JPS59195339A - Optical pickup - Google Patents

Abstract

PURPOSE:To decrease the number of control manhours and to improve a record/ reproduction characteristic and the interchangeability by component parts, by attaching an elastic support member to a housing so that it can move within a plane orthogonal to the optical axis of an ojective lens and controlling the verticality between the optical axis of the objective lens and the bottom surface of an optical pickup. CONSTITUTION:The light delivered from an He-Ne laser 24 is reflected verti- cally by a reflecting mirror 21 and fed back to the output window of the laser 24 along the same optical path as long as the center axis BB of a lens barrel 11 is vertical to a base 22, i.e., the lower surface of a housing 18. If the axis BB is not vertical to the surface 20, the attachment position of an elastic support member holder 17 is moved to raise up the upper end of the barrel 11 in order to feed back the reflected light given from the mirror 21 to the output window of the laser 24. Thus the axis BB can be set vertical to the attachment surface of an optical pickup. As a result, the optical axis AA of an objective lens 10 which is stored coaxially to the barrel 11 is also set vertical to the attachment surface of the optical pickup.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is an optical system that uses a laser as a light source to focus light onto a recording track formed on a disk-shaped recording medium (hereinafter referred to as a disk) to record or reproduce information. This invention relates to an optical pickup used in a recording/reproducing device.

Conventional Structure and Problems In an optical recording and reproducing apparatus, the recording and reproducing characteristics are determined by the focusing state of the light beam on the recording track, that is, by the aberration on the focal plane.

Factors that adversely affect this light condensing state include vertical deviation between the disk and the optical axis of the objective lens housed in the optical pickup, and inclination between the laser optical axis and the objective lens optical axis.

Reducing the perpendicularity deviation between the objective lens optical axis and the disk and the inclination between the laser optical axis and the laser optical axis is a major adjustment item for the optical recording/reproducing device.

Hereinafter, the optical pickup in the conventional example will be explained using FIG. The disk 1 is attached to a turntable 2 coaxially attached to a motor 3 and rotates around two axes in the figure. - The light emitted from the male conductor laser 4 has its optical path changed by a mirror 5 and is incident on an objective lens 7 housed in an optical pickup 6. In addition, semiconductor laser 4. An optical unit 9 including a commameter lens, a quarter wave plate, a beam splitter, a photodetector, etc. (not shown) is attached to the carriage 8, and together with an optical pickup 6 attached to the optical unit 9, it is possible to perform, for example, a stepping device. The disk 1 is transported in the radial direction by a motor.

Disk 1 in an optical recording/reproducing apparatus having such a configuration
The vertical deviation between the optical axis of the semiconductor laser 4 and the optical axis of the objective lens 7 and the inclination of the optical axis of the semiconductor laser 4 and the optical axis of the objective lens 7 are caused by processing errors and the like. It is assumed that this is due to the perpendicularity deviation of the optical axis.

However, as seen in, for example, Japanese Unexamined Patent Publication No. 53-120403, an external optical pickup amplifier does not have a means for correcting perpendicularity deviation in the optical pickup alone.

Therefore, in the conventional example, the disk 1 and the objective lens 7
The perpendicularity deviation is adjusted by rotating the turntable 2 or the carriage 8 instead of the X and Y axes in the figure so that the recording and reproducing characteristics of the entire optical recording and reproducing device are optimized after assembly. Ta.

Still, the inclination of the optical axis of the semiconductor laser 4 and the optical axis of the objective lens 7 is adjusted so that the recording and reproducing characteristics are similarly optimized.
I adjusted it by rotating it.

Such an adjustment method has the disadvantage that it not only requires a large amount of adjustment man-hours, but also that it is difficult to obtain mutual compatibility between parts.

Purpose of the Invention The optical pickup of the present invention solves the above-mentioned problems of the conventional example, and makes it possible to adjust the perpendicularity deviation between the lower surface of the optical pickup and the optical axis of the objective lens, thereby reducing the number of adjustment steps and improving the optical pickup and optical unit. The purpose is to provide mutual compatibility for component conversions such as.

Structure of the Invention The optical pickup amplifier of the present invention includes an objective lens that focuses light on a recording track on a disk surface, a lens barrel that houses the objective lens, and a first lens barrel provided on the outer periphery of the lens barrel. The housing is provided with a magnet unit that generates electromagnetic force in cooperation with the first and second moving coils, and the lens barrel can be moved freely during focusing drive and tracking drive. Two elastic films (E) are placed at both the top and bottom ends of the lens barrel to support the lens barrel, and the structure allows the lens to be movably mounted to the housing within a plane orthogonal to the optical axis of the objective lens. By adjusting the position of the elastic member in the housing, it is possible to adjust the perpendicularity of the objective lens optical axis to the bottom surface of the housing, that is, the perpendicularity of the optical pickup to the surface. An optical recording and reproducing device can be constructed from a single optical pickup with tilt adjustment, an optical unit (=,,), and a turntable, which reduces the number of adjustment steps and also provides mutual compatibility between parts. Description of an Embodiment Next, an embodiment of the present invention will be described with reference to FIGS. 2 and 3.

FIG. 2 is a plan view of an optical pink-up according to an embodiment of the present invention, and FIG. 3 is a sectional view thereof. In FIGS. 2 and 3, reference numeral 11 denotes a lens barrel housing the objective lens 10;
2ia and 12b are fixed to the lens barrel 11, and the movable coinope 13 for tracking drive is also a 1-way moving coil for focus drive; 14J14b is a tracking drive magnet unit fixed to the barrel 18; 15 is also for focus drive It is a magnet unit. The lens barrel 11 is movably and elastically supported by elastic support members 16ia and 16b.

Therefore, as is well known, the focus control signal or the tracking control signal is
&, when 12b is energized, the magnet y=-nol-14&
, 14b, 16 - An electromagnetic force according to C-YV Mining's left-hand rule is generated, and the lens mirror 11 housing the objective lens 10 is connected to the elastic support member 16 & , 15b.
The lens is elastically supported and moved to correct focus errors or traso-kink errors.

The elastic support portion 4116b is coaxially engaged with the lens barrel 11 and the housing 18. On the other hand, the inner peripheral part of the elastic support part paulownia 16a is engaged with the lens barrel 11, and the outer peripheral part is engaged with the elastic support part paulownia holder 17.

This elastic support member holder 17 is attached to the housing 18 with screws 19.
Although attached by a to 19d, holder 1
Since the through hole provided in 7 is larger than the thread diameter, it is movable in the XX direction and the YY direction in the figure.

With the above configuration, the optical axis AA of the objective lens can be made perpendicular to the lower surface 2o of the housing 18, that is, aligned with the Z axis, by the means shown in FIG.

FIG. 4 is an explanatory diagram of an adjustment method in an optical pickup according to an embodiment of the present invention.

In the figure, (7) 11, 16&, 16b, 17, 18°20 indicate the same members as in FIGS. 2 and 3.

Reference numeral 21 denotes a reflecting mirror installed inside the lens barrel 11, and 22 denotes a base on which an optical pickup is mounted. He-
The light emitted from the Ne laser 24 is set by the rotating mirror 23 so that it is perpendicularly incident on the base 22. If the light from the He-Ne laser 24 is perpendicular to the lower surface 20 of the body 18, it will be reflected vertically by the reflection mirror 21 and follow the same optical path to become He-N.
It returns to the emission window of the e-laser 24.゛Therefore, when the elastic support member holder 17 is not vertical, the position of the elastic support member holder 17 is moved so that it is mounted at the upper end of the lens barrel 11 so that the reflected light from the reflection mirror 21 returns to the exit window of the He-Ne laser 24. As a result, the optical axis of the objective lens 10 coaxially housed in the lens barrel 11 can be In AA, the profit is also perpendicular to the target. In this way, it is convenient to adjust the optical axis tilt of the optical pickup alone, so the iJ of the optical recording and reproducing device is
It is possible to reduce the number of assembly steps, and when replacing parts, mutual compatibility can be obtained, which has great practical value. In this embodiment, the optical axis inclination is adjusted using four screws 19a to 19(i), but for example, the elastic support member holder 17 and the housing 18 are attached by adhesive, and the positioning is done at the time of adhesion. A similar effect can be obtained by using this configuration.

Furthermore, in the embodiment, among the two elastic support parts 4F,
Elastic support part A on the disk side 16? Although the configuration is such that only the elastic support member L is movable, a configuration in which only the elastic support member '16b is movable, or a configuration in which only the elastic support member paulownia 16a, 16 is movable is adopted.
An effect similar to that of the above-mentioned embodiment can be obtained even if both of b are movable.

Advantages of the Invention As described above, according to the present invention, the elastic supporting part paulownia can be moved into the housing within a plane that is direct to the optical axis of the objective lens, so that the optical axis of the objective lens and the optical pickup can be moved. By making it possible to adjust the perpendicularity to the bottom surface, it is possible to improve the recording and reproducing characteristics of optical recording and reproducing devices, reduce the number of adjustment steps, and achieve mutual compatibility between parts, which has great industrial value. Extremely large 0

[Brief explanation of the drawing]

FIG. 1 is a diagram of the principle of an optical pickup in a conventional example, FIGS. 2 and 3 are a plan view and a cross-sectional side view of an optical pickup in an embodiment of the present invention, and FIG. 4 is a diagram of the optical axis in the optical pickup. FIG. 7 is a cross-sectional view for explaining tilt correction adjustment. 10... Objective lens, 11... Lens mirror direction, 152L, 16b... Elastic support part removed, 17
...Elastic support member holder, 18...Housing, i
9 a, 19 b+190.19C1...
·screw. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 4
Figure 24

Claims (1)

[Claims] An objective lens that focuses light emitted from a light source onto a recording track formed on a disk-shaped recording medium, a lens barrel that houses this objective lens, and a first lens barrel provided on the outer periphery of this lens barrel. and a second movable coil, the housing has a housing that cooperates with the first coil to drive the lens barrel in the optical axis direction of the objective lens, and cooperates with the second coil. and a magnet unit for driving the lens barrel in the radial direction of the recording track, and two elastic supports fixed to the lens barrel and supporting the lens barrel so as to be elastically movable in the two directions. An optical pickup, wherein at least one of the widths of the elastic support portions is attached to the housing so as to be movable within a plane perpendicular to the optical axis of the objective lens.