JP2009043325A - Optical pickup and optical recording/reproducing device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To raise heat radiation of an optical component mounted on an optical pickup. <P>SOLUTION: The housing 11 of the optical pickup is covered with a metal cover 23 for protecting an optical component 30. The optical component 30 is bonded and fixed to a predetermined position of the bottom surface of the housing 11, and the upper part of the optical component 30 is covered with the metal cover 23. A heat-conductive resin 31 is disposed between the upper surface 30u of the optical component 30 and the metal cover 23. Thus, when the optical component 30 is connected to the metal cover 23 with the heat-conductive resin 31, even if a heat loss of a laser beam causes heat generation in the optical component 30, the heat is relieved through the heat-conductive resin 31 to the metal cover 23. Thus, heat radiation of the optical component 30 can be improved. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical pickup, and more particularly to a heat dissipation structure for optical components in an optical pickup. The present invention also relates to an optical recording / reproducing apparatus using this optical pickup.

  An optical recording / reproducing apparatus that records and reproduces data on an optical disc such as a CD, DVD, or Blu-ray disc includes an optical pickup, and a heat-generating component such as a laser light source is mounted on the optical pickup. This heat has an adverse effect not only on the characteristics of the laser light source itself but also on other optical components.

In order to prevent the characteristics of the optical component from being changed by heat from the outside, for example, Patent Document 1 provides a holder for holding the optical component, and this holder or the optical component is attached to the pickup housing at a plurality of locations in the circumferential direction. It is disclosed that the temperature distribution of the optical component is made uniform by bringing it into contact. Patent Document 2 discloses that an intermediate member having a higher thermal conductivity than the bobbin is provided between the objective lens and the bobbin to make the temperature distribution in the circumferential direction of the objective lens uniform. .
JP 2006-120206 A JP 2004-110984 A

  In the optical pickup, heat loss occurs not only when the laser light source itself generates heat but also when the laser light passes through the optical component, thereby causing the optical component to generate heat. For example, a beam splitter has a function of transmitting or reflecting a part of incident laser light, and most of the remaining light is reflected or dispersed, but a part of the remaining light is absorbed and changed to heat. It has the property of easily generating heat. Furthermore, since the optical component is accommodated in the housing of the optical pickup and covered with a metal cover, heat tends to be trapped. Since there are a plurality of such optical components in the housing, the optical components in the housing become even higher in temperature, which may adversely affect the characteristics of the optical components such as refractive index fluctuations.

  Accordingly, an object of the present invention is to provide an optical pickup capable of improving the heat dissipation of an optical component. Another object of the present invention is to provide an improved optical recording / reproducing apparatus using such an optical pickup.

  The above object of the present invention is achieved by an optical pickup comprising: an optical component; a heat radiating member facing at least one surface of the optical component; and a heat conductive material that connects the optical component and the heat radiating member. In this case, the optical component is preferably a dichroic prism, a beam splitter, or a half mirror. Moreover, it is preferable that the heat conductive material adheres to a surface different from the laser light incident / exit surface and the reflective surface among the plurality of surfaces of the optical component.

  The optical pickup according to the present invention preferably further includes a housing for housing the optical component, a metal cover attached to the opening of the housing, and the heat dissipation member is a metal cover. According to this, the metal cover used for protection of an optical component can be used also as a heat radiating member, and the heat dissipation of the optical component can be enhanced without increasing the number of components.

  The above object of the present invention can also be achieved by an optical recording / reproducing apparatus including the above optical pickup.

  Thus, according to the present invention, the heat dissipation of the optical component can be improved, and a highly reliable optical pickup can be configured. Further, according to the present invention, a highly reliable optical recording / reproducing apparatus using such an optical pickup can be realized.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic perspective view showing a configuration of an optical pickup according to a preferred embodiment of the present invention.

  As shown in FIG. 1, the optical pickup 100 includes a housing 11, an objective lens driving device 12 (not shown) provided on one main surface side of the housing 11, and a control board. An optical component housing portion 11A is formed on the main surface side. The objective lens driving device 12 is equipped with an objective lens for converging the laser beam on the disk surface.

  The first and second laser diodes 14 and 15 attached to the side surface of the housing 11 and the first and second laser diodes 14 and 15 provided in the optical component housing portion 11A corresponding to the first and second laser diodes 14 and 15, respectively. A dichroic prism 18 that transmits the laser light from the second diffraction gratings 16 and 17 and the first laser diode 14 and reflects the laser light from the second laser diode 15, and a reflection from an optical disk (not shown). A deflection beam splitter 19 (hereinafter simply referred to as a beam splitter) that guides light to the photodiode 22 side, a rising mirror 20 that changes the traveling direction of the laser light, and a sensor lens 21 that converges the light that has passed through the beam splitter 19 And a photodiode 22 for receiving the light collected by the sensor lens 21. .

  The laser light emitted from the first laser diode 14 is divided into three beams by the first diffraction grating 16, then passes through the dichroic prism 18, is reflected by the beam splitter 19, and is further reflected by the rising mirror 20. The light is reflected and irradiated to the recording surface of the optical disk through the objective lens. The laser light reflected by the recording surface of the optical disc enters the beam splitter 19 through the objective lens and the rising mirror 20, passes through the beam splitter 19, and further enters the photodiode 22 through the sensor lens 21. The laser light emitted from the second laser diode 15 is divided into three beams by the second diffraction grating 17 and then reflected by the dichroic prism 18, but the subsequent optical path is emitted from the first laser diode 14. This is the same as the case of the laser beam. Thus, the laser light is transmitted or reflected through the dichroic prism 18 and the beam splitter 19. At this time, these optical components generate heat as described above.

  FIG. 2 is a schematic perspective view showing a state in which a metal cover is attached to the housing 11 of FIG.

  As shown in FIG. 2, the housing 11 is covered with a metal cover 23 for protecting optical components. However, with such a configuration, the heat generated by the optical component tends to be trapped in the optical component housing portion 11A. For this reason, in the optical pickup 100 of the present embodiment, measures for heat dissipation of optical components are taken.

  FIG. 3 is a schematic cross-sectional view showing an example of the heat dissipation structure of the optical component in the optical pickup 100.

  As shown in FIG. 3, the optical component 30 such as a beam splitter is bonded and fixed at a predetermined position on the bottom surface of the housing 11, and the optical component 30 is covered with a metal cover 23. Further, in the present embodiment, a heat conductive resin 31 is provided between the upper surface 30 u of the optical component 30 and the metal cover 23. It is preferable that the heat conductive resin 31 has an appropriate viscosity that is easy to apply on the optical component and can maintain the applied state. Thus, when the optical component 30 and the metal cover 23 are connected by the heat conductive resin 31, even if the optical component 30 generates heat due to the heat loss of the laser light, the heat passes through the heat conductive resin 31. Therefore, the heat dissipation of the optical component 30 can be improved.

  FIG. 4 is a schematic cross-sectional view showing another example of a heat dissipation structure for an optical component.

  As shown in FIG. 4, in this heat dissipation structure, a heat conductive resin 31 is provided on the upper surface 30 u and the side surface 30 s of the optical component 30. Needless to say, the side surface 30s at this time is a surface different from the laser light incident surface and the reflecting surface. Thus, by providing the heat conductive resin 31 not only on the upper surface 30u of the optical component but also on the side surface 30s, the heat dissipation of the optical component 30 can be further enhanced.

  FIG. 5 is a block diagram schematically showing an example of the configuration of an optical recording / reproducing apparatus using the optical pickup 100 described above.

  As shown in FIG. 5, the optical recording / reproducing apparatus 200 includes a spindle motor 102 for rotating the optical disc 101, an optical pickup 100 for irradiating the optical disc 101 with laser light and receiving reflected light, a spindle motor 102, A controller 103 that controls the operation of the optical pickup 100, a laser drive circuit 104 that supplies a laser drive signal to the optical pickup 100, and a lens drive circuit 105 that supplies a lens drive signal to the optical pickup 100 are provided.

  The controller 103 includes a focus servo tracking circuit 106, a tracking servo tracking circuit 107, and a laser control circuit 108. When the focus servo tracking circuit 106 is activated, the information recording surface of the rotating optical disc 101 is focused. When the tracking servo tracking circuit 107 is activated, the eccentricity signal track of the optical disc 101 is The laser beam spot is in an automatic tracking state. The focus servo tracking circuit 106 and the tracking servo tracking circuit 107 are each provided with an auto gain control function for automatically adjusting the focus gain and an auto gain control function for automatically adjusting the tracking gain. The laser control circuit 108 is a circuit that generates a laser drive signal supplied from the laser drive circuit 104, and generates an appropriate laser drive signal based on the recording condition setting information recorded on the optical disc 101. .

  The focus servo tracking circuit 106, the tracking servo tracking circuit 107, and the laser control circuit 108 do not need to be circuits incorporated in the controller 103, and may be separate components from the controller 103. Furthermore, these need not be physical circuits, and may be software executed in the controller 103.

  As described above, according to the optical pickup of the present embodiment, the metal cover is provided above the optical component, and the optical component and the metal cover are connected with the heat conductive material. It is possible to dissipate heat generated from the optical component when the laser light is transmitted.

  Further, according to the optical recording / reproducing apparatus of the present embodiment, since the above-described optical pickup is used as one of the mounted components, an inexpensive and high-performance optical recording / reproducing apparatus can be realized.

  As mentioned above, although this invention was demonstrated based on the preferable embodiment, this invention is not limited to the above embodiment, It is possible to add a various change within the range which does not deviate from the meaning of this invention, Needless to say, they are also included in the scope of the present invention.

  For example, in the above embodiment, the heat dissipation of the optical component is enhanced by connecting the optical component and the metal cover via a heat conductive material, but the present invention is not limited to such a configuration, for example, In addition, a dedicated heat sink may be attached to the upper surface of the optical component, or the heat sink and the optical component may be connected via a heat conductive material. In addition, as described above, the mounting position of the heat dissipation member is not limited to the upper surface of the optical component, and may be provided at a position facing at least one surface of the optical component.

  In the above-described embodiment, the dichroic prism and the deflecting beam splitter are targeted. However, the optical component that is a target for heat dissipation is not limited to these, and various other types that easily generate heat, such as a half mirror. Optical components can be targeted. However, the optical component mentioned here is a passive optical component that transmits or reflects laser light, and is not an active optical component such as a laser diode.

FIG. 1 is a schematic perspective view showing a configuration of an optical pickup 100 according to a preferred embodiment of the present invention. FIG. 2 is a schematic perspective view showing a state in which a metal cover is attached to the housing 11. FIG. 3 is a schematic cross-sectional view showing an example of the heat dissipation structure of the optical component in the optical pickup 100. FIG. 4 is a schematic cross-sectional view showing another example of a heat dissipation structure for an optical component. FIG. 5 is a block diagram schematically showing an example of the configuration of an optical recording / reproducing apparatus 200 using the optical pickup 100 described above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Housing 11A Optical component accommodating part 12 Objective lens drive device 14 1st laser diode 15 2nd laser diode 16 1st diffraction grating 17 2nd diffraction grating 18 Dichroic prism 19 Deflection beam splitter 20 Rising mirror 21 Sensor lens 22 Photodiode 23 Metal cover 30 Optical component 30 u Optical component upper surface 30 s Optical component side surface 31 Thermal conductive resin 100 Optical pickup 101 Optical disk 102 Spindle motor 103 Controller 104 Laser drive circuit 105 Lens drive circuit 106 Focus servo tracking circuit 107 Tracking servo Tracking circuit 108 Laser control circuit 200 Optical recording / reproducing apparatus

Claims (5)

  An optical pickup comprising: an optical component; a heat radiating member facing at least one surface of the optical component; and a heat conductive material that connects the optical component and the heat radiating member.   2. The optical pickup according to claim 1, wherein the thermal conductive material is provided on a surface different from a laser light incident / exit surface and a reflective surface among a plurality of surfaces of the optical component.   The optical pickup according to claim 1, further comprising: a housing that houses the optical component; and a metal cover attached to an opening of the housing, wherein the heat dissipation member is the metal cover.   The optical pickup according to any one of claims 1 to 3, wherein the optical component is a dichroic prism, a beam splitter, or a half mirror.   An optical recording / reproducing apparatus comprising the optical pickup according to claim 1.

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