JP2716749B2 - Optical system support device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a movable member for holding an optical system, which is connected to a fixed member via a plurality of elastic support members, and a movable member, that is, an optical system, by a driving member. Are driven at least in a first direction.

[Conventional technology]

Generally, in this type of optical system supporting device, in order to read information accurately, focusing which controls the distance between the optical system and the position of the information track of the optical information medium with respect to the distortion or swinging of the optical information medium. It is necessary to perform control and tracking control for controlling the optical system to follow the eccentricity of the information track. For this purpose, an optical system supporting device capable of driving the optical system in the focusing direction and the tracking direction has been proposed.

Also, as shown in FIG. 6A, for example, a conventional optical disc player is mainly a so-called “horizontal type” device 53 in which the optical axis direction of the optical system coincides with the direction of gravity. Drive control for reading has been mainly developed in this "horizontal type" device.

[Problems to be solved by the invention]

However, recently, from the viewpoint of effective use of space, as shown in FIG. 6 (B), the direction of gravity comes in a direction orthogonal to the optical axis direction of the optical system, that is, a so-called “vertical type”.
Since many devices 54 have also been produced, the following problems have arisen in the conventional optical system supporting device.

For example, in a “horizontal type” optical system supporting device, as shown in FIG.
The mounting relationship between the fixed member 44 and the fixed member 44 is such that the axis P of the coil 43 of the movable member 42 is
The permanent magnet 45 is located above the axis Q of the permanent magnet 45.

For this reason, after assembly, as shown in FIG. 5 (B), gravity acts in the optical axis direction, so that the elastic support member 46 is bent, and the movable member 42 is moved along the axis P of the coil 43 and the axis of the permanent magnet 45. It moves down to the position where Q matches, and this position becomes the operation center. However, according to the "vertical type" apparatus as shown in FIG. 6B, it is not necessary to consider the bending of the elastic support member 42 due to the action of gravity, and the coil 43 of the movable member 42 is not required from the beginning.
The axis P of the fixed member 44 may be aligned with the axis Q of the permanent magnet 45 of the fixing member 44. For this reason, two types of mounting methods must be selected depending on the type, but this is not desirable because the production cost increases.

Further, as proposed in JP-A-59-221838, when the movable member and the fixed member are connected via the elastic support member, the center axis of the drive coil of the movable member and the permanent magnet of the fixed member are connected. If the movable member is lowered in the direction of gravity, for example, as in the case of a "horizontal type", a bias is applied by the weight of the movable member so that both central axes match. There is also a solution to
In this conventional example, when applied to a “vertical type” device, there is an advantage that there is no need to apply a bias,
In order to correct the amount of movement of the movable member due to its own weight when applied to a "horizontal type" device, the power consumption due to the bias current applied to the drive coil increases, and accordingly the amount of heat generated by the drive coil also increases. Disadvantage.

It is also conceivable to adjust the distance between the optical system support device and the optical information medium by changing the distance between the optical system support device and the optical information medium without passing a bias current through the drive coil. Therefore, there is a drawback that resonance occurs easily during operation, and the moving range of the movable member tends to be unstable.

An object of the present invention is to eliminate the above-mentioned disadvantages and to provide an optical system supporting device that does not deteriorate in performance and consumes less power even if the posture of the optical system supporting device during use is different.

[Means for Solving the Problems] The present invention, as exemplified in FIGS. 1 (A) and 1 (B),
A movable member (22) holding the optical system (21) is connected to a fixed member (36) through a plurality of elastic support members (23), and the movable member (22), Optical system (2
An optical system supporting device that drives at least the optical axis direction (L) and a direction orthogonal to the optical axis direction, wherein the optical axis direction (L) and the gravity direction (G) coincide with each other. In the first position, the movable member (22) is in the first position.
Of the optical system supporting device occupying the position (Q3) of the optical system, and the direction orthogonal to the optical axis direction (L) and the direction of gravity (G ') coincide with each other.
When the movable member (22) occupies the second position (Q1), the movable member (22) moves between the first position (Q3) and the second position (Q1). It is characterized in that the operation center is located.

[Action]

According to the present invention, for example, as shown in FIG.
The movable member 22 holding the optical system 21 and the fixed member 36 are positioned such that the axis P of the drive member (eg, drive coil) 25 of the movable member 22 is higher than the axis Q2 of the drive member (eg, permanent magnet) 32 of the fixed member 36. Then, the plurality of elastic support members 23 are connected to the movable member 22 and the fixed member 36 in a free state. At this time, the axis of the drive coil 25 occupies the position of Q1. Thus, the movable member 22 and the fixed member 36 are connected via the elastic support member 23.

After installation, for example, in the case of "horizontal type", the first
As shown in FIG. 7B, in a state where the movable member 22 is free, the movable member 22 is lowered to a position where the axis P of the drive coil 25 and the axis Q3 of the permanent magnet 32 coincide, and the elastic support member 23 is bent. State. Next, as shown in FIG. 1 (C),
Considering the weight of the movable member 22 and the elastic force of the elastic support member 23, a bias current is applied to the drive member (coil) 25 to lift the movable member 22 from the position Q3 to the position Q2. At this time, the elastic support member 23 is slightly bent, and the movable member 22 operates around a position where its axis P coincides with the position Q2 of the fixed member 36. That is, the position Q2 is the operation center position.

In the case of the "vertical mounting type", the movable member 22 is in the posture shown in FIG. 1 (A) in a free state. In consideration of the elastic force of the elastic support member 23 and the like, Flow the reverse bias current to the “horizontal type”, and move the axis P to the axis Q2.
Adjust to

With such an arrangement, even when the use posture of the optical system support device changes, the displacement of the movable member from the operation center position can be reduced, and therefore, the movable member is corrected to the operation center position. Therefore, the amount of bias current to the driving member can be reduced, so that power consumption is reduced and heat generation is reduced.

〔Example〕

2 to 4 are perspective views each showing the configuration of an embodiment of the optical system support device of the present invention. The objective lens 21 is a lens holder of a movable member 22 made of an integrally molded plastic body.
Fixed to 22A. In the present example, the objective lens 21 is formed of a plano-convex cell hook lens. The movable member 22 includes a rectangular frame 22B having a rectangular cross section so as to surround the lens holder 22A.
The lens holder 22A rises from the bottom wall 22c of the frame. Support portions 22D to 22G for supporting the linear elastic support members 23A to 23D are formed on the mutually facing side walls of the frame 22B. 2 to 4, one support portion 22G is not visible. As shown in FIG. 4, a print coil 24 is fixed to the outer peripheral surface of the frame 22B by bonding. In the developed view of FIG. 4, the printed coil 24 is one in which four tracking coil portions 24A to 24D are provided on a flexible insulating sheet, and two layers of coils are stacked on each coil portion via an insulating film. ing. These coils are electrically connected to each other, and both terminals are connected to lands 24E and 24F. In order to position the print coil 24 when attaching it to the outer peripheral surface of the frame 22B, the frame 22
A protrusion 22H is formed at the lower part of one side surface of B, and a recess 24G formed in the print coil 24 is fitted therein. A focusing coil 25 is further wound around the outside of the print coil 24. The terminal wires of the focusing coil 25 are connected to lands 24H and 24I provided on the print coil 24.
The movable member is configured in this manner, and the elastic support members 23A to 23A
Connect to the fixed member via 3D.

The fixing member 36 is a base 31 made of an integrally molded magnetic material.
It has. The base 31 has a bottom portion 31A, and integrally forms four yoke portions 31B to 31E rising vertically upward from the bottom portion 31A. Permanent magnets 32A and 32B are fixed to the inner surfaces of the yokes 31B and 31C. In this example, these yoke parts
Grooves 31F and 31G are formed on the inner surfaces of 31B and 31C, and permanent magnets 32A and 32B are yoke portions 31B and 31C by magnetic force.
Then, an adhesive is poured into the grooves 31F and 31G to fix the permanent magnet to the yoke. With such a configuration, the permanent magnet can be accurately positioned and fixed with respect to the yoke portion, and the assembling is facilitated, which is particularly suitable for automatic assembling by a machine.

An insulating plate 33 and a printed circuit board 34 are fixed to the outer surface of the yoke portion 31C of the base 31 of the fixing member 26 with screws 35. A pair of protrusions 33A and 33B are provided on the inner surface of the insulating plate 33, and the yoke 31C is fitted between these to determine the position. In addition, grooves 33C to 33F into which the ends of the elastic support members 23A to 23D fit are formed on both side surfaces of the insulating plate 33, and grooves 34A to 34D having the same dimensions are formed at positions corresponding to the side surfaces of the printed circuit board 34. I do. As is clearly shown in FIG. 3, a substantially ring-shaped ridge 31H is formed on the lower surface of the bottom 31A of the base 31, the tip surface thereof is curved, and the disk-shaped information medium is supported by supporting the objective lens driving device. To be rotatably mounted on a carriage driven in the radial direction. A part of the ridge 31H is cut out together with the base bottom 31A to form an optical path. Thus, the fixing member 36 is configured.

In connecting the movable member 22 and the fixed member 36 configured as described above via the elastic support member 23, FIG.
As shown in FIG. 2, the axis P of the drive coil 25 is attached to a position Q1 above the center axis Q2 of the permanent magnet 32 of the fixed member. In this case, if a bias current is not supplied to the drive (focusing) coil 25 in a posture in which gravity acts in the Z-axis direction, as shown in FIG. Deflects downward by the weight of the movable member 22 so that the reference axis P of the movable member 22 matches the axis Q3 of the permanent magnet 32 of the fixed member 36. Drive coil 25 and permanent magnet 32
Are positively or negatively applied to the drive coil 25 to displace the drive coil 25 by ▲ and ▼. In this way, the drive coil 25 and the print coil 24 are set to the positions where they face the permanent magnets 32A and 32B and the resonance of the movable member is minimized. In a posture where gravity acts in the Y-axis direction in FIG. 1 and no bias current is supplied to the drive coil 25, the elastic support member 23 does not bend as shown in FIG. , The movable member 22
Is aligned with the position Q1 of the fixing member 36. Also in this case, in order to directly face the drive coil 25 and the permanent magnet 32,
When a negative or positive bias current is applied to the drive coil 25,
Displace only by ▼. Therefore, in any case, the magnitude of the bias current to be supplied only needs to be corrected by an amount smaller than the maximum amount of movement Δ ▼ of the movable member 22 due to its own weight.

In this case, the stopper that regulates the moving range of the movable member 22 in the Z-axis direction (focus direction) is, in this case, a movable member.
It is preferable to set so that a desired movement amount (for example, ± 1 mm) can be secured on both the positive side and the negative side in the Z-axis direction with respect to 22. When the optical system supporting device is used in postures in three or more directions, it is necessary to set the position of each component according to the present invention in accordance with all the states and the frequencies.

Further, instead of using a metal wire as the elastic support member, a thin plate may be used, or a rubber-like elastic body may be integrally attached to the outer periphery of the metal wire.

〔The invention's effect〕

In the present invention, as shown in FIG. 6, even when the mounting posture of the optical system support device to the optical disk device or the like is different, the operation center of the optical system support device is changed by changing the bias current to the drive coil. Since the position can be made constant, that is, one type of optical system supporting device can be used, it is advantageous from the viewpoint of design and manufacturing, and it can be set to minimize the occurrence of resonance at the operation center position. Sufficient performance can be maintained.
Also, the positive or negative bias current for compensating the displacement of the movable member due to its own weight when the mounting posture of the optical system support device changes, because the correction distance is small,
It can be operated with less power consumption and less heat generation.

[Brief description of the drawings]

1A to 1C are conceptual diagrams showing the basic configuration of an optical system support device according to the present invention. FIGS. 2 to 4 are perspective views showing the configuration of an embodiment of the device according to the present invention. 6A and 6B are diagrams showing the configuration of a conventional optical system supporting device, and FIGS. 6A and 6B are diagrams showing the type of an optical disk device incorporating the optical system supporting device. 21 optical system 22, movable member 23 elastic support member 25 driving (focusing) coil 32 permanent magnet 36 fixed member L optical axis direction of optical system, G, G ' …… gravity direction

Claims (1)

(57) [Claims] A movable member holding an optical system is connected to a fixed member via a plurality of elastic support members, and the movable member, that is, the optical system is driven at least in a first direction by a driving member. In the optical system supporting device, in the first posture of the optical system supporting device in which the first direction and the direction of gravity acting on the movable member coincide with each other, the movable member is in the first position.
In the second posture of the optical system supporting device, wherein the second direction orthogonal to the first direction and the direction of gravity coincide with each other, when the movable member occupies the second position, First
An optical system supporting device, wherein the operating center of the movable member is located between the position (1) and the second position.