KR20080010914A - Method and apparatus for recording/replaying data, and recording medium - Google Patents

Abstract

A method and an apparatus for recording/reproducing data, and a recording medium are provided to obtain precise time of image acquisition based on control information recorded in the data image while the incident angle of reference beam is successively changing, and compensate the deviation of incident angle of reference beam caused by deformation or tilting of the recording medium based on the control information. A method for recording/reproducing data comprises the steps of: projecting beam on a predetermined area of a recording medium while changing incident angle of the beam from a minimum angle for reproduction of the first data in the recording medium to a maximum angle for reproduction of the last data(S41,S42); detecting control information from the beam diffracted by the recording medium by acquiring data images including a user data area and a control information area from the beam and detecting the control information recorded in the control information area(S43); and reading data recorded in the recording medium based on the detected control information(S44).

Description

Method and apparatus for recording / reproducing data, and recording medium {Method and apparatus for recording / replaying data, and recording medium}

1 is a diagram showing the configuration of a data recording / reproducing apparatus of the present invention;

2 is a diagram showing a data image of the present invention;

3 is a flowchart showing a data recording method of the present invention;

4 is a flowchart showing a data reproducing method of the present invention;

5 is a view showing the intensity of light reflected from the control mark according to the incident angle of the reference light.

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

11 light source 13,16 light splitting

14: reference light control unit 15: light modulator

17: memory 18: image sensor

19: light detector 20: control unit

100: recording medium

The present invention relates to an optical recording / reproducing apparatus, and more particularly, to a method and apparatus for recording / reproducing data on a recording medium using holography.

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. The storage capacity can be increased by stacking the recording / reproducing surfaces of the recording medium. However, since the recording / reproducing surface that can be stacked on a single recording medium is about four layers, 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 on a recording medium or by using diffraction of the stored interference pattern. It is a technology that can reproduce information. By using the holographic storage technology, since interference patterns can be superimposed in three-dimensional (spatial) directions in the thickness direction of the recording medium, the storage capacity can be dramatically increased. In other words, when information is recorded while changing the incident angle, phase, wavelength, and the like of the reference light, it is possible to record several pieces of holography information at a constant capacity. Therefore, it is possible to implement a super capacity recording medium. In addition, since the signal light and the recording light can be irradiated to the recording medium using the optical splitter and the single objective lens, the optical recording / reproducing apparatus can be miniaturized.

However, in the conventional optical recording / reproducing apparatus using holography, when the incident angle of the reference light is not correct, interference between data to be recorded or reproduced occurs. For example, when the data is reproduced, the incident angle of the reference light should be the same as the incident angle at the time of recording. If the incident angle of the reference light is not the same, the recorded data cannot be accurately restored.

In the case of a conventional optical disc, information necessary for focusing control (servo), tracking control, etc. of light can be recorded and used in a predetermined area of the recording layer of the optical disc. However, in the case of a recording medium using holography, information necessary for servo, such as control of the incident angle of the reference light, cannot be recorded in a predetermined area. In particular, the point in time at which page-based data is taken or the angle of incidence of the reference light varies from page to page. Therefore, it is essential to easily and quickly obtain the servo information for accurate restoration of data.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned disadvantages of the prior arts, and an object of the present invention is to provide a data recording / reproducing method and apparatus and a recording medium capable of increasing the accuracy of data restoration.

A data reproducing method of the present invention for achieving the above object comprises the steps of irradiating light to a predetermined region of the recording medium while changing the incident angle; Detecting control information from the light diffracted by the recording medium; Reading data recorded on the recording medium on the basis of the detected control information.

Detecting control information from the light diffracted by the recording medium includes: capturing a data image from the light including a user data area and a control information area; Detecting the control information recorded in the control information area. Here, the control information may include a mark indicating whether the data image is left and right eccentric, a mark indicating whether the data image is eccentric, an address information of the data image, a mark for distinguishing an area of the recording medium, It includes at least one of the data determination reference value.

The reading of the data recorded on the recording medium on the basis of the detected control information includes determining the reading time point of the data recorded on the recording medium on the basis of the control information.

A data reproducing apparatus of the present invention comprises: a light adjusting unit for irradiating light to a predetermined region of a recording medium while changing an incident angle; And a light detector for detecting control information from the light diffracted by the recording medium and reading data recorded on the recording medium based on the detected control information.

The data recording method of the present invention comprises the steps of: generating a first light including user data and control information; Irradiating the first light to a predetermined area of the recording medium and irradiating a second light to the predetermined area of the recording medium while changing the incident angle to record the user data and the control information in the predetermined area of the recording medium. Wow; Storing the address of the recorded user data and the incident angle of the second light.

In the recording of the user data and the control information in a predetermined area of the recording medium, the user data and the control information in the form of a data image including a user data area and a control information area. To record.

In addition, in the storing of the address of the recorded user data and the incident angle of the second light, the address of the user data and the incident angle of the second light are stored in the recording medium or the memory.

A data recording apparatus of the present invention includes: a first optical output unit for irradiating a predetermined region of a recording medium with a first light including user data and control information; A second light output unit for irradiating a second light while varying an angle of incidence in a predetermined region of the recording medium to which the first light is irradiated; And a controller configured to output an address of the user data and an incident angle of the second light.

A recording medium of the present invention for recording a plurality of data images comprises: a user data area located in a predetermined area of the data image, in which user data is recorded; And a control information area located in another area of the data image except for the user data area, in which control information for controlling reproduction of the data image is recorded.

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

Fig. 1 briefly shows an example of a data recording / reproducing apparatus according to the present invention, and shows only the configuration necessary to explain the technical gist of the present invention without omitting general elements. As shown in FIG. 1, the data recording / reproducing apparatus of the present invention includes a light source unit 11, first and second light splitters 13 and 16, a reference light adjuster 14, a light modulator 15, and a memory ( 17) and an image sensor 18.

The light source unit 11 is composed of a gas laser, a solid laser, a semiconductor laser, a semiconductor diode, or the like, which generates light having a very high coherence, for example, a laser beam. A collimation lens may be disposed at the output end side of the light source unit 11 to collect the light output from the light source unit 11 so as not to be dispersed.

The first light splitter 13 receives the light output from the light source 11 and divides the light into a signal light and a reference light. The first light splitter 13 may be composed of one or more transparent substrates and one or more grating layers diffracting light, or may be configured as mirrors that reflect a part of the light and pass the rest.

The optical modulator 15 includes a data pattern in the signal light output from the first optical splitter 13 when recording data, and then irradiates the signal light to the recording medium 100. For example, the optical modulator 15 includes binary data represented by a black and white dot pattern in the signal light irradiated to the recording medium 100. Accordingly, binary data is included in a user data region of the data image recorded on the recording medium 100. The light modulator 15 also records various marks outside the user data area of the data image. The mark will be described later.

The reference light adjusting unit 14 receives the reference light from the second light splitting unit 16 and adjusts the angle of incidence, direction, wavelength, phase, and the like of the reference light according to a command of the control unit 20 to record the reference light. The medium 100 is irradiated. The reference light adjusting unit 14 multiplexes the angles of the reference light to record or reproduce data. In this case, the multiplexing refers to recording or reproducing data while continuously changing an incident angle of the reference light irradiated to a predetermined area 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. By recording or reproducing a lot of data on the recording medium 100 in units of pages, it is possible to record or reproduce data with a high storage density. Here, a collection of hundreds to thousands of data images superimposed in a predetermined area is called a book. The reference light adjusting unit 14 may include a mirror reflecting the reference light and a mirror driving unit rotating or moving the mirror according to a command of the controller 20 to adjust the incident angle or direction of the reference light. Include.

When the data stored in the recording medium 100 is reproduced, the reference light irradiated by the reference light adjusting unit 14 is diffracted by an interference fringe of the data recorded on the recording medium 100. Thus, the reference light that passes through or is reflected by the recording medium 100 includes a data image recorded on the recording medium 100.

The controller 20 records various control information in the form of a mark in the data image recorded on the recording medium 100 using the optical modulator 15 when data is recorded. In addition, the control unit 20 is based on the control information recorded in the form of a mark in the data image read by the image sensor 18 at the time of reproduction of the data and the eccentricity / tilt of the recording medium 100 and the reference Not only can the angle of incidence of light be checked, but the timing of the data image can be determined. Here, the control information includes a control mark, a page sync mark, a pixel alignment mark, address information, a gain control mark, and the like. do.

As shown in FIG. 2, the control marks are recorded on both sides of the outside of the user data region (control information region), and indicate whether the data image is deviated from side to side and the degree of deviation. . The controller 20 calculates the sum of the intensities of the light reflected from the control marks, and determines the bias of the data image based on the sum of the intensities of the lights. The page sync mark is recorded on the outer side of the user data area to determine the exact position of the next area when rotating to record / reproduce data in a next book of the recording medium 100. It is also used to determine whether or not the reproduced data image is out of the vertical direction. The page sync mark may be recorded in different sizes or shapes for each book to distinguish the previous area from the next area. The alignment marks are recorded at four outer edges of the user data area, respectively, and are used for optical initial alignment of the light modulator 15 and the image sensor 18. For example, before reproducing the first page data of the predetermined area (book) of the recording medium 100, the control unit 20 on the basis of the alignment mark (align mark) taken by the image sensor 18. It may be determined whether the image sensor 18 is aligned with the data page. The address information is recorded on one side of the lower side outside the user data area and represents an address of each data image. The controller 20 may find a location of desired data by using the address information recorded in the data image and an address stored in the recording / reproducing apparatus when data is recorded. The gain control mark is recorded below the outside of the user data area, and includes a threshold value for discriminating the data recorded in the user data area as "0" and "1". Data recorded in the user data area is recorded at different bit depths, and the gain control mark serves as a reference for determining the level / value of the data according to the bit depth. It is apparent that the positions and number of the marks and address information described above may be modified within a range capable of appropriately performing the function.

The image sensor 18, which is composed of a semiconductor image pickup device such as a charge-coupled device (CCD), receives light that passes through or is reflected from the recording medium 100, and receives the received light. Capture / read the included data image. In other words, the image sensor 18 captures the data image when the light intensity becomes maximum. The image sensor 18 shown in FIG. 1 is arranged to capture a data image passing through the recording medium 100. However, the image sensor 18 may be arranged to receive a phase conjugate signal light (data image) generated in a direction reflected from the recording medium 100 in response to the reference light.

When data is recorded on the recording medium 100, by varying the incident angle of the reference light, the data image of several pages may be recorded so as to overlap one area of the recording medium 100. This is because data included in the signal light is recorded on the recording medium 100 in different interference patterns according to the incident angle of the reference light. In order to reproduce the data recorded by the holographic method, only the reference light should be irradiated to the recording medium 100, and the incident angle of the reference light should exactly match the incident angle at the time of recording.

A data recording method using the data recording / reproducing apparatus of the present invention is as follows. 3 is a flowchart showing a data recording method of the present invention.

When data is recorded on the recording medium 100, the control unit 20 first places the mirror of the reference light control unit 14 to a point where data can be recorded. For example, the mirror of the reference light control unit 14 is moved to a position / angle capable of recording the data image of the first page in the corresponding area of the recording medium 100.

Then, the light output from the light source unit 11 is transmitted to the first light splitter 13, and the light transmitted to the first light splitter 13 is divided into reference light and signal light and then the reference light adjuster ( 14) and the light modulator 15, respectively. At this time, the optical modulator 15 patterns the user data and the control information to be recorded and includes the same in the signal light (S31). In this case, the signal light is modulated so that the user data is recorded in the user data area, and the control information is recorded outside the user data area (control information area).

When the signal light is irradiated to the recording medium 100 through the optical modulator 15 and the reference light is irradiated to the recording medium 100 through the reference light adjusting unit 14 (S32), the signal light And while the reference light interferes with each other, the data included in the signal light is recorded in the hologram form on the recording medium (100) (S33). In this case, the mirror of the reference light control unit 14 continuously changes the incident angle of the reference light from the minimum incident angle to the maximum incident angle according to the command of the controller 20. During scanning from the minimum incident angle to the maximum incident angle, multiple pages of data images may be sequentially recorded on the recording medium 100. Here, the minimum incident angle is the incident angle of the reference light for reading the first page data, and the maximum incident angle is the incident angle of the reference light for reading the last page data.

In addition, while the data image is recorded on the recording medium 100, the controller 20 stores the address of each data image and the incident angle of the reference light incident when the data image is recorded in the memory 17. (S34). The address and the reference light incident angle may also be stored in the control information area of the recording medium 100.

When all data images are recorded in a predetermined area of the recording medium 100, the controller 20 determines whether to further record the data image in the next area (S35), and if necessary, in the next area. The reference light adjusting unit 14 is moved to record data, and then data is recorded according to the above-described method. When recording data in the next area, the page sync mark may be recorded differently from the page sync mark included in the data images of the previous area.

The data reproducing method using the data recording / reproducing apparatus of the present invention is as follows. 4 is a flow chart showing a data reproduction method of the present invention. In this case, the term "replay" refers to an operation of reading stored data, and includes meanings of executing a stored computer program, outputting and copying of stored data, and the like.

In the case of reproducing the data stored in the recording medium 100, the control unit 20 first places the mirror of the reference light control unit 14 as a point capable of reproducing the data. That is, the controller 20 reads the address of the data to be reproduced and the reference light incident angle corresponding thereto from the memory 17 or the recording medium 100 and based on the read address and the reference light incident angle. The mirror is moved to a position where the reference light can be irradiated to the corresponding area of the recording medium 100 (S41). In particular, it is preferable to position the mirror of the reference light control unit 14 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. .

In addition, while the reference light is continuously irradiated to a predetermined region of the recording medium 100 at the minimum incident angle to the maximum incident angle or the maximum incident angle to the minimum incident angle (S42), the controller 20 controls the recording medium 100. In step S43, the control information recorded in the control unit is detected (S43), and the corresponding data image is reproduced based on the detected control information (S44). In particular, the controller 20 determines a photographing time point of each data image based on a control mark, a page sync mark, an align mark, etc. photographed by the image sensor 18. That is, based on the marks, it is determined that the mirror angle (the incident angle of the reference light) of the reference light adjusting unit 14 and the alignment state of the image sensor 18 are the most accurate, and the corresponding data page is determined at that time. Control to shoot. For example, as shown in FIG. 5, the sum of the intensities of the light reflected by the control mark is calculated, and the left and right bias of the data image is determined based on a result of comparing the sum of the intensities with a reference value. If the sum of the light intensities is smaller than the reference value, it is determined that the data image is skewed left and right.

The controller 20 reproduces the first data image based on the control information of the first data image, and reproduces the second data image based on the control information of the second data image. That is, while the incident angle of the reference light is changed, each data image is reproduced according to the corresponding control information.

In addition, if the angle of the reference light control unit 14 and the position of the image sensor 18 is not correct, the control unit 20 may control the angle of the reference light control unit 14 and the image sensor. The position of (18) can be readjusted.

During scanning from the minimum incidence angle to the maximum incidence angle, several pages of data recorded on the recording medium 100 are reproduced in sequence, and then the image sensor 18 records the reference value recorded in the gain control mark. After converting the photographed data image into an electrical signal by using the transfer the electrical signal to a computer or an audio / video device.

When all page data recorded in a certain area of the recording medium 100 is reproduced, the control unit 20 determines whether to further reproduce data recorded in another area (S45), and if necessary, data recorded in another area. The reference light adjusting unit 14 is moved to reproduce the data, and the data is reproduced according to the above-described method. That is, the mirror is moved to a position where the reference light can be irradiated to a next book based on an address stored in the memory 17 or the recording medium 100 and a reference light incident angle, and then the page It is determined whether the position of the next region is correct based on the sync mark, and whether the angle of the reference light adjusting unit 14 and the position of the image sensor 18 are correct using other marks.

According to the present invention, when recording / reproducing data using the multiplexing method, it is possible to accurately determine a photographing time point of a data image based on control information recorded in the data image while the incident angle of the reference light is continuously changed. . In addition, the deviation of the reference light incident angle which may be caused by deformation or tilting of the recording medium may be compensated based on the control information.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

Claims (29)

Irradiating light onto a predetermined area of the recording medium while changing the incident angle; Detecting control information from the light diffracted by the recording medium; And reading the data recorded on the recording medium on the basis of the detected control information. The method of claim 1, Irradiating light to a predetermined area of the recording medium while changing the incident angle, And irradiating the light while changing from a minimum incident angle for reproducing the first data recorded in a predetermined area of the recording medium to a maximum incident angle for reproducing the last data. The method of claim 1, Detecting control information from the light diffracted by the recording medium, Photographing a data image including a user data area and a control information area from the light; Detecting the control information recorded in the control information area. The method of claim 3, wherein And detecting the control information in the control information area located around the user data area. The method of claim 3, wherein The control information, At least one of a mark indicating left and right eccentricity of the data image, a mark indicating up and down eccentricity of the data image, address information of the data image, a mark for distinguishing an area of the recording medium, and a reference value for data determination Data reproduction method comprising a. The method of claim 1, Reading the data recorded on the recording medium on the basis of the detected control information, And determining a reading time point of the data recorded on the recording medium based on the control information. The method of claim 1, Reading the data recorded on the recording medium on the basis of the detected control information, Determining at least one of an eccentricity / tilt of the recording medium and an incident angle of the light based on the control information; And adjusting the direction / incidence angle of the light according to the determination result. A light control unit for irradiating light to a predetermined area of the recording medium while changing the incident angle; And an optical detector for detecting control information from the light diffracted by the recording medium and reading data recorded on the recording medium based on the detected control information. The method of claim 8, The light control unit, And irradiating the light while changing from a minimum incident angle for reproducing the first data recorded in a predetermined area of the recording medium to a maximum incident angle for reproducing the last data. The method of claim 8, The light detector, And a data image including a user data area and a control information area from the light, and detecting the control information recorded in the control information area. The method of claim 10, The light detector, And the control information is detected in the control information area located around the user data area. The method of claim 10, The control information, At least one of a mark indicating left and right eccentricity of the data image, a mark indicating up and down eccentricity of the data image, address information of the data image, a mark for distinguishing an area of the recording medium, and a reference value for data determination Data reproducing apparatus comprising a. The method of claim 8, And a control unit for determining a reading time point of the data recorded on the recording medium on the basis of the control information. The method of claim 13, The control unit, And determining at least one of an eccentricity / tilt of the recording medium and an incident angle of the light based on the control information, and adjusting the direction / incidence angle of the light according to the determination result. Generating a first light comprising user data and control information; Irradiating the first light to a predetermined area of the recording medium and irradiating a second light to the predetermined area of the recording medium while changing the incident angle to record the user data and the control information in the predetermined area of the recording medium. Wow; And storing the address of the recorded user data and the incident angle of the second light. The method of claim 15, Recording the user data and the control information in a predetermined area of the recording medium; And recording the user data and the control information in a predetermined area of the recording medium in the form of a data image including a user data area and a control information area. The method of claim 16, The control information, At least one of a mark indicating left and right eccentricity of the data image, a mark indicating up and down eccentricity of the data image, address information of the data image, a mark for distinguishing an area of the recording medium, and a reference value for data determination Data recording method comprising a. The method of claim 16, The control information, And the control information area located around the user data area. The method of claim 15, In the storing of the address of the recorded user data and the incident angle of the second light, And storing the address of the user data and the incident angle of the second light on the recording medium. The method of claim 15, In the storing of the address of the recorded user data and the incident angle of the second light, And an address of the user data and an incident angle of the second light in a data recording / reproducing apparatus. A first light output unit for irradiating a predetermined area of the recording medium with a first light including user data and control information; A second light output unit for irradiating a second light while varying an angle of incidence in a predetermined region of the recording medium to which the first light is irradiated; And a controller for outputting the address of the user data and the incident angle of the second light. The method of claim 21, The first light output unit, And recording the user data and the control information in a predetermined area of the recording medium in the form of a data image including a user data area and a control information area. The method of claim 22, The control information, At least one of a mark indicating left and right eccentricity of the data image, a mark indicating up and down eccentricity of the data image, address information of the data image, a mark for distinguishing an area of the recording medium, and a reference value for data determination Data recording apparatus comprising a. The method of claim 22, The first light output unit, And record the control information in the control information area located around the user data area. The method of claim 21, The control unit, And an address of the user data and an incident angle of the second light on the recording medium. The method of claim 21, The control unit, And the address of the user data and the incident angle of the second light are stored in a memory of the data recording apparatus. In a recording medium for recording a plurality of data images, A user data area located in a predetermined area of the data image, in which user data is recorded; And a control information area located in another area of the data image except for the user data area, in which control information for controlling reproduction of the data image is recorded. The method of claim 27, The control information, And recording information indicating the point of time when the data image was taken. The method of claim 27, The control information, At least one of a mark indicating left and right eccentricity of the data image, a mark indicating up and down eccentricity of the data image, address information of the data image, a mark for distinguishing an area of the recording medium, and a reference value for data determination Record medium comprising a.

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