JP2006162661A - Hologram device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hologram device that can reproduce holograms recorded in a recording medium at high density, using a simple structure. <P>SOLUTION: The hologram device is equipped with a light-emitting section 1 to allow reference light 11 to enter each hologram 20 in a recording medium 2, where a plurality of holograms 20 are formed by interference between object light and reference light 11, and a light-receiving section 3 for receiving exiting light 22 from the hologram 20, where the light-emitting section 1 comprises a plurality of light-emitting elements 10, 10 each emitting reference light 11 and arrayed adjoining each other in a single line, and each light-emitting element 10 emits light at a different wavelength from those of adjoining light-emitting elements 10. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hologram apparatus that reads information recorded on a recording medium as a hologram, and more particularly to a hologram apparatus provided with a plurality of light emitting units that emit reference light.

  2. Description of the Related Art Conventionally, as a storage device used for a computer or the like, a device that performs two-dimensional writing and reading of information on a recording medium by magnetism or light is widely used. A hard disk or the like is known as a magnetic storage device, and a CD or DVD is known as a light storage device. These storage devices have so far made remarkable progress in terms of recording density in order to meet the demand for larger capacity. As a means for further increasing the capacity, development of a storage device using the principle of holograms is in progress.

The hologram device reads and reproduces information recorded as a hologram on a recording medium in units of pages. On the recording medium, encoded page unit information is written as a pattern such as a change in refractive index. This pattern is a hologram formed by the interference between the object beam and the reference beam in the recording apparatus. In order to read information from the recording medium, only the reference beam is incident on the recording medium and diffracted by the pattern of the hologram. The written information can be reproduced by receiving light by a photoelectric conversion element such as a CMOS. Such a hologram apparatus is described in Patent Document 1, for example.
JP 2003-43904 A

  However, in the conventional hologram device, when the hologram is formed on the recording medium at a high density, the reference light from the light emitting part is incident on the adjacent hologram, so that the light emitted from the hologram overlaps at the light receiving part, Cannot read. For this reason, in order to read information from a desired hologram, each hologram is arranged at a certain distance, or a pinhole filter is provided between the recording medium and the light receiving unit, and only the emitted light from the desired hologram is received. Must be extracted.

  Accordingly, in the former case, the density of the recording medium cannot be increased, and in the latter case, a pinhole filter must be used, which hinders downsizing of the apparatus.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a hologram apparatus capable of reproducing a hologram recorded on a recording medium at a high density with a simple configuration.

In order to solve the above-described problem, a hologram apparatus according to the present invention includes a light emitting unit that causes reference light to enter each hologram, with respect to a recording medium on which a plurality of holograms are formed by interference between object light and reference light. In a hologram device having a light receiving portion for receiving light emitted from a hologram,
Each of the light emitting units includes a plurality of light emitting elements that emit reference light, which are arranged close to each other, and each light emitting element emits light having a wavelength different from that of the adjacent light emitting elements.

In addition, the hologram apparatus according to the present invention includes a light emitting unit that causes the reference light to be incident on each of the holograms on a recording medium on which a plurality of holograms are formed by interference between the object light and the reference light, and light emitted from the hologram. In a hologram device having a light receiving unit for receiving light,
Each of the light emitting units includes a plurality of light emitting elements that emit reference light, which are arranged close to each other, and each light emitting element emits light having an emission angle different from that of the adjacent light emitting elements. .

  Further, the hologram apparatus according to the present invention is characterized in that the recording medium is formed with a plurality of hologram groups each including a plurality of holograms corresponding to reference light emitted from each light emitting element of the light emitting unit. ing.

  Furthermore, the hologram apparatus according to the present invention is characterized in that each hologram of the hologram group is formed by causing the object light to enter from the direction of the light receiving unit.

  The hologram device according to the present invention is characterized in that the light emitting element of the light emitting unit is a surface emitting laser.

  According to the hologram apparatus of the present invention, the light emitting unit includes a plurality of light emitting elements that emit reference light, which are arranged close to each other, and each light emitting element emits light having a wavelength or emission angle different from that of the adjacent light emitting element. By emitting light, even if the hologram is arranged close to or overlapping with the adjacent hologram, it is possible to read out only the hologram corresponding to the wavelength or incident angle of the reference light from the light emitting element. Holograms can be formed with high density. Moreover, since the pinhole filter used in the conventional apparatus is unnecessary, the apparatus can be made more compact than the conventional apparatus.

  According to the hologram apparatus of the present invention, the recording medium is formed with a plurality of hologram groups each including a plurality of holograms corresponding to the reference light emitted from each light emitting element of the light emitting unit. Since a plurality of hologram groups formed in close proximity to each other are formed, a plurality of holograms can be read out by a single alignment.

  Furthermore, according to the hologram apparatus of the present invention, each hologram of the hologram group is formed by causing the object light to enter from the direction of the light receiving unit, so that the light emitted from the hologram corresponding to the object light is the same by the light receiving unit. Since the light can be received at the position, the hologram can be easily read out only by fixing the light emitting part and the light receiving part and switching each light emitting element.

  Furthermore, according to the hologram apparatus according to the present invention, the light emitting element of the light emitting unit is a surface emitting laser, so that the light emitting unit having a plurality of light emitting elements can be easily manufactured in one process.

  Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing the configuration of the hologram device in the present embodiment, and FIG. 2 is a front view of FIG. As shown in each of these drawings, the hologram apparatus in this embodiment mainly includes a light emitting unit 1 that generates reference light 11, a recording medium 2 that receives light from the light emitting unit 1 as incident light, and an output from the recording medium 2. The light receiving unit 3 is configured to receive the incident light 22. The light receiving unit 3 is composed of a CCD or a CMOS sensor.

 The light emitting unit 1 includes a plurality of light emitting elements 10 and emits reference light 11 respectively. The light emitting elements 10 are arranged close to each other and emit light having a wavelength different from that of the adjacent light emitting elements 10. Further, the light emitting unit 1 includes a lens 12 and uses the reference light 11 emitted from each light emitting element 10 as parallel light. Here, a surface emitting element such as a surface emitting laser is used as the light emitting element 10. FIG. 3 is a graph showing the wavelength of the reference light from each light emitting element 10.

  The light emitting unit 1 in the present embodiment is configured by arranging a plurality of light emitting elements 10 close to each other. And each light emitting element 10 is provided from the light emitting element 10a to the light emitting element 10g in the arrangement order, as shown in FIG. As shown in FIG. 3, the wavelength of the light emitted from each light emitting element 10 is from 530 nm to 538 nm. Then, the wavelength of light gradually increases from the light emitting element 10a, returns to 530 nm again at the light emitting element 10f, and the wavelength of light increases again at the light emitting element 10g. Thus, the wavelength of the light emitted from each light emitting element 10 is different from the wavelength of the light from the adjacent light emitting element 10.

  The recording medium 2 is made of a photorefractive material or a photopolymer material, and information can be written by forming interference fringes between the encoded object light having page unit information and the reference light 11 as a hologram 20. Is. Reading of information from the recording medium 2 is performed by causing only the reference light 11 to enter the recording medium 2 and diffracting it with the pattern of the hologram 20.

  Here, when the reference light 11 is incident on the recording medium 2, the relationship between the wavelength λ of the reference light 11 for diffracting in the hologram 20 formed on the recording medium 2 and the incident angle θ is nλ = 2d sin θ (n Is a positive integer and d is the spacing of the lattice planes). Therefore, when the wavelength λ and the incident angle θ of the reference light 11 incident on the hologram 20 are the same as those at the time of forming the hologram 20, the reference light 11 is diffracted in the hologram 20, and the wavelength λ of the reference light 11 is When different from the formation time, or when the incident angle θ of the reference light 11 is different from the formation time, the reference light 11 is not diffracted in the hologram 20.

  That is, the hologram 20 emits light by the incidence of the reference light 11 used to form the hologram 20, and the information recorded on the recording medium 2 by receiving the emitted light 22 from the hologram 20 by the light receiving unit 3. Can be read out.

  The recording medium 2 in the present embodiment may be in the form of a disk and may be preliminarily arranged in the hologram apparatus, or may be inserted into a slot type. The shape of the recording medium 2 is not limited to this embodiment, and may be a card shape or other shapes.

  Further, as shown in FIG. 1, it is assumed that a hologram 20 is formed on the recording medium 2 in advance, and a plurality of holograms 20 and 20 are arranged close to each other in a line in the radial direction to form a hologram group 21. Here, each hologram 20 constituting the hologram group 21 is formed so as to correspond to the reference light 11 emitted from each light emitting element 10 of the light emitting unit 1. That is, as shown in FIG. 3, each hologram 20 constituting the hologram group 21 is formed so as to have a one-to-one correspondence with each light emitting element 10 of the light emitting unit 1.

  In addition, as shown in FIG. 2, the emitted light 22 from each hologram 20 is received by the light receiving unit 3. The hologram 20 formed on the recording medium 2 emits light corresponding to the object light used for formation when the reference light 11 is incident. Therefore, when each hologram 20 is formed by causing object light to enter the recording medium 2 from the direction of the light receiving unit 3, the light emitted from each hologram 20 by the incidence of the reference light 11 is emitted in the direction of the light receiving unit 3. Will do. That is, the emitted light 22 from each hologram 20 is emitted toward the light receiving unit 3 and received at the same position of the light receiving unit 3.

  Next, reading of information recorded on the recording medium 2 in the present embodiment will be described. Information recorded on the recording medium 2 is read out by causing light emitted from each light emitting element 10 included in the light emitting unit 1 to enter the hologram 20 and receiving light emitted from the hologram 20 by the light receiving unit 3. Is called. Here, since the light receiving unit 3 can reproduce only one type of information, the light emitting elements 10 of the light emitting unit 1 do not emit light simultaneously but sequentially emit light.

  First, as shown in FIG. 2, the reference light 11 is emitted from the light emitting element 10a, and the reference light 11 enters the corresponding hologram 20a. When the reference light 11 enters the hologram 20a, light is emitted from the hologram 20a, and the information of the hologram 20a can be read by receiving the emitted light 22 by the light receiving unit 3. Next, the reference light 11 is emitted from the light emitting element 10b and is incident on the corresponding hologram 20b. Information on the hologram 20b can be read out by the incidence of the reference light 11 on the hologram 20b as in the case of the hologram 20a. By repeating the same operation, the information of each hologram 20 constituting the hologram group 21 can be read out by only one alignment.

  Moreover, since each light emitting element 10 can be arrange | positioned at a very small space | interval, according to this arrangement | positioning, each hologram 20 in the hologram group 21 is arrange | positioned so that it may mutually overlap with the adjacent hologram 20 mutually. And the recording density of the recording medium 2 can be improved.

  Here, reading of information when each hologram 20 in the hologram group 21 is arranged so as to partially overlap the adjacent hologram 20 will be described. FIG. 4 is a diagram showing a case where the holograms 20b overlapping with the adjacent holograms 20a and 20c are read out.

  Each hologram 20 in the hologram group 21 is formed by the reference light 11 emitted from the corresponding light emitting element 10. Each light emitting element 10 emits light having a wavelength different from that of the adjacent light emitting element 10.

  Since the central hologram 20b partially overlaps with the adjacent left and right holograms 20a and 20c, the reference light 11b emitted from the central light emitting element 10b enters the corresponding central hologram 20b, and The left hologram 20a also enters the overlapping portion 23a with the central hologram 20b and the right hologram 20c also enters the overlapping portion 23c with the central hologram 20b. Since the central hologram 20b is formed by the reference light 11b from the corresponding central light emitting element 10b, the incident reference light 11b satisfies the above-described diffraction conditions, and the emitted light 22b is emitted from the central hologram 10b. appear.

  However, even if the reference light 11b from the central light emitting element 10b is incident on the left and right holograms 20a and 20c, the reference light 11a and 11c used for the formation have different light wavelengths. The light is not emitted from the left and right holograms 20a and 20c. Thereby, only the information of the central hologram 20b can be read.

  That is, only the hologram 20 corresponding to the wavelength of the reference light 11 emitted from each light emitting element 10 can be read out even if each hologram 20 in the hologram group 21 is arranged so as to overlap with the adjacent hologram 20. Therefore, the hologram 20 can be formed on the recording medium 2 with high density.

  In addition, the hologram device according to the present embodiment does not require a pinhole filter provided for separating the emitted light 22 from the hologram 20 in the conventional hologram device, so that the device can be made more compact than the conventional device. it can.

  A plurality of hologram groups 21 including a plurality of holograms 20 are formed on the recording medium 2. Therefore, in order to reproduce each hologram 20 of another hologram group 21, the recording medium 2 is moved so as to switch the hologram group 21. In order to move the recording medium 2, the central portion is connected to a motor (not shown) and rotated in the circumferential direction. When the recording medium 2 is card-shaped, a slider that moves in the plane direction is provided and moved. However, the switching method of the hologram group 21 is not limited to this embodiment, and the light emitting unit 1 may be moved while the recording medium 2 is fixed.

  Next, a second embodiment will be described. As in the first embodiment, the hologram apparatus according to the present embodiment includes a light emitting unit 1 that generates reference light 11, a recording medium 2 that receives light from the light emitting unit 1 as incident light, and light 22 emitted from the recording medium 2. And a light receiving portion 3 for receiving light. In addition, unlike the first embodiment, each light emitting element 10 included in the light emitting unit 1 emits light having the same wavelength, and is disposed so as to emit light having an emission angle different from that of the adjacent light emitting element. The FIG. 5 shows a front view of the hologram apparatus in the present embodiment.

  As shown in FIG. 5, the light emitting elements 10 in the present embodiment are arranged close to each other in a row and are arranged so as to emit light having emission angles different from those of the adjacent light emitting elements 10. FIG. 6 is a graph showing the emission angle θ of the reference light 11 from each light emitting element 10.

  As shown in FIG. 6, the light emitting elements 10a and 10c are arranged in a state where the light emitting elements 10b and 10c are inclined by 0.5 ° inward with respect to the light emitting element 10b. By arranging the other light emitting elements 10 in the same manner, each light emitting element 10 emits light having an emission angle different from that of the adjacent light emitting elements 10. Here, since each light emitting element 10 can be arranged at a minute interval as in the first embodiment, each hologram 20 in the hologram group 21 is partially shared with the adjacent hologram 20 corresponding to this arrangement. Can be arranged to overlap.

  Here, reading of information when the holograms 20 constituting the hologram group 21 are arranged so as to partially overlap each other will be described. FIG. 7 is a view showing a case where the holograms 20b overlapping with the adjacent holograms 20a and 20c are read out.

  As shown in FIG. 7, since the central hologram 20b partially overlaps with the adjacent left and right holograms 20a and 20c, the reference light 11b emitted from the central light emitting element 10b is the corresponding central hologram. In addition to being incident on 20b, the left hologram 20a is also incident on the overlapping portion 23a with the central hologram 20b and the right hologram 20c is also incident on the overlapping portion 23c with the central hologram 20b. Since the central hologram 20b is formed by the reference light 11b from the corresponding central light emitting element 10b, the incident reference light 11b satisfies the above-described diffraction conditions, and emitted light 22b is generated from the central hologram 10b. To do.

  However, even if the reference light 11b from the central light emitting element 10b is incident on the left and right holograms 20a and 20c, the reference light 11a and 11c used for formation differs from the incident angle with respect to the holograms 20a and 20c. Thus, no light is emitted from the left and right holograms 20a and 20c. Thereby, only the information of the central hologram 20b can be read.

  That is, even if each hologram 20 in the hologram group 21 is arranged so as to overlap with the adjacent hologram 20, the hologram 20 corresponding to the incident angle of the reference light 11 emitted from each light emitting element 10 with respect to the recording medium 2. Since only the data can be read out, the same effect as in the first embodiment can be obtained.

  Although the embodiment of the present invention has been described above, the application of the present invention is not limited to this embodiment, and can be variously applied within the scope of the technical idea. For example, the number of light emitting elements 10 constituting the light emitting unit 1 is not limited to the present embodiment, and may be more or less.

  Further, the setting of the wavelength difference or the emission angle difference between the adjacent light emitting elements 10 is not limited to the present embodiment as long as each hologram 20 in the hologram group 21 can be separated and reproduced.

  In the present embodiment, the hologram 20 formed on the recording medium 2 is a reflection hologram 20. However, the application of the present invention is not limited to this embodiment, and the light emitting unit 1 and the light receiving unit 3 are connected to the recording medium 2. It can also be applied to the transmission type hologram 20 by being arranged opposite to each other.

It is a perspective view which shows the structure of the hologram apparatus in this embodiment. It is a front view of FIG. It is the table | surface shown about the wavelength of the light light-emitted from each light emitting element in this embodiment. It is the figure which showed the case where the center hologram is read among the holograms in the hologram group formed in the recording medium in this embodiment. It is a front view of the hologram apparatus in 2nd Embodiment. It is the table | surface shown about the emission angle of the light light-emitted from each light emitting element in 2nd Embodiment. It is the figure which showed the case where the center hologram is read among the holograms in the hologram group formed in the recording medium in 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light emitting part 2 Recording medium 3 Light receiving part 10 Light emitting element 11 Reference light 20 Hologram 21 Hologram group 22 Output light 23 Overlapping part

Claims (5)

Hologram apparatus having a light emitting unit for making reference light incident on each hologram and a light receiving unit for receiving light emitted from the hologram with respect to a recording medium on which a plurality of holograms are formed by interference between object light and reference light In
The light emitting unit includes a plurality of light emitting elements that emit reference light, which are arranged close to each other in a row, and each of the light emitting elements emits light having a wavelength different from that of the adjacent light emitting elements. Hologram apparatus having a light emitting unit for making reference light incident on each hologram and a light receiving unit for receiving light emitted from the hologram with respect to a recording medium on which a plurality of holograms are formed by interference between object light and reference light In
The light emitting unit includes a plurality of light emitting elements that emit reference light, which are arranged close to each other in a row, and each of the light emitting elements emits light having an emission angle different from that of an adjacent light emitting element.   3. The hologram apparatus according to claim 1, wherein the recording medium is formed with a plurality of hologram groups each including a plurality of holograms respectively corresponding to reference light emitted from each light emitting element of the light emitting unit.   4. The hologram apparatus according to claim 1, wherein each hologram of the hologram group is formed by causing the object light to enter from a direction of the light receiving unit. 5. The hologram apparatus according to claim 1, wherein the light emitting element of the light emitting unit is a surface emitting laser.

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