KR20060067626A - Recoding and reading device of the holographic rom system - Google Patents

Abstract

The present invention relates to a recording apparatus and a reproducing apparatus of a holographic ROM system. In particular, the recording apparatus of the present invention includes a polarizer for modifying a laser light of a light source so that only one polarization exists, and hologram data information. A recording mask which transmits the laser light of the polarizer passing through the defined data pattern to the signal light and transmits the laser light of the polarizer passing through the reference light pattern in which the recording material layer selection information is defined as the reference light, and at least one or more hologram data is recorded. The signal light having the recording material layer and passing through the data pattern of the recording mask is transmitted to the entire optical recording medium, and the reference light passing through the reference light pattern of the recording mask is transmitted to any one of the recording material layers to It includes an optical record carrier on which hologram data is recorded due to interference. Therefore, the present invention can increase the storage capacity of the hologram data recorded on the disk and is a simple invention of the configuration of the recording apparatus.

Hologram ROM System, Recording Mask, Multiple Layers of Recording Material

Description

RECORDING AND READING DEVICE OF THE HOLOGRAPHIC ROM SYSTEM}

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

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

3 is a block diagram showing a recording apparatus of the holographic ROM system according to the present invention;

4 shows a recording mask used in the recording apparatus of the holographic ROM system according to the present invention;

5A and 5B are views for explaining reference light incident on a recording material layer of a recording medium in the recording apparatus of the holographic ROM system according to the present invention;

6 is a view for explaining the angle of the incident light according to the refractive index of the medium,

7 is a block diagram showing a playback device of the holographic ROM system according to the present invention;

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

100, 150: light source 102: HWP

104: magnifying lens 106: polarizer

108: recording mask 108a: reference light pattern

108b: data pattern 110: disk

152: Reducer 154: Aperture

158: objective lens 160: slit

162: condenser lens 164: light detector

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a holographic memory, and more particularly to a recording apparatus and a reproducing apparatus of a holographic ROM system capable of increasing the storage capacity of holographic data recorded on a disc, which is an optical recording medium.

As the information industry develops, a large capacity of a device for storing information and a high speed of processing are required. Holographic memory that can store hundreds to hundreds of Gbytes on optical recording media such as disks for high capacity and high speed processing of current data storage memory. Among them, Holographic ROM (HROM: Holographic ROM) is the next generation mass storage device. The research and development of this product is actively underway.

1 is a block diagram illustrating a recording apparatus of a holographic ROM system according to the related art. Referring to FIG. 1, a recording apparatus of a conventional holographic ROM system includes a light source 10, mirrors 20, 26, and 28, a polarizer beam split (PBS) 16, and a conical mirror 30. And a data mask 34 and an optical record carrier 32 (hereinafter referred to as a disk). 12 and 22 are half wave plates (HWP), 14 are magnification lenses, and 18 and 24 are polarizers.

The laser light of the light source 10 has a polarization characteristic of P type or S type. The laser light is transformed into light having P-type and S-type polarization through the HWP 12, and the light is magnified to a predetermined size through the magnifying lens 14 and transmitted to the polarized light splitter (PBS) 16.

The polarized light splitter (PBS) 16 reflects the light of the vertical S polarization component and transmits the light of the horizontal P polarization component as it is. Accordingly, the P-polarized light transmitted through the polarized light splitter (PBS) 16 as it is is transmitted to the polarizer 18 along the signal light S2 path. The polarizer 18 makes light having only pure P polarization and transmits it to the mirror 20. The mirror 20 reflects the light of the P-polarized component vertically and transmits it to the entire upper portion of the data mask 34 so that it is parallel to the upper portion of the disk 32 which is the entire optical recording medium through an on / off bit pattern of the data mask 34. The signal light S2 of P polarization is incident.

The S-polarized light reflected by the polarized light splitter (PBS) 16 is transmitted to the HWP 22 along the reference light path. The HWP 22 transforms the light of the S-polarized light into λ / 2 to make P-polarized light, and the polarizer 24 to produce light having only the P-polarized light, and transmits the light to the mirrors 26 and 28. . The mirrors 26 and 28 reflect the light of P polarization vertically and transmit the light to the conical mirror 30 to reflect the light of P polarization at a predetermined angle through the inclined mirror surface of the conical mirror 30. The reference light S1 of parallel P polarization is incident on the lower portion of the phosphor disk 32.

Accordingly, the signal light S2 of P-polarized light and the reference light S1 of P-polarized light meet with the recording material layer in the disk 32 and interfere with each other to record hologram data according to the bit pattern of the data mask 34. In this case, since the signal light and the reference light incident on the disk 32 must be of the same polarization type to cause interference, the above-described recording apparatus can record the same data even if the signal light and the reference light polarization incident on the disk 32 are replaced with the S-type polarized light. have.

As described above, when the recording apparatus of the holographic ROM system replaces the data mask 34 and replaces the conical mirror 30 with different inclination angles, the recording of the hologram data is superimposed on the recording material layer of the disk 32. This is possible.

2 is a block diagram illustrating a playback apparatus of a holographic ROM system according to the related art. Referring to FIG. 2, a reproducing apparatus of a conventional holographic ROM system includes a light source 40, an aperture 44, a mirror 46, a disc 32, a slit 52, and a photo detect IC. 56).

Here, the laser light of the light source 10 has the same polarization characteristic as in recording. A reducer 42 is provided between the light source 40 and the aperture 44 to deform the light, and between the disc 32 and the slit 52 to form light reproduced from the disc 32. An objective lens 50 is provided. In addition, a condenser lens 54 may be disposed between the slit 52 and the light detector 56 to collect and transmit light passing through the pinhole of the slit 52 to the light detector 56. 48 denotes a spindle motor for rotating the disc 32 at a constant speed during regeneration.

When the laser light of the light source 40 is incident on the mirror 46 through the reducer 42 and the aperture 44, the mirror 46 emits the laser light (that is, the phase conjugate wave of the reference light) at the same angle of incidence upon recording. It enters into the disk 32.

The reference light incident on the disk 32 is diffracted and reproduced by hologram data, which is an interference fringe recorded on the recording material layer inside the disk 32, and the reproduced light is imaged by the objective lens 50. At this time, since the diameter of the reference light incident on the disk 32 has a size of about 100 μm, the light formed through the objective lens 50 includes reproduction light of data recorded in many tracks of the disk 32.

The reproduced light formed on the objective lens 50 passes through the pinhole of the slit 52 and is collected by the condenser lens 54 and transmitted to the light detector 56, and decodes light detected through a circuit such as a decoder to decode the disc. The data recorded at 32 is reproduced. At this time, since the pinhole size of the slit 52 has a size of 1 bit of data, only one data bit of one track passes through the pinhole among the many track data reproduced, and the regenerated light passing through the pinhole passes through the condensing lens 54. It is transmitted to the light detector 56.

However, the holographic ROM system having such a recording device and a reproduction device requires high precision of the conical mirror angle in order to maintain the same reference light incident angle during reproduction. In addition, when the focal length between the objective lens and the disc becomes closer during reproduction, the incident angle of the reference light is limited, thereby limiting the number of multiplexing. In addition, there is a problem that the reproduction speed of the hologram data is slowed down because data is detected in units of one bit during reproduction. In addition, the conventional holographic ROM system can improve the storage density by improving the angular selectivity as the thickness of the optical record medium chain disk increases, but it is difficult to increase the thickness so as to have uniform characteristics. There was a limit to increase.

Therefore, research and development of a new recording device and a reproducing device are required to overcome the problems and limitations of the holographic ROM system described above.

SUMMARY OF THE INVENTION An object of the present invention is to provide a disk having at least one recording material layer, a reference light pattern for injecting reference light into one recording material layer, and a signal light pattern for injecting signal light in order to solve the above problems of the prior art. By providing a recording mask, it is possible to increase the storage capacity of the hologram data recorded on the disk, and to provide a recording device of the holographic ROM system which simplifies the configuration of the recording device.

Another object of the present invention is to provide a reproducing apparatus of a holographic ROM system capable of simultaneously reproducing hologram data recorded on a recording material layer of a disc, thereby increasing the reproduction speed.

In order to achieve the above object, the present invention provides a recording apparatus of a holographic ROM system for recording hologram data, comprising: a polarizer for transforming a laser light of a light source so that only one polarization exists, and a data pattern in which hologram data information is defined. A recording mask which transmits the laser light of one polarizer to the signal light and transmits the laser light of the polarizer passing through the reference light pattern in which the recording material layer selection information is defined to the reference light, and at least one layer of recording material on which the hologram data is recorded; The signal light passing through the data pattern of the recording mask is transmitted to the entire optical recording medium, and the reference light passing through the reference light pattern of the recording mask is transmitted to one of the recording material layers so that the hologram data is transferred due to interference of the signal light and the reference light in the recording material layer. And an optical record carrier to be recorded.

In order to achieve the above another object, the present invention provides a reproducing apparatus of a holographic ROM system for reproducing hologram data of an optical recording medium having at least one recording material layer, wherein the laser beam is applied to any recording material layer position of the optical recording medium. A moving light source for incident, a slit for passing a portion of the reproduced light from the data of the recording material layer into which the laser light is incident, and a moving light detection unit for detecting the reproduction light incident through the slit.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

3 is a block diagram illustrating a recording apparatus of the holographic ROM system according to the present invention. Referring to FIG. 3, the recording apparatus of the holographic ROM system according to the present invention includes a light source 100, a HWP 102, a magnification lens 104, a polarizer 106, a recording mask 108, and an optical recording medium. 110.

The laser light of the light source 100 has a polarization characteristic of P type or S type.

HWP 102 will make the incident laser light into S-polarized light. When the laser light has a P-type polarization characteristic, the direction of polarization is rotated λ / 2 to become S-polarized light, and when the laser having an S-polarized light component is used, the HWP 102 can be omitted.

The magnification lens 104 magnifies the light incident through the HWP 102 to a polarizer 106 in a predetermined size.

The polarizer 106 removes the light of the P-polarized component which may be mixed in a small amount to the light of the S-polarized light enlarged through the magnification lens 104 to make the light of the S-polarized light purely and provides it to the recording mask 108. .

The recording mask 108 of the present invention includes the data pattern 108b in which the hologram data information is defined and the reference light pattern 108a in which the recording material layer selection information of the disk 110 is defined. The signal is transmitted to the disk 110 as signal light, and the light passing through the reference light pattern is transmitted to the disk 110 as reference light. The data pattern of the recording mask 108 consists of a hole pattern or a light blocking pattern, and the reference light pattern consists of a ring pattern hole pattern or a light blocking pattern. In addition, at least one reference light pattern of the recording mask 108 is provided to select all of the recording material layers of the disk 110.

The disc 110 has at least one layer of recording material, and includes a cladding layer having a refractive index smaller than that of the recording material layer between the recording material layers. And the central portion of the disk 110 has an inclined reflective layer. In addition, the disk 110 may form a plurality of recording material layers by recording in one recording material layer, additionally forming (gluing) the cladding layer and the recording material layer, and then recording again in the added recording material layer.

The recording apparatus of the holographic ROM system according to the present invention configured as described above operates as follows.

The laser light having the P-type polarization or the S-type polarization characteristics generated by the light source 100 is transformed into the light of the S-type polarization through the HWP 102 and the light is magnified to a certain size through the magnifying lens 104. Delivered to the polarizer 106.

Light of the S-polarized light is transformed into light having only the S-polarized component through the polarizer 106 and transmitted to the recording mask 108.

Light of the S-polarized light of parallel light transmitted through the data pattern of the recording mask 108 is incident on the disk 110 as a signal light. The light of the S-polarized light of the parallel light transmitted through the reference light pattern in the center portion of the recording mask 108 is incident to any one recording material layer in the disc 110 as the reference light, and to the end of the recording material layer surrounded by the cladding layer. It is spread. In this case, the reference light is incident to the center portion of the disk 110.

Accordingly, in the corresponding recording material layer of the disk 110, the reference light of the horizontally S-polarized light propagated horizontally and the signal light incident vertically interfere with each other to record hologram data according to the data pattern. In this case, the signal light and the reference light incident on the disk 110 must be of the same polarization type to cause interference, and since the two lights are perpendicular to each other, the light incident on the disk 110 through the recording mask 108 is a component of the S polarization component. It must be light. If the propagation direction of the two lights is not perpendicular, the light of P polarization can also be used.

As described above, when recording is performed by changing the reference light mask 120 having a different reference light selection pattern in the recording apparatus of the holographic ROM system according to an exemplary embodiment of the present invention, hologram data is also recorded in another recording material layer of the disc 122. It is possible to record.

In addition, the recording apparatus of the holographic ROM system according to the present invention includes a plurality of reference light patterns of the recording mask 108 such that a plurality of reference lights transmitted through the reference light pattern through each of the plurality of recording material layers of the disc 110 are simultaneously displayed. Incidental input allows recording of a plurality of layers of recording material in a single recording.

In addition, the recording apparatus of the holographic ROM system according to the present invention has a diffraction efficiency of each recording material layer to be 30% or less in order to reduce noise between the recording material layers when recording the hologram data in the recording material layer of the disc 110. do. The signal-to-noise ratio (SNR) is then 1 / 0.09 when the diffraction efficiency is 30%.

4 shows a recording mask used in the recording apparatus of the holographic ROM system according to the present invention.

Referring to Fig. 4, the recording mask 108 of the present invention includes a reference light pattern 108a for injecting reference light into any one of the plurality of recording material layers constituting the disc. In this case, the reference light pattern 108a may be formed of a ring pattern hole pattern or a light blocking pattern for transmitting the reference light at the center portion of the disk. At least one reference light pattern 108a of the recording mask 108 is provided for simultaneously selecting the recording material layer of the disc.

In addition, the recording mask 108 of the present invention is formed at regular intervals on the outer portion of the reference light pattern 108a and includes a data pattern 108b for injecting signal light having hologram data information into the recording material layer of the disc. do. In this case, the data pattern 108b is formed of a hole pattern or a light blocking pattern representing on / off data bits.

5A and 5B are views for explaining reference light incident on a recording material layer of a recording medium in the recording apparatus of the holographic ROM system according to the present invention.

5A and 5B, since the central portion of the disk 110 of the present invention has a reflective layer, such as a conical form, at least one or more recording material layers in the disk 110 each have the same angle. Accordingly, the reference light Sr incident through the reference light pattern of the recording mask is incident on one of the recording material layers 110a designated by the reference light pattern and propagates to the end of the recording material layer 110a surrounded by the cladding layer 110b. The signal light Ss incident through the data pattern of the recording mask is incident on the entire disk 110 designated by the data pattern except for the reference light pattern.

Referring to FIG. 6, when the refractive index of the medium 1 is n1 and the refractive index of the daily 2 is n2, and the light incident angle at this time is a1, the following equation 1 is obtained.

If the angle of incidence is greater than the above conditions, all the light will be reflected.

Therefore, since the refractive index of the cladding layer 110b is smaller than that of the recording material layer 110a, the reference light Sr incident upon recording propagates from the center portion of the disc to the end portion without leaving the recording material layer.

7 is a block diagram showing a playback device of the holographic ROM system according to the present invention.

Referring to FIG. 7, the reproducing apparatus of the holographic ROM system according to the present invention includes a movable light source 150, a reducer 152, an aperture 154, a disc 110, an objective lens 158, and a slit 160. , A condenser lens 162, and a movable light detector 164.

Here, the light source 150, the reducer 152, the aperture 154, and the like, which are optical devices for injecting the laser light of the movable light source 150 into the disk 110, are formed on the first surface (upper surface) of the disk 110. The objective lens 158, the slit 160, the condenser lens 162, the light detector 164, and the like, which are optical devices disposed on the optical disk and receive the light reproduced by the disk 110, are opposite parts of the disk 110. It is arrange | positioned at the 2nd surface (lower surface) which is phosphorus.

The laser light of the movable light source 150 has the same polarization characteristic as in recording and injects the laser light at an arbitrary recording material layer position in the disk 110. At this time, the light source 150, the reducer 152, and the aperture 154 are composed of one set so that the light source 150, the reducer 152, and the aperture 154 can be moved horizontally in accordance with the position selection of the recording material layer.

The movable light detector 164 also detects a portion of the light reproduced from any layer of recording material of the disk 110 through the slit 162. In this case, the objective lens 158, the slit 160, the condenser lens 162, and the movable light detector 164 may be configured as one set to move horizontally along the track position of the disc 110.

The reproducing apparatus of the holographic ROM system according to the present invention configured as described above operates as follows.

The laser light of the movable light source 150 causes the laser light to enter the position of one recording material layer of the same disk 110 when recording through the reducer 152 and the aperture 154.

The laser light incident on the recording material layer of the disc 110 propagates from the center portion of the disc 110 to the end portion along the corresponding recording material layer surrounded by the cladding layer, and by hologram data which is an interference fringe by the propagated light. Diffracted reproduction light is emitted to the lower surface of the entire disk 110.

The reproduced light emitted from the entire disk 110 is formed by the objective lens 158 provided on the lower surface of the disk 110, and the reproduced light formed in the objective lens 158 is focused after passing through the pinhole of the slit 160. The light is collected by the lens 162 and transferred to the movable light detector 164. The light detected by the mobile light detector 164 is decoded by a circuit such as a decoder to reproduce the hologram data recorded on the disc 110. At this time, since the pinhole size of the slit 160 has a size of 1 bit of data, only one data bit of one track passes through the pinhole among the many track data reproduced, and the regenerated light passing through the pinhole is collected through the condensing lens 162. It is transmitted to the movable light detector 164.

In addition, the reproducing apparatus of the holographic ROM system according to the present invention includes one moving light source and a plurality of moving light detectors, and at this time, an optical device (for example, an objective lens and a slit) to which the reproduced light is transmitted from the disc 110. And a plurality of condensing lenses) are also configured in each set. According to the present invention, the reproduction speed of the holographic ROM system can be accelerated by detecting the light reproduced in the recording material layer from one light source by the plurality of light detectors.

In addition, the shape of incident light during reproduction may be a ring type. Use parallel light for one layer. In case of ring type, it can read all the information of a single disk, but it is easy for general consumers to own the system, and in case of using one parallel light, only the data on the line of light can be read. This part can be overcome.

As described above, the conventional reference light incident angle is limited because the conical mirror is not used by the recording apparatus of the holographic ROM system of the present invention.

In addition, since the recording apparatus of the present invention includes a disk having at least one recording material layer, the storage capacity of the hologram data recorded on the disk can be increased.

In addition, the recording apparatus of the present invention can simplify the configuration of the recording apparatus because the incident light and the reference light are incident on the disk through one mask.

In addition, the reproducing apparatus of the holographic ROM system of the present invention can reproduce hologram data recorded in each of the recording material layers of the disc at the same time, thereby increasing the reproduction speed.

The present invention is not limited to the above-described embodiments, but various modifications may be made by those skilled in the art within the spirit and scope of the present invention described in the following claims.

Claims (11)

A recording apparatus of a holographic ROM system for recording hologram data, A polarizer for modifying the laser light of the light source so that only one polarization exists; A recording mask which transmits the laser light of the polarizer passing the data pattern in which the hologram data information is defined as a signal light and the laser light of the polarizer passing the reference light pattern in which the recording material layer selection information is defined as a reference light; The recording material layer having at least one recording material layer on which the hologram data is recorded, the signal light passing through the data pattern of the recording mask is transmitted to the entire optical recording medium, and the reference light passing through the reference light pattern of the recording mask is either recording material layer. Is transmitted to the optical recording medium in which the hologram data is recorded due to the interference of the signal light and the reference light in the corresponding recording material layer. The recording device of the holographic ROM system comprising a. The method of claim 1, And the optical recording medium comprises a cladding layer between the recording material layers and having a lower refractive index than the recording material layer. The method of claim 1, And a data pattern of the recording mask is a hole pattern or a light blocking pattern. The method of claim 1, The reference light pattern of the recording mask is a recording device of a holographic ROM system, characterized in that consisting of a ring-shaped hole pattern or light blocking pattern. The method of claim 1, And at least one reference light pattern of the recording mask is provided to select all the recording material layers of the optical recording medium. The method of claim 1, And a central portion of the optical record carrier has an inclined reflective layer. The method according to claim 1 or 6, And the reference light is incident on a central portion of the optical recording medium. The method of claim 1, And a signal light and a reference light incident on the optical recording medium through the recording mask are of the same polarization. A reproducing apparatus of a holographic ROM system for reproducing hologram data of an optical recording medium having at least one recording material layer, A movable light source for injecting laser light into an arbitrary recording material layer position on the optical recording medium; A slit for passing a portion of the light reproduced from the data of the recording material layer to which the laser light is incident; A movable light detector for detecting the reproduction light incident through the slit Reproducing apparatus of the holographic ROM system comprising a. The method of claim 9, And the movable light source is disposed on a first surface of the optical record carrier, and the slit and the movable light detector are disposed on a second surface opposite to the optical record carrier. The method of claim 9, The movable light source includes at least two movable light sources and at least two movable light detectors to inject the laser light into each recording material layer of the optical recording medium in the movable light source, and to reproduce the data from each recording material layer in the movable light detector. A reproducing apparatus of a holographic ROM system, characterized in that it simultaneously detects light.

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