JP2000180629A - Manufacture of holographic diffraction grating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a holographic diffraction grating capable of producing white diffractive light from a fed white light and being fabricated through one run of optical recording process. SOLUTION: A directional diffusion plate 1 having diffusional property is installed in tight attachment or proximity to a holographic recording material 2, and a reference light 3 is put incident in the transmitting direction of the diffusion plate 1 while a physical light 4 is given incident in the diffusing direction, and interferential striations formed after passage of the diffusion plate 1 are recorded in the holographic recording material 2, and thereby an intended holographic diffraction grating to diffract a white light is accomplished.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a holographic diffraction grating for the purpose of deflecting a white light beam and manufacturing a white light reproduction image hologram.

[0002]

2. Description of the Related Art If a diffraction grating can be used to deflect white light, it can be used as an excellent member for light distribution of illumination. However, in the conventional diffraction grating, a spectrum is generated when white light is incident because the diffraction angle depends on the wavelength, and cannot be used for such an application. In order to obtain white diffracted light, a method of compensating chromatic dispersion by combining two diffraction gratings or producing an image hologram of a diffused object has been considered, but any of these methods is complicated, expensive and large. Was difficult.

[0003]

The present invention relates to a method of manufacturing a holographic diffraction grating capable of obtaining a white light diffracted light in one step with simple equipment, regardless of the conventional manufacturing method using complicated processes and equipment. It is.

[0004]

(A) A directional diffusion plate 1 having a diffusivity in a specific direction is placed in close contact with or close to a holographic recording material 2. (B) The reference light 3 is incident from the direction of transmission of the directional diffuser 1, the object light 4 is incident from the direction of diffusion, and the reference light 3 transmitted through the directional diffuser 1 is diffused by the directional diffuser 1. The holographic diffraction grating 6 is manufactured by recording the interference fringes formed by the interference of the object light 5 on the holographic recording material 2. (C) The holographic diffraction grating 6 manufactured according to the present invention has a diffraction grating structure similar to an image hologram in which a real image of a plane diffuse object is recorded on a hologram surface, and is viewed from the same direction as the reference light incident direction during recording. When white light is incident, white diffracted light 8 is obtained in the direction of the object light 5 during recording. The white diffracted light 8 is diffused moderately and shows very excellent characteristics when used for illumination light distribution and the like. When white light is incident from a direction conjugate to the reference light incident direction during recording, a diffracted light conjugate to the white diffracted light 8 is obtained, and light distribution characteristics slightly different from the above are obtained. (D) An original film 9, a projection lens 10 and the like are provided on the optical path of the object light 4 when the holographic diffraction grating of the present invention is manufactured, as shown in the example of FIG. By imaging, an image hologram including image information can be easily manufactured.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the present invention will be described with reference to an example. A directional diffusion plate 1 having a diffusivity in a specific direction is placed in close contact with or close to a holographic recording material 2. In the case where the directional diffusion plate 1 and the holographic recording material 2 are placed in close contact with each other, by performing liquid-immersion between the directional diffusion plate 1 and the holographic recording material 2 and performing refractive index matching, the occurrence of Newton rings can be prevented. In the above configuration, the reference light 3 is incident from the transmission direction of the directional diffusion plate 1 and the object light 4 is incident from the diffusion direction by the coherent laser light. The reference light transmitted through the directional diffusion plate 1 and the object light 5 diffused by the directional diffusion plate 1 form interference fringes by interference. The holographic diffraction grating 6 is manufactured by recording the interference fringes on the holographic recording material 2.
The manufactured holographic diffraction grating 6 has a diffraction grating structure similar to an image hologram in which a real image of a plane diffuse object is recorded on a hologram surface.
A white image is obtained on the diffraction grating surface by mixing diffracted lights having different wavelengths that are close to each other. This white image is
It is the same as the diffused white diffracted light, and when white light enters from the same direction as the reference light incident direction during recording, white diffracted light 8 is obtained in the direction of the object light 5 during recording. When white light is incident from a direction conjugate with the reference light at the time of recording, a diffracted light conjugate with the white diffracted light 8 is obtained, and light distribution characteristics slightly different from the above are obtained. The holographic diffraction grating 6 of the present invention has diffracted light diffused, and exhibits very excellent characteristics when used for illumination light distribution and the like. The degree and directionality of the diffusion are determined by the characteristics of the directional diffusion plate 1 used at the time of recording, and the diffusion characteristics of the diffraction grating can be variously changed by selecting the characteristics of the directional diffusion plate. Also, unlike the conventional method using an imaging optical system, the size is not limited and the size can be easily increased. Holographic diffraction grating 6 of the present invention
When the original film 9 and the projection lens are installed on the optical path of the object light 4 at the time of the production as shown in FIG. 4 and an image is formed on the directional diffusion plate 1, an image hologram including image information and a pattern is formed. The method can be manufactured, and is extremely easy as a method of manufacturing an image hologram as compared with a conventional method of recording in two steps.

[0006]

According to the present invention, a holographic diffraction grating which can obtain white diffracted light upon incidence of white light, which has been conventionally difficult to manufacture, can be manufactured by one-step optical recording. In addition, a large-area diffraction grating can be manufactured because an imaging optical system or the like having a severe restriction on the aperture as in the related art is not used at the time of recording. According to the present invention, it has become possible to use a holographic diffraction grating for light distribution of artificial light or sunlight as a member having unprecedented excellent properties.

[0007]

[Brief description of the drawings]

FIG. 1 is a sketch showing a method for manufacturing a holographic diffraction grating of the present invention.

FIG. 2 is a sketch showing details of FIG. 1;

FIG. 3 is a sketch showing light diffracted by the holographic diffraction grating of the present invention.

FIG. 4 is a sketch showing a method for producing an image hologram including image information.

[Explanation of symbols]

 Reference Signs List 1 directional diffuser 2 holographic recording material 3 reference light 4 object light 5 object light diffused by diffuser 6 holographic diffraction grating of the present invention 7 white incident light 8 white diffracted light 9 original film 10 projection lens

Claims (2)

[Claims] 1. A directional diffusion plate having a diffusivity in a specific direction is placed in close contact with or close to a holographic recording material, and reference light is simultaneously incident from the transmission direction of the directional diffusion plate, and object light is simultaneously incident from the diffusion direction. , A reference light transmitted through the directional diffuser,
A method of manufacturing a holographic diffraction grating by recording interference fringes formed by interference of object light diffused by a directional diffusion plate on a holographic recording material. 2. A method for producing an image hologram including image information by spatially modulating object light incident on the directional diffusion plate according to claim 1 with image information.