JPH04195936A - Optical head device - Google Patents

Abstract

PURPOSE:To contrive a reduction of stain on an objective lens caused by sticking of dust, etc., contained in an air flow by providing at least one vent hole communicating to the open air at the position different from that of the opening part of a cover. CONSTITUTION:The device includes the objective lens 10, an objective lens holder 11, etc., and also a vent hole 1 for detour of the air flow is provided on the outer peripheral part around the opening part 16 for lens of a cylindrical protecting cover 13 which is furnished with an opening part 16 for lens corresponding to a through-hole 17B at one end part. Consequently, the air flow generated between the objective lens 10 and the opening part 16 at the time when the holder 11 for objective lens is vertically moved, can be dispersed with detour by the air passing hole 1 as the air flow shown by the arrow 2. Thus, the reduction of stain on the objective lens 10 caused by sticking of dust, etc., contained in the air flow is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical head device, and more particularly to an optical head device in which a focal position is adjusted by driving a lens holder with tvL.

[Conventional technology]

A cross-sectional view of a conventional objective actuator is shown in FIG.

In FIG. 3, reference numeral 17 indicates a disk-shaped fixed base having a cylindrical protrusion 17A in the center and a through hole 17B in the center. A cylindrical objective lens holder 11 is disposed on the cylindrical protrusion 17A of the fixed base 17. The objective lens holder 11 has a step-shaped outer diameter with a slightly larger diameter at the lower step.

The objective lens 10 is attached to the upper end of the objective lens holder 11 in FIG. Therefore, when the objective lens holder 11 moves up and down, the objective lens 10 also moves at the same time.

Furthermore, a coil 12 is wound around the lower outer periphery of the objective lens holder 11. A magnet 15 is arranged along the outer periphery of this coil 12. A yoke 14 is similarly arranged above the magnet 15 along the coil 12.

Therefore, in the above conventional example, when the coil 12 is energized, the coil 12 and the yoke 14 depend on the direction of the energization.
Between the upward and downward direction of Figure 3! Magnetic force is generated,
By moving the objective holder 11 up and down, the objective lens 1
The focal length of 0 is adjusted.

[Problem to be solved by the invention]

On the other hand, when the objective lens is moved as described above, the air inside the protective cover 23 is moved to the point indicated by the arrow 100 in FIGS. 2(A) and 2(B).
As shown at 200, an entry/exit operation is performed to the outside.

That is, as the objective lens moves, a flow of external air flows in and out near the objective lens 10.

For this reason, dust floating in the external air is removed from the objective lens 10.
The rate at which the particles are adsorbed to the surface increases, resulting in the inconvenience that the objective lens 10 becomes dirty more quickly.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical head device that improves the disadvantages of the conventional example and reduces the amount of dust attached to an objective lens.

[Means for Solving the Problems] The present invention includes an objective lens arranged to face an optical storage medium, a lens holder that supports this objective lens, and an optical axis of the objective lens via this lens holder. an optical head device comprising: a lens drive mechanism that moves back and forth along the lens drive mechanism; and a cover that encloses the lens drive mechanism and the lens holder and has an opening for the objective lens at one end; The cover is configured to have at least one vent that communicates with the outside air at a position different from the opening.

This aims to achieve the above-mentioned purpose.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

Here, the same reference numerals are used for the same constituent members as in the conventional example described above.

FIG. 1 shows a cross-sectional view of an objective lens actuator embodying the invention.

In FIG. 1, reference numeral 17 indicates a disk-shaped fixed base having a cylindrical projection at the center and a through hole in the center.

A cylindrical objective lens holder 11 having a stepped outer diameter with a slightly larger diameter at the lower step is inserted into the cylindrical protrusion 17A of the fixed base 17 from the inner bottom side of the holder.

The objective lens holder 11 is guided up and down in the holder axis direction.

Further, an objective lens lO is attached to the upper end of the objective lens holder 11 in FIG.

Therefore, the objective lens 10 is configured to move up and down as the objective lens holder 11 moves up and down, as in the case of the conventional example described above.

On the other hand, a coil 12 is wound around the lower outer diameter portion of the objective lens holder 11, and a magnet 15 is disposed along the outer periphery of the coil 12.

Furthermore, a coil 1 is also placed above the magnet 15.
A yoke 14 is disposed around the outer periphery of 2.

Therefore, a driving force acts on the objective lens holder 11 due to the magnetic force generated by the DC current (not shown) applied to the coil 12 wound around the outer diameter of the lower part of the holder, and the 'r4 magnetic force generated by the magnet 15. , the objective lens holder is moved up and down, thereby adjusting the focal length of the objective lens 10.

Further, in this embodiment, a cylindrical protective cover 13 is provided which encloses the objective lens 10, objective lens holder 11, etc., and has a lens opening 16 at one end corresponding to the through hole 17B. . This protective cover 13
is mounted on the fixed base 17 mentioned above.

A through hole 1 for detouring the air flow is provided on the outer circumference of the protective cover 13 near the lens opening 16 described above. ).

Therefore, in this embodiment, when the objective lens holder 11 is moved up and down in the conventional example described above, the objective lens holder 11 is moved up and down.
Air flow 100,200 generated between 0 and opening 16
(see Fig. 2) can be detoured and dispersed as an air flow indicated by arrow 2 in Fig. 1 through the through hole 1, and this allows the objective lens 1 to be freed from adhesion from dust, etc. contained in the air flow.
It has the advantage of significantly reducing 0 stains.

〔Effect of the invention〕

As described above, according to the present invention, since the through-hole for air flow detour is provided in the vicinity of the objective lens optical path opening of the objective lens actuator protective cover, when the objective lens holder is moved up and down, the objective lens and the opening are This can reduce the airflow that occurs between the

As a result, the proportion of dust contained in the airflow adhering to the objective lens is greatly reduced, which can prevent it from having a significant impact on lens performance for a long period of time.
It is possible to provide an excellent optical head device that has a simple mechanism and is highly effective, which is unprecedented.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing one embodiment of the present invention, Figure 2 (A)
(B) is an explanatory diagram illustrating the movement of the conventional example, and FIG. 3 is a sectional view showing the conventional example. 1... Through-hole part as an air flow detour, 11...
...Objective lens holder as an objective lens support frame, 13...Protective cover, 16...Lens opening, 17...As an objective lens holder guide part fixed base. Applicant Nippon Electric Co., Ltd. Agent Patent Attorney Isamu Takahashi Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] (1) An objective lens arranged to face an optical storage medium, a lens holder that supports this objective lens, and a lens drive mechanism that reciprocates the objective lens along the optical axis via this lens holder. an optical head device comprising a cover that encloses the lens drive mechanism and the lens holder and has an opening for the objective lens at one end, which is different from the opening of the cover. 1. An optical head device characterized in that at least one vent hole communicating with outside air is provided at a position in which the air vent communicates with outside air.