JPS60164936A - Angle correcting device of optical pickup - Google Patents

Abstract

PURPOSE:To attain miniaturization and light-weight of a moving part and to improve the operability by constituting the moving part slided along a rail in radial direction, of a disc consisting of only an optical pickup and its associated components, and providing a correction drive means to keep the angle between the disc and the objective lens optical axis to 90 deg.C between the moving part and a fixed part. CONSTITUTION:The optical pickup 5 is moved on rails 2a, 2b from the outermost circumference to the innermost circumference of the disc 11 in parallel to reproduce information recorded on the disc 11. If the optical axis 10a of an objective lens 10 is not perpendicular to the face of the disc 11 in this case, a difference signal appears by the objective lens 10 by photodetectors 9a, 9b. Since a motor 3 is driven based on the difference signal, a plate 51 is turned around the tangential direction of a disc circumference around pins 6a, 6b. Thus, the angle between the disc face and the optical axis 10a of the objective lens 10 is corrected and the angle is formed perpendicularly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical pickup angle correction device that uses a laser beam to read information recorded on a disk.

The general recording and reproducing method for optical pickups is to irradiate a laser beam generated from a laser diode or the like onto the disk surface using an objective lens, and convert changes in the amount of reflected light depending on the presence or absence of pits into changes in current. , for playback. At this time, if the angle of the optical axis of the objective lens with respect to the disk surface is not perpendicular (90 degrees), the beam spot on the disk will be distorted, making it impossible to obtain a stable reproduced signal. In particular, near the outer periphery of the disc, due to the disc's deflection due to its own weight, the above angle should be changed to 90°.
difficult to maintain. Therefore, in order to always keep the objective lens optical axis and the disk surface straight, a mechanism for correcting the optical axis angle is required.

Hereinafter, the conventional device will be explained with reference to FIG. 1 of the accompanying drawings.

FIG. 1 is a perspective view of a configuration example of a conventional device.

The base 1 has rails 2a, 2 arranged parallel to each other.
It is slidably supported by b. A motor 3 and a speed reduction device 4 are provided on the base 1, and an optical pickup 5 or a pin 6a for reading information from the disk 11 is provided.
, 6b is rotatably attached to the base 1. The male screw 7a at the tip of the output shaft 7b of the drive shaft connected to the reduction gear 4 is screwed into the female screw part of the optical pickup 5, and on the upper surface of the optical pickup 5 there is a light emitting element 8 and a pair of light emitting elements sandwiching it. Light receiving elements 9a, 9I) are provided. A disk 11 is located in the center of the optical pickup 5.
An objective lens 10 is provided opposite to. The disk 11 is picked up by a spindle motor 13 via a clamper 12 and rotated in a predetermined direction.

Next, the operation of the configuration example shown in FIG. 1 will be explained.

The optical pickup 5 reproduces information recorded on the disk 11 by moving the base 1 in parallel on the rails 2a and 2b from the innermost circumference of the disk to the outermost circumference of the disk.

At this time, in order to obtain a reproduced signal without disturbance, it is necessary that the angle between the optical axis of the objective lens 10 and the disk 11 be 90 degrees (perpendicular). However, on the outer periphery of the disk, even when rotating, the disk 1 due to its own weight.
1 is often bent and unable to maintain verticality, leading to disturbances in the reproduced signal.

In order to correct this, the following is done. First, light is emitted from the light emitting element 8 to the disk 11, and the reflected light is received by the light receiving elements 9g and 9b, and the verticality is detected from the difference in the amount of received light. At this time, when the optical axis of the objective lens 10 and the disk 11 are perpendicular, the light receiving element 9a
, 9b have the same amount of light reception, and no current flows (no difference signal flows). If the verticality shifts, a difference will appear in the amount of light received, so
A positive or negative current flows 4 depending on the inclination of the optical axis (a difference signal flows). This current is applied to the motor 3, causing the motor 3 to rotate.

Since the rotation of the motor 3 is transmitted to the output shaft 7b via the decelerator @4, the optical pickup is moved by the screw action between the male thread 7a and the female threaded portion of the optical pickup 5 through the pins 6a, 6.
It is rotated around b in the tangential direction of the disk circumference. The direction of rotation corresponds to the positive and negative currents, ie, the direction of the inclination of the optical axes of the disk 11 and the objective lens 10. When the optical axes of the disk 11 and the objective lens 10 become perpendicular, the difference signal becomes O, and the motor 3 stops.

By repeating the above operations and keeping the optical axis of the objective lens 10 perpendicular to the disk 11, a reproduced signal without disturbance is obtained.

However, in the conventional device as described above, the slider (movable part) that moves in the radial direction of the disk along the rail needs to have a dual structure consisting of an optical pickup and a base, which increases the size of the movable part and makes it difficult to operate. The drawback was that it became worse. Further, there was a drawback that the assembly of the device was complicated and the cost was high.

The present invention has been made to overcome the drawbacks of the above-mentioned conventional devices, and an object of the present invention is to provide an optical pickup angle correcting device that is simple in construction and has good operability.

In order to achieve the above object, the present invention has several optical pickups slidably mounted on a rail, and the rails are rotated in the tangential direction of the disk circumference by a rail drive device, thereby moving the disk and the optical pickup. An object of the present invention is to provide an angle correcting device for an optical pickup, which is capable of correcting the angle formed between the optical axis of the optical pickup and the optical axis of the objective lens.

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 2 and 3 of the accompanying drawings.

FIG. 2 is a perspective view of the same embodiment. Note that the same elements as in the conventional example are indicated by the same reference numerals. An optical pickup 5 is supported on rails 2a and 2b arranged in parallel on the plate 1-51 in a slidable manner in the radial direction of the disk 11, and this plate 5I is supported by pins provided on both sides of the central portion. 6
a and 6b, it is attached to a chassis 55 as a fixed part so as to be rotatable around the tangential direction of the disk circumference. The chassis 55 has a motor 3 and a reduction gear 4.
The output shaft 7b of the drive pulley 7 connected to the speed reducer 4 has a male thread 7a at its end, which is screwed into the female thread of the bracket 52 of the plate 51. Further, on the upper surface of the optical pickup 5, a light emitting element 8 and a pair of light receiving elements 9 are arranged.
a and 9b are provided to face the disk 11. Note that an assist spring 53 is stretched between the play 1 51 and the chassis 55.

FIG. 3 is an explanatory diagram of the configuration near the objective lens 10 in FIG. 2. The objective lens JO is located below the disk 11, and its optical axis 10a is controlled to be perpendicular to the surface of the disk 11.

Next, the operation of the embodiment shown in FIGS. 2 and 3 will be explained.

The optical pickup 5 connects the rails 2a and 2bJ to the disk 1.
The information recorded on the disc 11 is reproduced by moving in parallel from the innermost circumference to the outermost circumference of the disk 11. At this time, the objective lens 10
When the optical axis 10a of is no longer perpendicular to the surface of the disk 11,
Similar to the configuration example shown in FIG. 1, a difference signal appears by the light receiving elements 9a and 9b. Since the motor 3 rotates based on this difference signal, the play 1-51 is moved between the pins 6a,
It is rotated around 6b in the tangential direction of the disk circumference. As a result, the angle between the disk surface and the optical axis 10a of the objective lens 10 is corrected and always kept perpendicular.

As described above, according to the present invention, the movable part that slides along the rail in the radial direction of the disk is composed only of the optical pickup and its attached parts, and the angle between the disk and the optical axis of the objective lens is set to 90 degrees. Since a correction drive means is provided between the movable part and the fixed part to maintain the
It is possible to obtain an optical pickup angle correcting device that can improve operability and reduce costs by making the movable part smaller and lighter. Furthermore, since there is no need for the movable part to have a double structure of a base and an optical pickup, assembly becomes extremely easy. Note that at least one rail is sufficient as long as it can guide the optical pickup.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an example of the configuration of a conventional device, FIG. 2 is a perspective view of an embodiment of the present invention, and FIG. 3 is a configuration diagram of the vicinity of the objective lens in FIG. 2a, 2b...Rail, 5...Optical pickup, 11...Disc. Applicant Asahiko-Y Kogyo Co., Ltd.] Figure 1

Claims (1)

[Claims] At least one rail rotatable around the tangential direction of the circumference of the disk, an optical pickup mounted so as to be slidable in the radial direction of the disk along the rail, and an objective lens relative to the disk surface. detection means for detecting the angle formed by the optical axis and outputting a signal according to the deviation of the detected angle from 90 degrees; 1. An angle correction device for an optical pickup, comprising a correction drive means for maintaining an angle formed by an optical axis of an objective lens with respect to a disk surface at 90 degrees by rotating the optical axis around a direction.