JPH0770082B2 - Optical system drive - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical system driving apparatus used in an optical information recording / reproducing apparatus, and more particularly to an optical system driving apparatus suitable for driving an objective lens of an optical head.

[0002]

2. Description of the Related Art FIG. 5 is a plan view showing an example of a conventional objective lens driving device, and FIG. 6 is a side view thereof. 10 in the figure
Reference numeral 1 denotes an objective lens that converges and irradiates a laser beam on a recording medium, and 102 denotes a bobbin provided with an objective lens 101, a focus coil 103, and tracking coils 104a to 104d. The focus coil 103 receives the current supplied to this coil and the focus magnet 111.
By electromagnetic interaction with the magnetic field formed by
The bobbin 102 is driven in the optical axis direction of the objective lens 101.

Reference numerals 104a to 104d are tracking coils. The coils are arranged and fixed in the lower portion of the focus coil 103 on the outer periphery of the bobbin 102 in equal divisions, and the bobbin 102 is electromagnetically interacted with the current of the coil and the magnetic field formed by the tracking magnet 112.
Is rotated about the axis 110 to displace the objective lens 101 in the tracking direction.

Reference numeral 110 denotes a central bearing portion 101 of the bobbin 102.
It is a shaft that is inserted into a and supports the movement of the bobbin 102 in the vertical direction and the rotation direction. The surface of the shaft 110 is mirror-finished to reduce frictional resistance. 111 and 11
Reference numerals 2 are a focus magnet and a tracking magnet, respectively. The yoke 113 forms a magnetic circuit between the magnet and the yoke, and the focusing and tracking operations of the objective lens 101 are performed.

Reference numeral 107 denotes infrared rays (wavelength 850 to 1100n
m) is an LED (light emitting diode) that emits light. LE
The infrared light shaping spot of D107 is applied to the two-division photo sensor 109, and the movement of the bobbin in the rotating direction is detected by the change in the amount of light received between the two sensors of the two-division sensor. Based on this detection signal, the center of the optical axis of the objective lens of the actuator and the center of the optical axis of the head are prevented from deviating due to disturbance or the like during auto-focus pull-in, auto-tracking trace, or multi-track jump. .

Reference numeral 114 is a lead wire connecting the focus coil 103, the tracking coil 104, the infrared light LED 107 and each control circuit. The focus coil and the tracking coil are connected to the land portion of the dedicated flexible substrate 115 provided on the bobbin side. Also, L
The lead wire connecting the ED 107 is the LED flexible substrate 1
Soldered to the land portion provided on 07B.

[0007]

By the way, in the above-mentioned conventional optical system driving device, the flexible substrate is fixed to the optical system holder for the following reason. That is, when the lead wire of the coil or the lead wire of the light emitting element is directly connected to the terminal on the fixed portion side, since the lead wire is not usually excellent in bending durability, it is accompanied by movement of the optical system holder. As a result, the lead wire may be repeatedly bent, embrittled, and broken into a broken line. Therefore, usually, those lead wires are once gathered on the optical system holder, and then connected to another lead wire having excellent bending durability, and this latter lead wire is connected to the terminal on the fixed part side. is doing. That is, a flexible substrate is provided on the optical holder in order to collect the lead wires of the coil and the light emitting element and connect the lead wires of the coil and the light emitting element to the terminals on the fixed portion side via another lead wire. In this case, the individual lead wires are soldered to the prepared individual flexible boards, and the connection state is obtained via these, so not only the assembly work becomes complicated, but also the assemblability deteriorates and the reliability is improved. There was a problem that it lacked.

In view of the above conventional problems, the present invention has an object to provide an optical system driving device capable of improving the assembly workability and the assembly reliability of the device.

[0009]

An object of the present invention is to provide an optical system holder for holding an objective lens, a base for supporting the optical system holder so as to be movable in at least one direction, and the optical system holder. A plurality of coils fixed to each other, a magnetic field generating means fixed to the base for generating a magnetic field that traverses each of the coils, and the optical system holder is moved by energizing the coils. Optical system drive including a light emitting element attached to the optical system holder for detecting the position of the optical system holder, and a light receiving sensor attached to the base at a position facing the light emitting element The device comprises a single flexible substrate fixed to the optical system holder, on which the terminal of the light emitting element and the terminal of the coil are connected and the light emitting element is mounted. It is achieved by the optical system driving device for.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the following description, an objective lens will be taken as an example of the optical system.

FIG. 1 is a perspective view showing an embodiment of an optical system driving device according to the present invention, and FIG. 2 is an exploded perspective view thereof. In the figure, 1 is an objective lens which converges and irradiates a laser beam on a recording medium, 2 is an objective lens 1 and a focus coil 3,
The bobbin is provided with tracking coils 4a to 4d. The bobbin 2 is supported on the base 15 so as to be rotatable about the shaft 10 and movable in the vertical direction along the shaft 10. The focus coil 3 drives the bobbin 2 in the optical axis direction of the objective lens 1 by electromagnetic interaction between a current supplied to the coil and a magnetic field formed by the focus magnet 11.

4a to 4d are tracking coils,
The bobbin 2 is fixed to the outer periphery of the bobbin 2 under the focus coil 3 in equal divisions, and the bobbin 2 is electromagnetically interacted with the current supplied to the coils 4a to 4d and the magnetic field formed by the tracking magnet 12. Is rotationally displaced about the axis 10 to displace the objective lens 1 in the tracking direction.

Reference numeral 10 denotes a shaft which is inserted into the central bearing portion 1a of the bobbin 2 and supports the displacement of the bobbin 2 in the vertical direction and the rotational direction. The surface of the shaft 10 is mirror-finished to reduce frictional resistance. . Reference numerals 11 and 12 are a focus magnet and a tracking magnet, respectively, and a yoke 13 forms a magnetic circuit between the magnets and the yokes to perform focusing and tracking operations.

An LED (light emitting diode) 7 emits infrared rays (wavelength band 850 to 1100 nm). This L
The ED 7 is attached to the bobbin 2. Reference numeral 9 is a two-divided sensor, which is a flexible substrate 8 for connecting the lead wires 14.
Is mounted on. In this case, the split sensor 9
The terminals of the two-divided sensor 9 are connected to the external circuit by bonding and connecting the electrodes of the chip and the flexible land portion of the flexible substrate 8. Of course, the chip surface is masked for protection. A substrate 8d is fixed to the back side of the flexible substrate 8 to which the two-divided sensor 9 is attached, and is positioned and fixed on the positioning surface of the yoke 13 with the substrate 8b as a reference.

Reference numeral 6 denotes a neutral holding rubber, which is the bobbin 2
Is provided to hold the neutral position. 5
Is a pin for connecting the neutral holding rubber 6 and the bobbin 2. Here, the infrared light emitted from the LED 7 is shaped into the shape of the opening of the slit 7A when passing through the slit 7A, and is irradiated onto the two-divided sensor 9. Then, the displacement amount of the bobbin 2 in the tracking direction is detected based on the detection signal of the two-divided sensor 9.

FIG. 3 is a plan view of the optical system driving device shown in FIG. 1, and FIG. 4 is a side view seen from the arrow direction of FIG. 3 and 4 show in detail how the lead wire 14 is connected to the bobbin 2. Here, the infrared LED flexible land portion 7B on which the LED 7 is mounted is adhered to the side surface portion of the actuator bobbin 2. The infrared LED flexible land portion 7B includes LED lands D from the upper portion of the bobbin,
E, G, focus coil lands F (+), F
(-), Lands for tracking coil T (+), T
The lands are arranged on the same flexible substrate in the order of (-). Each lead wire is soldered to each land. The other end of the infrared LED flexible land portion 7B is connected to the land portion of the flexible substrate 8 of the two-divided sensor 9 on the yoke side.

In the above embodiment, L, which is a light emitting element for a lens position sensor, is provided on the actuator movable portion side.
The ED is provided, and the lands for the focusing coil and the tracking coil, which are also provided on the movable portion side, are provided on the flexible substrate for the LED, but the two-divided sensor which is the light receiving sensor is provided on the movable portion side. In this case, the lands of the focusing coil and the tracking coil may be provided on the flexible substrate for the two-divided sensor.

[0018]

As described above, according to the present invention, the flexible board for connecting the coil terminals and the flexible board for connecting the terminals of the light emitting element are shared. Compared with the configuration having the flexible substrate, the flexible substrate needs to be attached only once to the optical system holder, and the assembling work can be simplified. Further, since the light emitting element is mounted on the flexible substrate, the light emitting element can be attached to the flexible substrate in advance before assembling the optical system driving device, and as a result, the light emitting element can be assembled at the time of assembly. It is not necessary to solder the terminals of to the flexible board,
The assembly work can be prevented from becoming complicated, and the reliability of assembly can be improved.

[Brief description of drawings]

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

FIG. 2 is an exploded perspective view of the optical system driving device of FIG.

3 is a plan view of the optical system driving device of FIG. 1. FIG.

FIG. 4 is a side view of the optical system driving device of FIG.

FIG. 5 is a plan view showing an objective lens driving device of a conventional example.

FIG. 6 is a side view of the objective lens driving device of FIG.

[Explanation of symbols]

 1 Objective Lens 2 Bobbin 3 Focus Coil 4a-4d Tracking Coil 7 LED (Light Emitting Diode) 7B Infrared LED Flexible Land 8 Flexible Substrate 9 2-Division Sensor 11 Focus Magnet 12 Tracking Magnet 14 Lead Wire 15 Base

Claims (1)

[Claims] 1. An optical system holder for holding an objective lens ,
A base for movably supporting the optical system holder in at least one direction, a plurality of coils fixed to the optical system holder, and a magnetic field that traverses each of the coils ,
The magnetic field generating means fixed to the base and the optical system holding body for detecting the position of the optical system holding body when the optical system holding body is moved by energizing the coil are attached. a light emitting element, the optical system driving device and a light receiving sensor attached to the base a position opposed to the light emitting element, before
When the terminal of the light emitting element and the terminal of the coil are connected
Both are mounted on the optical system holder on which the light emitting element is mounted.
An optical system driving device, comprising: a single flexible substrate attached .