JPH04321981A - Optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To obtain the optical information recording and reproducing device in which an optical head is prevented from crashing against the main body of the device, even when the optical head runaway, and capable of quickly and surely restoring to a prescribed control. CONSTITUTION:The device is comprised of a runaway detection circuit 28 which detects the runaway of a tracking actuator 6 by means of a circuit 7 for detecting the position of an objective lens and the runaway detection circuit 27 which detects the runaway of a linear actuator by the output of a driving amplifier. Based on the signals from these runaway detection circuits 27, 28, a dumping signal generating circuit 25, which generates a dumping signal, a driving signal of a level that generates a maximum acceleration on the linear actuator 8 to a speed reducing direction, is controlled by a controller 29 in order to control the runaway, the maximum acceleration is generated on the linear actuator 8 to the speed reducing direction, and the runaway is controlled.

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 recording, reproducing, or erasing information on an information recording medium having a large number of tracks.

0002

2. Description of the Related Art In recent years, information has been recorded on an optical information recording medium, such as an optical disk, by irradiating it with a positioned and minutely focused light beam, or by using the return light of this light beam. An optical information recording/reproducing device that can reproduce recorded information by detecting the information has been developed.

[0003] In such an optical information recording/reproducing device, when the position control is lost due to an impact from outside the device while controlling the position of the light spot irradiated from the optical head onto the optical disk, or immediately after a seek operation. If the optical spot fails to be brought into position control, conventionally, as shown in Japanese Patent Application Laid-Open No. 64-4986, the track crossing speed of the optical spot is controlled to a speed that allows the optical spot to be brought into position control. This is used to control the position of the light spot.

0004

[Problems to be Solved by the Invention] However, in the optical information recording/reproducing device disclosed in Japanese Patent Application Laid-Open No. 64-4986, runaway occurs near the outermost or innermost track, and the initial speed at the time of runaway is low. If this is large, sufficient speed damping cannot be applied, causing problems such as the optical head colliding with the main body of the optical information recording/reproducing apparatus, causing the focus servo to become disconnected, and requiring a long processing time to recover. Furthermore, there is a possibility that the optical head may be damaged by the impact.

The present invention has been made in view of the above circumstances, and is intended to prevent the optical head from colliding with the main body of the optical information recording/reproducing apparatus when the optical head runs out of control, and to quickly adjust the focus servo or other predetermined functions. It is an object of the present invention to provide an optical information recording/reproducing device that can return to control.

[0006]

[Means for Solving the Problems] The optical information recording/reproducing apparatus of the present invention has an optical system that forms a light spot on a track provided on an information recording medium, and the light spot allows information to be recorded on the information recording medium. an optical head for recording, reproducing, or erasing; an optical head driving means for driving the optical head in a track-crossing direction; a tracking control means for causing the tip of the optical head to follow the center of the track; speed detection means for detecting the relative speed of the optical spot with respect to the track based on a tracking error signal; position detection means for detecting the relative position of the optical system with respect to the optical head driving means; when the optical head runs out of control; It has a runaway detection means for detecting this runaway state, a position control means for controlling the light spot to follow a predetermined track, and a speed control means for controlling the speed of the light spot based on the output of the speed detection means. The optical recording/reproducing apparatus includes damping means for decelerating the optical head at a maximum acceleration by the runaway detection means.

[0007]

[Operation] After the damping means decelerates the optical head at the maximum acceleration and the speed of the optical head becomes a speed controllable speed, the speed control means changes the speed of the optical head to a position controllable speed. and the position is controlled by the position control means.

[0008]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1 to 6 relate to one embodiment of the present invention, with FIG. 1 being a block diagram showing the configuration of an optical information recording/reproducing device, and FIG. 2 being a block diagram showing a runaway detection circuit for detecting runaway of a tracking actuator. FIG. 3 is a timing diagram illustrating the operation of the runaway detection circuit shown in FIG. 2. FIG. 4 is a block diagram showing the configuration of the runaway detection circuit that detects runaway of the linear actuator. FIG. 6 is a timing diagram explaining the operation of the runaway detection circuit shown in FIG. 4.
FIG. 2 is an explanatory diagram illustrating how the speed of the optical head is controlled.

The optical information recording/reproducing apparatus of the present invention is shown in FIG.
As shown in FIG. 1, for example, an optical disc 1 is inserted through an insertion slot (not shown) and is removably disposed at a predetermined position.
It includes a spindle motor 2 that rotates the optical disc 1 and an optical head 4 that irradiates the optical disc 1 with a light beam.

The optical head 4 focuses a light beam onto a track (not shown) on the optical disk 1 and forms a light spot 3.
A tracking actuator 6 is equipped with an objective lens system 3 forming an optical disc 3, a linear actuator 8 moves the optical disc 1 in the radial direction of the optical disc 4 on the main body 22 of the optical information recording and reproducing apparatus, and the tracking actuator 6 moves the optical disc 1 to a desired track position. an objective lens position detection unit 7 that generates a detection signal indicating the relative positional displacement between the objective lens system 3 and the linear actuator 8 that have moved; and a photodetector 5 that detects reflected light of the light beam irradiated onto the optical disc. It is equipped with

Although not shown, the optical information recording and reproducing apparatus includes a light source that supplies a light beam, an optical system that guides the light beam from the light source to the objective lens system 3, and a system that detects the reflected light. It is equipped with an optical system that guides the light to the vessel 5.

The optical information recording and reproducing apparatus further includes a total reflected light amount signal detection circuit 9 that generates a total reflected light amount signal from the reflected light detected by the photodetector 5, and a total reflected light amount signal detection circuit 9 that generates a tracking error signal from this reflected light. By comparing the phases of the total reflected light amount signal and the tracking error signal with the tracking error signal detection circuit 10, the moving direction of the light beam is detected, for example, as shown in Japanese Unexamined Patent Publication No. 198036/1989. A detection circuit 11, an off-track detection circuit 12 that detects that tracking control has been lost due to a tracking error signal, and a track pulse count circuit 1 that counts tracking error signals.
3, and a controller 29 that performs drive control of the tracking actuator 6 and the linear actuator 8.

When position control is performed to cause the light spot 33 to follow a track on the optical disk 1, the objective lens position indicating the relative positional displacement between the objective lens system 3 and the linear actuator 8 generated by the objective lens position detection section 7 is used. The detection signal is used in order to cause the optical head 4 to follow the objective lens system 3 by the linear actuator 8, for example, as described in Japanese Patent Laid-Open No. 5
The signal is input to the objective lens phase correction circuit 24 as shown in Japanese Patent No. 8-91536, and is input to the drive amplifier 26 that drives the linear actuator 8 via the SW 32 under the control of the controller 29, and is fed back to the linear actuator 8.

Further, in order to cause the objective lens system 3 to follow the track by the tracking actuator 6, the tracking error signal is input to the track phase correction circuit 34, and is sent to the drive amplifier by the adder 20 via the SW 30 under the control of the controller 29. The outputs of 26 are added together, input to a drive amplifier 21 that drives the tracking actuator 6, and fed back to the tracking actuator 6. Here, the reason why the output of the drive amplifier 26 is added by the adder 20 is to correct the reaction of the linear actuator 8.

With these two feedbacks, position control of the two-stage servo by the tracking actuator 6 and the linear actuator 8 is performed.

Next, in the case of speed control for accessing the optical spot 33 to a target track on the optical disc 1, the output of the track pulse count circuit 13 is controlled by the speed detection circuit 15 and the controller 29 to control the speed via the SW 31. The signal is input to the command circuit 16. Here, the speed detection circuit 15 detects the moving speed of the light spot 33 by calculating the period at which the light spot 33 crosses the track. Further, the speed command circuit 16 receives the moving direction from the controller 29, and according to the contents of the track counter inside the track pulse count circuit 13, which indicates the number of tracks to the target at each moment,
A speed command for the light spot 33 is output.

The speed detection circuit 15 and speed command circuit 16
The output is amplified by the error amplification circuit 17, and the phase correction circuit 1 controls the speed of the tracking actuator 6.
Similarly to the position control described above, the output of the objective lens phase correction circuit 24 is input to the drive amplifier 26 via the SW 32 under the control of the controller 29, in order to correct the reaction of the linear actuator 8. The adder 20 connects the output of the drive amplifier 26 and the phase correction circuit 1.
The output of 8 is added. The output of the adder 20 is input to a drive amplifier 21, the output of the drive amplifier 21 is fed back to the tracking actuator 6 to drive and control the tracking actuator 6, and the output of the drive amplifier 26 is fed back to the linear actuator 8 to drive and control the tracking actuator 6. The actuator 8 is driven and controlled.

[0019] As a result, two-stage servo speed control is performed by the tracking actuator 6 and linear actuator 8, which cause the objective lens system 3 to follow, in the same way as the position control that causes the objective lens system 3 to follow the track.

Furthermore, a runaway detection circuit 28 detects that the tracking actuator 6 has run out of control based on the objective lens position detection signal that is the output of the objective lens position detection circuit 7, and a runaway detection circuit 28 detects that the tracking actuator 6 has run out of control based on the output of the drive amplifier 26. A runaway detection circuit 27 is provided to detect runaway.

Based on the signals from the runaway detection circuits 27 and 28, the controller 29 generates a damping signal, which is a drive signal at a level that causes the linear actuator 8 to generate maximum acceleration in the deceleration direction, in order to control the runaway. The generation circuit 25 is controlled. The output of this damping signal generation circuit 25 is input to the drive amplifier 26 via the SW 32 under the control of the controller 29.
Runaway can be controlled by causing the linear actuator 8 to generate maximum acceleration in the deceleration direction.

The controller 29 also inputs the objective lens position detection signal to the linear actuator follow-up circuit 19, and in order to correct the reaction of the linear actuator 8, the adder 20 outputs the output of the drive amplifier 26 and the linear actuator follow-up circuit 19. By adding the output and feeding it back to the tracking actuator 6 via the drive amplifier 21, it is possible to control the relative displacement of the tracking actuator 6 with respect to the linear actuator 8 to zero.

Furthermore, when the speed of the linear actuator 8 reaches a speed at which it can be drawn into linear actuator speed control, which will be described later, due to the output of the damping signal generation circuit 25, the outputs of the speed detection circuit 15 and the speed command circuit 16 become erroneous. The signal is amplified by the amplifier circuit 17 and input to the phase correction circuit 18 which controls the speed of the tracking actuator 6, and is also input to the phase correction circuit 23 which controls the speed of the linear actuator 8.

In the linear actuator speed control, the output of the phase correction circuit 23 is input to the drive amplifier 26 via the SW 32 under the control of the controller 29, and the output of the drive amplifier 26 is fed back to the linear actuator 8. Refers to drive control. Here, the speed command circuit 16 receives the moving direction from the controller 29 or the direction detection circuit, and
It is designed to output a speed command value that performs speed damping to a speed that can be pulled into the speed control of the stage servo.

The runaway detection circuit 27, as shown in FIG.
The drive amplifier 26 includes a current detection resistor 35 that converts the drive current flowing through the linear actuator 8 into a current voltage according to the input drive signal, and a differential amplifier 36 that inputs the voltage converted by the current detection resistor. The output of this differential amplifier 36 is then output by comparators 37 and 38.
When the positive and negative confidence signal levels exceed the reference values E and -E, the output of the NAND gate 39 becomes high level,
The output of the NAND gate 39 is output to the controller 29 as a runaway detection signal.

The timing of these signals is shown in FIG. That is, as shown in FIG. 3(A), the level of the drive signal increases rapidly, and as a result, the output of the differential amplifier 36 increases as shown in FIG. 3(B), and as shown in FIG. 3(C).
As shown in FIG. 3, the output of the comparator 37 becomes low level when it exceeds the reference value E of the comparator 37, and
As shown in (D), the output of the NAND gate 39 becomes high level, making it possible to detect runaway.

The runaway detection circuit 28, as shown in FIG.
The objective lens position detection signal output from the objective lens position detection circuit 7 is detected by comparators 40 and 41 on the positive side,
If the negative confidence level exceeds the reference value E, -E,
The output of the NAND gate 42 becomes high level, and the NAND
The output of the D gate 39 is output to the controller 29 as a runaway detection signal.

The timing of these signals is shown in FIG. That is, as shown in FIG. 5(A), when the objective lens system 3 shifts and exceeds a predetermined movement amount, the level of the objective lens position detection signal increases rapidly, and as shown in FIG. 5(B), the level of the objective lens position detection signal increases. When the reference value E of is exceeded, the output of the comparator 40 becomes low level, and the output of the NAND gate 42 becomes high level as shown in FIG. 3(C), so that runaway can be detected.

The operation of the optical information recording/reproducing apparatus constructed as described above will be explained.

First, when the optical spot 33 is located within a predetermined number of tracks from the innermost or outermost track of the optical disc 1, for example, if the optical spot 33 goes out of control due to a disturbance such as an impact being applied in the tracking direction. The operation will be explained using FIG.

Here, the predetermined number of tracks is the number of tracks required to reach a speed that can be pulled into the position control of the two-stage servo by linear actuator speed control and two-stage servo speed control. In addition, as for the method of determining whether the position is within or above the predetermined number of tracks at the time of runaway, first, if runaway occurs when controlling the position of the light spot 33, it is determined based on the track address that was being followed immediately before the runaway. If runaway occurs during speed control, the track address immediately before the runaway is detected is sent to the controller 2 by the output of the track pulse count circuit 13.
9 is recognized and the position at the time of runaway is detected and judged.

When runaway is detected by the runaway detection circuit 27 or 28, regardless of whether the control state before the runaway is position control for following the track or speed control for accessing the target track, the controller 29 causes the SW 30 to act as a linear actuator. The tracking circuit 19 is switched to zero the relative displacement of the tracking actuator 6 with respect to the linear actuator 8, and the maximum allowable speed V0 of the optical head 4, which has been accelerated due to disturbance etc. to the speed during the seek operation, becomes a speed controllable speed V1. The damping signal generation circuit 25 generates a damping signal for a predetermined time t0 so that the linear actuator 8 is maximally accelerated in the deceleration direction and braked (period A in FIG. 6). Next, the moving direction is inputted from the controller 29, and the linear actuator speed is controlled, and speed damping is performed until time t1 when the speed becomes controllable for the two-stage servo (period B in FIG. 6). Furthermore, 2
The speed control of the stage servo is controlled to a speed at which the position of the second stage servo can be controlled (period C in FIG. 6). In this way, the position control of the two-stage servo can be carried out quickly and reliably.

Next, an explanation will be given of the operation in the case where the optical spot 33 goes out of control when it is located more than the predetermined number of tracks from the innermost or outermost track of the optical disc 1.

When runaway is detected by the runaway detection circuit 27 or 28, the controller 29 switches SW30 to the linear actuator tracking circuit 19 to zero the relative displacement of the tracking actuator 6 with respect to the linear actuator 8, and switches SW31 to direction detection. circuit 1
1, and further switches SW32 to phase correction circuit 23.

That is, the operation in this case is such that when the aforementioned optical spot 33 is located within a predetermined number of tracks from the innermost or outermost track of the optical disc 1, the damping signal generating circuit 25 The only difference is that a damping signal is not generated and speed damping is not performed, and the direction of movement is input by the direction detection circuit 11 instead of the controller 29 to control the linear actuator speed, but the other operations are the same.

When the position control of the light spot 33 is out of control, the off-track detection circuit 12 detects the out-of-position control, and if the light spot 33 is located on more than the predetermined number of tracks, With the control in the event of a runaway, it is possible to pull into position control again. This off-track detection circuit 12 can be realized, for example, by the configuration shown in FIG. 3 described above, and can detect that the position control is deviated from the tracking error signal.

As described above, according to the present embodiment, even if the optical spot 33 goes out of control when it is located near the innermost or outermost track of the optical disc 1, the linear actuator 8 can perform optical information recording and reproduction. Speed damping can be performed quickly without colliding with the device main body 22,
Control can be restored in a short time.

Furthermore, since the relative displacement between the objective lens system 3 and the linear actuator 8 is controlled to be zero, the objective lens system 3 does not swing and the tracking signal and total reflected light amount signal can be accurately output even in the event of runaway. can be detected.

[0039]

As explained above, according to the present invention, the optical information recording/reproducing apparatus of the present invention has an optical system that forms a light spot on a track provided on an information recording medium,
An optical head for recording, reproducing, or erasing information on the information recording medium using the light spot; an optical head driving means for driving the optical head in a cross-track direction; and an optical head driving means for driving the optical head in a direction across the track, and causing the tip of the optical head to follow the center of the track. tracking control means; speed detection means for detecting the relative speed of the optical spot with respect to the track based on a tracking error signal from the tracking control means; and position detection means for detecting the relative position of the optical system with respect to the optical head driving means. a runaway detection means for detecting a runaway state when the optical head runs out of control; a position control means for controlling the light spot to follow a predetermined track; and a position control means for controlling the light spot to follow a predetermined track when the optical head runs out of control; In an optical recording and reproducing device having a speed control means for controlling the speed,
comprising a damping means for decelerating the optical head at a maximum acceleration by the runaway detection means, and after the damping means decelerates the optical head at the maximum acceleration to a speed controllable speed of the optical head; The speed control means sets the speed of the optical head to a speed that allows position control, and the position control means controls the position, so even if the optical head runs out of control, the optical head will not collide with the main body of the optical information recording/reproducing device. This can be prevented, and the predetermined control of focus servo, tracking servo, etc. can be quickly and reliably restored.

[Brief explanation of drawings]

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

FIG. 2 is a configuration diagram showing the configuration of a runaway detection circuit that detects runaway of a tracking actuator according to an embodiment.

FIG. 3 is a timing diagram illustrating the operation of the runaway detection circuit shown in FIG. 2 according to one embodiment.

FIG. 4 is a configuration diagram showing the configuration of a runaway detection circuit that detects runaway of a linear actuator according to an embodiment.

FIG. 5 is a timing diagram illustrating the operation of the runaway detection circuit shown in FIG. 4 according to one embodiment.

FIG. 6 is an explanatory diagram illustrating how the speed of an optical head is controlled according to one embodiment.

[Explanation of symbols]

1...Optical disc 3...Objective lens system 6...Tracking actuator 8...Linear actuator 15...Speed detection circuit 16...Speed command circuit 25...damping signal generation circuit 27...Runaway detection circuit 28...Runaway detection circuit 29...Controller

Claims (3)

[Claims] 1. An optical head having an optical system that forms a light spot on a track provided on an information recording medium, and recording, reproducing, or erasing information on the information recording medium using the light spot, and the optical head. an optical head driving means for driving the optical head in the cross-track direction; a tracking control means for causing the tip of the optical head to follow the center of the track; and a tracking error signal from the tracking control means to detect the relative speed of the optical spot with respect to the track. a speed detecting means for detecting the relative position of the optical system with respect to the optical head driving means; a runaway detecting means for detecting a runaway state when the optical head runs out of control; In an optical recording and reproducing apparatus, the optical recording and reproducing apparatus includes a position control means for controlling the optical head to follow a predetermined track, and a speed control means for controlling the speed of the optical spot based on the output of the speed detection means, An optical recording/reproducing device characterized by being equipped with damping means for decelerating at maximum acceleration. 2. If the optical head runs out of control while the optical spot is formed at a position within a predetermined number of tracks from the innermost or outermost track, the runaway detection means detects the optical head. 2. The optical recording and reproducing apparatus according to claim 1, further comprising damping means for decelerating at maximum acceleration. 3. Total reflected light amount detection means for detecting a signal indicating the total amount of reflected light generated when passing the track, and a signal from the total reflected light amount detection means and a tracking error signal from the tracking control means. a moving direction detecting means for detecting a direction, and when the optical head runs out of control when the optical spot is formed at a position a predetermined number of tracks or more from the innermost circumference or outermost circumference of the track, Control is performed so that the relative displacement of the optical system with respect to the optical head driving means is zero, and the speed of the optical head driving means is controlled by the speed control based on the moving direction detecting means, and when a predetermined speed is reached. 2. The optical recording and reproducing apparatus according to claim 1, further comprising two-stage control means that switches over and controls said position control means.