JP2988979B2 - Rotating mirror device for tracking - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tracking rotating mirror device used for causing an optical beam spot to follow a track on an optical disk, for example, in an optical head of an optical disk device. .

[Prior Art] Conventionally, this type of rotating mirror device for tracking includes:
In order to rotatably hold the reflection mirror, one end of a rubber member such as silicon is bonded and baked on a mirror holding member to form a supporting member. As shown in FIGS. 8 and 9, a mirror holding member 2 for holding the reflection mirror 1 is provided.
Is supported by a thin plate spring 3 or a wire to drive the reflection mirror 1 by a drive coil 4 and to provide a pivot shaft 5 made of a rigid body for defining the rotation center of the mirror holding member 2. Proposed.

[Problems to be Solved by the Invention] Among the above-mentioned conventional examples, in the former method in which the rubber member is used as the support member, the rotation angle is non-linear with respect to the current flowing through the drive coil due to hysteresis with permanent deformation peculiar to the rubber member. And the mechanical properties of the rubber members are varied between lots, so that the control becomes complicated and it is difficult to define the neutral position and the center of rotation. . Further, the latter type using the pivot shaft 5 generates a frictional force due to a tension and a non-coupling force for pushing the rotation center of the reflection mirror 1 in one direction, so that the resonance frequency is increased and the frequency characteristics are disturbed. It has drawbacks such as inconvenience.

An object of the present invention is to make it possible to restrict the translational movement of the reflecting mirror without applying tension to the thin leaf spring supporting the mirror holding member, to make the turning posture of the reflecting mirror more secure, and to provide the mirror holding member with It is an object of the present invention to provide a tracking rotating mirror device which can increase the tracking frequency band by suppressing the resulting resonance frequency to be low and perform data recording and reproduction at high speed.

[Means for Solving the Problems] To achieve the above object, a tracking turning mirror device according to the present invention is a tracking turning mirror device for driving a light beam spot in a radial direction of an optical disk of an information recording medium. Wherein a mirror holding member for holding the reflection mirror is rotatably supported by a thin plate spring, a flat portion of the thin plate spring is overlapped on the back side of a reflection surface of the reflection mirror, and the thin plate spring is placed on the flat portion. A twisted portion for the rotation is formed by constricting between the attaching portion to the thin leaf spring supporting member, and a tip end of a pivot member is adhered to a back surface of a flat portion of the thin leaf spring, and one end of the pivot member is An elastic member serving as a rotation center is provided in the portion.

Further, the tracking turning mirror device according to the present invention is a tracking turning mirror device for driving a light beam spot in a radial direction of an optical disk of an information recording medium, wherein a mirror holding member for holding a reflection mirror is a thin plate spring. And the flat part of the thin leaf spring is superimposed on the reflecting surface of the reflection mirror, and the thin leaf spring is constricted between the flat part and the mounting part to the thin leaf spring supporting member, thereby turning the flat spring. A twisted portion is formed for movement, the tip of the pivot member is bonded to the back of the flat portion of the thin plate spring, and the tip is formed into a spherical or knife-edge shape by an elastic member.

[Operation] In the tracking turning mirror device having the above-described configuration, the pivot member using an elastic body having a shape with reduced rigidity in the desired turning direction defines the turning center of the reflecting mirror and the thin plate spring. Regulates the translational movement of the reflecting mirror without applying tension to the mirror.

Embodiment The present invention will be described in detail based on an embodiment shown in FIGS.

FIG. 1 is a side view of an embodiment applied to a tracking rotating mirror device of a type in which a reflection mirror is suspended by a thin plate spring, and FIG. 2 is a perspective view thereof. The reflection mirror 10 is held by attaching a mirror holding member 11 to the back surface of the reflection surface. 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 so as to sandwich the coil 13, and a permanent magnet 16 is provided between the yokes 14 and 15. Intervened.

As shown in FIG. 3, the thin plate spring 12 is
Mounting portion 12a, two mounting portions 12b for supporting the thin plate spring 12, and two torsion portions 12c for rotating the reflection mirror 10. The torsion portion 12c is attached to the mounting portion 12a. Part 1
It is possible to change the torsional rigidity by changing the width of the torsion portion 12c and the thickness of the thin plate spring 12, thereby changing the primary torsional resonance frequency. The rotation of the reflection mirror 10 is performed by a magnetic circuit including a yoke 14, a relay yoke 15, and a magnet 16, and a drive coil 13.
And the two torsion parts of the leaf spring 12
12c is the center of rotation.

As a means for defining the center of rotation of the reflection mirror 10 and restricting the translational movement, the back surface of the mirror mounting portion of the mirror holding member 11, that is, the back surface of the mounting portion 12a of the thin plate spring 13, is made of a synthetic resin material such as POM or nylon. A pivot member 17, which is made and has a tip as shown in FIG. 4, is joined as shown in FIG. The pivot member 17 has a tip portion as a flat portion 17a, a portion serving as a rotation center as a hinge portion 17b, and the hinge portion 17b.
The elastic member is made to have a considerable width so that the rigidity of the reflecting mirror 10 in the rotating direction is extremely reduced.

For example, when a current flows through the drive coil 13, a force is generated in a direction perpendicular to the reflection surface of the reflection mirror 10 in FIG. 1, but this force is generated by the drive coil 13 by the thin plate spring 12 via the mirror holding member 11. Since it is constrained, it is converted into a moment force about the torsion portion 12c of the thin plate spring 12, and the reflection mirror 10 rotates around the torsion portion 12c. Reflection mirror 10
The pivot center of is defined by the pivot member 17,
Translational movement of the reflecting mirror 10 due to a force generated in a direction orthogonal to the reflecting surface of the reflecting mirror 10 can be regulated without applying tension to the thin plate spring 12.

The above embodiment is an example in which the rigidity in the desired rotation direction is reduced by using the shape effect. However, as shown in FIGS. 6 and 7, the thin plate spring 12 is interposed with the elastic member 18 as shown in FIGS. The same effect can be obtained by supporting with the rod-shaped pivot shaft 19. Here, the pivot shaft 19 is mounted on the mounting portion 12a of the thin leaf spring 12 via an elastic member 18 such as room temperature vulcanized silicone rubber without applying tension to the mirror holding member 11 or the thin leaf spring 12. In addition, the translation movement of the reflection mirror 10 is regulated. Although the elastic member in this case is spherical, the reflection mirror 10
In order to further ensure the definition of the center of rotation, a knife edge may be used.

[Effect of the Invention] As described above, the tracking turning mirror device according to the present invention can make the turning attitude of the reflecting mirror more reliable and can suppress the torsional resonance frequency caused by the reflecting mirror supporting member to be low. Therefore, the tracking frequency band is expanded, and as a result, data can be recorded and reproduced at a high speed.

[Brief description of the drawings]

1 to 7 show an embodiment of a rotating mirror device for tracking according to the present invention. FIG. 1 is a side view, FIG. 2 is a perspective view, FIG. 3 is a plan view of a thin plate spring, and FIG. 4 is a perspective view of the pivot member, FIG. 5 is a partially cutaway perspective view, FIG. 6 is a front view of the thin plate spring of the second embodiment, and FIG. 7 is a partially cutaway perspective view. FIG. 8 is a perspective view of a conventional example, and FIG. 9 is a plan view partially cut away. Reference numeral 10 is a reflection 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, 17 is a pivot member, 18 is an elastic member, and 19 is a pivot shaft.

Claims (2)

(57) [Claims] 1. A tracking rotating mirror device for driving a light beam spot in a radial direction of an optical disk of an information recording medium, wherein a mirror holding member for holding a reflecting mirror is rotatably supported by a thin plate spring. The flat part of the thin leaf spring is overlapped on the back side of the reflection surface of the reflection mirror, and the thin leaf spring is constricted between the flat part and the mounting part to the thin leaf spring support member to form the twist part for the rotation. Forming
A tracking mirror device for tracking, wherein a tip end of a pivot member is adhered to a back surface of a flat portion of the thin plate spring, and an elastic member serving as a rotation center is provided in a part of the pivot member. 2. A tracking rotating mirror device for driving a light beam spot in a radial direction of an optical disk of an information recording medium, wherein a mirror holding member for holding a reflection mirror is rotatably supported by a thin plate spring. A flat portion of the thin plate spring is superimposed on the reflection surface of the reflection mirror, and the thin plate spring is constricted between the flat portion and a mounting portion to the thin plate spring support member to form a twist portion for the rotation. A tip end of a pivot member is adhered to a back surface of a flat portion of the thin plate spring, and the tip end is formed in a spherical or knife-edge shape by an elastic member.