JPH11306549A - Optical pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mount an optical element on a frame with high positioning accuracy even when the frame is miniaturized and made thin. SOLUTION: Among optical systems 3 provided in an optical pickup device 1, first and second laser diodes 31 and 37, a full-reflection mirror 35 and a light receiving element 40 are fixed to an aluminum diecast frame 2, and an objective lens 36 is mounted on the frame 2 by interpolating an objective lens driving device 6. Remaining optical elements, i.e., a prism 33, a collimator lens 34, a half mirror 38 and a cylindrical lens 39, are attached to a resin-formed optical element fixing block 5 separate from the frame 2. In the optical element fixing block 5, a positioning surface is formed for each optical element. For mounting the optical element fixing block 5 on the frame 2, the position of the optical element fixing block 5 is adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup device used for recording and reproducing an optical recording disk such as a CD (compact disk) and a DVD (digital video disk / digital versatile disk). More specifically, the present invention relates to a structure for attaching an optical element to a frame of an optical pickup device.

[0002]

2. Description of the Related Art Various optical elements such as a laser light emitting element and a light receiving element are provided on a frame of an optical pickup device used for recording and reproducing an optical recording disk such as a CD and a DVD.
An objective lens driving device for driving an objective lens for condensing laser light emitted from a laser light emitting element on an optical recording disk in a focusing direction and a tracking direction is mounted.

[0003] In the frame, housings for all the optical elements are respectively formed, and each of these housings is provided with:
An alignment surface for aligning the optical element housed therein by contacting the optical element is formed. Since such an alignment surface requires high accuracy, it is formed by cutting a storage portion formed on an aluminum die-casting frame.

[0004]

However, if the frame is made smaller and thinner as the device becomes smaller and thinner, the housing for the optical element also becomes smaller. However, there is a problem that the alignment surface cannot be finished with high accuracy.

In view of the above problems, an object of the present invention is to mount an optical element on a frame with high positioning accuracy even if the frame is reduced in size and thickness as the device becomes smaller and thinner. To provide an optical pickup device capable of performing such operations.

[0006]

In order to solve the above problems, the present invention provides a laser light emitting device and an objective lens for condensing laser light emitted from the laser light emitting device on an optical recording disk in a focusing direction. An objective lens driving device driven in a tracking direction, a light receiving element for receiving return light from the optical recording disk, and a laser light emitted from the laser light emitting element until the laser light reaches the objective lens, and the optical recording A plurality of optical elements arranged between the return light from the disc and the light receiving element to the light receiving element, the laser light emitting element, the objective lens driving device, the light receiving element, and the optical element are mounted. An optical pickup device having at least one of the plurality of optical elements.
One is characterized in that it is mounted on the frame while being mounted on an optical element fixing block separate from the frame.

In the present invention, the optical element fixing block is preferably a resin molded product.

Further, in the present invention, it is preferable that the optical element fixing block is formed with a positioning surface of the optical element.

In the present invention, the optical element is attached to an optical element fixing block formed separately from the frame. For this reason, if the optical element fixing block is formed of a material having high molding accuracy, such as resin, the alignment surface of the optical element can be formed with high accuracy without performing post-processing such as cutting. Therefore, even if the apparatus is reduced in size and thickness, the alignment surface of the optical element can be formed with high accuracy, so that the alignment of the optical element can be performed accurately. Further, since the optical element fixing block is separate from the frame, the frame can be formed of a highly rigid material such as aluminum. Therefore, the rigidity of the optical pickup device can be ensured.

In the present invention, a laser light emitting element, a light receiving element and the like are attached after the optical element fixing block is attached to the frame, and an optical element fixing element is attached after the laser light emitting element and the light receiving element are attached to the frame. Blocks may be attached. In the latter case, it is preferable that a fixing block mounting portion for adjusting the position of the optical element fixing block when mounting the optical element fixing block is formed on the frame. With this configuration, when the optical element fixing block is mounted on the frame after the laser light emitting element or the light receiving element is mounted on the frame, the mounting position or direction of the laser light emitting element or the light receiving element is slightly shifted. Also, the optical element fixing block can be mounted on the frame in accordance with this state. Therefore, the optical axis of each optical element attached to the optical element fixing block can be aligned with the optical axes of the laser light emitting element, light receiving element, and objective lens already fixed to the frame.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical pickup device according to the present invention will be described below with reference to the drawings.

(Overall Configuration) FIG. 1 is a plan view of an optical pickup device according to the present invention. As shown in FIG. 1, the optical pickup device 1 moves the frame 2, the optical system 3 mounted on the frame 2, and the objective lens 36 of the optical system 3 in the focusing direction (focusing error correction direction).
And an objective lens driving device 6 for driving in the tracking direction (tracking error correction direction).

The frame 2 is an aluminum die-cast product having a constant thickness and extending horizontally. Almost half of the frame 2 has an optical system mounting portion 22 on which the optical system 3 is mounted, and the other half has an objective lens. The driving device mounting section 21 has the driving device 6 mounted thereon.

(Objective lens driving device 6) The objective lens driving device 6 is a lens holder 61 holding the objective lens 36.
And a holder supporting member 6 supporting the lens holder 61.
Two. The lens holder 61 is formed in a cylindrical shape, and a mounting portion 611 for the objective lens 36 is formed on the upper surface of the lens holder 61. A cylindrical bearing portion 612 is formed at the center of the lens holder 61, and a support shaft 63 standing upright from a bottom wall 621 of the holder support member 62 is inserted into the inner peripheral surface of the bearing portion 612. The focusing drive coil 65 is provided on the outer peripheral surface of the bearing portion 612.
The pair of tracking drive coils 64 is attached to the outer peripheral surface of the lens holder 61.

The holder support member 62 has a rectangular bottom wall 62, and a support shaft 63 for supporting the lens holder 61 is fixed to the center of the bottom wall 62. A side wall 622 that covers the outer peripheral surface of the lens holder 61 stands upright on the outer peripheral edge of the bottom wall 62. Tracking drive coil 64 of side wall 622
The tracking drive magnet 6 is located at a position facing the
6 is attached. Therefore, the lens holder 61 can be rotated around the support shaft 63 to perform tracking error correction. Further, a pair of inner walls 623 that face each other with the bearing 612 interposed therebetween is cut and raised inside the bottom wall 62. The inner wall 623 stands upright inside two openings 613 formed in the lens holder 61.
A focusing drive magnet 67 is attached to the inner wall 623 so as to face the focusing drive coil 65. Therefore, the lens holder 61 is connected to the support shaft 6.
3 can be moved in the axial direction to perform focusing error correction.

On the other hand, the driving device mounting portion 21 formed in the frame 2 is a rectangular through hole penetrating the frame 2 in the thickness direction, and its inner peripheral surface is formed with the side wall 622 of the objective lens driving device 6. They face each other with a slight gap. The objective lens driving device 6 is fitted into the driving device mounting portion 21, and a flange portion 624 projecting outward in the horizontal direction from two of the side walls 622 of the holder support member 62 is screwed to the frame 2. It is fixed at.

(Configuration of Optical System 3) The optical system 3 includes first and second laser diodes 31, 37 (laser light emitting elements), a diffraction grating 32, a prism 33, a collimating lens 34, and a total reflection mirror. 35 and an objective lens 36. The optical system 3 further includes a half mirror 38,
A light receiving element 40 is provided. First, the laser light emitted from the first laser diode 31 is diffracted by the diffraction grating 32 and deflected by the prism 33. This laser light is converted into parallel light by a collimating lens 34, and is launched upward of the frame 2 by a total reflection mirror 35. Just above the total reflection mirror 35,
Since the objective lens 36 held by the objective lens driving device 6 is arranged, the laser light is focused on an optical recording disk (not shown) by the objective lens 36.

The laser light emitted from the second laser diode 37 is deflected by the half mirror 38 and passes through the prism 33. This laser light is collimated by a collimating lens 34 and is totally reflected by a total reflection mirror 35.
Is raised toward the upper side of the frame 2. Therefore, the laser light is focused on the optical recording disk by the objective lens 36.

Return light from the optical recording disk passes through an objective lens 36, a total reflection mirror 35, and a collimator lens 34, passes through a prism 33, and reaches a half mirror 38. This return light passes through the half mirror 38, passes through the cylindrical lens 39, and is focused on the light receiving element 40. In the light receiving element 40, a reproduction signal included in the return light,
A focusing error signal and a tracking error signal of the objective lens 36 are detected.

(Mounting Structure of Optical Element) In the optical system 3 configured as described above, the objective lens 36 is mounted on the frame 2 while being mounted on the objective lens driving device 6 as described above. The drive device mounting portion 21 is provided in a portion of the frame 2 directly below the objective lens 36.
A pedestal 2 that protrudes inward and has an inclination of approximately 45 °
The base 26 has a total reflection mirror 3
5 is attached. Further, the first laser diode 31, the second laser diode 37, and the light receiving element 40 are inserted into mounting holes 23, 24, 25 formed on the side surface of the optical element mounting portion 22 of the frame 2. . The diffraction grating 3 is inserted through the holder 321 into the mounting hole 23 into which the first laser diode 31 is inserted.
Two are also stored. Through the mounting holes 23, 24, 25, through holes 231, 241, 2 serving as an optical path of the laser beam.
51 extend inward, the through holes 231 and
Reference numerals 41 and 251 open on the inner peripheral side surface 271 of the mounting portion 27 (fixing block mounting portion) of the optical element fixing block 5 described later.

The prism 33, the collimator lens 34, and the half mirror 3 which are the remaining optical elements of the optical system 3
8. The cylindrical lens 39 is attached to the optical element fixing block 5 separate from the frame 2 as described below.

(Configuration of Optical Element Fixing Block 5) FIG.
FIG. 4 is a perspective view showing a state in which an optical element is attached to the optical element fixing block 5. FIG. 3A shows an optical element fixing block 5 to which an optical element is attached, as shown in FIG.
FIG. 3B is a cross-sectional view taken along line I ′, and FIG. 3B is a cross-sectional view taken along line II-II ′ in FIG. 2 of the optical element fixing block to which the optical element is attached.

As shown in FIGS. 2, 3A and 3B, the optical element fixing block 5 is a resin molded product formed in a substantially rectangular parallelepiped. Front 5 of optical element fixing block 5
A mounting portion 51 of the collimator lens 34 is formed on the mounting surface 01, a mounting portion 52 of the prism 33 and a mounting portion 53 of the half mirror 38 are opened on the upper surface 503, and a mounting portion 54 of the cylindrical lens 39 is mounted on the rear surface 502. It is open.

The mounting portion 51 of the collimating lens 34 projects cylindrically from the front surface 501 of the optical element fixing block 5. The inner peripheral surface 511 of the mounting portion 51 is a first alignment surface of the collimator lens 34, and when the outer peripheral surface 341 of the collimator lens 34 abuts, a direction orthogonal to the optical axis of the collimator lens 34 (arrow Y, Z direction)
Is performed. A portion 512 of the front surface 501 of the optical element fixing block 5 which is surrounded by the mounting portion 51 is a second alignment surface of the collimator lens 34. When the end surface 342 of the collimator lens 34 contacts, the collimator lens Positioning in the optical axis direction (direction of arrow X) of 34 is performed. The front surface 512 of the optical element fixing block 5 and the mounting portion 52 of the prism 33 are mounted.
A through-hole 56 through which the laser light passes is formed between them.

The mounting portion 52 of the prism 33 is a concave portion having a substantially rectangular opening on the upper surface 503 of the optical element fixing block 5. Between the mounting portion 52 and the mounting portion 53 of the half mirror 38, an inner wall 55 projecting from both left and right sides of the inner peripheral side surface of the mounting portion 52 is formed. The bottom surface 52 of the mounting portion 52 of the prism 33 thus formed
Reference numeral 1 denotes a first alignment surface of the prism 33. When the lower surface 331 of the prism 33 abuts, the prism 3
3 is aligned in the up-down direction (the direction of arrow Y). Also, one inner peripheral side surface 52 of the mounting portion 52
Reference numeral 2 denotes a second alignment surface of the prism 52. When the side surface 332 of the prism 52 abuts, the prism 5
2 is performed in the left-right direction (direction of arrow Z). Further, the front surface 523 of the inner wall 55 is a third alignment surface of the prism 52, and
When the abutment 33 comes into contact, the positioning of the prism 52 in the front-back direction (direction of arrow X) is performed. The first laser diode 3 formed on the frame 2 is provided between the side surface 505 of the optical element mounting block 5 and the mounting portion 52 of the prism 33.
A through-hole 57 through which laser light passes is formed corresponding to the through-hole 231 of the one mounting hole 23.

The mounting portion 53 of the half mirror 38 is a concave portion having a pentagonal opening on the upper surface 503 of the optical element mounting block 5. On the inner surface of the mounting portion 53, a first inclined surface 532 extending perpendicularly to the optical axis of the collimating lens 34 and the cylindrical lens 39 with an inclination of approximately 45 °, and orthogonal to the first inclined surface 532. A second slope 533 is formed. Of the bottom surface of the mounting portion 53, a rectangular bottom surface 531 having two sides of the first slope 532 and the second slope 533 is a first alignment surface of the half mirror 38, and the lower surface of the half mirror 38 3
When 81 abuts, the vertical direction of the half mirror 38 (arrow Y
Direction) is performed. Also, the first slope 5
Reference numeral 32 denotes a second alignment surface of the half mirror 38, and the surface 3 of the half mirror 38 through which the laser light passes.
When the contact is made, the alignment of the half mirror 38 in the front-rear direction (the direction of arrow X) and the inclination angle of the half mirror 38 with respect to the laser beam are set. Further, the second inclined surface 533 serves as a third alignment surface of the half mirror 38. When the side surface 382 of the half mirror 38 abuts, the alignment of the half mirror 38 in the left-right direction (direction of arrow Z) is performed. Will be In addition, between the side surface 506 of the optical element mounting block 5 and the mounting portion 38 of the half mirror 38,
A through hole 58 through which laser light passes is formed corresponding to the through hole 241 of the mounting hole 24 of the second laser diode 37 formed in the frame 2.

Mounting section 54 for cylindrical lens 39
Is a concave portion opened in a circular shape on the rear surface 502 of the optical element fixing block 5. The inner peripheral surface 541 of the mounting portion 54 is a first alignment surface of the cylindrical lens 39. When the outer peripheral surface 391 of the cylindrical lens 39 abuts, a direction perpendicular to the optical axis of the cylindrical lens 39 (arrow Y, (In the direction of Z). The bottom surface 542 of the mounting portion 54 in the axial direction is a second alignment surface of the cylindrical lens 39. When the end surface 392 of the cylindrical lens 39 abuts, the optical axis direction of the cylindrical lens 39 (the direction of arrow X). Is performed. Between the bottom surface 542 of the mounting portion 54 and the mounting portion 53 of the half mirror 38, a through hole 59 through which laser light passes is formed.

(Mounting Structure of Optical Element Fixing Block 5) In the optical element fixing block 5 formed as described above, the prism 33, the collimating lens 34, the half mirror 38, and the cylindrical lens 39 are aligned as described above. It is aligned using the surface and is fixed by bonding. The optical element fixing block 5 includes the frame 2
Is attached to the mounting portion 27 of the optical element fixing block 5 formed in the above.

As shown in FIG. 1, the mounting portion 27 of the optical element fixing block 5 has a substantially rectangular opening inside the optical element mounting portion 22 formed in the frame 2 and penetrates in the thickness direction of the frame 2. It has a through hole. The inner peripheral surface 271 of the mounting portion 27 is
The front surface 501, rear surface 502, side surfaces 505 and 506, and the mounting portion 51 of the collimating lens 34 protruding from the front surface 501 are slightly opposed to each other. Therefore, when mounting the optical element fixing block 5, the mounting portion 27 can finely adjust the mounting position and the orientation of the optical element fixing block 5 with respect to the frame 2 by the gap.

After the optical element fixing block 5 is fitted into the mounting portion 27 and its mounting position and orientation are finely adjusted, the side surfaces 505 and 506 of the optical element fixing block 5 and the inner peripheral surface 271 of the mounting portion 27 are connected. The space is fixed with an adhesive 11. Thereafter, the first and second laser diodes 3
1, 37, the diffraction grating 32, the total reflection mirror 35, and the light receiving element 40 are fixed to the frame 2 while adjusting the optical axis.

(Effect of this Embodiment) As described above, in the optical pickup device 1 of this embodiment, the prism 3 of the optical element is used.
3, a collimator lens 34, a half mirror 38, and a cylindrical lens 39 are attached to an optical element fixing block 5 formed separately from the frame 2. Since the optical element fixing block 5 is formed of a resin having high molding accuracy, the alignment surface of the optical element can be formed accurately without performing post-processing such as cutting. Therefore, even if the optical pickup device 1 is made smaller and thinner so that the mounting portion of the optical element cannot be formed by post-processing of the frame 2, if the optical element fixing block 5 made of resin is used, the position of the optical element can be reduced. The mating surface can be formed with high accuracy. Therefore, with respect to the optical element fixing block 5,
Prism 33, collimating lens 34, half mirror 3
8, and the positioning of the cylindrical lens 39 can be performed accurately. Further, the optical element fixing block 5 can be accurately mounted on the frame 2. Further, since the optical element fixing block 5 is separate from the frame 2, the frame 2 can be formed of highly rigid aluminum. Therefore, compared with the case where the entire frame 2 is molded with resin or the like, the optical pickup device 1
High rigidity can be maintained.

(Other Embodiments) In the above embodiment, the optical element fixing block 5 is a resin molded product. However, the optical element fixing block is not limited to resin and may be formed of zinc or the like.

The optical elements mounted on the optical element fixing block 5 are not limited to those described above. For example, a total reflection mirror 35 may be mounted.

Further, in the above embodiment, after the optical element fixing block 5 is attached to the mounting portion 27 of the frame 2,
The first and second laser diodes 31 and 37, the light receiving element 40, and the like are attached to the frame 2;
Before attaching the optical element fixing block 5 to the first and second laser diodes 31, 37 and the diffraction grating 3
2, the total reflection mirror 35, and the light receiving element 40
And the objective lens driving device 6 holding the objective lens 36 can be attached to the frame 2.

In this case, the optical element fixing block 5
Of the first and second laser diodes 3
1 and 37, the optical axes 36L of the objective lens 36, and the optical axis 40L of the light receiving element 25 coincide with each other, and the laser beam is applied to the center of the objective lens 36. The position of the optical element fixing block 5 can be adjusted. Therefore, the laser diodes 31, 3
Even if the mounting positions and orientations of the light receiving element 7, the light receiving element 40 and the total reflection mirror 35 are slightly shifted, the optical element fixing block 5 can be mounted on the frame 2 in accordance with this state. Accordingly, the optical axis 5L of each optical element attached to the optical element fixing block 5 is connected to the first and second laser diodes 31 and 37 already fixed to the frame 2.
The light receiving element 40, the optical axis 31L of the objective lens 36, 3
It can be adjusted to 7L and 40L.

Further, in the above embodiment, the mounting portion 27 of the optical element fixing block 5 formed on the frame 2 is formed so that the position of the optical element fixing block 5 can be adjusted. Element fixing block 5
May be formed so that the position adjustment of the optical element fixing block 5 is not required.

The optical element fixing block 5 may be fixed to the frame 2 by screws or the like.

[0038]

As described above, in the optical pickup device of the present invention, at least one of the plurality of optical elements is attached to the optical element fixing block formed separately from the frame. Therefore, the optical element fixing block can be molded with a material having high molding accuracy such as resin, and the mounting surface of the optical element can be accurately molded without performing post-processing such as cutting. Therefore, even if the device is reduced in size and thickness, the alignment of the optical element can be performed accurately. Further, since the optical element fixing block is separate from the frame, the frame can be formed of a material having high rigidity such as aluminum to secure the rigidity of the optical pickup device.

[Brief description of the drawings]

FIG. 1 is a plan view showing an optical pickup device of the present invention.

FIG. 2 is a perspective view showing how an optical element is attached to an optical element fixing block of the apparatus shown in FIG.

FIG. 3A is a cross-sectional view of the optical element fixing block to which the optical element is attached, taken along a line II ′ in FIG. 2;
FIG. 2B is a cross-sectional view of the optical element fixing block to which the optical element is attached, taken along a line II-II ′ in FIG.

[Explanation of symbols]

 Reference Signs List 1 optical pickup device 2 frame 3 optical system 5 optical element fixing block 6 objective lens driving device 11 adhesive 27 mounting portion of optical element fixing block 31, 37 laser diode (laser light emitting element) 32 diffraction grating 33 prism 34 collimating lens 35 Total reflection mirror 36 Objective lens 38 Half mirror 39 Cylindrical lens 40 Light receiving element 51 Mounting section for collimating lens 52 Mounting section for prism 53 Mounting section for half mirror 54 Mounting section for cylindrical lens

Claims (4)

[Claims] A laser light emitting element; an objective lens driving device for driving an objective lens for condensing laser light emitted from the laser light emitting element on an optical recording disk in a focusing direction and a tracking direction; A light receiving element that receives the return light of the laser light, and a laser light emitted from the laser light emitting element reaches the objective lens, and a return light from the optical recording disk reaches the light receiving element from the objective lens. An optical pickup device having a plurality of optical elements disposed between the laser light emitting element, the objective lens driving device, the light receiving element, and a frame on which the optical element is mounted; At least one of them is mounted on an optical element fixing block separate from the frame. The optical pickup apparatus characterized by being mounted on the serial frame. 2. The optical pickup device according to claim 1, wherein the optical element fixing block is a resin molded product. 3. The optical pickup device according to claim 1, wherein an alignment surface of the optical element is formed on the optical element fixing block. 4. The method according to claim 1, wherein
An optical pickup device, wherein the frame is provided with a fixing block mounting portion capable of adjusting the position of the optical element fixing block when mounting the optical element fixing block.