JP2009295240A - Optical pickup device and lens unit - Google Patents

Abstract

Even when the arrangement position of a heat source is unknown, it is possible to suppress deterioration of lens characteristics due to a distribution of heat deviation formed on the lens.
An optical pickup device includes a light source, an objective lens that condenses light emitted from the light source on an optical disc, a drive mechanism that displaces the objective lens 50 by energizing a coil, and heat to the objective lens 50. Connected to the heat conductor 70. The heat conductor 70 heats the objective lens 50 as a whole with heat directly or indirectly transmitted from the coil, or receives local heat generated in the objective lens 50 in accordance with the location of the coil.
[Selection] Figure 5

Description

  The present invention relates to an optical pickup device and a lens unit.

  2. Description of the Related Art Conventionally, an optical pickup device that reads / writes information from / to an optical disc has been used in various electronic devices. Recently, the data capacity of data to be written on an optical disk has increased, and accordingly, the capacity of the optical disk has been increased. An optical pickup device having a new configuration has also been developed in response to a large-capacity optical disk.

  In general, various heat sources are arranged in the optical pickup device. For example, as a heat source included in the optical pickup device, an actuator that displaces an objective lens using a magnetic circuit is known.

  When the coil in the magnetic circuit is energized to displace the objective lens, the coil generates heat. When the heat generated in the coil is transmitted to the objective lens, the lens characteristics of the objective lens may deteriorate, and it may be impossible to stably read / write information from / to the optical disc. This is because when the lens characteristics of the objective lens deteriorate due to global or local heating, the shape of the light spot formed on the optical disk deteriorates, or the wavefront aberration of the light projected onto the optical disk by the objective lens This is because it may occur. In the case where the objective lens is formed of a resin material, the deterioration of lens characteristics accompanying a temperature change becomes a significant problem.

  Patent Document 1 discloses a technique for keeping a focused spot favorable even if the objective lens is in a heat-biased state. Specifically, the objective lens is molded from resins having different characteristics. Similarly, Patent Documents 2 and 3 disclose techniques for changing the lens structure of the objective lens.

Patent Document 4 discloses a technique for displacing the objective lens in the optical axis direction in order to reduce a change in lens characteristics of the objective lens due to heat from a heat source. Patent Document 5 discloses a technique for providing a temperature adjusting means for preventing a positional shift and a posture shift of an optical component.
JP 2007-188553 A JP 2003-131125 A JP 2006-2444577 A JP 2007-328886 A JP 2007-317339 A

  Incidentally, the location of the heat source included in the optical pickup device depends on the design of the optical pickup device. In other words, the location of the heat source in the optical pickup device varies depending on the product type of the optical pickup device.

  The biased heat distribution formed on the objective lens corresponds to the location of the heat source in the optical pickup device. Even if the optical characteristic or structure of the objective lens is changed as in Patent Documents 1 to 3, the optical pickup device in which the heat source is arranged at an unexpected position suppresses the objective lens lens characteristic from being deteriorated. There are cases where it cannot be done. The uneven heat distribution indicates a state where the temperature is different for each part.

  That is, it is strongly desired to suppress the deterioration of the lens characteristics of the objective lens due to the heat distribution formed on the objective lens without depending on the configuration (product type) of the optical pickup device.

  The present invention has been made to solve such problems, and suppresses deterioration of lens characteristics due to the uneven heat distribution formed on the lens even when the position of the heat source is unknown. The purpose is to do.

  An optical pickup device according to the present invention includes a light source, an objective lens that condenses light emitted from the light source on an optical disc, and a drive mechanism that displaces the objective lens by energizing a coil. A heat conductor that is thermally connected to the coil, the heat conductor generally warms the objective lens with heat transferred directly or indirectly from the coil, or of the coil. It receives the local heat generated in the objective lens according to the arrangement location.

  By providing the heat conductor, it is possible to suppress the deterioration of the lens characteristics due to the uneven heat distribution formed on the lens even when the position of the heat source is unknown.

  The objective lens may include a lens portion and a flange portion surrounding the lens portion, and the thermal conductor may be formed to surround the lens portion.

  It is preferable that a lens barrel for holding the objective lens is further provided, and the thermal conductor has a higher thermal conductivity than the lens barrel.

  The objective lens and the lens barrel are preferably made of a resin material, and the heat conductor is preferably made of a conductive material.

  The lens barrel may have a placement surface on which the objective lens is placed, and the thermal conductor may be directly formed in a layer on the placement surface of the lens barrel.

  The heat conductor is preferably formed in a layered shape directly on the edge portion of the objective lens.

  It is preferable that the thermal conductor further includes a plate-like member formed directly in a layer shape.

  The annular heat conductor is preferably partially cut.

  A lens unit according to the present invention is a lens unit comprising: an objective lens that is displaced by a drive mechanism in an optical pickup device; and a thermal conductor that is thermally connected to the objective lens, The conductor warms the objective lens as a whole with heat directly or indirectly transmitted from a heat source, or receives local heat generated in the objective lens according to the location of the heat source.

  According to the present invention, even when the arrangement position of the heat source is unknown, it is possible to suppress the deterioration of the lens characteristics due to the uneven heat distribution formed on the lens.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Each embodiment is simplified for convenience of explanation. Since the drawings are simple, the technical scope of the present invention should not be interpreted narrowly based on the drawings. The drawings are only for explaining the technical matters, and do not reflect the exact sizes or the like of the elements shown in the drawings. The same elements are denoted by the same reference numerals, and redundant description is omitted. Words indicating directions such as up, down, left, and right are used on the assumption that the drawing is viewed from the front.

[First Embodiment]
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing the configuration of the optical pickup device. FIG. 2 is a schematic perspective view of a driving mechanism for displacing the objective lens. 3A and 3B are explanatory diagrams for explaining the operation of the drive mechanism for displacing the objective lens. FIG. 4 is a schematic perspective view of a lens barrel holding a lens. FIG. 5 is a schematic diagram showing a cross-sectional configuration of a lens barrel holding a lens. FIG. 6 is a schematic diagram for explaining the formation range of the metal film. 7 and 8 are explanatory diagrams for explaining the heat deviation formed in the lens.

  As shown in FIG. 1, the optical pickup device 200 includes a semiconductor laser element 100, a collimator lens 105, a polarization beam splitter 110, an actuator 112, an objective lens 118, a condenser lens 120, a photodetector 125, a control circuit 128, and an RF. A circuit 129 is included. It is assumed that a phase plate for controlling the polarization state of the laser light is appropriately disposed on the optical path.

  First, individual elements included in the optical pickup device 200 will be described.

  The semiconductor laser element 100 emits laser light in accordance with a drive signal input from the outside. The semiconductor laser element 100 may be a wavelength tunable semiconductor laser element, or may be a semiconductor laser element that outputs emitted light having a predetermined wavelength (for example, wavelengths of 780 nm, 650 nm, 405 nm, etc.).

  The collimator lens 105 collimates the light beam emitted from the semiconductor laser element 100. The polarization beam splitter 110 transmits S-polarized incident light and reflects P-polarized incident light. The actuator 112 energizes a coil included in the magnetic circuit to displace the objective lens 118. The objective lens 118 condenses incident light on the disk surface of the optical disk OPD and forms a light spot on the disk surface of the optical disk OPD.

  The condensing lens 120 condenses incident light on the light incident surface of the photodetector 125. The photodetector 125 detects the incident position of the incident light on the light incident surface, and outputs a signal indicating the incident position of the incident light. The photodetector 125 is a resistance division type position detection element or a quadrant photodiode.

  The control circuit 128 controls the actuator 112 based on the output of the photodetector 125. Specifically, the control circuit 128 controls the actuator 112 to move the objective lens 118 in the focusing direction (direction approaching / disengaging from the disk surface), tracking direction (radial direction of the optical disk), radial tilt direction (optical disk). ) In the tangential tilt direction (tilt in the tangential direction of the optical disk). The RF circuit 129 outputs an RF (Radio Frequency) signal corresponding to the output of the photodetector 125.

  Next, the details of the operation of the optical pickup apparatus 200 that reads / writes information from / to the optical disk OPD will be described.

  Laser light emitted from the semiconductor laser element 100 is input to the collimator lens 105. A collimated lens 105 outputs collimated laser light. Next, the collimated laser beam is input to the polarization beam splitter 110. The laser light that has passed through the polarization beam splitter 110 is condensed in a spot shape on the disk surface of the optical disk OPD by the objective lens 118. The laser light reflected by the disk surface of the optical disk OPD is input to the polarization beam splitter 110 via the objective lens 118 and is reflected by the polarization beam splitter 110. The laser light reflected by the polarization beam splitter 110 is condensed in a spot shape on the light incident surface of the photodetector 125 via the condenser lens 120. Based on the output of the photodetector 125, the control circuit 128 controls the actuator 112 to displace the objective lens 118. The RF circuit 129 outputs an RF signal according to the output of the photodetector 125.

  FIG. 2 shows a schematic perspective view of a drive mechanism for displacing the objective lens. However, from the viewpoint of clarification of explanation, illustration of wiring connection of the magnetic circuit included in the drive mechanism is omitted.

  As shown in FIG. 2, the movable portion 45 is surrounded by a plurality of magnets (permanent magnets) 15. The drive mechanism 190 displaces the movable part 45 by energizing the coil attached to the movable part 45. The drive mechanism 190 is formed by the coil and the magnet 15 attached to the movable part 45.

  The movable part 45 includes an objective lens 50, a lens barrel 51, and a base part 46. The base portion 46 has a portion in which focusing coils 3a and 3b and radial tilt coils 13a and 13b are stacked. Further, tracking coils 4 a to 4 d and tangential tilt coils 14 a to 14 d are attached to the side surface of the base portion 46. Each coil is connected to an external current source via a flexible wiring.

  The magnets 15a to 15c and the magnets 15d to 15f are arranged to face each other with the movable portion 45 interposed therebetween. The magnet 15g and the magnet 15h are arranged to face each other with the movable portion 45 interposed therebetween. The magnet 15 is fixed to a highly permeable yoke member (not shown). By adopting such a configuration, leakage of magnetic flux can be suppressed as much as possible.

  The direction of the magnetic flux formed by the magnet 15a is opposite to the direction of the magnetic flux formed by the magnet 15d. The same applies to the magnet 15b and the magnet 15e. The same applies to the magnet 15c and the magnet 15f. On the other hand, the direction of the magnetic flux formed by the magnet 15g matches the direction of the magnetic flux formed by the magnet 15h.

  The movable portion 45 is displaced in a desired direction by the Lorentz force generated in response to energization of each coil. Here, the movable part 45 includes a focusing direction (direction approaching / distant from the disk surface), tracking direction (radial direction of the optical disk), radial tilt direction (tilt in the radial direction of the optical disk), tangential tilt direction ( (Tilt in the tangential direction of the optical disk).

  This point will be supplemented with reference to FIGS. 3A and 3B. FIG. 3A is an explanatory diagram for explaining the movement of the movable portion 45 in the radial tilt direction. FIG. 3B is an explanatory diagram for explaining the movement of the movable portion 45 in the tangential tilt direction. In addition, the coil shall be appropriately connected with a conducting wire in order to realize the operation described later. Further, it is assumed that a current having an appropriate amount of current flows through each coil at an appropriate timing by the drive circuit.

  In the case of FIG. 3A, when the radial tilt coils 13a and 13b are energized, the Lorentz force generated by the energization of the coils urges the radial tilt coil 13b in the positive z-axis direction, and the radial tilt coil 13a becomes negative in the z-axis. Biased in the direction. As a result, a moment 18 in the radial tilt direction is generated, and the movable portion 45 is tilted in the radial direction. In addition, when it is desired to tilt the movable portion 45 in the reverse direction, the direction of the current flowing through the coil is reversed.

  In the case of FIG. 3B, when the tangential tilt coils 14a to 14d are energized, the tangential tilt coils 14a and 14b are urged in the positive z-axis direction by the Lorentz force generated by energization of the coils, and the tangential tilt coil 14c. , 14d are biased in the negative direction of the z-axis. As a result, a moment 19 in the tangential tilt direction is generated, and the movable portion 45 is tilted in the tangential direction. In addition, when it is desired to tilt the movable portion 45 in the reverse direction, the direction of the current flowing through the coil is reversed.

  With reference to FIG. 4 thru | or FIG. 6, the structure of the objective lens 50 vicinity of the movable part 45 is demonstrated.

  As shown in FIGS. 4 and 5, the objective lens 50 is attached to the lens barrel 51, and the objective lens 50 is held by the lens barrel 51. In the present embodiment, a metal film (thermal conductor) 70 is formed in advance on the mounting surface 52 of the lens barrel 51. The objective lens 50 is placed on the placement surface 52 on which the metal film 70 is formed.

  The metal film 70 heats the objective lens 50 as a whole with heat transmitted from the energized coil. Therefore, the objective lens 50 is locally heated by the heat from the coil due to the heat conduction action of the metal film 70, and the formation of a partially biased heat distribution on the objective lens 50 is effectively suppressed. The This point will become clear from the following description. This will be specifically described below.

  As shown in FIG. 5, the objective lens 50 includes a lens unit 60 and an edge unit 61.

  The objective lens 50 has a lens portion 60a on its front surface and a lens portion 60b on its back surface. Both lens parts 60a and 60b are convex bodies. Incident light is condensed in a spot shape on the disk surface of the optical disk OPD through the lens surface of each lens unit. That is, each lens part 60 is an optically functioning part. The objective lens 50 is a resin lens (plastic lens) manufactured by molding a resin material with a mold.

  The edge portion 61 of the objective lens 50 is formed so as to surround the lens portion 60 of the objective lens 50. The edge portion 61 is a flat plate-like portion extending along an axis perpendicular to the optical axis AX. The edge portion 61 is not a portion that functions optically like the lens portion 60, but a portion for attaching the objective lens 50 to the lens barrel 51.

  The lens barrel 51 is a cylindrical member. The thickness W1 of the upper end portion of the lens barrel 51 is thinner than the thickness W2 of the barrel portion of the lens barrel 51. Thereby, a space for accommodating the objective lens 50 is secured at the upper end of the lens barrel 51. More specifically, a mounting surface 52 on which the objective lens 50 is mounted is formed on the upper end side of the lens barrel 51. Similar to the objective lens 50, the lens barrel 51 is also a resin component (plastic component) manufactured by molding a resin material with a mold. The mounting surface 52 can also be grasped as a facing surface that faces the objective lens 50.

  It is possible to reduce the weight of the lens barrel 51 by molding the lens barrel 51 from a resin material, compared to molding the lens barrel 51 from a metal material. By reducing the weight of the lens barrel 51, the driving amount for displacing the lens barrel 51 can be reduced. In addition, it is possible to keep the price of the lens barrel 51 lower when the lens barrel 51 is molded from a resin material than when the lens barrel 51 is molded from a metal material. By reducing the price of the lens barrel 51, the price of the optical pickup device 200 can be reduced.

  The metal film 70 is formed on the mounting surface 52 of the lens barrel 51 by a normal thin film forming technique (evaporation, sputtering, coating, etc.). The metal film 70 is made of, for example, copper (Cu), silver (Ag), a silver alloy, or gold (Au). The metal film 70 can also be grasped as a heat conductive layer.

In addition, when the plating process is performed on the lens barrel 51 in order to form the metal film 70 on the lens barrel 51, the lens barrel 51 is preferably pretreated with scCO _{2 in} a supercritical state (referred to as supercritical carbon dioxide) in advance. . That is, it is preferable to dissolve a palladium (Pb) complex in scCO ₂ and embed Pb as a nuclide near the plastic surface. This eliminates the need for a conventional etching process using hexavalent chromium or the like, and can significantly reduce the environmental load in the plating process.

  As shown in FIG. 6, the metal film 70 is formed on the back surface of the edge portion 61. The metal film 70 is formed in a ring shape and surrounds the lens portion 60b.

  The metal film 70 functions as a heat conductor that conducts heat. Since the thermal conductivity of the metal film 70 only needs to be larger than the thermal conductivity of the objective lens 50 and the thermal conductivity of the lens barrel 51, the thermal conductor may be formed of a material other than metal. The lens unit is formed including at least the objective lens 50 and the metal film 70.

  Here, with reference to FIG.7 and FIG.8, the partially biased heat distribution formed in the objective lens 50 is demonstrated. As shown in FIG. 7, it is assumed that a coil (heat source) 40 for displacing the objective lens 50 is arranged around a lens barrel 51 that holds the objective lens 50. In this case, when the coil 40 is energized, the coil 40 generates heat. If this state continues for a certain period, as schematically shown in FIG. 8, the portions R <b> 1 to R <b> 3 of the objective lens 50 are heated corresponding to the arrangement location of the coil 40. That is, in the objective lens 50, a heat distribution having a different amount of heat is formed for each portion. As described above, when the objective lens 50 is in a heat-biased state, the optical function of the objective lens 50 is deteriorated. As a result, there is a possibility that information cannot be read / written on the optical disc OPD as intended.

  In the present embodiment, as described above, the metal film 70 is formed in advance on the mounting surface 52 of the lens barrel 51, and the objective lens 50 is mounted on the mounting surface 52 on which the metal film 70 is formed. The In the process of fixing the objective lens 50 to the lens barrel 51 by bonding or fitting, the metal film 70 is bonded to the edge portion 61 of the objective lens 50, and the metal film 70 is directly attached to the edge portion 61 of the objective lens 50. Contact.

  The metal film 70 functions as a heat conductor. Since the metal film 70 has higher thermal conductivity than the objective lens 50 and the lens barrel 51, the thermal diffusion rate in the metal film 70 is sufficiently faster than the thermal diffusion rate from the metal film 70 to the objective lens 50. Accordingly, the heat received by the metal film 70 from the coil is first diffused to the entire metal film 70, and is diffused from the metal film 70 to the objective lens 50 with a time delay. When heat diffuses from the metal film 70 to the objective lens 50, the metal film 70 is already in a heated state. The heat from the coil is first received by the metal film 70, diffused throughout the metal film 70, and diffused to the objective lens 50 through the metal film 70 that has been entirely heated.

  By providing the metal film 70 having such a high thermal conductivity on the mounting surface 52 of the lens barrel 51, the objective lens 50 is locally heated by the heat from the coil and partially biased toward the objective lens 50. The formation of a heat distribution is effectively suppressed. Therefore, even when the arrangement position of the heat source is unknown, it is possible to suppress the deterioration of the lens characteristics of the lens due to the uneven heat distribution formed on the lens.

  Even if the objective lens 50 is heated as a whole, the influence of the temperature change of the objective lens 50 is achieved by displacing the objective lens 50 to a desired position on the optical axis by feedback control by the optical pickup device 200. Can be avoided.

  On the other hand, when the objective lens 50 is locally heated and the objective lens 50 is in a heat-biased state, the objective lens 50 is displaced to a desired position on the optical axis by feedback control by the optical pickup device 200. However, the influence of the thermal deviation state of the objective lens 50 cannot be avoided.

[Second Embodiment]
A second embodiment of the present invention will be described with reference to FIGS. FIG. 9 is a schematic perspective view of the objective lens 50 according to the second embodiment. FIG. 10 is a schematic diagram illustrating a cross-sectional configuration of the objective lens 50 according to the second embodiment.

  As apparent from FIGS. 9 and 10, unlike the first embodiment, in this embodiment, the metal film 70 is not formed on the lens barrel 51, but directly on the edge portion 61 of the objective lens 50. Then, a metal film 70 is formed. Even in such a case, the same effect as the first embodiment can be obtained.

  Here, as shown in FIG. 10, the metal film 70 is continuously formed on the front surface 62, the side surface 63, and the back surface 64 of the edge portion 61. Thereby, the heat capacity of the metal film 70 can be made sufficient. However, the formation range of the metal film 70 may be limited to any one of the front surface 62, the side surface 63, and the back surface 64 of the edge portion 61.

  The objective lens 50 is assumed to be attached to the same lens barrel 51 as that in the first embodiment (however, the metal film 70 is not formed). Further, when the metal film 70 is directly formed on the edge portion 61 of the objective lens 50, it is necessary to mask so that the metal film 70 is not formed on the lens portion 60 of the objective lens 50.

[Third Embodiment]
A third embodiment of the present invention will be described with reference to FIGS. FIG. 11 is a schematic explanatory view showing attachment of the ring-shaped body 80 to the objective lens 50. FIG. 12 is a schematic diagram showing a state in which the objective lens 50 and the ring-shaped body 80 are attached to the lens barrel 51.

  As shown in FIG. 11, a ring-shaped body 80 is attached to the objective lens 50. As shown in FIG. 12, the annular body 80 is formed by laminating an annular metal film 70 on an annular substrate 81. The ring-shaped body 80 is manufactured by forming the metal film 70 on the substrate 81.

  The substrate 81 is a plate-like member having an opening in a range corresponding to the lens unit 60 of the objective lens 50. The substrate 81 is a resin component (plastic component) manufactured by molding a resin material with a mold. The metal film 70 is formed in a ring shape according to the shape of the substrate 81.

  As is apparent from FIGS. 11 and 12, in this embodiment, unlike the above-described embodiment, the ring-shaped body 80 in which the metal film 70 is formed on the substrate 81 is directly placed on the edge portion 61 of the objective lens 50. To do. Similar to the first embodiment, the metal film 70 is thermally connected to the objective lens 50 and has a higher thermal conductivity than the objective lens 50. The local heat generated in an arbitrary part of the objective lens according to the arrangement position of the coil is received by the metal film 70 in a short time. Therefore, even if the objective lens 50 is locally heated by the heat generated in the coil, the local heat generated in the objective lens 50 is received by the metal film 70 so that the objective lens 50 is partially biased. It is possible to effectively suppress the formation of a heat distribution. In this case, the metal film 70 functions as a heat radiating member.

  In the present embodiment, there are cases where the manufacturing process can be simplified as compared with the above-described embodiment. This is because the process of manufacturing the objective lens 50 and the lens barrel 51 may be left as it is by adding the process of manufacturing the annular body 80 mainly. Note that when the thickness of the metal film 70 is sufficient, the substrate 81 is not necessary.

[Fourth Embodiment]
A fourth embodiment of the present invention will be described with reference to FIGS. FIG. 13 is a schematic perspective view of an objective lens 50 according to the fourth embodiment. FIG. 14 is a schematic view of the objective lens 50 as viewed from the back.

  As is apparent from FIGS. 13 and 14, in the present embodiment, unlike the second embodiment, the metal film 70 formed on the edge portion 61 of the objective lens 50 is partially removed. That is, the ring-shaped metal film 70 is partially cut, and the edge portion 61 of the objective lens 50 is partially exposed. By adopting such a configuration, it is possible to suppress a desired operation of the actuator 112 from being hindered with the additional arrangement of the metal film 70. In this embodiment, the same effect as that of the second embodiment can be obtained.

  When the metal film 70 is formed in a ring shape, current may flow through the metal film 70 due to the influence of the surrounding magnetic field. In such a case, the surrounding magnetic field may be disturbed by the current flowing through the metal film 70. In the present embodiment, in view of this point, the annular metal film 70 is partially removed, and the edge portion 61 is partially exposed. Thereby, the reflux of current in the metal film 70 can be effectively suppressed. As a result, it is suppressed that the operation of the actuator 112 is hindered with the additional arrangement of the metal film 70.

  The technical scope of the present invention is not limited to the above-described embodiment. The heat source should not be limited to coils. The range in which the metal film 70 is formed is arbitrary. The metal film 70 may be formed on the entire peripheral surface of the lens barrel 51. If it is outside the effective diameter range, the metal film 70 may be partially formed on the lens portion 60 of the objective lens 50. The heat conductor may be formed of a material other than metal.

  Further, the above-described embodiments can be combined with each other, and it is not allowed to understand each embodiment as being completely independent. For example, the fourth embodiment can be applied to the first embodiment or the third embodiment.

1 is a block diagram illustrating a configuration of an optical pickup device according to a first embodiment of the present invention. It is a schematic perspective view of the drive mechanism which displaces the objective lens which concerns on the 1st Embodiment of this invention. It is explanatory drawing for demonstrating operation | movement of the drive mechanism which displaces the objective lens which concerns on the 1st Embodiment of this invention. It is explanatory drawing for demonstrating operation | movement of the drive mechanism which displaces the objective lens which concerns on the 1st Embodiment of this invention. 1 is a schematic perspective view of a lens barrel holding a lens according to a first embodiment of the present invention. It is a schematic diagram showing a cross-sectional configuration of a lens barrel holding a lens according to the first embodiment of the present invention. It is a schematic diagram for demonstrating the formation range of the metal film which concerns on the 1st Embodiment of this invention. It is explanatory drawing for demonstrating the thermal deviation formed in a lens. It is explanatory drawing for demonstrating the thermal deviation formed in a lens. It is a schematic perspective view of the objective lens 50 concerning the 2nd Embodiment of this invention. It is a schematic schematic diagram which shows the cross-sectional structure of the objective lens 50 concerning the 2nd Embodiment of this invention. It is a schematic explanatory drawing which shows the attachment of the annular body 80 to the objective lens 50 which concerns on the 3rd Embodiment of this invention. It is a schematic diagram which shows the state which attached the objective lens 50 and the ring-shaped body 80 to the lens-barrel 51 which concerns on the 3rd Embodiment of this invention. It is a schematic perspective view of the objective lens 50 concerning the 4th Embodiment of this invention. It is the schematic diagram which looked back at the objective lens 50 concerning the 4th Embodiment of this invention.

Explanation of symbols

200 Optical Pickup Device 15 Magnet 40 Coil 45 Movable Unit 50 Objective Lens 51 Lens Tube 52 Mounting Surface 60 Lens Unit 61 Edge 70 Metal Film

80 Ring-shaped body 81 Substrate

Claims (16)

A light source;
An objective lens for condensing the light emitted from the light source onto an optical disc;
A drive mechanism for displacing the objective lens by energizing the coil;
An optical pickup device comprising:
A thermal conductor thermally connected to the objective lens;
The said heat conductor heats the said objective lens entirely with the heat | fever directly or indirectly transmitted from the said coil, or receives the local heat which arises in the said objective lens according to the arrangement | positioning location of the said coil , Optical pickup device. The objective lens has a lens part and an edge part surrounding the lens part,
The optical pickup device according to claim 1, wherein the thermal conductor is formed so as to surround the lens unit. A lens barrel for holding the objective lens;
The optical pickup device according to claim 2, wherein the thermal conductor has a higher thermal conductivity than the lens barrel.   The optical pickup device according to claim 3, wherein the objective lens and the lens barrel are made of a resin material, and the thermal conductor is made of a conductive material. The lens barrel has a placement surface on which the objective lens is placed,
5. The optical pickup device according to claim 3, wherein the thermal conductor is directly formed in a layer shape on the mounting surface of the lens barrel.   5. The optical pickup device according to claim 3, wherein the thermal conductor is directly formed in a layer on the edge portion of the objective lens.   The optical pickup device according to claim 3 or 4, further comprising a plate-like member in which the heat conductor is directly formed in a layer shape.   The optical pickup device according to any one of claims 2 to 7, wherein the annular heat conductor is partially cut. An objective lens displaced by a drive mechanism in the optical pickup device;
A thermal conductor thermally connected to the objective lens;
A lens unit comprising:
The heat conductor heats the objective lens as a whole with heat transmitted directly or indirectly from a heat source, or receives local heat generated in the objective lens according to the location of the heat source. Lens unit. The objective lens has a lens part and an edge part surrounding the lens part,
The lens unit according to claim 9, wherein the thermal conductor is formed so as to surround the lens unit. A lens barrel for holding the objective lens;
The lens unit according to claim 10, wherein the thermal conductor has a higher thermal conductivity than the lens barrel.   The lens unit according to claim 11, wherein the objective lens and the lens barrel are made of a resin material, and the thermal conductor is made of a conductive material. The lens barrel has a placement surface on which the objective lens is placed,
The lens unit according to claim 11, wherein the heat conductor is directly formed in a layer shape on the mounting surface of the lens barrel.   The lens unit according to claim 11 or 12, wherein the thermal conductor is directly formed in a layer shape on the edge portion of the objective lens.   The lens unit according to claim 11 or 12, further comprising a plate-like member in which the heat conductor is directly formed in a layer shape.   The lens unit according to any one of claims 10 to 15, wherein the annular heat conductor is partially cut.

Images