JPH02149938A - Lens actuator for optical disk device - Google Patents

Abstract

PURPOSE:To effectively prevent the dirt of an objective lens accompanied with the deterioration of a recording/reproducing characteristic by providing a lens shutter which can interrupt the objective lens from the external space of a lens actuator, and the driving device. CONSTITUTION:The outgoing hole 12 of laser beams is generated on a case wall above the objective lens 11, and the lens shutter 13 for interrupting the objective lens 11 from the external space by the opening and closing of the outgoing hole 12 is provided. The lens shutter driving device 14 for performing opening and closing by the lens shutter 13 is fixed to the side part of a case 10 detached from the objective lens 11 in a direction along the recording track of an optical disk 3. The lens shutter 13 is in a closed state while the disk device is in a halt period, and the objective lens 11 is interrupted from the external space of the lens actuator 2. Thus, the dirt of the objective lens, the deterioration of the converging function of the laser beams accompanied by the dirt accompanied with deterioration of the recording/reproducing characteristic can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a lens actuator for an optical disc device used for recording/reproducing information.

(Prior Art) Optical disk devices are commonly used that modulate laser light with pulsed signals from an external information source to record binary data on a medium disk, or to reproduce/erase recorded information. There is. In this optical disc device, an objective lens is installed to converge and irradiate a laser beam for recording/reproduction onto the optical disc surface, and a lens actuator performs highly accurate positional control of this objective lens.

(Problems to be Solved by the Invention) The lens actuator of the conventional optical disc device described above has a structure in which the objective lens is constantly exposed to the space outside the lens actuator.

Therefore, the objective lens becomes dirty due to adhesion of dust floating in the external space. This contamination of the objective lens causes a problem in that the convergence function of the laser beam deteriorates and the recording/reproducing characteristics deteriorate. This dust adhesion to the objective lens is
It is thought that this progress mainly occurs with the aggregation of moisture generated when the objective lens is cooled after the recording/reproducing operation is completed.

(Means for Solving the Problems) The lens actuator of the optical disc device according to the present invention is capable of shielding the objective lens from external space by opening and closing the laser beam exit hole formed in the wall surface of the housing near the objective lens. a lens shutter, and a lens shutter drive mechanism that is formed integrally with the housing inside or outside the housing and drives the lens shutter. It is configured to be shielded from outside space.

Hereinafter, the operation of the present invention will be explained in detail together with examples.

(Embodiment) FIG. 1 is a cross-sectional view of essential parts showing the configuration of a lens actuator of an optical disc device according to an embodiment of the present invention, together with related optical heads and optical discs.
2 is a lens actuator, and 3 is an optical disk. The lens actuator 2 includes a housing 10 that houses a main body such as an objective lens and its position control mechanism, an objective lens 11,
A laser beam exit hole 12, a lens shank 13, and a lens shutter drive mechanism 14 are provided on the wall surface of the housing directly above the objective lens.

Laser light generated by an internal light source (not shown) of the optical head 1 on which the lens actuator 2 is mounted is converged by the objective lens 11 in the lens actuator 2 and passes through the laser light exit hole 12 onto the optical disk 3. irradiated with
Recording/reproducing/erasing of information is performed. A laser beam exit hole 12 is formed on the housing wall directly above the objective lens 11.
On the outside thereof, a lens shutter 13 for shielding the objective lens 11 from the outside space by opening and closing the exit hole 12.
will be installed. A lens shutter drive mechanism 14 that opens and closes the lens shutter 13 is fixed to a side portion of the housing 1O that is spaced apart from the objective lens 11 in a direction substantially along the recording trunk of the optical disc 3.

The lens shutter 13 is moved by a lens shutter drive mechanism 14 in the horizontal direction indicated by an arrow in the figure. During the operation stop period of the optical disk device, the lens shutter 13 is in the closed state shown by the broken line in the figure, and the objective lens 11 is closed.
is shielded from the external space of the lens actuator 2,
On the other hand, during the operation period of this optical disc device, the lens shutter 13 is kept open as shown by the solid line in the figure, and the optical path of the laser beam from the objective lens 11 to the optical disc 3 is secured.

FIG. 2 is a sectional view of a main part showing an example of the configuration of the lens shutter drive mechanism 14 shown in FIG. 1. FIG.

The belt 22, one end of which is connected to the output shaft 21a of the stepping motor 21, extends along the guide 23 to one end of the lens shutter 13 and is coupled thereto.

When the operation of the optical disk device is stopped, a signal is supplied to the stepping motor 21 to rotate its output shaft 21a clockwise.As the output shaft 21a rotates, the belt 22 is let out along the guide 23, and the lens shutter is rotated. 13 moves to the position shown by the broken line in the figure and enters the closed state. Furthermore, at the start of the operation of the optical disc device, a signal is supplied to the stepping motor 21 to rotate its output shaft 21a counterclockwise. As the output shaft 21a rotates, the belt 22 is wound back along the guide 23, and the lens shutter 13 moves to the position shown by the solid line in the figure.
It becomes open.

Above, the configuration in which the lens shutter and its drive mechanism are installed outside the casing that houses the main body portion has been exemplified. However, these may be installed inside the housing.

In addition, a configuration in which the laser beam exit hole is formed on a flat wall surface of the housing is illustrated. However, the wall surface of the casing forming the emission hole can also be raised or depressed in a cylindrical shape from the surrounding wall surface as necessary.

Furthermore, although a configuration in which the lens shutter and the belt for driving the lens are separate bodies has been exemplified, it is also possible to adopt a configuration in which the tip end of the belt also serves as the lens shutter.

(Effects of the Invention) As described above in detail, the lens actuator of the optical disc device according to the present invention includes the lens shutter and its drive mechanism that can shield the objective lens from the external space of the lens actuator. The objective lens can be shielded from the outside space when the apparatus is not in operation, especially when the objective lens is cooled immediately after the operation is stopped, and dust can be effectively prevented from adhering to the objective lens. As a result, contamination of the objective lens and accompanying deterioration of recording/reproducing characteristics can be effectively prevented.

Further, in the lens actuator of the optical disk device according to the present invention, the lens shutter and its drive mechanism are formed integrally with the main body portion including the objective lens and its position control unit, so that the lens actuator can be used as a subassay independent of the optical head. can be handled.

As a result, there is an advantage that the assembly work becomes easier and the yield during assembly is improved.

Furthermore, according to an embodiment of the present invention, the lens shutter drive mechanism is arranged to be spaced apart from the objective lens in a direction substantially along the recording trunk of the optical disc, so that the effective width in the radial direction of the optical disc is reduced. be done. As a result,
This has the advantage of alleviating the problem of interference that tends to occur with spindles, hubs, disk cartridges that house optical disks, etc. when accessing the optical head, and ensuring a large movable range of the optical head.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part showing the configuration of a lens actuator of an optical disk device according to an embodiment of the present invention together with related optical heads and optical disks, and FIG. 2 shows an example of the configuration of the lens shutter drive mechanism of FIG. 1. FIG. 1... Optical head, 2... Lens actuator,
3... Optical disk, 10... Position control unit, 11...
・Objective lens, 12... Laser light exit hole, 13...
- Lens shutter, 14... Lens shutter drive mechanism, 21... Stamping motor, 21a... Output shaft of stethoping motor 21, 22... One end is coupled to the output shaft of the stamping motor, and A belt 23 whose other end is connected to the lens shutter 13...belt 22
Guide to. Figure 1

Claims (2)

[Claims] (1) A housing that houses a control mechanism that controls the position of the objective lens, a laser beam exit hole formed on the wall of the housing, and an optical disk installed in the housing near the laser beam exit hole. an objective lens that converges a laser beam irradiated to the housing; a lens shutter that can shield the objective lens from external space by opening and closing an exit hole for the laser beam; and a lens shutter that is formed integrally with the housing inside or outside the housing. and a lens shutter drive mechanism for driving the lens shutter. (2) The lens actuator for an optical disc device according to claim 1, wherein the lens shutter drive mechanism is arranged at a distance from the objective lens in a direction substantially along the recording track of the optical disc.