JP2007018609A - Optical recording and reproducing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase recording capacity and to perform recording and reproduction of normal data by compensating warpage even when a hologram recording medium has the warpage. <P>SOLUTION: An outer peripheral part of the hologram recording medium 100 is freely rotatably supported by three rollers 202a, 202b and 202c at three points and when warpage of the hologram recording medium 100 is detected by an optical pickup 301, a position control part 402 controls actuators 401a, 401b and 401c so that the warpage is compensated to transfer the three rollers in a direction vertical to the surface of the hologram recording medium 100. Thereby, recording capacity is increased, warpage of the hologram recording medium 100 is compensated and data can be normally recorded and reproduced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical recording / reproducing apparatus, and more particularly to correcting a warp of a disk-shaped hologram recording medium used in a hologram recording / reproducing apparatus.

  2. Description of the Related Art Conventional optical recording / reproducing apparatuses for recording / reproducing DVDs, BDs, and the like have attempted to improve recording density by shortening the wavelength of light and increasing the NA of lenses. However, when trying to go to a shorter wavelength beyond the visible light range, there are no short wavelength, high power, inexpensive lasers, there are limitations on servo position control, and there are problems with the characteristics of the recording medium. The theoretical limit is being reached in order to shorten the wavelength and increase the NA of the lens as in the prior art.

  Therefore, research and development of hologram recording, near-field recording, selective multilayer recording, two-photon absorption method, and the like have been conducted as methods for further improving the recording density. However, the technology is not yet ready for commercialization.

  On the other hand, the size of a recording medium used for optical recording / reproduction is generally disk-shaped and has a diameter of 12 cm to 13 cm. The recording density has been discussed at this size, and the total amount of recorded information at this size is calculated. Generally referred to as recording density, it is not appropriate to increase the size of the recording medium in order to increase the recording capacity in practice.

  Therefore, there is a known example in which recording on the inner peripheral portion is enabled by applying rotational drive to the disc-shaped recording medium from the outer peripheral portion, which could not be used as a recording place in the conventional optical disc (for example, Patent Document 1). reference). On the other hand, for example, a functional optical recording medium such as a recording medium in which an IC chip is embedded has come out, but the recording density itself is reduced due to the increase in the non-recordable part such as the IC mounting part and the antenna. . In fact, as shown in FIG. 6, the conventional optical disk 150 also has a hole 100a for the spindle motor, a spindle chuck portion 100b, a non-recordable portion 100d, etc. at the center, and only the portion 100c can be substantially recorded. . Therefore, it is possible to increase the recording capacity by taking the portion 100c as large as possible. In any case, it is an urgent issue to increase the recording density with the same size of the optical disk.

By the way, when a warp (tilt) or the like occurs in the optical recording medium as a general problem in the field of optical recording / reproduction, this warp cannot be removed if it is supported at one central point. Currently, the optical pickup is equipped with a servo mechanism that corrects tilt, but considering future increases in density, the allowable range of focus is reduced, but technology development to correct warpage is also necessary. Yes, but very little has actually been undertaken. According to the method of supporting the optical disk from the outer periphery, the surface blur can be corrected to some extent (for example, see Patent Document 2). However, with the recent increase in density, the recording system in the current examination stage is not at a level where the servo mechanism for tilting can be removed.
JP 62-84945 A (Pages 306-307, Fig. 1) JP 2001-84672 A (Page 3, FIG. 1)

  Here, in the case of specializing in hologram recording / reproduction capable of higher density recording, disk-shaped holograms have been published, although many techniques for position correction in the focus direction and tracking direction with respect to the hologram recording medium have been published. There is no correction technology for warping of the recording medium. It has the peculiarity that hologram recording records wavefront information. When correction is performed by tilting the objective lens in the same way as correction for warping of a conventional optical disc, the shape of interference fringes generated from the reference light and signal light is reduced. This is because there is a possibility that recording or reproduction cannot be performed.

  The present invention has been devised in view of the above circumstances, and an object of the present invention is to increase the recording capacity and correct the warp even when the recording medium is warped, thereby recording and reproducing normal data. It is an object of the present invention to provide an optical recording / reproducing apparatus capable of performing the above.

  In order to achieve the above object, the present invention is an optical recording apparatus for recording data by irradiating a rotating disk-shaped recording medium with light, and includes at least three outer peripheral portions of the disk-shaped recording medium. A rotating body that is rotatably supported by the disk, a warp detecting means that detects a warp of the disk-shaped recording medium, and the recording medium support position of each rotating body independently in a direction perpendicular to the recording medium surface. It is characterized by comprising moving means for moving and position control means for controlling the moving means in accordance with the detected warp to adjust the recording medium support position of each rotating body.

  The present invention is also an optical recording apparatus for recording data by irradiating light to a rotating disk-shaped recording medium, wherein the outer periphery of the disk-shaped recording medium is rotatable at least at three points. A rotating body to be supported; focus detection means for detecting focus information when irradiating the disc-shaped recording medium with the light; and a recording medium support position of each rotating body perpendicular to the recording medium surface. A moving unit that moves the recording medium in a direction; and a position control unit that controls the moving unit according to the detected focus information and simultaneously adjusts the recording medium support position of each rotating body.

  The present invention also relates to an optical reproducing apparatus for reproducing data by irradiating light to a rotating disk-shaped recording medium, wherein the outer periphery of the disk-shaped recording medium is rotatable at least at three points. A rotating body to be supported; a warp detecting means for detecting a warp of the disk-shaped recording medium; and a moving means for independently moving the recording medium support position of each rotating body in a direction perpendicular to the recording medium surface. And a position control means for adjusting the recording medium support position of each rotating body by controlling the moving means in accordance with the detected warpage.

  The present invention also relates to an optical reproducing apparatus for reproducing data by irradiating light to a rotating disk-shaped recording medium, wherein the outer periphery of the disk-shaped recording medium is rotatable at least at three points. A rotating body to be supported; focus detection means for detecting focus information when irradiating the disc-shaped recording medium with the light; and a recording medium support position of each rotating body perpendicular to the recording medium surface. A moving unit that moves the recording medium in a direction; and a position control unit that controls the moving unit according to the detected focus information and simultaneously adjusts the recording medium support position of each rotating body.

  As described above, according to the present invention, the outer periphery of the recording medium is rotatably supported by, for example, three rollers at three points, and when warping of the disk-shaped recording medium is detected, the warping is corrected. By moving the individual rollers in a direction perpendicular to the surface of the recording medium, the warp of the recording medium can be corrected and data can be normally recorded and reproduced. Further, by detecting the focus information of the signal light and the reference light irradiated on the recording medium during the recording / reproducing, and moving the three rollers in a direction perpendicular to the surface of the recording medium so that the light is in focus In addition, it is possible to simplify the optical system by eliminating the need to separately provide a focus actuator. Furthermore, since the central portion of the recording medium can also be used for recording and reproduction, the recording capacity can be increased.

According to the present invention, the outer periphery of the recording medium is rotatably supported by, for example, three rollers at three points, and when the warpage of the disk-shaped recording medium is detected, the three rollers are corrected so as to correct the warpage. By moving the recording medium in the direction perpendicular to the surface of the recording medium, the recording capacity can be increased, and the recording medium can be corrected for warping and data can be normally recorded and reproduced.
In addition, since the outer periphery of the disk-shaped recording medium is supported by a roller and rotated, data can be recorded / reproduced even at the center of the recording medium, and the size of the hologram recording medium can be changed. Therefore, the capacity can be easily increased.
Furthermore, since it is possible to correct the warp of the recording medium without moving the objective lens as in the prior art, the shape of the interference fringes generated from the signal light and the reference light at the time of hologram recording does not change, It is possible to provide a recording medium warpage correction method that is extremely effective for hologram recording.
Further, the outer periphery of the recording medium is rotatably supported by, for example, three rollers at three points, and the focus information of the light applied to the recording medium at the time of recording / reproduction is detected, and the three pieces of light are in focus. By moving the roller in the direction perpendicular to the surface of the recording medium, it is not necessary to separately provide a focus servo mechanism such as means for moving the objective lens, and the optical system can be simplified.

  For the purpose of increasing the recording capacity and correcting the warp even when the recording medium is warped to perform normal data recording / reproduction, the outer periphery of the recording medium can be freely rotated by, for example, three rollers. When the warp of the disk-shaped recording medium is detected, the three rollers are easily realized by moving the three rollers in a direction perpendicular to the surface of the recording medium so as to correct the warp.

  FIG. 1 is a plan view showing a configuration of a disk rotation mechanism of a recording medium of an optical recording / reproducing apparatus according to the first embodiment of the present invention. In particular, a hologram recording / reproducing apparatus will be described as an example. The disc rotation mechanism of the hologram recording / reproducing apparatus supports the disc-shaped hologram recording medium 100 at three points by rollers 201, 202a, 202b arranged at equal intervals on the outer periphery thereof.

  FIG. 2 is a side view of FIG. 1, and rollers 201, 202b, (202a) having V-shaped grooves on the outer periphery support the outer periphery of the hologram recording medium 100 so as to fit into the V-shaped grooves of the respective rollers. The roller 201 is a drive roller driven by a motor 203. However, 202a is not shown and has the same shape as the roller 202b. Reference numeral 301 denotes an optical pickup that records and reproduces data on the hologram recording medium 100.

  Next, the operation of this embodiment will be described. The outer periphery of the hologram recording medium 100 is supported at three points by fitting into the V-shaped grooves of the rollers 201, 202a and 202b. The roller 201 is rotated by the motor 203 at the driving unit to rotate the hologram recording medium 100. At this time, the V-shaped grooves of the rollers 202a and 202b act as a guide and cause a rotational motion by the propagation of motion from the hologram recording medium 100, but do not actually rotate. The optical pickup 301 accesses the rotating hologram recording medium 100 to perform data recording / reproduction. The V-shaped grooves of the rollers 201, 202a, 202b are fitted to the outer peripheral end of the hologram recording medium 100 to position the hologram recording medium 100, and the rollers 201, 202a, 202b function as positioning guides. .

  According to the present embodiment, the outer peripheral end of the hologram recording medium 100 is positioned and supported by the three rollers 201, 202a, and 202b and rotates, so that a recording layer is disposed at the center of the recording surface of the hologram recording medium 100. For example, data can be recorded / reproduced in the central portion, and the recording capacity per recording medium can be increased. Further, as shown in FIG. 3, an IC chip 501, an antenna 502, and the like can be disposed at the center of the hologram recording medium 100, so that the hologram recording medium 100 can be newly added without impairing the recording density of the hologram recording medium 100. It is also possible to add various functions.

  FIG. 4 is a side view showing the configuration of the disk rotation mechanism of the optical recording / reproducing apparatus according to the second embodiment of the present invention. In particular, the hologram recording / reproducing apparatus will be described as an example. As in the first embodiment, the disk rotation mechanism of the hologram recording / reproducing apparatus has three rollers 202a, 202b, 202c arranged at equal intervals on the circumference, and these rollers 202a, 202b, 202c A V-shaped groove on the outer periphery fits the outer peripheral end of the hologram recording medium 100 to support the hologram recording medium 100. The rotation shafts of the rollers 202a, 202b, and 202c are rotatably connected to the actuators 401a, 401b, and 401c, and the rollers 202a, 202b, and 202c move up and down in the rotation axis direction (arrow direction) by the actuators 401a, 401b, and 401c. . The operations of the actuators 401 a, 401 b, and 401 c are controlled by the position control unit 402, and the position control unit 402 inputs tilt information and focus information of the hologram recording medium 100 from the optical pickup 301.

  Next, the operation of this embodiment will be described. In this example, the actuator 401a also serves as a motor, and the rotation axis of the roller 202a is rotated by the actuator 401a to rotate the hologram recording medium 100. At this time, the V-shaped grooves of the rollers 202b and 202c function as a guide and rotate with the rotation of the hologram recording medium 100. Further, the V-shaped grooves of these rollers 202 a, 202 b and 202 c are fitted to the outer peripheral end of the hologram recording medium 100 to position the hologram recording medium 100.

  The optical pickup 301 performs data recording / reproduction with respect to the rotating hologram recording medium 100. At this time, the optical pickup 301 detects tilt information and focus information of the hologram recording medium 100 and inputs them to the position control unit 402. Thereby, the position control unit 402 performs control to correct the tilt of the hologram recording medium 100 based on the tilt information. That is, the position control unit 402 calculates an appropriate amount of movement of each actuator 401a, 401b, 401c based on the tilt information, and rotates each of the rollers 202a, 202b, 202c connected to the actuator 401a, 401b, 401c. The tilt of the hologram recording medium 100 is always corrected by moving the axis up and down. For example, the actuators 401 a, 401 b, and 401 c use piezo elements or the like, and independently move the rollers 202 a, 202 b, and 202 c slightly in the direction perpendicular to the surface of the hologram recording medium 100. When the position control unit 402 detects a deviation in the tilt direction, the position control unit 402 gives different movement amounts to the actuators 401 a, 401 b, and 401 c to control the correction of the warp of the hologram recording medium 100.

  At the same time, the position control unit 402 moves the actuators 401a, 401b, and 401c based on the input focus information so that the focus of the recording / reproducing area of the hologram recording medium 100 accessed by the optical pickup 301 is not shifted. And the rotation axes of the rollers 202a, 202b, 202c are simultaneously moved by the same amount so that the recording / reproducing area of the hologram recording medium 100 is in focus.

  According to the present embodiment, when the hologram recording medium 100 is warped (tilted), the tilt information is detected, and based on the detected tilt information, the respective rotary shafts of the three-point support rollers 202a, 202b, 202c are moved up and down. Accordingly, since the warpage of the hologram recording medium 100 is corrected, normal recording / reproduction can be performed even if the hologram recording medium 100 is warped. At this time, unlike the conventional method of correcting the position by tilting the objective lens, the optical path of the signal light and the reference light does not change and the shape of the interference fringes does not change, so by correcting the warp of the hologram recording medium 100, It is possible to eliminate the problem that data cannot be recorded / reproduced.

  In particular, if the hologram reproducing apparatus includes the rotation mechanism of the present embodiment, even if the hologram recording medium 100 is warped after data recording on the hologram recording medium 100, the warp can be corrected and data can be reproduced.

  In addition, since the focus direction of the hologram recording medium 100 can be corrected by moving the rotation axes of the three-point supported rollers 202a, 202b, and 202c up and down by the same amount, the objective lens is moved for focus servo. The mechanism to be removed can be eliminated, and the configuration of the optical system can be simplified accordingly.

  In this embodiment, the actuator 401a also serves as a motor and supplies power to the roller 202a. However, any actuator may serve as a motor, and any one of the actuators 401a, 401b, and 401c. Two or more may double as a motor. Further, a motor may be prepared separately from the actuator, and this power may be transmitted to the rotating shaft of a roller connected to the actuator.

  In addition, the present invention is not limited to the above-described embodiment, and can be implemented in various other forms in specific configurations, functions, operations, and effects without departing from the gist thereof. For example, in the above-described embodiment, the hologram recording medium 100 is supported at three points. However, the present invention is not limited to this, and the hologram recording medium 100 can be supported at four or more points, and the same mechanism can be applied to obtain the same effect.

  In the above embodiment, the V-shaped groove is provided on the outer peripheral portion of the roller. However, as shown in FIG. 5, a concave groove 200 is provided on the outer peripheral portion of the hologram recording medium 100, and the outer peripheral end of the roller 202 is provided on this. The same effect can be obtained as a configuration in which the portions are fitted. That is, it is only necessary that the hologram recording medium can be supported and positioned by the roller, and the outer peripheral shapes of the roller and the hologram recording medium are not limited to the above.

  In the above-described embodiment, the present invention is applied to the hologram recording / reproducing apparatus. However, the same effect can be obtained even if the present invention is similarly applied to various optical recording / reproducing apparatuses regardless of recording methods such as CD, DVD, MD. Can be obtained.

1 is a plan view showing a configuration of a disk rotation mechanism of a recording medium of an optical recording / reproducing apparatus according to a first embodiment of the present invention. It is a side view of the optical recording / reproducing apparatus shown in FIG. It is the top view which showed the Example of the hologram recording medium. It is the top view which showed the structure of the disc rotation mechanism of the recording medium of the optical recording / reproducing apparatus concerning the 2nd Embodiment of this invention. It is the side view which showed the other fitting shape of the hologram recording medium and the roller. It is the top view which showed the structural example of the conventional disc rotation mechanism.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Hologram recording medium, 200 ... Groove, 201, 202, 202a, 202b, 202c ... Roller, 203 ... Motor, 301 ... Optical pick-up, 401a, 401b, 401c ... Actuator, 402 ... Position control 501 ... IC chip, 502 ... antenna.

Claims (16)

An optical recording apparatus for recording data by irradiating light to a rotating disk-shaped recording medium,
A rotating body that rotatably supports the outer periphery of the disk-shaped recording medium at at least three points;
Warpage detection means for detecting warpage of the disc-shaped recording medium;
Moving means for independently moving the recording medium support position of each rotating body in a direction perpendicular to the surface of the recording medium;
Position control means for adjusting the recording medium support position of each rotating body by controlling the moving means in accordance with the detected warpage;
An optical recording apparatus comprising: An optical recording apparatus for recording data by irradiating light to a rotating disk-shaped recording medium,
A rotating body that rotatably supports the outer periphery of the disk-shaped recording medium at at least three points;
Focus detection means for detecting focus information when irradiating the disc-shaped recording medium with the light;
Moving means for moving the recording medium support position of each rotating body in a direction perpendicular to the surface of the recording medium;
Position control means for controlling the moving means according to the detected focus information and simultaneously adjusting the recording medium support position of each rotating body;
An optical recording apparatus comprising:   The optical recording apparatus according to claim 1, wherein the moving unit is an actuator connected to each of the rotating bodies.   4. The optical recording apparatus according to claim 3, wherein the actuator is coupled to a rotating shaft of the rotating body and also serves as a motor to rotate the rotating body by rotating the rotating shaft.   5. The optical recording apparatus according to claim 1, wherein the recording area of the disk-shaped recording medium also includes a central portion.   6. The optical recording apparatus according to claim 1, wherein a concave groove for fitting an outer peripheral end portion of the rotating body is provided on an outer peripheral surface of the disc-shaped recording medium.   The optical recording apparatus according to any one of claims 1 to 6, wherein the optical recording apparatus is a hologram recording apparatus that records interference fringes of two light beams on a disc-shaped hologram recording medium.   8. The optical recording apparatus according to claim 7, wherein an antenna and an IC chip are arranged in a part of the disc-shaped hologram recording medium. An optical reproducing apparatus for reproducing data by irradiating light onto a rotating disk-shaped recording medium,
A rotating body that rotatably supports the outer periphery of the disk-shaped recording medium at at least three points;
Warpage detection means for detecting warpage of the disc-shaped recording medium;
Moving means for independently moving the recording medium support position of each rotating body in a direction perpendicular to the surface of the recording medium;
Position control means for adjusting the recording medium support position of each rotating body by controlling the moving means in accordance with the detected warpage;
An optical reproducing apparatus comprising: An optical reproducing apparatus for reproducing data by irradiating light onto a rotating disk-shaped recording medium,
A rotating body that rotatably supports the outer periphery of the disk-shaped recording medium at at least three points;
Focus detection means for detecting focus information when irradiating the disc-shaped recording medium with the light;
Moving means for moving the recording medium support position of each rotating body in a direction perpendicular to the surface of the recording medium;
Position control means for controlling the moving means according to the detected focus information and simultaneously adjusting the recording medium support position of each rotating body;
An optical reproducing apparatus comprising:   11. The optical reproducing apparatus according to claim 9, wherein the moving means is an actuator connected to each of the rotating bodies.   12. The optical reproducing apparatus according to claim 11, wherein the actuator is coupled to a rotating shaft of the rotating body and also serves as a motor to rotate the rotating body by rotating the rotating shaft.   13. The optical reproducing apparatus according to claim 9, wherein the reproducing area of the disc-shaped recording medium also includes a central portion.   14. The optical reproducing apparatus according to claim 9, further comprising a concave groove on the outer peripheral surface of the disc-shaped recording medium for fitting the outer peripheral end of the rotating body.   15. The optical reproducing apparatus according to claim 9, wherein the optical reproducing apparatus is a hologram reproducing apparatus that reproduces data by irradiating a disk-shaped hologram recording medium with one light beam.   16. The optical reproducing apparatus according to claim 15, wherein an antenna and an IC chip are arranged on a part of the disc-shaped hologram recording medium.

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