JPH02304778A - Optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To enable a stable tracking operation even in a sample servo method by conjecturing the time of a nonsampling period and sample data at this time with a previous sample data value and a present sample data value and control ling a tracking device accordingly. CONSTITUTION:A tracking error signal is extracted by a control signal (b) of a reference clock generating circuit 2 and fetched by an A/D converter 8, and hence an acceleration/deceleration pulse changeover of a jump pulse genera tor 10 is performed by a control signal (d). Then, a zero cross points is conjec tured based on an A/D value fetched every reference clock, and an acceleration/ deceleration changeover point of a jump pulse is settled. Thus, a tracking drive means (actuator) 13 is controlled by conjecturing the time of a nonsampling period and a sample data at that time. By this method, even in the case of the sample servo method, the operation can be stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical information recording/reproducing device, and particularly an optical information recording/reproducing device in which a tracking servo area and a data area are arranged spatially separately on a track, The present invention also relates to an optical information recording/reproducing device for an optical information recording medium in which the tracking servo areas are arranged on the track at regular intervals.

[Prior Art] Devices that record or reproduce signals using laser light have been put to practical use. For example, there are CDs (Continuous Discs), LDs (Laser Discs), and the like. In addition, information signals are optically recorded by projecting a light beam onto a disk-shaped recording medium (hereinafter referred to as a disk) that can be recorded, reproduced, and erased using magneto-optical signals on predetermined spiral or concentric tracks. Magneto-optical disk devices for reproducing and erasing information are also being developed.

Typically, to read information signals from these disks,
The pits are read by projecting a light beam onto the disk and optically scanning the desired track.By the way, as a tracking control method when optically scanning a track in this way, there are continuous servo method and sample Sir is law.

The former is a method that constantly monitors the deviation of the trunk and feeds back the error from the target value to apply the servo, while the latter is a method that monitors the deviation of the truck for a certain period of time, for example about 10μlee.
Alternatively, the servo area that appears every 20 μsec is sampled and monitored, and the error with the target value is feed-punked to apply the servo. In recent years, the latter sample servo method has been increasingly used because of its scratch-resistant servo section and data section, which can be spatially separated and have the advantage of no crosstalk.

[Problems to be Solved by the Invention] However, in the sample servo method, when the servo loop is closed, the deviation does not change significantly, so it is not a problem to hold the track error data for 10 μsec or 20 μmacO. However, in situations where sample data changes rapidly, such as during a track jump, there is a problem that the sample dead time affects the operation and makes the operation unstable. Especially during a single jump, when using continuous sir, after applying an acceleration pulse, when the center of the track and the adjacent track is detected, it immediately switches to deceleration and acceleration, and jumps when the next track is reached. It is possible to use a method in which the pulse application is stopped and the servo is closed, but if similar control is performed using the sample servo method, the center of the track and the adjacent track can be detected as shown in Figure 2 (Shu). In this case, depending on the sampling timing, a time delay of the maximum sampling time interval occurs, and the acceleration pulse is applied during this time delay, resulting in instability of the single jump.

For example, if you perform a track jump with an acceleration/deceleration of approximately 5G, the time to pass half of a track with a pitch of 1.6μm, that is, 0.8μm, will be approximately 180μsec, but considering that the sampling time is 20μ116e extra, the acceleration will be increased. Therefore, more than 20% of the desired truck will pass by.

[Means for Solving the Problems] The optical information recording/reproducing device of the present invention is characterized in that a tracking servo area and a data area are spatially separated from each other in a track, and the tracking servo area is In an optical information recording/reproducing device for an optical information recording medium arranged on the track at regular intervals, sample data obtained in a desired tracking servo area and tracking before the desired tracking servo area. The present invention is characterized in that the time and the sample data at that time during the non-sampling period are estimated using the sample data obtained in the servo area, and the tracking drive means is controlled based on the estimated value.

[Function] The optical information recording/reproducing device of the present invention combines sample data obtained in a desired tracking servo area and sample data obtained in a tracking servo area υ before the desired tracking servo area. By estimating the time and the sample data at that time during the non-sampling period using the sample data, and controlling the tracking drive means based on the estimated value, even when there is a large change in the sampling value, , it is possible to control the tracking drive means during a non-sampling period.

[Example] Hereinafter, the optical information recording/reproducing apparatus of the present invention will be described in detail based on a specific example using the drawings.

FIG. 1 is a block diagram of a tracking servo system of an optical information recording/reproducing apparatus according to the present invention.

In the figure, a sensor 1 uses a laser beam to detect the amount of deviation of the disk 14 from the track guide groove as a tracking error signal. However, as shown in Figure 3,
The configuration of the disk 14 is to serve pie at regular intervals) 15
-1. Data bytes 15-b are lined up, and a tracking error signal is extracted from a predetermined location on the serve byte 15-a. It is the clock generation circuit 2 that generates a clock for notifying that sampling is possible for each predetermined location. A sampling switch 3 and a capacitor 4 form a sample hold circuit, and the control signal of the reference clock generation circuit 2 closes the switch 3 when sampling is possible to extract a tracking error signal. The tracking error signal is amplified to a target gain by an amplifier circuit 5, and compensated by a phase compensation circuit 6 to obtain a target phase margin. The loop switch 7 is a switch that opens and closes the tracking servo loop, and is left open during track jumps. The drive circuit 12 is for driving the actuator 13 in a direction that reduces the target deviation using the tracking error signal, and serves when the loop switch 7 is closed.C
PU 9 is a processor that controls the aforementioned serve system,
The tracking error signal is input to the converter 8, and the loop switch 7 is turned on by the control signal d.
, OFF control is performed to switch the jump pulse generator 10 (acceleration, deceleration) sharpness, and the jump/4 pulse generator 10 is turned ON and OFF by the control signal f.
It is in charge of control. The track Zo Young switch 11 switches the output pulse from the jump pulse generator 10 to
N, OFF control is performed, and a jump pulse is applied to the drive circuit 12 at a predetermined timing.

FIGS. 2A to 2C are timing charts for explaining the operation of the optical information recording and reproducing apparatus.

The tracking servo is opened by turning off the servo loop switch 7 with the control signal d shown in FIG. 2 (CD), and the track jump switch 11 is turned on with the control signal e shown in FIG. 2 (CD). Then, when a jump pulse is applied to the drive circuit 12, a single jump is started.

The waveform shown in FIG. 2(A) is the tracking error signal at that time, and this tracking error signal is the 21st W.
The control signal from the reference clock generation circuit 2 shown in (B) was obtained by turning on the sampling switch 3 and sample-holding the tracking error signal obtained from the υ surge detector using the sample and hold circuit. It is.

Also, at the same time, the values taken four times from the reference will be the values shown in Figure 2 (a).Here, the center of the track and the adjacent track can be obtained as a zero-cross signal, but the sample-and-hold signal can be obtained as it is at the zero-cross signal.・Separated by comparator
If it is too long, the maximum delay will be the sample time, making single jumps unstable. Therefore, in the present invention, the zero-crossing point is estimated based on the value to be acquired for each reference clock, and the jump pulse acceleration/deceleration switching point is set. Figure 2 (as shown in Q, (time, A/1: value) just before zero crossing is (t, ,
B), and (time, A/ill value) from time 1B to sample time tI 1 second before (t, , A
), the desired zero-crossing time tc = X
When the track A-B of the adjacent track reaches the sand diameter B, it is sufficient to switch between acceleration and deceleration at that time. The output of the drive circuit 12 at that time is shown in Figure 2 (1
The output signal g is as shown in 1.

In the embodiment described above, acceleration and deceleration were switched at the center of the truck and the adjacent truck, but the drive circuit.

Taking into account delays such as the start-up of the coil, switching may be performed a certain period of time in advance to reach the center of the adjacent track.

Furthermore, in the above embodiment, the CPU takes in the φ value and calculates the zero crossing point, but digital
A signal processor (DSP) may also be used.

Furthermore, in the embodiment described above, the zero-crossing point was estimated digitally, but it is also conceivable to create an analog waveform that converges on the sample point and input it into a constrictor to estimate the zero-crossing point.

Note that the present invention can be used not only for switching between acceleration and deceleration of the tracking actuator during a track jump, but also for switching between opening and closing of a servo loop. For example, by estimating the time at which sample data will be obtained when a predetermined position (for example, the center of the track) of a desired track is reached, and closing the servo loop of the tracking drive means at that time, the track pull-in operation can be stabilized. It can be done by

[Effects of the Invention] As explained above, according to the optical information recording/reproducing apparatus of the present invention, even when there is a large change in sample data, for example, during a single track jump, the previous sample data value and the current sample data value can be From the sample data value, the time and the sample data at that time during the non-sampling period are estimated, and the tracking drive means is controlled based on the estimated value, so that stable tracking operation can be achieved even in the sample servo method. It can be made possible.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a tracking serge system of an optical information recording/reproducing apparatus according to the present invention. FIGS. 2(A) to 2(F) are timing charts for explaining the operation of the optical information recording/reproducing apparatus. FIG. 3 is an explanatory diagram of an optical information recording medium used in Sandelser's method. DESCRIPTION OF SYMBOLS 1... Ser is a detector, 2... Reference clock generation circuit, 3... Sampling switch, 4... Capacitor, 5... Amplifying circuit, 6... Phase compensation circuit, 7...
...Loop switch, 8-...Friend Φ converter, 9...
-CPU. DESCRIPTION OF SYMBOLS 10... Jump pulse generator, 11... Track jump switch, 12... Drive circuit, 13-... Actuator. Agent: Patent Attorney Johei Yamashita, Figure 2, 7,

Claims (3)

[Claims] (1) An optical information recording medium in which a tracking servo area and a data area are arranged spatially separately on a track, and the tracking servo areas are arranged on the track at regular intervals. In a digital information recording and reproducing device, sample data obtained in a desired tracking servo area and sample data obtained in a tracking servo area before the desired tracking servo area are used to generate data during a non-sampling period. An optical information recording/reproducing device characterized in that it estimates a time and sample data of that time, and controls a tracking drive means based on the estimated value. (2) Estimate the time at which sample data will be obtained when the optical system that irradiates the optical information recording medium with a light beam reaches a predetermined position between a track and an adjacent track during a track jump, and Claim 1: The tracking drive means is switched between acceleration and deceleration at a given time.
The optical information recording/reproducing device described above. (3) At the time of track jumping, estimate the time at which sample data will be obtained when the optical system that irradiates the optical information recording medium with a light beam reaches a predetermined position on the desired track, and at that time the tracking drive 2. An optical information recording and reproducing apparatus according to claim 1, wherein the servo loop of the means is closed.