JPS59195340A - Optical pickup supporter - Google Patents

Abstract

PURPOSE:To obtain an inexpensive optical pickup with light weight by connecting orthogonally two pairs of plate springs set in parallel to each other, and fixing an end of the plate spring rectangularly to a lens holder, and fixing the other end orthogonally to a main body supporting member of the optical pickup. CONSTITUTION:When an objective lens 1 is shifted toward the optical axis, the 2nd plate springs 4 and 4' are kept as they are without change. While the 1st plate springs 3 and 3' are kept in parallel and at the same time have displacements with vertual fulcrums a-a' and c-c' with the spring 3 and fulcrums b-b' and d-d' with the spring 3' respectively. In this case, both springs 3 and 3' have the same degree of displacement although they are folded with each other since the corresponding plate springs have an equal length. Furthermore these springs function to each other so as to maintain a quadrilateral at all times in a side view. As a result, the optical axis has not tilt although the lens 1 is shifted toward an arrow B1-B2. Thus it is always possible to keep the optical axis vertical to a recording pit.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a support device for an optical pickup device that optically reads information.

Conventional Structure and Problems In order to reproduce the recorded pits of an information medium, it is necessary to correctly focus the light onto the recorded pits, and for this purpose, it is necessary to perform focal position control and track tracking control. In conventional focal position control, the objective lens is supported by a spring that can move only in the optical axis direction. Furthermore, tracking servo that follows track changes in the radial direction of recording pits has been performed by swinging the optical axis in the tracking direction using a galvanometer or the like placed in the middle of the optical system. In such an optical system, the light beam during the tracking operation may pass obliquely to the optical axis of the objective lens, and in this case, it becomes difficult to remove the aberration of the objective lens. There was a contradiction in that the number of lens components increased, the weight increased, and the servo characteristics also deteriorated. There was still a drawback that it was difficult to miniaturize the optical system and the optical recording/reproducing device itself became large.

OBJECTS OF THE INVENTION The present invention was made in order to eliminate the above-mentioned drawbacks of the prior art, and it is an object of the present invention to provide a lightweight and inexpensive support mechanism for an optical pickup.

Structure of the Invention The present invention provides a pair of plate springs arranged parallel to each other for a recording medium, a pair of plate springs arranged perpendicularly to each other, a surface element connecting the two,
This is an optical pickup support device equipped with an optical pickup main body support member, and while the optical axis of the objective lens is always placed perpendicular to the recording focus, the objective lens is aligned in the optical axis direction (focus direction) and in the direction perpendicular to the optical axis (tracking direction). ) can be moved arbitrarily. In other words, the focus control mechanism and the track tracking control mechanism can be integrated, and as a result, the aberration of the objective lens can be easily eliminated, the optical configuration can be simplified, and the device can be made smaller and lighter, making it cheaper overall. can.

Description of examples FIG. 1 is a perspective view of a first embodiment of the invention.

In Figure 1, 1 is an objective lens, 2 is a lens holder, 3 and 3' are the first two parallel plate springs arranged parallel to the surface of the recording medium, and 4 and 4' are perpendicular to the surface of the dispensing medium. The second parallel arrangement of leaf springs arranged in
One end of the first leaf spring 3' is fixed at right angles, and one end of the second leaf spring 4,4' is attached to the first leaf spring 3,
A large rigid surface element 6 is connected at a right angle at a position offset by 900 degrees from 3', and 6 is a main body support member of the optical pickup, which is attached to the main body base.

The operation of the first embodiment configured as described above will be explained below with reference to FIGS. 2 and 3. First, FIG. 2 is a side view showing the objective lens when viewed from the entrance direction of FIG. 1. 1 shows the movement of the objective lens 1 in the optical axis direction, that is, the movement of the objective lens 1 during focus servo.

Now, when the objective lens 1 is moved in the optical axis direction as shown in Fig. 2, the second leaf springs 4 and 4' remain unchanged, and the first leaf springs 3 and 3' are parallel to each other. While maintaining , a-a', C-C' for leaf spring 3.

The leaf spring 3' is deformed using bb' and dd' as temporary fulcrums. In the case of , the lengths of the corresponding plates are the same, so even if plates 3 and 3' are bent together, the amount of displacement is the same, and in the side view they always look like parallelograms. They work together to maintain the shape. Therefore, even if the objective lens 1 is moved in the direction of arrows B1-B2, the optical axis does not tilt, and it is possible to always keep the optical axis perpendicular to the recording focus. .

FIG. 3 is a top view showing the movement of the objective lens 1 in the direction perpendicular to the optical axis when viewed from direction B in FIG. 1, that is, the movement of the objective lens 1 during tracking servo.

Now, when the objective lens 1 is moved in the direction perpendicular to the optical axis as shown in FIG. While keeping parallel, leaf spring 4 is hh-h'.

(J-q' and leaf spring 4' are displaced using f-f' and e7e' as temporary fulcrums, respectively. In this case as well, the corresponding leaf springs 4 and 4' are displaced in the same way as explained in Fig. 2. Since they have the same length, even if they are bent, the amount of displacement is the same, and they always work together to maintain a parallelogram in top view. Even when the leaf springs 3, 3' and 4, 4' are bent, the optical axis does not shift, and the optical axis can always be kept perpendicular to the recording pit. Since it is fixed at a right angle, the fixed part flexes while maintaining the right angle state, so that the shape of the deflection when viewed from directions A and B in Figure 1 becomes S-shaped, but as explained above, No problem arises because the corresponding leaf springs are displaced in the same way.

As described above, according to this embodiment, the objective lens can be fixed to the objective lens using a simple structure in which two pairs of parallel-arranged leaf springs are orthogonally connected to each other, and one end is fixed to the lens holder and the other end is fixed to the optical pickup main body support member. It can be moved to any position in the direction of the optical axis and in the direction perpendicular to the optical axis without tilting the optical axis.In particular, the torsional strength against the optical axis is high, which is not found in conventional optical pink-up support mechanisms. can get.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a perspective view of a second embodiment in which the main body support member 6 of the optical pink-up is arranged close to the objective lens 1 in consideration of miniaturization. The features are:
The plate springs 41 and 41' are arranged 180 degrees opposite to the plate springs 4.4' in FIG. 1, and the basic operation is no different. Since the plate springs 31.31' and 41.41' are close to each other, it is necessary to form a relief part in consideration of the amount of displacement of the objective lens 1 so that they do not come into contact with each other.

In this case, in FIG. 4, the shape of the leaf spring is trapezoidal. As described above, the second embodiment has the feature that it can be configured more compactly than the first embodiment.

Next, a third embodiment in which the support device according to the second embodiment is used to actually drive the objective lens will be briefly described with reference to FIG. In the same figure, 7
and 7' are independently wound coils, and 8 is a permanent magnet, which are arranged at positions corresponding to the coils 7 and 7'. 9 is a yoke that constitutes a magnetic circuit, and 1o is a dome core around which a coil 7.7' is wound, which is directly connected to the lens holder 2.

The operation of the third embodiment configured as described above will be described below. Now, independently wound coils 7 and 7'
When a current is passed through, a magnetic field is formed by the yoke 9 which forms a magnetic circuit together with the permanent magnet 8 placed correspondingly, so according to Fleming's left hand rule, the lens holder Core 1 directly connected to 2
Force acts on 0. At this time, since the coils 7 and 7' are tilted at 45 degrees and perpendicular to each other with respect to the optical axis of the objective lens 1, the magnitude of the current supplied to the coils 7 and 7' causes the The objective lens 1 can be directly moved to any position on a plane parallel to the optical axis. That is, by controlling the magnitude of the current applied to the coils 7 and 7', focus control and track tracking control of the objective lens 1 becomes possible.

At this time, the optical axis of the objective 1/lens 1 is always held perpendicular to the recording pit, as described above.

As described above, according to the third embodiment, it is possible to realize an optical pickup driving device using the second embodiment, and it has a large torsional strength with respect to the optical axis that conventional optical pickups do not have, and also has a This makes it possible to downsize as the number decreases.

It goes without saying that in the first to third embodiments, the optimum spring constant can be obtained by selecting the shape or thickness of the leaf spring. Still, the first leaf spring 3, 3'
The surface element 5 connecting the and second leaf springs 4, 4' may be omitted and an integrated leaf spring may be used.

Effects of the Invention The present invention is a simple method in which two pairs of parallel plate springs are connected at right angles to each other, one end is fixed at right angles to the lens holder, and the other end is fixed at right angles to the optical pinocap main body support member. By adding a driving part to this support device, the optical axis of the objective lens will not be tilted.
The objective lens can be moved to any position in the optical axis direction and in the direction perpendicular to the optical axis. In other words, the focus control mechanism and the track tracking mechanism can be integrated, and since the optical axis of the objective lens always moves while being held perpendicular to the recording pit, it is necessary to eliminate comatic aberration of the objective lens, and optical The configuration can be simplified, and a lightweight and inexpensive optical pickup can be realized. In particular, the torsional strength of the objective lens with respect to the optical axis can provide excellent characteristics not found in conventional optical pink-up support devices of this type.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the first embodiment of the present invention, FIG. 2 is a side view as seen from the entry direction in FIG. 1, and FIG. 3 is a top view as seen from direction B in FIG. 1. , FIG. 4 is a perspective view of the second embodiment, and FIG. 6 is a trunk view of a third embodiment using the support device according to the second embodiment. 1... Objective lens, 2... 1/lens holder, 3°3', 4.4'... Leaf spring, 5...
... Plate joint connecting surface element, 6.6' ... Optical pickup main body support member, 7,7' ... Coil, 8
...Permanent magnet, 9...Yoke, 10...
...Core 0 Name of agent Patent attorney Toshio Nakao and 1 other person 1st
Figure B direction 6 8 Figure 4 t' Figure 5

Claims (1)

[Claims] A first pair of parallel rectangular plate springs of equal size arranged parallel to the optical recording medium surface, and a second pair of parallel rectangular plates arranged perpendicular to the recording medium plane of equal size. a spring, a pair of first leaf springs and a second leaf spring;
A surface element in which one end of a pair of leaf springs is orthogonally connected to each other, a lens holder fixed at right angles to the other end of the first pair of leaf springs, and the other end of the second pair of leaf springs. An optical pickup support device 0 characterized by comprising: an optical pickup main body support member fixed at right angles to the optical pickup main body support member;