JPS6112594Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention focuses on the focusing position of a signal reading beam on a track formed on a video disk, for example.
An optical disk player signal reading device which uses an optical pickup to detect the reflected reading beam itself, and controls the optical pickup in the optical axis direction and in a direction perpendicular thereto by an electromagnetic drive mechanism using a magnetic circuit. Regarding improvements.

FIG. 1 is a sectional view showing a conventional signal reading device. In the figure, A is an optical pickup section, and B is a laser beam projecting/receiving section equipped with an objective lens, a semiconductor laser, etc. C is a magnetic circuit for driving the above-mentioned optical pickup section A in the optical axis direction. This magnetic circuit C has almost the same configuration as a general-purpose electrodynamic speaker magnetic circuit, and has a ring-shaped magnet D.
, a pole yoke E, and a plate G, and a magnetic gap H is formed between the plate G and the pole yoke E. A voice coil fixed to the optical pickup section A is disposed within the magnetic gap H, and the optical pickup section A is thereby driven in the direction of the optical axis. The light emitting/receiving section B is driven in a direction perpendicular to the optical axis by a tracking coil F and a tracking magnetic circuit (not shown). J is the optical pickup section A mentioned above.
The light emitting/receiving part B of the optical pickup part A is slidably inserted into the inner cylinder K of this bearing J, and the inner cylinder part K and It is fixed via an elastic body L. The outer cylinder M is fixed to the inner wall of the pole yoke E with an adhesive. However, as mentioned above, since the outer cylinder M of the tracking bearing J is fixed to the inner wall of the pole yoke E with adhesive, the reliability of the fixed part decreases during long-term use. Since the inner diameter of the pole yoke E is determined by the outer diameter of the outer cylinder M, the magnetic circuit C has to be large.

Therefore, in order to solve the above-mentioned drawbacks, the present invention improves the reliability of the fixed part of the tracking bearing to the pole yoke by providing a notch in the inner wall of the pole yoke into which the outer cylinder fits. It is an object of the present invention to provide an optical disc player signal reading device that can be expected to have improved performance and miniaturization of the magnetic circuit.

Hereinafter, the present invention will be explained based on the embodiments shown in the drawings. Fig. 2 is a sectional view of a signal reading device according to the present invention, and Fig. 3 is a perspective view with a part of the tracking bearing used in the device cut away. A diagram is shown. In the drawing, 1 is an optical pickup section;
Reference numeral 2 denotes a laser beam projecting/receiving section equipped with an objective lens, a semiconductor laser, and the like. 3 is a magnetic circuit with almost the same configuration as a general-purpose electrodynamic speaker magnetic circuit,
A ring-shaped magnet 4, a pole yoke 5,
A magnetic gap 8 is formed between the plate 7 and the pole yoke 5. A voice coil 9 fixed to the optical pickup section 1 is disposed within the magnetic gap 8, and the optical pickup section 1 is thereby driven in the direction of the optical axis (up and down in the figure). The light emitting/receiving section 2 is driven in a direction perpendicular to the optical axis by a tracking coil 15 and a tracking magnetic circuit (not shown). Reference numeral 10 denotes a tracking bearing that supports the optical pickup section 1 so as to be slidable in the optical axis direction and swingable in a direction perpendicular to the optical axis direction. An inner cylinder 11 made of a non-magnetic material that slidably accommodates the light emitting/receiving part 2 of the optical pickup part 1, and an elastic cylinder 1 fitted to the outer periphery of the inner cylinder 11.
2, and an outer cylinder 13 fitted around the outer periphery of the elastic cylinder 12. Here, the outer cylinder 13 is formed of a magnetic material, and it is desirable that its magnetic permeability is equivalent to that of the pole yoke 5. On the other hand, the upper end of the inner wall of the pole yoke 5 is formed with a notch 14 having a shape corresponding to the outer cylinder 13 into which the outer cylinder 13 of the tracking bearing 10 is hermetically fitted and fixed. 14, and 14b is a stepped portion thereof.
Incidentally, the inner cylinder 11 of the tracking bearing 10 may be removed and the light emitting/receiving part 2 of the optical pickup part 1 may be inserted into the elastic cylinder 12, but it is not necessary to avoid the influence of changes over time such as wear. Inner cylinder 11 made of magnetic material
The hotter the better.

As described above, the tracking bearing 10 is constructed by fitting and fixing the outer cylinder 13 into the notch 14 formed in the inner wall of the pole yoke 5, so that the outer cylinder 14 is connected to the inner circumferential surface 14a of the notch 14 and the step. 14b, the contact area is widened, and the tracking bearing 10 is prevented from rattling with respect to the pole yoke 5, improving the reliability of fixation. Furthermore, by forming the outer cylinder 13 of the tracking bearing 10 from a magnetic material, saturation of the magnetic flux due to the formation of the notch 14 can be prevented. The inner diameter of the pole yoke 5 can be made smaller than the outer diameter, and the outer diameter of the magnetic circuit 3 can be made smaller accordingly.

As mentioned above, the present invention includes a magnetic circuit 3 consisting of a pole yoke 5, a magnet 4, etc.
an optical pickup section 1 driven in the direction of the optical axis and a direction perpendicular thereto by a magnetic circuit including a coil F having the same configuration as the above, and at least an outer tube 13 and an elastic tube 12 fitted on the inner surface thereof. In an optical disc player signal reading device comprising an optical pickup section 1 and a tracking bearing 10 supporting the inner wall of a pole yoke 5,
The outer cylinder 13 of the tracking bearing 10 is made of a magnetic material, and the inner wall of the pole yoke 5 is provided with a notch 14 into which the outer cylinder 13 is fitted and fixed. The fixation is secure, and reliability can be expected for long-term use. Furthermore, by forming the outer cylinder 13 from a magnetic material, saturation of the magnetic flux due to the formation of the notch 14 on the inner wall of the pole yoke 5 can be prevented, and the formation of the notch 14 also prevents the magnetic circuit 3 from becoming saturated. The outer diameter size can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional signal reading device,
FIG. 2 is a cross-sectional view of the signal reading device according to the present invention.
FIG. 3 is a partially cutaway perspective view of the tracking bearing used in the device. 1... Optical pickup section, 3... Magnetic circuit,
4...Magnet, 5...Pole yoke, 10...
...Tracking bearing, 11...Inner cylinder, 12
...Elastic cylinder, 13...Outer cylinder, 14...Notch.

Claims (1)

[Scope of utility model registration request] an optical pickup section, a magnetic circuit including a pole yoke, a magnet, etc. for driving the optical pickup section in the optical axis direction; a driving means for driving the optical pickup section in a direction perpendicular to the optical axis; In an optical disk player signal reading device, the optical disk player signal reading device is comprised of a tracking bearing, which is made up of an elastic cylinder fitted on the inner surface of the tracking bearing, and supports the optical pick-up part on the inner wall of the pole yoke. An optical disc player signal reading device that is made of a magnetic material and has a notch formed in an inner wall of the pole yoke to fit and fix the outer cylinder.