JPH0452854Y2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Industrial Application Field The present invention relates to a pickup drive device suitable for an optical disc player.

(b) Prior Art In an optical disc player such as a compact disc player, a pick-up is moved in the radial direction with respect to a rotating disc surface, and an incident light beam emitted from a semiconductor laser in the pick-up is focused by an objective lens. , a track on the disk surface where pits and lands are formed according to the information signal is irradiated, the reflected light beam modulated by the pits and lands is reflected, and the reflected light beam is applied to a track in the pickup. A beam splitter separates the incident light beam from the incident light beam and guides it to a photodetecting element, thereby reproducing information recorded on the disk surface. In order to read out the information recorded on the disk, it is necessary to perform tracking in which the incident light beam focused by the objective lens is irradiated correctly along the track on which the information is recorded. This tracking is performed in a narrow range by moving the objective lens, but in a wide range it is performed by moving the entire pickup using a motor. Moving the entire pickup with a motor is described in, for example, Japanese Utility Model Application No. 61-33269.

(c) Problems to be solved by the invention When reading information recorded on a disk as described above, the objective lens is moved to constantly irradiate the incident light beam onto the track, and the movement of the objective lens alone is not enough to prevent the incident light beam from entering the track. When the light beam can no longer follow the track, the motor is rotated to move the entire pickup in the radial direction of the disk. However, the amount of movement of the pickup by the motor is small, and if the motor has cogging or is heavily loaded, the voltage applied to the motor increases when the motor is rotated, and the rotational energy increases. Therefore, if the motor is rotated in this state, the amount of rotation will become too large, and the amount of movement of the pickup itself will increase, making it impossible to perform accurate tracking.

The present invention relates to a pickup drive device for a disk player that eliminates the above-mentioned drawbacks.

(d) Means for Solving the Problems As described above, the disk player pick-up drive device of the present invention includes a drive gear attached to the rotating shaft of the motor, an intermediary gear that meshes with the drive gear, and the intermediary gear. The damper member includes a pick-up to which the rotational force of the motor is transmitted and is moved in the radial direction of the disk, and a damper member having a hole filled with a viscous friction agent and into which the rotating shaft of the motor is inserted.

(e) Effect Since the pick-up drive device for a disk player of the present invention has the above-described configuration, if the incident light beam becomes unable to follow the track while the objective lens in the pick-up is moved and tracking is performed, the above-mentioned A driving voltage is applied to the motor to rotate the motor and move the entire pickup in the radial direction of the disk for tracking. When the motor is rotated, the dynamic friction coefficient of the rotating shaft due to the viscous friction agent of the damper member increases, the voltage applied to the motor increases, the amount of rotation is suppressed, and the amount of movement of the pickup can be made to the required size.

(F) Embodiment An embodiment of the pickup drive device for a disk player according to the present invention will be described with reference to the drawings.

1 is a pickup, which includes a semiconductor laser, a beam splitter that separates an incident light beam emitted by the semiconductor laser and a reflected light beam reflected from the disk, and a beam splitter that focuses the beam emitted by the semiconductor laser and generates a tracking signal. A head section 2 includes an objective lens that is moved to irradiate a predetermined track, a detector that detects the beam reflected from the disk and detects various signals, and is connected to the head section 2 by an arm 3. It has a U-shaped threaded portion 4. Reference numeral 5 denotes a screw which is screwed into the screw portion 4, and the screw 5 is elongated in the radial direction of the disk and has a screw formed around it, as described in the specification and drawings of Japanese Utility Model Application No. 61-57915. 6
is an intermediary gear screwed onto the screw of the screw 5, 7 is a motor, and the intermediary gear 6 is connected to the rotating shaft 8.
It has a driving gear 9 that meshes with the rotating shaft 8.
The tip 10 of the damper member 11 is inserted into a hole 12 filled with grease. Further, the side surface of the damper member 11 is prevented from being rotated by being in contact with a cut-and-raised piece 14 formed by cutting and raising the chassis 13.

The pick-up drive device of the present invention has the above-mentioned configuration, and in order to read information recorded on the disk, the disk is rotated and the pick-up 1 is positioned on the disk surface, and an incident light beam from a semiconductor laser is emitted. Tracking is performed by irradiating along the track of the disk. This tracking is performed by moving the objective lens in response to a tracking signal in a narrow range. Tracking can be performed by moving the objective lens within a range of approximately 100 tracks; beyond that range, it is no longer possible to irradiate the incident light beam onto a predetermined track by simply moving the objective lens.
to move the entire pickup 1 in the radial direction of the disk. That is, when a driving voltage is applied to the motor 7, the rotating shaft 8 rotates, the driving gear 9 is driven, the intermediary gear 6 meshing with the driving gear 9 is rotated, and the screw 5 is rotated. When the screw 5 is rotated, the threaded portion 4 of the pick-up 1 moves in the radial direction,
The entire pickup 1 is moved in the radial direction and the incident light beam is again irradiated onto a predetermined track.

By the way, the distance that the pickup 1 must be moved by the motor 7 is as small as several 100 μm. On the other hand, the motor 7 has cogging, and a large load is applied to the rotating shaft 8 due to the intermediate gear 6 and the like, so a large rotational force is required to rotate the motor 7. Therefore, when the motor 7 starts rotating, it gains momentum and rotates, and as mentioned above, it is difficult to move the pick-up 1 by only a few hundred micrometers, and if the motor 7 rotates too much, the pick-up 1 will move more than a predetermined distance in the radial direction. However, in the present invention, as described above, the tip 10 of the rotating shaft 8 of the motor 7 is inserted into the hole 12 of the damper member 11 filled with grease, so that the dynamic friction after the rotating shaft 8 starts rotating. is increasing. Therefore, the rotational force is suppressed, the rotation of the rotating shaft 8 is reduced, and the pickup 1 is prevented from moving too much.

(g) Effects of the invention As mentioned above, in the disk player pick-up drive device of the invention, the rotating shaft of the motor is inserted into the hole of the damper member filled with a viscous friction agent, so cogging and load are large. Even if a large voltage is applied to rotate the disk, the dynamic friction after rotation is large and the pickup can be moved a predetermined distance in the radial direction of the disk.

[Brief explanation of the drawing]

FIG. 1 is a side view of the pickup drive device of the present invention, and FIG. 2 is a partial perspective view of the pickup drive device of the present invention. Explanation of the main drawings, 1... pick-up, 2...
Head part, 3... Arm, 4... Thread part, 6...
Intermediary gear, 7... Motor, 8... Rotating shaft, 9...
Drive gear, 11... Damper member, 12... Hole.

Claims (1)

[Scope of utility model registration request] A drive gear is provided on the rotation shaft of the motor, an intermediary gear is provided that meshes with the drive gear, and the rotational force of the drive gear is transmitted to the feed device of the pick-up, wherein the rotation shaft of the motor is filled with a viscous friction agent. the damper member is inserted into the hole of the damper member, and the damper member is locked with the rotation prevention member to increase the coefficient of dynamic friction of the rotating shaft of the motor and prevent the rotating shaft of the motor from rotating more than the required amount of rotation. A pick-up drive device for a disk player, which is characterized by: