JPS6122440A - Optical disc reproducing device - Google Patents

Abstract

PURPOSE:To prevent the characteristic of a phase compensation circuit from giving effect on a pickup feeding motor directly by providing a switch or another phase compensation circuit at the serch mode and impression of a kick signal. CONSTITUTION:In operating the serch function, the function selecting state of an operation section is detected by a control section 31. When the serch mode of the system and impression of kick signal are detected, the control section 31 turns on a switch 30. A compensating signal S1 given to a motor drive circuit 22 does not give any effect on the characteristic of a phase compensation circuit 21. A DC voltage is superimposed on a tracking control voltage CNV in the search mode and the kick signal is superimposed in a pulsive way. The DC voltage and the kick signal are given directly to a motor drive circuit 22. Then a pickup feed motor 23 drives an actuator of the pickup section without being subject to unnecessary frequency limit, feeds the pickup section to a desired position thereby improving the acurary of the feeding position.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an optical disc reproducing device, and particularly to an improved phase compensation system for a feed motor of a pickup section.

[Technical background of the invention]

Optical disc playback devices using laser light have been developed. The pickup section of this optical disc reproducing apparatus is controlled to move along the radius from the outer circumference of the disk toward the inner circumference in order to follow the spiral recording track of the disk. In this case, since the constant linear velocity (CLV) method is adopted in the optical disc playback device, the current drive system is shown at the location of the pickup section. The pickup feed motor 23 can freely move the pickup section 13 toward the outer circumference and inner circumference of the disk 11. The reflected light from the surface of the disk 11 rotated by the disk motor 12 is input to the P, C, 7'' section 13, and this reflected light is transmitted to the objective lens 1.
4. The light is input to the light receiving section 16 via the beam splitter 15. The photoelectric conversion output of the light receiving section 16 is input to a signal processing circuit 18 including a high frequency amplification circuit and the like, and undergoes demodulation processing. The photoelectric conversion output also includes tiger and king information. This tracking information is input to the tracking servo circuit 19 and subjected to tracking error detection processing. The tracking error signal detected here is given to the tracking coil 17, and tracking control of the objective lens 14 is performed through the magnetic field generated there. As a result, the light beam of the pickup section follows the recording line.

Next, the pickup section 13 has its picker, 76
The actuator is driven by a Vicqua 76 feed motor 23. The pi, qua, f feed motor 23 is rotated by a drive voltage (DV) from the motor drive circuit 22. Therefore, by switching the polarity and magnitude of the drive voltage (DV), the rotation direction of the VIC, 76 feed motor 23,
You can change the speed. This can be done by switching the moving direction and speed of the pi, qua, g parts 13.

By the way, the drive voltage (DV) is
The speed and rotational phase of the pickup feed motor 23 can also be controlled by the phase compensation signal S1 from the pickup feed motor 23.

The phase compensation signal S1 is sent to terminal 2 of the tracking coil 17.
It is created by passing the king control voltage (CNV), which is set to 0, through the phase compensation circuit 21. Normally, tracking and king control is performed using this tracking control voltage (CNV), but the tracking coil 17
In some cases, it may not be possible to satisfy the tiger and king compensation only by controlling the position of the objective lens f14. In such a case, the picker and 7'' feed motor 23 are controlled to ensure stable operation of the tiger and king serve.

Incidentally, the tracking control voltage (CNV) in the tracking coil circuit includes not only a tracking deviation component in the drive system but also a component caused by eccentricity of the disk. There is no need to compensate for the phase of the pick-up feed motor 23 for components caused by eccentricity of the disk, and the sensor? Compensation by loop is sufficient. Therefore, a phase compensation circuit 21 is provided to prevent the pickup feed motor 23 from being fluctuated by this type of component, and the frequency component that fluctuates depending on the eccentricity is turned off by the phase compensation circuit 2.

[Problems with background technology]

By the way, in the optical disc playback device, the above-mentioned CL
Since the V system is adopted, the disk rotates quickly when the pickup section is on the outer circumference of the disk, and slow when the pickup section is on the inner circumference of the disk.

Considering this and the frequency of the component caused by the eccentricity of the disk mentioned above, if the phase compensation signal S1 to the Bi-Quatsuzo feed shimoter 23 is regulated by a phase compensation circuit with fixed characteristics as in the past, This will cause inconvenience. That is, in the connoyct disc solaya, the frequency of the component that appears in the tracking carp /I/'17 due to the eccentricity of the disc is about 4 to 8 Hz. In order to attenuate such a component by 6 dB or more in the phase compensation circuit 21, the cutoff frequency must be selected to be 2) Iz or less.

On the other hand, optical disc playback devices are provided with a random access function that allows the pickup unit to freely access any position on the disc. This is Bi, Kua, 7
This is a function to search for, for example, a music program by forwarding section a to the disk at high speed υ or forwarding it at high speed backwards.

To activate this function, operate the control panel, set it to search mode, and use the so-called kick signal.

The method used is to give it to King Koil. When a kick signal is applied to the tracking coil 17, the pickup sending motor 23 can also temporarily operate at high speed, and the pickup section can move at high speed.

However, depending on the change frequency of the kick signal, the pickup feed motor 23 may not be driven sufficiently due to the effect of the cutoff frequency characteristics of the phase compensation circuit 21 mentioned above, and the tracking coil loop may not be pulled in when returning to steady feed. There were times when I couldn't do it.

[Purpose of the invention]

This invention was made in view of the above circumstances. An object of the present invention is to provide an optical disc reproducing device capable of stabilizing the operation of a tiger or king serve after a feed motor is rotated at high speed.

[Summary of the invention]

In this invention, in the search mode, when applying the kick signal,
In order to prevent the characteristics of the phase compensation circuit 21 with different compensation purposes from directly affecting the pickup feed motor 23, a switch 30 is provided as shown in FIG. 1, or a switch 30 is provided as shown in FIG. The above object can be achieved by providing phase compensation circuits 32 and 33 for the purpose of compensation, or by providing a gain switching circuit 35 as shown in FIG.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, including a tracking coil 17, a phase compensation circuit 2, a motor drive circuit 22,
23 parts of the Quazzo feed simulator are shown. In the case of this invention, the switch 3 is connected between the input and output terminals of the phase compensation circuit 21.
0 is connected. And this switch 30 is normal! It is turned off during lay operation. Therefore, the DC offset component corresponding to the disk eccentricity that appears at the terminal 20 of the tracking coil 17 is cut off by the phase compensation circuit 21. Therefore, the rotational phase of the pickup feed motor 23 does not fluctuate due to eccentricity of the disk. The tracking coil 17 is able to control the fine movement of the objective lens to obtain the deviation caused by the eccentricity of the disk.

Next, a case will be explained in which the system's search function is activated. In this case, the control unit 31 detects the function selection state of the operating unit. When the control unit 31 detects the search mode of the system and the kick signal application state, the control unit 31 switches the switch 30.
Turn on. As a result, the compensation signal S1 given to the motor drive circuit 22 is not affected by the characteristics of the phase compensation circuit 21 in any way. In search mode,
A DC voltage is superimposed on the tracking control voltage (CNV), and a kick signal is also superimposed in the form of a pulse. In such a case, in this embodiment, the DC voltage and kick signal are directly applied to the motor drive circuit 22. Therefore, without being subject to unnecessary frequency restrictions as in the past,
The motor 23 can sufficiently drive the actuator of the pickup section and can accurately send the pickup section to a desired position. Further, since there is no influence of the phase compensation circuit 21, the selection range of the i4 pulse of the kick signal, frequency, etc. is expanded, and the accuracy of the feed position can be improved.

The present invention is not limited to the above-mentioned embodiment, but as shown in FIG. Any one optimal phase compensation circuit may be selected depending on the mode. That is, optimal phase compensation is obtained depending on the search mode, when using a kick signal, and when normal gray is used. Furthermore, as shown in Figure 3,
A gain switching circuit 35 may be provided in the motor drive circuit 22 to switch the gain when applying a kick signal and during a search mode to prevent direct influence of the output of the phase compensation circuit 21.

[Effect of revelation]

As explained above, in the present invention, when the pick-up feed motor is rotated at high speed and the big ag section moves at high speed, the subsequent tracking serve operation that is required can be stably ensured, and the reliability of the device can be improved. An optical disc playback device can be provided.

[Brief explanation of drawings]

FIG. 1 is a configuration explanatory diagram showing one embodiment of the present invention, FIGS. 2 and 3 are configuration explanatory diagrams showing other embodiments of the invention, and FIG. 4 is a conventional control section of a pickup feed shimoter. FIG. 17...Tracking coil, 21, 32° 33...
・Phase compensation circuit, 22...Motor drive circuit, 23
...Pickup feed motor, 30°34...Switch, 31...Control unit. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 3

Claims (4)

[Claims] (1) A pickup feed motor for moving the optical pickup section toward the outer and inner circumferences of the disk, a motor drive circuit that drives the pickup feed motor, and a tracking servo circuit for the tracking coil of the pickup section. give a control voltage,
When the pickup unit moves at high speed such as in a search mode, a tracking servo means for superimposing a kick signal or a DC voltage on the tracking control voltage, and a terminal of the tracking coil and an output control terminal of the motor drive circuit are provided. and a phase compensation circuit for attenuating a DC offset component of the terminal of the tracking coil caused by disc eccentricity and ensuring operation of the servo means, the optical disc reproducing device comprising: An optical disc reproducing apparatus characterized by comprising means for detecting a time of high-speed movement and preventing the output drive voltage of the motor drive circuit from being directly affected by at least the output of the phase compensation circuit. (2) The optical disk reproducing apparatus according to claim 1, wherein the means includes a switch capable of short-circuiting between the input and output terminals of the phase compensation circuit. (3) The means includes second and third phase compensation circuits that have a common input side with the phase compensation circuit and have different frequency characteristics, and an output of any one of these phase compensation circuits to the motor drive circuit. Claim 1, characterized in that the invention further comprises: a second switch for applying to the output control terminal;
The optical disc playback device described in . (4) The optical disk reproducing apparatus according to claim 1, wherein the means includes a gain switching circuit for the motor drive circuit.