 be in close contact with the front surface of the first light guide member 18 which is the emission surface of the directional reflection plate 16 without any gap.

FIG. 5 is an enlarged sectional view showing an example of the rear-side polarizing plate 15 without hatching. This polarizing plate 15 has a light-scattering means 23 as a light-diffusing means 23 on its entire outer surface. Are provided integrally.

The scattering particle mixed film 26 is made of a transparent resin 26
a is a scattering particle 2 having a different refractive index from the transparent resin 26a.
6b is formed into a film shape from a particle-mixed resin in which the particles 6b are dispersed almost uniformly, and a transparent adhesive 27 is applied to both surfaces of the scattering particle-mixed film 26, respectively.

The scattering particle mixed film 26 has one surface adhered to the outer surface of the polarizing plate 15 by the adhesive 27 and is integrated with the polarizing plate 15, and the other surface has The adhesive 27 causes the directional reflection plate 16
Is attached to the front surface of the first light guide member 18.

FIG. 6 is an enlarged cross-sectional view showing another example of the rear-side polarizing plate 15 without hatching. The polarizing plate 15 has a light diffusing means 23 on its entire outer surface.
In this case, an adhesive scattering particle mixed film 28 is provided integrally.

The adhesive scattering particle mixed film 28 is formed by dispersing a scattering adhesive 28b having a refractive index different from that of the adhesive resin 28a substantially uniformly in a transparent adhesive resin 28a by using the polarizing adhesive. The other surface of the scattered particle mixed film 28 is formed on the outer surface of the plate 15, and the first light guide member 1 of the directional reflector 16 is
8 is attached to the front surface.

This reflection type display device has a liquid crystal display element 10
The external light such as natural light or indoor light incident from the front of the liquid crystal panel is reflected by the directional reflector 16, and the reflected light illuminates the liquid crystal display element 10 from behind to display.

The incident path of external light and the exit path of the reflected light in the reflective display device will be described. The external light incident from the front of the liquid crystal display element 10 is, as indicated by the arrow in FIG. Light that is diffused by the first light diffusing means 22 on the front surface of the liquid crystal display device 10 and enters the liquid crystal display device 10 from the front surface thereof, and passes through the liquid crystal display device 10 is transmitted to the liquid crystal display device 10 by the directional reflection. The second diffusion means 23 between the front surface of the plate 16 (the front surface of the first light guide member 18)
And is incident on the first light guide member 18 of the directional reflector 16 from its front surface at various incident angles.

In this case, the reflective display device is used such that the direction inclined toward the upper edge of the screen with respect to the direction perpendicular to the screen is directed to the direction in which bright external light can be obtained. In other words, since the light is usually observed near the direction perpendicular to the screen or near the direction slightly inclined to the lower edge of the screen from the vertical direction, the external light mainly includes the upper edge of the screen,
That is, it is taken in from the upper edge side of the liquid crystal display element 10.

In the reflection type display device, as described above, the directional reflection plate 16 is connected to each of the groove-shaped concave portions 1.
9 among the optical interfaces 21a and 21b on both sides of the reflecting member 1
7, the optical interface 21a having a larger inclination angle with respect to the perpendicular of the reflection surface 17a (the inclination angle is θ1) is arranged toward the upper edge side of the screen which is the main external light capturing direction.
Light incident from the front of the liquid crystal display element 10 and transmitted through the liquid crystal display element 10 and incident on the first light guide member 18 of the directional reflection plate 16 from the front surface is the optical element having the larger inclination angle. Light is incident at various incident angles from directions along the inclination direction of the interface 21a.

The light incident on the first light guide member 18 from the front surface is transmitted through the inside of the light guide member 18 toward the rear surface, and of the light, the reflection surface 17 of the reflection member 17 is included.
The back portion in contact with a (portion between each groove-shaped recess 19)
Is reflected toward the front by the reflection member 17 on the back surface thereof, and is emitted from the front surface of the light guide member 18.

In the light transmitted through the inside of the first light guide member 18 toward the rear side thereof, each of the groove-shaped concave portions 1 is formed.
The light traveling toward 9 enters one of the optical interfaces 21a and 21b on both sides of these groove-shaped concave portions 19 and the transmission surface 21c on the bottom surface.

Of the light, the light incident on the optical interfaces 21a and 21b on both sides of the groove-shaped concave portion 19 at an incident angle larger than the critical angle for total reflection is applied to the optical interfaces 21b and 21a.
And travels inside the first light guide member 18.

The light includes a light traveling toward the back surface of the light guide member 18 (a portion between the groove-shaped concave portions 19) and a light traveling toward the optical interfaces 21 b and 21 a of the adjacent groove-shaped concave portions 19. The light traveling toward the back surface of the light guide member 18 is
The light is reflected by the reflecting member 17 and goes straight toward the front surface of the light guide member 18 and exits from the front surface, or enters the optical interfaces 21b and 21a of the adjacent groove-shaped concave portion 19 and enters the optical interfaces 21b and 21a. The light is totally reflected in the front direction by 21 a and exits from the surface of the light guide member 18.

In the light transmitted through the inside of the first light guide member 18 toward the rear side thereof, each of the groove-shaped concave portions 1 is formed.
Light incident on the optical interfaces 21a and 21b on both sides of the light 9 at an incident angle smaller than the total reflection critical angle (nearly perpendicular) passes through the optical interfaces 21a and 21b, is refracted in the back direction, and becomes second. The light enters the light guide member 20.

The reason why the light incident on the second light guide member 20 is refracted in the rear direction is that the optical interfaces 21a and 21b of the first light guide member 18 are respectively refracted by the first light guide member 18. Are inclined with respect to the perpendicular to the front surface of the first light guide member 1 on the optical interfaces 21a and 21b.
This is because light is incident from the front side of the light guide member 8 and the refractive index of the second light guide member 20 is smaller than the refractive index of the first light guide member 18.

Further, of the light transmitted through the inside of the first light guide member 18 toward the back side thereof, the groove-shaped recess 1
Most of the light incident on the transmission surface 21c on the bottom surface of the light transmission member 9 is transmitted through the transmission surface 21c, refracted in the rear direction, and is incident on the second light guide member 20.

The light transmitted through the optical interfaces 21a and 21b and the transmitting surface 21c, refracted in the rear direction, and incident on the second light guide member 20 is reflected by the light guide member 20.
The light travels through the inside toward the rear surface and is reflected by the reflection member 17.

The light reflected by the reflection member 17 passes through the second light guide member 20 and passes through the optical interfaces 21b and 2b.
1a and the transmission surface 21c, and the light incident on the transmission surface 21c is transmitted through the transmission surface 2c.
The first light-guiding member 18 is refracted in a direction approaching a perpendicular to the front surface of the first light-guiding member 18, passes through the inside of the first light-guiding member 18 toward the front surface, and exits from the front surface.

Further, the light is reflected by the reflection member 17,
The optical interface 21 passes through the inside of the second light guide member 20.
b, 21a are incident on the optical interfaces 21b, 21a.
The light is totally reflected toward the front surface or transmitted through the optical interfaces 21b and 21a to enter the first light guide member 18 according to the angle of incidence on the first light guide member 18.

Of the light, the optical interfaces 21b and 21b
The light totally reflected in the front direction by the light transmitting surface 21a or the optical interfaces 21a, 21
b and the transmission surface 21c or the optical interface 21
The first light guide member 18 is refracted in a direction approaching a perpendicular to the front surface of the first light guide member 18 after passing through the first light guide member 18, is transmitted through the first light guide member 18 toward the front surface, and is emitted from the front surface.

Further, the light is reflected by the reflecting member 17,
After passing through the second light guide member 20, the optical interfaces 21b, 2
1a, the optical interfaces 21b and 21a
Is refracted in a direction approaching a vertical line on the front surface of the first light guide member 18, passes through the inside of the first light guide member 18 toward the front surface, and exits from the front surface.

As described above, the directional reflection plate 16 is located on the upper edge side of the screen (the liquid crystal display element 1) which is the main direction of incidence of external light.
0 from the upper edge side) and transmitted through the liquid crystal display element 10 and incident on the first light guide member 18 from the front surface thereof.
The light is refracted in the rear direction by the optical interfaces 21a and 21b, which are boundaries between both side surfaces of the second light guide member 20, and is incident on the reflection member 17, and is reflected on the reflection surface 17a of the reflection member 17. The reflected light is transmitted to the optical interface 21.
The light is refracted in a direction approaching a vertical line on the front surface of the first light guide member 18 by the a and 21b, and is emitted from the front surface of the first light guide member 18, and varies from the incident direction of the main external light. It has a function of condensing light incident at an incident angle at an incident angle in a predetermined direction at a spread angle smaller than the incident angle range and emitting the light.

The light emitted from the front surface of the first light guide member 18 through the various paths, that is, the light reflected by the directional reflection plate 16 is
3, the light is incident on the liquid crystal display element 10 from the back thereof, and the light transmitted through the liquid crystal display element 10 is diffused by the first light diffusion means 22 and emitted forward.

According to this reflection type display device, the light incident from the front of the liquid crystal display element 10 and transmitted through the liquid crystal display element 10 is transmitted by the directional reflection plate 16 to the reflection plate 16.
The reflected light is reflected in a predetermined direction at a divergence angle smaller than the incident angle range, and the reflected light passes through the liquid crystal display element 10 and is emitted forward, so that the display viewed from the predetermined direction is sufficiently bright. Can be.

That is, the directional reflection plate 16 has a larger inclination angle with respect to a perpendicular line of the reflection surface 17a of the reflection member 17 among the optical interfaces 21a and 21b on both sides of each groove-shaped concave portion 19 (the inclination angle is θ1). ) Is arranged with the optical interface 21a facing the upper edge side of the screen, which is the main external light capturing direction, so that light incident at various incident angles from the main external light capturing direction spreads smaller than the incident angle range. Since the light is reflected in a predetermined direction at an angle, the spread range of the emitted light emitted in front of the reflective liquid crystal display device is, as shown in FIG. It is light with a smaller divergence angle.

The direction in which the light enters from the main external light capturing direction and is reflected by the directional reflection plate 16 depends on the first and second light guide members 1 of the directional reflection plate 16.
8, 20 and the optical interfaces 21a, 21 on both sides.
Since it is determined by the inclination angles θ1 and θ2 of b, by appropriately selecting these, it is possible to sufficiently brighten the display observed from the front direction, that is, the vicinity in the direction perpendicular to the front surface of the liquid crystal display element 10.

The directional reflector 16 shown in FIGS. 1 and 2
Is that the second light guide member 20 is an air layer having a refractive index of 1, and the first light guide member 18 has a refractive index of 1.49 ± 0.0.
5. Optical interfaces 21a and 21b on both sides of the groove-shaped recess 19
Of the one optical interface 21a inclined with respect to the vertical direction of the front surface of the first light guide member is 30 °.
± 5 °, the inclination angle θ2 of the other optical interface 21a is 20 °
The directional reflector 16 condenses reflected light of light incident at various incident angles from the inclination direction of the optical interface 21a having the larger inclination angle in the front direction and emits the reflected light. I do.

Further, in this embodiment, each groove-shaped concave portion 19 of the directional reflector 16 has two side surfaces inclined at different directions and inclination angles, and a bottom surface substantially parallel to the reflection surface of the reflection member. The optical interfaces 21a and 21b on both sides of the groove-shaped recess 19 are formed in a trapezoidal cross section having
Not only this, but also on the transmission surface 21c, which is the interface between the bottom surface of the groove-shaped recess 19 and the second light guide member 20,
Light passing through 1c is refracted as shown by the arrow in FIG.

As a result, the light refracting surface of the directional reflector 16 increases, and the first light guide member 18
By using a material having a relatively small refractive index, the incident light can be emitted in a predetermined direction at a spread angle smaller than the incident angle range of the incident light.

Further, the above-mentioned reflection type display device comprises a diffusing means 2 provided between the front surface of the liquid crystal display element 10 and the back surface of the liquid crystal display element 10 and between the front surface of the directional reflector 16.
Because of the provision of 2, 23, the range of taking in external light can be widened, the display can be made brighter, and the viewing angle can be widened.

That is, external light is incident at various angles of incidence from the front of the liquid crystal display element 10, but since the light diffusing means 22 is provided on the front surface of the liquid crystal display element 10, the liquid crystal display element 1
External light incident from a direction greatly inclined with respect to a direction perpendicular to the front surface of the light emitting element 0 can be diffused by the light diffusing means 22 and taken in along the path shown in FIG.

Therefore, it is possible to widen the range of taking in external light to increase the amount of taking in the external light and to further increase the luminance of the reflected light reflected by the directional reflector 16, so that the display is made brighter. Can be.

Further, external light entering from the front of the liquid crystal display element 10 is diffused by the light diffusing means 22 when entering the liquid crystal display element 10 from the front side, passes through the liquid crystal display element 10 and is behind the liquid crystal display element 10. When the light is incident on the directional reflector 16, the light is diffused by the light diffusing means 23 provided between the back surface of the liquid crystal display element 10 and the front surface of the directional reflector 16. In the process of being reflected by the light and being transmitted through the liquid crystal display element 10 and emitted forward, the light is diffused by the light diffusing means 23 and 22.
The viewing angle can be widened.

Further, the above-mentioned display device comprises the liquid crystal display element 1
0, and between the rear surface of the liquid crystal display element 10 and the front surface of the directional reflector 16, respectively.
23, these light diffusing means 2
Even if a relatively small haze value is used for 2, 23, a sufficiently wide viewing angle can be obtained.

The haze value is the haze value of the light diffusing means represented by scattered light transmittance / total light transmittance × 100. The haze value of one light diffusing means 22 and the haze value of the other light diffusing means 23 Is preferably in the range of 10 to 70, respectively.

If the haze value of the light diffusing means 22 and 23 is small, the roughness of the display image due to the diffusion of light becomes inconspicuous, so that it is possible to display a high quality image without the roughness.

The light diffusing means 22 and 23 may be a single diffusing plate, but in the above embodiment, FIGS.
As shown in (1), the light diffusing means 2 is provided on the outer surfaces of a pair of polarizing plates 14 and 15 provided on the outer surface of the liquid crystal display element 10.
2 and 23, a roughened film 24 or a scattered particle mixed film 2
Since 5, 26, and 27 are provided integrally, compared with a case where a single light diffusing plate is disposed between the front surface of the liquid crystal display device 10 or the back surface of the liquid crystal display device 10 and the front surface of the directional reflector 16. Thus, the configuration of the display device can be simplified.

In the first embodiment, the light diffusing means 2 is provided between the front surface of the liquid crystal display device 10 and the space between the rear surface of the liquid crystal display device 10 and the front surface of the directional reflector 16.
2 and 23, these light diffusing means 22 and 2 are provided.
3, one of them may be omitted.

As described above, when either one of the light diffusing means 22 and 23 is omitted, it is desirable to set the haze value of the light diffusing means to be used in the range of 20 to 80.
If the haze value of the light diffusing means is within this range, the light diffusing means 22 may be provided only on the front surface of the liquid crystal display element 10 or the back surface of the liquid crystal display element 10 and the directional reflector 16 may be provided.
In the case where the light diffusing means 23 is provided only between the front surface and the front surface, the viewing angle can be sufficiently widened.

However, when either one of the light diffusing means 22 and 23 is omitted, it is more preferable to leave the light diffusing means 22 on the front surface of the liquid crystal display element 10. By providing 22, not only can the viewing angle be sufficiently widened, but also, as described above, the range of taking in external light can be widened and the type display can be made brighter.

In the directional reflector 16 used in the first embodiment, the groove-shaped recess 19 provided on the back surface of the first light guide member 18 has two side surfaces inclined in opposite directions.
The groove 17 is formed in a trapezoidal cross section having a bottom surface substantially parallel to the reflection surface 17 a of the reflection member 17.
Numeral 9 is an inclined surface on at least both side surfaces thereof, and an interface between these side surfaces and the second light guide member 20 is an optical interface 21 for reflecting or transmitting incident light according to the incident angle.
Any cross-sectional shape may be used as long as it is a polygonal shape a and 21b.

FIG. 7 is an enlarged side view of a part of a directional reflector 16 showing a second embodiment of the present invention. In the directional reflector 16 of this embodiment, a groove-like recess 19 provided on the back surface of the first light guide member 18 is formed in a V-shaped cross section having two side surfaces inclined in opposite directions. Concave 19
A second light guide member 20 having a smaller refractive index than the first light guide member 18 is provided so as to occupy the inside of the concave portion 19, and a groove-shaped concave portion of the first light guide member 18 is provided therein. Boundary surfaces between both side surfaces of the second light guide member 19 and the second light guide member 20 are optical interfaces 21a and 21b for reflecting or transmitting light incident on the boundary surface according to the incident angle, respectively. Is the same as that of the first embodiment described above.

The directional reflection plate 16 converts the incident light having a predetermined incident angle range incident on the first light guide member 18 from the front surface thereof and the reflected light reflected by the reflection member 17 into the first light guide member 18.
Optical interface 21 on both sides of groove-shaped recess 19 of light guide member 18
The reflected light is emitted from the front surface of the first light guide member 18 at a spread angle smaller than the incident angle range of the incident light.

In the directional reflector 16 shown in FIG. 7, the second light guide member 20 is an air layer having a refractive index of 1, and the first light guide member 18 has a refractive index of 1,63 ± 0. 05, the inclination angle θ of one of the optical interfaces 21a, 21b on both sides of the groove-shaped concave portion 19, which is inclined in the main light incident direction.
1 is 30 ° ± 5 °, the inclination angle θ of the other optical interface 21a
2 is 20 ° ± 5 °, and the directional reflector 16
Reflects the reflected light of light incident at various incident angles from the direction along the inclination direction of the optical interface 21a having the larger inclination angle in the front direction and emits it.

In each of the directional reflectors 16 of the first and second embodiments, the second light guide member 20 provided in each groove-shaped recess 19 of the first light guide member 18 is made of air. Not limited to the layer, a transparent resin layer or the like having a lower refractive index than the first light guide member 18 may be used. In this case, the directional reflection plate 16 is provided on the reflection surface 17 a of the reflection member 17 by the transparent resin. A second light guide member 20 made of a resin layer or the like is formed in a plurality of rows, a transparent resin or the like having a high refractive index is applied thereon, and a portion covering the second light guide member 20 is a groove-shaped concave portion 19. It is also possible to manufacture by the method of forming the 1st light guide member 18 which became.

In the above embodiment, the directional reflection plate 16
To the optical interfaces 21 a, 21 on both sides of each groove-shaped recess 19.
b, the optical interface 21a having the larger inclination angle with respect to the perpendicular of the reflection surface 17a of the reflection member 17 is arranged toward the upper edge side of the screen which is the main external light capturing direction of the reflection type display device. The refractive index of the light guide member 18 and the second light guide member 20, the shape of the groove-shaped recess 19, and the optical interface 21
The inclination angles θ1 and θ2 of the a and 21b and the directions thereof may be set so that the intensity of light emitted from the display device increases in the viewing direction of display.

That is, for example, even if the viewing direction of the display is in the front direction, that is, in the vicinity of the direction perpendicular to the screen, or in the vicinity of the direction slightly inclined to the lower edge of the screen from the vertical direction,
The refractive indices of the first light guide member 18 and the second light guide member 20, the shape of the groove-shaped recess 19, and the optical interfaces 21a, 21
b depending on the inclination angles θ1 and θ2 of b.
To the optical interfaces 21 a, 21 on both sides of each groove-shaped recess 19.
The optical interface 21b having the smaller inclination angle with respect to the perpendicular of the reflection surface 17a of the reflection member 17 may be arranged toward the upper edge side of the screen which is the main external light capturing direction.

Further, the reflection type display device of the above embodiment is
Although the liquid crystal display element 10 is used for the display,
The display may be another electro-optical display element, a light-transmitting image printing film, or the like.

[0086]

According to the reflection type display device of the present invention, light incident from the front of the display body is reflected in a predetermined direction at a divergence angle smaller than the incident angle range, facing the rear surface of the transmission type display body. Along with disposing a directional reflector, the light diffusing means is provided on at least one of the front of the display, and the back of the display and the front of the directional reflector, The display viewed from a predetermined direction can be made sufficiently bright, and the viewing angle can be widened.

In the reflection type display device of the present invention, the directional reflection plate is formed by forming a reflection member having a flat reflection surface, and a plurality of rows of groove-shaped recesses extending in a predetermined direction on the back surface with a flat front surface. A first light guide member arranged with the back surface facing the reflection surface of the reflection member, and a first light guide member occupying each groove-shaped recess of the first light guide member. A second light-guiding member having a small refractive index, wherein the groove-shaped recess of the first light-guiding member has at least two inclined surfaces having different inclination angles with respect to a perpendicular of a reflection surface of the reflection member. Since the boundary between the inclined surface and the second light guide member forms an optical interface that reflects or transmits light incident on the boundary according to the angle of incidence, the display body is Incident light that has passed through and entered the front surface of the first light guide member is transmitted through the optical field. And is incident on the reflection member, and the reflected light reflected on the reflection surface of the reflection member is refracted at the optical interface and exits from the front surface of the first light guide member. Light can be reflected in a predetermined direction at a spread angle smaller than the incident angle range.

Further, in the reflection type display device of the present invention, the light diffusing means is provided at least on the front surface of the display body, so that the light incident from a direction greatly inclined with respect to the direction perpendicular to the front surface of the display body. Since light can also be diffused and captured by the light diffusion means, the range of capturing external light is increased to increase the capturing amount, and the luminance of light reflected by the directional reflector is further increased. , The display can be made brighter.

Further, by providing the light diffusing means on both the front surface of the display body and between the rear surface of the display body and the front surface of the directional reflector, the light diffusing means can be relatively provided. Even if a small haze value is used, a sufficiently wide viewing angle can be obtained, and if the haze value of the light diffusing means is small,
Since the roughness of the display image due to the diffusion of light becomes less noticeable, it is possible to display an image of good image quality without the roughness.

The light diffusing means may be a single diffusing plate. However, when the display is a liquid crystal display device having a polarizing plate on the outer surface, the light diffusing means is provided on the outer surface of the polarizing plate. As a means, if a roughening film or a scattering particle mixed film is provided integrally, a single light diffusion plate is disposed between the front of the display or the back of the display and the front of the directional reflector. The configuration of the display device can be simplified as compared with.

[Brief description of the drawings]

FIG. 1 is a side view of a reflective display device according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of a part of FIG.

FIG. 3 is an enlarged cross-sectional view illustrating an example of a front-side polarizing plate of a liquid crystal display element in the reflective display device, in which hatching is omitted.

FIG. 4 is an enlarged cross-sectional view of another example of a front-side polarizing plate of a liquid crystal display element in the reflection type display device, which is omitted from hatching.

FIG. 5 is an enlarged cross-sectional view of an example of a rear-side polarizing plate of a liquid crystal display element in the reflective display device, in which hatching is omitted.

FIG. 6 is an enlarged cross-sectional view of another example of the rear-side polarizing plate of the liquid crystal display element in the reflective display device, in which hatching is omitted.

FIG. 7 is a side view of a part of a directional reflector according to a second embodiment of the present invention.

FIG. 8 is a side view of a conventional reflective display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Liquid crystal display element 14, 15 ... Polarizer 16 ... Directional reflector 17 ... Reflective member 18 ... 1st light guide member 19 ... Groove-shaped recess 20 ... 2nd light guide member 21a, 21b ... Optical interface 21c ... Transmission surfaces 22, 23: Light diffusion means 24: Roughened film 25, 26, 27: Scattered particle mixed film

Claims (5)

[Claims] 1. A transmissive display body for controlling and displaying light transmission for disposing an incident light from the front of the display body, which is arranged opposite to a back surface of the display body and smaller than an incident angle range thereof. A directional reflector that reflects in a predetermined direction, a front surface of the display body, and a light diffusing unit provided on at least one of between a back surface of the display body and a front surface of the directional reflector. A reflective display device comprising: 2. The directional reflector according to claim 1, wherein the reflecting member has a flat reflecting surface and a plurality of rows of groove-shaped concave portions formed on a back surface of the reflecting member having a flat front surface and extending in a predetermined direction. A first light guide member disposed so as to face the reflection surface of the first light guide member, and a second light guide member having a smaller refractive index than the first light guide member occupying each groove-shaped recess of the first light guide member. A light guide member, wherein the groove-shaped concave portion of the first light guide member has at least two inclined surfaces having different inclination angles with respect to a perpendicular line of a reflection surface of the reflection member; 2. The reflective display according to claim 1, wherein a boundary surface between the light guide member and the second light guide member forms an optical interface that reflects or transmits light incident on the boundary surface in accordance with the incident angle. apparatus. 3. A light diffusing means is provided on both the front surface of the display and between the rear surface of the display and the front surface of the directional reflector. 3. The reflective display device according to 1. 4. The display device is a liquid crystal display device having a polarizing plate on an outer surface thereof, and the light diffusing means is a roughened film integrally provided on an outer surface of the polarizing plate. The reflective display device according to claim 1. 5. The display device is a liquid crystal display device having a polarizing plate on an outer surface thereof, and the light diffusing means is a scattered particle mixed film integrally provided on the outer surface of the polarizing plate. The display device according to claim 1.