JPS59231746A - Optical pickup - Google Patents

Abstract

PURPOSE:To improve record/reproduction characteristics by providing at least a pushing hole for objective lens to the side face of a lens holder and putting a pushing pin for objective lens into said hole in order to control the tilts of both the center axis of the lens holder and the optical axis of the objective lens. CONSTITUTION:Pushing pins 15a and 15b for objective lens are put into holes 14a and 14b of a lens holder 13 respectively and then pressed to the side face of an objective lens 12. Thus the lens 12 is shifted to the position shown by a broken line from the position shown by solid line. Then the bus bar on the side face of the lens 12 is joined to the inside face of the holder 13, and the center axis of holder 13 as well as the optical axis of the lens 12 have no tilt. Under such conditions, an adhesive is filled into a gap at the fitted part between the lens 12 and the holder 13 to adhere the lens 12 to the holder 13. In such a way, the tilt can be controlled for both the optical axis of the lens 12 and the center axis of the holder 13 respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is a method for recording or reproducing information by using a laser as a light source to form on a disk-shaped recording medium (hereinafter referred to as a disk) and focusing the light onto a recording trunk. This invention relates to an optical pickup used in an optical recording/reproducing device.

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

Factors that adversely affect this light focusing state include the perpendicularity between the disk and the optical axis of the objective lens, the inclination between the laser optical axis and the objective lens optical axis, and the inclination between the disk and the objective lens optical axis. Reducing the perpendicularity deviation and the inclination between the laser optical axis and the objective lens optical axis are major adjustment items for optical recording and reproducing devices.

Hereinafter, the optical pickup in the conventional example will be explained using FIG. The disk 1 is attached to a turntable 3 coaxially connected to a motor 2 and is rotated about the Z-axis in the figure.

On the other hand, the light emitted from the semiconductor laser 4 is reflected by the mirror 6.
The optical path of the light is changed by the light beam, and the light enters an objective lens 9 in a lens barrel 8 housed in a lens holder 7 in a light pink-up 6. Also, semiconductor device boot 4. An optical unit (including a collimator lens, a 21/4 wavelength plate, a beam splitter 1 photodetector (not shown), etc.) 10 is a carriage 11
attached to the optical unit 10 and attached to the optical unit 11.
The optical pickup 6 is transported in the radial direction of the disk 1 by, for example, a stepping motor.

Generally, the objective lens of an optical recording/reproducing device is a combination lens (objective lens 9) housed in a lens barrel 8.For simplicity, the objective lens 9 including this lens barrel 8 will be described below. I will call it.

In an optical recording/reproducing apparatus having such a configuration, the perpendicularity deviation between the optical axis of the disk 1 and the objective lens 9 and the inclination between the optical axis of the semiconductor laser 4 and the optical axis of the objective lens 9 are caused by the lens holder due to processing errors, etc. This is largely due to the inclination of the central axis of lens 7 and the optical axis of objective lens 9.

However, the optical pink-up 6 in the conventional example did not have a means for correcting the inclination between the central axis of the lens holder 7 and the optical axis of the objective lens 9.

Purpose of the Invention The present invention is intended to improve the drawbacks seen in the above-mentioned conventional examples, and to improve the recording and reproducing characteristics by making it possible to adjust the inclination of the central axis of the lens holder and the optical axis of the objective lens. purpose.

Structure of the Invention The optical pickup of the present invention includes at least an objective lens that focuses light on a recording track on a disk surface, and an objective lens pressing hole in a side surface into which an objective lens pressing pin can be inserted in a direction perpendicular to the central axis of the objective lens. The lens holder includes one lens holder for housing the objective lens, and means for driving the lens holder in the thickness direction and radial direction of the disk.

By fixing the objective lens to the lens holder while pressing the objective lens in the direction perpendicular to the central axis of the lens holder through this objective lens suppression hole, the inclination between the central axis of the lens holder and the optical axis of the objective lens can be reduced. You can reduce it. Therefore, the recording and reproducing characteristics of the optical recording and reproducing device can be improved.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 2 and 3.

FIG. 2 is a front view of a lens holder housed in an optical pickup according to an embodiment of the present invention, and FIG. 3 is a sectional view of the lens holder. In FIGS. 2 and 3, 12 is an objective lens;
3 is a lens holder that houses this objective lens 12; 14a, 14. b is an objective lens suppression hole provided at the center position of the height of the objective lens 12 in the perpendicular direction to the center axis of the lens holder 13, so that the center axes are perpendicular to each other; These are objective lens suppressing pins inserted into the objective lens pressing holes 14a and 14b, respectively, to press the measured surface of the objective lens 12 in a direction perpendicular to the central axis of the lens holder 13.

The parts of the objective lens pressing pins 1sa and 1sb that are inserted into the lens pressing holes 14a and 14b are as follows:
It has a cylindrical shape whose diameter is slightly smaller than the diameter of the objective lens pressing holes 14a and 14b. In Figures 2 and 3, Z is lens holder 1s <D in the central axis direction,
The axis and Y axis are objective lens pressing holes 14a and 14b, respectively.
It is placed in the direction of the central axis.

When the objective lens pressing pins 15a, 15b are inserted into the objective lens pressing holes 14a, 14b, and pressed against the side surface of the objective lens 12, the objective lens pressing pins 15a, 15b and the objective lens pressing hole are inserted. 14a, 1
Since the diameters of the inserted portions of 4b are almost equal, the objective lens 1
The objective lens 12 is suppressed in the direction perpendicular to the Z-axis, that is, the central axis of the lens holder 13 (16a is the X-axis direction in the figure, and 15b is the Y-axis direction in the figure) in the full side view of 2. As a result, the objective lens 12 is From the state of the solid line to the state of the broken line in the figure, the generatrix of the side surface of the objective lens 12 is joined to the inner surface of the lens holder 13, and the optical axis of the n1 objective lens 12 and the Z axis in the figure, that is, the central axis of the lens holder 13. In this state, adhesive is poured into the gap between the fitting part of the objective lens 12 and the lens holder 13, and the objective lens 12 is glued to the lens holder 13.
The optical axis of the objective lens 12 and the central axis of the lens holder 13 are not tilted.

In this way, it is possible to adjust the inclination of the central axis of the lens holder and the optical axis of the objective lens.1. Recording in an optical recording/reproducing device ('3) can improve readability.

Furthermore, although two objective lens suppression holes are provided in this embodiment, the same effect can be obtained with one or three or more holes.

As described in detail, the optical pickup according to the present invention has at least one objective lens suppression hole provided in the side surface of the lens holder in a direction perpendicular to the center of the lens holder, and the objective lens is inserted into the objective lens suppression hole. By making it possible to insert a suppression bottle, it is possible to adjust the inclination Ax between the objective 1/lens optical axis and the central axis of the lens holder, improving the recording and reproducing characteristics of the optical recording and reproducing device, and improving its industrial performance. I
The IIIi value is extremely large.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the principle configuration of optical pickup in a conventional example.
Figure 2 shows the front view of the lens holder housed in the optical pickup in one embodiment of the present invention.
It is a sectional view taken along the -X' line. 12...Objective lens, 13...Lens holder 114a, 14b...Objective lens pressing hole, 16a. 16b...Pin O for pressing the objective lens Name of agent Patent attorney Toshio Nakao and one other person Figure 1 Figure 2'' Figure 3 Figure l?

Claims (1)

[Claims] an objective lens that focuses light emitted from a light source onto a recording track formed on a disc-shaped recording medium; a lens holder having a storage space for housing the objective lens; A through hole penetrating into the storage space, an objective lens suppression pin inserted into the through hole and whose tip abuts the objective lens Vζ in the storage space, and a lens holder for the objective lens in the thickness direction and radial direction of the disk-shaped recording medium. An optical pickup characterized by comprising: means for driving the optical pickup.