JPS5962888A - Master hologram production method - Google Patents

Abstract

PURPOSE:To form physically intense strength and a high-contrast amplitude- type master hologram by vapor-depositing a metallic thin layer having a specific thickness on a light-transmissive substrate and coating a photoresist to the thin layer to attain a dry plate and exposing the metallic thin layer at the trough part of a holographic grating attained by photographing on this dry plate and removing a residual photoresist after etching the metallic thin layer partially. CONSTITUTION:A photoresist layer 3 is formed on the metallic thin layer 2 which is vapor-deposited onto the surface of a glass plate 1 and has a thickness of <= several 100Angstrom , and this glass plate 1 is baked to attain a dry plate 10, and when this dry plate 10 is irradiated with reference light L1 and object light L2 to perform development, a ruggedness corresponding to the photographed holographic grating is formed on the photoresist layer. In this case, the development is performed for a sufficiently long time to expose the metallic thin layer 2 in the part of the holographic grating. Next, the glass plate 1 is baked again to strengthen the holographic grating constituted with a remaining photoresist 3'. Thereafter, the exposed part of the metallic thin layer 2 is etched to leave only a required part 2', and the remaining photoresist 3' is removed, thus attaining a desired master hologram MH.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a master hologram, that is, an amplitude-type master hologram used for hologram replication.

It is well known that a master hologram and a hologram dry plate are closely stacked, exposed to 92 yen light, and then the hologram dry plate is developed to reproduce a hologram.

Conventionally, as a master hologram in such hologram duplication, a hologram prepared on a dry plate using a silver salt photosensitive aperture is generally used.

However, in such a master hologram, the silver particles are large, and due to the granularity of the silver, noise that affects the replicated hologram becomes a problem.

In addition, when a master hologram is reproduced, it is subjected to physical force by being brought into close contact with a hologram dry plate, so it is desirable that the master hologram has strong physical strength, but a master hologram using silver salt However, in terms of physical strength, there is also a problem in that cylindrical steel is not very strong.

Therefore, Kinoi υ1 aims to provide a method for producing an amplitude-type master hologram that solves the above-mentioned noise problem, has strong physical strength, and has good contrast.

The present invention will be explained below.

In FIG. 1 (1), the symbol l indicates a light-transmitting substrate. A master hologram is produced using the transparent yL substrate 1 of C as a base, and a glass plate, a transparent plastic plate, or the like can be used as this transparent substrate.

Here, for the sake of concreteness, the light-transmitting substrate 1 is assumed to be a glass plate, and in the following description, it will be referred to as a glass plate 1 instead of 4 light-transmitting substrates 1.

First, after thoroughly washing and drying this glass plate,
A thin metal layer 2 is formed on the surface by vapor deposition (Fig. 1 (Il
l). The above-mentioned cleaning may be performed by a cleaning method commonly used in vapor deposition technology.

The thickness of the metal thin layer 2 is set to be several hundred angstroms or less.

For example, aluminum is one of the preferable vapor-deposited gold .1A. Here, let us assume that aluminum is to be vapor-deposited.

When a thin layer of aluminum is formed by vapor deposition, the surface of the thin layer 2 becomes a mirror surface, which causes noise due to reflected light when photographing a holographic grating, which will be described later.

Therefore, in such a case, the surface of the aluminum thin layer 2 is oxidized with an aggressive chemical solution (2% sulfuric acid aqueous solution) to reduce the reflectance. When the deposited metal is, for example, chromium, the reflectance of the surface of the formed thin layer is low, so that such an oxidation treatment is not necessary. That is, such oxidation treatment may be performed in one step if necessary.

After thoroughly washing away the aggressive chemical solution with water,
After drying in an oven, a photoresist is uniformly applied on the thin metal layer 2 to form a photoresist layer 3 (FIG. 1 +m+).

To uniformly apply photoresist, for example, a glass plate 1 is vacuum-thickly coated on a rotary table of a coater, and a thin metal layer 2 is coated on a rotary table of a coater.
It is sufficient to drop bot type or negative type photo 7 stroke on top and spin coating at a rotation speed of 2000 to 5000 RPM.

After forming the photoresist layer 3, the dry plate JO is obtained by placing the photoresist layer 3 in an oven and baking it at a temperature of, for example, 90° C. for 30 minutes.

As shown in FIG. 1(1v), this dry plate 10 is irradiated with a reference source L1 and an object light L2, and a desired holographic grating is photographed.

So, l? When yffJ is applied, depending on the type of photoresist, 0 parts or unexposed parts of the photoresist are removed, and unevenness is formed in the photoresist layer, which corresponds to the holographic image taken. be done.

At this time, development is carried out for a sufficiently long time to expose the metal 7:9 layer 2 in the valley part of the holographic 1 plate as shown in Figure 1 (Vl). , 4' indicates the photoresist remaining on the thin metal layer 2 after development.

Place the nail in the oven again and bake for 30 minutes at a temperature of, for example, 90"C, and the remaining photoresist 3' (
Empty each holographic seedling.

The first woman used the etch liquid to remove the exposed gold (・jL
Etching the thin layer part leaves only the necessary part 2' (Note 11J (1'17), #you remove the remaining photo/print 3', the desired master porogram MJ4 is obtained ( Figure 1F1fID).

This master hologram NI [(ba, metal;, 9:
/, since the recording is formed in the force, the O1 buried strength is sufficiently strong.

Further, if light absorption by the glass plate 1 is ignored, the transmittance is 0% and 100%, and the hologram is a JI@ type hologram with much better contrast. Furthermore, noise such as noise caused by the graininess of silver salt does not occur in holograms.

In order to reproduce a hologram using the master hologram MI-I obtained in this way, as shown in FIG. Translucent substrate 2 such as
) is coated with a photosensitive material such as silver salt, dichromate gelatin, photorenost, etc. to form a photosensitive layer 22, and the master hologram ■ (is exposed from the transparent substrate side of the original). Thereafter, the hologram dry plate 20 may be subjected to processing such as development depending on the photosensitive material used.

When replicating as a relief type hologram, due to the high contrast of the master hologram ■-■, the peak portion of the duplicate hologram H is cut 1. The n1 shape is shown in Figure 2 (11
) As shown in ), the shape is good and almost rectangular.

Master hologram MU and hologram dry plate 20.

The secret method (Figure 2 (I)) can be the vacuum wisdom 2 method,
A method using Intex matching agent may also be used.

The source used for exposure is the space of the hologram) When the θ wave number is on the order of 100 millimeter lines, a mercury lamp source may be used, and when it is a high frequency of 1000 lines or more, a deep ultra vapor lamp source may be used. shall be.

The master hologram ■νII (has strong physical strength, so many holograms can be duplicated from one master hologram.

In addition, by increasing the thickness of the metal layer formed on the transparent yC substrate and performing the above master hologram manufacturing process', the only thing that can be obtained is a reflective diffraction seal,
Alternatively, it can be used as a master for making I) 4 double logograms by pressing one i+J function.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the process of the present invention,
FIG. 2 is a diagram illustrating the reproduction of a hologram. 1... Translucent substrate (glass plate), 2... Metal thin 1 layer, 3. Photo 1, Reno 1 layer, Ll... Object light, L2
...See ■1 shell, ■+-master hologram. shape

Claims (1)

[Claims] Transparent) "A thin metal layer having a thickness of several tens of amperes or less is formed by vapor deposition on a carbon substrate, and if necessary, in order to reduce the reflectance of the surface of the thin metal layer. , the above-mentioned gold (j8) thin layer was subjected to oxidation treatment. A photoresist was uniformly applied to the surface of the above-mentioned thin metal layer, and a dry plate was prepared by baking. Next, development was performed to expose the thin metal layer in the valleys of the porographic ink grid, and after baking again, the exposed 71% gold layer was etched with an etchant, and then, An amplitude-type master porogram manufacturing method characterized by removing residual photoleft.