JP2003217163A - Objective lens for optical pickup - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an objective lens for an optical pickup which can be reduced in the weight of a lens unit being a moving section of an optical pickup device and can be stabilized in an objective lens during high-speed access. <P>SOLUTION: The objective lens 2 for the optical pickup having a flange 3 integrally formed at the circumference of an optical function section 5 is provided with a buffer section 4 for protecting the optical function section 5 at the front end of the flange 3 formed on an optical disk 7 side. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an objective lens for an optical pickup used in an optical disk reproducing device such as a CD or DVD or an optical disk recording / reproducing device.

[0002]

2. Description of the Related Art In recent years, an optical pickup device is required to have high speed access. In order to speed up the access, it is necessary to move the objective lens to a desired place on the optical disk quickly. Therefore, it is desirable that the lens unit in which the objective lens is installed is lightweight.

The structures of the conventional optical pickup device 100 and lens unit 101 will be described with reference to FIGS. 4 and 5. FIG. 4 is a perspective view of a conventional optical pickup device. FIG. 5 is a schematic sectional view showing a configuration of a lens unit of a conventional objective lens for an optical pickup.

A conventional optical pickup device 100 is shown in FIG.
As shown in FIG. 3, the lens unit 10 suspended from the suspender wire 110 extending from the damper holder 109.
It has 1. The lens unit 101 includes an objective lens 102 for converging a laser beam on an information recording surface of an optical disc, a lens holder 111 for holding the objective lens 102, and a surface of the objective lens 102 provided on the lens holder 111. Protective cover 104 for
And the lens unit 10 provided on the lens holder 111.
A tracking coil 107 and a focusing coil 108 for moving 1 to a predetermined position are provided. The lens unit 101 also includes a pair of yokes 112.
It is positioned so as to be sandwiched between the magnets 106 provided in the.

Further, the objective lens 102 is an optical function unit 10.
5 and has a flange 103 around the optical function unit 105.
Is provided. The flange 103 is the lens holder 11
It is fixed at 1. A tracking coil 107 and a focus coil 108 are attached to the lens holder 111 and can be driven so that the position of the optical disk 113 can be adjusted in the track direction and the focus direction. In this way, the tracking coil 1
The position of the objective lens 102 can be adjusted by the action of 07 and the focus coil 108, and the laser light can be focused on the pits of the optical disc 113 to record / reproduce information on / from the optical disc 113.

The optical function section 10 of the objective lens 102 is also provided.
The distance between the optical disc 113 and the optical disc 113 is usually about 3 mm, and the objective lens 102 and the optical disc 113 may come into contact with each other due to a malfunction due to vibration or position adjustment in the focus direction, and both may be scratched. Therefore, in the conventional lens unit 101, a protective cover 104 having a shape that covers the objective lens 102 is provided on the side of the optical disk 113 of the lens holder 111, and the optical function unit 105 and the optical disk 1 are provided.
13 is prevented from making direct contact.

[0007]

However, in the above optical pickup device, since the protective cover of the objective lens is installed in the lens holder, the lens holder becomes heavy, which impedes the speeding up of access. Further, by providing the lens holder with the protective cover, the weight balance is inclined toward the objective lens side, and the shake of the objective lens due to inertial force during high-speed access becomes large. This has been one of the causes of slowing down the access speed of the optical pickup device.

The present invention has been made in view of such circumstances, and an optical pickup capable of reducing the weight of a lens unit, which is a movable part of an optical pickup device, and stabilizing an objective lens during high-speed access. An object of the present invention is to provide an objective lens for use.

[0009]

In order to solve the above-mentioned problems, an objective lens for an optical pickup according to a first aspect of the present invention is an objective lens for an optical pickup having a flange integrally formed around an optical function portion. In the above, a buffer portion for protecting the optical function portion is provided at a tip end portion of the flange provided on the optical disc side.

In the structure according to the first aspect, the buffer portion is provided at the tip of the flange provided on the optical disk side of the objective lens for the optical pickup to protect the optical function section from contact with the optical disk. Further, since the buffer portion is provided directly on the flange of the objective lens, the weight of the lens unit can be reduced.

Next, an objective lens for an optical pickup according to a second aspect of the present invention is characterized in that a plurality of the buffer portions are arranged at a distance from the tip of the flange.

In the structure according to the second aspect, by arranging a plurality of cushioning portions at a distance, it is possible to further reduce the weight because the cushioning portions at the distanced portions are unnecessary.

Next, the objective lens for an optical pickup according to a third aspect of the present invention is characterized in that the buffer portion is formed of a UV adhesive.

In the structure according to the third aspect, since the buffer portion is formed of the UV adhesive, the buffer portion can be formed only by the adhesive, so that the lens unit is lightweight and easy to manufacture.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION A configuration example of an embodiment of an objective lens for an optical pickup of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view showing a part of a lens unit of an optical pickup device according to an embodiment of the present invention.
FIG. 2 is a top view showing an objective lens for an optical pickup according to the first embodiment of the present invention. FIG. 3 is a top view showing an objective lens for an optical pickup according to a second embodiment of the present invention. In each drawing, the same components are designated by the same reference numerals, and duplicate description will be omitted.

As shown in FIG. 1, an objective lens 2 for an optical pickup according to an embodiment of the present invention is held on a ceiling portion of a lens holder 6 to form a lens unit 1. The lens unit 1 is provided with a tracking coil and a focusing coil and is arranged in the same manner as the conventional lens unit 101 shown in FIG.

(First Embodiment) An objective lens 2 for an optical pickup according to a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. The optical pickup objective lens 2 of the present invention is provided with an optical function part 5 for converging a laser beam in a pit of an optical disk 7, and a flange 3 integrally formed in an annular shape around the optical function part 5. A circular UV adhesive is printed along the tip of the flange 3 and then
The buffer portion 4a is formed by being cured by being irradiated with ultraviolet rays.

In this way, the objective lens 2 for optical pickup is used.
It is possible to prevent the surface of the optical function part 5 and the optical disk 7 from coming into direct contact with each other by printing the UV adhesive on the tip of the flange 3 provided on the optical disk 7 and forming the buffer part 4.
Further, the lens unit 1 is lightweight and easy to manufacture because it has a simple structure in which the UV adhesive is directly printed on the tip of the flange 3.

Further, with the above-mentioned structure, the weight of the ceiling portion of the lens holder 6 is reduced, and the weight balance of the lens unit 1 is stabilized. This reduces the shake of the objective lens 2 due to the inertial force during high-speed access.

(Second Embodiment) An objective lens 2 for an optical pickup according to a second embodiment of the present invention will be described with reference to FIGS. 1 and 3. The optical pickup objective lens 2 of the present invention is provided with an optical function part 5 for converging a laser beam in a pit of an optical disk 7, and a flange 3 integrally formed in an annular shape around the optical function part 5. A UV adhesive is printed at three positions at a distance from the tip of the flange 3, and the UV adhesive is irradiated with ultraviolet rays to be cured to form a buffer portion 4b.

In this way, the objective lens 2 for the optical pickup is
UV adhesive is printed on the tip of the flange 3 of the
By forming the surface of the optical function unit 5 and the optical disk 7
Can be prevented from coming into contact with each other. Further, since the UV adhesive is printed at a distance on the tip of the flange 3, a buffer portion at a distanced portion becomes unnecessary. As a result, the lens unit 1 can be further reduced in weight.

In the above embodiment, the buffer unit 4 is set to U.
Although a V adhesive is used, other configurations are also possible.
For example, a configuration in which a resin or the like having a hardness lower than that of the optical disc is adhered may be used. Further, the buffer portion may be formed of silicon gel or rubber. Further, in the second embodiment, the number of buffer portions is three, but any number of buffer portions may be used.

[0023]

As described above, according to the present invention, it is possible to reduce the weight of a lens unit, which is a movable part of an optical pickup device, and to stabilize an objective lens during high-speed access. It becomes possible to provide an objective lens.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a part of a lens unit of an optical pickup device according to an embodiment of the present invention.

FIG. 2 is a top view showing an objective lens for an optical pickup according to the first embodiment of the present invention.

FIG. 3 is a top view showing an objective lens for an optical pickup according to a second embodiment of the present invention.

FIG. 4 is a perspective view of a conventional optical pickup device.

FIG. 5 is a schematic sectional view showing a part of a lens unit of a conventional objective lens for an optical pickup.

[Explanation of symbols]

1 lens unit 2 Objective lens 3 flange 4, 4a, 4b buffer section 5 Optical function section 6 lens holder 7 Optical disc 100 Optical pickup device 101 lens unit 104 protective cover 107 tracking coil 108 Focusing coil

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Miki Takada             3-3-6 Nihonbashi Ningyocho, Chuo-ku, Tokyo               Sumida Applied Components Stock Association             In-house F-term (reference) 5D119 AA32 BA01 JA44 JC06 MA14                 5D789 AA32 BA01 JA44 JC06 MA14

Claims (3)

[Claims] 1. An objective lens for an optical pickup having a flange integrally formed around an optical function part, wherein a buffer part for protecting the optical function part is provided at a tip end part of the flange formed on the optical disc side. Objective lens for optical pickups. 2. The objective lens for an optical pickup according to claim 1, wherein a plurality of the buffer portions are arranged at a distance from a tip portion of the flange. 3. The objective lens for an optical pickup according to claim 1, wherein the buffer section is formed of a UV adhesive.