KR20080107828A - Recording/playback apparatus and method thereof - Google Patents

Abstract

A recording and reproducing apparatus equipped with a proper and simplified optical system in order to improve the recording and reproducing efficiency and a data reproducing method using the apparatus are provided. A recording and reproducing apparatus comprises an optical path adjusting unit(230) which adjusts the path of the light emitted from a light source(210) and irradiates to the specific position of a recording medium, a reflection unit(310) reflecting the light passing through the recording medium to the specific position of the recording medium and generating optical signal for data reproduction, an image sensor unit(240) which receives the reflected light and reproduces the data included in the reflected light, and a light receiving unit(320) which receives the light not passing the recording medium but diffracted and generates monitoring signal.

Description

Recording / playback apparatus and method

1 is a block diagram showing the configuration of a recording / reproducing apparatus that constitutes one embodiment of the present invention.

2 is a block diagram showing an embodiment of an optical system provided in the recording and reproducing apparatus of the present invention together with a recording medium.

3 is a schematic diagram showing an embodiment of an optical path adjusting unit included in the optical system of the present invention together with a recording medium.

4A and 4B are schematic views illustrating a change in the optical path by the first adjusting member in an embodiment of the optical path adjusting unit included in the optical system of FIG. 3.

5 is a perspective view schematically showing an actuator for driving a first adjusting member of the present invention together with the first adjusting member.

6 is a schematic diagram showing an embodiment of a light reflecting unit included in the optical system of the present invention together with a recording medium.

7 is a flowchart schematically showing a data recording method according to the present invention.

8 is a flowchart schematically illustrating a method of reproducing data according to the present invention.

* Description of the symbols for the main parts of the drawings *

100: recording medium 200: front optical system

210: light source 220: light modulator

230: light path adjusting unit 231: first adjusting member

232: second adjusting member 233: actuator

240: image sensor unit 300: rear optical system

310: light reflecting unit 320: light receiving unit

400: signal generator 500: first controller

510: focus servo driver 520: tracking servo driver

530: spindle servo drive 700: second control unit

Background Art [0002] An apparatus for recording and reproducing information on a recording medium such as a compact disc (CD) or digital versatile disk (DVD), which is currently spreading, records information on a tomographic recording surface of a recording medium or reproduces information recorded on a tomographic recording surface. Although the storage capacity can be increased by stacking the recording / reproducing surfaces of the recording medium, the recording / reproducing surface that can be stacked on a single recording medium is about four layers, and thus the storage capacity increases. Due to such a problem of storage capacity limitation, recently, holographic storage technology has attracted attention.

Holography is a technology that can reproduce an optical signal as it is, and stores an interference pattern generated by a signal light having information and a reference light irradiated from an angle different from the signal light in a recording medium or by using diffraction of the stored interference pattern. It is a technique of reproducing information. When holography is used for data recording, the interference pattern can be recorded in three-dimensional space in the thickness direction of the recording medium, so that the storage capacity can be drastically increased. That is, by recording the longitudinal report while changing the incident angle, phase, wavelength, and the like of the reference light, it is possible to record holographic information of several pages with a constant recording capacity. That is, a plurality of pages can be recorded at one position of the recording medium track.

In a reproducing apparatus for reproducing data recorded using holographic technology, in order to reproduce tens or hundreds of pages of data recorded in a predetermined area of the recording medium, the recording medium is rotated at an angle, stopped, and then reflected from the recording medium. The process of photographing reproduction light has to be repeated dozens of times. As described above, when a recording or reproducing method uses a holography technique different from other recording and reproducing methods, an optical system or a recording and reproducing method suitable for this is required.

The present invention reflects the above situation, and an object of the present invention is to provide an optical system suitable for a recording and reproducing apparatus using holography technology and an efficient recording and reproducing method using the same.

An optical apparatus of the present invention for achieving the above object is an optical path adjusting unit for adjusting the path of the light emitted from the light source to irradiate a predetermined position of the recording medium, and the predetermined position of the recording medium for the light transmitted through the recording medium A light reflecting unit for receiving the reflected light, an image sensor unit for reproducing the data contained in the reflected light, and a light receiving unit for receiving a diffracted light that does not pass through the recording medium to generate a signal for monitoring It is configured to include.

Here, the optical path adjusting unit includes a first adjusting member for adjusting an incident angle at which light emitted from the light source is incident on the recording medium, and a second adjusting member for irradiating light having the adjusted angle to the predetermined position on the recording medium. It includes. The first adjusting member may include a tiltable mirror surface to adjust the incident angle, and for this purpose, the optical apparatus may further include an actuator for tilting the mirror surface of the first adjusting member according to a signal generated by the light receiving unit. . The mirror surface of the first adjustment member may be attached to one surface of the actuator. The actuator may tilt the mirror surface of the first adjustment member such that the sum of the signals generated by the light receiver is maximized.

The optical apparatus may further include a signal generator that generates a signal for monitoring by using the sum of the signals generated by the light receiver, and a controller that controls the actuator in response to the monitoring signal. The control unit outputs a signal for controlling the driving of the actuator so that the signal for monitoring is maximized, and outputs a signal for controlling the image sensor unit to capture an image at the position at which the actuator is driven.

 The second adjusting member is composed of a plurality of lenses, irradiating the incident light to a predetermined position of the recording medium, irrespective of the incident angle at which the light having the adjusted angle of incidence enters the second adjusting member.

The light reflecting portion parallelizes the light incident on the first reflecting member with the reflecting member having a reflecting surface reflecting the light transmitted through the recording medium, thereby bringing the light reflected from the reflecting member to a predetermined position of the recording medium. It may be configured to include a reflected light adjusting member for reflecting. The reflected light adjusting member may be composed of a plurality of lenses.

The recording and reproducing apparatus of the present invention includes an optical path adjusting unit for adjusting a path of light emitted from a light source to irradiate a predetermined position of a recording medium, a light reflecting unit reflecting light transmitted through the recording medium to a predetermined position of the recording medium; An image sensor unit for receiving the reflected light and reproducing data contained in the reflected light, a light receiving unit for receiving a diffracted light that does not penetrate the recording medium and generating a signal corresponding to the amount of light, the light receiving unit being generated by the light receiving unit It may include a signal generator for generating a signal for monitoring by using a signal and a control unit for controlling the optical path adjusting unit in accordance with the signal for monitoring generated by the signal generator. The recording and reproducing apparatus may further include an interface unit for receiving a recording or reproducing command from the outside and transmitting the recording or reproducing command to the controller.

The data reproducing method of the present invention includes a light irradiation step of irradiating a reference light to a recording medium on which multiplexed data is recorded, a signal generation step of receiving a reference light diffracted from the recording medium to generate a signal for monitoring, and the generated monitoring. Adjusting the angle of incidence of the reference light incident on the recording medium by controlling the optical path adjusting unit in response to the signal for the optical signal; and using the interference light that is formed while the light passing through the recording medium is reflected and is transmitted through the recording medium again. And reproducing data recorded in the interference light. Here, in the adjusting step, the light path adjusting unit is driven to maximize the signal for monitoring to adjust the incident angle of the reference light. The adjusting step may be performed during data reproduction of the first page of the multiplexed data of the recording medium or data reproduction for each page, and by driving an actuator for tilting a mirror surface provided in the optical path adjusting unit, The angle of incidence can be adjusted. The signal for monitoring is proportional to the light amount of the diffracted light received by the light receiving unit, and can be adjusted to correspond to the incident angle incident upon recording through the above adjustment.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this context, the term " recording medium " in the present specification means any medium in which data is recorded or capable of recording data, and an example may be an optical disc. Incidentally, the term " recording / reproducing device " encompasses a recording device that can only record, a playback device that can only play, and a device that can both record and play.

1 is a block diagram showing the configuration of an embodiment of a recording / playback apparatus according to the present invention together with a recording medium. The recording and reproducing apparatus of the present invention largely comprises an optical system, a signal generator, a controller, and a servo driver. In the present specification, the optical system will be divided into a front optical system and a rear optical system based on a recording medium. However, the front optical system and the rear optical system are for convenience of description and are not limited to the terms.

2 shows a configuration of a specific embodiment of the optical system included in the recording and reproducing apparatus of the present invention. As shown, the front optical system 200 includes a light source 210, a light path adjusting unit 230, a light modulating unit 220, an image sensor unit 240, and other optical elements. The back optical system 300 includes a light receiving unit 320 and a light reflecting unit 310. Here, each configuration will be described in detail with reference to the drawings.

The light source 210 is composed of a gas laser, a solid state laser, a semiconductor laser, a semiconductor diode, or the like that generates light having a very high coherence, for example, a laser beam. A collimation lens may be disposed at the output end of the light source 210 to collect the light output from the light source 210 so as not to be dispersed.

The light output from the light source 210 passes through at least one optical element, such as a separation compound, for path change and separation. In this embodiment, an example configured to penetrate one separation and synthesis part is shown. The separation composition may be composed of one or more transparent substrates and one or more grating layers diffracting light, or may be composed of a mirror that reflects a part of the light and transmits the rest. Through this, the incident light is divided into a signal light and a reference light. For example, the light may be configured to partially transmit and partially reflect incident light depending on the polarization direction.

The light modulating unit 220 is a portion which includes a signal pattern (data pattern) in the signal light when recording data. For example, the optical modulator 15 may be configured to include binary data represented by a black and white dot pattern in the signal light irradiated to the recording medium 100.

The optical path adjusting unit 230 adjusts the incident angle, direction, wavelength, phase, and the like of incident reference light to irradiate the recording medium 100. Specifically, the optical path adjusting unit 230 multiplexes the angles of the reference light in order to record or record data on the recording medium 100 using holographic technology. In this case, the multiplexing refers to recording or reproducing data while continuously changing an incident angle of the reference light radiated to a predetermined region of the recording medium 100. This method can store hundreds to thousands of holograms organized in page units of binary data in the same location. In other words, by recording or reproducing a lot of data on the recording medium 100 in units of pages, data can be recorded or reproduced with high storage density.

3, 4A, and 4B schematically illustrate the configuration of a specific embodiment of the optical path adjusting unit 230. As shown, the optical path adjusting unit 230 includes a first adjusting member 231 having a reflecting surface that can rotate or move to reflect the reference light to adjust the incident angle or direction of the reference light, and the incident light is adjusted. And a second adjusting member 232 for irradiating a predetermined position of the recording medium.

In detail, in the present exemplary embodiment, the first adjusting member 231 has a reflective surface capable of tilting, and the first adjusting member 231 is incident on the second adjusting member as the reflective surface of the first adjusting member 231 is tilted. Adjust so that the incident angle of light changes. In this case, the first adjusting member 231 may be attached to one surface of the actuator 233 for driving the first adjusting member 231, which is illustrated in FIG. 5. In this embodiment, the first adjusting member 231 can be tilted in a simple manner by driving the actuator 233 in response to a monitoring signal to be described later. Such a configuration has a side of simplifying the optical system.

The second adjusting member 232 irradiates the light having the adjusted angle of incidence equally to a specific portion of the recording medium regardless of the angle of incidence. As shown in FIGS. 4A and 4B, the light transmitted through the second adjustment member 232 is recorded even when the angle incident on the second adjustment member 232 is changed by the tilt of the first adjustment member 231. The same position Y of the recording side L0 included in the medium is irradiated. Through this, only the angle of incidence at the same position Y is changed and light can be irradiated to the recording medium. Here, the second adjusting member 232 includes two lenses, a first lens 232a and a second lens 232b as shown, or the first lens 232a and the second lens 232b. Various modifications are possible, such as having two lenses each including four lenses.

The light reflecting portion 310 of FIG. 2 is a portion that reflects light transmitted through the recording medium. Specifically, a specific embodiment of the light reflecting unit 310 will be described with reference to FIG. 5. In the present exemplary embodiment, the fraud light reflection unit 310 includes a reflection light adjusting member 311 and a reflection member 312. The reflecting member 312 has a reflecting surface that reflects light transmitted through the recording medium, and is a portion that reflects light. The reflected light adjusting member 311 is a portion for paralleling the light incident on the reflector member 312. Through this, the reflected light adjusting member 311 is a portion to be reflected in the same path as the light path transmitted through the light reflected by the reflecting member 312. To this end, the reflected light adjusting member 311 may be composed of a plurality of lenses.

The image sensor unit 240 is a portion for capturing a data image by using the light reflected by the light reflecting unit 310. For example, the image sensor unit 240 may be configured to capture a data image when the amount of light reflected is maximized. To this end, the image sensor unit 240 includes the image sensor composed of a semiconductor imaging device such as a charge-coupled device (CCD). Here, the separation unit may be further configured to configure the reflected light to enter the image sensor unit.

The light receiving unit 320 is a portion that receives the light diffracted by the recording medium 100 when it enters the recording medium 100 through the optical path adjusting unit 230. That is, the light reflected by the light reflecting unit 310 and received by the image sensor unit 240 is separated and received by the light diffracted by the recording medium 100. The light receiving unit 320 is configured as a light receiving element for generating an optical signal corresponding to the amount of light received. For example, the light receiving unit 320 may be composed of four light receiving elements A, B, C, and D or one light receiving element.

The signal generator 400 of FIG. 1 generates a signal for monitoring using the signal output from the light receiver 320. For example, a recording / reproducing signal (RF signal) is generated, a focus error signal (hereinafter referred to as FE), a tracking error signal (hereinafter referred to as TE), and a rotation error signal (rotation error signal) And a signal for servo control such as RE). In the present embodiment, the signal for monitoring may use a recording / reproducing signal (RF signal) proportional to the amount of light received by the light receiving unit 320. Here, the recording and reproducing signal (RF signal) is proportional to the amount of light received by the light receiving unit 320 and can be calculated as follows.

Here, ab, c, d means a photoelectrically converted signal output from each of the light receiving elements A, B, C, and D.

The first controller 500 of FIG. 1 is a part that outputs a control signal for controlling the driver by using the signal generated by the signal generator 400. For example, the first control unit 500 may control the light path adjusting unit to control the light path adjusting unit 230 of the front optical system 200 in response to the monitoring signal generated by the signal generating unit 400. Output to actuator 233. The control signal is output to the focus servo driver 510, the tracking servo driver 520, and the spindle servo driver 530 in correspondence with the focus error signal FE, the tracking error signal TE, the rotation error signal RF, and the like. do.

The focus servo driver 510 and the tracking servo driver 520 drive the optical path adjusting unit 230 or the recording medium 100 of the front optical system 600 to change the position at which light is irradiated onto the recording medium 100. The spindle servo driver 530 drives the spindle motor to change the rotational speed of the recording medium 100.

The apparatus may further include a second controller 700 which receives an external recording or reproducing command and transmits the same to the recording and reproducing unit 600 through an interface. In this case, the interface may typically use ATAPI (Advanced Technology Attached Packet Interface, 110). Here, the ATAPI 110 is an interface standard between a recording / playback unit such as a CD or DVD drive and a host, and is a standard proposed to transmit data decoded by a drive to a host. It converts and transmits the protocol.

The following describes the recording method and the reproduction method using the recording and reproducing apparatus of the present invention in detail. First, a method of recording data on the recording medium 100 will be described in detail with reference to FIG. The light emitted from the light source 210 is separated into signal light and reference light and irradiated to the recording medium 100 (S11). The signal light is a light in which a data signal is stored, and the light modulator 220 records binary data in the signal light in various ways. The reference light is irradiated to the recording medium 100 while the incident angle is changed by the optical path adjusting unit 230 (S12). As the angle of incidence is changed, a plurality of pages of data images may be superimposed on one area of the recording medium 100 (S13). In this case, the optical path adjusting unit 230 may be controlled to change the incident angle by the first control unit 500.

In order to reproduce the data of the recording medium 100 on which the superimposed images are recorded, only the reference light should be irradiated to the recording medium 100, and the incident angle of the reference light should match the incident angle at the time of recording. Playback is possible. In this case, the term "reproducing" broadly refers to an operation of reading stored data, and also includes execution of a stored computer program, outputting and copying of stored data, and the like.

In the case of reproducing data stored in the recording medium 100, first, the first control unit 500 positions the optical path adjusting unit 230 to a point capable of reproducing data. That is, the first controller 500 moves to the position where the reference light can be irradiated to the corresponding area of the recording medium 100 based on the page address of the stored data. In particular, the first adjusting member 231 of the optical path adjusting unit 230 is located at a position where the data of the first page or the last page can be read among the data (data images) of several pages stored in the corresponding area of the recording medium 100. And it is preferable to position the second adjustment member 232. There are many ways to find out where the data on the first or last page can be read. For example, an alignment mark photographed through the image sensor unit 240 may be used before reproducing the data of the first page or the last page. The alignment mark is generated when data is recorded and is displayed on a border or a specific area of the stored data image. The first controller 500 determines whether the angle of the first adjusting member 231 of the optical path adjusting unit 230 is correct based on the alignment mark, and whether the image sensor 240 is frozen in the data page. It can be determined whether or not.

An embodiment of a method of reproducing data at the position will be described in detail with reference to FIG. 8. The light output from the light source 210 is separated into a signal light and a reference light, and since the signal light is not required at the time of data reproduction, the light transmitted to the light modulator 220 is not irradiated to the recording medium 100. Therefore, the reference light is irradiated to the recording medium 100 for reproduction (S21). If necessary, the signal light may be used during reproduction.

When the reference light starts to be irradiated to the recording medium 100 through the optical path adjusting unit 230, the first adjusting member 231 of the optical path adjusting unit 230 is in response to a command of the first control unit 500. The incident angle of the reference light may be continuously or intermittently changed from the minimum incident angle to the maximum incident angle or from the maximum incident angle to the minimum incident angle. Here, the minimum incident angle is an incident angle of the reference light for reading the first page data, and the maximum incident angle corresponds to an incident angle of the reference light for reading the last page data. The angle of incidence is adjusted to be (S22). For example, the reference light is irradiated onto the recording medium 100 while changing the incident angle incident on the recording medium 100. Specifically, the first adjusting member 231 is tilted by driving the actuator 233 in response to the monitoring signal. At this time, the first adjustment member 231 is tilted in the direction in which the recording / reproducing signal RF for monitoring generated has the maximum value. The recording / reproducing signal RF having the highest diffraction efficiency is detected at every position of the recorded data on the recording medium 100 on which the multiplexed data is recorded or on the first page constituting each book. The actuator 233 is driven to position the reflective surface of the first adjusting member 231. Through this, an incident angle for reproducing the data can be controlled without requiring a separate device such as an image sensor. In relation to this, a book means an area of the recording medium 100 in which information is superimposed and recorded by a multiplexing method.

The reference light with the adjusted angle of incidence is irradiated onto the recording medium 100 to have the same angle of incidence as in data recording (S23). A part of the reference light passes through the recording medium 100, is reflected by the light reflecting unit 310, and then reenters the recording medium 100. The reflected light forms the interference light while transmitting the recording medium 100 again, and records the recorded data in the interference light. The interference light is received by the image sensor unit 240 to reproduce data. Here, the captured data can be reproduced without error by capturing an image at a position where the recording and reproducing signal RF has the largest value. Here, a part of the reference light incident on the recording medium 100 is diffracted and received by the light receiving unit 320 to form a recording / playback signal RF for monitoring driving the actuator 233 to be used for feedback control (S24). ).

In the recording and reproducing apparatus and the recording and reproducing method according to the present invention as described in detail above, the following effects can be expected.

That is, there is an advantage in providing a simplified optical system suitable for a recording and reproducing apparatus using holography technology.

In addition, there is an advantage of providing an efficient recording and reproducing method in the recording and reproducing process using the holography technology.

Claims (26)

An optical path adjusting unit which adjusts a path of light emitted from the light source and irradiates a predetermined position on the recording medium; A light reflecting portion that reflects light passing through the recording medium to a predetermined position of the recording medium; An image sensor unit which receives the reflected light and reproduces the data contained in the reflected light; And a light receiving unit which does not transmit the recording medium and receives diffracted light to generate a signal for monitoring. The method of claim 1, wherein the optical path adjusting unit, A first adjusting member for adjusting an incident angle at which light emitted from the light source is incident on the recording medium; And a second adjusting member for irradiating the light having the adjusted angle of incidence to a predetermined position of the recording medium. The method of claim 2, wherein the first adjustment member, And a tiltable mirror surface to adjust the angle of incidence. The optical device of claim 3, wherein the optical device is And an actuator configured to tilt the mirror surface of the first adjusting member in response to a signal generated by the light receiving unit. The method of claim 3, And a mirror surface of the first adjustment member is attached to one surface of the actuator. The method of claim 3, wherein the actuator, And tilting the mirror surface of the first adjusting member so that the sum of the signals generated by the light receiving portion is maximized. The optical device of claim 6, wherein A signal generator which generates a signal for monitoring by using the sum of the signals generated by the light receiver; And a controller for controlling the actuator in response to the monitoring signal. The method of claim 7, wherein the control unit, And outputting a signal for controlling driving of the actuator so that the signal for monitoring is maximized, and outputting a signal for controlling the image sensor unit to capture an image at the position at which the actuator is driven. The method of claim 2, wherein the second adjustment member, An optical apparatus, comprising: a plurality of lenses, irradiating the incident light to a predetermined position of the recording medium, irrespective of the incident angle at which the light having the adjusted angle of incidence enters the second adjusting member. The method of claim 1, wherein the light reflecting unit, A reflecting member having a reflecting surface that reflects light transmitted through the recording medium; And a reflected light adjusting member reflecting the light reflected from the reflecting member to a predetermined position of the recording medium by parallelizing the light incident to the first reflecting member. The method of claim 10, wherein the reflected light adjusting member, Optical device, characterized in that composed of a plurality of lenses. An optical path adjusting unit which adjusts a path of light emitted from the light source and irradiates a predetermined position on the recording medium; A light reflecting portion that reflects light passing through the recording medium to a predetermined position of the recording medium; An image sensor unit which receives the reflected light and reproduces the data contained in the reflected light; A light receiving unit which receives the diffracted light without passing through the recording medium and generates a signal corresponding to the amount of light; A signal generator for generating a signal for monitoring by using the signal generated by the light receiver; And And a control unit for controlling the optical path adjusting unit in accordance with a signal for monitoring generated by the signal generating unit. The optical path adjusting unit of claim 12, A first adjusting member for adjusting an incident angle at which light emitted from the light source is incident on the recording medium; And a second adjusting member for irradiating the light having the adjusted angle of incidence to a predetermined position of the recording medium. The method of claim 13, wherein the first adjustment member, And a tiltable mirror surface to adjust the incident angle. The optical device of claim 12, wherein the optical device is And an actuator for tilting the mirror surface of the first adjusting member in response to a signal generated by the light receiving unit. The method of claim 15, wherein the actuator, And tilting the mirror surface of the first adjusting member so that the sum of the signals generated by the light receiving portion is maximum. The method of claim 16, wherein the control unit, And a signal for controlling the driving of the actuator so that the signal for monitoring is maximized, and a signal for controlling the image sensor unit to capture an image at the position at which the actuator is driven. The method of claim 12, wherein the second adjustment member, And a plurality of lenses, wherein the incident light is irradiated to the predetermined position of the recording medium irrespective of the incident angle of the incident light to the second adjusting member. The method of claim 12, wherein the light reflecting unit, A reflecting member having a reflecting surface that reflects light transmitted through the recording medium; And a reflected light adjusting member reflecting the light reflected from the reflecting member to a predetermined position of the recording medium by parallelizing the light incident on the first reflecting member. The recording and reproducing apparatus according to claim 12, And an interface unit for receiving a recording or reproducing command from the outside and transmitting the recording or reproducing command to the control unit. A light irradiation step of irradiating the reference light onto the recording medium on which the multiplexed data is recorded; A signal generation step of receiving a reference light diffracted by the recording medium to generate a signal for monitoring; An adjusting step of controlling an optical path adjusting unit corresponding to the generated monitoring signal to adjust an incident angle of the reference light incident on the recording medium; And a reproducing step of reproducing the data recorded in the interfering light by using the interfering light formed while the light passing through the recording medium is reflected and transmitted through the recording medium again. The method of claim 21, wherein the adjusting step, And controlling the incident angle of the reference light by driving the optical path adjusting unit to maximize the signal for monitoring. The method of claim 22, wherein the adjusting step, And data reproduction for each page or data reproduction for each page of the multiplexed data of the recording medium. The method of claim 21, wherein the adjusting step, And controlling an incident angle of the reference light by driving an actuator for tilting a mirror surface of the optical path adjusting unit. The method of claim 21, wherein the signal for monitoring, And a proportion of light of diffracted light received by the light receiving unit. The method of claim 21, wherein the reference light, A data reproducing method, characterized in that it is adjusted to correspond to an incident angle incident upon recording.

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