JPS63306419A - Holographic recorder - Google Patents

Abstract

PURPOSE:To enable recording and reproducing the information of a drawing as a less-distorting three-dimensional hologram image in a relatively short period of time by projecting quasi-coherent light to a prescribed space modulator and interfering reference light with the exit light thereof, thereby obtaining the hologram. CONSTITUTION:This recorder consists of the quasi-coherent light source 11 such as laser, the space modulator 13 which is combined with a rough surface 12 of ground glass or the like in proximity thereto, a diver 16 which applies a phase distribution and density distribution to the space modulator 13, and a hologram dry plate 14. The two-dimensional phase distribution and density distribution are applied to the space modulator 13 by the driver 16 from the three-dimensional information inputted to a CAD, etc., and the three-dimensional stereoscopic drawing information is thereby obtd. The quasi-coherent light past the rough surface is projected thereto, by which the light wave flux equiv. to the light wave flux obtd. by projecting the quasi-coherent light 11 to a three- dimensional object is artificially obtd. This flux is recorded and reproduced as the hologram. The three-dimensional object image is thereby produced and observed.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to holographic recording and observation of three-dimensional shapes, and more specifically, to the recording and observation of three-dimensional shapes using holographic ink. It's something you get.

[Summary of the Invention] The present invention is a spatial transformation system that combines a quasi-coherent light source such as a laser and a rough surface such as ground glass in close proximity to each other. It consists of an IIB, a driver that gives a phase distribution and concentration distribution to the spatial modulator, and a hologram dry plate, and the driver gives a two-dimensional phase distribution and concentration distribution to the spatial modulator based on the three-dimensional information of the figure input to CAD etc. , thereby storing three-dimensional solid figure information, and by irradiating this with quasi-coherent light that has passed through a rough surface, a light wave packet equivalent to irradiating a quasi-coherent light onto a three-dimensional object is created, and this is used as a hologram. By recording and reproducing the object, it is possible to create and observe a three-dimensional image of the object from the information in the drawing without actually manufacturing the object.

[Conventional technology]

Conventionally, attempts have been made to observe three-dimensional images of objects without actually manufacturing them using holographic techniques based on information in drawings.

One example is the method of computer-generated holography, which divides the shape of an object obtained from a drawing into fixed pixels, calculates the complex amplitude distribution of light waves on a hologram dry plate for each pixel using diffraction theory, and calculates the complex amplitude distribution of light waves on a hologram dry plate. This method integrates the entire object and then determines the interference pattern with the reference wave, but the amount of calculation is unrealistic, and with the current computer performance, a satisfactory image cannot be obtained considering the calculation time. Not yet.

Another example is a multiplex hologram using a CRT display, as shown in Figure 2.
A figure 2 drawn on a T-display 1 viewed from a certain direction is copied onto a photographic plate 3 using an ordinary camera, and the image is repeatedly rotated little by little to correspond to each image on the CRT display. photographic plate 3a
, 3b... is created. Then, for the photographic images Vi3a, 3b, etc. showing images from each direction,
Object illumination light 4 is irradiated, interferes with reference light 5, and is recorded on a hologram dry plate 7. At this time, each photographic plate 3
A, 3b, . . . are provided with long tanzaku-shaped openings 6 in the direction of the rotation axis of the images whose positions are sequentially shifted, so that information from each angle is sequentially arranged on the hologram dry plate. The hologram 7 thus obtained has stereoscopic information in the direction of rotation of the image, and a pseudo-stereoscopic image can be observed.

[Problem that the invention seeks to solve]

In the first example above, as mentioned above, the amount of calculation is enormous and it takes a lot of time and cost to obtain a satisfactory image, so it is not as easy as actually manufacturing an article from a drawing. There is no benefit.

In the second example above, you can get a three-dimensional effect in the direction in which the image is rotated, but you cannot get a three-dimensional effect in the non-rotated direction. The amount of holograms created is so large that it is unrealistic. 1
Even if the object is rotated only in one direction, several hundred holograms must be taken to obtain a sufficient three-dimensional image, so it takes a relatively long time to create a hologram. moreover,
Because the rotated image is recorded on a single flat dry plate, distortion inevitably occurs in the image. There are problems such as being affected by distortion of the CRT screen.

[Means for solving problems]

In the present invention, a spatial modulator that can obtain at least a two-dimensional refractive index distribution with rough surfaces provided close to each other and a driver that drives the spatial modulator based on graphical information are provided, and quasi-coherent light is applied to the spatial modulator. The structure is such that a hologram is obtained by irradiating the hologram and interfering the emitted light with a reference light.

[Effect]

When a two-dimensional refractive index distribution is given to the spatial modulator by the driver based on the information in the drawing, the phase of the emitted light will have a lead or lag depending on the refractive index distribution, and this will change the shape of the actual object. will appear. Furthermore, since the object to be observed usually has a rough surface, a transparent rough surface such as ground glass is placed just in front of the spatial modulator, and the image formed by this is also an image formed by the rough surface. Therefore, it becomes observable.

〔Example〕

Hereinafter, embodiments of the present invention will be described based on the drawings.

FIG. 1 is a conceptual diagram showing an embodiment of the present invention. The spatial modulator 13 has electrodes arranged in a matrix and a driver 16.
By applying voltage to each matrix element, a refractive index distribution is formed.Currently, spatial modulators are made of ceramics or crystals with electro-optic effects such as PLZT, KDP, and BSO. is available. According to the graphical information input from the CAD terminal 17, the driver 16 applies voltage to each element of the spatial modulator 13 to create a refractive index distribution on the spatial modulator 13 based on the graphical information. When quasi-coherent light 11 such as a laser passes through the spatial modulator 13 through a rough surface 12 such as ground glass placed close to the spatial modulator 13, the light beam 11 changes according to the refractive index distribution of the spatial modulator 13. It can now be regarded as a collection of point light sources with a phase distribution,
This pseudo-corresponds to the reflected light when a real object is irradiated with coherent light. Therefore, the reference quasi-coherent light 15 is made to interfere with this light beam 11, and the hologram dry plate 14 is
When recorded, a three-dimensional image of the object represented in the drawing can be recorded in a pseudo manner. Therefore, by irradiating the recorded hologram dry plate 14 with the reference quasi-coherent light 15, a pseudo-stereoscopic image can be observed.

As mentioned above, there is a method of modulating the spatial modulator by arranging matrix electrodes on an electro-optic crystal or the like and driving each pixel with a voltage.
A method of placing a charge on an electro-optic crystal such as O, drawing image information onto the crystal using a laser scanner, etc., and canceling the charge by spontaneous polarization to create a refractive index distribution. A possible method is to arrange a conductive layer and draw a refractive index distribution using a laser scanner or the like, similar to the case of BSO.

Next, FIG. 3 shows a conceptual diagram of another embodiment of the present invention.The embodiment shown in FIG. 3 has the same basic operation as the embodiment shown in FIG. will be explained only. Until the light beam comes out from the spatial modulator,
This embodiment is completely similar to the embodiment shown in FIG. Here, currently available spatial modulators cannot provide a very large refractive index distribution, so objects with large undulations must be represented by spatially compressing information in the depth direction.

In such a case, a magnifying optical system 18 is installed behind the spatial modulator 13.
An enlarged image of the pseudo object created by the rough surface 12 and the spatial modulator 13 is created between the enlarging optical system 18 and the hologram dry plate 14, and the light beam and the reference quasi-coherent light 15 are
Normally, the vertical magnification of the enlarging optical system is the square of the horizontal magnification, so the image recorded as a hologram on the dry plate 14 is
The depth information in the optical axis direction given by the spatial modulator 13 is emphasized, and unevenness close to the original unevenness is expressed.

FIG. 4 is a conceptual diagram of an embodiment in which the same thing as the embodiment shown in FIG. Hologram dry plate 14 for observation
A magnifying optical system 19 is disposed between the camera and the observer 20 to magnify and observe the image. At this time, since the vertical magnification is larger than the horizontal magnification, it is possible to emphasize the depth information and observe the undulations close to the real thing.

〔Effect of the invention〕

As described above, the holographic ink recording device of the present invention allows information on drawings to be recorded and reproduced as a three-dimensional hologram image with little distortion at a relatively low cost and in a short time.

[Brief explanation of the drawing]

FIG. 1, FIG. 3, and FIG. 4 are conceptual diagrams each showing an embodiment of the holographic recording device of the present invention. FIG. 2 is a conceptual diagram showing an example of a conventional hologram device. 11...Incidence rate coherent light 12...Rough surface 13...Spatial modulator 14...Hologram dry plate 15...Reference quasi-coherent light 16...・Driver 18, 19...More than magnifying optical system

Claims (3)

[Claims] (1) A spatial modulator that can provide at least a two-dimensional refractive index distribution, a rough surface installed close to the spatial modulator, a driver that modulates the spatial modulator, and a quasi-coherent surface for generating a hologram. Consisting of a light source and a hologram dry plate, the driver modulates the refractive index distribution of the spatial modulator based on three-dimensional graphic information given as numerical information, and the image obtained by the rough surface and the spatial modulator is converted into a hologram. A holographic recording device characterized by recording as follows. (2) The holographic recording device according to claim 1, characterized in that an enlarging optical system is disposed between the spatial modulator and the hologram dry plate. (3) The holographic recording device according to claims 1 and 2, characterized in that a magnifying optical system is disposed between the hologram dry plate and the observer.