JPS62295230A - Lens holding device - Google Patents

Abstract

PURPOSE:To obtain a lens holding device that can be moved softly and smoothly in the direction of the optical axis of a lens maintaining the optical axis of the lens and has sufficient rigidity in nearly radial direction of a disk by bending at least one or more of plural leaf springs in the direction of the optical axis of the lens in a single free state. CONSTITUTION:A lens 11 that forms an image on a disk 12 is fixed to a holder 13. The holder 13 has two planes 13a, 13b that intersect the optical axis of the lens 11 at nearly right angles, and leaf springs 14a-14d are fixed on them. Other ends of leaf springs 14a-14d are fixed to two planes 15a, 15b that intersect at nearly right angles to the optical axis of the lens 11 on a shifting stand 15 provided movably in nearly radial direction (direction of the arrow mark X) of the disk 12. Thereby, force that is apt to generate local and minute creases when attaching plural leaf springs between the holder and shifting stand is absorbed by a bent part in the direction of optical axis of the lens possessed by the single leaf spring in the free state.

Description

Detailed Description of the Invention 3. 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, in compact disc players and optical disc devices, there has been a movement to support objective lenses with leaf springs in order to improve reliability and ease of assembly.

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

FIG. 4 is a top view of a conventional lens support device, and FIG. 5 is a sectional view of FIG. 4 viewed from the side. 1 is a lens that forms an image on the disk 2 and is fixed to the holder 3. The holder 3 has two surfaces 3a, 3 that are substantially perpendicular to the optical axis of the lens 10.
b, to which leaf springs 4a to 4d are fixed. The other ends of the leaf springs 4a to 4d are attached to a transfer table 5 which is movable in the approximately radial direction of the disk 2 (in the direction of the arrow px force).
A to 4C are fixed so that they are substantially parallel. An optical bench 6 supplies light emitted from a semiconductor laser or the like to the lens 1 through various lens threads, and is usually fixed to the transfer table 6.

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 warpage, in the direction of arrow Y.

Since various methods have been disclosed in the past regarding means for causing tracking and means for detecting tracking error, their description will be omitted here.

Similarly, the lens 1 must be able to move in the direction of the arrow X and follow any desired track in order to follow the track provided on the disk 2 or scan any desired track. Since various known means can be applied to the detection means, the description thereof 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 Y, lens 1
It is necessary for the leaf springs 4a to 4d to deform so as to move softly and smoothly while maintaining the optical axis. Next, the transfer table 6 is suddenly applied in the direction of arrow X.

It is desirable that the optical axis of the lens 1 does not undergo vibrational displacement due to deceleration. From the above, the thickness of the leaf springs 4a to 4d is usually 10
Manufactured from a thin metal plate with a thickness of μm to 50μm, and the shape is also 4a to 50μm.
In many cases, all 4d had the same shape.

Problems to be Solved by the Invention However, in the above configuration, the plate springs 4a to 4d are thin and have very low rigidity in the direction of arrow Y, so it is difficult to attach the plate springs 4a to 4d to the holder 3 or the transfer table 5. When tightening, it is common for the leaf spring 4a, for example, to wrinkle locally and minutely, as shown in FIG. There are various reasons for this, but one simple reason is that when the leaf springs 4a to 4d are installed between the holder 1 and the transfer table 6, the leaf spring 4a is slackened by only 6 to 10 μm relative to the leaf springs 4b to 4C. It occurs just by fixing it. From the state shown in FIG. 6, point the lens 1 with the arrow Y.
When a displacing force is applied in the direction of the disk 2, a phenomenon occurs in which the wrinkles that have appeared on the leaf spring 4a at a certain position instantaneously disappear, and the displacement of the lens 1 also instantaneously increases. On the other hand, when the lens 1 is returned to its initial direction from this state, a phenomenon occurs in which the leaf spring 4a instantly wrinkles at a certain position and the displacement of the lens 1 suddenly decreases. This situation is shown in FIG. These phenomena indicate that there is a range in which the lens 1 cannot follow the disc 2, and specifically, it becomes a serious drawback that signals recorded on the disc 2 cannot be read in the range where this phenomenon occurs.

On the other hand, when the transfer table 6 rapidly accelerates or decelerates in the direction of the arrow X shown in FIG. 4, inertia of the lens 1 and holder 3 is generated.
When this force is equally received by the leaf springs 4a to 4d, the lens 1
There is no displacement in the direction of arrow X, and no tilting of the optical axis occurs.

However, as shown in FIG. 6, if local minute wrinkles occur in the leaf spring 4a, for example, the leaf spring 4b
Since the rigidity in the direction of the arrow X of ~4d' is different, when the inertial force is generated, the lens 1 may be displaced or vibrated in the direction of the arrow X.
The optical axis of the lens 1 vibrates. This vibration and displacement is caused by the transfer table 6
This not only deteriorates the followability when following an arbitrary track, but also causes serious drawbacks such as making it impossible to follow the track and recording the contents on the disk 2, making it impossible to read the contents.

In view of the above problems, the present invention has been developed by configuring the leaf springs 4a to 4d that support the lens 1 so that they can be easily attached to the holder 3 and the transfer table 5 without causing local and minute wrinkles. The optical axis of the lens 1 can be displaced softly and smoothly in the direction of the arrow Y while maintaining the optical axis of the lens 1, and the optical axis of the lens 1 can be displaced in response to rapid acceleration/deceleration of the transfer table 5 in the direction of the arrow X.
A vibration-free lens support device is provided.

Means for Solving 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 a lens fixed to two surfaces of the holder that are substantially orthogonal to the optical axis of the lens. a plurality of leaf springs, the other ends of which are fixed to two surfaces substantially orthogonal to the optical axis of the lens, and at least one of the plurality of leaf springs is is curved in the optical axis direction of the lens when it is in a free state.

Effect The present invention has the above-described configuration, so that when a plurality of leaf springs are attached between a holder and a transfer table, the force that tends to cause local minute wrinkles can be absorbed by the lens optical axis, where each leaf spring has a free state. The purpose is to absorb it at the curved portion in the direction, that is, to release it as a difference in the amount of curvature, and thereby eliminates various serious defects caused by localized and minute wrinkles that conventionally occur in leaf springs.

EXAMPLE Hereinafter, a lens support device according to an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a top view of the first embodiment of the present invention, and a top view of the second embodiment of the present invention.
This figure is a cross-sectional view of FIG. 1 seen from the side, and FIG. 3 shows the shape of the single leaf spring used in the first embodiment in its free state. Reference numeral 11 denotes a lens that forms an image on the disk 12 and is fixed to the holder 13. The holder 13 has two surfaces 13a and 13b that are substantially perpendicular to the optical axis of the lens 11, and plate springs 14a to 14d are fixed thereto. Leaf spring 14a~
The other end of 14d is two surfaces 15a that are on a transfer table 15 that is movable in the approximately radial direction of the disk 12 (in the direction of the arrow X) and that are approximately orthogonal to the optical axis of the lens 11.

15b. Note that an optical bench 16 supplies light emitted from a semiconductor laser or the like to the lens 11 through various prisms, etc., and is usually fixed to the transfer table 16.

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. Here, leaf springs 148 to 14d
It will be explained why local and minute wrinkles do not occur by making the shape in the free state as shown in Fig. 3. Also in this configuration, among the leaf springs 14a to 14d, for example, 14a
When the paper is fixed between the holder 13 and the transfer table 15 with a slight slack relative to the paper 14b to 14d, a force that causes wrinkles is generated. However, since the curved portions of the leaf springs 14a to 14biC are provided in advance, the force that causes this wrinkle is substantially the difference between the curved heights of the plate springs 14a and 14b to 14d, and local minute wrinkles do not occur. This phenomenon is thought to be caused by the same reason as the small wrinkles on the plate spring 4a shown in the conventional example, which instantly disappear when absorbed by the large curvature of the plate spring 4a caused by the displacement of the lens 1.

In other words, the present invention takes the state where the wrinkles of the conventional example have disappeared as a stable point, and curves the leaf springs 14a to 14d in advance so that wrinkles do not occur within the movement range of the lens 11 in the Y direction.
It is thought that it was set up in

As described above, according to this embodiment, the leaf springs 14a to 14d
By giving Vc a curve in advance and fixing it to the holder 13 and the transfer table 15, the force that would normally cause localized and minute wrinkles can be absorbed by the large curved portion provided in advance in the plate springs 14a to 14diC. This means that leaf spring 14
This shows that the characteristics required for a to 14d can be easily obtained even during mass production.

In this embodiment, all of the leaf springs 14a to 14d are provided with large curvatures, but modifications can be made, such as providing them only on the leaf springs 14a and 14b and using conventional shapes for the leaf springs 14C and 14d. The effect at this time will be halved. Further, in this embodiment, the leaf springs 14a to 14d are provided separately and independently, but each of the leaf springs 14a, 14b, 114C, and 14d may be composed of a single leaf spring. Note that the leaf spring 14a~
The curved direction and shape of 14d can also be changed arbitrarily. Further, although the transfer table 15 is illustrated as moving straight in the direction of the arrow X, the present invention is not limited to this.

Effects of the Invention As described above, the present invention provides a lens, a holder for holding the lens, a plurality of leaf springs fixed to two surfaces of the holder substantially orthogonal to the optical axis of the lens, and a plurality of leaf springs. a transfer table having the other end of a spring fixed to two surfaces substantially orthogonal to the optical axis of the lens, and bending at least one of the plurality of leaf springs in a free state in the direction of the optical axis of the lens. Accordingly, it is possible to obtain a lens support device that can be softly and smoothly displaced in the direction of the lens optical axis while maintaining the lens optical axis, and has sufficient rigidity in the substantially radial direction of the disk.

[Brief explanation of drawings]

FIG. 1 is a top view of the lens support device in the first embodiment of the present invention, FIG. 2 is a sectional view of FIG. 1 when viewed from the side,
3 is a perspective view of the plate spring used in the first embodiment in a free state, FIG. 4 is a top view of a conventional lens support device, and FIG. 6 is a sectional view of FIG. 4 when viewed from the side. Figure 6 is a cross-sectional view showing a state where local and minute wrinkles have occurred in the leaf spring.The seventh factor is the relationship between the displacement force and the amount of lens displacement when applying a displacement force in the disk direction from the state in Figure 6. This is a graph showing. 1.11...Lens, 2.12...Disc, 3.13 Old...Holder, 4a to 4d, 1
4a to 14d... leaf spring, 5, 16...
...transfer table, 6,16...optical table. Name of agent: Patent attorney Toshio Nakao (1st person)
Figure 2, Figure 3

Claims (1)

[Claims] a lens, a holder that holds the lens, a plurality of leaf springs fixed to two surfaces of the holder that are substantially perpendicular to the lens optical axis, and the other end of the plurality of leaf springs is substantially perpendicular to the lens optical axis. A lens support device comprising a transfer table fixed to two orthogonal surfaces, wherein at least one of the plurality of leaf springs is individually free and curved in the optical axis direction of the lens.