JP2946436B2 - Optical disk drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device,
More particularly, the present invention relates to an optical disk device that performs preformat masking of a sector mark or the like at the time of detecting a track pulse, does not have a track miss count, and enables a stable track jump.

[0002]

2. Description of the Related Art Conventionally, in a track jump control method in an optical disk apparatus having a feed motor for driving an optical head and a tracking actuator for driving a condenser lens in the optical head, a light beam is moved from a current track to a target track. When jumping to the light beam
Uses a tracking error signal when moving on a disk .

In this method, first, a tracking pulse is obtained by passing a tracking error signal through a comparator. And this signal, indexes the track jump number from the current track position to the target track position, the jump pulse and the brake pulse is applied to the actuator to the target track position, performs a track jump.

[0004]

However, the scratches on the disk, the noise of the preformat signal, and the like cause noise, the track pulse is disturbed, the track pulse detection is not performed well, and the timing for turning on the tracking is shifted, and the like. Jumps may fail. As a result, there is a problem that an accurate position is not obtained, and the access time is extended.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an optical disk device which operates stably by masking a preformat superimposed on a track pulse at the time of a track jump.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to an optical disk apparatus having a feed motor for driving an optical head and a tracking actuator in the optical head for driving a condenser lens. detects the preformat signal of the optical disc by the playback signal obtained from the optical head, the read pre-format signal, it is apparent spatial position of the preformat signal is slightly larger than the pre-format signal width remember that spatial position at the time of reproduction A means for outputting a PF signal, wherein the means is configured to output the PF signal at the previously remembered spatial position even when tracking is lost and a reproduction signal cannot be obtained; When jumping from the current track to the target track, the track that occurs when the light beam crosses the track Generating a track pulse from the signal based on King errors, remove the preformat signal with a PF signal from the track pulse preformat signal is superimposed, comprising: means for obtaining a PF track pulses,
A means for determining the position of the light beam using a PF track pulse; a means for applying a control signal to the tracking actuator to cause the light beam to track jump; when the light beam moves to the center between target tracks ,
A deceleration pulse is output, and the deceleration time and acceleration time become the same.
A means for switching to position control at the point of time .

[0007]

[Function] By configuring the optical disk device as described above,
When a track jump from the current track to the target track is performed, since a preformat mask such as a sector mark is performed when a track pulse is detected, there is no track miss count, and stable track entry is possible.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will now be described with reference to FIGS.
Explanation will be made based on FIG. FIG. 1 is a block diagram showing a configuration example of an optical disc device according to the present invention. As shown in the figure, the microprocessor 10 (hereinafter referred to as “MP
U ") is a single-chip microprocessor having an input port, an output port, a memory, a counter and the like inside. The internal circuit operates at 10 MHz, and operates at a speed that does not cause any problem as a control system.

Reference numeral 50 denotes an optical disk, which is rotated at a constant rotation speed by a spindle motor 30. Reference numeral 34 denotes a feed motor for driving the optical head 31.
A tracking actuator 32 is provided in the optical head 31.
, And controls the position of the light beam 36 normally. Reference numeral 33 denotes a midpoint sensor that detects a midpoint displacement of the tracking actuator 32 with respect to the optical head 31. The optical head 31 outputs a tracking error signal SA, a reflected light sum signal SB, and a reproduction signal SD as a data signal.

Reference numeral 11 denotes a D / A converter, the output of which is connected to a tracking actuator 32 via a switch SW1 and to an adder 13, where the output of the D / A converter is added to the output of the midpoint sensor 33. Motor 3
4 can be driven.

Reference numeral 40 denotes an ENDEC (encoder decoder)
In this method, a preformat signal of the optical disk is detected based on a reproduction signal obtained from the optical head, and further, recording data is separated, and mediation of data exchange between a higher-level computer not described and the optical disk is performed.
At this time, the ENDEC used here is, for example, WD60C
31 (manufactured by Western Digital Corp.), which reads a preformat signal at the time of reproduction and outputs a PF signal which memorizes the position and knows the position of the preformat signal. Then, even if tracking is lost during subsequent access and a reproduced signal cannot be obtained, P
The F signal is configured to be output at the previously remembered position.

Reference numeral 16 denotes a track error filter for removing a DC component of the tracking error signal, and its output is connected to a comparator 15 for shaping the waveform and obtaining a track pulse. Reference numeral 17 denotes a pre-format mask circuit for removing a pre-format signal included in a track pulse by using the PF signal. Hereinafter, this output is referred to as a PF track pulse. The pre-format mask circuit 17 can control whether or not to mask with the MPU 10. When not masking, the track pulse TP is output as it is.

Reference numeral 20 denotes a sum signal filter for removing the DC component of the reflected light sum signal SB. The output of the sum signal filter is connected to a comparator 19 for shaping the waveform and obtaining a sum signal pulse. The PF track pulse is connected to a counter / input port of the MPU 10. The period of the PF track pulse is measured by the period counter 14 using a clock of 10 MHz, and is taken into the MPU 10.

PF track pulse signal and sum signal pulse S
P is connected to the direction detector 18 and outputs the direction of the light spot with respect to the track in binary logic. This direction detecting method is described in detail in Japanese Patent Publication No. 1-50972. This direction signal is connected to the input port of the MPU 10. The MPU 10 has a configuration that can be controlled by software.

FIG. 2 is a timing chart for explaining the removal of the preformat signal contained in the track pulse TP using the PF signal. The preformat signal is removed from the track pulse TP with the ENDEC PF signal to obtain a PF track pulse.

FIG. 3 is an explanatory diagram of preformat removal and track jump, and shows respective waveforms of a tracking error signal SA, a track pulse TP, a PF track pulse, and a jump pulse. FIG. 4 shows an example of a preformat mask circuit.

In the optical disk apparatus configured as described above, the disk 50 normally rotates at a constant rotation speed, focus servo is applied, and position control called tracking servo is performed. When a track jump command is received from a host device (not shown), the tracking servo switch SW1 is set to the D / A converter 11 side.

From this time, the MPU 10 sends an acceleration pulse in the direction in which the tracking actuator 32 should be moved to D / A.
Output from converter 11. At the same time, the preformat mask circuit 17 is operated. The number of PF track pulses is counted by a counter inside the MPU 10, and when the light beam has just moved to the center between tracks to be moved, a deceleration pulse is output in the opposite direction. When the deceleration time becomes equal to the acceleration time, the tracking is turned on. That is, the acceleration time and the deceleration time are the same. At this time, the peak values of the acceleration pulse and the deceleration pulse may be the same.

At this time, the method of counting the number of tracks is important, and will be described with reference to FIG. The method is bang-bang control by counting the number. FIG. 3 is an explanatory diagram for a case where two tracks are jumped, for example.

If the pulse edge of the track pulse signal TP obtained from the tracking error signal SA is counted, a two-track jump can be performed . For example,
If the number of jumps is two, an acceleration pulse is applied until the second rising edge of the pulse, and a deceleration pulse is applied for the same duration as the acceleration time. This is processed by a counter inside the MPU 10.

The width of the preformat is about 60 μsec.
Track pulse width at track jump is about 500μse
Since it is c, the preformat width is about 12% compared to the track pulse width. Therefore, the PF track pulse width can be regarded as the track pulse width.

Since the PF track pulse is generated from the track pulse to prevent a track count error, the tracking on timing can be accurately performed with respect to the track position, so that the track can be stably entered. Become.

[0023]

As described above, according to the present invention, when a track jump from the current track to the target track is performed using a track pulse, a preformat mask such as a sector mark is performed when a track pulse is detected. Therefore, there is no track miscount, a stable track rush is possible, and an excellent effect that a stable track jump can be obtained.

[Brief description of the drawings]

FIG. 1 is an example of a block diagram showing a configuration of an optical disk device to which a track jump control method of the present invention is applied.

FIG. 2 is a timing chart for explaining that a preformat signal included in a track pulse TP is removed using a PF signal.

FIG. 3 is an explanatory diagram of preformat removal and track jump.

FIG. 4 is a diagram illustrating a configuration example of a preformat removal circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Microprocessor 11 D / A converter 12 Servo circuit 13 Adder 14 Period counter 15 Comparator 16 Track error filter 17 Preformat mask circuit 18 Direction detector 19 Comparator 20 Sum signal filter 30 Spindle motor 31 Optical head 32 Tracking actuator 33 Middle point Sensor 34 Feed motor 35 Condenser lens 36 Light beam 40 ENDEC 50 Optical disk

Claims (1)

(57) [Claims] 1. An optical disk device having a feed motor for driving an optical head and a tracking actuator for driving a condenser lens in the optical head, wherein a preformat signal of the optical disk is obtained by a reproduction signal obtained from the optical head. detects said during reproduction reads the preformat signals, comprising means for outputting a PF signal reveals the spatial position of the preformat signal with slightly larger than the pre-format signal width remember its spatial position, said means out tracking, said even in a state in which the reproduction signal can not be obtained, the PF signal, elaborate remember before the sky
Configured as output between positions, when jumping light beam from a current track to a target track, the light beam generates a track pulse from the signal based on the tracking error that occurs when crossing a track, the Means for removing the preformat signal from the track pulse on which the preformat signal is superimposed using the PF signal to obtain a PF track pulse; and means for obtaining the position of the light beam using the PF track pulse. Means for applying a control signal to the tracking actuator to cause the light beam to track jump, and when the light beam moves to the center between target tracks , decelerates in the opposite direction.
Output, and when the deceleration time and acceleration time become the same
Characterized by having means for switching to position control with
Optical disk device .