JPH0413231A - Optical pickup - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to an optical pickup used in an optical recording/reproducing device.

"Prior art and its problems" The optical pickup used in the conventional optical recording and reproducing device is
As shown in FIG. 3, electromagnetic force is used as a driving source when driving the lenses 12 and 12' forming the optical pickup.

In order to support the lens 12.12 in such a case, the second
As shown in the figure, a plate spring type using spring 13 and a third
There is a shaft sliding type as shown in the figure.

In the case of a type that uses a spring, it is difficult to suppress the natural vibration of the spring, particularly the high-order vibration #l, and it is not suitable for a type that rotates a magneto-optical recording disk at high speed. In addition, in the case of the shaft sliding type, the current amount is considered to be reasonable, but it tends to get caught when sliding at low speeds.
The fit between the shaft and bearing is required to be precise.

It also has disadvantages such as increased size.

An object of the present invention is to solve these problems and provide a compact optical pickup that does not generate high-order resonance.

"Means for Solving the Problems" In order to solve the above-mentioned problems, the present invention consists of at least a part of the outer periphery of the lens barrel supporting the lens on the upper surface, and that the opposing side walls of the lens barrel are made of permanent magnets. A pair of first permanent magnet members are provided on the side facing the surface, and a pair of second permanent magnet members each having a coil wound thereon are provided on the other opposing surface, so that the first permanent magnet member can rotate the lens barrel. The optical pickup was configured to magnetically levitate.

"Function" Since the structure is as described above, the lens barrel is magnetically levitated by the permanent magnet provided on the mirror 4 itself that supports the lens, and the two opposing permanent magnet members). Can be supported by contact.

r"jil: m example" Embodiments of the present invention will be described in detail below with reference to the drawings.

The first percent is an example showing the optical pickup of the present invention.

In the figure, FIG. 1 shows an optical pickup according to the present invention in which a mirror I43 supporting a lens 2 is made of a permanent magnet. Lens barrel 3 is formed into a rectangle.

Of course, it can be constructed in a cylindrical or oval shape, but in the one-piece embodiment, a rectangular shape is shown for ease of explanation.

The permanent magnet of the lens barrel 3 formed in this way is the lens l.
It is magnetized in the direction perpendicular to the optical axis. The direction of magnetization is such that the outside is the north pole. A permanent magnet 4.5 is placed opposite the opposite side of the rectangular mirror 1r13. This permanent magnet plate 4
．． The direction of magnetization of lens 5 is the same as the direction of magnetization of lens barrel 3, so that the magnetic poles face each other. The gap between the lens barrel 3 and the permanent magnet plate 4.5 is kept very small, for example, about 011 mm. Permanent magnet plates 6 and 7 are arranged on the other opposite side of the lens barrel 3, and a tracking coil is wound around the permanent magnet plates 6 and 7.

A permanent magnet plate with a tracking coil wound thereon, similar to the permanent magnet plate 6, is also provided on the upper front side of the figure, but it is omitted because the figure is inward.

By passing current through this coil 8.9, the lens barrel 3 can be driven slightly left and right. Permanent magnet plate 4.5
and the permanent magnet @6.7 around which the coil 8.9 is wound, have a recess of, for example, approximately 015 mm, and the coil 10 is placed in this recess so as to surround the lens barrel 3.

By passing current through this coil 10, the lens barrel can be driven in the optical axis direction to perform focusing.

Since the optical pickup of this embodiment is constructed as described above, the lens barrel 3 is magnetically levitated, so that there is no friction and smooth driving is possible. Note that the present invention is not limited to the above-mentioned embodiments, and the lens barrel may be configured to have a cylindrical shape, for example. It is also possible to consider a type in which the diagonal parts of the rectangle are made up of L-shaped permanent magnets and the permanent magnets are driven by a coil. Furthermore, since there is no mechanical contact between the lens barrel and the lens barrel, there is no possibility of twisting. It has remarkable effects such as external vibrations are not transmitted to the lens side, there is no wear, and since no springs are used, there is no adverse effect of high-order vibrations that are inherent to springs.

[Brief explanation of the drawing]

Fig. 2 is a partially omitted assembly view of an optical pickup according to an embodiment of the present invention, Fig. 2 is a perspective view showing a conventional leaf spring type optical pickup, and Fig. 3 is a conventional shaft sliding type optical pickup. FIG. 3 ・ ・ ・ Lens barrel 4.5.6, 7...Permanent & a stone plate Patent applicant Kyocera Corporation "Effects of the invention j As described above, the present invention has a lens barrel made of a permanent magnet with a large coercive force. By configuring this structure, the lens barrel can be made lightweight.Therefore, the whole can be made small and lightweight, which is very advantageous when seeking at high speed. 1991 Ritsuki/Sunset

Claims (2)

[Claims] (1) At least a part of the outer periphery of the lens barrel supporting the lens on the upper surface is made of a permanent magnet, and a pair of first permanent magnet members are provided on the side facing the opposing surfaces of the side walls of the lens barrel, and An optical pickup characterized in that a pair of second permanent magnet members having coils wound thereon are provided on opposing surfaces of the optical pickup, and the lens barrel is magnetically levitated by the first permanent magnet member. (2) The optical pickup according to claim 1, wherein a coil is wound around a side wall of the lens barrel, and the lens barrel is driven in the optical axis direction by passing a current through the coil.