JP4030526B2 - Optical pickup - Google Patents

Description

  The present invention relates to an optical pickup for recording / reproducing information on / from a disc such as a CD (compact disc) or a DVD (digital versatile disc), and more particularly to a heat dissipation measure for a light emitting / receiving unit in which a semiconductor laser or the like is incorporated. .

  An optical pickup generally drives a light receiving / emitting unit in which a light emitting means such as a semiconductor laser and a light receiving means such as a photodetector are integrally disposed, a lens holder to which an objective lens is attached, and the lens holder. An actuator provided with electromagnetic driving means, an upper cover containing the actuator with the objective lens exposed, a reflection mirror installed in an optical path between the light emitting / receiving unit and the objective lens, and each of these members It is roughly configured with a mounted chassis. This type of optical pickup is used by being incorporated in a disk player such as a CD player, and a light beam emitted from a semiconductor laser or the like and reflected by a reflecting mirror is condensed on the recording surface of the disk by an objective lens. The return light beam from the disk is received by the light receiving means via the objective lens and the reflection mirror.

  FIG. 9 is an exploded perspective view showing a conventional example of such an optical pickup, FIG. 10 is a plan view of an actuator provided in the optical pickup, and FIG. 11 is a cross-sectional view of the actuator (see, for example, Patent Document 1). The conventional optical pickup shown in these drawings includes a chassis 1 made of a metal material such as aluminum, and an actuator 2 made up of an objective lens 3, a lens holder 4, a wire 5, a support member 6, a magnet 7, a base member 8, and the like. The light receiving / emitting unit (hologram unit) which is formed by unitizing the upper cover 9 having the opening 9a for exposing the objective lens 3 and enclosing the actuator 2 and the semiconductor laser and the photodetector. ) 10 and a reflection mirror 11 installed in the optical path between the light emitting / receiving unit 10 and the objective lens 3.

  The chassis 1 is reciprocated in the radial direction of the disk along a guide shaft (not shown), and a reflection mirror 11 is fixed at a substantially central position of the bottom plate portion of the chassis 1 at an attachment angle of 45 degrees. The light emitting / receiving unit 10 is incorporated in the opening 1a of the chassis 1 facing the reflecting mirror 11, and the back side of the light emitting / receiving unit 10 is covered with a sheet metal heat radiation cover 12. Each terminal of the light receiving / emitting unit 10 is connected to a reinforcing portion attached to the support plate 14 of the flexible wiring board 13, and the light receiving / emitting unit is connected via a wiring pattern formed on the flexible wiring board 13. 10 is electrically connected to a signal processing circuit (not shown). The heat radiating cover 12 is fixed to one side of the chassis 1 with fixing screws 15, and the reinforcing portion of the flexible wiring board 13 is sandwiched between the heat radiating cover 12 and the side wall of the chassis 1. . The light beam emitted from the light emitting / receiving unit 10 is reflected in the vertical direction by the reflecting mirror 11 through the opening 1a, and the return light beam is reflected in the horizontal direction by the reflecting mirror 11, and then passes through the opening 1a. Light is received by the light receiving / emitting unit 10.

  The actuator 2 includes a lens holder 4 to which an objective lens 3 is attached and coils (not shown) (a focus coil and a tracking coil) are wound, and a plurality of conductive members for elastically supporting the lens holder 4. A wire 5, a support member 6 through which the base end side of each wire 5 is inserted, and a land portion for connecting the base end portion of each wire 5 are formed and fixed to the surface of the support member 6 on the side opposite to the lens holder 4. And the base member 8 also serving as a yoke on which the support member 6 and the magnet support member 17 are mounted and fixed. The objective lens 3 is located immediately above the reflecting mirror 11. Each wire 5 has one end portion (free end portion) soldered to the coil, and the other end portion (base end portion) penetrates the back substrate 16 and is soldered to the land portion. Since the substrate 16 is electrically connected to a drive control circuit (not shown), a drive current is supplied to the focus coil and the tracking coil via each wire 5. The magnet 7 generates a magnetic flux in a direction crossing the direction of the current flowing through the coil, and the coil, the magnet 7, the base member 8 and the like constitute an electromagnetic drive means. The lens holder 4 is driven in the focus direction and tracking direction of the disk by the drive current supplied to the wire 5 during the correction operation of the objective lens 3.

The actuator 2 is placed on the bottom plate portion of the chassis 1, and an attachment screw 19 inserted through the coil spring 18 is screwed into the chassis 1 from above the base member 8, and two adjustment screws 20 are placed below the chassis 1. Then, the base member 8 is fixed to the chassis 1 in a state where the optical axis of the objective lens 3 is adjusted. In other words, in order to accurately record / reproduce signals with respect to the recording surface of the disc, the optical axis of the objective lens 3 positioned immediately above the reflecting mirror 11 is set perpendicular to the recording surface of the disc. Therefore, when the actuator 2 is mounted on the chassis 1, the optical axis of the objective lens 3 can be adjusted by adjusting the tightening force of the adjusting screw 20.
JP 2001-319342 A (page 2-3, FIG. 9)

  By the way, in this type of optical pickup, the chassis 1 made of a metal material has become a factor that hinders weight reduction and cost reduction. Recently, optical pickups have been proposed that use a synthetic resin chassis to reduce weight and reduce costs. However, a synthetic resin chassis has a heat dissipation effect compared to a chassis made of a metal material such as aluminum. Therefore, if the chassis is simply made of synthetic resin, the heat generated by the light emitting / receiving unit cannot be efficiently radiated to the outside. In other words, since the light emitting / receiving unit equipped with a semiconductor laser or the like is a heat generation source, heat dissipation measures are indispensable to ensure the reliability of the optical pickup, and when the internal temperature rises excessively due to insufficient heat dissipation, for example, There is a problem that the life of the semiconductor laser is shortened.

  The present invention has been made in view of the actual situation of the prior art, and its purpose is to efficiently use the heat generated by the light emitting and receiving unit while reducing the weight and cost by using a synthetic resin chassis. An object of the present invention is to provide a highly reliable optical pickup that can dissipate heat to the outside.

  In the present invention, a groove is provided in the vicinity of a mounting surface of a chassis molded from a synthetic resin, and a metal heat dissipating plate having a screw hole is inserted into the groove, and a fixing screw is inserted into the groove from the mounting surface of the chassis to dissipate heat. The light emitting / receiving unit is fixed to the mounting surface of the chassis by being screwed into the screw hole of the plate. If it does in this way, the heat | fever which generate | occur | produces in a light receiving / emitting unit can be efficiently conducted to a heat sink via a fixing screw etc., aiming at weight reduction and cost reduction using the chassis made from a synthetic resin.

  In the optical pickup according to the present invention, a groove is provided in the vicinity of the mounting surface of the synthetic resin chassis, a metal heat sink having a screw hole is inserted into the groove, and a fixing screw is inserted into the groove from the mounting surface of the chassis. Since the light emitting / receiving unit is fixed to the mounting surface of the chassis by screwing it into the screw hole of the heat sink, the heat generated by the light receiving / emitting unit is efficiently conducted to the heat sink with a large heat capacity via the fixing screw etc. It becomes possible to make it. Therefore, it is possible to provide a highly reliable optical pickup capable of efficiently radiating the heat generated in the light emitting / receiving unit to the outside while reducing the weight and cost by using a synthetic resin chassis. it can.

  The present invention includes a lens holder to which an objective lens is attached, a holder support portion that movably supports the lens holder, electromagnetic drive means that drives the lens holder during correction operation of the objective lens, and at least the holder support And a synthetic resin chassis on which the electromagnetic driving means is mounted, a light emitting means for emitting a light beam to the disk via the objective lens, and a light receiving means for receiving a return light beam from the disk. And a light receiving and emitting unit, wherein the light receiving and emitting unit is supported on the mounting surface of the chassis, and a groove is provided in the chassis, and a screw insertion hole communicating with the groove is exposed to the mounting surface. And insert a metal heat sink having a screw hole in the groove, and release the fixing screw inserted through the screw insertion hole. By screwing the screw hole of the plate, and constituting said light receiving and emitting unit so as to fix to the mounting surface of the chassis.

  In the optical pickup configured in this way, the light emitting / receiving unit can be positioned with high accuracy with respect to the mounting surface of the chassis while reducing the weight and cost by using a synthetic resin chassis. The heat generated in the step can be efficiently conducted to the heat radiating plate via a fixing screw or the like, and the adjustment of the mounting position of the light emitting / receiving unit (adjustment of the rotation direction) performed at the final stage of assembly is facilitated.

  In the above configuration, the heat radiating plate has a flat plate portion and an upright portion bent at a substantially right angle with respect to the flat plate portion. The upright portion is inserted into the groove portion of the chassis, and the flat plate portion is exposed to the outside of the chassis. If such a heat sink is used, even if a large heat sink is arranged on the chassis, the overall size of the optical pickup is hardly changed. Therefore, the heat dissipation effect is enhanced by incorporating a heat sink having a large heat capacity. be able to.

  In the above configuration, when the light emitting / receiving unit is covered with a sheet metal cover and both the light emitting / receiving unit and the cover are fixed to the mounting surface of the chassis by the fixing screw, the ground pattern derived from the light emitting / receiving unit is made of sheet metal. The fixing screw can be screwed into the screw hole of the heat radiating plate in a state where the cover is pressed against the cover and the cover is pressed against the head of the fixing screw. It can be efficiently conducted to the heat sink through a cover, a fixing screw, or the like.

  Moreover, in said structure, it is preferable that the said heat sink consists of metal materials, such as aluminum with favorable heat conductivity, from a viewpoint of improving the heat dissipation effect.

  1 is a perspective view of an optical pickup according to an embodiment of the present invention, FIG. 2 is a top view of the optical pickup, and FIG. 4 is a longitudinal sectional view taken along line BB in FIG. 2, FIG. 5 is a side view of the optical pickup, and FIG. 6 is a perspective view of the lower surface side of the optical pickup. 7 is an exploded perspective view of the optical pickup, and FIG. 8 is a cross-sectional view of the optical pickup. The parts corresponding to those in FIGS. Omitted.

  1 to 8 includes a synthetic resin chassis 21, an objective lens 3, a lens holder 4, a wire 5, a support member 6, a magnet 7, a base member 8, and the like, an objective lens, and the like. An upper cover 9 having an opening 9a that exposes the actuator 3 and enclosing the actuator 2, and a light emitting / receiving unit (hologram unit) 10 that is formed by unitizing a semiconductor laser and a photodetector and is fixed to one side of the chassis 21. The flexible wiring board 13 supported by the support plate 14 in the vicinity of the light emitting / receiving unit 10, the reflection mirror 11 installed in the optical path between the light receiving / emitting unit 10 and the objective lens 3, and a plurality of upright portions 22 a A metal heat dissipating plate 22 attached to the bottom of the chassis 21, a sheet metal heat dissipating cover 12 covering the light emitting / receiving unit 10, and a light receiving / emitting unit. It is schematically configured to Tsu preparative 10 and heat radiation cover 12 by a fixing screw 15 that secures the pair of upright portions 22a of the radiator plate 22. That is, in this optical pickup, a synthetic resin chassis 21 is used for weight reduction and cost reduction, and a heat radiating plate 22 is attached to enhance the heat radiating effect, and the heat radiating cover 12 and the fixing screw. The point that heat is conducted from 15 etc. is greatly different from the conventional example shown in FIGS.

  The chassis 21, which is a resin molded product, is reciprocated in the radial direction of the disk along a guide shaft (not shown), and the reflection mirror 11 (see FIG. 3) is 45 degrees at the center of the bottom plate portion of the chassis 21. The mounting angle is fixed. As shown in FIG. 7, one side of the chassis 21 is a mounting surface 21d of the support plate 14 on which the light emitting / receiving unit 10 is mounted, and an opening 21a communicating with the reflecting mirror 11 is formed on the mounting surface 21d. Has been. Further, a pair of screw insertion holes 21c are formed in the attachment surface 21d at a position sandwiching the opening 21a, and a protruding reference surface 21e is formed around the opening 21a. Further, as shown in FIGS. 6 and 8, the bottom portion of the chassis 21 is formed with groove portions 21b at four locations. Of these four groove portions 21b, a pair of groove portions 21b located in the vicinity of the mounting surface 21d. Are respectively communicated with the screw insertion holes 21c.

  The heat radiating plate 22 is made of a metal having good thermal conductivity such as aluminum. As shown in FIG. 7, the heat radiating plate 22 has upright portions 22a bent substantially at right angles from four positions of the flat plate portion 22d. The portion 22a is fitted into each groove portion 21b formed at the bottom of the chassis 21. Further, of these four raised portions 22a, screw holes 22b are formed in both raised portions 22a fitted into the pair of groove portions 21b located in the vicinity of the mounting surface 21d of the chassis 21, and the fixing screw 15 serves as a heat dissipation cover. 12, the flexible wiring board 13, the support plate 14 and the like are inserted into the screw insertion hole 21c, and the fixing screw 15 is screwed into the screw hole 22b of the standing part 22a in the groove 21b.

  The light emitting / receiving unit 10 is fitted and positioned in the opening 21a of the chassis 21. At this time, the peripheral edge of the light emitting / receiving unit 10 hits a reference surface 21e formed around the opening 21a, thereby receiving and receiving. The interval (distance in the optical axis direction) between the light emitting unit 10 and the reflecting mirror 11 is set with high accuracy (see FIG. 8). Each terminal of the light emitting / receiving unit 10 is connected to a portion of the flexible wiring board 13 that is adhered to the support plate 14 and reinforced, and the flexible wiring board 13 includes a signal (not shown). A wiring pattern for electrical connection with the processing circuit is formed, and the peripheral portion of the through hole 13a for inserting the fixing screw 15 is a ground pattern led out from the light emitting / receiving unit 10.

  The heat radiating cover 12 covers the light emitting / receiving unit 10. The heat radiating cover 12 has a through hole 12 a for inserting the fixing screw 15, a belt-like elastic piece 12 b elastically contacting the back surface of the light receiving / emitting unit 10, and a heat radiating plate. An inclined tip end portion 12c that elastically contacts with 22 is provided. Here, the belt-like elastic piece 12b and the inclined tip portion 12c are for conducting heat generated in the light emitting / receiving unit 10 to the heat radiating cover 12 and radiating the heat to the outside. Then, by fastening the fixing screw 15 inserted through the through holes 12a and 13a and the screw insertion hole 21c into the screw hole 22b of the upright portion 22a, as shown in FIGS. 3 and 4, the flexible wiring board 13 and the support plate 14 are provided. The heat radiation cover 12 is fixed to the mounting surface 21d of the chassis 21 with the sandwiched between the belt-shaped elastic piece 12b and the back surface of the light emitting / receiving unit 10, and the inclined tip portion 12c is a chamfered portion 22c of the heat radiation plate 22 (FIG. 7). See).

  Thereby, since the flexible wiring board 13 is pressure-bonded to the mounting surface 21d via the support plate 14, the light emitting / receiving unit 10 integrated with the flexible wiring board 13 and the reflection mirror 11 integrated with the chassis 21 are provided. The interval is maintained with high accuracy. Further, by fastening the fixing screw 15 to the screw hole 22b of the upright portion 22a, the head 15a of the fixing screw 15, the peripheral portion of the through hole 12a of the heat radiation cover 12, and the peripheral portion of the through hole 13a of the flexible wiring board 13 are pressed against each other. Therefore, the heat generated in the light emitting / receiving unit 10 can be conducted to the fixing screw 15 via the heat dissipation cover 12 and the ground pattern, and further efficiently transferred to the heat dissipation plate 22 via the fixing screw 15. Can be conducted. Further, since heat is directly conducted from the inclined front end portion 12c of the heat radiation cover 12 to the heat radiation plate 22, the heat radiation effect is further enhanced. The light beam emitted from the light receiving / emitting unit 10 passes through the opening 21a and is reflected by the reflecting mirror 11 in the vertical direction. The return light beam is reflected by the reflecting mirror 11 in the horizontal direction and then passes through the opening 21a. The light is received by the light emitting / receiving unit 10.

  The actuator 2 includes a lens holder 4 to which an objective lens 3 is attached and coils (not shown) (a focus coil and a tracking coil) are wound, and a plurality of conductive members for elastically supporting the lens holder 4. A wire 5, a support member 6 through which the base end side of each wire 5 is inserted, and a land portion for connecting the base end portion of each wire 5 are formed and fixed to the surface of the support member 6 on the side opposite to the lens holder 4. The back substrate 16 and a base member 8 to which a pair of magnets 7 are attached to serve as a yoke and the support member 6 is mounted and fixed. Located on the top. Each wire 5 has one end portion (free end portion) soldered to the coil, and the other end portion (base end portion) penetrates the back substrate 16 and is soldered to the land portion. Since the substrate 16 is electrically connected to a drive control circuit (not shown), a drive current is supplied to the focus coil and the tracking coil via each wire 5. In this embodiment, each wire 5, the support member 6, and the back substrate 16 constitute a holder support portion that supports the lens holder 4 so as to be elastically movable. The magnet 7 generates a magnetic flux in a direction crossing the direction of the current flowing through the coil, and the coil, the magnet 7, the base member 8 and the like constitute an electromagnetic drive means. The lens holder 4 is driven in the focus direction and tracking direction of the disk by the drive current supplied to the wire 5 during the correction operation of the objective lens 3.

  Thus, in the optical pickup according to the present embodiment, the groove portion 21b is provided in the vicinity of the mounting surface 21d of the synthetic resin chassis 21, and the standing portion 22a of the heat radiating plate 22 made of a metal material having good thermal conductivity is provided as the groove portion 21b. And the fixing screw 15 is inserted into the screw insertion hole 21c from the mounting surface 21d of the chassis 21 and screwed into the screw hole 22b of the upright portion 22a. Since the cover 12 and the like are fixed to the mounting surface 21d of the chassis 21, the heat generated by the light emitting / receiving unit 10 is transferred to the heat radiating plate 22 having a relatively large heat capacity via the heat radiating cover 12, the ground pattern, the fixing screw 15 and the like. It is possible to conduct efficiently. Further, in this optical pickup, since the fixing screw 15 is screwed to the upright portion 22a inserted into the groove portion 21b, the light emitting / receiving unit 10 can be attached on the basis of the outer surface of the chassis 21, and the positioning accuracy is improved. It has become easier. Furthermore, when adjusting the mounting position of the light emitting / receiving unit 10 performed at the final stage of assembly (when adjusting the rotation direction), it is only necessary to loosen the fixing screw 15 and rotate the support plate 14 by a small angle. Since there is no possibility that the distance between the light emitting / receiving unit 10 and the reflecting mirror 11 is positioned by the opening 21a of the chassis 21, the adjustment work can be easily performed. Moreover, even if the slightly larger heat sink 22 is arranged at the bottom of the chassis 21 as described above, the size of the entire optical pickup is hardly changed. Therefore, according to the present embodiment, it is possible to obtain an excellent optical pickup that can be expected to have a sufficient heat radiation effect and has high reliability while using the synthetic resin chassis 21 to reduce the weight and cost.

  In the above embodiment, the moving coil type optical pickup in which the electromagnetic driving means is constituted by a coil wound around the lens holder or a magnet fixed to the base member has been described. The present invention can also be applied to a moving magnet type optical pickup in which an electromagnetic driving means is constituted by a magnet fixed to a holder or a coil fixed to a base member.

It is a perspective view of the upper surface side of the optical pickup according to the example. It is a top view of the optical pickup It is a longitudinal cross-sectional view which follows the AA line of FIG. It is a longitudinal cross-sectional view which follows the BB line of FIG. It is a side view of the optical pickup. It is a perspective view of the lower surface side of the optical pickup. It is a disassembled perspective view of this optical pick-up. It is a cross-sectional view of the optical pickup. It is a disassembled perspective view of the optical pick-up concerning a prior art example. It is a top view of the actuator with which this optical pick-up is equipped. It is sectional drawing of this actuator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 Actuator 3 Objective lens 4 Lens holder 5 Wire 6 Support member 7 Magnet 8 Base member 10 Light emitting / receiving unit 11 Reflection mirror 12 Radiation cover 12a, 13a Through-hole 12b Strip | belt-shaped elastic piece 12c Inclined front-end | tip 13 Flexible wiring board 14 Support plate 15 Fixed Screw 16 Rear substrate 21 Chassis 21a Opening 21b Groove 21c Screw insertion hole 21d Mounting surface 21e Reference surface 22 Heat sink 22a Standing portion 22b Screw hole 22d Flat plate portion

Claims (4)

A lens holder to which an objective lens is attached, a holder support portion that movably supports the lens holder, electromagnetic driving means that drives the lens holder during correction operation of the objective lens, at least the holder support portion and the electromagnetic A synthetic resin chassis on which driving means is mounted; a light emitting / receiving unit provided with light emitting means for emitting a light beam to the disk via the objective lens; and a light receiving means for receiving a return light beam from the disk; In an optical pickup in which the light emitting and receiving unit is supported on the mounting surface of the chassis,
The chassis is provided with a groove, a screw insertion hole communicating with the groove is exposed to the mounting surface, a metal heat sink having a screw hole formed in the groove is inserted, and the screw is inserted through the screw insertion hole. An optical pickup characterized in that the light emitting / receiving unit is fixed to the mounting surface of the chassis by screwing a fixing screw into the screw hole of the heat radiating plate.   2. The heat sink according to claim 1, wherein the heat radiating plate has a flat plate portion and an upright portion bent at a substantially right angle with respect to the flat plate portion. The upright portion is inserted into the groove portion, and the flat plate portion is inserted into the chassis. An optical pickup characterized by being exposed outside.   3. The optical system according to claim 1, wherein the light emitting / receiving unit is covered with a sheet metal cover, and the light receiving / emitting unit and the cover are fixed to the mounting surface of the chassis by the fixing screw. pick up. 4. The optical pickup according to claim 1, wherein the heat radiating plate is made of a metal material having good thermal conductivity.

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