JP2006260678A - Optical pickup device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical pickup device having a mechanism in which positional precision in the rotative position adjustment of a grating is stable with a small number of parts. <P>SOLUTION: The optical pickup device is provided with a plate shaped section 22f that is integrally formed from the peripheral section of a cylindrical holder 22, to which a grating 3 is fixed, and has elastic force so that elastic deformation can be made along the optical axis of laser light beams and an abutting section which can abut to the device frame formed on the plate shaped section. On the other hand, the device frame side storage section, which stores the cylindrical holder 22, is provided with a reference surface 21c which is orthogonal to the optical axis direction and controls the position of the grating 3 along the optical axis direction and a plane section 26a which is arranged opposite to the abutting section. The holder 22 or the grating 3 is abutted to the reference surface in a pressed manner by the fact that the abutting section is abutted to the plane section 26a and the plate shaped section is elastically deformed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to an optical pickup device for performing a reproducing operation or the like of a recording medium such as a CD or a DVD, and more particularly to an improvement of a mounting portion of a grating incorporated for generating a tracking error signal or the like.

  In general, an optical system of an optical pickup device used for reproducing information from or recording information on a recording medium such as a CD or a DVD is a laser diode as a laser light source and a grating that diffracts a laser beam emitted from the laser diode. And an objective lens that focuses the diffracted light on the optical recording medium, and a photodetector that receives the return light from the optical recording medium via the objective lens, so that the positions of the optical components can be adjusted. In addition, for example, the grating is attached to the device frame so as to be movable in the optical axis direction of the laser beam and rotatable around the optical axis, and after adjusting the position and the rotational position in the optical axis direction, It is fixed to the side of the apparatus frame by an adhesive or the like.

As such an optical pickup capable of adjusting the position of the grating, a holder to which the grating is fixed, an apparatus frame side accommodating portion in which the holder is movably accommodated, a laser diode, a laser diode, and the holder And a coil spring that presses and fixes the holder to the device frame side accommodating portion, and has a structure in which a spacer is sandwiched between the holder and the coil spring. According to this configuration, since the spacer is sandwiched between the holder holding the grating and the coil spring so that the holder and the coil spring are not in direct contact with each other, the phase adjustment is easy. (For example, see Patent Document 1)
JP 2000-285494 A

  However, the one described in Patent Document 1 has the following problems to be solved.

To adjust the mounting position of the grating, the positioning spacer, the holder to which the grating was mounted, the spacer, the coil spring, and the laser laser diode were inserted in this order from the opening of the housing on the apparatus frame side, and the position in the optical axis direction was adjusted. Thereafter, a jig is inserted from a through-hole opened in the accommodating portion, and the holder is rotated about the optical axis to adjust the rotational position. After the rotation adjustment, the elastic return force of the coil spring is adjusted. May act as a rotational force on the holder and may deviate from the position after the rotation adjustment. That is, it is difficult for the spacer between the coil spring and the holder to stand up the rotational force completely. Furthermore, the laser diode is constantly loaded by a reaction force that pushes the coil spring holder, and the laser diode may be displaced from a predetermined position. In addition, since spacers and coil springs are used, the number of parts increases, which is not desirable in terms of cost.

  In view of the above points, an object of the present invention is to provide an optical pick-up device including a mechanism that has a stable position accuracy and a small number of parts when adjusting the rotational position of a grating.

In order to solve the above problems, in the present invention, a grating that diffracts a laser beam emitted from a laser light source, a cylindrical holder in which the grating is fixed and both ends are opened, and the holder are rotatably accommodated. In the optical pickup device having an apparatus frame side accommodating portion and a pressing means for pressing and fixing the holder to the apparatus frame side accommodating portion, the pressing means is formed integrally with the holder. And

In the present invention, it is preferable that the pressing means has an elastic deformation portion that elastically deforms in the optical axis direction of the laser light. With this configuration, since the pressing means having an elastically deforming portion integral with the holder is used as compared with the conventional one using a coil spring, the rotational restoring force after the rotation adjustment is not generated, and the position is reduced. Adjustment accuracy is improved.

Furthermore, in the present invention, the pressing means includes a plate-like portion extending in the radial direction from the peripheral portion of the holder, and a contact portion formed on the plate-like portion and capable of contacting the device frame side accommodating portion. The apparatus frame side accommodating portion is provided with a reference plane that is orthogonal to the optical axis direction and restricts the position of the grating in the optical axis direction, and a flat portion that faces the reference plane. And
When the abutting portion abuts on the flat surface portion and the plate-like portion is elastically deformed, the holder or the grating abuts on the reference surface in a biased state, and the position of the grating in the optical axis direction is regulated. It is preferable. With such a configuration, the accuracy of adjusting the optical axis position and the rotational position of the grating is improved, and the plate-shaped portion that is elastically deformed extends in the radial direction, so that the optical axis direction can be shortened.

  Furthermore, in the present invention, it is preferable that the abutting portion is a protruding portion that protrudes from the plate-like portion in the plane portion direction. With such a configuration, the slidability between the holder and the flat portion of the apparatus frame side accommodating portion is improved and workability is improved as compared with the case where the surface of the plate-like portion is brought into contact.

  In the present invention, it is preferable that the tip of the protrusion is formed in an arcuate shape. With such a configuration, the contact is further made by line contact, and the slidability between the holder and the flat portion of the apparatus frame side accommodating portion is increased, and the workability is further improved.

  Further, the plate-like portion extends leftward and rightwardly symmetrically from the position at the peripheral portion located symmetrically with respect to the center of the holder, and the flat portion extends from the device frame to the tip surface thereof. Are formed of inner walls of a pair of left and right wall portions that are formed so as to protrude from each other with the first space portion therebetween, and the first space portion is larger than the diameter of the cylindrical outer shape portion of the holder and the plate Is set to a size smaller than the length between both side end portions of the shaped portion, and constitutes a part of the device frame side accommodating portion at a position facing the inner wall surface, and is substantially equal to the outer diameter of the cylindrical holder. A holding portion for holding the holder having the same inner diameter is provided, and a second space portion between the flat portion and an end surface of the holding portion facing the inner wall surface is connected to the first space portion. It is preferable to form. If comprised in this way, mounting | wearing to the apparatus frame side accommodating part of a holder will become easy. That is, when the holder is attached to the apparatus frame side accommodating portion, the plate-like portion is positioned in a direction perpendicular to the separating direction of the pair of wall portions and inserted from the first space portion, and the holder is rotated by 90 degrees. Then, the abutting portion of the plate-like portion abuts on the inner wall surface with an elastic force and can be mounted on the apparatus frame side accommodating portion. Further, since the plate-like portion extends symmetrically, the spring pressure does not change during the rotation adjustment of the holder, so that the rotation adjustment is easy.

  Furthermore, it is preferable that the size of the first space portion is larger than the outer shape of the case housing the light emitting element of the laser light source. If comprised in this way, the insertion space of the said case can be ensured, the freedom degree of the attachment position in the optical axis direction of a laser light source increases, and it becomes easy to adjust a position.

In the optical pickup device of the present invention, a grating that diffracts laser light emitted from a laser light source, a cylindrical holder in which the grating is fixed and both ends are open, and an apparatus frame in which the holder is rotatably accommodated In an optical pickup device having a side housing portion and a pressing means for pressing and fixing the holder to the device frame side housing portion,
The pressing means is integrally formed with the holder. Therefore, conventional coil springs and spacers are unnecessary, and the number of parts can be reduced. Further, no elastic restoring force (rotational force) is generated, and the accuracy of position adjustment is improved.

  An optical pickup device to which the present invention is applied will be described below with reference to the drawings.

(Schematic configuration of optical pickup device)
FIG. 1 is a schematic configuration diagram showing an optical system of an optical pickup device to which the present invention is applied.

  The optical system of the optical pickup device 1 includes a light source unit 4 including a laser diode 2 and a grating 3, and a beam splitter 5 for separating laser light emitted from the light source unit 4 from return light from the optical recording medium 10. A collimating lens 6 for converting the laser light from the light source unit 4 into parallel light, and an objective lens 7 for converging the parallel light from the collimating lens 6 onto the recording surface of an optical recording medium 10 such as a CD or DVD. In addition, a photodetector 9 for receiving the return light from the optical recording medium 10 through the sensor lens 8 is provided. The laser diode 2 has a light emitting element 2a and a case 2b for accommodating the light emitting element 2a.

  In the optical pickup device 1 having such an optical system, the laser light emitted from the light source unit is reflected by the beam splitter 5, then collimated by the collimator lens 6, and then condensed by the objective lens 7. Thus, the information recording surface of the optical recording medium 10 is focused. Further, the return light reflected by the optical recording medium 10 passes through the objective lens 7, the collimating lens 6, and the beam splitter 5, enters the light receiving surface of the signal detection photodetector 9, and enters the light receiving surface. Based on the amount of received light, an information reproduction process or the like is performed by a drive control device (not shown).

(Arrangement configuration of cylindrical holder, device frame, etc.)
2 to 5 are respectively a perspective view, a plan view, and a cylindrical holder, a spacer, and an apparatus frame constituting the optical pickup device, showing the arrangement of the light source unit and the cylindrical holder of the optical pickup device as viewed obliquely from above. The exploded perspective view which shows a part, and sectional drawing which shows the state which mounted | wore the apparatus frame with the cylindrical holder are shown.

  The light source unit 4 includes a cylindrical housing portion 21 formed on the device frame 20 of the optical pickup device 1, a cylindrical holder 22 having one end side inserted in a coaxial state from the one end opening 21 a, and the cylindrical holder 22 The grating 3 attached to the tip with an adhesive 24 and the slit 23 serving as a first space portion provided so as to face the one end opening 21a side of the apparatus frame 20 and opened in the optical axis direction. A laser diode 2 is provided. That is, the cylindrical accommodating portion 21 is a holding portion for holding the cylindrical holder 22, and the holder 22 is movable in the direction of the optical axis L of the laser beam and rotates about the optical axis L. Possible dimensions.

  Here, in the light source unit 4 of the present embodiment, the reference for regulating the position of the grating 3 in the optical axis L direction on the annular protrusion 21b formed at the front end opening of the cylindrical housing portion 21 at the front end side of the cylindrical holder 22. It abuts against an annular end surface 21c as a surface through a washer 25 as a positioning spacer. The annular end surface 21c serving as the reference surface is a surface orthogonal to the optical axis L direction. On the other hand, the rear end side of the cylindrical holder constitutes a slit portion 23 as a first space portion of the apparatus frame 20, and the one end opening 21a side of the wall portion 26 that is formed to project from both the right and left sides orthogonal to the optical axis L direction. The cylindrical holder 22 is held in contact with the flat surface portion 26a facing the surface.

  That is, the cylindrical holder 22 is held by the device frame 20 in a state where the annular end surface 21c of the device frame 20 and the flat portion 26a of the wall portion 26 are pressed and urged by an elastic force described later. On the other hand, the flat portion 26a faces the one end opening 21a side of the cylindrical housing portion 21 of the apparatus frame with a gap. In addition, the plane portion 26a is separated by a distance that is larger than the diameter of the cylindrical outer portion of the holder 22 and smaller than the length between both end portions of the plate-like portion 22f of the cylindrical holder 22 described later. 20, the inner wall surface of a pair of left and right wall portions formed so as to protrude toward the center of the one end opening 21 a. The edge 26b of the inner wall surface is formed in a slope shape.

Therefore, a groove-like accommodation portion 27 as a second space portion, which is formed between the flat portion 26a and the peripheral edge portion 21d of the opposite end opening 21a and accommodates the rear end side of the cylindrical holder, and the cylinder. A device frame side housing portion that houses the cylindrical holder is constituted by the shaped housing portion 21. The slit portion 23 (first space portion) and the groove-like storage portion 27 (second space portion) are in communication with each other, and the cylindrical holder 22 is inserted into the cylindrical shape via the space portions. It can be inserted into the storage portion 21 of this.

  The washer 25 is a molded product made of, for example, a synthetic resin material, and has an outer diameter that is substantially the same as the inner diameter of the housing portion 21, and a circular light passage hole 31 for passing laser light is formed at the center. Has been. Further, both surfaces of the washer 25 are smooth flat surfaces having a small friction coefficient so that the rotation adjustment of the grating described later can be smoothly performed.

  A circular through hole 21e is formed in the outer peripheral wall 20a of the cylindrical accommodating portion 21, and a groove extending in the direction of the optical axis L is formed at a portion of the outer peripheral surface of the cylindrical holder 22 facing the through hole 21e. 22e is formed.

  The laser diode 2 is held by holders 30 from both sides at the base end side of the laser diode, and the holders 30 can be attached to the apparatus frame 20.

(Specific configuration of cylindrical holder)
FIGS. 6A, 6B, and 6C are a perspective view of the cylindrical holder as viewed obliquely from above, a perspective view of the cylindrical holder as viewed from below, and a perspective view of a state in which the grating is mounted.

  On the outer periphery of the grating 3 attached to the tip of the cylindrical holder 22 with an adhesive or the like, a plurality of positioning projection plates 22b having a bow shape and a fan-like end face shape from the tip annular end surface 22a of the holder 22 and a column shape are provided. The positioning protrusion 22c protrudes forward. The positioning projection plate 22b is mainly used for positioning the cylindrical holder 22 in the optical axis direction, and the positioning projection 22c is mainly used for positioning the cylindrical holder 22 of the grating 3.

  A plate-like portion 22f as an elastic deformation portion integrally formed from a rear end side peripheral portion of the holder 22 and having an elastic force capable of elastic deformation in the optical axis direction L of the laser beam; A projection 22g having an arcuate surface as an abutting portion that is integrally formed with the plate-like portion and can abut against the apparatus frame 20 is provided. The plate-like portion 22f extends left and right symmetrically toward the outer side in the radial direction from a position at a peripheral portion located symmetrically with respect to the center of the holder 22, and the protrusion 22g is a device of the holder 22. At the time of assembling to the frame 20, it is formed so as to protrude in a direction facing the flat portion 26 a of the wall portion 26.

  Further, the dimension from the tip end portion of the cylindrical holder 22, that is, the front end of the positioning projection plate 22 b to the rear end portion, that is, the front end arc surface of the projection portion 22 g is determined when the cylindrical holder 22 is attached to the cylindrical housing portion 21. The plate-like portion 22f is set to generate an elastic force in the optical axis direction L between the annular end surface 21c of the annular protrusion 21b formed in the front end opening of the housing portion 21 and the flat portion 26a of the wall portion 26. .

(Grating assembly adjustment procedure)
The procedure for adjusting the assembly position of the grating 3 of the light source unit 4 in the optical pickup device 1 of this embodiment configured as described above will be described. The cylindrical holder 22 to which the washer 25 and the grating 3 are attached is inserted in this order from the one end opening 21a of the cylindrical accommodating portion 21, and the position of the grating 3 in the direction of the optical axis L is adjusted. This adjustment can be performed by an operation such as replacing the washer 25 as a positioning spacer with a predetermined thickness. In addition, after inserting the washer 25, when inserting the cylindrical holder 22, the plate-shaped part 22f is inserted in the direction orthogonal to the separating direction of a pair of wall part 26, and it inserts from the slit part 23, and the holder 90 The projection 22g of the plate-like portion 22f is brought into contact with the flat portion 26a of the apparatus frame side accommodating portion with elasticity, and can be attached to the apparatus frame side accommodating portion. That is, the projecting portion 22g as the abutting portion abuts on the flat surface portion 26a and the plate-like portion 22f is elastically deformed, so that the holder 22 or the grating 3 is biased and the annular end surface 21c as the reference surface is pressed. The position of the grating in the optical axis direction is regulated. Further, the edge portion 26 b of the inner wall surface constituting the wall portion 26 is formed in a slope shape, and the plate-like portion 22 f of the cylindrical holder 22 can be smoothly rotated and inserted into the groove-like accommodation portion 27.

  Next, a jig such as an eccentric pin is inserted from the through hole 21e opened in the outer peripheral wall 20a of the cylindrical housing portion 21, and the inner cylindrical holder 22 is rotated about the optical axis L, so that the holder 22 The rotational position of the attached grating 3, that is, the phase is adjusted.

  Here, the cylindrical holder 22 is extended from the rear end side peripheral edge portion and has a plate-like portion 22f having an elastic force that can be elastically deformed in the optical axis direction L of the laser beam, and the plate-like portion formed on the plate-like portion. A projection 22g having an arcuate surface as an abutting portion capable of abutting on the frame 20 is provided, and the flat portion 26a of the wall portion 26 provided on the apparatus frame 20 is formed by the plate-like portion 22f and the projecting portion 22g. Because it is pressed and biased by line contact, the rotation operation can be performed smoothly when adjusting the rotation of the grating. On the other hand, after the rotation adjustment, an elastic (rotation) return force such as a coil spring is generated and the holder rotates. The accuracy of position adjustment is improved without causing a situation. Further, since the holder itself is provided with a plate-like portion having an elastic force, a conventional coil spring or spacer is not required.

  As described above, after the position in the direction along the optical axis L of the grating 3 and the position in the rotation direction around the optical axis L are adjusted, each component is fixed by an adhesive or the like. Thus, the assembling work of the light source unit 4 is completed.

(Main effects of this form)
As described above, in the optical pickup device of this embodiment, since the holder holding the grating itself has an elastic force, a conventional coil spring or spacer that presses and urges the holder becomes unnecessary, and the number of parts can be reduced. .

  Further, in this embodiment, the spring that presses and biases is a plate-like portion that is formed integrally with the holder, so that it is possible to perform stable and highly accurate adjustment without elastic return after rotation adjustment.

Further, since the plate-like portion having the elastic force extends symmetrically from the position at the peripheral portion located symmetrically with respect to the center of the holder toward the outer side in the radial direction, the pressing biasing force is evenly distributed. The optical axis does not tilt. Further, the insertion from the slit portion is facilitated, and the interval between the slit portions may be approximately the diameter size of the cylindrical portion of the holder, and a sufficient contact area (area) with the flat portion of the projection provided on the plate-like portion can be secured. . In addition, since the flat portion is formed to be opposed to the one end opening side of the cylindrical housing portion of the apparatus frame with a gap, the optical axis direction tip portion (light beam emitting side) of the laser light source and the holder plate A space is formed between the laser light source and the laser light source, and the mounting position in the optical axis direction of the laser light source is increased, and the position adjustment in the optical axis direction can be easily performed. In particular, when the protruding portion of the plate-like portion is protruded toward the laser light source, the degree of freedom is further increased.

  Furthermore, since the laser diode is not configured to be loaded by the reaction force that press-fits the holder of the coil spring and presses and urges the holder of the coil spring as in the prior art, the laser is not adjusted during or after adjusting the rotational position of the holder. There is no problem that the rotational position of the diode itself changes due to the reaction force or elastic return force.

(Other embodiments)
In the above embodiment, the holder 22 has a cylindrical shape except for the groove 22e. For example, the holder 22 may have a shape that can be rotated by a predetermined angle range around the optical axis L.

  In the above embodiment, the spherical projection 22g is integrally provided on the plate-like portion 22f. However, for example, the plate-like portion 22f may be separately manufactured from a material having excellent slidability and retrofitted to the plate-like portion. The shape of the tip of the protrusion may also be a spherical surface instead of an arc shape.

  Further, in the above embodiment, the plate-like portion 22f that is elastically deformed in the optical axis direction is extended outward in the radial direction of the holder 22. However, if an opening through which the laser beam is incident can be secured, the plate portion 22f is formed to protrude inward from the peripheral portion of the holder. May be.

  Furthermore, in the above embodiment, the protrusion 22g is brought into contact with the flat portion provided on the device frame 20, but may be brought into contact with the device frame facing surface of the holder 30 of the laser diode 2.

  Moreover, in the said form, although the protrusion part 22g protruded to the laser light source side and was contact | abutted to the plane part, it is also possible to contact | abut to the peripheral part 21d of the one end opening 21a opposite to the said direction.

It is a schematic block diagram which shows the optical system of the optical pick-up apparatus to which this invention is applied. It is the perspective view which looked at the arrangement composition of the light source unit and cylindrical holder of the optical pick-up device to which the present invention is applied from diagonally upward. It is a top view which shows the arrangement configuration of the light source unit and cylindrical holder of the optical pick-up apparatus to which this invention is applied. It is a disassembled perspective view which shows a cylindrical holder which comprises the optical pick-up apparatus to which this invention is applied, a spacer, and a part of apparatus frame. It is sectional drawing which shows the state which mounted | wore the apparatus frame with the cylindrical holder. (A), (b), (c) is the perspective view which looked at the cylindrical holder from diagonally upward, the perspective view which looked at the cylindrical holder from the bottom, and the perspective view of the state which mounted | wore the grating.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical pick-up apparatus 2 Laser diode 3 Grating 4 Light source unit 20 Apparatus frame 21 Holding part 21a One end opening 21b Annular protrusion 21c Annular end surface 21d Peripheral part 21e Through-hole 22 Cylindrical holder 22a End annular end surface 22b Positioning protrusion plate 22c Positioning protrusion 22e Groove 23 Slit (first space)
24 Adhesive 25 Washer 26 Wall part 26a Flat part 27 Groove-shaped accommodation part (second space part)

Claims (7)

A grating that diffracts a laser beam emitted from a laser light source, a cylindrical holder that is fixed to the grating and that is open at both ends, a device frame side housing portion in which the holder is rotatably housed, and the holder In the optical pickup device having a pressing means for pressing and fixing to the device frame side accommodating portion,
An optical pickup apparatus, wherein the pressing means is formed integrally with the holder.   2. The optical pickup device according to claim 1, wherein the pressing means includes an elastic deformation portion that elastically deforms in the optical axis direction of the laser light. 3. The pressing unit according to claim 1, wherein the pressing means is a plate-like portion extending in a radial direction from a peripheral portion of the holder, and a contact formed on the plate-like portion and capable of coming into contact with the device frame side accommodating portion. The apparatus frame side accommodating portion is provided with a reference plane that is orthogonal to the optical axis direction and restricts the position of the grating in the optical axis direction, and a flat portion that faces the reference plane. And
When the abutting portion abuts on the flat surface portion and the plate-like portion is elastically deformed, the holder or the grating abuts on the reference surface in a biased state, and the position of the grating in the optical axis direction is regulated. An optical pickup device.   The optical pickup device according to claim 3, wherein the contact portion is a protruding portion that protrudes from the plate-like portion in the direction of the planar portion.   5. The optical pickup device according to claim 4, wherein the tip of the protruding portion is formed in a circular arc shape.   6. The plate-like portion according to claim 3, wherein the plate-like portion extends symmetrically outwardly from a position at a peripheral portion located point-symmetrically with respect to the center of the holder, and the planar portion is the device. It is comprised from the inner wall surface of a pair of left and right wall portions formed by projecting the first space portions with their front end surfaces facing each other, and the first space portion is the diameter of the cylindrical outer portion of the holder The cylindrical holder is configured to be larger and smaller than the length between both side end portions of the plate-like portion, and constitutes a part of the apparatus frame side housing portion at a position facing the inner wall surface. A holding portion for holding the holder having an inner diameter substantially equal to an outer diameter of the holding portion is provided, and a second space portion between the flat portion and an end surface of the holding portion facing the inner wall surface is defined as the first space. Formed so as to be connected to The optical pickup apparatus according to claim. 7. The optical pickup device according to claim 6, wherein the size of the first space is larger than the outer shape of the case that houses the light emitting element of the laser light source.

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