KR20080002246A - Optical pickup apparatus for holographic digital data storage system - Google Patents

Abstract

An optical pickup apparatus for a holographic digital data storage system is provided to minimize the size of a pickup body by using an LCOS(Liquid Crystal On Silicon) as an optical modulator, adapting a compact camera element as a detecting element and aligning a Fourier transforming lens. An optical pickup apparatus for a holographic digital data storage system includes a pickup body(50), a first optical guide member(61), a reference light actuator(88), a plurality of transforming lenses(71,72,73,74), an objective lens(84), and a detecting element. The first optical guide member is configured onto one layer of the pickup body to divide a light from the optical source into a reference light and an information light to be sent to different layers. The reference light actuator is installed on a layer different from the layer on which the first guide member is configured in order to send the reference light to a record element. The transforming lenses are Furrier lenses, where a path between the first and second furrier lenses is parallel to a path between the third and fourth lenses. The optical modulator converts the information light into desired data. The objective lens projects information light onto a record medium. The detecting element is configured to detect the information light from the record medium.

Description

Optical pickup apparatus for holographic digital data storage system

1 is a block diagram showing the configuration of a typical hologram data storage system.

Figure 2 is a block diagram showing the configuration of a hologram data storage system according to the present invention.

Figure 3 is a perspective view showing the configuration of an optical pickup device according to the present invention.

4 is a perspective view showing the optical pickup device of the present invention shown in FIG. 3 upside down.

Explanation of symbols on the main parts of the drawings

50: pickup body 52: movement guide

54: substrate 60: light source

61: first light guide member 62: second light guide member

64: optical expander 66: optical splitter

68: optical modulator 70: first path changing member

71, 72, 73, 74: Conversion lens 76: Second path changing member

78: third path changing member 80: fourth path changing member

82: third light guide member 84: objective lens

86: fifth path changing member 88: reference light actuator

90: actuator body 91: movement guide

92: guide pin 94: rotating body

94 ': rotating shaft 96: light reflecting member

The present invention relates to a hologram data storage system, and more particularly to hologram data storage for transmitting light from a light source to a hologram recording device and reading light from the hologram element in a hologram storage system for recording and reading digital data. An optical pickup device of a system.

Conventional CD / DVD storage device is a two-dimensional storage method for storing information by condensing the light from the laser light source on the signal recording surface of the disk. In this case, the data storage capacity is increased by adjusting the pitch interval between tracks or increasing the number of recording layers. However, there is a physical limit to increasing data storage in this manner, and if the storage capacity is increased above a certain level, it is technically impossible to increase the storage capacity.

Therefore, the hologram storage method, which is a three-dimensional stereoscopic storage method, was introduced to overcome this problem. This allows data to be recorded inside the recording element by using light diffraction and interference effects, thereby securing tens to hundreds of times more storage capacity than CD / DVD.

A general configuration of such a hologram data storage system will be briefly described with reference to FIG. 1. According to this, the beam splitter 12 which separates the laser applied from the laser beam generator 10 into the reference light 30 and the information light 40 is provided. The reference light 30 applied through the beam splitter 12 is reflected by the first rotating reflector 14 in a desired direction. In addition, the information light 40 applied through the beam splitter 12 is reflected by a second rotation reflector 16 in a desired direction.

The information light 40 is reflected by the second rotating reflector 16 to carry data generated by the data generator 24. That is, data is loaded on the information light 40 by the spatial light modulator 18.

The data modulated by the spatial light modulator 18, that is, the information light 40, is recorded in the hologram recording element 22 by the objective lens 20. In this case, the reference light 30 reflected by the first rotation reflector 14 interferes with the information light 40 to generate hologram data, and the hologram data is stored in the hologram recording element 22.

On the other hand, the imaging section 26 picks up the light emitted from the hologram recording element 22 to read the hologram data.

However, the prior art having the configuration as described above has the following problems.

In other words, the hologram data storage system developed so far is large. Therefore, there is a problem that cannot be employed like a conventional optical disc drive in a personal computer or a notebook. Thus, holographic data storage systems have not been widely used so far despite their relatively large storage capacity and high speed.

An object of the present invention is to solve the problems of the prior art as described above, and to provide a miniaturized hologram data storage system.

Another object of the present invention is to provide an optical pickup apparatus of a hologram data storage system that can be employed in a configuration such as an optical disk drive.

According to a feature of the present invention for achieving the object as described above, the present invention is installed in any one layer of the pickup body, the pickup body is separated into a reference light and information light transmitted from a light source and transmitted to different layers. The first light guide member, a reference light actuator installed on a layer different from the first light guide member, and the first light guide member so as to transmit the reference light transmitted through the first light guide member to a recording device. An optical modulator for modulating on information light into desired data, a plurality of conversion lenses arranged so that at least some of the optical paths are arranged side by side on an optical path of a predetermined distance so as to maintain the quality of the information light passing through the optical modulator; And an objective lens for irradiating the information light emitted through the conversion lens to the recording element, and a detection element for detecting the information light from the recording element. .

The conversion lens is a first to fourth Fourier transform lens, and a path between the first and second Fourier transform lenses and a path between the third and fourth Fourier transform lenses are arranged side by side.

The information light emitted through the fourth Fourier transform lens is changed by the fourth path changing member in the same direction as the path changing direction between the first and second Fourier transform lenses and the third and fourth Fourier transform lenses. .

The reference light actuator may include an actuator body movably supported by guide pins installed side by side on the pickup body, a rotation body rotatably installed on the actuator body, and light installed on the rotation body and transmitting a reference light to a recording device. It is configured to include a reflective member.

The rotating body is rotated by a coil and a magnet installed at positions corresponding to each other of the actuator body and the rotating body.

A light expander is further provided to allow the light passing through the first light guide member to be irradiated to the entire area of the light modulator.

An optical splitter having an output direction different according to the incident direction of the information light is installed between the optical expander and the optical modulator to selectively transmit the information light toward the optical modulator, the conversion lens, and the detection element.

According to another feature of the invention, the present invention is the pickup body which is moved along the guide shaft, and the first light guide member is installed on any one layer of the pickup body to separate and transmit the reference light and information light transmitted from the light source; And a second light guide member for guiding the reference light passing through the first light guide member in a layer different from the layer in which the first light guide member is installed, and transmitting the reference light transmitted through the second light guide member to the recording device. A reference light actuator installed on the other layer, an optical modulator for modulating the information light passing through the first light guide member into desired data, and a sight of a predetermined distance to maintain the quality of the information light passing through the optical modulator. A plurality of conversion lenses arranged so that at least a part of the optical paths are arranged side by side on the furnace, an objective lens for irradiating the information light emitted through the conversion lenses to the recording element; And an optical separator for transmitting the information light transmitted from the first light guide member and the information light from the recording device by varying the output path according to the incident path, and a detection device for detecting the information light from the recording device. It is composed.

The conversion lens is a first to fourth Fourier transform lens, and a path between the first and second Fourier transform lenses and a path between the third and fourth Fourier transform lenses are arranged side by side.

The information light emitted through the fourth Fourier transform lens is changed by the fourth path changing member in the same direction as the path changing direction between the first and second Fourier transform lenses and the third and fourth Fourier transform lenses. .

A light expander is further provided to allow the light passing through the first light guide member to be irradiated to the entire area of the light modulator.

The optical modulator is Elcos (LCOS) is used.

According to another feature of the invention, the invention is installed in at least two layers of the pickup body moved by the drive source, the reference light and information light from the light source through the different layers to transfer the hologram data to the recording element In the optical pickup apparatus for recording and reproducing, a plurality of conversions are provided over a predetermined interval to maintain the quality of the information light in the process of passing the information light through the optical modulator to the objective lens for condensing the information light to the recording element. At least some of the optical paths formed by the lens are arranged to be parallel to each other.

The conversion lens is a first to fourth Fourier transform lens, and a path between the first and second Fourier transform lenses and a path between the third and fourth Fourier transform lenses are arranged side by side.

The information light emitted through the fourth Fourier transform lens is changed by the fourth path changing member in the same direction as the path changing direction between the first and second Fourier transform lenses and the third and fourth Fourier transform lenses. .

According to the optical pickup device of the hologram data storage system according to the present invention having such a configuration, the hologram data storage system can be miniaturized, so that it can be employed in mobile devices including personal computers or laptops, so that users can use a larger storage system. There is an advantage to this.

Hereinafter, exemplary embodiments of an optical pickup apparatus of a hologram data storage system according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram showing the configuration of the holographic data storage system according to the present invention, FIG. 3 is a perspective view showing the configuration of the optical pickup apparatus according to the present invention, and FIG. 4 is shown in FIG. A perspective view of the optical pickup device of the embodiment is shown upside down.

As shown in these figures, in the optical pickup device of the present invention, many parts are installed on the pickup body 50. The pickup body 50 is provided with movement guides 52 at both ends thereof, and is moved by driving of a driving source along a movement guide shaft installed side by side on an optical pickup base (not shown). For example, if hologram data is recorded on a disc on a disc, it is linearly reciprocated along the movement guide axis with the driving force of the drive source in the radial direction of the disc. Reference numeral 54 denotes an area where the substrate is installed.

The light source 60 is installed on the optical pickup base, for example, and generates light for recording or reproducing hologram data. The light source 60 generates light having a specific wavelength, and generally generates parallel light.

One side of the pickup body 50 is provided with a first light guide member 61. The first light guide member 61 is installed at a position facing the light source 60 so as to receive the light from the light source 60 without interference. The first light guide member 61 guides the reference light and the information light to be transferred through different paths, respectively. The layer on which the first light guide member 61 is installed is called a first layer of the pickup body 50 for convenience.

The second light guide member 62 is installed on a layer different from the first layer on which the first light guide member 61 is installed, that is, the second layer. The second light guide member 62 serves to guide the reference light transmitted from the first light guide member 61 to a desired position. For reference, the first layer and the second layer may be various combinations, such as the lower surface and the upper surface of the pickup body 50, the inner surface and the upper surface or the lower surface of the pickup body 50, as shown.

The light expander 64 is installed on the floor on which the first light guide member 61 is installed. The light expander 64 serves to enlarge the information light to the state of parallel light. The light expander 64 may be composed of, for example, two lenses, which enlarge the light but maintain the parallel light.

The optical separator 66 serves to transmit the information light that is transmitted through various paths. The optical splitter 66 may transmit the information light through various paths, for example, using a polarization state of the information light. In this embodiment, the information light emitted from the optical expander 64 passes through the optical splitter 66 and is transmitted to the optical modulator 68, which will be described below, and the information light emitted from the optical modulator 68 is The information light reflected by the first path changing member 70 to be described is transmitted to the detection element 99 to be described below.

The optical modulator 68 loads digital data to be recorded on the information light. As the optical modulator 68, a so-called spatial light modulator (SLM) may be used, or Elcos (Liquid crystal on silicon) may be used. However, it is preferable to use Elcos for miniaturizing the optical pickup device.

The first path changing member 70 is for transmitting the light that has passed through the optical modulator 68 and passes through the optical separator 66 to the desired path. The light whose path is changed by the first path changing member 70 passes through the first to fourth conversion lenses 71, 72, 73, and 74, which will be described below. As these conversion lenses 71, 72, 73 and 74, it is preferable to use a Fourier conversion lens (hereinafter referred to as a Fourier conversion lens).

The first to fourth Fourier transform lenses 71, 72, 73 and 74 form a '-' shaped path in the present invention. This is to minimize the width of one side of the pickup body 50 while maintaining a constant distance between the first and fourth Fourier transform lenses 71 and 74. That is, the paths between the first and second Fourier transform lenses 71 and 72 and the paths between the third and fourth Fourier transform lenses 73 and 74 are positioned side by side in one width direction of the pickup body 50. Minimizing the width of the pickup body (50). As in this embodiment, when the Fourier transform lenses 71, 72, 73 and 74 are arranged, the width in the direction of movement of the pickup body 50, that is, in the case where the disc on the disc is a hologram recording element, is the radial direction thereof. The width of is minimized.

Second and third path changing members 76 and 78 are disposed between the first and second Fourier transform lenses 71 and 72 and between the third and fourth Fourier transform lenses 73 and 74, respectively. Each of the paths of information light is changed by 90 degrees.

The fourth path changing member 80 causes the path of the information light emitted from the fourth Fourier transform lens 74 to be vertically changed again. In particular, the fourth path changing member 80 is formed of the light formed by the Fourier transform lenses 71, 72, 73, and 74. It is arranged to keep the path and draw a rough quadrilateral.

The third light guide member 82 serves to transmit the information light passing through the fourth path changing member 80 to another layer of the pickup body 50. For reference, prisms may be used as the light guide members 61, 62, and 80.

The objective lens 84 serves to irradiate light to the hologram recording element. The objective lens 84 is exposed and installed to be visible from the upper portion of the pickup body 50. Of course, the objective lens 84 is preferably installed on a bobbin (not shown) of a separate actuator (not shown). This is to ensure that the light from the objective lens 84 is accurately tracked and focused on the hologram recording element.

Meanwhile, a fifth path changing member 86 is installed on the second layer of the pickup body 50 to guide the reference light guided to the second light guide member 62. The fifth path changing member 86 changes the path of the reference light by 90 degrees.

The reference light actuator 88 should be installed on the pickup body 50 such that it can be seen from above the pickup body 50 like the objective lens 84. The reference light actuator 88 rotates a portion while linearly reciprocating in one direction to enable angle multiplexing of the information light.

The reference light actuator 88 is provided with an actuator body 90. Movement guides 91 are provided at both ends of the actuator body 90, and the movement guides 91 are movably supported by guide pins 92 installed in parallel with the pickup body 50. Thus, the actuator body 90 is moved along the guide pin 92. Power for the movement of the actuator body 90 may be provided using a separate sled motor (not shown).

The actuator body 90 is provided with a rotatable body 94 to be rotatable about a rotating shaft 94 '. The rotating body 94 is provided with a light reflection member 96 serves to irradiate the hologram recording element with the reference light transmitted through the fifth path changing member 86.

A coil 97 is installed on the rotating body 94 to rotate the rotating body 94, and a magnet 98 is installed on the actuator body 90 so as to face the coil 97. When power is applied to the coil 97, the rotating body 94 is rotated by interacting with the magnet 98. For reference, it is preferable to use a voice coil as the coil 97.

On the other hand, the first layer is provided with a detection element 99 for reading the information light from the hologram recording element. An image pickup device CCD may be used as the detection device 99. In particular, in order to downsize the pickup body 50, it is preferable to use a small image pickup device used in a mobile phone.

Hereinafter, the operation of the optical pickup device of the hologram data storage system according to the present invention having the configuration as described above will be described in detail.

In the present invention, the pickup body 50 is movably supported by the movement guide 52 on the guide shaft and is linearly reciprocated by the driving force of the driving source. For reference, the driving source for driving the pickup body 50 is separate from the driving source for driving the reference light actuator 88. When the hologram recording element is a disc, the pickup body 50 is linearly reciprocated in the radial direction of the disc.

As described above, the pickup body 50 is moved to perform recording and reproducing. The reference light and the information light emitted from the light source 60 are first transmitted to the first light guide member 61. The reference light transmitted to the first light guide member 61 is transmitted to the second light guide member 62 on the other layer, and by the second light guide member 62 and the fifth path changing member 86. The reference light actuator 88 is delivered.

The reference light transmitted to the reference light actuator 88 is a linear movement of the actuator body 90 along the guide pin 92 and the rotating body 94 rotates about the rotation axis 94 'of the hologram recording element. It is transmitted by the light reflection member 96 to a specific position. In this case, the actuator body 90 is linearly reciprocated by a separate driving source, and the rotary body 94 is rotated by the coil 97 and the magnet 98.

Meanwhile, the information light transmitted to the first light guide member 61 is enlarged while maintaining the state of parallel light by the light expander 64. The expansion of the information light in the light expander 64 is to cover the entire area of the light modulator 68. Therefore, if the light emitted from the light source 60 can cover the entire area of the optical modulator 68, it is not necessary to use the light magnifier 64.

The information light exiting the optical expander 64 is transmitted to the optical modulator 68 via the optical splitter 66. The information light carrying data in the optical modulator 68 is transmitted to the optical separator 66 again, and is transmitted from the optical separator 66 to the first path changing member 70.

The information light transmitted to the first path changing member 70 sequentially passes through the Fourier transform lenses 71, 72, 73, and 74 to maintain its quality level. For reference, the paths of the Fourier transform lenses 71, 72, 73, and 74 are changed vertically two times in the clockwise direction with reference to the drawings. By arranging the Fourier transform lenses 71, 72, 73 and 74, the size of the pickup body 50 can be relatively reduced.

Light passing through the Fourier transform lenses 71, 72, 73 and 74 passes through the Fourier transform lenses 71, 72, 73 and 74 by the fourth path changing member 80 in the changed optical path direction. Once again, the light path is changed and transmitted to the third light guide member 82. The third light guide member 82 sends the information light to the objective lens 84 in another layer on the pickup body 50.

The information light transmitted to the objective lens 84 is focused on the hologram recording element by the objective lens 84, and data recording is performed while the reference light and the information light interfere with each other.

In addition, the data recorded in the hologram recording device transmits the reference light and the information light reflected from the recording device through the reverse path to the optical separator 66 through the objective lens 84, and the optical separator 66. Is transmitted to and detected by the detection element (99).

The rights of the present invention are not limited to the embodiments described above, but are defined by the claims, and various changes and modifications can be made by those skilled in the art within the scope of the claims. It is self-evident.

In the optical pickup apparatus of the hologram data storage system according to the present invention as described in detail above, the following effects can be obtained.

According to the present invention, an optical pickup apparatus capable of storing hologram data is provided by dividing components except a light source into two layers on a pickup body which can be linearly reciprocated by a driving force of a driving source. Therefore, applying this to the hologram data storage system has an effect that can be miniaturized the size of the hologram data storage system.

In particular, in the present invention, Elcos (LCOS) is used as an optical modulator for information light modulation, a miniaturized image pickup device is employed as a detection element, and the size of the pickup body is minimized by appropriately disposing a Fourier transform lens. The hologram data storage system can be applied to the same configuration as an optical disk drive, and thus a large capacity can be relatively stored in a mobile device including a personal computer or a notebook.

In the present invention, the reference light actuator for irradiating the reference light to the hologram recording element can be linearly reciprocated, and the light reflecting member is installed on a rotating body rotatable with respect to the reference light actuator to enable angle multiplexing. It also has the effect of maximizing performance.

Claims (16)

Pickup body, A first light guide member installed at any one layer of the pickup body and separated into a reference light and an information light transmitted from a light source and transmitted to different layers; A reference light actuator installed on a layer different from the first light guide member so as to transmit the reference light transmitted through the first light guide member to a recording device; An optical modulator for modulating the information light passing through the first light guide member into desired data; A plurality of conversion lenses disposed so that at least some of the optical paths are side by side on the optical paths of a predetermined distance so as to maintain the quality of the information light which has passed through the optical modulator; An objective lens for irradiating the information light emitted through the conversion lens to a recording element; And a detection element for detecting the information light from the recording element. The method of claim 1, wherein the conversion lens is a first to fourth Fourier transform lens, and the path between the first and second Fourier transform lenses and the path between the third and fourth Fourier transform lenses are arranged side by side. Optical pickup device of the holographic data storage system. 3. The fourth path changing member of claim 2, wherein the information light passing through the fourth Fourier transform lens is in the same direction as the path changing direction between the first and second Fourier transform lenses and the third and fourth Fourier transform lenses. The optical pickup device of the hologram data storage system, characterized in that the path is changed by. The method of claim 3, wherein the reference light actuator, An actuator body movably supported by guide pins installed side by side on the pickup body; A rotating body rotatably installed on the actuator body; The optical pickup device of the hologram data storage system, characterized in that it comprises a light reflection member installed on the rotating body for transmitting a reference light to the recording element. The optical pickup apparatus of claim 4, wherein the rotating body is rotated by a coil and a magnet installed at positions corresponding to each other of the actuator body and the rotating body. The optical pickup apparatus of any one of claims 1 to 5, wherein the optical modulator uses Elcos (LCOS). 7. The optical pickup apparatus of claim 6, further comprising an optical magnifier for radiating the light passing through the first light guide member to the entire area of the optical modulator. [8] The method of claim 7, wherein an optical splitter having a different output direction according to the incident direction of the information light is installed between the optical magnifier and the optical modulator to selectively transmit the information light toward the optical modulator, the conversion lens, and the detection element. Optical pickup device of hologram data storage system. A pickup body moved along the guide shaft, A first light guide member installed at any one layer of the pickup body to separate and transmit the reference light and the information light transmitted from the light source; A second light guide member for guiding the reference light passing through the first light guide member on a different layer from the layer on which the first light guide member is installed; A reference light actuator installed on the other layer so as to transmit the reference light transmitted through the second light guide member to a recording device; An optical modulator for modulating the information light passing through the first light guide member into desired data; A plurality of conversion lenses disposed so that at least some of the optical paths are side by side on the optical paths of a predetermined distance so as to maintain the quality of the information light which has passed through the optical modulator; An objective lens for irradiating the information light emitted through the conversion lens to a recording element; An optical splitter which transmits the information light transmitted from the first light guide member and the information light from the recording element by varying the exit path according to the incident path; And a detection element for detecting the information light from the recording element. 10. The method of claim 9, wherein the conversion lens is a first to fourth Fourier transform lens, the path between the first and second Fourier transform lens and the path between the third and fourth Fourier transform lens is arranged in parallel with each other. Optical pickup device of the holographic data storage system. 12. The fourth path changing member of claim 10, wherein the information light passing through the fourth Fourier transform lens is in the same direction as the path changing direction between the first and second Fourier transform lenses and the third and fourth Fourier transform lenses. The optical pickup device of the hologram data storage system, characterized in that the path is changed by. 10. The optical pickup apparatus of claim 9, further comprising an optical magnifier for radiating the light passing through the first light guide member to the entire area of the optical modulator. The optical pickup apparatus of any one of claims 9 to 12, wherein the optical modulator uses Elcos (LCOS). An optical pickup apparatus, in which components are installed in at least two layers of a pickup body moved by a driving source to transfer reference light and information light from a light source through different layers to record and reproduce hologram data in a recording device. At least a part of the optical path formed by the conversion lens, which is installed in a plurality over a predetermined interval, in order to maintain the quality of the information light while the information light passes through the optical modulator and is transmitted to the objective lens for collecting the information light to the recording device. Optical pickup device of the holographic data storage system characterized in that arranged side by side with each other. The method of claim 14, wherein the conversion lens is a first to fourth Fourier transform lens, wherein a path between the first and second Fourier transform lenses and a path between the third and fourth Fourier transform lenses are arranged side by side. Optical pickup device of the holographic data storage system. 16. The fourth path changing member of claim 15, wherein the information light passing through the fourth Fourier transform lens is in the same direction as the path changing direction between the first and second Fourier transform lenses and the third and fourth Fourier transform lenses. The optical pickup device of the hologram data storage system, characterized in that the path is changed by.

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