JPH076923U - Objective lens drive - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an objective lens driving device that prevents the vibration damping effect from decreasing even when the ambient environment is low. [Structure] A circuit pattern 11 that operates as a heat generating portion with respect to an objective lens holder 1 on which an objective lens 2 is mounted.
The sheet body 10 on which the focus drive coil 11 and the tracking drive coil 12 are formed is attached so that the intermediate portion 13 in which a and 12a are formed is brought into contact with the balancer 3 as a vibration damping member.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an objective lens driving device in an optical pickup used in an optical disc device or the like.

[0002]

[Prior art]

 An optical pickup used in an optical disc device or the like has an objective lens driving device for always focusing a light beam emitted from a laser device or the like on a predetermined recording track on the recording surface of the optical disc. The objective lens driving device includes a focus driving coil and a focusing magnet for driving the objective lens in the optical axis direction, and a driving unit for driving the objective lens in a direction orthogonal to the optical axis. It is composed of a tracking driving coil and a tracking magnet drive unit.

FIG. 8 shows a conventional schematic structure of an optical pickup. 1 is an objective lens holder, 2 is an objective lens placed at a position away from the center O of the objective lens holder 1, and 3 is an objective lens holder. The balancer is attached to the objective lens holder 1 at a position opposite to the center O in order to balance the weight of No. 1. A focus drive unit and a tracking drive unit are provided at predetermined positions around the objective lens holder 1. In an optical pickup having such a structure, particularly when controlling the focus direction, the objective lens 2 is integrated with the objective lens holder 1 by the action of the focus magnet when a drive current is passed through the focus drive coil. Since it is driven in the optical axis direction as indicated by the arrow along O, focus control can be performed.

By the way, in performing such focus control, when the objective lens holder 1 is driven, high-order resonance due to bending vibration occurs at a frequency of several KHz or more, and the objective lens 2 vibrates abnormally. However, it is difficult to drive the objective lens 2 accurately. For this reason, conventionally, improvement measures have been proposed as disclosed in Japanese Patent Laid-Open No. 3-144924. As shown in FIG. 6, one of the means is to attach a balancer 3 to the objective lens holder 1 via an adhesive material 4 such as a double-sided adhesive tape, and the action of this adhesive material 4 causes the higher order resonance. The idea is to absorb the vibration caused by. In this case, the balancer 3 functions as a vibration damping member that reduces resonance. Alternatively, as shown in FIG. 7, a counterweight 5 acting as a damping member is attached to the balancer 3 attached to the objective lens holder 1 via the adhesive material 4, and the action of the adhesive material 4 causes higher resonance. There is also an idea to absorb the vibration caused by.

[0005]

[Problems to be solved by the device]

 However, since the pressure-sensitive adhesive material 4 used to absorb the vibration due to higher-order resonance has temperature characteristics in the past, its viscosity changes according to the temperature change of the surrounding environment. There is a problem in that the effect varies, and the viscosity decreases (hardens) especially at low temperatures, and the damping effect decreases.

The present invention has been made to solve the above problems, and provides an objective lens driving device that prevents the damping effect from decreasing even when the ambient environment is low. It is intended.

[0007]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a vibration-damping member for an objective lens holder on which an objective lens is mounted, via an adhesive material so that its mounting surface is parallel to the vibration resonance direction under the control drive of the objective lens. In the objective lens driving device with the attached, a sheet body in which a focusing drive coil and a tracking drive coil are juxtaposed on an insulating sheet, and an intermediate portion where a circuit pattern connecting the two coils is formed is described above. It is characterized in that it is attached to the objective lens holder so as to come into contact with the damping member, and the circuit pattern of the intermediate portion is operated as a heat generating portion.

[0008]

[Action]

 According to the configuration of the present invention as set forth in claim 1, an intermediate portion having a circuit pattern that operates as a heat generating portion is formed on an objective lens holder to which a vibration damping member is attached via an adhesive material. Since the sheet on which the focus drive coil and the tracking drive coil are respectively formed is attached so as to be in contact with, the heat generated in the heat generating portion is transferred to the adhesive material via the vibration damping member. Therefore, even when the ambient environment is low, the adhesive material is warmed by the heat, so that the viscosity is kept large and the vibration damping effect becomes large.

[0009]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. 1 to 4 show an embodiment of an objective lens driving device of the present invention. FIG. 1 is a plan view showing the driving device of this embodiment, FIG. 2 is a side view of FIG. 1, and FIG. 4 is a side view of FIG. 3. FIG. The objective lens holder 1 is supported rotatably around the fixed shaft and movable along the fixed shaft by inserting the shaft hole 7 into the fixed shaft. The objective lens 2 is attached to the objective lens holder 1 with its optical axis parallel to the shaft hole 7. A balancer 3 is attached to the objective lens holder 1 on the opposite side of the objective lens 2 with the shaft hole 7 as a center, with an adhesive material 4 interposed therebetween.

The objective lens holder 1 has sheet holding frames 20 and 20 which are symmetrical with respect to a line connecting the center of the shaft hole 7 and the center of the objective lens 2 and which are concentric with the shaft hole 7 and which are partially cylindrical. On the outer peripheral surfaces of the sheet holding frames 20 and 20, a sheet body 10 having an insulative sheet on which a focus drive coil 11 and a tracking drive coil 12 are juxtaposed is attached. The sheet body 10 has a length from the one sheet holding frame 20 to the other sheet supporting frame 20 through the back surface portion of the balancer 3, and has a cylindrical shape along the partial cylinders of the sheet holding frames 20 and 20. None, the intermediate portion 13 in the length direction of the sheet body 10 is flat along the back surface of the balancer 3, and a circuit for connecting the focus drive coil 11 and the tracking drive coil 12 to the intermediate portion 13 A pattern is formed, and this circuit pattern is configured to operate as a heat generating portion as described later.

Magnets 6, 6 are fixed by yokes 9, 9 on the outer peripheral side of the arc-shaped portion of the sheet body 10 along the arcs of the sheet holding frames 20, 20. The yokes 9, 9 and the magnets 6, 6 are formed in an arc shape concentric with the arc of the sheet body 10, and the inner peripheral surface of the magnets 6, 6 and the outer peripheral surface of the arc-shaped portion of the sheet body 10 have a predetermined gap. Facing each other. The magnet 6 is integrally formed with, for example, a resin binder. The magnet 6 is divided by a gap 8 into a focusing magnet 6a and a tracking magnet 6b. The focusing magnet 6a is magnetized so that the N pole and the S pole are lined up in the axial direction, while the tracking magnet 6b is magnetized in a direction orthogonal to the magnetization direction of the focus magnet 6a. A north pole and a south pole are formed in the circumferential direction. As described above, the magnets 6a and 6b are integrally molded and arranged on a continuous common surface.

The focusing magnet 6 a of each magnet 6 faces the focusing drive coil 11 of the sheet body 10, and the tracking magnet 6 b faces the tracking drive coil 12 of the sheet body 10. The yokes 5, 5 are also arranged on the inner peripheral side of the sheet holding frames 20, 20, and the outer peripheries of the respective yokes 5, 5 are formed in arcs concentric with the arcs of the yokes 20, 20. As will be described later, the intermediate portion 13 of the sheet body 10 is provided with terminals 21a and 22a for connecting the drive coils 11 and 12 to an external circuit.

Next, a specific example of the sheet body 10 having a circuit pattern formed in the intermediate portion 13 for connecting the drive coils 11 and 12 and each one will be described with reference to FIG. The sheet body 10 is formed by stacking, for example, two sheet bodies, and is arranged, for example, corresponding to the sheet body 10 shown in FIG. The tracking drive coil 12 is formed in a spiral shape by etching or plating. The drive coils 11 and the drive coils 12 are connected to each other by circuit patterns 11a and 12a, which are formed on the intermediate portion 13 and are made of a conductive pattern for connection. In this case, each of the circuit patterns 11a and 12a is formed to have a length such that sufficient heat is generated when a drive current is passed through the drive coils 11 and 12. Reference numeral 21a denotes each terminal of the focusing drive coil 11 thus formed on the sheet body 10 and 22a denotes each terminal of the tracking drive coil 12 similarly. The terminals 22a, 23a and 24a, 25a shown in FIG. 1 are terminals for pulling out the drive coils 11, 12 from the seat body 10 to the outside.

In this embodiment, when a drive current is passed through the focus drive coil 11 via the terminal 21a, thrust is generated by the drive current and the magnetic flux in the magnetic circuit including the focus magnet 6a. . This thrust is evenly generated in the focusing drive coils 11 and 11 symmetrically arranged in the shaft hole 7, and the shaft hole 7 of the objective lens holder 1 moves along the fixed axis so that the objective lens 2 moves in the optical axis direction. To move to the focusing operation. When a drive current is passed through the tracking drive coil 12 via the terminal 22a, a thrust is generated by the drive current and the magnetic flux in the equation circuit including the tracking magnet 6b. This thrust is equally generated in the tracking drive coil 12 symmetrically arranged in the shaft hole 7, and the objective lens 2 moves together with the objective lens holder 1 in the direction orthogonal to the optical axis to perform the tracking operation.

In this case, according to the present embodiment, particularly when the focus direction is controlled, the intermediate portion 13 having the circuit patterns 11a and 12a that operate as heat generating portions is damped with respect to the objective lens holder 1. Since the sheet body 10 in which the focus drive coil 11 and the tracking drive coil 12 are formed is attached so as to be in contact with the balancer 3 as a member, the heat generated in each of the circuit patterns 11a and 12a is balanced. It is transmitted to the adhesive material 4 via 3. As a result, even if the ambient environment is low, the adhesive material 4 is warmed by this heat, so that the viscosity can be kept large. Therefore, it is possible to absorb the vibration due to the higher-order resonance by utilizing the action of the adhesive material, so that it is possible to prevent the damping effect from being reduced.

[0016]

[Effect of device]

 As described above, according to the present invention, with respect to the objective lens holder, the focusing drive coil and the tracking drive are arranged so that the intermediate portion where the circuit pattern that operates as the heat generating portion is formed is brought into contact with the damping member. Since the sheet body in which the coils are formed is attached, it is possible to prevent the damping effect from being reduced when controlling the focus direction, especially even when the surrounding environment is low.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of an objective lens driving device of the present invention.

FIG. 2 is a side view of FIG.

FIG. 3 is a plan view showing a main part of FIG.

FIG. 4 is a side view of FIG.

FIG. 5 is a plan view showing a sheet body on which a focus drive coil and a tracking drive coil used in the drive apparatus of this embodiment are formed.

FIG. 6 is a cross-sectional view showing a conventional example.

FIG. 7 is a side view showing another conventional example.

FIG. 8 is a schematic view showing an objective lens holder on which an objective lens is mounted.

[Explanation of symbols]

 1 Objective Lens Holder 2 Objective Lens 3 Balancer (Vibration Suppressing Member) 4 Adhesive Material 6a Focus Magnet 6b Tracking Magnet 10 Sheet Body 11a, 12a Circuit Pattern (Heating Section) 11 Focus Drive Coil 12 Tracking Drive Coil 13 Sheet Body Middle part of 20 seat holding frame

Claims (1)

[Scope of utility model registration request] 1. An objective lens driving device in which a vibration damping member is attached to an objective lens holder on which an objective lens is mounted via an adhesive so that its attachment surface is parallel to the vibration resonance direction due to control driving of the objective lens. In the above, a sheet body in which a focus drive coil and a tracking drive coil are juxtaposed on an insulating sheet is provided, and an intermediate portion where a circuit pattern connecting the both coils is formed is brought into contact with the damping member. An objective lens driving device, wherein the objective lens driving device is attached to the objective lens holder, and the circuit pattern of the intermediate portion is operated as a heat generating portion.