JPH0335433A - Optical disk unit - Google Patents

Abstract

PURPOSE:To exactly correct inclination by providing an amplitude detecting means to detect and calculate one or both of the amplitudes of a data signal or cross talk and an inclination correcting means to correct the inclination in the optical axis of a light beam. CONSTITUTION:An amplitude detecting means 1 detects one of the amplitude of the data signal, which is acquired by reproducing data recorded to the track of an optical disk with a pickup, and the amplitude of the cross talk part in data, which is acquired by reproducing data from the track adjacent to the track recording the data on the optical disk, or detects both of the amplitudes of the data signal and cross talk part and calculates the amplitudes. According to the output signal of this amplitude detecting means 1, the inclination in the optical axis of the light beam to be projected from the pickup to the optical disk is corrected by an inclination correcting means 2. Thus, even when there is no inclination detecting means with especially high accuracy, the inclination can be exactly corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical disk device including a magneto-optical disk device.

[Conventional technology]

In an optical disc device, a pickup irradiates a light beam onto an optical disc to record, reproduce, or erase information, but the optical axis direction of the light beam projected from the pickup onto the optical disc is tilted with respect to the direction perpendicular to the medium surface of the optical disc. , the amplitude of the information No. 73 obtained by reproducing the information recorded on the track on the optical disc with the pickup decreases, and at the same time, the amplitude of the information No. 73 obtained by reproducing the information recorded on the track on the optical disc decreases. Since the crosstalk from the source increases, the quality of the information signal deteriorates, which is undesirable.

Therefore, a tilt correction method has been proposed in which the tilt is detected and the tilt of the optical axis of the pickup is corrected based on the detection result. In the optical disk device described in Japanese Utility Model Application Publication No. 61-16719, a tilt detector extracts a signal related to rolling from the output signal of a photodetector used in a tracking servo system, and a pickup tilt correction mechanism is operated using this signal. This corrects the tilt of the optical axis of the pickup.

[Problem to be solved by the invention]

In the above optical disk device, the tilt detector extracts the signal related to the tilt from the output signal of the photodetector used in the tracking servo system and operates the pickup tilt correction mechanism using this signal. If there is an error between the optical axis direction and the optical axis direction of the light beam projected from the pickup onto the optical disk, even if the tilt detector extracts a signal related to the tilt and operates the pickup tilt correction mechanism, the optical disk medium surface may not match the optical disk direction. It is not possible to accurately correct the inclination of the optical axis of the light beam with respect to the orthogonal direction. In order to reduce the above-mentioned error, the tilt detector must be assembled with high precision, which may lead to a one-up error.

It is an object of the present invention to provide an optical disc device which can improve the above-mentioned drawbacks and can accurately perform tilt correction even without a particularly high-precision tilt detection means.

[Means to solve the problem]

In order to achieve the above object, the invention of claim t provides an optical disc device for recording and reproducing information by directly projecting a light beam onto an optical disc using a pickup. the amplitude of the data signal obtained by reproducing the recorded data by the pickup, and the crosstalk component of the data obtained by reproducing the data by the pickup from a track adjacent to the track on the optical disk where the data is recorded. amplitude detection means 1 for detecting either the amplitude of the data signal or the amplitude of the data signal and the amplitude of the crosstalk component for calculation;
and a tilt correction means 2 for correcting the tilt of the optical axis of the light beam projected from the pickup onto the optical disk based on the output signal of the amplitude detection means 1. In the optical disc device according to Item 1, as shown in FIG. 2, the amplitude detecting means ↓ includes a bandpass filter 3 having a center frequency that is substantially the same as the reproduction frequency of the recorded data, and detects the reproduction signal from the pickup. Either the amplitude of the data signal or the amplitude for the crosstalk is detected through the band pass filter 3, or the amplitude of the data signal and the amplitude for the crosstalk are detected and calculated. This is what I did.

[For production]

In the invention of claim 1, the amplitude detecting means 1 detects the amplitude of a data signal obtained by reproducing data recorded on a track on an optical disk using a pickup, and the amplitude detecting means 1 is adjacent to a track on the optical disk in which the data is recorded. The amplitude of the data obtained by reproducing the data by a pickup from the track is detected, or the amplitude of the data signal and the amplitude of the crosstalk are detected and calculated, and the amplitude is detected. The inclination of the optical axis of the light beam projected from the pickup onto the optical disk is corrected by the one-spray correction means 2 based on the output signal of the means 1.

In the invention of claim 2, the amplitude detection means 1 passes the reproduced signal from the pickup through the band pass filter 3 to detect either the amplitude of the data signal or the amplitude of the crosstalk component, or detects the amplitude of the data signal. The amplitude and the amplitude corresponding to the crosstalk are detected and calculated.

〔Example〕 FIG. 3 shows an embodiment of the invention.

In the optical disc device of this embodiment, an optical disc 11 is rotatably supported and rotationally driven by a motor, and a known pickup 12 irradiates the optical disc 11 with a light beam to record and reproduce data. During playback, the pickup 12 irradiates a light beam from a light source onto a track on the optical disk 11 via an objective lens L2a, and receives the reflected light with a light receiving element via an objective lens 12a. The data signal from the light receiving element is amplified by the amplifier 13 and sent to the host device. The data signal includes address information indicating the address on the optical disk 11, and the address detection circuit 14 separates the address information from the data signal from the amplifier 13 and sends it to the host device.

Further, the band of the data signal from the amplifier 13 is limited by a band pass filter (BPF) 15, and the amplitude is detected by an envelope detection circuit 16. The output signal of this envelope detection circuit 16 is analog/digital (
The data is A/D converted by an A/D converter 17 and read by a microcomputer (CPU) 18.

The CPU 18 operates a known tilt correction means based on the output signal of the A/D converter 17, and the tilt correction means controls the tilt of the optical axis of the data reading light beam emitted from the pickup 12.

As shown in FIG. 4, the CPU 18 sets the track n on which data is to be recorded and reproduced by the pickup 12 on the optical disc 11 to a constant value (const), for example 100, and moves the pickup 12 in the radial direction of the optical disc 11. At the same time, the optical disc 11 controls a seek motor and the like, and supplies single-frequency data to the pickup 12 to sequentially record single-frequency data on tracks n and n+2 on the optical disk 11. Here, the optical disc 11 has tracks formed concentrically or spirally, and the optical disc 11 has tracks formed in a concentric or spiral shape.
The upper track n+1 is provided between and adjacent to tracks n and n+2. Next, the CPU 1g sets the data Ti1l to be given to the tilt correction means to the negative maximum value (-MAX
), then tilt the pickup 12 to the maximum using the positive means (for example, 30'), and measure the measurement data A.
', B' are cleared.

Next, the CPU 18 controls the seek motor to seek track n and cause the pickup 12 to reproduce the single frequency data recorded on track n.

At this time, the reproduced signal from the pickup 12 is as shown in FIG.
The signal shown in a) is generated, and the CPU 18 outputs the signal from the pickup 12 to the amplifier 13. B P F 15. Envelope detection circuit 16. The amplitude ADDATA of the data signal corresponding to the single frequency data inputted via the A/D converter 17 is read and set as a variable A. Above B
The PF 15 has the same center frequency as the reproduction frequency of the single frequency data recorded on the optical disc 11.

Only the data signal corresponding to the single frequency data is passed. Next, the CPU 18 controls the seek motor to seek the track n+1, and causes the pickup 12 to reproduce the single frequency data from the track n+1 where the single frequency data is not recorded. Obtain the crosstalk amount due to data of one frequency. At this time, the reproduced signal from the pickup I2 becomes a signal as shown in FIG. B P F 1
5. Envelope detection circuit 16. A/D converter 1
The amplitude ADD of the above-mentioned crosstalk input via 7
Read ATA and set it as variable B. By comparing the difference (A-B) between the variables A and B with the difference (A'-B') between the data A' and B', the CPU 18 calculates (A-B).
Determine whether or not is the maximum value, and (A-B) is (A'-B')
If it is larger, the data Ti1l to the tilt correction means is increased by δ, for example by l', to reduce the tilt of the pickup 12. Next, the CPU 18 compares the data TiH+δ to the tilt correction means with the positive maximum value MAX, and if the data TiH+δ is larger than the positive maximum value MAX, the measured data A', B' is changed to the previous data A, B. Then, the process returns to the step of seeking track n described above.

The CPU 13 repeats this process to sequentially change the inclination of the pickup 12, and depending on the inclination of the pickup 12, the variables A and B change as shown in FIG. When (A-13) becomes less than or equal to (A'-B'), the CPU 18 corrects the inclination of the optical axis of the light beam projected from the pickup 12 onto the optical disc 11 with respect to the direction perpendicular to the medium surface of the optical disc 11. It is determined that the process has been completed and the process is terminated. Further, when the data TiH+δ to the tilt correction means reaches the positive maximum value MAX, the CPU 18 ends the process.

Note that instead of comparing (A-B) with (A'-B'), the CPU 1g determines whether A/B is the value that provides the best condition for data reproduction, or compares A with A'. By determining whether A is the maximum value or comparing B with B' to determine whether B is the minimum value, the image is projected from the pickup I2 onto the optical disc II in a direction perpendicular to the medium surface of the optical disc 11. Alternatively, it may be determined whether the inclination of the light beam in the optical axis direction has been corrected. In this case, whether the tilt in the optical axis direction of the light beam projected from the pickup 12 to the optical disc 11 with respect to the direction orthogonal to the medium surface of the optical disc 11 is corrected by combining the amplitude of the data signal and the amplitude of the crosstalk component. It is better to determine whether the optical axis direction of the light beam projected from the pickup 12 to the optical disk 11 is determined by determining whether the amplitude of the data signal or the amplitude of the crosstalk is greater than either the amplitude of the data signal or the amplitude of the crosstalk component. This is advantageous because the sensitivity to the tilt is higher than when determining whether the tilt has been corrected.

[Effects of the Invention] As described above, according to the present invention, information is recorded by irradiating a light beam onto an optical disc using a pickup.

In an optical disc device that performs reproduction, the amplitude of a data signal obtained by reproducing data recorded on a track on an optical disc using the pickup.

Either the amplitude of the crosstalk of the data obtained by reproduction by the pickup from a track adjacent to the track on which the data is recorded on the optical disk is detected, or the amplitude of the data signal and the crosstalk are detected. The present invention includes an amplitude detecting means for detecting and calculating the amplitude of the talk amount, and an amplitude correcting means for correcting the inclination of the optical axis of the light beam projected from the pickup onto the optical disk based on the output signal of the amplitude detecting means. , tilt correction can be performed accurately even without a particularly high-precision tilt detection means.

[Brief explanation of drawings]

1 and 2 are block diagrams showing each invention of claims 1 and 2, FIG. 3 is a block diagram showing an embodiment of the present invention, and FIG. 4 is a flowchart showing the operation flow of the embodiment, FIGS. 5(a) and 5(b) are waveform diagrams for explaining the same embodiment,
FIG. 6 is a characteristic diagram of the same embodiment. 1... Amplitude detection means, 2... Inclination correction means, 3...
・Bandpass filter.

Claims (1)

[Claims] 1. In an optical disc device that records and reproduces information by irradiating an optical disc with a light beam using a pickup,
the amplitude of a data signal obtained by reproducing data recorded on a track on an optical disk by the pickup; and the amplitude of a data signal obtained by reproducing data by the pickup from a track adjacent to the track on which the data is recorded on the optical disk. an amplitude detection means for detecting either one of the amplitude of the data signal and the amplitude of the crosstalk, or detecting and calculating the amplitude of the data signal and the amplitude of the crosstalk; An optical disc device comprising: tilt correction means for correcting the tilt of an optical axis of a light beam projected onto an optical disc. 2. The optical disc device according to claim 1, wherein the amplitude detection means includes a bandpass filter having a center frequency that is substantially the same as the reproduction frequency of the recorded data, and the amplitude detection means transmits the reproduction signal from the pickup to the bandpass filter. An optical disk device characterized in that either the amplitude of the data signal or the amplitude of the crosstalk component is detected through the data signal, or the amplitude of the data signal and the amplitude of the crosstalk component are detected and calculated.