JPH0555308U - Tilt adjustment mechanism for objective lens drive - Google Patents

Abstract

(57) [Summary] [Structure] When the actuator base 21 mounted on the objective lens holder 25 is fixed to the optical block 11 by adjusting the tilt, the actuator base 21 is fixed by a screw 55a at one fixation point, The adjustment screw holes 17 and 17 are provided as the adjustment points, and the L-shaped leaf spring 71 extending between the adjustment point, the fixed point, and the adjustment point is arranged on the back surface of the optical block 11, and the two adjustment screws 65 and 65 are provided. The tilt is adjusted by screwing into the adjusting screw holes 17, 17 and utilizing the reaction force of the L-shaped leaf spring 71. [Effect] With a simple configuration, the tilt of the optical axis of the objective lens 27 can be adjusted and fixed at the same time, the workability is good, there is no problem of positional displacement after adjustment, and rattling due to screw backlash can be prevented.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to an objective lens driving device (actuator) of an optical head that optically reads and writes information by irradiating an optical recording medium such as an optical disk or a magneto-optical disk with a light spot. The present invention relates to a mechanism for adjusting the tilt of the optical axis of an objective lens.

[0002]

[Prior Art]

 When recording / reproducing an optical recording medium, it is necessary to accurately irradiate a target recording track with an optical spot.

Therefore, in conventional optical recording (including magneto-optical recording), the optical head is driven at high-speed coarse access to move the objective lens to a target recording track, and then the focusing coil and the tracking coil are moved. The objective lens actuator is used to finely control the irradiation position of the light spot.

However, since the size of the recording track is extremely fine, if the optical axis of the objective lens is tilted from the regular position, reliable control becomes difficult. Therefore, when incorporating the objective lens actuator into the optical head, it is necessary to correctly adjust the optical axis of the objective lens.

Conventionally, as a tilt adjusting mechanism for such an objective lens actuator, a tilt of the actuator base with respect to the optical block is adjusted with a hollow insect screw, and then the screw is passed through the hollow portion of the hollow insect screw to connect the optical block and the actuator base. Has been reported to be fixed (Japanese Patent Laid-Open No. 63-149839).

However, in this adjusting method, the inclination is adjusted with the hollow insect screw, and then the screw is further tightened, so that it is troublesome twice and the workability is poor. In addition, there is a risk that the position of the actuator base will shift between the screw adjustment and the tilt adjustment.

[0007]

[Problems to be solved by the device]

 The present invention provides an inclination adjusting mechanism that is easy to adjust and has excellent workability and that can be fixed at the same time when adjusting the inclination.

[0008]

[Means for Solving the Problems]

 The tilt adjusting mechanism of the objective lens driving device of the present invention drives the mounted objective lens to control the irradiation position of the light spot by the objective lens and irradiates the recording medium with the light spot to record or reproduce information. In the tilt adjusting mechanism of the objective lens driving device, the objective lens driving device is fixed, and the actuator base having two adjusting through holes provided on both sides through the objective lens driving device and the actuator base are fixed. An optical block that has a fixing point and two adjustment screw holes that correspond to the adjustment through holes, and two adjustment screws that are fixed to the optical block surface on the opposite side where the actuator base is fixed. It receives the biasing force of the leaf spring by inserting the roughly L-shaped leaf spring arranged to extend between the hole and the fixing point, the through hole for adjustment and the screw hole for adjustment. And an inclination adjusting screw member for holding the actuator base against the optical block and adjusting and fixing the inclination of the actuator base with respect to the optical block.

[0009]

【Example】

 FIG. 1 is an exploded perspective view showing an embodiment of an inclination adjusting mechanism of an objective lens driving device (actuator) of the present invention. FIG. 2 is also a plan view (however, fixing screws and adjusting screws are not shown).

FIG. 3 is a cross-sectional view taken along the line AA of FIG. FIG. 4 is an explanatory diagram showing backlash.

An actuator base 21 is fixed to the optical head base 11 by adjusting its inclination, and a sliding rotation shaft 23 is fixed to the actuator base 21. The objective lens holder 25 is mounted on the sliding rotation shaft 23 so as to be slidable up and down with respect to the sliding rotation shaft 23 via a bearing 33 thereof, and rotatable around the sliding rotation shaft 23. Has been done. An objective lens 27 is mounted on the objective lens holder 25 at a position eccentric with respect to the slide rotation shaft 23, and when the objective lens holder 25 rotates, the objective lens 27 is converged by the objective lens 27 and recorded on the recording disk. The spot irradiation position of the image-forming light flux moves in the tracking direction Tr.

A focusing coil 29 is wound around the outer peripheral surface of the peripheral wall portion of the objective lens holder 25. A magnetic device including a yoke member 39 including an inner yoke 39b and an outer yoke 39a and a magnet 37 is fixed to the actuator base 21. The magnetic flux from this magnetic device crosses the focusing coil 29 to form a linear motor, and when a signal current is passed through the focusing coil 29, the objective lens holder 25 slides up and down along the sliding rotation shaft 23. The focus is controlled.

Further, the four wound tracking coils 31 are fixed to the outer peripheral surface of the peripheral wall portion of the objective lens holder 25. The magnetic flux from the above-mentioned magnetic device intersects with one winding portion of the tracking coil 31 running in the vertical direction to form a rotary motor. By passing a signal current through the tracking coil 31, the objective lens holder 25 Tracking control is performed by rotating around the slide rotation shaft 23. The light beam from the laser diode is reflected by a reflection mirror fixed to the lower side of the optical head base 11 and is launched, passes through the light beam through hole 13 of the actuator base 21, enters the objective lens 27, and is converged. Then, spot irradiation is performed on the recording disk.

The present invention provides a mechanism for adjusting the optical axis of the objective lens 27 to a normal position when the optical head is assembled. Specifically, the tilt of the actuator base 21 for fixing the objective lens holder 25, on which the objective lens 27 is mounted, with respect to the optical head base 11 is adjusted.

An L-shaped leaf spring 71 is fixed to the lower surface side of the optical head base 11 by leaf spring fixing screws 77, 77, 77. The L-shaped leaf spring 71 passes under the opening position of the one adjusting screw hole 17, passes under the fixing screw hole 15a (fixing point), bends here, and then the other adjusting screw hole It extends to 17 openings.

The optical head base (optical block) 11 has two adjusting screw holes 17, 17 penetrating therethrough and opening on the L-shaped leaf spring 71, and fixing screw layers 15 a, 15 b (see FIG. Is not provided). The fixing screw hole 15a is provided so as to substantially correspond to the bent portion of the L-shaped leaf spring 71. The fixing screw hole 15b may be omitted.

The actuator base 21 has two adjusting through holes 61 and 61 and fixing through holes 51 and 51 (one of which is one at positions corresponding to the screw holes 17, 17, 15, 15 of the optical head base 11). (Not shown in the figure) is drilled.

When assembling the actuator base 21 into the optical head base 11, the actuator base 21 is placed on the optical head base 11 to which the L-shaped leaf spring 71 is fixed, and the actuator base 21 is fixed by the fixing screw 55a. 11 is fixed, and the inclinations in the θx and θy directions (see FIG. 1) can be simultaneously adjusted by the two adjusting screws 65 and 65 (adjusting screw members) with the fixed point as a fulcrum.

At this time, since the fixing screw 55a is directly above the L-shaped leaf spring 71, a screw shorter than the sum of the thickness of the actuator base 21 and the optical head base 11 is used (the fixing screw 55a Does not hit the L-shaped leaf spring 71).

On the other hand, as shown in FIG. 3, as the adjusting screws 65, 65, screws longer than (thickness of the actuator base 21) + (thickness of the optical head base 11) are used, and the L-shaped plate is used. The spring 71 is bent so as to be pushed away and tightened so as to receive a reaction force (biasing force, restoring force) from the L-shaped leaf spring 71. The inclinations in the θx direction and the θy direction are adjusted by the difference between the tightening torques of the two adjusting screws 65, 65. Further, as shown in FIG. 4, there is a backlash (play between screws) between the adjusting screw 65 and the adjusting screw hole 17, which causes rattling if no measures are taken. In the adjusting mechanism shown in FIG. 3, the adjusting screw 65 is urged upward by the restoring force of the L-shaped leaf spring 71, so that there is no rattling and no displacement due to backlash occurs.

After the tilt adjustment is completed, if necessary, the fixing screw 55b is tightened to fix the remaining one corner.

[0022]

[Effect of the device]

 According to the present invention, two adjusting screws and an L-shaped leaf spring are used, and the tilt of the lens optical axis of the objective lens driving device is adjusted while the L-shaped leaf spring is bent, and the configuration is simple and easy. Can be adjusted at the same time, and can be fixed at the same time while adjusting the inclination, workability is good, and there is no problem of misalignment after adjustment. Further, the L-shaped leaf spring can prevent the rattling due to the backlash of the screw, so that the tilt can be surely adjusted.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of the present invention.

FIG. 2 is a plan view showing an embodiment of the present invention.

3 is a partially enlarged cross-sectional view taken along the line AA of FIG.

FIG. 4 is an explanatory diagram of backlash.

[Explanation of Codes] 11 Optical Head Base (Optical Block) 13 Luminous Beam Through Holes 15a, 15b Fixing Screw Hole 17 Adjustment Screw Hole 21 Actuator Base 23 Sliding Rotation Axis 25 Objective Lens Holder 27 Objective Lens 29 Focusing Coil 31 Tracking Coil 33 Bearing 35 Balancer 37 Magnet 39 Yoke member 39a Outer yoke 39b Inner yoke 51a Fixing through hole 53a Washers 55a, 55b Fixing screw 61 Adjusting through hole 63 Washer 65 Adjusting screw 71 L-shaped leaf spring 73 Leaf spring through hole 75 washer 77 leaf spring fixing screw 81 backlash

Claims (1)

[Scope of utility model registration request] 1. A tilt adjusting mechanism of an objective lens driving device for driving an mounted objective lens to control an irradiation position of a light spot by the objective lens and irradiating the recording medium with the light spot to record or reproduce information. In, the objective lens driving device is fixed, the actuator base having two through holes for adjustment provided on both sides through the objective lens driving device, and the fixing point to which the actuator base is fixed, And an optical block having two adjusting screw holes penetrating therethrough and fixed to the optical block surface on the opposite side to which the actuator base is fixed, and arranged so as to extend between the two adjusting screw holes and the fixing points. Through the adjusted L-shaped leaf spring, the adjustment through hole and the adjustment screw hole, and actuate the optical block by receiving the biasing force of the leaf spring. Holding a database, the inclination adjustment mechanism of the objective lens driving device, characterized in that it comprises a tilt adjusting screw member for fixing by adjusting the actuator base of the slope with respect to the optical block.