JP2006011185A - Image display apparatus, image recording medium, and image recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hologram which can be made small in size, lightweight and advantageous for carrying or storage and which can reproduce an image with favorable contrast. <P>SOLUTION: A transparent cover film 2 is applied in the observer side of a hologram recording layer (holographic stereogram) 1. A light direction controlling layer 8 is formed in the opposite side of the hologram recording layer 2 to the observer side, and a holographic optical element 4 is stuck to the light direction controlling layer 8. A transparent cover film 5 is laminated on the holographic optical element 4. Collimated light is made to enter the cover film 5, and the incident light propagates through the cover film 5, the holographic optical element 4 and the light direction controlling layer 8 functioning to introduce the light to the hologram recording layer 1 to reproduce a two-dimensional or three-dimensional image. By arranging the holographic optical element 4, light can be made to enter on the interface at an angle such as 60°. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image display device, an image recording medium, and an image recording method for reproducing a two-dimensional or three-dimensional image from a hologram or holographic stereogram in which two-dimensional or three-dimensional image information is recorded.

  It is possible to synthesize a hologram for reproducing a three-dimensional image using a two-dimensional image of a subject viewed from different viewpoints as an original image. A holographic stereogram, for example, records a large number of images obtained by sequentially photographing a subject from different observation points as original images and sequentially records them as a strip or dot element hologram on a single hologram recording medium. It is produced by doing.

  For example, in the holographic stereogram having parallax information only in the horizontal direction, as shown in FIG. 18, a plurality of original images 101a to 101e obtained by sequentially photographing the subject 100 from different observation points in the horizontal direction are recorded. It is manufactured by sequentially recording on the hologram recording medium 102 as a strip-shaped element hologram by the apparatus.

  In this holographic stereogram, image information obtained by sequentially capturing images from different observation points in the horizontal direction is sequentially recorded in the horizontal direction as strip-shaped element holograms. When viewed with both eyes, the two-dimensional images shown in the left and right eyes are slightly different. As a result, the observer feels parallax and a three-dimensional image is reproduced. Hereinafter, the term including a holographic stereogram is simply referred to as a hologram.

  By the way, a normal hologram can be classified into a reflection type and a transmission type depending on whether the illumination light source is placed on the same side as the observer or on the opposite side with respect to the medium.

  The reflection type has interference fringes with an angle close to parallel to the material surface inside the recording material, so the wavelength selectivity by Bragg diffraction is high and it can be reproduced clearly even when irradiated with white light. The trouble of having to arrange the light source on the front surface remains.

  On the other hand, although the transmissive type can be made into a backlight, there is a problem that the wavelength selectivity is lowered and the light source enters the eyes of the observer when looking into it, resulting in a decrease in contrast.

  In addition, there is a hologram called an edge-lit method in which illumination light is input from the end face of a hologram, which is classified as an intermediate between the reflection type and the transmission type. That is, it is a hologram that illuminates at an illumination light angle exceeding the critical angle inside the material.

  With this edge-lit system, it is possible to realize a compact light source-integrated hologram reproducing apparatus that is more wavelength selective than the transmission type.

  When producing a transmission hologram in which a three-dimensional image is reproduced by light transmitted through a recording medium by the edge lit method, as shown in FIG. 19, it is made of a transparent material such as glass or plastic having an appropriate thickness. The hologram recording medium 111 is attached to one surface 110 a of the light introducing block 110. At this time, the hologram recording medium 111 is usually attached to the light introduction block 110 via an index matching liquid (not shown) in order to prevent total reflection of light. Then, the object light 114 from the subject 113 is irradiated toward the hologram recording medium 111 from the other surface 110b of the light introduction block 110, and the reference light 115 is emitted from the end surface 110c of the light introduction block 110 to the hologram recording medium 111. Irradiate toward. Thereby, a transmission type edge-lit hologram is produced.

  Then, when reproducing the transmission-type edge-lit hologram thus produced, conventionally, a hologram is obtained by attaching a light introduction block such as glass to a hologram recording medium and entering illumination light from the end face of the light introduction block. Was playing. Specifically, as shown in FIG. 20, after the hologram 121 is attached to one surface 120a of the light introduction block 120 via an index matching liquid (not shown), the reproduction illumination light is applied from the end surface 120b of the light introduction block 120. 123 is irradiated toward the hologram 121. At this time, the light transmitted through the hologram 121 is diffracted by the hologram 121. Then, the reproduced image 125 is generated by the diffracted light 124, and the reproduced image 125 is observed by the observer 126.

  In FIG. 20, as an example, the incident angle of the reproduction illumination light 123 to the hologram 121 is set to 60 degrees inside the light introduction block 120. In this way, by introducing the reproduction illumination light 123 through the light introduction block 120, it is possible to prevent surface reflection between the hologram recording material and the air, and this effect is particularly significant as the light incident angle becomes steep. Since it is remarkable, the edge-lit hologram is considered to be advantageous in realizing a compact reproducing apparatus.

  By the way, in the configuration in which the light introduction block 120 is attached to the hologram 121 as shown in FIG. 20, the hologram 121 itself is integrated with the light introduction block 120. Inconvenient. It was also inconvenient for storage.

  For example, as described above, when the incident angle of the reproduction illumination light 123 to the hologram 121 is 60 degrees inside the light introduction block 120 and the length L of the hologram 121 is 30 mm, one of the light introduction blocks 120 If the length of the surface 120a is at least close to the length L, the thickness of the light introduction block 120 on the end surface 120b side needs to be 17.3 mm or more.

  Further, the plurality of holograms to be reproduced by the edge lit method is further inconvenient for carrying and so on, and is also inconvenient for storage and the like. Since one light introduction block is required for each hologram, the same number of light introduction blocks having a thickness of 17.3 mm are required for a plurality of holograms.

  Although it is possible to separate the hologram and the light introduction block, there is inconvenience that cannot be seen unless the observer replenishes the index matching liquid.

  In order to solve this problem, the invention described in Patent Document 1 below has been proposed. That is, as shown in FIG. 21, the hologram 121 is bonded to the back side 131b of the optical member 131 having a stepped unevenness on the front side 131a, and the illumination light 132 is incident from the front side 131a at a predetermined angle, for example, 60 degrees. Let The optical member 131 is formed of, for example, optical glass or transparent plastic, and a plurality of light incident surfaces 133 on which the illumination light 132 is incident vertically are formed on the surface side 131a. In this optical member 131, the incident angle θ of the illumination light 132 with respect to the interface 134 with the hologram 121 is set to an angle at which surface reflection can be suppressed at the interface 134, for example, 60 degrees.

JP 2002-040911 A

  In the method described in Patent Document 1, if the stepped irregularities cannot be formed with high accuracy, light scattering and refraction at the corners and corners occur, and the image is not bright and shines brightly. There was a problem of decreasing.

  This is a problem during reproduction, but there was also a problem during recording. That is, the reference light at an angle exceeding the critical angle causes total reflection at the interface between the medium and air, and allows extra light to stay inside the medium. This extra light forms unnecessary interference fringes that are not necessary for reproducing an image, and there is a problem in that the diffraction efficiency is lowered and the image quality is deteriorated.

  The object of the present invention is to solve such problems. That is, the object of the present invention is to reduce the size and weight as compared with the reproduction of the edge-lit hologram using the light introduction block, which is advantageous for carrying and storage. Further, the stepwise light introduction member previously proposed is used. An object of the present invention is to provide a high-quality image display device, an image recording medium, and an image recording method that solve various problems in recording / reproducing an edge-lit hologram.

In order to solve the above-described problem, a first aspect of the present invention is an image display device that displays image information of a moving image or a still image in a holographic manner.
A holographic medium displaying an image by being illuminated at an angle exceeding a critical angle inside the medium;
A holographic optical element pasted so as to be in optical contact with the surface of the holographic medium opposite to the viewer without passing air;
An image display device having a light source disposed on a side opposite to an observer of a holographic medium.

  Further, in the image display device according to the present invention, the light control layer for controlling the light transmission direction is optically contacted between the hologram or the holographic stereogram and the light-introducing holographic optical element similarly without air. It may be pasted to do. The interval and angle of the light control layer coincide with the angle of the reference light of a hologram or holographic stereogram for recording a so-called image. The louver is preferably formed of a black or dark color in order to increase the contrast with the hologram image.

  The image display device according to the present invention forms a cylinder with the outer side of the image hologram medium in a state where the light-introducing holographic optical element or louver film is bonded to the hologram or holographic stereogram, and the inside of the cylinder A two-dimensional or three-dimensional image may be reproduced by causing illumination light to enter. As a result, an image display device that reproduces the cylindrical edge-lit hologram is obtained.

  In addition, the image display device according to the present invention may include a dedicated light source so that illumination can be performed at a predetermined wavelength from a predetermined position and a predetermined angle. The light source is an LED (Light Emitting Diode) or laser having a peak wavelength near the wavelength that is most efficiently diffracted when reproduced with white light. These light sources may use a plurality of different wavelengths and can be displayed in full color. In addition, these light sources may be shifted so that the color balance does not change even if the observation position is changed up and down with respect to the hologram.

  The hologram image portion is not already recorded on the recording medium, and an interference fringe display device such as a liquid crystal may be used. In that case, a moving image can be displayed.

According to a second aspect of the present invention, in an image recording medium for recording an image,
A holographic recording layer that records an image in a holographic manner, a light direction control layer that controls the direction of light, and a holographic optical element that bends the direction of light are stacked in this order and are in optical contact. This is an image recording medium.

  In the image recording medium according to the present invention, a protective layer, an adhesive layer, and an intermediate barrier layer may be provided between the holographic recording layer, the light direction control layer, and the holographic optical element. A holographic recording layer having a refractive index of 0.2 or less, a low birefringence, and a high transmittance is used.

  The holographic optical element layer is made in advance so that the light matches the angle of the light direction control layer inside the medium in accordance with the light source arranged at a predetermined position.

According to a third aspect of the present invention, a holographic recording layer for recording an image in a holographic manner, a light direction control layer for controlling the direction of light, and a holographic optical element for bending the direction of light are laminated in this order. And using an image recording medium in optical contact,
Hologram or holographic by making the light introduction block optically contact the image recording medium on the same side as the object light and making the reference light with an angle exceeding the critical angle incident on the medium from the same side as the object light. An image recording method is characterized in that a stereogram is recorded.

  According to the present invention, compared with the reproduction of an edge-lit hologram using a conventional light introduction block, the contrast can be greatly improved and a noise-reduced image can be reproduced, which is reduced in size and weight, and is advantageous for carrying and storage. A playback device can be provided. Moreover, not only can the illumination light from the light source be handled as ideal light, but also the fact that the angle at which the light strikes changes depending on the location. Furthermore, a cylindrical edge-lit hologram can be configured. As a positional relationship, it is possible to record and reproduce a hologram with good wavelength selectivity utilizing the edge-lit characteristics, although it can be reproduced as easily as a transmission hologram. . In addition, when applied to a moving image holographic display device, a display device with high brightness and high contrast and high image quality can be configured compactly.

  Hereinafter, several specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. Needless to say, the present invention is not limited to the following examples and can be arbitrarily changed without departing from the gist of the present invention.

  First, the image reproducing apparatus according to the first embodiment will be described. In FIG. 1, reference numeral 1 indicates a holographic medium (hereinafter appropriately referred to as a hologram recording layer). The hologram recording layer is, for example, a holographic stereogram on which a three-dimensional image is recorded. A transparent cover film 2 as a protective layer is attached to the observer side of the hologram recording layer 1. The holographic optical element 4 is bonded so that the surface of the hologram recording layer 1 opposite to the viewer is in optical contact with no air. In the example of FIG. 1, a holographic optical element 4 is bonded to the hologram recording layer 1 via a blocking layer 3 as an intermediate barrier layer. A transparent cover film 5 is bonded to the holographic optical element 4.

  FIG. 2 shows a reproducing apparatus for reproducing an image recorded on the hologram recording layer 1. Parallel illumination light 6 from a light source (not shown) is incident from the cover film 5 side. The incident light is incident on the hologram recording layer 1 through the cover film 5, the holographic optical element 4 that performs the light introduction function, and the blocking layer 3, and a two-dimensional or three-dimensional image can be reproduced.

Here, the refractive indexes n of the cover films 2 and 5, the holographic optical element 4, the blocking layer 3, and the hologram recording layer 1 are 1.5. The refractive indexes of these elements are preferably in the range of a difference of 0.2 or less. When the parallel light 6 is illuminated in air at an angle of 50 degrees with respect to the material normal, first, inside the cover film 5 refracts inward at 30.7 degrees inside the material according to Snell's law. This angle is an angle with respect to the normal to the interface 7. Snell's law is (n1 sin θ1 = n2 sin θ2) where n1 is the refractive index of the medium of the incident light, n2 is the refractive index of the medium of the refractive light, θ1 is the incident angle, and θ2 is the refractive angle.
It is represented by

  Here, by arranging the holographic optical element 4, the angle of incident light is changed to 60 degrees inside the material. In a material having a refractive index of 1.5, the critical angle is about 41.8 degrees, so that it is usually impossible to enter from an end face other than the end face at an angle such as 60 degrees. By using it, it becomes possible to enter from the interface 7.

  The holographic optical element 4 has characteristics such as being able to perform arbitrary wavefront conversion including lens action. As shown in FIG. 3, the holographic optical element 4 can be manufactured by optically contacting the light introduction block and recording the interference fringes by causing the two light beams to interfere with each other. Although the holographic optical element 4 has wavelength dependency, since the present invention performs recording / reproduction with a predetermined wavelength (single wavelength, three primary color light, etc.), the influence of the wavelength dependency of the holographic optical element 4 Can be reduced.

  Now, in the blocking layer 3, the illumination light that has become parallel light of 60 degrees is diffracted when passing through the hologram recording layer 1 to generate a reproduced image, and this reproduced image is observed by the observer 10. .

  Therefore, by using the image reproducing apparatus according to the first embodiment, it is possible to reduce the size and weight as compared with the reproduction of the edge-lit holographic stereogram using the conventional light introduction block, and it is advantageous for carrying and storage. It becomes.

  Next, a configuration example of a system for creating a hologram recording layer 1 such as a holographic stereogram, which is reproduced by the image reproducing apparatus of the first embodiment, will be described with reference to FIG. In the following description, a holographic stereogram having parallax information in the horizontal direction and the vertical direction by recording a plurality of dot-shaped element holograms on one recording medium will be described as an example. However, it goes without saying that the present invention is applicable to a holographic stereogram having lateral parallax information by recording a plurality of strip-shaped element holograms on one recording medium. . At the time of recording, a holographic recording layer as described above and a holographic optical element that bends the direction of light are laminated in this order, and an image recording medium that is in optical contact is used. On the other hand, the light introduction block is brought into optical contact with the same side as the object light, and the reference light having an angle exceeding the critical angle is incident on the medium from the same side as the object light.

  This holographic stereogram creation system is a system for creating a so-called one-step holographic stereogram in which a hologram recording medium in which interference fringes between object light and reference light are recorded is used as it is. A data processing unit 11 that processes target image data, a control computer 12 that controls the entire system, and a holographic stereogram printer device 13 having an optical system for creating a holographic stereogram. Yes.

  The data processing unit 11 includes a plurality of pieces of image data D1 including parallax information supplied from a parallax image sequence photographing device 23 including a multi-view camera, a mobile camera, and the like, and parallax generated by the image data generation computer 24. A parallax image sequence D3 is generated based on a plurality of pieces of image data D2 including information.

  Here, the plurality of pieces of image data D1 including the parallax information supplied from the parallax image sequence photographing device 23 is obtained by converting a real object in the horizontal direction by, for example, simultaneous photographing with a multi-lens camera or continuous photographing with a mobile camera. It is image data for a plurality of images obtained by photographing from a plurality of different observation points.

  The plurality of pieces of image data D2 including the disparity information generated by the image data generation computer 24 are, for example, a plurality of CAD (Computer Aided Design) images and CG (Computer Graphics) that are created by sequentially giving disparity in the horizontal direction. ) Image data such as an image.

  Then, the data processing unit 21 performs predetermined image processing for holographic stereogram on the parallax image sequence D3 by the image processing computer 21. Then, the image data D4 subjected to the predetermined image processing is recorded in the storage device 22 such as a memory or a hard disk.

  In addition, when the image is recorded on the hologram recording medium, the data processing unit 11 sequentially reads out the data for each image from the image data D4 recorded in the storage device 22, and uses the image data D5 for control. Send to computer 12.

  On the other hand, the control computer 12 drives the holographic stereogram printer device 13 to record an image based on the image data D5 supplied from the data processing unit 11 in the hologram recording set in the holographic stereogram printer device 13. It records sequentially on the medium 30 as an element hologram.

  At this time, the control computer 12 controls the shutter 32, the display device 41, the recording medium feeding mechanism, and the like provided in the holographic stereogram printer device 13. That is, the control computer 12 sends a control signal S1 to the shutter 32 to control the opening / closing of the shutter 32, supplies the display device 41 with the image data D5, and supplies the display device 41 with an image based on the image data D5. And a control signal S2 is sent to the recording medium feeding mechanism to control the feeding operation of the hologram recording medium 30 by the recording medium feeding mechanism.

  The optical system of the above-described holographic stereogram printer device 13 will be described in more detail with reference to FIG. FIG. 5 is a view of the entire optical system of the holographic stereogram printer device 13 as viewed from above.

  As shown in FIG. 5, the holographic stereogram printer device 13 includes a laser light source 31 that emits laser light having a predetermined wavelength, a shutter 32 arranged on the optical axis of the laser light L1 from the laser light source 31, and a mirror. 38 and a half mirror 33. Here, for example, a laser light source 31 that emits laser light having a wavelength of about 532 nm is used.

  The shutter 32 is controlled by the control computer 12 and is closed when the hologram recording medium 30 is not exposed, and is opened when the hologram recording medium 30 is exposed. The half mirror 33 is for separating the laser light L2 that has passed through the shutter 32 into reference light and object light. The light L3 reflected by the half mirror 33 becomes reference light, and the half mirror 33 The light L4 that has passed through becomes object light.

  The light L3 reflected by the half mirror 33 is reflected by the total reflection mirror 36, enters the light introducing block 37, and reaches the photosensitive material 30 via the index matching liquid. At this time, on the optical axis of L3, as an optical system for the reference light, an optical system that forms an aperture on the photosensitive material by forming a stop as in the case of object light described later may be formed.

  Here, the hologram recording medium 30 is arranged so as to be in contact with the light introduction block 37 made of transparent glass via a matching liquid so that the element hologram is recorded by the edge-lit method. Then, the reference light enters the hologram recording medium 30 from the side where the light introduction block 37 is disposed.

  That is, the reference light enters the light introduction block 37 from the end surface 37a of the light introduction block 37 and is incident on the hologram recording medium 30 arranged so as to be in contact with the light introduction block 37 via the matching liquid. Incident at the corner.

  On the other hand, on the optical axis of the light L4 that has passed through the half mirror 33, a spatial filter 39 that combines a convex lens and a pinhole for shaping the transmitted light from the half mirror 33 as an optical system for object light, and an object A collimator lens 40 for converting the light into parallel light, a total reflection mirror 38 for reflecting the beam, a display device 41 for displaying an image to be recorded, and a diffusion plate 42 for diffusing the light transmitted through the display device 41. The lens 43 for condensing the object light on the hologram recording medium 30, the aperture 46, the lens 44, and the lens 45 are arranged in this order.

  The light L4 that has passed through the half mirror 33 is reflected by the total reflection mirror 38, and then is diffused from the point light source by the spatial filter 39. Next, the light is collimated by the collimator lens 40, reflected by the mirror 38 and incident on the display device 41. Here, the display device 41 is, for example, a transmissive image reproducing device including a liquid crystal display, and is controlled by the control computer 12 to display an image based on the image data D5 sent from the control computer 12. The light transmitted through the display device 41 is modulated according to the image displayed on the display device 41, diffused by the diffusion plate 42, and then enters the lens 43. Here, the diffusion plate 42 contributes to the improvement of the image quality of the produced holographic stereogram by slightly diffusing the transmitted light from the display device 41.

  The light transmitted through the display device 41 is converged in the lateral direction by the lens 43 and enters the hologram recording medium 30 as object light. That is, in the holographic stereogram printer device 13, the projection light from the display device 41 enters the hologram recording medium 30 as a strip-like object light. Here, the object light enters the hologram recording medium 30 from the side where the light introduction block 37 is not disposed so that the optical axis is substantially perpendicular to the surface of the hologram recording medium 30.

  In the optical system, the optical path length of the reference light reflected by the half mirror 33 and incident on the hologram recording medium 30 through the light introduction block 37 and the half light 33 is transmitted, and the hologram is transmitted through the display device 41. The optical path length of the object light incident on the recording medium 30 is approximately the same length. Thereby, the coherence between the reference light and the object light is increased, and a holographic stereogram capable of obtaining a clearer reproduced image can be produced.

  In the holographic stereogram printer device 13, a mechanism for dropping an index matching liquid between the light introduction block 37 and the hologram recording medium 30 for index matching between the light introduction block 37 and the hologram recording medium 30. Is preferably provided. Specifically, for example, a sponge infiltrated with an index matching liquid is disposed in the vicinity of a portion where the light introduction block 37 and the hologram recording medium 30 are in contact with each other so as to contact the hologram recording medium 30. Thus, every time the hologram recording medium 30 is sent, an index matching liquid is supplied from the sponge between the light introduction block 37 and the hologram recording medium 30, and the light introduction block 37 and the hologram recording medium 30 are Index matching will be achieved.

  At this time, the light incident on the light introduction block as the reference light interferes with the object light in the recording layer and goes straight after being used for hologram recording. However, when this invention is not used, as shown in FIG. The light incident at a critical angle or more undergoes total reflection at the interface with the air layer, such as the hologram recording layer (recording layer) 1 or the blocking layer 3. Since the totally reflected beam reaches the hologram recording layer 1 again, energy other than the original recording of the hologram is applied to cause instability of the image.

  However, if the holographic optical element 4 as shown in FIG. 7 is formed not only at the time of reproduction but also at the time of recording, most of the light that causes total reflection is bent by diffraction and is outside the recording layer 4. Will come out. Thereby, unnecessary stagnation can be avoided and the contrast of the image is improved.

  The holographic stereogram printer 13 includes a recording medium feeding mechanism capable of intermittently feeding the hologram recording medium 30 by one element hologram under the control of the control computer 12. This recording medium feeding mechanism is capable of intermittently feeding a film-like hologram recording medium based on a control signal from the control computer 12. When the holographic stereogram printer device 13 produces a holographic stereogram, each image data in the parallax image sequence is stored in the hologram recording medium 30 set in the recording medium feeding mechanism in a predetermined state. Images based on it are sequentially recorded as element holograms.

  In the above, the system which produces the holographic stereogram reproduced | regenerated by the image reproduction apparatus (refer FIG. 2) of 1st Embodiment was demonstrated.

  Next, an image reproduction apparatus according to the second embodiment will be described with reference to FIG. This second embodiment has the same configuration as that of the first embodiment, except that an optical direction control layer 8 is provided between the hologram recording layer 1 and the holographic optical element layer 4 for introducing light. Is to form.

  As shown in FIG. 9A, FIG. 9B, and FIG. 9C, a film in which a physically interdigital louver 9a is formed between cover materials 9b and 9c such as a PET film is also called a light control film and is already commercially available. ing. This louver film has a large number of louvers provided vertically. 9A and 9B show a state where the louver film is opposed to the planar light source 9d. FIG. 9A shows a case where the visible angle is controlled to 60 degrees, and FIG. 9B shows a case where the visible angle is controlled to 90 degrees. For example, a louver film is used as an application for sticking a louver film to a display surface of a mobile phone and preventing it from being looked into.

  When used as the light direction control layer 8 of the second embodiment of the present invention, the angle of the louver 9a coincides with the in-material reference light angle during recording and the ideal reference light angle during reproduction. For example, when these angles are set to 60 degrees, a louver film having a configuration in which the louver is inclined at an angle of 30 degrees between the cover materials 9b and 9c is used.

  FIG. 10 shows an example in which cover films 2 and 5 and blocking layers 3a and 3b having substantially the same refractive index as those of the functional layers are provided in the middle of the functional layers. Actually, such a configuration is obtained in the film manufacturing process for creating such a laminated structure, but optically, it may be replaced with the simple model of FIG.

  In FIG. 10, when the image is observed during reproduction due to the presence of the light direction control layer 8, the louver (blade) as the light direction control layer 8 is seen in the portion without the image, and the louver is formed in black. If this is done, the background becomes black and an image with high contrast can be observed.

  Even if the light direction control layer 8 is formed from the time of recording, it has no adverse effect on the recording of the required hologram. On the contrary, since the reflection of unnecessary beams is suppressed by the light direction control layer 8 more than that in the first embodiment, it is possible to suppress noise and decrease in diffraction efficiency due to unnecessary interference fringes.

  As a further merit, a degree of freedom is added to the position and parallelism of the light source of the reproducing apparatus. In the case of the first embodiment, when the light source direction is looked into from the hologram, the light source can be seen. Therefore, it is necessary to consider that the light source is placed at a position where it is difficult to enter the eyes. FIG. 11A shows an optical path when reproducing using the holographic optical element 4, and FIG. 11B shows an optical path when creating the holographic optical element 4.

  Further, since the background is bright, there is a problem that it is difficult to obtain image contrast. For example, as shown in FIG. 12A, when parallel light is illuminated from the normal direction of the hologram and from the side opposite to the observer, the light source itself can be seen if a louver of a predetermined reference light / illumination light angle is arranged. Therefore, a high-contrast hologram image can be observed. Illuminating from this position has the advantage that a bright hologram with high light utilization efficiency can be reproduced because surface reflection at the interface between the substrate and air is minimized during observation. The holographic optical element 4 used at this time can be created by an optical system as shown in FIG. 12B.

  As another example, as shown in FIG. 13A, it is also possible to arrange a diffused light source with a point light source at a certain distance from the normal direction of the hologram. According to the position where this point light source is disposed, a holographic optical element may be prepared in advance using an optical system as shown in FIG. 13B using conjugate light. By doing so, it is possible to omit the collimating optical system and to realize a more compact reproducing apparatus at a low cost.

  When the second embodiment is configured more specifically, the reproducing apparatus includes a light source, a housing portion thereof, a viewer including a medium holding portion, an image-recorded hologram, a louver, a holographic optical element, and protection thereof. It is configured to be separated into a medium including a layer, a blocking layer, and an adhesive layer, and can be fixed to the viewer at the same position even if the medium is removed. By adopting such a structure, a plurality of media can be replaced and set in a viewer for observation.

  In addition, when the medium is removed, it is preferable to incorporate an interlock switch mechanism so that power is not supplied to the light source unless the medium is set in the viewer so that the observer does not directly see the light source that is emitting light. .

  By the way, the type and arrangement position of the light source are not necessarily one type, and when there are a plurality of patterns, the optimum holographic optical element changes accordingly, so the specifications of the viewer and the specifications of the medium are as follows: It is necessary to respond. For this reason, the viewer and the medium are devised in shape, and cannot be mounted unless the combinations match. For example, when a convex portion exists on the medium side and a concave portion exists on the viewer side and they do not match, the medium cannot be mounted, and the light source is not activated by the interlock mechanism.

  In addition, since the medium has front and back sides, the shape is devised so that it cannot be mounted conversely. In other words, the above-mentioned convex concave portion is made asymmetrical so that it cannot be reversed.

  Next explained is the third embodiment of the invention. The third embodiment is also an image reproducing device. A cylindrical image reproducing device is formed by the holographic stereogram and the light-introducing holographic optical element used in the first or second embodiment. A cylindrical holographic stereogram is reproduced by a type image reproducing apparatus.

  Specifically, as shown in FIG. 14, the film 51 in which the holographic stereogram 1, the light direction control layer 8, and the light introducing holographic optical element 4 shown in FIG. To form a cylindrical edge-lit holographic stereogram 52. Then, as shown in FIG. 15, a light source 53 is disposed inside the cylindrical edge-lit holographic stereogram 52 to reproduce a three-dimensional image.

  That is, in this cylindrical image reproducing apparatus, a cylindrical edge-lit holographic stereogram 52 is obtained by bending a set 51 of the holographic stereogram 1 and the holographic optical element 4 made for a plane into a cylindrical shape. create. Illumination light emitted from the light source 53 for the cylindrical edge-lit holographic stereogram 52 is converted by the holographic optical element 4 to become parallel light at an angle of 60 degrees inside the material, and an object exists in the cylinder. It is possible to obtain a three-dimensional image as if it were. As in the configuration shown in FIG. 1, a cylindrical image reproducing apparatus can be similarly configured using a medium that does not have a light direction control layer.

  Next, a fourth embodiment will be described with reference to FIG. Although the fourth embodiment is also an image reproducing device, as well as reproducing a recorded holographic stereogram or hologram as described above, it is a device capable of displaying a moving image hologram. For example, when a liquid crystal panel having a pixel interval of micron order or less is used, a diffraction image can be displayed while being rewritten at a certain refresh rate by interference fringes. The second embodiment is applied to this configuration. That is, the light direction control layer 8 having the louver film and the light introducing holographic optical element 4 are arranged on the opposite side of the transmissive liquid crystal panel 61 from the observer, and the light source is installed behind the air layer.

  Next, a fifth embodiment will be described. As shown in FIG. 17, the light direction control layer 8 and the holographic optical element 4 are arranged inside the cylindrical liquid crystal panel 61 from the outside to the inside, and the light source 62 is arranged at the center of the cylinder. A cylindrical moving image hologram display can be formed.

  As mentioned above, although each embodiment of this invention was described concretely, this invention is not limited to the above-mentioned embodiment, The various deformation | transformation based on the technical idea of this invention is possible. For example, in the fourth embodiment and the fifth embodiment described above, an example in which a liquid crystal panel is used as the image hologram display device has been described. However, other types of spatial light modulators are possible as long as they are spatial light modulators. is there.

  As an example of the present invention, a single color has been described, but a color is also possible. Even if the light source is white light, it is possible to reproduce the color by selecting the wavelength according to the Bragg diffraction condition of the edge-lit hologram itself. However, even if a plurality of light sources such as R, G, and B are used, color display is possible. A device and a playback device can be configured. In the case of an already recorded hologram or holographic stereogram reproducing apparatus, a light source having a wavelength component close to the recording wavelength is desirable. Actually, the reproduction wavelength often shifts from the recording wavelength depending on the characteristics of the recording material, but in general, a good image was obtained when reproduced with a light source having a peak wavelength of about ± 30 nm from the recording wavelength. When arranging multiple light sources for color reproduction, the color balance of the reconstructed image will not be lost even if the viewpoint is changed up and down by arranging the light source positions obliquely according to the wavelength. Can do. In the example of the present invention, R, G, and B semiconductor lasers were arranged at positions satisfying this so-called achromatic angle, and a good reproduced image could be obtained.

  The application of the image reproducing apparatus of the present invention is not limited to reproducing a hologram or holographic stereogram in which three-dimensional image information is recorded, but a hologram or holographic in which two-dimensional image information is recorded. It can be applied when playing back a stereogram.

1 is a schematic diagram showing a hologram reproducing device according to a first embodiment of the present invention. It is a basic diagram for demonstrating the hologram reproduction apparatus by 1st Embodiment of this invention. It is a basic diagram which shows the optical path when producing the holographic optical element used for this invention. It is an approximate line figure showing an example of 1 composition of a holographic stereogram creation system. It is a basic diagram which shows an example of the optical system of a holographic stereogram printer apparatus. It is a basic diagram used for description of the optical path when not providing a holographic optical element. It is a basic diagram used for description of the optical path at the time of providing a holographic optical element. It is a basic diagram which shows the hologram reproduction apparatus by 2nd Embodiment of this invention. It is a perspective view for demonstrating the light direction control layer used for the 2nd Embodiment of this invention. It is a basic diagram which shows the hologram reproduction apparatus by 2nd Embodiment of this invention. It is a basic diagram which shows the function when reproducing | regenerating using the holographic optical element of this invention, and a schematic diagram which shows the optical path when producing the holographic optical element. It is a basic diagram which shows the function when reproducing | regenerating using the holographic optical element of this invention, and a schematic diagram which shows the optical path when producing the holographic optical element. It is a basic diagram which shows the function when reproducing | regenerating using the holographic optical element of this invention, and a schematic diagram which shows the optical path when producing the holographic optical element. It is a basic diagram which shows the formation method of the cylindrical edge-lit hologram reproducing apparatus by 3rd Embodiment of this invention. It is a basic diagram which shows the structure of the cylindrical edge-lit hologram reproducing apparatus by 3rd Embodiment of this invention. It is a basic diagram which shows the holographic display device by 4th Embodiment of this invention. It is a basic diagram which shows the holographic display device by 5th Embodiment of this invention. It is a basic diagram which shows the preparation method of a holographic stereogram. It is an approximate line figure showing the creation method of a transmission type edge lit hologram. It is a basic diagram which shows the reproducing method of a transmission type edge lit hologram. It is a basic diagram which shows the structure of the image reproduction apparatus proposed previously.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Hologram recording layer 2 ... Cover film 3 ... Blocking layer 4 ... Holographic optical element 6 ... Illumination light 8 ... Light direction control layer

Claims (16)

In an image display device that displays image information of a moving image or a still image in a holographic manner,
A holographic medium displaying an image by being illuminated at an angle exceeding a critical angle inside the medium;
A holographic optical element pasted so as to be in optical contact with the surface of the holographic medium opposite to the viewer, without passing through air,
An image display device comprising: a light source disposed on a side opposite to an observer of the holographic medium.   Between the holographic medium and the holographic optical element, a light direction control layer corresponding to an illumination light angle necessary for image display is bonded so as to be in optical contact without air. The image display device according to claim 1, wherein:   2. The image display device according to claim 1, wherein the holographic medium is a recorded hologram or holographic stereogram. The holographic medium has a substantially cylindrical shape or a partial shape thereof,
The holographic optical element is bonded to the inside of the holographic medium so as to be in optical contact without air, so that an image can be displayed by light from a light source disposed inside the holographic medium. The image display device according to claim 1, wherein: The holographic medium has a substantially cylindrical shape or a partial shape thereof,
Between the holographic medium and the holographic optical element medium, a light direction control layer corresponding to the illumination light angle required for image display is bonded so as to be in optical contact without air. The image display device according to claim 4, characterized in that:   5. The image display device according to claim 4, wherein the holographic medium is a hologram or a holographic stereogram in which a still image is recorded.   4. The image display device according to claim 3, wherein the reproducing light source is a semiconductor laser having a peak wavelength at ± 30 nm of the recorded wavelength.   4. The image display device according to claim 3, wherein the reproduction light source is a light emitting diode having a peak wavelength at ± 30 nm of the recorded wavelength.   The image display apparatus according to claim 1, wherein the light source is an aggregate of light sources having a plurality of peak wavelengths.   The image display device according to claim 9, wherein a plurality of light sources are arranged at positions satisfying the achromatic angle. In an image recording medium for recording an image,
A holographic recording layer that records an image in a holographic manner, a light direction control layer that controls the direction of light, and a holographic optical element that bends the direction of light are stacked in this order and are in optical contact. An image recording medium characterized by the above.   12. The image recording medium according to claim 11, wherein a protective layer and an intermediate barrier layer are provided, and the refractive index thereof is no more than 0.2 from the refractive index of the holographic recording layer.   12. The image recording medium according to claim 11, wherein the light direction control layer is black.   12. The image recording medium according to claim 11, wherein a shape for discriminating between the front and back sides is provided.   12. The image recording medium according to claim 11, wherein a shape for defining the position and type of the light source to be illuminated is applied. A holographic recording layer that records an image in a holographic manner, a light direction control layer that controls the direction of light, and a holographic optical element that bends the direction of light are stacked in this order and are in optical contact. Using an image recording medium,
A light guide block is optically contacted with the image recording medium on the same side as the object light, and a reference light having an angle exceeding the critical angle is incident on the medium from the same side as the object light to thereby generate a hologram or a hologram. An image recording method comprising recording a graphic stereogram.

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