JPS6215934B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pickup control mechanism for an optical disc player.

In conventional optical video disc players, in order to accurately irradiate the beam onto the track of a video disc record rotating at high speed, a tracking mirror directs the beam in the radial direction of the disc record, and a jitter correction mirror directs the beam in the tangential direction of the track. At the same time, the objective lens is also displaced in the optical axis direction of the beam. However, when the light source is reduced in size and weight from a helium neon tube to a semiconductor diode laser, it becomes possible to displace the entire pickup including the light source.

SUMMARY OF THE INVENTION Therefore, the present invention proposes a new and effective pickup control mechanism for displacing a pickup including a light source, an objective lens, and a light receiving element in the optical axis direction and the track direction.

The present invention will be explained below according to an illustrative embodiment. FIG. 1 is an exploded perspective view showing the pick-up control mechanism of this embodiment, and figure number 1 indicates a pair of first elastic surfaces 1a, 1a forming a surface parallel to the optical disc record; An elastic support made of phosphor bronze, which is formed by integrally bending a pair of second elastic surfaces 1b, 1b that are parallel to the video track and perpendicular to the first elastic surfaces 1a, 1a. A plate 2 is a fixing block that screws and fixes the ends of the second elastic surfaces 1b, 1b, 3 is a movable holder that is fixed to the first elastic surfaces 1a and supports the pick-up 4, and 5 is a movable holder that supports the pick-up 4. A focus coil 7 is fixed to the lower surface of the movable holder 3 and faces the focus field member 6 formed on the fixed block 2, and 7 is a tracking coil fixed to the side surface of the movable holder 3 and formed on the fixed block 2. A tracking coil 9 facing the field member 8 has a drive shaft 9a fixed to the fixed block 2.
Each of them shows a tracking motor for shifting the video disk player approximately in the radial direction of the video disc player.
Therefore, in this embodiment mechanism, when a focus control current is applied to the focus coil 5 based on the focus detection output obtained from the pickup 4, the focus coil 5 generates a displacement force within the focus field member 6. The pickup 4 is biased in the direction of arrow A in FIG. 2, and the pickup 4 is displaced in the optical axis direction by the deflection of the first elastic surfaces 1a, 1a. Furthermore, when a minute tracking control current is applied to the tracking coil 7 based on the tracking detection output obtained from the pickup 4, the tracking coil 7 located within the tracking field member 8 receives a displacement force and the pickup 4 The second elastic surfaces 1b, 1b are biased in the direction of arrow B in FIG.
The deflection causes the pickup to be displaced in the width direction of the video track.

In the case of this example, the displacement in the focusing direction is approximately ±1 mm, and the displacement in the tracking direction is approximately ±0.1 mm.
Although it is possible that the elastic support plate may shrink due to the deflection of the first and second elastic surfaces, in this embodiment, such shrinkage can be prevented by setting the first and second elastic surfaces to be sufficiently long. is the amount of displacement that does not actually pose a problem.

Therefore, according to this embodiment, since the elastic support plate 1 supporting the pickup 4 is allowed to be displaced in two orthogonal directions, it is possible to track the pickup and control the focus at the same time. The tracking motor 9 of this embodiment, which inputs an output obtained by averaging minute tracking control currents, rotates a fixed block in order to gradually move the pickup in the radial direction of the disc record in accordance with changes in the track playback position. However, the present invention is not limited to this configuration, and various configurations are possible. Furthermore, in this embodiment, although mechanical adjustment in the jitter direction is difficult, the jitter component can be eliminated by an electrical method, so there is no practical problem.
However, if you want to mechanically eliminate the jitter component, you can form a third elastic surface perpendicular to the first and second elastic surfaces on the elastic support plate, and also form a jitter coil and a jitter field. Needless to say, jitters can also be eliminated mechanically.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of a mechanism according to an embodiment of the present invention.
FIG. 2 shows a right side view of the same, and FIG. 3 shows a plan view of the same. Explanation of main drawing numbers, 1... Elastic support plate, 2... Fixed block, 3... Movable holder, 4... Pick up, 5... Focus coil, 7... Tracking coil, 6, 8... Field member.

Claims (1)

[Claims] 1. Each tongue of the cross-shaped flat plate is bent 90 degrees in the same direction to form a pair of first elastic surfaces parallel to the optical disk record surface and the first elastic surface along the track direction of the optical disk record. the second of the vertical pair
an elastic support plate forming an elastic surface; a fixing block that holds the elastic support plate by locking an end of one of the first or second elastic surfaces; and the first or second elastic surface. a movable holder that is locked to an end of the remaining elastic surface of the surfaces and that supports the pick-up by disposing a focus coil parallel to the first elastic surface and a tracking coil parallel to the second elastic surface; A pick-up control mechanism characterized in that a pair of field members formed on a fixed block are respectively disposed to face both of the coils.