JPH11352330A - Hologram reflection film and reflection type liquid crystal display device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to realize a bright and high-contrast display. SOLUTION: A non-stretched film of polyvinyl, alcohol having no double refractiveness or polymer films, etc., of non-stretched materials of polyethylene terephthalate, polymethyl methacrylate, cellulose triacetate, polypropylene, polyethylene, polycarbonate, etc., are used as a supporting film of a hologram reflection film 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection type liquid crystal display device which does not require a special observation light source such as a backlight or an edge light. In particular, in a reflective liquid crystal display device using a liquid crystal panel capable of displaying information by controlling the polarization direction of display light, a structure that does not change the polarization direction of incident light enables brighter display than before. And a reflection type liquid crystal display device using the same.

[0002]

2. Description of the Related Art A reflection type liquid crystal display device having a metal reflection layer on the back surface of a liquid crystal panel (the side opposite to an observer) is known, and in recent years, it has been used instead of a metal reflection layer in an existing display device. It has been attempted to use a hologram as a reflection layer. The advantage of using a hologram as a reflective layer is that the reflection direction and the scattering angle can be controlled (display light can be emitted in a direction and range different from the regular reflection direction). Brighter and easier-to-view display can be performed than a display device using a reflective layer. Usually, a special hologram recording material (photosensitive material) is used for producing a hologram used for the hologram reflection film.

[0003] The existing hologram reflection film is obtained by coating a hologram recording material on a support layer by a known coating technique. With this support layer, a hologram made of fine interference fringes is photographed. Can be recorded. In general, holographic recording requires flatness and avoids vibration, so a glass with sufficient rigidity is used as a support layer, and the hologram recording material is peeled off from the glass at the stage of producing a product after recording. Is often transferred to another support layer. As a support layer of the hologram reflection film (product), a polymer film typified by polyethylene terephthalate is usually used.
Since it is manufactured by axial stretching, it has birefringence according to the stretching direction.

[0004] Here, the birefringence refers to the property that the refractive index of a material varies depending on the polarization direction of light.
When light linearly deflected in one direction is incident on the hologram reflection film, it causes a change in the polarization direction or a change in the deflection state to circular or elliptical deflection.

On the other hand, in the TN liquid crystal or STN liquid crystal used in the most common reflection type liquid crystal display device, the polarization direction of the linearly polarized light is changed by a liquid crystal panel, and the transparent and opaque films are arranged by polarizing films disposed above and below the panel. By making the part, it is possible to display information such as characters and figures.

Accordingly, when a support layer having birefringence is used as a hologram support layer in the hologram reflection film, the polarization state of incident light and reflected light changes in the hologram reflection film, and the polarization film is changed after reflection. There is a problem that the amount of transmitted light is reduced, and it is difficult to realize a bright display with high contrast.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a reflection type liquid crystal display device using a hologram reflection film as a reflection layer, and a hologram reflection film capable of realizing a bright and high contrast display and a reflection film using the same. It is an object of the present invention to provide a liquid crystal display device.

[0008]

In the present invention, an unstretched film of polyvinyl alcohol having no birefringence or polyethylene terephthalate, polymethyl methacrylate, cellulose triacetate, polypropylene, polyethylene, polycarbonate is used as a support film for the hologram reflection film. And a non-stretched polymer film of a non-stretched material. Alternatively, even when the support film has birefringence after hologram shooting and recording, the support film is separated from the hologram, and an adhesive layer is formed on at least one surface of the hologram layer, so that the hologram having no birefringence is obtained. A reflective film can be obtained.

<Operation> By forming the hologram support layer to have no birefringence (claim 1), the hologram reflection film as a whole can reflect without changing the polarization direction of incident light and reflected light at all. As a result, a brighter display with a higher contrast can be realized without reducing the characteristics of using the hologram. Alternatively, the hologram reflection film has no support layer, and has a configuration in which an adhesive layer is formed on at least one surface of the hologram (claim 2), so that the hologram reflection film is directly bonded to a liquid crystal panel or a polarizing film when incorporated in a liquid crystal display device. be able to.

Further, according to the third aspect of the invention, by using the hologram reflection film having no birefringence as a reflection layer, it is possible to realize a reflection type liquid crystal display device capable of performing bright display with high contrast.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view showing a reflection type liquid crystal display device using the hologram reflection film of the present invention.
The hologram reflection film 1 is arranged on the back surface of the liquid crystal panel 2, and polarizing films 3 and 4 are arranged before and after the liquid crystal panel 2, as shown in FIG. In FIG. 1, the liquid crystal panel 2, the polarizing films 3 and 4, and the hologram reflecting film 1 are shown separated from each other in order to schematically represent optical characteristics (optical paths of incident and reflected light). Are adhered and laminated by an adhesive layer (not shown).

When the illuminating light 5 enters the liquid crystal display device from the outside, first, only the light of one-way polarization component reaches the liquid crystal panel 2 by the first polarizing film 3, and the liquid crystal panel 2 changes the light according to the display pattern. After the optical rotation, the light reaches the second polarizing film 4.

The light transmitted through the second polarizing film 4 enters the hologram reflection film 1 and is reflected and diffracted at a desired reflection angle or scattering angle according to the characteristics of the hologram reflection film 1. The reflected light 6 passes through the polarizing film 4, the liquid crystal panel 2, and the polarizing film 3 again, and reaches the eyes 7 of the observer as pattern display light.

FIG. 2 schematically shows a layer structure of a reflection type liquid crystal display device using the hologram reflection film according to the first aspect of the present invention. The hologram reflection film of the present invention has a six-layer structure as shown in the figure, and includes a release layer 8, an adhesion layer 9, a hologram layer 10, a hologram support layer 11, an adhesion layer 12, and a metal reflection layer in this order from the light incident direction. It is 13. When incorporating the hologram reflection film of the present invention into a liquid crystal display device, the release layer 8 on the outermost surface is peeled off, and the hologram reflection film is attached to the polarizing film 4 with an adhesive layer 9 before use. For this reason, only one part is shown in the drawing because the peeling layer 8 has nothing to do with the incoming and outgoing light. In addition, in FIG. 1, in order to schematically represent the polarization direction of light, the respective layers are shown as being separated from each other. However, in reality, all the layers are adhered to form a single film. In addition, the polarizing film 3
Although the same polarization components 15 and 16 are transmitted by and 4, the invention is not limited to this.

In the hologram reflection film of the first aspect,
The hologram support layer 11 is a polymer film such as an unstretched film of polyvinyl alcohol having no birefringence or an unstretched film of polyethylene terephthalate, polymethyl methacrylate, cellulose triacetate, polypropylene, polyethylene, polycarbonate, or the like. As shown, the direction of the linearly polarized light 15 of the incident light is transmitted through the hologram support layer 11 without being changed, and is emitted as light 16 having the same polarization direction.

Examples of the polymer film having no birefringence include unstretched films of polyvinyl alcohol and unstretched films of polyethylene terephthalate, polymethyl methacrylate, cellulose triacetate, polypropylene, polyethylene, polycarbonate, and the like. Can be considered. Of course, the film is not limited to the above as long as the film has properties suitable for application of the hologram recording material and recording of the hologram and has no birefringence. Further, a film obtained by applying various substances to the surface of the film by coating or vapor deposition may be used.

FIG. 3 schematically shows a layer structure of a reflection type liquid crystal display device using the hologram reflection film according to claim 2 of the present invention. The hologram reflection film of the present invention,
As shown, it has a five-layer structure, and includes a release layer 8, an adhesive layer 9, a hologram layer 10, an adhesive layer 12, and a metal reflective layer 13 in this order from the light incident direction. When incorporating the hologram reflection film of the present invention into a liquid crystal display device, the release layer 8 on the outermost surface is peeled off, and the hologram reflection film is attached to the polarizing film 4 with an adhesive layer 9 before use. Therefore, in the drawing, the release layer 8
Are not related to the incoming and outgoing light, and only one portion is shown. Further, in FIG. 1, the layers are separated from each other in order to schematically represent the polarization direction of light. However, in reality, all the layers are adhered to form a single film. In addition, although the same polarization components 15 and 16 are transmitted by the polarizing films 3 and 4 in the figure, the present invention is not limited to this.

According to the hologram reflection film of the second aspect,
At the time of producing the hologram reflection film, the hologram support layer is peeled off from the hologram layer 10, and instead, the adhesive layer 1
By setting 2, the hologram support layer is eliminated from the layer configuration of the hologram reflection film, and the direction of the linearly polarized light 15 of the incident light is transmitted without changing as shown in the figure.

FIG. 4 schematically shows the layer structure of a conventional reflection type liquid crystal display device using a hologram reflection film. The conventional hologram reflective film generally has a six-layer structure as shown in the figure, and includes a release layer 8, an adhesive layer 9, a hologram layer 10, a hologram support layer 11, and an adhesive layer 12 in this order from the light incident direction. , The metal reflection layer 13. In FIG. 1, the layers are separated from each other in order to schematically represent the polarization direction of light. However, in reality, all the layers are bonded to form a single film.

In the conventional hologram reflection film, the hologram support layer 11 is a film having birefringence,
As shown, the direction of the linearly polarized light 15 of the incident light changes in the hologram support layer 11 and, for example,
7, and as a result, the reflected light component 18 having the same polarization direction as the incident light polarization direction 15 becomes the total reflection light 17.
Only a part of the inside. For this reason, the other polarized components are blocked by the back polarizing film 4, and the brightness and contrast of the displayed image are reduced.

[0021]

According to the present invention, there is provided a hologram reflection film capable of realizing a bright and high-contrast display in a reflection type liquid crystal display device using a hologram as a reflection layer instead of a metal reflection layer. In a conventional reflection type liquid crystal display device having a hologram reflection layer, the direction of polarization of incident light is changed due to the birefringence of a support layer constituting the hologram reflection layer. In the reflection type liquid crystal display device, incident light can be reflected without changing the polarization direction, and as a result, light utilization efficiency can be increased and a bright and high-contrast display can be realized.

[0022]

[Brief description of the drawings]

FIG. 1 is a schematic view showing one embodiment of a reflection type liquid crystal display device using a hologram reflection film of the present invention.

FIG. 2 is a schematic diagram showing a layer configuration of the hologram reflection film according to claim 1 of the present invention.

FIG. 3 is a schematic diagram showing a layer configuration of the hologram reflection film according to claim 2 of the present invention.

FIG. 4 is a schematic diagram showing a layer configuration of a conventional hologram reflection film.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Hologram reflective film 2 ... Liquid crystal panel 3, 4 ... Polarizing film 5 ... Illumination light 6 ... Reflected light 7 ... Observer 8 ... Release layer 9, 12 ... Adhesive layer 10 ... Hologram layer 11 ... Hologram support layer 13 ... Metal reflection Layer 14… Randomly polarized illumination light 15, 16, 18… Linearly polarized light 17… Elliptically polarized light

Claims (3)

[Claims] The present invention is used for a reflective layer of a reflective liquid crystal display device,
A hologram reflection film having a configuration in which a hologram made of a photosensitive material is formed on a support film, wherein the support film is an unstretched film of polyvinyl alcohol having no birefringence or polyethylene terephthalate, polymethyl methacrylate, cellulose triacetate, polypropylene. A hologram reflective film, which is a polymer film of a non-stretched material such as polyethylene, polycarbonate and the like. 2. The method according to claim 1, wherein the reflection type liquid crystal display device comprises:
A hologram reflection film having a configuration in which a hologram made of a photosensitive material is formed on a support film, wherein the hologram layer made of the photosensitive material does not have a support film, and at least one surface has an adhesive structure. Reflective film. 3. A hologram reflection film, wherein the hologram reflection film according to claim 1 or 2 is arranged on a back surface of a liquid crystal panel of a liquid crystal display device to form a reflection layer.