JPS58199468A - Pickup driving device of recording information reproducing device - Google Patents

Abstract

PURPOSE:To set the resonance frequency of a movable part (whole carriage) to >10KHz and to stabilize servos, by using ceramics as a bobbin material. CONSTITUTION:The carriage 1 is coupled with rails 4 through plural bearings 3 supported rotatably and pivoltally on a shaft 2 freely to move in a radius direction of a disk 9. The carriage 1 mounts a pickup 5 for reading recording information on the disk. A driving coil 6 is fitted to one flank of the carriage 1 and the coil 6 constitutes a driving means together with a magnetic circuit part 7 which produces a magnetic field linking with the coil 6 to put the carriage 1 in linear motion along the rails 4. The driving coil 6 is wounded around a bobbin 8 made of ceramics with high rigidity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pickup drive device, and more particularly to a pickup drive device in a recorded information reproducing device such as a digital audio disc player.

In digital audio disc players, etc., to drive a pickup for reading recorded information on a disc (information recording medium), a bobbin is mounted on a carriage that is equipped with the pickup and can move linearly in the radial direction of the disc. An electromagnetic drive device is used that includes a coil attached to the coil and a magnetic circuit section that generates a magnetic field that interlinks with the coil.

In such drive devices, materials with good machinability and moldability, such as aluminum and resin, have conventionally been used as bobbin materials. However, the rigidity of the bobbin, which is the part most likely to vibrate, was a problem. That is, the resonant frequency of the bobbin itself is around 2KH2, which limits the servo band, making it difficult to perform stable servo.

The present invention improves the resonant frequency of the movable part (the entire carriage) by 10
It is an object of the present invention to provide a pickup drive device for a recorded information reproducing device that enables stable servo at KHz or higher.

A pickup driving device in a recorded information reproducing apparatus according to the present invention is a combination of a coil wound around a bobbin and a magnetic circuit section that generates a magnetic field interlinked with the coil, which moves a linearly movable carriage with a pickup mounted thereon. In a configuration driven by a drive means consisting of a cage,
It is characterized by using ceramics as the bobbin material.

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

1, 2, and 3 are a partially sectional plan view, front view, and left side view showing one embodiment of the present invention. In FIG. 5, 1 is a carriage, and this carriage 1 is movable in the radial direction of the disk 9 by engaging with a rail 4 via a plurality of bearings 3 rotatably supported by a shaft 2. ing. The carriage 1 is equipped with a pickup 5 for reading information recorded on the disk, including an optical system such as an objective lens, a focus actuator for controlling the position of the optical system with respect to the disk in the optical axis direction, and the like. A drive coil 6 is attached to one side of the carriage 1, and the coil 6 constitutes a drive means together with a magnetic circuit section 7 that generates a magnetic field interlinking with the coil 6, and the coil 6 forms a drive means along the rail 4 of the carriage 1. Perform linear motion. The drive coil 6 is wound around a bobbin 8 made of highly rigid ceramics. 10
is a spindle motor for rotationally driving the disk 9,
11 is a turntable fixed to the rotating shaft of the motor 10, and 12 is a clamper for clamping the disk 9 to the turntable 11.

4 to 6 show ceramics as the bobbin material,
The gain and phase-frequency characteristics when using polycarbonate and aluminum are shown, respectively. In each figure, (a) shows the gain, and (b) shows the phase. As is clear from Figs. 4 and 5, the resonant frequency is at s, s x n z in the case of polycarbonate, and at the 4th point in the case of ceramics. Although the peak value is not indicated on the diagram, it is 15
It is around KHz. This shows the high rigidity of the ceramic bobbin. The same applies to phase rotation.

On the other hand, when aluminum is used as the bobbin material, the resonant frequency is about 15 KHz, which is almost the same value as the ceramic bin, but as is clear from Figure 6, both the gain and phase decrease as the frequency increases. It shows a gradual decreasing trend. As a result, it can be seen that aluminum is not suitable as a bobbin material because the driving device cannot be driven with a constant current.

In the above embodiment, the bearing 3 is used as the slide direction bearing, but the same performance can be obtained by using a straight bearing such as a threaded bearing.

As described in detail above, according to the present invention, by using ceramics as the bobbin material, the resonant frequency of the movable part (the entire carriage) can be made greater than IOKI (-g), which enables stable work. Another effect is that the heat generated by the coil can be effectively dissipated.

The pickup driving device according to the present invention can be used as a tracking actuator that controls the information reading spot light emitted from the pickup to accurately follow the recording track of the disk, and can also be used as a tracking actuator to control the information reading spot light emitted from the pickup to accurately follow the recording track of the disk. It can also be used as a means to control the relative position of the

[Brief explanation of drawings]

1, 2, and 3 are a plan view including a partial cross section, a front view, and a left side view showing one embodiment of the present invention, and FIGS. 4, 5, and 6 show a bobbin material. FIG. 3 is a diagram showing gain/phase-frequency characteristics when ceramic, mix, polycarbonate, and aluminum are used. Explanation of symbols of main parts 1... Carriage 4, River, Rail 5...
...Pickup 6.River...Drive coil 7...
... Magnetic Circuit Department 8 ... Bobbin Applicant Pioneer Co., Ltd. Agent Patent Attorney Motohiko Fujimura

Claims (1)

[Claims] The above-mentioned device comprises a linearly movable carriage equipped with a pickup for reading information recorded on an information recording medium, a coil wound around a bobbin, and a magnetic circuit unit that generates a magnetic field interlinked with the coil. and a drive means for driving the carriage, the bobbin being made of ceramics.