JPS63112830A - Optical system driving device - Google Patents

Abstract

PURPOSE:To make it unnecessary to provide a reinforcing member and a screw, and to make the titled device small in size and light in weight, by constituting said device so that a connection of a neutral holding means and a movable member and/or a fixing member can be executed by a fitting attachment of a projecting part and a recessed part fitted to this projecting part. CONSTITUTION:On the side face part of both sides of a movable member 58, total four pairs of supporting pins 68 in which one pair consists of two pieces are provided projectingly and fixed in the horizontal direction, and provided in order to attach neutral holding rubber 70. Two pieces of neutral holding rubber 70 are provided, rubber fitting holes 72, 74 are provided on each of them, the supporting pins 68 provided on the movable member 58 are fitted into the fitting hole 72, and pins 48a, 48b provided on outer yokes 44a, 44b are fitted into the rubber fitting hole 74. In such a way, the movable member 58 is held in a desired neutral position. In such a way, a reinforcing member and a screw are not required in order to provide a neutral holding member, and the whole device can be made small in size and light in weight easily.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical system drive device that is suitably used, for example, to drive an objective lens of an optical head in an optical information recording/reproducing device.

[Prior Art] Conventionally, there has been an optical type in which a laser beam is irradiated in a spot on the surface of an information recording medium to record information on the recording medium and/or to reproduce information recorded on the recording medium. An information recording/reproducing device has been put into practical use.

An example of such a device is an optical disk device. An optical disc, which is a recording medium on which information is reproduced by this optical disc device, has a width of about 1 to 2 pm and a length of 1 to 2 pm.
An information track consisting of a row of information pits of about 3 gm is formed in a spiral shape or a concentric circle shape. When reproducing information recorded as the information bit string, the information track of the optical disk is irradiated with a laser beam in the form of a minute spot from an optical head while the optical disk is rotated, and the information pit string is scanned by the beam spot. When the reflected light or the transmitted light of the light irradiated onto the optical disk surface is detected by a photodetector in this way, the likelihood of the light incident on the photodetector is determined depending on whether or not there is an information spot at the beam spot position. Optical properties change. In this way, a reproduced signal corresponding to the information pit string can be obtained.

In addition, in such an optical disk device, it is extremely important that the minute spot always accurately scan the information pit row on the recording medium. To this end, it is necessary to use autofocusing to correct focal shifts caused by warpage of the recording medium, and autotracking to correct irradiation position shifts caused by eccentricity of the recording medium. As a method to realize this autofocusing function and autotracking function,
Conventionally, an objective lens driving device as shown in FIG. 2 has been considered. Incidentally, FIG. 2 is a perspective view showing a conventional objective lens driving device. Further, FIG. 3 is a plan view of a neutral holding member provided in the objective lens driving device.

As shown in FIG. 2, the conventional objective lens driving device 2 has a base 4 made of a rectangular plate. An arc-shaped permanent magnet 6 is mounted on the base.
A and 6b are provided so as to face each other. Each permanent magnet 6
Outer yokes 8a and 8b are attached to the -L ends of a and 6b, respectively.
is fixed.

Further, at the upper ends of the outer yokes 8a and 8b, as shown in FIG. 2, there is a neutral holding member 10 having a planar or rectangular shape and made of an elastic body, or the longer one of the holding member lO. The reinforcing members 12a and 12b provided on opposite sides are connected to the screws 14.
The installation is fixed by tightening it. Two adhesion members 16 are provided on opposite shorter sides of the neutral holding member 10 so as to face each other. The adhesive member 16 has an objective lens 18 and a weight 20.

A movable member 22 is attached. A cylindrical focusing coil 24 is attached to the lower end of the movable member 22, and rectangular tracking coils 26 (for example, four) are attached on the outer periphery of the coil 24.

A bearing 28 is disposed at the center of the movable member 22, and the weight is balanced in a horizontal direction around the bearing. A shaft 30 fitted into the bearing 28 is fixed to the base 4. The movable member 22 is supported by the shaft so as to be slidable and rotatable on the shaft 30.

Further, an inner yoke (not shown) is integrally formed on the base 4 at a position near the inner circumference of the focusing coil 24. The base 4, the permanent magnet 6a, and the yoke 8a
One magnetic circuit is formed by the and inner yoke, while another magnetic circuit is formed by the base 4, the permanent magnet 6b, the outer yoke 8b, and the inner yoke. By causing the focusing coil 24 and the tracking coil 26 to flow in the magnetic field formed by the magnetic circuit, the movable member 22 can slide and rotate on the shaft 30.

Further, in the above description, the shape of the neutral holding member 1O has a planar two-dimensional shape as shown in FIG. 3, and is formed by punching or molding a silicone rubber plate or the like.

[Problems to be Solved by the Invention] However, since the above-mentioned objective lens driving device requires reinforcing members and screws to provide the neutral holding member, it is difficult to reduce the weight and size of the entire device. there were. Furthermore, when assembling the device, there is a problem in that the work of tightening the reinforcing member with screws is complicated.

[Objective] The present invention has been made in view of the problems of the prior art described above, and its object is to provide an optical system drive device that is small, lightweight, and easy to assemble.

[Means for Solving the Problems] According to the present invention, the above object comprises: an optical system; a movable member provided with one means for holding the optical system and moving the optical system; In an optical system drive device having a fixed member provided with the other means for moving the optical system: the movable member and the fixed member are made of an elastic body that supports the movable member at a desired neutral position. connected by a neutral holding means, and the connection between the neutral holding means and the movable member and/or the fixed member is made by fitting into a convex portion and a concave portion that fits into the convex portion; This is achieved by an optical system drive.

[Example] Hereinafter, an example according to the present invention will be described specifically and in detail based on the drawings.

Note that this embodiment will be explained using an objective lens as an example of the optical system.

FIG. 1 is an exploded perspective view showing an embodiment of the optical system driving device according to the present invention.

As illustrated, the optical system driving device 40 according to the present invention has a substantially rectangular base 42. As shown in FIG. As shown in the figure, arc-shaped outer yokes 44a and 44b are fixed to a pair of opposing sides of the base. Furthermore, permanent magnets 46a and 46b are provided on the surfaces of the outer yokes 44a and 44b that face each other, respectively.
Or it is fixed. Further, two support pins 48a and 48b are fixedly protruding from the upper portions of the outer yokes 44a and 44b, respectively. The support pin is provided to fit a neutrality holding rubber, which will be described later.

Further, a limiter 5 is installed at one end of the outer yokes 44a and 44b.
0a and 50b are fixed in a protruding manner. The limiter is provided to limit the amount of rotation of the movable member in the horizontal direction, which will be described later.

Further, as shown in the figure, a cylindrical support shaft 52 is fixed and protrudes from the center of the base 42. A cylindrical inner yoke 54 is provided around the support shaft.

Further, the optical system driving device 40 of the present invention has a movable member 58 provided with a bearing 56 corresponding to the support shaft 52 described above.

The movable member is provided so as to be rotatable and slidable on the aforementioned support shaft 52. Further, a focusing coil 60 is fixed to the lower end of the movable member 58, and a plurality of rectangular tracking coils 62 (four in the figure) are fixed on the outer periphery of the coil.

Further, as shown in the figure, an objective lens 64 and a weight 66 are provided on both sides of the movable member 58 with the bearing 56 in between. The objective lens 64 is made of glass or molded resin such as polycarbonate. The weight 66 is provided to keep the center of gravity of the movable member 58 at an appropriate position.

Further, as shown in the figure, on both side surfaces of the movable member 58,
Support pins 68 of a total of 8 trees, 4 sets each consisting of 2 trees, are fixed and protruding in the horizontal direction.

The support pin 68 is provided to attach a neutral holding rubber 70 for holding the movable member 58 at a desired center position. There are two neutral holding rubbers 70, each of which is provided with rubber fitting tags 72 and 74. A support pin 68 provided on the Of moving member 58 is fitted into the rubber fitting hole 72, and an outer yoke 44a is fitted into the rubber fitting hole 74.

Pins 48a and 48b provided on 44b are fitted.

In this way, the movable member 58 is held in the desired neutral position.

In this embodiment, two magnetic circuits are formed, one
One consists of an inner yoke 54, a base 42, an outer yoke 44a, and a permanent magnet 46a, and the magnetic flux is directed to the permanent magnet 46a.
The water flows from the direction toward the inner yoke 54. The remaining magnetic circuit is composed of the inner yoke 54, the base 42, the outer yoke 44b, and the permanent magnet 46b, and the magnetic flux flows from the permanent magnet 46b toward the inner yoke 54.

The inner yoke 54 and the permanent magnet 46a, and the inner yoke 54
The movable member 5 is placed in the gap between the movable member 5 and the permanent magnet 46b.
A focusing coil 60 and a tracking coil 62 are located at the bottom of the 8.
By controlling the current flowing through the movable member 58, the movable member 58 is driven to slide downward in the L direction and rotated in the left-right direction.

Furthermore, the movable member 58 of this embodiment has a shape that is symmetrical on both sides with respect to a plane (y-z plane) that includes the central axis of the bearing 56 and the optical axis (Z direction) of the objective lens 64. The width is narrow in the direction perpendicular to this plane (ie, the X direction). Furthermore, the movable member 58 includes a central axis of the bearing 56.
With respect to a plane (X-2 plane) perpendicular to the plane including the optical axis of the objective lens 64 in the longitudinal direction, it has an asymmetrical shape in the front and rear (Z direction) as shown in a and b in the figure. There is. (Because a#b.) However, the movable member 58 of this embodiment is structurally mechanically sensitive to the weight and position of the objective lens 64 and the weight 66, the hollow shape of the movable member 58, and the various coils. Due to the arrangement, the weight and moment of inertia are balanced around the bearing 56 (0 point), so even if the movable member 58 is slid up and down or rotated left and right, no strange vibrational behavior will occur. It is structured like this.

In addition, the shape of the neutral holding rubber 70 has a three-dimensional structure that allows for a long stroke in the vertical and horizontal directions as shown in the figure, so although it is small and lightweight, it does not have an adverse effect when driving the movable member 58. Never.

Furthermore, the optical system driving device of the present invention positions two neutral holding rubbers 70 on the left and right side surfaces of the movable member 58 at symmetrical positions with respect to the center of the bearing 56 and plane symmetrical with respect to the y-z plane. The movable member 58 and the neutral holding rubber 70 are connected by fitting four rubber fitting holes 72 provided in each of the neutral holding rubbers 70 with support pins 68 provided on the movable member 58. The neutral holding rubber 70 is provided with two rubber fitting holes 74 at the center lip, and the chain holes 74 are provided with two support pins 48a at the -L portions of the outer yokes 44a and 44b. It is positioned and fixed by fitting with 48b.

The optical system drive device assembled as described above is easy to assemble because the neutral holding member is connected and fixed by adhesive, baking, etc.

Further, in the above embodiment, the movable member 58 and the outer yoke 44a,
Although a support pin is provided on the 44b side, the present invention is not limited thereto; a support pin or a pin-shaped protrusion is provided on the neutral holding member side, and a fitting hole is provided on the movable member and the yoke side. An embodiment may also be used in which a Also, a support pin or a pin-shaped protrusion is provided on either the movable member side or the yoke of the neutral holding member, and a fitting hole is provided on the other side, and the support pin is provided on either the movable member or the yoke side on the other side. An embodiment in which fitting holes are provided and fittings are made may also be used.

[Effects of the Invention] As described above in detail and specifically, the present invention enables the connection between the neutral holding means and the movable member and/or the fixed member by fitting the convex portion and the concave portion into which the convex portion fits. This is the optical system drive device that has been developed.

The reinforcing members and screws used in the prior art are no longer necessary, and the device can be made smaller and lighter. Furthermore, assembly of the device becomes easier.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing an embodiment of an optical system driving device according to the present invention, FIG. 2 is a perspective view showing a conventional objective lens driving device, and FIG. 3 is a perspective view showing an example of an optical system driving device according to the present invention. FIG. 3 is a plan view of the neutral holding member. 40... Optical system drive device 58... Movable member 64... Objective lenses 48a, 48b and 68... Support pin 70... Neutral holding rubber

Claims (1)

[Claims] (1) A movable member provided with an optical system, one means for holding the optical system and moving the optical system, and a fixed member provided with the other means for moving the optical system. The movable member and the fixed member are connected by neutral holding means made of an elastic body that supports the movable member at a desired neutral position, and the neutral holding means and the movable member and/or an optical system drive device, characterized in that the connection with the fixing member is made by fitting into a convex portion and a concave portion that fits into the convex portion.