JPH11316956A - Optical recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-reliability optical recording and reproducing device which enables stable track acquisition even in the presence of vibration by detecting the moving speed of an optical head at the end of retrieval and forcibly driving a tracking actuator in the speed reducing, direction when the moving speed is fast. SOLUTION: A moving speed detection part 141 in a DSP(digital signal processor) 125 detects the moving speed of the optical head at the end of retrieval and when the moving speed is fast, a speed reduction drive signal generation part 144 forcibly drives the tracking actuator 132 in the speed reduction direction. After the speed is sufficiently reduced, tracking control is performed to enable stable retrieval wherein high tracking acquisition performance is secured even in the presence of vibration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording / reproducing apparatus for optically recording information on a recording medium or reproducing the recorded information using a light beam from a light source such as a laser. It is about.

[0002]

2. Description of the Related Art In a conventional optical recording / reproducing apparatus, tracking control is performed by moving a converging lens in a radial direction of a record carrier by a tracking actuator. A typical example of this tracking actuator is a four-wire system. The four-wire actuator includes a movable part to which a converging lens is attached and a fixed part. The movable part and the fixed part are connected by four wires (wires) or an elastic body such as rubber. When an electric current is applied to the coil provided in the movable portion, an electromagnetic force is generated between the coil and the permanent magnet provided in the fixed portion, and the electromagnetic force causes the converging lens to move in the radial direction of the record carrier, that is, perpendicular to the track. Can be moved in any direction.

As a search method for a desired information track in such a conventional apparatus, there is a track count method. In this method, the tracking control is temporarily disabled, and the entire optical head including the tracking actuator is moved across the information track on the disk in the radial direction of the record carrier by applying a predetermined voltage to a traverse motor or the like. The tracking error signal output every time the light beam traverses the track is binarized, and by counting the binarized signal, the moving distance can be calculated to detect the distance to the desired track.
When it is detected that a desired track has been reached by counting, tracking control is generally operated.

Further, in a search for an individual information area in a record carrier having an individual information area on the innermost circumference, a mechanical switch is mounted on the innermost circumference because the address cannot be read in this area, and the switch is turned on. Thus, the position of the individual information area was detected.

[0005]

In the above-mentioned conventional optical recording / reproducing apparatus, the tracking control is turned on immediately after counting the number of movements at the time of retrieval. If the moving speed of the optical head is not sufficiently reduced due to the vibration applied to the optical head, the tracking pull-in fails, and the tracking cannot be pulled into the target track.

The present invention has been made in view of the above-mentioned conventional problems, and detects a moving speed of an optical head at the end of movement, and forcibly drives a tracking actuator in a deceleration direction, thereby achieving a stable operation. It is an object of the present invention to provide an optical recording / reproducing device having high tracking pull-in performance.

In the above-mentioned conventional optical recording / reproducing apparatus,
A mechanical switch or sensor, etc. is mounted on the innermost circumference and the position of the individual information area is detected when the switch is turned on. Could not be detected. When the individual information area cannot be reached, the lens is driven in the tracking direction in the positive and negative directions to search the individual information area, so that it takes a very long time to read the individual information area.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has been made in consideration of an optical system for detecting that a light beam has moved to an individual information area with high accuracy and without using a switch or a sensor. It is an object of the present invention to provide a recording and reproducing device.

Further, in the above-mentioned conventional optical recording / reproducing apparatus, reproduction is performed with a constant characteristic without changing the characteristics of an equalizer circuit and a PLL circuit, which are signal reproducing circuits, in accordance with the rotational speed and the linear velocity. For example, CA
A sufficient margin could not be secured for a change in the signal band due to a change in the linear velocity on the inner and outer circumferences of the disk due to V reproduction or the like. Therefore, for example, when the gain crossing point of the PLL is optimally adjusted at the middle circumference, the signal frequency becomes lower at the inner circumference in CAV reproduction, so that the transient response of the PLL control becomes larger, the lock is easily released due to disturbance, and the signal frequency becomes higher at the outer circumference. Therefore, there is a problem that the gain is insufficient and the pull-in becomes poor. In the case of a CD, the cutoff frequency of the equalizer and the boost amount are also about twice the signal frequency difference between the inner circumference and the outer circumference in the case of CD.
It was impossible to provide sufficient frequency characteristics in all bands, and it was difficult to ensure both frequency characteristics and noise reduction, and to ensure signal quality.

[0010]

SUMMARY OF THE INVENTION The present invention relates to an apparatus for recording information on a record carrier or reproducing the recorded information, comprising a light beam converging means for converging and irradiating a light beam onto the record carrier. First moving means for moving the light beam converging means in a direction transverse to the track on the record carrier, track deviation detecting means for generating a signal corresponding to the positional relationship between the light beam and the track, and track deviation detecting means. Tracking control means for driving the first moving means in response to the signal and controlling the light beam to scan on the track;
By moving the light beam converging means, the second moving means for moving the light beam in a direction crossing the track on the record carrier, and the first or second moving means are driven to move the light beam to a desired track. Search control means to be moved;
Moving speed detecting means for detecting the speed of the moving light beam by the search controlling means; and first moving means until the moving speed of the light beam at the end of the movement detected by the moving speed detecting means becomes a predetermined value or less. It is configured to add a deceleration signal synchronized with the speed detection cycle of the moving speed detection means.

The present invention also provides search control means for moving a light beam to a desired track across a track on a rotating record carrier, and obtaining position information on a current track to reach the desired track. Moving number calculating means for calculating the number of moving lines, command means for commanding the moving number calculated by the moving number calculating means to the search control means, and estimation for estimating a time required for a process of acquiring position information on a desired track. Means for correcting the command value of the command means based on the processing time estimated by the estimating means to operate the search control means.

Further, the present invention provides a recording medium having an individual information recording area in which information such as identification information and an encryption key, which is different for each sheet, is arranged and recorded along a part of the circumference of the recording medium. A light beam converging means for converging and irradiating the light beam, a first moving means for moving the light beam converging means in a direction crossing the track on the record carrier, and generating a signal corresponding to a positional relationship between the light beam and the track. By moving the track shift detecting means, the first moving means in accordance with the signal of the track shift detecting means, and controlling the light beam to scan on the track, and moving the light beam converging means. A second moving means for moving the light beam in a direction crossing the track on the record carrier, and driving the first or second moving means so that the light beam is moved across a plurality of tracks. Search control means for moving to a track, dropout detection means for detecting a lack of a reproduced signal due to a flaw, etc., and individual information recording for judging that the light beam has moved to the individual information recording area based on a signal from the dropout detection means. It is provided with an area determining means.

Further, the present invention provides a retrieval control means for moving a light beam to a desired track across a plurality of tracks, and a reproduction signal detection means for generating a reproduction signal by reflected light or transmitted light from a record carrier. Boost switching means for changing the amount of amplification of a high-frequency component in a signal band with respect to a signal from a reproduction signal detecting means, and cut-off switching means for switching a cut-off frequency of a filter for removing high-frequency noise outside the signal band Waveform equivalent means comprising:
The search control means sets the boost switching means and the cutoff switching means in accordance with the track position where the light beam moves.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(First Embodiment) FIG. 1 is a block diagram showing the configuration of an optical recording / reproducing apparatus according to a first embodiment of the present invention.

An optical recording / reproducing apparatus according to the present invention comprises a disk motor 102 for rotating the optical disk 101 at a predetermined number of rotations, and an optical head (a light source 103 such as a semiconductor laser, a coupling, for reproducing information from the optical disk 101). Lens 104, polarizing beam splitter 105, polarizing plate 106, converging lens 107, condenser lens 108, and four-segment photodetector 109) and the entire optical head in a direction perpendicular to the track direction of optical disc 101. Traverse motor 13 for moving
9 is provided.

The light beam generated by the light source 103 is converted into parallel light by a coupling lens 104 and then reflected by a polarizing beam splitter 105 to form a polarizing plate 1.
06, is converged by the converging lens 107, and a light beam spot is formed so as to have a focus point in the thickness direction of the optical disc 101. The light beam spot is applied to the rotating optical disk 101 by a disk motor 102.

The reflected light from the optical disk 101 is transmitted to a converging lens 107, a polarizing plate 106, a polarizing beam splitter 10
5, and is input via a condenser lens 108 to a quadrant photodetector 109, which is a photodetector having a quadrant structure. The outputs of the four-segment photodetector 109 are amplified by preamplifiers 110, 111, 112, and 113, respectively, and signals at diagonal positions of the four-segment photodetector 109 are added by summing amplifiers 114 and 115, respectively. The outputs of the adder amplifiers 114 and 115 are input to a focus control device (not shown), and the position shift signal between the optical beam 101 and the convergence point of the light beam is detected from the difference between the adder amplifiers 114 and 115. , Focus control is performed so that the convergence point is located on the optical disc 101. The detection of the focus position shift signal is called an "astigma method" (for example, Japanese Patent Laid-Open No.
No. 99561). Since the configuration and operation of the focus control device are not directly related to the present invention, the description is omitted.

The tracking control device includes a comparator 1
16, 117, a phase comparator 118, a differential amplifier 119,
It comprises a gain switching circuit 120, a digital signal processor (DSP) 125, a tracking drive circuit 131, and a tracking actuator 132. The outputs of the summing amplifiers 114 and 115 are respectively
The signals are binarized in steps 6 and 117 and input to the phase comparator 118. The phase comparator 118 compares the phase of the binarized signal, and a signal corresponding to the phase advance and the phase delay is input to the differential amplifier 119. The output signal of the differential amplifier 119 is a signal indicating the deviation between the convergence point of the light beam on the optical disk 101 and the track, that is, the optical disk 101
The convergence point of the upper light beam becomes a track shift signal (TE signal) for controlling the scanning on the track. This detection of the TE signal is called a “phase difference method” (for example, Japanese Patent Application Laid-Open No. Sho 62-165737). The TE signal is supplied to the optical disc 101 by the gain switching circuit 120.
The amplitude is changed according to the light amount of the light beam corresponding to the reflectance or the like, and is adjusted to a predetermined amplitude (gain).
25. Further, the TE signal is supplied to the binarization circuit 1
For example, if the TE signal has a positive value, a binary signal is set to a high level if the TE signal has a negative value, and a binary signal is set to a low level if the TE signal has a negative value. You.

The DSP 125 has switches 129 and 13
6 are provided. Each of the switches 129 and 136 is set to the position shown by a solid line when tracking control needs to be performed, that is, when the optical recording / reproducing apparatus is in the recording or reproducing mode, and the optical head moves across the track. When you need to move to another truck,
That is, when in the search mode, it is set at the position indicated by the dotted line. Therefore, the switches 129 and 136 are used to open and close the loop of the tracking control system, during the tracking control (in the recording / reproducing mode) and during the search (in the search mode).
Thus, an operation of switching the drive signals applied to the tracking actuator 132 and the traverse motor 139 is performed.

The DSP 125 has a switch 145.
However, the output signal of the switch 129 is normally set to a position where the output signal is input to the DA converter 130 during tracking control and search. The operation of the switch 145 will be described later in detail.

In the recording / reproduction mode, tracking control is performed. At that time, the TE signal is supplied to the blocks 126, 1
27, 128, 129, 145, 130 are added to the block 131. Also, the signal from the block 128 is divided into blocks 133, 134, 135, 136, 13
The control is added to the block 138 via 7 and the transfer control is also performed. Also, in the search mode, search control is performed, and the binary signal at that time is, in the embodiment shown in FIG. 1, blocks 140, 141, 142, 12
9, 145, 130, and is added to block 131, and blocks 140, 141, 143, 136,
It is also added to block 138 via 137.

First, the recording / reproducing mode will be described. In this case, as described above, the switches 129, 1
36 are set at the positions indicated by the solid lines.

The TE signal adjusted to a predetermined gain is A
An analog signal is converted into a digital signal by the D converter 126, and a phase compensation filter 127 which is a digital filter constituted by an adder, a multiplier and a delay unit
Is input to The phase compensation filter 127 compensates for the phase of the tracking control system. The TE signal whose phase has been compensated by the phase compensation filter 127 is input to the switch 129 via the gain switching circuit 128 for switching the loop gain of the tracking control system. The switch 129 is set at the position indicated by the solid line in the recording / reproducing mode, so that the TE signal passing through the switch 129 is transmitted through the switch 145 to the DA converter 1.
The signal is converted from a digital signal to an analog signal by 30 and input to the tracking drive circuit 131. The tracking drive circuit 131 drives the tracking actuator 132 by appropriately amplifying the current of the tracking control signal and converting the level thereof. In this manner, the tracking actuator 132 is driven such that the convergence point of the light beam on the optical disc 101 scans on a predetermined track,
Tracking control is realized.

The TE signal that has passed through the gain switching circuit 128 is also input to a low-pass filter 133 for limiting the frequency band and removing noise, and after passing through the low-pass filter 133, compensates for the phase of the transfer control system. Is input to the phase compensation filter 134. The low-pass filter 133 and the phase compensation filter 134 are digital filters each including an adder, a multiplier, and a delay unit, like the phase compensation filter 127. The output of the phase compensation filter 134 is
Gain switching circuit 135 for switching the gain of the transfer control system
, The switch 13 in the state shown by the solid line
6 to the DA converter 137. The digital signal is converted into an analog signal by the DA converter 137, input to the traverse motor drive circuit 138, and appropriately subjected to current amplification and level conversion. The traverse motor 139 is driven by the output of the traverse motor drive circuit 138, and the traverse motor 139
When the convergence point of the upper light beam scans on the track, the convergence point of the light beam coincides with the center of the converging lens 107, that is, the optical axis of the light beam converged and irradiated on the optical disc 101 and the converging lens 107 Driving is performed so that the optical axes coincide, and transfer control is realized.

Next, the search mode will be described. In this case, as described above, the switches 129 and 136
Each is set at the position shown by the dotted line.

The outputs of the summing amplifiers 114 and 115 are also input to the summing amplifier 122. Since the output signal RF of the addition amplifier 122 is a signal corresponding to the total amount of reflected light from the optical disc 101, this signal is
To read the track address on the optical disk 101. The address read by the address reading circuit 123 is stored in a microprocessor (CP
U) 124 to recognize the track address where the light beam is located.

When a desired track address is input to the CPU 124, the CPU 124 reads the track address where the current light beam is located, and the moving number calculation unit 146 in the inside reads the desired track address and the current track address. The movement number is calculated from the difference, and DSP1
Send to 25. The target speed generator 140 generates an initial target speed signal based on the track pitch of the optical disc 101 as a record carrier and the number of movements received from the CPU 124. This initial target speed signal is input to the traverse motor 139 via the differential amplifier 143, the switch 136, the DA converter 137, and the traverse motor drive circuit 138, and at the same time, the differential amplifier 142, the switches 129, and
5, input to the tracking actuator 132 via the DA converter 130 and the tracking drive circuit 131,
The light beam moves toward the target track.

When the light beam traverses the track, a sinusoidal TE signal appears at the output of the differential amplifier 119, and this T signal
The E signal is converted into a binarized signal by the binarizing circuit 121 and input to the target speed generating unit 140 and the moving speed detecting unit 141 in the DSP 125. The binarized signal is a signal having a pulse-like waveform every time the track is traversed.

The target speed generator 140 is provided with the binarizing circuit 12
One output pulse is counted, and the number of movements of the light beam to the target track is calculated. Then, the target speed generation unit 1
40 is the number of brakes NB, the maximum speed Vmax,
It has information for generating the accelerations A1 and A2, and uses the information to generate a target speed Vref which is a speed profile according to the track pitch of the optical disc 101 as the record carrier and the number of movements to the target track. .

Regarding the method of generating the target speed Vref, in particular, a DVD in which the record carrier has a track pitch of 0.74 μm
Using a disk as an example, a case where the target speed reaches the maximum speed and a case where the target speed does not reach the maximum speed will be described with reference to FIG. FIG.
(A): 1/3 stroke (number of movements: 15270)
FIG. 2B shows a speed profile when performing a search, and a speed profile when performing a short distance (when the target speed does not reach the maximum speed) search.

First, the operation of the target speed generator 140 when performing a 1/3 stroke search in the inner circumferential direction will be described. At the start of the search, the traverse motor 139 starts moving at a constant acceleration A1 in the inner circumferential direction. After a while, | Vref | becomes the set maximum speed Vma
x, the traverse motor 139 is driven at a constant speed Vm
Move with ax. During the search, the number of moves is binarized by the binarization circuit 12.
The target speed Vr is counted using the output pulse signal of 1 until the remaining number of movements becomes equal to or less than the number of brakes NB.
ef generates a constant speed Vmax. When the number of remaining movements becomes equal to or less than the number of brakes NB, the traverse motor 13
9 starts deceleration at a constant acceleration -A1. In addition, |
When Vref | becomes equal to or less than the inclination change speed Vbrk, the acceleration of the traverse motor 139 is changed to -A2 to continue deceleration, and when the number of remaining movements becomes zero, the tracking control is turned on and the generation of the target speed ends. Therefore, Vref
Is the acceleration from A1 to zero, from zero to -A1, from -A1 to-
A2 is generated so as to change.

Next, the operation of the target speed generator 140 when performing a short distance search in the inner circumferential direction will be described. At the start of the search, as in the 1/3 stroke search, Vref which is a constant acceleration A1 is generated, and the traverse motor 139 starts moving in the inner circumferential direction. For short distances, | V
Before ref | reaches the maximum speed Vmax, the number of remaining movements becomes equal to or less than the number of brakes NB, so Vref is generated such that the acceleration changes from A1 to -A1 and from -A1 to -A2. If the number of movements is further reduced as compared to FIG. 2B, | Vref | does not reach the inclination change speed Vbrk, and Vref at this time is generated so that the acceleration changes from A1 to -A2.

A2 is set to a value smaller than A1 in order to reduce fluctuations in the moving speed of the light beam during tracking pull-in and to realize stable tracking pull-in.

The moving speed detector 141 detects the current moving speed V of the light beam from the output pulse of the binarizing circuit 121.
Calculate real. In other words, when the moving speed of the light beam increases, the sinusoidal TE obtained when traversing the track is obtained.
When the signal becomes dense (high frequency) and conversely, the moving speed becomes slow, the TE signal becomes coarse (low frequency), and the current movement becomes larger than the pulse width of the output pulse of the binarization circuit 121 or the pulse interval. The speed Vreal can be obtained.

The differential amplifier 143 has a moving speed Vreal.
And a target speed Vref, and the difference signal is input to the traverse motor drive circuit 138 via the switch 136 and the DA converter 137. The traverse motor 139 is driven by an output signal of the traverse motor drive circuit 138, and is controlled so as to follow the target speed Vref during the search. At this time, the operation performed by the differential amplifier 143 may simply calculate the difference between the input signals. However, if the difference is calculated after appropriately amplifying the two input signals, and the result is output, the higher speed is obtained. And a stable search can be performed.

The differential amplifier 142 has a moving speed Vr
A difference signal between eal and the target speed Vref is output, and this difference signal is input to the tracking drive circuit 131 via the switches 129 and 145 and the DA converter 130. The tracking actuator 132 is driven by an output signal of the tracking drive circuit 131 and is controlled so as to suppress the swing of the converging lens 107 during the search.

The target speed Vref is generated in the target speed generator 140 by the method described above, and the moving speed detector 141 is generated.
Using the difference signal from the output signal of the light beam, the control is performed so that the moving speed of the light beam follows the target speed. In some cases, the speed has not been reduced to a speed that allows retraction. At this time, if the tracking control is forcibly turned ON and the transfer control is performed, the tracking pull-in fails and the worst traverse motor 1
39 may run away. In order to solve this problem, if the moving speed of the light beam at the end of the movement is detected and the tracking actuator 132 is driven so as to decelerate until the moving speed becomes a predetermined value or less (tracking brake processing), Stable tracking pull-in can be realized.

Hereinafter, the tracking brake process will be described in detail with reference to the flowchart of FIG. 3 and the waveform diagram of FIG. FIG. 4 is a waveform diagram from the end of the search to the start of the tracking control. FIG.
4B shows an output signal (track cross signal) of the binarization circuit 121, and FIG. 4C shows a tracking drive (TRD).
A) Waveform.

First, in steps S1 and S2, the tracking actuator 132 and the traverse motor 139 are driven by the number of movements set by the CPU 124 by the above-described search control to move the optical head. Next, in step S3, the tracking actuator 13
2 is temporarily turned off. Further, in step S4, the moving speed Vreal of the optical head at the end of the movement is detected by the moving speed detector 141 from the period T1 of the track cross signal, and is compared with the moving speed Vtron at which stable tracking pull-in is possible. Here, Vtron is determined from the frequency characteristic of the tracking control filter, and the optimum Vtr is determined according to the rotation speed of the optical disc 101.
on is set. When the detected moving speed Vreal is lower than the tracking pull-in speed Vtron,
It is determined that stable tracking pull-in can be performed, and in step S11, the switch 145 is set to the switch 12
9 is set to the output side (default position), and step S1
In step 2, the tracking control is turned on, and the process ends.

If the moving speed Vreal is higher than the tracking pull-in speed Vtron, the switch 145 is set to the output side of the deceleration drive signal generator 144 in step S5, and tracking brake processing is performed. In steps S6 to S10, the predetermined drive value | A |
4, and further generates a value obtained by multiplying the previous drive value by an attenuation constant G (<1) every predetermined time within the same period, and forcibly decelerates by driving the tracking actuator 132. . Here, the drive value A is determined by the type and the number of revolutions of the optical disc 101, and is set to a value that allows efficient deceleration. This tracking brake processing is performed at the detection speed V
By repeating until real reaches the tracking pull-in speed Vtron or less (T2 or more in the cycle), stable tracking pull-in can be realized even under vibration. Here, the tracking pull-in speed Vtro
n is determined by the type and the number of rotations of the optical disc 101, and is set to a value that enables stable tracking pull-in.

In FIG. 4, the cycle is updated every half cycle. However, there is no problem if the cycle is updated every cycle.

(Second Embodiment) Next, a configuration for realizing a high-speed search will be described. The optical disc 101 rotates at a high rotation speed with the increase in the reproduction speed.
When the number of movements to the target track is calculated by the movement number calculation unit 146 in the U124, the optical head is moved via the DSP 125, and the address of the reaching track is acquired, the address of the target track may be passed. This is because after the movement, it takes several ms to confirm whether the tracking has been pulled in the DSP 125, and because it takes time until the address can be read after the tracking is pulled. Although the number of errors due to this is about one or two, an unnecessary search retry occurs, so that the search time until reaching the target address is extended by about 10 ms.

In order to solve this problem, the post-movement address is obtained by correcting the number of moves calculated by the number-of-movements calculation section 146 in consideration of the overhead time by the movement number correction section 147. In this case, the problem of passing the target track can be improved. Hereinafter, this correction processing will be described in detail with reference to the flowchart of FIG.

First, in step S1, the CPU 124
Obtains the address of the track where the optical head is currently located, and calculates the number of movements (N) to the target track by the movement number calculation unit 146 in step S2. Next, in step S3, the number of rotations of the optical disk 101 in the target track (the time required for one rotation is defined as T1) is calculated in the rotation number calculator 148 in the CPU 124 from the CLV value and the reproduction speed. Here, at the time of constant rotation speed reproduction (CLV reproduction), the rotation speed always changes depending on the target track, but constant rotation speed reproduction (CAV reproduction)
At times, even if the target track changes, the number of revolutions is always constant, so if this value is stored in the RAM in the CPU 124, the calculation time can be reduced. Next, in step S4, the above-described overhead time (T0) is compared with T1, and if the overhead time is equal to or more than 回 転 rotation time, the moving number correction in steps S5 to S7 is performed by the moving number correcting unit 147. Specifically, when searching in the inner circumferential direction, (N +
1) When performing a search in the outer peripheral direction, correction is made as (N-1). Then, in step S8, the CPU 124 passes the corrected movement number to the DSP 125, and executes a search. If the overhead time is equal to or shorter than 1/2 rotation time in step S4, the search is executed in step S8 without performing the correction.

By correcting the number of movements in this manner, a high-speed search can be realized without unnecessary search.

Although the first and second embodiments of the present invention have been described above, the present invention is not limited at all by the system for moving the optical head, and includes a gear feed using a DC motor and a linear motor. It can be applied to anything such as a method using a stepping motor (linear pulse motor) and the like. As a method for detecting a TE signal, there are a push-pull method, a three-beam method, and the like in addition to the phase difference method as in the present embodiment, and the present invention can be applied to any detection method.
There is no limitation.

(Third Embodiment) Next, a third embodiment will be described. FIG. 5 is a block diagram showing a configuration of an optical recording / reproducing apparatus according to a third embodiment of the present invention. Parts corresponding to those in the first embodiment are denoted by the same reference numerals. Then, the description is omitted.

The third embodiment is an optical recording / reproducing apparatus for reproducing the optical disk 201 having the individual information recording area shown in FIG. 6, and has the same structure as that of the first embodiment shown in FIG. This can be realized by adding a dropout detection unit 202 that detects a loss of a reproduction signal due to a scratch or the like on 201.

In the individual information recording area of the optical disk 201 shown in FIG. 6, information different for each optical disk such as identification information such as an ID number and an encryption key is recorded. In this recording, a YAG laser (wavelength: 1064 nm) is irradiated on the reflection film of a normal optical disk, and the stripe obtained by removing the reflection film in a radially elongated shape (10 μm width) is formed into a bar code along the circumference according to the recording information. This is done by arranging them.

In the individual information recording area, since the reflection film is removed as described above and most of the light is transmitted, the amount of reflected light drops to near zero level as shown in FIG. A signal waveform having a larger amplitude and a longer cycle can be obtained as compared with a signal obtained by reproducing a pit. Therefore, in the individual information recording area, the address cannot be read by the address reading circuit 123, and a search cannot be performed in the individual information recording area by a normal search method.

The stripes arranged in the form of a bar code have the reflection film removed therefrom, and the amount of reflected light is reduced. Therefore, it can be regarded as equivalent to a very large flaw. for that reason,
In the individual information recording area, a dropout detection unit 2 for detecting a defect of a reproduction signal due to a scratch on the optical disk 201 or the like.
02 is as shown in FIG. 7B. The output signal of the dropout detection unit 202 is input to the DSP 125, and the DSP 125 recognizes that the section where this signal is high is the dropout unit.
By utilizing this, it is possible to regard that the optical head is present in the individual information recording area by the DSP 125 detecting the dropout.

Hereinafter, a method of searching the individual information recording area will be described with reference to the flowchart of FIG.

First, in step S1, a search is performed up to the track before the individual information recording area. Since the search method at this time is the same as that of the first embodiment, the description is omitted here. Next, in step S2, the detection width of the dropout detection unit is set. This is to prevent a normal flaw (about 1 μm width) from being detected because the interval between stripes arranged on the barcode is about 10 μm. Further, in step S3, the tracking control is turned off. This is because, in the individual information recording area, the address cannot be read as described above, and a sufficient TE signal cannot be obtained due to a reduced amount of reflected light, and tracking control becomes unstable.

In step S4, a predetermined time (about 3 m
s) The traverse motor 139 is driven toward the individual information recording area to move the optical head. After the movement, in step S5, it is determined whether a dropout signal has been detected. If the dropout signal has been detected, it can be determined that an optical head is present in the individual information recording area, and the process ends. If the dropout signal is not detected, the traverse motor 139 is driven again in step S4,
Steps S4 and S5 are repeated until a dropout signal is detected in step S5.

In the method described above, it is possible to surely move to the individual information recording area. However, as another configuration, a method of moving by utilizing the fact that tracking control becomes unstable in the individual information recording area is used. Will be described below with reference to FIG.

(Fourth Embodiment) FIG. 9 is a block diagram showing a configuration of an optical recording / reproducing apparatus using track flow detection. The same parts as those in the first embodiment are identical to those in the first embodiment. The reference numerals are attached and the description is omitted here.

This is because the output signal (track cross signal) of the binarization circuit 121 which binarizes the TE signal is converted to the DSP 12
5 can be realized by inputting not only to the target speed generator 140 and the moving speed detector 141 but also to the track flow detector 301.

The track flow detector 301 receives a low-level signal when tracking control is normally performed. Further, the binarized signal can be counted by detecting the edge of the track cross signal. When tracking control is deviated due to vibration or the like, a track cross signal is input to the track flow detecting unit 301.
By counting the number of track cross signals equal to or more than a predetermined number (5) within ms), it is possible to detect that a track flow has occurred.

As described above, in the individual information recording area,
Since the reflected light amount is low, a sufficient TE signal cannot be obtained, the tracking control becomes unstable, and a track flow occurs. By using this, DSP125
Has detected the track flow, it can be regarded that the optical head is present in the individual information recording area.

Hereinafter, a method for searching the individual information recording area using the track flow detection will be described with reference to the flowchart of FIG.

First, as in the case of using dropout detection in step S1, a search is performed up to the track before the individual information recording area. Since the search method at this time is the same as that of the first embodiment, the description is omitted here. Next, in step S2, the tracking control is turned off, and in step S3, a predetermined time (about 3 m
s) The traverse motor 139 is driven toward the individual information recording area to move the optical head. After the movement, the tracking control is turned on in step S4. Next, in step S5, it is determined whether or not a track flow is detected. If the track flow is detected, it can be determined that an optical head is present in the individual information recording area, and the process ends. If the track flow is not detected, the traverse motor 139 is driven again in step S3, and steps S3 and S3 are performed until the track flow is detected in step S5.
4. Repeat S5.

In the method described above, it is possible to reliably move to the individual information recording area as in the case of using the dropout signal.

In the present embodiment, the input to the track flow detecting section 301 has been described as a signal obtained by binarizing the TE signal (track cross signal). However, the reproduction signal (RF signal) or the envelope of the RF signal has been described. A similar effect can be obtained even if a signal (off-track signal) obtained by binarizing the drop detection signal at a predetermined level is input to the track flow detection unit 301 and the track flow is detected.

(Fifth Embodiment) Next, a fifth embodiment will be described with reference to the block diagram of FIG. 11 in addition to the block diagram of FIG. FIG. 11 shows the reproduction signal (R
PLL for generating binary synchronization data from F signal)
It is a block diagram of a control part, and the part corresponding to 1st Embodiment attaches | subjects the same reference code, and abbreviate | omits description here.

The RF signal output from the summing amplifier 122 is input to an automatic gain controller (AGC) 401 to absorb variations in the optical disk 101 and the optical head and a decrease in the amount of light due to dust and fingerprints, and adjust the amplitude to a constant value. Then, the signal is input to an equalizer 402 having a function of removing high-frequency noise outside the RF signal band and boosting a high-frequency component of the RF signal whose amplitude is extremely reduced due to code interference. Note that the equalizer 402 is controlled by the equalizer characteristic control unit 403 so that the cutoff frequency (FC) of the RF signal is
And the amount of boost (BOOST) can be set freely, so that the optimum R
An F signal can be obtained. The RF signal (EQRF signal) waveform-equalized by the equalizer 402 is input to the data slicer 404, and is compared with a threshold level so that the duty after binarization becomes equal, and is converted into a binarized signal (DSRF signal). Is converted.

The DSRF signal is input to a PLL control loop for synchronizing with the reproduction clock.
The control loop generally includes two control loops, a phase control loop used during reproduction and a frequency control loop used when tracking control such as during search is off.
Switching between these two control loops is performed by switches 406 and 4
11, the switch 406 is turned on and the switch 411 is set to the off position during the phase control, and the switch 406 is set to the off position and the switch 411 is set to the frequency control during the frequency control.

First, a phase control loop used during reproduction will be described. The phase control loop includes a phase comparator 40
5. a switch 406 for switching on / off the phase control loop, an amplifier 407 for determining the gain of the control loop,
A feedback loop is formed by the VCO 408 and a frequency divider 409 for dividing the oscillation frequency of the VCO 408, and controls the phase of the DSRF signal so as to synchronize with the reproduced clock.

The frequency control loop used when the tracking control is off, such as during a search, includes a frequency comparator 410, a switch 411 for switching the frequency control loop on / off, an amplifier 407, a VCO 408, and a frequency divider 4
09 forms a feedback loop,
The frequency of the DSRF signal is controlled so as to synchronize with the reproduction clock.

At the time of searching using the two control loops described above, first, the PLL is pulled into the target frequency in the frequency control loop, and after pulling in to the target frequency, the phase control loop is turned on to realize PLL control.

However, at the time of constant rotation speed reproduction (CAV reproduction), the reproduction speed changes depending on the position of the optical head. Therefore, the frequency characteristics of the equalizer 402, the loop gain of the PLL control loop, and the oscillation frequency are not always optimal at the reproduction position. Therefore, not only does the accuracy of reading the address and data deteriorate, but also the worst case is that the PLL is not locked. A method for solving this problem will be described below with reference to the flowchart in FIG.

The CPU 124 has a table of the optimal FC and BOOST corresponding to the reproduction speed, a table of the loop gain of the PLL control loop, and a table of the frequency division ratio N of the frequency divider 409. When performing a search, first, step S
In step 1, the address of the track where the optical head is currently located is acquired. Next, in step S2, the reproduction speed after the search is calculated from the rotation speed of the disk motor 102 and the position of the optical head at the target address. Further, in step S3, the optimum equalizer 402 at the target address is obtained from the table stored in the CPU 124.
Are taken out, and the equalizer 402 is set in the equalizer characteristic control unit 403. Similarly, in step S4, the optimum PLL setting value is extracted and the PLL
The control loop gain 407 and the frequency divider 409 are set. Next, in steps S5 and S6, the optical head is moved until the target track is reached, and the search ends.

As described above, at the time of searching, the optimum equalizer and PLL at the target address are set before the optical head is moved, so that a stable and high-speed PL is set.
The L pull-in and address / data read performance can be ensured.

The method for moving the optical head may be the method described in the first embodiment, but the present embodiment is not limited to the method for moving the optical head.

While the CAV playback has been described above,
If the followability of the disk motor 102 is poor even during constant speed reproduction (CLV reproduction), the above-described problem occurs because the rotation speed of the disk motor 102 does not reach the target rotation speed in the target track at the end of the search. Also in this case, if the apparatus is configured to input information to the CPU 124 so that the number of rotations of the disk motor 102 can be understood,
At the end of the search, the current rotation speed of the disk motor 102 is obtained, and the equalizer 402 and the PLL control loop are set in accordance with the playback speed calculated from the rotation speed. It is possible to secure the pull-in and address / data read performance.

[0076]

As described above, according to the present invention, the moving speed of the optical head at the end of the search is detected, and when the moving speed is high, the tracking actuator is forcibly driven in the deceleration direction to thereby reduce the vibration. It is possible to provide an optical recording / reproducing apparatus having stable tracking pull-in performance even below.

Further, by correcting the number of movements in consideration of the tracking pull-in confirmation time at the end of the search and the time required to read the address, an optical device having a high-speed search performance without unnecessary search retries. A type recording / reproducing apparatus can be provided.

Further, by detecting the dropout signal of the reproduction signal or detecting the track flow, it is possible to reliably perform the search even in the individual information recording area which cannot be searched by the normal search control. An optical recording / reproducing device can be provided.

Further, at the start of the search, the equalizer characteristics are switched so that an optimum reproduction signal is obtained in the target track, and the PLL clock is switched in accordance with the reproduction speed in the target track so that the PLL is locked at a high speed. An optical recording / reproducing device capable of performing stable data reproduction can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an optical recording / reproducing apparatus according to a first embodiment of the present invention.

FIG. 2 is a characteristic diagram showing characteristics of a speed profile in the embodiment.

FIG. 3 is a flowchart of a tracking brake process in the embodiment.

FIG. 4 is a relationship diagram of a TE signal, a binarized signal, and a tracking drive waveform in the tracking brake process according to the embodiment.

FIG. 5 is a block diagram showing a configuration of an optical recording / reproducing apparatus according to a third embodiment of the present invention.

FIG. 6 is an external view of an optical disc having an individual information recording area according to the embodiment.

FIG. 7 is a diagram showing R in an individual information recording area according to the embodiment;
Diagram of relationship between F signal and dropout signal

FIG. 8 is a flowchart for moving to an individual information recording area using a dropout signal according to the embodiment;

FIG. 9 is a block diagram illustrating a configuration of an optical recording / reproducing apparatus according to a fourth embodiment of the present invention.

FIG. 10 is a flowchart for moving to an individual information recording area using tracking flow detection according to the embodiment;

FIG. 11 is a block diagram showing a configuration of an optical recording / reproducing apparatus according to a fifth embodiment of the present invention.

FIG. 12 is a flowchart showing the flow of processing according to the embodiment;

FIG. 13 is a flowchart showing the flow of processing according to the second embodiment of the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Optical disk 102 Disk motor 103 Light source of semiconductor laser etc. 104 Coupling lens 105 Polarization beam splitter 106 Polarizer 107 Convergence lens 108 Condensing lens 109 Quadrant photodetector 110 Preamplifier 111 Preamplifier 112 Preamplifier 113 Preamplifier 114 Addition amplifier 115 Addition amplifier 116 Comparator 117 Comparator 118 Phase comparator 119 Differential amplifier 120 Gain switching circuit 121 Binarization circuit 122 Addition amplifier 123 Address reading circuit 124 CPU 125 DSP 126 AD converter 127 Phase compensation filter 128 Gain switching circuit 129 Switch 130 DA converter 131 Tracking drive Circuit 132 Tracking actuator 133 Low-pass filter 134th Phase compensation filter 135 Gain switching circuit 136 Switch 137 D / A converter 138 Traverse motor drive circuit 139 Traverse motor 140 Target speed generator 141 Moving speed detector 142 Differential amplifier 143 Differential amplifier 144 Deceleration drive signal generator 145 Switch 146 Movement number Calculation unit 147 Movement number correction unit 148 Rotation speed calculation unit

 ──────────────────────────────────────────────────続 き Continued from the front page (72) Inventor Mitsuro Moriya 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (15)

[Claims] 1. A light beam converging means for converging and irradiating a light beam on a record carrier; a first moving means for moving the light beam convergent means in a direction crossing a track on the record carrier;
A track shift detecting means for generating a signal corresponding to the positional relationship between the light beam and the track, and the first moving means is driven in accordance with a signal from the track shift detecting means so that the light beam scans on the track. Tracking control means for controlling the light beam converging means, a second moving means for moving a light beam in a direction crossing a track on a record carrier, and the first or second moving means. Search control means for driving and moving the light beam to a desired track, moving speed detecting means for detecting the speed of the moving light beam by the search control means, and at the end of the movement detected by the moving speed detecting means Adding a deceleration signal synchronized to the speed detection cycle of the moving speed detecting means to the first moving means until the moving speed of the light beam becomes equal to or less than a predetermined value. Optical recording and reproducing apparatus, characterized in that it comprises means. The moving speed detecting means includes a binarizing means for binarizing a signal of the track deviation detecting means, and a period detecting means for detecting a period of the signal of the binarizing means, and the decelerating means includes a first detecting means.
2. The optical recording / reproducing apparatus according to claim 1, wherein a deceleration signal applied to said moving means is variable every one cycle or one half cycle of said cycle detecting means. 3. A rotation means for rotating a record carrier, and rotation control means for controlling the rotation means to a predetermined rotation speed, wherein a deceleration signal is generated according to the rotation speed controlled by the rotation control means. 2. The optical recording / reproducing apparatus according to claim 1, wherein the moving speed of the light beam or the magnitude of the generated deceleration signal is switched. 4. The apparatus according to claim 1, wherein the moving speed of the light beam capable of generating the deceleration signal or the magnitude of the generated deceleration signal is switched in accordance with the type of the loaded record carrier. Optical recording and reproducing device. 5. A search control means for moving a light beam to a desired track across a track on a rotating record carrier, and acquiring position information on a current track to determine the number of movements to the desired track. Movement number calculation means to calculate, the movement number calculated by the movement number calculation means,
Command means for instructing the search control means, and estimating means for estimating a time required for acquisition processing of position information on a desired track, and a command value of the command means based on the processing time estimated by the estimating means. And an optical recording / reproducing apparatus configured to operate the search control means. 6. A search control means for moving a light beam to a desired track across a rotating track on a record carrier, and obtaining position information on a current track to determine the number of movements to the desired track. Movement number calculation means to calculate, the movement number calculated by the movement number calculation means,
Command means for commanding the search control means, rotation number measuring means for measuring the number of rotations of the record carrier in the current track, and rotation number calculating means for calculating the number of rotations in the desired track, the rotation number The command value of the command means is corrected based on the number of revolutions in the current track measured by the measuring means and the number of revolutions in the desired track calculated by the number of revolutions calculating means, and the search control means is operated. An optical recording / reproducing apparatus characterized by comprising. 7. A light beam is converged on a record carrier having an individual information recording area in which information such as identification information and an encryption key, which is different for each sheet, is arranged and recorded along a part of the circumference of the record carrier. A light beam converging means for irradiating, and a first means for moving the light beam converging means in a direction crossing a track on a record carrier.
Moving means, a track shift detecting means for generating a signal corresponding to the positional relationship between the light beam and the track, and driving the first moving means in accordance with a signal from the track shift detecting means, so that the light beam Tracking control means for controlling the light beam to scan above, second moving means for moving the light beam in a direction crossing the track on the record carrier by moving the light beam converging means, Search control means for driving the second moving means to move the light beam to a desired track across a plurality of tracks, dropout detecting means for detecting a lack of a reproduced signal due to a flaw or the like, and said dropout detection An optical disc drive having an individual information recording area discriminating means for discriminating that the light beam has moved to the individual information recording area in accordance with a signal of the means. Reproducing apparatus. 8. A light beam is converged on a record carrier having an individual information recording area in which information such as identification information and an encryption key, which is different for each sheet, is arranged and recorded along a part of the circumference of the record carrier. A light beam converging means for irradiating, and a first means for moving the light beam converging means in a direction crossing a track on a record carrier.
Moving means, a track shift detecting means for generating a signal corresponding to the positional relationship between the light beam and the track, and driving the first moving means in accordance with a signal from the track shift detecting means, so that the light beam Tracking control means for controlling to scan on the top, second movement means for moving the light beam in a direction crossing the track on the record carrier by moving the light beam converging means, and a plurality of tracks. Search control means for traversing and moving the light beam to a desired track; track jump detection means for detecting that the light beam scanning on the track has deviated from the track; An optical recording / reproducing apparatus, comprising: an individual information recording area discriminating means for judging that the device has moved to an individual information recording area. 9. The detection level of the dropout detection means is as follows:
8. The optical recording / reproducing apparatus according to claim 7, wherein switching is performed between a case where it is determined that the light beam has moved to the individual information recording area and a case where a flaw on the record carrier is detected. 10. The track jump detecting means includes a binarizing means for binarizing a signal of the track deviation detecting means, and a measuring means for counting output pulses of the binarizing means, and the measuring means for a predetermined time. 9. The optical recording / reproducing apparatus according to claim 8, wherein it is configured to determine that the light beam has moved to the individual information recording area based on the measurement result. 11. A track jump detecting means comprising: a binarizing means for binarizing an envelope detection signal of a reproduction signal or a total light amount signal from a record carrier at a predetermined level; and an output pulse of the binarizing means. 9. The optical recording / reproducing apparatus according to claim 8, wherein the optical recording / reproducing apparatus is constituted by measuring means for counting, and judging that the light beam has moved to the individual information recording area based on a measurement result of the measuring means for a predetermined time. 12. Retrieval control means for moving a light beam to a desired track across a plurality of tracks, reproduction signal detection means for generating a reproduction signal by reflected light or transmitted light from a record carrier; A boost switching means for changing the amount of amplification of a high frequency component in a signal band with respect to a signal of the signal detection means, and a cutoff switching means for switching a cutoff frequency of a filter for removing high frequency noise outside the signal band. An optical recording / reproducing apparatus comprising: a waveform equalizing unit; wherein the search control unit sets the boost switching unit and the cutoff switching unit in accordance with a track position where a light beam moves. 13. The optical recording apparatus according to claim 12, wherein the setting of the boost switching means and the cutoff switching means is set according to a predetermined rotation speed calculated from a track position where the light beam moves. Playback device. 14. A counting means for counting information tracks on a record carrier traversed by a light beam, a retrieval control means for moving a light beam to a desired track based on the count value of said counting means, Reproduction signal detecting means for generating a signal for reproducing information on a record carrier by reflected light or transmitted light;
Binarizing means for converting a value, a synchronous clock generating means for outputting a frequency-variable synchronous clock in accordance with the frequency of the signal from the binarizing means, and a clock output from the synchronous clock generating means having a predetermined frequency. Frequency control means for controlling the synchronous clock generation means so that the search control means searches for a desired target track in order to reproduce desired information on a record carrier. An optical recording / reproducing apparatus characterized in that the target frequency of the frequency control means is switched based on the following. 15. The apparatus according to claim 15, wherein the target position of the frequency control means is set in accordance with the rotational speed of the record carrier calculated from the track on which the light beam is located, which is obtained from the count value. The optical recording / reproducing apparatus according to claim 14.