JP2008209722A - Method for producing multiple-exposure hologram and multiple-exposure hologram - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a multiple-exposure hologram by which a hologram with a great impact can be easily obtained. <P>SOLUTION: The method comprises: producing a master hologram recording medium AM by actual imaging using one optical interference exposure means 10; producing a hologram recording medium DM by a digital process using the other optical interference exposure means 20; duplicating the first master hologram recording medium AM; replacing the master hologram recording medium DM in the other exposure means by the duplicated hologram recording medium AM to carry out multiple exposure. In the above embodiment, an image with high accuracy by actual imaging and, for example, a three-dimensional character can be recorded together in a single recording medium, and therefore a hologram with a great impact can be produced. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a multiple exposure hologram and a produced multiple exposure hologram, and more particularly to a method for producing a multiple exposure hologram in which a plurality of holograms are recorded on a recording medium.

Conventionally, it is known that another multiple exposure hologram recording is formed by partially overlapping on a surface having a hologram recording (see Patent Document 1).
In the multiple exposure hologram described in Patent Document 1, a positive photoresist is applied on the surface having a hologram record, a hologram pattern is newly exposed on the applied positive photoresist, and then a mask pattern is applied. Then, the photoresist rod is partially irradiated with ultraviolet rays and developed.

In addition to this, for example, a technique for forming a multiple exposure hologram by bonding a stereogram and a hologram is disclosed (see Patent Document 2).
In the multiple exposure hologram described in Patent Document 2, a holographic stereogram is produced by recording on a first recording medium, and a hologram from an actual object is separately produced on a second recording medium. The multiple exposure hologram is produced by laminating the first recording medium and the second recording medium.
JP 59-154482 A Japanese Patent Laid-Open No. 11-84994

  By the way, in recent years, attention has been paid using a hologram. For example, by installing it in a commercial facility where many people gather, it is going to be used as an event or information announcement or advertisement. Attempts have also been made to provide high-impact brand images and provide product guidance by installing holograms in stores. In addition, by installing in a reception or showroom, it is possible to express a company logo or product in 3D.

  However, in the multiple exposure hologram described in Patent Document 1 described above, since a real-image hologram obtained by directly photographing an entity is used, a high-resolution hologram can be obtained. However, multiple exposure reduces the diffraction efficiency per image. Further, it is difficult to obtain the brightness of the hologram itself, and further impact is required. The recording medium mainly composed of a photopolymer used in Patent Document 1 has a sensitivity that is one to two orders of magnitude lower than that of a recording medium containing a silver salt emulsion, and requires a long exposure when the exposure apparatus is the same. It becomes. Moreover, in this case, a stationary object such as an ornament is good, but a moving object such as a person or an animal cannot be a subject.

  In addition, in the multiple exposure hologram described in Patent Document 2 described above, a hologram by actual photography and a hologram produced through digital are used, but a multiple exposure hologram is produced by pasting both holograms. However, accurate positioning is difficult, time-consuming and cumbersome. Furthermore, since the recording surface of the created hologram is separated by the thickness of the medium, there is a problem that a subtle deviation occurs depending on the direction of observation, making it difficult to see.

Further, as a basic problem of holograms by actual shooting as described above, it takes several hours to create even a size of about A4, and if it is intended to make a clear and large one, it is necessary to make the irradiation light source a powerful laser. In addition, there is a problem that an optical system for creating a hologram becomes large and expensive.
In particular, in the case of a recording medium containing a silver salt emulsion, the average particle diameter is about 40 nm, and the diffraction efficiency is lower at a wavelength of B (blue) than at other wavelengths R (red) and G (green). The trend was remarkable. In this case, in order to achieve white balance, the exposure time for the B (blue) wavelength is increased by that amount, or the exposure amount for other wavelengths is limited. The effect becomes significant, and the hologram becomes dark. Therefore, there arises a problem that the irradiation light source must be a powerful laser.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a method for producing a multiple exposure hologram that can be obtained by placing a high-definition, bright and impactful hologram in a relatively small optical system. There is to do.

The present invention has been achieved by the following configuration for the above-described object.
(1) In a multiple exposure hologram manufacturing method in which a recording medium is exposed multiple times,
A master hologram recording medium is produced and developed by an analog optical interference type exposure means, and a duplicate recording medium is produced by the hologram duplication optical system using the produced master hologram recording medium, and produced by the hologram duplication optical system. A multi-exposure hologram manufacturing method, wherein a hologram by another type of light interference exposure means is subjected to multiple exposure formation on the duplicate recording medium before development processing.

  In the multi-exposure hologram manufacturing method configured as described above, a master hologram recording medium is manufactured by actual shooting as an analog optical interference exposure means, and a replica of the analog master hologram recording medium is manufactured using a hologram replication optical system. Thereafter, a hologram by multiple optical interference exposure means is formed by multiple exposure on a copy recording medium before development processing created by the hologram duplication optical system. By doing so, multiple exposure can be performed in a duplicate optical system with the same optical axis that is accurate as a position reference, and formation is performed on the same plane, and image misalignment does not occur. In this case, it is possible to record a high-accuracy hologram by actual shooting and, for example, a 3D character produced through digital, while accurately aligning it on a single recording medium, producing an impact poster or the like. can do.

  Furthermore, in the multiple exposure hologram manufacturing method configured as described above, since one master hologram recording medium records an analog hologram, it is possible to reproduce a high-accuracy image by actual shooting. Here, the analog hologram means a real hologram produced by directly photographing an object.

(2) After exchanging the analog master hologram recording medium, which has been replicated in the hologram replicating optical system, with a master hologram recording medium produced and developed by another type of optical interference exposure means, The method for producing a multiple exposure hologram according to the above (1), wherein the duplicate recording medium is subjected to multiple exposure to produce one multiple exposure hologram.

  In the multi-exposure hologram manufacturing method configured as described above, a master hologram is also manufactured by another type of optical interference exposure means, and the hologram replication optical system can perform multiple exposure only by exchanging the master hologram. The hologram can be subjected to replication after storage, and a multiple exposure hologram can be produced when necessary.

(3) The duplication recording medium before development processing created by the hologram duplication optical system is moved to another type of optical interference exposure optical system, and the duplicate duplication recording medium after movement is moved to another type of optical interference exposure means. The method of producing a multiple exposure hologram according to the above (1), wherein a multiple exposure hologram is produced by multiple exposure.

  In the multi-exposure hologram manufacturing method configured as described above, an analog duplication recording medium is directly introduced into a hologram manufacturing optical system of another method to manufacture a multi-exposure hologram. It can be omitted and the process can be simplified.

(4) Any of the above (1) to (3), wherein the master hologram recording medium of the optical interference exposure means according to another method is produced on the recording medium by using direct or indirect optical interference with a planar image 2. A method for producing a multiple exposure hologram according to item 1.

In the multi-exposure hologram manufacturing method configured as described above, the hologram manufactured on the recording medium by using the direct or indirect optical interference with the planar image is relatively easy in the position of the image and the observation direction. Because it is set, it is easy to work with an analog hologram that records a three-dimensional object and has a large amount of information but does not change the position and observation angle setting, and easily limits the range of actual multiple exposure The entire image can be kept bright as an arrangement that reduces the multiple range in which the diffraction efficiency decreases.
By superimposing a planar image of characters, etc. on these, it is possible to reproduce a poster that has been shown with a mixture of photographs and characters in a conventional manner in a three-dimensional manner, and to produce an impact hologram. be able to.

(5) The front-rear positional relationship between the holograms created in the duplicate recording medium can be changed according to the distance setting between the duplicate recording medium and the master hologram recording medium in the hologram duplication optical system. The method for producing a multiple exposure hologram according to any one of the above (4).

  In the multiple exposure hologram manufacturing method configured as described above, for example, the positional relationship between an image and another image when reproduced, and the positional relationship between an image and characters are easily set. Can do.

(6) The method for producing a multiple exposure hologram according to any one of (1) to (5) above, wherein the recording medium comprises a photosensitive layer containing a silver salt emulsion having a main particle size of 18 to 28 nm.

  In the multi-exposure hologram manufacturing method configured as described above, since a recording medium containing a silver salt emulsion with small grains is used, the number of grains per pitch of interference fringes increases, and not only the overall diffraction efficiency is improved, Even if the reaction of each particle is small, the number of particles increases, so that the resolution is improved and a bright hologram can be obtained.

(7) The multiple exposure hologram manufacturing method according to any one of (1) to (6), wherein the exposure amount ratio among R, G, and B is substantially the same for the white balance of the recording medium.

  In the multi-exposure hologram manufacturing method configured as described above, there is no decrease in the diffraction efficiency of the B (blue) wavelength in the photosensitive layer containing a silver salt emulsion having a main grain size of 18 to 28 nm, and R (red) G in terms of white balance. By making the exposure amount ratio between (green) and B (blue) substantially the same, the diffraction efficiency of the recording medium can be fully utilized if the exposure time is the same as before, and the hologram is brightened, or The exposure can be performed in a short time.

(8) A hologram produced by the multiple exposure hologram production method according to any one of (1) to (7) above, wherein light interference by a plurality of types of optical interference type exposure means including an analog type is caused. A multiple exposure hologram recorded on one recording medium.

  In the hologram configured as described above, an image and an image can be reproduced at the same time or an image and a character can be reproduced at the same time by using a single recording medium, thereby providing an impact image.

  According to the present invention, in a relatively small optical system, an image and an image can be simultaneously recorded on a single recording medium by multiple exposure, and an image and a character can be simultaneously recorded. Can be provided easily.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a flowchart showing an embodiment of a multiple exposure hologram manufacturing method according to the first embodiment of the present invention, FIG. 2 is a block diagram showing an analog exposure optical system, and FIGS. 4 is a block diagram showing a digital exposure optical system, and FIG. 4 is a block diagram showing a replication optical system.

  In the multiple exposure hologram manufacturing method of this embodiment, the multiple exposure hologram 1 is manufactured by multiple exposures. Here, as an example, as shown in FIG. 1, a live-action hologram (hereinafter referred to as “analog hologram AH”) produced by directly photographing an object as a master hologram recording medium by one of the light interference type exposure means. As a master hologram recording medium by other optical interference type exposure means, a hologram for artificially producing three-dimensional information through digital processing or the like (this embodiment is a multiplex hologram, hereinafter referred to as “digital hologram DH”). ), And multiple exposure hologram 1 is manufactured by multiple exposure of these master holograms using a replication optical system. It is assumed that the analog hologram AH and the digital hologram DH are in color.

In the multiple exposure hologram manufacturing method of the present embodiment shown in FIG. 1, a master for analog hologram (analog master AM) (step S1) as a master hologram recording medium and a digital hologram are used by a plurality of types of optical interference exposure means. A master (digital master DM) (step S2) is prepared.
First, production of the analog master AM (step S1) will be described. Exposure is performed using the analog exposure optical system 10 shown in FIG. 2 (step S11), and red, green, and blue analog masters AM are produced. The analog exposure optical system 10 includes R (red) laser L1, G (green) laser L2, and B (blue) laser L3 as laser light sources L.

  The laser light source L preferably has a single wavelength oscillation (single mode), high coherence (coherence), and a spectral line width of less than 10 MHz. Furthermore, a hologram having a coherent length of about 200 mm or more is used for hologram imaging, although it depends on the hologram size and the object size. Preferably, one of 1 m or more is selected. In addition, since interference fringes with a submicron order pitch are formed on the recording medium, it is necessary to suppress vibration (movement within a predetermined time) of the interference fringe pitch order during exposure in the optical system. That is, as the exposure time is as short as possible, the influence of vibration is small, so that the laser power is preferably large. For example, a laser light source of about 10 to 400 mW is desirable.

  In front of the laser light source L, shutters S1, S2, and S3 are provided, respectively. Since a laser beam with high coherence is required, the laser light source L is normally turned on in advance before the start of use to maintain the laser oscillation state and stabilize the temperature and oscillation state in the laser. During this time, if laser light enters the optical system, unnecessary exposure occurs, so shutters S1, S2, and S3 are provided. Further, when exposing to the recording medium 11 for holography, the recording medium 11 can be controlled to give a desired energy by exposing for a predetermined time.

  In front of each of the shutters S1, S2, and S3, light attenuation filters ND1, ND2, and ND3 are provided to adjust the amount of light. As the light attenuation filter, an absorption type or reflection type fixed attenuation filter or a rotary variable attenuation filter can be used. Therefore, at the time of adjusting the exposure energy for the recording medium 11, not only the time adjustment by the shutters S1, S2, and S3 but also the exposure adjustment by the light attenuation filters ND1, ND2, and ND3 are possible.

  In front of each light attenuating filter ND1, ND2, ND3, λ / 2 wavelength plates W1, W2, W3 suitable for each wavelength are provided, and the polarization angle of incident light can be rotated. Yes. That is, since the polarization beam splitter PBS provided in front of each optical attenuation filter ND1, ND2, ND3 has a ratio in which it is divided into straight light and reflected light depending on the polarization angle state of incident light, λ / By rotating the two-wavelength plates W1, W2, and W3 in a direction perpendicular to the optical axis direction, the polarization angle of the transmitted light from the λ / 2-wavelength plates W1, W2, and W3 is changed, and the light beams from the subsequent polarizing beam splitter PBS are changed. The ratio of transmitted light and reflected light can be changed.

  Polarizing beam splitters PBS1, PBS2, and PBS3 are respectively provided in front of the λ / 2 wave plates W1, W2, and W3. The object light Ba that irradiates the object M with the light from the laser light source L, and the analog master. The reference beam Bb is irradiated with AH. The polarization beam splitters PBS1, PBS2, and PBS3 are preferably used in accordance with each wavelength, and a cube type or a flat plate type can be used as appropriate. It is desirable to use a type. When the analog master AH is exposed, the ratio Ba: Bb between the object light Ba and the reference light Bb is changed from 1: 1 to 10: 1 depending on the color and gloss of the photographed object M. At this time, the above-mentioned λ / 2 wavelength plates W1, W2, and W3 are rotated to change the spectral ratio after transmission or reflection of the polarizing beam splitter PBS.

  A first stage dichroic mirror DM1 is provided downstream of the polarization beam splitter PBS1 on the object beam Ba side, and a second stage dichroic mirror DM2 is provided downstream thereof. Further, a first stage dichroic mirror DM3 is provided downstream of the polarization beam splitter PBS1 on the reference light Bb side, and a second stage dichroic mirror DM4 is provided downstream thereof.

  Further, a mirror M1 is provided downstream of the polarization beam splitter PBS2 on the object beam Ba side so that transmitted light enters the first stage dichroic mirror DM1. Similarly, a mirror M2 is provided downstream of the polarization beam splitter PBS3 on the object beam Ba side so that transmitted light enters the second stage dichroic mirror DM2. On the other hand, a mirror M3 is provided downstream of the polarization beam splitter PBS2 on the side of the reference light Bb so that the reflected light enters the first stage dichroic mirror DM3. Similarly, a mirror M4 is provided downstream of the polarization beam splitter PBS3 on the side of the reference light Bb, and reflected light is incident on the second stage dichroic mirror DM4.

  The first-stage dichroic mirrors DM1 and DM3 transmit red, reflect green toward the downstream side, and place red and green on the same optical axis. The second stage dichroic mirrors DM2 and DM4 transmit red / green, reflect blue, and place red / green and blue on the same optical axis. As a dichroic mirror, a cube type or a flat plate type can be used as appropriate. However, since the flat plate type causes an optical axis difference, it is desirable to use a cube type.

  When recording on the recording medium 11 one by one as the red, green, and blue analog master AM, the laser light source L described above is sequentially switched to the red laser L1, the green laser L2, and the blue laser L3, or the shutter. By controlling S1 to S3 and sequentially replacing the recording medium 11 with a new one, analog masters AM1 to AM3 of each color can be produced one by one. Alternatively, a single laser light source may be provided as the laser light source L, and a single color optical system that does not include the polarization beam splitters PBS2 and PBS3 and the dichroic mirrors DM1 to DM4 and the mirrors M1 to M4 may be used. In this case, the analog light sources AM1 to AM3 of the respective colors can be produced by sequentially replacing the laser light source L from red to green to blue and replacing the recording medium 11 with a new one.

  It is desirable that the optical axis center distances of the light Ba and Bb light from the Ba / Bb light after being split by the polarization beam splitter PBS to the analog master AM should be substantially equal, and the difference is more than the coherent length of the laser light source L used. It is necessary to make it smaller. For this reason, when the distance between the light Ba and the light beam Bb cannot be matched due to the arrangement of the optical component, the photographed object, and the recording medium 11 for holography, the light path adjustment mechanism (not shown) is used for adjustment. Specifically, the optical path length of either light Ba or Bb light from each polarization beam splitter PBS is adjusted so that the center optical path length from each polarization beam splitter PBS to the target hologram is ± 10 mm or less. To do.

  The light Ba1 from the dichroic mirrors DM1 and DM2 changes its direction by the mirror M11, and converts the parallel light incident by the lens L11 into divergent light Ba2. As the lens L11, for example, a microscope objective lens, in particular, a lens with a magnification of 20 to 50 times can be used as appropriate. Thereby, the light Ba1 is once condensed at the focal position of the lens L11 and then diverges. If necessary, the pinhole P11 is installed at the focal position, and the spatial filter SF1 is configured together with the lens L11, thereby removing the wavefront noise and distortion of the light Ba2 and creating a clear wavefront (spherical wave). Can do. Further, it is desirable to shield the diverging light Ba2 from here with a wall (not shown) or the like so that the analog master AM is not irradiated. The diverging light Ba2 is applied to the object M, and the object light Ba3 is applied to the recording medium 11.

  On the other hand, the light Bb1 from the dichroic mirrors DM3 and DM4 is converted into diverging light Bb2 to the concave mirror M15 by the lens L14 via the mirrors M12, M13, and M14. As the lens L14, the same lens L11 as described above can be used. Similarly to the light Ba, it is desirable that the pinhole P14 is installed at the focal position as necessary, and the spatial filter SF2 is configured together with the lens L14.

  At the time of analog master imaging, the concave mirror M15 converts the divergent light Bb2 from the lens L14 into a wide parallel light Bb3 and enters the analog master AM at 45 degrees with respect to the hologram normal as reference light Bb3. As a result, the analog master AM becomes a transmission hologram, and at the time of producing a duplicate hologram, which will be described later, it is possible to produce a hologram showing a three-dimensional object without distortion. In order to make the reference light Bb3 reflected by the concave mirror M15 as parallel light as possible, it is desirable that the divergent light Bb2 is incident on the concave mirror M15 at an acute angle to the extent that the optical path is not obstructed. In order to form parallel light, in addition to the concave mirror M15, an off-axis parabolic mirror can be used as long as it is a reflection system. In addition, a lens having a positive power can be used in the case of a transmission system, but since the focal position differs depending on the color (wavelength), it is necessary to slightly adjust the focal position depending on the laser wavelength used. If the parallel light can be produced firmly, the size and position of the image to be reproduced can be reproduced with good reproducibility even if the installation position of the analog master AM is slightly deviated during the production of a duplicate hologram later. It is most desirable to use an off-axis parabolic mirror that is highly accurate and does not require adjustment for each color.

  The analog master AM is usually manufactured with the film surface Ma on the object M side. When the film type recording medium 11 is used, it is preferably directly fixed to the holder, and a holder of the type that fixes all sides of the film is preferable. And the support body surface of a film is made into the glass side, it is made to adhere to a glass plate, and it fixes to a holder with the glass plate. The film has a thickness of 0.07 to 0.5 mm, and usually 0.2 mm is used. On the other hand, when a glass type (dry plate) recording medium 10 is used, it is desirable to fix it directly to the holder. The glass has a thickness of 1 to 5 mm, and usually 2 to 3 mm is used.

  When producing the analog masters AM1 to AM3 for three colors, the smaller the positional deviation, the lower the color deviation of the final hologram and the higher the quality. Further, when replicating hologram FH from three color (three) analog masters AM1 to AM3 at the time of producing a replica hologram, which will be described later, the smaller the positional deviation of each analog master AM1 to AM3, the smaller the color shift of the final hologram. There is little and becomes high quality. For this reason, the position accuracy of the holder and the installation position accuracy on the holder are desirably about ± 0.2 mm or less. Further, it is desirable to provide an adjustment mechanism that can move the analog master AM forward and backward in the optical axis direction by ± 50 mm or more.

  As shown in FIG. 1, the analog masters AM1 to AM3 produced by the analog exposure optical system 10 are developed (step S12).

Next, a master hologram (digital master DM) is produced by the holographic stereogram exposure optical system 20 shown in FIG. 3 (step S2).
In the holographic stereogram, first, as shown in FIG. 3A, an original image is created with a positive film (not digital) (step S21). For example, the original film 24 is produced by placing the object 22 on the turntable 21 and rotating it, photographing it with the camera 23, and recording images with slightly different horizontal parallax. Next, as shown in FIG. 3B, each of the original film 24 is irradiated with laser light 25, and an image formed by the spherical lens 26a and the cylindrical lens 26b is placed in front of the film 27 as a recording medium. It is recorded on the film 27 together with the reference light 29 through the slit 28 (step S22) and developed (step S23). In addition, when creating the digital master DM in color, a total of three are produced, one each for red, green, and blue.

In addition to the holographic stereogram 20, when producing the digital master DM, a spatial modulation element such as an LCD is used without using a positive film such as the original picture film 24, and it does not actually exist by computer graphics. A three-dimensional image can also be obtained. The resolution is equal to the exposure pitch (slit pitch), and if the exposure pitch is fine, a high-resolution hologram can be reproduced.
That is, the stereogram has a much smaller amount of information than the analog hologram AH and is accurately a pseudo-stereoscopic image. However, in addition to a photographed object by the camera 24 as an image source, the stereogram can be drawn by CG. A certain image can be obtained.

Next, a duplicate hologram FH is produced using the analog masters AM1 to AM3 produced previously (step S3).
FIG. 4 shows a duplicate optical system 30 used for producing the duplicate hologram FH. The same parts as those in the analog exposure optical system 10 described above with reference to FIG. The explanation will be diverted.

  As shown in FIG. 4, in the replication optical system 30, developed analog masters AM <b> 1 to AM <b> 3 are arranged one by one at the position of the symmetrical object M in the analog exposure optical system 10, and the analog master in the analog exposure optical system 10. A recording medium 31 for the duplicate hologram FH is arranged at the position of AM. Further, the mirror M11 and the spatial filter SF1 of the analog exposure optical system 10 are removed, and a lens L15, a pinhole P15, and a concave mirror M16 are provided. Then, the object light Ba1 in the analog exposure optical system 10 is converted into divergent light Ba4 by the lens L15 and the pinhole P15, reflected by the concave mirror M16, and irradiated to the duplicate hologram FH as the reference light Ba5. Here, since the influence of the image quality upon reproduction of the duplicate hologram FH is small depending on the type of the light beam, the divergent light Ba4 may be irradiated as it is, or may be converted into parallel light and irradiated, or the convergent light Ba5. It may be converted to irradiate. Therefore, it is possible to directly irradiate the duplicate hologram FH as the reference light from the lens L15 or the pinhole P15 without providing the concave mirror M16, but the convergent light Ba5 is most desirable.

  On the other hand, the reference light Bb3 in the analog exposure optical system 10 is irradiated to the analog master AM as the reproduction illumination light Bb4, and the light reproduced in the analog master AM is irradiated to the duplicate hologram FH as the object light Bb5. As a result, the analog master AM can be reproduced on the recording medium 31 and recorded on the recording medium 31 to form a duplicate hologram FH. When there are a plurality of analog masters AM as in the case of color, the analog masters AM are replaced one after another, and the exposure is performed by superimposing on one copy hologram FH without development.

Next, a holographic stereogram master (digital master DM) is placed at the position of the analog master AM in the replication optical system 30 and is exposed by being superimposed on the replication hologram FH created earlier (step S4). At this time, by adjusting the distance between the analog master AM and the digital master DM with respect to the recording medium 31, the distance between the image by the analog hologram AH and the image by the digital hologram DH at the time of reproduction can be arbitrarily set. .
In particular, when a spatial modulation element such as an LCD is used and a digital master DM is created by computer graphics, the position of the image and the direction of observation can be set relatively easily. It is easy to coordinate the position, etc., the range of multiple exposure with the image of the analog master AM can be easily limited, and the entire image can be kept bright as an arrangement that reduces the multiple range where the diffraction efficiency decreases. .

  Finally, the recording medium 31 is developed (step S5), and the multiple exposure hologram 1 is completed. Note that, reproduction of duplicate holograms is performed using white light that is relatively close to a point light source. In this case, a white lamp such as a halogen lamp or a metal halide lamp is usually used. At the time of reproduction, the hologram image with the least distortion can be reproduced by using the reference light in the reverse direction of the reproduction light from the white lamp to the duplicate hologram.

Next, a second embodiment will be described.
FIG. 5 is a flowchart showing an embodiment according to the multiple exposure hologram manufacturing method of the second embodiment, and FIG. 6 is a block diagram showing a digital exposure optical system.
The multi-exposure hologram manufacturing method of the present embodiment is first a real-time hologram (hereinafter referred to as “analog hologram AH”) by an optical interference type exposure means for directly irradiating and recording light on an object, as in step S1 of FIG. A master hologram recording medium is produced (step S6), and then the analog hologram AH is transferred to a duplication optical system to duplicate exposure to produce a duplicate hologram (step S7), and before the duplicate hologram is developed. Moving to another type of light interference type exposure means (exposure by a spatial light modulator in this embodiment) (thus becoming a dark room), the digital hologram DH is subjected to multiple exposure (step S8) and developed (step S8). Step S9) The multiple exposure hologram 1 is produced. It is assumed that the analog hologram AH and the digital hologram DH are in color.

  In the multiple exposure hologram manufacturing method of the second embodiment shown in FIG. 5, the analog hologram master (analog master AM) (step S6) is manufactured in step S1, and the analog hologram master replication (step S7) is performed in step S7. Since this is the same as S3 and the same optical system is used, the description relating to exposure uses FIGS. 2 and 4. FIG.

FIG. 6 shows a digital exposure optical system 40 used in another system (spatial light modulation element), but the same reference numerals are given to parts common to the analog exposure optical system 10 described above in FIG. Thus, duplicate explanations will be used.
When the copy exposure of the analog hologram AH is completed in step S7, the undeveloped copy hologram FH produced in step S7 is held at the exposure position at the exposure position of the digital exposure optical system 40 shown in FIG.

  In the digital exposure optical system 40, a beam diameter expanding means (beam expander) BE for expanding the beam diameter is provided at a position in the light traveling direction of the dichroic mirror DM2 of the object light Ba1. The beam expander BE includes a first lens L110, a pinhole P110, and a second lens L111. Usually, the diameter of the laser beam emitted from the laser light source is about 0.1 to 5 mm. The beam expander BE expands the beam diameter so that this is irradiated to the entire area of the later spatial light modulator SLM10.

  The pinhole P110 is not used for a normal beam expander BE, but in this embodiment, it is preferable to keep the beam quality high in order to use it for later optical interference. For this purpose, a circular pinhole of φ20 to 50 μm is installed at the focal position of the first lens L110.

  A second lens L111 is provided at the position of the pinhole P10 in the light traveling direction. The second lens L111 is a collimator lens having a focal length f that converts divergent light into parallel light. A lens having positive power is also used as the second lens L111. Further, it is preferable to use a lens such as an achromatic lens that has a small focal position change (small chromatic aberration) even when the wavelength is different.

  A transmissive spatial light modulation element SLM10 for placing image information as a hologram on the spread object light is provided at a position in the light traveling direction of the beam expander BE. This spatial light modulation element SLM10 is, for example, an electrical address type spatial light modulator, which is composed of a liquid crystal display or the like, and modulates the light intensity (amplitude) of the incident plane wave, which is the spread object light, for each pixel. Then, the image information is carried and transmitted. The display image of the spatial light modulation element SLM10, that is, the output light image from the spatial light modulation element SLM10 can be changed by changing the transmittance of each pixel. Thereby, image processing is performed according to the exposure position on the recording surface of the duplicate hologram FH.

  According to the transmissive spatial light modulation element SLM10 described above, a plurality of interspersed object light groups in which transmitted object light is divided at regular intervals by an unillustrated interlace exposure unit is used as a duplicate hologram FH recording surface. Multiple exposure holograms by moving the relative positions at the same time, performing high-speed exposure with a large number of dots, and causing interference with reference light, which will be described later, on an undeveloped duplicate hologram FH arranged at the exposure position Create (Step S8)

The reference light optical system will be described below.
A reference light mirror M20 is provided at the position of the dichroic mirror DM4 for the reference light Bb1 in the light traveling direction. Further, the reference light mirror M20 is configured as a reference light beam expander by sequentially arranging a lens L120, a pinhole P120, and a lens L121 at the light traveling direction position.

  The lens L120 corresponds to the first object light lens L110, the aperture (pinhole) P120 corresponds to the object light aperture (pinhole P110), the lens L121 corresponds to the second object light lens L111, and the object It has the same effect as the beam expander BE for light.

  A reference light final mirror M21 is disposed at the position of the lens L121 in the light traveling direction. The reference light final mirror M21 is a mirror that deflects (directs) the reference light toward the recording medium at a predetermined angle. The size of the reference light Bb1 reflected by the reference light final mirror M21 is irradiated with uniform illuminance over the entire area of the object light exposure area of the duplicate hologram FH.

  As described above, due to the interference between the reference light and the object light by the transmissive spatial light modulator SLM10, the digital hologram DH is subjected to multiple exposure on the undeveloped duplicate hologram (step S8) and developed. (Step S9) A multiple exposure hologram FH is produced.

  FIGS. 7 and 8 show examples of hologram (hybrid hologram) posters 1 and 1a created by superposing an analog hologram AH and a digital hologram DH according to this embodiment. FIG. 7 shows a poster 1 in which “3D characters” that are digital holograms and “bag” that is an analog hologram AH overlap, and FIG. 8 shows a poster 1a in which both holograms do not overlap. That is, when duplicating, if the distance L (see FIG. 4) between the digital master DM and the duplicate hologram FH is set short, the character that is the reproduced image of the digital master DM is placed behind the bag that is the reproduced image of the analog master AM. It will be arranged and recorded, and as shown in FIG. On the other hand, if the distance L between the digital master DM and the duplicate hologram FH is set to be long, the characters that are the reproduction image of the digital master DM are arranged and recorded in front of the bag that is the reproduction image of the analog master AM. It becomes the image that the character is raised forward.

  According to the multiple exposure hologram creating method described above, an analog master AM is produced by actual shooting using the analog exposure optical system 10, and a digital master DM is produced by the holographic stereogram exposure optical system 20. Replicate for AM. Then, by replacing the copied analog master AM with the digital master DM and performing multiple exposure, it is possible to record a high-accuracy image by actual shooting and, for example, 3D characters on one recording medium. A hologram can be produced.

  As the recording medium 11 for recording the analog hologram AH, a silver salt photosensitive material is generally used. In the present embodiment, a recording medium having the following photosensitive layer is used.

(Preparation of emulsion)
2000 mL of ion-exchanged water containing 9.0 g of deionized bone gelatin having a KBr of 0.70 g and an average molecular weight of 100,000 was kept at 15 ° C. and stirred vigorously. After adding 0.17 g of thiourea dioxide, the pH was adjusted to 6.0 with an aqueous sodium hydroxide solution. 500 ml of an aqueous solution of AgNO ₃ (32.0 g) and an aqueous KBr solution containing 2.0 g of deionized bone gelatin having an average molecular weight of 20000 and 1 mol% of KI were added over 5 minutes by the double jet method. At this time, the silver potential was kept at −20 mV with respect to the saturated calomel electrode. Three minutes after the start of addition of the aqueous AgNO ₃ solution during grain formation, 1 × 10 ⁻³ mol of an aqueous K ₂ [IrCl ₆ ] solution was added to 1 mol of silver halide. Four minutes after the start of addition of the aqueous AgNO ₃ solution during grain formation, 1 × 10 ⁻³ mol of an aqueous K ₄ [Fe (CN) ₆ ] solution was added to 1 mol of silver halide. At the end of the addition of the aqueous AgNO ₃ solution, 1.0 × 10 ⁻³ mol of supersensitizer SS-1 is added to 1 mol of silver halide, and then sensitizing dyes S-1 and S-2 are added to 45: In a molar ratio of 55, 3.0 × 10 ⁻³ mol was added to 1 mol of silver halide. The sensitizing dye was used as a solid dispersion prepared by the method described in JP-A-11-52507. Dissolve 7 g of sodium nitrate and 3 g of sodium sulfate in 80 g of ion-exchanged water, add 10 g of sensitizing dye, and disperse for 50 minutes at 2000 rpm using a dissolver blade under the condition of 60 ° C. I got a thing.
After raising the temperature to 20 ° C., ordinary washing with water was performed. After adding ion exchange water at 25 ° C. containing 14 g of deionized bone gelatin having an average molecular weight of 20,000, PH was adjusted to 6.0 at 30 ° C. The temperature was raised to 35 ° C. and thiourea dioxide (6.0 × 10 ⁻⁵ mol), chloroauric acid (9.0 × 10 ⁻⁴ mol), sodium thiosulfate (1 mol) per 1 mol of silver halide. 0.0 × 10 ⁻³ mol) and N, N-dimethylselenourea (9.0 × 10 ⁻⁴ mol) were added for optimal chemical sensitization. Chemical sensitization was completed by adding Cpd-1 (1.0 × 10 ⁻³ mol) and Cpd-2 (5.0 × 10 ⁻³ mol) to 1 mol of silver halide as an antifoggant. .
The emulsion grains of this emulsion were cubic grains having a particle diameter of approximately 18 nm to 28 nm, a number average equivalent circle diameter of 15 nm, and a variation coefficient of equivalent circle diameter of 15%. The emulsion grains of this emulsion were silver bromide grains containing 3 mol% of silver iodide.

The above emulsion was coated on a cellulose triacetate film support having a thickness of 200 μm provided with an undercoat layer. Application conditions are shown below. The number represents the coating amount (g / m ² ), and the silver halide emulsion represents the coating amount in terms of silver.

(Emulsion layer)
The following compounds were added to the emulsion and coated such that the silver coating amount was 6.75 g / m ² .
Emulsion 6.75
Gelatin 10.25
Cpd-4 0.10
Cpd-5 0.50
Cpd-6 0.07

  In addition to these, the following compounds Cpd-7 to Cpd-11 and Cpd-13 were added to coat the emulsion layer.

A back layer was coated on the surface opposite to the surface coated with the emulsion layer. Application conditions are shown below. The numbers represent the coating amount (g / m ² ).

(Back layer)
<Preparation and application of back layer coating solution>
The following compound was added to the gelatin aqueous solution and coated so that the gelatin coating amount was 10.50 g / m ² .
Gelatin (Ca ²⁺ content 30 ppm) 10.50
Polymethylmethacrylate fine particles (average particle size 4.3 μm) 0.015
Sodium p-dodecylbenzenesulfonate 0.025
Dihexyl-α-sulfosuccinate sodium 0.11
N-perfluorooctanesulfonyl-N-propylglycine potassium 0.025
Sodium sulfate 0.04
Sodium acetate 0.04
Potassium nitrate 0.12
Cpd-5 0.50
Cpd-6 0.05
Cpd-12 0.02

  The thus prepared coated sample had a dry film thickness of 12.0 μm on the emulsion layer side and a dry film thickness of 9.0 μm on the back layer side.

  Thereby, since the recording medium 11 containing a silver salt emulsion having small grains is used, the number of grains per pitch of interference fringes is increased, and not only the overall diffraction efficiency is improved, but also the number of grains can be reduced even if the individual reaction of the grains is small. By increasing the resolution, the resolution is improved and a bright hologram can be obtained.

  Further, as described above, in the photosensitive layer containing a silver salt emulsion having a main particle size of 18 to 28 nm, there is no decrease in diffraction efficiency at the B (blue) wavelength even when compared with the R (red) G (green) wavelength. Therefore, regarding the white balance, the exposure ratio between R (red), G (green), and B (blue) is made substantially the same, so that the diffraction efficiency of the recording medium is fully utilized if the exposure time is the same as the conventional exposure time. The hologram can be brightened. On the other hand, when the brightness is the same, the exposure can be completed in a short time.

Here, the multiple exposure hologram manufacturing method of the present invention is not limited to the above-described embodiment, and appropriate modifications and improvements can be made.
For example, in the above-described embodiment, the case where the analog exposure optical system 10 and the digital exposure optical system 20 are used as different optical interference exposure means and the analog hologram and the digital hologram are overlapped has been described. It is also possible to superimpose analog holograms obtained by the light interference type exposure means. For example, as an analog hologram, a rainbow hologram, an image hologram, a Denniske hologram, etc. can be used in addition to the above-mentioned ones.
Alternatively, it is possible to superimpose digital holograms. For example, a holographic stereogram is used as a digital hologram, but CG or the like can also be used.

In the above-described embodiment, the description has been given of the case where the reference light and the object light are irradiated on the recording medium from the same side when the analog master AM is manufactured. However, the object light and the reference light are applied to the recording medium. Then, irradiation (Lippmann hologram) may be performed from the opposite side. Similarly, the replication optical system 30 is used that irradiates the object light and the reference light from the opposite side to the recording medium (Lippmann hologram), but the reference light and the object light are irradiated from the same side to the recording medium. It is also possible to do.
In the above-described embodiment, the analog hologram and the digital hologram are colored, but may be a single color.
In the above-described embodiment, a replica of an analog hologram is produced first, and a digital hologram is subjected to multiple exposure on this duplicate. However, a digital hologram is produced first, and an analog hologram is multiplexed on this duplicate. You may make it expose.

  As described above, the multiple exposure hologram manufacturing method according to the present invention has an impact because multiple images can simultaneously record images and images on a single recording medium by multiple exposure, and images and characters can be recorded simultaneously. This has the effect that an image can be easily reproduced, and is useful as a method for producing a multiple exposure hologram in which a hologram is recorded on a single recording medium by a plurality of different light interference exposure means.

It is a flowchart which shows embodiment which concerns on the multiple exposure hologram production method of this invention. It is a block diagram which shows the exposure optical system for analogs. (A) And (B) is a block diagram which shows the exposure optical system for digital. It is a block diagram which shows a replication optical system. It is a flowchart which shows embodiment which concerns on the multiple exposure hologram production method of the 2nd Embodiment of this invention. It is a block diagram which shows the exposure optical system for digital. It is explanatory drawing which shows the case where it is the image produced by the multiple exposure hologram production method of this invention, and the analog hologram and the digital hologram overlap. It is explanatory drawing which shows the case where it is the image produced by the multiple exposure hologram production method of this invention, and the analog hologram and the digital hologram do not overlap.

Explanation of symbols

1 Multiple exposure hologram (hologram)
10 Analog exposure optical system (light interference exposure means)
11 Recording medium 20 Exposure optical system for holographic stereogram (light interference type exposure means)
30 Hologram replication optical system AH Analog hologram AM Analog master (master hologram recording medium)
DM Digital master (master hologram recording medium)
FH duplication hologram (duplication recording medium)

Claims (8)

In a multiple exposure hologram manufacturing method in which a recording medium is exposed multiple times,
A master hologram recording medium is produced and developed by an analog optical interference exposure means,
Using the master hologram recording medium thus created, a duplicate recording medium is produced with a hologram duplication optical system,
A method for producing a multiple exposure hologram, comprising: forming a hologram by multiple exposure using an optical interference type exposure means of another type on the duplication recording medium produced by the hologram duplication optical system before the development process.   The analog master hologram recording medium that has been replicated in the hologram replication optical system is replaced with a master hologram recording medium that has been prepared and developed by another type of light interference exposure means, and then the replication is performed in the hologram replication optical system. The method for producing a multiple exposure hologram according to claim 1, wherein a multiple exposure hologram is produced by performing multiple exposure on a recording medium.   The duplication recording medium before development processing created by the hologram duplication optical system is moved to another type of optical interference exposure optical system, and the duplicated recording medium after the movement is subjected to multiple exposure by another type of optical interference type exposure means. The method for producing a multiple exposure hologram according to claim 1, wherein one multiple exposure hologram is produced.   The multiplex according to any one of claims 1 to 3, wherein a master hologram recording medium of the optical interference type exposure means according to another method is produced on a recording medium by using direct or indirect optical interference with a planar image. Exposure hologram production method.   5. The front-rear positional relationship of each hologram produced in the duplicate recording medium can be changed according to the respective distance settings between the duplicate recording medium and the master hologram recording medium in the hologram duplication optical system. The method for producing a multiple exposure hologram according to any one of the above items.   6. The method for producing a multiple exposure hologram according to claim 1, wherein the recording medium comprises a photosensitive layer containing a silver salt emulsion having a main particle diameter of 18 to 28 nm.   The method for producing a multiple exposure hologram according to any one of claims 1 to 6, wherein the exposure amount ratio among R, G, and B is substantially the same for the white balance of the recording medium. A hologram produced by the multiple exposure hologram production method according to any one of claims 1 to 7,
A multi-exposure hologram in which light interference by a plurality of light interference exposure means including an analog method is recorded on one recording medium.

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