JP2747076B2 - Optical head - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical head used in an optical or magneto-optical recording / reproducing apparatus.

(Prior Art) This kind of optical head has its original purpose, namely,
The disk-shaped recording medium is irradiated with a light beam to record,
When performing reproduction or erasure, it has an objective lens driving device to focus the light beam on the recording medium,
Focusing and tracking of the objective lens are performed. In addition, one optical system is configured by equipping a number of optical components accompanying this. For example, as shown in FIG. 3, a light beam from the semiconductor laser 1 is converted into a parallel light beam via a collimator lens 2 and supplied to an objective lens 4 via a polarizing beam splitter 3.
A light spot is formed on the optical disk 10 by the light condensing, and the reflected light from the optical disk 10 is reflected by the servo sensor 8 via the objective lens 4, the polarizing beam splitter 3, the condensing lens 5, and the polarizing beam splitters 6 and 7, It is configured to supply to the RF sensor 9. Here, the optical head has one optical system as a whole on the carriage 11 so that it can move in the seek direction. However, as shown in FIG. 4, a part of the optical system is separated and independent. For example, only the flip-up mirror 12 and the objective lens 4 are provided on the carriage 11, and the others are provided on the fixed head 13 side. Such a separate optical head is useful for reducing the seek time of the optical head by reducing the weight of the carriage 11.

Recently, in order to reduce the weight of the carriage 11, material conversion from aluminum or magnesium alloy to resin has been actively performed. Also, the objective lens driving device mounted on the carriage 11 has a rotary shaft of the rotary sliding type actuator directly press-fitted into the carriage and implanted, and an actuator yoke constituting a magnetic circuit is fixed from the back side of the carriage. They have also been mounted using screws.

(Problems to be Solved by the Invention) The problem here is that there is a limitation on the material of the fixing screw for the purpose of fixing the magnetic circuit, and as a result, the actuator yoke cannot be reliably fixed. That's what it means. This causes a problem that the actuator yoke resonates during use. Therefore,
Although a method of bonding an actuator yoke to a carriage is also adopted, in this case, considerable work time is required for assembly.

(Object of the Invention) The present invention has been made based on the above circumstances, and pays attention to the fact that molding is performed when the carriage is made of a synthetic resin, thereby simultaneously and reliably fixing the actuator yoke during carriage molding. An object of the present invention is to provide an optical head configured to be able to do so.

(Means for Solving the Problems) For this reason, according to the present invention, when irradiating a disk-shaped recording medium with a light beam to perform recording, reproduction or erasing,
An optical head comprising an objective lens driving device for focusing and tracking an objective lens for converging a light beam on the recording medium, and a carriage for moving the objective lens driving device in a seek direction. The carriage is made of synthetic resin, and when the carriage is molded, the actuator yoke of the magnetic circuit in the objective lens driving device is inserted and fixed.

(Operation) Therefore, it is not necessary to use the screw for fixing the magnetic circuit, the working time can be reduced, and the fixing of the actuator is reliable and there is no danger of resonance. Therefore, there is no problem in focusing and tracking. Absent.

(Embodiment) Hereinafter, an embodiment of the present invention will be specifically described with reference to FIG. 1 and FIG. Here, the tracking coil 1 is attached to the actuator bobbin 15 to which the objective lens 4 is adhered.
6, the focusing coil 17 is adhered, and the center axis 18 supporting the actuator bobbin 15 is a carriage.
11 is implanted with press-fitting or molding inserts. The magnetic circuit configured to surround the actuator bobbin 15 includes an actuator yoke 19 and an actuator magnet 20 attached to the actuator yoke 19.
When molding 11 with synthetic resin, its mounting part 19
It is fixed by inserting a. In the figure, reference numeral 2
Reference numeral 1 denotes a bearing hole for a guide rail for guiding the carriage 11 in the seek direction, and reference numerals 22 and 23 denote optical path windows provided on the optical path for the optical system. There is a hole.

In the above embodiment, the screw 24 for fixing the magnetic circuit is used in combination to further firmly fix the actuator yoke 19, but if the actuator yoke 19 can be sufficiently fixed to the carriage 11 only with the insert, the screw 24 It is not necessary to use together. Further, in the above-described embodiment, the rotary sliding type actuator is shown for focusing and tracking of the objective lens. However, it is needless to say that the present invention can be applied to all other driving systems having an actuator yoke. Further, in this embodiment, the carriage in the optical system of the separation optical type is shown, but it is needless to say that the present invention can be applied to a carriage equipped with an all-optical system.

In such a configuration, the actuator yoke 19 can be firmly fixed at the same time when the carriage 11 is formed.
Resonance is avoided during use, and high reliability can be ensured under the control of auto tracking and auto focusing.

(Effects of the Invention) The present invention has been described in detail above. When the carriage 11 is molded of synthetic resin, the actuator yoke 19 is attached with an insert, so that the working time is different from the conventional method using an adhesive. It is greatly shortened, and unlike the case of fixing only with the magnetic circuit fixing screw, it can be fixed securely and firmly, the actuator does not resonate during use, and focusing and tracking can be performed with high reliability. The effect that control can be realized is obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, FIG. 2 is an exploded perspective view of the same, and FIGS. 3 and 4 are arrangement perspective views of a conventional optical system. 4 Objective lens, 11 Carriage, 15 Actuator bobbin, 16 Tracking coil, 17 Focusing coil, 18 Center axis, 19 Actuator yoke, 19a Mounting part, 20 Actuator magnet

Claims (1)

(57) [Claims] 1. An objective lens drive for irradiating a disk-shaped recording medium with a light beam to perform focusing, tracking and an objective lens for condensing the light beam on the recording medium when performing recording, reproduction or erasing. An optical head comprising a carriage for moving the objective lens driving device in a seek direction, wherein the carriage is made of synthetic resin, and a magnetic circuit in the objective lens driving device when the carriage is molded. Optical head characterized by inserting and fixing an actuator yoke according to claim 1