JP2002008328A - Optical head device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply and inexpensively construct a mechanism for preventing play between the frame and the main guide shaft of an optical head device. SOLUTION: The frame 6 of the optical head device 1 is formed with the main shaft sliding part 9 or sliding along the main guide shaft 7. This sliding part 9 is equipped with a pair of shaft holes 91, 92, a circular-arc sliding groove 93 for the main guide shaft, and a leaf spring 94. The main guide shaft 7 is constantly pressed against the sliding groove 93 by the leaf spring 94, which prevents the play between them. Compared with a play preventing mechanism using a roller or the like, the structure is simple, manufacturable at a low cost, and easily applicable to an existing optical head device. In addition, the structure is advantageous to thin the shape of the device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compact disc (CD) and a digital versatile disc (DVD).
More particularly, the present invention relates to an optical head device used for reproducing an optical recording medium such as an optical recording medium, and more particularly, to a mechanism for eliminating a backlash of a slide portion for moving the device frame in a radial direction of the optical recording medium.

[0002]

2. Description of the Related Art Generally, an optical head device used for reproducing an optical disk (optical recording medium) such as a CD or a DVD has
Consisting of an objective lens for converging laser light on an optical recording medium, a lens holder holding the objective lens, a lens actuator for moving the lens holder in the tracking direction and the focusing direction, and an apparatus frame on which the lens actuator is mounted. Have been.

[0003] Further, the apparatus frame can be moved in the radial direction of the optical recording disk along a pair of guide shafts.
On both sides, slide portions are formed that slide along the guide shaft. In general, the pair of guide shafts is attached to an optical disk reproducing device or the like on which the optical head device is mounted.

A mechanism for preventing rattling between a guide shaft sliding surface such as a guide shaft hole formed in a slide portion on the apparatus frame side and a guide shaft is disclosed in Japanese Utility Model Laid-Open Publication No. Sho 61 (1986). One disclosed in Japanese Patent No. 40771 is known. The mechanism disclosed herein includes a rolling element such as a roller or a ball that presses the guide shaft against the guide shaft sliding surface by a spring. Since a lateral pressure is always applied to the guide shaft by the rolling elements, it is possible to prevent rattling between the guide shaft sliding surface and the guide shaft.

[0005]

However, in such a mechanism that applies lateral pressure to the guide shaft using such rolling elements,
Since high-precision parts such as rollers and balls are used, the cost is increased. In addition, since the slide portion of the existing device frame needs to be significantly changed, it cannot be easily applied to the existing optical head device. Moreover,
Since the rollers and the like are mounted on the slide portion, it is disadvantageous for reducing the thickness of the device frame and hence the optical head device.

An object of the present invention is to propose an optical head device having an inexpensive mechanism capable of preventing rattling between a guide shaft and a guide shaft sliding surface.

Another object of the present invention is to propose an optical head device having a rattling preventing mechanism which can be easily applied to a device frame of an existing optical head device.

Another object of the present invention is to propose an optical head device provided with a rattling preventing mechanism which is advantageous for thinning.

[0009]

In order to solve the above-mentioned problems, the present invention provides a lens actuator for moving an objective lens with respect to an optical recording medium in at least one of a tracking direction and a focusing direction, and this lens actuator comprises: And a guide shaft sliding surface that slides along a guide shaft for reciprocating the device frame in a radial direction of the optical recording medium. An optical head device having a leaf spring attached to the device frame, the leaf spring being disposed at a predetermined interval with respect to the guide shaft sliding surface, and sliding with the leaf spring and the guide shaft. A state is formed in which the guide shaft that is passed between the surfaces is pressed toward the guide shaft sliding surface by the leaf spring. It is.

In the present invention, since the rattle between the guide shaft and the sliding surface of the guide shaft is prevented by using a leaf spring, the structure is simple and the manufacture can be performed at low cost. Further, since it is only necessary to attach the leaf spring to the device frame, it can be easily applied to an existing optical head device. Moreover,
Unlike the case where a rolling element such as a roller is used, it is advantageous for reducing the thickness of the optical head device.

Here, the guide shaft sliding surface may be an arc-shaped groove. In this case, if a guide shaft disengagement prevention portion bent toward the guide shaft sliding surface is formed at the tip of the leaf spring, it is sandwiched between the leaf spring and the guide shaft sliding surface. The guide shaft is preferable because it can surely prevent the risk of the guide shaft coming off from between them.

In order to reduce the contact resistance between the leaf spring and the guide shaft, the leaf spring has an arc surface which is convex with respect to the guide shaft sliding surface, and the arc surface is formed on the guide shaft. It is desirable to make contact.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an optical head device to which the present invention is applied will be described below with reference to the drawings.

FIGS. 1A and 1B are an exploded perspective view of an optical head device to which the present invention is applied, and a partial cross-sectional view taken along line bb. The optical head device 1 of the present embodiment is an optical recording disk (not shown) such as a CD or a DVD.
To reproduce the data.

The optical head device 1 includes an objective lens 3 for converging a laser beam on an optical recording medium, a lens holder 4 holding the objective lens 3, and a magnetic drive for moving the lens holder 4 in a tracking direction and a focusing direction. It comprises a lens actuator 5 of the type and an apparatus frame 6 to which the lens actuator 5 is attached.

The main frame slide section 9 and the sub-axis slide section 10 which slide along the main guide shaft 7 and the sub-guide shaft 8 so that the apparatus frame 6 can reciprocate in the radial direction of the optical recording disk. 6 are formed on both sides.

A rectangular actuator mounting hole 61 penetrating in the thickness direction of the device frame 6 is formed in which the lens actuator 5 is mounted.
The lens actuator 5 has a flat box-shaped actuator yoke 51 whose upper side is open, and the rotation slide shaft 52 of the lens holder 4 stands vertically from the center of this bottom plate portion. I have. The lens holder 4 is movable along the axis 52 in the focusing direction and is rotatable about the axis 52 in the tracking direction.

Lens actuator 5 and lens holder 4
Between them, a tracking magnetic drive circuit and a focusing magnetic drive circuit including a drive coil and a drive magnet are configured. Since these mechanisms are publicly known, further description is omitted in this specification.

Here, the main shaft slide portion 9 includes a pair of shaft holes 91 and 92 through which the main guide shaft 7 slidably passes.
An arc-shaped sliding groove 93 is provided to connect these. Therefore, the inner peripheral surface of the shaft hole and the surface of the sliding groove function as a guide shaft sliding surface.

In this embodiment, a rectangular leaf spring 94 made of a material having high slidability is disposed at a middle position between the shaft holes 91 and 92. One end of the leaf spring 94 is connected to the device frame 6.
Is attached to the surface 6a by an attachment screw 95. The distance D between the leaf spring 94 and the sliding groove 93 facing the leaf spring 94 is set to be smaller than the outer diameter of the main guide shaft 7 passing therethrough.

As a result, when the main guide shaft 7 is passed therethrough, the leaf spring 94 moves to the position 94A shown by the imaginary line in FIG.
From above to the state shown by the solid line. Therefore, as shown by the arrow, a side pressure toward the sliding groove 93 always acts by the tip portion of the leaf spring 94 in the cantilever state. Therefore, rattling between the main guide shaft 7 and the guide sliding surface is prevented.

FIG. 2 shows another example of the rattling preventing mechanism having the above-mentioned structure. In this example, the spindle slide portion 9A formed on the device frame 6A of the optical head device 1A is configured as follows. That is, the main shaft slide portion 9A has a main guide shaft slide groove 91 having a semicircular cross section.
0 is formed as a whole. Further, leaf springs 904 and 905 are arranged at both ends in the axial direction of the main guide shaft sliding groove 910, respectively.

The leaf springs 904 and 905 are arranged so as to face the main guide shaft sliding groove 910 at a predetermined interval, and one ends of the leaf springs 904 and 905 are mounted on the apparatus frame surface 6a by mounting screws 906 and 907. I have. Therefore,
The main guide shaft 7 is sandwiched between the main guide shaft sliding groove 910 and the pair of leaf springs 904, 905. Also in this example, a lateral pressure always acts on the main guide shaft 7 in the direction indicated by the arrow in FIG. 2B due to the elastic deformation of the pair of leaf springs 904 and 905. Therefore, the main guide shaft sliding groove 91
The rattling between 0 and the main guide shaft 7 is prevented.

Here, each leaf spring 904, 905 of this embodiment
The main guide shafts 904a and 905a have leading end portions bent at an angle of approximately 45 degrees toward the main guide shaft sliding groove 910. Therefore, it is possible to reliably prevent the main guide shaft 7 from coming off from the side.

The rest of the configuration of the optical head device 1A is the same as that of the optical head device 1 shown in FIG. 1, and therefore, corresponding portions are denoted by the same reference numerals and description thereof will be omitted.

The thus configured optical head device 1 of the present embodiment
In A, the same effect as in FIG. 1 can be obtained.

In addition, in this embodiment, instead of forming the shaft hole of the main guide shaft 7, a pair of leaf springs 904, 905 are provided.
And the main guide shaft 7 is interposed between the main guide shaft sliding groove 910 and the main guide shaft sliding groove 910 having a semicircular cross section.
Can be made thinner. That is, as shown in FIG. 2C, the device frame thickness D1 can be reduced as compared with the case where the shaft hole 911 is formed. Therefore, the rattling prevention mechanism of this example is extremely advantageous for reducing the thickness of the optical head device.

Next, in each of the above examples, the leaf spring 94,
In order to reduce the sliding resistance between 904 and 905 and the main guide shaft 7, it is desirable to use an arc-shaped leaf spring as shown in FIG. The leaf spring 920 is obtained by bending a leaf spring having a constant thickness in an arc shape so as to protrude toward the main guide shaft 7. By doing so, the convex arc surface 921 of the leaf spring 920 comes into point contact with the outer peripheral surface of the main guide shaft 7, so that sliding resistance between them can be reduced.

FIG. 4 shows another example of the rattling prevention mechanism shown in FIG. In this example, the leaf spring 9 of FIG.
4, a leaf spring 940 having a cross section curved in an arc shape similar to that of FIG. 3 is used, and the leaf spring 940 is disposed between the side surface 6 a of the device frame 6 of the optical head device 1 and the main guide shaft 7. It is the structure arranged in.

To fix the leaf spring 940, grooves 6b and 6c for inserting and fixing both ends of the leaf spring 940 are formed on the side surface 6a of the apparatus frame 6. The distance from both ends of the leaf spring 940 to the arc-shaped apex in contact with the central main guide shaft 7 is larger than the distance between the apparatus frame side surface 6a and the main guide shaft 7. Therefore, the leaf spring 94
The main guide shaft 7 is pushed laterally by the elastic return force of 0, so that the rattling of the main guide shaft 7 is eliminated.

The same effect as that of FIG. 1 can be obtained by the rattling prevention mechanism of this embodiment having the above-described structure. Further, as in the case shown in FIG. 3, the leaf spring 940 contacts the main guide shaft 7 in a point contact state, so that its sliding resistance can be reduced.

In addition, in this embodiment, the leaf spring 940 is set within the thickness of the device frame side surface 6a. Therefore, since the thickness of the device frame 6 does not increase, it is extremely advantageous for reducing the thickness.

[0033]

As described above, in the optical head device according to the present invention, the main guide shaft is pressed against the sliding surface of the main guide shaft formed on the device frame by the leaf spring. Prevents backlash.

Therefore, according to the present invention, the structure is simpler than that of a rattling preventing mechanism using a rolling element such as a roller or a ball, and it can be manufactured at a low cost. Further, since it is only necessary to attach a leaf spring to an existing device frame, the present invention can be easily applied to an existing optical head device without a design change or the like. Further, it is extremely advantageous for making the device thinner.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an optical head device to which the present invention is applied, and a partial cross-sectional view of a portion cut along a line bb.

FIG. 2 is a schematic plan view showing another example of the optical head device to which the present invention is applied, a partial cross-sectional view of a portion cut along the line cc, and showing that it is advantageous for thinning the device. FIG.

FIG. 3 is an explanatory view showing another example of a leaf spring.

FIG. 4 is a partial plan view showing another example of the rattling prevention mechanism of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical head device 3 Objective lens 4 Lens holder 5 Lens actuator 51 Actuator yoke 52 Sliding rotation shaft 6 Device frame 7 Main guide shaft 8 Sub guide shaft 9 Main shaft slide part 91, 92 Shaft hole 93 Sliding groove 94 Leaf spring 95 Mounting screw 10 Sub shaft slide portion 1A Optical head device 6A Device frame 9A Main shaft slide portion 904, 905 Leaf spring 904a, 905a Main guide shaft disengagement prevention portion 906, 907 Mounting screw 910 Sliding groove 920 Plate spring 921 Convex arc surface 940 Spring

Claims (4)

[Claims] 1. A lens actuator for moving an objective lens in at least one of a tracking direction and a focusing direction with respect to an optical recording medium, and a device frame to which the lens actuator is attached. An optical head device having a guide shaft sliding surface that slides along a guide shaft for reciprocating the device frame in a radial direction of the optical recording medium, comprising a leaf spring attached to the device frame. The leaf spring is disposed so as to face the guide shaft sliding surface at a predetermined interval, and the guide shaft passed between the leaf spring and the guide shaft sliding surface is moved by the leaf spring. An optical head device wherein a state in which the optical head device is pressed toward a guide shaft sliding surface is formed. 2. The optical head device according to claim 1, wherein the guide shaft sliding surface is an arc-shaped groove. 3. The optical head device according to claim 1, wherein a guide shaft slippage prevention portion bent toward the guide shaft sliding surface is formed at a tip of the leaf spring. 4. The leaf spring according to claim 1, wherein the leaf spring has an arc surface that is convex with respect to the guide shaft sliding surface, and the arc surface is provided on the guide shaft. An optical head device which is in contact with the optical head device.