JPH10312539A - Optical information reproducing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical information reproducing apparatus which can increase a probability that a track whose reproduction is defective can be reproduced by a retrying operation. SOLUTION: Reproduced signals of information recorded on respective tracks are read out simultaneously in one scanning operation by photodetectors 101, 102, 103 which are installed so as to correspond to a plurality of tracks, and the reproduced signals are binarized and reproduced by binarization circuits A 107, 108 and a binarization circuit B 109 whose systems are different. Then, when a reproduction defect exists in a track corresponding to the photodetector 101 out of the reproduced signals by the photodetectors 101, 102, 103, the photodetector 103 is moved by an objective-lens drive means 112 up to the track in which the reproduction defect is generated, and the track is reproduced again by using the binarization means B 109 whose system is different.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an optical information reproducing apparatus for reproducing information recorded on an optical information recording medium such as an optical card.

[0002]

2. Description of the Related Art Recently, optical information recording media (optical cards,
2. Description of the Related Art An optical information recording apparatus that enables information to be recorded by condensing and irradiating a light beam onto an optical disc or the like and reproducing the recorded information has been widely used.

An optical information recording apparatus (optical card recording / reproducing apparatus) using an optical card as a recording medium includes an optical card having a plurality of tracks parallel to each other.
The information recording / reproducing is performed while moving the optical head for recording / reproducing information to / from the optical card relatively in the track direction of the optical card. In the case of recording and reproducing information while moving, there is a problem that the information reproducing speed cannot be increased.

Therefore, a so-called multi-track read method has been considered in which a plurality of tracks are read at once during reproduction to increase the reproduction speed. By the way, as a recording method when data is recorded on an optical information recording medium, (1) a mark position recording method in which recording pits are provided in one-to-one correspondence with "1" of encoded data to be recorded on the medium. .

(2) A mark length recording method in which recording pits are provided so that recording pits start or end at "1" of encoded data to be recorded on a medium. There is. In the mark length recording method, when binarizing a reproduction signal, how to accurately detect a mark edge poses a problem, and such a reproduction signal edge detection method is a typical one. There are a slice level detection method in which signals are binarized by comparing signals with appropriate values, and a differentiation method in which peak points are detected after passing through a differentiating circuit.

FIG. 6 shows an example of a slice level detection method for detecting an edge of a reproduction signal based on a slice level. In this slice level detection method, FIG.
The reproduction signal shown in (a) is given, and when the reproduction signal exceeds a predetermined slice level a, the output is set to "1". When the reproduction signal is equal to or lower than the slice level a, the output is set to "0". The binarized signal shown in b) is generated.

However, in the slice level detection method,
If the recording medium surface has dirt, dust, scratches, etc., the level and amplitude of the reproduction signal fluctuate in a complicated manner. Edge detection cannot be performed. for that reason,
Taking advantage of the characteristic that the duty ratio of the reproduction signal is 50%, binarization is performed by controlling the slice level a. However, when the level of the reproduction signal fluctuates rapidly as shown in FIG. 6C, the binarization may be performed by controlling the slice level a so as to follow the fluctuation at this time. In some cases, binarization cannot be performed accurately as shown in FIG.

On the other hand, FIG. 7 shows an example of a differentiation method for detecting the edge of a reproduced signal and detecting the peak of a differentiated waveform.
In this differentiation method, the reproduction signal shown in FIG. 7A is differentiated to generate a differentiated signal shown in FIG. 7B. The edge of the reproduced signal is detected by detecting the peak point of the differential signal. In the case of the differential method, unlike the slice level method, it is hardly affected by the level fluctuation of the reproduction signal, but has a disadvantage that high-frequency noise is emphasized by the differential operation. In the case where the above-mentioned multi-track read method is adopted, one of these binarization methods of the reproduced signal is used in a unified manner.

[0009]

However, these 2
As described above, the binarization method includes a possibility that a binarized signal cannot be generated accurately due to some disadvantages. To take measures to compensate for these disadvantages,
The circuit scale becomes large, causing problems in terms of mounting area and cost.

This is a more serious problem in the case where the multi-track read method is adopted, since there are a plurality of binarization circuits for performing parallel processing. In addition, if there is a track which has a reproduction failure due to a defect such as dirt or scratch on the surface of the recording medium or a defect at the time of recording, the reproduction of the track becomes impossible even if retried by the same binarization method. There was also a problem.

[0011] The present invention has been made in view of the above circumstances,
An object of the present invention is to provide an optical information reproducing apparatus capable of increasing the probability that a defective track can be reproduced by retrying by utilizing the multi-track read.

[0012]

According to the first aspect of the present invention,
A plurality of reproduction units are provided corresponding to a plurality of tracks of the information recording medium, and read out the reproduction signals of the information recorded on these tracks simultaneously by a single scan, and digitize and reproduce the read reproduction signals. An optical information reproducing apparatus having signal processing means, wherein the binarization means of at least one of the plurality of reproduction signal processing means is different from the binarization means of the other reproduction signal processing means. The reproduction is performed again by using a binarization unit of a different system in place of the binarization unit of the reproduction signal processing unit corresponding to the track in which the reproduction signal read out by the one-time scanning has become a reproduction failure. I have to.

According to a second aspect of the present invention, a plurality of tracks of an information recording medium are provided corresponding to a plurality of tracks, and readout signals of information recorded on these tracks are simultaneously read out by a single scan. In an optical information reproducing apparatus having a plurality of reproduction signal processing means for binarizing a signal and reproducing the same, at least one of the plurality of reproduction signal processing circuits is provided with a plurality of reproduction signal processing means.
Re-playback is performed by using a binarizing means of a different system in place of the binarizing means of the reproduction signal processing means corresponding to the track in which the reproduction signal read out by the one-time scanning has a reproduction failure. To do.

According to a third aspect of the present invention, there is provided the first or second aspect.
In the above description, the plurality of reproduction signal processing units each include a light receiving element for reading a reproduction signal of information recorded on a corresponding track, and by moving these light receiving elements in a direction orthogonal to the track, a reproduction failure is generated. The switching of the reproduction signal processing means corresponding to the changed track to the binarization means of a different system is performed.

As a result, according to the first aspect of the present invention,
A retry can be performed on a track in which a reproduction signal read out by one scanning operation has become a reproduction failure by using a binarizing means of a different method, and the probability that reproduction becomes possible can be increased.

According to the second aspect of the present invention, during normal reproduction (when reproduction failure does not occur), reproduction can be performed for all reproduction signal processing means using the same type of binarization means. it can. According to the third aspect of the present invention, by moving the light receiving element in a direction perpendicular to the track,
It is possible to switch between different types of binarization means.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 shows a schematic configuration of a reproduction signal processing circuit capable of multi-track reading in an optical information reproducing apparatus to which the present invention is applied. In other words, the reproduction signal processing circuit in this case can reproduce information recorded on three tracks on the optical card at the same time. The presence or absence of a track pit is detected by a change in the amount of light, and a reproduced signal is output.

In the figure, reference numeral 10 denotes an optical head, on which light receiving elements 101, 102 and 103 corresponding to three tracks are mounted. The outputs of the light receiving elements 101, 102, and 103 are input to I / V conversion circuits 104, 105, and 106, respectively, where they are amplified and subjected to current / voltage conversion. Further, the I / V conversion circuits 104, 10
The outputs of 5 and 106 are binarized circuits A 107 and 1
08 is input to the binarization circuit B109, and binarization is performed.

In this case, the binarizing circuits A 107 and 108
Means that the duty ratio of the reproduced signal is 5 as the edge detection method.
Slice level detection system (8-10 modulation system) for performing binarization by controlling the slice level utilizing the characteristic of 0%
The binarization circuit B109 employs a differential method of detecting a peak of a differential waveform of a reproduction signal and performing binarization as an edge detection method.

The binarizing circuits A107, A107,
8, the output of the binarization circuit B109 is input to the demodulation circuit 110 and demodulated, and further, the demodulated data is input to the controller 111 and subjected to error correction processing.
As a result, data of three tracks corresponding to the light receiving elements 101, 102, and 103 are reproduced.

On the other hand, an objective lens driving means 112 is connected to the controller 111. The objective lens driving means 112 is for driving an objective lens (not shown) of the optical head 10 in a direction orthogonal to the track according to an instruction from the controller 111.
Or, when a reproduction failure occurs in the track corresponding to 102, the light receiving element 103 is moved together with the objective lens to the track in which the reproduction failure has occurred. The element 101 or 102 is moved to the track where the reproduction failure has occurred.

Next, the operation of the embodiment configured as described above will be described. Now, the optical card is moved in the track direction and the light receiving elements 101, 102, 103 on the optical head 10 are moved.
When three tracks are moved with respect to the light-receiving element 10, a change in the amount of light according to the presence or absence of pits in these tracks is caused.
Light is received at 1, 102, and 103. The outputs of the light receiving elements 101, 102 and 103 are respectively I / V
The signals are input to conversion circuits 104, 105, and 106, where they are amplified and current / voltage converted. The outputs of the I / V conversion circuits 104, 105, and 106 are input to the binarization circuits A 107 and 108 and the binarization circuit B 109, respectively, as reproduced signals, where the binarization is performed. In this case, the binarization circuits A 107 and 108 perform binarization by controlling the slice level taking advantage of the characteristic that the duty ratio of the reproduction signal is 50%, and the binarization circuit B 109 differentiates the reproduction signal. Binarization is performed by detecting the peak of the waveform.

The binarizing circuits A107, A107,
The output binarized by the octal and binarization circuit B109 is demodulated by a demodulation circuit 110, and the demodulated data is input to a controller 111, where an error correction process is performed, and the light receiving elements 101, 102, The data is reproduced as data of three tracks corresponding to 103.

Here, it is assumed that a reproduction failure has occurred in one of the three tracks tried to be reproduced. The track where the reproduction failure has occurred is the light receiving element 101.
Is the corresponding track, the objective lens driving means 112 is controlled by the controller 111 to
Is driven in the direction orthogonal to the track, and the light receiving element 103 is moved to the track where the reproduction failure has occurred. Then, again, the light amount change according to the presence or absence of the pit of this track is received by the light receiving element 103, and this output is
Binarization circuit B109 having a different system from binarization circuit A107
, A retry reproduction process is performed.

On the other hand, assuming that the track where the reproduction failure has occurred is the track to which the light receiving element 103 corresponds, the objective lens driving means 112 drives the objective lens of the optical head 10 in a direction orthogonal to the track by the instruction of the controller 111. The light receiving element 101 or 102 is moved to the track where the reproduction failure has occurred, and the light receiving element 101 or 102 receives a light amount change in accordance with the presence or absence of a pit on the track. By performing binarization using a different binarization circuit A107 or A108, a retry reproduction process is performed.

Therefore, in this way, if a defective track occurs in a multi-track read for simultaneously reproducing the recorded information of a plurality of tracks, the system is replaced by a binarizing circuit corresponding to this track. Two different
Since it is possible to perform reproduction again using the value conversion circuit,
The retry at this time can increase the probability of being able to be reproduced.

In the embodiment described above, the number of tracks that can be reproduced simultaneously is three, but may be more or less. Although a typical slice level detection method and a differential method are used as the edge detection method of the binarization circuit, other methods of the binarization circuit, for example, A / D conversion of a reproduced signal and digital conversion are performed. A method of binarizing, a method of binarizing by detecting a peak or bottom of a reproduced signal, a method of binarizing by adjusting the amplitude of a reproduced signal or a differential signal by an AGC (automatic gain control) circuit, or the like. May be used. Further, binarization circuits A107 and A108
Uses the same type of binarization circuit, but may use a different type.

(Second Embodiment) In the second embodiment, a different type of binarizing circuit is used only at the time of retry, and the same 2 binarization circuit is usually used for all tracks for simultaneous reproduction.
It uses the valuation method. Here, the number of tracks for simultaneous reproduction is set to three.

In FIG. 2, reference numeral 20 denotes an optical head, on which light receiving elements 201, 202 and 203 corresponding to three tracks are mounted. The outputs of these light receiving elements 201, 202 and 203 are respectively I / V
The signals are input to conversion circuits 204, 205, and 206, and amplification and current / voltage conversion are performed. The outputs of the I / V conversion circuits 204 and 205 are respectively output to the binarization circuit A20.
7 and 208 to be binarized. The output of the I / V conversion circuit 206 is input to a binarization circuit A 209 and a binarization circuit B 210 to be binarized.

In this case, the binarizing circuits A 207, 208,
209 adopts a slice level detection method for performing binarization by controlling a slice level by utilizing the characteristic that the duty ratio of a reproduced signal is 50% as an edge detection method, and the binarization circuit B210 uses an edge detection method as an edge detection method. A differential method is employed in which the peak of the differential waveform of the reproduced signal is detected and binarized.

The outputs of the binarization circuits A 207 and A 208 are input to a demodulation circuit 212 for demodulation.
The output of the binarization circuit A 209 and the output of the binarization circuit B 210 are input to the selector 211, and one output selected by the selector 211 is input to the demodulation circuit 210 to perform demodulation.

In this case, during normal reproduction, the selector 211 outputs a selection signal 214 from the controller 213.
To select the binarized signal output from the binarizing circuit A209, and in the reproduction by retry, the controller 21
The binarization signal output from the binarization circuit B210 is selected by the selection signal 214 from the third circuit instead of the binarization circuit A209.

The data demodulated by the demodulation circuit 210 is input to the controller 213, where error correction processing is performed, and as a result, the light receiving elements 201, 202, 20
The data of three tracks corresponding to No. 3 is reproduced.

On the other hand, an objective lens driving means 215 is connected to the controller 213. The objective lens driving means 215 drives an objective lens (not shown) of the optical head 20 in a direction orthogonal to the track according to an instruction from the controller 213.
Alternatively, when a reproduction failure occurs in a track corresponding to 202, the light receiving element 203 is moved together with the objective lens to the track where the reproduction failure has occurred. In this case, the selector 211 selects the binarized signal output from the binarization circuit B210 by the reproduction by the retry.
When a reproduction failure occurs in the track corresponding to the light receiving element 203, the objective lens driving unit 215 does not drive the objective lens, and the selector 211 selects the binarized signal output from the binarization circuit B210. .

In such a configuration, it is assumed that a reproduction failure occurs in one of the three tracks tried to be reproduced through the light receiving elements 201, 202, and 203. Now, assuming that the track having a reproduction failure is the track corresponding to the light receiving element 201, the controller 21
In response to the instruction of 3, the objective lens driving means 215 drives the objective lens of the optical head 20 in a direction perpendicular to the track, and moves the light receiving element 203 to the track where the reproduction failure has occurred. At the same time, the controller 213
The selector 211 is set to select the binarized signal output from the binarization circuit B210 by the selection signal 214 of.

From this state, a change in the amount of light according to the presence or absence of a pit of the track in which the reproduction failure has occurred is detected by the light receiving element 2.
03, the output from the light receiving element 203 is
Instead of the binarizing circuit A207, the binarizing circuit B210 previously selected by the selector 211 binarizes the signal, and demodulates the binarized signal to perform a retry reproduction process.

On the other hand, if the track on which the reproduction failure has occurred is a track corresponding to the light receiving element 203, the objective lens driving means 215 does not drive the objective lens, and the selector 211 replaces the binarization circuit A209 with the binarization circuit A209. The binarized signal output from B210 is selected, and a retry reproduction process is performed by demodulating the binarized signal.

Therefore, even in this case, if a defective track occurs in the multi-track read, a different-type binarization circuit is used again instead of the binarization circuit corresponding to this track. Can be reproduced, so that the probability of being reproducible by retrying at this time can be increased.

In the case of normal reproduction (when reproduction failure does not occur), reproduction can be performed for all three tracks for which reproduction has been attempted by the binarization circuit of the same system. Variations can be eliminated.

Further, when the track where the reproduction failure occurs is the track to which the light receiving element 203 corresponds, the retry operation can be performed without moving the other light receiving elements 201, 201.

In the above-described embodiment, the number of simultaneous reproductions is three, but may be more or less.
In addition, a typical slice level detection method and a differential method are used as the edge detection method of the binarization circuit, but other methods of the binarization circuit, for example, A / D conversion of a reproduced signal and digital conversion into two. A method of binarizing, a method of binarizing by detecting a peak or bottom of a reproduced signal, a method of binarizing by adjusting the amplitude of a reproduced signal or a differential signal by an AGC (automatic gain control) circuit, or the like. May be used. Further, the binarization circuits switched by the selector 211 are two types, that is, the binarization circuit A209 and the binarization circuit B210, but may be three or more types. Furthermore, although only one binarization circuit corresponding to one light receiving element has a plurality of configurations, a binarization circuit corresponding to each of the plurality of light receiving elements may have a similar configuration.

(Third Embodiment) In the third embodiment, the operation of moving the optical head at the time of retry is not required. Here, the number of tracks for simultaneous reproduction is also three.

In FIG. 3, reference numeral 30 denotes an optical head on which light receiving elements 301, 302 and 303 corresponding to three tracks are mounted. The outputs of these light receiving elements 301, 302 and 303 are I / V
The signals are input to conversion circuits 304, 305, and 306, and are amplified and subjected to current / voltage conversion. The output of the I / V conversion circuit 304 is output to a binarization circuit A307 and a binarization circuit B308.
, And is binarized. The output of the I / V conversion circuit 305 is input to the binarization circuit A 309 and the binarization circuit B 310, where the output is binarized.
Are output from a binarization circuit A311 and a binarization circuit B31.
It is input to 2 and binarized.

In this case, the binarization circuits A307, A309,
Numeral 311 adopts a slice level detection method for performing binarization by controlling a slice level by making use of the characteristic that the duty ratio of a reproduced signal is 50% as an edge detection method, and the binarization circuits B308, 310, 312 As an edge detection method, a differential method of detecting a peak of a differential waveform of a reproduction signal and performing binarization is adopted.

The outputs of the binarization circuit A 307 and the binarization circuit B 308 are input to a selector 313, and one output selected by the selector 313 is input to a demodulation circuit 316 for demodulation. Also, a binarization circuit A
309 and the output of the binarization circuit B310
14 and one output selected by the selector 314 is input to a demodulation circuit 316 and demodulated.
Further, a binarization circuit A311 and a binarization circuit B312
Is input to the selector 315, and the selector 315
Is input to the demodulation circuit 316 and demodulation is performed.

In this case, the selectors 313, 314, 31
5 is a controller 3 for normal reproduction.
17 by the selection signals 318, 319 and 320 from
When the binarization signals output from the binarization circuits A 307, 309, and 311 are selected and the reproduction is performed by retry, the selection signals 318, 319, and 320 from the controller 317 are used instead of the binarization circuits A 307, 309, and 311. 2
The binarization signals output from the binarization circuits B308, 310, and 312 are selected.

The data demodulated by the demodulation circuit 316 is input to the controller 317, where an error correction process is performed, and as a result, data of three tracks corresponding to the light receiving elements 301, 302, and 303 are reproduced.

Thus, in such a configuration, it is assumed that a reproduction failure occurs in one of the three tracks tried to be reproduced through the light receiving elements 301, 302, and 303. Now, assuming that the track in which the reproduction failure has occurred is the track corresponding to the light receiving element 301, the selector 313 outputs
A binarized signal output from the binarizing circuit B 308 is selected in place of the binarizing circuit A 307, and a retry reproduction process is performed by demodulating the binarized signal.

Also, in the case where the track where the reproduction failure has occurred is the track corresponding to the light receiving element 302 or 303, the selection signals 319 and 32 are retried in the same manner as described above.
0, the selector 314 or 315 causes the binarization circuit B
A retry reproduction process is performed by selecting the binarized signal output from 310 and 312 and demodulating this signal.

Accordingly, in this way, if a defective track occurs in a multi-track read for simultaneously reproducing the recorded information of a plurality of tracks, the system is replaced with a binarizing circuit corresponding to this track. Two different
Since it is possible to perform reproduction again using the value conversion circuit,
The retry at this time can increase the probability of being able to be reproduced.

Further, in such a multi-track read, a retry operation can be performed when a defective track occurs without moving the light receiving elements 301, 302 and 303, so that the reproduction operation can be quickly performed again. The transition can be made and the overall playback speed can be increased.

Further, in the case of normal reproduction (when reproduction failure does not occur), reproduction can be performed for all three tracks for which reproduction has been attempted by the binarization circuit of the same system. Variations can be eliminated.

In the above-described embodiment, the number of simultaneous reproductions is three, but may be more or less.
In addition, a typical slice level detection method and a differential method are used as the edge detection method of the binarization circuit, but other methods of the binarization circuit, for example, A / D conversion of a reproduced signal and digital conversion into two. A method of binarizing, a method of binarizing by detecting a peak or bottom of a reproduced signal, a method of binarizing by adjusting the amplitude of a reproduced signal or a differential signal by an AGC (automatic gain control) circuit, or the like. May be used. Also,
Although a typical slice level detection method and a differential method are used for the edge detection method of the binarization circuit, other binarization circuit methods, for example, A / D conversion of a reproduced signal and digital binarization. A method of performing binarization by detecting a peak or a bottom of a reproduced signal, a method of performing amplitude adjustment of a reproduced signal or a differential signal by an AGC (automatic gain control) circuit, and performing binarization. You may. Further, the binarization circuits which can be switched by the selectors 313, 314, 315 are binarization circuits A307, 309, 311 and a binarization circuit B
308, 310, and 312 are used, but three or more types may be used.

On the other hand, as shown in FIG.
Circuits corresponding to the binarization circuits B308, 310, and 312 are all binarized circuits of different systems, and binarization circuits B32
The binarization circuit C322 and the binarization circuit D323 may be used. Other circuits are the same as those in FIG. In such a case, an operation of moving the optical head at the time of retry may be required.
3, since the retry can be performed, the probability of being reproducible at the time of the retry is further increased.

(Fourth Embodiment) In the fourth embodiment, an operation of relatively moving the optical card and the optical head in the track direction when a reproduction failure occurs is not required. Like that. Here, the number of tracks for simultaneous reproduction is also three.

In FIG. 5, reference numeral 50 denotes an optical head, on which light receiving elements 501, 502, and 503 corresponding to three tracks are mounted. The outputs of these light receiving elements 501, 502, 503 are I / V
The signals are input to conversion circuits 504, 505, and 506, and are amplified and subjected to current / voltage conversion. The outputs of the I / V conversion circuits 504 and 505 are respectively output to the binarization circuit A50.
7 and 508, and binarized. Also, I / V
The output of the conversion circuit 506 is input to a binarization circuit A 509 and a binarization circuit B 510 and binarized.

In this case, the binarization circuits A 507, 508,
Reference numeral 509 designates an edge detection method that employs a characteristic that the duty ratio of a reproduced signal is 50% to control a slice level to perform binarization, and a binarization circuit B510 uses an edge detection method. A differential method is employed in which the peak of the differential waveform of the reproduced signal is detected and binarized.

The binarization circuits A 507 and A 507
8, 509 and the output of the binarization circuit B510 are:
The signal is input to the demodulation circuit 511 and demodulated. Further, these demodulated data are input to the controller 512 and stored in the memory 513, and error correction processing is performed between the controller 512 and the memory 513. As a result, the data corresponding to the light receiving elements 501, 502, and 503 are obtained. The data of the three tracks is reproduced.

In this case, in normal reproduction processing, error correction processing is performed by the binarization circuits A 507, 508, and 5.
09 is performed only on the demodulated data of the binarized signal output by the second binarization circuit B510.
Data obtained by demodulating the digitized signal is stored in the memory 513 through the controller 512, but is not subjected to error correction processing.

Thus, in such a configuration, it is assumed that a reproduction failure has occurred in one of the three tracks tried to be reproduced through the light receiving elements 501, 502, and 503. Now, assuming that the reproduction failure track is the track to which the light receiving element 503 corresponds, in this case, the data obtained by demodulating the binarized signal output by the binarization circuit B 510 is already stored in the memory 513. Then, data error correction processing is performed between the controller 512 and the memory 513, and reproduction is performed again.

When the reproduction failure track is the track corresponding to the light receiving element 501 or 502, the optical head is moved in the same manner as described with reference to FIG.
The light receiving element 503 is moved to the track where the reproduction failure has occurred, the binarized signal output from the binarization circuit B 510 is demodulated, and the error correction processing is performed, whereby the retry reproduction processing is performed.

Accordingly, in this case, if the track having the reproduction failure is the track corresponding to the light receiving element 503, the operation of moving the optical card and the optical head relatively in the track direction again is performed. In addition, since a retry operation can be performed using a binarizing circuit of a different method, the probability of being reproducible can be increased, and the reproduction speed can be increased.

In this embodiment, the light receiving element 503 is used.
Are constituted by a plurality of binarization circuits A 509 and a binarization circuit B 510 using only a different binarization circuit corresponding to.
It may be constituted by a value conversion circuit. In this way, even if a reproduction failure occurs in any of a plurality of tracks for which reproduction has been attempted, the operation of moving the optical card and the optical head relative to each other again in the track direction is not performed. Since a retry operation using a different binarization circuit can be performed, the probability of being able to be reproduced can be increased, and the reproduction speed can be further increased.

Further, in the above-described embodiment, the number of simultaneous reproductions is three, but may be more or less. In addition, a typical slice level detection method and a differential method are used as the edge detection method of the binarization circuit, but other methods of the binarization circuit, for example, A / D conversion of a reproduced signal and digital conversion into two. A method of binarizing, a method of binarizing by detecting a peak or bottom of a reproduced signal, a method of binarizing by adjusting the amplitude of a reproduced signal or a differential signal by an AGC (automatic gain control) circuit, or the like. May be used.

[0065]

As described above, according to the present invention, a retry is performed for a track in which a reproduction signal read out by one scanning operation has become a reproduction failure by using a binarizing means of a different system. Therefore, the probability of being reproducible can be increased.

Further, during normal reproduction (when reproduction failure does not occur), reproduction can be performed using the same type of binarization means for all reproduction signal processing means.
Reproduced data without variation can be obtained.

Further, the light receiving element corresponding to each track is
By switching in a direction orthogonal to the track, the binarization means of a different system is switched, so that the binarization means can be switched with a relatively simple configuration.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a first embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of a second embodiment of the present invention.

FIG. 3 is a diagram showing a schematic configuration of a third embodiment of the present invention.

FIG. 4 is a diagram showing a schematic configuration of a modification of the third embodiment.

FIG. 5 is a diagram showing a schematic configuration of a fourth embodiment of the present invention.

FIG. 6 is a diagram for explaining a slice level detection method among edge detection methods.

FIG. 7 is a diagram for explaining a differentiation method among edge detection methods.

[Explanation of symbols]

10, 20, 30, 50 ... optical head, 101, 102, 103, 201, 202, 203, 3
01, 302, 303, 501, 502, 503... Light receiving elements, 104, 105, 106, 204, 205, 206, 3
04, 305, 306, 504, 505, 506 ... I /
V conversion circuit, 107, 108, 109, 207, 208, 209, 2
10, 307-312, 321, 322, 323, 50
7, 508, 509, 510: binarization circuit, 110, 212, 316, 511: demodulation circuit, 111, 213, 317, 512: controller, 112, 215: objective lens driving means, 211, 313, 314, 315 ... selector, 513 ... memory.

Claims (3)

[Claims] An information recording medium is provided corresponding to a plurality of tracks, and readout signals of information recorded on these tracks are simultaneously read out by one scanning, and these read out readout signals are binarized. An optical information reproducing apparatus having a plurality of reproduction signal processing means for reproducing, wherein the binarization means of at least one reproduction signal processing means among the plurality of reproduction signal processing means is a binarization means of another reproduction signal processing means. And using a different type of binarization means in place of the binarization means of the reproduction signal processing means corresponding to the track in which the reproduction signal read out by the one-time scanning has a reproduction failure. An optical information reproducing apparatus for reproducing information. 2. A plurality of tracks on an information recording medium are provided corresponding to a plurality of tracks, and readout signals of information recorded on these tracks are simultaneously read out by one scan, and these readout readout signals are binarized. An optical information reproducing apparatus having a plurality of reproduction signal processing means for reproducing, wherein at least one of the plurality of reproduction signal processing circuits is a plurality of binarization means of different systems, Optical information characterized in that reproduction is performed again by using a binarization means of a different system in place of the binarization means of the reproduction signal processing means corresponding to the track in which the read reproduction signal has become a reproduction failure. Playback device. 3. The plurality of reproduction signal processing means includes a light receiving element for reading a reproduction signal of information recorded on a corresponding track, and moving the light receiving element in a direction orthogonal to the track. 3. The optical information reproducing apparatus according to claim 1, wherein the reproduction signal processing means corresponding to the failed track is switched to a different type of binarization means.