KR100657672B1 - Apparatus and method for scanning a angle on the holographic rom system - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning device of a holographic ROM system, in particular, a light source for generating laser light, a data area in which data is superimposed by angular multiplexing, and a mark every time data is superimposed in the data area. An optical disk comprising an information area to be superimposed and recorded, a first polarization splitter which transmits a reference light for reproduction of the laser light and reflects the servo light, and is provided at the front end of the optical disk and reflects the servo light at a predetermined angle to the optical disk. In addition, it reflects the servo light incident and reflected on the optical disk, reflects the reproduction reference light at a predetermined incidence angle and provides the optical disk to the optical disk, and reflects the reproduction reference light transmitted by the first polarization separator to the double-sided mirror. It is installed between the provided reflecting mirror, the double-sided mirror and the reflecting mirror, and provides a reference light for reproduction. The refracting element that provides the reproduction reference light reflected by the reflection mirror to the double-sided mirror, and the refraction element and the double-sided mirror are driven to change the refractive index of the reproduction reference light and the reflection angle of the double-sided mirror to enter the optical disk. It provides a drive system for controlling the position, the servo light reflected by the first polarization splitter to one surface of the double-sided mirror, the servo system to detect the servo light reflected from one surface of the double-sided mirror and output as an electrical signal, and through the double-sided mirror Reproducing means for detecting the regenerated light reproduced from the optical disk by the reproducing reference light to be converted into an electrical signal, and a control unit for storing the electrical signal value output from the servo system in the memory when the electrical signal is output from the reproducing means; Include.

Description

Each scanning device and method of holographic ROM system {APPARATUS AND METHOD FOR SCANNING A ANGLE ON THE HOLOGRAPHIC ROM SYSTEM}

1 is a block diagram showing a playback apparatus of a holographic ROM system according to the prior art;

2 is a block diagram showing a holographic ROM system with each scan function according to the present invention;

3 is a view showing the structure of an optical disk used in the present invention;

4 is a view for explaining the operation of the refractive element according to the present invention,

5 is a view showing the structure of a light sensing unit applied to the present invention.

<Description of the code | symbol about the principal part of drawing>

100: optical disk 110: light source

120: first polarization separator 130: refractive element

132: double-sided mirror 134: reflective mirror

140: drive system 150: servo system

160: control unit 170: memory

180: first light detecting unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a holographic digital data storage system (HDDS). In particular, the recording angle information of angular multiplexing is recorded at a specific position of a holographic disc, and then the angle of the reproduction reference light incident upon reproduction is changed. A scanning apparatus and method of a holographic ROM system capable of performing a servo control by retrieving a multiplexed recording angle.

Currently, technologies for storing holographic digital data are being actively researched in various fields, for example, thanks to remarkable developments such as semiconductor lasers, charge coupled devices (CCDs), and liquid crystal displays (LCDs). As a result, fingerprint recognition systems for storing and reproducing fingerprints have been put to practical use, and are being expanded to various fields that can apply the advantages of large storage capacity and ultra-fast data transfer speed. Among them, a holographic digital data system storing a large amount of data is a storage medium, for example, optical refraction, in which an interference fringe generated when the signal light from a target object and a reference light are interfered with each other is sensitive to the amplitude of the interference fringe. By recording to a storage medium such as a photorefractive crystal, it is possible to display a three-dimensional image of an object and to superimpose hundreds to thousands of hologram data composed of bit data of binary data Can be stored.

1 is a block diagram showing a playback apparatus of a holographic ROM system according to the prior art.

Referring to FIG. 1, a reproducing apparatus of a conventional holographic ROM system includes a light source 10 for generating laser light, which is a reproducing reference light for reproducing hologram data, and an optical disc on which hologram data consisting of bit data is recorded in angular superposition ( 16) a mirror 12 for reflecting the reproduction reference light generated by the light source 10 at a predetermined incident angle and reflecting the light onto the optical disk 16, and a reproduction reference incident on the optical disk 16 by driving the mirror 12; An actuator 14 for controlling the angle of incidence of light, and a light detector 18 for detecting the reproduced light reproduced from the optical disc 16 by the reference light for reproduction and converting the converted light into an electrical signal. In this case, the light detector 18 detects data in units of bits and converts the data into an electrical signal. An example thereof may include a photo diode (PD).

The reproducing apparatus of the holographic ROM system configured as described above reproduces the data recorded on the optical disc 16 by providing the reference light for reproduction to the optical disc 16 on which the hologram data is recorded in an angular overlapping manner, wherein the actuator 14 By changing the incidence angle of the reproduction reference light through the control of, the hologram data superimposed and recorded at the same position of the optical disc 16 is reproduced in units of bits.

The optical disk 16 does not output the reproduction light when the reproduction reference light is incident at an incident angle different from the incident angle of the recording reference light during data recording, and only when the reproduction reference light having the same incident angle as the incident angle of the recording reference light is incident. The reproduction light is output to the light detecting unit 18.

However, in the reproducing apparatus of the holographic ROM system according to the prior art, since the multiplexing information is not recorded in the data superimposition recording on the optical disc 18, there is no way of knowing each information used at the time of recording.

An object of the present invention is to record the mark for scanning the incident angle when recording to a specific position of the holographic optical disk to solve the problems of the prior art as described above, and then enter the servo light into the mark before the data reproduction to adjust the angle used for each multiplexing. The present invention provides a scanning apparatus and a method of a holographic ROM system capable of increasing servo control and data reproducing efficiency by reproducing data after confirmation.

In order to achieve the above object, the present invention provides a holographic ROM reproducing system, comprising: a light source for generating laser light, a data area in which data is overlaid by angular multiplexing, and a mark each time data is overlaid on the data area; And an optical disk comprising an information area in which is superimposed and recorded, a first polarization splitter for transmitting the reference light for reproduction of the laser light and reflecting the servo light, and reflecting the servo light at a predetermined angle on one surface of the optical disk. And a double-sided mirror which reflects the servo light incident and reflected on the optical disk, reflects the reproduction reference light at a predetermined incident angle, and provides the optical disk to the optical disk, and is transmitted through the first polarization separator. A reflection mirror which reflects a reproduction reference light and provides it to the double-sided mirror; A refraction element provided between the double-sided mirror and the reflective mirror and refracting the reproduction reference light to provide the reproduction reference light reflected by the reflection mirror to the double-sided mirror; and driving the refractive element and the double-sided mirror to drive the reproduction reference. A drive system for controlling the position at which the reproduction reference light is incident on the optical disk by changing the refractive index of the light and the reflection angle of the double-sided mirror, and providing servo light reflected by the first polarization separator to one surface of the double-sided mirror, The servo system detects the servo light reflected from one surface of the double-sided mirror and outputs it as an electrical signal, and detects the regenerated light reproduced from the optical disk by the reproduction reference light provided through the double-sided mirror and converts it into an electrical signal. A reproducing means, and output from the servo system when an electrical signal is output from the reproducing means It includes a control unit for storing the electrical signal value in the memory.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

Figure 2 is a block diagram showing a holographic ROM system with each scan function according to the present invention, Figure 3 is a view showing the structure of an optical disk used in the present invention, Figure 4 is a refractive element according to the present invention 5 is a view illustrating the operation of FIG. 5 is a diagram illustrating a structure of a light sensing unit applied to the present invention.

2, the holographic ROM system according to the present invention includes an optical disk 100, a light source 110, a first polarization separator 120, a refractive element 130, a double-sided mirror 132, and a reflective mirror 134. ), The drive system 140, the servo system 150, the controller 160, the memory 170, and the first light detector 180. Unexplained reference numeral 175 denotes a Fourier lens. The first light detecting unit 180 is a reproducing means for reproducing the hologram data in units of bits recorded on the optical disc 100. For example, PD may be used.

First, as shown in FIG. 3, the optical disc 100 marks each time data is overwritten in the data area 100a and data area 100a in which data is overlaid and recorded in bit units in an angular overlapping manner. Is composed of an information area 100b to be superimposedly recorded. The back side of the optical disk 100 is coated with a mirror (not shown). This mirror reflects the servo light incident through the servo system 150.

That is, by the holographic ROM system, an interference fringe due to interference between the recording reference light incident at a predetermined incidence angle and the signal light modulated according to the input data is recorded in the data area 100a, but the incident angle of the recording reference light is changed to be input. The data is overwritten. At this time, whenever the incident angle is changed, a mark is overlaid and recorded in the information area 100b as data incident angle information. At this time, the information area 100b is a lead-in area in which information of the optical disc 100 is recorded.

The light source 110 generates a laser light (for example, a laser light having a wavelength of 532 nm) and provides the laser light to the first polarization splitter 120, and the first polarization splitter 120 is provided when the laser light generated by the light source 110 is incident. It splits into two pieces of light, and transmits the horizontally incident P polarized light as it is and reflects the vertically incident S polarized light. In this case, the light having the P polarization transmitted is defined as the reference light for reproduction, and the light having the reflected S polarization is defined as the servo light.

The double-sided mirror 132 is installed at the front end of the optical disk 100 to reflect the servo light at a predetermined angle to one surface to provide the optical disk 100, and reflect the servo light reflected by the optical disk 100 to the servo system. On the other side, the reproduction reference light is reflected at a predetermined angle of incidence to the optical disk 100 on the other surface.

The reflective mirror 134 reflects the reproduction reference light transmitted through the first polarization separator 120 and provides the reflected reference light to the other surface of the double-sided mirror 132. At this time, the refractive element 130 is provided between the reflective mirror 134 and the double-sided mirror 132, the refractive element 130 changes the incident position as well as the incident angle of the reference light for reproduction in accordance with the rotation of the double-sided mirror 132 It is a means for controlling the incident position. That is, when the reproduction reference light is incident at an arbitrary point of the optical disc 100 at a predetermined incident angle and the reproduction light is not generated from the optical disc 100, the double-sided mirror 132 is changed to change the incident angle of the reproduction reference light. By rotating, the position where the reproduction reference light is incident on the optical disc 100 is changed. In order to prevent the incident position from being changed, the refractive element 130 is driven to change the point at which the reproduction reference light reflected by the reflective mirror 134 is incident on the double-sided mirror 132.

This principle is described below with reference to FIG.

The refractive element 130 used in the present invention is a means for vertically refracting incident light.

That is, as shown in (a) of FIG. 4, when the refractive element 130 is in the correct position, the reproduction reference light passes through the refractive element 130 as it is and enters the point A of the other surface of the double-sided mirror 132. As shown in FIG. 4B, when the refractive element 130 is slightly inclined, the reproduction reference light is vertically refracted to enter the point B of the other surface of the double-sided mirror 132. Accordingly, the position at which the reproduction reference light is incident on the optical disc 100 through the reflection mirror 134, the refractive element 130, and the double-sided mirror 132 is changed. That is, when the incident position of the reproduction reference light is changed by the rotation of the double-sided mirror 132, the incident position of the reproduction reference light may be corrected by driving the refractive element 130.

In other words, the incidence position may be controlled by rotating the double-sided mirror 132 to change the incident angle of the reproduction reference light, and then driving the refractive element 130 to cause the reproduction reference light to enter the same position.

The drive system 140 is driven simultaneously with the first actuator 140a and the first actuator 140a to drive the double-sided mirror 132 to change the incident angle at which the reproduction reference light is incident on the optical disc 100. It is composed of a second actuator 140b for driving the refractive element 130 to control when the incident position changes in accordance with the incident angle change of the light.

The servo system 150 reflects the servo light reflected by the first polarization separator 120 to provide it to the double-sided mirror 132, and detects and receives the servo light generated from the optical disc 100 from the double-sided mirror 132 to detect the electrical signal. As a means for outputting the light source, a second polarization splitter 152, a polarization converting unit 154, a second light sensing unit 156, and a retardation lens 158 are included.

The second polarization separator 152 reflects the servo light having the S polarization reflected from the first polarization separator 120 toward the double-sided mirror 132, and the reflected servo light is polarized by the polarization converter 154. After changing by / 4, the light is incident on one surface of the double-sided mirror 132 through the retardation lens 158. One surface of the double-sided mirror 132 enters the servo light incident through the retardation lens 158 into the information area 100b of the optical disc 100, where the servo light is perpendicular to the information area 100b of the optical disc 100. Incident. At this time, the servo light is reflected by the mirror formed on the back of the optical disk 100 is provided to the double-sided mirror 132, the double-sided mirror 132 is reflected to provide to the polarization converter 154 of the servo system 150. . The reflected servo light is incident on the second polarization separator 152 after its polarization is changed by λ / 4 by the polarization converter 154. The second polarization separator 152 transmits the reflected servo light of P polarized light to provide it to the second light detector 156. As shown in FIG. 5, the second light detector 156 is a two-divided photodiode. The second light detector 156 is configured as a photodiode of an A region and a B region, and outputs an electrical signal value 1 by sensing the amount of servo light in the A region. In addition, the light amount of the servo light is detected in the region B, and the electrical signal value 2 is output to the controller 160. The amount of light detected in areas A and B of the second light detector 156 may vary depending on the angle of the double-sided mirror 132.

On the other hand, the reproduction reference light is incident on the information area 100b of the optical disc 100 by adjusting the incident angle by the double-sided mirror 132, and the reproduction reference light is input to the information area 100b of the optical disc 100. When the incident angle at the time of incidence is equal to the incident angle of the recording reference light when the mark is recorded in the information area 100b, the information area 100b of the optical disc 100 removes the reproduced light reproduced by the reference light for reproduction. 1 is output to the light detecting unit 180, otherwise the reproduction light is not output.

The first optical detector 180 radiates the reproduction reference light to the information area 100b of the optical disc 100 and reproduces the data output from the information area 100b of the optical disc 100 when data is reproduced in units of bits. The light is converted into electrical data and output to the controller 160.

In addition, when the data is reproduced in units of bits by reproducing the reference light for reproduction to the information area 100b of the optical disc 100, the first optical detector 180 outputs the information from the information area 100a of the optical disc 100. The reproduced light is converted into electrical data and output.

The controller 160 not only controls the first and second actuators 140a and 140b of the driving system 140, but also the second light as the incident angle information of the reproduction reference light when electrical data is input from the first light detector 180. The difference between the electrical signal values 1 and 2 output from the areas A and B of the detector 156 is stored in the memory 170. As such, based on the information stored in the memory 170, the controller 160 controls the double-sided mirror 132 by driving the drive system 140 to control the incidence angle of the reference light for reproduction, and the servo system 150 during data reproduction. By comparing the signal value output through the information stored in the memory 170 and it can be seen whether the servo control is properly performed. That is, if the signal values output through the servo system 150 match the information stored in the memory 170, it means that the servo control is properly performed.

As described above, when data recorded on the optical disc 100 is reproduced by the holographic ROM system, the reproduction process will be described as follows.

First, when the optical disc 100 is loaded into the holographic ROM system, the holographic ROM system scans the information area 100b of the loaded optical disc 100 to extract incident angle information.

That is, the controller 160 controls the first and second actuators 140a and 140b of the drive system 140 such that the servo light and the reproduction reference light are incident on an arbitrary position of the information area 100b of the optical disc 100.

Accordingly, the laser light generated by the light source 110 (for example, laser light having a wavelength of 532 nm) is transmitted to the first polarization separator 120, and the first polarization separator 120 splits the laser light into two lights. That is, the first polarization separator 120 transmits the P-polarized light that is horizontally incident, that is, the reproduction reference light, and reflects the S-polarized light that is vertically incident, that is, the servo light.

As described above, the servo light separated by the first polarization separator 120 is reflected by one surface of the double-sided mirror 132 through the servo system 150 to be incident on the information area 100b of the optical disc 100. Servo light incident on the information area 100b of the optical disk 100 is reflected by a mirror formed on the rear surface of the optical disk 100 and then reflected by one surface of the double-sided mirror 132 and then passes through the servo system 150. The detected light is converted into an electrical signal and input to the controller 160.

At this time, when the reproduction reference light is incident on the information area 100b at the same incidence angle as the recording reference light at the time of data recording, the reproduction light having the data image of a bit unit composed of original pixel contrast in the information area 100b where the mark is recorded. The first light detector 180 outputs the light to the first light detector 180, and does not output the reproduced light.

When the reproduced light is output, the first light detector 180 detects the reproduced light, converts the converted light into electrical data, and outputs the converted light to the controller 160. The controller 160 outputs electrical data from the first light detector 180. When input, the difference between the electric signal values 1 and 2 of the servo light sensed in areas A and B of the second light detector 156 is stored in the memory 170 to record incident angle information of the reproduction reference light.

When the reproduction light is not output, the controller 160 controls the double-sided mirror 132 and the refractive element 130 by driving the first and second actuators 140a and 140b of the drive system 140 and the incident angle of the reference light for reproduction. It is determined whether the reproduction light is output by controlling the incident position.

By repeatedly performing such a process, the controller 160 outputs the reproduction light from the information area 100b of the optical disc 100 by the information necessary for reproducing the data recorded in the data area 100a, that is, the reproduction reference light. Information stored in the memory 170 after storing the electrical signal values output from the second light detector 156 at the time and the positions of the double-sided mirror 132 and the refractive element 130 at the time. Based on these, data reproduction is performed.

Referring to the data reproduction process, first, the controller 160 controls the incident angle of the servo light and the reproduction reference light by driving the drive system 140 based on the information stored in the memory 170, and then reflects the reproduction reference light to the reflection mirror 134 and While entering the data area 100a of the optical disk 100 through the other side of the double-sided mirror 132, the servo light is also incident on the data area 100a through the one surface of the servo system 150 and the double-sided mirror 132. Let's do it.

At this time, the servo light reflected by the optical disk 100 is detected by the second light detector 156, and then the servo control is normally performed by comparing the difference between the electric signal values based on the detected light amount and the information stored in the memory 170. Determine if it is done. That is, if the difference between the information stored in the memory 170 and the electrical signal values output from the second optical sensor 156 when data is reproduced, the servo control is normally performed. Otherwise, the servo control is not properly performed. will be.

When Servo Control is Properly Performed When the reference light for reproduction enters the data area 100a of the optical disc 100, data in bit units composed of original pixel contrasts in the data area 100a of the optical disc 100 is provided. The reproduction light having the image is transmitted to the first light detector 180 through the Fourier lens 175.

The first light detector 180 converts reproduction light having a binary pixel data image in units of bits into electrical data, and the converted data is restored to original data through an image signal processor, a decoder, and the like, which are not shown.

As described above, the present invention records the mark for the incident angle scan when recording at a specific position of the holographic optical disk, and then enters the servo light into the mark before reproducing the data to check the angle used for each multiplexing, thereby reproducing the data. There is an effect to increase the control and data reproduction efficiency.

On the other hand, the present invention is not limited to the above-described embodiment, various modifications are possible by those skilled in the art within the spirit and scope of the present invention described in the claims to be described later.

Claims (8)

Holographic ROM playback system, A light source for generating laser light, An optical disk comprising a data area in which data is superimposed and recorded by angular multiplexing, an information area in which marks are superimposed and recorded each time data is superimposed and recorded in the data area; A first polarization separator configured to transmit a reference light for reproduction of the laser light and reflect servo light; It is installed at the front end of the optical disk and reflects the servo light at a predetermined angle to one surface to provide to the optical disk, and reflects the servo light incident and reflected on the optical disk, and reflects the reproduction reference light at a predetermined incident angle A double-sided mirror provided to the optical disc, A reflection mirror which reflects the reproduction reference light transmitted by the first polarization separator and provides the reflection reference light to the double-sided mirror; A refracting element provided between the double-sided mirror and the reflective mirror and refracting the reproduction reference light to provide the reproduction reference light reflected by the reflection mirror to the double-sided mirror; A drive system for controlling the position at which the reproduction reference light is incident on the optical disk by driving the refractive element and the double-sided mirror to change the refractive index of the reproduction reference light and the reflection angle of the double-sided mirror; A servo system that provides the servo light reflected by the first polarization splitter to one surface of the double-sided mirror, detects the servo light reflected from one surface of the double-sided mirror, and outputs it as an electrical signal; Reproducing means for detecting and reproducing and outputting the reconstructed light reproduced from the optical disk by the reproducing reference light provided through the double-sided mirror; Control unit for storing the electrical signal value output from the servo system in the memory when the electrical signal is output from the reproducing means Each scanning device of the holographic ROM system comprising a. The method of claim 1, The drive system, A first actuator for driving the double-sided mirror to change reflection angles of the reproduction reference light and the servo light; A second actuator which rotates the refractive element and controls an incident position of the reproduction reference light Each scanning device of the holographic ROM system comprising a. The method of claim 1, The servo system, A polarization converting unit for polarizing the servo light reflected from the double-sided mirror, polarizing the servo light, and providing the polarized light to the double-sided mirror; A second polarization separator reflecting the servo light reflected by the first polarization separator and transmitting the servo light reflected by the double-sided mirror and polarized by the polarization converting unit; A light detector for detecting the servo light transmitted through the second polarization splitter to convert the light into an electrical signal Each scanning device of the holographic ROM system comprising a. The method of claim 3, wherein The polarization converting unit, each scan device of the holographic ROM system, characterized in that consisting of λ / 4 plate. The method of claim 3, wherein The optical sensing unit is a scanning device of a holographic ROM system, characterized in that consisting of two divided photodiode divided into two areas. The method of claim 5, The light detector detects the servo light in each of the divided regions and outputs the servo signal as an electrical signal. And the control unit stores the difference value between the electrical signal values of the divided regions when the electrical signal is output from the reproducing unit. The method of claim 1, The control unit controls each of the driving systems based on the electrical signal values stored in the memory when the data recorded in the data area is reproduced to change the incident angle and the incident position of the reference reference light for reproducing each holographic ROM system. Device. The method of claim 1,  And said information area is a lead-in area of said optical disc.

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