JPH11232673A - Lens position adjusting structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens position adjusting structure in which a lens is manually moved and adjusted to a reference position at which light beams passed through the lens are allowed to be focused at a predetermined position, e.g. on a surface of an optical recording medium, and then the lens is allowed to be held at that position. SOLUTION: A structure includes: a focus control mechanism for automatically adjusting a position of a lens which focuses light beams for performing recording or reproducing information on/from an optical recording medium; and a lens holder supporting mechanism for supporting a lens holder to which the lens is fixed by a supporting member 3 having spring characteristics. The lens holder supporting mechanism has: guiding means 30 for guiding the supporting member 3 along a direction of an optical axis; and moving and holding means 40 for moving and then holding the supporting member 3 at a predetermined position, and is configured so as to adjust a position of the lens.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens position adjusting structure. For example, an optical disc apparatus that records or reproduces information on an optical recording medium by a light beam includes an optical head, and a focus control mechanism incorporated in the optical head uses a lens, such that the light beam focuses on the optical recording medium surface. That is, the objective lens is moved perpendicularly to the optical recording medium surface, and the focal length is automatically adjusted.

However, if the distance between the surface of the optical recording medium and the objective lens is largely deviated from a reference value (focal length), the focus of the objective lens is controlled, so that the objective lens is tilted. There is a demand for a structure in which the beam is held at a reference position where the beam is focused on the optical recording medium surface, and thereafter the focus can be automatically controlled.

[0003]

2. Description of the Related Art A condensed light beam after an objective lens is applied to a recording surface of an optical recording medium (optical disk). The light beam is constantly applied to the optical head during operation of the optical head. A lens holder support mechanism that supports a lens holder to which an objective lens is fixed by a support member so as to focus on a surface, and a focus control mechanism that automatically adjusts the position of the objective lens are provided.

[0005] As shown in FIG. 5, the lens holder support mechanism includes a support member mounting body 4 and a support member 3. The support member mounting body 4 is attached to the base end of each of the four support members 3 having a spring property, such as a spring plate or a spring wire, in the up-down direction and the front and back directions on the paper surface. Is attached to the lens holder 2, so that the lens holder 2 to which the objective lens 1 is fixed is suspended by the support member 3 in a cantilever manner so as to be able to float.

The focus control mechanism includes an objective lens 1, a lens holder 2, coils 5a and 5b, and an N-pole permanent magnet 6a.
And an S-pole permanent magnet 6b. The objective lens 1 is fixed to the center of the lens holder 2, and coils 5 a and 5 b are wound around opposing positions on the side surface of the lens holder 2, and there is a gap at a position where the coils 5 a and 5 b face each other. The N-pole permanent magnet 6a and the S-pole permanent magnet 6b are fixed to a magnet mounting portion (not shown).

The lens holder 2 moves up and down when the support member 3 is displaced (curved) by a spring in the up and down direction.
And the distance of the recording surface of the upper optical disk (not shown) changes.
Now, when a current as shown in the drawing is applied to the coils 5a and 5b, a downward electromagnetic force is generated, and the lens holder 2 moves downward. Also, when a reverse current is applied to the coils 5a and 5b, an upward electromagnetic force is generated, and the lens holder 2 moves upward.

The vertical movement of the lens holder 2 is automatically adjusted by detecting a part of the reflected light of the light beam from the recording surface of the optical disk and performing feedback control to change the amount of current flowing through the coils 5a and 5b. Thus, focus control of the objective lens 1 is performed.

Although not shown, a tracking control mechanism for moving and adjusting the objective lens in the horizontal direction, that is, in the radial direction of the optical disk, is similarly provided.

[0009]

However, according to such a focus control structure, when the focus control mechanism is assembled to the lens holder support mechanism, the support member for supporting the lens holder (objective lens) is in a free state. If the distance between the recording surface of the optical disc and the objective lens is set close to the reference value (focal length), the curvature (spring displacement) of the support member is small even if focus control is performed, and the objective lens is located on the recording surface of the optical disc. On the other hand, if focus control is performed on an objective lens that is hardly tilted but deviates greatly from the reference value (focal length), the curvature of the support member increases, and the lens holder held by the support member tilts. It will be greatly inclined to the surface.

Therefore, there is a problem that the light beam does not impinge perpendicularly on the recording surface of the optical disk, the spot diameter of the light beam becomes elliptical, the optical recording (or reproduction) characteristics are deteriorated, and the device cannot be used.

In view of the above problems, the present invention provides a lens which can be manually moved and adjusted to a predetermined position, for example, a reference position where a light beam passing through a lens focuses on the optical recording medium surface, and then held at that position. It is an object of the present invention to provide a position adjusting structure.

[0012]

In order to achieve the above object, in a lens position adjusting structure according to the present invention, the position of a lens for focusing a light beam for recording or reproducing information on an optical recording medium is automatically adjusted. A focus control mechanism, and a lens holder support mechanism that supports a lens holder to which the lens is fixed by a support member having spring properties;
The lens holder support mechanism includes guide means for guiding the support member along the optical axis direction, and movement holding means for moving the support member and holding the support member at a predetermined position, and adjusts the position of the lens. To be configured.

With this configuration, when the lens holder is supported by the lens holder support mechanism, the lens holder is guided by the moving holding means along the guide means in the optical axis direction (focus adjustment direction), and The lens (objective lens) fixed to the lens can be manually moved and adjusted to a predetermined position, that is, a reference position where the light beam is focused on the optical recording medium surface, and the lens can be held at that position. Can be reduced by the focus control described above, and the amount of spring displacement of the support member due to excessive movement adjustment of the lens can be reduced to minimize the inclination of the lens with respect to the optical recording medium surface.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the gist of the present invention will be described in detail based on a plurality of embodiments shown in the drawings. Note that the same reference numerals are used for the parts described in the conventional drawings, and the same parts are denoted by the same reference numerals throughout the drawings, and redundant description is omitted.

FIG. 1 shows a first embodiment according to the present invention. In the first embodiment, as in the prior art, the lens, that is, the objective lens is vertically moved vertically with respect to the recording surface of the optical disc, and focus control is performed so that the light beam constantly focuses on the recording surface of the optical disc during operation. It has a focus control mechanism. Further, in this embodiment, a means for manually adjusting the focus is provided in the lens holder support mechanism for supporting the lens holder of the focus control mechanism. That is, the support member mounting body 20-1 on which the support member 3 formed of a spring plate or a spring wire for suspending the lens holder (see FIG. 5) is mounted on the base 10 in the focus adjustment direction (optical axis direction). That is, the guide means 3 for guiding in the vertical direction of the drawing
0, and a moving holding means 40 for adjusting and holding the support member mounting body 20-1 in the vertical direction.

The support member mounting body 20-1 has the base end of the support member 3 attached thereto in the same manner as in the prior art, and is fitted into the concave groove 30-1a (guide means 30) of the column 50 erected on the base 10. A convex portion 30-1b having a trapezoidal cross section that fits and slides, and a screw hole 4 into which an adjusting screw 40-1 (movement holding means 40) is inserted.
0-1a.

The base 10 has a column 50 provided with the concave groove 30-1a vertically erected and an adjusting screw 40-1.
Is provided with a through-hole 10a on the axis of. Adjusting screw 40-1
Is screwed into the screw hole 40-1a of the support member mounting body 20-1 from above, and a screw-free tip (not shown) is rotatably penetrated through the through hole 10a of the base 10 to provide a spring property (not shown). Use a retaining ring to keep the play from falling out.

For manual focus adjustment, the adjustment screw 4
By manually rotating the 0-1 in the forward and reverse directions, the guiding means 3
The convex member 30-1b, which is 0, slides in the concave groove 30-1a to move the support member mounting body 20-1 in the vertical direction, and the support member 3 attached to the support member mounting body 20-1 is supported. The objective lens fixed to the lens holder to be moved can be moved and adjusted to a position near the reference position where the light beam is focused (to be as close as possible to the reference position) without bending the support member 3 and held at that position. . Although not shown, this movement adjustment is performed by passing a light beam through the objective lens, moving the objective lens up and down, and setting (locking) when the light spot formed on the recording surface of the optical medium has a circular minimum diameter.

Thereafter, as described with reference to FIG. 5 of the related art, the focus control can be performed in the same manner as in the related art by passing a forward or reverse current to the coils 5a and 5b fixed to the side surface of the lens holder 2. .

FIG. 2 shows a second embodiment. In the second embodiment, the movement of the support member mounting body 20-2 up and down by the movement holding means 40 (adjustment screw 40-1) is the same as that of the first embodiment, Body 20-2
Are different from each other in the guide means 30 for guiding the vertical direction.

That is, the base 10 has the guide rod 30-2a as the guide means 30 vertically erected, and the guide rod 30-2a
Fits into the shaft hole 30-2b of the support member mounting body 20-2,
The support member mounting body 20-2 is guided vertically.

For manual focus adjustment, the adjustment screw 4
By rotating 0-1 forward and backward, the support member mounting body 2
The objective lens 0-2 can be moved in the vertical direction along the guide rod 30-2a, and the objective lens can be moved and adjusted to the vicinity of the reference position without bending the support member 3, and can be held at that position. Subsequent focus control can be performed in the same manner as in the related art.

FIG. 3 shows a third embodiment. In the third embodiment, the guide means 3 erected vertically on the base 10 is provided.
0 (guide rod 30-2a) is a support member mounting body 20-3.
Is the same as that of the second embodiment in that the shaft hole 30-2b is inserted and the support member mounting body 20-3 is guided vertically along the guide rod 30-2a. -3 is provided with a lever 40-2 which is a movement holding means 40 for moving the -3 in the vertical direction.

The base 10 includes a guide rod 30-2a,
The column 50-1 is vertically erected at a position away from the guide rod 30-2a, and a support shaft (fulcrum) 50-1a protruding laterally at the end of the column 50-1 is provided with a lever 40-2. Is pivotally connected.

The lever 40-2 is engaged with a pin screw 40-2b having a long hole 40-2a formed at the tip thereof screwed into the side surface of the support member mounting body 20-3.
By further tightening 2b, lever 40-
Tighten 2 so that it cannot rotate. In addition, this pin screw 40-2b has a shaft portion having a head, and a tip portion is a male screw portion, and the length of the shaft portion is slightly smaller than the plate thickness of the lever 40-2. Tighten the lever 40-2 by screwing.

For manual focus adjustment, one end of the lever 40-2 is manually rotated about a support shaft (fulcrum) 50-1a to move the support member mounting body 20-3 to the guide rod 30-2.
The objective lens can be moved near the reference position without moving the support member 3 by bending the support member 3 by tightening the pin screw 40-2b along the vertical direction along the line a, and can be held at that position. Subsequent focus control can be performed in the same manner as in the related art.

FIG. 4 shows a fourth embodiment. In the fourth embodiment, the guide means 30 which stands vertically on the table 10 is provided.
(Guide rod 30-2a) is the same as that of the previous embodiment in that the shaft hole 30-2b of the support member mounting body 20-4 is fitted to guide the support member mounting body 20-4 in the vertical direction. And a dial-shaped gear 40-3a, which is a moving holding means 40 for moving the support member mounting body 20-4 in the vertical direction, and the gear 40
-3a is provided with a rack 40-3b that meshes with the rack 40-3b.

The support member mounting body 20-4 has a rack 40-3b which is engaged with the gear 40-3a on the side opposite to the side on which the support member 3 is mounted. The gear 40-3a is mounted on the base 1
The rack 50-3b is rotatably pivotally mounted on the column 50-2, which is vertically set up at 0, so as to mesh with the rack 40-3b, and the lock is performed by tightening the lock screws 50-2a provided on both sides of the column 50-2. Is done.

For manual focus adjustment, the gear 40-
By manually rotating the support member 3a, the support member mounting body 20-4 is moved up and down along the guide rod body 30-2a, and the objective lens is moved and adjusted near the reference position without bending the support member 3. , Can be held in that position. Subsequent focus control can be performed in the same manner as in the related art.

As described above, when assembling the focus control mechanism and the lens holder support mechanism in any of the above-described embodiments, the guide means of the focus adjustment mechanism of the present invention must be configured such that the guide member of the focus adjustment mechanism is a support member mounting body, that is, the objective lens is connected to the optical axis. In the direction (focus adjustment direction), the moving and holding means moves the objective lens (support member mounting body) along the guide means, and displaces the support member near the reference position where the light beam focuses on the optical recording medium surface. It can be moved and adjusted without being bent, and can be held at that position.

Therefore, the moving width of the objective lens by the subsequent focus control can be reduced, and the inclination of the objective lens with respect to the optical recording medium surface can be minimized by reducing the spring displacement of the support member. In addition, this movement holding means can be manually adjusted by the movement holding means as needed at any time during subsequent maintenance or the like, and the optical recording (or reproduction) characteristics of the optical head can be maintained. .

Although the lenses of the above embodiments have been described with respect to an objective lens which requires focus adjustment, the present invention can also be applied to manually moving and adjusting other lenses forming an optical path to a predetermined position. Needless to say.

[0033]

As described in detail above, according to the present invention,
Since the guide means and the movement holding means can hold the lens, for example, the objective lens in advance at the reference position where the light beam focuses on the optical recording medium surface, the movement width of the objective lens can be reduced in the subsequent focus control, and the objective lens can be reduced. Can be minimized with respect to the optical recording medium surface. Therefore, the optical recording (or reproduction) characteristics are not impaired, and an industrially useful effect such as improvement in manufacturing yield can be exhibited.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a first embodiment according to the present invention.

FIG. 2 is a schematic perspective view of a second embodiment according to the present invention.

FIG. 3 is a schematic perspective view of a third embodiment according to the present invention.

FIG. 4 is a schematic perspective view of a fourth embodiment according to the present invention.

FIG. 5 is a schematic side view of a conventional lens position adjusting structure.

[Explanation of symbols]

 1: lens (objective lens) 2: lens holder 3: support member 30: guide means 40: moving and holding means

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kyoko Miyabe 4-1-1, Kamidadanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Shingo Hamaguchi 4-1-1 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa No. 1 Inside Fujitsu Limited (72) Inventor Kazufumi Uno 4-1-1 Kamikodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fujitsu Limited

Claims (1)

[Claims] 1. A focus control mechanism for automatically adjusting a position of a lens for converging a light beam for recording or reproducing information on or from an optical recording medium, and a lens holder to which the lens is fixed is supported by a supporting member having a spring property. A lens holder support mechanism, the lens holder support mechanism comprising: guide means for guiding the support member along the optical axis direction; and movement holding means for moving the support member and holding the support member at a predetermined position. And a lens position adjusting structure for adjusting the position of the lens.