JPS63161540A - Lens support - Google Patents

Abstract

PURPOSE:To prevent the vibration of the optical axis of lens by using plural plate springs arranged in the buckling direction so as to receive a force vibrating the optical axis of the lens nearly in the radial direction of the disk caused by a carrier base when it is accelerated/decelerated rapidly nearly in the radial direction of the disk. CONSTITUTION:A lens 11, a holder 13 supporting the lens 11, plural plate springs 14-14d whose one end is fixed so that the two orthogonal faces to the optical axis of the lens 11 of the holder 13 are nearly symmetrical in the radial direction of the disk 12, and the carrier base 15 to which the other end of the plate springs 14-14d is fixed to the faces nearly orthogonal to the optical axis of the lens 11 are provided. Thus, the movement of the lens 11 in the optical axis direction is attained softly and smoothly and the vibration of the lens optical axis of the carrier base due to rapid acceleration and deceleration in the disk radial direction is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a lens support device used in compact disc players, optical disc devices, and the like.

2. Description of the Related Art In recent years, compact disk players and optical disk devices have supported objective lenses with leaf springs in order to improve reliability and ease of assembly.

An example of the above-mentioned conventional lens support device will be described below with reference to the drawings.

FIG. 3 is a top view of a conventional lens support device, and FIG. 4 is a side view of FIG. 3 viewed from the direction of arrow Y. A lens 1 is held in a holder 3 and is used to focus a laser beam (not shown) onto a recording layer (not shown) of a disc 2 .

One end of a plurality of leaf springs 4a to 4d is fixed to the holder 3 on each of two surfaces substantially orthogonal to the optical axis 6-a of the lens 1 so as to be substantially symmetrical with the circumferential direction of the disk 2. The other ends of the leaf springs 4a to 4d are fixed to two surfaces of the transfer table 5 that are substantially orthogonal to the optical axis a-& of the lens 1, respectively.

Further, the transfer table 6 is moved in the approximately radial direction of the disk 2 (direction of arrow X).
It is provided movably by a drive device (not shown).

The operation of the lens support device configured as described above will be described below.

First, it is necessary for the lens 1 to follow the rotation of the disk 2, which normally has a warp, in the direction of arrow Z.

Various methods have been disclosed in the past regarding tracking error detection means and methods for tracking, so their description will be omitted here. Similarly, in order for the lens 1 to follow the tracks provided on the disk 2 or to select an arbitrary track, it is necessary to move in the direction of the arrow X and follow the arbitrary track. Since various known means can be applied, the explanation will be omitted here.

For the above operations, the leaf springs 4a to 4d are required to have characteristics that satisfy the following two items.

First, when moving lens 1 in the direction of arrow 2, lens 1
It is necessary for the leaf springs 4a to 4d to deform softly and smoothly while maintaining the optical axis a-a. Next, transfer table 6
It is necessary that the optical axis a-a of the lens 1 does not vibrate (resonate) in the direction of the arrow θ when the lens 1 rapidly accelerates or decelerates in the direction of the arrow X. From the above, the leaf springs 4a to 4d are usually metal back leaf springs with a plate thickness of 10 to 60 μm, and the shape is also 4a to 4d.
were often of the same shape.

Problems to be Solved by the Invention However, in the above configuration, the leaf springs 4a to 4 are used to soften the movement of the objective lens 1 in the two directions of the arrows.
If the thickness of the plate d is made thinner, the screw stiffness in the direction of the arrow θ decreases, so the optical axis a-a of the lens 1 vibrates (resonates) in the direction of the arrow θ due to rapid acceleration and deceleration of the transfer table 5 in the direction of the arrow ) becomes easier. This vibration deteriorates the followability when the transfer table 6 follows an arbitrary track, or in some cases makes it impossible to follow it, and causes serious drawbacks such as the ability to read information recorded on the disk 2. On the other hand, in order to reduce the above-mentioned vibration, it is effective to increase the thickness of the leaf springs 4a to 4d, but if such a measure is taken, the lens 1 will be
It is obvious that the force for following the lens 1 in the direction increases, and this results in drawbacks such as an increase in the size of the driving means (not shown) for driving the lens 1 in the two directions of the arrows, and an increase in the amount of heat generated.

In view of the above-mentioned drawbacks, the present invention has been designed so that when the lens 1 is moved in the direction of the arrow Z, the leaf springs 4a to 4d are deformed softly and smoothly while maintaining the optical axis a-a of the lens 1, and the transfer table 6 is moved in the direction of the arrow Z. The objective is to provide a lens support device in which the optical axis a-a of the lens 1 does not vibrate (resonate) in the direction of arrow 0 in response to rapid acceleration and deceleration in the X direction.

Means for Resolving the Problems In order to solve the above problems, the lens support device of the present invention includes a lens, a holder for holding the lens, and two parts of the holder that are substantially perpendicular to the optical axis of the lens. a plurality of leaf springs with one end fixed on each surface and substantially symmetrical with respect to the radial direction of the disk, and the other ends of the plurality of leaf springs on each of two surfaces substantially perpendicular to the optical axis of the lens. It has a fixed transfer platform.

Effect: With the above configuration, the present invention uses the force of the plurality of leaf springs to vibrate (resonate) the optical axis of the lens in the approximate radial direction of the disk, which is generated when the transfer table rapidly accelerates or decelerates in the approximate radial direction of the disk. Since this can be prevented by receiving the buckling in the buckling direction, the problems shown in the conventional example can be solved.

EXAMPLE Hereinafter, a lens support device according to an example of the present invention will be described with reference to the drawings. FIG. 1 is a top view of a lens support device in an embodiment of the present invention, and FIG. 2 is a side view of FIG. 1 as viewed from the direction of arrow Y. A lens 11 is held in a holder 13 to focus a laser beam (not shown) onto a recording layer (not shown) of the disk 12 . One end of a plurality of leaf springs 14a to 14d is fixed to the holder 13 on each of two surfaces substantially orthogonal to the optical axis a-a of the lens 11 so as to be substantially symmetrical with the radial direction of the disk 120. The other ends of the leaf springs 14a to 14d are fixed to two surfaces of the transfer table 16 that are substantially orthogonal to the optical axis a-a of the lens 11, respectively. In addition, the transfer table 15 has a disk 12
It is provided so as to be movable in a substantially radial direction (direction of arrow X) by a drive device (not shown).

The operation of the lens support device configured as described above and the characteristics required of the leaf springs 14a to 14d are completely the same as those of the conventional example, so a description thereof will be omitted. The difference between the conventional example and the embodiment of the present invention is that the optical axis a of the lens 11 occurs when the transfer table 16 rapidly accelerates or decelerates in the radial direction of the disk 12 (in the direction of arrow X).
-a in the direction of the arrow θ is received in the buckling direction of the plurality of leaf springs 14a to 14d. Although it depends on the dimensions and shapes of the leaf springs 14a to 14d, the rigidity in the buckling direction is generally much higher than that in the torsion direction, and experiments have also shown that the rigidity of the leaf springs 14a to 14d and the optical axis of the lens 11 When the force for vibrating a-a is the same, the amount of vibration of the optical axis a-a of the lens 11 in the direction of arrow θ in this embodiment can be significantly reduced to 1/2o to 1/60 of that of the conventional example. It could be confirmed. Therefore, with the configuration shown in this embodiment, vibration in the direction of the arrow θ of the optical axis a-a can be significantly reduced without increasing the thickness of the plurality of leaf springs 14a to 14d.

As described above, according to this embodiment, the lens 11, the holder 13 that holds the lens 11, and the two surfaces of the holder 13 that are substantially perpendicular to the optical axis a-a of the lens 11, and the disk A plurality of leaf springs 14a to 14d have one end fixed so as to be substantially symmetrical with respect to the radial direction of 12, and the other ends of the plurality of leaf springs 14a to 14d are substantially orthogonal to the optical axis a-a of the lens 11. By constructing the lens 1 with a transfer table 16 fixed to each of two surfaces
1 moves in the direction of the arrow 2, it can be smoothly and softly displaced while maintaining the optical axis a-a, and the transfer table 16
Even if the optical axis a-a suddenly accelerates or decelerates in the direction of arrow
A lens support device that is difficult to vibrate in the direction can be realized.

In this embodiment, the transfer table 16 is shown to move straight in the radial direction of the disk 12 (arrow X direction), but the lens 1
It is also effective if the disk 1 performs an arcuate motion that approximates the radial direction of the disk 12.

In addition, although the leaf springs 14a to 14d are composed of four pieces, the leaf springs 14a to 14d are
, 14b, 14C, and 14d may each be constructed from one leaf spring.

Effects of the Invention As described above, the present invention includes a lens, a holder that holds the lens, and a lens that is arranged so that each of the two surfaces of the holder perpendicular to the optical axis of the lens is substantially symmetrical with respect to the radial direction of the disk. By providing a plurality of leaf springs with one end fixed and a transfer table with the other end of the leaf spring fixed on each surface substantially perpendicular to the optical axis of the lens, movement of the lens in the optical axis direction is controlled. It can be made soft and smooth, and furthermore, vibration of the lens optical axis in the disk radial direction due to rapid acceleration/deceleration of the transfer table in the disk radial direction can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a lens support device according to an embodiment of the present invention, FIG. 2 is a side view of FIG. 1 taken from the direction of arrow Y, FIG. 3 is a plan view of a conventional lens support device, and FIG. 4 3 is a side view showing FIG. 3 from the direction of arrow Y. 11...Lens, 12.Mountain...Disc, 13
...Holder, 14a-14d...Plate spring, 15...Transfer table. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 4
Figure 1

Claims (1)

[Claims] A lens for focusing the laser beam onto the recording layer of the disk,
a holder for holding the lens; a plurality of leaf springs each having one end fixed on each of two surfaces of the holder substantially perpendicular to the optical axis of the lens and substantially symmetrical with respect to the radial direction of the disk; A lens support device comprising a transfer table on which the other ends of the plurality of leaf springs are fixed to each of two surfaces substantially perpendicular to the optical axis of the lens.