JPS5956235A - Optical disc device - Google Patents

Abstract

PURPOSE:To allow the irradiation of a beam to follow up a prescribed track surely, by dividing a deflection signal to the first and the second signals and shaking a carriage mechanism and a lens by these signals, respectively. CONSTITUTION:The reflected light of a beam 14 irradiated to a disc 1 is transmitted through a lens 3, a mirror 4, a 1/4 wavelength plate 10, and a polarizing beam splitter 9 and reaches a photodetector 11 to detect the divergence between the irradiated beam and track bits, and an electric signal A is outputted. A phase compensating circuit 12 receives the electric signal A and outputs a deflection signal B so that the irradiated beam 14 follows up the eccentricity of the track. A filter circuit 15 divides the signal B to the first signal B1 of phase components for the frequency of rotation driving of the optical disc 1 and the second signal B2 of other components, and the first signal B1 is transmitted to a driving circuit 13 to drive a carriage 6 in the direction of an arrow F. The second signal B2 is transmitted to a deflecting part 3A to drive a lens 3 in the direction of the arrow F.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention In the present invention, recording and reproduction are performed by selecting a predetermined track of a rotating optical disc and irradiating it with a beam. In particular, the present invention relates to an optical disk device that performs tracking using the beam's tracking deflection signal.

(b) Prior Art and Problems An optical disk device that selects a predetermined track for recording/reproduction on a rotationally driven optical disk and irradiates a beam to perform recording/reproduction is constructed as shown in FIG. In FIG. 1, (a) is a configuration diagram of a conventional optical disk device, and (b) is an explanatory diagram of a photodetector.

The optical disc 1 is fixed to a spindle mechanism 2 and rotates as shown by arrow E. A beam output from the photoelectric device 7 is applied to the recording surface of the optical disc 1 through a lens 8. A predetermined beam 14 is emitted to a point P via a polarizing beam splitter 9, a 1/4 wavelength plate, a 10° mirror 4, and an objective lens 3.

This irradiation beam 14 is reflected by the recording surface, and the reflected light is reflected by the mirror 4. The light reaches a photodetector 11 via a V4 wavelength plate 10 and a polarizing beam splitter 9. The photodetector 11 outputs an electrical signal A based on this reflected light. Photodetector 11
As shown in (b), there are 11 points on the left and right that receive the reflected light.
It is divided into two parts, A and IIB, and under normal conditions, the amount of reflected light is equally divided on the left and right, but when the irradiation point P of the irradiation beam 14 shifts to the left and right, the amount of light changes to the left and right as shown by the dotted line 14A. There will be a difference. The phase compensation circuit 1 applies the signal A to this r.
2 receives the signal, outputs a deflection signal B to adjust the beam 14 to a location where the amount of light is equally divided into left and right parts, and slightly moves the lens 3 in the downward direction of the arrow via the deflection unit 3A. On the other hand, the irradiation means for irradiating these beams 14 is mounted on the carriage 6, and the drive circuit 13 outputs the drive signal y to the voice coil motor 5 in response to the selection signal C of the track to be recorded or reproduced. The carriage 6 is moved downward so that it is positioned on a predetermined track.

In this way, the gear ridge 6 is attached to the track to be recorded and reproduced.
is selected by the transport of the track, the Beano 14 is irradiated on that track, and the irradiation point P of the irradiation beam 14 has a phase hli (
The lens 3 is configured to be moved slightly by the ft circuit 12 to follow the track.

However, when the position of the track (crit) becomes large, even if the lens 3 is moved, there is a difference in the optical path of irradiation and reflection, making it impossible for the photodetector 11 to detect the deviation. Ta.

Therefore, in case of 311 cases where the eccentricity of the track is large, normal track deviation is not detected, so that the track servo during recording and reproduction becomes unstable.

(c) Purpose of the Invention The purpose of the present invention is to eliminate the above-mentioned problems by swinging the carriage mechanism and lens according to the eccentricity of the track so that the beam irradiation reliably follows a predetermined track. It is intended to provide.

A filter circuit is provided which receives the deflection signal and divides it into a first signal having a phase component corresponding to the frequency of rotational drive of the disk and a second signal having a phase component other than the phase component, and the first signal is transmitted to the carriage mechanism. This is achieved by an optical disk device characterized in that the drive circuit is configured to send out the (I) of the adult chicken 2 to the deflection section, respectively, so as to shake the J.

(e) Examples of the invention The present invention will be explained in detail below with reference to FIG.

FIG. 2 shows an embodiment of the optical disk device according to the present invention. (a) is a configuration 11 (b+) (by) (bs) is an explanatory diagram of a deflection signal.

A filter circuit 15 is provided which receives the multiple outputs from the phase compensation circuit 12 (fil direction No. 6 B), and the filter circuit 15 calculates the phase component with respect to the rotational frequency of the optical disc 1 in the deflection signal (3). 1 signal B1 and the remaining second signal B2 (thus, the first signal B1 is
．． 3 to drive the voice coil motor 5,
2 signal B2 is the deflection fit+ that moves the lens 3.
3A, and 1t13 has the same configuration as the conventional one. It should be noted that the same reference numerals in FIG. 1 1-1j- and FIG. 2 indicate the same objects.

The drive circuit 13 outputs a drive signal to the voice coil motor 5 in response to the selection of the track on which recording IQ is to be performed 4Nf No.C, and the voice coil motor 5 causes the carriage 6 to be moved. As a result of this transfer, the beam output from the light source 7 is transferred to the lens 8. Polarizing beam splitter 9. Quarter wave plate 10. A beam 14 illuminates a predetermined track via a mirror 4 and a lens 3.

The reflected light of this irradiated beam 14 is reflected by a lens 3, a mirror 4, a quarter wave plate 10, and a mirror 4. and polarizing beam splitter 9
The light reaches the photodetector 11 via. Using this reflected light, a deviation between the irradiation beam and the track bit is detected by the optical 4 combiner 11, and an electrical signal A is output. Phase compensation circuit 12
receives this electric signal A and outputs a deflection signal 3 so that the irradiation beam 14 follows the eccentricity of the track. For example, when the filter circuit 15 receives the deflection signal B shown in (b,), it converts it into a first signal 81 shown in (bl) of the phase component with respect to the frequency of the rotational drive of the optical disc 1 and the other signals (bs). The first signal B1 causes the eleventh movement circuit 13 to drive the delivery carriage 6 in the direction of arrow F. Further, the second signal B2 causes the deflection section 3A to drive the delivery lens 3 in the direction of arrow F.

With this configuration, tracking due to the eccentricity of the track is performed by the movement of the carriage 6 and the movement of the lens 3. The carriage 6 is used for coarse tracking, which has a large movement range, while the lens 3 is used for gradual tracking, which has a small movement range. It is possible to perform tracking, and it is possible to prevent normal misalignment from being impossible to detect due to the movement range of the lens 3 as described above.

(f) As described in detail, the present invention transmits the deflection signal B to the filter circuit 1.
5 into a first signal B1 and a second signal B2, and the carriage 6 and lens 3 are moved by each signal to follow the eccentricity of the track. This allows the lens 3 to be used for minute tracking even if the track center 14 becomes large, so deviations in the irradiation beam due to track eccentricity can be detected, and reliable track servo can be achieved during recording and playback as in the past. The practical effects obtained are great.

[Brief explanation of drawings]

In FIG. 1, (a) is a block diagram of a conventional optical disc device 1a. (b) is an explanatory diagram of a photodetector, and FIG. 2 shows an embodiment of the optical disk device according to the present invention.
+)(b2) 0)j) shows an explanatory diagram of the deflection signal. In the figure, l is an optical disk, 2 is a spindle mechanism,
3.8 is a lens, 4 is a mirror, 5 is a voice coil motor, 6 is a carriage, 7 is an optical i1Q, 9 is a (1m optical beam splitter, 10 is a V4 wavelength plate, 11 is a photodetector, 12 is a phase compensation 2 (0-) (b) 20th (α) (b3)

Claims (1)

[Claims] an optical disc that is rotationally driven; an irradiation unit that irradiates the optical disc with a predetermined beam via a deflection unit; and a photodetector that outputs electricity No. 1.4 upon reflection of the beam;
A phase compensation circuit that outputs a deflection signal instructing the deflection unit to deflect the beam and a carriage mechanism that transports the irradiation unit to a predetermined track are driven by the electric signal.
An optical disk device equipped with a drive circuit receives the deflection signal No. 16 and divides it into signals of phase components ㅅ and al with respect to the frequency of the rotational drive and a second (+=1 signal) other than the phase components. In addition to providing a filter circuit to
The signal causes the carriage mechanism to swing.
An optical disk device characterized in that the second signal is formed in one circuit so as to be sent to the 11111 facing section.