JPH04151618A - Rotary mirror device for tracking - Google Patents

Abstract

PURPOSE:To obtain a support mechanism whose angle of rotation is easily controlled and which is miniaturized by supporting a mirror holding member which holds a reflecting mirror rotatably by using a thin leaf spring or wire. CONSTITUTION:The reflecting mirror 10 is held by sticking the back of its reflecting surface on the mirror holding member 11, which is suspended by the leaf spring 12 and held. A driving coil 13 is wound around the flank of the mirror holding member 11, a yoke 14 and a repeating yoke 15 are provided across the coil 13, and a permanent magnet 16 is interposed between the yokes 14 and 15. The reflecting mirror 10 is rotated by the driving of the magnetic circuit consisting of the yoke 14, repeating yoke 15, and magnet 16, and the driving coil 13 and two twist parts 12c of the thin leaf spring 12 are the centers of rotation. Consequently, the rotational attitude of the reflecting mirror is made secure, the control is easy, and the size reduction is facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotating mirror device for tracking used in an optical head of an optical disc device, for example, to make a light beam spot follow a track of an optical disc. be.

[Prior Art] Conventionally, there are two types of tracking rotating mirror devices of this type, as shown in FIGS. 6 to 9. That is, FIGS. 6 and 7 show a conventional example in which a reflecting mirror is supported by a rubber member, and a mirror holding member 2 that holds a reflecting mirror l is shown in FIG.
One end of a support member 3 made of silicone rubber or the like is bonded and baked on the back surface of the mirror, and is supported by a base 4 via this support member 3, and rotated by a coil 5 attached to the rear of the mirror holding member 2. It has become so.

8 and 9 show a conventional example in which a reflecting mirror 1 is supported by a rotating shaft. 1 The reflecting mirror 1 is attached to a support member 6 having a bearing 6a at one end, and around the rotating shaft 7 inserted through the bearing 6a. The support member 6 is rotatably driven by a driving force acting between a coil 8 attached to the back surface of the support member 6 and a magnetic circuit 9.

[Problems to be Solved by the Invention] Among the conventional examples described above, the former method in which a rubber member is used as the support member 3 has a problem in that the rotation angle changes depending on the current flowing through the drive coil 4 due to hysteresis accompanied by permanent deformation peculiar to the rubber member. However, control becomes complicated due to non-linearity and variations in mechanical properties between lots of the support member 3, and it is difficult to define the neutral position and center of rotation. There are problems in that it is difficult to miniaturize from a molding point of view.

Furthermore, even in the latter method of supporting by a rotating shaft, stick-slip occurs when rotating by a minute angle, resulting in increased nonlinearity and complicated control. Furthermore, a high level of machining accuracy is required to prevent rattling of the bearing 6a, making miniaturization difficult.

SUMMARY OF THE INVENTION An object of the present invention is to provide a rotating mirror device for tracking that eliminates the above-mentioned drawbacks, has a support mechanism that allows easy control of the rotation angle, and can be downsized.

[Means for Solving the Problems] In order to achieve the above-mentioned object, a tracking rotating mirror device according to the present invention includes a tracking rotating mirror device that drives a light beam spot in the radial direction of an optical disk of an information recording medium. This mirror device is characterized in that a mirror holding member that holds a reflecting mirror is rotatably supported by a thin plate spring or a wire.

[Function] The rotating mirror device for tracking having the above configuration has the following features:
By deforming a thin plate spring or wire, a reflecting mirror is rotated to deflect a light beam.

[Example] The present invention will be described in detail based on the example illustrated in FIGS. 1 to 5.

Fig. 1 is a perspective view of an embodiment in which a reflecting mirror is suspended by a thin plate spring, Fig. 2 is a sectional view thereof, Fig. 3 is a perspective view of the driven part, Fig. 4 is a side view, and fb) is a Plan view,
FIG. 5 is a rear view of the thin plate spring. The reflective mirror 10 is held by attaching the back surface of its reflective surface to a mirror holding member 11, and the mirror holding member 11 is suspended and held by a thin plate spring 12. A drive coil 13 is wound around the side surface of the mirror holding member 11, and a yoke 14 and a relay yoke 15 are provided on both sides of the coil 13 so as to sandwich the coil 13. A permanent magnet 16 is placed between the yokes 14 and 15. It is mediated.

As shown in FIG. 5 (cl. This twisting part 1
2c constricts the space between the mounting part 12a and the mounting part 12b to create a bridged state, changes the torsional rigidity by changing the width of the torsion part 12c and the thickness of the thin plate spring 12, and changes the next torsional resonance frequency. It is possible to do so.

The rotation of the reflection mirror IO is performed by the yoke 14, the relay yoke 15,
The two torsion parts 12 of the thin plate spring 12 are driven by a magnetic circuit composed of a magnet 16 and a drive coil 13.
c becomes the center of rotation. The mirror holding member 1 serves as a means for defining the center of rotation of the reflecting mirror 10 and regulating translational movement.
The back side of the mirror attachment part 1 of 1, that is, the attachment part 1 of the thin plate spring 12
A pivot shaft 17 is in contact with the back surface of 2a.

For example, when a current flows through the drive coil 13, a force is generated in a direction perpendicular to the reflective surface of the reflection mirror 10, but this force is restrained by the drive coil 13 via the mirror holding member 11 by the thin plate spring 12. Therefore, the moment force is converted into a moment force centered on the torsion part 12c of the thin plate spring 12, and the reflection mirror 10 rotates around the torsion part 12c as shown by the arrow in FIG. The translational movement of the reflecting mirror 10 due to the force defined by the pivot axis 17 and generated in a direction perpendicular to the reflecting surface of the reflecting mirror 10 can be restricted without applying tension to the thin plate spring 12.

Further, in the above embodiment, the torsion portion 12c is made of a flat plate, but in order to change the moment of inertia of the area, sheet metal press processing such as bending, hollowing, punching, etc. may be performed. May be used. Note that the thin plate spring 12 may be made of a synthetic resin material in addition to stainless steel, phosphor bronze, or beryllium copper.

[Effects of the Invention] As explained above, the rotating mirror device for tracking according to the present invention makes the rotating posture of the reflecting mirror more reliable, is easy to control, and is easy to downsize.

[Brief explanation of the drawing]

Drawings 1 to 5 show an embodiment of a rotating mirror device for tracking according to the present invention, in which Fig. 1 is a perspective view, Fig. 2 is a sectional view, and Fig. 3 is a perspective view of a driven part. Fig. 4(a) is a side view thereof, fbl is a plan view, Fig. 5 is a rear view of the thin plate spring, Fig. 6 is a side view of the first conventional example, Fig. 7 is a sectional view, and Fig. 8 is a side view of the thin plate spring. The figure is a perspective view of the second conventional example, and FIG. 9 is an exploded perspective view. Reference numeral 10 is a reflecting mirror, 11 is a mirror holding member, 12 is a thin plate spring, 13 is a drive coil, 14 is a yoke, 15 is a relay yoke, 16 is a magnet, and 17 is a pivot shaft. Patent applicant: Canon Corporation Figure 1 Figure 2 13゜17131'5 ]] <C1) Figure 3 Figure 4 (b) Figure 5 Figure 6 Figure 7 Figure 8 Figure 9

Claims (1)

[Claims] 1. A rotating mirror device for tracking that drives a light beam spot in the radial direction of an optical disk of an information recording medium, in which a mirror holding member that holds a reflecting mirror is rotatable by a thin plate spring or a wire. A rotating mirror device for tracking, characterized in that it is supported by. 2. The rotating mirror device for tracking according to claim 1, wherein the flat portion of the thin plate spring is superimposed on the reflective surface of the reflective mirror. 3. The rotating mirror for tracking according to claim 1, wherein the thin plate spring is constricted between the attachment part of the reflecting mirror and the attachment part to the thin plate spring support member to form the torsion part for the rotation. Device. 4. The rotating mirror device for tracking according to claim 1, further comprising a pivot shaft that abuts the flat surface of the thin plate spring from the back side and restricts translational movement of the reflecting mirror.