JPH10300933A - Diffusion hologram optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a direction indication mark which can be provided by an easy method and can securely be identified in a diffusion hologram optical element used for a liquid crystal display device, etc. SOLUTION: A diffusion hologram 50 diffuses light which is made incident from above within a specific angle range and this diffusion hologram optical element in a rectangular sheet shape is provided with a cut mark 62 at the left upper corner as part of the rectangular shape or an opening mark cut into the sheet surface as the mark which indicates the direction of incidence characteristics or diffusion characteristics in the sheet surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diffusion hologram optical element, and more particularly to a diffusion hologram optical element used in a liquid crystal display device and the like, which has a specified directionality.

[0002]

2. Description of the Related Art The applicant of the present invention has proposed a liquid crystal display device using a diffuse transmission type hologram in Japanese Patent Application No. 7-313361. However, a specific direction in which light incident from a specific direction is defined as an observation area. There are a one-step photographing method and a two-step photographing method as a method of photographing a diffuse transmission hologram that scatters and diffracts only light.

As a one-step photographing method, the method shown in FIG. 6 is a diagram showing an arrangement for photographing when a visual field (viewing area) is set in the vertical direction of the hologram scattering plate.
A hologram is formed by irradiating a laser beam 3 from the backside of the hologram and using the scattered light as object light and the light transmitted through the scatter plate 2 without scattering as a reference beam 4 and causing interference in the hologram dry plate 1 to record. Used as the scattering plate 13. In this case, the scattering plate 2 needs to be larger than the hologram dry plate 1, and the area of the scattering plate 2 becomes a field of view (viewing area) of the hologram scattering plate 13 arranged at the position of the hologram dry plate 1.

A method shown in FIG. 7 is also a view showing an arrangement for photographing when a visual field (viewing area) is set in the vertical direction of a hologram scattering plate. The light scattered thereby is used as object light, and the light incident through a half mirror 5 disposed between the scattering plate 2 and the hologram dry plate 1 is used as the reference light 4 and recorded by causing interference in the hologram dry plate 1. Used as the hologram scattering plate 13. Also in this case, the scattering plate 2 needs to be larger than the hologram dry plate 1, and the area of the scattering plate 2 becomes the visual field (viewing area) of the hologram scattering plate 13 arranged at the position of the hologram dry plate 1. The method of FIG. 7 adjusts the light amount ratio between the object light and the reference light and compares the reference light
There is an advantage that it is easy to increase the degree of parallelism.

The method shown in FIG. 8 is a view showing an arrangement for photographing when the visual field is designed in a direction inclined with respect to the hologram scattering plate, and one image is placed at an off-axis position with respect to the hologram dry plate 1. Or a plurality of scattering plates 2 and 2 ′ are arranged, and laser beams 3 and 3 ′ are provided from the back of each of the scattering plates 2 and 2 ′.
And the light scattered thereby is incident as object light from obliquely forward of the hologram dry plate 1, the reference light 4 is incident from the front thereof, and the two are recorded in the hologram dry plate 1 by interfering with each other. Used as the hologram scattering plate 13. Also in this case, the scattering plates 2 and 2 'need to be larger than the hologram dry plate 1, and the regions of the scattering plates 2 and 2' are the same as the viewing region (viewing region) of the hologram scattering plate 13 arranged at the position of the hologram dry plate 1. Become. In the case of FIG. 8,
Although the scattering plates 2 and 2 'were arranged and exposed at the same time, the scattering plates 2 and 2' were exposed.
And 2 ′ may be sequentially arranged and recorded by multiple exposure.

Next, in the two-step photographing method, the intermediate hologram H1 is recorded, and the hologram scattering plate 13 as the target final hologram H2 is recorded using the intermediate hologram H1.
Is a method of recording. That is, in FIG. 9A, a scattering plate 2 is arranged opposite to a hologram dry plate 1 for the intermediate hologram H1, and a laser beam 3 is irradiated from the back thereof, and the light scattered thereby is used as object light as a hologram dry plate. 1, and the reference beam 4 is simultaneously incident from an oblique front thereof, and the two beams interfere with each other in the hologram dry plate 1 to record the intermediate hologram H1.

Next, as shown in FIG. 9B, the reproduced scattered light and the reference light interfere with each other in the hologram dry plate 1 'for the final hologram H2 by using the above-mentioned intermediate hologram H1. Record 13. In this case, the area of the intermediate hologram H1 with respect to the hologram dry plate 1 'becomes the field of view (viewing area) of the hologram scattering plate 13 arranged at the position of the hologram dry plate 1'. The recording is performed by irradiating the intermediate hologram H1 with light 4 ′ conjugated to the reference light 4 at the time of photographing the intermediate hologram H1 as reproduction illumination light, and causing scattered light reproduced from the intermediate hologram H1 to enter the hologram dry plate 1 ′ as object light.
At the same time, the reference light 4 ″ is made incident from the front of the hologram, and the two are interfered in the hologram dry plate 1 ′ to obtain the target hologram scattering plate 13. The reference light 4 ″ at the time of producing the final hologram H2 is as described above. As in the case of the one-step exposure method, three methods can be considered (FIGS. 6 to 8).

[0008] The present applicant has filed Japanese Patent Application No. 7-31236.
No. 2 proposed a liquid crystal display device using a diffuse reflection hologram. A diffuse reflection hologram that diffuses and reflects light incident from a specific direction only in a direction defined as an observation area is a Lippmann hologram using a scattering plate as a subject, and a paper titled "Holographic and Interferome".
tric Viewing Screens "(by Dietrich Meyerhofer, APPLI
ED OPTICS / Vol.12, No.9 / September 1973), and US Pat. No. 5,046,793. There are several methods for producing a diffuse reflection hologram composed of a Lippmann hologram (volume hologram).
11 shows a one-step imaging method, and FIG. 11 shows a two-step imaging method. In the one-step imaging method shown in FIG. 10, a reflection type hologram dry plate (Lipman hologram dry plate) 11 such as a photopolymer is arranged at a position previously defined as a diffuse reflection region with respect to a scattering plate 10 such as a ground glass, Coherent light 1 of a predetermined wavelength divided into two from the same light source from the back of
The scattered light 14 illuminated by the light source 2 and emitted to the front surface of the scattering plate 10 is incident on the reflection hologram dry plate 11 as object light, and another coherent light 13 of a predetermined wavelength divided into two from the same light source is used as reference light. Then, the diffuse reflection hologram is recorded on the reflection hologram dry plate 11 by making the reference light 13 proceeding in the opposite direction to the incident light assumed by the diffuse reflection hologram from the side opposite to the scattered light 14.

In the two-step photographing method shown in FIG. 11, a transmission type hologram dry plate 15 is arranged at a position which is predetermined as a diffuse reflection area with respect to a scattering plate 10 such as a ground glass as shown in FIG. At the same time, the light is illuminated from the back of the scattering plate 10 with the coherent light 12 having a predetermined wavelength divided by two from the same light source, and the scattered light 14 emitted from the front of the scattering plate 10 is incident on the transmission hologram dry plate 15 as object light, By making another coherent light 16 of a predetermined wavelength divided by the same light source into a reference light and incident at an arbitrary angle from the same surface side as the scattered light 14, the first light is incident on the transmission type hologram dry plate 15.
The transmission hologram, which is the hologram of the above, is recorded.

Next, the first hologram is designated as 17,
As shown in FIG. 11B, the hologram 17 is disposed at the position of the original transmission hologram dry plate 15 and the reflection hologram dry plate 20 is disposed at the position of the scattering plate 10.
The hologram 17 is reproduced at the same wavelength that travels to the opposite side of the reference light 16 at the time of recording so that the real image of the hologram 17 is formed at the position of the reflection type hologram dry plate 20 (the position of the scattering plate 10 in FIG. 9A). The hologram 17 is irradiated with illumination light 18.
Diffracted light 19 from the hologram is incident on the reflection hologram dry plate 20 as object light, and the reference light 21 traveling in the opposite direction to the incident light assumed in the diffuse reflection hologram is incident from the opposite side of the reflection hologram dry plate 20. Thus, a diffuse reflection hologram as a second hologram is recorded on the reflection hologram dry plate 20. With this method, a diffuse reflection hologram that limits the observation area to the range of the first hologram 17 can be manufactured. Further, using this hologram as an original, the hologram that is closely copied is also a diffuse reflection hologram in which the diffraction direction (scattering direction) of the original is maintained.

The diffuse transmission type hologram and the diffuse reflection type hologram photographed as described above are not usually used as they are, but are used as originals by copying holograms having similar characteristics by a hologram duplication method. Can be That is, in the case of a diffuse transmission type hologram photographed as shown in FIG. 6, for example, the diffuse transmission type hologram is used as an original 25, and as shown in FIG. The illumination light 27 is incident from the original 25 side in the same direction as the reference light 4 when the original 25 is photographed. Then, a transmission diffracted light 28 and a zero-order transmission light 29 that proceed in the same manner as the scattered light from the scattering plate 2 are generated from the master 25, and the two lights 28 and 29 interfere with each other in the hologram dry plate 26. A diffuse transmission hologram having the same characteristics as the original 25 is copied.

For example, in the case of a diffuse reflection type hologram photographed as shown in FIG. 10, the diffuse reflection type hologram is used as an original plate 30, and as shown in FIG. Are adhered to each other or overlapped at a slight interval, and the illumination light 32 is incident from the dry plate 31 side in the same direction as the reference light 13 at the time of photographing the original 30. Then, the original plate 30 generates reflected and diffracted light 33 that travels in the same manner as the scattered light from the scattering plate 10, and the illumination light 32 and the reflected and diffracted light 33 interfere with each other in the reflection type hologram dry plate 31, similar to the original 30 The diffuse reflection hologram having the characteristics described above is duplicated.

When the diffuse hologram or the diffuse hologram produced as described above is used for a liquid crystal display device, the hologram is bonded to a liquid crystal panel of the liquid crystal display device through steps shown in FIG. . FIG. 3 shows an example of a diffuse reflection type hologram, but in the case of a diffuse transmission type hologram, it is bonded to a liquid crystal panel through substantially the same steps.

As shown in the cross section of FIG. 3A, a diffusion hologram obtained through the photographing or duplicating process shown in FIGS. 6 to 13 (hereinafter, a diffuse transmission hologram and a diffusion reflection hologram mean both). In this case, the hologram layer is simply referred to as a diffusion hologram.) 40 is a hologram layer 41 on which the above-described diffusion hologram is recorded, and P is stacked on both sides thereof.
It is in the form of a roll film comprising protective layers 42 and 43 made of ET or the like. Here, as shown in the cross section in FIG. 3B, the polarizing plate 44 and the separator film 45 are adhered by the adhesive layer 46, and another adhesive layer 47 is provided on the exposed surface of the polarizing plate 44. Prepare the film 48 and see FIG.
(A) The one protective layer 43 of the diffusion hologram 40 is peeled off, and a polarizing film 48 is adhered thereon via an adhesive layer 47, thereby producing a sheet-shaped diffusion hologram 49.

Such a sheet-shaped diffusion hologram 49
Is punched in accordance with the size of the liquid crystal panel to be bonded, thereby producing a piece-shaped diffusion hologram 50 as shown in FIG. Next, a piece-shaped diffusion hologram 5
No. 0 separator film 45 is peeled off, and an adhesive piece type diffusion hologram 5 as shown in the cross section in FIG.
Get 0 '. This adhesive piece form diffusion hologram 5
0 'is attached to the back surface of the liquid crystal panel 51 via the adhesive layer 46 as shown in FIG.
The liquid crystal display device 52 as shown in FIG.

Here, the configuration of one example of the liquid crystal display device 52 will be briefly described. The liquid crystal panel 51 of the liquid crystal display device 52 is, for example, a twisted nematic sandwiched between two glass substrates 53 and 54. And the like, a liquid crystal layer 57,
A uniform transparent counter electrode 5 is provided on the inner surface of one glass substrate 54.
6, a transparent display electrode 55 and a black matrix (not shown) are provided as necessary on the inner surface of the other glass substrate 53 independently for each pixel. In the case of a color display device, a transparent display electrode 55, a color filter, and a black matrix are provided independently for each of the liquid crystal cells R, G, and B on the inner surface of the other glass substrate 53.
An alignment layer (not shown) is also provided on the liquid crystal layer 57 side of the electrodes 55 and 56, and a polarizing plate 58 is attached to the outer surface of the observation side glass substrate 53 in advance, or an adhesive piece is formed. It is attached after attaching the diffusion hologram 50 '. Then, as described above, the polarizing plate 58
A polarizing plate 44 and a diffuse reflection type hologram 41 are attached to the opposite side, and the polarizing plates 44 and 58 are arranged, for example, so that their transmission axes are orthogonal to each other. By controlling the voltage applied between the transparent display electrode 55 and the transparent counter electrode 56 for each pixel of the liquid crystal display device 52 to change the transmission state, display is possible.

[0017]

The diffusion hologram 49 as described above is, for example, a diffuse reflection type hologram.
As shown in FIG. 4, the direction of the incident light from the light source 60 for exhibiting a predetermined diffusion characteristic for the observer is determined, and therefore, the relative direction of the diffusion hologram 49 when affixed to the liquid crystal panel is also determined. ing. Conventionally, in order to indicate this direction, as shown in FIG.
Separator film 45 releasably bonded to 9
The direction indicating mark 61 is formed on the upper side by printing.

However, in such a method, the number of steps for printing the direction indicating mark 61 increases, and the cost is increased. Further, when the diffusion hologram 49 is a small piece, it is necessary to finely insert the direction indication mark 61, so that an inexpensive printing method cannot be used. Further, when the diffusion holograms 49 are stacked and stored after such printing, the prints are transferred to the protective layer 42 of the adjacent diffusion hologram 49, and cannot be used.
In addition, as shown in FIG. 3E, when the step of bonding the piece-shaped diffusion hologram 50 to the liquid crystal panel 51 via the adhesive 46 on the back surface is to be automatically performed by a machine, the direction indicating mark 61 is used. There is also a problem that it is not easy to mechanically detect the.

The present invention has been made in view of such problems of the prior art, and an object thereof is to provide a diffusion hologram optical element used for a liquid crystal display device or the like by a simple method, and To provide a direction identification mark that can be reliably identified.

[0020]

A diffusion hologram optical element according to the present invention, which achieves the above object, is a diffusion hologram for diffusing light incident from a predetermined direction within a specific angle range. In the diffusion hologram optical element having the above, the mark indicating the direction of the incident characteristic or the diffusion characteristic in the sheet surface is provided as a partially cutout mark of the outer shape or an opening mark cut in the sheet surface. A diffusion hologram optical element, characterized in that:

In this case, the sheet form having a constant outer shape is typically a rectangular sheet form. The diffusion hologram optical element includes a diffuse reflection hologram and a diffusion transmission hologram. Further, the diffusion hologram optical element can be made of a volume hologram.

Further, the diffusion hologram optical element of the present invention can be used as a diffusion plate of a liquid crystal display.

In the diffusion hologram optical element of the present invention, the mark indicating the direction in the sheet surface of the incident characteristic or the diffusion characteristic is a notch mark of a part of the outer shape or an opening mark cut in the sheet surface. Since it is provided, it is possible to reliably identify the vertical direction when assembling into a liquid crystal display device or the like. In addition, by using a plurality of marks having different shapes, it is possible to easily distinguish two or more marks even when they are flown simultaneously in an assembling process or the like. further,
Since such a mark can be produced simultaneously with the punching process, it can be produced without any extra steps and cost.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the diffusion hologram optical element of the present invention will be described. FIG. 1 (a) to (d)
FIGS. 4A and 4B are plan views of four examples of the diffusion hologram 50 manufactured based on the present invention. FIGS. These diffusion holograms 50
Is manufactured during the punching process from FIG. 3B to FIG. 3C. In the case of FIG. 1A, a notch 62 is provided at the upper left corner of the diffusion hologram 50 having a rectangular outer shape, and indicates that the illumination direction of the diffusion hologram 50 is upward. 1B and 1D, notches 63 and 63 'are provided near the upper corner of the left side of the diffusion hologram 50 having a rectangular outer shape, and the illumination direction of the diffusion hologram 50 is indicated to be upward. doing.
Similarly, in the case of FIG. 1 (c), a minute hole 64 is provided near the upper left corner of the diffusion hologram 50 having a rectangular outer shape, and indicates that the illumination direction of the diffusion hologram 50 is upward. . Such notches 62, notches 6
The vertical direction of the diffusion hologram 50 can be reliably identified when incorporated in a liquid crystal display device by the holes 3, 64, and 63 '. In FIGS. 1B and 1D, even the same notch has a different shape, so that two or more types can be easily distinguished even when they are simultaneously flown in an assembling process or the like.

In order to produce a diffusion hologram 50 having such a notch, notch, hole or the like near the corner, a sheet-shaped diffusion hologram 49 shown in FIG.
When the piece-shaped diffusion hologram 50 shown in FIG. 3 (c) is manufactured by punching, a die is simply manufactured so as to be able to be punched along, for example, a broken line shown in FIG. The diffusion hologram 50 shown in FIG.

The notches, notches, holes, and the like provided near the corners of the diffusion hologram 50 are shown in FIG.
After assembling and mounting in a liquid crystal display device as shown in (f),
There is no problem because it is provided at a position concealed by the decorative panel or the like.

Although the diffusion hologram optical element of the present invention has been described based on the embodiments, the present invention is not limited to these embodiments, and various modifications are possible. For example, the number of notches, notches, holes, and the like provided in the diffusion hologram 50 is not limited to one and may be two or more, and the shape is not limited to the embodiment of FIG. Further, the diffusion hologram optical element of the present invention is not limited to the reflection type or transmission type diffusion plate of the liquid crystal display device as shown in FIG.

[0028]

As is clear from the above description, according to the diffusion hologram optical element of the present invention, the mark indicating the direction of the incident characteristic or the diffusion characteristic in the sheet surface is a notch mark of a part of the outer shape, Alternatively, since it is provided as an opening mark cut in the sheet surface, the vertical direction thereof can be reliably identified when incorporated into a liquid crystal display device or the like. In addition, by using a plurality of marks having different shapes, it is possible to easily distinguish two or more marks even when they are flown simultaneously in an assembling process or the like. Further, since such marks can be produced simultaneously with the punching process, they can be produced without any extra steps and costs.

[Brief description of the drawings]

FIG. 1 is a plan view showing some examples of a diffusion hologram manufactured according to the present invention.

FIG. 2 is a diagram showing an example of a punching line when a diffusion hologram of the present invention is manufactured by punching.

FIG. 3 is a diagram showing a process of assembling a liquid crystal display device by attaching a diffusion hologram to a liquid crystal panel.

FIG. 4 is a diagram for explaining that the direction of incident light is determined in a diffusion hologram.

FIG. 5 is a diagram showing a direction indication mark by printing on a conventional diffusion hologram.

FIG. 6 is a diagram for explaining one method for producing a diffuse transmission hologram by a one-step imaging method.

FIG. 7 is a diagram for explaining another method for producing a diffuse transmission hologram by a one-step photographing method.

FIG. 8 is a diagram for explaining still another method of producing a diffuse transmission hologram by a one-step imaging method.

FIG. 9 is a diagram for explaining a method of manufacturing a diffuse transmission hologram by a two-step imaging method.

FIG. 10 is a diagram for explaining a method of manufacturing a diffuse reflection hologram by a one-step imaging method.

FIG. 11 is a diagram for explaining a method for producing a diffuse reflection hologram by a two-step photographing method.

FIG. 12 is a diagram for explaining a method of replicating a diffuse transmission hologram from a diffuse transmission hologram master.

FIG. 13 is a diagram for explaining a method of replicating a diffuse reflection hologram from an original diffuse reflection hologram.

[Explanation of symbols]

 Reference Signs List 40 diffusion roll hologram 41 hologram layer 42, 43 protective layer 44 polarizing plate 45 separator film 46, 47 adhesive layer 48 polarizing film 49 sheet diffusion hologram 50 piece diffusion hologram 50 ' Adhesive piece type diffusion hologram 51 ... Liquid crystal panel 52 ... Liquid crystal display device 53, 54 ... Glass substrate 55 ... Transparent display electrode 56 ... Transparent counter electrode 57 ... Liquid crystal layer 58 ... Polarizing plate 60 ... Light source 62 ... Notch 63, 63 ' … Notch 64… Small hole

Claims (6)

[Claims] 1. A diffusion hologram optical element having a sheet shape having a constant outer shape, comprising: a diffusion hologram for diffusing light incident from a predetermined direction within a specific angle range;
A diffusion hologram optical element, wherein a mark indicating the direction of the incident characteristic or the diffusion characteristic in the sheet surface is provided as a partially cutout mark of the outer shape or an opening mark cut in the sheet surface. element. 2. The diffusion hologram optical element according to claim 1, wherein the sheet form having the predetermined outer shape is a rectangular sheet form. 3. The diffusion hologram optical element according to claim 1, wherein the diffusion hologram optical element is a diffuse reflection hologram. 4. The diffusion hologram optical element according to claim 1, wherein the diffusion hologram optical element is a diffusion transmission hologram. 5. The diffusion hologram optical element according to claim 1, wherein the diffusion hologram optical element comprises a volume hologram. 6. The diffusion hologram optical element according to claim 1, wherein the diffusion hologram optical element is used as a diffusion plate of a liquid crystal display device.