JP2004213809A - Method and apparatus for correcting tilt of optical disk - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably perform tilt correction without being affected by a recording state and to avoid an influence of a defect or the like. <P>SOLUTION: Tilt is detected at a plurality of positions where a skew sensor 50 provided in an optical pickup 31 is moved in a fixed interval in the radial direction of an optical disk 2, the above tilt detection result is detected to fall within a certain threshold in a certain range to thereby find a place where there is no change in a recording state of the optical disk 2 and in the place, a microcomputer 39 supplies a skew servo driving signal to a skew motor driver 53 for driving a skew motor 52 to perform tilt correction on the basis of the above tilt detection. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical disk suitable for being applied to a recording device or a reproducing device for a disk (hereinafter, these disks are simply referred to as an optical disk) for optically recording or reproducing, such as an optical disk, a magneto-optical disk, and a phase change disk. The present invention relates to a tilt correction method and a tilt correction device.
[0002]
[Prior art]
An optical disc apparatus that performs recording or reproduction of an optical disc records data on the track while performing tracking servo control to follow a track formed on the disc with a laser beam from an optical pickup, or records data on the track. Processing to reproduce the data.
[0003]
An optical disk such as a compact disk (CD: Compact Disc) has a large storage capacity and allows random access. In addition, since optical reading is non-contact, there is less danger such as head crash and wear and damage due to reading as compared with a contact type recording medium such as a magnetic tape. In addition, the durable disk surface reduces the risk of accidental data loss. An optical disk having many advantages as described above is an excellent recording medium as a memory around a computer and in data production and data storage.
[0004]
In recent years, a recording / reproducing apparatus using a write-once optical disc called a CD-R (Compact Disc-Recordable) has been developed.
[0005]
In such a CD-R, writing corresponding to all standard formats used in compact discs such as CD-ROM, CD-ROM / XA, CD-I, and CD-DA is easily performed. Some can be done. In addition, CD-Rs are being used as recording / reproducing devices for recording and / or reproducing data mounted on electronic devices instead of conventional magnetic tapes, magnetic disks, and the like.
[0006]
In addition, a DVD-R (DVD-Recordable) that can be written only once and a DVD-RW (DVD-RW) that can be written once can be used as an optical disk on which information can be written even on a DVD that is an optical disk that handles a large amount of data such as video data. Rewritable) and DVD-RAM (DVD-Random Access Memory) are provided.
[0007]
It is also known that the adoption of a tracking servo method called a DPP (Differential Push Pull) method makes it possible to favorably follow tracks formed on an optical disk. In order to properly reproduce recorded data on an optical disk with a very high recording density, it is necessary to not only increase the accuracy of the tracking servo control but also to correct the angle between the disk and the optical pickup. It is necessary to perform tilt correction) control. That is, when irradiating a laser beam to a track originally formed on an optical disk, it is necessary to irradiate the laser beam in a state orthogonal to the signal recording surface on which the track is formed. On the other hand, an optical disk formed of a resin material or the like often has warpage in a storage state or the like.In the case of a disk with this warp, when a laser beam scans a warped portion of a track, The state between the laser beam and the signal recording surface does not become orthogonal, and the recorded data cannot be read correctly.
[0008]
For this reason, the distance or inclination between the disk surface (or signal recording surface) and the optical pickup is detected by some kind of sensor, and the inclination of the optical pickup is corrected in accordance with the detected signal, so that the laser beam is always applied to the signal recording surface. Skew servo control is performed so that irradiation is performed in a state perpendicular to the skew servo control.
[0009]
Conventionally, skew detection is performed, for example, as follows.
[0010]
The light emitting diode emits light, and the reflected light from the medium is detected by the two detectors A and B, and the inclination of the medium is detected based on the difference between the light amounts of the detectors A and B.
[0011]
Usually, when the inclination is 0 (the optical axis of the laser emitted from the optical pickup and the medium are perpendicular), A = B is designed.
[0012]
The value of A-B is a value of the inclination. However, since A-B changes depending on the reflectance of the medium and the intensity of the light source, the value is normalized so as not to depend on the above value by dividing by A + B. You.
[0013]
Actually, the outputs of the detectors A and B are input to an AD converter such as a microcomputer via an amplifier. The outputs of the detectors A and B are first input to the AD converter in a state where there is no reflected light and no incident light in order to cancel the influence of the amplifier offset and stray light in order to obtain the intensity of only the reflected light. The reflected light output of the light is obtained by reducing the value at the time of detection.
[0014]
The skew servo control is performed as follows.
[0015]
First, an offset is obtained and stored.
[0016]
Playback is performed by using a reference disc, or recording and playback of media is performed to change the tilt so that jitter and error rate are optimum, thereby obtaining an optimum tilt.
[0017]
In this state, the outputs of the detectors A and B are detected, and the value of (AB) / (A + B) at that time is stored as a reference value. This value is a value specific to the optical pickup.
[0018]
Next, when another medium is loaded, the value of A / B is detected to check whether the value of (AB) / (A + B) is the same as the reference value. Is turned so that the above reference value is obtained.
[0019]
[Problems to be solved by the invention]
By the way, the detected value of A / B in the conventional skew detection as described above is affected by the recording state. For example, a recorded area and an unrecorded area have a difference in reflectance, which causes a bias in the output of the detector A, which exists in a different state in the radial direction.
[0020]
That is, for example, when there is a recording state as shown in FIG. 4, the detection output produces a value that is significantly different from the original inclination at the boundary in accordance with the recording state.
[0021]
If the detected position is a boundary position between a recorded state and an unrecorded state, the influence is so great that the inclination cannot be corrected correctly.
[0022]
Accordingly, an object of the present invention is to provide a tilt correction, that is, a skew servo that can be stably executed without being affected by a recording state, and to avoid the influence of a defect, etc., in view of the conventional problems as described above. It is an object of the present invention to provide an optical disk tilt correction method and a tilt correction device which are capable of performing the above.
[0023]
[Means for Solving the Problems]
The present invention emits light, detects reflected light from an optical disk with a plurality of detectors, performs an operation based on the amount of light, detects the inclination of the optical disk, and adjusts the detected result with the optical disk so that the detected result becomes a constant value. A tilt correction method for correcting a tilt by changing a relative tilt, wherein tilt detection is performed at a plurality of positions moved at regular intervals in the radial direction of the optical disc, and the tilt detection result falls within a certain threshold within a certain range. By detecting that the optical disc is in the optical disc, a location where there is no change in the recording state of the optical disc is obtained, and the inclination is corrected at that location based on the inclination detection.
[0024]
In the tilt correction method for an optical disk according to the present invention, the plurality of positions for performing the tilt detection are at least three.
[0025]
Further, in the optical disk tilt correction method according to the present invention, when the tilt detection result does not fall within a certain threshold, the tilt is moved again by a distance corresponding to the influence range at the boundary of the recording state. Perform detection.
[0026]
The present invention emits light, detects reflected light from an optical disk with a plurality of detectors, performs an operation based on the amount of light, detects the inclination of the optical disk, and adjusts the detected result with the optical disk so that the detected result becomes a constant value. A tilt correction device that corrects tilt by changing the relative tilt, detects tilt at a plurality of positions moved at regular intervals in the radial direction of the optical disc, and within a certain range, the result of the tilt detection is within a threshold. The optical disc drive further comprises a control means for determining a position where the recording state of the optical disc does not change by detecting that the optical disk is in the optical disc, and performing tilt correction based on the tilt detection at the position.
[0027]
In the tilt correcting apparatus for an optical disk according to the present invention, the control means performs the tilt detection at at least three positions.
[0028]
In the tilt correction apparatus for an optical disk according to the present invention, the control means may move the tilt by a distance corresponding to the influence range at the boundary of the recording state when the tilt detection result does not fall within a certain threshold. At the set position, tilt detection is performed again.
[0029]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0030]
The present invention is applied to, for example, a disc camcorder 1 having a configuration as shown in the block diagram of FIG.
[0031]
The disc camcorder 1 records an imaging result on an optical disc 2 of DVD-R (DVD-Recordable) or DVD-RW (DVD-Rewritable). Control unit 11 for generating an operation control signal in response to an operation input by the user, and an HI control unit for executing transmission and reception of various information with other components in accordance with at least the operation control signal output from the front control unit 11 12, a camera unit 13 for capturing an image of an object to generate an image signal, a camera control unit 14 for controlling the camera unit 12, a system controller 15 for controlling each component, a codec process for compressing and expanding image signals Unit 16 and the system controller 15 to communicate information to the user. Comprising an LCD panel 17 for displaying the.
[0032]
The disk drive 3 includes a drive control unit 19, a drive chip set 20 disposed between the system controller 15 and the drive control unit 19, and the like.
[0033]
The front control unit 11 generates an EJECT signal in response to a pressing input of an eject switch provided on the outer surface of the housing of the disc camcorder 1, and transmits the EJECT signal to the HI control unit 12. The front controller 11 generates a PW signal in response to a pressing input of a power switch provided on the outer surface, and transmits the PW signal to the HI controller 12. Further, the front control unit 11 executes clock control in the disc camcorder 1, generates a predetermined operation control signal according to the type of the key pressed and input, and transmits this to the HI control unit 12. Incidentally, the key press input may be replaced by receiving a wireless signal transmitted from a remote controller terminal (not shown).
[0034]
The HI control unit 12 generates an EJ control signal based on the EJECT signal received from the front control unit 11, and transmits the EJ control signal to the drive control unit 19 of the disk drive 3. The HI control unit 12 controls ON / OFF of the power of the disc camcorder 1 based on the PW signal received from the front control unit 11. The HI controller 12 transmits and receives various information to and from the camera controller 14 via, for example, an I / O sync bus, and transmits and receives various information to and from the system controller 15 via the bus. The HI control unit 12 generates a command based on various operation control signals received from the front control unit 11 and transmits the command to each component, or executes a predetermined operation. For example, when the recording mode and the reproduction mode are designated by the user via the front control unit 11, an operation control signal to that effect is transmitted to the HI control unit 12. The HI control unit 12 identifies the details of the specified mode based on the operation control signal, and transmits a predetermined control signal to the drive control unit 19 of the disk drive 3.
[0035]
The HI control unit 12 also controls DVD playback navigation and performs data communication with other electronic devices via a USB (Universal Serial Bus) interface or the like.
[0036]
The camera unit 13 generates an image signal by photoelectric conversion using, for example, a CCD image sensor based on the captured subject. The camera unit 13 removes noise components by performing, for example, correlated double sampling processing on the generated image signal, and performs signal processing such as shading correction, masking correction, knee correction, γ correction, and contour compensation. Is further amplified and supplied to the HI controller 12 via the camera controller 14.
[0037]
The camera control unit 14 performs mechanical shutter control, strobe control, camera shake correction, and the like in addition to control of video signal processing in the camera unit 13, zoom adjustment, pan / tilt adjustment, and focus adjustment.
[0038]
The codec processing unit 16 generates video data by converting an image signal obtained by the camera unit 13 into a digital signal. The codec processing unit 16 performs data compression based on the MPEG (Moving Picture Experts Group) 2 system based on the control of the system controller 15 when the generated video data is a moving image, and when the generated video data is a still image, And data compression based on the JPEG (Joint Photographic Coding Experts Group) method. The compressed video data is transmitted to the drive control unit 19 of the disk drive 3 and further transmitted to another electronic device via a USB cable connected to the HI control unit 12. This allows the disc camcorder 1 to monitor the imaging result and the reproduction result with an external device. Incidentally, the codec processing unit 16 may generate a thumbnail image for the compressed video data.
[0039]
At the time of reproduction, the codec processing unit 16 decompresses video data based on the reproduced RF signal read from the optical disc 2 in accordance with the above-described method.
[0040]
At the time of recording, the system controller 15 time-division multiplexes the video data output from the codec processing unit 16, and adds header information unique to the DVD, header information of the extension file, and the like to this. Further, the system controller 15 generates data such as UDF, VMG, and VTSI, and outputs the data to the drive control unit 19 of the disk drive 3. Further, at the time of recording, the system controller 15 generates an error correction code using a RAM (not shown) and adds the error correction code to the video data. At this time, the system controller 15 may execute processing such as scrambling and 8/15 modulation on the video data.
[0041]
The system controller 15 executes graphic processing on the LCD panel 17 and controls the brightness of a backlight and the like provided on the back of the LCD panel 17.
[0042]
The LCD panel 17 functions as an electronic viewfinder, and includes a large number of liquid crystal display elements and the like, and constitutes a display for displaying information to a user. The LCD panel 17 displays a predetermined message under the control of the system controller 15.
[0043]
The drive control unit 19 of the disk drive 3 controls recording and reading processing of video data to and from the optical disk 2 and also controls spindle drive of the optical disk 2, focus drive, tracking drive, and sled drive of the optical pickup. Further, the drive control unit 19 controls an ejection mechanism for a user to eject the optical disc 2 inserted into the disc drive 3 based on the EJ control signal transmitted from the HI control unit 12.
[0044]
The configuration of the disk drive 3 will be described later in detail.
[0045]
In the disk camcorder 1 having the above-described configuration, video data can be generated by compressing an image signal based on a captured subject by a predetermined method, and can be recorded on the optical disk 2. At the time of reproduction, the video data read from the optical disk 2 can be expanded and displayed on the LCD panel 17 or transmitted to another electronic device for monitoring.
[0046]
Next, the details of the disk drive 3 will be described with reference to the block diagram shown in FIG.
[0047]
As shown in FIG. 2, the drive 3 includes an optical pickup 31 that records video data on the inserted optical disc 2 or detects video data recorded on the optical disc 2, and a spindle motor that rotates the optical disc 2. 32, a thread motor 33 for moving the optical pickup 31 in the radial direction of the optical disk 2, an RF amplifier 34 connected to the optical pickup 31, a signal from the RF amplifier 34 is transmitted to the storage unit 37, and various servo drive signals are transmitted. A digital signal processor (DSP) 35 to be generated, a thread motor 33 and a drive IC 36 for controlling a two-axis coil (not shown) in the optical pickup 31 based on a servo drive signal from the connected DSP 35, A spindle driver 38 for controlling the spindle motor 32 based on the servo drive signal from the DSP 35, a skew sensor 50 for detecting a relative inclination between the optical disk 2 and the optical pickup 31, an amplifier 51 connected to the skew sensor 50, A skew motor 52 for changing the inclination of the optical pickup 31 with respect to the optical disk 2, a skew driver 53 for driving the skew motor 52 based on a skew servo drive signal, and a microcomputer (hereinafter simply referred to as a microcomputer) 39 for controlling these components. , A DSP 35 and a flash memory 40 for storing programs to be executed for the microcomputer 39, a temperature sensor 41 for detecting the temperature in the disk drive 3 and a shock sensor for detecting an impact, etc. 42 and the like.
[0048]
The optical pickup 31 emits a laser beam from a built-in semiconductor laser, and focuses the laser beam on an information recording surface of the optical disc 2 via an objective lens. The return light obtained from the optical disc 2 by the irradiation of the laser beam is guided to a predetermined light receiving element via the objective lens, and the light receiving result of the light receiving element is output to the RF amplifier 34. The optical pickup 31 uses a biaxial coil (not shown) to move the objective lens of the optical pickup 31 in the optical axis direction and at right angles to the optical axis direction based on a focus drive signal and a tracking start signal supplied from the drive IC 36. Move in the direction.
[0049]
A disk table on which the optical disk 2 is mounted is integrally attached to the spindle motor 32. The spindle motor 32 drives the drive shaft at a constant linear velocity (CLV: Constant Linear Velocity) or a constant angular velocity (CAV: Constant Angular Velocity) based on a spindle drive signal supplied from the spindle driver 38, for example. Then, the optical disk 2 mounted on the disk table is rotated.
[0050]
The sled motor 33 moves the optical pickup 31 in the radial direction of the optical disc 2 based on a sled drive signal supplied from the drive IC 36.
[0051]
In the disk drive 3 having such a configuration, the spindle motor 32 and the sled motor 33 adjust the rotation speed of the optical disk 2, the position of the optical pickup 31, etc., while controlling the laser from the optical pickup 31 to the recording surface of the optical disk 2. Irradiate light. Thereby, the recording surface of the optical disk 2 can be locally heated to record desired data.
[0052]
The RF amplifier 34 includes a current-voltage conversion circuit, an amplification circuit, a matrix operation circuit, and the like. From a detection output obtained by a detector of the optical pickup 31, a reproduction RF signal, a tracking error signal (hereinafter, referred to as a TE signal), and a focus. An error signal (hereinafter, referred to as an FE signal) and the like are generated. The RF amplifier 34 outputs management information transmitted from the optical pickup 31 to the DSP 35 in addition to the generated reproduced RF signal, TE signal, and FE signal.
[0053]
Further, the RF amplifier 34 outputs a light amount control signal for controlling the light amount of the laser light emitted from the optical pickup 31 to the optical disc 2. The RF amplifier 34 keeps the light amount of the laser beam irradiated from the optical pickup 31 to the optical disk 2 constant during reproduction, while changing the signal level of this light amount control signal according to the video data from the DSP 35 during recording. Let it.
[0054]
The DSP 35 is equivalent to the drive chip set 20, binarizes the input reproduction RF signal under the control of the microcomputer 39 corresponding to the drive control unit 19, and transmits it to the system controller 15 or the codec processing unit 16. Will be. The DSP 35 transmits the TE signal and the FE signal generated by the RF amplifier 34 to the drive IC 36. In recording, the DSP 35 generates a recording pulse based on the video data transmitted from the codec processing unit 16 and outputs the recording pulse to the optical pickup 31. Further, the DSP 35 temporarily stores management information of data to be recorded on the optical disc 2 in, for example, the flash memory 40. Further, the DSP 35 receives the instruction from the system controller 15 and controls each unit to execute various reproduction methods such as random reproduction and shuffle reproduction while referring to the management information stored in the flash memory 40.
[0055]
The drive IC 36 generates a focus drive signal and a tracking start signal based on the TE signal and the FE signal input from the DSP 35, and supplies them to the optical pickup 31. Further, the drive IC 36 generates a sled drive signal for moving the optical pickup 31 to a target track position under the control of the microcomputer 39, and supplies this to the sled motor 33.
[0056]
The spindle driver 38 generates a spindle drive signal for rotating the spindle motor 32 at a predetermined speed under the control of the microcomputer 39, and supplies this to the spindle motor 32.
[0057]
The storage unit 37 is configured by, for example, a random access memory (RAM) or the like, and temporarily stores a reproduction RF signal transmitted from the DSP 35. The reproduction RF signal stored in the storage unit 37 is read out at a predetermined timing under the control of the microcomputer 39.
[0058]
The microcomputer 39 corresponds to the drive control unit 19, controls the recording and reading processing of video data on the optical disk 2, and drives the spindle of the optical disk 2, the focus drive, the tracking drive, and the thread drive of the optical pickup 31. , Skew drive and the like.
[0059]
As shown in FIG. 3, the skew sensor 50 includes a light-emitting diode 50L that emits detection light for irradiating the optical disc 2, and two-segment photodetectors 50A and 50B that receive detection light reflected by the optical disc 2.
[0060]
The skew sensor 50 detects the relative inclination between the optical disc 2 and the optical pickup 31 based on the difference between the amount of light received by the two-segment photodetectors 50A and 50B that makes the light emitting diode 50L emit light and receives the reflected light from the optical disc 2. , The optical pickup 31.
[0061]
When the optical axis of the laser beam emitted from the optical pickup 31 to the optical disc 2 is perpendicular to the optical disc 2, that is, when the tilt is 0, the skew sensors 50 receive the same amount of light from the two-divided photodetectors 50 </ b> A and 50 </ b> B. , 50B are designed such that A = B.
[0062]
The amplifier 51 to which the detection outputs A and B obtained by the two-divided photodetectors 50A and 50B of the skew sensor 50 are supplied supplies the difference signal (AB) and the sum signal (A + B) to the microcomputer 39.
[0063]
The microcomputer 39 generates the skew servo drive signal based on the difference signal (A−B) supplied from the amplifier 51 based on the sum signal (A + B), and supplies the generated skew servo drive signal to the skew motor driver 53, thereby controlling the skew motor 52. The skew servo control is performed to drive the optical disc 2 and the optical pickup 31 so that the relative inclination between the optical disc 2 and the optical pickup 31 is optimal.
[0064]
Here, the skew servo control by the microcomputer 39 is performed as follows.
[0065]
First, an offset is obtained and stored.
[0066]
Playback is performed with a reference disc, or the optical disc is recorded / reproduced, and the tilt is changed so as to obtain the optimum jitter and error rate.
[0067]
In this state, the skew detection is performed by dividing the difference signal (AB) supplied from the amplifier 51 by the sum signal (A + B) for the detection outputs A and B obtained by the two-divided photodetectors 50A and 50B of the skew sensor 50. The signal is normalized, and the value (Vdes) of (AB) / (A + B) at that time is stored in the flash memory 40 as a reference value. This value Vdes corresponds to the sensor itself or the mounting offset of the sensor, and is a value unique to the optical pickup.
[0068]
The processing up to this point is performed before shipment from the factory.
[0069]
In the disk drive 3 of the disk camcorder 1, before executing the skew servo with the optical disk 2 actually mounted, whether the detection position is appropriate before executing the skew servo, Check if it is not the boundary of the unrecorded part.
[0070]
The microcomputer 39 performs skew detection at three places, and detects that no large change has occurred in the value.
[0071]
That is, as shown in FIG. 4, when the optical pickup 31 is moved across the boundary between the recorded portion RR and the unrecorded portion NR on the optical disk 2, the optical pickup 31 is obtained by the two-part photodetectors 50A and 50B of the skew sensor 50. Skew detection normalized based on the difference signal (AB) and the sum signal (A + B) generated by the amplifier 51 from the detection outputs A and B, and the difference signal (AB) and the sum signal (A + B). The signal (AB) / (A + B) changes abruptly at the boundary between the recorded portion RR and the unrecorded portion NR, but since the amount of change outside the boundary is small, skew detection is performed at three points. By detecting that no significant change has occurred in the value, it is possible to determine an appropriate position for executing the skew servo.
[0072]
Normally, a difference in inclination such as 0.2 degrees can occur in the entire disc, but no difference such as 0.1 degrees can occur in 1 mm intervals. That is, it is a difference in recording state. Therefore, if the value difference is not within a certain threshold, the location is changed.
[0073]
For example, the position is changed in the inner circumferential direction or the outer circumferential direction by 3 mm. This movement amount may be small, but is set to a length affected by the detection output at the boundary of the recording state in order to shorten the detection time.
[0074]
The disk drive 3 of the disk camcorder 1 executes the skew servo at the position determined in this way according to the procedure shown in the flowchart of FIG.
[0075]
That is, the microcomputer 39 of the disk drive 3 normalizes the skew detection signal based on the current detection outputs A and B of the skew sensor 50, and obtains the value Vdet of AB / A + B at that time (step S1).
[0076]
Then, it is determined whether or not the absolute value of the difference between the obtained value Vdet and the reference value Vdes stored in advance in the flash memory 40 is within a predetermined range V0 (step S2).
[0077]
If the determination result in step S2 is NO, that is, if the skew is large, the microcomputer 39 supplies a skew servo drive signal to the skew motor driver 53 to rotate the skew motor 52 in a direction approaching the target state (step S2). S3).
[0078]
Then, the microcomputer 39 normalizes the skew detection signal based on the current detection outputs A and B of the skew sensor 50, and obtains a value Vdet of (AB) / (A + B) at that time (step S4). It is determined whether the value Vdet has changed (step S5).
[0079]
If the result of the determination in step S5 is YES, that is, if the value Vdet of the normalized skew detection signal (AB) / (A + B) has changed, the process returns to step S2, and the difference from the reference value Vdes is calculated. It is determined again whether the absolute value is within the predetermined range V0.
[0080]
By repeating the processing from step S2 to step S5, the absolute value of the difference between the normalized skew detection signal (AB) / (A + B) value Vdet and the reference value Vdes falls within a predetermined range V0. The skew motor 52 is driven to adjust the skew, and the result of the determination in step S5 is YES, that is, the absolute value of the difference between the normalized value of the skew detection signal (AB) / (A + B) Vdet and the reference value Vdes. The skew adjustment ends when the value falls within the predetermined range V0.
[0081]
During the skew adjustment, if the determination result in step S5 is NO, that is, if the normalized value of the skew detection signal (A−B) / (A + B) Vdet does not change, the skew motor 52 is turned off. It is determined that there is an abnormal state in which something has come into contact, a skew adjustment error is displayed, and the process ends.
[0082]
【The invention's effect】
As described above, according to the present invention, tilt detection is performed at a plurality of positions moved at regular intervals in the radial direction of the optical disc, and the result of the tilt detection falls within a certain threshold within a certain range. By detecting, a position where the recording state of the optical disk does not change is determined, and the inclination correction is performed based on the inclination detection at that position, so that the inclination correction can be stably executed without being affected by the recording state. Can be. In addition, the influence of defects can be avoided.
[0083]
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a disc camcorder to which the present invention is applied.
FIG. 2 is a block diagram showing a detailed configuration of a disk drive in the disk camcorder.
FIG. 3 is a diagram showing a principle configuration of a skew sensor provided in an optical pickup of the disk drive.
FIG. 4 is a diagram showing a difference signal (A−A) generated by an amplifier from a detection output obtained by a two-segment photodetector of the skew sensor when an optical pickup is moved across a boundary between a recorded portion and an unrecorded portion on an optical disc. B) and the sum signal (A + B), and the waveforms of the skew detection signal (AB) / (A + B) normalized based on the difference signal (AB) and the sum signal (A + B). FIG. 5 is a flowchart showing a procedure of executing a skew servo in the disk drive.
[Explanation of symbols]
1 disc camcorder, 2 optical discs, 3 disc drives, 11 front control section, 12 HI control section, 13 camera section, 14 camera control section, 15 system controller, 16 codec processing section, 17 LCD panel, 19 drive control section, 20 drive Chip set, 31 optical pickup, 32 spindle motor, 33 thread motor, 34 RF amplifier, 37 storage unit, 35 digital signal processor, 36 drive IC, 38 spindle motor driver, 39 microcomputer, 40 flash memory, 41 temperature sensor, 42 Shock sensor, 50 skew sensor, 50L light emitting diode, 50A, 50B 2-split photo detector, 51 amplifier, 52 skew motor, 53 skew motor driver

Claims (6)

Light is emitted, the reflected light from the optical disk is detected by a plurality of detectors, the light amount is calculated, the inclination of the optical disk is detected, and the relative inclination to the optical disk is changed so that the above detection result becomes a constant value. A tilt correction method for correcting the tilt by
The inclination is detected at a plurality of positions moved at regular intervals in the radial direction of the optical disk, and the recording state of the optical disk changes by detecting that the result of the inclination detection is within a certain threshold within a certain range. Seeking a place without
A tilt correction method for an optical disc, wherein tilt correction is performed at the location based on the tilt detection. 2. The optical disc tilt correction method according to claim 1, wherein a plurality of positions where the tilt detection is performed are at least three. 2. The optical disc tilt according to claim 1, wherein when the tilt detection result does not fall within a certain threshold, the tilt detection is performed again at a position moved by a distance corresponding to the influence range at the boundary of the recording state. Correction method. Light is emitted, the reflected light from the optical disk is detected by a plurality of detectors, the light amount is calculated, the inclination of the optical disk is detected, and the relative inclination to the optical disk is changed so that the above detection result becomes a constant value. A tilt correction device that corrects the tilt by causing
The inclination is detected at a plurality of positions moved at regular intervals in the radial direction of the optical disk, and the recording state of the optical disk changes by detecting that the result of the inclination detection is within a certain threshold within a certain range. An optical disc tilt correction device, comprising: a control unit that determines a location where there is no error and corrects the tilt based on the tilt detection at the location. 5. The tilt correction device for an optical disk according to claim 4, wherein the control means performs the tilt detection at at least three positions. 5. The method according to claim 4, wherein when the result of the tilt detection does not fall within a certain threshold, the control means performs tilt detection again at a position moved by a distance corresponding to an influence range at the boundary of the recording state. An optical disc tilt correction device according to the above.

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