KR100477476B1 - Volume holographic digital storage system with error checking - Google Patents

Abstract

The present invention relates to a volume holographic digital storage system having an error check function for storing an interference fringe generated by interfering a light modulated object light and a reference light in a page unit of data in a storage medium. Light source 105 for generating a; A first optical splitter 110 for separating the laser beam of the first polarization into the reference light of the first polarization and the object light of the first polarization; A first reflection mirror 125 reflecting the first reference light of the first polarization; A second reflecting mirror 115 reflecting the object light of the first polarized light; A second optical splitter (155) for separating the object light of the first polarization reflected by the second reflection mirror (115) into a second reference light of the first polarization and an object light of the first polarization; A third reflective mirror 120 reflecting the second reference light of the first polarized light separated by the second optical splitter 155; A λ / 2 plate (160) for rotating the second reference light of the first polarization reflected by the third reflection mirror (120) by 90 ° to convert it into a second reference light of the second polarization; A fourth reflection mirror 130 reflecting the second reference light of the second polarization; The first polarized object light separated by the second optical splitter 155 is modulated in units of pages of data input from the outside, and the first and second polarized object lights and the second polarized light according to the input data are modulated. A spatial light modulator 140 for light modulating the object light; An interference fringe by interference between the first reference light of the first polarization and the object light of the first polarization, and an interference fringe by interference between the second reference light of the second polarization and the object light of the second polarization is recorded, A storage medium 145 that reproduces object light of first polarization when the first reference light of the first polarization is irradiated, and reproduces object light of second polarization when the second reference light of the second polarization is irradiated; A CCD (150) for converting the object light reproduced in the storage medium (145) into an electrical signal; A digital signal processor 165 for digitally processing the output signal of the CCD 150 and outputting an image signal; An image signal processor 170 for performing image signal processing on the digital signal processed image signal; And a monitor 175.

Description

Volume holographic digital storage system with error checking

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a volume holographic digital data storage system for storing hologram data in units of pages based on an interference fringe generated by interfering an object light and a reference light from an object. A volume holographic digital storage system with a check function is provided.

Recently, the field of technology using volume holographic digital data storage has been actively researched due to the remarkable development of components such as semiconductor laser, charge coupled device (CCD), liquid crystal display (LCD), and fingerprint storage. In addition to being used as a fingerprint recognition system to play and play, there is a trend of expanding to various fields that can apply the advantages of large storage capacity and ultra-fast data transfer speed.

Such a volume holographic digital storage system records an interference fringe generated by interfering an object light and a reference light from a target object in a storage medium, for example, a crystal, which responds to the amplitude of the interference fringe. By recording the intensity and the direction of the object light by changing the angle of the reference light, it is possible to display the three-dimensional image of the object, and place hundreds to thousands of holograms composed of pages of binary data in the same place. Can be stored in.

Figure 1 shows the overall configuration of such a volume holographic digital storage system.

As shown in FIG. 1, a volume holographic digital storage system includes a light source 10, a light splitter 20, reflective mirrors 30 and 40, a liquid crystal display (LCD) 50, a storage medium ( 60) and the CCD 70.

The light source 10 generates laser light required for holography, and the optical separator 20 separates the laser light input from the light source 10 into reference light and object light, and then transmits the separated reference light and object light different from each other. Follow the path.

On the other hand, the reference light separated by the optical separator 20 is incident on the reflection mirror 30, and then reflected again and transmitted to the storage medium 60.

In addition, the object light is incident on the reflection mirror 40 and then reflected again and transmitted to the LCD 50. The object light provided to the LCD 50 is transmitted to the storage medium 60 after being modulated in units of one page of the binary data of the contrast made by the pixels according to the input data.

The storage medium 60 stores an interference fringe generated by interference between the reference light reflected by the reflection mirror 30 and the object light modulated by the LCD 50, wherein the interference fringe is described above in the LCD 50. This corresponds to the data entered in.

The operation of the volume holographic digital storage system configured as described above is as follows.

First, the laser light generated by the light source 10 is separated into the reference light and the object light by the optical separator 20, and then the reference light is transmitted to the reflection mirror 30 and the object light is transmitted to the reflection mirror 40, respectively. The object light reflected by the reflecting mirror 40 is incident on the LCD 50, and the object light incident on the LCD 50 is one of the binary data of the contrast that the pixels make according to the data input to the LCD 50. Modulated in units of pages.

That is, when the data input to the LCD 50 is image data provided in units of one frame of an image, for example, the object light incident on the LCD 50 is modulated in units of one frame. On the other hand, when the LCD 50 modulates the incident object light in units of pages, the reflection mirror 30 serves to change the reflection angle of the reference light little by little.

Accordingly, the object light light-modulated in units of pages and the reference light at an angle corresponding thereto are incident on the storage medium 60, and the incident object light and the reference light cause interference within the storage medium 60. At this time, the light induced phenomenon of the kinetic charge in the storage medium 60 occurs according to the intensity of the generated interference fringes, and through this process, the interference fringes are recorded in the storage medium 60.

On the other hand, in order to read the data recorded in the storage medium 60, if only the reference light is irradiated to the storage medium 60, the interference fringe is diffracted into the checkered pattern consisting of the contrast of the original pixel by diffracting the reference light, and then read The image is restored to the original data in the light of a CCD (Charge Coupled Device) 70 or the like. At this time, the reference light that has been applied to read the data recorded on the storage medium 60 should apply a reference light having substantially the same intensity and angle as the reference light applied when the data is recorded on the storage medium 60.

However, such a volume holographic digital storage system has only a function of recording and reproducing hologram data on a storage medium, and does not have a function of checking an error of whether the hologram data is correctly recorded and reproduced on the storage medium.

Accordingly, an object of the present invention is to provide a volume holographic digital storage system having an error check function.

In order to achieve the above object, the present invention provides a volume holographic digital storage system for storing an interference fringe generated by interfering a light modulated object light and a reference light in a page unit of data in a storage medium. Generating a light source; A first optical splitter separating the laser beam of the first polarization into a reference light of the first polarization and an object light of the first polarization; A first reflection mirror reflecting the first reference light of the first polarization; A second reflection mirror that reflects the object light of the first polarization; A second optical splitter separating the object light of the first polarized light reflected by the second reflection mirror into a second reference light of the first polarized light and an object light of the first polarized light; A third reflecting mirror reflecting a second reference light of the first polarized light separated by the second optical splitter; A λ / 2 plate for rotating the second reference light of the first polarization reflected by the third reflection mirror by 90 ° to convert the second reference light to the second reference light of the second polarization; A fourth reflection mirror reflecting the second reference light of the second polarization; The object light of the first polarized light separated by the second optical splitter is modulated by a page unit of data input from the outside, and the object light of the first polarized object light and the second polarized light according to the input data are modulated. Spatial light modulator for light modulation; An interference fringe by interference between the first reference light of the first polarization and the object light of the first polarization, and an interference fringe by interference between the second reference light of the second polarization and the object light of the second polarization is recorded, A storage medium for reproducing an object light of a first polarized light when irradiating the first reference light of the first polarized light, and reproducing an object light of the second polarized light when irradiating a second reference light of the second polarized light; A CCD for converting the object light reproduced from the storage medium into an electrical signal; A digital signal processor for outputting an image signal by digitally processing the output signal of the CCD; An image signal processor configured to perform image signal processing on the digital signal processed image signal; And a monitor.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

2 is a detailed block diagram of a volume holographic digital storage system having an error check function according to a preferred embodiment of the present invention.

In FIG. 2, a volume holographic digital storage system having an error check function according to a preferred embodiment of the present invention includes a light source 105, a first optical splitter 110, a reflective mirror 115, 120, 130, 135, an optical modulator 140, The storage medium 145, the CCD 150, the second optical splitter 155, the λ / 2 plate 160, the digital signal processor 165, the image signal processor 170, and the monitor 175. do. Meanwhile, in FIG. 2, 에서, ↔, Is the polarization direction of light. For example, 수직 is vertical polarization, ↔ is horizontal polarization, Represents horizontal / vertical polarization.

A volume holographic digital storage system having an error check function according to a preferred embodiment of the present invention configured as described above is as follows.

First, the light source 105 generates, for example, a laser beam of vertical polarization and provides it to the first optical separator 110. The first optical splitter 110 separates the laser beam of the vertically polarized light into the first reference light and the object light, and the reference light of the vertically polarized light is reflected by the reflection mirror 125 and then irradiated onto the storage medium 145. .

The object light is irradiated to the reflection mirror 115 and then reflected and irradiated to the second optical splitter 155 to be separated into the object light of the vertically polarized light and the second reference light of the vertically polarized light. The second reference light of the vertically polarized light is irradiated to the λ / 2 plate 160 and rotated 90 ° to be converted into the second reference light of the horizontally polarized light ↔, and the second reference light of the horizontally polarized light ↔ is reflected on the reflective mirror 130. Reflected and irradiated to the storage medium 145.

On the other hand, the object light of the vertically polarized light separated by the second optical separator 155 is irradiated to the spatial light modulator 140.

In this case, the spatial light modulator 140 is configured as an LCD without a deflection plate as shown in FIGS. 3A and 3B.

As shown in FIGS. 3A and 3B, the spatial light modulator 140 is disposed so that two alignment layers 141 and 142 are spaced apart from each other, and the liquid crystal 143 is arranged to be twisted by 90 ° between the two alignment layers 141 and 142. In the state where no voltage is applied to the alignment layers 141 and 142, the laser beam of the vertically polarized light is twisted by 90 degrees by the liquid crystal 143, converted into the object light of the horizontally polarized light ↔, and passed. When a voltage is applied to the 141 and 142, the liquid crystal 143 vertically passes and the object light of vertical polarization passes as it is.

That is, the spatial light modulator 140 modulates the vertically polarized object light in units of pages of data input from the outside, and optically modulates the vertically polarized object light and the horizontally polarized object light according to the input data. Modulated vertical / horizontal polarization ( Object light is irradiated to the storage medium 145.

Therefore, the storage medium 145 includes an interference fringe caused by interference between the first reference light of vertical polarization and the object light of vertical polarization, and the second reference light of horizontal polarization ↔ and horizontal polarization ↔. The interference fringe by the interference between the object light is recorded.

By this action, when the first reference light of vertically polarized light is irradiated onto the storage medium 145 on which the interference fringe is recorded, the object light of vertically polarized light is reproduced, while the horizontally polarized light ↔ When the second reference light is irradiated, the object light of horizontally polarized light ↔ is reproduced.

4 illustrates an LCD without a deflection plate in which the spatial light modulator 140 is composed of 3 × 3 pixels.

As shown in FIG. 4A, in a state in which the object light of vertical polarization is incident on the spatial light modulator 140, for example, voltages are not applied to the pixels 1, 2, 6, and 8. When the voltage is applied to the pixels 3, 4, 5, 7, and 9, the object light irradiated to the storage medium 145 at pixels 1, 2, 6, and 8 is horizontally polarized (↔ ), And the object light irradiated to the storage medium 145 at pixels 3, 4, 5, 7, and 9 will be object light of vertical polarization.

Thus, when the storage medium 145 is irradiated with the first reference light of the vertically polarized light for reproduction, only the object light of the vertically polarized light is reproduced as shown in FIG. 4B. When the second reference light of the horizontally polarized light ↔ for reproduction is irradiated to the storage medium 145, the image reproduced from the storage medium 145 is only the object light of the horizontally polarized light ↔ as shown in FIG. 4C. Is played.

The object light reproduced by the storage medium 145 by the reference light of vertical or horizontal polarization is imaged by the CCD 150 and converted into an electrical signal, and then processed by the digital signal processor 165 for digital signal processing. The video signal is processed by 170 to be displayed on the monitor 175.

Here, when the object light is reproduced in the storage medium 145 by, for example, a reference light of vertical polarization, pixels 3, 4, 5, 7, and 9 on the monitor 175 may be bright as shown in FIG. 4B. And the rest will be dark. In addition, when the object light is reproduced in the storage medium 145 by the horizontally polarized reference light, pixels 1, 2, 6, and 8 on the monitor 175 will be bright and the rest will be dark as shown in FIG. 4C.

Thus, the examiner can check the recording and playback errors of the volume holographic digital storage system by observing the monitor 175.

As described above, the present invention can check the recording and reproducing error of the hologram data recorded on the storage medium of the volume holographic digital storage system, thereby making it possible to more accurately record and reproduce.

1 is a general configuration diagram of a volume holographic digital storage system,

2 is a detailed block diagram of a volume holographic digital storage system according to a preferred embodiment of the present invention;

3 is an LCD structure diagram applied to a volume holographic digital storage system of the present invention;

4 is a view for explaining an error checking operation of a volume holographic digital storage system having an error checking function according to an exemplary embodiment of the present invention.

<Explanation of symbols for main parts of drawing>

105: light source 110: first optical separator

115, 120, 125, 130: reflection mirror 140: optical modulator

145: storage medium 150: CCD

155: second optical separator 160: lambda / 2 plate

165: digital signal processor 170: video signal processor

175: monitor

Claims (2)

A volume holographic digital storage system for storing interference fringes generated by interfering optically modulated object light and reference light on a page basis of data in a storage medium, comprising: a light source 105 for generating a laser beam of first polarization; A first optical splitter (110) for separating the laser beam of the first polarization into a reference light of the first polarization and an object light of the first polarization; A first reflection mirror 125 reflecting the first reference light of the first polarization; A second reflecting mirror 115 reflecting the object light of the first polarized light; A second optical splitter (155) for separating the object light of the first polarization reflected by the second reflection mirror (115) into a second reference light of the first polarization and an object light of the first polarization; A third reflective mirror 120 reflecting the second reference light of the first polarized light separated by the second optical splitter 155; A λ / 2 plate (160) for rotating the second reference light of the first polarization reflected by the third reflection mirror (120) by 90 ° to convert it into a second reference light of the second polarization; A fourth reflection mirror 130 reflecting the second reference light of the second polarization; The first polarized object light separated by the second optical splitter 155 is modulated in units of pages of data input from the outside, and the first and second polarized object lights and the second polarized light according to the input data are modulated. A spatial light modulator 140 for light modulating the object light; An interference fringe by interference between the first reference light of the first polarization and the object light of the first polarization, and an interference fringe by interference between the second reference light of the second polarization and the object light of the second polarization is recorded, A storage medium 145 that reproduces object light of first polarization when the first reference light of the first polarization is irradiated, and reproduces object light of second polarization when the second reference light of the second polarization is irradiated; A CCD (150) for converting the object light reproduced in the storage medium (145) into an electrical signal; A digital signal processor 165 for digitally processing the output signal of the CCD 150 and outputting an image signal; An image signal processor 170 for performing image signal processing on the digital signal processed image signal; And A volume holographic digital storage system with an error check function comprising a monitor (175). The method of claim 1, wherein the spatial light modulator 140, Volume holographic digital storage system with error checking with LCD without deflection plate.