JPH05114146A - Optical recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent erroneous counting to surely seek a target track by counting the number of generated pulses of a track error signal/reproduced signal in accordance with the absence/presence of bits on the track traversed by an optical head. CONSTITUTION:The track error signal generated for seek and a reproduced signal RF are inputted to comparators 31 and 32 and are binarized. The threshold V (refl) of the comparator 31 is set to 0 or about 0, and the threshold ref2 of the comparator 32 is set to such value that the presence or the absence of bits recorded on tracks can be detected. Since signals TE and RF are different by phases, the output of the comparator 31 is inverted by an inverter 33 and is used and through a selector 34 and is counted by a counter 35. The counter 35 counts the number of tracks traversed by the optical head by the number of edges of input pulses. A selector 34 selects the comparator 31 in the case of the absence of bits on the traversed track but selects the comparator 32 in the case of the presence of bits. By this constitution, erroneous counting of the track signal dependent upon bits of the track is prevented to perform quick access.

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 device such as an optical disc drive device, a magneto-optical disc drive device, a compact disc drive device, etc.
The present invention relates to an optical recording / reproducing apparatus capable of reducing the address seek error and preventing high-speed access by preventing erroneous counting of a track error signal due to track pits when counting the number of jump tracks during a seek operation.

[0002]

2. Description of the Related Art An optical recording / reproducing apparatus, that is, an information recording medium having tracks formed in a spiral shape or a concentric shape, an optical head for recording / reproducing information, and the optical head on the information recording medium. A function of moving information to an arbitrary target track and a means of detecting the number of tracks moved by a track error signal detected by the optical head, recording information on an information recording medium, and optically reproducing the information. An optical recording / reproducing apparatus such as an optical disk drive or a magneto-optical disk drive equipped with is conventionally known.

In this optical recording / reproducing apparatus, when a reproduction signal is read from an information recording medium such as an optical disk or a magneto-optical disk, the track engraved on the information recording medium at the seek operation when the optical head is moved to the target track. The number of zero-cross points of the track error signal generated when crossing is detected and the number of these zero-cross points is counted.

In this case, in the conventional counting method, the track signal is disturbed by the pits (holes) recorded in the preformatted portion or the data portion of the disc, the zero cross point cannot be detected, or even at a place different from the original place. The track signal has a zero cross point. As a result, there is an inconvenience that the number of moving tracks becomes an incorrect count, and the optical head seeks to a track different from the target track.

As one method for solving such inconvenience, a binary output of a signal obtained by integrating the speed signal of the head and a track cross signal are AND-processed and input to a one-shot pulse forming circuit to make a true signal. An apparatus that extracts only the track signal of the above has been proposed (Japanese Patent Laid-Open No. HEI-2)
-273384). However, even with this method, it is not always possible to accurately count the number of tracks.

FIG. 6 is a functional block diagram showing an example of the essential structure of a seek servo system in a conventional optical disk device. In the figure, 1 is a bang-bang control pulse generation circuit, 2 is an optical pickup, 3 is a tracking error detection circuit, 4 is a phase compensation circuit, 5 is a waveform shaping circuit, 6 is a speed detector, 7 is a calculator, and 8 is an optical circuit. Pickup position detector, 9 is an amplifier, 10 is a phase compensation circuit, 11 is a waveform shaping circuit, 12 is a speed detector, 13 is a calculator, 14
Is a D / A converter, 15 is an amplifier, 16 is a phase compensation circuit,
17 is a microcomputer, 18 is a switch unit, 1
8a is a step jump mode switch, 18b is a tracking mode switch, 18c is a track jump mode switch, 18d is a carriage hold mode switch, 18e is a coarse seek mode switch, and 18f is a home position hold mode switch. 1
9 is a power amplifier, 20 is a tracking actuator, 2
1 is a power amplifier, 22 is a coarse motor, and S1
Is a track count pulse output, S2 is a speed signal, S
3 is an encoder output, S4 is a speed signal, S5 is a home position output, S6 is an optical pickup position pulse output, S7 is speed data, and S8 is a mode switching signal.

In the conventional optical disk device shown in FIG. 6, the microcomputer 17 controls the seek servo system. During seek operation, mode switching signal S
8 is output to operate the switch unit 18. For example, in the coarse seek mode, the coarse seek mode switch 1
8e is turned on to drive the coarse movement motor 22, and
In the step jump mode, the step jump mode switch 18a is turned on to drive the tracking actuator 20. The same applies to the track jump mode and tracking mode.

The tracking error is detected by the tracking error detection circuit 3 connected to the optical pickup 2. That is, the reflected light from the optical disk is received by the light receiving element for detecting the track error provided in the optical pickup 2, and the detection signal is given to the tracking error detection circuit 3.

The output of the tracking error detection circuit 3 is transmitted to the microcomputer 17 as a track count pulse output S1 via the waveform shaping circuit 5 and counted to select a desired track position. Next, a conventional counting operation during seek will be described.

FIG. 7 is a timing chart for explaining the counting operation at the seek time in the conventional optical disk device. In the figure, A) is a track, B) is a track error signal, and C) is a track count pulse.
Is a track and the corresponding track count pulse, and 'and' indicate an erroneous pulse.

In FIG. 7, if a pit due to a defect exists in the track shown in A), a track error signal shown in B) is generated. For example, if a track has a pit, a track error signal is generated twice, and as shown in C), two track count pulses and ' Is generated. Similarly, two track count pulses, 'are generated in the track. Therefore, in the case of FIG. 7, although the number of tracks is actually six, eight tracks are counted. In this way, if the track error signal is disturbed by the influence of the pits, an erroneous count occurs and it is impossible to reliably seek to the target track.

By the way, in the current optical disk device, a high-speed access function is demanded as one of high performance. During this seek operation, if the wrong number of tracks is counted due to the influence of optical disk preformatting, etc., the light beam will not move at the originally required moving speed, and it will be desired when the optical head stops. There is a problem that the track cannot be sought.

For example, when the track error signal is disturbed by the influence of pre-formatting or the like, the track count pulse is not generated at the position where it should originally exist, which causes malfunction, which hinders high-speed access. There was an inconvenience.

[0014]

SUMMARY OF THE INVENTION In the present invention, such inconveniences in the conventional optical disk device, namely,
Solves the inconvenience that high-speed access cannot be performed because the stop position of the optical head cannot seek to the desired track if the track count pulse is erroneously counted due to the influence of optical disk preformatting, etc., when searching for the track position. However, by preventing the influence of pits (holes) on the tracks that cause erroneous counts, reducing the occurrence of erroneous counts and reducing address seek errors, an optical disk device that enables high-speed access is provided. The purpose is to provide.

[0015]

According to the present invention, firstly,
An information recording medium having a spiral or concentric track, an optical head for recording and reproducing information, a moving means for moving the optical head to an arbitrary target track on the information recording medium, and the optical head. And a means for detecting the number of tracks moved by the track error signal detected by the information recording medium,
In an optical recording / reproducing apparatus such as an optical disk drive or a magneto-optical disk drive having a function of optically reproducing, a first pulse error signal is binarized to generate an active signal of one pulse. A comparator, a second comparator that binarizes one reproduction signal to generate an active signal of one pulse, and a selector that selects one of the active signals output from the first and second comparators , A moving track number counter for counting the pulse active signals output from the first and second comparators selected by the selector, and the pulse active signals from the second comparator during the seek operation. When it is output, it activates the pulse output from the first comparator by the selector. The strobe signal, and configured to retrieve the target track position is corrected by the pulse active signal outputted from the second comparator input to the moving track counter.

Secondly, in the first optical recording / reproducing apparatus described above, the moving track number counter has a function of operating at both edges of the active signal of the input pulse, and the seek operation is performed by the second comparator. When the pulse active signal is output, instead of the pulse active signal output from the first comparator by the selector, the pulse active signal output from the second comparator is input to the moving track number counter. Then, the target track position is searched for.

Thirdly, in the first or second optical recording / reproducing apparatus, the selector for selecting the output of the first and second comparators is an OR gate circuit, and the output of the OR gate circuit is the number of moving tracks. It is configured to input to the counter.

[0018]

In the present invention, attention is paid to the point that the reproduction signal is generated corresponding to the pit position of the track. When the active signal of the reproduction signal is detected during the seek operation, the reproduction signal is reproduced instead of the track error signal. The signal is used or the correction is performed by the OR processing. That is, when there is no pit in the track traversed by the optical head (optical pickup), the track error signal is counted as in the conventional case, and when there is a pit, the reproduction signal is counted instead of the track error signal. As a result, the occurrence of erroneous counting due to the influence of the pits is prevented (the invention of claim 1).

Further, the track error signal and the reproduced signal are OR-processed and corrected to prevent erroneous counting (the invention of claim 3). Further, when there is no pit, the track error signal is counted, and when there is a pit, the reproduction signal is used instead of the track error signal, or OR is performed with the reproduction signal. By generating two pulses with respect to the track error signal of (1), it is possible to count with the detection resolution of 1/2 track, and it is possible to perform seek control with higher accuracy and higher speed. And the invention of claim 3).

[0020]

Embodiment 1 Next, an optical recording / reproducing apparatus of the present invention will be described in detail with reference to the drawings. This embodiment corresponds to the inventions of claims 1 and 3.

FIG. 1 is a functional block diagram showing an embodiment of the main configuration of the optical recording / reproducing apparatus of the present invention. In the figure, 31 is a first comparator, 32
Is a second comparator, 33 is an inverter, 34 is a selector, 35 is a track number counter, U1 is an OR gate circuit, TE is a track error signal, RF is a reproduction signal, and V (ref1) is a first threshold. (Threshold) voltage, V (r
ef2) indicates the second threshold voltage.

As shown in FIG. 1, in the optical recording / reproducing apparatus of the present invention, two comparators are used, and the track error signal TE and the reproduction signal RF generated during the seek operation are respectively compared. It is input to the means, that is, the first comparator 31 and the second comparator 32, and is converted into a binarized signal. The first threshold voltage V (ref1) is applied to one of the first comparators 31 as a reference voltage. This threshold voltage V (r
ef1) is set to 0 V (volt) or a value in the vicinity thereof.

On the other hand, the second threshold voltage V (ref2) is applied to the second comparator 32 as a reference voltage. This threshold voltage V (ref2) is set to such a value that the presence or absence of pits recorded on the track can be detected. Since the track error signal TE and the reproduction signal RF have different phases, one of the outputs of the first comparator 31, for example, is used by being inverted by the inverter 33.

Then, these two comparators 31,
In order to select only one of the outputs of 32, a selector 34 is provided and its output is input to the track number counter 35. The track number counter 35 indicates the number of rising (or falling) edges of the input pulse and
Count the number of tracks that the optical head has crossed.

When there is no pit on the track traversed by the optical head, the selector 34 operates the first comparator 3
The output of 1 is selected, and when there is a pit, the output of the second comparator 32 is selected. Next, this Figure 1
With respect to the optical recording / reproducing apparatus shown in, the counting operation at the time of seek will be described.

FIG. 2 is a timing chart for explaining the counting operation at the time of seek in the optical recording / reproducing apparatus of the present invention shown in FIG. In the figure, A) is a track, B) is a track error signal, C) is an inverted pulse of the output pulse of the first comparator 31, D) is a reproduction signal,
E) is the output pulse of the second comparator 32, F) is the output of the selector 34, and G) is the track count pulse. Other symbols are the same as those in FIG. 7, and
Is a track and a track count pulse corresponding to the track, and 'and' are erroneous pulses, and "and" are output pulses of the second comparator 32.

FIG. 2 corresponds to FIG. 7 for explaining the conventional example, and here also shows a case where pits are present in the track as well. Therefore, the actual number of tracks is six. As shown in A) of FIG. 2, if a pit exists in the track, the track error signal is disturbed, and the output (inversion pulse) of the first comparator 31 is as shown in C) of FIG. become.

That is, since extra track count pulses ',' are generated in the binarized pulse, the actual number of tracks is 6, if this is left as it is,
8 pulses are counted in total. In this invention,
It is noted that the reproduction signal RF shown in D) of FIG. 2 is generated corresponding to the pit position of the track. In this case, instead of the track error signal, the second reproduction signal RF shown in E) of FIG. The output pulse "," of the comparator 32 is supplied to the selector 3
4 is selected and input to the track number counter 35.

Therefore, the track number counter 35 is
As shown in FIG. 2G), a pitless track,
, And the reproduction signal RF of the track in which the pit exists are input, and 6 which is the same as the actual number of tracks is counted. As a result, when counting the number of tracks during seek operation,
The influence of the pit that causes the erroneous count is eliminated, and the optical head can accurately seek to the target track (the invention of claim 1).

Next, the selector 34 will be described. As a select circuit for selecting the outputs of the first and second comparators 31 and 32, a commonly used known circuit can be used. In FIG. 1, the OR gate circuit U1 is used, and as shown in C) of FIG. 2, the active signal of the inverted pulse of the output pulse of the first comparator 31 and the output pulse of the second comparator 32 are used. Inputting the active signal of 1), both active signals are OR-processed, and an input signal of the track number counter as shown in G) of FIG. 2 is obtained.

As described above, if the OR gate circuit U1 is used as the selector 34, it is possible to realize a select circuit having a simple structure without the generation of the select control signal (the invention of claim 3). Here, regarding the selector 34,
Another embodiment will be described.

FIG. 3 is a functional block diagram showing the detailed structure of the selector used in the optical recording / reproducing apparatus of the present invention. (1) and (2) are diagrams showing different embodiments. is there. Reference numerals in the drawing are the same as those in FIG. 1, and 36 is a select control signal generator, U1 to U.
3 and U7 are gate circuits, U4 and U6 are gated inverters, and U5 is an inverter.

FIGS. 3A and 3B show the case where a general selector is used. The select control signal generator 36 is generated by the active signal of the output pulse of the second comparator 32 to open the gates of the AND gate circuits U2 and U3 or the gates of the gated inverters U4 and U6 to generate the first control signal. And a count pulse corresponding to the outputs of the second comparators 31 and 32 is output.

In the above-described embodiment, the track number counter 35 is incremented or decremented by 1 each time one track is moved. Therefore, the track number counter 35 may operate at the rising (or falling) edge of the output pulses of the first and second comparators 31 and 32, as shown in G) of FIG.

However, in the seek operation, a drive system is also adopted in which the optical head is accelerated up to a half track before the target track and decelerated before the half track, thereby performing a high speed seek. Therefore, an example suitable for such a driving method will be described below as a second example.

[0036]

Second Embodiment Next, another embodiment of the optical recording / reproducing apparatus of the present invention will be described. This embodiment is claimed in claim 2.
And corresponds to the invention of claim 3.

FIG. 4 is a functional block diagram showing another embodiment of the main structure of the optical recording / reproducing apparatus of the present invention. The reference numerals in the figure are the same as those in FIG. 1, and
Reference numeral 37 indicates a track number counter.

As already mentioned, in the previous embodiment, 1
In this case, the track number counter 35 operates at one edge (for example, rising edge) of one track error signal to count one track error signal. On the other hand, in this embodiment, the track number counter 37 operates on both edges for one track error signal, and
It differs in that it counts individual pieces.

Therefore, in the second embodiment shown in FIG. 4, it is possible to count with the detection resolution of 1/2 track, the seek operation accuracy is improved, and the speed is increased. Other configurations and operations are the same as in the case of FIG. Next, a time chart is shown.

FIG. 5 is a timing chart for explaining the counting operation at the time of seek in the optical recording / reproducing apparatus of the present invention shown in FIG. Reference numerals in the figure are the same as those in FIG.

This FIG. 5 corresponds to the above-mentioned FIG. 2, and in the track where the pit exists, the false pulse ','
The fact that is mixed in is the same as in the case of FIG. In this embodiment, the track number counter 37 operates on both edges for one track error signal, as shown in FIG.
2), the detection resolution is only 1/2 track.

Therefore, the reason why the erroneous counting is prevented is the same as in the previous embodiment. Although the output pulse of the first comparator 31 shown in FIG. 5C has 15 edges, The number counter 37 counts 11 as shown in G) of FIG. In this way, if the track number counter 37 is operated at both edges, even in the seek control system in which a brake pulse is applied to the optical head from the moment when the optical head reaches a half track before the target track, the influence of the existence of pits is not affected. There is no risk that the number of tracks will be erroneously counted due to the removal, and the application position, timing, etc. of the brake pulse can be reliably detected.

[0043]

According to the present invention, the number of moving tracks during the seek operation is counted by the pulse generated from the track error signal when there is no pit in the track traversed by the optical head. When there is, it is configured to count with the generated pulse from the reproduction signal RF instead of the track error signal. Therefore, even if the track error signal is disturbed by the influence of the pits, erroneous counting does not occur and it is possible to surely seek to the target track.

According to the second aspect of the present invention, the count of the number of moving tracks during the seek operation is determined so that when there is no pit on the track traversed by the optical head, a 1/2 track detection resolution is generated by a pulse generated from the track error signal. Is counted, and when there is a pit, it is configured to count up by 2 or count down by 2 by a pulse generated from the reproduction signal RF instead of the track error signal. Therefore, even in the seek control method that counts the number of moving tracks with a resolution of 1/2 track, it is possible to prevent the occurrence of erroneous counting, and to reliably control the application position and timing of the brake pulse. it can.

According to the third aspect of the present invention, the select circuit for selecting whether to use the pulse generated from the track error signal or the pulse generated from the reproduction signal RF as the signal for counting the number of moving tracks during the seek operation. Is composed of an OR gate circuit. Therefore, with a circuit having a simple configuration, it is possible to similarly prevent the occurrence of false counts.

[Brief description of drawings]

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

FIG. 2 is a timing chart for explaining a counting operation at the time of seek in the optical recording / reproducing apparatus of the present invention shown in FIG.

FIG. 3 is a functional block diagram showing a detailed configuration of a selector used in the optical recording / reproducing apparatus of the present invention.

FIG. 4 is a functional block diagram showing another embodiment of the main configuration of the optical recording / reproducing apparatus of the present invention.

5 is a timing chart for explaining a counting operation at the time of seek in the optical recording / reproducing apparatus of the present invention shown in FIG.

FIG. 6 is a functional block diagram showing an example of a main part configuration of a seek servo system in a conventional optical disc device.

FIG. 7 is a timing chart for explaining a counting operation at the time of seek in the conventional optical disc device.

[Explanation of symbols]

 31 First Comparator 32 Second Comparator 33 Inverter 34 Selector 35 Track Number Counter

Claims (3)

[Claims] 1. An information recording medium having a spiral or concentric track, an optical head for recording and reproducing information, and a movement for moving the optical head to an arbitrary target track on the information recording medium. Means and a means for detecting the number of tracks moved by a track error signal detected by the optical head, an optical disk drive or a magneto-optical disk having a function of recording information on an information recording medium and optically reproducing it. In an optical recording / reproducing apparatus such as a disk drive, a first comparator for binarizing the one track error signal to generate an active signal of one pulse, and one binarizing the reproducing signal for one A second comparator for generating an active signal of a number of pulses, and one of the active signals output from the first and second comparators And a moving track number counter that counts the active signals of the pulses output from the first and second comparators selected by the selector, and during the seek operation, the second comparator outputs When the pulse active signal is output, the pulse active signal output from the first comparator by the selector is corrected by the pulse active signal output from the second comparator to correct the number of moving tracks. An optical recording / reproducing apparatus characterized by inputting to a counter and searching for a target track position. 2. The optical recording / reproducing apparatus according to claim 1, wherein the moving track number counter has a function of operating at both edges of an active signal of the input pulse, and the pulse number is read from the second comparator during seek operation. When the active signal is output, the first signal is output by the selector.
Instead of the pulse active signal output from the second comparator, the pulse active signal output from the second comparator is input to the moving track number counter to search the target track position. Recording / playback device. 3. The optical recording / reproducing apparatus according to claim 1, wherein the selector that selects the output of the first and second comparators is an OR gate circuit, and the output of the OR gate circuit is a moving track number counter. An optical recording / reproducing apparatus characterized by inputting to the.