JPH05325230A - Skew adjusting mechanism for objective lens - Google Patents

Abstract

PURPOSE:To facilitate adjustment, to prevent disorder after adjustment, to simplify the structure, to eliminate the need for pursuing the dimension precision or the like of each parts and to reduce the cost in a skew adjusting mechanism for objective lens in which a lens block holding an objective lens is supported on an optical block provided with other optical parts so that the angle can be adjusted. CONSTITUTION:Three slopes 11, 11, and 11 are formed to surround an aperture 9 formed in the block base 6 of a lens block 3 correspondingly to an objective lens 2, and semispherical projecting parts 14, 14, and 14 surrounding the peripheral edge of an aperture 13 and corresponding to these slopes are formed on the upper face of a block housing 12 of an optical block 4. The lens block is so sat that slopes are brought into contact with projecting parts of the optical block, and the lens block is inclined to the optical block.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel objective lens skew adjusting mechanism. More specifically, it relates to a skew adjustment mechanism for an objective lens that supports a lens block that holds the objective lens with respect to an optical block that includes other optical components so that the skew can be adjusted. In addition, it is an object of the present invention to provide a novel skew adjustment mechanism for an objective lens, which has a simple structure, does not need to pursue the dimensional accuracy of each component, and can reduce the cost.

[0002]

2. Description of the Related Art In order to optimize the signal reading performance of an optical pickup device, the inclination of an objective lens is adjusted with respect to an optical block on which other optical components are mounted, that is, skew adjustment is performed.

In such skew adjustment, the objective lens is supported on a lens block, the lens block is supported so that the angle can be adjusted with respect to an optical block on which other optical parts are mounted, and the mounting angle of the lens block with respect to the optical block is adjusted. It is designed to be changed.

7 and 8 show a conventional skew adjusting mechanism for an objective lens.

In the figure, reference numeral a denotes an optical pickup device, which comprises a lens block c having an objective lens b and an optical block d having predetermined optical parts.

The lens block c comprises a plate-shaped block base e which is elongated in one direction and a biaxial actuator f supported by the block base e.

Although the details of the biaxial actuator f are omitted, the objective lens b is configured to be movable in the vertical direction (focusing direction) and the horizontal direction (tracking direction) by a driving mechanism.

The block base e has an opening g formed at a position corresponding to the objective lens b of the biaxial actuator f. The peripheral edge of the opening g projects to the lower surface side and the lower surface h has a convex spherical surface. It is formed on the mounting surface that forms a part.

The biaxial actuator f is fixed to the block base e by screws.

Reference numerals i and i denote screw holes formed in the peripheral portion of the opening g of the block base e at appropriate intervals in the circumferential direction,
Reference numeral j is a pin insertion hole formed at a position appropriately spaced from the screw holes i, i in the circumferential direction of the opening g.

Although details of the optical block d are omitted, optical components such as a laser diode, a grating, a photodiode, and a beam splitter are arranged in the block housing k, and a laser beam oscillated from the laser diode is formed on the upper surface. The light is emitted upward from the opened opening l.

M is a seating surface having a shape which forms a part of a concave spherical surface formed on the periphery of the upper opening l of the optical block d,
The seating surface m is formed to have substantially the same curvature as that of the mounting surface h of the block base e.

Reference numerals n and n denote outer peripheries of the seating surface m of the optical block d, which are screw insertion holes formed at positions respectively corresponding to the two screw holes i of the block base e.
Is a pin insertion hole formed on the outer periphery of the seating surface m at a position corresponding to the pin insertion hole j of the block base e.

To connect the lens block c and the optical block d, first, the mounting surface h of the block base e to which the biaxial actuator f is screwed is the seating surface m of the block housing k of the optical block d. Are overlapped with each other from above, and at the positions where these pin insertion holes j and o coincide with each other when viewed from above, the caulking pins p are inserted and crimped.

Next, screws q and q are inserted into the screw insertion holes n and n from below the block housing k, and the portions of the screws q and q protruding upward from the upper surface of the block housing k are attached to the block base e. The lens block c is coupled to the optical block d by screwing the screw holes i, i into the screw holes i.

In the state where the block base e is connected to the block housing k, the mounting surface h of the block base e is placed.
Is substantially in surface contact with the seating surface m of the block housing k.

Therefore, the angle adjustment of the lens block c with respect to the optical block d is performed by inserting screws from the lower surface of the block housing k into the screw insertion holes n, n and screwed into the screw holes i, i of the block base e. It is carried out by appropriately screwing in or untwisting q and q.

That is, when one screw q is screwed in, the center of the block base e is a line connecting the portion where the other screw q is screwed and the portion where the caulking pin p is inserted. When the screw hole i part is inclined so as to approach the block housing k, and when one of the screws q is unscrewed back, the block base e conversely has the one screw hole i part of the block housing k. Inclined to move away.

Further, the block base e is inclined with respect to the block housing k with the line connecting the crimping pin p and the one screw q as the center line by screwing in or unscrewing the other screw q. become.

When the block base e is tilted with respect to the block housing k, the mounting surface h of the block base e is pressed against the seating surface m of the block housing k,
Or, they will slide while being separated from each other.

When the angle adjustment of the block base e with respect to the block housing k is completed, the screws q and q are prevented from rotating, and therefore the adhesive is applied to the screwed portions of the screw holes i and i and the screws q and q. Is applied, and the skew adjustment of the objective lens b is completed.

[0022]

However, in the above-described conventional skew adjusting mechanism for the objective lens, the lens block c and the optical block d are coupled to each other by the mounting surface h of the block base e and the optical block. Since it is performed in a substantially surface contact with the seating surface m of d, there is a large resistance to the movement of the lens block c with respect to the optical block d during the angle adjustment, and the surface accuracy of both surfaces h and m must be high. The movement is not smooth, and because the movement is not smooth, there is a problem that the responsiveness of the movement of the lens block to the rotation of the adjustment screw is lacking, and therefore the adjustment accuracy cannot be improved.

Further, the movement of the lens block c with respect to the optical block d by screwing in or unscrewing the screws q, q does not slide around the center of the sphere formed by the both sides h and m, so that it is placed on the mounting surface. The surface h and the seating surface m are almost never in contact with each other with a uniform pressure at each contacting portion, so that the contact state between them is unstable, and after adjustment, internal stress is applied to the contacting portions of both blocks. There is a problem that the movement of the block may stop when it is still generated, and when the block is fixed with an adhesive in such a state, the two are easily displaced due to vibration or the like.

[0024]

Therefore, in order to solve the above-mentioned problems, the skew adjusting mechanism of the objective lens of the present invention has at least one block in the joint portion between the lens block and the optical block, which is appropriately separated from each other. Forming a spherical projection having a spherical surface which is a part of three spherical surfaces,
On the other block, a flat surface or a curved surface inclined at a predetermined angle is formed at a position corresponding to the spherical projection, and the lens block is seated on the optical block so that the spherical projection contacts the flat surface. The block is tilted with respect to the optical block.

[0025]

Therefore, according to the skew adjusting mechanism of the objective lens of the present invention, the joint portion between the lens block and the optical block is supported at at least three points, and the joint portion between both blocks is only point contact. There is little resistance to the movement of the block, and smooth movement can be realized accordingly, and the responsiveness of the movement of the lens block to the rotation of the adjustment screw is improved, which can improve the adjustment accuracy and both. The angle can be easily adjusted.

Further, since the contact between both blocks is point contact, the movement of the blocks does not stop when internal stress is generated in the contact portions of both blocks when the angles of both blocks are adjusted. After adjustment, the positional relationship between the two blocks will not be displaced due to vibration or the like.

Further, since the contact between both blocks is the spherical projection and the flat surface or the curved surface, it is not necessary to increase the surface accuracy or the dimensional accuracy of each part, and the structure is simple and the cost can be reduced accordingly. ..

[0028]

The details of the skew adjusting mechanism for an objective lens of the present invention will be described below with reference to the respective embodiments shown in the accompanying drawings.

1 to 4 show a first embodiment in which a skew adjusting mechanism for an objective lens according to the present invention is applied to an optical pickup device.

In FIG. 1, reference numeral 1 denotes an optical pickup device, which comprises a lens block 3 having an objective lens 2 and an optical block 4 having other optical components, and an optical disk 5 is positioned so as to face the objective lens 2. To be done.

The lens block 3 is a flat block base 6, a biaxial actuator 8 supported by the block base 6, and a cover body 7 attached to the block base 6 so as to cover the biaxial actuator 8. Consists of.

Although the details of the biaxial actuator 8 are omitted, the biaxial actuator 8 is provided so that the objective lens 2 can be moved vertically (focusing direction) and horizontally (tracking direction) by a driving mechanism.

The biaxial actuator 8 is arranged on the upper surface of the block base 6, and an opening 9 is formed at a position corresponding to the objective lens 2.

Reference numerals 10, 10 and 10 denote receiving pieces formed in a cut-and-raised shape at three locations substantially concentric with the opening 9 of the block base 6, and the lower surface of the receiving piece 10 has an inclined surface 11 having a predetermined angle. Has become.

The inclined surfaces 11, 11, 11 are formed so that the orthogonal lines passing through the substantially central portion thereof intersect at the focal point on the upper side of the objective lens 2.

Although the details of the optical block 4 are omitted, a laser diode is provided in the block housing 12,
Optical components such as a grating, a photodiode, and a beam splitter are provided so that a laser beam oscillated from the laser diode is emitted upward through an opening 13 formed in the upper surface.

14, 14, 14 are block housings 1.
2 are hemispherical projections formed on the upper surface of 2 at three locations concentric with the opening 13 thereof, and these projections 14, 14, 14 correspond to the slopes 11, 11, 11 of the block base 6 respectively. And the block base 6 is the block housing 1
When each of the slopes 11, 11, 11 is placed on the projection 2,
4, 14, 14 are in contact with each other.

In this state, the opening 13 of the block housing 12 and the opening 9 of the block base 6 are substantially aligned when viewed from above.

Reference numeral 15 denotes a spring placement hole formed at one corner of the block base 6, and a spring hooking portion (not shown) is formed near the opening peripheral edge on the upper surface side.

Reference numeral 16 denotes a spring disposing recess formed at a position corresponding to the spring disposing hole 15 of the block housing 12, and a spring hooking portion (not shown) is formed at the bottom of the spring disposing recess 16.

Reference numeral 17 is a lens block 3 and an optical block 4.
Is a tension spring for elastically coupling and, the tension spring 17 is inserted through the spring arrangement hole 15 of the block base 6 and is located in the spring arrangement recess 16 of the block housing 12, and its upper end is The tension spring 17 is stretched between the block base 6 and the block housing 12 by being locked to the spring hook portion of the spring placement hole 15 and the lower end thereof to the spring hook portion of the spring placement recess 16, respectively. ..

Numerals 18 and 18 are screw holes formed in the block base 6, and each of the two side edges separated from the corner of the block base 6 in which the spring arranging hole 15 is formed is separated from a substantially central portion thereof. It is formed at the inner position.

Numerals 19 and 19 are screw insertion holes formed at positions corresponding to the screw holes 18 of the block base 6 of the block housing 12 so as to vertically penetrate therethrough. A downward step surface 19a is formed at an intermediate portion in the lengthwise direction, a head of a screw described later is engaged with the step surface 19a, and a screw shaft of the screw is provided above the step surface 19a. The part is designed to be inserted.

Reference numerals 20 and 20 denote screws for connecting the lens block 3 and the optical block 4, respectively.
0 is inserted into the screw insertion holes 19 and 19 of the block housing 12 from below, and the portions protruding from the upper surface thereof are individually screwed into the screw holes 18 and 18 of the block base 6.

Then, the lens block 3 has its slope 1
1, 11, and 11 are the projections 14, 14, and 1 of the optical block 4.
4 is connected to this in a substantially point contact manner.

The lens block 3 and the optical block 4, which are connected to each other by one tension spring 17 and two screws 20 and 20, are subjected to relative angle adjustment in the following manner.

That is, the optical block 4 of the lens block 3
The angle adjustment with respect to the screw hole 1 of the block housing 12 is made through the screw insertion holes 19 of the block housing 12.
This is done by appropriately screwing or unscrewing the screws 20 and 20 screwed into the screws 8 and 18.

For example, when one screw 20 is screwed in, the screw hole 18 of the block base 6 into which the one screw 20 is screwed.
The slopes 11, 11, 11 are provided with protrusions 14, 1 so that the corresponding portions of the block housing 12 are close to each other.
Sliding with respect to 4 and 14, the angle of the lens block 3 with respect to the optical block 4 is changed.

At this time, the lens block 3 has its slope 1
Since the perpendicular lines passing through the substantially central portions of 1, 11, 11 are formed so as to intersect with each other at the upper focus of the objective lens 2,
It is tilted around the intersection.

Further, since the distance between the lens block 3 and the optical block 4 is moved in the direction in which the distance between the lens block 3 and the optical block 4 is separated at the portion where the tension spring 17 is locked, the tension spring 17 is extended, and the lens block is extended. 3 is the slope 11,
11 and 11 are held in a state of being elastically contacted with the protrusions 14, 14 and 14 of the optical block 4.

Next, when one of the screws 20 is unscrewed back, the screw holes 18 of the block base 6 into which the one screw 20 is screwed and the corresponding portion of the block housing 12 are moved away from each other. 11, 11, 11 are protrusions 14, 14,
Sliding with respect to 14, the angle of the lens block 3 with respect to the optical block 4 is changed.

At this time, at the portion where the tension spring 17 is locked, the distance between the lens block 3 and the optical block 4 is moved in a direction in which they are close to each other due to the pulling force of the tension spring 17.

Further, the other screw 20 is screwed in or unscrewed in the same manner as the one screw 20, so that the angle adjustment in a direction different from the tilting direction by the one screw 20 is performed.

FIG. 5 and FIG. 6 show a second example in which the skew adjusting mechanism of the objective lens of the present invention is applied to the optical pickup device 1A.
FIG.

The optical pickup device 1A shown in the second embodiment differs from the optical pickup device 1 shown in the first embodiment in that the slope formed on the lens block side is a curved surface. Since there are only certain points, the description of the second embodiment will be made mainly on the differences from the first embodiment, and the other parts will be the same as the reference numerals given to the same parts in the first embodiment. The description is omitted by attaching the reference numerals.

Reference numerals 21, 21 and 21 denote receiving pieces formed in a cut-and-raised shape at three locations substantially concentric with the opening 9 of the block base 6, and the lower surface of the receiving piece 21 has a surface having a predetermined curvature. It is formed on the curved surface 22.

The curvature of the curved surface 22 is such that the normal line passes through the focal point on the upper side of the objective lens 2 and the focal point is at the center of the curved surface 22.

However, even in such an optical pickup device 1A, as in the optical pickup device 1 in the first embodiment, the block base 6 is supported by making point contact with the block housing 12 at three points. Further, since the normal lines of the curved surfaces 22, 22, 22 are formed so as to intersect with each other at the upper focus of the objective lens 2, the movement of the block base 6 with respect to the block housing 12 is always the objective lens. Since it tilts about the upper focal point of 2, the objective lens 2 and the optical disc 5 at the time of adjustment
The positional relationship between and does not go wrong.

[0059]

As is apparent from the above description, in the skew adjusting mechanism of the objective lens of the present invention, the lens block in which the objective lens is movably supported in the focusing direction and the tracking direction and the angle adjustment of the lens block are performed. An optical block that supports the optical block and is provided with other optical components, and a spherical surface, which is a part of at least three spherical surfaces appropriately separated from each other, is provided in one block at the joint between the lens block and the optical block. And a flat surface inclined at a predetermined angle is formed at a position corresponding to the spherical projection on the other block, and the spherical block is brought into contact with the flat surface to form an optical lens block. It is characterized in that the lens block is seated on the block and the lens block is tilted with respect to the optical block.

Therefore, according to the skew adjusting mechanism of the objective lens of the present invention, the joint between the lens block and the optical block is supported at at least three points, and the joints of both blocks are only point contact, so There is little resistance to the movement of the block, and smooth movement can be realized accordingly, and the responsiveness of the movement of the lens block to the rotation of the adjustment screw is improved, which can improve the adjustment accuracy and both. The angle can be easily adjusted.

Moreover, since the contact between both blocks is point contact, the movement of the blocks does not stop when internal stress is generated in the contact portions of both blocks when the angles of both blocks are adjusted. After adjustment, the positional relationship between the two blocks will not be displaced due to vibration or the like.

Furthermore, since the contact between the two blocks is the spherical projection and the flat surface or the curved surface, it is not necessary to increase the surface accuracy or dimensional accuracy of each part, and the structure is simple and the cost can be reduced accordingly. ..

In each of the above embodiments, an inclined surface or curved surface inclined at a predetermined angle is formed on the lens block side,
Although the one in which the spherical projection is formed on the optical block side has been described, the present invention is not limited to this, and a slope or a curved surface inclined at a predetermined angle may be formed on the optical block side and the spherical projection may be formed on the lens block side. good.

Further, the inclined surface or the curved surface inclined at a predetermined angle is formed so that the normal line or the normal line passing through the substantially central portion intersects at the focal point on the upper side of the objective lens. It may be done.

Furthermore, the concrete shapes and structures shown in the above-mentioned respective embodiments are merely examples of the embodiment in implementing the skew adjusting mechanism of the objective lens of the present invention, and the present invention is thereby realized. The technical scope should not be construed as limiting.

[Brief description of drawings]

FIG. 1 shows a first embodiment in which the skew adjusting mechanism for an objective lens of the present invention is applied to an optical pickup device together with FIGS. 2 to 4, and this drawing is a side view schematically showing the same.

FIG. 2 is a plan view.

FIG. 3 is a sectional view taken along the line III-III in FIG.

4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a sectional view showing a second embodiment of the skew adjusting mechanism of the objective lens of the present invention together with FIG.

FIG. 6 is an enlarged cross-sectional view showing a main part.

FIG. 7 shows a conventional skew adjusting mechanism for an objective lens together with FIG. 8, and this figure is an exploded perspective view.

FIG. 8 is an enlarged sectional view.

[Explanation of symbols]

 2 Objective Lens 3 Lens Block 4 Optical Block 11 Plane 14 Spherical Projection 22 Curved Surface

Claims (4)

[Claims] 1. A lens block having an objective lens, which is movably supported in a focusing direction and a tracking direction, and an optical block which supports the lens block such that its angle can be adjusted and which is provided with other optical parts. At the joint between the optical block and the optical block, one block is formed with a spherical projection having a spherical surface which is a part of at least three spherical surfaces appropriately separated from each other, and the other block is provided with a position corresponding to the spherical projection. A flat surface that is inclined at a predetermined angle is formed, the lens block is seated on the optical block so that the spherical projection contacts the flat surface, and the lens block is tilted with respect to the optical block. The objective lens skew adjustment mechanism. 2. A lens block comprising an objective lens, which is movably supported in a focusing direction and a tracking direction, and an optical block which supports the lens block such that its angle can be adjusted and includes other optical parts. At least three spherical projections that are appropriately separated from each other are formed in one of the joints between the optical block and the optical block, and the other block has a curved surface inclined at a predetermined angle at a position corresponding to the spherical projection. A skew adjusting mechanism for an objective lens, characterized in that the lens block is seated on the optical block so that the spherical projection contacts the curved surface, and the lens block is tilted with respect to the optical block. 3. The skew adjusting mechanism for an objective lens according to claim 1, wherein a plane inclined at a predetermined angle is formed so as to face the disk side focal point of the objective lens. 4. The skew adjusting mechanism for an objective lens according to claim 2, wherein a normal line of the curved surface inclined at a predetermined angle passes through a focus on the disk side of the objective lens.