JPH06349076A - Optical disk and recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent confliction to a disk by an object lens at the time of stop of focus operation without providing a vibration preventing section constituted with an electric circuit. CONSTITUTION:When focus operation is stopped in scanning operation, an operation indicating section 18 stops focus operation at the point of time when a current made to flow in a focus driving coil 12 of a focus control section 17 is made zero or a specified value or less. Also, when focus operation is stopped in automatic focusing operation, the operation indicating section 18 makes the focus control section 17 stop automatic focusing operation and start immediately scanning operation, after that the same processing as in scanning operation is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc recording / reproducing apparatus for preventing an objective lens from colliding with a disc.

[0002]

2. Description of the Related Art In recent years, the spread of optical disc players such as laser disc players is remarkable.

A conventional laser disc player will be described below. FIG. 5 is a block diagram of a focus function portion of a conventional laser disc player. In FIG. 5, 20 is a laser disk.
Reference numeral 21 is an objective lens that forms a light spot on the laser disk 20. Reference numeral 22 is a focus drive coil that drives the objective lens 21 to change the distance from the laser disk 20. A lens holder 23 holds the objective lens 21 and the focus drive coil 22. An optical pickup 24 is composed of a lens holder 23 and the like and reads information from the laser disk 20 by a laser. Reference numeral 25 is a support spring for movably supporting the lens holder 23 on the base of the optical pickup 24. 26
Is an error detection unit that detects the focus shift of the light spot based on the state of the signal read by the optical pickup 24. A scanning operation 27 controls the position of the objective lens 21 by passing a current through the focus drive coil 22 to change the distance from the laser disk 20 in a constant movement manner.
A focus control unit that controls each focus operation with an automatic focusing device that changes the position of the objective lens 21 so as to follow the light spot on the laser disk 20. Reference numeral 28 is an operation instruction unit that supports the focus control unit 27 to start and stop the scanning operation and the automatic focusing operation. When the focus control unit 27 stops the focus operation, reference numeral 29 gently reduces the current flowing through the focus drive coil 22 to zero without instantaneously reducing the current to zero so that the lens holder 23 does not vibrate due to the spring force of the support spring 25. It is a vibration prevention unit.

The focus operation of the laser disc player having the above structure will be described. FIG. 3 shows the scanning operation. Before the operation is started, the objective lens 21 is in a position where the gravity applied to the lens holder 23 and the spring force of the support spring are balanced. Immediately after the operation is started, the laser disk 20 is moved in the reverse direction at a high speed, and thereafter, the low speed movement in the forward direction and the reverse direction is repeated at regular intervals. FIG. 4 shows the scanning operation and the autofocus operation. When the error detection unit 26 detects that the light spot has reached on or near the laser disk 20 during the scanning operation, the operation instruction unit 28 causes the focus control unit 27 to stop the scanning operation and immediately start the automatic focusing operation. Let Focus control unit 27
Performs an automatic focusing operation using the signal of the error detection unit 26 so that the light spot is made to follow the laser disk 20.

When stopping the focus operation, the operation instructing section 28 instructs the stop regardless of the control state of the focus control section 27. However, when the focus control unit 27 instantly reduces the current flowing through the focus drive coil 22 to zero, the lens holder 23 is apart from the balanced position and is accelerated by the force of the spring of the support spring 23. There is a possibility of colliding with the laser disk 20 beyond the balance position. Therefore, the vibration prevention unit 29 gently reduces the current flowing through the focus drive coil 22 to zero to prevent collision.

[0006]

However, in the above-mentioned conventional structure, it is necessary to form the vibration preventing portion with an electric circuit, which causes a problem of increasing the cost of the device.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to prevent the collision of the objective lens with the disk when the focus operation is stopped, without providing a vibration preventing portion.

[0008]

In order to achieve this object, in the optical disc recording / reproducing apparatus of the present invention, when the focus operation is stopped during the scanning operation, the current flowing through the coil of the focus control unit is zero, or It is designed so that it is stopped when the size becomes a certain size or less.

[0009]

With this structure, the current flowing through the coil is cut off when the objective lens is in the vicinity of the balance position, so that the acceleration by the support spring does not occur and the vibration preventer is unnecessary.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to a block diagram of a focus function portion of a laser disc player.

In FIG. 1, reference numeral 10 is a laser disk. Reference numeral 11 is an objective lens that forms a light spot on the laser disk 10. Reference numeral 12 is a focus drive coil that drives the objective lens 11 and changes the distance from the laser disk 10. A lens holder 13 holds the objective lens 11 and the focus drive coil 12. 1
An optical pickup 4 is composed of a lens holder 13 and the like and reads information from the laser disk 10 by a laser. Reference numeral 15 is a support spring for movably supporting the lens holder 13 on the base of the optical pickup 14. Reference numeral 16 is an error detection unit for detecting the focus shift of the light spot from the state of the signal read by the optical pickup 14. Reference numeral 17 controls the position of the objective lens 11 by passing a current through the focus drive coil 12, and performs a scanning operation for changing the distance from the laser disk 10 in a constant movement manner, and causes the light spot to follow the laser disk 10. The focus control unit controls each focus operation such as the automatic focus operation for changing the position of the objective lens 11 as described above. Reference numeral 18 denotes an operation instructing unit that instructs the focus control unit 17 to start and stop the scanning operation and the automatic focusing operation, and when stopping the focus operation, determines the instruction timing according to the control state of the focus control unit 18. .

The focus operation of the laser disc player having the above structure will be described. The scanning operation and the autofocus operation are the same as in the conventional example. When the focus operation is stopped during the scanning operation, the operation instructing unit 18 stops it when the current flowing through the focus drive coil 12 of the focus control unit 17 becomes zero or becomes a certain magnitude or less. When stopping the focus operation during the automatic focus operation, the operation instructing unit 18 causes the focus control unit 17 to stop the automatic focus operation and immediately start the scanning operation, and thereafter performs the same processing as in the scanning operation. FIG. 2 shows how the focus operation is stopped during the autofocus operation.

As described above, according to the present embodiment, the current supplied to the focus drive coil 12 is cut off when the objective lens 11 is in the vicinity of the balance position, so that acceleration due to the support spring does not occur and the vibration preventer is unnecessary. Become.

[0014]

As described above, according to the present invention, when it is desired to stop the focusing operation during the scanning operation, the focusing operation is stopped when the current flowing through the coil of the focusing control section becomes zero or becomes a certain magnitude or less. If you want to stop the focus operation during the auto focus operation, stop the auto focus operation, start the scanning operation immediately, and then provide the operation instruction unit that performs the same processing as during the scanning operation, so that the electric circuit It is possible to realize an optical disc recording / reproducing device that does not require a vibration preventing unit.

[Brief description of drawings]

FIG. 1 is a block diagram of a focus function portion of a laser disc player according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a temporal change of the objective lens position when the focusing operation is stopped during the automatic focusing operation in the same embodiment.

FIG. 3 is a characteristic diagram showing a temporal change of an objective lens position during a scanning operation.

FIG. 4 is a characteristic diagram showing a temporal change of an objective lens position during a scanning operation and an automatic focusing operation.

FIG. 5 is a block diagram of a focus function portion of a conventional laser disc player.

[Explanation of symbols]

 10 Laser Disc 11 Objective Lens 12 Focus Drive Coil 13 Lens Holder 14 Optical Pickup 15 Support Spring 16 Error Detection Section 17 Focus Control Section 18 Operation Support Section

Claims (2)

[Claims] 1. An objective lens that forms a light spot on an optical disc and the position of the objective lens are controlled by passing a current through a coil, and the distance to the optical disc is changed in a constant manner. A focus control unit that controls each focus operation including a scanning operation and an automatic focusing operation that changes the position of the objective lens so that the light spot follows the optical disc, and the scanning operation is performed by the focus control unit. When instructing the start and stop of the automatic focus operation and stopping the focus operation during the scanning operation, the operation is stopped when the current flowing through the coil of the focus control unit becomes zero or becomes smaller than a certain magnitude. An optical disc recording / reproducing apparatus comprising an instruction unit. 2. The operation instructing unit, when stopping the focusing operation during the automatic focusing operation, stops the automatic focusing operation and immediately starts the scanning operation, and thereafter performs the same processing as that during the scanning operation. The optical disc recording / reproducing apparatus described.