JP2006164416A - Optical pickup device and optical disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical pickup device and an optical disk device which suppress occurrence of aberration caused by deformation of an objective lens when temperature distribution of a lens holder is not uniform, and which also permit to attain miniaturization. <P>SOLUTION: The optical pickup device comprises a light source, a condenser member for condensing the light from the light source, and a holder mounted with the condenser member and two or more coils, and the holder is characterized by having two or more fixing parts for fixing the condenser member and having each of a pair of focus coils 33, 34 among the coils on both sides of the holder. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical disc apparatus that can be mounted on a portable electronic device such as a notebook personal computer or an electronic device such as a stationary personal computer, and an optical pickup device mounted on the optical disc device.

  In recent years, optical disc devices are not only used for recording and reproducing on CDs and DVDs with infrared lasers and red lasers, but also with short wavelength lasers such as blue lasers. There has been a demand for performing at least one of the reproductions.

There exists (patent document 1) as a prior example.
JP-A-9-91725

  An optical pickup in which the contact area between the lens holder and the objective lens is reduced to prevent thermal deformation of the objective lens is described in (Patent Document 1).

  However, (Patent Document 1) does not describe a configuration in which the temperature distribution of the lens holder is biased and the size is reduced as much as possible.

  The present invention solves the above-described problems, and provides an optical pickup device and an optical disc device that can suppress the occurrence of aberration due to deformation of the objective lens and can be downsized when the temperature distribution of the lens holder is biased. The purpose is that.

  The present invention has a light source, a condensing member that condenses light from the light source, and a holder to which the condensing member and a plurality of coils are attached, and the holder includes a plurality of fixing portions that fix the condensing member. Each of the pair of focus coils on both sides of the holder.

  The present invention can suppress the occurrence of aberration due to deformation of the objective lens when the temperature distribution of the lens holder is biased, and can achieve downsizing of the apparatus.

  FIG. 1 is a schematic diagram showing an optical pickup device according to an embodiment of the present invention.

  In FIG. 1, reference numeral 1 denotes a short-wavelength optical unit that emits a short-wavelength laser. Light emitted from the short-wavelength optical unit 1 has a wavelength of 400 nm to 415 nm. In this embodiment, light of about 405 nm is emitted. It was configured as follows. In general, light having the above-described laser wavelength is blue to purple. In the present embodiment, the details of the short-wavelength optical unit 1 will be described later, but a light source unit 1a that emits a short-wavelength laser, a light-receiving unit 1b for signal detection that receives light reflected from the optical disc 2, It includes a light receiving portion 1c provided to monitor the amount of light emitted from the light source portion 1a, an optical member 1d, and a holding member (not shown) that holds these constituent members in a predetermined positional relationship. Yes. The light source unit 1a is provided with a semiconductor laser element (not shown) mainly composed of GaN or GaN, and light emitted from the semiconductor laser element is incident on the optical member 1d, and the incident light Part of the light is reflected by the optical member 1d and enters the light receiving portion 1c. Although not shown, a circuit for converting light into an electric signal by the light receiving unit 1c and adjusting the intensity of light emitted from the light source unit 1a to a desired intensity based on the electric signal is provided. . Further, most of the light emitted from the light source unit 1a is guided toward the optical disc 2 through the optical member 1d. The light reflected by the optical disk 2 is incident on the light receiving unit 1b through the optical member 1d. The light receiving unit 1b converts light into an electrical signal, and generates an RF signal, a tracking error signal, a focus error signal, and the like from the electrical signal. In the optical member 1d, a hologram 1e for separating the reflected light from the optical disc 2 is provided so that a focus error signal can be obtained.

  In this embodiment, in order to reduce the size of the optical pickup device, the optical pickup device is configured as one short wavelength optical unit including the light source unit 1a, the light receiving units 1b and 1c, and the optical member 1d. At least one of 1c may be configured to be separated from the short wavelength optical unit 1 or configured as a separate unit, or the optical member 1d may be configured to be separated from the short wavelength optical unit 1 and configured as a separate unit.

  Reference numeral 3 denotes a long wavelength optical unit that emits a long wavelength laser. The light emitted from the long wavelength optical unit 3 has a wavelength of 640 nm to 800 nm, and emits a single type of light or a plurality of types of light. A plurality of light beams having wavelengths are emitted. In the present embodiment, a light beam having a wavelength of about 660 nm (red: for example for DVD) and a light beam of about 780 nm (for infrared: for example, for CD) are emitted. In the present embodiment, details of the long wavelength optical unit 3 will be described later, but a light source unit 3a that emits a long wavelength laser, a light detection unit 3b for signal detection that receives light reflected from the optical disk 2, It includes a light receiving portion 3c provided to monitor the amount of light emitted from the light source portion 3a, an optical member 3d, and a holding member (not shown) that holds these constituent members in a predetermined positional relationship. Yes. The light source unit 3a is provided with a semiconductor laser element (not shown). This semiconductor laser element is composed of a monoblock (monolithic structure), and a light flux (red) having a wavelength of about 660 nm from the monoblock element. And a light beam (infrared) of about 780 nm is emitted. In this embodiment, the monoblock element emits two light beams. However, a single block element may emit two light beams. A plurality of light beams emitted from the semiconductor laser element are incident on the optical member 3d, and a part of the incident light is reflected by the optical member 3d and enters the light receiving unit 3c. Although not shown, a circuit for converting light into an electric signal by the light receiving unit 3c and adjusting the intensity of light emitted from the light source unit 3a to a desired intensity based on the electric signal is provided. . Further, most of the light emitted from the light source unit 3a is guided toward the optical disc 2 through the optical member 3d. The light reflected by the optical disk 2 is incident on the light receiving unit 3b through the optical member 3d. The light receiving unit 3b converts light into an electrical signal, and generates an RF signal, a tracking error signal, a focus error signal, and the like from the electrical signal. The optical member 3d is provided with a hologram 3e that separates the reflected light from the optical disc 2 into a plurality of pieces and guides them to a predetermined location on the light receiving unit 3b in order to generate a focus error signal for CD. .

  In this embodiment, in order to reduce the size of the optical pickup device, the optical pickup device is configured as one long wavelength optical unit 3 including the light source unit 3a, the light receiving units 3b and 3c, and the optical member 3d. , 3c may be configured to be separated from the long wavelength optical unit 3 or may be configured as a separate unit. Alternatively, the optical member 3d may be configured to be separated from the long wavelength optical unit 3 and configured as a separate unit.

  Reference numeral 4 denotes a beam shaping lens through which light emitted from the short wavelength optical unit 1 and reflected light from the optical disk 2 pass. The beam shaping lens 4 is preferably made of glass with little deterioration due to the passage of a short wavelength laser. In the present embodiment, the beam shaping lens 4 is made of glass. However, the beam shaping lens 4 can be made of other materials as long as the material is less deteriorated by the passage of the short wavelength laser. is there. The beam shaping lens 4 is provided for the purpose of canceling the astigmatism of the short wavelength laser and the astigmatism generated in the optical path from the short wavelength optical unit 1 to the optical disc 2. For the purpose of the beam shaping lens 4, the light reflected from the optical disk 2 may be incident on the short wavelength optical unit 1 without going through the beam shaping lens 4, but the reflected light from the optical disk 2 is optically arranged. In this embodiment, the light is incident on the short wavelength optical unit 1 through the beam shaping lens 4. In the present embodiment, the beam shaping lens 4 is used so as to reduce the astigmatism of short wavelength light. However, a beam shaping prism or a beam shaping hologram may be used instead.

  Further, convex portions 4a and concave portions 4b are respectively provided at both ends of the beam shaping lens 4, and the light emitted from the short wavelength optical unit 1 is first incident on the convex portions 4a and emitted from the concave portions 4b. The shaping lens 4 is arranged.

  Reference numeral 5 denotes an optical component, and the optical component 5 is arranged at the tip of the beam shaping lens 4 on the optical path and arranged on the concave portion 4b side of the beam shaping lens 4. That is, the light emitted from the short wavelength optical unit 1 enters the optical component 5 through the beam shaping lens 4, is guided to the optical disc 2, and the light reflected from the optical disc 2 is the optical component 5 and the beam shaping lens. Then, the light enters the short wavelength optical unit 1 through 4. The optical component 5 is provided with a hologram and has at least the following functions. That is, it is a function of separating the light reflected from the optical disc 2 into a predetermined light flux so as to mainly generate a tracking error signal. As described above, the hologram 1e provided in the optical member 1d is separated into a plurality of light beams to generate a focus error signal, and the optical component 5 generates a tracking error signal into a plurality of light beams. To separate.

  As will be described in detail later, the optical component 5 may have a function of functioning as a RIM intensity correction filter that attenuates the amount of light at a substantially central portion of short-wavelength light. Further, the optical component 5 is separated into two parts, and one optical component 5 has a function of separating the light reflected from the optical disc 2 into a predetermined light beam so as to mainly generate a tracking error signal. The optical component 5 can also have a function of a RIM intensity correction filter.

  Reference numeral 6 denotes a relay lens through which long-wavelength light emitted from the long-wavelength optical unit 3 passes. The relay lens 6 is made of a transparent member such as resin or glass. The relay lens 6 is provided to efficiently guide the light emitted from the long wavelength optical unit 3 to the rear member. Further, by providing the relay lens 6, the long wavelength optical unit 3 can be arranged on the beam splitter 7 side, so that the apparatus can be reduced in size.

  Reference numeral 7 denotes a beam splitter, and at least two transparent members 7b and 7c are joined in the beam splitter 7, and one inclined surface 7a is provided between the transparent members 7b and 7c. A wavelength selection film is provided on the inclined surface 7a. A wavelength selective film is directly formed on the inclined surface 7a of the transparent member 7c into which the light emitted from the short wavelength optical unit 1 enters, and resin or glass is formed on the inclined surface 7a of the transparent member 7c on which the wavelength selective film is formed. The transparent member 7b is joined via a joining material such as.

  The beam splitter 7 has a function of reflecting the short wavelength light emitted from the short wavelength optical unit 1 and transmitting the light emitted from the long wavelength optical unit 3. That is, the light emitted from the short wavelength unit 1 and the light emitted from the long wavelength optical unit 3 are guided in substantially the same direction.

  A collimator lens 8 is movably held. The collimator lens 8 is attached to a slider 8b, and the slider 8b is movably attached to a pair of support members 8a provided substantially in parallel. A lead screw 8c provided with a helical groove is provided so as to be substantially parallel to the support member 8a, and a protrusion entering the groove of the lead screw 8c is provided at the end of the slider 8b. A gear group 8d is coupled to the lead screw 8c, and a drive member 8e is provided in the gear group 8d. The driving force of the driving member 8e is transmitted to the lead screw 8c through the gear group 8d, and the lead screw 8c is rotated by the driving force, and as a result, the slider 8b moves along the supporting member 8a. That is, the collimator lens 8 can be moved in the direction approaching the beam splitter 7 or moved away from the beam splitter 7 depending on the difference in the driving direction and the driving speed of the driving member 8e, and the speed of the movement. Etc. can be adjusted.

  Various motors and the like are preferably used as the drive member 8e, and it is particularly preferable to use a stepping motor as the drive member 8e. That is, by adjusting the number of pulses sent to the stepping motor, the rotation amount of the lead screw 8c is determined, and as a result, the movement amount of the collimator lens 8 can be easily set.

  In this manner, by adopting a configuration in which the collimator lens 8 is brought close to or away from the beam splitter 7, the spherical aberration can be easily adjusted. That is, since the spherical aberration of the short wavelength light can be adjusted by the position of the collimator lens 8, the first recording layer provided in the short wavelength optical disc and the depth different from the first recording layer. Each of the second recording layers provided in the recording medium can be configured to effectively perform at least one of recording and reproduction.

  The collimator lens 8 is made of glass or, preferably, a short-wavelength light resin (a resin that does not deteriorate or hardly deteriorate due to a short wavelength), since long-wavelength and short-wavelength light incident from the beam splitter 7 is transmitted. . The collimator lens 8 also transmits short-wavelength or long-wavelength light reflected by the optical disk 2.

  Further, in the present embodiment, the configuration for correcting the spherical aberration of light having a short wavelength is configured such that the collimator lens 8 is moved by the driving member 8e. However, the collimator lens 8 is moved by other configurations. Alternatively, the spherical aberration of the short wavelength light may be adjusted using other means.

  Reference numeral 9 denotes a raising mirror, and the raising mirror 9 is provided with a quarter-wave member 9a that acts on short-wavelength light. As the quarter-wave member 9a, a quarter-wave plate that rotates the polarization direction of light that has passed twice (in the forward path and the return path) by approximately 90 degrees is preferably used. In the present embodiment, the quarter wavelength member 9 a is sandwiched between the rising mirrors 9. A wavelength selection film 9b is provided on the surface of the rising mirror 9 on which the light emitted from the units 1 and 3 is incident. The wavelength selection film 9b is provided so that the long wavelength light emitted from the long wavelength optical unit 3 is almost reflected. It has a function of transmitting almost all the light having a short wavelength emitted from the wavelength optical unit 1.

  Reference numeral 10 denotes an objective lens for a long wavelength laser. The objective lens 10 condenses the light reflected from the rising mirror 9 on the optical disk 2. Although the objective lens 10 is used in the present embodiment, the objective lens 10 may be composed of other condensing members such as a hologram. As a matter of course, the light reflected from the optical disk 2 passes through the objective lens 10. The objective lens 10 is made of a material such as glass or resin.

  Reference numeral 11 denotes an optical component provided between the objective lens 10 and the raising mirror 9. The optical component 11 is compatible with the optical disc 2 of DVD (light having a wavelength of approximately 660 nm) and CD (light having a wavelength of approximately 780 nm). In addition, an aperture filter for realizing a necessary numerical aperture, a polarization hologram that reacts to light having a wavelength of about 660 nm, and a quarter wavelength member (preferably a quarter wavelength plate) are provided. . The optical component 11 includes a dielectric multilayer film, a diffraction grating aperture means, and the like. A polarization hologram applies polarization to light of approximately 660 nm (separates light having a wavelength of approximately 660 nm into light for tracking error signals and focus error signals). Further, the quarter wavelength member rotates the polarization direction of the return path with respect to the forward path of light having a wavelength of approximately 660 nm and approximately 780 nm by approximately 90 degrees.

  Reference numeral 12 denotes a rising mirror that almost reflects short-wavelength light. The rising mirror 12 is provided with a reflective film.

  Reference numeral 13 denotes an objective lens, and the objective lens 13 condenses the light reflected from the rising mirror 12 on the optical disk 2. Although the objective lens 13 is used in the present embodiment, the objective lens 13 may be composed of other condensing members such as a hologram. As a matter of course, the light reflected from the optical disk 2 passes through the objective lens 13. The objective lens 13 is made of glass or resin, but when the objective lens 13 is made of resin, it is preferably made of a short-wavelength light resin (a resin that does not deteriorate or hardly deteriorate due to a short wavelength). Composed.

  Reference numeral 14 denotes an achromatic diffraction lens provided between the objective lens 13 and the raising mirror 12, and the achromatic diffraction lens 14 has a function of correcting chromatic aberration. The achromatic diffractive lens 14 is provided so as to cancel and reduce chromatic aberration caused by each optical component through which light having a short wavelength passes. The achromatic diffractive lens 14 is basically formed by forming a desired hologram on the lens, and the degree of correction of chromatic aberration can be determined by adjusting at least one of the grating pitch of the hologram and the radius of curvature of the lens. It is. The achromatic diffractive lens 14 is made of resin such as plastic or glass. In the case of using a resin or the like, the resin is preferably composed of a short-wavelength light resin (a resin that does not deteriorate or hardly deteriorate due to a short wavelength).

  The specific arrangement of the optical system configured as described above will be described below with reference to FIG.

  FIG. 2 actually shows an example in which the optical configuration shown in FIG. 1 is embodied. The shape and the like of the members shown in FIG. 1 are slightly different, but the functions are almost the same.

  Reference numeral 15 denotes a base, to which the above-described members are attached so as to be fixed or movable. The base 15 is made of a metal or metal alloy material such as zinc, zinc alloy, aluminum, aluminum alloy, titanium, or titanium alloy, and is preferably made using a die casting method or the like from the viewpoint of mass production. The base 15 is movably held by an optical pickup module as shown in FIGS.

  3 and 4, reference numeral 20 denotes a frame, to which shafts 21 and 22 arranged substantially in parallel are attached to the frame 20, and a base 15 is movably attached to the shafts 21 and 22. Further, on the opposite side of the shaft 22 from the shaft 21 side, a screw shaft 23 provided with a helical groove is attached to the frame 20 so as to be rotatable in parallel with the shafts 21 and 22. Although not shown in detail, a member provided integrally or separately on the base 15 is engaged with a groove provided on the screw shaft 23. The screw shaft 23 meshes with a gear group 24 a that is rotatably provided on the frame 20, and the gear group 24 a meshes with the feed motor 24. Accordingly, when the feed motor 24 is rotated, the gear group 24a is rotated, and the screw shaft 23 is rotated accordingly. As the screw shaft 23 is rotated, the base 15 reciprocates in the arrow direction shown in FIG. be able to. At this time, in the present embodiment, the feed motor 24 is disposed substantially parallel to the screw shaft 23. Further, the optical disk 2 is mounted on the frame 20, and a spindle motor 25 for rotating the optical disk 2 is attached by a method such as screwing or bonding.

  Further, as shown in FIG. 3, a control board 26 is provided separately from the frame 20, and the control board 26 and the base 15 are electrically joined, for example, via a flexible board 29. Further, the control board 26 is also electrically connected to the spindle motor 25 by a member not shown. The control board 26 is provided with a connector 27 for electrical connection with a control board provided in the optical disk apparatus. A flexible board or the like (not shown) is inserted into the connector 27 for electrical connection.

  Further, as shown in FIG. 4, a frame cover 30 for the purpose of protecting the member may be provided at least on the side facing the optical disk in the frame 20. A through hole 31 is provided in the frame cover 30, and at least the objective lenses 10 and 13 on the base 15 are exposed from the through hole 31, and a spindle motor 25 protrudes a predetermined amount. 3 and 4, the frame 20 is provided with an attachment portion 20a for fixing to other members, and screws or the like are inserted into the attachment portion 20a to attach the frame 20 to other members.

  In FIG. 2, a base 15 includes a short wavelength optical unit 1, a long wavelength optical unit 3, a beam shaping lens 4, an optical component 5, a relay lens 6, a beam splitter 7, a support member 8a, a lead screw 8c, and a gear group 8d. , The drive member 8e, the raising mirrors 9 and 12, etc. are bonded using an organic adhesive such as a photo-curing adhesive or an epoxy adhesive, or a metal adhesive such as solder or lead-free solder is used. Or are attached using a method such as screwing, fitting, or press-fitting.

  The lead screw 8c and the gear group 8d are rotatably attached to the base 15.

  Reference numeral 17 denotes a suspension holder. The suspension holder 17 is attached to the base 15 by various joining methods via a yoke member to be described later, and the lens holder 16 and the suspension holder 17 are coupled via a plurality of suspensions 18. The lens holder 16 is supported so as to be movable within a predetermined range with respect to the base 15. The lens holder 16 is provided with the objective lenses 10 and 13 and the optical component 11, the achromatic diffraction lens 14, and the like. When the lens holder 16 is moved, the objective lens 10 and 13 and the optical component 11 and the color are moved together with the lens holder 16. The eraser diffractive lens 14 also moves. As shown in FIG. 5, the raising mirrors 9 and 12 are attached to raised portions 15d and 15e provided on the base 15 by a photo-curing resin or an instantaneous adhesive, respectively. When the rising mirror 9 is attached to the raised portion 15d, the bonding position between the raised mirror 9 and the raised portion 15d is considered so as not to block the light transmitted through the rising mirror 9. Since the raising mirrors 9 and 12 are provided so as to be positioned below the lens holder 16, they are not shown in FIG.

  The configuration around the lens holder 16 will be described with reference to FIGS. FIG. 7 is a view showing a cross section taken along the line AA of FIG.

  As shown in FIG. 7, the lens holder 16 is provided with through holes 16a and 16b. The objective lenses 10 and 13 are dropped into the through holes 16a and 16b from the P1 direction shown in FIG. Fixed with adhesive. At this time, the outer peripheral portions of the objective lenses 10 and 13 come into contact with the peripheral portions of the through holes 16 a and 16 b of the lens holder 16. Further, the optical component 11 and the achromatic diffractive lens 14 are respectively inserted into the through holes 16a and 16b from the direction of the arrow P2 in FIG. 7, and are also fixed by a photo-curing adhesive or an instantaneous adhesive. Also at this time, the outer peripheral portions of the optical component 11 and the achromatic diffraction lens 14 come into contact with the peripheral portions of the through holes 16 a and 16 b of the lens holder 16.

  As shown in FIG. 6, reference numerals 33 and 34 denote focus coils, which are respectively wound in a substantially ring shape, and are provided at diagonal positions of the lens holder 16. Similarly to the focus coils 33 and 34, the tracking coils 35 and 36 are wound in a substantially ring shape, and are provided at diagonal positions different from the focus coils 33 and 34, respectively. Sub-tracking coils 37 and 38 are provided between the focus coils 33 and 34 and the lens holder 16, respectively. By providing the sub-tracking coils 37 and 38, an unnecessary inclination of the lens holder 16 generated during tracking can be suppressed. The sub-tracking coils 37 and 38 are bonded to the lens holder 16 with an organic adhesive such as a thermosetting adhesive, and then the focus coils 33 and 34 are bonded to the sub-tracking coils 37 and 38 with an adhesive or the like. In addition, for example, a method in which a joined body in which the sub-tracking coil 37 and the focus coil 33 are joined in advance may be adhered to the lens holder 16. For the bonding between these coils and the lens holder 16 or between the coils, a thermosetting adhesive is preferably used. However, bonding using a photocurable adhesive or other adhesive is also possible. It can be implemented. In addition, as long as the coil, the lens holder 16, and the coils can be reliably arranged at predetermined positions, they may be joined using other methods.

  Three suspensions 18 are provided on one side so as to sandwich the lens holder 16, and the suspension 18 elastically connects the suspension holder 17 and the lens holder 16, and at least the lens holder 16 is within a predetermined range. The suspension holder 17 can be displaced. In the present embodiment, three suspensions 18 are provided on one side, for a total of six. However, even if a larger number (for example, eight) of suspensions 18 is provided, the number of suspensions 18 (for example, four) is less than that. ) Suspension 18 may be provided. For convenience, the upper three suspensions 18 in FIG. 6 are the suspensions 18a, 18b, and 18c from the side facing the optical disc 2, and the lower three suspensions 18 in FIG. 18e and 18f. Both ends of the suspension 18 are fixed to the lens holder 16 and the suspension holder 17 by insert molding, respectively.

  Hereinafter, an example of wiring between the suspension 18 and each coil provided in the lens holder 16 will be described. That is, a current flows through each suspension provided in the lens holder 16 via the suspension 18.

  Both ends of the focus coil 33 are electrically connected to the suspensions 18a and 18b, respectively, and both ends of the focus coil 34 are electrically connected to the suspensions 18d and 18e, respectively. The tracking coil 35, the sub-tracking coil 37, the tracking coil 36, and the sub-tracking coil 38 are connected in series, and one end of each of the series connected coils is connected to the suspension 18c, and the other is connected to the suspension 18c. Connected to the suspension 18f. The ends of the coils and the suspension 18 are electrically connected to each other by a metallic bonding material such as solder or lead-free solder.

  The suspension 18 may be configured by a wire having a substantially circular cross section, a substantially elliptical shape, or a polygonal shape such as a rectangular cross section, or may be formed as a suspension 18 by processing a leaf spring. The suspension 18 is substantially C-shaped when viewed from the light emission direction of the objective lenses 10 and 13 with the suspension holder 17 facing down, and tension is applied. This makes it possible to reduce the size and resonance of the suspension 18 in the buckling direction.

  Reference numeral 32 denotes a yoke member made of Fe or an Fe alloy that can easily form a magnetic circuit, and the yoke member 32 is cut and raised by standing portions 32a, 32b, and 32c facing the respective coils provided on the lens holder 16. For example, the yoke member 32 is integrally provided. An opening 32d is provided on the lower surface of the yoke member 32, and the rising mirrors 9 and 12 fixed to the base 15 are inserted from the opening 32d. The suspension holder 17 is fixed on the yoke member 32 by a technique such as adhesion, and the yoke member 32 is also joined to the base 15 by a technique such as adhesion.

  Reference numerals 39 to 42 denote magnets provided on the yoke member 32 by a technique such as adhesion.

  The magnet 39 is attached to the standing portion 32 c and is provided to face the focus coil 33 and the sub-tracking coil 37. Further, the magnet 39 has a magnetic pole exposed on the surface facing the focus coil 33 and the sub-tracking coil 37 in the order of S pole and N pole from the bottom surface toward the objective lenses 10 and 13 in the height direction shown in FIG. Thus, the yoke member 32 is magnetized.

  In the width direction shown in FIG. 6, the magnet 40 is attached to the side opposite to the side where the magnet 39 is attached of the standing portion 32 c and is provided so as to face the tracking coil 35. In this embodiment, the standing portion 32c is formed wide in the width direction shown in FIG. 6 so as to increase the rigidity and the like of the yoke member 32. However, the standing portion 32c is divided into two, and one of them is a magnet. It is good also as a structure which attached 39 by adhesion | attachment etc. and attached the magnet 40 to the other. Further, the magnet 40 is magnetized so that the magnetic poles are exposed on the surface facing the tracking coil 35 in the order of N pole and S pole from the inside in the width direction shown in FIG. .

  The magnet 41 is attached to the standing portion 32b and is provided so as to face the tracking coil 36. In the width direction shown in FIG. 6, a magnetic pole is formed on the surface facing the tracking coil 36 in order of N pole and S pole from the inside. It is magnetized so as to be exposed and disposed on the yoke member 32.

  The magnet 42 is attached to the standing portion 32 a and is provided to face the focus coil 34 and the sub-tracking coil 38. Further, the magnet 42 has magnetic poles exposed on the surface facing the focus coil 34 and the sub-tracking coil 38 in the order of S pole and N pole from the bottom surface toward the objective lenses 10 and 13 in the height direction shown in FIG. Thus, the yoke member 32 is magnetized.

  Details of each part will be described below.

  First, the short wavelength optical unit 1 will be described with reference to FIGS. Note that FIG. 9 is illustrated so that the arrangement relationship of each part is clear, and FIG. 10 is a cross-sectional view of the actual short wavelength optical unit 1.

  At least the light source unit 1a, the light receiving unit 1b, the light receiving unit 1c, and the optical member 1d are directly or indirectly attached to the mounting unit 43. Further, the rear end portion of the placement portion 43 is attached to the holding member 44. The mounting portion 43c of the mounting portion 43 with the holding member 44 has a convex curved shape, and similarly, the mounting portion of the holding member 44 with the mounting portion 43 has a concave curved shape. The mounting portion 43 is combined with the holding member 44 and is positioned so as to have a desired positional relationship with each other by sliding the curved portions, and thereafter, a metal adhesive such as solder or an organic adhesive Fixed to each other.

  The mounting unit 43 is provided with a light source storage unit 43a that can store at least a part of the light source unit 1a. After the light source unit 1a is stored in the light source storage unit 43a, the light source unit 1a is a light source using a bonding material. It joins so that it may not drop from storage part 43a. In addition, a through hole 43b is provided in a portion facing the light emitting part of the light source part 1a so as to communicate with the light source storage part 43a, and light emitted from the light source part 1a passes through the through hole 43b and enters the optical member 1d. Led. As will be described later in detail, the optical member 1d includes at least an optical unit 46 having an inclined surface 46a and an optical unit 47 having a plurality of inclined surfaces therein. The mounting portion 43 is integrally formed with a light receiving attachment portion 48 facing the optical member 1 d, and a through hole 45 is provided in the light receiving attachment portion 48. On the opposite side of the light receiving attachment portion 48 from the optical member 1d side, the light receiving portion 1b is attached through a flexible printed circuit board 49 by a technique such as adhesion. Although the flexible printed circuit board 49 is omitted and described in FIG. 9 and FIG. 10, etc., the light receiving portion 1b is electrically connected to other members, and a through hole 49a is provided. The light from the optical member 1d is guided to the light receiving unit 1b through the through holes 45 and 49a. Further, as apparent from FIG. 10, the light receiving attachment portion 50 is integrally provided on the mounting portion 43 so as to face the light receiving attachment portion 48, and the optical member 1 d is interposed between the light receiving attachment portions 48 and 50. Be placed. Although not illustrated in the light receiving attachment portion 50, a through hole is provided, and the light receiving portion 1c is attached to the light receiving attachment portion 50 by a technique such as adhesion. Light from the optical part 46 passes through a through hole of the light receiving attachment part 50 (not shown) and enters the light receiving part 1c.

  Next, the optical parts 46 and 47 of the optical member 1d will be described in detail with reference to FIG.

  The light having a short wavelength emitted from the light emitting point of the light source unit 1a is guided to the optical unit 46 through the cover glass 51 provided in the portion serving as the light emission window of the light source unit 1a. The light incident on the flat surface 46b provided substantially parallel to the cover glass 51 of the optical unit 46 passes through the optical unit 46, and the light incident on the inclined surface 46a inclined with respect to the flat surface 46b is reflected and is shown in FIG. Is incident on a light receiving unit 1c not shown, and is used for monitoring optical output. A reflective portion such as a dielectric multilayer film or a metal film is formed on the inclined surface 46a. Most of the light passing through the optical unit 46 is guided to the optical unit 47 through the plane 46c provided substantially parallel to the plane 46b. At this time, although not shown in the drawing, a dimming filter is formed on the flat surface 46 c, and the light dimmed by the dimming filter is guided to the optical unit 47. The transmittance of the neutral density filter has various values, and the transmittance is adjusted by the spread angle of the light emitted from the light source unit 1a. That is, when the spread angle of light from the light source unit 1a is large, the transmittance of the dimming filter is low, and when the spread angle of light from the light source unit 1a is small, the transmittance of the dimming filter is increased. Configure as follows. In this way, by adjusting the transmittance of the light control filter according to the spread angle of the light from the light source unit 1a, the light output is too strong during recording or reproduction of a single-layer disc or a multilayer disc, and undesired data erasure Can be prevented. Specifically, the spread angle of light emitted from the light source unit 1a is classified in advance for each predetermined range, and a dimming filter having a different transmittance is provided for each classified light source unit 1a, so that the optical disc is And good recording / reproducing characteristics can be obtained. The dimming filter is composed of a dielectric multilayer film or a metal film, and when adjusting the transmittance, when using a dielectric multilayer film, it can be adjusted by its constituent material, film configuration or film thickness. When a metal film is used, the constituent material and thickness of the metal film can be adjusted.

  The light that has passed through the plane 46 c enters the optical unit 47. At this time, a gap having a predetermined interval is provided between the optical unit 46 and the optical unit 47. The optical part 47 has a substantially rectangular parallelepiped shape as a whole, and a light absorption film having a light absorption function is provided on a bottom surface 53 on which light from the light source part 1a is incident, except for a predetermined region. This prevents the light emitted from the light source unit 1a from entering the optical unit 47 from a place other than the predetermined portion. At least a part of the light emitted from the light source unit 1 a and passed through the optical unit 46 enters the optical unit 47 from a portion where the absorption film on the bottom surface 53 is not disposed.

  The optical unit 47 is configured by joining blocks 58 to 61 made of transparent glass or the like, and an inclined surface 54 is formed at a joint portion between the block 58 and the block 59, and between the block 59 and the block 60. An inclined surface 55 is formed, and an inclined surface 56 is formed between the block 60 and the block 61. At least inclined surfaces 54, 55, and 56 are provided inside the optical unit 47, and end portions of the inclined surfaces 54, 55, and 56 are exposed on the surface of the optical unit 47. The inclined surface 54 is provided with a first polarizing beam splitter, and the inclined surface 55 is similarly provided with a second polarizing beam splitter. The first and second polarizing beam splitters are both formed directly on the block 59, but the first polarizing beam splitter may be formed on the block 58, or the second polarizing beam splitter may be formed on the block 60. May be. Both the first and second polarization beam splitters have a function of transmitting P-polarized light (hereinafter abbreviated as P wave) and reflecting S-polarized light (hereinafter abbreviated as S wave). In addition, at least the first and second polarization beam splitters may be provided in a portion through which light mainly passes in the optical unit 47, but in the case of the present embodiment, the inclined surfaces 54, 55 was provided on the entire surface. On the inclined surface 56, a reflection film and a hologram 57 (same as the hologram 1e shown in FIG. 1) for generating astigmatism are formed.

  Light that has entered the optical unit 47 through the bottom surface of the optical unit 47 from the light source unit 1 a is an S wave, is reflected by the first polarizing beam splitter provided on the inclined surface 54, and is formed on the inclined surface 55. The light is incident on the second polarization beam splitter. As described above, the second polarizing beam splitter also reflects the S wave, so that the light incident on the second polarizing beam splitter is reflected and emitted from the upper surface 62z of the optical unit 47, and passes through the above-described members. To the optical disc 2. Further, the light reflected by the optical disk 2 is converted into a P wave by the action of the quarter wavelength member 9 a and enters the optical unit 47 again from the upper surface 62 z of the optical unit 47. At this time, the emission part of the light directed from the optical unit 47 toward the optical disk 2 and the incident part of the reflected light reflected from the optical disk 2 are substantially at the same position. Since the light reflected from the optical disk 2 and returned to the optical unit 47 is a P wave as described above, the second polarization beam splitter provided on the inclined surface 55 is transmitted and incident on the inclined surface 56. The inclined surface 56 is provided with a reflection hologram 57 that generates astigmatism, and the reflected light from the optical disc 2 is separated in a predetermined direction by the hologram 57 so that a focus error signal can be obtained. Since the light reflected by the inclined surface 56 is a P wave, it passes through the second polarizing beam splitter again, passes through the block 59, and as described above, the first polarizing beam splitter also transmits the P wave. Therefore, the light passes through the first polarizing beam splitter, passes through the block 58, is emitted to the outside of the optical unit 47, and then enters the light receiving unit 1b.

  Next, an example of the light source unit 1a will be described with reference to FIGS.

  As shown in FIGS. 12 and 13, the light source unit 1a is composed of the following members. First, a base 62 made of a metal material is provided, and concave portions 62a used for adjusting the position of the light source unit 1a and the like are provided on both short sides of the base 62. Further, through holes 62b and 62c are provided. Although not shown in the drawing, another through hole is provided in addition to the through holes 62b and 62c. A cover member 63 is joined to the base 62 by welding, soldering, or the like. A square through hole 64 is provided on the top surface of the cover member 63, and a cover glass 65 (see FIG. 11) is formed so as to close the through hole 64. The same as the cover glass 51) is attached by a technique such as adhesion. The cross section of the cover member 63 is an ellipse or an ellipse. In addition, a block 66 such as copper or a copper alloy, preferably having good thermal conductivity, is provided in a region surrounded by the base 62 and the cover member 63, and the block 66 is joined to the base 62 by welding or a metal joining material. Has been. The cross section of the block 66 has a substantially semicircular shape. A semiconductor laser element 68 is provided on a flat portion of the block 66 via a submount 67 made of a metal material. Accordingly, the submount 67 and the semiconductor laser element 68 are disposed in the region surrounded by the base 62 and the cover member 63 together with the block 66. The light emitting surface of the semiconductor laser element 68 is disposed so as to face the cover glass 65 and is emitted from the cover glass 65 to the outside. Rod-like terminals 69, 70, 71 are inserted into the through holes 62b, 62c provided in the base 62 and the other through holes, respectively, and the terminals are provided so as to maintain insulation between the base 62 and the terminals 69, 70, 71. The through holes 62b, 62c of 69, 70, 71 and the portions inserted into the other through holes are attached to the base 62 via an insulating material. The tip portions of the terminals 69, 70, 71 protrude into a region surrounded by the base 62 and the cover member 63. Although not shown, between the semiconductor laser element 68 and the terminals 69, 70, 71 by wire bonding or the like. Make electrical connections. Accordingly, power is supplied to the semiconductor laser element 68 via the terminals 69, 70, 71, and light having a short wavelength is emitted.

  As described above, the semiconductor laser element 68 is preferably a gallium nitride based semiconductor laser element in which an active layer (gallium nitride having an emission center such as In) is basically provided between p-type gallium nitride and n-type gallium nitride. Used to emit light having a wavelength of 400 nm to 415 nm. As a matter of course, other material-based semiconductor laser elements that emit other short-wavelength lasers can also be used.

  The semiconductor laser element 68 has a rectangular parallelepiped shape with a rectangular cross section, and since the long side portion of the cross sectional rectangle is joined to the submount 67, the long side 62d of the base 62 and the length of the cross sectional rectangle of the semiconductor laser element 68 are long. The side direction P is non-parallel (in the present embodiment, it intersects substantially vertically). With such a configuration, the cross section of the light emitted from the semiconductor laser element can be emitted so that the major axis of the intensity distribution of the substantially elliptical radiation light and the long side 62d of the base member 62 are substantially parallel. . For example, as shown in FIG. 14, 72 is an axis substantially parallel to the long side 62 d of the base 62, and 74 is an outline of light indicated by a line with constant intensity, indicating the intensity distribution of light emitted from the semiconductor laser element. , 73 are substantially elliptical long axes of the contour 74 of the emitted light. In the present embodiment, as shown in FIG. 14A, the angle θ at which the shaft 72 and the long axis 73 intersect is 90 degrees. Instead, as shown in FIGS. 14B and 14C, the angle θ is not 90 degrees. Note that the angle θ is defined as the minimum angle at which the axis 72 and the long axis 73 intersect. That is, the angle θ is not less than 0 degrees and not more than 90 degrees. That is, as shown in FIG. 14B, the axis 72 and the long axis 73 are parallel, and as shown in FIGS. 14B to 14F, the long axis 73 and the axis 72 intersect at a predetermined angle θ. ing. At this time, the intersecting angle θ is preferably 0 ° or more and 45 ° or less, more preferably 0 ° or more and 30 ° or less, and further preferably 0 ° or more and 10 ° or less. Naturally, as shown in FIG. 14B, it is most preferable that the major axis 73 and the axis 72 are substantially parallel (the angle θ is substantially 0 degree). In the above example, the shaft 72 is parallel to the long side 62d of the base 62. However, the shaft 72 can also be defined in relation to other components as described below. That is, the axis 72 can be defined as being an axis parallel to the main surface of the mounted optical disk 2 and perpendicular to the direction of the light emitted from the cover glass 65 of the light source unit 1a. It can also be defined that the axis is perpendicular to the thickness direction of the base 15 shown and is also perpendicular to the direction of the light emitted from the cover glass 65 of the light source unit 1a, and is parallel to the bottom surface of the base 15 and also the light source unit 1a. It can also be defined that the axis is perpendicular to the direction of light emitted from the cover glass 65. Furthermore, it can also be defined as an axis perpendicular to the rotation axis of the spindle motor 25 and perpendicular to the direction of light emitted from the cover glass 65 of the light source unit 1a.

  In this way, by making the long axis of the outer ring of the light emitted from the light source unit 1a as described above, the light utilization efficiency can be increased, and the light source unit 1a having the same output can be used. For example, if the optical disk 2 can be irradiated with light having a higher output and the intensity of the light applied to the optical disk 2 is the same, the light source unit 1a having a lower output can be used.

  Hereinafter, the principle will be described in detail with reference to FIG.

  FIG. 15A shows a case where the axis 72 and the long axis 73 intersect perpendicularly, that is, a case where a vertically long oval shape is formed in the drawing. In this case, an area up to a portion having a predetermined amount of light when the light quantity at the center Q of the light outline 74 (a point where the major axis and the minor axis intersect) is 1 in the direction along the axis 72. Of light is used. That is, for example, in the present embodiment, the predetermined ratio is 0.6 (this ratio is determined depending on the specification, etc., but is generally 0.3 to 0.8). The light in the circular region 75 of the distance, that is, the circular region 75 having a diameter of L1 + L2 can be used. In this embodiment, since L1≈L2, the region of light that is substantially used is a circular region 75 having a radius of L1 or L2. In the case of FIG. 15A, since it is vertically long, in the direction of the axis 72, the distances L1 and L2 at which the light quantity from the center Q to the center Q becomes 0.6 are relatively short and can be used. There is a small amount of light. On the other hand, as in the optimum embodiment shown in FIG. 15B, the light in the region up to the portion where the light amount is a predetermined ratio is used. That is, for example, in the present embodiment, the predetermined ratio is 0.6 (this ratio is determined depending on the specification or the like, but is usually 0.3 to 0.8), and L3 and L4 from the center Q to the left and right. The light in the circular region 75 of the distance, that is, the circular region 75 having a diameter of L3 + L4 can be used. In this embodiment, since L3≈L4, the region of light that is substantially used is a circular region 75 having a radius of L3 or L4. In the case of FIG. 15B, since the light outline 74 is horizontally long, in the direction of the axis 72, the distances L3 and L4 at which the light amount from the center Q to the center Q becomes 0.6 are relatively long. Therefore, the available light amount area is very wide compared to the example of FIG. 15A, and light can be used efficiently. That is, L1 <L3 and L2 <L4.

  In the present embodiment, as described above, the configuration in which the major axis 73 of the substantially elliptical light emitted from the light source unit 1a is not perpendicular to the axis 72 but is a predetermined angle θ (including 0 degrees) is shown in FIG. 12 and 13, the long side 62 d of the base 62 is attached to the base 15 side, so that the long axis of the elliptical light emitted from the light source unit 1 a is set to the base 15 as described above. Since it can be made substantially parallel and the height of the light source unit 1a is not increased, the apparatus can be made thinner. In the optical disk apparatus of 18 mm or less, preferably 15 mm or less, more preferably 13 mm or less assumed in the present embodiment, it is very preferable to mount the light source unit 1a low in realizing these optical disk apparatuses. It can be said. Further, when the shaft 72 and the long shaft 73 are set to a predetermined angle (greater than 0 degree and less than 90 degrees), the light source unit 1a itself is rotated by a predetermined angle (in this case, the light source unit 1a is somewhat attached) Or the block 66 in the light source section 1a is rotated by a predetermined amount to be attached to the base 62, or when the semiconductor laser element 68 is attached to the block 66, the long side 62d is inclined. It can be realized by attaching.

  Next, the long wavelength optical unit 3 will be described with reference to FIG.

  The mounting unit 76 is provided with a light source holding unit 76a. The light source unit 3a is joined to the light source holding unit 76a with a bonding material such as solder, lead-free solder, or a photocurable resin. An optical member 3d is attached on the light source holding part 76a. Further, the light receiving portions 3b and 3c are attached to the mounting portion 76 with a bonding material such as a photo-curing resin so as to sandwich the optical member 3d. The light source unit 3 a covers at least a part of the lead frame 77 with a molding member 78 such as a resin, and a semiconductor laser element 79 is mounted on the lead frame 77. Terminals 77 a to 77 c are electrically connected to the lead frame 77. As described above, the semiconductor laser element 79 emits light having a wavelength of 640 nm to 800 nm, and emits a single type of light or emits a plurality of types of light. . In the present embodiment, a light beam having a wavelength of about 660 nm (red: for example for DVD) and a light beam of about 780 nm (for infrared: for example, for CD) are emitted. The semiconductor laser element 79 is a monoblock element that emits two light beams. However, a device that emits one light beam in one block may be provided on a plurality of lead frames 77.

  The optical member 3d is composed of two optical units 80 and 81, and the optical unit 80 is plate-shaped, so that unnecessary light emitted from the light source unit 3a does not reach the optical unit 81 (not shown), that is, A film for preventing stray light is formed. That is, the film for preventing stray light has an opening, and a main part of the light is guided to the optical unit 81 through the opening, and light incident on the part other than the opening is absorbed. In addition, a hologram having a wavelength selectivity that acts on CD-compatible light and hardly acts on DVD-compatible light is provided, and the CD-compatible light is separated into three beams by this hologram. The optical unit 81 is provided on the optical unit 80, and the optical unit 81 is configured by joining blocks 82 to 85 made of transparent glass or the like, and an inclined surface is formed at a joint portion between the block 82 and the block 83. 86 is formed, an inclined surface 87 is formed between the block 83 and the block 84, and an inclined surface 88 is formed between the block 84 and the block 85. At least inclined surfaces 86, 87, 88 are provided inside the optical unit 81, and ends of the inclined surfaces 86, 87, 88 are exposed on the surface of the optical unit 81.

  The inclined surface 86 is provided with at least one of a reflection film and a hologram on a part of the light transmission part so as to reflect 3 to 15% of the light emitted from the light source unit 3a, and is compatible with CD. A dielectric multilayer film is formed which transmits the P wave of the light and the DVD compatible light and reflects the S wave. The light reflected by the inclined surface 86 enters the light receiving unit 3c and is used for controlling the light output of the light source unit 3a. Further, the inclined surface 87 is provided with a dielectric multilayer film that transmits the P wave of CD-compatible light and DVD-compatible light, reflects the S wave of CD-compatible light, and transmits the S wave of DVD-compatible light. Is formed. The inclined surface 88 is provided with a dielectric multilayer film or a metal film having a reflecting action. In the present embodiment, the inclined surface 88 is provided with a reflective hologram 3e.

  When the CD-corresponding light emitted from the light source unit 3 a is incident on the optical unit 80, the stray light portion is removed and the light is separated by a hologram having wavelength selectivity, and becomes three beams on the optical disc 2. Further, when the light enters the optical unit 81 from the optical unit 80, a part of the light is reflected by the inclined surface 86 and is incident on the light receiving unit 3c. The light is incident on 83 and guided to the inclined surface 87. The light corresponding to the CD, which is a P wave, passes through the inclined surface 87, passes through the block 84, and is emitted from the upper surface of the block 84. Further, the light reflected by the optical disk 2 becomes an S wave by the action of the quarter wavelength member of the optical component 11, and is incident on the upper surface of the block 84 again and is incident on the inclined surface 87. Since the inclined surface 87 is provided with a film having a function of reflecting the S wave of CD-compatible light, the CD-compatible light reflected from the optical disc 2 is reflected and reflected by the inclined surface 88, and further blocked. Then, the light passes through 84 and enters the inclined surface 87 again. As described above, the inclined surface 87 is provided with the film for reflecting the S wave of light corresponding to the CD, so that it is reflected again by the inclined surface 87, passes through the block 84, and is guided to the light receiving unit 3 b. The light incident on the light receiving unit 3b is converted into an electric signal, and an RF signal, a tracking error signal, a focus error signal, and the like are generated. The reflected hologram 3e provided on the inclined surface 88 separates the reflected light from the optical disk 2 into a plurality of light beams, which are respectively guided to predetermined locations on the light receiving unit 3b to generate a focus error signal.

  When the DVD-compatible light emitted from the light source unit 3 a enters the optical unit 80, the stray light portion is removed and enters the optical unit 81. The hologram having wavelength selectivity provided in the optical unit 80 does not act on DVD-compatible light. When the light enters the optical unit 81 from the optical unit 80, a part of the light is reflected by the inclined surface 86 and incident on the light receiving unit 3c, and the other light passes through the inclined surface 86 and enters the block 83. Guided to face 87. On the inclined surface 87, the DVD-compatible light is a P wave, so that it passes through the block 84 and is emitted from the upper surface of the block 84. Further, the light reflected by the optical disk 2 becomes an S wave and again enters the upper surface of the block 84 and enters the inclined surface 87. Since the inclined surface 87 is provided with a film having a function of allowing the DVD-compatible light to pass through, the DVD-compatible light reflected from the optical disc 2 passes through the inclined surface 87 and further passes through the block 83 to be inclined. 86 is incident. Since the inclined surface 86 reflects S-wave light corresponding to DVD, the DVD-compatible light is reflected, passes through the block 83, and enters the inclined surface 87 again. As described above, the inclined surface 87 is compatible with DVD. Since a film through which light passes is formed, the light passes through the inclined surface 87 and is guided to the light receiving unit 3b. The light incident on the light receiving unit 3b is converted into an electric signal, and an RF signal, a tracking error signal, a focus error signal, and the like are generated.

  In FIG. 16, a round trip path of light corresponding to CD is shown.

  Next, the beam shaping lens 4 used in this embodiment will be described.

  As shown in FIG. 17, the beam shaping lens 4 includes a light transmission part 4d including a convex part 4a and a concave part 4b and a mounting part 4c provided so as to sandwich the light transmission part 4d. Although the mounting portion 4c is integrally formed in the present embodiment, the light transmitting portion 4d and the mounting portion 4c may be configured as separate members and bonded to each other with an adhesive or the like.

  As shown in FIG. 17A, short-wavelength light emitted from the short-wavelength optical unit 1 has an elliptical shape immediately before entering the beam shaping lens 4, but the convex portions 4a and the concave portions 4b By setting the curvature radius or a predetermined curved surface shape, the light becomes a substantially circular light after passing through the beam shaping lens 4. Similarly, the light reflected by the optical disk 2 or the like passes through the beam shaping lens 4 so that the circular light is converted into a substantially elliptical shape.

  Next, the optical component 5 used in this embodiment will be described with reference to FIG.

  The optical component 5 has a substantially square shape made of transparent glass or the like, and is configured by sandwiching the polarizing portion 5c and the polarizing portion 5d between the plate-like substrates 5a and 5b. The polarizing unit 5 c acts greatly on the S wave emitted from the short wavelength optical unit 1 and hardly acts on the P wave reflected by the optical disc 2. Further, the polarization unit 5 d hardly acts on the S wave emitted from the short wavelength optical unit 1, and acts largely on the P wave reflected by the optical disc 2. For the optical component 5, the light emitted from the short wavelength optical unit 1 passes through the substrate 5a, the polarizing unit 5c, the polarizing unit 5d, and the substrate 5b in this order, and the light reflected by the optical disc 2 is the substrate 5b and polarized light. It passes through the part 5d, the polarizing part 5c, and the substrate 5a in this order. As shown in FIG. 18B, the polarization portion 5c is formed with a polarization-selective hologram 5e in a substantially square shape using an optically anisotropic resin material. As shown in FIG. 18B, the hologram 5e is formed in a rectangular shape and is configured such that the end of the incident light beam diameter protrudes from the long side. Although not shown, the polarization portion 5c is configured by filling the hologram 5e with at least an optically isotropic resin. As one of the manufacturing methods, a hologram 5e is produced on a substrate 5a by a known method, and at least a gap of the hologram 5e is filled with an optically isotropic resin. As shown in FIG. 18C, on the X axis in FIG. 18B, the amount of incident light is indicated by a dotted line, and when passing through the polarizing portion 5c, the amount of light generally decreases as shown by a solid line. Further, as shown in FIG. 18 (d), the incident light quantity is indicated by a dotted line on the Y axis in FIG. 18 (b), and when passing through the polarizing portion 5c, the incident light is mainly incident as shown by the solid line. The configuration is such that a large amount of light is dropped. Thus, by dropping a portion with a large amount of light at the polarizing portion 5c, the RIM intensity (the intensity ratio of the outermost light flux with respect to the center intensity) can be increased, and short-wavelength light is condensed at a small spot on the optical disc 2. Therefore, at least one of recording / reproduction on the high-density optical disc 2 can be performed. That is, the polarization unit 5c has a function of a RIM intensity correction filter that does not act in the X-axis direction where the RIM intensity is high but acts only in the Y-axis direction where the RIM intensity is low.

  Further, in the polarizing portion 5d, a polarization selective hologram is provided on the substrate 5b, although not shown with an optically anisotropic resin material, and is configured by filling the hologram with an isotropic resin. . The hologram that constitutes a part of the polarization unit 5d has a function of separating the light reflected from the optical disc 2 into a predetermined light flux so as to mainly generate a tracking error signal.

  Further, as one of the manufacturing methods, polarizing portions 5c and 5d are formed on the substrates 5a and 5b, respectively, and the polarizing portions 5c and 5d are opposed to each other, and are bonded with an adhesive such as a resin therebetween. In this way, the optical component 5 is formed.

  Next, the relay lens 6 will be described in detail.

  Specifically, the relay lens 6 has a shape as shown in FIG. That is, a light transmitting portion 6a through which light passes substantially at least partially, a plurality of protrusions 6b provided around the light transmitting portion 6a, and preferably provided radially, and an outer angle provided with the protrusions 6b. In this embodiment, the light transmission part 6a, the protrusion 6b, and the outer ring part 6c are integrally formed. However, each part is constituted by a separate piece, and each part is formed. May be attached to each other.

  A mounting portion 15a is erected on the base 15, and a concave portion 15b having a step portion 15c is provided on the mounting portion 15a. The relay lens 6 is inserted from the insertion direction shown in FIG. The relay lens 6 is configured not to drop off to the long wavelength optical unit 3 side by the concave portion 15b provided with the step portion 15c. Although not shown, a through hole is provided in the portion of the inserted relay lens 6 that faces the light transmission portion 6a. Accordingly, as shown in FIG. 19, the light emitted from the long wavelength optical unit 3 sequentially passes through the light transmission part 6 a and the through holes provided in the attachment part 15 a and is directed toward the beam splitter 7.

  Also, an astigmatism can be corrected by an operator, an automatic adjustment device, or the like by bringing a thin pin or the like (not shown) into contact with the projection 6b and displacing the relay lens 6 by a predetermined angle. Further, since the outer ring portion 6c substantially contacts the inner wall of the recess 15b, and the outer ring portion 6c has some protrusions and recesses, but the outer shape is substantially circular, the relay lens 6 is It is held rotatably by a thin pin or the like. After correcting the astigmatism by rotating the relay lens 6 by a predetermined angle, the relay lens 6 is cured by providing an instantaneous adhesive or a photo-curable adhesive over at least the relay lens 6 and the mounting portion 15a. The attachment portion 15a is fixed. At this time, it is preferable that an adhesive is provided in the recess 15b in the mounting portion 15a. Further, an application method and an application amount of the adhesive are taken into consideration so that the adhesive is not substantially applied to the light transmitting portion 6a. It is preferable.

  Next, the beam splitter 7 will be described in detail.

  As shown in FIG. 20, the outer shape of the beam splitter 7 is configured to be a substantially rectangular parallelepiped shape or a substantially cubic shape, and is configured by joining the transparent members 7b and 7c as described above, and by joining the transparent members 7b and 7c. It has the inclined surface 7a formed. As shown in FIG. 20, the inclined surface 7a is formed at an angle of about 45 degrees with respect to the bottom surface 7f of the side surface. However, according to the specifications and the outer shape of the beam splitter 7, the inclined surface 7a has a predetermined angle. It is determined appropriately. The transparent members 7b and 7c are formed in a substantially triangular prism shape with a glass material such as BK7. As shown in FIG. 20, the inclined surface has a laminated portion 7d and a joint portion 7e.

The laminated portion 7d is configured by alternately laminating low refractive index films and high refractive index films. In this embodiment, SiO ₂ is used as the low refractive index film, and Ta ₂ O ₅ is used as the high refractive index film. Used to configure. Moreover, each film thickness of the high refractive index film | membrane and the low refractive index film | membrane was about 10 nm-400 nm. In the present embodiment, the surface on which the laminated portion 7a of the transparent member 7c is provided is preferably subjected to a polishing process or a surface treatment, and then a thin film forming technique such as sputtering or vapor deposition is used for SiO ₂ , Ta ₂ O _5. , SiO ₂ , Ta ₂ O ₅ ,..., SiO ₂ , Ta ₂ O ₅ , SiO ₂ are laminated in this order to form a laminated portion 7d. In this embodiment, 20 or more pairs of thin films of SiO ₂ film and Ta ₂ O ₅ film are stacked (preferably 35 sets or less in consideration of yield and manufacturing cost). When calculating each of the SiO ₂ film and the Ta ₂ O ₅ film as one layer, the laminated portion 7d is composed of 40 to 70 layers. Further, it is advantageous in terms of characteristics and productivity that the actual thickness of the laminated portion 7d is 2 to 10 μm.

When the stacked portion 7d is configured in this way, by adjusting the formation film thickness of each layer (in the above-described case, the SiO ₂ film and the Ta ₂ O ₅ film), light of a predetermined wavelength is transmitted and other wavelengths are transmitted. It is possible to have a function of reflecting the light. In the present embodiment, the laminated portion 7d transmits red light (light having a wavelength of approximately 660 nm) and infrared light (light having a wavelength of approximately 780 nm) and reflects a short wavelength (light having a wavelength of approximately 405 nm). It was.

  A joint 7e is provided between the laminated part 7d and the transmissive member 7b, and a Si-based adhesive is preferably used for the joint 7e. Si-based adhesives have the property of not easily deteriorating with respect to light having a short wavelength, and are very preferable in an optical pickup device using light having a wavelength of about 405 nm as in this embodiment. As a matter of course, the joint 7e may be made of glass or other resin material. By setting the thickness of the bonding portion 7e to 3 to 15 μm (preferably 8 to 12 μm), reliable bonding between the transparent members 7b and 7c can be realized, and productivity can be improved. Further, the feature of the present embodiment is that the light having a short wavelength is incident from the bottom side 7f side, so that the laminated portion 7d is provided on the transparent member 7c without the joint portion 7e. It can suppress that the junction part 7e deteriorates with the light of a short wavelength.

  Next, the collimator lens 8 and its driving device will be described.

  As shown in FIG. 21, a lead screw 8c, a gear group 8d, and a drive member 8e are fixed to the base 89. In the present embodiment, a stepping motor is used as the driving member 8e. A motor gear 90 is fixed to the rotation shaft of the drive member 8e. A train shaft 91 is rotatably attached to the base 89. A train gear 92 is fixed to the train shaft 91, and a motor gear 90 is engaged with the train gear 92. The base 89 is integrally provided with a pair of attachment portions 89a and 89b. One end of the screw shaft 8c is rotatably held by the attachment portion 89a, and the other end of the screw shaft 8c is attached to the attachment portion 89b. It is inserted freely. A shaft gear 93 is fixed to the end portion on the attachment portion 89b side, and the shaft gear 93 meshes with the train gear 92. That is, by the rotation of the driving member 8e, the rotational driving force is transmitted to the screw shaft 8c via the gear group 8d (motor gear 90, train gear 92, shaft gear 93).

  As described above, the driving device 94 on which the above-described members are mounted is attached to the base 15. As shown in FIG. 22, a slider 8 b on which a collimator lens 8 is mounted is movably attached to a pair of support members 8 a attached to the base 15. The drive device 94 is provided on the side of the support member 8a so that the screw shaft 8c of the drive device 94 and the support member 8a are substantially parallel to each other. A rack member 95 made of an elastic material such as a leaf spring is attached to the slider 8b by bonding, mechanical joining, or the like, and an end portion of the rack member 95 is a spiral groove provided in the screw shaft 8c. Are engaged. Therefore, the moving direction and speed of the slider 8b can be adjusted by the rotating direction and rotating speed of the screw shaft 8c. In the present embodiment, since the stepping motor is used for the driving member 8e, the position of the slider 8b, that is, the position of the collimator lens 8 can be determined by the number of pulses supplied to the driving member 8e.

  Although not shown, the case where at least one of recording / reproducing is performed on the optical disc 2 (having the first recording layer and the second recording layer) with the light from the short wavelength optical unit 1 and the long wavelength optical unit In the case where information is recorded / reproduced with respect to the optical disc 2 with CD-compatible light or DVD-compatible light emitted from the optical disc 2, at least a recording / reproduction operation in which the positions of the collimator lenses 8 are surely different from each other is ensured. This is a preferred form of doing one.

  Accordingly, when at least one of recording / reproducing is performed on the first recording layer of the optical disc 2 with the light from the short wavelength optical unit 1, the collimator lens 8 is positioned at the first position, and the short wavelength optical unit 1. When at least one of recording / reproducing is performed with respect to the second recording layer of the optical disc 2 by the light from the collimator lens 8, the collimator lens 8 is positioned at the second position and is compatible with the CD emitted from the long wavelength optical unit 3. When at least one of recording / reproduction with respect to the optical disk 2 is performed with light, the collimator lens 8 is positioned at the third position, and recording with respect to the optical disk 2 is performed with DVD-compatible light emitted from the long wavelength optical unit 3. / When performing at least one of reproduction, the collimator lens 8 is positioned at the fourth position. The first to fourth positions are positions of the collimator lens 8 within a range where the slider 8b can operate, and the first position and the second position are always different positions. The third position and the fourth position are at positions different from at least one of the first position and the second position, and are preferably located between the first position and the second position. At least two of the first position to the fourth position are different positions.

  An example of the operation according to the above configuration is shown.

  It is assumed that a separate sensor or the like (not shown) is provided and is located at the home position of the slider 8b by this sensor. A control member (not shown) determines, based on a signal from the outside, which wavelength of light is used for recording / reproduction, or whether recording / reproduction is performed on the first recording layer or the second recording layer. The number of pulses to be sent from the memory to the drive member 8e is read from the signal. At this time, the first to fourth positions are determined depending on which wavelength of light is used for recording / reproduction or whether recording / reproduction is performed on the first recording layer or the second recording layer. . In order to position the collimator lens 8 at each position, it is known to some extent at which time the slider 8b existing at the home position needs to be moved in which direction. By recording the number, the collimator lens 8 can be easily positioned at the optimum position (first to fourth positions). Note that the first position to the fourth position may coincide with the home position of the slider 8b. When the predetermined operation is completed, the control member causes the drive member 8e to send a pulse so as to return the slider 8b to the home position. FIG. 23 shows a state in which the collimator lens 8 and its driving device 94 are attached.

  Next, the achromatic diffraction lens 14 will be described.

  As shown in FIG. 24, the achromatic diffractive lens 14 has a light transmission part 14d and an outer ring part 14c that surrounds the outside of the light transmission part 14d, and is provided on the objective lens 13 side of the light transmission part 14d. The surface 14a is concave, and a hologram having a predetermined pitch and shape is provided on the surface 14b on the opposite side of the rising mirror 12 side. Essentially, light having a short wavelength is transmitted through the light transmitting portion 14d. In order to correct the chromatic aberration, desired chromatic aberration correction can be performed by adjusting the pitch of the hologram provided on the surface 14b. The achromatic diffraction lens 14 has a substantially circular shape, and the outer ring portion 14 c is attached to the lens holder 16. In the present embodiment, the light transmitting portion 14d and the outer ring portion 14c are integrally formed, but the light transmitting portion 14d and the outer ring portion 14c are formed as separate members. For example, the light transmitting portion 14d is provided at the center of the outer ring portion 14c. An embedded configuration may be used.

  Next, another embodiment of the lens holder 16 and the suspension holder 17 will be described with reference to FIGS. 6 and 7 have substantially the same function. 25 to 28 and FIGS. 6 and 7 have substantially the same functions as described above, the members shown in FIGS. 25 to 28 are the members shown in FIGS. The shape is slightly different.

  The lens holder 16 needs to increase the resonance frequency of the lens holder 16 when performing at least one of recording / reproduction with respect to the optical disc 2 at a high speed. That is, in order to control the lens holder 16 so as to follow the surface shake of the optical disk 2 of the lens holder 16 by recording / reproducing at a high speed, the resonance frequency of the lens holder 16 is increased to be equal to or less than the resonance frequency. It is preferable to control the lens holder 16 in the region. One method for increasing the resonance frequency of the lens holder 16 is to give the lens holder 16 high rigidity. In the present embodiment, in order to give the lens holder 16 high rigidity, all or at least a part of the lens holder 16 is made of a material in which fibers are dispersed in a resin (hereinafter abbreviated as a composite material). As the resin, liquid crystal polymer, epoxy resin, polyimide resin, polyamide resin, acrylic resin, etc. are suitably used, and as the fiber, metal fiber such as carbon fiber, carbon black, copper, nickel, aluminum, stainless steel, etc. In addition, these composite fibers are preferably used. In the present embodiment, the lens holder 16 is made of a material in which carbon fibers are dispersed in a liquid crystal polymer.

  As shown in FIGS. 25 and 26, when the lens holder 16 and the suspension holder 17 are made of the above composite material, the lens holder 16 and the suspension holder 17 may have conductivity, so that they are formed on the surfaces of the suspensions 18a to 18f. An insulating film was formed. In this case, an insulating member is provided between the lens holder 16 and the various coils to be insulated, or various coils are constituted by windings in which the windings themselves are insulated. As described above, by providing the suspensions 18a to 18f with the insulating coating, the insulation between the lens holder 16 and the suspension holder 17 having conductivity is maintained. Insulated end portions 98 and 99 of the suspensions 18a to 18f are attached to the bobbin suspension receiving portions 96 and 97 provided integrally with the lens holder 16 by insert molding. The insulated ends 100 and 101 of the suspensions 18a to 18f on the suspension holder 17 side are attached to the suspension holder 17 by insert molding. Further, the tip portions 102 and 103 on the lens holder 16 side of the suspensions 18a to 18f are not provided with an insulating film, and the tip portions 102 and 103 and various coils provided on the lens holder 16 are electrically connected. Furthermore, the tip portions 104 and 105 on the suspension holder 17 side of the suspensions 18a to 18f are not provided with an insulating film, and are connected to the tip portions 104 and 105 and a flexible printed board (not shown). .

  Further, as a modification of the embodiment shown in FIGS. 25 and 26, as shown in FIGS. 27 and 28, the end portions 106 of the suspensions 18a to 18f are provided without providing an insulating film on almost all of the suspensions 18a to 18f. , 107 is provided with an insulating film, and part or all of the end portions 106, 107 (in the case of all, consideration is given so that the lens holder 16 and the suspensions 18a to 18f are not in contact) with the bobbin suspension receiving portions 96, 97. To join. In the embodiment shown in FIGS. 27 and 28, a part of the end portions 106 and 107 are joined to the bobbin suspension receiving portions 96 and 97 in order to maintain insulation. Also, the end portions 108 and 109 on the suspension holder 17 side of the suspensions 18a to 18f are provided with an insulating film, and at least the end portions 108 and 109 and the suspension holder 17 are joined. In the embodiment shown in FIGS. The end portions 108 and 109 are all joined to the suspension holder 17.

  In addition, as the above-mentioned insulating film, an insulating material is produced using a technique such as coating, electrodeposition, and vapor deposition. As an insulating material, an insulating material such as an epoxy resin, silicon dioxide, or the like can be used. An inorganic insulating material is used. Further, the surface of the suspensions 18a to 18f having conductivity may be subjected to a treatment such as an oxidation treatment to provide an insulating film. Further, the suspension 18a to 18f may be inserted into a tube-shaped insulating material as an insulating film to form an insulating film, or a metal wire passed through a resin wire by insert molding or the like may be used as the suspension 18a to 18f. It is also good.

  As another embodiment, as shown in FIGS. 29 and 30, the suspensions 18a to 18f are not provided with an insulating film, and the suspension holder 17 and the bobbin suspension receiving portions 96 and 97 are made of a non-conductive material. The lens holder 16 is made of the above composite material. Therefore, since the member to which the suspensions 18a to 18f themselves are attached has insulating properties, the suspension itself does not need to be insulated. The bobbin suspension receivers 96 and 97 and the lens holder 16 are integrally formed by two-color molding, or the bobbin suspension receivers 96 and 97 and the lens holder 16 are joined by a resin adhesive. In this embodiment, the highly rigid lens holder 16 can be used without subjecting the suspensions 18a to 18f to an insulation treatment or the like.

  Next, the configuration of the lens holder 16 and the objective lens 10 of the optical pickup device according to another embodiment of the present invention will be described in more detail with reference to FIGS. The members shown in FIGS. 31 to 35 are slightly different from the members shown in FIGS. 6, 7, and 25 to 28, but the members having the same reference numerals have substantially the same functions. have.

  FIG. 31 shows the temperature distribution on the lens holder 16 when a current is passed through the focus coils 33 and 34, tracking coils 35 and 36, and sub-tracking coils 37 and 38. An objective lens 10 for a long wavelength laser and an objective lens 13 for a short wavelength laser are mounted on the lens holder 16. The objective lenses 10 and 13, the focus coils 33 and 34, the tracking coils 35 and 36, and the sub-tracking coils 37 and 38 shown in FIG. The heat generated by passing an electric current through the coil moves to the lens holder 16 and further moves to the objective lenses 10 and 13. The objective lenses 10 and 13 are deformed by the application of heat. This deformation is generally expansion, but may be contracted depending on the material. In general, a resin is deformed more greatly than heat when heated. Further, as can be seen from FIG. 31, the temperature distribution of the lens holder 16 is biased, and for the objective lens 10, the set side of the focus coil 33 and the sub-tracking coil 37 is heated more than the tracking coil 35 side. In other words, the set side of the focus coil 34 and the sub-tracking coil 38 is heated more than the tracking coil 36 side. Due to the deviation of the inflowing heat, the lens is also deformed, and aberration is generated in the light passing through the objective lenses 10 and 13.

  In FIG. 32, 110a, 110b, and 110c are objective lens support surfaces, and 111a, 111b, 111c, 113a, 113b, and 113c are adhesive portions. As described with reference to FIG. 7, the short-wavelength laser objective lens 13 is dropped into the through-hole 16b of the lens holder 16 from the P1 direction shown in FIG. 7, and is fixed with a photocurable adhesive or the like. Further, the objective lens 10 for the long wavelength laser is also dropped into the through hole 16a of the lens holder 16 from the P1 direction shown in FIG. 7, and is fixed with a photocurable adhesive or the like. Of the objective lenses 10 and 13 attached to the lens holder 16 in this way, the objective lens 10 is made of glass or resin, but here, one made of resin is used. This makes it possible to use a technique such as mold molding, so that it is easy to provide a hologram in the objective lens 10 and it is possible to adjust the spherical aberration of light of a plurality of types of wavelengths. The objective lens 13 is made of glass or made of a resin (preferably, a short wavelength light resin). Here, a glass made of glass is used. Thereby, the objective lens 13 is not easily deteriorated even with respect to light having a short wavelength, and good optical characteristics can be maintained. In the present embodiment, the objective lenses 10 and 13 are used. However, it is also possible to configure the lens with other condensing members such as a hologram.

  As described with reference to FIG. 6, the focus coils 33 and 34 are wound in a substantially ring shape, and are provided at diagonal positions of the lens holder 16, respectively. Since the focus coils 33 and 34 are provided on both sides of the lens holder 16 as described above, the optical pickup device can be made compact even if two lenses, the objective lens 10 and the objective lens 13, are mounted on the lens holder 16. It becomes possible to do. Similarly to the focus coils 33 and 34, the tracking coils 35 and 36 are wound in a substantially ring shape, and are provided at diagonal positions different from the focus coils 33 and 34, respectively. Sub-tracking coils 37 and 38 are provided between the focus coils 33 and 34 and the lens holder 16, respectively. By providing the sub-tracking coils 37 and 38, an unnecessary inclination of the lens holder 16 generated during tracking can be suppressed.

  The relationship between the objective lenses 10 and 13 and the lens holder 16 will be described in more detail with reference to FIG. The objective lens 13 is dropped into the through hole 16b formed in a substantially circular shape from the front of the paper to the back, and is fixed to the lens holder 16 with a photo-curable adhesive or the like injected into the bonding portions 113a, 113b, and 113c. The On the other hand, the objective lens 10 is dropped into a substantially circular through-hole 16a from the front to the back of the paper and is supported by the objective lens support surfaces 110a, 110b, and 110c, and is adjusted and bonded. The lens holder 16 is fixed with a photo-curing adhesive or the like injected into the portions 111a, 111b, and 111c. This configuration makes it possible to obtain optimal optical characteristics. Here, as the adhesive, a photocurable adhesive such as an ultraviolet curable adhesive that cures when irradiated with ultraviolet rays is used, but an instantaneous adhesive or other adhesives can also be used. Further, it is conceivable to use an adhesive having a low thermal conductivity, more preferably an adhesive having a heat insulating property that does not conduct heat.

  FIG. 33 shows a state where the objective lens 13 is dropped into the through hole 16b and the objective lens 10 is dropped into the through hole 16a. As described with reference to FIG. 7, the outer peripheral portions of the objective lenses 10 and 13 come into contact with the peripheral portions of the through holes 16 a and 16 b of the lens holder 16. The outer peripheral part of the objective lens 10 is in contact with the peripheral part of the through hole 16b of the lens holder 16 over almost the entire periphery. The contact of the objective lens 10 made of resin with the lens holder 16 will be described in more detail.

  34 is a cross-sectional view taken along line AA in FIG. 33, and FIG. 35 is a cross-sectional view taken along line BB in FIG.

  Reference numeral 10 a denotes an objective lens outer peripheral portion that becomes an edge of the objective lens 10, and the objective lens 10 is in contact with the lens holder 16 at a part of the objective lens outer peripheral portion 10 a and is bonded to the lens holder 16. In this way, the lens holder 16 and the objective lens 10 are fixed. Reference numeral 10b denotes an objective lens lower surface on which light emitted from the long wavelength optical unit 3 enters the objective lens 10, and 10c denotes an objective lens upper surface from which light incident on the objective lens 10 from the objective lens lower surface 10b is emitted. The light passing through the objective lens 10 and emitted from the objective lens upper surface 10c is condensed on the optical disc 2 facing the objective lens upper surface 10c. A hologram is provided on the lower surface 10b of the objective lens, and is emitted from the long wavelength optical unit 3 and passes through an optical member such as the relay lens 6 and the collimator lens 8 to become a parallel light beam (wavelength of about 660 nm (red). : For example, for DVDs and light beams of approximately 780 nm (infrared: for example for CDs), spherical aberration is adjusted by passing through this hologram.

  Reference numeral 110 denotes an objective lens support surface provided on the lens holder 16. 34 is a cross-sectional view taken along the line AA of FIG. 33, the objective lens support surface 110 is precisely the objective lens support surface 110c, but the objective lens support surfaces 110a, 110b, and 110c are substantially the same. Therefore, the objective lens support surfaces 110a, 110b, and 110c are collectively referred to as the objective lens support surface 110 for the sake of simplicity. The objective lens support surface 110 has an inclined surface from the lens holder upper surface 16c of the lens holder 16 toward the through hole 16a. More precisely, the inclined surface is a substantially spherical surface having a concave shape with respect to the lens holder upper surface 16c. When the objective lens 10 is placed on the objective lens support surface 110, the principal point of the objective lens 10 and the center of the substantially spherical surface of the objective lens support surface 110 preferably coincide with each other. The principal point of the objective lens 10 and the center of the substantially spherical surface of the objective lens support surface 110 may be slightly deviated, but a certain degree of deviation is allowed. By providing a substantially spherical surface on the objective lens support surface 110, the objective lens 10 is provided, and the direction of the optical axis of the objective lens 10 can be adjusted.

  Reference numeral 111 denotes an adhesive portion provided on the lens holder 16. 35 is a BB cross section of FIG. 33, the bonding portion 111 is precisely the bonding portion 111b. However, the bonding portions 111a, 111b, and 111c have substantially the same configuration and function. Therefore, for the sake of simplicity, the bonding portions 111a, 111b, and 111c are collectively referred to as the bonding portion 111 here. The adhesion portion 111 is a stepped portion that is lowered to the through hole 16 a side from the lens holder upper surface 16 c of the lens holder 16. The adhesion part 111 is configured so that the objective lens 10 does not hit when the objective lens 10 is slid on the objective lens support surface 110 and adjustment is performed.

  The arrangement of the objective lens support surface 110 and the bonding portion 111 will be described. As shown in FIG. 32, when the peripheral edge of the through hole 16a is viewed from the central axis of the through hole 16a, the angles that the objective lens support surfaces 110a, 110b, 110c occupy in the peripheral edge of the through hole 16a are all about 15 degrees. The angle occupied by the bonding portions 111a, 111b, and 111c in the peripheral portion of the through hole 16a is about 25 degrees. Since the contact portion between the lens holder 16 and the objective lens 10, which is the objective lens support surface 110 and the bonding portion 111, is configured to be small, the heat flow path from the lens holder 16 to the objective lens 10 is reduced, and the objective lens 10 An increase in temperature can be suppressed, and the deformation of the objective lens 10 can be reduced.

  The adhesive portion 111a is disposed at a position that avoids the vicinity of the set of the focus coil 33 and the sub-tracking coil 37 and does not approach the tracking coil 35 too much. In other words, the bonding portion 111 a is disposed at a position closer to the tracking coil 35 than the set of the focus coil 33 and the sub-tracking coil 37. With such a configuration, when the lens holder 16 is driven by passing a current through the focus coils 33 and 34, the tracking coils 35 and 36, and the sub-tracking coils 37 and 38, the focus coil 33 and the sub-tracking coil that are likely to rise in temperature. Between the pair of 37 and the tracking coil 35 whose temperature rise is smaller than that, the bonding portion 111a can be disposed at a low temperature position. The adhesion portions 111b and 111c are arranged at a position where the temperature of the adhesion portion 111a on the lens holder 16 is substantially equal. Here, the temperature difference between the bonding portions 111a, 111b, and 111c is preferably within 1 to 2 degrees. Since the sizes of the bonding portions 111a, 111b, and 111c are substantially equal, the adhesive injected into each bonding portion 111 comes into contact with the objective lens 10 with approximately the same area. As a result, the amount of heat flowing into the objective lens 10 from the bonding portions 111a, 111b, and 111c provided at positions where the temperatures are substantially equal is also substantially constant, and the deformation of the objective lens 10 is less likely to be biased. Generation of astigmatism of the passing light can be suppressed. Furthermore, the bonding portions 111a, 111b, and 111c are arranged at substantially equal angles around the central axis of the through hole 16a so as to be close to the intervals of 120 degrees. Preferably, the bonding portions 111 are arranged at equal intervals (equal angles) every 120 degrees, but are arranged so that the intervals are as close as possible around the through holes 16a at positions where the temperatures during driving are substantially equal. As a result, even if the adhesive injected into the bonding portion 111 is contracted when solidified, the force with which the objective lens 10 is pulled from the lens holder 16 cancels each other, and the positioned objective lens 10 is less likely to be displaced.

  In the present embodiment, the number of bonding portions 111 is three, but the number of bonding portions 111 is not limited to this. When the number of the bonding parts 111 is two, the arrangement of the bonding parts 111 is 180 degrees around the central axis of the through hole 16a, and when the number of the bonding parts 111 is four, Even when the number of the adhesive portions 111 is changed such that the arrangement is 90 degrees apart around the central axis of the through hole 16a, the arrangement of the adhesive portions 111 is preferably equiangular around the central axis of the through hole 16a. However, if the number of the bonding portions 111 is reduced, the force for fixing the objective lens 10 to the lens holder 16 is weakened or the bonding portions 111 need to be widened to prevent it. If the number of bonding portions 111 is increased too much, each bonding portion 111 can be made small, but a large number of positions on the lens holder 16 where the temperatures are almost equal are required, and the number of locations where the adhesive should be injected increases, resulting in an increase in the number of assembly steps. It will increase. It is preferable that the bonding portion 111 is composed of about three.

  Further, in the present embodiment, the adhesive portions 111a, 111b, and 111c are configured to have substantially the same area and are disposed at positions near the temperature on the lens holder 16. The amount of heat flowing from each bonding portion 111 can be made constant by changing the area of the bonding portion 111, for example, the bonding portion 111 is small and the bonding portion 111 provided at a low temperature is made large. It can be implemented similarly.

  The objective lens support surfaces 110a and 110b are adjacent to the bonding portions 111a and 111b, respectively, and are provided at positions closer to the set of the focus coil 33 and the sub-tracking coil 37 than the bonding portions 111a and 111b. The objective lens support surface 110c is adjacent to the bonding portion 111c and is provided at a position closer to the tracking coil 35 than the bonding portion 111c. As described above, by providing the objective lens support surface 110 adjacent to the bonding portion 111, the lens holder 16 is disposed at a low temperature, and heat conduction to the objective lens 10 can be suppressed. . Further, by providing the objective lens support surface 110 adjacent to the bonding portion 111, the objective lens support surface 110 can also be arranged at a substantially equiangular interval around the central axis of the through hole 16a. The objective lens 10 can be stably supported by the lens support surface 110.

  Further, in the present embodiment, the objective lens support surface 110 that is a member that supports the objective lens 10 is composed of three objective lens support surfaces 110a, 110b, and 110c. With this configuration, the lens holder 16 comes into contact with the objective lens outer peripheral portion 10a at three points, and the surface on which the objective lens 10 is supported can be uniquely determined. In the present embodiment, the number of points is three, but the number of points that support the objective lens 10 is not limited to this.

  In the present embodiment, the objective lens support surface 110 and the adhesive portion 111 are provided on the lens holder 16 as different surfaces. With this configuration, it is possible to prevent the adhesive from adhering to the objective lens support surface 110 for tilt adjustment, and it is possible to adjust the objective lens 10 with high accuracy. Further, by providing the bonding portion 111 separately from the objective lens support surface 110 and bonding the objective lens 10 and the lens holder 16, the objective lens 10 and the lens holder 16 can be firmly fixed.

  The objective lens support surfaces 110a and 110b are closer to the set of the focus coil 33 and the sub-tracking coil 37 than the adhesive portions 111a and 111b, respectively, and the objective lens support surface 110c is closer to the tracking coil 35 than the adhesive portion 111c. However, the objective lens 10 and the lens holder 16 are only in contact with each other on the objective lens support surface 110, and the adhesive portion 111 that easily conducts heat can be disposed at a position away from the high temperature portion. Thus, the temperature increase of 10 can be suppressed. Also in this embodiment, as described with reference to FIGS. 25 to 30, it is preferable that all or at least a part of the lens holder 16 is made of a material (composite material) in which fibers are dispersed in a resin. As the resin, liquid crystal polymer, epoxy resin, polyimide resin, polyamide resin, acrylic resin, etc. are suitably used, and as the fiber, metal fiber such as carbon fiber, carbon black, copper, nickel, aluminum, stainless steel, etc. In addition, these composite fibers are preferably used. As described above, when the lens holder 16 is made of the composite material, the lens holder 16 may have conductivity, but the rigidity of the lens holder 16 is increased and the resonance frequency is increased. It is possible to perform at least one of recording / reproduction in In the present embodiment, the lens holder 16 is made of a material in which carbon fibers are dispersed in a liquid crystal polymer. According to this configuration, the thermal conductivity of the lens holder 16 may be increased. When the thermal conductivity increases, the temperature of the lens holder 16 tends to be uniform, and the position of the bonding portion 111 can be selected from a wide range. When the thermal conductivity increases, the position of the bonding portion 111 can be selected from a wide range. , At an interval of approximately 120 degrees).

  The optical pickup device and the optical disc device of the present invention have the effect of suppressing the occurrence of aberration due to the deformation of the objective lens when the temperature distribution of the lens holder is biased, and realizing a reduction in size. It can be applied to such portable electronic devices and electronic devices such as stationary personal computers.

1 is a schematic diagram showing an optical pickup device according to an embodiment of the present invention. The figure which shows the optical pick-up apparatus in one embodiment of this invention The figure which shows the module which mounts the optical pick-up apparatus in one embodiment of this invention The figure which shows the module which mounts the optical pick-up apparatus in one embodiment of this invention The figure which shows a part of optical pick-up apparatus in one embodiment of this invention The figure which shows a part of optical pick-up apparatus in one embodiment of this invention The figure which shows a part of optical pick-up apparatus in one embodiment of this invention The figure which shows a part of optical pick-up apparatus in one embodiment of this invention The figure which shows a part of optical pick-up apparatus in one embodiment of this invention The figure which shows a part of optical pick-up apparatus in one embodiment of this invention The figure which shows a part of optical pick-up apparatus in one embodiment of this invention The figure which shows a part of optical pick-up apparatus in one embodiment of this invention The figure which shows a part of optical pick-up apparatus in one embodiment of this invention The figure which shows the light radiate | emitted from the light source of the optical pick-up apparatus in one embodiment of this invention The figure which shows the light radiate | emitted from the light source of the optical pick-up apparatus in one embodiment of this invention The figure which shows a part of optical pick-up apparatus in one embodiment of this invention The figure which shows a part of optical pick-up apparatus in one embodiment of this invention The figure which shows a part of optical pick-up apparatus in one embodiment of this invention The figure which shows a part of optical pick-up apparatus in one embodiment of this invention The figure which shows a part of optical pick-up apparatus in one embodiment of this invention The figure which shows a part of optical pick-up apparatus in one embodiment of this invention The figure which shows a part of optical pick-up apparatus in one embodiment of this invention The figure which shows a part of optical pick-up apparatus in one embodiment of this invention The figure which shows a part of optical pick-up apparatus in one embodiment of this invention The figure which shows a part of optical pick-up apparatus in other embodiment of this invention. The figure which shows a part of optical pick-up apparatus in other embodiment of this invention. The figure which shows a part of optical pick-up apparatus in other embodiment of this invention. The figure which shows a part of optical pick-up apparatus in other embodiment of this invention. The figure which shows a part of optical pick-up apparatus in other embodiment of this invention. The figure which shows a part of optical pick-up apparatus in other embodiment of this invention. The figure which shows the temperature distribution of the optical pick-up apparatus in other embodiment of this invention. The figure which shows a part of optical pick-up apparatus in other embodiment of this invention. The figure which shows a part of optical pick-up apparatus in other embodiment of this invention. The figure which shows a part of optical pick-up apparatus in other embodiment of this invention. The figure which shows a part of optical pick-up apparatus in other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Short wavelength optical unit 3 Long wavelength optical unit 7 Beam splitter 8a Support member 8c Lead screw 8d Gear group 8e Drive member 9,12 Rising mirror 10,13 Objective lens 21,22 Shaft 23 Screw shaft

Claims (25)

A light source;
A condensing member that condenses light from the light source;
Having a condensing member and a holder with a plurality of coils attached thereto;
The holder has a plurality of fixing portions for fixing the light collecting member,
An optical pickup device having a pair of focus coils of the coils on both sides of the holder. The optical pickup device according to claim 1, wherein the fixing portion is disposed at a position where the temperature when the holder is driven is substantially equal. The optical pickup device according to claim 1, wherein the fixing portion is disposed at a position where a temperature difference during driving of the holder is within 2 degrees. The optical pickup device according to claim 1, wherein the fixing portion is disposed at a substantially equal angle around a through hole to which the light collecting member is attached. The optical pickup device according to claim 1, wherein the fixing unit includes three fixing parts. 2. The optical pickup device according to claim 1, wherein the optical pickup device has three fixing portions and is arranged approximately every 120 degrees around a through hole to which the light collecting member is attached. The optical pickup device according to claim 1, wherein the fixing unit fixes the light collecting member and the holder with an adhesive. The optical pickup device according to claim 1, wherein the light collecting member is made of resin. The optical pickup device according to claim 1, wherein the light collecting member is a lens. The light source includes a first light source that emits light having a short wavelength, and a second light source that emits light having a longer wavelength than the first light source,
The condensing member includes a short wavelength condensing member that condenses the light emitted from the first light source, and a long wavelength condensing member that condenses the light emitted from the second light source. The optical pickup device according to claim 1, wherein the optical pickup device is provided. The optical pickup device according to claim 10, wherein the long wavelength condensing member is made of resin. The optical pickup device according to claim 10, wherein the short wavelength condensing member is made of glass. The optical pickup device according to claim 1, wherein the holder further includes a light collecting member support portion that supports the light collecting member. The optical pickup device according to claim 13, wherein the light collecting member support portion has a slope with respect to the holder. The optical pickup device according to claim 13, wherein the light collecting member support portion has a substantially spherical surface that is concave with respect to the upper surface of the holder. The optical pickup device according to claim 13, wherein the light collecting member support portion is disposed at a substantially equal angle around a through hole to which the light collecting member is attached. The optical pickup device according to claim 13, comprising three light collecting member support portions. 14. The optical pickup device according to claim 13, wherein the optical pickup device has three light collecting member support portions and is arranged approximately every 120 degrees around a through hole to which the light collecting member is attached. The optical pickup device according to claim 13, wherein the condensing member support portion is adjacent to the fixing portion. The holder has each of a pair of focus coils of the coils at diagonal positions of the holder,
2. The optical pickup device according to claim 1, wherein each of the pair of tracking coils is provided at another diagonal position of the holder. A first light source that emits light of a short wavelength;
A second light source that emits light having a longer wavelength than the first light source;
A short wavelength condensing member that condenses the light from the first light source;
A long wavelength condensing member that condenses light from the second light source;
A holder having the short wavelength condensing member and the long wavelength condensing member attached thereto;
The optical pickup device, wherein the holder has a plurality of fixing portions for fixing at least the long wavelength condensing member. The optical pickup device according to claim 21, wherein the long wavelength condensing member is made of resin. The holder further comprises a plurality of coils,
Each of the pair of focus coils of the coils has a diagonal position of the holder,
The optical pickup device according to claim 21, wherein each of the pair of tracking coils is provided at another diagonal position of the holder. The optical pickup device according to any one of claims 1 to 23, wherein the holder has conductivity. An optical pickup device according to any one of claims 1 to 24,
A base for movably holding the optical pickup device;
An optical disk apparatus comprising: a rotation driving means provided on the base for rotating the medium.

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