JPS63206977A - Optical recording and reproducing device - Google Patents

Abstract

PURPOSE:To stably position a shift mechanism of an optical head by providing plural phase compensating circuits having different phase compensation characteristics and switching these circuits with each other according to the shift distance of the shift mechanism. CONSTITUTION:The phase compensating circuits 81-8N having different compensation characteristics are provided together with a changeover switch 9 which selects one of those circuits 81-8N, and a control circuit 10 which delivers a target position to a target position signal output circuit 7 to turn on and off a switch and to switch the switch 9. Then a phase compensating circuit having the optimum phase compensation characteristics is selected in response to the shift distance of a shift mechanism 5 of an optical head 1 even though the output voltage of a drive circuit for the mechanism 5 is saturated. Thus the mechanism 5 can be positioned at high speed and with high stability.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a plurality of phase compensation circuits having different phase compensation characteristics for performing phase compensation of a difference signal between a target position signal and a current position signal of an optical head. The present invention relates to an optical recording/reproducing device equipped with the following.

2. Description of the Related Art In recent years, access speeds of optical heads of optical recording and reproducing devices have been dramatically increased.

A conventional optical recording/reproducing device will be explained below. Fig. 7 is a block diagram showing the configuration of a conventional optical recording/reproducing device, Fig. 8 is a drive voltage waveform diagram when the transport mechanism of the optical head is moved, and Fig. 9 is a diagram showing the drive voltage waveform when the transport mechanism of the optical head is moved. It is a position signal waveform diagram at the time.

In FIG. 7, 1 is an optical head of an optical recording/reproducing device, 2 is an objective lens drive device that drives the objective lens of the optical head 1, 3 is a first drive circuit that drives the objective lens drive device, and 4 is a first drive circuit that drives the objective lens drive device. 1 a switch for switching on or off the input of the output of the drive circuit 3 to the objective lens drive device 2; 6 a transport mechanism for transporting the optical head 1;
7 is a current position detection circuit that generates a current position signal corresponding to the current position of the transfer mechanism 6; 7 is a target position signal output circuit that outputs the target position of the transfer mechanism 5; 8 is a current position signal output from the current position detection circuit 6; A phase compensation circuit 12 compensates for the phase of the difference signal between the position signal and the target position signal output from the target position signal output circuit, and outputs the entire target position to the target position signal output circuit γ. A control circuit 11 for switching between on and off operations is a second drive circuit that controls the transfer machine j:IJ5'c to follow the target position based on the output signal of the phase compensation circuit 8. In Figure 8, E
is the drive voltage waveform when unsaturated, and F is the drive voltage waveform when partially saturated. In FIG. 9, G is the current position signal waveform which is the output signal of the current position detection circuit 6 of FIG. 8, and H is the target position signal waveform which is the output signal of the target position signal output circuit 7.

The operation of the conventional optical recording device configured as described above will be described below.

First, the switch 4 is turned off in response to the output signal of the control circuit 12, the tracking control by the objective lens driving device 2 is turned off, and the new target position of the transfer mechanism 5 is output to the target position signal output circuit.

Next, the difference signal between the current position signal of the transfer mechanism 6 detected by the current position detection circuit 6 and the target position signal corresponding to the new target position output from the target position signal output circuit γ is input to the full phase compensation circuit 8. and performs phase compensation. Next, the output signal of the phase compensation circuit 8 is inputted to the second drive circuit 11, and the transfer mechanism 5 is driven by the output signal of the second drive circuit 11.
Control is performed so that the current position signal and the target position signal match.

The control circuit 12 determines the time required for the transfer mechanism 6 to move from the difference between the target position immediately before switching the target position to the new target position and the new target position, that is, the moving distance of the transfer mechanism 5. At this time, since the power supply voltage of the second drive circuit 11 is finite, as the moving distance increases, the drive voltage waveform of the moving mechanism 6, which is the output signal of the second drive circuit 11, as shown in FIG. Some of them are saturated. Therefore, if the moving distance is long, the phase compensation characteristics of the phase compensation circuit 8 will not be optimal, and it will take time for the transfer mechanism 5 to stabilize at the target position, as shown in FIG. 9. Therefore, the control circuit 12 turns on the switch 4 after the time period until the transfer mechanism 5 becomes stable, and the first
The objective lens drive device 2 was driven by the output signal of the drive circuit 3, and the tracking control was turned on.

Problems to be Solved by the Invention However, in the conventional configuration, since the power supply voltage of the drive circuit of the transfer mechanism is finite, part of the output signal of the drive circuit saturates as the moving distance increases. This has the problem that the characteristics are not optimal and that it takes time to stably position the transfer mechanism.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and has as its entire object to provide an optical recording/reproducing device that can stably position a transfer mechanism regardless of the distance traveled.

Means for Solving the Problems To achieve this object, the optical recording/reproducing device of the present invention has a plurality of phase compensation circuits having different phase compensation characteristics, and adjusts the phase compensation according to the moving distance of the transport mechanism. It has a configuration in which the circuit is switched.

Effect: With this configuration, the transfer mechanism can be stably positioned regardless of the transfer distance.

EXAMPLE An example of the present invention will be described below with reference to all the drawings.

FIG. 1 is a block diagram of the structure of an optical recording/reproducing apparatus according to a first embodiment of the present invention, and FIG. 2 is a diagram of a loop transfer characteristic of a transfer mechanism control system. In Figure 1, 81.82...
...8N is the Nth number, each having different phase compensation characteristics.
9 is a changeover switch that selects all of the phase compensation circuits 81 and 82.8N, and 10 is a changeover switch that outputs the target position to the target position signal output circuit 7, and controls the on/off operation of switch 4 and the changeover switch. This is a control circuit that performs switching of 9. Note that 1 is an optical head, 2 is an objective lens drive device, 3 is a first drive circuit, 4 is a switch, 5 is an ID transfer mechanism, 6 is a current position detection circuit, and γ is a target position signal output circuit, which are conventional examples. The configuration is the same as that of . Second
In the figure, M and C are gain characteristic curves of the loop transfer characteristic of the control system composed of the phase compensation circuits 81 to 8N, the second drive circuit 11, the transfer mechanism 6, and the current position detection circuit 6, and B
and D is the phase characteristic curve of the loop transfer characteristic of the control system Q. The operation of the optical recording/reproducing apparatus of this embodiment configured as described above will be explained below. First, the switch 4 is turned off by the output signal of the control circuit 10, and the tracking control by the objective lens driving device 2 is turned off.

At this time, it is assumed that the switch 9 has, for example, the first phase compensation circuit 81, which has optimal phase compensation characteristics when the tracking control is on, and is in the gold on state. Next, control circuit 1
Outputs the new target position from 0 to the target position signal output circuit,
Furthermore, a control signal is outputted from the control circuit 10 so that the changeover switch 9 selects, for example, the second phase compensation circuit 82 having phase compensation characteristics optimal for the moving distance of the transfer mechanism 6. Next, the difference signal between the current position signal of the transfer mechanism 5 detected by the current position detection circuit 6 and the target position signal corresponding to the new target position output from the target position signal output circuit is input to the full phase compensation circuit 82. and performs phase compensation. Next, the output signal waveform 2 of the phase compensation circuit 82 is input to the drive circuit 11, and the output signal of the second drive circuit 11 causes the transfer mechanism 5
is controlled so that the current position signal and the target position signal match.

The control circuit 1o calculates the amount of time required for the transfer mechanism 6 to move from the difference between the target position immediately before switching the target position to the new target position and the new target position, that is, the moving distance of the transfer mechanism 6, and After the time has elapsed, the changeover switch 9 is switched so that the phase compensation circuit 81 is turned on,
According to the present embodiment, as described above, all operations are performed, including turning on the switch 4, driving the objective lens driving device 2 using the output signal of the first drive circuit, and turning on the tracking control. As shown in Figure 2, the gain characteristic curve when the output voltage of the second drive circuit is not saturated is the gain characteristic curve B when the output voltage is partially saturated.
By selecting all the phase compensation circuits having the optimum phase characteristic so that the phase characteristic curve B becomes the phase characteristic curve when Can be done.

Other embodiments of the present invention will be described below with reference to all the drawings.

FIG. 3 is a block diagram showing the configuration of an optical recording/reproducing device in another embodiment of the present invention, FIG. 4 is a position signal waveform diagram when the transport mechanism is moving, and FIG. 6 is a position signal waveform diagram of FIG. 4. a of
FIG. In FIG. 3, 13 is a constant voltage circuit that generates all minute voltages, and 14 is a target position signal output circuit 7.
16 is a first comparator that compares the output signal of the subtracter 14 with the output signal of the target position signal output circuit T; 15; is an adder that outputs a signal obtained by adding the output signal of the constant voltage circuit 13 to the output signal of the target position signal output circuit γ;
18 is an output signal of the adder 16 and a target position signal output circuit T
A third comparator 18 is a second comparator that compares the output signals of the target position signal output circuit 7 and the current position signal detection circuit 6. Note that 1 is an optical head, 2f'i objective lens drive device, 3 is a first drive circuit,
4 is a switch, 6 is a transfer mechanism, 6 is a current position detection circuit,
7 is a target position signal output circuit, and 1o is a control circuit, which have the same configuration as the first embodiment. Figures 4 and 6
In the figure, 0 is the current position signal which is the output signal of the current position detector e when the transfer mechanism 6 moves, H is the target position signal which is the output signal of the target position signal output circuit 7, and F is the output signal of the adder 15. The output signal waveform, J, is the output signal waveform of the subtracter 14.

The operation of the optical recording/reproducing main apparatus of another embodiment configured as described above will be explained below. First, the control circuit 10
The switch 4 is turned off by the output signal, and the tracking control by the objective lens driving device 2 is completely turned off. At this time, it is assumed that the switch 9 turns on, for example, the first phase compensation circuit 81, which has an optimal phase compensation characteristic when the tracking control is on. Next, the new target position is output from the control circuit 1o to the target position signal output circuit 7, and the changeover switch 9 is connected to a second phase compensation circuit 82, for example, which has phase compensation characteristics optimal for the moving distance of the transfer mechanism 5. A control signal is output from the control circuit 1o so as to select.

Next, a difference signal between the current position signal of the transfer mechanism 6 detected by the current position detection circuit 6 and the target position signal corresponding to the new target position output from the target position signal output circuit 7 is input to the phase compensation circuit 82. and performs phase compensation. Next, the output signal of the phase compensation circuit 82 is input to the drive circuit 11 of the second driver 2, and the transfer mechanism 6 is driven by the output signal of the second drive circuit 11, so that the current position signal and the target position signal match. Control as follows.

Next, the subtracter 14 subtracts the output signal of the constant voltage circuit 13 from the output signal of the target position output signal output circuit 7, and the comparator 1
6, the control circuit 1o determines that the transfer mechanism 6 has reached the position corresponding to the output signal J of the subtracter 14 by comparing it with the output signal of the current position detection circuit 6. Next, the control circuit 1o
From the time when the above-mentioned arrival is determined, the comparator 18 compares the output signal of the target position output circuit γ and the output signal of the current position detection circuit 6, and determines that the transfer mechanism 6 has reached the target position. Until time T. Measure.

Then, by the control circuit 10, at said time. is the time T during which tracking can be controlled sufficiently stably. If the changeover switch 9 is longer than the phase compensation circuit 81, the control circuit 10
is turned on, and the switch 4 is turned on. That is, the objective lens driving device 2 is driven by the output signal of the first driving circuit 3, and the tracking control is turned on. Time τ,. is T. If it is shorter, the control circuit 10 adds the output signal of the constant voltage circuit 13 to the output signal of the target position output signal output circuit 7 by the adder 16 from the time when the target position is reached, and the comparator °1 The output signal of the adder 15 is completely compared with the output signal of the target position signal output circuit 7, and it is determined that the transfer mechanism 6 reaches the position corresponding to the output signal of the adder 16.
Measure 2o'c. Next, if the time 20 is longer than the time T, the control circuit 10 changes the changeover switch 9 so that the phase compensation circuit 81 is turned on.
In other words, the first drive circuit 3 is turned on to drive the objective lens drive device 2 and the tracking control is turned on. Time T20 is T. If it is shorter, calculate the time Tn to reach the position corresponding to the output signals of the adder 16, the subtracter 14, and the target position signal output circuit 7 in the same manner as above, and switch when it becomes longer than To. The switch 9 is switched so that the phase compensation circuit 81 is turned on, and the process is repeated until the tracking control is turned on.

As described above, according to this embodiment, the time T for the optical head transfer mechanism 5 to transfer between a target position and a position a minute distance ΔX from the target position is measured, and the time T is used to stably control tracking. Time T. By determining that the distance is greater than , the optical head can be positioned more quickly and stably regardless of the moving distance.

The switching of the phase compensation circuit to the tracking control ON state is determined by the speed signal obtained by differentiating the current position signal by the speed detection circuit 19 as shown in the block diagram shown in FIG. You may do so.

In this case, the optical head can be positioned quickly and stably with a simpler configuration.

Effects of the Invention The present invention uses a plurality of gold-plated phase compensation circuits having different phase compensation characteristics, and even when the output voltage of the drive circuit of the optical head transport mechanism is saturated, it can be optimized according to the moving distance of the optical head transport mechanism. By selecting a phase compensation circuit having a phase compensation characteristic, it is possible to realize an excellent optical recording and reproducing apparatus that can stably and quickly position the optical head transport mechanism.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration 2 of an optical recording/reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a round transfer characteristic diagram of a transfer mechanism control system, and FIGS. A block diagram of the optical recording/reproducing apparatus in the embodiment, FIG. 4 is a position signal waveform diagram when the transport mechanism of the optical head moves, FIG. 5 is an enlarged view of part a in FIG. 4, and FIG. 7 is a diagram of the conventional optical head. FIG. 8 is a drive voltage waveform diagram when the optical head transport mechanism moves, and FIG. 9 is a position signal waveform diagram when the optical head transport mechanism moves. DESCRIPTION OF SYMBOLS 1... Optical head, 2... Objective lens drive device, 3... First drive circuit, 4...
...Switch, 5...Transfer machine, 6...
Current position detection circuit, A... Target position signal output circuit, 9... Changeover switch, 1o...
Control circuit, 11... Second drive circuit, 81...
...First phase compensation circuit, 82...Second phase compensation circuit, 8N...Nth phase compensation circuit. Name of agent: Patent attorney Toshio Nakao and one other person. 4--Sweet ÷ 3 To-Rabbit 1's panic box prevention circuit 32--1 2nd phase compensation circuit Fig. 2 Fig. 4 Fig. distance time-opening Fig. 5 distance exposure review 4--one person e-) + 31-11 Is it possible to reproduce the crime of car 1? -Ichika 2's Shunbako ML Tribute to the Bird N's Seagull Ellipse ■9 each--4 sides 4 moxa switch Fig. 6 Fig. 7

Claims (1)

[Claims] an optical head that has a function of recording and reproducing data on and from an information recording medium and is composed of a semiconductor laser, an objective lens, a photodetector, etc., and has an objective lens driving device; and a first optical head that drives the objective lens driving device. a drive circuit, a first switch that switches the output of the first drive circuit on or off, a transfer mechanism that transfers the optical head, and outputs a current position signal corresponding to the current position of the transfer mechanism. a current position detection circuit; a current position signal output circuit that outputs a target position signal of the transfer mechanism; and a plurality of circuits that perform phase compensation of a difference signal between the current position signal and the target position signal and have different phase compensation characteristics. a second switch for switching between the plurality of phase compensation circuits, and a second drive circuit for controlling the transfer mechanism to follow the target position according to the output signal of the phase compensation circuit, An optical recording/reproducing device characterized in that a phase compensation circuit is switched according to a moving distance of the transport mechanism.