JP2001265197A - Method for manufacturing transmission hologram - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a transmission type hologram suitable for mass production, without requiring antireflection treatment on the back face of each dry plate for photographing a hologram, by using an antireflection means for the back face which can be used in common for any dry plate for photographing a hologram, when a transmission type hologram is photographed or duplicated. SOLUTION: In the method for manufacturing a transmission type hologram, a transparent substrate 9 having a light-absorbing layer 10, laminated on the back face of the substrate, is stacked on the front face 14 of a dry plate for photographing a hologram via an index matching liquid 8 interposed and with the top face of the substrate 9 facing the back face 14 of the dry plate, so as to prevent reflection from the back face 14 of the dry plate 7, for photographing a hologram during the transmission type hologram is photographed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a transmission hologram, and more particularly to a method for producing a transmission hologram in which unnecessary interference fringes are prevented from occurring during hologram photographing.

[0002]

2. Description of the Related Art A transmission hologram is photographed by irradiating object light and reference light from the same side of a hologram photographing dry plate and causing them to interfere with each other in a hologram photosensitive material layer in the hologram photographing dry plate. A transmission type hologram recorded as described above, or a transmission type computer in which interference fringes are calculated by a computer, the interference fringes are drawn by an electron beam, and interference fringes are formed on a substrate by photolithography. A hologram (transmission-type CGH) is used as a transmission-type hologram master, and another hologram photographing dry plate is arranged in close contact with or slightly apart from the side of the transmission-type hologram master opposite to the reproduction illumination light incident side, and reproduces illumination from the master side. Duplicate illumination light corresponding to light is incident, and in the hologram photosensitive material layer of the hologram photographing dry plate, the diffracted light corresponding to the object light and the transmitted light corresponding to the reference light interfere with each other. The transmission hologram is duplicated.

When photographing or duplicating such a transmission hologram, object light and reference light transmitted through the hologram photosensitive material layer are reflected on the back surface of the transparent substrate supporting the hologram photosensitive material layer of the hologram photographing dry plate. Then, the reflected light again enters the hologram photosensitive material layer from the opposite side to form unnecessary interference fringes. Such unnecessary interference fringes cause unnecessary diffraction and deteriorate the reproduction characteristics of the hologram.

Therefore, conventionally, a layer that absorbs laser light transmitted through the hologram photosensitive material layer (backside antireflection layer: has an absorption characteristic that differs depending on the photographing wavelength) is usually provided on the back surface of the transmission type hologram photographing dry plate. ) To reduce the occurrence of unnecessary interference fringes due to reflection from the back surface of the transparent substrate.

As the method, for example, 1) a method in which a resin solution in which a dye is dissolved is generally applied to the back surface of the substrate and dried, and 2) a laser beam is absorbed through an adhesive whose refractive index is matched. Japanese Patent Application No. 11-602 proposes a back surface anti-reflection layer which uses an adhesive film having the following characteristics and simplifies the work step 1) by using the adhesive film.
09).

[0006]

However, in each of the above methods 1) and 2), it is necessary to perform a back-surface anti-reflection treatment for each hologram photographing dry plate, which is necessary for mass production of transmission holograms. Not very suitable.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object the purpose of back reflection which can be applied to each hologram photographing dry plate when photographing or duplicating a transmission hologram. It is an object of the present invention to provide a transmission hologram forming method suitable for mass production, which does not require a back reflection preventing process for each hologram photographing dry plate by using a prevention means.

[0008]

According to the present invention, there is provided a transmission type hologram forming method for achieving the above object, wherein a transmission type hologram is formed on a back surface of a hologram imaging dry plate in order to prevent reflection from the back surface of the hologram imaging dry plate. And a method of laminating a transparent substrate having a light absorbing layer on the back side on the front side through an index matching liquid.

In this case, the light absorption layer may be formed of an adhesive layer, and a resin film may be laminated on the side of the adhesive layer opposite to the transparent substrate.

The light absorbing layer may be a layer formed by applying and drying a resin solution in which a dye is dissolved.

The transmission hologram is photographed by a hologram photography method in which object light and reference light are incident from the same side of a hologram photography dry plate. A hologram duplication method in which light is incident on the same side of a photographing dry plate may be used.

In the present invention, the transparent substrate having the light absorbing layer laminated on the back surface is laminated on the back surface of the hologram photographing dry plate via the index matching liquid via the index matching liquid. Therefore, the light absorbing layer is laminated on the photographing system on the back surface. The fixed transparent substrate is always fixed, and a hologram photographing dry plate is placed on the hologram photographing liquid via the index matching solution, whereby each photographing can be performed. It is not necessary to remove the back reflection preventing layer from the hologram photographing dry plate after photographing, and the process can be greatly reduced. Further, since only the index matching liquid is basically used, the cost can be reduced, the transmission hologram can be easily photographed or copied, and the method is suitable for mass production.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a transmission hologram forming method according to the present invention will be described with reference to embodiments.

FIG. 1 shows an embodiment of the present invention in which a transmission hologram having the same characteristics as the original hologram is duplicated from the original hologram by the hologram duplication method.

FIG. 1 is a diagram showing an arrangement for performing such hologram duplication. For example, a prism 2 for efficiently entering duplicate illumination light 11 onto a transmission hologram master 1 made of transmission CGH. And a hologram photographing dry plate 7 is arranged on the opposite side via the index matching liquid 3.

The hologram photographing dry plate 7 is provided with a hologram photosensitive material layer 5 made of, for example, a photopolymer on a transparent substrate 6 and a protective layer 4 formed on the surface thereof.

On the back surface 14 side of the transparent substrate 6 of the hologram photographing dry plate 7, an index matching liquid 8 is interposed.
A transparent substrate 9 provided with a light absorbing layer 10 is laminated on the opposite surface.

Here, as the light absorbing layer 10 provided on the back surface of the transparent substrate 9, a light solution obtained by applying a resin solution in which the dye described in the section 1) of the prior art is dissolved to the back surface of the transparent substrate 9 and drying it is used. Absorbing layer or Japanese Patent Application No. 11 described in 1)
No. -60209 is an adhesive film having a property of absorbing laser light through an adhesive whose refractive index is matched.

Since the transmission type hologram is photographed or duplicated with such a layer arrangement (in FIG. 1, it is a duplicate, but the original 1 and the prism 2 are removed, and the object light and the reference light are incident from the same side). Is a normal transmission type hologram photographing.), The diffracted light 12 and the straight transmitted light 13 incident from the protective layer 4 side pass through the hologram photosensitive material layer 5 and the transparent substrate 6, and
It reaches the back surface 14 of the transparent substrate 6. When there is a difference in the refractive index on the back surface 14, reflected light 15 is generated on this surface. However, since the index matching liquid 8 is interposed, the reflected light 15 hardly reflects and reaches the laminated transparent substrate 9 and adheres to the back surface. It is substantially absorbed by the fixed light absorbing layer 10 and does not form unnecessary interference fringes.

As described above, the back surface reflection preventing means 20 composed of the transparent substrate 9 having the light absorbing layer 10 laminated on the back surface can be easily detached from the back surface 14 of the hologram photographing dry plate 7 via the index matching liquid 8. Because it is laminated
Unlike the related art, it is not necessary to perform a back reflection preventing process for each hologram photographing dry plate 7, and a transmission type hologram can be easily photographed or copied, which is a method suitable for mass production.

Here, it is desirable that the transparent substrate 9 of the back reflection preventing means 20, the transparent substrate 6 of the hologram photographing dry plate 7, and the index matching liquid 8 have substantially the same refractive index. If the refractive indices are perfectly matched, the anti-reflection effect on the back surface is equivalent to the case where the light absorption layer is provided on the back surface 14 of the hologram photographing dry plate 7. If the refractive index deviates by a certain degree or more, the performance of the photographed transmission hologram deteriorates.

The substrate 9 of the back reflection preventing means 20 is
A dye that absorbs laser light may be contained therein.
By making the substrate itself have absorption, the backside antireflection effect can be further improved. When such a dye-containing transparent substrate is used, if the dye concentration is high and the thickness is sufficient, laser light can be absorbed by the substrate body, so that the light absorbing layer 10 may not be provided.

A specific example will be described below. 486 nm light was used as the transmission hologram imaging wavelength. The refractive index n shown below is the refractive index at this wavelength.

A transparent substrate 6 of a hologram photographing dry plate 7;
The transparent substrate 9 of the back surface antireflection means 20 has a non-alkali glass 1737 (trade name) manufactured by Corning, n = 1.5
26 was used.

As the light absorbing layer 10, Japanese Patent Application No. 11-60 / 1990
The adhesive film for forming a hologram described in Example 1 of No. 209 was used. The hologram-forming pressure-sensitive adhesive film has the following configuration.

SK Dyne 160 which is an acrylic adhesive
4N (trade name: Soken Chemical Co., Ltd.) and Pine Crystal KE-100, a xylene-based tackifier resin [trade name: Arakawa Chemical Co., Ltd., refractive index 1.5946 (486n)
m)] at a mass ratio of 6: 4, and E-AX (trade name: Soken Chemical Co., Ltd.) as an epoxy-based curing agent.
By adding 0% by weight, a refractive index matching adhesive composition having a refractive index of 1.52 at a hologram imaging wavelength of 486 nm was obtained. The red dye Kayaset Re is used as a coloring agent.
d Add A-BR (manufactured by Nippon Kayaku) at 0.5 wt%,
A refractive index matching pressure-sensitive adhesive composition containing a colorant was obtained (refractive index 1.
52). PE using the pressure-sensitive adhesive composition as a support film
An adhesive layer was formed by uniformly coating a T film (thickness: 50 μm) with a thickness of 100 μm to obtain an adhesive film for hologram formation.

The hologram-forming pressure-sensitive adhesive film is referred to as a light absorbing layer 10, and the pressure-sensitive adhesive film has
A transparent substrate 9 having a refractive index of 1.526 (alkane-free glass 1737 (trade name) manufactured by Corning Incorporated) was attached to form a back reflection preventing means 20.

As the index matching liquid 8, Cargill oil n = 1.515 in a specific example, and xylene n = 1.506 in a specific example.

Using the above materials, the following experiment was conducted to confirm the back reflection preventing effect of the back reflection preventing means 20 of the present invention.

The total reflectance was measured when S-polarized laser light having a wavelength of 488 nm was incident at an incident angle of 50 ° to 80 °.

The layer structure is as follows: transparent substrate 6 (assuming hologram photographing dry plate 7) / index matching liquid 8: cargill oil / transparent substrate 9 of back reflection preventing means 20 / adhesive film for hologram formation of light absorbing layer 10 transparent substrate 6 (assuming a hologram photographing dry plate 7) / index matching liquid 8: xylene / transparent substrate 9 of back reflection preventing means 20 / hologram forming adhesive film of light absorbing layer 10 <Comparative Example> Transparent substrate 6 (hologram photographing dry plate) 7) / Adhesive film for hologram formation.

The measurement results of the specific examples are shown in the following table.

[0033] FIG. 2 shows the result as a graph.

From the above results, when the index matching liquid 8 used and the refractive indices of the transparent substrates 6 and 9 are approximately the same as described above, the hologram photographing dry plate is directly reduced while the working steps are shortened as described above. 7 was confirmed to have the same anti-reflection effect as the case where the hologram-forming pressure-sensitive adhesive film was attached.

As in the case of xylene used in the above, when the refractive index matching is deviated, the anti-reflection effect on the back surface is deteriorated. However,
Xylene has the advantages of being inexpensive and having good volatility, and the type of the index matching liquid 8 may be selected and used in consideration of the influence and degree of the reflection of the back surface of the hologram.

[0036]

As is apparent from the above description, according to the transmission hologram forming method of the present invention, a transparent substrate having a light absorbing layer laminated on the back surface thereof through an index matching solution is provided on the back surface of the hologram photographing dry plate. Since each layer is laminated on the front side, a transparent substrate with a light-absorbing layer laminated on the back side is always fixed to the photographing system, and each photographing is performed by placing a hologram photographing dry plate on it via the index matching liquid. This eliminates the need to provide a backside anti-reflection layer for each hologram photographing dry plate, and eliminates the need to remove the backside anti-reflection layer from the hologram photographing dry plate after photographing, greatly increasing the number of processes. Can be shortened to Also,
Basically, only the index matching liquid is used, so that the cost can be reduced, the transmission hologram can be easily photographed or copied, and this method is suitable for mass production.

[Brief description of the drawings]

FIG. 1 is a diagram showing an arrangement for implementing a transmission hologram forming method according to one embodiment of the present invention.

FIG. 2 is a diagram showing a measurement result for confirming a back reflection preventing effect according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Transmission type hologram master 2 ... Prism 3 ... Index matching liquid 4 ... Protective layer 5 ... Hologram photosensitive material layer 6 ... Transparent substrate 7 ... Dry plate for hologram photography 8 ... Index matching liquid 9 ... Transparent substrate 10 ... Light absorbing layer 11 ... Duplicated illumination light 12 Diffraction light 13 Straight transmitted light 14 Back surface of transparent substrate 15 Reflected light 20 Back surface antireflection means

Claims (5)

[Claims] In order to prevent reflection from the backside of a hologram photographing dry plate during transmission hologram photographing, a transparent substrate having a light absorption layer laminated on the backside thereof through an index matching liquid is provided on the backside of the hologram photographing dry plate. A method for producing a transmission type hologram, comprising laminating on the surface side. 2. The transmission hologram forming method according to claim 1, wherein said light absorbing layer comprises an adhesive layer, and a resin film is laminated on a side of said adhesive layer opposite to said transparent substrate. 3. The light absorbing layer according to claim 1, wherein the light absorbing layer is a layer formed by applying and drying a resin solution in which a dye is dissolved.
The method for producing a transmission hologram according to the above. 4. The transmission hologram is photographed by a hologram photographing method in which object light and reference light are incident from the same side of the hologram photographing dry plate. 3. The transmission hologram creating method according to claim 1. 5. The transmission hologram is photographed by a hologram duplication method in which diffracted light and transmitted light from a transmission hologram master are incident on the same side of the hologram photographing dry plate. 4. The method for producing a transmission hologram according to claim 3.