JP2007265559A - Optical pickup device and optical disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin type optical pickup device and an optical disk device in which the distance between a rise prism and an objective lens is minimized while sufficient recording and reproducing performance is secured. <P>SOLUTION: The optical pickup device 20 is provided with a laser light source 1 emitting light of two kind of waveforms, a diffraction element 2 provided with a first diffraction grating 2a generating light used for tracking control by transmitting light of one side emitted from the laser light source 1 and diffracting light of the other side and a second diffraction grating 2b generating light used for tracking control by transmitting light of the other side and diffracting light of one side, a light receiver 11 receiving light reflected by the optical disk, a beam splitter 3 forwarding the light reflected by the optical disk to the light receiver 11, and a detecting lens 10 provided between the beam splitter 3 and the light receiver 11 and generating light used for focus tracking by making focal distances different in two orthogonal cross sections including an optical axis. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical pickup device and an optical disk device mounted on an electronic device such as a personal computer or a notebook computer.

  2. Description of the Related Art Conventionally, as a notebook computer or the like equipped with an optical disk device becomes thinner, the optical disk device has also been made thinner. In order to reduce the thickness of the optical disk device, it is important to reduce the thickness of the optical pickup device, which is a basic component.

  FIG. 28 is a configuration diagram of an optical system of a conventional optical pickup device, FIG. 29A is a configuration diagram of a conventional optical pickup device, and FIG. 29B is a sectional view taken along line EE of FIG. The laser light source 101 emits a laser beam for DVD and a laser beam for CD. The diffraction element 102 includes a diffraction grating that transmits the laser beam for DVD as it is and diffracts and separates the laser beam for CD for tracking control. The integrated prism 103 has a plurality of inclined surfaces inside. DVD and CD laser light emitted from the laser light source 101 and reflected by the optical disk 111 toward the laser light source 101 is separated by a polarization separation film provided on the inclined surface so as to enter the light receiver 109. Further, the slope is provided with a CD hologram 103a, which separates the CD laser light into tracking control light and focus control light. The focus control light separated by the CD hologram 103a is further separated into light incident on the light receiver 109 before focusing on the light incident on the light receiver 109 after being focused.

  The collimating lens 104 is a lens that converts the DVD laser light and the CD laser light, which are divergent light emitted from the laser light source 101, into substantially parallel light. The reflection mirror 105 reflects the DVD and CD laser light emitted from the laser light source 101 to bend the optical path so as to reduce the size of the optical pickup device 100. Further, a part of the light is transmitted and incident on the second light receiver 110. The second light receiver 110 converts the amount of received laser light into an electrical signal. This electrical signal is used to control the amount of laser light emitted from the laser light source 101. The rising prism 106 is a prism that converts DVD and CD laser light emitted from the laser light source 101 substantially parallel to the optical disk 111 in a direction substantially perpendicular to the optical disk 111.

  The hologram element 107 is a combination of a DVD hologram 107a and a quarter-wave plate 107b. The DVD hologram 107a acts only on the DVD laser light reflected by the optical disc 111 according to the wavelength and polarization state of the incident laser light. The tracking control light and the focus control light are separated according to the position of the incident light on the DVD hologram 107a. The position of the spot on the recording track of the optical disc 111 corresponds to the position of the spot incident on the DVD hologram 107 a, and light in a region with a large amount of tracking information enters the light detection unit for tracking control of the light receiver 109. To do. The focus control light separated by the DVD hologram 107a is further separated into light incident on the light receiver 109 before focusing on the light incident on the light receiver 109 after focusing. The quarter wavelength plate 107 b converts the P-polarized laser light emitted from the laser light source 101 into circularly polarized light, and converts the circularly polarized laser light reflected by the optical disk 111 into S-polarized light. The objective lens 108 is a lens for condensing the DVD and CD laser light emitted from the laser light source 101 so as to be focused on the recording track of the optical disk 111. The optical disk 101 is a DVD or CD.

Each component on the optical path between the laser light source 101 including the laser light source 101 and the rising prism 106 is directly or otherwise placed on a base 121 which is a skeleton of the optical pickup device 100 as shown in FIG. It is fixed via the member. As shown in FIG. 29B, the objective lens 108 is fixed to the lens holder 123a together with the hologram element 107 directly above the hologram element 107. The lens holder 123 a is elastically supported by the main body of the objective lens driving device 123 so as to be movable in the tracking direction and the focusing direction of the optical disc 111, and the main body of the objective lens driving device 123 is fixed to the base 121. At this time, the objective lens 108 is disposed so as to be directly above the rising prism 106. Such a configuration is exemplified in, for example, (Patent Document 1), and an optical pickup device that can be mounted on an optical disc apparatus having a thickness of 9.5 mm corresponding to DVD and CD can be realized.
JP 2005-222636 A

  When the thickness of the optical disk device is further reduced to, for example, 7 mm, it is necessary to further reduce the distance from the lower end of the optical pickup device to the top of the objective lens, that is, the thickness of the optical pickup device. However, when trying to construct such a thin optical pickup device, it was necessary to reduce the distance between the starting prism and the objective lens, which originally had no room, and it was impossible to secure a space for placing the hologram element. . Therefore, a quarter-wave plate of the hologram element is disposed between the laser light source and the rising prism, but no particular problem has occurred. However, if the DVD hologram is arranged between the laser light source and the rising prism, the positional relationship between the DVD hologram and the objective lens slightly shifts, so that it is difficult to realize sufficient recording / reproducing performance for DVD and CD. became.

  The present invention solves the above-mentioned conventional problems, and ensures sufficient recording / reproduction performance for two types of optical disks corresponding to laser beams of different wavelengths, such as DVD and CD, while the riser prism and the objective lens. It is an object of the present invention to provide a thin optical pickup device and an optical disc device with a minimum distance.

  To achieve the above object, the present invention provides a laser light source that emits laser light of two types of wavelengths toward an optical disc, a laser light of one wavelength that is transmitted from the laser light source, and a laser of the other wavelength. The first diffraction grating for diffracting light to generate the laser light of the other wavelength used for tracking control and the laser light of the other wavelength are transmitted, and the laser light of the one wavelength is diffracted and used for tracking control. A diffraction element including a second diffraction grating that generates laser light of one wavelength, a light receiver that receives the laser light of the two types of wavelengths reflected by the optical disk, and the two types of light reflected by the optical disk A beam splitter for directing a laser beam of a wavelength to the light receiver, and a focal length at two cross sections provided between the beam splitter and the light receiver and including the optical axis. A detection lens for generating a laser beam of the two wavelengths used for different allowed by focus control, and an optical pickup apparatus comprising the.

  Laser light of two types of wavelengths used for tracking control by the diffractive element is generated. The detection lens generates laser light having two types of wavelengths used for focus control. Thereby, the function of generating the tracking control light and the function of generating the focus control light of the hologram can be assigned to the diffraction element and the detection lens, and the hologram can be omitted.

  The present invention makes it possible to minimize the distance between the start-up prism and the objective lens by omitting the hologram while ensuring sufficient recording / reproducing performance for two types of optical disks corresponding to laser beams of different wavelengths such as DVD and CD. Therefore, a thin optical pickup device and optical disc device can be realized.

  According to the first aspect of the present invention, a laser light source that emits laser light of two types of wavelengths toward an optical disk, a laser light of one wavelength emitted from the laser light source, and a laser light of the other wavelength are transmitted. A first diffraction grating that diffracts and generates a laser beam of the other wavelength used for tracking control and a laser beam of one wavelength that passes through the laser beam of the other wavelength and diffracts the laser beam of one wavelength and is used for tracking control A diffraction element having a second diffraction grating that generates a laser beam, a light receiver that receives laser light of two types of wavelengths reflected by the optical disc, and a laser beam of two types of wavelengths that is reflected by the optical disc. A beam splitter to be directed, and two wavelength arrays used for focus control with different focal lengths in two orthogonal sections including the optical axis provided between the beam splitter and the light receiver. A detecting lens which generates light, an optical pickup device provided with a.

  Laser light of two types of wavelengths used for tracking control by the diffractive element is generated. The detection lens generates laser light having two types of wavelengths used for focus control. Thereby, the function of generating the tracking control light and the function of generating the focus control light of the hologram can be assigned to the diffraction element and the detection lens, and the hologram can be omitted. Therefore, the hologram can be omitted and the distance between the start-up prism and the objective lens can be minimized while ensuring sufficient recording / reproducing performance for two types of optical disks corresponding to laser beams of different wavelengths such as DVD and CD. Therefore, a thin optical pickup device can be realized.

  According to a second aspect of the present invention, in the first aspect of the invention, the optical pickup includes a coupling member that holds the laser light source, the diffraction element, the light receiver, the beam splitter, and the detection lens as an integral unit and is fixed to the base. Device.

  The coupling member is not easily deformed by stresses such as temperature and changes with time. For this reason, positional deviation and angular deviation between the optical components held by the coupling member hardly occur. Therefore, stable and high-quality recording / reproducing characteristics can be obtained.

  According to a third aspect of the present invention, in the second aspect of the present invention, the laser light source is a light emitting element that emits laser light of one wavelength and a light emitting element that emits laser light of the other wavelength, or laser light of two types of wavelengths. The optical pickup device includes a plate for fixing a submount for fixing any one of the light emitting elements that emit light, and the plate is fixed to the coupling member.

  The thickness of the laser light source is the sum of the thickness of the light emitting element, the submount, and the plate plus the necessary thickness for the wiring, and can be reduced. Therefore, the thickness of the optical pickup device can be reduced. In addition, since a plate having a large area is fixed to the coupling member, good and stable assembly accuracy can be realized.

  A fourth aspect of the present invention is the optical pickup device according to the third aspect of the present invention, further comprising a heat dissipating member that connects the plate and the base.

  Since the heat generated by the laser light source and transmitted to the plate can be released from the base via the heat radiating member, more heat can be released than when the heat is released only from the coupling member. For this reason, the laser light source can be more stably operated with less temperature rise.

  The invention of claim 5 is the optical pickup device according to claim 4, wherein the heat dissipating member is a graphite sheet.

  The graphite sheet has high thermal conductivity and can transfer more heat to the base. For this reason, the laser light source can be more stably operated with less temperature rise.

  A sixth aspect of the present invention is the optical pickup device according to the first aspect of the present invention, wherein the two types of laser beams are a DVD laser beam and a CD laser beam.

  Laser light for DVD and CD used for tracking control by the diffraction element is generated. In addition, laser beams for DVD and CD used for focus control are generated by the detection lens. Thereby, the function of generating the tracking control light and the function of generating the focus control light of the hologram can be assigned to the diffraction element and the detection lens, and the hologram can be omitted. Accordingly, the hologram can be omitted and the distance between the start-up prism and the objective lens can be minimized while ensuring sufficient recording and reproducing performance for DVD and CD optical disks. Therefore, a thin optical pickup device and optical disc device can be realized.

  According to a seventh aspect of the present invention, in the first aspect of the invention, the first diffraction grating is the same as the first member having a predetermined refractive index and the first member having a predetermined refractive index for laser light of one wavelength. And a second member having a refractive index different from that of the first member having a predetermined refractive index for the laser light of the other wavelength. The second diffraction grating has a predetermined refractive index. The third member having the same refractive index as that of the third member having a predetermined refractive index for the laser light having one wavelength and the third member having the predetermined refractive index for the laser light having the other wavelength. A first member and a second member, which are alternately arranged in the plane of incidence of the two types of wavelengths of laser light to form a diffraction grating, and a third member; The fourth member is alternately arranged in the incident surface of the laser light of two types of wavelengths to form a diffraction grating, and the second member and the fourth member Wood are each optical pickup device to form a refractive index with the second member and the fourth member in that it contains organic matter having a light absorption in a predetermined wavelength range.

  The light quantity ratio of the laser beam having the other wavelength diffracted and separated by the first diffraction grating and the light quantity ratio of the laser light having the one wavelength diffracted and separated by the second diffraction grating can be freely set. Therefore, the design freedom of tracking control is improved for both types of laser beams having different wavelengths.

  The invention of claim 8 is the optical pickup device according to claim 7, wherein the organic substances contained in the second member and the fourth member are dyes.

  The dye is soluble in the solvent at the molecular level. Therefore, the rate at which the light incident on the second member and the fourth member is dispersed and lost is very small, and the transmittance can be kept high. Therefore, the ratio of the light reaching the optical disk is large, the laser light source can be driven with a small output, and the load on the laser light source can be reduced.

  A ninth aspect of the invention is the first aspect of the invention according to the seventh aspect, further comprising a first transparent substrate on which the first member is disposed and a second transparent substrate on which the third member is disposed, and the first member facing the first transparent substrate is disposed. The fourth member is an optical pickup device that is disposed by filling the same second member as the fourth member between the surface of the transparent substrate and the surface of the second transparent substrate on which the third member is disposed.

  This is the minimum necessary configuration and can be reduced in size. In addition, since the amount of materials is small and the number of manufacturing steps is small, it is easy to manufacture and can be inexpensive.

  A tenth aspect of the invention is the first aspect of the invention according to the seventh aspect, further comprising a first transparent substrate on which the second member is disposed and a second transparent substrate on which the fourth member is disposed, and the second member facing the first transparent substrate is disposed. The third member is an optical pickup device that is disposed by filling the same first member as the third member between the surface of the transparent substrate and the surface of the second transparent substrate on which the fourth member is disposed.

  This is the minimum necessary configuration and can be reduced in size. In addition, since the amount of materials is small and the number of manufacturing steps is small, it is easy to manufacture and can be inexpensive.

  The invention of claim 11 is the invention of claim 7, comprising a first transparent substrate, a second transparent substrate, and a third transparent substrate, wherein the first diffraction grating is provided on one surface of the first transparent substrate and the second transparent substrate. And the second diffraction grating is disposed in close contact with the other surface of the second transparent substrate and the third transparent substrate.

  It is relatively small and can be manufactured easily. In addition, each refractive index can be easily adjusted, and the configuration is easy to design.

  The invention of claim 12 is the invention of claim 7, comprising a first transparent substrate, a second transparent substrate, a third transparent substrate, and a fourth transparent substrate, and between the first transparent substrate and the second transparent substrate. The first diffraction grating is disposed in close contact, the second diffraction grating is disposed in close contact between the third transparent substrate and the fourth transparent substrate, and either the first transparent substrate or the second transparent substrate is disposed. This is an optical pickup device in which a surface on which one diffraction grating is not disposed and a surface on which any one of the third transparent substrate and the fourth substrate is not disposed are fixed.

  Since the first diffraction grating and the second diffraction grating can be separately manufactured, inspected, and only good products can be combined to manufacture a diffraction element, the yield can be increased.

  According to a thirteenth aspect of the present invention, in the first aspect of the invention, the light receiving device includes a light receiving element having a light detecting portion and a wiring board having a light transmitting portion facing the light detecting portion, and is reflected by an optical disc. The laser light of various types is an optical pickup device that enters the light detection section through the light transmission section.

  The light receiver is in a state where the light receiving element is not put in the package. A wiring substrate having a light transmission portion is disposed on the light detection surface side of the light receiving element. The size of the light receiver in the thickness direction of the optical pickup device can be reliably reduced as compared with the case where the light receiving element is accommodated in the package. Therefore, the thickness of the optical pickup device can be reduced.

  A fourteenth aspect of the invention is the optical pickup device according to the thirteenth aspect of the invention, wherein the light receiving element has electrodes connected to the wiring board arranged at the end, and the arrangement direction of the electrodes is a direction substantially perpendicular to the optical disk. .

  Since the wiring board necessary for connection need not be wired from the thickness direction of the optical pickup device, the thickness of the optical pickup device can be reduced.

  A fifteenth aspect of the invention comprises the second light receiver according to the first aspect of the invention, wherein the second light receiver receives light obtained by separating a part of the laser light having two types of wavelengths emitted from the laser light source from the light directed to the optical disk. The second light receiver is an optical pickup device that includes a light receiving element having a light detection unit, and a wiring substrate having a light transmission unit that transmits light separated from the light that faces the light detection unit and travels toward the optical disk.

  The second light receiver can generate a signal for controlling the output of the laser light source. The second light receiver is in a state where the light receiving element is not put in the package. A wiring substrate having a light transmission portion is disposed on the light detection surface side of the light receiving element. The size of the second light receiver in the thickness direction of the optical pickup device can be reliably reduced as compared with the case where the light receiving element is accommodated in the package. Therefore, the thickness of the optical pickup device can be reduced.

  A sixteenth aspect of the invention is the optical pickup device according to the fifteenth aspect of the invention, wherein the light receiving element is arranged with electrodes connected to the wiring board at the end, and the arrangement direction of the electrodes is a direction substantially perpendicular to the optical disk. .

  Since the wiring board necessary for connection need not be wired from the thickness direction of the optical pickup device, the thickness of the optical pickup device can be reduced.

  A seventeenth aspect of the present invention is the optical pickup apparatus according to the fifteenth aspect of the present invention, wherein the beam splitter separates a part of the laser light having two kinds of wavelengths emitted from the laser light source from the light directed to the optical disk.

  Since a new optical component having this function is not required by adding a function for separating a part of laser light of two kinds of wavelengths emitted from the laser light source to the light directed to the optical disk in the beam splitter, its spectral pickup The apparatus can be made small, light and inexpensive.

  An eighteenth aspect of the present invention is the optical pickup device according to the seventeenth aspect of the present invention, further comprising a light reducing member between the beam splitter and the second light receiver.

  When a part of laser light having two types of wavelengths emitted from the laser light source is separated from the light directed to the optical disk by the beam splitter, the amount of light directed to the second light receiver is too large. By providing the light reducing member, the amount of light incident on the second light receiver is optimized.

  A nineteenth aspect of the present invention is the optical pickup device according to the eighteenth aspect, wherein the light reducing member is a light absorption film formed on a surface of the beam splitter facing the second light receiver.

  Since the light absorption film is formed on the beam splitter, it is not necessary to provide a new component, and the optical pickup device can be made inexpensive and light.

  According to a twentieth aspect of the invention, in the fifteenth aspect of the invention, the second light receiver is fixed to a coupling member that holds the laser light source, the diffraction element, the light receiver, the beam splitter, and the detection lens as an integral unit. It is.

  Since the distance from the beam splitter can be shortened, all the light emitted from the beam splitter can be made incident before the light spreads, and the generation of stray light can be suppressed.

  A twenty-first aspect of the present invention is the optical pickup apparatus according to the fifteenth aspect of the present invention, further comprising a second beam splitter that separates part of the laser light having two types of wavelengths emitted from the laser light source from the light directed to the optical disk. .

  The second beam splitter can also serve as a reflection mirror that bends the optical path to reduce the size of the optical pickup device. Moreover, the light quantity which goes to a 2nd light receiver can be optimized. Therefore, since no new optical parts are required, the spectral pickup device can be made small, light, and inexpensive.

  According to a twenty-second aspect of the present invention, in the invention of the second aspect, the laser light having two types of wavelengths emitted from the laser light source having a flat surface on the side surface close to the optical disk and the side surface opposite to the side surface is substantially parallel light. A collimating lens and a fixing member for fixing the collimating lens, and the collimating lens is disposed on the base body side of the opening of the base so that the side surface including one of the planes faces the opening. An optical pickup device in which the central portion of the fixing member is fixed to a plane facing the opening from the other side of the portion, and the fixing member is warped on the collimating lens side.

  The collimating lens has a large diameter, and is flattened by dropping the side surface close to the optical disc and the side surface opposite to the side surface so that the collimating lens can be accommodated in the thickness direction of the optical pickup device. The collimating lens can be fixed to the base by the force of returning to the original shape of the fixing member by bending the fixing member to the collimating lens side and fixing it to the plane of the collimating lens across the opening of the base. it can. Further, the thickness required for fixing is minimal, and the thickness of the optical pickup device can be reduced.

  The invention of claim 23 is the invention of claim 22, wherein a groove is provided outside the opening of the base on the side where the fixing member is arranged, and there are two types of contact portions that contact the collimator lens of the base. This is an optical pickup device that is parallel to the optical axis of the laser beam having the wavelength and uses the groove as a guide at both ends of the fixed member.

  Collimating lenses require precise position adjustment in the optical axis direction during manufacturing. Since the collimating lens can be forcibly moved along the contact portion and the groove, the position in the optical axis direction can be adjusted without changing the attitude of the collimating lens.

  According to a twenty-fourth aspect of the present invention, in the first aspect of the present invention, there are provided two types of collimating lenses, which are arranged between the collimating lens and the optical disc. A triangular rising prism that converts the traveling direction of laser light of a wavelength into a direction perpendicular to the recording surface of the optical disc, and a surface that is disposed between the collimating lens and the rising prism and that faces the collimating lens An optical pickup device including a wedge-shaped prism that is closer to an optical disc and closer to a surface facing the prism.

  The distance between the optical disk and the objective lens cannot be made too small to prevent a collision. On the other hand, the laser beam emitted from the objective lens toward the optical disc must have a constant numerical aperture. For this reason, the diameter of the laser light emitted from the objective lens cannot be made too small. From the time when the laser light emitted from the laser light source is converted into substantially parallel light in the collimating lens to the time when it enters the rising prism, the dimension becomes rate-limiting at the same diameter as the laser light emitted from the objective lens, Further, the thickness of the optical pickup device cannot be reduced. Therefore, the laser beam from the collimating lens to the rising prism is required by expanding the width of the component in the thickness direction of the optical pickup device out of the light incident from the collimating lens by the rising prism and making it enter the objective lens. The width in the thickness direction of the optical pickup device can be reduced. For this purpose, a triangular rising prism is used. However, in order for the light emitted from the rising prism to be in a direction that is exactly perpendicular to the objective lens, the direction of the laser light incident on the rising prism is a direction having a component slightly perpendicular to the optical disk. There is a need to. Therefore, a wedge prism is disposed between the collimating lens and the rising prism so that the distance between the surface facing the collimating lens and the surface facing the rising prism is closer to the optical disc. That is, the traveling direction of the laser beam in the direction parallel to the optical disc has a slight component in the direction perpendicular to the optical disc. As a result, the diameter of the laser beam emitted from the objective lens can be secured, the collision between the optical disc and the optical pickup device can be suppressed, and a thin optical pickup device can be obtained.

  According to a twenty-fifth aspect of the present invention, in the invention of the twenty-fourth aspect, when the width in the direction perpendicular to the optical disk and perpendicular to the optical axis of the two kinds of laser beams incident on the rising prism is emitted from the rising prism, 1.10 It is an optical pickup device that is at least twice and at most 1.50 times.

  A collision between the optical disc and the optical pickup device can be suppressed, and a balance can be achieved with the thinning of the optical pickup device.

  The invention of claim 26 is directed to a laser light source that emits laser light of two types of wavelengths toward an optical disc and a laser beam of one wavelength that is emitted from the laser light source and diffracts the laser light of the other wavelength. A first diffraction grating that generates laser light of the other wavelength used for tracking control and the laser light of the other wavelength are transmitted, and the laser light of one wavelength is diffracted to generate laser light of one wavelength used for tracking control. A diffraction element having a second diffraction grating, a light receiver for receiving laser light of two types of wavelengths reflected by the optical disk, and a beam for directing laser light of two types of wavelengths reflected by the optical disk to the light receiver Two types of laser beams for use in focus control with different focal lengths in two cross sections that are provided between the splitter, the beam splitter, and the light receiver and that are orthogonal to each other including the optical axis. A detection lens for forming an optical disk apparatus characterized by comprising an optical pickup device provided with a.

  Laser light of two types of wavelengths used for tracking control by the diffractive element is generated. The detection lens generates laser light having two types of wavelengths used for focus control. Thereby, the function of generating the tracking control light and the function of generating the focus control light of the hologram can be assigned to the diffraction element and the detection lens, and the hologram can be omitted. Therefore, the hologram can be omitted and the distance between the start-up prism and the objective lens can be minimized while ensuring sufficient recording / reproducing performance for two types of optical disks corresponding to laser beams of different wavelengths such as DVD and CD. Therefore, a thin optical pickup device can be realized. Since such an optical pickup device is provided, a thin optical disc device can be realized while ensuring sufficient recording / reproducing performance for two types of optical discs corresponding to laser beams of different wavelengths such as DVD and CD. .

(Embodiment 1)
The first embodiment will be described with reference to the drawings. FIG. 1 is a configuration diagram of the optical pickup device of the first embodiment, and FIG. 2 is a configuration diagram of an optical system of the optical pickup device of the first embodiment. The optical pickup device 20 is configured by attaching various components directly or via other components to a base 15 that is a skeleton. The laser light source 1, the diffractive element 2, the beam splitter 3, the detection lens 10, and the light receiver 11 are held as a unit integrated with the coupling member 16 to constitute a laser module 17. The coupling member 16 of the laser module 17 is fixed to the base 15. The objective lens 9 is fixed to a lens holder 18 that forms a part of the objective lens driving device 19, and the lens holder 18 is elastically supported by the main body of the objective lens driving device 19. The main body of the objective lens driving device 19 is fixed to the base 15. Further, the reflection mirror 4, the quarter wavelength plate 6, the wedge prism 7, the rising prism 8, the dimming member 12, and the second light receiver 13 are directly fixed to the base 15. In FIG. 2, projection from the laser light source 1 to the quarter-wave plate 6 is performed on a plane parallel to the optical disk 14, and projection from the wedge prism 7 to the optical disk 14 is performed on a plane perpendicular to the optical disk 14. It is.

  FIG. 3 is a configuration diagram of the laser light source according to the first embodiment. The laser light source 1 was a so-called frame laser light source provided with a plate 1c for fixing a submount 1b for fixing the light emitting element 1a. The thickness of the laser light source 1 is the sum of the thicknesses of the light emitting element 1a, the submount 1b, and the plate 1c plus the necessary thickness for the wiring, and can be reduced. Therefore, the thickness of the optical pickup device 20 can be reduced. The light emitting element 1a is an element that emits a DVD laser beam having a wavelength of about 650 nm and a CD laser beam having a wavelength of about 780 nm. However, the light emitting element 1a may be two elements, that is, an element that emits a laser beam for DVD and an element that emits a laser beam for CD. Thus, the laser light source 1 emits laser light of two types of wavelengths for DVD and CD. In the first embodiment, laser light of two wavelengths is used for DVD and CD. For example, laser light having a wavelength of about 405 nm used for Blu-ray disc and HD DVD and laser light for DVD and CD are used. The generality is not lost even in combination.

  The submount 1b is formed of an insulating material having good thermal conductivity such as aluminum nitride. The plate 1c is composed of a plate-like body made of a metal material such as Cu, Cu alloy, Ag, Ag alloy, Al, Al alloy, Fe, or Fe alloy. More preferably, a material having good weldability is coated on the plate-like body by means such as plating or vapor deposition. The plate 1c may be made of a material having good thermal conductivity and high conductivity, such as conductive ceramics.

  The light emitting element 1a and the submount 1b are fixed with solder, and the submount 1b and the plate 1c are fixed with solder including cream solder, a conductive adhesive, or the like. A pattern is formed on the surface of the submount 1b and the plate 1c so that the light emitting element 1a and the lead 1d are appropriately connected, and wiring is performed by wire bonding using a gold wire. The wiring is protected by the protective member 1e. The plate 1c is fixed to the coupling member 16 at a plane portion outside the protective member 1e. Since the plate 1c is fixed to the coupling member 16 in a wide area, good and stable assembly accuracy can be realized. A current for driving the light emitting element 1a is supplied from the lead 1d. Further, the back side of the plate 1c is flat, and a graphite sheet as a heat radiating member is attached to this portion as will be described later.

  4A is a configuration diagram of the diffraction grating according to the first embodiment, FIG. 4B is a cross-sectional view taken along the plane A, FIG. 4C is a cross-sectional view taken along the plane B, and FIG. It is sectional drawing by. In the diffraction element 2, a first diffraction grating 2a is formed on a first transparent substrate 2g, a second diffraction grating 2b is formed on a second transparent substrate 2h, and the first diffraction grating 2a and the second diffraction grating 2b are opposed to each other. Then, the structure was bonded with the adhesive 2i. The first diffraction grating 2a is disposed on the laser light source side 1 side, and is a CD diffraction grating that transmits the laser beam for DVD as it is and diffracts and separates the laser beam for CD. The laser beam diffracted and separated by the first diffraction grating 2a is used for CD tracking control. The second diffraction grating 2b is disposed on the optical disk 14 side, and is a DVD diffraction grating that diffracts and separates the DVD laser light and transmits the CD laser light as it is. The laser beam diffracted and separated by the second diffraction grating 2b is used for DVD tracking control. In the configuration of FIG. 4, the first diffraction grating 2 a includes a first member 2 c that forms unevenness and a second member 2 d that fills the unevenness and flattens it. The second member 2d contains an organic substance (not shown) having light absorption in a predetermined wavelength range. The second diffraction grating 2b includes a third member 2e that forms unevenness and a fourth member 2f that fills the unevenness and flattens the surface. The fourth member 2f contains an organic substance (not shown) having light absorption in a predetermined wavelength range. The laser beam for CD is diffracted and separated by the unevenness of the first diffraction grating 2a, and is arranged on the optical disk 14 of the CD in a predetermined direction with a predetermined light intensity ratio at a predetermined interval. On the contrary, the height of the unevenness, the arrangement interval, and the direction are determined so as to be like that. The DVD laser light is diffracted and separated by the unevenness of the second diffraction grating 2b, and is arranged on the DVD optical disk 14 in a predetermined direction with a predetermined light intensity ratio at a predetermined interval. On the contrary, the height of the unevenness, the arrangement interval, and the direction are determined so as to be like that.

  FIG. 5A is a diagram illustrating the principle of the diffraction grating according to the first embodiment, and FIG. 5B is a diagram illustrating the relationship between the wavelength and the refractive index of each diffraction grating. In general, two objects having unevenness are in contact with each other, and when light passes through the unevenness, the light is diffracted if the refractive index of the two objects is different, but if the refractive index is equal, the light is transmitted as it is. As shown in FIG. 5 (a), when an organic substance having light absorption in a predetermined wavelength region is contained in a certain material, a region on the long wavelength side just outside the wavelength region having light absorption and a short wavelength side just outside The refractive index of the region is larger than the case where it does not contain. This phenomenon is called an anomalous dispersion phenomenon. Ordinary materials have a small wavelength dependency of the refractive index, but the wavelength dependency of the refractive index can be increased by utilizing this anomalous dispersion phenomenon. Therefore, it is possible to realize a configuration in which the refractive indexes of the two materials constituting the diffraction grating are equal at one wavelength and different at the other wavelength. As shown in FIG. 5B, in the first diffraction grating 2a, the wavelength dependency of the refractive index of the second member 2d containing the organic substance is large, and the refractive indexes of the first member 2c and the second member 2d are for DVD. The laser light wavelength is approximately equal to 650 nm, and the CD laser light wavelength is 780 nm, which is different. Further, in the second diffraction grating 2b, the wavelength dependency of the refractive index of the fourth member 2f containing the organic substance is large, and the refractive indexes of the third member 2e and the fourth member 2f are different at the wavelength of 650 nm and almost equal at the wavelength of 780 nm. It is trying to become. Laser light having a wavelength with the same refractive index is transmitted as it is regardless of the height of the irregularities of the diffraction grating. Therefore, the height of the unevenness of the diffraction grating can be designed so that the separated light has an optimum light quantity ratio with respect to the laser light having the wavelength to be diffracted. That is, the design freedom of tracking control is improved for both DVD and CD.

  Among these organic substances, those that absorb light in the visible light region and are colored are called dyes and pigments. There is a difference that a dye is dissolved in a solvent at a molecular level, and a pigment is not dissolved but floats in a fine particle state. In the case of a dye, the rate at which light is dispersed and lost by suspended fine particles such as pigment is very small, and the transmittance can be kept high. Therefore, the ratio of the light reaching the optical disk 14 is large, the laser light source 1 can be driven with a small output, and the load on the laser light source 1 can be reduced. On the other hand, the pigment has an advantage of less deterioration due to ultraviolet rays and the like, and the degree of freedom of the process of manufacturing the optical pickup device 20 as well as the process of manufacturing the diffraction element 2 itself can be increased.

  The base containing the organic material of the first member 2c and the second member 2d, and the base containing the organic material of the third member 2e and the fourth member 2f are made of Epo-Tek manufactured by Epoxy Technology, Inc., which is a transparent resin. Epoxy-based thermosetting adhesives such as 310, 320, and 330, acrylic UV-curable adhesives such as Epo-Tek's OG114, polyimide resins such as PIMEL7640 manufactured by Asahi Kasei Electronics Co., Ltd., AZ Electronic Materials ) There are resists such as AZ6130 made, and these are used in combination as appropriate. As an organic substance to be contained, red dyes such as red dye No. 102 and red No. 2 have almost no light absorption in the visible wavelength range, and copper chlorophyllin sodium, etc., which has most of the light absorption in the ultraviolet wavelength range. Examples thereof include NK-4432, NK-4489, and NK-2911 manufactured by Hayashibara Biochemical Laboratories Co., Ltd., which have light absorption in the wavelength range, and pigment red 254 and pigment red 177, which are red pigments. The first transparent substrate 2g and the second transparent substrate 2h are optical glass or optical plastic represented by BK7. The adhesive 2i is an ultraviolet curable adhesive, a thermosetting adhesive, an anaerobic adhesive, or the like, and transmits two types of laser light used, DVD laser light and CD laser light. It ’s fine.

  Examples of a method for manufacturing such a diffraction element 2 include the following methods. First, the material of the first member 2c is applied on the first transparent substrate 2g so as to be uniform at a predetermined thickness by a spin coating method, and is cured by heating and holding. Next, ultraviolet rays are irradiated and developed through a mask pattern that forms a predetermined pattern, thereby forming a predetermined uneven shape. The uneven step formed by the first member 2c is the height of the uneven portion of the first diffraction grating 2a. Here, final curing may be performed as necessary. The refractive index of the first member 2c can be adjusted by appropriately setting each curing condition. Next, the third member 2d containing an organic substance having light absorption in a predetermined wavelength region is filled in the concave and convex portions by a spin coating method or a screen printing method, and is flattened, and is heated and held to be cured. . In this way, the first diffraction grating 2a is formed on the first transparent substrate 2g. Similarly, the second diffraction grating 2b is formed on the second transparent substrate 2h. Next, the first diffraction grating 2a and the second diffraction grating 2b are bonded to the adhesive 2i so that the direction in which the irregularities of the first diffraction grating 2a are arranged and the direction in which the irregularities of the second diffraction grating 2b are arranged are a predetermined direction. Paste together. Finally, it is cut to a predetermined dimension and completed.

  The diffractive element 2 manufactured and configured by the method as described above has a light quantity ratio of CD laser light diffracted and separated by the first diffraction grating 2a and a DVD diffracted and separated by the second diffraction grating 2b. The light quantity ratio of the laser beam can be set freely. Therefore, the degree of freedom in designing tracking control is improved for both CD and DVD.

  In the first embodiment, the second member 2d and the fourth member 2f containing organic substances are used to fill the unevenness and flatten the surface, but the present invention is not limited to this. The second member 2d containing an organic substance having light absorption in a predetermined wavelength region may be used to form the unevenness, and the first member 2c may be used to fill the unevenness and make it flat. In addition, the fourth member 2f containing an organic substance having light absorption in a predetermined wavelength range may be used to form the unevenness, and the third member 2e may be used to fill the unevenness and make it flat.

  In the first embodiment, the diffraction element 2 is configured by forming a first diffraction grating 2a on a first transparent substrate 2g and a second diffraction grating 2b on a second transparent substrate 2h. Although 2a and the 2nd diffraction grating 2b were set as the structure adhere | attached with the adhesive agent 2i, it is not restricted to the structure.

  6A is a configuration diagram of another example 1 of the diffraction element according to the first embodiment, FIG. 6B is a diagram showing the relationship between the wavelength and refractive index of each diffraction grating, and FIG. FIG. 7B is a configuration diagram of another example 2 of the diffraction element according to the first embodiment, and FIG. 7B is a diagram illustrating the relationship between the wavelength and the refractive index of each diffraction grating.

  In FIG. 6A, the structure of the diffraction element 2 is such that the first member 2c forms irregularities on the first transparent substrate 2g, and the third member 2e forms irregularities on the second transparent substrate 2h. The fourth member is filled with the same second member 2d between the opposed first member 2c and third member 2e. The second member 2d contains an organic substance having light absorption in a predetermined wavelength range. The first diffraction grating 2a includes a first member 2c and a second member 2d. The second diffraction grating 2b includes a second member 2d and a third member 2e that are the same body as the fourth member. As shown in FIG. 6B, the refractive index of the second member 2d is equal to the refractive index of the first member 2c at a wavelength of 650 nm for DVD, and is equal to the refractive index of the third member 2e at a wavelength of 780 nm for CD. Thus, this configuration can be realized. In addition, such a combination of materials is selected.

  In order to manufacture such a diffractive element 2, as in the method described above, first, irregularities of a predetermined shape are formed on the first transparent substrate 2g by the first member 2c. Similarly, irregularities having a predetermined shape are formed on the second transparent substrate 2h by the third member 2e. Next, the 2nd member 2d containing the organic substance which has light absorption in a predetermined wavelength range is apply | coated on the 1st transparent substrate 2g in which the 1st member 2c was formed. On the second transparent substrate 2h, the direction of the unevenness of the first member 2c and the direction of the unevenness of the third member 2e are in a predetermined direction so that the third member 2e faces the first member 2c. And the second member 2d is cured by heating and holding. Finally, it is cut to a predetermined dimension and completed. The second member 2d may be applied on the second transparent substrate 2h on which the third member 2e is formed, and the first transparent substrate 2g may be overlaid.

  This is the minimum necessary configuration and can be reduced in size. In addition, since the amount of materials is small and the number of manufacturing steps is small, it is easy to manufacture and can be inexpensive.

  Further, in FIG. 7A, the configuration of the diffractive element 2 is opposite to the configuration of FIG. 6A, and includes a first material containing an organic substance having light absorption in a predetermined wavelength region on the first transparent substrate 2g. Concavities and convexities are formed by the two members 2d, and concavities and convexities are formed on the second transparent substrate 2h by the fourth member 2f containing an organic substance having light absorption in a predetermined wavelength range, and the second member 2d and the fourth member 2d are opposed to each other. The third member 2e is filled with the same first member 2c between the member 2f. It is not necessary for the first member 2c to contain an organic substance having light absorption in a predetermined wavelength range. The first diffraction grating 2a includes a first member 2c and a second member 2d. The second diffraction grating 2b includes a first member 2c and a fourth member 3f that are the same body as the third member 2e. As shown in FIG. 7B, the refractive index of the first member 2c is equal to the refractive index of the second member 2d at the wavelength of 650 nm for DVD, and is equal to the refractive index of the fourth member 3f at the wavelength of 780 nm for CD. Thus, this configuration can be realized. In addition, such a combination of materials is selected. It can be manufactured by a method substantially similar to that of the diffraction element having the configuration shown in FIG. Therefore, this configuration is also the minimum necessary configuration and can be reduced in size. In addition, since the amount of materials is small and the number of manufacturing steps is small, it is easy to manufacture and can be inexpensive.

  Moreover, it is good also as a structure as shown to Fig.8 (a) from FIG.8 (d).

  8A is a configuration diagram of another example 3 of the diffraction element according to the first embodiment, FIG. 8B is a configuration diagram of another example 4, and FIG. 8C is a configuration diagram of another example 5. FIG. 8D is a configuration diagram of another example 6. The configuration of FIG. 8A is as follows. A diffraction element in which the first diffraction grating 2a is disposed between the first transparent substrate 2g and the second transparent substrate 2h, and a second diffraction grating 2b is disposed between the third transparent substrate 2j and the fourth transparent substrate 2k. The diffraction element is bonded with an adhesive 2i. The first diffraction grating 2a includes a first member 2c and a second member 2d containing an organic substance having light absorption in a predetermined wavelength range. The second diffraction grating 2b includes a third member 2e and a fourth member 2f containing an organic substance having light absorption in a predetermined wavelength range.

  In order to obtain such a configuration, first, as in the above, irregularities having a predetermined shape are formed on the first transparent substrate 2g by the first member 2c. Next, the 2nd member 2d containing the organic substance which has light absorption in a predetermined wavelength range is apply | coated on the 1st transparent substrate 2g in which the 1st member 2c was formed. Next, the second transparent substrate 2h is overlaid, heated and held to cure the second member 2d, and a diffraction element provided with the first diffraction grating 2a is produced. Similarly, a diffraction element including the second diffraction grating 2b is manufactured. Next, both diffractive elements are bonded together with an adhesive 2i and cut into predetermined dimensions to complete. Since the first diffraction grating 2a and the second diffraction grating 2b can be manufactured separately and inspected to combine only good products, the diffraction element 2 can be manufactured, so that the yield can be increased.

  8B, 8C, and 8D, the first diffraction grating 2a is disposed between the first transparent substrate 2g and the second transparent substrate 2h, and the second transparent substrate 2h The second diffraction grating 2b is disposed between the third transparent substrate 2j. The first diffraction grating 2a includes a first member 2c and a second member 2d containing an organic substance having light absorption in a predetermined wavelength range. The second diffraction grating 2b includes a third member 2e and a fourth member 2f containing an organic substance having light absorption in a predetermined wavelength range.

  In order to obtain the configuration shown in FIG. 8B, first, as in the method described above, first, irregularities having a predetermined shape are formed on the first transparent substrate 2g by the first member 2c. Similarly, irregularities having a predetermined shape are formed on the third transparent substrate 2j by the third member 2e. Next, the 2nd member 2d containing the organic substance which has light absorption in a predetermined wavelength range is apply | coated on the 1st transparent substrate 2g in which the 1st member 2c was formed. Similarly, a fourth member 2f containing an organic substance having light absorption in a predetermined wavelength region is applied on the third transparent substrate 2j on which the third member 2e is formed. Next, the second transparent substrate 2h is overlaid on the first transparent substrate 2g coated with the second member 2d, and the third transparent substrate 2j coated with the fourth member 2f is turned over and overlaid. The second member 2d and the fourth member 2f are cured by heating and are cut into predetermined dimensions to be completed.

  In order to obtain the configuration shown in FIG. 8C, first, as in the method described above, irregularities having a predetermined shape are formed on the first transparent substrate 2g by the first member 2c. Next, the 2nd member 2d containing the organic substance which has light absorption in a predetermined wavelength range is apply | coated on the 1st transparent substrate 2g in which the 1st member 2c was formed. Next, the second transparent substrate 2h is stacked and heated and held to cure the second member 2d. Next, unevenness of a predetermined shape is formed by the third member 2e on the second transparent substrate 2h in the same manner as described above. Next, the 4th member 2f containing the organic substance which has light absorption in a predetermined wavelength range is apply | coated on the 2nd transparent substrate 2h in which the 3rd member 2e was formed. Next, the third transparent substrate 2j is stacked and heated and held to cure the fourth member 2f. Finally, it is cut into predetermined dimensions to complete.

  In order to obtain the configuration of FIG. 8D, first, similarly to the method described above, first, irregularities of a predetermined shape are formed on the second transparent substrate 2h by the first member 2c. Next, the second member 2d containing an organic substance having light absorption in a predetermined wavelength region is applied on the second transparent substrate 2h on which the first member 2c is formed. Next, the first transparent substrate 2g is stacked and heated and held to cure the second member 2d. Next, unevenness of a predetermined shape is formed by the third member 2e on the second transparent substrate 2h in the same manner as described above. Next, the 4th member 2f containing the organic substance which has light absorption in a predetermined wavelength range is apply | coated on the 2nd transparent substrate 2h in which the 3rd member 2e was formed. Next, the third transparent substrate 2j is stacked and heated and held to cure the fourth member 2f. Finally, it is cut into predetermined dimensions to complete. As described above, the configuration shown in FIGS. 8B, 8C, and 8D is relatively small and can be easily manufactured.

  The diffraction element 2 may have the following configuration. 9A is a configuration diagram of another example 7 of the diffraction element according to the first embodiment, FIG. 9B is a cross-sectional view taken along the plane A, FIG. 9C is a bottom view, and FIG. It is a top view. 10A is a configuration diagram of another example 8 of the diffraction element according to the first embodiment, FIG. 10B is a cross-sectional view taken along plane A, and FIG. 10C is a cross-sectional view taken along plane B. 10 (d) is a top view.

  The diffractive element 2 in FIG. 9 has a configuration in which a first diffraction grating 2a having an uneven surface on the lower surface side of the first transparent substrate 2g and a second diffraction grating 2b having an uneven surface on the upper surface side are provided. The light quantity ratio of the light diffracted and separated by the diffraction element 2 is such that the refractive index of the transparent substrate is n, the wavelength of the transmitted light is λ, and the height of the unevenness of the diffraction element 2 is d, the phase difference φ = (n− 1) It is determined by xd / λ. When φ is an even multiple of 1/2 (natural number), 100% is transmitted as it is, and the diffraction is 0%. When φ is an odd multiple of 1/2, the diffraction is 100%, and the transmittance is 0%. It becomes. Therefore, if φ is a natural number in order to transmit 100% of the laser beam for DVD through the first diffraction grating 2a, the height of the unevenness of the first diffraction grating 2a is inevitably determined, and is diffracted and separated accordingly. The light quantity ratio of the laser beam for CD is inevitably determined. The first diffraction grating 2a can be used when the light quantity ratio can be used for CD tracking control. The same applies to the second diffraction grating 2b for DVD. In the case of FIG. 9, since the unevenness is simply provided, the diffractive element 2 can be made cheaper than in the case of the configuration of FIGS.

  FIG. 10 shows a configuration in which the first diffraction grating 2a is provided between the first transparent substrate 2g and the second transparent substrate 2h, and the second diffraction grating 2b is provided on the surface of the second transparent substrate 2h. The first diffraction grating 2a includes a first member 2c and a second member 2d containing an organic substance having light absorption in a predetermined wavelength range. The second diffraction grating 2b is obtained by making the surface of the second transparent substrate 2h uneven. The first diffraction grating 2a and the second diffraction grating 2b may be reversed. For example, it can be used when the first diffraction grating 2a in the configuration of FIG. 9 cannot be used for CD tracking control. Again, the diffractive element 2 can be made cheaper than in the case of the configurations of FIGS. 4, 6, 7, and 8.

  In the first embodiment, the first diffraction grating 2a is arranged on the laser light source 1 side and the second diffraction grating 2b is arranged on the optical disc 14 side. However, even if the arrangement of the first diffraction grating 2a and the second diffraction grating 2b is changed, I do not care.

In addition, an aperture limiting film may be provided on any surface of the first transparent substrate 2g, the second transparent substrate 2h, the third transparent substrate 2j, and the fourth transparent substrate 2k through which two types of wavelengths of laser light are transmitted. good. The opening limiting film is, for example, a film in which an SiO ₂ film and at least one of a Si film and a Ti film are alternately stacked a plurality of times. The opening limiting film has an opening, transmits light incident on the opening, and absorbs light incident on the opening limiting film. The centers of the laser beams having two types of wavelengths are transmitted through the opening of the aperture limiting film. That is, since only the laser beam incident on the opening of the aperture limiting film passes, two types of laser beams having desired cross-sectional shapes can be obtained. The opening shape of the opening limiting film may be a substantially rectangular shape, a circular shape, an elliptical shape, an oval shape, or a polygon shape according to the optical design of the optical pickup device.

  The light diffracted and separated by the first diffraction grating 2a and the second diffraction grating 2b is arranged on the optical disk 14 as follows.

  FIG. 11A shows a spot arrangement on the CD according to the first embodiment, and FIG. 11B shows a spot arrangement on the 4.7 GB DVD-RAM according to the first embodiment. FIG. 11C shows the arrangement of spots on the DVD-R / RW in the first embodiment, and FIG. 11D shows another arrangement of spots on the DVD in the first embodiment. FIG. The laser light for CD and DVD emitted from the laser light source 1 is diffracted by the first diffraction grating 2a and the second diffraction grating 2b, respectively, and separated into zero-order light, ± first-order light,. Concentrate on top. On the optical disk 14, the focused spots are arranged in a substantially straight line with the 0th order light as the center,..., 1st order light, 0th order light, + 1st order light,. For tracking control, 0th order light and ± 1st order light are used. The zero order light is called the main beam, and the ± first order light is called the sub beam.

  With respect to the CD, as shown in FIG. 11A, the main beam 21a of the CD condensing spot 21 diffracted and separated by the first diffraction grating 2a is condensed on the CD track 14a. The two sub beams 21b are focused by 0.5 tracks away from each other in the opposite direction to the main beam 21a.

  There are two methods for arranging DVDs. First, as shown in FIGS. 11B and 11C, the main beam 22a and the sub beam 22b of the DVD condensing spot 22 diffracted by the second diffraction grating 2b are separated into the track 14b. Or the light is condensed at a relatively large angle on the track 14c. The pitch of the track 14b of the 4.7 GB DVD-RAM shown in FIG. 11B is 1.23 μm. The two sub beams 22b are focused by 1.5 tracks away from each other in the opposite direction to the main beam 22a. Therefore, the distance between the main beam 22a and the two sub beams 22b in the track direction is about 1.85 μm. The interval substantially corresponds to 2.5 tracks of the DVD-R / RW track 14c having a pitch of 0.74 μm shown in FIG. With this arrangement, DVD tracking control can be performed. The second method is a method of arranging the main beam 23a and the sub beam 23b on the same track 14d without tilting the tracks 14d of all types of DVDs as shown in FIG. 11 (d). With this arrangement, DVD tracking control can be performed.

  FIG. 12A is a configuration diagram of the beam splitter according to the first embodiment, and FIG. 12B is a configuration diagram of the beam splitter in which a light absorption film is formed. As shown in FIG. 12A, the beam splitter 3 is formed of optical glass or the like, and has an inclined surface 3a provided therein, and a polarization separation film 3b is formed on the inclined surface 3a. The polarization separation film 3b is composed of a multilayer dielectric film. The polarization separation film 3b transmits most of DVD laser light and CD laser light emitted from the laser light source 1 and being P-polarized light, and reflects a part thereof. In the first embodiment, about 85% is transmitted. The transmitted light is directed to the optical disc 14, and the reflected light is directed to the second light receiver 13. The polarization separation film 3b reflects 95% or more of the laser beam for DVD reflected by the optical disk 14 and converted to S-polarized light. Further, about 15% of the laser beam for CD that remains P-polarized light is reflected. The reflected light travels toward the light receiver 11.

  The amount of light traveling toward the second light receiver 13 is often too large for the second light receiver 13, and in this case, the light reducing member 12 is disposed between the beam splitter 3 and the second light receiver 13. This is because the polarization separation film 3b is designed so that the light traveling toward the optical disc 14 and the light traveling toward the light receiver 11 are optimized. The dimming member 12 reduces the amount of light traveling toward the second light receiver 13. In the case of the first embodiment, the dimming member 12 emits light without diverging unnecessary light, as compared with a configuration that reduces the amount of light by reflecting light. Absorbing forms are preferred. As shown in FIG. 12B, the light reducing member 12 may be a light absorbing film formed and provided on the surface of the beam splitter 3 that faces the second light receiver 13. The light absorbing film as the light reducing member 12 is a multilayer dielectric film. Since the light absorbing film is formed on the beam splitter 3 as the light reducing member 12, it is not necessary to newly provide components, and the optical pickup device 20 can be made inexpensive and light.

  FIG. 13A is a diagram illustrating the function of the detection lens according to the first embodiment, and FIG. 13B is a diagram illustrating the shape of the focused spot on the light receiving portion of the light receiving element of the light receiver when the optical disk is close. 13 (c) is a diagram showing a condensing spot shape on the light receiving portion of the light receiving element of the light receiver when the optical disk is far away. The detection lens 10 has different focal lengths in two orthogonal cross sections including the optical axis, and transmits the DVD laser light and the CD laser light reflected by the optical disk 14. In FIG. 13A, the detection lens 10 is a cylindrical lens. On one surface, the detection lens 10 functions as a flat plate for laser light in the vertical direction of the paper, and functions as a concave lens for laser light in the orthogonal direction. Long focal length. The opposite surface is a flat plate. Accordingly, when the light detection unit 11b of the light receiving element 11a of the light receiver 11 is arranged between the position where the laser beam in the vertical direction on the paper is focused and the position where the laser beam in the direction perpendicular to the focal point is focused, a substantially circular condensing light is collected. A spot appears at the center of the light detection unit 11b.

  As shown in FIG. 13B, when the optical disk 14 approaches the optical pickup device 20, the position where the laser beam in the vertical direction on the paper is focused approaches the light receiver 11, and the laser beam in the orthogonal direction is focused. Moves away from the light receiver 11. Therefore, the condensing spot of the detection part B and the detection part D becomes small, and the condensing spot of the detection part A and the detection part C becomes large. Conversely, as shown in FIG. 13C, when the optical disk 14 is moved away from the optical pickup device 20, the position where the laser beam in the vertical direction on the paper is focused is moved away from the light receiver 11, and the laser beam in the orthogonal direction is focused. The connecting position approaches the light receiver 11. Therefore, the condensing spot of the detection part B and the detection part D becomes large, and the condensing spot of the detection part A and the detection part C becomes small. The difference between the outputs of the detectors A and C and the outputs of the detectors B and D is used as a focus control signal. The detection lens 10 in the optical pickup device 20 of the first embodiment is disposed at an angle of 45 ° in a plane perpendicular to the optical axis. The outer shape of the lens unit itself is circular. As described above, by disposing the detection lens 10 according to the first embodiment, signals for focus control for DVD and CD can be obtained.

  FIG. 14A is a diagram showing the assembly of the light receiver of the first embodiment, and FIG. 14B is a configuration diagram of the light receiver. FIG. 15 is a layout diagram of the light receiving portions of the light receiving elements of the light receiver of the first embodiment. The light receiver 11 includes a light receiving element 11a having a light detecting portion 11b, and a wiring substrate 11d having a light transmitting portion 11f facing the light detecting portion 11b. The laser light reflected by the optical disk 14 and passing through the detection lens 10 passes through the light transmission part 11f and enters the light detection part 11b.

  Electrodes 11c connected to the wiring board 11d are arranged on the left and right ends of the same surface as the light detection portion 11b of the light receiving element 11a. As shown in FIG. 15, the light detection unit 11b includes DVD light detection units A to L and CD light detection units a to h. In the first embodiment, the wiring board 11d is a flexible printed circuit board (FPC). In the wiring board 11d, electrodes 11e with exposed conductive members are arranged in two rows to be connected to the electrodes 11c of the light receiving element 11a. The electrode 11e is connected to an insulated wiring member inside the wiring board 11d. A light transmission portion 11f is provided on the wiring substrate 11d between the two rows of electrodes 11e. In the first embodiment, the light transmission part 11f is a through hole of the wiring board 11d. However, the light transmission part 11f may be extended to the upper or lower end of the wiring board 11d to have a notch shape.

  In order to assemble the light receiver 11, first, the protruding electrode 11g is formed on the electrode 11c of the light receiving element 11a. In order to form the protruding electrode 11g, for example, there is a method of forming a gold ball with a gold wire and ultrasonically pressing the gold ball to the electrode 11c. An anisotropic conductive film (hereinafter referred to as ACF) 11h is attached to the electrode 11e of the wiring board 11d. ACF11h is a resin material containing conductive particles such as gold-plated balls. Next, the electrode 11c on which the protruding electrode 11g is formed and the electrode 11e to which the ACF 11h is attached are overlapped and thermocompression bonded. Then, since the conductive particles of the ACF 11h are captured and fixed between the protruding electrode 11g and the electrode 11e, the electrode 11c and the electrode 11e are electrically connected. Therefore, the wiring board 11d and the light receiving element 11a are electrically connected and fixed.

  Thus, the light receiver 11 includes the light receiving element 11a and the wiring board 11d. The light receiver 11 is in a state where the light receiving element 11a is not put in the package. A wiring substrate 11d having a light transmission part 11f is arranged on the light receiving element 11a side having the light detection part 11b. The size of the light receiver 11 in the thickness direction of the optical pickup device 20 can be reliably reduced as compared with the case where the light receiving element 11a is accommodated in the package. Therefore, the thickness of the optical pickup device 20 can be reduced. The arrangement direction of the electrodes 11 c incorporated in the optical pickup device 20 is a direction substantially perpendicular to the optical disk 14. Since the wiring board 11d necessary for the connection need not be wired from the thickness direction of the optical pickup device 20, the thickness of the optical pickup device 20 can be reduced.

  The laser beam for DVD and the laser beam for CD which are emitted from the laser light source 1, diffracted and separated by the diffraction element 2, reflected by the optical disk 14, and whose focal position is changed depending on the direction by the detection lens 10 are received by the light receiver 11. The light is incident on the light detector 11b. The DVD laser light is incident on the light receiving portions A, B, C, and D, and the sub beam is incident on the light receiving portions E, F, G, and H and the light receiving portions I, J, K, and L. The laser beam for CD is incident on the light receiving portions a, b, c, and d, and the sub beam is incident on the light receiving portions e and g and the light receiving portions f and h. The laser light incident on the light detection unit 11b is converted into an electric signal according to the amount of light incident on each light receiving unit and is output. The output signal is used for focus control and tracking control. Further, when information recorded on the optical disk 14 is reproduced, the information is also obtained from the output signal.

  The electric signals for DVD converted by entering the light receiving portions A, B, C, D, E, F, G, H, I, J, K, and L are converted into A, B, C, D, E, F, and G. , H, I, J, K, and L. The electric signals for CD that are incident on the light receiving portions a, b, c, d, e, f, g, and h and converted are a, b, c, d, e, f, g, and h. When the sub beam 22b is tilted, the DVD tracking error signal TE is DVD-ROM: TE = ph (A, D) -ph (B, C), DVD ± R / RW, -RAM: TE = {(A + B ) − (C + D)} − Kt × {(E + I + F + J) − (G + K + H + L)}. Here, ph (X, Y) is a voltage obtained by converting the detected phase difference between X and Y, and Kt is a constant determined according to the operation setting. The same applies when the sub beam 23b is not tilted.

  When the sub beam 22b is tilted, the DVD focus error signal FE is DVD-ROM, DVD ± R / RW: FE = (A + C) − (B + D), DVD-RAM: FE = {(A + C) − (B + D) } + Kt × {(E + I + G + K) − (H + L + F + J)}. The same applies when the sub beam 23b is not tilted.

  The tracking error signal TE for CD is CD-R / RW / ROM: TE = {(a + b)-(c + d)}-Kt × {(e + f)-(g + h)}, CD-ROM: ph (a, d ) -Ph (b, c). Usually, the former method is used which allows more stable tracking control. However, for example, when reproducing a bad disk whose CD-ROM pit height is not within the standard, the tracking error signal TE may not be output well by the former method. Even in such a case, the latter method can be used as a preliminary tracking control method because the tracking error signal TE can be output well. As described above, since it is possible to perform the tracking control even when reproducing a poor optical disk that is out of the standard that cannot be tracked, it is possible to deal with a wider range of optical disks 14 as an optical disk apparatus.

  The focus error signal FE for CD is CD−R / RW / ROM: FE = (a + c) − (b + d).

  FIG. 16 is a configuration diagram of the second light receiver of the first embodiment. The second light receiver 13 includes a light receiving element 13a having a light detection unit 13b, and a wiring substrate 13d having a light transmission unit 13f that passes the light separated from the light directed to the optical disk 14 facing the light detection unit 13b. Electrodes 13c connected to the wiring board 13d are arranged on the left and right ends of the same surface as the light detection unit 13b of the light receiving element 13a. The electrode 13c is electrically connected to the electrode 13e of the wiring board 13d. The configuration of the second light receiver 13 and the method of assembling are the same as those of the light receiver 11 except for the light detection unit 13b having a simple shape such as a quadrangle, and the description thereof is cited. The size of the second light receiver 13 in the thickness direction of the optical pickup device 20 can be surely reduced as compared with the case where the light receiving element 13a is accommodated in the package. In addition, the wiring board 13d necessary for connection need not be wired from the thickness direction of the optical pickup device 20. Thus, the thickness of the optical pickup device 20 can be reduced. The second light receiver 13 converts the received light into an electrical signal corresponding to the amount of laser light received and outputs the electrical signal. The output signal is used for output control of laser light emitted from the laser light source 1.

  The reflection mirror 4 is a mirror for bending the optical path in order to reduce the size of the optical pickup device 20. A total reflection film is formed on the surface of the reflection mirror 4.

  FIG. 17 is a configuration diagram of the collimating lens of the first embodiment. The collimating lens 5 is made of optical glass or optical plastic. The collimating lens 5 converts the laser beam for DVD and the laser beam for CD, which are diverging light emitted from the laser light source 1, into substantially parallel light. Further, the laser beam for DVD and the laser beam for CD, which are substantially parallel light reflected by the optical disk 14, are converted into focused light. The collimating lens 5 is a biconvex aspheric lens. Further, the side surface close to the optical disc 14 and the side surface on the opposite side have a flat surface 5a in which a part of the cylindrical surface is cut out by a plane parallel to the axis. The flat surface 5a may be scraped off or cut off from the side surface of the molded collimating lens 5, or may be molded into such a shape from the beginning. By adopting such a shape, the dimension of the collimating lens 5 in the thickness direction of the optical pickup device 20 can be reduced, and the thickness of the optical pickup device 20 can be reduced.

  The quarter-wave plate 6 has a phase that acts as a quarter-wave plate for laser light with a wavelength for DVD and does not substantially act as a wave plate for laser light with a wavelength for CD. ing. Therefore, the DVD laser light from the collimating lens 5 is converted from P-polarized light to circularly-polarized light. The laser beam for CD is transmitted as P-polarized light. Also, the DVD laser light reflected by the optical disk 14 is converted from circularly polarized light to S-polarized light. The laser beam for CD reflected by the optical disk 14 is transmitted as P-polarized light.

  The wedge-shaped prism 7 is a prism that is closer as the distance between the surface facing the collimating lens 5 and the surface facing the rising prism 8 is closer to the optical disk 14. The angle formed between the surface on the collimator lens 5 side and the surface on the rising prism 8 side is set to an angle inclined by about 1 ° to 3 ° from parallel. In Embodiment 1, the angle is set to 2.2 °. As shown in FIG. 2, the laser light emitted from the laser light source 1 that is substantially parallel to the optical disk 14 has a slight component in the direction perpendicular to the optical disk 14 by the wedge prism 7. That is, the optical axis is inclined by about 0.5 ° to 2 ° from a plane parallel to the optical disk 14. In the first embodiment, the angle is 0.9 °.

  As shown in FIG. 2, the rising prism 8 is a triangular prism that reflects twice inside to change the traveling direction of the laser light to a direction perpendicular to the recording surface of the optical disk 14. The distance between the optical disk 14 and the objective lens 9 cannot be made too small to prevent a collision. On the other hand, the laser beam emitted from the objective lens 9 toward the optical disc 14 must have a constant numerical aperture. For this reason, the diameter of the laser light emitted from the objective lens 9 cannot be made too small. From the time when the laser light emitted from the laser light source 1 is converted into substantially parallel light by the collimating lens 5 to the time when it enters the rising prism 8, the diameter is the same as the diameter of the laser light emitted from the objective lens 9. However, the thickness of the optical pickup device 20 cannot be reduced any more.

  Therefore, as shown in FIG. 2, the width of the component in the thickness direction of the optical pickup device 20 out of the light incident from the collimating lens 5 by the rising prism 8 is enlarged and incident on the objective lens 9, thereby collimating. The width in the thickness direction of the optical pickup device 20 required by the laser light from the lens 5 to the rising prism 8 can be reduced. For this purpose, a triangular rising prism 8 is used. That is, if the width of the laser beam incident on the rising prism 8 in the direction perpendicular to the optical disk 14 and perpendicular to the optical axis is X, and the width when the portion is emitted from the rising prism 8 is Y, Y / X is This corresponds to a value greater than 1. Y / X does not change much between the laser beam for DVD and the laser beam for CD. When Y / X is 1.10 or more, an effect of reducing the dimension of X begins to appear, and the thickness of the optical pickup device 20 can be reduced. If Y / X is 1.15 or more, the dimension of X is sufficiently small, which is more preferable. Moreover, Y / X can be appropriately designed by setting it to 1.50 or less. In the first embodiment, Y / X is 1.18. A collision between the optical disk 14 and the optical pickup device 20 can be suppressed, and a balance can be achieved with the optical pickup device 20 being thin.

  However, in order for the light emitted from the rising prism 8 to be in a direction that is exactly perpendicular to the objective lens 9, the direction of the laser light incident on the rising prism 8 is a component in a direction slightly perpendicular to the optical disk 14. It is necessary to have a direction. If the component in the vertical direction is left as it is, the distance from the laser light source 1 to the rising prism 8 is long, so the difference in height between the arranged laser light source 1 and the rising prism 8 becomes large, resulting in light The thickness of the pickup device 20 increases. Therefore, a wedge-shaped prism 7 is disposed between the collimating lens 5 and the rising prism 8, and the traveling direction of the laser light is parallel to the optical disk 14 until it enters the wedge-shaped prism 7 from the laser light source 1. The prism 7 has a slight component in the direction perpendicular to the optical disk 14. As a result, the diameter of the laser beam emitted from the objective lens 9 can be secured, the collision between the optical disk 14 and the optical pickup device 20 can be suppressed, and the thin optical pickup device 20 can be obtained. it can.

  The width of the laser beam in the direction parallel to the optical disk 14 does not change while passing through the rising prism 8. Conversely, since the width of the optical pickup device 20 in the thickness direction of the laser light passing through the collimating lens 5 is narrower than the width in the direction parallel to the optical disk 14, the flat surface 5a is formed on the side surface of the collimating lens 5 without affecting the performance. Can be given.

  The objective lens 9 is a bifocal lens and is made of optical glass or optical plastic. The laser light that has been made substantially parallel light by the collimator lens 5 is condensed by the objective lens 9 so as to be focused on the recording surface of the optical disk 14 corresponding to each wavelength. The objective lens 9 uses a combination of a condensing lens and a Fresnel lens or a hologram lens, or a combination of a condensing lens for DVD provided with aperture limiting means during CD reproduction, and absorbs differences in the thickness and numerical aperture of the optical disk 14. Can also be used.

  The optical disk 14 is a CD, a CD-ROM, a CD-R / RW, a DVD-ROM, a DVD ± R / RW, a DVD-RAM, etc. for a CD. All but recording and playback are possible. In the first embodiment, the CD and the DVD are used, but not only the combination but also the combination with a so-called BD, HD DVD or the like does not lose its generality.

  FIG. 18 is a configuration diagram of the base of the first embodiment. The base 15 is made of an alloy material such as a Zn alloy or an Mg alloy, or a hard resin material. In the first embodiment, it is necessary to make the optical pickup device 20 thin, and for this purpose, the base 15 must also be thin. It is desirable to use an alloy material that can easily ensure rigidity even if the base 15 is made thin. The thickness of the base 15 is a difference between the highest position and the lowest position in the thickness direction of the base 15, and is 3.5 mm or less. This is to reduce the thickness of the base 15 in order to aim for an ultra-thin optical disk device. If the strength can be ensured, the thickness is preferably 3.0 mm or less. In the first embodiment, the thickness of the base 15 is set to 2.6 mm in order to realize an optical disk device having a thickness of 7 mm.

  The base 15 has bearing portions 15a and 15b for attaching to the guide shaft of the optical disc apparatus. The bearing portion 15a is configured by fitting a cylindrical bearing 15q into the through hole 15p. The bearing 15 is made of a powder mainly composed of Cu or Cu alloy, which is hardened with a press and impregnated with a lubricant. However, if the thickness of the base 15 is as thin as 2.6 mm, the thickness of the bearing 15q must be reduced, and such a configuration may not be realized. In such a case, the bearing 15q may be a metal tube such as Cu or Cu alloy, and a lubricant may be provided on the inner periphery.

  The base 15 includes a laser module mounting portion 15c having a large opening and an objective lens driving device mounting portion 15d adjacent to each other. The laser module 17 is attached to the laser module attachment portion 15c, and the objective lens drive device 19 is attached to the objective lens drive device attachment portion 15d. A reference surface 15e for mounting the laser module 17 was provided on the outer side of the opening of the laser module mounting portion 15c. Further, the second light receiver mounting portion 15f, the reflection mirror mounting portion 15g, the collimator lens mounting portion 15h, and the quarter wavelength plate mounting portion 15j are used with reference to the reference surface 15e so that each optical component can be mounted with high accuracy in position and angle. A wedge-shaped prism mounting portion 15k and a rising prism mounting portion 15l are provided. The contact portion 15n of the collimating lens mounting portion 15h that contacts the collimating lens 5 and the grooves 15i formed outside the edges on both sides of the opening of the collimating lens mounting portion 15h are parallel to the axis of the collimating lens 5.

  FIG. 19A is a configuration diagram on the upper surface side of the coupling member of the first embodiment, and FIG. 19B is a configuration diagram on the lower surface side. The coupling member 16 has a shape in which an annular portion 16a is provided between substantially symmetrical arm portions 16b. The arm part 16b is in a position shifted from the center part of the annular part 16a. The coupling member 16 is preferably formed of a material that is relatively lightweight and has high precision shape workability, heat dissipation, and the like. For example, Zn, Zn alloy, Al, Al alloy, Ti, Ti alloy and the like are preferable. Used for. In the first embodiment, the coupling member 16 is configured by Zn die casting in consideration of cost and the like.

  The left and right arms 16b are provided with a reference surface 16c and a V-groove 16d at the tip. The reference surface 16c and the V groove 16d serve as a reference when assembling the laser module 17 or attaching the laser module 17 to the base 15. The surface of the annular portion 16a is in a direction substantially perpendicular to the reference surface 16c, and the reference surface 16c is the surface of the arm portion 16b on the side close to the central portion of the annular portion 16c. The surface of the annular portion 16a is also parallel to the axis of the V groove 16d.

  A contact surface 16f for fixing the plate 1c of the laser light source 1 is provided on the lower surface side of both the arm portions 16b and the annular portion 16a connected to the arm portions 16b. Each contact surface 16f is provided with a groove 16k and a recess 16l continuous to the groove 16k. Cream solder for fixing the plate 1c is disposed in the recess 16l, and flows into the plate 1c via the groove 16k to fix the plate 1c and the contact surface 16f of the coupling member 16. In the first embodiment, the concave portion 16l is disposed on the arm portion 16b side, and the groove 16k is disposed on the annular portion 16a side. When the cream solder arranged in the recess 16l melts and comes into contact with the plate 1c, it hardly flows into the groove 16k but flows into the plate 1c. Then, there is not much solder that contributes to fixing between the plate 1c and the contact surface 16f, and fixing does not work well. As a result, there are cases where the fixing strength is weak or the heat generated by the laser light source 1 cannot be released from the plate 1c to the coupling member 16 well. Therefore, it is preferable to dispose the recess 16l away from the plate 1c so that the solder melted in the recess 16l first flows into the groove 16k and then flows from the groove 16k to the plate 1c. However, it is difficult to secure a space for disposing the concave portion 16l in the annular portion 16a, and the concave portion 16l is provided on the arm portion 16b side.

  The main part of the laser light source 1 is accommodated in the space 16e of the annular portion 16a. The reason why the space 16e is not provided with a wall or the like is to provide a wall or the like so that the thickness of the laser module 17 does not increase. Instead, as a part of the annular portion 16a, the arms 16b are directly connected to ensure the strength of the coupling member 16. A lead 1d of the laser light source 1 is disposed at this connecting portion. Since the lead 1d is thin, it does not interfere with this connecting portion.

  On the other hand, a through hole 16g is provided on the side surface of the annular portion 16a opposite to the arm portion 16b, and a convex portion 16h is provided around the through hole 16g on the outer side surface portion of the annular portion 16a. The surface of the convex portion 16h was parallel to the reference surface 16c. The diffraction element 2 is fixed to the convex portion 16h. The laser beam emitted from the laser beam application 1 through the through hole 16g enters the diffraction element 2. Moreover, the wall part 16m extended from the lower surface side of the convex part 16h to the opposite side to the arm part 16b was provided, and the through-hole 16n was provided in the wall part 16m. The through-hole 16n is a hole for inserting a diffraction element holding member of a diffraction element assembling apparatus that arranges the diffraction element 2 and performs position adjustment and angle adjustment.

  Convex portions 16i are provided on both sides of the convex portion 16h. The plane created by the surface of the convex portion 16i is parallel to the reference surface 16c and is farther from the reference surface 16c than the convex portion 16h. The beam splitter 3 is disposed on the convex portion 16i. The beam splitter 3 is fixed by a wall portion 16m. Further, the wall portion 16m which is the annular portion 16a on one side of the convex portion 16h and the convex portion 16i is extended to provide a U-shaped contact surface 16j. The contact surface 16j is formed in a direction perpendicular to the reference surface 16c and perpendicular to a plane formed by connecting the axes of the V grooves 16d on both sides. The light receiver 11 is fixed to the contact surface 16j. The light receiving element 11a of the light receiver 11 is disposed at the center of the U-shape of the contact surface 16j.

  FIG. 20 is a configuration diagram of the laser module according to the first embodiment. The laser module 17 is configured by holding a laser light source 1, a diffraction element 2, a beam splitter 3, a detection lens 10, and a light receiver 11 as an integrated unit on a coupling member 16. In the laser light source 1, the plate 1c is fixed to the contact surface 16f. Fixing is performed by welding or bonding with an adhesive. It is preferable to weld using a metal such as cream solder because heat generated by the laser light source 1 can be easily released to the coupling member 16 because of high thermal conductivity. As the adhesive, a thermosetting adhesive, an anaerobic adhesive, or the like is used. When fixing, the position adjustment in the X direction and the Z direction and the angle adjustment in the θy direction in the in-plane direction of the plate 1c and the contact surface 16f are performed. Since the plate 1c having a large area is fixed to the coupling member 16, good and stable assembly accuracy can be realized.

  The diffraction element 2 is fixed to the convex portion 16h by adhesion. The beam splitter 3 is fixed to the convex portion 16i by adhesion. An adhesive such as an ultraviolet curable adhesive, a thermosetting adhesive, or an anaerobic adhesive is used for bonding the diffraction grating 2 and the beam splitter 3. The diffraction element 2 performs position adjustment in the X direction and Y direction and angle adjustment in the θz direction. The adjustment in the X direction and the Y direction may not be performed as long as the assembling apparatus has a high accuracy of arranging the diffraction element 2 on the coupling member 16 first. However, when the diffraction element 2 includes the second diffraction grating 2b for DVD in which the diffracted light is arranged as shown in FIG. 11D, it is preferable to adjust the position in the Y direction. The diffraction element 2 is rotated and adjusted in the θz direction so that the straight line connecting the main beam of the DVD and the main beam of the CD and the straight line connecting the sub beams on both sides of the DVD are at a predetermined angle. This adjustment is to adjust the direction in which the light emitting point of the DVD and the light emitting point of the CD are aligned and the direction in which the first diffraction grating 2a and the second diffraction grating 2b of the diffraction element 2 are aligned. And each light beam of the CD can be made incident on a predetermined light detection unit 11 b of the light receiver 11. The direction in which the first diffraction grating 2a and the second diffraction grating 2b are arranged is adjusted with high precision when the diffraction element 2 is manufactured, and thus is adjusted using a DVD sub-beam diffracted by the second diffraction grating 2b. Then, the CD sub-beam is automatically adjusted. The beam splitter 3 adjusts the position in the X direction. Further, adjustment in the Z direction may be performed.

  The detection lens 10 is fixed to a detection lens holder 10a fixed to the light receiver 11 in advance. The detection lens 10 is applied to the detection lens holder 10a, and the position adjustment in the Y and Z directions and the angle adjustment in the θx direction between the detection lens 10 and the light receiving element 11a of the light receiver 11 are performed. A detection lens holder 10 a to which the detection lens 10 and the light receiver 11 are attached is fixed to the contact surface 16 j of the coupling member 16. Position adjustment in the X direction, Y direction, and Z direction, and angle adjustment in the θx direction, θy direction, and θz direction are performed on the coupling member 16. For fixing the light receiver 11 and the detection lens holder 10a, fixing the detection lens holder 10a and the detection lens 10, and fixing the detection lens holder 10a and the coupling member 16, respectively, an ultraviolet curable adhesive and a thermosetting adhesive Adhesives such as anaerobic adhesives are used.

  In order to correspond to the thin optical pickup device 20, the coupling member 16 is also thin. However, the distance between the optical components fixed to the coupling member 16 can be reduced. It is assumed that each optical component of the laser module 17 is fixed to the base 15 instead of the coupling member 16. Since the thickness of the base 15 is as thin as 2.6 mm as described above, it tends to be easily deformed by stresses such as temperature and changes with time. For this reason, positional deviation or angular deviation between the optical components may occur. However, since the coupling member 16 is small, it is difficult to be deformed due to stress such as temperature and change with time. That is, a laser light source 1 that emits laser light, a diffraction element 2 that generates tracking control light, a beam splitter 3 that separates forward light and return light, and a detection lens that generates focus control light By fixing the optical receiver 10 and the light receiver 11 that receives laser light to the coupling member 16, it is possible to obtain an effect of making it difficult for positional deviation and angular deviation between the optical components to occur. Therefore, stable and high quality recording / reproducing characteristics can be obtained.

  FIG. 21 is a configuration diagram of the objective lens driving device according to the first embodiment. In the first embodiment, in the objective lens driving device 19, the objective lens 9, the focus coil 19d, and the tracking coil 19e are fixed at predetermined positions of the lens holder 18. An elastic support member holder 19b is fixed to a yoke 19c to which a magnet 19f is fixed, and this is called an apparatus main body. One end of the elastic support member 19a is fixed to the lens holder 18, and the other end is fixed to the elastic support member holder 19b. The lens holder 18 is elastically supported by the elastic support member 19a. A drive current is passed from the elastic support member 19a to the focus coil 19d or the tracking coil 19e. An electromagnetic force is generated in the focus coil 19d or the tracking coil 19e between the magnetic field of the magnet 19f. The lens holder 18 on which the objective lens 9 is mounted is driven in the focus direction or the tracking direction by the generated electromagnetic force. The drive current that flows through the focus coil 19d or the tracking coil 19e is controlled by an electrical signal that is converted from the amount of laser light incident on the light receiver 11 and output.

  As shown in FIG. 1, the optical pickup device 20 according to the first embodiment is configured by attaching various components to a base 15 directly or via other components. In the laser module 17, the reference surface 16 c of the coupling member 16 is fixed to the reference surface 15 e of the base 15. The main part of the laser module 17 is accommodated in the laser module mounting part 15c. The laser module 17 is adjusted in position and angle in the plane of the reference plane 16c and the reference plane 15e. For fixing, an adhesive such as an ultraviolet curable adhesive, a thermosetting adhesive, or an anaerobic adhesive is used.

  The main body of the objective lens driving device 19 equipped with the objective lens 9 is fixed to the base 15. The objective lens driving device 19 is accommodated in the objective lens driving device mounting portion 15 d of the base 15. When the objective lens driving device 19 is fixed to the base 15, position adjustment and angle adjustment of the objective lens 9 are performed. For fixing, an adhesive such as an ultraviolet curable adhesive, a thermosetting adhesive, or an anaerobic adhesive is used. The reflecting mirror 4 is mounted on the reflecting mirror mounting portion 15g of the base 15, the quarter wavelength plate 6 is mounted on the quarter wavelength plate mounting portion 15j, and the wedge prism 7 is mounted on the wedge prism mounting portion 15k. 8 is directly fixed to the rising prism mounting portion 15l, and the light reducing member 12 and the second light receiving device 13 are directly fixed to the second light receiving device mounting portion 15f. For fixing, an adhesive such as an ultraviolet curable adhesive, a thermosetting adhesive, or an anaerobic adhesive is used.

  In order to assemble the optical pickup device 20, first, the reflecting mirror 4, the quarter wavelength plate 6, the wedge prism 7, and the rising prism 8 are respectively connected to the reflecting mirror attaching portion 15g and the quarter wavelength plate attaching portion of the base 15. 15j, wedge-shaped prism mounting portion 15k, and rising prism mounting portion 151 are fixed or finely adjusted in position and angle. Further, the collimating lens 5 is attached to the base 15. As will be described later, the collimating lens 5 is attached so as to be movable in the optical axis direction. Next, the laser module 17 is attached to the base 15. Then, the reference surface 16c of the coupling member 16 is brought into close contact with the reference surface 15e of the base 15, and the position adjustment in the X direction and the Y direction and the angle adjustment in the θz direction are performed. Laser light is emitted and position adjustment in the X and Y directions is performed so as to pass through the center of the collimating lens 5. Further, angle adjustment in the θz direction is performed so that the main beam and the sub beam are incident on the track of the optical disk 14 at a predetermined angle. Then, the laser module 17 is fixed to the base 15. Next, the objective lens driving device 19 is attached to the objective lens driving device attaching portion 15 d of the base 15. Laser light is emitted to adjust the angle of the objective lens 9 in the θx direction and θy direction by moving the entire objective lens driving device 19. Next, the position of the objective lens 9 in the X and Y directions is adjusted by moving the entire objective lens driving device 19 so that the laser beam passes through the center of the objective lens 9, and the objective lens driving device 19 is fixed to the base 15. . Next, the position of the collimating lens 5 is adjusted in the optical axis direction (X direction). Further, the light reducing member 12 and the second light receiver 13 are separately fixed to the second light receiver mounting portion 15 f of the base 15.

  FIG. 22 is a diagram in which the heat dissipating member of the first embodiment is arranged. One end of the heat radiating member 24 was fixed to the back surface of the plate 1 c of the laser light source 1, and the other end of the heat radiating member 24 was fixed to a predetermined position of the base 15. One end and the other end of the heat dissipating member 24 are widened to increase the contact area between the plate 1c and the base 15. In the first embodiment, the heat radiating member 24 is a graphite sheet. The graphite sheet has high thermal conductivity especially in the in-plane direction, and is suitable for releasing heat. The heat radiating member 24 was fixed to the plate 1c and the base 15 with a thin adhesive. With this configuration, the heat generated in the light emitting element 1a in the laser light source 1 and transmitted to the plate 1c can be released from the base 15 via the heat radiating member 24, so that it is released only from the coupling member 16. More heat can be released than if. Therefore, the light emitting element 1a of the laser light source 1 can be operated more stably because temperature rise is suppressed to a smaller extent. When the heat radiating member 24 is made of a graphite sheet, the graphite sheet has high thermal conductivity and can transmit more heat to the base 15, so that the temperature rise of the light emitting element 1a of the laser light source 1 can be suppressed less. It can operate stably.

  FIG. 23A is a perspective view showing a state where the collimating lens is fixed to the base of the first embodiment, FIG. 23B is a cross-sectional view showing a method of fixing the collimating lens, and FIG. It is sectional drawing which shows the fixed state of a collimating lens.

  The collimating lens 5 is arranged from the base 15 main body side to the collimating lens mounting portion 15 h that is the main body side of the base 15. At this time, either one of the flat surfaces 5a of the collimating lens 5 is set close to the optical disc 14 so as to face the opening 15m of the collimating lens mounting portion 15h. The fixing member 25 is arranged from the side of the opening 15m that is not the base 15 main body side. The fixing member 25 has a shape in which both end portions of the plate-like member are bent in the same direction. The bent end is hooked in a groove 15 i provided outside the edge of the opening 15 m of the base 15. In this state, there is a gap between the fixing member 25 and the plane 5a of the objective lens 5. The central portion of the fixing member 25 is pressed and deformed toward the objective lens 5 to be fixed to the flat surface 5 a of the objective lens 5. For fixing, an adhesive such as an ultraviolet curable adhesive, a thermosetting adhesive, or an anaerobic adhesive is used. The fixing member 25 is fixed in a state where it is warped toward the collimating lens 5, and is fixed by pulling the objective lens 5 toward the base 15 with a force for returning to the original shape. The material constituting the fixing member 25 is an elastic material such as phosphor bronze, beryllium copper, SUS, titanium or the like. However, as long as the balance conditions such as the amount of deformation and the force required for deformation are met, a material such as a bimetal such as Invar-brass, a material such as a shape memory alloy such as nickel-titanium, copper-aluminum-nickel alloy, etc. It doesn't matter. The thickness necessary for fixing the objective lens 5 is minimal due to the thickness of the fixing member 25 and the amount of warping of the fixing member 25, and the thickness of the optical pickup device can be reduced.

  The contact portion 15 n and the groove 15 i that come into contact with the collimating lens 5 of the base 15 are formed to be parallel to the optical axis of the laser beam that passes through the collimating lens 5. The fixing member 25 and the base 15 are not bonded to each other, and the fixing member 25 can be slid in the direction of arrow D in FIG. 23A as a guide at both ends where the groove 15i of the base 15 is bent. . After the collimating lens 5 is attached to the base 15, precise position adjustment in the optical axis direction is necessary. By sliding the fixing member 25 along the contact portion 15n and the groove 15i parallel to the optical axis, the position in the optical axis direction can be adjusted without changing the posture of the collimating lens 5. Further, the collimating lens 5 can be fixed as it is at the position where the position adjustment is completed.

  The laser module 17 may form a contact surface for attaching the second light receiver 13 at a predetermined position of the coupling member 16, and the second light receiver 13 may be fixed to the contact surface. At this time, the light reducing member 12 is preferably a light absorbing film provided on the surface of the beam splitter 3 facing the second light receiver 13 as shown in FIG. Since the distance from the beam splitter 3 can be shortened, all the light emitted from the beam splitter 3 can be incident on the second light receiver 13, and the generation of stray light can be suppressed. Further, since the distance from the beam splitter 3 can be shortened, the spectral pickup device 20 can be downsized. The second light receiver mounting portion 15f provided on the base 15 can be omitted.

  The optical path will be described. In FIG. 2, laser beams of two types of wavelengths for DVD and CD are emitted by the light emitting element 1 a of the laser light source 1 and emitted from the laser light source 1 toward the optical disk 14. Laser light of two types of wavelengths emitted from the laser light source 1 enters the diffraction element 2. The laser beam for CD is diffracted and separated by the first diffraction element 2a, and the laser beam for DVD is diffracted and separated by the second diffraction grating 2b, and each is used to generate tracking control light. Next, laser beams of two types of wavelengths are incident on the beam splitter 3, and most of the laser light is emitted as it is toward the optical disk 14. A part of the light is reflected by the polarization separation film 3 b on the inclined surface 3 a and travels to the second light receiver 13. Laser light of two types of wavelengths that have been appropriately lightened by the light reducing member 12 enters the second light receiver 13 and is converted into an electrical signal. The converted electrical signal output from the second light receiver 13 is used for controlling the amount of laser light emitted from the laser light source 1. The two types of laser beams emitted from the beam splitter 3 toward the optical disc 14 are reflected by the reflection mirror 4, bent at the optical path, and incident on the collimating lens 5. The laser light having two types of wavelengths that has been diverging light is converted into substantially parallel light by the collimating lens 5 and enters the quarter-wave plate 6. The laser beam for DVD is converted from P-polarized light to circularly-polarized light by the quarter wavelength plate 6. The laser beam for CD passes through the quarter-wave plate 6 with P polarization. The laser light of two types of wavelengths incident on the wedge prism 7 is changed by changing the optical path that has been approximately parallel to the optical disk 14 until it has a component having a direction perpendicular to the optical disk 14 slightly. The light enters the raising prism 8. The two types of laser beams incident on the rising prism 8 are reflected twice inside and then emitted in a direction perpendicular to the optical disk 14. Further, the width of the light beam in the direction perpendicular to the optical disk 14 incident on the rising prism 8 is widened and emitted from the rising prism 8. Laser light of two types of wavelengths emitted from the rising prism 8 is incident on the objective lens 9, converted into focused light, and focused on the recording surface of each optical disk 14.

  Laser light of two types of wavelengths for DVD and CD reflected by the optical disk 14 is converted into parallel light by the objective lens 9 and enters the rising prism 8. The two kinds of laser light beams are changed by the rising prism 8 in a direction having a slight component in a direction perpendicular to the optical disk 14 and enter the wedge-shaped prism 7, and the wedge-shaped prism 7 applies the light to the optical disk 14. Change in almost parallel directions. The laser beam for DVD is converted from circularly polarized light to S polarized light by the quarter wavelength plate 6. The laser beam for CD passes through the quarter-wave plate 6 with P polarization. The laser light having two types of wavelengths, which is parallel light, is converted into focused light by the collimator lens 5. The two types of laser beams emitted from the collimator lens 5 are reflected by the reflection mirror 4 and enter the beam splitter 3. Two types of laser beams reflected by the polarization separation film 3b on the inclined surface 3a of the beam splitter 3 with their respective reflectances enter the detection lens 10. Laser beams of two types of wavelengths are converted into light beams having different focal positions depending on directions by the detection lens 10, and are respectively used for generating focus control light. Laser light of two types of wavelengths emitted from the detection lens 10 enters the light receiver 11. The light receiver 11 receives laser light of two types of wavelengths by the light detection unit 11b of the light receiving element 11a, converts the received light amount into an electrical signal, and outputs it. The output electric signal is calculated as a tracking error signal and a focus error signal and used for tracking control and focus control of the objective lens 9.

  Note that the temperature of the laser light source 1 rises as it continues to emit light at a high output. As the temperature rises, the polarization plane of the laser light emitted from the laser light source 1 that was only P-polarized light rotates to have an S-polarized component. As a result, the amount of light incident on the second light receiver 13 may fluctuate. Removing the S-polarized light component incident on the second light receiver 13 is one effective means for suppressing this phenomenon. For this purpose, a polarizing film may be disposed between the beam splitter 3 and the second light receiver 13, or a prism having a polarization separation film that transmits P-polarized light and reflects S-polarized light may be disposed on the inner slope. good.

  In the first embodiment, light used for CD tracking control is diffracted by the first diffraction grating 2a of the diffraction element 2, and light used for DVD tracking control is generated by diffracting by the second diffraction grating 2b. . Further, the detection lens 10 generates light used for focus control of DVD and CD. As a result, the function of generating the tracking control light and the function of generating the focus control light possessed by the hologram can be allocated to the diffraction element 2 and the detection lens 10, and the hologram can be omitted. Therefore, the hologram can be omitted and the distance between the start-up prism 8 and the objective lens 9 can be minimized while ensuring sufficient recording and reproduction performance for two types of optical disks 14 corresponding to laser beams of different wavelengths such as DVD and CD. . Therefore, it is possible to realize a thin optical pickup device 20 used for a thin optical disk device having a thickness of 7 mm.

(Embodiment 2)
The second embodiment will be described with reference to the drawings. The second embodiment is an optical pickup device having an optical system that separates laser light incident on a second light receiver with a reflecting mirror instead of a beam splitter. That is, the reflection mirror functions as a second beam splitter.

  FIG. 24 is a block diagram of the optical pickup device of the second embodiment, and FIG. 25 is a block diagram of an optical system of the optical pickup device of the second embodiment. Except for the beam splitter 3, the second beam splitter 26 modified from the reflection mirror 4, the abolished dimming member 12, and the base 15 in which the position of the second light receiver mounting portion 15 f is changed, it is the same as in the first embodiment. Therefore, the explanation is used. In FIG. 24, projection from the laser light source 1 to the quarter-wave plate 6 is performed on a plane parallel to the optical disc 14, and projection from the wedge prism 7 to the optical disc 14 is projected onto a plane perpendicular to the optical disc 14. It is.

  The beam splitter 3 is formed of optical glass or the like, and an inclined surface 3a is provided therein, and a polarization separation film 3b is formed on the inclined surface 3a. The polarization separation film 3b is composed of a multilayer dielectric film. Since the polarization separation film 3b does not need to separate the light toward the second light receiver 13, it transmits 95% or more of the DVD laser light emitted from the laser light source 1 and is P-polarized light, and transmits the laser light for CD. Transmits about 85%. The polarization separation film 3b reflects 95% or more of the laser beam for DVD reflected by the optical disk 14 and converted to S-polarized light. Further, about 15% of the laser beam for CD that remains P-polarized light is reflected. The reflected light travels toward the light receiver 11.

  The second beam splitter 26 is a mirror for bending the optical path in order to reduce the size of the optical pickup device 20. Further, a part of the laser light having two types of wavelengths emitted from the laser light source 1 is separated so as to be directed to the second light receiver 13. A separation film 26 a is formed on the surface of the second beam splitter 26 facing the beam splitter 3 and the collimating lens 5. The separation film 26a reflects about 90% of light and transmits about 10% of light. The two types of laser beams emitted from the laser light source 1 and transmitted through the second beam splitter 26 are incident on the second light receiver 13. The second light receiver 13 converts the received light into an electrical signal corresponding to the amount of laser light received and outputs the electrical signal. The output signal is used for output control of laser light emitted from the laser light source 1. Since the second beam splitter 26 dims and an appropriate amount of light enters the second light receiver 13, the dimming member 12 is unnecessary.

  The position of the second light receiver mounting portion 15f of the base 15 has moved to the opposite side of the laser module mounting portion 15c with the second beam splitter mounting portion 15o whose name has been changed from the reflecting mirror mounting portion 15g interposed therebetween.

  The optical path will be described. In FIG. 25, laser light of two types of wavelengths for DVD and CD is emitted by the light emitting element 1a of the laser light source 1 and emitted from the laser light source 1 toward the optical disk. Laser light of two types of wavelengths emitted from the laser light source 1 enters the diffraction element 2. The laser beam for CD is diffracted and separated by the first diffraction element 2a, and the laser beam for DVD is diffracted and separated by the second diffraction grating 2b, and each is used to generate tracking control light. Next, laser beams of two types of wavelengths are incident on the beam splitter 3 and are emitted toward the optical disc 14 as they are. The laser light having two types of wavelengths emitted from the beam splitter 3 toward the optical disc 14 is reflected by the separation film 26a of the second beam splitter 26, and most of the light is reflected toward the optical disc 14, and a part of the light is emitted by the separation film 26a. The light passes through and travels toward the second light receiver 13. Laser light of two types of wavelengths enters the second light receiver 13 and is converted into an electrical signal. The converted electrical signal output from the second light receiver 13 is used for controlling the amount of laser light emitted from the laser light source 1. The two types of laser beams reflected by the second beam splitter 26 are incident on the collimating lens 5 by bending the optical path. The laser light having two types of wavelengths that has been diverging light is converted into substantially parallel light by the collimating lens 5 and enters the quarter-wave plate 6. The laser beam for DVD is converted from P-polarized light to circularly-polarized light by the quarter wavelength plate 6. The laser beam for CD passes through the quarter-wave plate 6 with P polarization. The laser light of two types of wavelengths incident on the wedge prism 7 is changed by changing the optical path that has been approximately parallel to the optical disk 14 until it has a component having a direction perpendicular to the optical disk 14 slightly. The light enters the raising prism 8. The two types of laser beams incident on the rising prism 8 are reflected twice inside and then emitted in a direction perpendicular to the optical disk 14. Further, the width of the light beam in the direction perpendicular to the optical disk 14 incident on the rising prism 8 is widened and emitted from the rising prism 8. Laser light of two types of wavelengths emitted from the rising prism 8 is incident on the objective lens 9, converted into focused light, and focused on the recording surface of each optical disk 14.

  Laser light of two types of wavelengths for DVD and CD reflected by the optical disk 14 is converted into parallel light by the objective lens 9 and enters the rising prism 8. The two kinds of laser light beams are changed by the rising prism 8 in a direction having a slight component in a direction perpendicular to the optical disk 14 and enter the wedge-shaped prism 7, and the wedge-shaped prism 7 applies the light to the optical disk 14. Change in almost parallel directions. The laser beam for DVD is converted from circularly polarized light to S polarized light by the quarter wavelength plate 6. The laser beam for CD passes through the quarter-wave plate 6 with P polarization. The laser light having two types of wavelengths, which is parallel light, is converted into focused light by the collimator lens 5. Most of the two types of laser beams emitted from the collimator lens 5 are reflected by the separation film 26 a of the second beam splitter 26 and enter the beam splitter 3. Two types of laser beams reflected by the polarization separation film 3b on the inclined surface 3a of the beam splitter 3 with their respective reflectances enter the detection lens 10. Laser beams of two types of wavelengths are converted into light beams having different focal positions depending on directions by the detection lens 10, and are respectively used for generating focus control light. Laser light of two types of wavelengths emitted from the detection lens 10 enters the light receiver 11. The light receiver 11 receives laser light of two types of wavelengths by the light detection unit 11b of the light receiving element 11a, converts the received light amount into an electrical signal, and outputs it. The output electric signal is calculated as a tracking error signal and a focus error signal and used for tracking control and focus control of the objective lens 9.

  In the second embodiment, similarly to the first embodiment, light used for CD tracking control is generated by diffracting by the first diffraction grating 2a of the diffraction element 2, and diffracted by the second diffraction grating 2b. The light used for tracking control was generated. Further, the detection lens 10 generates light used for focus control of DVD and CD. As a result, the function of generating the tracking control light and the function of generating the focus control light possessed by the hologram can be allocated to the diffraction element 2 and the detection lens 10, and the hologram can be omitted. Therefore, the hologram can be omitted and the distance between the start-up prism 8 and the objective lens 9 can be minimized while ensuring sufficient recording and reproduction performance for two types of optical disks 14 corresponding to laser beams of different wavelengths such as DVD and CD. . Therefore, it is possible to realize a thin optical pickup device 20 used for a thin optical disk device having a thickness of 7 mm.

(Embodiment 3)
The third embodiment will be described with reference to the drawings. The third embodiment is an optical disk device provided with the optical pickup device of the first or second embodiment. FIG. 26A is a top configuration diagram of the optical pickup module of the third embodiment, FIG. 26B is a bottom configuration diagram, and FIG. 27 is a configuration diagram of the optical disc apparatus of the third embodiment.

  In FIG. 26, the drive mechanism of the optical disk device 40 including a rotation drive unit that rotates the optical disk 14 and a moving unit that moves the optical pickup device 20 closer to or away from the rotation drive unit is referred to as an optical pickup module 30. The base 31 forms a framework of the optical pickup module 30, and the optical pickup module 30 is configured by arranging each component directly or indirectly on the base 31.

  The rotation drive unit includes a spindle motor 32 having a turntable 32a on which the optical disk 14 is placed. The spindle motor 32 is fixed to the base 31. The spindle motor 32 generates a rotational driving force that rotates the optical disk 14.

  The moving unit includes a feed motor 33, a screw shaft 34, and guide shafts 35 and 36. The feed motor 33 is fixed to the base 31. The feed motor 33 generates a rotational driving force necessary for the optical pickup device 20 to move between the inner periphery and the outer periphery of the optical disc 14. A stepping motor, a DC motor, or the like is used as the feed motor 33. The screw shaft 34 has a groove formed in a spiral shape, and is connected to the feed motor 33 directly or via several stages of gears. In the third embodiment, it is connected to the feed motor 33 through a gear. The guide shafts 35 and 36 are fixed to the base 31 via holding members at both ends. The guide shafts 35 and 36 support the optical pickup device 20 so as to be movable. The optical pickup device 20 includes a rack 37 having guide teeth that mesh with the grooves of the screw shaft 34. Since the rack 37 converts the rotational driving force of the feed motor 33 transmitted to the screw shaft 34 into a linear driving force, the optical pickup device 20 can move between the inner periphery and the outer periphery of the optical disk 14.

  Note that the rotation driving unit is not limited to the configuration described in the third embodiment as long as it can rotate the optical disc 14 at a predetermined rotation speed. The moving unit is not limited to the configuration described in the third embodiment as long as it can move the optical pickup device 20 to a predetermined position between the inner periphery and the outer periphery of the optical disc 14.

  The optical pickup device 20 is configured by attaching a cover 29 to the configuration of FIG. 1 or FIG. In the optical pickup device 20, the laser light source 1, the diffraction element 2, the beam splitter 3, the detection lens 10, and the light receiver 11 are fixed to the coupling member 16 to form a laser module 17, and the coupling member 16 is fixed to the base 15. In order to realize the optical disk device 40 having a thickness of 7 mm, the thickness of the base 15 is 2.6 mm. Since the laser module 17 has sufficient strength, the positional deviation and angular deviation of each component in the laser module 17 are small. Therefore, even if the base 15 is made thin in order to make the optical pickup device 20 thin, high-quality recording and reproduction with respect to the optical disc 14 can be maintained. Therefore, the distance between the rising prism 8 and the objective lens 9 can be minimized while ensuring sufficient recording / reproducing performance for two types of optical disks 14 corresponding to laser beams of different wavelengths such as DVD and CD. Therefore, the optical pickup device 20 used in the third embodiment can be made very thin. The inclination of the guide shafts 35 and 36 is adjusted by an adjustment mechanism that constitutes a holding member so that the laser light emitted from the objective lens 9 of the optical pickup device 20 is incident on the optical disk 14 at a right angle.

  The FPC 38 electrically connects the optical pickup device 20 and the main body of the optical disk device 40. The FPC 38 is a conductive wire for supplying electric power to the optical pickup device 20 from the main body side of the optical disk device 40 and sending an electric signal, and for sending an electric signal from the optical pickup device 20 to the main body side of the optical disk device 40. It is also a conductive wire.

  The cover 39 has an opening to expose the objective lens 9 of the optical pickup device 20 and the turntable 32a of the spindle motor 32. Further, in the case of the third embodiment, the feed motor 33 and the guide shaft 36 are also exposed so that the thickness of the optical pickup module 30 is reduced by the thickness of the cover 39.

  In FIG. 27, the casing 41 is configured by combining an upper casing 41a and a lower casing 41b and fixing them together using screws or the like. The tray 42 is provided in the casing 41 so as to be able to appear and retract. The tray 42 arranges the optical pickup module 30 from the lower surface side. The tray 42 has an opening and exposes at least a part of the objective lens 9, the turntable 32 a of the spindle motor 32, and the cover 39. The bezel 43 is provided on the front end surface of the tray 42 and is configured to close the entrance / exit of the tray 42 when the tray 42 is stored in the housing 41. The bezel 43 is provided with an eject switch 44. When the eject switch 44 is pressed, the engagement between the housing 41 and the tray 42 is released, and the tray 42 can be brought into and out of the housing 41. The rails 45 are slidably attached to both sides of the tray 42 and the housing 41, respectively. There is a circuit board (not shown) inside the housing 41 and the tray 42, and a signal processing system IC, a power circuit, and the like are mounted. The external connector 46 is connected to a power / signal line provided in an electronic device such as a computer. Then, power is supplied into the optical disc device 40 via the external connector 46, an electric signal from the outside is guided into the optical disc device 40, or an electric signal generated by the optical disc device 40 is sent to an electronic device or the like. To do.

  As described above, the optical pickup device 20 mounted on the optical disk device 40 according to the third embodiment generates light used for CD tracking control by diffracting by the first diffraction grating 2a of the diffraction element 2, and the second diffraction. Light used for DVD tracking control was diffracted by the grating 2b. Further, the detection lens 10 generates light used for focus control of DVD and CD. As a result, the function of generating the tracking control light and the function of generating the focus control light possessed by the hologram can be assigned to the diffraction element 2 and the detection lens 10, and the hologram can be omitted. Therefore, the hologram can be omitted and the distance between the start-up prism 8 and the objective lens 9 can be minimized while ensuring sufficient recording and reproduction performance for two types of optical disks 14 corresponding to laser beams of different wavelengths such as DVD and CD. . Therefore, the optical pickup device 20 can be made very thin. Therefore, the optical disk device 40 according to the third embodiment on which the optical pickup device 20 is mounted can also be made very thin with a thickness of 7 mm.

  As described above, the optical pickup device and the optical disk device according to the present invention have the rising prism and the objective lens while ensuring sufficient recording / reproduction performance for two types of optical disks corresponding to laser beams of different wavelengths such as DVD and CD. And can be made thin by minimizing the distance between them. Therefore, it is particularly preferred to be mounted on electronic devices such as thin personal computers and notebook computers.

Configuration diagram of optical pickup device according to Embodiment 1 Configuration diagram of an optical system of the optical pickup device of the first embodiment Configuration diagram of laser light source according to the first embodiment (A) Configuration diagram of diffraction grating according to the first embodiment, (b) Cross-sectional view along plane A, (c) Cross-sectional view along plane B, (d) Cross-sectional view along plane C (A) The figure which shows the principle of the diffraction grating of this Embodiment 1, (b) The figure which shows the relationship between the wavelength of each diffraction grating, and refractive index (A) The block diagram of the other example 1 of the diffraction element of this Embodiment 1, (b) The figure which shows the relationship between the wavelength of each diffraction grating, and refractive index (A) The block diagram of the other example 2 of the diffraction element of this Embodiment 1, (b) The figure which shows the relationship between the wavelength of each diffraction grating, and refractive index (A) Configuration diagram of another example 3 of the diffraction element according to the first embodiment, (b) Configuration diagram of another example 4, (c) Configuration diagram of another example 5, (d) Configuration example of another example 6. Diagram (A) Configuration diagram of another example 7 of the diffraction element according to the first embodiment, (b) Cross-sectional view by plane A, (c) Bottom view, (d) Top view (A) Configuration diagram of another example 8 of the diffraction element according to the first embodiment, (b) is a sectional view taken along the plane A, (c) is a sectional view taken along the plane B, and (d) is a top view. (A) The figure which shows the arrangement | sequence of the spot on CD of this Embodiment 1, (b) The figure which shows the arrangement | sequence of the spot on 4.7-GB DVD-RAM of this Embodiment 1, (c) This embodiment The figure which shows the arrangement | sequence of the spot on DVD-R / RW of form 1, (d) The figure which shows the method of another arrangement of the spot on DVD of this Embodiment 1 (A) Configuration diagram of the beam splitter of the first embodiment, (b) Configuration diagram of the beam splitter formed with the light absorption film (A) The figure which shows the function of the detection lens of this Embodiment 1, (b) The figure which shows the condensing spot shape on the light-receiving part of the light receiving element of the optical receiver when the optical disk is near, (c) The optical disk is far Of the condensing spot shape on the light receiving part of the light receiving element of the photoreceiver (A) The figure which shows the assembly of the light receiver of this Embodiment 1, (b) The block diagram of a light receiver Arrangement of the light receiving portion of the light receiving element of the light receiver of the first embodiment Configuration diagram of second light receiver of the first embodiment Configuration diagram of collimating lens of the first embodiment Configuration diagram of base of Embodiment 1 (A) Configuration diagram on the upper surface side of the coupling member of the first embodiment, (b) Configuration diagram on the lower surface side Configuration diagram of laser module according to the first embodiment Configuration diagram of the objective lens driving device of the first embodiment The figure which has arrange | positioned the thermal radiation member of this Embodiment 1. (A) The perspective view which shows the fixed state of the collimating lens to the base of this Embodiment 1, (b) The sectional view which shows the fixing method of the collimating lens, (c) The cross section which shows the fixing state of the collimating lens Figure Configuration diagram of optical pickup device according to Embodiment 2 Configuration diagram of the optical system of the optical pickup device of the second embodiment (A) Top view configuration diagram of optical pickup module of Embodiment 3, (b) Bottom view configuration diagram Configuration diagram of optical disk apparatus according to Embodiment 3 Configuration diagram of optical system of conventional optical pickup device (A) Configuration diagram of conventional optical pickup device, (b) EE sectional view of (a)

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser light source 1a Light emitting element 1b Submount 1c Plate 1d Lead 1e Protection member 2 Diffraction element 2a 1st diffraction grating 2b 2nd diffraction grating 2c 1st member 2d 2nd member 2e 3rd member 2f 4th member 2g 1st transparent substrate 2h 2nd transparent substrate 2i Adhesive 2j 3rd transparent substrate 2k 4th transparent substrate 3 Beam splitter 3a Slope 3b Polarization separation film 4 Reflecting mirror 5 Collimator lens 5a Plane 6 1/4 wavelength plate 7 Wedge prism 8 Rising prism 9 Objective lens 10 Detection lens 10a Detection lens holder 11 Light receiver 11a Light receiving element 11b Light detection unit 11c, 11e Electrode 11d Wiring board 11f Light transmission unit 11g Projection electrode 11h Anisotropic conductive film (ACF)
12 dimming member 13 second light receiver 13a light receiving element 13b light detecting portion 13c, 13e electrode 13d wiring board 13f light transmitting portion 14 optical disc 14a, 14b, 14c, 14d track 15 base 15a, 15b bearing portion 15c laser module mounting portion 15d Objective lens driving device attachment portion 15e Reference surface 15f Second light receiver attachment portion 15g Reflective mirror attachment portion 15h Collimator lens attachment portion 15i Groove 15j 1/4 wavelength plate attachment portion 15k Wedge prism attachment portion 15l Rise prism attachment portion 15m Opening portion 15n Contact portion 15o Second beam splitter mounting portion 15p Through hole 15q Bearing 16 Coupling member 16a Annular portion 16b Arm portion 16c Reference surface 16d V groove 16e Space portion 16f Abutting surface 16g, 16n Through Hole 16h, 16i Convex part 16j Contact surface 16k Groove 16l Concave part 16m Wall part 17 Laser module 18 Lens holder 19 Objective lens drive device 19a Elastic support member 19b Elastic support member holder 19c Yoke 19d Focus coil 19e Tracking coil 19f Magnet 20 Optical pickup device 21, 22, 23 Condensing spots 21a, 22a, 23a Main beam 21b, 22b, 23b Sub beam 24 Heat radiation member 25 Fixing member 26 Second beam splitter 26a Separation film 29 Cover 30 Optical pickup module 31 Base 32 Spindle motor 32a Turntable 33 Feed motor 34 Screw shaft 35, 36 Guide shaft 37 Rack 38 FPC
39 Cover 40 Optical disk device 41 Housing 41a Upper housing 41b Lower housing 42 Tray 43 Bezel 44 Eject switch 45 Rail 46 External connector

Claims (26)

A laser light source that emits laser light of two types of wavelengths toward the optical disc, and the other that transmits laser light of one wavelength emitted from the laser light source, diffracts the laser light of the other wavelength, and is used for tracking control A first diffraction grating that generates a laser beam of the second wavelength and a second diffraction source that transmits the laser beam of the other wavelength, diffracts the laser beam of the one wavelength, and generates the laser beam of the one wavelength used for tracking control. A diffraction element including a diffraction grating; a light receiver that receives the laser light of the two types of wavelengths reflected by the optical disc; and a laser beam of the two types of wavelengths that is reflected by the optical disc. This is used for focus control by changing the focal length in two cross sections which are provided between the beam splitter and the beam splitter and the light receiver and are orthogonal to each other including the optical axis. Serial optical pickup apparatus characterized by comprising two kinds of the detection lens to produce a laser beam having a wavelength, a. 2. The light according to claim 1, further comprising a coupling member that holds the laser light source, the diffraction element, the light receiver, the beam splitter, and the detection lens as an integral unit and is fixed to a base. Pickup device. The laser light source includes a light emitting element that emits laser light having one wavelength and a light emitting element that emits laser light having the other wavelength, or a light emitting element that emits laser light having the two wavelengths. The optical pickup device according to claim 2, further comprising a plate for fixing a submount to be fixed, wherein the plate is fixed to the coupling member. The optical pickup device according to claim 3, further comprising a heat radiating member that connects the plate and the base. The optical pickup device according to claim 4, wherein the heat radiating member is a graphite sheet. 2. The optical pickup device according to claim 1, wherein the two types of laser beams are a laser beam for DVD and a laser beam for CD. The first diffraction grating has a first member having a predetermined refractive index, and the laser light having one wavelength has the same refractive index as the first member having the predetermined refractive index and the other wavelength. A second member having a refractive index different from that of the first member having the predetermined refractive index, and the second diffraction grating includes a third member having a predetermined refractive index; The laser light of the one wavelength has a refractive index different from that of the third member having the predetermined refractive index, and the laser light of the other wavelength is the same as the third member having the predetermined refractive index. A fourth member having a refractive index of, wherein the first member and the second member are alternately arranged in the laser light incident surface of the two types of wavelengths to form a diffraction grating, The third member and the fourth member are alternately arranged in the incident surface of the laser light having the two types of wavelengths. The diffraction grating is configured, and the second member and the fourth member each contain an organic substance having light absorption in a predetermined wavelength range, thereby forming the refractive index of the second member and the fourth member. The optical pickup device according to claim 1. 8. The optical pickup device according to claim 7, wherein the organic substances contained in the second member and the fourth member are dyes. A first transparent substrate on which the first member is disposed and a second transparent substrate on which the third member is disposed, and the surface of the first transparent substrate on which the first member is disposed and the third member are disposed. 8. The optical pickup device according to claim 7, wherein the second member, which is the same as the fourth member, is filled between the second transparent substrate and the surface of the second transparent substrate. A first transparent substrate on which the second member is disposed; and a second transparent substrate on which the fourth member is disposed. The surface of the first transparent substrate on which the second member is disposed and the fourth member are disposed. 8. The optical pickup device according to claim 7, wherein the first member, which is the same as the third member, is filled and disposed between the surface of the second transparent substrate disposed. A first transparent substrate, a second transparent substrate, and a third transparent substrate, wherein the first diffraction grating is disposed in close contact between the first transparent substrate and one surface of the second transparent substrate; 8. The optical pickup device according to claim 7, wherein the second diffraction grating is disposed in close contact between the other surface of the second transparent substrate and the third transparent substrate. A first transparent substrate, a second transparent substrate, a third transparent substrate, and a fourth transparent substrate, wherein the first diffraction grating is disposed in close contact between the first transparent substrate and the second transparent substrate; The second diffraction grating is disposed in close contact between the third transparent substrate and the fourth transparent substrate, and the first diffraction grating of either the first transparent substrate or the second transparent substrate is disposed. 8. The optical pickup device according to claim 7, wherein a surface that is not provided and a surface on which any one of the third transparent substrate and the fourth substrate is not provided with the second diffraction grating is fixed. The light receiver includes a light receiving element having a light detection unit, and a wiring board having a light transmission unit facing the light detection unit, and the laser beams of the two types of wavelengths reflected by the optical disc are the light transmission unit. The optical pickup device according to claim 1, wherein the optical pickup device is incident on the light detection unit through the light path. 14. The optical pickup device according to claim 13, wherein the light receiving element has electrodes connected to the wiring board arranged at an end thereof, and the arrangement direction of the electrodes is a direction substantially perpendicular to the optical disc. A second light receiver that receives light separated from a part of the laser light having the two types of wavelengths emitted from the laser light source and directed toward the optical disc; and the second light receiver includes a light detection unit. The optical pickup device according to claim 1, further comprising: a light receiving element; and a wiring substrate having a light transmission portion that transmits light separated from light directed to the optical disc and facing the light detection portion. 16. The optical pickup device according to claim 15, wherein the light receiving element has an electrode connected to the wiring board arranged at an end, and the arrangement direction of the electrode is a direction substantially perpendicular to the optical disc. 16. The optical pickup device according to claim 15, wherein the beam splitter separates a part of the two kinds of laser beams emitted from the laser light source from the light traveling toward the optical disc. 18. The optical pickup device according to claim 17, further comprising a light reducing member between the beam splitter and the second light receiver. 19. The optical pickup device according to claim 18, wherein the light reducing member is a light absorbing film formed on a surface of the beam splitter that faces the second light receiver. 16. The light according to claim 15, wherein the second light receiver is fixed to a coupling member that holds the laser light source, the diffraction element, the light receiver, the beam splitter, and the detection lens as an integral unit. Pickup device. 16. The optical pickup device according to claim 15, further comprising a second beam splitter that separates a part of the two kinds of laser beams emitted from the laser light source from the light directed to the optical disc. A collimating lens that has a flat surface on the side surface close to the optical disc and a side surface opposite to the side surface and that makes the laser beams of the two types of wavelengths emitted from the laser light source substantially parallel light and a fixing that fixes the collimating lens And the collimating lens is disposed on the base body side of the opening of the base so that the side surface including any one of the planes faces the opening, and the other side of the opening The optical pickup device according to claim 2, wherein a central portion of the fixing member is fixed to the flat surface facing the opening, and the fixing member is warped toward the collimating lens. A groove is provided outside the opening of the base on the side where the fixing member is disposed, and the groove and the contact portion that contacts the collimating lens of the base are light beams of the two types of wavelengths. 23. The optical pickup device according to claim 22, wherein the optical pickup device is parallel to an axis, and the groove serves as a guide at both ends of the fixing member bent. A collimating lens that makes the two types of wavelengths of laser light emitted from the laser light source substantially parallel light, and disposed between the collimating lens and the optical disc, the traveling direction of the laser light of the two types of wavelengths is determined on the optical disc. A triangular rising prism that converts the recording surface in a direction perpendicular to the recording surface; a surface that is disposed between the collimating lens and the rising prism and that faces the collimating lens; and a side that faces the rising prism The optical pickup device according to claim 1, further comprising a wedge-shaped prism whose distance from the surface is closer to the optical disc. The width of the laser light of the two types of wavelengths incident on the rising prism in the direction perpendicular to the optical disk and perpendicular to the optical axis is 1.10 times or more and 1.50 times or less when emitted from the rising prism. 25. The optical pickup device according to claim 24. A laser light source that emits laser light of two types of wavelengths toward the optical disc, and the other that transmits laser light of one wavelength emitted from the laser light source, diffracts the laser light of the other wavelength, and is used for tracking control A first diffraction grating that generates a laser beam of the second wavelength and a second diffraction source that transmits the laser beam of the other wavelength, diffracts the laser beam of the one wavelength, and generates the laser beam of the one wavelength used for tracking control. A diffraction element including a diffraction grating; a light receiver that receives the laser light of the two types of wavelengths reflected by the optical disc; and a laser beam of the two types of wavelengths that is reflected by the optical disc. This is used for focus control by changing the focal length in two cross sections which are provided between the beam splitter and the beam splitter and the light receiver and are orthogonal to each other including the optical axis. Serial optical disc apparatus, wherein a detection lens for generating a laser beam of two wavelengths, further comprising an optical pickup device provided with a.

Images