JPH04265986A - Method and device for exposing photosensitive material for hologram - Google Patents

Abstract

PURPOSE:To finish the exposure of a photosensitive material for a hologram in a short time. CONSTITUTION:A ray R2 for object light scans a photosensitive material 7 for a hologram through an acousto-optical element 11 and a vibrating scanner 13. Desired letters or a desired figure is drawn on the photosensitive material 7 by opening and closing a shutter 14 set just behind the element 11. The photosensitive material 7 is exposed by irradiation with a ray R1 for reference light diffused by an optical system 6 for light diffusion.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for exposing a photosensitive material for holograms.

0002

[Prior Art] Conventionally, when exposing a photosensitive material for holograms to create holograms with display patterns such as letters and figures, it is common to use a mold that corresponds to the shape of the actual letters and figures. It is.

That is, for example, a mold having a shape corresponding to a desired character or figure is made of a material that does not transmit light, such as paper or a board, and a laser beam diffused by an optical system such as a lens is applied to the mold. etc., and irradiates the hologram photosensitive material with the reflected light from the mold as an object beam. At the same time, a reference beam consisting of a laser beam generated from the same light source as the object beam and similarly diffused is applied onto the hologram photosensitive material. The object beam and reference beam were exposed to the holographic photosensitive material by interfering with each other on the holographic photosensitive material.

[0004] Another method is to form a mask with desired characters, figures, etc. cut out, cover the photosensitive material with the mask, and then irradiate the object light and irradiate the reference light from the opposite side. However, there is also a method in which the photosensitive material for hologram is exposed by causing the two to interfere.

[0005]

[Problems to be Solved by the Invention] However, in the conventional method, it takes time and effort to make molds of characters and figures. Moreover, one type of mold can only be used for one purpose, which is uneconomical.

Furthermore, since the laser beam for both the object beam and the reference beam is diffused by an optical system such as a lens system and irradiated onto the entire surface of the photosensitive material for holograms, the overall light intensity is reduced and a considerable amount of exposure is required. This method requires time, has a large manufacturing takt time, and is susceptible to vibrations.

[0007]

[Means for Solving the Problems] The present invention solves the above-mentioned problems, and provides a photosensitive material for holograms in which a plurality of light beams are caused to interfere with each other on the photosensitive material for holograms to form a holographic display pattern. A method for exposing a hologram to light, the method comprising: at least one of the light beams used for exposure being a light beam having a smaller spread angle than the display pattern; and scanning the light beam over a surface of a photosensitive material for holograms. The present invention provides a method for exposing a photosensitive material for holograms.

Having a smaller spread angle than the display pattern means that the light beam is small enough to display desired characters, figures, etc. by scanning the surface of the hologram photosensitive material with intensity changes. Generally, the size of the holographic photosensitive material is approximately 1/10 to 1/10 the size of the characters, figures, etc. on the surface of the hologram photosensitive material.

For this purpose, the generated laser light may be used as it is, or it may be slightly diffused by an optical system such as an appropriate lens.

As the scanning flat plate, in addition to a polygon mirror, a laser scanner such as a galvano scanner that rotates the mirror surface by a magnetic field is preferably used.

In reality, the object light is irradiated while adjusting the light beam intensity so as to draw desired characters, figures, etc. For example, during scanning, when the light beam comes on a character to be drawn on the hologram photosensitive material, the light beam is turned off, and in other cases, the light beam is turned on.

0012

[Example] The present invention will be explained below according to an example.

[Embodiment 1] FIG. 1 shows an example of the configuration of the present invention when creating a reflection hologram.

After being reflected by a mirror 1, the laser beam R from the laser device is split into a reference beam R1 and an object beam R2 by a beam splitter such as a half mirror 2. Since R1 is used after being diffused by a lens system, the intensity ratio of R1 and R2 is R1 /R2
= approximately 100 to 10,000. R1
After being reflected by a mirror 5, the light passes through a light diffusion optical system 6 such as an objective lens or a spatial filter, and then is irradiated onto a hologram photosensitive material 7 with a widening angle.

On the other hand, R2 is reflected by the mirrors 3 and 4 and then enters a deflector such as the acousto-optic element 11. The deflection signal from the controller 8 passes through the oscillator 9 and the amplifier 10 to drive the acousto-optic element 11, and the laser beam R2' that has passed through the acousto-optic element 11 oscillates within the range of R2u and R2d (parallel to the plane of the paper). The signal from the controller 8 also operates a scanner driver 12 for driving a vibration scanner 13 such as a galvano scanner. Then, the vibration scanner 13 moves R2 in the direction perpendicular to the paper surface.
” to be scanned.

Immediately after the acousto-optic element 11, a shutter 14 is placed, and by turning it on and off, desired characters, figures, etc. are drawn on the hologram photosensitive material 7.

The shutter 14 may be configured to allow only a light image in a desired direction to pass through by driving a mirror at an appropriate timing, or may change the light transmittance at an appropriate timing. It may be something like this.

In the present invention, since the acousto-optic element 11 sweeps the laser beam R2 horizontally and the vibration scanner 13 scans it vertically, the movement of the laser beam in the horizontal and vertical directions is controlled by the controller 8. By controlling the shutter 14 and driving the shutter 14 at appropriate timing, arbitrary characters or figures can be drawn on the hologram photosensitive material 7. If this laser beam is used as an object beam and the reference beam R1 diffused by the light diffusing optical system 6 is used as a reference beam, interference fringes are created by the interference of the two beams, and hologram recording can be performed.

At the time of reproduction, a reproduction light source may be placed at the position of the light diffusion optical system 6.

[Embodiment 2] Another embodiment is shown in FIG. In contrast to the first embodiment, in which a reflection hologram was created, this example uses a transmission hologram creation method. A laser beam R from the laser device is split by a half mirror 2 into an object beam R3 and a reference beam R4.

Regarding R4, after reflecting from mirror 3,
R3 and R4 enter a deflector consisting of acousto-optic elements 11 and 11'. As in the case of the first embodiment, the oscillator 9,
The signal passed through the amplifier 10 drives the acousto-optic elements 11, 11', and deflects R3 and R4 in the horizontal direction (parallel to the plane of the paper). Further, the laser beams R3' and R4' that have passed through the acousto-optic elements 11 and 11' are converted into laser beams R3' and R4' by a signal from the controller 8, which drives the scanner driver 12 and the vibration scanner 13, as in the case of the first embodiment.
Let 3' and R4' be laser beams R3'' and R4'' that vibrate in the horizontal direction (perpendicular to the plane of the paper). In this example R
It is preferable to control the deflection of 11, 11' and 13 so that 3'' and R4'' always overlap on the hologram 7. During reproduction, a reproduction illumination light source is placed at position 11 or 11'.

In this embodiment, as in the first embodiment, if there is a shutter 14 immediately after the acousto-optic element 11, by turning it on and off, desired characters, figures, etc. are transferred to the hologram photosensitive material 7. Draw on top.

A polygon mirror may be used instead of the acousto-optic elements 11 and 11' in the first and second embodiments. In this case, a polygon driver is used instead of 9 and 10. This is advantageous for exposure when the scanning angle is large.

[0024]

[Effects of the Invention] In the present invention, since the light beam is scanned on the line to be exposed (drawn), the laser power can be concentrated, and the work can be completed in a shorter time than when the entire hologram surface is exposed. Therefore, it is possible to reduce the influence of vibration of the optical system, which is the biggest problem when creating a hologram. Furthermore, since the laser beam is scanned by an electrical signal and the drawing shutter is turned on and off, it is possible to easily create figures that are difficult to make as molds.

[Brief explanation of the drawing]

[Figure 1] Conceptual diagram showing an embodiment of the present invention

[Figure 2]
Conceptual diagram showing other embodiments of the present invention

[Explanation of symbols]

1, 3, 4, 5: Mirror 2: Half mirror 6
: Optical system for light diffusion 7
: Photosensitive material for hologram 8
: Controller 9 : Oscillator 10 : Amplifier 11, 11'
:Acousto-optic element

Claims (2)

[Claims] 1. A method of exposing a photosensitive material for holograms by causing a plurality of light beams to interfere on the photosensitive material for holograms to form a holographic display pattern, the method comprising: A method for exposing a photosensitive material for holograms, characterized in that the exposure is carried out using a light beam having a smaller spread angle than the display pattern, and the light beam is scanned on the surface of the photosensitive material for holograms. 2. An apparatus for exposing a photosensitive material for holograms, comprising: a light beam generating means for forming a light beam having a smaller spread angle than a display pattern as a light beam used for exposure; 1. An exposure apparatus for a photosensitive material for holograms, comprising a light beam deflecting means for scanning a surface of the photosensitive material for holograms.