JP2003121827A - Hologram reflection plate and reflection type liquid crystal display device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hologram reflection plate capable of providing a reflection type liquid crystal display device wherein an observed image is bright and brilliant and the range in which the image can be observed is wide. SOLUTION: The hologram reflection plate 10 disposed in the rear of a liquid crystal panel and reflecting incident light in a specific direction and range is characterized in that a light diffusion agent is dispersed in an adhesion layer laminating a hologram 11 and a light reflection layer 12 and the hologram is to be a hologram of a volume phase transmission type, a surface relief type or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is arranged on the back side (opposite to an observer) of a display panel that defines a display pattern by transmitting / non-transmitting light, and does not require a back light to prevent incident external light. The present invention relates to a reflector and a reflective liquid crystal display device used in a liquid crystal display device of a type that obtains a display image by reflected light.

[0002]

2. Description of the Related Art In a liquid crystal display device, a reflection type liquid crystal display device is known in which a metal reflector is provided on the back side of a liquid crystal panel, and a back light is not required and external light from the observing side is used for reflection. However, by only providing the reflector on the back side, the illumination light (1a, 1b) is specularly reflected by the metal reflector (5) as shown in FIG.
a, 6b) are collectively reflected in the direction of specular reflection. Therefore, a bright image is displayed when observed in this specular reflection direction, but when observed out of this position, the image abruptly darkens, and flicker occurs due to reflection from the surface of the display device.

As one of the methods for solving this, in a reflection type liquid crystal display device, there is a registration publication No. 28549886.
As described in Japanese Patent Laid-Open No. 10-142424 and Japanese Patent Application Laid-Open No. 10-142424, a hologram reflection plate in which a volume phase transmission hologram and a light reflection layer are combined has been proposed and used.

By using a hologram, it is possible to display a brighter image in a designed specific direction, as compared with an existing light reflecting layer having a diffusive reflecting surface.
It becomes possible to emit the reflected light in a direction different from the regular reflection direction of the incident light. Further, it is not necessary to be aware of the image of the light source of the incident light due to the reflection on the hologram surface, and the reflection direction and the viewing area can be specified.

However, since the hologram has angle selectivity, incident light from a certain specific direction is transmitted and diffracted by the hologram, and a bright display can be observed in a certain specific reflecting direction and visual field. However, if the incident light deviates from a specific direction or the position of the eyes (8) of the observer does not fall within a specific reflection direction or viewing area, the display will be dark and under relatively limited environmental conditions. However, there is a problem that the effect can only be obtained.

[0006]

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a reflection type liquid crystal display device in which an image to be observed is bright and clear and has a wide observable range. It is to provide a hologram reflection plate capable of

[0007]

The invention according to claim 1 of the present invention made to solve the above-mentioned problems is a hologram reflection which is arranged on the back side of a liquid crystal panel and reflects incident light in a specific direction and range. In the plate, the hologram reflection plate is characterized in that a light diffusing agent is dispersed in an adhesive layer for laminating a hologram and a light reflection layer.

The invention according to claim 2 is the hologram reflection plate according to claim 1, wherein the hologram is a volume phase transmission hologram or a surface relief hologram.

Further, the invention according to claim 3 is the hologram reflector according to claim 1, wherein the hologram is composed of a plurality of different kinds of holograms.

The invention according to claim 4 is the hologram reflector according to claim 3, characterized in that the plurality of different kinds of holograms are multiple-recorded on the same photosensitive material.

The invention according to claim 5 is characterized in that a plurality of different kinds of holograms are recorded in the same photosensitive material by being divided into areas in a pattern and recorded. It is a hologram reflector.

The invention according to claim 6 is the hologram reflection plate according to claim 3, characterized in that the holograms of a plurality of different types are superposed.

Further, the invention according to claim 7 is the invention according to claim 1
A hologram reflection plate according to claim 6,
It is a hologram reflection plate characterized in that a polarizing layer of a liquid crystal panel is laminated and integrated.

Further, the invention according to claim 8 is based on claim 1
The hologram reflection plate according to claim 7,
It is a reflective liquid crystal display device characterized in that it is arranged on the back side of a liquid crystal panel on the side opposite to the observer.

In the hologram reflection plate, a light diffusing agent is dispersed on the light reflection layer of the surface relief hologram or in the adhesive layer for laminating the volume phase transmission type hologram and the light reflection layer so that the designed emitted light Since the light is diffused in the direction, it becomes possible to further increase the observable area.

Further, a plurality of different kinds of holograms are multi-recorded on the same photosensitive material, a region is divided into patterns, and a plurality of different kinds of holograms are superposed, so that the direction of the illumination light is restricted. It is possible to further increase the observation area where the bright reflected light can be seen, such as that the reflected light is sufficiently visible even if the observer moves the viewpoint.

The different holograms of different types emit "diffracted lights of different focal lengths for the same reproduction illumination light. Alternatively, they emit diffracted light of the same focal length for different reproduction illumination light. It is adjusted at the time of producing the hologram pattern by a photographing method or a computer method as described above.

By laminating a polarizing plate on the hologram reflection plate, the polarizing plate functions as a hologram protective layer and, when it is mounted on a reflection type liquid crystal display device, a polarizing plate required for a liquid crystal panel is provided. You can also combine.

Further, since the light diffusion layer has a function of an adhesive layer, the hologram reflection plate can be integrated at the same time when laminated.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the drawings.

First, FIG. 2 shows a reflection type liquid crystal display device using a hologram reflection plate. Hologram reflector (1
0) is arranged on the back side of the liquid crystal panel (3) and is composed of a hologram (11) having an angle selectivity and a light condensing function and a reflection layer (12). In FIG. 2, illumination light (incident light) (1a, 1b), pattern display light (7a, 7b)
In order to schematically explain the optical path of b), the hologram (1
Although 1) and the reflective layer 12 are shown separated from each other, they may be laminated and integrated.

Polarizing films (2) and (3) are provided on both sides of the liquid crystal panel (3), and when illumination light (incident light) (1a, 1b) enters the liquid crystal display device,
Only the polarized component in one direction reaches the liquid crystal panel (3) on the second polarizing film (2), and is rotated according to the display pattern on the liquid crystal panel (3), and then the second polarizing film (4). Reach

The light transmitted through the second polarizing film (4) is incident on the hologram reflection plate (10), but the liquid crystal panel (3) side of the hologram reflection plate (10) has angle selectivity,
A hologram (11) having a condensing function is provided, and the incident light is directly transmitted without being diffracted by the hologram due to its angle selectivity. The light transmitted through the hologram (11) is reflected by the reflection layer (12) on the back surface of the hologram and enters the hologram (11) again. This incident light (hereinafter, the incident light that is reflected and then re-entered is referred to as reflected light) is incident on the hologram at an incident angle that is opposite to the positive and negative of the first incident light, and is transmitted in accordance with the angle selectivity of the hologram. Be diffracted.

The transmitted diffracted light travels so as to be focused at the focal point position (F) of the hologram, passes through the polarizing film (4), the liquid crystal panel (3), and the polarizing film (2) again, and becomes visible to the observer's eyes. The pattern display light (7a, 7
Reach as b).

Since the angle selectivity of the hologram can be changed according to the conditions for producing the hologram (at the time of recording / recording), when the hologram reflection plate is used, it is not the position in the direction of the illumination light and the specular reflection direction but that shown in FIG. As shown, a bright display image can be observed at the position in front of the liquid crystal display panel.

However, when the above hologram reflector (10) is used, there is a drawback that the bright display image can be observed only in a small area.

In order to improve this drawback, a bright display image is obtained by providing an adhesive layer (13) in which a light diffusing agent is dispersed between the hologram (11) and the reflective layer (12) as shown in FIG. It is possible to enlarge the observable area.
That is, the difference from that shown in FIG. 2 is the same until the illumination light is incident on the hologram (11), but after passing through the hologram, the incident light is diffused by the light diffusion adhesive layer (13). Since it is reflected by the reflective layer (12) and diffused like the pattern display light (9a, 9b, 9c), the observable area becomes wider.

FIG. 4 shows a concrete example of the configuration of a hologram reflector which applies this. FIG. 4A shows a light diffusion adhesive layer (1) having a function of adhering a volume phase transmission hologram (11a) and a metal reflection layer (12) as holograms.
FIG. 3 is a cross-sectional view of the configuration of a hologram reflection plate (10) that is bonded and integrated in 3).

The volume phase transmission hologram (11a) is
It is prepared by a two-beam hologram imaging method using a volume phase hologram photosensitive material such as dichromated gelatin, a silver salt photosensitive agent, and a photopolymer.

The laser which is the light source is, for example, an argon ion laser (wavelength: 514.5 nm), and of the two light beams used for recording and recording the hologram, the divergent light that spreads from the point light source is the object light, and refer to the parallel light. A volume phase transmission hologram can be obtained by photographing and recording the incident angles of both lights as desired. Further, although the above description is for a hologram which is photographed and recorded by two-beam interference, a desired hologram lens drawn by an EB drawing device or the like is used as a master hologram to be a volume phase transmission hologram by a contact copy method or the like. It is also possible.

The light diffusing layer (13) is made of polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate copolymer resin, polyethyl acrylate resin, polymethyl methacrylate resin, etc., which are commonly used as adhesives. A coating material is prepared by dispersing glass spheres, titanium oxide, silica, calcium carbonate or other diffusing agent as a filler using an alcohol solvent such as acetone, ethyl acetate, ethanol or the like, and the coating agent is hologram or aluminum. It is applied to a metal foil reflection layer (12a) such as a foil and the hologram (1
1a) and the reflective layer (12a) are bonded together.

FIG. 4B shows another example of the hologram reflection plate, which is a sectional view of the structure of a polarizing film integrated with the hologram reflection plate. Aluminum is vapor-deposited on the back surface of the volume phase transmission hologram (11a) to form a reflection layer (1
2b), and this volume phase transmission hologram (11
A polarizing film (4) is adhered and laminated on the surface (a) with the above-mentioned light diffusion adhesive layer (13) having adhesiveness.

FIG. 4C is a sectional view of an example of a hologram reflection plate using a surface relief hologram.
Acrylic resin, polyethylene terephthalate resin, polystyrene resin, and polycarbonate resin are provided with a reflective layer (12c) by vapor-depositing aluminum on the surface on which a relief is formed by a mold having a hologram pattern, and the reflective layer (12c) surface is provided with the above-mentioned material. Adhesive light diffusion adhesive layer (1
The polarizing film (4) is adhered and laminated in 3).

FIG. 4D shows the hologram reflector (10).
FIG. 3 is a cross-sectional view of a structure in which the liquid crystal panel (3) and the liquid phase panel are integrated. Such integration can improve work efficiency when assembling the liquid crystal display device, and is a preferable configuration in the assembling process.

FIG. 5 shows a change in brightness (luminance) when the observation position of the liquid crystal display device is changed. When a specular reflection plate is used, it can be viewed brightly in the regular reflection direction as indicated by the brightness curve 31. On the other hand, when a hologram reflection plate is used, the light path is changed to 32. As you can see, you can see it brightly in the front direction. Further, by providing the light-diffusing adhesive layer of the present invention, as shown by reference numeral 33, it is possible to expand the brightly observable region.

Next, FIG. 6 (a) is a schematic diagram in which two different kinds of hologram patterns (21, 22) are recorded, and FIG. 6 (b) shows a hologram pattern (23 , 24, 25) is a diagram schematically showing the recorded data. By using the hologram reflection plate having a plurality of different hologram patterns, it is possible to complement the mutually observable region and to enlarge the brightly and clearly observable region.

[0037]

EFFECTS OF THE INVENTION In a reflection type liquid crystal display device using a hologram as a reflection layer instead of a metal reflection layer, by using a hologram, it becomes easy to control the reflection direction and the condensing range capable of bright display. In addition, by providing the light diffusion layer, it is possible to widen the area where bright viewing can be performed.

[Brief description of drawings]

FIG. 1 is a schematic view showing an optical path when a specular reflection plate is used.

FIG. 2 is a schematic diagram showing an optical path when a hologram reflector is used.

FIG. 3 is a schematic view showing an optical path when a light diffusion adhesive layer is provided on a holocrum reflector.

FIG. 4 shows a configuration of a hologram reflection plate, (a) is a reflection plate in which a volume phase transmission hologram and a metal reflection plate are integrated via a light diffusion adhesive layer, and (b) is a volume phase transmission hologram. (C) is a relief plate in which a polarizing film is formed as a reflection layer of a relief type hologram, and a polarizing film is integrated on the hologram surface via a light diffusion adhesive layer. A reflection plate having a polarizing film integrated on the surface via a light diffusion adhesive layer, (d)
[FIG. 3] is a cross-sectional view of a structure showing a liquid crystal panel unit and a reflection plate in which a hologram reflection layer is integrated.

FIG. 5 shows a brightness curve when a reflector is changed.

6A and 6B show examples in which a plurality of different hologram patterns are provided, FIG. 6A is a conceptual diagram for explaining a case where multiple recording is performed, and FIG.

[Explanation of symbols]

1a, 1b ... Illumination light 2 ... Polarizing film 3 ... Liquid crystal panel 4 ... Polarizing film 5 ... Reflector 6a, 6b ... Pattern display light 7a, 7b ... Pattern display light 8 ... The eyes of the observer 9a, 9b, 9c ... Pattern display light 10 ... Hologram reflector 11 ... Hologram 11a ... Volume phase transmission hologram 11b ... Relief type hologram 12 ... Reflector 12a ... Metal foil reflection layer 12b, 12c ... Vapor-deposited reflective layer 13 ... Light diffusion adhesive layer 21, 22 ... Hologram pattern 23, 24, 25 ... Hologram pattern 31, 32, 33 ... Luminance curve

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G09F 9/30 349 G09F 9/30 349D 349Z 9/35 9/35 F term (reference) 2H042 BA02 BA12 BA14 BA15 BA20 DA02 DA11 DA20 DE00 2H049 CA05 CA08 CA09 CA11 CA28 CA30 2H091 FA16Z FA19Z FA31Z FB13 FD06 FD15 GA17 LA16 5C094 AA10 AA12 BA43 DA13 DA14 EA06 EB04 ED11 ED20

Claims (8)

[Claims] 1. A hologram reflector, which is arranged on the back side of a liquid crystal panel and reflects incident light in a specific direction and range, wherein a light diffusing agent is dispersed in an adhesive layer for laminating a hologram and a light reflecting layer. A hologram reflector which is characterized by: 2. The hologram reflection plate according to claim 1, wherein the hologram is a volume phase transmission type hologram or a surface relief type hologram. 3. The hologram according to claim 1, wherein the hologram is composed of a plurality of different kinds of holograms.
The hologram reflection plate described in 1. 4. The hologram reflection plate according to claim 3, wherein the plurality of different kinds of holograms are multiple-recorded on the same photosensitive material. 5. The hologram reflection plate according to claim 3, wherein a plurality of different kinds of holograms are recorded on the same photosensitive material by being divided into areas in a pattern. 6. A structure in which a plurality of different kinds of holograms are overlapped with each other.
The hologram reflection plate described in 1. 7. A hologram reflection plate, characterized in that the hologram reflection plate according to any one of claims 1 to 6 and a polarizing layer of a liquid crystal panel are laminated and integrated. 8. A reflection type, characterized in that the hologram reflection plate according to any one of claims 1 to 7 is arranged on the back side of a liquid crystal panel on the side opposite to an observer. Liquid crystal display device.