JP4937147B2 - Information reading method, information reading apparatus and program - Google Patents

Description

  The present invention relates to an information recording technique using a hologram, and more particularly to a technique for reading information in a state where a plurality of recording media are stacked and a technique using the technique.

  As information recording media, magnetic recording type magnetic cards and optical cards, and recently, contact type and non-contact type IC cards are known. In any recording medium, basically, the number of media that can be read simultaneously is one, and a plurality of recording media cannot be read in an overlapping state.

  As a technique for solving such a problem, a device in a non-contact type information recording medium is known (see, for example, publicly known document 1). This technology is based on information reading technology using electromagnetic induction, and the influence of interference between overlapping non-contact information recording media, which causes reading failure in general non-contact information media, It is suppressed by the device of the pattern.

JP 2005-56118 A

  However, a recording medium using electromagnetic induction requires an electronic circuit in which a coil, a chip, etc. are arranged in the medium, and the configuration and manufacturing process of the card are complicated and the price is higher than that of a medium such as a magnetic card. I had to be. SUMMARY An advantage of some aspects of the invention is that it provides a technique that allows a plurality of media to be simultaneously read at a low price with a medium having a simple configuration.

According to the first aspect of the present invention, the first recording medium and the second recording medium are stacked in a state where the first recording medium provided with a recording layer for recording hologram information and the second recording medium are overlapped. The method of reading the hologram information recorded in the step, wherein the reproduction illumination light is irradiated in an oblique or vertical direction on the superimposed surface in a state where the first recording medium and the second recording medium are superimposed. And a step of detecting the first diffracted light from the first recording medium and the second diffracted light from the second recording medium generated by irradiation with the reproduction illumination light in a separated state. And obtaining secondary information relating to the order in which the first recording medium and the second recording medium are stacked based on the first diffracted light and the second diffracted light. This is a characteristic information reading method.

According to a second aspect of the present invention, the first recording medium and the second recording medium are stacked in a state where the first recording medium having a recording layer for recording hologram information and the second recording medium are overlapped. A device for reading hologram information recorded on the recording medium, wherein the first recording medium and the second recording medium are superposed on each other, and reproduction illumination light is irradiated on the superposed surface from an oblique or vertical direction. A state in which the illumination light irradiating means and the first diffracted light from the first recording medium and the second diffracted light from the second recording medium generated by irradiation with the reproduction illumination light are separated. Reproducing light detecting means for detecting the first recording medium and the second diffracted light based on the first diffracted light detecting means for determining the order in which the first recording medium and the second recording medium are stacked; An information reading device comprising:

According to a third aspect of the present invention, the first recording medium and the second recording medium are stacked in a state where the first recording medium having a recording layer for recording hologram information and the second recording medium are overlapped. A program for executing the process of reading the hologram information recorded on the recording medium, wherein the reproduction illumination light is obliquely or perpendicular to the superimposed surface in a state where the first recording medium and the second recording medium are overlapped. A reproduction illumination light irradiating step for irradiating from the direction, a first diffracted light from the first recording medium and a second diffracted light from the second recording medium generated by the irradiation of the reproduction illumination light. Based on the reproduction light detection step for detecting light in a separated state and the first diffracted light and the second diffracted light, the order in which the first recording medium and the second recording medium are overlapped computing and obtaining the secondary information relating to Is a program for causing performed.

According to the above invention, since the reproduction illumination light is irradiated in a state where a plurality of recording media are stacked, the diffracted light generated in each medium is generated from a position shifted from the generation direction of the diffracted light. In other words, when reading hologram information from a plurality of recording media at the same time, the recording media of the plurality of sheets are overlapped and are displaced in the vertical direction. It occurs from a position shifted from the viewpoint. For this reason, the information recorded on each medium can be read simultaneously from the state in which the recording media are stacked.

  In this specification, the hologram information is applied to the photosensitive material from different angles by recording light and reference light modulated based on the information to be written, and the interference state of both lights is fixed to the photosensitive material as interference fringes. To record (write). This record is read out by diffracted light that is generated when the recording light is irradiated with the same light as the reference light at the same angle as the reproduction illumination light (this diffraction light is diffracted by the previous interference fringes). This is done by detecting This diffracted light reflects the state of interference between the recording light and the reference light, and information contained in the recording light is included therein.

In the present invention, the number of identification media to be stacked is not limited to two, and may be three or more. In addition, the direction oblique to the overlapped surface means an angle formed between the direction perpendicular to the overlapped surfaces of the two identification media exceeds 0 degree and less than 90 degrees. The optical axis of the reproduction illumination light may be made coincident or substantially coincident with the optical axis of the reference light used for writing information. The allowable range of the substantially coincidence depends on the thickness of the recording layer, but it is sufficient that the accuracy is ensured within a range of several degrees or less.

According to the present invention, occurrence location of the diffracted light from each of the plurality of sheets of recording medium in a state where the superimposed because deviated position-form, can read the information written on the recording medium optically simultaneously. Because the secondary information, the information recorded in each of the plurality of recording media and the primary information refers to information obtained by combining a plurality of the primary information.

  According to the present invention, there is provided a technology capable of simultaneously reading a plurality of media at a low price with a medium having a simple configuration.

First, an example of the physical configuration of the recording medium will be described. FIG. 1 is a perspective view showing the configuration of the recording medium, and FIG. 2 is a cross-sectional view taken along line XY in FIG. FIG. 1 conceptually shows the recording medium 100. FIG. 2 shows a cross-sectional structure of the recording medium 100. In this example, the recording medium 100 has a card shape. The recording medium 100 has a cross-sectional structure in which a recording layer 102 for recording holography is located in an intermediate part of a base material 101. Specific structures include a structure in which the recording layer 102 is sandwiched between two film-like members constituting the base material, or a recording layer is formed on a film-like base material, which is covered with a transparent protective film. An example of a structure equivalent to the cross-sectional structure shown in FIG. 2 can be given. The recording layer 102 may be disposed at or near the surface portion of the substrate 101.

  In this example, since visible light is used as recording light, reference light, and reproduction illumination light, polycarbonate that transmits visible light with high efficiency is used as the base material 101. Further, a polymer (photopolymer: photosensitive resin) that is sensitive to visible light is used as the recording layer. As the photosensitive resin, diacrylic monomer (FDA) having diphenyl fluorone skeleton as monomer, diallyl phthalate prepolymer (DAPP) as polymer, diethyl sebacate (DES) as plasticizer, photopolymerization started A photoinitiator (BTTB) is used as an agent, and a cyanine dye (CY), a merocyanine (MR) dye or the like is used as a composition material as a sensitizing dye. For example, the blending amount of each material is FDA: 10 to 40% by weight, DAPP: 10 to 40% by weight, DES: 20 to 40% by weight, BTTB: 9 to 18% by weight, CY: 0.05 to 0.1% by weight MR: 0.05 to 0.1% by weight can be used as the photosensitive resin.

  When using visible light, as the base material, a resin material having an equivalent light transmittance can be used in addition to polycarbonate. As the recording layer, a recording layer adjusted so as to be sensitive to the wavelength to be used can be used. In addition, when using infrared light as recording light, reference light, and reproduction illumination light, visible light blocking resin or paper that transmits infrared light can be used as a substrate, and the wavelength of the recording layer can be used. Those prepared so as to be exposed to light can be used. When ultraviolet light is used, a material that transmits ultraviolet light with high efficiency can be used as the substrate, and a material that can be exposed to ultraviolet light to form an image can be used as the recording layer.

An example of a method for manufacturing the recording medium 100 shown in FIGS. 1 and 2 will be described. First, a polycarbonate film having a thickness of 100 μm is prepared. Moreover, the preparation which melt | dissolved said photosensitive resin composition in the solvent is produced, it is apply | coated on the previous polycarbonate film, and a sample is created. The sample is left in a reduced-pressure atmosphere of about 100 to 300 Pa at room temperature, the solvent is blown off, and heating is further performed at 50 ° C. for 5 minutes to form the recording layer 102 composed of the photosensitive resin formed in a layer shape. To do. A suitable value for the thickness of the recording layer 102 varies depending on the intensity of recording light and reference light to be used and the sensitivity of the light detection sensor at the time of reading. In general, the thickness is several tens to several hundreds of μm, but a value obtained experimentally is used as a specific thickness. Next, a layer of a resin material having light transmittance covering the recording layer 102 is formed as a protective layer and integrated with the base material 101. In this way, the recording medium 100 having the cross-sectional structure shown in FIG. 2 is obtained.

Next, the principle of recording information by the recording medium 100 will be briefly described. FIG. 3 is a conceptual diagram showing the principle of recording hologram information on the recording medium 100 shown in FIG. In order to record a phase hologram (hereinafter referred to as a hologram), the same portion of the recording layer 102 is irradiated with recording light and reference light from different angles. The recording light and the reference light are coherent light having the same wavelength. For example, the light from the same coherent light source is divided by a beam splitter, and one is used as recording light and the other is used as reference light.

  The recording light is obtained as a light beam containing desired information by passing the emitted light through a spatial light modulator 103 called SLM (Spatial Light Modulator) and optically modulating the light. The recording layer 102 irradiated with the recording light and the reference light is formed with interference fringes due to mutual light interference. The photosensitive material constituting the recording layer is sensitized by the interference fringes, and the state of the interference fringes is fixed as an optically altered state. Thereby, the information put on the recording light by the spatial light modulator 103 is optically recorded on the recording layer. The interval between the interference fringes is as large as the wavelength of light, and the interference fringes play a role like a diffraction grating.

  The writing of hologram information is performed by recording light modulated by a spatial light modulator (SLM) 103 (specifically, the recording light is partially formed with or without recording light) and the recording light 100 from a different angle together with the reference light. It is done by irradiating. In the recording layer 102, information corresponding to the partial brightness produced by the spatial modulator (SLM) 103 is written (see FIG. 3). This information is recorded as the state of interference fringes formed on the recording layer 102 described above.

  Reading of information written on the recording medium 100 is performed by irradiating the recording layer 102 with reference light (referred to as reproduction illumination light) under the same conditions as when recording, and detecting diffracted light generated at that time. (See FIG. 4). That is, when the recording layer 102 is irradiated with reference light (referred to as reproduction illumination light) under the same conditions as when recording, diffraction occurs in the interference fringes formed in the recording layer 102. The diffracted light generated at this time is in the same state as the recording light in FIG.

  Assuming that the recording light is reflected light from an object, the reproduced diffracted light includes light intensity from each point of the object and information on the distance from each point to the recording layer (phase information). (Reproducing light). Thus, the reproduction light looks three-dimensional rather than two-dimensional, so it looks as if the object is there. Although the diffraction efficiency depends on the type of hologram and the thickness of the recording layer 102, a diffraction efficiency of 80% or more can be realized with a phase hologram recorded on a photopolymer. Generally, when the recording layer is thinned, the diffraction efficiency is lowered and the ratio of transmitted light is increased. As described above, the ratio of the diffracted light and the transmitted light can be adjusted by the thickness of the recording layer.

Here, a spatial light modulator (SLM) 103 using liquid crystal will be described. A spatial light modulator (SLM) 103 using liquid crystal is a transmissive liquid crystal panel, and each pixel arranged two-dimensionally arranged in a matrix functions as an optical shutter. When the emission and emission of the recording light is passed through the spatial light modulator 103 using this liquid crystal, the recording light containing the light and dark information developed one-dimensionally or two-dimensionally is generated. For example, a recording light including a data string in which information corresponding to lightness and darkness corresponding to 0 and 1 is expanded one-dimensionally or matrix data expanded two-dimensionally is generated. FIG. 5 shows an example of information modulated by the spatial light modulator 103. In the example shown in FIG. 5, the recording light includes two-dimensional matrix data determined by a combination of transmission or non-transmission.

  Here, an example of a spatial light modulator using a transmissive liquid crystal panel has been described, but the spatial light modulator may be configured using a mechanical mechanism shutter. It is also possible to apply light to an object and use the reflected light as recording light. In this case, information to be written is constituted by the unevenness of the object.

  An example of recording information on the recording layer 102 is shown in FIG. In this example, the recording light is parallel light and passes through the optical shutter portion of the spatial light modulator 103, so that a band-like light having light and dark forms an image on the surface of the recording medium 100 as recording light. When light different from this recording light is irradiated as reference light from a different angle, bright and dark recording light like a barcode is recorded on the recording layer 102 as hologram information according to the principle shown in FIG. In the figure, the same reference light is applied to the entire surface of the card. In reading this information, since it is important to irradiate the reproduction illumination light on the surface obliquely, the reference light irradiates the surface of the recording medium 100 from an oblique direction as shown in the figure. Note that the recording light is applied to the recording medium 100 at an angle different from that of the reference light in order to cause interference with the reference light. In the figure, an example in which recording light is irradiated from a direction perpendicular to the surface of the recording medium 100 is shown, but the angle is not limited to the illustrated angle as long as the angle is different from that of the reference light. In addition, when recording is performed by irradiating the recording medium 100 with the reference light from various angles, the allowable condition of the irradiation angle of the reproduction illumination light at the time of reading becomes wide.

An example of a method for reading written (recorded) information from the recording medium 100 on which information has been written by the method shown in FIG. 6 will be described. FIG. 7 shows a state in which the recording medium 100 on which the hologram information is written by the method shown in FIG. 6 is irradiated with the strip-shaped reproduction illumination light. In this example, the reference light irradiated on the entire surface of the recording medium in FIG. 6 is used as a reproduction illumination light in the form of a band using an appropriate shutter mechanism or optical system. The reproduction illumination light is irradiated from the same direction as the reference light in FIG. The same shutter mechanism as that used for the spatial light modulator 103 can be used as the shutter mechanism for producing the belt-like beam.

  As shown in FIG. 7, a part of the reproduction illumination light applied to the recording medium 100 is diffracted into a diffracted light in the region where the hologram information of the recording layer 102 is written, and the other part is transmitted light as the recording medium 100. Transparent. At this time, the diffracted light is reproduced in the same direction as the recording light in FIG. The reproduced diffracted light reproduces the light / dark information of the recording light. Therefore, by changing the combination of light and dark, it becomes possible to record information unique to each recording medium. 7 is a perspective view, while FIG. 8 is a cross-sectional view seen from the side. Usually, the reproduction light forms an image at a position separated from the recording layer 102 by the same distance as the distance between the shutter mechanism and the recording layer 102. However, in this example, since the recording light is parallel light and the reproduction light is also reproduced by the parallel light, the image formation range is extremely wide. That is, the allowable range of the position where the reproduction light can be detected is extremely wide.

The three recording media 111 to 113 on which information is recorded with the reference light under the same conditions as in FIG. 6 are stacked so that there is no deviation, and the reproduction illumination light is irradiated from the same angle as the reference light when the information is written. The situation at the time is shown in FIG. In this case, the reproduction illumination light is irradiated from an oblique direction. The reproduction illumination light first enters the recording medium 111, which is the top medium. Most of the light is transmitted as it is, but a part of the light is reproduced as diffracted light. The diffracted light is reproduced in the same direction as the recording light. In this case, the diffracted light travels in the downward direction perpendicular to the surface of the recording medium 111. This diffracted light passes through the recording media 112 and 113 as they are. Even if other hologram information is written in the areas of the recording media 112 and 113 through which the diffracted light from the recording medium 111 is transmitted, the diffracted light does not satisfy the condition for functioning as reproduction illumination light ( Therefore, the diffracted light from the recording medium 111 passes through the recording media 112 and 113 without being diffracted during transmission. This is due to the fact that the reproduction illumination light has an angle dependency and has a property of transmitting without being diffracted except at the recorded input angle.

  On the other hand, the light transmitted through the recording medium 111 enters the recording medium 112 below. Although the intensity is slightly reduced, the same condition as when the light is incident on the recording medium 111 is maintained. Therefore, the recording medium 112 also functions as reproduction illumination light, and part of the light is reproduced as diffracted light. The light transmitted through the recording medium 112 is further reduced in intensity, but is incident on the recording medium 113 under the same conditions as when incident on the recording media 111 and 112, and further diffracted light is reproduced.

  The belt-shaped reproduction illumination light is irradiated from an oblique direction, is applied to a position on a different surface of each recording medium, and the diffracted light travels in a direction perpendicular to the surface. Therefore, the reproduction light from each recording medium is received by a light receiving device. Are detected at different positions on the light receiving surface. Based on this principle, each diffracted light can be detected independently, and information read from each recording medium can be obtained independently and simultaneously.

  FIG. 10 shows the light receiving device of FIG. 9 as viewed from above. FIG. 10 shows a state in which bar code-like light and dark by each diffracted light is irradiated. When the reproduction illumination light is irradiated obliquely as shown in FIG. 9, each reproduced diffracted light is generated in a shifted state shifted in the horizontal direction. If the thickness of the medium is 0.2 mm and the angle between the reproduction illumination light and the recording medium is 30 degrees, the length of the shift amount of the diffracted light between the recording medium 111 and the recording medium 112 is about 0.35 mm. Become. If it is about this level, it becomes possible to detect with sufficient resolution by a light receiving device (CCD or photodiode array) having a higher resolution.

  Thus, since the reproduction illumination light is incident from an oblique direction, the first diffracted light from the region 111a of the recording medium 111 (exaggerated and widely shown in the drawing) and the region 112a of the recording medium 112 are The second diffracted light and the third diffracted light from the region 113a of the recording medium 113 are obtained. Since these diffracted lights are generated from a region shifted in position, they are simultaneously detected in a state of being shifted without overlapping. Based on the above principle, a system capable of reading information simultaneously in a single sheet state or in a state where a plurality of sheets overlap each other is realized.

  Information read from the state in which the recording media 111 to 113 are stacked according to this principle is information recorded on each recording medium as shown in FIG. 10 developed and arranged on a two-dimensional plane. When information from a plurality of recording media obtained in such a manner is combined to obtain secondary information, areas in each recording medium on which information is recorded and irradiated with reproduction illumination light at the time of reading are shown in FIG. As shown in the regions 111a to 111c, the recording media need to be displaced when they are stacked.

  For example, the recording medium 111 will be described. In the recording medium 111, predetermined information is recorded in a region 111a irradiated with reproduction illumination light when reading information. This predetermined information is combined with hologram information read from other recording media 112 and 113 having a recording layer similar to the recording layer 114, and predetermined secondary information composed of the brightness of the diffracted light shown in FIG. Information. The predetermined area 111a includes a portion where the reproduction illumination light of the recording medium 112 hits and the reproduction illumination light of the recording medium 113 when the hologram information is read by overlapping the recording medium 111 and the other recording media 112 and 113. The contact portion is a positional relationship that does not overlap each other in a state where the recording media are stacked for reading information. This condition can be similarly applied to the other two recording media 112 and 113. By recording information that satisfies this condition, information can be read according to the principle shown in FIG. it can.

  In this example, three recording media are stacked and information is read out, but the number of recording media to be stacked is arbitrary. However, it is necessary to satisfy the condition that the lowermost recording medium is irradiated with reproduction illumination light that generates diffracted light, and the diffracted light from the uppermost recording medium passes through the lowermost recording medium. is there. In other words, a plurality of recording media can be stacked within a range satisfying this condition, and information can be read according to the principle shown in FIG.

An example in which the principle shown in FIG. 9 is used for a game card will be described. In this example, the recording medium of the present invention is applied to a card used for a trading card game. In this example, it is assumed that a battle is performed on a computer game device, and hologram information recorded on a card is read into the computer game device to perform a battle.

  In this example, the cards are roughly divided into several types of cards. Specifically, a character card depicting each character, a weapon armor card depicting weapons and armor used by the character, a command card for attack, defense, magic, etc., an item depicting the item used It is divided into cards. For example, when a character card is placed in a card reader, a character appears on the screen, and when a weapon and armor card is placed on the card, the character equips the weapon and armor. Furthermore, the command card and the item card used in the battle are selected, and the preparation for the battle is completed. After that, the battle starts.

  In the production of a card, a photopolymer to be a holographic recording layer is printed on a polycarbonate substrate by a general-purpose printing method such as offset printing, and an ultraviolet curable protective layer for protecting the recording layer is further printed thereon. The graphic of a character, an item, etc. is printed on it, and a card is completed by punching it into a card shape. When infrared rays are used for reading a record, printing can be performed with ink that transmits infrared rays to conceal the recording layer.

  An example of the reading device is shown in FIG. FIG. 11 shows a reader 120 of a type in which a card place 125 that is inclined obliquely so as to easily stack the cards 121 to 124 is provided, and the cards 121 to 124 are stacked and read one after another. The reader 120 includes a light receiving device 129 that detects the diffracted light group 128. The light receiving device 129 is a photoelectric conversion device that converts light composed of a CCD or a photodiode array into an electrical signal.

  A light receiving data processing device 130 is connected to the light receiving device 129. The light reception data processing device 130 converts the signal output from the light reception device 129 into a predetermined data format and sends it to the information acquisition device 131. The information acquisition device 131 acquires secondary information based on information included in the diffracted light group 128 (that is, information read from the cards 121 to 124). At this time, data recorded in the memory 132 is referred to. This secondary information becomes the setting content of the fighter on the game obtained by the combination of the setting information of the character card, weapon armor card, command card, and item card described above.

  The memory 132 stores an operation program for controlling an operation of reading information from the cards 121 to 124. The information acquisition device 131 has a built-in CPU and controls the entire operation of the reader 120. The secondary information acquired by the information acquisition device 131 is sent to the game control device 133 that controls the operation of the game. The game control device 133 controls the progress of the game based on the secondary information sent from the information acquisition device 131.

Reading of information in this example is performed as follows. First, the cards 121 to 124 having the structure shown in FIGS. 1 and 2, in which information is recorded according to the principle shown in FIG. 6, and the information is written so that the reading principle shown in FIG. 9 can be used. Are placed on the card place 125 of FIG. Next, the reproduction illumination light 127 from the light source 126 is applied from an oblique direction to the surface of each card. The reproduction illumination light 127 is a beam having an elongated strip-like (linear) cross-sectional shape. As a result, 128 groups of diffracted light are generated. The diffracted light group 128 includes four diffracted lights diffracted by each card, and they are generated from positions shifted from each other when viewed from the direction perpendicular to the card surface.

  In the light receiving device 129, four strips of diffracted light from each card are detected in a line. Here, for example, the diffracted light from the card 124 includes information related to the character, the diffracted light from the card 123 includes information related to weapons and armor, and the diffracted light from the card 122 relates to determination of attack, defense, use of magic, etc. It is assumed that the diffracted light from the card 121 includes information on the use of other items. A player (player who plays a game) has a plurality of cards of various types according to differences in characters and weapons. As the game progresses, the player selects a suitable card from among them according to the situation, and superimposes the card on the card place 125 to play against the computer (game machine).

  At this time, the information acquisition device 131 simultaneously reads information from the four stacked cards 121 to 124 and combines the information to acquire the setting (secondary information) selected by the player. For example, the information acquisition device 131 obtains the character information selected by the player based on the information read from the card 124, and obtains information on the weapon and the armor selected by the player based on the information read from the card 123, Further, based on the information read from the card 122, information related to the decision on the attack or defense selected by the player, the use of magic, etc. is obtained, and further on the use of other items selected by the player based on the information read from the card 121. get information. Then, by combining these pieces of information, settings relating to a fighter performing a virtual battle in the game selected by the player are obtained as secondary information. This secondary information is sent to the game control device 133. The game control device 133 recognizes various conditions (information on weapons to be used, etc.) set for the fighter and advances the game based on the settings.

  According to the game method of this game, the player advances the game by selecting the cards to be stacked. At this time, since the selected cards need only be stacked and placed in the card storage area 125, the operation is simplified. In addition, it is possible to make the game machine recognize complex information while performing simple operations.

  The information reading procedure described above is executed according to the operation program recorded in the memory 132. This program can also be provided from an externally connected recording medium or line.

In FIG. 12 , a card box 141 is prepared, a character card 142 is inserted into the character portion 143, a weapon card (not shown) is inserted into the weapon portion 144, and the card is set in each card slot. Thereafter, information is read by setting the card box 141 in a reader (not shown). According to this aspect, if each player has a box, preparations before the battle are facilitated.

  In the example shown in FIG. 9 or FIG. 11, the reproduction illumination light having a belt-like cross-sectional shape is used. However, the spot-like laser light may be irradiated while scanning in the belt-like region. Also, in this example, as shown in FIG. 10, an example has been described in which information is configured by setting two types of light and dark with one dot. However, information corresponding to the gradation between light and dark has been described. Can also be configured.

  In the above example, a case where a game is played against a computer has been described. However, a similar reading means is prepared, and the opponent player also performs a similar operation (an operation for selecting a card) to perform a battle. It can also be. In addition, the game machine having the reader 120 shown in FIG. 4 is connected to a line such as the Internet, and the server computer is played against the line, or the game is played against other users connected to the line. You can also

According to this example, even when a plurality of recording media overlap each other, all the recording media can be read simultaneously. In addition, writing data requires a large optical mechanism, and it is difficult to analyze the recorded data. The analysis requires advanced optical knowledge and a high-precision optical reading system. The tampering prevention effect can be increased. In addition, since the recording layer can be provided inside the card, data is not lost due to friction unlike a barcode. Moreover, even if a magnet is brought close like a magnetic card, data is not lost. In addition, since the reader does not have a drive mechanism, the price can be reduced and the size can be reduced, and the maintenance labor can be greatly reduced. In addition, since the card can be read in a completely stationary state, reading is always possible. In the case of the infrared reading type, the presence of the recording layer can be hidden. Further, printing can be performed on the entire surface of the card, and the design can be improved.

FIG. 13 shows a state in which a recording medium 151 including a recording layer 151a, a recording medium 152 including a recording layer 152a, and a recording medium 153 including a recording layer 153a are stacked. The media 151 to 153 are assumed to have the same physical structure as that of the recording medium 100 described in the first embodiment.

  First, in a state where the recording media 151 to 153 are stacked, the angle shown in FIG. 13A (the angle formed between the line perpendicular to the surface is 45 degrees) at the position shown in FIG. The case of irradiating the strip-shaped reproduction illumination light 154 extending in the depth direction of the figure will be described. In this case, diffracted light is generated from the band-like region 11 of the recording layer 151a in the recording medium 151, and is received by the light receiving surface 155 of the light receiving device. Further, diffracted light is generated from the band-like region 12 of the recording layer 152a in the recording medium 152, and is received by the light receiving surface 155 of the light receiving device. Further, diffracted light is generated from the band-like region 13 of the recording layer 153a in the recording medium 153, and is received by the light receiving surface 155 of the light receiving device. That is, the light receiving surface 155 simultaneously receives diffracted light from the three linear regions 11 to 13 of each recording medium, and information based on these three diffracted lights is obtained by an information acquisition device (not shown). In this case, secondary information based on the information recorded in the area 11 of the recording medium 151, the information recorded in the area 12 of the recording medium 152, and the information recorded in the area 13 of the recording medium 153. Is read.

  When the reading of information in the state shown in FIG. 13A is completed, the reproduction illumination light is then irradiated to a position shifted by a predetermined distance from the position of FIG. This is shown in FIG. In this case, diffracted light is generated from the band-like region 21 of the recording layer 151a in the recording medium 151, and is received by the light receiving surface 155 of the light receiving device. In addition, diffracted light is generated from the band-like region 22 of the recording layer 152a in the recording medium 152, and is received by the light receiving surface 155 of the light receiving device. Further, diffracted light is generated from the band-like region 23 of the recording layer 153a in the recording medium 153, and is received by the light receiving surface 155 of the light receiving device. In other words, the light receiving surface 155 simultaneously receives the diffracted light from the three belt-like regions 21 to 23 of each recording medium, and information based on these three diffracted lights is obtained by an information acquisition device (not shown). In this case, secondary information based on the information recorded in the area 21 of the recording medium 151, the information recorded in the area 22 of the recording medium 152, and the information recorded in the area 23 of the recording medium 153. Is read. This secondary information can have different contents from the information read in FIG. 13A because the recorded position is different.

  FIG. 13C shows an example of an optical pattern composed of brightness and darkness of diffracted light detected on the light receiving surface 155. FIG. 13C shows a light / dark pattern on the light receiving surface 155 of the diffracted light from the regions 11 to 13 of each identification medium detected in the readout of (A) and each detected in the readout of (B). The light and dark patterns on the light receiving surface 155 of the diffracted light from the areas 21 to 23 of the identification medium are simultaneously shown.

  Information is written on each recording medium by writing hologram information to each area of each recording medium indicated by reference numerals 11 to 13 and reference numerals 21 to 23 by the method shown in FIG. Here, an example in which information is read in two stages of FIGS. 13A and 13B has been described, but it is needless to say that information can be read in more stages.

FIG. 14 is a conceptual diagram illustrating an example of an information writing device. The information writing apparatus shown in FIG. 14 records hologram information on a recording medium 161 provided with a recording layer 161a. In this apparatus, the recording medium 161 is placed on the moving stage 162. The moving stage 162 can be moved in the direction of the arrow 163.

  This information writing device includes a laser irradiation device 164. The laser irradiation device 164 includes an optical system, and outputs a beam whose cross section extends in the depth direction in the figure. Although the wavelength of the laser beam is arbitrary, visible light is used here. Laser light output from the laser irradiation device 164 is divided into two orthogonal directions by a beam splitter 165a, one of which is reflected by a mirror 165b and applied to the recording medium 161 as reference light. The other beam divided by the beam splitter 165 a is reflected by the mirror 165 c and further passes through the spatial modulator 166 to become recording light, which is irradiated onto the recording medium 161. The spatial light modulator 166 is an optical shutter using a liquid crystal panel, and has a structure in which a plurality of pixels are arranged along the extending direction of the belt-shaped laser beam. The reference light and the recording light are in a positional relationship where the beams intersect at the central portion of the thickness of the recording layer 161a.

  Next, the control system will be described. This apparatus includes a write information generation apparatus 167. The write information generation device 167 reads the information recorded in the memory 168, generates a data signal based on the information to be written to the recording medium 161, and outputs it to the spatial light modulator driving device 169. Based on this data signal, the spatial light modulator driving device 169 controls the modulation action of the laser light in the spatial light modulator 166. At the same time, the writing information generating device 167 outputs a control signal to the stage driving device 170 based on the writing information. The stage driving device 170 controls the position of the stage 162 based on this control signal. According to this mechanism, the irradiation timing of the recording light modulated by the spatial modulator 166 and the timing for adjusting the position of the stage 162 are adjusted, and writing of information to the band-shaped area of the recording layer 161a is performed. Are sequentially performed while being scanned in a direction orthogonal to the horizontal direction (the horizontal direction in the figure).

  This information writing apparatus can be used, for example, for writing information to each recording medium to be read shown in FIG. 9 and writing information to each recording medium to be read shown in FIG. If the reference light and the recording light are irradiated while scanning the stage 162 with the state of the spatial light modulator 166 fixed, the same information writing form as in FIG. 7 can be obtained.

  Hereinafter, an example of writing of information to each recording medium on which reading shown in FIG. 9 is performed will be described. In this case, the following data is recorded in the memory 168 of the information writing apparatus in FIG. 14 as a premise. That is, as shown in FIG. 9, information to be written in the area 111a of the recording medium 111 (information 1) and recording so that the information read out in a state where the identification media 111 to 113 are overlapped becomes predetermined significant information. Information to be written in the area 112a of the medium 112 (information 2) and information to be written in the area 113a of the recording medium 113 (information 3) are recorded in the memory 168 in FIG.

  More specifically, information (information 1) is information to be written to the recording medium 111, and information on the writing position (area 111a) of (information 1) is associated with (information 1). Are recorded in the memory 168. Similarly, (information 2) is information to be written to the recording medium 112, and information on the writing position (region 112a) of (information 2) is associated with (information 2) in the memory. 108. Similarly, (information 3) is information to be written to the recording medium 113, and information regarding the writing position (region 113a) of (information 3) is associated with (information 3) in the memory. 108. These data can be provided via an external recording medium or an appropriate line.

  The procedure for writing information to each recording medium will be described below. First, an example of writing information to the recording medium 111 will be described. First, the recording medium 111 is placed on the moving stage 162. That is, the recording medium 111 of FIG. 9 is placed on the moving stage 162 instead of the recording medium 161 of FIG. Next, the stage 162 is moved and the position of the area is adjusted so that the reference light and the recording light strike the portion of the band-like area 111a of the recording layer 114 in FIG. Thereafter, laser light is output from the laser light irradiation device 164, and the region is irradiated with reference light and recording light. At this time, the spatial light modulator 166 is controlled so that light modulation based on information to be written in the area is performed. In this way, information to be written on the recording medium 111 is written in the area 111a of the recording medium 111 in FIG. 9 using the principle of hologram recording.

  Information is written to the recording medium 112 and the recording medium 113 by the same procedure. That is, information to be recorded on the recording medium 112 is written in the area 112 a of the recording medium 112, and information to be recorded on the recording medium 113 is written in the area 113 a of the recording medium 113.

  As shown in FIG. 9, three recording media 111 to 113 on which information has been written are overlapped, and in this state, the same reference light used for writing information is irradiated at the same angle as reproducible illumination light. As shown in FIGS. 9 and 10, the diffracted light from the medium is detected in a state where the positions are shifted and two-dimensionally arranged. Secondary information based on information recorded on each of the recording media 111 to 113 is obtained from the matrix pattern of the diffracted light (see, for example, the description related to FIG. 11).

  The information writing apparatus shown in FIG. 14 operates under the control of a control computer (not shown). An operation program for performing the above-described operation is recorded in the memory of the computer, and is read and the content is executed by the control computer. This operation program can also be provided from an externally connected recording medium or line.

Based on secondary information read from a plurality of stacked recording media, authenticity determination and authentication can be performed. For example, the case where the recording medium of the present invention is applied to an identification card (identification card) will be described. In this case, the identification card is constituted by the three recording media 111 to 113 shown in FIG. 9, and the bearer of the identification card piles them up in the order determined in the portion where the reproduction illumination light of the recognition device hits. At this time, if an identification medium in which predetermined authentication data is not recorded is used, data verification cannot be performed, resulting in an authentication error. Also, if the overlapping order is different, the obtained secondary information is different from that determined in advance, so that data verification cannot be performed, resulting in an authentication error.

  For example, as a hardware for performing this authentication, an improved version of the apparatus shown in FIG. 11 can be used. In this case, the game control device 133 of the device shown in FIG. 11 is used as an authentication determination device, and an authentication result notification device, a gate control device, and the like (not shown) may be controlled based on the result.

9 and 11 show examples in which recording media having a single recording layer are stacked and information is read in multiple layers. By utilizing this principle, a recording medium having a plurality of recording layers can be provided from the beginning, and information written in a plurality of layers can be read out based on the same principle as in FIGS.

  This example will be described below. FIG. 15 shows an example of a recording medium provided with multiple recording layers. In this example, the recording medium 171 includes three recording layers 171a, 171b, and 171c. The recording medium 171 has a structure in which three recording media shown in FIGS. 1 and 2 are stacked with a light-transmitting adhesive.

  Hereinafter, an example of how information is written to the recording medium 171 will be described. Here, an example of writing information to the recording medium 171 using an improved version of the information writing apparatus shown in FIG. 14 will be described. In this example, the information recording apparatus shown in FIG. 14 has a structure in which the moving stage 162 is movable up and down in addition to right and left.

  First, the recording medium 171 is placed on the moving stage 162. Next, the moving stage 162 is moved left and right (in the direction of the arrow 163) to determine the position on the plane where information is written. In this example, the position in the direction of the arrow 163 in FIG. 14 is determined so that information is written in the portion 31. Next, the moving stage 162 is moved up and down so that the recording layer 171a shown in FIG. 15 is positioned at the focal position of the reference light and the recording light. After that, information is written into the recording layer 171a by the procedure described in relation to the third embodiment.

  Next, the moving stage 162 is moved to the left and right, and the position of the stage 162 is adjusted so that information is written in the portion 32. Then, the height of the stage 162 is adjusted so that the recording layer 171b of FIG. 15 is positioned at the focal position of the reference light and the recording light, and the recording layer 171b is performed according to the procedure described in relation to the third embodiment. Write information to.

  Next, the moving stage 162 is moved to the left and right, and the position of the stage 162 is adjusted so that information is written in the reference numeral 23. Then, the height of the stage 162 is adjusted so that the recording layer 171c shown in FIG. 15 is positioned at the focal position of the reference light and the recording light, and the recording layer 171c is performed according to the procedure described in relation to the third embodiment. Write information to.

  In this way, information is written to the three recording layers. Reading of the written information is the same as that described with reference to FIG. 9, FIG. 11, or FIG. As a method for obtaining the recording medium 171, a method is employed in which recording medium pieces each having one recording layer are individually manufactured, information is individually written to them, and then they are stacked and integrated. You can also.

It is also possible to read the written information by irradiating the reproduction illumination light perpendicularly to the identification medium. In this case, when writing information, the reference light is irradiated from a direction perpendicular to the surface of the identification medium, and the recording light is irradiated from a different direction. At the time of reading, reproduction illumination light is irradiated from a direction perpendicular to the plurality of stacked recording media. At this time, the diffracted light (reproduced light) is output in a direction (predetermined direction) having a certain angle with respect to the reproduced illumination light. Since the diffracted light is output in the predetermined direction from different positions in the stacking direction of the recording media, it can be detected separately. That is, information can be read out based on the same principle as shown in FIG. 9, FIG. 11, FIG. 12, FIG.

  The present invention can be used for a medium for recording information and a technology related thereto.

It is a perspective view which shows the outline | summary of a recording medium. It is sectional drawing which shows the cross-section of a recording medium. It is a conceptual diagram which shows the principle which writes hologram information. It is a conceptual diagram which shows the principle which reads the written hologram information. It is a conceptual diagram which shows the function of a spatial light modulator. It is a conceptual diagram which shows the state which writes the hologram information on a recording medium. It is a conceptual diagram which shows the principle which reads the hologram information from a recording medium. It is a conceptual diagram which shows the principle which reads the hologram information from a recording medium. It is a conceptual diagram which shows the principle which reads the hologram information from the laminated recording medium. It is a conceptual diagram which shows the state of the diffracted light detected by a light-receiving surface. It is a conceptual diagram which shows an example of the information reader. It is a conceptual diagram which shows an example of the information reader. It is a conceptual diagram which shows the principle which reads the hologram information from the laminated recording medium. It is a conceptual diagram which shows an example of the apparatus which writes the hologram information to a recording medium. It is sectional drawing which shows the structure of another example of a recording medium.

  DESCRIPTION OF SYMBOLS 100 ... Recording medium, 101 ... Base material, 102 ... Recording layer, 103 ... Spatial light modulator, 111 ... Recording medium, 112 ... Recording medium, 113 ... Recording medium, 111a ... Hologram information is memorize | stored, and reproduction illumination light is applied The region where the diffracted light is generated, 112a... The region where the hologram information is stored and the reproduction illumination light is applied and the diffraction light is generated, 113a. The region where the hologram information is stored and the reproduction illumination light is applied and the diffraction light is generated.

Claims (3)

Method for reading hologram information recorded on the first recording medium and the second recording medium in a state where a first recording medium having a recording layer for recording hologram information and a second recording medium are overlapped Because
Irradiating reproduction illumination light from the oblique or perpendicular direction to the superimposed surface in a state where the first recording medium and the second recording medium are overlapped;
Detecting the first diffracted light from the first recording medium and the second diffracted light from the second recording medium that are generated by irradiation with the reproduction illumination light in a separated state ;
Obtaining secondary information on the order in which the first recording medium and the second recording medium are overlapped based on the first diffracted light and the second diffracted light. How to read information. An apparatus for reading out hologram information recorded on the first recording medium and the second recording medium in a state where the first recording medium provided with a recording layer for recording hologram information and the second recording medium are overlapped. Because
Reproduction illumination light irradiating means for irradiating reproduction illumination light on the superimposed surface in an oblique or vertical direction in a state where the first recording medium and the second recording medium are overlaid,
Reproduction light detection for detecting the first diffracted light from the first recording medium and the second diffracted light from the second recording medium generated by irradiation with the reproduction illumination light in a separated state Means,
An information reading device comprising: a determination unit that determines an order in which the first recording medium and the second recording medium are stacked based on the first diffracted light and the second diffracted light. apparatus. Processing for reading hologram information recorded on the first recording medium and the second recording medium in a state where the first recording medium and the second recording medium provided with a recording layer for recording hologram information are overlapped A program for executing
A reproduction illumination light irradiating step of irradiating reproduction illumination light on the superimposed surface obliquely or vertically from the first recording medium and the second recording medium; and
Reproduction light detection for detecting the first diffracted light from the first recording medium and the second diffracted light from the second recording medium generated by irradiation with the reproduction illumination light in a separated state Steps,
Causing the computer to execute secondary information related to the order in which the first recording medium and the second recording medium are stacked based on the first diffracted light and the second diffracted light. A program characterized by

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