JPH08124192A - Objective lens supporting device - Google Patents

Abstract

PURPOSE: To attenuate the vibration of a lens driving supporting body in the radial direction and to suppress useless resonance by which the whole supporting body is vibrated. CONSTITUTION: A parallel link provided with a fixed plate 4, a lens holding body connection plate 5 opposite to the plate 4 and upper/lower horizontal plates 6, 7 each arranged across these both plates 4, 5, and formed by connecting these four sheets of plates so as to form a parallelogram with thin focusing hinges is constituted. Further, this device is provided with the lens driving supporting body 1 for connecting a lens holding body 2 to the lens holding body connection plate 5 through a thin tracking hinge H2. The focusing hinges adopt the hinges H13, H14 easily expandable and contractible and capable of absorbing vibration, and the vibration of the lens driving supporting body 1 in the radial direction is attenuated by the hinges.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup used in an optical information recording / reproducing device such as an optical disc player, and more particularly to an objective lens supporting device for the optical pickup.

[0002]

2. Description of the Related Art An optical pickup device of this kind is an optical disc which is formed by condensing a light beam emitted from a light beam generating means such as a semiconductor laser on a recording surface of the optical disc as a condensing spot having a predetermined diameter by an objective lens. The recording and erasing of signals from the optical disc and the detection of signals from the optical disc are performed.

Therefore, in order to perform these operations with high accuracy, the distance between the objective lens and the recording surface of the optical disk is affected by the irregularities on the recording surface of the optical disk, the accuracy of the spindle mechanism on which the optical disk is mounted, and the like. Without
It is necessary to always keep it constant, and it is necessary to prevent the above-mentioned focused spot from being displaced from the recording track on the recording surface of the optical disc. Therefore, in the optical pickup device, the objective lens is arranged in the direction of the optical axis (focusing direction) and the direction orthogonal to this direction (tracking direction).
And an objective lens supporting device for movably supporting the lens.

An example of this type of objective lens support device is shown in FIG.
Shown in In FIG. 2, the objective lens support device is mainly composed of a lens driving support 1, a lens holder 2 and a base 3.

The lens driving support 1 is, for example, an integrally molded product of soft synthetic resin, and has a fixing plate 4 fixed on the base 3, a lens holding member connecting plate 5 facing the fixing plate 4, and both plates 4 thereof. , 5 has an upper horizontal plate 6 and a lower horizontal plate 7 each having a trapezoidal vertical cross section, and these plates 4 to 7 are connected by a thin focusing hinge H1 so as to form a parallelogram. As a result, a parallel link is formed, and the plate-shaped rotating portion 8 is connected to the surface of the lens holder connecting plate 5 facing the fixed plate 4 with the tracking hinge H2.

A lens driving support 1 having such a structure
Is a pair of bosses 9 and 9 projecting from the lower surface of the fixing plate 4, fitted into the fixing holes 10 and 10 of the base 3, and a fixing shaft 11 protruding from the upper surface of the base 4. It is fixed on the base 3 by being inserted into the shaft hole 12 of No. 4.

The lens holder 2 has an objective lens 1 on the front upper surface.
3, the objective lens 13 is provided with a focus coil 14 for moving the objective lens 13 in the focus direction (arrow Y direction) and a tracking coil 15 for moving the objective lens 13 in the tracking direction (arrow X direction). An opening 16 is formed in a region from the rear to the rear end of the lens driving support 1 including the lens drive support 1 and having a size in consideration of the deformation of the support 1. The lens holder 2 is attached to the lens driving support 1 by fitting the grooves 17 on both side surfaces of the opening 16 into both ends of the rotating portion 8 of the lens driving support 1. It is coupled and is displaced in the focusing direction by the deformation of the parallel link by the focusing hinge H1 of the lens driving support 1, and in the tracking direction by the swinging of the rotating portion 8 by the tracking hinge H2.
The focus and tracking coils 14 and 15 are electrically connected to an external circuit board (not shown) by a flexible wiring board 18.

The base 3 has a pair of yoke plates 1 on both left and right sides.
The magnets 9 and 20 are erected on the inside and the outside so as to be separated from each other as appropriate, and a plate-shaped magnet 21 is provided on the inner surface of the outer yoke plate 19. Focusing and tracking coils 14 and 15 are arranged in the magnetic gap between 21.

Thus, in the objective lens supporting device having the above structure, when a current is passed through the focus coil 14, a driving force in the direction of the arrow Y corresponding to the direction of the current is generated, and the fixed plate 4 and the lens holder are connected. The lens holder 2 or the objective lens 13 is displaced in the focus direction due to the deformation of the parallel link composed of the plate 5, the upper horizontal plate 6 and the lower horizontal plate 7, and a current is passed through the tracking coil 15 in accordance with the direction of the current. A driving force in the direction of arrow X is generated, and the lens holder 2 or the objective lens 13 is displaced in the tracking direction by the swinging of the rotating portion 8.

By the way, in such an objective lens supporting device, as shown in FIG. 3, the focusing hinge H11 is conventionally different from the fixing plate 4, the lens holder connecting plate 5, and the upper and lower lateral plates 6 and 7. It was thin and had a rectangular cross section, and was formed linearly in the connecting direction of each plate.

[0011]

Since the lens-driving support in the objective-lens support device having the above-described structure is composed exclusively of a soft synthetic resin molding, the focusing hinge H11 having the shape shown in FIG. Even if there is, expansion and contraction cannot be avoided, and especially when the lens holding body 2 is driven in the tracking direction by swinging of the rotating portion 8 about the tracking hinge H2 as a fulcrum, the lens drive is caused by expansion and contraction of the focusing hinge H11. The support 1 for vibration vibrates in the radial direction, and an unnecessary resonance occurs in which the entire support for driving the lens vibrates. This resonance adversely affects the displacement of the lens holder 2 and also adversely affects the information reading performance. It wasn't there.

However, according to the present invention, the vibration of the lens driving support in the radial direction is attenuated to suppress unnecessary resonance of the entire support.

[0013]

SUMMARY OF THE INVENTION The present invention has been made for the purpose of solving the above problems, and in the objective lens supporting device according to claim 1, a fixing plate, a lens holding member connecting plate facing the fixing plate, and 2 straddled between these two boards
A parallel link is formed by having four plates and connecting these four plates with a thin focus hinge to form a parallelogram, and a thin tracking hinge on the lens holder connecting plate. In the objective lens supporting device, the objective lens supporting device is provided with a lens driving support member that connects a lens holding member via a lens, and the fixing plate is fixed to a base so that the objective lens can be moved in the focus and tracking directions. Is formed into a shape that can easily expand and contract and absorb vibration.

Further, in the objective lens supporting device described in claim 2, in the objective lens supporting device described in claim 1, the focusing hinge is curved in an arc shape in the connecting direction of the plates.

[0015]

According to the above construction, the radial vibration of the lens driving support can be absorbed, that is, attenuated by the focusing hinge, and the entire lens driving support when the lens holder is driven in the tracking direction. It is possible to suppress unnecessary resonance such as vibration of.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiment of the present invention shown in FIG. 1 will be described in detail below with reference to FIG. FIG. 1 is an enlarged perspective view showing a main part of an objective lens supporting device according to an embodiment of the present invention, in which (a) and (b) show different examples.

The objective lens supporting device according to this embodiment has basically the same structure as the objective lens supporting device shown in FIG. 2, and is different from FIG. 2 only in the shape of the focusing hinge. Therefore, in FIG. 1, the same parts as those in FIG. 2 are designated by the same reference numerals.

In the objective lens supporting apparatus according to the present embodiment, the focusing hinge H13 has a shape that allows easy expansion and contraction, for example, a curved shape in an arc shape, and as shown in FIG. The holding body connecting plate 5 is connected to the holding body connecting plate 5 by a focusing hinge H13 which is curved upward in an arc shape,
Further, as shown in FIG. 1B, the upper horizontal plate 6 and the lens holder connecting plate 5 are connected by a focusing hinge H14 which is curved outward in an arc shape.

In FIG. 1, only the connecting portion between the lens holder connecting plate 5 and the upper horizontal plate 6 is shown, but the upper horizontal plate 6 and the fixing plate 4, the lens holding member connecting plate 5 and the lower horizontal plate are also shown. A structure in which the plate 7, the fixed plate 4, and the lens holder connecting plate 5 are connected at two positions on the left and right by a hinge H13 or H14 for focusing, respectively, is employed. It is composed of a synthetic resin integrally molded product.

In this embodiment, by adopting the above-mentioned structure, the vibration of the lens driving support 1 in the radial direction can be absorbed or attenuated by the shape of the focusing hinges H13 and H14. It is possible to suppress unnecessary resonance in which the entire lens driving support 1 vibrates during the driving in the tracking direction 2.

The focus hinge is not limited to the shape shown in the above embodiment, but may be any shape as long as it can easily expand and contract and absorb vibrations as compared with the conventional linear hinge. However, the lens driving support needs to have a shape in which the parallel link that deforms when driven in the focus direction does not break the parallelogram.

[0022]

As described above, according to the objective lens supporting device of the present invention, the vibration of the lens driving support in the radial direction can be absorbed by the shape of the focusing hinge, so that the entire lens driving support can be provided. Unwanted resonance that vibrates can be suppressed, and good information reading performance can be provided.

[Brief description of drawings]

FIG. 1 is an enlarged perspective view showing a main part of an objective lens supporting device according to an embodiment of the present invention, in which (a) and (b) show different examples of a focus hinge.

FIG. 2 is an exploded perspective view showing a general objective lens supporting device.

FIG. 3 is a diagram for explaining a focusing hinge in a conventional objective lens supporting device.

[Explanation of symbols]

 1 Lens driving support 2 Lens holder 3 Base 4 Fixing plate 5 Lens holder connecting plate 6 Upper horizontal plate 7 Lower horizontal plate 8 Rotating part 13 Objective lens 14 Focus coil 15 Tracking coil H1, H13, H14 For focus Hinge H2 Tracking hinge

Claims (2)

[Claims] 1. A fixed plate, a lens holding member connecting plate facing the fixed plate, and two plates arranged so as to straddle the two plates, and these four plates are parallel to each other with a thin focus hinge. A parallel link is formed by connecting so as to form a quadrangle, and a lens driving support for connecting the lens holding body to the lens holding body connecting plate via a thin tracking hinge is provided on the fixing plate. In an objective lens supporting device in which an objective lens is fixed to a base so that the objective lens can be moved in the focus and tracking directions, the focusing hinge is formed in a shape that allows easy expansion and contraction and vibration absorption. . 2. The objective lens supporting device according to claim 1, wherein the focusing hinge is curved in an arc shape in the plate connecting direction.