JP2002341732A - Device for manufacturing holographic stereogram and shutter device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably record on a hologram recording medium by exposure without adding vibration. SOLUTION: The manufacturing zone 13 of a holographic stereogram includes as the incident optical system, a laser light source 21 which is a semiconductor excited YAG laser device emitting laser light of high coherency at 532 nm wavelength and 400 mW output power, a shutter mechanism 22 disposed on the optical axis of the laser light L1 from the laser light source 21 to pass the laser light L1 to the succeeding stage or to block the light, and a half mirror 23 to split the laser light L1 into object light L2 and reference light L3. The shutter mechanism 22 is equipped with a mechanical shutter 40 which mechanically opens or closes to pass or block the laser light L1, a driving voltage supply part 41 to supply pulsed high frequency voltage, an acoustooptic modulator 42 which modulates the intensity of the first-order diffracted light and zero-order light by using the acoustooptic effect, and a shielding part 43 to block the first-order diffracted light not used for exposure recording.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a holographic stereogram producing apparatus for producing a holographic stereogram and a shutter device thereof.

[0002]

2. Description of the Related Art A holographic stereogram is obtained, for example, by using a large number of images obtained by sequentially photographing a subject from different observation points as original images, and forming these images on a single hologram recording medium in the form of strips or dots. It is manufactured by sequentially exposing and recording as an element hologram.

FIG. 6A shows a holographic stereogram producing section 200 having an optical system of a holographic stereogram producing apparatus for producing a holographic stereogram. The holographic stereogram producing section 200 has a single-wavelength laser light L20 having good coherence.
1, a shutter mechanism 202 that is mechanically opened / closed by a control signal output from a control computer (not shown) to enter and block the emitted laser light L201, A half mirror 203 for dividing the laser beam L201 into an object beam L202 and a reference beam L203, and optical components 204, 205, 206, and 20 constituting an optical system of the object beam L202.
7, 208, 209 and display 210, and reference light L20.
Optical components 211, 212, and 213 that constitute the optical system 3
And a recording medium feeding mechanism 214 for intermittently driving the hologram recording medium 215 on which the object light L202 and the reference light L203 converge.

The optical system of the object light L202 is, specifically,
Mirrors 204 sequentially arranged from the input side thereof along the optical axis, a spatial filter 205 for isotropically expanding the object light L202, and an expanded object light L20
A collimator lens 206 that makes 2 parallel light;
A projection lens 207 that guides the object light 202 to a cylindrical lens 208;
5 and a mask 209 having a strip-shaped opening and having the light passing through the opening incident on the hologram recording medium 215. The display 210 is constituted by a transmissive liquid crystal panel,
It is arranged between the collimator lens 206 and the projection lens 207. The display 210 displays image data output from an image processing unit (not shown).

The optical system of the reference light L203 is, specifically,
A spatial filter 211 that is sequentially arranged from its input side along the optical axis and expands the reference light L203 in a one-dimensional direction, a collimator lens 212 that makes the expanded reference light L203 a parallel light, and a reference light L203. Mirror 213 for reflecting and guiding to hologram recording medium 215
And

The hologram recording medium 215 is made of a so-called dry process film as a photosensitive material.
As shown in FIG. 6B, the recording medium is held by a recording medium feeding mechanism 214. When the recording medium feeding mechanism 214 is driven, it is intermittently driven to run in a direction indicated by an arrow aa.

The laser beam L201 is emitted from the laser light source 201 as shown in FIG.
02 and enters the half mirror 203, where the object light L202 and the reference light L2 are reflected by the half mirror 203.
03.

[0008] The object light L202 is transmitted through the spatial filter 205 and the collimator lens 206 to the display 21.
At the same time, the light is incident on the display device 210 and image-modulated in accordance with the displayed element image when transmitted through the display 210. The image-modulated object light L202 is incident on the hologram recording medium 215 via the projection lens 207, the cylindrical lens 208, and the opening of the mask 209. Also,
The reference light L203 is incident on the hologram recording medium 215 via the optical system of the spatial filter 211, the collimator lens 212, and the mirror 213.

Therefore, the hologram recording medium 215
, Interference fringes generated by interference between the object light L202 and the reference light L203, which are image-modulated by the image displayed on the display 210, are sequentially exposed and recorded in the form of strips or dots as element holograms.

The holographic stereogram produced by the holographic stereogram producing section 200 is recorded as a part of each elementary hologram when the observer views the holographic stereogram from one position with one eye. When a set of image information is identified as a two-dimensional image and viewed with one eye from another position different from this position, the image information recorded as another part of each element hologram is displayed. The aggregate is identified as another two-dimensional image. Therefore, when the observer views the holographic stereogram with both eyes, the exposure recorded image is recognized as a three-dimensional image by the parallax of the left and right eyes.

As an application to which such a holographic stereogram is applied, for example, “Ak
ira Shirakura, Nobuhiro Kihara and Shigeyuki Baba,
“Instant holographic portrait printing system”,
Proceeding of SPIE, Vol. 3293, pp. 246-253, Jan. 1
998, "Kihara, Shirakura, Baba:" High-speed hologram portrait print system ", 3D image conference 1998, July 1998, etc., to generate a parallax image sequence by photographing a subject. Photographing device and holographic stereogram producing unit 2 described above
For example, there is a printer system in which a holographic stereogram or a hologram such as 00 is combined with a printing device that outputs a hologram as a printed matter. Such a printer system can provide services from photographing a subject to printing a photographing result at the same place.

[0012]

By the way, the holographic stereogram producing section 200 described above is used as the hologram recording medium 215 in view of the fact that the predetermined processing performed after the exposure recording of the element hologram is easy. Often a dry process film is used. In this case, the hologram recording medium 215 is usually
After one holographic stereogram image is exposed and recorded by the holographic stereogram producing unit 200, the holographic stereogram image is cut as one unit and subjected to a predetermined fixing process.

However, the dry process film used also as such a hologram recording medium 215 usually has a structure in which a plurality of very thin sheets are stacked, and when a slight vibration is applied, the dry process film becomes stable. Exposure is not recorded. The above-described shutter mechanism 202
Since the shutter mechanism 202 mechanically opens and closes, a minute vibration caused by the shutter mechanism 202 is applied to the hologram recording medium 215, which may hinder stable exposure recording.

On the other hand, the holographic stereogram producing section 200 is provided with a vibration removing mechanism for removing vibration, but this increases the size of the entire holographic stereogram producing section 200 and deteriorates operability. Inviting.

Further, since the shutter mechanism 202 mechanically opens and closes, it has a short life and is not suitable for long-term continuous exposure.

Further, when producing a holographic stereogram in which the image information obtained from each observation point is more continuously and smoothly observed, many element holograms are required, and the size of the holographic stereogram is further increased. The larger is, the more elementary holograms are required and the more time it takes to produce a holographic stereogram. Therefore, in order to reduce the time for producing a holographic stereogram, the shutter mechanism 202 needs to open and close quickly to shorten the exposure recording time, and to frequently open and close.
However, it is difficult for the shutter mechanism 202 to quickly open and close the shutter mechanism 202, and the shutter mechanism 202 causes vibration to the hologram recording medium 215 due to frequent opening and closing operations.

Further, when the element hologram is not exposed and recorded, the shutter mechanism 202 reliably outputs the laser beam L2.
01 must be blocked.

Accordingly, the present invention has been proposed in view of the above-described circumstances, and has been described as a holographic stereogram producing apparatus capable of performing stable exposure recording without giving vibration to the hologram recording medium 215. It is an object to provide the shutter device.

[0019]

In order to solve the above-mentioned problems, a holographic stereogram producing apparatus according to the present invention displays a laser light source for emitting laser light and a plurality of image information including parallax information. Image information display control means, a shutter means for blocking and transmitting the laser light emitted from the laser light source, and a laser light transmitted through the shutter means for branching each image information displayed by the image information display control means. The transmitted and image-modulated object light is incident on one surface of the hologram recording medium, and the reference light having coherence with the object light is incident on the other surface or one surface of the hologram recording medium. Recording means for sequentially exposing and recording interference fringes generated by the object light and the reference light as elementary holograms on a hologram recording medium; Acousto-optic means for influencing the characteristics of the laser light depending on the result and intercepting and transmitting the laser light by modulating the intensity of the laser light, and located before or after the acousto-optic means to perform a mechanical opening / closing operation Mechanical shutter means for blocking and transmitting the laser light.

In this holographic stereogram producing apparatus, the acousto-optic means affects the characteristics of the laser light emitted from the laser light source by the acousto-optic effect, and intercepts and transmits the laser light by modulating the intensity of the laser light. The mechanical shutter means is positioned before or after the acousto-optic means, cuts off and transmits the laser light by a mechanical opening / closing operation, branches the laser light transmitted by the recording means, and controls the image information display control means. The object light modulated by transmitting the image information including the parallax information displayed by the hologram recording medium is incident on one surface of the hologram recording medium, and the reference light having coherence with the object light is transmitted to the other side of the hologram recording medium. And the interference fringes generated by the object light and the reference light are used as element holograms on the hologram recording medium. To the next exposure recording.

In order to solve the above-mentioned problems, a shutter device according to the present invention splits a laser beam emitted from a laser light source and transmits each image information among a plurality of pieces of image information including parallax information. The image-modulated object light is incident on one surface of the hologram recording medium, and the reference light having coherence with respect to the object light is incident on the other surface or one surface of the hologram recording medium, Used in a holographic stereogram producing apparatus for sequentially exposing and recording interference fringes generated by object light and reference light as an element hologram on a hologram recording medium, in a shutter device for blocking and transmitting laser light emitted from a laser light source, Acousto-optic means for influencing the characteristics of the laser light by means of the acousto-optic effect, and intercepting and transmitting the laser light by modulating the intensity of the laser light; It located before or after the acoustic optical means, and a mechanical shutter means for blocking and transmitting the laser beam by performing a mechanical opening and closing operations.

In this shutter device, the acousto-optic means affects the characteristics of the laser light emitted from the laser light source by an acousto-optic effect, and modulates the intensity of the laser light to cut off and transmit the laser light. The shutter means is positioned before or after the acousto-optic means, and the laser light is cut off and transmitted by mechanical opening / closing operation, and the interference fringes generated by the transmitted laser light are sequentially exposed and recorded on the hologram recording medium as element holograms. Holographic stereogram producing apparatus.

[0023]

Embodiments of the present invention will be described below in detail with reference to the drawings. A holographic stereogram producing apparatus according to an embodiment of the present invention produces a holographic stereogram having lateral parallax information by exposing and recording a plurality of strip-shaped element holograms on one hologram recording medium. As a holographic stereogram producing apparatus, a holographic stereogram having horizontal and vertical parallax information by exposing and recording a plurality of dot-like element holograms on one hologram recording medium is described. It is needless to say that a gram may be produced.

As shown in FIG. 1, a holographic stereogram producing apparatus 10 exposes and records a holographic stereogram image on a hologram recording medium 3 made of a so-called dry process film as a photosensitive material. is there. The holographic stereogram producing apparatus 10 includes an image data processing unit 11 for processing image data to be subjected to exposure recording, a control computer 12 for controlling the holographic stereogram producing apparatus 10 as a whole, and a holographic stereogram producing apparatus. A holographic stereogram producing unit 13 having an optical system for production.

The image data processing section 11 has at least an image processing computer 14 and a storage device 15, and includes disparity information supplied from the disparity image sequence imaging device 1 having, for example, a multi-view camera or a mobile camera. A parallax image data sequence D3 is generated based on image data such as captured image data D1 and computer image data D2 including parallax information generated by the image data generating computer 2.

The captured image data D1 is, for example, a plurality of image data obtained by simultaneous photographing with a multi-lens camera or continuous photographing with a mobile camera. Parallax information is included. The computer image data D2 is, for example, a CAD (Computer Aided Design) or a CG (Computer Graph).
phics), parallax information is included between the respective image data constituting the computer image data D2.

The image data processing section 11 applies a predetermined image processing for holographic stereogram to the parallax image data sequence D3 based on the captured image data D1 and / or the computer image data D2 by the image processing computer 14. Hologram image data D4
Generate The hologram image data D4 is temporarily stored in a storage device 15 such as a memory or a hard disk device. The image data processing unit 11, as described later,
When exposing and recording the element hologram images on the hologram recording medium 3, the element hologram image data D5 for each image is sequentially read from the hologram image data D4 stored in the storage device 15, and these element hologram image data D5 are read. To the control computer 12.

The control computer 12 controls the holographic stereogram producing unit 13 to control the element hologram image data D supplied from the image data processing unit 11.
5 are sequentially exposed and recorded as strip-shaped element holograms on the hologram recording medium 3 provided in a part of the holographic stereogram producing section 13. At this time, the control computer 12 controls the operation of each mechanism of the holographic stereogram producing unit 13 as described later.

Holographic stereogram producing unit 1
Reference numeral 3 denotes a structure in which each member constituting the optical system is disposed and supported on a support substrate (optical surface plate) (not shown), and the support substrate is supported by a device housing via a damper (not shown). Holographic stereogram production unit 13
Has an incident optical system, an object optical system, and a reference optical system as optical systems for producing a holographic stereogram. The holographic stereogram producing device 1
Reference numeral 0 uses the hologram recording medium 3 which is a photosensitive material, so that the device housing has a structure that retains at least the light shielding properties of the optical system.

Holographic stereogram producing unit 1
Reference numeral 3 denotes a laser light source 21 for emitting a laser beam of a predetermined wavelength as an incident optical system, and a laser light disposed on the optical axis of the laser light L1 from the laser light source 21 as shown in FIG. A shutter mechanism 22 for causing the light L1 to enter or block the subsequent stage; and a laser beam L1 for the object light L2 and the reference light L.
And a half mirror 23 which is divided into three.

The laser light source 21 has a wavelength of 532n, for example.
m, an output of 400 mW, and a semiconductor-pumped YAG laser device that emits laser light L1 having good coherence.

The details of the shutter mechanism 22 will be described later.
From the laser light L1 emitted from the laser light source 21, a first-order diffracted light diffracted under predetermined conditions and a zero-order light transmitted without being diffracted under predetermined conditions are generated, and control is performed in accordance with the output timing of the element hologram image data D5. In order to periodically perform intensity modulation of the first-order diffracted light and the zero-order light according to control by the control signal C1 output from the computer, and to use either the first-order diffracted light or the zero-order light for exposure recording of the element hologram. The light is incident on the subsequent stage, and the other light is shielded because it is not used for exposure recording of the element hologram. Here, a description will be given assuming that the zero-order light is used for exposure recording of the element hologram. That is, the shutter mechanism 22 causes the zero-order light to enter the subsequent stage,
Next-order diffracted light is blocked. Further, when the production of the holographic stereogram is completely completed, the shutter mechanism 22 completely blocks the laser beam L1.

The half mirror 23 splits the incident zero-order light into transmitted light and reflected light. As for the zero-order light, transmitted light is used as the above-described object light L2, while reflected light is used as the reference light L3. These object light L2 and reference light L
3 is incident on the object optical system or reference optical system provided at the subsequent stage, respectively.

Although not shown, the incident optical system has 0
The traveling direction of the next light is appropriately changed so that the object light L2 and the reference light L
A mirror or the like may be provided for the purpose of making the optical path length equal to that of the mirror 3 or the like.

As shown in FIGS. 2A and 2B, the holographic stereogram producing section 13
The object optical system includes optical components such as a mirror 24, a spatial filter 25, a collimator lens 26, a projection lens 27, a cylindrical lens 28, a mask 29, and the like. They are arranged sequentially.

The mirror 24 reflects the object light L2 transmitted through the half mirror 23. The object light L2 reflected by the mirror 24 enters the spatial filter 25.

The spatial filter 25 is configured by combining a convex lens and a pinhole, and
The object light L2 reflected by 4 is isotropically enlarged corresponding to the display surface width of the transmission type liquid crystal display 30 described later.

The collimator lens 26 converts the object light L2 enlarged by the spatial filter 25 into parallel light and guides the parallel light to the transmission type liquid crystal display 30.

The projection lens 27 projects the object light L2 onto the cylindrical lens 28.

The cylindrical lens 28 converges the collimated object light L2 in the horizontal direction.

The mask 29 has a strip-shaped opening, and of the object light L 2 condensed by the cylindrical lens 28, the one that has passed through the opening is incident on the hologram recording medium 3.

In the object optical system, a transmission type liquid crystal display 30 is disposed between the collimator lens 26 and the projection lens 27. In the transmissive liquid crystal display 30,
The element hologram images are sequentially displayed based on the element hologram image data D5 supplied from the control computer 12. The control computer 12 responds to the output timing of the element hologram image data D5 by
The drive signal C2 is supplied to a recording medium feeding mechanism 35 for the hologram recording medium 3 described later, and the operation of the mechanism is controlled, thereby controlling the feeding operation of the hologram recording medium 3.

In such an object optical system, the object light L2 in the state of a point light source split and incident from the incident optical system is used.
Is enlarged by the spatial filter 25 and is incident on the collimator lens 26 to be converted into parallel light. Further, in the object optical system, the object light L2 incident on the transmission type liquid crystal display 30 via the collimator lens 26 is image-modulated according to the element hologram image displayed on the transmission type liquid crystal display 30. At the same time, the light is incident on a cylindrical lens 28 via a projection lens 27. Then, while the shutter mechanism 22 causes the zero-order light to enter according to the control by the control signal C1, the object optical system applies the image-modulated object light L2 through the opening of the mask 29 to the hologram recording medium 3. And the exposure hologram is recorded corresponding to the element hologram image. At this time,
The object light L2 is incident on the hologram recording medium 3 such that the optical axis is substantially perpendicular to the main surface of the hologram recording medium 3.

Further, the holographic stereogram producing section 13 has a spatial filter 31, a collimator lens 32 and a mirror 33 as a reference optical system.
These optical components are sequentially arranged from the input side along the optical axis.

The spatial filter 31 is composed of a combination of a cylindrical lens and a slit. The spatial filter 31 converts the reference light L3 reflected and divided by the half mirror 23 into a predetermined width, specifically, the display surface of the transmission type liquid crystal display 30. Enlarge in the one-dimensional direction corresponding to the width.

The collimator lens 32 converts the reference light L3 enlarged by the spatial filter 31 into parallel light.

The mirror 33 reflects the reference light L3 and makes the reference light L3 incident on the rear of the hologram recording medium 3.

The holographic stereogram producing section 13 having such an optical system includes an object optical system that is an optical system through which the object light L2 split by the half mirror 23 passes, and an optical system through which the reference light L3 passes. The optical path length with a certain reference optical system is configured to be almost the same. Therefore, the holographic stereogram producing unit 13 can produce a holographic stereogram in which the coherence between the object light L2 and the reference light L3 is improved and a clearer reproduced image can be obtained.

The holographic stereogram producing apparatus 10 is provided with a recording medium feeding mechanism 35 for intermittently feeding the hologram recording medium 3 by one element hologram in a direction indicated by an arrow a in FIG. 2B.

The recording medium feeding mechanism 35 intermittently drives the hologram recording medium 3 based on the drive signal C2 supplied from the control computer 12. The recording medium feeding mechanism 35 blocks the first-order diffracted light that is not used for exposure recording of the element hologram in accordance with the control by the control signal C1 supplied by the shutter mechanism 22 in conjunction with the operation of the recording medium feeding mechanism 35. During the operation, the hologram recording medium 3 is positioned at the position where the next element hologram is to be exposed and recorded.
To move.

In such a holographic stereogram producing apparatus 10, a drive signal C2 corresponding to one element hologram is supplied from the control computer 12 to the recording medium feeding mechanism 35 every time exposure recording of one element image is completed. As a result, the hologram recording medium 3 is driven to travel along the traveling path by an amount corresponding to one element hologram, and is stopped corresponding to the unexposed portion at the opening of the mask 29. The holographic stereogram producing device 1
0 is configured so that the vibration generated in the hologram recording medium 3 due to the running operation of the hologram recording medium 3 is immediately stopped. Here, the hologram recording medium 3 is made of a long dry process film, and is wound around a supply roll rotatably provided inside a film cartridge, for example, the whole of which is held in a light-shielding state, although not shown. ing. When the film cartridge is loaded into the holographic stereogram producing device 10, the hologram recording medium 3 is fed into the holographic stereogram producing device 10, and is driven to travel on the traveling path by the recording medium feeding mechanism 35. .

In the holographic stereogram producing apparatus 10, the shutter mechanism 22 in this state causes the zero-order light to enter, and the object light L2 and the reference light L3 image-modulated from the front and back surfaces of the hologram recording medium 3 from the front and back surfaces. Is incident on the hologram recording medium 3, and exposure fringes corresponding to the interference hologram image are recorded. When the exposure recording of the one element image is completed, the drive signal C2 is supplied from the control computer 12 to the recording medium feeding mechanism 35, and the holographic stereogram producing apparatus 10
Is immediately driven to travel by a predetermined amount and stopped.

The holographic stereogram producing apparatus 10 sequentially performs the above operation, thereby sequentially exposing and recording a plurality of holographic stereogram images on the long hologram recording medium 3 to record one holographic stereogram image. A holographic stereogram on which a holographic stereogram image is recorded by exposure is prepared.

Next, the schematic structure of the above-described shutter mechanism 22 will be described in detail with reference to FIG. The shutter mechanism 22 converts the laser light emitted from the laser light source 21
Generates a first-order diffracted light diffracted under predetermined conditions and a zero-order light transmitted without being diffracted, and is controlled by a control signal C1 output from a control computer in accordance with the output timing of the element hologram image data D5. And periodically modulates the intensity of the first-order diffracted light and the zero-order light to make the 0th-order light used for exposure recording of the element hologram incident on the subsequent stage, and blocks the first-order diffracted light not used for the exposure recording of the element hologram. .

The shutter mechanism 22 mechanically opens and closes to mechanically open and close the laser beam L 1, a driving voltage supply unit 41 for supplying a pulsed high-frequency voltage, and an acousto-optic effect. An acousto-optic modulator that modulates the intensity of the first-order diffracted light and zero-order light
Optic Modulator: described as AOM) 42 and a light-shielding portion 43 for shielding primary diffracted light not used for exposure recording.

The mechanical shutter 40 is located before or after the AOM 42, emits the laser beam L1 when the production of the holographic stereogram is started, and when the production of the holographic stereogram is completed. Laser light L1 is completely cut off.

The drive voltage supply section 41 receives the control signal C1 output from the control computer 12 in accordance with the output timing of the element hologram image data D5, and generates a pulsed high-frequency voltage in accordance with the control signal C1. AOM4
Supply to 2.

The AOM 42 includes an acousto-optic medium 44 and a piezoelectric element 45 (transducer) adhered to the acousto-optic medium 44. The piezoelectric element 45 applies ultrasonic waves to the acousto-optic medium 44 in a pulsed manner by a high-frequency voltage supplied from the drive voltage supply unit 41 in a pulsed manner.
The acousto-optic medium 44 is a crystal having a large refractive index, and causes a change in the refractive index with a cycle of the wavelength of the ultrasonic wave applied from the piezoelectric element 45.

Here, the acousto-optic effect used when the AOM 42 modulates the intensity of the first-order diffracted light and the zero-order light will be described. The acousto-optic effect means that when an ultrasonic wave is applied to the acousto-optic medium 44 by the piezoelectric element 45, the photoelastic effect causes a change in the refractive index in the acousto-optic medium 44 according to the wavelength and amplitude of the ultrasound, and the refractive index The change causes the acousto-optic medium 44 to act as a diffraction grating, and the laser light L1 incident on the acousto-optic medium 44 undergoes diffraction, and the intensity and direction of the diffracted light change according to the intensity and frequency of the ultrasonic wave. That is.

[0060] That is, from the laser light L1 incident at a predetermined angle theta _B in AOM42, the ultrasonic waves are applied, the 0 and order light transmitted without being diffracted and first-order diffracted light diffracted at an angle theta _B Occurs. Further, the first-order diffracted light and the zero-order light are applied with ultrasonic waves in a pulse,
The intensity modulation is performed periodically according to the intensity modulation of the ultrasonic wave. That is, the AOM 42 periodically performs the intensity modulation of the first-order diffracted light and the zero-order light according to the control by the control signal C1.

The light shielding section 43 shields the primary diffracted light not used for exposure recording of the element hologram from leaking into the optical system.

The shutter mechanism 22 constructed as described above
Is designed to guide the zero-order light, out of the zero-order light and the first-order diffracted light, of which the intensity is periodically modulated by the ultrasonic waves applied in a pulsed manner in accordance with the control by the control signal C1 to the subsequent optical system. As a result, the zero-order light used for the exposure recording of the element hologram is transmitted and blocked. At this time, the shutter mechanism 22 shields the first-order diffracted light not used for exposure recording of the element hologram by the light shielding unit 43 so as not to leak to the subsequent optical system. Further, the shutter mechanism 22
Irradiates the laser beam L1 when the production of the holographic stereogram is started, and completely shuts off the laser beam L1 when the production of the holographic stereogram is completed.

Next, the operating principle of the AOM 42 used in the above-described shutter mechanism 22 will be described with reference to FIG. The piezoelectric element 45 is adhered to the acousto-optic medium 44, and the piezoelectric element 45 applies ultrasonic waves in a pulsed manner to the acousto-optic medium 44 by a high-frequency voltage supplied from the drive voltage supply unit 41 in a pulsed manner.
When applied to the acousto-optic medium 44, a periodic change in the refractive index occurs in the acousto-optic medium 44 due to the photoelastic effect, and the acousto-optic medium 44 acts as a diffraction grating due to the change in the refractive index. When the condition is satisfied, an efficient diffraction effect is exhibited.

Here, the interaction between the laser beam L1 and the ultrasonic wave
Distance is L, wavelength of light in vacuum is λ _σ, Acousto-optic medium 4
V is the sound speed of 4 and f is the ultrasonic frequency._α, Acousto-optic medium 44
Let n be the refractive index of
Egg diffraction occurs.

[0065]

(Equation 1)

Under the condition in which the Bragg diffraction occurs, a zero-order light that is not diffracted and a first-order diffracted light that is diffracted are obtained. Here, 1 is the direction theta _B order diffracted light, the equation (2).

[0067]

(Equation 2)

In Bragg diffraction, the incident angle of incident light is θ _B
, The highest diffraction efficiency is obtained. Further, the intensity I1 of the _first-order diffracted light is proportional to the ultrasonic power Pa of the acousto-optic medium 44, and is expressed by Expression (3).

[0069]

(Equation 3)

In the equation (3), Me is a constant determined by the physical property value of the acousto-optic medium 44. The larger this value is, the higher the refraction efficiency is obtained. I have. Also, _{K 1} is a constant of the piezoelectric element 45. As described above, the AOM 42 modulates the intensity of the first-order diffracted light according to the change in the ultrasonic power Pa, that is, the intensity modulation of the ultrasonic wave.

In producing a holographic stereogram, it is necessary to adjust the position of the AOM so that the above-described Bragg diffraction occurs when the laser beam L1 enters the AOM constituting the shutter mechanism.

The position adjusting device 50 for adjusting the position of the AOM 42 will be described with reference to FIG. The position adjustment device 50 mounts the AOM 42 and changes the angle formed between the optical axis of the laser beam L1 incident on the AOM 42 and the AOM 42, and mounts the goniometer 51 and performs circular motion in the forward and reverse directions. It includes a rotating stage 52, an oscilloscope 53 for displaying the waveform of a pulse generated from the drive voltage supply unit 41 shown in FIG. 3, and a photosensor 54 for measuring the intensity of the first-order diffracted light generated by passing through the AOM 42. .

Here, the drive voltage supply section 41 includes a pulse function generator 55 for generating a pulse of a predetermined frequency, and a DC power supply 56 for supplying a DC voltage.
And an AOM driver 57 that controls a DC voltage according to the pulse. The pulse function generator 55 generates a pulse of a predetermined frequency,
Output to the driver 57 and the oscilloscope 53. The DC power supply 56 supplies a DC voltage to the AOM driver 57. The AOM driver 57 includes a pulse output from the pulse function generator 55 and a DC power supply 56
And supplies the DC voltage to the AOM 42 according to the pulse.

The gonio stage 51 includes a mechanical shutter 40.
When the optical axis of the laser beam L1 that has passed through the AOM 42 and entered the AOM 42 is the x-axis, the surface on which the AOM 42 is mounted is the xy plane, and the axis orthogonal to the xy plane is the z-axis, Therefore, the xy plane is inclined at an angle φ in the x direction with respect to the z axis, and the xy plane becomes z
By inclining at an angle θ in the y direction with respect to the axis, AOM42
Adjust the position of.

The rotation stage 52 adjusts the position of the AOM 42 by making a circular motion in the forward and reverse directions and rotating by an angle ω.

The oscilloscope 53 receives the pulse output from the pulse function generator 55, and displays the waveform of the pulse actually sent to the AOM driver 57.

The photo sensor 54 receives the first-order diffracted light generated by passing through the AOM 42 and measures its intensity.

The user adjusts the position of the AOM 42 by using the position adjusting device 50 configured as described above and performing the following procedure. First, the user places the gonio stage 51 on the rotating stage 52, and further places the AOM 42 on the gonio stage 51. Next, the user operates the mechanical shutter 40 to open the laser beam L1.
Is incident on the AOM 42.

Next, the user adjusts the AOM driver 57 to transmit a pulse of a predetermined frequency to the AOM 42.
The pulse is actually transmitted to the AOM 42 by the pulse function generator 55 connected to the oscilloscope 53, and is monitored by the oscilloscope 53 connected to the pulse function generator 55.

Next, the user sends the laser light L1 to the AOM4
The AOM 42 is finely adjusted by using the operation units 51a and 51b of the gonio stage 51 and the rotary stage 52 so that Bragg diffraction occurs when the laser beam L1 is incident on the laser beam L1, that is, the incident angle of the laser beam L1 is adjusted to the Bragg angle. Make adjustments. At this time, the user measures the intensity of the first-order diffracted light using the photo sensor 54, and operates the gonio stage 51 and the rotary stage 52 so that the intensity of the measured first-order diffracted light is maximized. Adjust the position.

The reason that the AOM 42 is adjusted so that the intensity of the first-order diffracted light measured by the photosensor 54 is maximized is that the hologram recording medium 3 is intermittently interposed in order to sequentially expose and record element holograms. This is to ensure that the intensity of the zero-order light is minimized in synchronism with the timing of driving for traveling. That is, the position adjusting device 50
By adjusting the position of the OM 42 to create a state in which the intensity of the first-order diffracted light becomes maximum, it is possible to create a state in which the intensity of the 0th-order light becomes minimum. As a result, the shutter mechanism 22 allows the hologram recording medium 3
When driving the hologram intermittently, the situation where the hologram recording medium 3 is exposed to zero-order light can be reliably avoided.

As described above in detail, the holographic stereogram producing apparatus 10 according to the embodiment of the present invention uses the AOM 42 for the shutter mechanism 22 to expose and record the elementary hologram on the hologram recording medium 3. In doing so, no vibration occurs. Thus, the holographic stereogram producing device 10
Even when a dry process film is used for the hologram recording medium 3, stable exposure recording can be performed to produce a high-resolution, high-quality holographic stereogram.

Further, by using the AOM 42 for the shutter mechanism 22, the holographic stereogram producing apparatus 10 does not need to have a vibration removing mechanism for removing the vibration, and the entire holographic stereogram producing apparatus does not become large-scale.

The shutter mechanism 22 does not open and close mechanically as in the prior art, but blocks and transmits the zero-order light used for exposure recording of the element hologram by periodically modulating the intensity. Longer lifespan,
It can withstand long-term continuous exposure. Therefore, the holographic stereogram producing apparatus 10 can perform long-term continuous exposure.

The holographic stereogram producing apparatus 10 can sequentially record and record elementary holograms at high speed by using the laser light source 21 composed of a high-power semiconductor-excited YAG laser device.

The AOM constituting the shutter mechanism 22
The holographic stereogram producing device 10 can freely adjust the so-called shutter speed because the 42 periodically modulates the intensity of the 0th-order light and the 1st-order diffracted light according to the control by the control signal C1. Thus, the holographic stereogram producing device 10
An optimum exposure time can be given to the hologram recording medium 3 to be exposed.

Further, the holographic stereogram producing apparatus 10 ensures that the laser beam L1 is incident when the production of the holographic stereogram is started by the mechanical shutter 40 constituting the shutter mechanism 22, and that the holographic stereogram is produced. When the production of the gram is completely completed, the laser beam L1 can be completely shut off.

It should be noted that the present invention is not limited to only the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

For example, a case has been described where a monochromatic holographic stereogram is produced using monochromatic light emitted from one laser light source 21. However, a color holographic stereogram is produced using a plurality of laser light sources. The present invention can also be applied to the case where In that case, the AO used for the shutter mechanism 22
For M42, an acousto-optic medium suitable for the wavelength of each incident light is selected.

In the above embodiment, the AOM 42 in which the piezoelectric element 45 is adhered to the acousto-optic medium 44 has been described as the shutter mechanism 22.
An acousto-optic deflector (hereinafter, Acoust Optic) is used instead of OM42.
Deflector: AOD) may be used.
The AOD has the same configuration and operation principle as the AOM 42, and performs intensity modulation of first-order diffracted light and zero-order light by frequency modulation of ultrasonic waves.

[0091]

As described above in detail, in the holographic stereogram producing apparatus according to the present invention, the acousto-optic means affects the characteristics of the laser light emitted from the laser light source by the acousto-optic effect, The laser light is cut off and transmitted by performing the intensity modulation, and the mechanical shutter means is positioned before or after the acousto-optic means to cut off and transmit the laser light by a mechanical opening and closing operation, and the recording means transmits. Splits the laser light, transmits the image information including the parallax information displayed by the image information display control means, and makes the object light, which is image-modulated, incident on one surface of the hologram recording medium. The reference light having coherence is incident on the other surface of the hologram recording medium or the surface on which the object light is incident, and the interference fringes generated by the object light and the reference light are applied to the element E. Sequentially exposed recorded on the hologram recording medium as grams.

Thus, the holographic stereogram producing apparatus does not generate vibration when sequentially exposing and recording the interference fringes generated by the object light and the reference light as the element hologram on the hologram recording medium. Therefore, the holographic stereogram producing apparatus can perform stable exposure recording and produce a high-quality holographic stereogram.

Further, the holographic stereogram producing apparatus does not need to be provided with a vibration removing mechanism for removing vibration, so that the whole is not large-scale.

Further, the holographic stereogram producing apparatus cuts and transmits the laser light by modulating the intensity of the laser light, so that long-term continuous exposure can be performed.

The shutter manufacturing apparatus according to the present invention comprises:
The acousto-optic means influences the characteristics of the laser light emitted from the laser light source by the acousto-optic effect, and modulates the intensity of the laser light to cut off and transmit the laser light. A holographic stereogram producing apparatus in which a laser beam is cut off and transmitted by a mechanical opening / closing operation at a front stage or a rear stage, and interference fringes generated by the transmitted laser beam are sequentially exposed and recorded on a hologram recording medium as element holograms. Used for

Accordingly, the shutter device does not generate vibration when the holographic stereogram producing device sequentially exposes and records the interference fringes generated by the object light and the reference light as the element hologram on the hologram recording medium.

Further, the shutter device blocks and transmits the laser light by modulating the intensity of the laser light, so that it can withstand long-term continuous exposure.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an overall configuration of a holographic stereogram producing apparatus shown as an embodiment of the present invention.

FIGS. 2A and 2B are diagrams illustrating an optical system of the holographic stereogram producing apparatus, wherein FIG. 2A is a front view of the optical system of the holographic stereogram producing apparatus, and FIG. It is a top view of the optical system of a graphic stereogram production apparatus.

FIG. 3 is a diagram illustrating a configuration of a shutter mechanism included in the holographic stereogram producing apparatus.

FIG. 4 shows an acousto-optic modulator (AO) used for a shutter mechanism constituting the holographic stereogram producing apparatus.
It is a figure explaining the operation principle of M).

FIG. 5 shows an acousto-optic modulator (AO) used for a shutter mechanism constituting the holographic stereogram producing apparatus.
It is a figure explaining the whole composition of the position adjustment device which adjusts the position of M).

6A and 6B are diagrams illustrating an optical system of a conventional holographic stereogram producing apparatus, wherein FIG. 6A is a front view of the optical system of the holographic stereogram producing apparatus, and FIG. FIG. 2 is a plan view of an optical system of the holographic stereogram producing device.

[Explanation of symbols]

10 Holographic stereogram producing device, 13
Holographic stereogram production unit, 21 laser light source, 22 shutter mechanism, 23 half mirror, 2
4, 33 mirror, 25, 31 spatial filter, 26, 32 collimator lens, 27 projection lens,
28 cylindrical lens, 29 mask, 30
Transmissive liquid crystal display, 35 recording medium feeding mechanism, 40 mechanical shutter, 41 drive voltage supply unit, 42 acousto-optic modulator (AOM), 43 light shielding unit, 44 acousto-optic medium, 4
Reference Signs List 5 piezoelectric element, 50 position adjustment device, 51 gonio stage, 51a, b operation section, 52 rotation stage, 53
Oscilloscope, 54 photo sensor, 55 pulse function generator, 56 DC power supply, 57
AOM driver

Claims (14)

[Claims] 1. A holographic stereogram producing apparatus for producing a holographic stereogram, comprising: a laser light source for emitting laser light; image information display control means for displaying a plurality of image information including parallax information; Shutter means for blocking and transmitting the laser light emitted from the light source; and an object modulated by splitting the laser light transmitted through the shutter means and transmitting each image information displayed by the image information display control means. The light is incident on one surface of the hologram recording medium, the reference light having coherence to the object light is incident on the other surface or the one surface of the hologram recording medium, and the object light and Recording means for sequentially exposing and recording the interference fringes generated by the reference light as an element hologram on the hologram recording medium. An acousto-optic means for influencing the characteristics of the laser light by means of an acousto-optic effect and blocking and transmitting the laser light by modulating the intensity of the laser light; A holographic stereogram producing apparatus, comprising: a mechanical shutter means located at a subsequent stage for blocking and transmitting the laser light by performing a mechanical opening / closing operation. 2. The acousto-optic means comprises: an acousto-optic medium;
An ultrasonic wave applying means for applying ultrasonic waves converted from an electric signal to the acousto-optic medium, wherein the acousto-optical modulator performs intensity modulation of the laser light in accordance with intensity modulation of the ultrasonic waves. 2. The holographic stereogram producing apparatus according to claim 1, wherein: 3. The acousto-optic means comprises: an acousto-optic medium;
An ultrasonic wave applying means for applying an ultrasonic wave converted from an electric signal to the acousto-optic medium, wherein the acousto-optical deflector performs intensity modulation of the laser light in accordance with frequency modulation of the ultrasonic wave. 2. The holographic stereogram producing apparatus according to claim 1, wherein: 4. The shutter means comprises a position adjusting means for adjusting a position of the acousto-optic means under a condition that the laser beam incident on the acousto-optic means is diffracted at a predetermined diffraction angle. Item 3. The holographic stereogram producing apparatus according to Item 1. 5. The apparatus according to claim 4, wherein said position adjusting means is a gonio stage on which said acousto-optic means is mounted and which changes an angle between an optical axis of said laser beam and said acousto-optic means. A holographic stereogram producing apparatus as described in the above. 6. The holographic stereogram producing apparatus according to claim 4, wherein said position adjusting means is a rotary stage on which said acousto-optic means is mounted and which moves circularly in forward and reverse directions. 7. The holographic stereogram producing apparatus according to claim 1, wherein said shutter means includes a light shielding means for shielding unnecessary diffracted light transmitted through said acousto-optic means from said recording means. . 8. A hologram recording medium, wherein a laser beam emitted from a laser light source is branched, and object light image-modulated by transmitting each image information of a plurality of pieces of image information including parallax information is formed on one side of a hologram recording medium. Incident on the surface, the reference light having coherence to the object light is incident on the other surface or the one surface of the hologram recording medium, interference fringes generated by the object light and the reference light A shutter device that is used in a holographic stereogram producing apparatus that sequentially exposes and records the hologram recording medium as an elementary hologram, and that blocks and transmits laser light emitted from the laser light source; Affect
Acousto-optic means for intercepting and transmitting the laser light by performing intensity modulation of the laser light, and being located at a stage before or after the acousto-optic means, and performing a mechanical opening / closing operation to shut off the laser light and And a mechanical shutter means for transmitting light. 9. The acousto-optic means comprises: an acousto-optic medium;
An ultrasonic wave applying means for applying ultrasonic waves converted from an electric signal to the acousto-optic medium, wherein the acousto-optical modulator performs intensity modulation of the laser light in accordance with intensity modulation of the ultrasonic waves. 9. The shutter device according to claim 8, wherein: 10. The acousto-optic means includes an acousto-optic medium, and an ultrasonic wave applying means for applying an ultrasonic wave converted from an electric signal to the acousto-optic medium, and according to frequency modulation of the ultrasonic wave. 9. The shutter device according to claim 8, wherein the shutter device is an acousto-optic deflector that performs intensity modulation of the laser light. 11. A shutter according to claim 8, further comprising a position adjusting means for adjusting a position of said acousto-optic means under a condition that said laser light incident on said acousto-optic means is diffracted at a predetermined diffraction angle. apparatus. 12. The apparatus according to claim 11, wherein said position adjusting means is a gonio stage on which said acousto-optic means is mounted and which changes an angle between an optical axis of said laser beam and said acousto-optic means. The shutter device according to any one of the preceding claims. 13. The shutter device according to claim 11, wherein said position adjusting means is a rotary stage on which said acousto-optic means is mounted and which moves circularly in forward and reverse directions. 14. The shutter device according to claim 8, further comprising a light shielding means for shielding unnecessary diffracted light transmitted through said acousto-optic means from said recording means.