JPH0722744Y2 - Light pickup - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial application field" The present invention relates to an optical pickup for optically reading a signal of a recording medium such as a disk or a card on which magneto-optical recording or optical recording is performed, and more specifically, an optical pickup. The present invention relates to an optical pickup provided with a mechanism for preventing the optical system from vibrating in the tracking direction when the whole is moved in the tracking direction (called traverse control) such as random access.

“Prior Art” In order to prevent vibration of the optical system and actuator from occurring when the optical pickup of the conventional pickup performs traverse control, it has been proposed to perform processing such as grading the acceleration and deceleration characteristics of the optical pickup. There is.

"Problems to be solved by the device" However, in order to make traverse control even faster, it is necessary to have more rapid acceleration / deceleration characteristics.

"Means for Solving Problems" The present invention, at least, in order to prevent the optical system or the actuator from vibrating even when the entire optical pickup traverses at a high speed by the traverse mechanism,
An optical pickup that includes an optical system that optically reads a signal from a recording medium such as a disk or a card on which magneto-optical recording or optical recording has been performed, and an actuator that performs focus control and tracking control of the optical system. A restriction mechanism that allows the optical system to move in the optical axis direction and restricts the movement of the optical pickup in the traverse direction, that is, the tracking direction perpendicular to the optical axis, and holds the middle point position in the tracking control of this optical system. Provided is an optical pickup provided.

[Operation] According to the optical pickup of the present invention, the tracking servo control is released during the high speed traverse movement of the optical system, and the optical system is prevented from vibrating by being held at its midpoint state, and the traverse movement is completed. At this point, this holding is released and the tracking servo control is activated.

[Example] Next, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic view of an optical pickup showing an embodiment of the present invention, FIG. 1 (a) is a top view thereof, and FIG. 1 (b) is its A-A '.
FIG. FIG. 2 is a block diagram showing the control system of the embodiment of FIG. 1, FIG. 3 is a flow chart showing its control operation, and FIG. 4 is its access time chart, showing a comparison with the conventional one. .

FIG. 5 shows a conventional optical pickup, FIG. 5A is a perspective view thereof, FIG. 5B is a top view thereof, and FIG.

First, a conventional optical pickup and its random access will be described with reference to FIG. In FIG. 5, 1
Is an optical pickup, which is moved in the tracking direction of the disk or card by the traverse drive mechanism 21 shown in FIG. Reference numeral 2 denotes an optical system for optically reading a signal, which is fixed to a holder 3 and is connected to a column 5'of a substrate 5 by a ring spring 4 having a cushioning effect. 6 is a focus magnet fixed to the substrate 5,
Reference numeral 6 denotes a focus coil fixed to the holder 3, which moves the holder 3 in the axial direction of the shaft 8 fixed to the substrate 5 and the bearing 9 fixed to the holder 3 to cause the optical system 2 to emit light. Focus control is performed by driving in the axial direction. 7 is substrate 5
Tracking magnet fixedly mounted on the holder 7 '
The holder 3 is rotated about the axis 8 by the tracking coil provided in the above to drive the optical system 2 in the tracking direction perpendicular to the optical axis direction to perform tracking control.

Next, an embodiment of the present invention will be described with reference to FIGS. In each drawing, the same members are designated by the same reference numerals. In FIG. 1, different points from FIG. 5 will be described. Reference numeral 10 is an electromagnet core fixed to a support of the substrate 5, and 11 is an exciting coil for exciting the electromagnet core.
Reference numeral 12 is a yoke fixed to the holder 3, and its width is substantially equal to the width of the electromagnet core 10, and the length of the yoke 12 in the optical axis direction is longer than the length of the electromagnet core 10 in the vertical direction. The difference is more than the focus movement amount of the optical system 5.
These yokes 12 are arranged at positions at both ends or one end on a line connecting the shaft 8 of the holder 3 and the optical axis of the optical system 2 and close to a position facing the electromagnet core 10. . Therefore, when a current flows through the exciting coil 11, the electromagnet core 10 acts so as to absorb the yoke 12, and the movement of the holder 3 is restricted so that it cannot rotate. However, since the yoke is longer than the electromagnet core 10 in the vertical direction, even in this state, the holder 3, that is, the optical system 2 is movable in the optical axis direction, and focus control is possible. FIG. 2 shows the control system of the optical pickup of the embodiment of FIG. 1, which is well known except for the exciting coil control circuit 28, and therefore its explanation is omitted and only the part directly related to the present invention is shown in FIG. It will be described together with the flowchart of. First, when a target track is input from the input circuit 29 and a tracking signal indicating the current position from the optical pickup is input to the arithmetic circuit 23, the movement amount of the track to which the optical pickup should jump is calculated (A step, Hereinafter, it will be referred to only as A), and it is further determined here whether this movement amount is a specified value or more (B). When it is less than the specified value, normal tracking servo or normal traverse movement is performed (C). When the amount of movement is above the specified value, first turn off tracking control.
(D), current is passed through the exciting coil 11 in a state where the optical system 2 is at the center position by the ring spring 4, and the movement of the optical system 2 is regulated so as to be fixed (E). And turn on the access coil control circuit (F),
Provides fast random access. Then, while checking whether or not the target track is reached, the entire pickup continues to move at high speed (G), when the target track is reached, the current to the access coil is turned off (H), and thereafter or before or after that, the excitation coil Turn off the control circuit (I),
And the tracking control is restored (J). Since the tracking signal needs to be detected even during random access, the focus control system is constantly operating. From this stage, the normal tracking control is restored, and thereafter the tracking jump is continued (J, K, L) and the random access is ended. In the above description, the specified value of the movement amount is set to the maximum movement amount of the tracking control or more. This is because when it is smaller than that, it can be covered by the tracking servo, and when the movement is too small, the exciting coil is rather hindered from increasing the speed. By performing random access by the method described above,
For example, as schematically shown in FIG. 4, high-speed access as shown in FIG. 4B can be obtained as compared with the conventional access shown in FIG. Note that in the above description, various structures can be configured within the scope obvious from the present embodiment with respect to the mechanical portion, and the operation is turned on and off at an appropriate point in time in relation to the mechanical operation. Can be set.

[Advantage of the Invention] According to the present invention, even when the entire optical pickup traverses at a high speed by the traverse mechanism, stable and high-speed random access control can be performed without generating vibration in the optical system or the actuator.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an optical pickup used in an embodiment of the present invention. FIG. 1A is a top view thereof, and FIG.
It is a -A 'sectional view. FIG. 2 is a block diagram showing the control system of the embodiment of FIG. 1, FIG. 3 is a flow chart showing its control operation, and FIG. 4 is its access time chart. Of the present application (Fig. (B))
Shows a comparison with. FIG. 5 shows a conventional pickup, FIG. 5A is a perspective view thereof, and FIG. 5B is a top view thereof.
And FIG. 6C is a sectional view taken along the line AA '. 1 ... Optical pickup 2 ... Optical system 3 ... Holder, 4 ... Ring spring 5 ... Substrate, 6 ... Focus magnet 6 '... Focus coil 7 ... Tracking magnet 7' ... Tracking coil, 8 ...... Axis 9 ...... Bearing, 10 ...... Electromagnetic core 11 ...... Excitation coil, 12 ...... Yoke 20 ...... Optical disk, 21 ...... Traverse drive mechanism

Claims (1)

[Scope of utility model registration request] 1. An optical pickup including at least an optical system for optically reading a signal from a recording medium and an actuator for performing focus control and tracking control of the optical system, when the entire optical pickup moves in a tracking direction at high speed, In order to allow the movement of the optical system in the optical axis direction and regulate the movement of the optical pickup in the tracking direction perpendicular to the optical axis, an electromagnet is provided at a position close to the holding member of the optical system, and the electromagnet is provided. An optical pickup comprising a mechanism for sucking the holding member.