JPH076391A - Optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To accurately reproduce information by varying the gain of a detected signal in accordance with the detected quantity of tilt by a crosstalk canceler. CONSTITUTION:A light from a semiconductor laser 1 is converted into parallel beams by a collimate lens 2 and one part of them is reflected on a beam splitter 3. This reflected light is reflected on a mirror 22 of a tilt detecting system of an optical information recording medium 5 and irradiates the medium 5, the reflected light is supplied to a light receiving element 22 and the tilt of the medium 5 is detected. This detected signal is supplied to an adder 19 of a crosstalk canceler 13. In the adder 19, gain of output signals of A/D converter 17a, 17c to be added to an output signal of a transversal filter 18 is controlled by a control signal from a coefficient control circuit 20 and a media tilt detecting signal from a differential amplifier 24 so that correlation between an output signal of the adder 19 and output signals of A/D converters 17a, 17c is made '0'.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording / reproducing apparatus such as an optical disk apparatus for reproducing information by irradiating an optical information recording medium as a minute light spot.

[0002]

2. Description of the Related Art In an optical disk device, light from a semiconductor laser is narrowed down to the diffraction limit of light by an optical pickup, and the light spot is used to read / write information from / to a target information track on the optical disk. In the optical disc, information tracks are formed in a spiral shape or a concentric shape, and the distance between the information tracks is about 1.6 μm. The size of the light spot narrowed down to the diffraction limit of light is about 1 μm, and the depth of focus is about several μm. In order to accurately read and write information on a target information track, it is necessary to accurately focus and track an optical spot of about 1 μm on an information track of 1.6 μm pitch on an optical disk. Therefore, various methods are used.

However, since the size of the light spot is large with respect to the distance between the information tracks, when information is reproduced from the target information track on the optical disc, crosstalk from the information track adjacent to the information track occurs. Occurs,
It may not be possible to accurately reproduce the information.
As a method for removing the influence of this crosstalk, as described in Japanese Patent Application Laid-Open No. 5-36083, a signal from a light receiving portion at the center of a light receiving element of three divisions is used, and crosstalk on both sides is reduced. There is a method of accurately detecting the signal of the target information track by removing the influence of the signals from the light-receiving sections on both sides, which are greatly affected.

FIG. 13 shows an example of the method. Laser light emitted from a light source 1 made of a semiconductor laser is converted into parallel light by a collimator lens 2, passes through a beam splitter 3, and is condensed by an objective lens 4 to form a minute light spot on an optical information recording medium 5 of an optical disc. Is irradiated as. The light reflected by the optical information recording medium 5 passes through the objective lens 4 again, is reflected by the beam splitter 3, and is condensed by the detection lens 6.

A part of the light condensed by the detection lens 6 passes through the beam splitter 7, passes through the cylindrical lens 8, and is received by the light receiving element 9 for detecting the focus shift.
The remaining part is reflected by the beam splitter 7. The polarization beam splitter 10 transmits the light from the beam splitter 7 to P
The light is separated into a wave and an S wave, one of which is received by the track shift detection light-receiving element 11 and the other is received by the magneto-optical signal detection light-receiving element 12.

The amount of defocus of the light spot on the optical information recording medium 5 is detected by the well-known astigmatism method using the light receiving element 9 for detecting the defocus, and the optical spot and the information track on the optical information recording medium 5 are detected. The amount of track deviation from the center is detected by the push-pull method using the track deviation detecting light-receiving element 11. This light receiving element for track deviation detection 1
As shown in FIG. 3, reference numeral 1 is a four-division light receiving element divided into four light receiving portions 11a to 11d by a dividing line in the same direction as the information track on the optical information recording medium 5.

Further, a light spot 2 on the optical information recording medium 5
1 is divided into four parts by dividing lines in the same direction as the information track corresponding to the light receiving parts 11a to 11d, and the parts 21b and 21c irradiated on the target information track and the part adjacent to the target information track are irradiated. It is divided into two parts 21a and 21d. Then, the light receiving element 11 for detecting track deviations
Means that the two light receiving portions 11b and 11c on the center side receive the reflected light from the target information track on the optical information recording medium 5 (the reflected light from the central portions 21b and 21c of the light spot 21) and the light is received on both sides. The portions 11a and 11d receive the reflected light from the portions adjacent to the target information track (the reflected light from the two side portions 21a and 21d of the light spot 21).

As shown in FIG. 2A, the light spot 21 by the semiconductor laser 1 is the information pit 5 on the optical information recording medium 5.
When a is scanned in the direction of arrow A in the figure, signals as shown in FIGS. 2B to 2D are obtained. The light receiving sections 11b and 11c output signals corresponding to the information bits 5a on the target information track, and the summing amplifier 14b outputs the signals according to these signals.
A signal as shown in (b) is obtained. Light receiving parts 11a, 11
As shown in FIGS. 2 (c) and 2 (d), d outputs a signal corresponding to the portion adjacent to the target information track.

Further, the photo-optical signal detecting light-receiving element 12 is a four-division light-receiving element divided into four light-receiving portions 12a to 12d along a dividing line in the same direction as the information track on the optical information recording medium 5, and the center is used. The two light receiving portions 12b and 12c on the side receive the reflected light from the target information track on the optical information recording medium 5, and the light receiving portions 12a and 12d on both sides receive the reflected light from the portion adjacent to the target information track. Receive light.

In the crosstalk canceller 13, the output signals of the light receiving portions 11a and 11d of the track shift detecting light receiving element 11 are amplified by the amplifiers 14a and 14c, and the output signals of the light receiving portions 11b and 11c of the track shift detecting light receiving element 11 are amplified. Are summed and amplified by the summing amplifier 14b. Further, the light receiving portions 12a, 1 of the light receiving element 12 for detecting the magneto-optical signal
The output signal of 2d is amplified by the amplifiers 15a and 15c, and the light receiving portions 12b and 1 of the light receiving element 12 for detecting the magneto-optical signal.
The output signal of 2c is additively amplified by the adding amplifier 15b.

The output signals of the light receiving portions 11b and 11c and the light receiving portions 12b and 12c that receive the reflected light from the target information track are differentially amplified by the differential amplifier 16b via the summing amplifiers 14b and 15b, and the reproduced signal is obtained. Is obtained. The output signals of the light receiving sections 11a and 12a which receive the reflected light from one of the both sides adjacent to the target information track are fed to the differential amplifier 16a via the summing amplifiers 14a and 15a.
The light receiving section 11 which receives the reflected light from the other of the both sides adjacent to the target information track.
The output signals of d and 12d are differentially amplified by the differential amplifier 16c via the summing amplifiers 14d and 15d.

The output signals of the differential amplifiers 16a to 16c are converted into digital signals by the A / D converters 17a to 17c, and the output signals of the A / D converter 17b are added via the transversal filter 18 to the adder (or (Subtractor) 19 adds with the output signals of the A / D converters 17a and 17c
The playback signal is obtained (or subtracted). Here, the transversal filter 18 sequentially delays the output signal of the A / D converter 17b by a plurality of delay circuits and extracts it as a component of a clock unit. The output signals of these delay circuits have n integrators. Add the coefficients and mix the integration results.

Further, the coefficient control circuit 20 reflects the coefficient to be added to the output signal of each delay circuit by each integrator in the transversal filter 18 from the target information track based on the output signal of the adder 19. The light is not influenced by the reflected light from the information track adjacent to the target information track, that is, the A / D converter 17
It controls so that the correlation between the output signal of b and the output signals of the A / D converters 17a and 17c becomes 0, whereby the transversal filter 18 outputs the output signal of the A / D converter 17b to the A / D converter. The correlation with the output signals of 17a and 17c is 0.
Equalize the waveform so that

Further, the coefficient control circuit 20 includes an adder 19
Of the output signals of the A / D converters 17a and 17c to be added to the output signal of the transversal filter 18 by the adder 19 based on the output signal of the Control is performed so that the correlation with the output signals of 17a and 17c becomes zero. Therefore, the adder 19
The crosstalk is removed from the reproduced signal obtained from the above.

[0015]

In the optical information recording / reproducing apparatus, the amount of crosstalk from the information track adjacent to the target information track when reproducing the information from the target information track is shown in FIGS. As shown in FIG. 9 and FIG. 10, it largely changes depending on the tilt amount of the optical information recording medium.
As shown in FIG. 11, it largely changes depending on the defocus amount (focus shift amount) of the light spot on the optical information recording medium, and further, as shown in FIGS. 11 and 12, depending on the track shift amount of the light spot on the optical information recording medium. It changes a lot.
However, conventionally, since crosstalk is removed without considering the tilt amount of the optical information recording medium, the defocus amount of the light spot, and the track shift amount, it is possible to accurately reproduce the information from the target information track. Can not.

It is an object of the present invention to provide an optical information recording / reproducing apparatus capable of improving the above-mentioned drawbacks and reproducing information accurately.

[0017]

In order to achieve the above object, the invention according to claim 1 condenses a light beam from a light source by an objective lens and irradiates the optical information recording medium as a minute light spot, In an optical information recording / reproducing apparatus for reproducing information, a main light receiving section for receiving reflected light from one information track irradiated with a minute light spot on the optical information recording medium, and the main light receiving section on the optical information recording medium. A photodetector having a sub-light-receiving section for receiving reflected light from a portion adjacent to one information track, a tilt detecting means for detecting tilt of the optical information recording medium, and a reflected light from the one information track Adding or subtracting the detection signal from the sub light receiving unit to the detection signal from the main light receiving unit so as not to be affected by the reflected light from the portion adjacent to the one information track, And a crosstalk canceller for changing the gain of the detection signal from the sub-light-receiving unit, which is added to or subtracted from the detection signal from the main light-receiving unit, in accordance with the tilt detection amount of the tilt detection unit. .

According to a second aspect of the invention, there is provided an optical information recording / reproducing apparatus for reproducing information by condensing a light beam from a light source with an objective lens and irradiating the light information recording medium as a minute light spot. A main light receiving portion for receiving reflected light from one information track irradiated with a minute light spot on the optical information recording medium, and a reflected light from a portion adjacent to the one information track on the optical information recording medium. A photodetector having a sub-light-receiving section for receiving light, a focus shift amount detecting means for detecting a focus shift amount of a light spot on the optical information recording medium, and reflected light from the one information track is the one information track. Add or subtract the detection signal from the sub-light-receiving unit to the detection signal from the main light-receiving unit so as not to be affected by reflected light from a portion adjacent to, and, The crosstalk canceller is provided for changing the gain of the detection signal from the sub-light-receiving unit, which is added to or subtracted from the detection signal from the main light-receiving unit, according to the focus-deviation amount of the focus-deviation amount detecting means. .

According to a third aspect of the invention, there is provided an optical information recording / reproducing apparatus for reproducing information by condensing a light flux from a light source by an objective lens and irradiating the light information recording medium with a minute light spot. A main light receiving portion for receiving reflected light from one information track irradiated with a minute light spot on the optical information recording medium, and a reflected light from a portion adjacent to the one information track on the optical information recording medium. A photodetector having a sub light receiving section for receiving light, a track deviation amount detecting means for detecting a track deviation amount of a light spot on the optical information recording medium, and reflected light from the one information track is the one information track. The detection signal from the main light receiving unit is added or subtracted from the detection signal from the main light receiving unit so as not to be affected by the reflected light from the portion adjacent to It is obtained by a cross-talk canceller that changes in response to the gain of the detection signal from the sub-light receiving unit that adds or subtracts the detection signal from the in-light receiving unit to track the amount of deviation of the track deviation amount detecting means.

According to a fourth aspect of the present invention, there is provided an optical information recording / reproducing apparatus for reproducing information by condensing a light beam from a light source by an objective lens and irradiating the light information recording medium with a minute light spot. A main light receiving portion for receiving reflected light from one information track irradiated with a minute light spot on the optical information recording medium, and a reflected light from a portion adjacent to the one information track on the optical information recording medium. A photodetector having a sub-light-receiving section for receiving light; a detecting means for detecting any two or more of tilt of the optical information recording medium, focus shift amount and track shift amount of a light spot on the optical information recording medium, The sub signal is added to the detection signal from the main light receiving unit so that the reflected light from the one information track is not affected by the reflected light from the portion adjacent to the one information track. The gain of the detection signal from the sub-light-receiving unit, which adds or subtracts the detection signal from the light-receiving unit and adds or subtracts from the detection signal from the main light-receiving unit, corresponds to the combination of the respective detection amounts of the detection means. It is equipped with a crosstalk canceller that changes it.

[0021]

According to the first aspect of the invention, the reflected light from one information track irradiated with a minute light spot on the optical information recording medium is received by the main light receiving section, and the one light beam on the optical information recording medium is reflected. The reflected light from the portion adjacent to the information track is received by the sub light receiving unit. Further, the tilt of the optical information recording medium is detected by the tilt detecting means. Then, the crosstalk canceller adds the detection signal from the sub light receiving unit to the detection signal from the main light receiving unit so that the reflected light from the one information track is not affected by the reflected light from the portion adjacent to the one information track. The gain of the detection signal from the sub light receiving unit that is added or subtracted and added or subtracted from the detection signal from the main light receiving unit is changed according to the tilt detection amount of the tilt detection unit.

According to the second aspect of the present invention, the reflected light from one information track irradiated with a minute light spot on the optical information recording medium is received by the main light receiving section, and the above-mentioned one on the optical information recording medium is received. The reflected light from the portion adjacent to the information track is received by the sub light receiving unit. Further, the focus shift amount of the light spot on the optical information recording medium is detected by the focus shift amount detecting means. The crosstalk canceller converts the detection signal from the main light receiving unit into the detection signal from the main light receiving unit so that the reflected light from the one information track is not affected by the reflected light from the portion adjacent to the one information track. Addition or subtraction, and
The gain of the detection signal from the sub light receiving unit, which is added to or subtracted from the detection signal from the main light receiving unit, is changed according to the focus shift amount of the focus shift amount detecting means.

According to the third aspect of the invention, the reflected light from one information track irradiated with a minute light spot on the optical information recording medium is received by the main light receiving portion, and the one light beam on the optical information recording medium is reflected. The reflected light from the portion adjacent to the information track is received by the sub light receiving unit. Further, the track shift amount of the light spot on the optical information recording medium is detected by the track shift amount detecting means. The crosstalk canceller converts the detection signal from the main light receiving unit into the detection signal from the sub light receiving unit so that the reflected light from the one information track is not affected by the reflected light from the portion adjacent to the one information track. Is added or subtracted, and the gain of the detection signal from the sub light receiving unit that is added to or subtracted from the detection signal from the main light receiving unit is changed in accordance with the track deviation amount of the track deviation amount detecting means.

According to the fourth aspect of the invention, the reflected light from one information track irradiated with a minute light spot on the optical information recording medium is received by the main light receiving portion, and the one light beam on the optical information recording medium is reflected. The reflected light from the portion adjacent to the information track is received by the sub light receiving unit. Further, any two or more of the tilt of the optical information recording medium, the focus shift amount and the track shift amount of the light spot on the optical information recording medium are detected by the detecting means. The crosstalk canceller converts the detection signal from the main light receiving unit into the detection signal from the sub light receiving unit so that the reflected light from the one information track is not affected by the reflected light from the portion adjacent to the one information track. Is added or subtracted, and the gain of the detection signal from the sub-light-receiving unit that is added or subtracted from the detection signal from the main light-receiving unit is changed in accordance with the combination of the respective detection amounts of the detection means.

[0025]

1 shows the first embodiment of the present invention, in which the same parts as those in FIG. 13 are designated by the same reference numerals.

In the first embodiment, in the above-mentioned optical disk device shown in FIG. 13, the light from the semiconductor laser 1 is converted into parallel light by the collimator lens 2 and partly reflected by the beam splitter 3. The reflected light from the beam splitter 3 is guided to a medium (optical information recording medium) tilt detection system, reflected by a mirror 22 and irradiated on the optical information recording medium 5, and the reflected light is received by a light receiving element 23 and is reflected by the light receiving element 23. The tilt of the information recording medium 5 is detected. As the light receiving element 23, for example, a two-divided light receiving element is used, and the output signal of each light receiving portion is differentially amplified by the differential amplifier 24 to obtain a media tilt detection signal. The media tilt detection signal from the differential amplifier 24 is output to the adder 19.

The adder 19 is an A / D converter 17a to be added to the output signal of the transversal filter 18,
The gain of the output signal of 17c is equal to the output signal of the adder 19 and A
It is controlled by the control signal from the coefficient control circuit 20 and the media tilt detection signal from the differential amplifier 24 so that the correlation with the output signals of the / D converters 17a and 17c becomes zero.

The change in the amount of crosstalk due to the tilt of the optical information recording medium 5 is as shown in FIGS. For example, when the tilt amount of the optical information recording medium 5 detected by the light receiving element 23 and the differential amplifier 24 is 20 ', only one information track on the inner circumference side of the target information track on the optical information recording medium 5 is present. The amount of crosstalk from the optical information recording medium 5
The tilt amount is larger than that in the case of 0 ', and the crosstalk amount from the information track on the outer peripheral side of the target information track on the optical information recording medium 5 is decreased.
The signal due to the reflected light from the information track on the inner peripheral side of only one target information track on the optical information recording medium 5 is sent from the differential amplifier 16a to the A / D converter 17a, and on the optical information recording medium 5. Only one signal from the information track on the outer peripheral side of the target information track is reflected by the differential amplifier 16
It is sent from c to the A / D converter 17c.

The output signal of the A / D converter 17a is the adder 1
The coefficient (gain) when added to the output signal of the transversal filter 18 at 9 is largely controlled by the media tilt detection signal from the differential amplifier 24, and the output signal of the A / D converter 17c is sent to the adder 19. The coefficient (gain) when added to the output signal of the transversal filter 18 is controlled to be small by the media tilt detection signal from the differential amplifier 24. As a result, the reproduced signal obtained from the adder 19 is free from the influence of crosstalk, and accurate information can be reproduced.

FIG. 4 shows a second embodiment of the present invention, in which the same parts as those in FIG. 1 are designated by the same reference numerals. In the second embodiment, the mirror 22, the light receiving element 23 and the differential amplifier 24 are omitted from the first embodiment, and the focus signal (Fo signal) from the focus shift detecting light receiving element 9 is added to the adder 19. To be The focus shift amount of the light spot on the optical information recording medium 5 is detected by the well-known astigmatism method using the focus shift detection light receiving element 9, and the Fo signal is obtained.

The adder 19 is an A / D converter 17a to be added to the output signal of the transversal filter 18,
The gain of the output signal of 17c is equal to the output signal of the adder 19 and A
It is controlled by the control signal from the coefficient control circuit 20 and the Fo signal from the focus shift detecting light receiving element 9 so that the correlation with the output signals of the / D converters 17a and 17c becomes zero.

Changes in the focus shift amount of the light spot on the optical information recording medium 5 are as shown in FIGS. 9 and 10.
For example, when the focus shift amount of +1.0 μm occurs, the crosstalk amount from the information track adjacent to the target information track on the optical information recording medium 5 becomes larger than when the focus shift amount does not occur. Therefore, in this case, the coefficient (gain) when the output signal of the A / D converter 17a is added to the output signal of the transversal filter 18 by the adder 19 is F 0 from the focus shift detection light receiving element 9. Greatly controlled by signals. Conversely, -1.0μ
When the focus shift amount of m occurs, the crosstalk amount from the information track adjacent to the target information track on the optical information recording medium 5 becomes smaller than when the focus shift amount does not occur. Therefore, in this case, the coefficient (gain) when the output signal of the A / D converter 17c is added to the output signal of the transversal filter 18 by the adder 19 is F 0 from the focus shift detection light receiving element 9. The signal is controlled to be small. As a result, the reproduced signal obtained from the adder 19 is free from the influence of crosstalk, and accurate information can be reproduced.

FIG. 5 shows a third embodiment of the present invention, in which the same parts as those in FIG. 1 are designated by the same reference numerals. In the third embodiment, the mirror 22, the light receiving element 23 and the differential amplifier 24 are omitted from the first embodiment, and the track signal (T
r signal) is added to the adder 19. Optical information recording medium 5
The amount of track deviation between the upper light spot and the center of the information track is measured by the push-pull method.
1 and the summing amplifiers 25a and 25b, and the differential amplifier 26.

The light receiving portions 11a to 11d of the track shift detecting light receiving element 11 are arranged in the radial direction crossing the information tracks on the optical information recording medium 5.
The output signal of 11b is additively amplified by the adding amplifier 25a, and the output signals of the light receiving units 11c and 11d are added and amplified by the adding amplifier 25a.
b is added and amplified, and the output signals of the addition amplifiers 25a and 25b are differentially amplified by the differential amplifier 26 to obtain a Tr signal.

The adder 19 is an A / D converter 17a to be added to the output signal of the transversal filter 18,
The gain of the output signal of 17c is equal to the output signal of the adder 19 and A
It is controlled by the control signal from the coefficient control circuit 20 and the Tr signal from the differential amplifier 26 so that the correlation with the output signals of the / D converters 17a and 17c becomes zero.

Changes in the track shift amount of the light spot on the optical information recording medium 5 are as shown in FIGS.
For example, when a track shift of 0.1 μm occurs, the crosstalk amount from the information track on the inner peripheral side of the target information track on the optical information recording medium 5 becomes smaller than that when no track shift occurs, and On the contrary, the crosstalk amount from the information track on the outer peripheral side of the target information track on the information recording medium 5 is reduced.

Therefore, the coefficient (gain) when the output signal of the A / D converter 17a is added to the output signal of the transversal filter 18 by the adder 19 depends on the media tilt detection signal from the differential amplifier 24. Smallly controlled, A
The coefficient when the output signal of the / D converter 17c is added to the output signal of the transversal filter 18 by the adder 19
The (gain) is largely controlled by the media tilt detection signal from the differential amplifier 24. As a result, the reproduced signal obtained from the adder 19 is free from the influence of crosstalk, and accurate information can be reproduced.

FIG. 6 shows a fourth embodiment of the present invention, in which the same parts as those in FIGS. 1 and 5 are designated by the same reference numerals.

In the fourth embodiment, the Tr signal obtained by the light receiving element 11 for detecting the track deviation, the summing amplifiers 25a and 25b, and the differential amplifier 26 is added by the adder in the same manner as the third embodiment in the first embodiment. 19 added. Therefore, the adder 19 outputs the gain of the output signals of the A / D converters 17a and 17c to be added to the output signal of the transversal filter 18 as in the first and third embodiments. Signal and A / D converter 17a, 17
The coefficient control circuit 2 so that the correlation with the output signal of c becomes 0
It is controlled by a control signal from 0, a media tilt detection signal from the differential amplifier 24, and a Tr signal from the differential amplifier 26. As a result, the reproduced signal obtained from the adder 19 is free from the influence of crosstalk, and accurate information can be reproduced.

In the fourth embodiment, the gain of the output signals of the A / D converters 17a and 17c to be added to the output signal of the transversal filter 18 in the adder 19 is detected by the media tilt from the differential amplifier 24. Although it is controlled by the signal and the Tr signal from the differential amplifier 26, in the fourth embodiment, the Fo signal from the focus shift detecting light receiving element 9 is added to the adder 19 as in the second embodiment.
The gain of the output signals of the A / D converters 17a and 17c to be added to the output signal of the transversal filter 18 in the adder 19 is added to the adder 19 as in the first to third embodiments. Control signal from the coefficient control circuit 20, the media tilt detection signal from the differential amplifier 24, and the light receiving element for focus shift detection so that the correlation between the output signal of the A / D converter and the output signals of the A / D converters 17a and 17c becomes zero. It may be controlled by the Fo signal from 9 and the Tr signal from the differential amplifier 26.

In the above embodiment, the differential amplifier 2
The media tilt detection signal from No. 4 and the Fo signal from the focus shift detection light receiving element 9 are added to the adder 19, and the adder 19 is added as in the first and second embodiments.
At the gain of the output signals of the A / D converters 17a and 17c to be added to the output signal of the transversal filter 18, the output signal of the adder 19 and the gain of the A / D converter 17a,
It may be controlled by the control signal from the coefficient control circuit 20, the media tilt detection signal from the differential amplifier 24, and the Fo signal from the focus shift detection light receiving element 9 so that the correlation with the output signal of 17c becomes zero. .

Further, in the above embodiment, the Fo signal from the focus shift detecting light receiving element 9, the track shift detecting light receiving element 11, the Tr signals obtained by the adding amplifiers 25a and 25b and the differential amplifier 26 are supplied to the adder 19. In the same manner as in the second and third embodiments, the gain of the output signals of the A / D converters 17a and 17c to be added to the output signal of the transversal filter 18 in the adder 19 is added to the adder 19. Output signal and A / D converter 17
It may be controlled by the control signal from the coefficient control circuit 20, the Fo signal from the light receiving element 9 for detecting the focus shift, and the Tr signal from the differential amplifier 26 so that the correlation with the output signals of a and 17c becomes zero. . Further, as the means for detecting the tilt of the optical information recording medium 5 and the means for detecting the focus shift amount and the track shift amount of the light spot on the optical information recording medium 5, known devices other than those described above may be used. .

[0043]

As described above, according to the first aspect of the present invention, the light beam from the light source is condensed by the objective lens and irradiated as a minute light spot on the optical information recording medium to reproduce the information. In the optical information recording / reproducing apparatus, a main light receiving unit for receiving reflected light from one information track irradiated with a minute light spot on the optical information recording medium, and one main information track on the optical information recording medium. A photodetector having a sub-light-receiving part that receives reflected light from adjacent parts,
Tilt detecting means for detecting tilt of the optical information recording medium, and detection from the main light receiving unit so that reflected light from the one information track is not affected by reflected light from a portion adjacent to the one information track. The tilt detection amount of the tilt detection means is obtained by adding or subtracting the detection signal from the sub light receiving unit to the signal and adding or subtracting the detection signal from the main light receiving unit to the gain of the detection signal from the sub light receiving unit. Since the crosstalk canceller that changes in accordance with the above is provided, it is possible to reproduce the accurate information by removing the influence of the crosstalk.

According to the second aspect of the invention, there is provided an optical information recording / reproducing apparatus for reproducing information by condensing a light flux from a light source by an objective lens and irradiating the light information recording medium with a minute light spot. A main light receiving portion for receiving reflected light from one information track irradiated with a minute light spot on the optical information recording medium, reflection from a portion adjacent to the one information track on the optical information recording medium A photodetector having a sub light receiving unit for receiving light, a focus shift amount detecting means for detecting a focus shift amount of a light spot on the optical information recording medium, and a reflected light from the one information track is the one Addition or subtraction of the detection signal from the sub-light-receiving unit to the detection signal from the main light-receiving unit so as not to be affected by the reflected light from the portion adjacent to the information track, And a crosstalk canceller for changing the gain of the detection signal from the sub-light-receiving unit, which is added to or subtracted from the detection signal from the main light-receiving unit, according to the focus-deviation amount of the focus-deviation amount detecting means. , It becomes possible to reproduce the accurate information by removing the influence of crosstalk.

According to the third aspect of the invention, in the optical information recording / reproducing apparatus for reproducing information by converging the light beam from the light source by the objective lens and irradiating it as a minute light spot on the optical information recording medium. A main light receiving portion for receiving reflected light from one information track irradiated with a minute light spot on the optical information recording medium, reflection from a portion adjacent to the one information track on the optical information recording medium A photodetector having a sub light receiving section for receiving light, a track deviation amount detecting means for detecting a track deviation amount of a light spot on the optical information recording medium, and reflected light from the one information track is the one Adding or subtracting the detection signal from the sub light receiving unit to the detection signal from the main light receiving unit so as not to be affected by the reflected light from the portion adjacent to the information track, and Since a crosstalk canceller that changes the gain of the detection signal from the sub light receiving unit that is added to or subtracted from the detection signal from the main light receiving unit in accordance with the track deviation amount of the track deviation amount detecting means is provided. It becomes possible to reproduce the accurate information by removing the influence of the talk.

According to the invention described in claim 4, in the optical information recording / reproducing apparatus for reproducing information by converging the light flux from the light source by the objective lens and irradiating it as a minute light spot on the optical information recording medium. A main light receiving portion for receiving reflected light from one information track irradiated with a minute light spot on the optical information recording medium, reflection from a portion adjacent to the one information track on the optical information recording medium A photodetector having a sub-light-receiving section for receiving light, and a detection means for detecting any two or more of tilt of the optical information recording medium, focus shift amount and track shift amount of a light spot on the optical information recording medium. And a detection signal from the main light receiving unit so that reflected light from the one information track is not affected by reflected light from a portion adjacent to the one information track. The detection signal from the sub light receiving unit is added or subtracted, and the detection signal from the main light receiving unit is added or subtracted. The gain of the detection signal from the sub light receiving unit corresponds to the combination of each detection amount of the detection means. Since the crosstalk canceller for changing the information is provided, it is possible to remove the influence of the crosstalk and reproduce the information accurately.

[Brief description of drawings]

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

FIG. 2 is a diagram for explaining an example of an optical information recording / reproducing device.

FIG. 3 is a diagram showing a light receiving element for detecting track deviation and a light spot of the optical information recording / reproducing apparatus.

FIG. 4 is a schematic view showing a second embodiment of the present invention.

FIG. 5 is a schematic view showing a third embodiment of the present invention.

FIG. 6 is a schematic view showing a fourth embodiment of the present invention.

FIG. 7 is a characteristic diagram showing a relationship between an outer peripheral side medium tilt amount and a crosstalk amount of the optical information recording / reproducing apparatus.

FIG. 8 is a characteristic diagram showing a relationship between an inner peripheral side media tilt amount and a crosstalk amount of the optical information recording / reproducing apparatus.

FIG. 9 is a characteristic diagram showing a relationship between an outer peripheral side defocus amount and a crosstalk amount of the optical information recording / reproducing apparatus.

FIG. 10 is a characteristic diagram showing a relationship between an inner peripheral side defocus amount and a crosstalk amount of the optical information recording / reproducing apparatus.

FIG. 11 is a characteristic diagram showing a relationship between an outer peripheral side track shift amount and a crosstalk amount of the optical information recording / reproducing apparatus.

FIG. 12 is a characteristic diagram showing a relationship between an inner circumference side track deviation amount and a crosstalk amount of the optical information recording / reproducing apparatus.

FIG. 13 is a schematic diagram showing a configuration of the optical information recording / reproducing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 semiconductor laser 4 objective lens 5 optical information recording medium 9 light receiving element for focus shift detection 11 light receiving element for track shift detection 12 light receiving element for magneto-optical signal detection 13 crosstalk canceller 23 light receiving element for media tilt detection

Claims (4)

[Claims] 1. A light beam from a light source is condensed by an objective lens and irradiated as a minute light spot on an optical information recording medium,
In an optical information recording / reproducing apparatus for reproducing information, a main light receiving section for receiving reflected light from one information track irradiated with a minute light spot on the optical information recording medium, and the main light receiving section on the optical information recording medium. A photodetector having a sub-light-receiving section for receiving reflected light from a portion adjacent to one information track, a tilt detecting means for detecting tilt of the optical information recording medium, and a reflected light from the one information track The detection signal from the sub light receiving unit is added to or subtracted from the detection signal from the main light receiving unit so as not to be affected by the reflected light from the portion adjacent to the one information track, and the detection from the main light receiving unit is performed. A crosstalk key that changes the gain of the detection signal from the sub-light-receiving unit that is added to or subtracted from the signal in accordance with the tilt detection amount of the tilt detection means. The optical information recording and reproducing apparatus characterized by comprising a canceller. 2. A light beam from a light source is condensed by an objective lens and irradiated as a minute light spot on an optical information recording medium,
In an optical information recording / reproducing apparatus for reproducing information, a main light receiving section for receiving reflected light from one information track irradiated with a minute light spot on the optical information recording medium, and the main light receiving section on the optical information recording medium. A photodetector having a sub light receiving portion for receiving reflected light from a portion adjacent to one information track; focus shift amount detecting means for detecting a focus shift amount of a light spot on the optical information recording medium; Add or subtract a detection signal from the sub light receiving unit to a detection signal from the main light receiving unit so that the reflected light from one information track is not affected by the reflected light from a portion adjacent to the one information track; and , The gain of the detection signal from the sub-light-receiving unit, which is added to or subtracted from the detection signal from the main light-receiving unit, is adjusted by the focus shift amount detecting means. The optical information recording and reproducing apparatus is characterized in that a cross-talk canceller that changes in response to Kasuzure amount. 3. A light beam from a light source is condensed by an objective lens and irradiated as a minute light spot on an optical information recording medium,
In an optical information recording / reproducing apparatus for reproducing information, a main light receiving section for receiving reflected light from one information track irradiated with a minute light spot on the optical information recording medium, and the main light receiving section on the optical information recording medium. A photodetector having a sub light receiving portion for receiving reflected light from a portion adjacent to one information track; and a track shift amount detecting means for detecting a track shift amount of a light spot on the optical information recording medium; Add or subtract a detection signal from the sub light receiving unit to a detection signal from the main light receiving unit so that the reflected light from one information track is not affected by the reflected light from a portion adjacent to the one information track; and , The track of the track deviation amount detecting means for adding the gain of the detection signal from the sub-light-receiving unit to the addition or subtraction to the detection signal from the main light-receiving unit. The optical information recording and reproducing apparatus is characterized in that a cross-talk canceller that changes in correspondence with the record amount. 4. A light beam from a light source is condensed by an objective lens and irradiated as a minute light spot on an optical information recording medium,
In an optical information recording / reproducing apparatus for reproducing information, a main light receiving section for receiving reflected light from one information track irradiated with a minute light spot on the optical information recording medium, and the main light receiving section on the optical information recording medium. A photodetector having a sub light receiving portion for receiving reflected light from a portion adjacent to one information track, a tilt of the optical information recording medium, a focus shift amount and a track shift amount of a light spot on the optical information recording medium. Detecting means for detecting any two or more of the above;
Add or subtract a detection signal from the sub light receiving unit to a detection signal from the main light receiving unit so that the reflected light from one information track is not affected by the reflected light from a portion adjacent to the one information track; and A crosstalk canceller that changes the gain of the detection signal from the sub-light-receiving unit that is added to or subtracted from the detection signal from the main light-receiving unit, in accordance with the combination of the detection amounts of the detection means. Optical information recording / reproducing device.