JP3465976B2 - Optical system support device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention supports an optical system for optically recording or reproducing predetermined information on an information recording medium such as an optical disk. And an optical system supporting device. 2. Description of the Related Art Conventionally, in an optical system supporting apparatus of this type, an optical element such as an objective lens is provided with a holding member for holding the objective lens and a holder for holding the objective lens so as to follow the surface deflection or inclination of the optical disk. Focusing and tracking control is performed by a drive system including a plurality of support members such as wire springs that support the holding member movably. By the way, since such a driving system is constituted by a secondary driving system for driving the optical element in two-dimensional directions of up, down, left, and right, primary resonance is efficiently suppressed in order to perform stable and highly accurate control. There is a need. [0003] For example, Japanese Patent Application Laid-Open No. 3-73426 (hereinafter referred to as "prior art") discloses an optical system supporting device for damping the primary resonance by attaching a damping material to a supporting member. I have. As shown in FIG. 9A, the prior art device has a support having one end fixed to a fixing member 15 and the other end fixed to a holding member 3 on which the objective lens 1 is mounted. A member, that is, four leaf springs 14 are provided. The holding member 3 has a focusing coil 2 wound around the outer peripheral surface of the holding member 3 and four tracking coils fixed to the side in the direction of the arrow Y in the drawing so as to be adjacent to the focusing coil 2. 4 are provided. Further, as shown in FIG. 9B, the four leaf springs 14 are provided with first and second fixing portions 27 and 28 near both ends thereof, respectively. First and second positioning holes 16, 17 for fixing the leaf spring 14 to the fixing member 15 and the holding member 3 are formed in the second fixing portions 27, 28. In such a leaf spring 14, the first spring portion 25 formed at the center thereof is provided on the second fixed portion 28 side.
A first protruding portion 26 protruding on both sides of the first spring portion 25 along the direction in which the leaf spring 14 extends; and a first protruding portion 26 provided on the distal end side of the first spring portion 25. A second protrusion 24 protruding perpendicular to the first protrusion 26 is provided. On the other hand, on the first fixed portion 27 side of the leaf spring 14, a support portion 29 formed narrower from the first fixed portion 27 toward the extending direction of the leaf spring 14.
Is provided. The second projection 24 and the support 29
A second spring portion 23 having a predetermined length extends between the first spring portion 25 and substantially the entire leaf spring 14 in the focus direction (arrow Z direction) and the tracking direction. (In the direction of arrow X). According to such a configuration, power is supplied to the focus coil 2 and the tracking coil 4 via the terminal portions 31 protruding from both ends of the leaf spring 14, so that the holding member 3 is moved relative to the fixed member 15. The displacement can be controlled in a predetermined direction. A region from the first and second spring portions 25 and 23 to the first and second protrusions 26 and 24 is covered with a damping material 32. For this reason, the torsional vibration of the leaf spring 14 and the vibration energy of the second spring portion 23 generated during the displacement control of the holding member 3 are suppressed by the damping material 32. However, when the damping material 32 is coated on the supporting member, that is, the four leaf springs 14 as in the prior art, the viscoelasticity of the damping material 32 causes the leaf springs 14 to be covered. However, there is a problem that the spring constant increases. In order to secure a desired spring constant, the length of the leaf spring 14 may be increased. However, in this case, there is a problem that the size of the optical support device increases in proportion to the length of the leaf spring 14. . SUMMARY OF THE INVENTION The present invention has been made in order to solve such a problem, and an object of the present invention is to provide a highly reliable compact optical system supporting apparatus which can obtain a desired damping effect with a simple configuration. To provide. [0015] In order to achieve the above object, the present invention provides an optical head having one end fixed to a holding member for holding an optical element and the other end fixed to a fixing member. Fixed in the first direction, which is the focusing direction.
The holding member moves in a second direction that is a tracking direction.
Optical system supporting device odor comprising a support member for cantilever <br/> support relative to said fixing member to said holding member such movement possible
The support member may be configured to move in the first direction and the second direction.
An elongated member extending in a third direction perpendicular to
When viewed in the first direction, the support member is
Opposite to the side on which the holding member is disposed with respect to the fixing member
The holding member has a U-shaped portion projecting to the side,
It is fixed to the fixing member via a U-shaped part,
Serial U-shaped portion is characterized by being placed in a gel Damping <br/> ring material filled disposed in the filling member. Hereinafter, an optical system supporting apparatus according to a reference example of the present invention will be described with reference to FIGS. As shown in FIGS. 1 to 3, an optical system supporting device of the present reference example,
Holding member 20 holding optical element, ie, objective lens 10
And a supporting member, that is, four springs 30 whose one end fixing portion 30a is fixed to the holding member 20 and the other end fixing portion 30b is fixed to the fixing member 40. The holding member 20 is fixed by the springs 30. It is configured to be displaceably supported. Here, an arrow X direction in the figure indicates a tracking direction, and an arrow Z direction indicates a focus direction. Therefore, the holding member 20 that holds the objective lens 10 applied to the present embodiment is supported by the four springs 30 so as to be displaceable in the focus direction and the tracking direction. In particular, as shown in FIGS. 2 and 3, cutouts 20a are formed at both edges of the holding member 20, and the focus coil 21 and the tracking coil 22 are respectively formed in the cutouts 20a. It is fixed (see FIG. 1). On the inner surfaces of these notches 20a, the protrusions 20 are respectively provided.
The projection 20b is provided so that the mounting position of the focus coil 21 is determined by the projection 20b. The holding member 20 is provided with a balancer 23 that can be adhered along the outer periphery of the bottom surface. The balancer 23 has a recess 23a, and the holding member 20 has a recess 20c. I have. The four springs 30 have fixing portions 30a and 30b formed at both ends thereof attached to the holding member 20 and the fixing member 40, respectively. It has the function of supporting it to be freely displaceable. Specifically, each of the four springs 30 is formed by etching or pressing a thin metal material such as beryllium copper, for example. The other end fixing portion 30 b is fixed to the mounting surface 40 a protruding from both sides of the fixing member 40. In the vicinity of the fixed portions 30a and 30b at both ends of the spring 30, a narrow portion 30c narrow in the X direction in the drawing and a substantially N-shaped bent portion 30d described later (FIGS.
6) is formed, and mainly these constricted portions 30 are formed.
The holding member 20 is configured to be displaced in the X and Z directions by bending the c and the bent portion 30d. The entire bent portion 30d and a part of the other end fixing portion 30b on the bent portion 30d side are covered with a damping material 50 such as butyl rubber. The fixing member 40 has a boss 40e protruding from its bottom surface.
(See FIG. 3). The base 42 is formed by press-molding a single iron plate. The base 42 is integrally formed with an outer yoke 42a and an inner yoke 42b that constitute a magnetic circuit. The magnet 43 is adhered to the inner surface of the. On the base 42, a light emitting diode (LED) 44, a photo detector (PD) 45 for receiving the light emitted from the LED 44, and the holding member 20
And a light blocking member 20f (see FIG. 2) positioned in the optical path between the LED 44 and the PD 45. According to such a configuration, the holding member 20
Is displaced, a part of the light from the LED 44 is blocked by the light blocking member 20f that moves together with the holding member 20. At this time, the remaining light passing through the light shielding member 20f is P
The light is received by D45. The PD 45 outputs an electric signal according to the amount of received light, and based on the electric signal,
The position and the moving speed of the objective lens 10 held by the holding member 20 are detected. LED like this
44 and PD 45 are connected to a flexible printed circuit (FPC) 46 for signal transmission (see FIG. 2),
The FPC 46 is configured to supply a control current to the focus coil 21 and the tracking coil 22. Next, the damping behavior of the optical system supporting device of the present reference example will be described with reference to FIGS. In the optical information recording and reproducing apparatus in which the optical system supporting device is arranged in the present embodiment (not shown), during recording and reproduction of information,
A light beam emitted from an optical system unit (not shown)
After being reflected from the mirror 24 (see FIGS. 2 and 3), the light is condensed on a recording medium surface (not shown) via the objective lens 10 mounted on the holding member 20. In such recording / reproducing, the fixing member 4
When current flows from the connection land 40g (see FIG. 1) provided to the focus coil 21 or the tracking coil 22 via the spring 30, the four springs 30 move due to the vibration of the holding member 20. At this time, the damping material 5
When 0 is deformed based on the viscoelasticity, the primary resonance of the spring 30 is damped. As shown in FIG. 4, such a spring 30 passes through a bending portion 30d from the other end fixing portion 30b, and then connects to the one end fixing portion 30a via the connecting portion 30k and the constricted portion 30c.
It is constituted so that it may extend. A bent portion 30d provided in the vicinity of the other end fixing portion 30b has a first spring portion 30d-1 extending from the other end fixing portion 30b in the direction of the arrow Y in the drawing, and A second spring portion 30d-2 which is bent approximately 180 ° from the first spring portion 30d-1 and extends in the direction of the arrow minus Y in the drawing, and is bent approximately 180 ° from the second spring portion 30d-2. A third spring portion 30d-3 extending in the direction of the arrow plus Y in the figure is provided. First to third spring portions 30d-1, 30d
The widths of -2, 30d-3 and the constricted portion 30c are smaller than the width of the connecting portion 30k so that the spring 30 is easily bent in the directions indicated by arrows X and Z in the drawing. The first
Between the second spring portion 30d-1 and the second spring portion 30d-2,
The gap between the third spring portion 30d-2 and the third spring portion 30d-3 is set small. [0030] Thus, the spring 30 applied to the optical system supporting device of the present reference example, since the bent portion 30d is formed, the second spring portion 30d-2 third spring portion 30d- Three
The effective effective length (effective length) of the spring between the one end fixing portion 30a and the other end fixing portion 30b can be lengthened by the total length of. For this reason, since the stress generated in the spring 30 can be reduced, the reliability of the device can be improved. The damping material 50 allows the entire bent portion 30d and the bent portion 30d of the other end fixed portion 30b to be formed.
The following effects are achieved by covering a part of the side. That is, for example, when the holding member 20 (see FIGS. 1 to 3) is displaced in the direction of the arrow plus Z in the figure, the spring 30 is deformed as shown in FIG.
First to third spring portions 30d-1, 30d-2, 30d
-3 are respectively displaced in the direction of arrow Z and relatively displaced. Specifically, the relative displacement of the first and second spring portions 30d-1 and 30d-2 in the direction of arrow Z, the second and third spring portions 30d-
The relative displacement of the second and third spring portions 30d-2 and 30d-3 in the arrow Z direction between the end of the second and third spring portions 30d-2 and 30d-3 and the other end fixing portion 30b. Relative displacement occurs. However, since the entire bent portion 30d and a part of the other end fixed portion 30b on the bent portion 30d side are connected by the damping material 50, the amount of deformation received by the damping material 50 increases. As a result, the spring 30
, Etc., can be efficiently damped. For example, when the holding member 20 is displaced in the direction of the arrow plus X in the figure, the spring 30 is deformed as shown in FIG. 6, and the bent portion 30d and the constricted portion 30c (see FIG. 4) are formed. Each is deformed and bent in the direction of the arrow X. For this reason,
The distance between the first and second spring portions 30d-1 and 30d-2 and the distance between the second and third spring portions 30d-2 and 30d-3 increase, and the first and second spring portions 30d-2 and 30d-3 increase. Spring part 30d
-1 and 30d-2 arrow minus Y direction end and other end fixing part 3
0b with respect to 0b. However, since the entire bent portion 30d and a part of the other end fixed portion 30b on the bent portion 30d side are connected by the damping material 50, the amount of deformation received by the damping material 50 increases. As a result, the primary resonance and the like of the spring 30 can be efficiently damped. As described above, according to the present embodiment , the bent portion 30d is formed in the spring 30, so that the total length of the second spring portion 30d-2 and the third spring portion 30d-3 is increased. Only, the effective spring length (effective length) between the one end fixing portion 30a and the other end fixing portion 30b can be increased. At the same time, in the case of the present embodiment , the effective length of the spring 30 is increased by bending the spring 30 at the bending portion 30d, so that the distance between the fixed portions 30a and 30b does not increase. That is, even in a state where the distance between the fixed portions 30a and 30b is constant, the provision of the bent portion 30d can ensure a sufficient spring effective length to correspond to a desired spring constant. As a result, the spring 3
It is possible to provide a compact optical system supporting device capable of reducing the stress generated at zero. Further, the spring 30 applied to the present embodiment is
Since the entire bent portion 30d and a part of the other end fixed portion 30b on the bent portion 30d side are connected by the damping material 50, the primary resonance of the spring 30 and the like can be efficiently damped. As a result, it is possible to provide a highly reliable optical system supporting device capable of obtaining a desired damping effect. Next, various modifications of the above-described reference example will be described with reference to FIGS. FIG.
As shown in (A), the spring 3 applied to the first modification example
0 is the first to third spring portions 30d-1 and 3d at the bent portion 30d to further increase the effective spring length.
In addition to Od-2 and 30d-3, fourth and fifth spring portions 30d-4 and 30d-5 are further formed. As shown in FIG. 7B, according to the optical system supporting device applied to the second modification , the bent portion bent in the direction of arrow Z with respect to the extending direction (direction of arrow Y). 30d
Are integrally formed.
And each bending part 30d is simultaneously covered with the damping material 50. The springs 30 applied to the present modification are each formed of a wire having a circular cross section. According to such a configuration, the two springs 30
Are simultaneously configured with one wire, so that the manufacturing cost can be reduced. Further, since the area occupied by the spring 30 can be restricted within the arrow YZ plane, it is possible to prevent the device from expanding in the arrow X direction. Further, the extending direction of the first and second spring portions 30d-1 and 30d-2 constituting the bent portion 30d is set to a direction (arrow Z direction) orthogonal to the extending direction of the spring 30 (arrow Y direction).
, The extension direction of the spring 30 (arrow Y direction)
Vibration can be damped. As shown in FIG. 7 (C), the spring 30 applied to the third modification is formed of a wire having a circular cross section, and the bent portion 30d has a wire-like spring 30.
Is formed by looping. According to such a configuration, the bent portion 30d
Has a configuration in which the spring 30 is simply looped, so that the manufacturing cost of the device can be reduced. FIG.
As shown in (D), the spring 3 applied to the fourth modification example
0 is provided with a pair of bent portions 30d formed in a symmetrical shape on both sides of the spring 30 by forming a U-shaped slit 30f, and each of the bent portions 30d has a first And second spring portions 30d-1 and 30d-2. According to such a configuration, since the spring 30 has a symmetrical shape with respect to the extending direction (Y direction), even if the holding member 20 moves in the arrow X or Z direction (see FIG. 1 to 3), the spring 30 does not twist around the arrow Y axis. As shown in FIG. 7 (E), a rectangular slit 30f is formed in the spring 30 applied to the fifth modified example, so that a pair of symmetrically formed springs 30 are formed on both sides of the spring 30. The first and fourth spring portions 30d-1 and 30d-4 extending in the arrow Y direction, and the first and fourth spring portions 30d-4 extend in the arrow X direction. Second, third, fifth spring portions 30d-2, 30d-3, 30d
-5 is formed. According to such a configuration, even when the holding member 20 moves in the arrow X or Z direction (see FIGS. 1 to 3), the spring 30 does not twist around the arrow Y axis. . [0044] Further, as a variation Katachirei also preferably configured as follows. As the damping material 50, any material can be used as long as it is a viscoelastic material having damping characteristics. For example, fluorine rubber or the like can be applied instead of butyl rubber. A damping material 50 made of a metal plate such as aluminum or a thin sheet made of polyester resin is placed on the double-sided pressure-sensitive adhesive sheet formed of an acrylic polymer.
It may be attached to 0d. Also, acrylic or silicone gels,
The damping material 50 may be formed by applying silicone grease or the like to the bent portion 30d and hardening as necessary.
Further, a filling portion capable of filling the damping material 50 is provided around the bent portion 30d, and the damping material 50 is provided in the filling portion.
And the bent portion 30d may be positioned. In the above-described reference example , the bent portion 30d
Is covered only with the damping material 50, but the invention is not limited to this.
May be coated. According to such a configuration, a high damping effect can be realized. In the above-described reference example , the bent portion 30d
Is formed only on the side of the other end fixing portion 30b. However, a bent portion 30d may be further formed on the side of the one end fixing portion 30a, or one portion may be provided between the two fixing portions 30a and 30b. As described above, the bent portion 30d may be formed. Further, the spring 30 may be formed of a material other than metal, for example, a molded product of plastic or a sheet of polyimide or the like. Further, the optical system support device of the present invention can be applied to a support device that supports the objective lens 10 only in one of the focus direction and the tracking direction, and an optical element other than the objective lens 10, for example, The present invention is also applicable to a supporting device such as a relay lens or a mirror. In the bent portion 30d applied to the above-described reference example , the extending direction of each spring portion is reversed, that is, approximately 180 degrees. It is possible to achieve the same effect. Next, an optical system supporting device according to the real施例of the present invention will be described with reference to FIG. In the description of this embodiment, the same components as those of the reference example are denoted by the same reference numerals, and description thereof will be omitted. As shown in FIG. 8, a filling member 60 is fixed on the surface of the fixing member 40 applied to this embodiment on the side of the arrow minus Y in the figure. On both sides in the X direction, concave filling portions 6 each having a rectangular cross section are provided.
0a is formed. The filling portions 60a are filled with the damping material 50. In this configuration, each of the four springs 30 extending from the one end fixing portion 30a fixed to the mounting surface 20e of the holding member 20 in the direction of the fixing member 40 (the direction of the arrow minus Y in the drawing) is provided. Filling part 60a of the filling member 60
After passing through the inside of the damping material 50 filled in the fixing member 40, the other end fixing portion 30b is fixed to the mounting surface 40a of the fixing member 40. More specifically, the springs 30 extending from the one-end fixing portion 30a in the direction of the arrow minus Y in the drawing each have a U-shaped portion 30e bent approximately 180 ° in the damping material 50 filled in the filling portion 60a. After being formed, the other end fixing portion 30b passes through the U-shaped portion 30e,
It is formed so as to protrude outward from the damping material 50 (that is, in the direction of the mounting surface 40a of the fixing member 40 (plus Y direction)). FIG. 3 shows only the configuration of a pair of springs 30 arranged on the arrow minus Y side in the figure among the four springs 30. According to the present embodiment having such a configuration, the effective length (effective length) of the spring 30 other than the U-shaped portion 30e can be increased, so that the holding member 20 for holding the objective lens 10 is provided. It is possible to reduce the stress generated in the spring 30 when is displaced. As a result, a highly reliable optical system supporting device can be provided. Further, even if the size of the filling portion 60a of the filling member 60 is increased, the filling portion 60a can be configured so as not to interfere with the movable portion such as the holding member 20, so that the filling amount of the damping material 50 can be increased. . After the filling portion 60a is filled with the damping material 50, the filling member 60 can be fixed to the fixing member 40, so that the degree of freedom in the assembly process of the apparatus can be increased. Further, there is no need to penetrate the spring 30 through the filling portion 60a, and the filling portion 60a can be formed in a liquid-tight box shape. Therefore, it is possible to prevent the damping material 50 from flowing out of the filling section 60a. The present invention is not limited to the configuration of the embodiment described above. For example, the filling member 60 may be formed integrally with the fixing member 40. The filling section 60a
May be penetrated in the arrow Y direction in the figure. In this case, the damping material 50 is held in the filling portion 60a by its surface tension. [0059]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view schematically showing a configuration of an optical system support device according to a reference example of the present invention. FIG. 2 is an exploded perspective view of the configuration of an optical system support device according to a reference example of the present invention, as viewed from the arrow plus Z side in the figure. FIG. 3 is an exploded perspective view of the configuration of an optical system support device according to a reference example of the present invention, as viewed from the arrow minus Z side in the figure. FIG. 4 is a perspective view schematically showing a configuration of a spring applied to an optical system support device according to a reference example of the present invention. FIG. 5 is a view schematically showing a configuration of a spring applied to the optical system supporting device according to the reference example of the present invention, and shows a deformed state of the spring when the holding member is displaced in the direction of the arrow plus Z in the figure. FIG. FIG. 6 is a view schematically showing a configuration of a spring applied to the optical system supporting device according to the reference example of the present invention, and shows a deformed state of the spring when the holding member is displaced in the arrow plus X direction in the figure. FIG. FIG. 7A is a diagram schematically showing a configuration of a bent portion of a spring applied to an optical system support device according to a first modification of the reference example , and FIG. Perspective view schematically showing a configuration of a spring applied to an optical system supporting device according to a modification,
(C) is a diagram schematically showing a configuration of a bent portion of a spring applied to an optical system supporting device according to a third modification;
(D) is a diagram schematically showing a configuration of a bent portion of a spring applied to an optical system supporting device according to a fourth modification,
(E) is a figure which shows roughly the structure of the bending part part of the spring applied to the optical-system support apparatus which concerns on a 5th modification. 8 is a perspective view schematically showing the applied spring arrangement in the optical system supporting device according to the real施例of the present invention. 9A is a perspective view schematically showing a configuration of a conventional optical system support device, and FIG. 9B is a diagram schematically showing a configuration of a leaf spring applied to the conventional optical system support device. . [Description of Symbols] 30: spring, 30a: one end fixed portion, 30b: other end fixed portion, 30c: constricted portion, 30d: bent portion, 30k: connecting portion, 30d-1: first spring portion, 30d-2 ... 2nd spring part, 30d-3 ... 3rd spring part.

Claims (1)

(57) [Claim 1] A first member which is fixed to one end of a holding member for holding an optical element and the other end of which is fixed to a fixing member, and is in a focusing direction. Direction and track
The holding member is movable in a second direction which is a king direction.
In the optical system supporting device comprising a support member for cantilever supporting the holding member with respect to the fixed member such, the support member is straight in said second direction and said first direction
An elongated member extending in a third angular direction;
When viewed in the direction of 1, the support member is the fixed portion
On the side opposite to the side where the holding member is located with respect to the material
The holding member has a protruding U-shaped portion,
Fixed to the fixing member via a U-shaped portion,
The shaped portion optical system supporting device, characterized in that it is placed in a gel-like damping material filled disposed in the filling member.