KR20070008275A - Hologram play & storage system consisting of multiple ccd - Google Patents

Abstract

A hologram reproducing apparatus including a plurality of detection elements and a storing device including the same are provided to obtain a sufficient reading speed by using low-priced CCDs(Charge Coupled Devices) because a reading speed can be increased by the number of composed CCDs although a CCD having low performance is used. Optical splitters(402-1~402-n) split a laser into a reference beam and an object beam. A reference beam reflective mirror(6) reflects the reference beam. At least one or more detection elements(401-1~401-n) receive the reference beam, and detect a signal in which data are reproduced.

Description

Hologram reproducing apparatus including a plurality of detection elements and a storage device including the same {Hologram Play & Storage System consisting of multiple CCD}

1A is a conventional hologram storage device comprising fixed media.

1B illustrates a conventional hologram storage device comprising rotating media.

2A and 2B illustrate changes in diffraction patterns when reference light is incident in different directions

3 is a conventional hologram reproducing apparatus.

4 is a hologram reproducing apparatus including a plurality of detection elements according to an embodiment of the present invention.

{Description of Signs of Major Parts of Drawings}

1: primitive light source 2: light splitter

3: object light reflection mirror 4: spatial light modulator

6: reference light reflecting mirror 7: optical media

9: object light 10: reference light

400, 401-1 to 401-n: CCD 402-1 to 402-n: Photodetector

The present invention relates to a hologram reproducing apparatus and a storage device including the same, and in particular, in a three-dimensional hologram drive, which is a mass storage device, an additional optical splitter is provided on a reproducing optical path for high-speed response. A hologram storage device is provided with two or more detectors to read sequentially.

Recently, the multimedia industry is developing into a highly technology-intensive industry in which various industries such as home appliances, computers, communication, video, and broadcasting are converged. To meet this multimedia industry environment, a new information environment is needed. In other words, as the amount of information is enormous, ultra large capacity, ultra high speed, and ultra small size of information storage media are required. For example, in order to commercialize video-on-demand of multimedia information communication, a video server requires 10 ³ Tb or more and a data transfer rate of 1 Gb / sec or more.

However, the current semiconductor memory, magnet-optical disc (MOD) and compact disc (CD) have a technical and economic limitation in this information storage process, and a new generation of ultra-large capacity information storage devices is urgently needed. Currently, CD memory has a capacity of 640MB (1 hour 40 minutes of music or more than 300,000 pages of double-sided documents), but hundreds to tens of thousands in hospitals, law, companies, government agencies, libraries, etc. He's using an expensive Jukebox, which stacks disks and accesses them with a robotic arm.

Conventional CD / DVD storage has been a two-dimensional storage method for storing information on one side of media using beam spots collected from a laser light source. In this case, the data storage capacity was increased by adjusting the pitch interval between tracks or increasing the number of layers. However, the reduction of the pitch interval and the increase of the layers have physical limitations. It becomes impossible.

Therefore, the hologram storage method, which is a three-dimensional three-dimensional storage method introduced to overcome this problem, can record information inside the storage medium by using the diffraction and interference effects of light, which is several tens to hundreds compared to CD / DVD. The ship's storage capacity can be secured.

The hologram refers to reproducing or storing the same light waves used when being stored. The hologram memory stores and reproduces two-dimensional light patterns. This method of storage can be read separately from each other even if they are stored in a superimposed manner by an appropriate multiplexing technique. Since the two-dimensional image is reproduced at the same time, the read-by-page unit realizes a large capacity parallel access memory system. Implementation is possible.

1 illustrates a basic structure of a conventional hologram memory system.

The laser 1 is split into a reference beam 10 and an object beam 9 to which a signal is to be carried by a beam splitter 2. The object light is modulated into a two-dimensional pattern by desired input data while passing through a spatial light modulator (SLM) 4. This light interferes with the reference light 10 in the media 7 of the photorefractive material to store information. When reading the information, only the reference light 10 is irradiated to the photorefractive material. Then, the signal light carrying the original information is reproduced and incident on a detector array 8 such as a CCD (Charge Coupled Device).

2 is a block diagram of a disk rotating hologram storage device. If FIG. 1 is a hologram storage device using fixed media, the hologram storage device of FIG. 2 is rotated by forming a media similar to an optical disc media of a general CD / DVD, and data is sequentially stored along a track. . However, the media of the disk rotating hologram storage device do not rotate at high speed like a normal CD / DVD. ) Is stored and rotated in stepping fashion.

2A and 2B illustrate a method of storing pages in media. Since different diffraction patterns appear according to the input direction of the reference light, it is possible to store several pages in one page.

As a technical method of increasing storage capacity in relation to a hologram drive, an angular multiplexing, a phase multiplexing, a wavelength multiplexing method, and the like have been introduced.

In the angular multiplexing method, the disc incident angle of the reference light is adjusted to improve the storage density of the media, so that data recorded at a specific angle can be reproduced only by irradiating the laser again at that specific angle.

The section in which the angle of the reference light can be selected so that data can be recorded and reproduced is called each selectivity. Currently, a method in which the mirror of the reference light is rotated and overlapped in only one direction is selected. As described above, the 3D hologram storage device includes a light splitter that generates light, a light splitter that divides the light into two beams having different paths, a storage unit that collects and stores the divided beams in one place, and collects light to reproduce the stored data. It is divided into condensing part.

In order to reproduce the light, the light must be irradiated at the same angle as the reference light used for initial data storage. In this case, this is called separately reproduced light. When the reproduced light passes through the recorded medium, it is formed in a light condensing unit such as a CCD in a state where information is stored, thereby enabling reproduction.

In the case of the conventional hologram storage device, one CCD is placed in the condensing unit to read data, and the reading speed depends on the performance of the CCD.

However, the frame bit rate of the CCD is lower than the speed of the reproduction light, and the overall speed is lowered. To solve this problem, a large number of noise components are detected due to the low resolution. However, a condensing sensor such as a CMOS having a high frame rate is used.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide a hologram reproducing and storage device which can ensure a sufficient reading speed even when using a low performance detection element.

In order to achieve the above object, the hologram reproducing apparatus of the present invention includes a light splitter for dividing a laser into a reference light and an object light, a reference light reflecting mirror reflecting the reference light, and a reference light to detect a signal from which data is reproduced. At least one detection element is included.

In the present invention, an optical splitter for converting an optical path of a signal in which the data is reproduced is provided between the optical media and the detection element, and when the number of the detection elements is N, the optical splitter is preferably provided with N-1. Do.

In the present invention, the optical path is preferably converted to a right angle.

In the present invention, it is preferable that the detection element sequentially detects a signal in which data is reproduced, and detects a signal in which data is reproduced at regular intervals.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In adding reference numerals to components of the following drawings, it is determined that the same components have the same reference numerals as much as possible even if displayed on different drawings, and it is determined that they may unnecessarily obscure the subject matter of the present invention. Detailed descriptions of well-known functions and configurations will be omitted.

3 is a block diagram of a general reproducing hologram reproducing apparatus.

In the above embodiment, the hologram reproducing apparatus includes a light splitter 2, a reference light reflecting mirror 6, an optical medium 7 on which data is stored, and a detection element 400 for detecting data.

The above embodiment briefly shows the configuration of a hologram reproducing apparatus dedicated to reproduction only.

Referring to FIG. 3, the incident laser 1 is split into the reference light 10 and the object light in the light splitter 2. In the case of the hologram reproducing apparatus, since the reproduction is dedicated, the object light necessary for recording data on the optical media 7 is not necessary. Therefore, only the reference light 10 is divided and the divided reference light 10 is incident on the optical media 7 by the reference light reflecting mirror 6. The incident reference light 10 reproduces data by interfering with the diffraction pattern recorded on the optical media 7, and the reproduced data is detected using the detection element 400, generally a CCD camera.

Commercially available CCD cameras range from ultra high speed systems of 40,000 frames per second (128 x 128 pixels per frame) to low speed systems of 7 frames per second (2048 x 2048 pixels per frame). Recently, high speed and high resolution CCD image sensor systems with 1,000 frames per second (1024 x 1024 pixels per frame) have been developed.

CCD cameras are an important part of hologram storage, and the number of bits in the input data page, the size and spacing of data pixels are all determined by the pixel size of the CCD chip. The CCD array should be well matched with the data input element LC-SLM in terms of the number of pixels as well as the pixel size and pixel pitch in the x and y directions. The CCD array also determines the ultimate noise limit for detecting weak diffraction patterns without bit errors with limited laser power. LC-SLM, which is used as a portable TV, processes 320 x 240 pixels of input image data into video frames. In high-speed ferroelectric SLMs, 128 x 128 pixel image data is processed into video frames. Ferroelectric high-speed SLMs can process 128 x 128 pixel images at 200 kHz and currently support 256 x 256 pixel images.

In addition, the active matrix SLM for high-resolution projection displays can handle 2048 x 2048 pixels with 8-bit gray levels at 80 frames per second (2.7 Gbit / s) and binary at 1,000 frames per second (4 Gbit / s). Up to operation is possible.

As such, the role of the detection element in the hologram rejuvenation device is important and the performance is being improved.

4 is a block diagram of a hologram reproducing apparatus including a plurality of detection elements according to an exemplary embodiment of the present invention.

The above embodiment schematically shows a hologram reproducing apparatus having a plurality of detection elements 400,401.

Referring to FIG. 4, N detection elements 401-1 to 401-n are further provided between the optical media 7 and the detection element 400 provided in the existing hologram reproducing apparatus. Preferably, the detection elements 401-1 to 401-n are CCDs. The CCD camera has respective light splitters 402-1 to 402-n.

The data reproduced is input to the CCD cameras 401-1 to 401-n through the optical splitters 402-1 to 402-n for converting the optical paths. The provided CCD cameras 401-1 to 401-n need not be provided with cameras of the highest performance. The CCD cameras 401-1 to 401-n operate sequentially at regular time intervals. In other words, if a screen detection of 100 frames per second is required, a CCD camera that recognizes 100 frames per second should be used. However, in the present invention, the CCD camera recognizes only 10 frames per second. It can have the same recognition effect.

As described above, the case of implementing the present invention using ten CCD cameras 400 and 401-1 to 401-9 will be described.

When 10 CCD cameras 400 and 401-1 to 401-9 are provided, the nine CCD cameras 401-1 to 401-9 are positioned to enter a direction perpendicular to the direction in which a signal including data travels. The other 400 is located in the direction in which the signal is incident. The nine CCD cameras 401-1 to 401-9 have light splitters 402-1 to 402-9 for this purpose because the optical path is changed. That is, when N CCD cameras are provided, N-1 light splitters are required. Therefore, when the ten CCD cameras 400 and 401-1 to 401-9 are provided, nine light splitters 401-1 to 401-9 are required.

The CCD camera thus constructed is controlled to operate sequentially. In other words, the signal is transmitted to the control unit to be sequentially recognized at a predetermined time interval. That is, if 100 frames are required in 1 second, 401-1, the first CCD camera, recognizes the signal in 1/100 second, and 401-2, the second CCD camera in 2/100 second. Make this aware. In this order, the last CCD camera recognizes the signal in 10/100 seconds. If this process is repeated for 1 second, one CCD camera can process only 10 frames but can process 100 frames as a whole. Such sequentially input data may be transmitted to and processed by the controller in order.

That is, the approach time allocated to the CCD is adjusted according to the rotation stage step of the reference light reflecting mirror for adjusting the angle of the reference light. This method has the advantage that the reading speed is increased by the number of configured CCD cameras, even if a low-performance CCD is used, unlike a method in which a conventional CCD camera is configured in one and the reading speed is determined by the CCD performance.

As described above, it has been described with reference to the preferred embodiment of the present invention, but those skilled in the art various modifications and changes of the present invention without departing from the spirit and scope of the present invention described in the claims below I can understand that you can.

As described above, according to the present invention, the read speed is increased by the number of configured CCDs even when a low-performance CCD is used, unlike a conventional method in which the reading speed depends on the performance of the CCD when the hologram storage device is regenerated. Therefore, a low cost CCD can be used to ensure sufficient read speed.

Claims (7)

A light splitter for dividing the laser into reference light and object light; A reference light reflecting mirror reflecting the reference light; And And at least one detection element which receives the reference light and detects a signal in which data is reproduced. The hologram reproducing apparatus according to claim 1, further comprising an optical splitter for converting an optical path of a signal in which the data is reproduced. The hologram reproducing apparatus according to claim 2, wherein when the number of detection elements is N, the light splitter is provided with N-1. The hologram reproducing apparatus according to claim 2, wherein the optical path is converted to a right angle. The hologram reproducing apparatus according to claim 1, wherein the detection element sequentially detects a signal in which data is reproduced. The hologram reproducing apparatus according to claim 5, wherein the detection element detects a signal in which data is reproduced at regular time intervals. A hologram storage device comprising the playback device of any one of claims 1 to 6.

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