JP5079482B2 - Optical pickup - Google Patents

Description

  The present invention relates to an optical pickup for recording / reproducing a signal to / from a disk-shaped recording medium (hereinafter abbreviated as a disk) such as a CD or a DVD, and in particular, a support substrate to which a light emitting / receiving unit including a semiconductor laser is attached. The present invention relates to a mounting structure for adhering to a chassis.

  The optical pickup condenses the light beam emitted from the semiconductor laser on the recording surface of the disc by the objective lens, and receives the return light beam from the disc by the photodetector through the objective lens. Can be recorded / reproduced. The objective lens is attached to a lens holder, and this lens holder is movably supported by a holder support portion. Further, an electromagnetic driving means constituted by a magnet, a yoke or the like can drive the lens holder in the focus direction and the tracking direction. A semiconductor laser as a light source and a photodetector for light reception are unitized, and this light emitting / receiving unit is attached to a support substrate. A printed circuit board may be used as the support substrate. In order to efficiently dissipate the heat generated by the semiconductor laser to the outside, a flexible printed circuit board is fixed to one side of the support substrate made of a metal plate. In many cases, a light emitting / receiving unit is mounted. In addition, since the holder support portion, the electromagnetic drive means, the support substrate, and the like are carried by a chassis that is a base, and this chassis can also be used for heat dissipation, a metal chassis such as aluminum die cast is widely used.

  In such an optical pickup assembly process, the support substrate to which the light emitting / receiving unit is attached is bonded and fixed to an attachment surface which is one side surface of the chassis, and an ultraviolet curable resin is generally used as an adhesive in that case. At that time, by positioning the light receiving and emitting unit with respect to a predetermined optical path set on the chassis side by displacing the support substrate in the rotation direction with respect to the mounting surface of the chassis, the support substrate is provided on the mounting surface. An appropriate amount of uncured adhesive (ultraviolet curable resin) is applied to the adhesive reservoir using a dispenser or the like, and thereafter, the adhesive in the adhesive reservoir is cured by irradiating ultraviolet rays.

  FIG. 9 is a perspective view showing a conventional chassis provided in this type of optical pickup. In the drawing, an opening 31 into which a light emitting / receiving unit (not shown) is inserted is provided on one side of the chassis 30, and a predetermined space is provided in an internal space covered by the upper cover 40 on the back side of the opening 31. The optical path is formed. The side surface of the chassis 30 from which the opening 31 is exposed is a mounting surface 32, and a pair of adhesive reservoirs 33 are provided on the mounting surface 32. These adhesive reservoirs 33 are formed as shallow recesses in which a part of the outer edge of the mounting surface 32 is cut out. Then, a support substrate (not shown) to which the light emitting / receiving unit is attached is arranged so as to face the mounting surface 32 of the chassis 30, and the support substrate is positioned and adjusted in the rotation direction, and then uncured in the adhesive reservoir 33. The support substrate is bonded and fixed to the chassis 30 by applying an agent (ultraviolet curable resin) and irradiating the adhesive with ultraviolet rays. As a result, the light emitting / receiving unit attached to the support substrate is held by the chassis 30 in a positioned state.

As another conventional example, there is also known an optical pickup having a structure in which a pair of concave groove-shaped adhesive reservoirs that longitudinally cut the mounting surface of the chassis is provided, and an ultraviolet curable resin is applied to these adhesive reservoirs (for example, , See Patent Document 1).
JP 2001-291272 A

  By the way, in the case of an optical pickup provided with a concave groove-shaped adhesive reservoir that vertically cuts the mounting surface of the chassis as in the conventional example described in Patent Document 1, a support substrate is made to face the mounting surface. In the ultraviolet irradiation process performed in a state where the adhesive is applied near the opening end of the concave groove (ultraviolet curable resin), the central portion in the extending direction of the concave groove can be irradiated with ultraviolet rays. It was difficult to efficiently irradiate the adhesive applied to the surface with ultraviolet rays. Therefore, the adhesive is not sufficiently cured and the required adhesive strength cannot be ensured, and the problem that the productivity is deteriorated due to prolonged irradiation time of ultraviolet rays is likely to occur.

  On the other hand, when the adhesive reservoir 33 is formed as a shallow recess in which a part of the outer edge of the mounting surface 32 of the chassis 30 is cut out as in the conventional example shown in FIG. Since it is possible to efficiently irradiate the adhesive (ultraviolet curable resin) in the reservoir 33 with ultraviolet rays, the required adhesive strength can be ensured. However, since the vicinity of one side along the longitudinal direction of the support substrate is bonded and fixed to the mounting surface 32 of the chassis 30, when the adhesive expands / contracts as the environmental temperature changes, the support substrate is inclined. There was a problem that it was likely to occur. When the support substrate holding the light emitting / receiving unit is tilted with respect to the mounting surface 32 of the chassis 30 as described above, the light receiving / emitting unit is tilted together and the optical axis is tilted. Reproduction characteristics are likely to deteriorate.

  The present invention has been made in view of the actual situation of the prior art, and the object thereof is to easily and reliably bond the support substrate holding the light emitting / receiving unit to the mounting surface of the chassis and to change the environmental temperature. Even so, an object of the present invention is to provide a highly reliable optical pickup capable of suppressing performance degradation caused by the inclination of the light emitting / receiving unit.

According to the present invention, two locations that are substantially point-symmetrical with respect to the light receiving / emitting unit in the vicinity of the center line along the longitudinal direction of the support substrate are formed as adherends, and the chassis to which the support substrate is bonded and fixed is attached. On the surface, there was provided a concave adhesive reservoir facing the adherend portion of the support substrate, and an introduction path extending continuously from the adhesive reservoir to the outer edge of the mounting surface at a recess wider than the adhesive reservoir. . Then, the adhesive reservoir is filled with UV curable resin to bond the mounting surface of the chassis and the support substrate, and the wide introduction path formed at the inlet of the adhesive reservoir is filled with a heat radiation sealing material with excellent thermal conductivity. It was decided to.

  According to the optical pickup of the present invention, the adherend portion of the support substrate that opposes the adhesive reservoir provided on the mounting surface of the chassis is dispersed in a well-balanced manner without being shifted to one end of the support substrate. Even if the adhesive expands and contracts as the environmental temperature changes, the support substrate is less likely to be tilted. Therefore, performance deterioration due to the tilt of the light emitting / receiving unit is less likely to occur, and an improvement in reliability can be expected. In addition, the mounting surface of the chassis is provided with an introduction path that is wider than the adhesive reservoir, and is connected to the adhesive (ultraviolet curable resin) in the adhesive reservoir via the introduction path. On the other hand, since the ultraviolet rays can be efficiently irradiated, the required adhesive strength can be easily secured and the productivity is improved. Furthermore, since the heat on the support substrate side is easily transmitted to the chassis through the heat radiation sealing material filled in the introduction path, the heat radiation effect is enhanced.

According to the present invention, a holder supporting portion that movably supports a lens holder to which an objective lens is attached, an electromagnetic driving means that drives the lens holder, and a light receiving and emitting unit that includes a semiconductor laser are attached to a metal chassis. In the optical pickup, in which the support substrate is bonded to the mounting surface of the chassis with an ultraviolet curable resin, the light emitting / receiving unit near the center line along the longitudinal direction of the support substrate Two locations that are substantially point-symmetrical with respect to each other are formed as adherend portions, a concave adhesive reservoir facing the adherend portion on the mounting surface of the chassis, and wider than the adhesive reservoir. In addition, the adhesive reservoir is provided with an introduction path that continues to the outer edge of the mounting surface, and the adhesive reservoir is filled with the ultraviolet curable resin and is released to the introduction path. And the configuration of filling the use sealant.

In the optical pickup configured in this way, two locations that are in a substantially point-symmetrical positional relationship with the light emitting / receiving unit sandwiched between the center line along the longitudinal direction of the support substrate and are well-balanced are Since these parts to be bonded are bonded by the adhesive filled in the adhesive reservoir on the mounting surface of the chassis, the support substrate can be used even if the adhesive expands or contracts in a high temperature environment or a low temperature environment. Is less likely to tilt with respect to the mounting surface of the chassis. Therefore, this optical pickup is unlikely to deteriorate in performance due to the inclination of the light emitting / receiving unit even if the environmental temperature changes. In addition, the mounting surface of the chassis is provided with an introduction path, which is a recess wider than the adhesive reservoir, and is continuously provided in the adhesive reservoir, and ultraviolet rays are performed with the support substrate facing the mounting surface. In the irradiation step, the adhesive in the adhesive reservoir can be efficiently irradiated with ultraviolet rays through this introduction path, so that the required adhesive strength can be easily ensured without prolonging the irradiation time of the ultraviolet rays. Moreover, since the introduction path is filled with a heat radiation sealing material having excellent thermal conductivity, the heat on the support substrate side can be easily transmitted to the chassis via the heat radiation sealing material, and the heat radiation effect is increased accordingly.

  In the above configuration, the support substrate has a metal plate bonded to the mounting surface of the chassis and a flexible printed circuit board fixed to the metal plate, and the light emitting and receiving unit is mounted on the flexible printed circuit board. Preferably, heat generated by the light emitting / receiving unit (semiconductor laser) can be efficiently radiated through the metal plate of the support substrate.

  An embodiment will be described with reference to the drawings. FIG. 1 is an exploded perspective view of the optical pickup according to the embodiment, FIG. 2 is a perspective view of the optical pickup viewed from the top side, and FIG. 4 is a perspective view of the optical pickup, FIG. 4 is a bottom view of the optical pickup, FIG. 5 is a side view of the optical pickup, and FIG. FIG. 7 is a perspective view showing the chassis of the optical pickup, and FIG. 8 is a side view of the chassis.

  The optical pickup shown in these drawings includes a chassis 1 made of metal such as an aluminum die-cast, a holder support portion and electromagnetic driving means, which will be described later, carried on the chassis 1, and supported movably on the holder support portion. An objective lens 3 attached to the lens holder 2 to be used, a collimator lens (not shown), a semiconductor laser serving as a light source, and a light receiving / emitting unit 4 formed as a unit, and holding the light receiving / emitting unit 4 Then, a support substrate 5 bonded and fixed to the mounting surface 1a of the chassis 1 and a flexible printed circuit board (hereinafter referred to as FPC) in which an extension portion 6a is fixed to the support substrate 5 connected to an optical disc player (not shown) on the set side. 6), a reflection mirror 7 fixed to the inner bottom of the chassis 1 directly below the objective lens 3, and an aluminum press-contacted to the back surface 4a of the light emitting / receiving unit 4. A heat sink (heat sink) 8 made of a metal, a metal presser spring 9 that elastically biases the heat sink 8 toward the light emitting / receiving unit 4, and an upper cover 10 that covers a part of the internal space on the chassis 1. Etc. are mainly composed. The holder support portion includes a plurality of conductive wires 11 that elastically support the lens holder 2, a support member 12 through which each wire 11 is inserted, and the like. The electromagnetic drive means is composed of a magnet 13 and a yoke, and can drive the objective lens 3 in the focus direction and tracking direction of a disc such as a DVD. Each wire 11 also used for energizing the electromagnetic drive means is electrically connected to the FPC 6, and the light emitting / receiving unit 4 is mounted on the extending portion 6a of the FPC 6.

  A rectangular through hole 5a is formed at the center of the support substrate 5, and a notch 5b for engaging a jig (not shown) for position adjustment is formed at one corner of the support substrate 5. . The support substrate 5 is composed of a laminated structure in which the extending portion 6a of the FPC 6 is fixed to one surface of a metal plate, and the terminal portion 4b of the light emitting / receiving unit 4 is soldered to the extending portion 6a of the FPC 6, thereby receiving and emitting light. The unit 4 is integrated with the support substrate 5. The other surface of the support substrate 5 is bonded and fixed to a mounting surface 1 a that is one side surface of the chassis 1, and the tip of the light emitting / receiving unit 4 passes through the through hole 5 a and is inserted into the opening 1 b of the chassis 1.

  The mounting structure of the support substrate 5 will be described in detail. Of the other surface of the support substrate 5 (the surface facing the mounting surface 1a), the light receiving / emitting unit 4 is sandwiched in the vicinity of the center line along the longitudinal direction. Two places which are in a symmetrical positional relationship are made to be bonded portions 5c (see FIG. 1). The mounting surface 1a of the chassis 1 is provided with a pair of recessed portions 15 that are located across the opening 1b and open on the bottom surface side. The recessed portion 15 includes an adhesive reservoir 15a that is a cylindrical recess facing the bonded portion 5c, and a rectangular column-shaped recess that is wider than the adhesive reservoir 15a, and is continuously attached to the adhesive reservoir 15a. It is formed in a two-stage structure including an introduction path 15b that reaches the outer edge (lower edge) of the. Then, as shown in FIG. 8, after the uncured adhesive (ultraviolet curable resin) 16 is filled in the adhesive reservoir 15a, the adhesive 16 is cured, and the support substrate 5 is bonded and fixed to the mounting surface 1a. The introduction path 15b is filled with a heat radiation sealing material 17.

  That is, the support substrate 5 to which the light emitting / receiving unit 4 is attached is aligned and bonded to the mounting surface 1 a of the chassis 1. At that time, the tip of the light emitting / receiving unit 4 is first inserted into the opening 1 b of the chassis 1. Then, the support substrate 5 is disposed opposite to the mounting surface 1a, and in this state, a jig (not shown) is engaged with the notch 5b of the support substrate 5 to displace the support substrate 5 in the rotational direction with respect to the mounting surface 1a. By doing so, the light emitting / receiving unit 4 is positioned and adjusted with respect to a predetermined optical path set on the chassis 1 side. Next, an appropriate amount of uncured adhesive (ultraviolet curable resin) 16 is filled into the adhesive reservoir 15a provided on the mounting surface 1a using a dispenser or the like, and then the gap between the chassis 1 and the support substrate 5 is filled. The entrance part of the exposed recessed part 15 is irradiated with ultraviolet rays to cure the adhesive 16 existing in the inner part of the recessed part 15. That is, the support substrate 5 holding the light emitting / receiving unit 4 is attached to the chassis 1 by irradiating the adhesive 16 in the adhesive reservoir 15a with ultraviolet rays through the relatively wide introduction path 15b and curing the adhesive 16. Are fixed to the mounting surface 1a in a positioning state. Thereafter, the heat radiation sealing material 17 is filled into the introduction path 15b using a dispenser or the like and cured. However, since the heat radiation sealing material 17 has an appropriate elasticity even after curing, there is no risk of stressing the support substrate 5 even if the environmental temperature changes.

  The presser spring 9 is fixed to the chassis 1 in a cantilevered manner using screws 18, and the heat radiating member 8 is in surface contact with the back surface 4 a of the light emitting / receiving unit 4 by the biasing force of the presser spring 9. Heat generated by the semiconductor laser of the light emitting unit 4 can be efficiently radiated through the radiator 8. Reference numeral 19 in the figure denotes an engagement piece that is screwed to the chassis 1 and engages with a guide shaft of an optical disk player (not shown) in a resilient contact state. The optical pickup is transferred along the guide shaft. It has come to be.

  In the optical pickup configured as described above, the light beam emitted from the semiconductor laser of the light receiving and emitting unit 4 and converted into a parallel light beam by the collimating lens is reflected by the reflection mirror 7 on the inner bottom portion of the chassis 1, The light is condensed on the recording surface of the disk by the objective lens 3 positioned directly above. Further, the return light beam from the disk is transmitted through the objective lens 3, reflected right by the reflection mirror 7, and received by the photodetector of the light receiving / emitting unit 4.

  As described above, in the optical pickup according to the present embodiment, a substantially point-symmetrical region sandwiching the light emitting / receiving unit 4 in the vicinity of the center line along the longitudinal direction of the support substrate 5 is a pair of adherends. 5c, and these bonded portions 5c are bonded by the adhesive 16 filled in the adhesive reservoir 15a of the mounting surface 1a of the chassis 1, so that the cured adhesive 16 is in a high temperature environment or a low temperature environment. The support substrate 5 is less likely to be inclined with respect to the mounting surface 1a even if it is expanded or contracted. Therefore, this optical pickup is less likely to deteriorate in performance due to the inclination of the light emitting / receiving unit 4 even if the environmental temperature changes. In addition, an introduction path 15b, which is a recess wider than the adhesive reservoir 15a, is continuously provided on the mounting surface 1a of the chassis 1 so that the support substrate 5 faces the mounting surface 1a. In the ultraviolet irradiation process performed in the above-described state, the adhesive 16 in the adhesive reservoir 15a can be efficiently irradiated with ultraviolet rays through the introduction path 15b, so that it is necessary even if the ultraviolet irradiation time is not prolonged. Adhesive strength can be easily secured. Moreover, since the introduction path 15b is filled with the heat radiation sealing material 17 having excellent thermal conductivity, the heat on the support substrate 5 side can be easily transmitted to the chassis 1 through the heat radiation sealing material 17, and the heat radiation is correspondingly increased. Increases effectiveness.

  In the above embodiment, the introduction path 15b is a quadrangular prism-shaped recess in order to increase the filling amount of the heat radiation sealing material 17, but the introduction path 15b has another shape, for example, a funnel-shaped recess. May be. Moreover, the formation position of the adhesive reservoir 15a facing the adherend portion 5c of the support substrate 5 can also be selected as appropriate. In short, the light receiving and emitting unit 4 is sandwiched near the center line along the longitudinal direction of the support substrate 5. If the adherends 5c are dispersed in two positions in a well-balanced manner, the tilt of the support substrate 5 that is a concern in a high and low temperature environment can be effectively suppressed.

It is a disassembled perspective view of the optical pick-up which concerns on an Example. It is the perspective view which looked at this optical pick-up from the top side. It is the perspective view which looked at this optical pick-up from the bottom side. It is a bottom view of the optical pickup. It is a side view of the optical pickup. It is a side view of this optical pick-up which shows the state which exposed the back surface of the light emitting / receiving unit. It is a perspective view which shows the chassis of this optical pick-up. It is a side view of this chassis. It is a perspective view which shows the chassis of the optical pick-up which concerns on a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Chassis 1a Mounting surface 2 Lens holder 3 Objective lens 4 Light emitting / receiving unit 5 Support substrate 5a Through-hole 5b Notch 5c Adhered part 6 Flexible printed circuit board 6a Extension part 7 Reflection mirror 8 Radiator 9 Holding spring 11 Wire (Holder support) Part)
13 Magnet (Electromagnetic drive means)
15 Recessed portion 15a Adhesive reservoir 15b Introduction path 16 Adhesive (UV curable resin)
17 Heat radiation sealing material

Claims (2)

A holder supporting part for movably supporting a lens holder to which an objective lens is attached to a metal chassis, electromagnetic driving means for driving the lens holder, and a support substrate to which a light emitting / receiving unit including a semiconductor laser is attached In the optical pickup in which the support substrate is bonded to the mounting surface of the chassis with an ultraviolet curable resin,
Two locations that are substantially point symmetrical with respect to the light receiving / emitting unit in the vicinity of the center line along the longitudinal direction of the support substrate are defined as the adherend, and the attachment portion of the chassis includes the adherend. A concave adhesive reservoir opposite to the adhesive reservoir, and an introduction path extending continuously from the adhesive reservoir to the outer edge of the mounting surface at a recess wider than the adhesive reservoir, and the ultraviolet ray curing is provided in the adhesive reservoir. An optical pickup characterized in that it is filled with resin and the introduction path is filled with a heat radiation sealing material.   2. The support board according to claim 1, wherein the support board includes a metal plate bonded to the mounting surface of the chassis, and a flexible printed board fixed to the metal board, and the light emitting and receiving unit is provided on the flexible printed board. An optical pickup characterized by being mounted.

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