JPS62231433A - Optical pickup - Google Patents

Abstract

PURPOSE:To obtain an optical pickup with high performance against external disturbance by inserting a viscoelastic member between an optical base and an actuator so as to be immune to the effect of vibration between the actuator and the optical base. CONSTITUTION:The viscoelastic member 7 is fitted between the actuator 2 and the optical base 3. Screw 61-64 are screws for adjusting the tilt of an objective lens and in turning the screws, the tilt of the objective lens 1 to an information medium 8 is adjusted by the elastic deformation of the viscoelastic member 7, Coil springs 41-44 act also like adjusting the tilt of the objective lens 1, but since the coil springs are used as a helper to the viscoelastic member 7, there is no limitation of spring constant and size. Thus, the shape of the coil springs provide no limitation to the miniaturization and thin profile of the optical pickup. As a material of the viscoelastic member 7, a synthetic rubber or the like is suited but other materials with excellent temperature, wear resistance and anti-compression distortion are used.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an optical pickup, and more particularly to an optical pickup used in a device that records or reproduces information by forming a light spot on an information carrier such as an optical disk.

(Prior Art) In general, in the above-mentioned recording or reproducing apparatus, in order to accurately read the information on the information carrier, the optical axis of the objective lens of the optical pickup must be perpendicular to the information carrier surface. If the objective lens is mounted at an angle to the information carrier surface, the light spot may not be narrowed down sufficiently on the information carrier surface, and due to the effects of astigmatism, etc., the performance of the objective lens may not be maximized. I can't. Therefore, a mechanism is required to adjust the inclination of the objective lens with respect to the information carrier surface. The tilt adjustment of the objective lens of a conventional optical pickup will be explained below.

FIG. 3 shows a conventional optical pickup, in which 1 is an objective lens, 2 is an actuator that drives the objective lens in the focus direction and the track direction with respect to the disk surface, 3 is an optical base, and 41, 42° and 43.44 are the aforementioned Coil springs 51, 52, and 53 inserted between the actuator 2 and the optical base 3 to hold the actuator 2; 54 are screw holes provided at the bottom of the actuator 2; 61.
Numerals 62, 63, and 64 are screws that are screwed into the screw holes 51, 52, 53, and 54, and compress the coil springs 41, 42, 43, and 44.

In this conventional configuration, in FIG. 3, four wooden screws 61,
When turning 62, 63, and 64 at any time, the coil springs 41, 42,
43 and 44 push up the actuator 2, and the tilt of the objective lens 1 is adjusted by the difference in the amount of push up.

However, when attempting to adjust the inclination of the objective lens using only the tension of the coil spring, the size, shape, and performance of the optical pickup device itself may be restricted by selecting the spring constant of the coil spring. Generally, optical pickups are small.

Thinness and high performance are required, but in the above configuration, for example, if the spring constant of the coil spring is made too small,
When the force holding the actuator 2 becomes smaller and disturbances such as vibrations and impact windows occur in the optical pickup, the coil spring tends to resonate, and the actuator becomes more susceptible to vibrations. In addition, if the length and diameter of the coil spring are adjusted to increase the spring constant so as not to be affected by vibration, the shape of the coil spring becomes larger, making it impossible to make the entire optical pickup smaller and thinner. There were some problems.

(Summary of the Invention) An object of the present invention is to solve the problems of the prior art described above and to provide an optical pickup in which the influence of vibration can be effectively reduced without increasing the size of the entire structure.

The above object of the present invention is achieved by interposing a viscoelastic body between the actuator and the optical base in an optical pickup in which an actuator for driving an objective lens is attached to an optical base so that its attachment angle can be adjusted. .

That is, in the present invention, since the actuator is attached to the optical base via the viscoelastic body, even if there is a disturbance such as vibration or impact on either the actuator or the optical base, this is absorbed by the viscoelastic body. , do not overshadow each other.

Furthermore, since the actuator adjusts the tilt of the objective lens through the elastic deformation of the viscoelastic body, by selecting the material and hardness of the viscoelastic body appropriately, even a relatively small viscoelastic body can have a wide adjustment range and tilt efficiently and quickly. Adjustments can be made.

Therefore, the shape and size of the optical pickup is not limited by the size of the viscoelastic body, and the optical pickup can be made smaller and thinner.

(Example) Embodiments of the present invention will be described in detail below with reference to the drawings.

1 and 2 show an embodiment of the optical pickup of the present invention, with FIG. 1 being an exploded perspective view and FIG. 2 being a schematic sectional view, respectively. In FIGS. 1 and 2, the same members as in FIG. 3 are given the same reference numerals. Here, 1 is the objective lens, 2
is actuator, 3 is optical base, 41, 42.43
゜44 is a coil spring, 51.52, 53.54 are screw holes, 61, 62.63.64 are screws, 7 is a ring-shaped viscoelastic body installed between the actuator 2 and the optical base 3, 8 is a It is an information carrier such as an optical disk.

In the above configuration, the screws 61, 62, 63, and 64 are screws for adjusting the inclination of the objective lens, and by turning the screws, the inclination of the objective lens 1 with respect to the information carrier 8 is adjusted by elastic deformation of the viscoelastic body 7. Here, the coil springs 41, 4
2, 43, and 44 also have the function of adjusting the inclination of the objective lens 1, but since the coil springs work as an aid to the viscoelastic body 7, they are not subject to restrictions such as spring constant and magnitude. Therefore, the shape of the coil spring does not make it impossible to make the optical pickup smaller and thinner.

Synthetic rubber or the like is preferably used as the material for the viscoelastic body 7, but other materials may be used as long as they have good temperature characteristics, wear resistance, and compressive strain resistance.

In this embodiment, this viscoelastic body 7 is formed into a ring shape and is arranged rotationally symmetrically with respect to the optical axis of the objective lens, so that elastic force is applied to the actuator 2 in a well-balanced manner, and the precise optical axis can be adjusted. This is particularly effective for adjusting the inclination of Further, the hole inside the viscoelastic body 7 is used to secure the optical path of the light beam incident on the objective lens 1.

The present invention is not limited to the first embodiment described above, and various modifications are possible. For example, in the embodiment, coil springs 41, 42°, 43.44 were also used to adjust the inclination of the objective lens 1, but these are auxiliary and may be omitted. Further, although the viscoelastic body 7 is fixed on the optical base 3 in the embodiment, it may be fixed on the bottom of the actuator 2.

That is, it only needs to be fixed to either one between the actuator and the optical base. Furthermore, in the embodiment, the viscoelastic body 7 had a circular cross section and a spherical surface in contact with the actuator 2, as shown in FIG. I don't mind.

(Effects of the Invention) As explained above, in the present invention, since a viscoelastic body is interposed between the optical base and the actuator, the actuator and the optical base are less susceptible to mutual photographing effects.
A high-performance optical pickup can be realized even in the face of disturbances.

[Brief explanation of drawings]

1 and 2 are an exploded perspective view and a schematic sectional view showing an embodiment of the invention, respectively, and FIG. 3 is an exploded perspective view of a conventional optical pickup. 1-m-objective lens, 2-m-actuator, 3-m
-Optical base, 41.42, 43.44---Coil spring 51.52,
53.54---Screw hole, 61.62, 63.64---
-screw, 7--viscoelastic body, 8-m-information carrier.

Claims (1)

[Claims] (1) An optical pickup in which an actuator for driving an objective lens is attached to an optical base so that its attachment angle can be adjusted, characterized in that a viscoelastic body is interposed between the actuator and the optical base. .