JPH01138624A - Information recording and reproducing device - Google Patents

Abstract

PURPOSE:To obtain a stable tracking error signal by changing the generating system of a tracking error signal when the non-recording part of a recording support is traced and when the recorded part is traced. CONSTITUTION:When the non-recording part on an information track 1 is traced, uniform diffracted light beams are continuously obtained at a detector 3. When an optical spot 2 slips off from the track 1, the diffracted light beams are changed and a tracking error signal Sa is outputted. On the other hand, when the recorded part on the track 1 is traced, the diffracted light beams to change are obtained at the detector 3 and from both outputs of a converter 4, a signal to reduce the level is outputted. When the spot 2 slips off from the recording pit, the level of both outputs of the converter 4 is changed symmetrically. A tracking error signal Sb is outputted by both output signals of the converter 4. Thus, by changing the generating system of the error signal at the time of recording and at the time of reproducing, a stable error signal can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an information recording and reproducing device for optically recording and reproducing information, and particularly for recording and reproducing information on a recordable information recording carrier. This is related to tracking control during actual use.

[Prior Art] Conventionally, in a recordable optical information recording carrier, a guide section for tracking control is provided on the record carrier in advance, and an optical head is moved along this guide section to record data. It is configured as follows.

For example, in the case of a write-once optical disc, in order to obtain the tracking number 18 of the light beam, a flash group, a preformat pattern, etc. are provided on the disk surface in advance, and the flash group causes the incident light of the light beam to be controlled by the flash group. Diffraction is used to detect tracking errors from the light intensity distribution of diffracted light.

By the way, when information is recorded by providing bits on a record carrier like this type of write-once optical disc, the amount of diffracted light is reduced by the recording bits, so it is necessary to There is a problem in that an offset occurs in the tracking error signal when tracing and when tracing the blur group in the recorded area, and the level of the tracking error signal in the recorded area is lower than that in the unrecorded area.

FIG. 2 is a block diagram showing a conventional information recording/reproducing apparatus that takes these points into consideration.

In the figure, an information track 1 is formed of a yellow group, and a light spot 2 is divided into two in the width direction of the information track 1 by a photodetector 3 and detected. Both outputs of the detector 3 are converted into voltage signals by a current-voltage converter 4, and then processed by a differential amplifier 5 to detect high-frequency components in order to detect the light intensity distribution of the diffracted light of the information track l (i.e., the Brie group). and compare the low frequency components of both outputs.
The difference signal is output. The output of the differential amplifier 5 is amplified by an amplifier 6 and outputted from an output terminal 7 as a tracking error signal. In this amplifier 6.

Based on the switching signal input from the voltage switching circuit 8 to the switching terminal 9, the voltage Va is set during recording, and the voltage Vb is set during playback (
Va<Vb) is selectively supplied.

According to this configuration, fluctuations in the tracking error signal can be removed by switching the voltage supplied to the amplifier 6 during recording and reproducing, and giving the five-difference signal an optimal offset in each case.

[Problems to be Solved by the Invention] However, for example, when information is recorded on an optical disk with a large eccentricity, a string of recording bits may be recorded in a meandering manner with respect to an information track (brief group). In such a case, even if the information track is correctly tracked during reproduction, it cannot be said that the recorded bits are optimally tracked, and the quality of the reproduced signal will be significantly impaired.

FIG. 3 is an explanatory diagram showing such a state.

FIG. 5(A) shows a case where recording bits 10 are recorded in a meandering manner on information track 1, and FIG. 5(r3) shows a reproduced signal at that time.

Therefore, there is a problem in that simply switching the offset voltage between the unrecorded area and the low recorded area as in the conventional technique does not result in correct tracking of the recorded bits.

[Means for Solving the Problems] The information recording and reproducing apparatus according to the present invention has been made in order to solve the above problems.

In an information recording and reproducing device that optically records and reproduces information on a record carrier, when an optical head traces an unrecorded portion on the record carrier, tracking control is performed based on a guide portion formed in advance on the record carrier. The present invention is characterized in that, when tracing a low recording portion, tracking control is performed based on the recording portion recorded on the record carrier.

[Operation] In the case of tracing a recordable type record carrier, the present invention performs tracking control along a pre-formed guide part when tracing an unrecorded part of the record carrier, and traces a low recorded part. In this case, tracking control is performed along the recording section, and tracking error signals are obtained using the optimal method for each of recording and reproduction.

[Embodiment] FIG. 1 is a block diagram showing an embodiment of an information recording/reproducing apparatus according to the present invention, and the same parts as in FIG. 2 are given the same reference numerals and will be described.

In the figure, a photodetector 3 that detects a light spot 2 that is reflected light from an information track 1 divides the light spot 2 into two in the width direction of the information track 1, and each output current is converted from current to voltage. The signal is converted into a voltage signal by the device 4. Both outputs of the converter 4 are supplied to a differential amplifier 5, a detection circuit 11 and an adder circuit 12, respectively.

The output of the differential amplifier 5 is supplied to one input terminal of a switch circuit 14 via an offset adjuster 13. Further, a difference signal between both outputs of the detection circuit 11 is detected by a differential amplifier 15, and is supplied to the other input terminal of the switch circuit 14 via an offset adjuster 16. The output signal of the adder circuit 12 is connected to the control terminal of the switch circuit 14 by the signal detection circuit 17.
It is supplied through.

In an information recording and reproducing apparatus having such a configuration, first, when tracing an unrecorded part of an optical disc during recording, the detector 3 is In this case, diffracted light with a substantially uniform light intensity distribution is continuously obtained. Therefore, both outputs of the converter 4 output DC signals at a certain level. In this case, when the optical spot 2 deviates from the track 1 due to disc deviation, etc., the light intensity distribution of the diffracted light changes, and both outputs of the converter 4 change symmetrically, and the difference signal is sent to the differential amplifier 5. The signal is amplified, a predetermined level is added by the offset adjuster 13, and the signal is supplied to the switch circuit 14 as a tracking error signal Sa of the optical spot for the information track.

On the other hand, when tracing the recorded part of the optical disc during playback, since the information track 11: recorded bit is formed, the detector 3 receives diffracted light with a changing light intensity distribution, and the converter From both outputs of 4, a signal with a decreasing level is outputted to the Bit Toden in an alternating current manner.

In this case, if the light spot 2 deviates from the center of the recording bit due to meandering or the like of the recording bit, the light intensity distribution of the diffracted light changes, and the levels corresponding to the bit portions of both outputs of the converter 4 change symmetrically. The 100 output signals of the converter 4 are supplied to the detection circuit 11, and only the negative envelope signal of each signal is taken out and supplied to the differential amplifier 15. A difference signal between the two envelope signals is output from the differential amplifier 15, a predetermined level is added by the offset adjuster 16, and the signal is supplied to the switch circuit 14 as a tracking error signal sb of the optical spot with respect to the recording bit. In addition,
GC circuit +8 provided at the input stage of the detection circuit II
a, 18b and the adder 19 are circuits provided to match the reference levels of both human input signals.

Both tracking error No. 8 S obtained in this way
One of a and Sb is selected by the switch circuit 14 and outputted from the output terminal 7 to the outside.

In this case, the switching of the switch circuit 14 is performed by the adding circuit 12.
This is done by a control circuit composed of a signal detection circuit 17 and a signal detection circuit 17. The adder circuit 12 adds the 100 output signals from the converter 4, and the signal detecting circuit! 7 detects whether an AC component is present in the added output. If an AC component is present, the recorded portion is being traced, so the switch circuit 14 is switched by the output signal of the signal detection circuit I7 to select the tracking error signal sb, and if no AC component is present, the unrecorded portion is traced. Since it is in the middle, the switch circuit 14 selects the tracking error signal Sa.

[Effects of the Invention] As described in detail above, according to the information recording/reproducing apparatus according to the present invention, in a recordable record carrier, by changing the method of generating a tracking error signal between recording and reproduction, Not only is it possible to reproduce information stably, but also it is possible to obtain a tracking error signal that is stable even when the degree of modulation of the recording signal changes.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an information recording/reproducing apparatus according to the present invention, and FIG. 2 is a block diagram of a conventional information recording/reproducing apparatus. FIGS. 3(A) and 3(B) are a diagram showing a state in which recording bits are recorded in a meandering manner on an information track, and a reproduction signal diagram thereof. 1...Information track 2...Light spot 3...Photodetector 5.15...Differential amplifier 11...Detection circuit 12...Addition circuit 14...Switch circuit 17...Signal detection circuit

Claims (1)

[Claims] (1) In an information recording and reproducing device that optically records and reproduces information on a record carrier, when an optical head traces an unrecorded portion on the record carrier, it traces an unrecorded portion on the record carrier based on a guide portion formed in advance on the record carrier. An information recording and reproducing apparatus characterized in that tracking control is performed, and when tracing an already recorded part, tracking control is performed based on the recorded part recorded on the record carrier.