JPH1027367A - Optical pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a substrate from being heated and to prevent characteristics of a high frequency circuit on the substrate from being deteriorated and being shortened in life. SOLUTION: A laser holder 9 is provided with a rugged part for heat radiation on an outside wall part. This rugged part for heat radiation is made by forming a plurality of grooves 85 in parallel with a shaft of the holder 9 over the whole side wall of the holder 9. This rugged part for heat radiation expands a surface area and easily radiates the heat of the holder 9 off the holder 9. The heat produced by semiconductor laser 38 is conducted in the holder 9 and is, further, efficiently conducted to the frame and radiated into the air via the rugged part for heat radiation on the outside wall of the holder 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the technical field of an optical pickup device for writing and reading information signals on an optical recording medium such as an optical disk or a magneto-optical disk.

[0002]

2. Description of the Related Art Conventionally, optical recording media such as optical disks and magneto-optical disks have been proposed as recording media for information signals.
An optical pickup device for writing and reading information signals on and from such an optical recording medium has been proposed. Such an optical recording medium includes a transparent substrate made of a transparent material such as polycarbonate, and a signal recording layer formed on one main surface of the transparent substrate.

In the optical pickup device, as shown in FIG. 15, a semiconductor laser 106 serving as a light source is
The optical system includes an objective lens accommodated in the semiconductor laser 04 and receiving a light beam emitted from the semiconductor laser 106 and a photodetector as a photodetector. The semiconductor laser 106 is housed in the frame 104 while being held by a laser laser holder 105. The laser laser holder 105 is, as shown in FIG.
It is a cylindrical body formed of a metal such as brass, and the semiconductor laser 106 is fitted into the hollow portion 101. The semiconductor laser 106 is held by the laser holder 105 so that the frame 10
The positioning with respect to the position 4 can be performed accurately and easily.

The light beam emitted from the semiconductor laser 106 passes through the hollow portion 101 of the laser holder 105,
The light enters the objective lens. The light beam incident on the objective lens is condensed and irradiated on the signal recording surface of the optical recording medium by the objective lens. At this time, this light beam is irradiated onto the optical recording medium from the transparent substrate side of the optical recording medium, passes through the transparent substrate, and is condensed on the signal recording surface, which is the surface of the signal recording layer. Is done. The objective lens is supported by a biaxial actuator and is moved to constantly focus the light beam on a portion of the signal recording surface where an information signal is recorded, that is, on a recording track. This recording track is, when the optical recording medium is configured in a disk shape,
On the main surface of the optical recording medium, the optical recording medium is formed in a substantially concentric spiral shape.

In the optical recording medium, a light beam having passed through the objective lens is condensed and irradiated, so that an information signal is written at a position irradiated with the light beam.
Alternatively, reading is performed.

[0006] The luminous flux irradiated on the signal recording surface changes in light quantity, in accordance with the information signal recorded on the signal recording surface.
Alternatively, the polarization direction is modulated, reflected by the signal recording surface, and returned to the objective lens.

The light beam reflected by the signal recording surface is received by the photodetector via the objective lens. This photodetector is a light receiving element such as a photodiode, and receives a reflected light beam having passed through the objective lens and converts it into an electric signal. The information signal recorded on the optical recording medium is reproduced based on the electric signal output from the photodetector.

A focus error signal indicating a distance between a focal point of the light beam by the objective lens and the signal recording surface in an optical axis direction of the objective lens based on an electric signal output from the photodetector; And a tracking error signal indicating a radial distance of the optical recording medium between the focal point and a recording track on the signal recording surface. The biaxial actuator is controlled based on the focus error signal and the tracking error signal, and moves the objective lens so that these error signals converge to zero.

[0009]

By the way, in the above-described optical pickup device, heat generated by a semiconductor laser serving as a light source and a high-frequency circuit on a high-frequency module substrate connected to the semiconductor laser is generated by the semiconductor laser and the high-frequency wave. When the circuit is heated, the characteristics of the semiconductor laser and the high-frequency circuit are deteriorated and the life is shortened. If the characteristics of the semiconductor laser and the high-frequency circuit are degraded and the generation of noise in the semiconductor laser cannot be suppressed, good writing and reading of information signals on the optical recording medium cannot be performed.

Accordingly, the present invention has been proposed in view of the above circumstances, and prevents a semiconductor laser serving as a light source and a high-frequency module substrate connected to the semiconductor laser from being heated. It is an object of the present invention to solve the problem of providing an optical pickup device in which the characteristics of a high-frequency circuit on a substrate are prevented from being deteriorated and shortened in life.

[0011]

In order to solve the above-mentioned problems, an optical pickup device according to the present invention has a substantially cylindrical shape for housing and holding a semiconductor laser serving as a light source of a light beam for irradiating an optical recording medium. A laser holder and a frame for accommodating the laser holder are provided, and the laser holder is provided with a heat radiation uneven portion on an outer peripheral surface thereof.

In this optical pickup device, the heat generated by the semiconductor laser is transmitted through the laser holder and transmitted and released to the frame and the outside air through the heat radiating uneven portion.

According to the present invention, in the optical pickup device, the heat radiating uneven portion is constituted by a plurality of parallel grooves, and these grooves are formed over the entire outer peripheral surface of the laser holder. Are formed in a direction parallel to the axis.

In the above-mentioned optical pickup device, the heat-radiating concave and convex portion is formed by forming a plurality of parallel grooves in a direction parallel to the axis of the laser holder over the entire outer peripheral surface of the laser holder. In this case, the laser holder can be made of a so-called drawn material integrally with the heat radiation uneven portion.

[0015]

Embodiments of the present invention will be described below in the following order with reference to the drawings.

[1] Type of optical recording medium [2] Support of optical pickup device [3] Configuration of biaxial actuator (objective lens driving device) [4] Configuration in frame [5] Configuration of disc player device [1] Type of Optical Recording Medium In this embodiment, as shown in FIG. 3, the optical pickup device according to the present invention is a first type of optical recording medium in which the thickness of a transparent substrate is 0.6 mm. Writing and reading of information signals are performed by irradiating both the optical disk 101 and the second type optical disk 102 which is a disk-shaped optical recording medium having a transparent substrate thickness of 1.2 mm with a laser beam. It is configured as an optical pickup device.

The optical disk 101 of the first type includes a transparent substrate formed of a disc-shaped polycarbonate having a thickness of 0.6 mm and a diameter of 120 mm, and a signal recording layer formed on one main surface of the transparent substrate. It is configured to have. The first type optical disc 101 is a disc body having a thickness of 1.2 mm, that is, a double-sided optical disc, in which two first type optical discs 101 are bonded together on the signal recording layer side.

The first type of optical disc 101 is
The laser beam having a wavelength of 635 nm (or 650 nm) is used to write and read information signals through an objective lens having a numerical aperture (NA) of 0.6. In the signal recording layer, the information signal is recorded along a substantially concentric spirally formed recording track.

As the optical disc 101 of the first type, for example, a so-called “digital
A "video disc (DVD)" (trade name) has been proposed.

The second type optical disk 102 has a transparent substrate formed of a disc-shaped polycarbonate having a thickness of 1.2 mm, a diameter of 80 mm or 120 mm, and a signal recording layer formed on one main surface of the transparent substrate. And is configured.

The second type of optical disc 102
The information signal is written and read by a laser beam having a wavelength of 780 nm through an objective lens having a numerical aperture of 0.45. In the signal recording layer, the information signal is recorded along a substantially concentric spirally formed recording track.

Examples of such a second type of optical disk 102 include a so-called “compact disk (CD)” (trade name) and a so-called “CD-R”.
OM "and" CD-R "have been proposed.

As shown in FIG. 6, the first or second type of optical discs 101 and 102 is a rotary operation mechanism mounted on a chassis (not shown) in a disc player apparatus provided with an optical pickup device according to the present invention. Are rotated by a spindle motor 17 constituting A disk table 40 constituting a rotary operation mechanism is attached to a drive shaft 42 of the spindle motor 17. The disk table 40 is formed in a substantially disk shape, and has a substantially frustoconical projection 41 at the center of the upper surface. When the center portion of each of the optical discs 101 and 102 is placed on the disc table 40, the protrusion 41 is fitted into a chucking hole 103 provided at the center of the optical disc 101 or 102, and the optical disc 101 , 102 are held. That is, the optical disks 101 and 102
It is held on the disk table 40 and is rotated together with the disk table 40 by the spindle motor 17.

[2] Support of Optical Pickup Apparatus This optical pickup apparatus is a disc player apparatus provided with this optical pickup apparatus.
As shown in FIGS. 1 to 5, the frame 1 includes a frame 1 movably supported by a guide shaft 18 and a support shaft 19 provided on the chassis. The guide shaft 18 and the support shaft 19 are parallel to each other, and are disposed parallel to the upper surface of the disc table 40.

As shown in FIGS. 1 and 2, the frame 1 has a guide hole 1 through which the guide shaft 18 is inserted.
3, 13 and a support groove 15 into which the support shaft 19 is inserted. The inner peripheral surfaces of the guide holes 13 are formed as thrust bearings 14. The frame 1 is moved along the guide shaft 18 and the support shaft 19 so that the upper surface thereof faces the main surfaces of the optical disks 101 and 102 mounted on the disk table 40. The optical disks 101 and 102 are moved in the direction of contact and separation with the spindle motor 17, that is, in the radial direction of the optical disks 101 and 102. The frame 1 is moved by a sled motor provided on the chassis.

The bottom surface in the support groove 15 is constituted by a leaf spring 36 attached to the frame 1. A screw hole 20 is provided above the leaf spring 36 from the upper surface of the frame 1 to the inside of the support groove 15. An angle adjusting screw 11 is screwed into the screw hole 20 from above the frame 1. The angle adjusting screw 11 has a tip end on the support groove 1 according to the amount of screwing into the screw hole 20.
5, and the leading end thereof is brought into contact with the upper surface of the support shaft 19. As shown by an arrow A in FIG. 3, the frame 1 is rotated by turning the angle adjusting screw 11 to adjust the amount of screwing into the screw hole 20, thereby obtaining an arrow B in FIG.
As shown by a circle, the rotation is adjusted about the axis of the guide shaft 18 and the inclination angle with respect to the spindle motor 17 is adjusted.

[3] Configuration of Biaxial Actuator (Object Lens Driving Apparatus) The transparent substrates of the optical discs 101 and 102 are formed in a flat plate shape, but may have a slight distortion. When the part is rotated by being held by the disk table 40, a so-called surface run-out occurs. That is, the signal recording layers of the optical discs 101 and 102 periodically move in the direction of approaching and separating from the optical pickup device when the optical discs 101 and 102 are rotated while their center portions are held. The recording tracks of the optical discs 101 and 102 are as follows.
Although the center of curvature is formed so as to coincide with the center of the transparent substrate, it may have a slight eccentricity. Therefore, when the transparent substrate is rotated while its center portion is held, the optical disc 101, It moves periodically in the radial direction of 102.

In order to make a laser beam for writing and reading an information signal to and from the optical disks 101 and 102 follow the movement of the recording track due to the surface deflection or eccentricity of the optical disks 101 and 102, The pickup device is provided with first and second biaxial actuators 2 and 3 as shown in FIGS. 1 to 3 and 5. These two-axis actuators 2, 3
Is attached to the upper surface of the frame 1.

The first biaxial actuator 2 includes a first
The objective lens 4, the first objective lens 4 in the optical axis direction (i.e., the focusing direction shown by the arrow in FIG. 1 F) direction (i.e. orthogonal to and the optical axis, first shown in FIG. 1 arrow T ₁ (1 tracking direction). The first objective lens 4 has a numerical aperture of 0.6.

The second biaxial actuator 3
Means that the second objective lens 5 is moved in the direction of the optical axis of the second objective lens 5 (that is, the focus direction indicated by the arrow F in FIG. 1) and the direction perpendicular to the optical axis (that is, the arrow T in FIG. 1). _{(A second} tracking direction indicated by reference numeral 2). The second objective lens 5 has a numerical aperture of 0.45.

The objective lenses 4 and 5 correspond to the optical disks 101 and 102 mounted on the disk table 40, respectively.
And the frame 1 is connected to the guide shaft 18 and the support shaft 19.
1, 2, and 8, as shown by the arrow S in FIGS.
Is moved over the inner and outer peripheries. The first and second objective lenses 4 and 5 are arranged in a direction substantially perpendicular to the longitudinal direction of the guide shaft 18, that is, in the circumferential direction of the optical disks 101 and 102 mounted on the disk table 40. I have. The first and second objective lenses 4 and 5 are supported with their optical axes parallel to each other.

As shown in FIG. 7, each of the biaxial actuators 2 and 3 has base portions 23 and 25 fixedly disposed on the frame 1, respectively. The two-axis actuators 2, 3 are connected to the objective lenses 4,
5 has a lens bobbin main body 69 to which is attached. The lens bobbin main body 69 is formed in a frame shape from a synthetic resin material, and has an objective lens mounting hole 70 in the front end portion where the objective lenses 4 and 5 are fitted. The objective lenses 4 and 5 are fitted into and attached to the objective lens mounting hole 70 from above. The lens bobbin main body 69 has both side portions supported by the upper fixed block 59 via a pair of leaf spring members 65 and 66 serving as elastic members.

The leaf spring members 65 and 66 are integrally formed in a thin and elongated plate shape from a metal material having appropriate elasticity such as phosphor bronze. The lens bobbin body 69, the upper fixed block 59, and the leaf spring members 65, 66 are formed by so-called outsert molding.
The distal end portion and the proximal end portion of each of the leaf spring members 65 and 66 correspond to the lens bobbin main body 69 and the upper fixed block 5.
9 are connected in a state of being buried inside. The base end portions of the leaf spring members 65 and 66 protrude rearward from the rear end surface of the upper fixed block 59 as connection terminals. The distal end portions of the leaf spring members 65 and 66 are embedded in the lens bobbin main body 69, and the rear end is connected to the connection terminal 81 from the rear end surface of the lens bobbin main body 69.
And connected to a terminal plate protruding rearward.

A bobbin support frame 64 is mounted on the lower surface of the lens bobbin main body 69. The bobbin support frame 64 is formed of the same material as the lens bobbin main body 69 in a frame shape for supporting both side portions of the lens bobbin main body 69. This bobbin support frame 6
Reference numeral 4 denotes a pair of positioning projections 83, 83 projecting from the upper surface, which are positioned with respect to the lens bobbin main body 69 by the positioning projections 83, 83, and which have an adhesive to the lens bobbin main body 69. And is fixed. This bobbin support frame 64 has two side portions,
Via a pair of leaf spring members 60 and 61 serving as elastic members,
It is supported by the lower fixed block 58.

The leaf spring members 60 and 61 are integrally formed in a thin and elongated plate shape from a metal material having appropriate elasticity such as phosphor bronze. These bobbin support frames 64
And the lower fixed block 58 and the leaf spring members 6
0, 61 means that the distal end portion and the proximal end portion of each leaf spring member 60, 61 are buried inside the bobbin support frame 64 and the lower fixed block 58 by so-called outsert molding. Are linked. These leaf spring members 6
The base end portions of 0 and 61 protrude rearward from the rear end surface of the lower fixed block 58 as connection terminals. The distal ends of the leaf spring members 60 and 61 are connected to a terminal plate embedded in the bobbin support frame 64 and having a rear end protruding rearward from the rear end surface of the bobbin support frame 64 as a connection terminal 81. Has been established.

The lower fixed block 58 and the upper fixed block 59 are connected via the fixing plate 56 to the base 23,
25 fixedly disposed. That is, the lower fixing block 58 is fixed on the fixing plate 56 with an adhesive, and the upper fixing block 59 is fixed on the lower fixing block 58 with an adhesive.
Further, the fixing plate 56 is fixed to the bases 23 and 25 by bonding (or by soldering) to the bases 23 and 25 with an adhesive. The lower fixing block 5 is provided on both sides of the fixing plate 56.
Positioning protruding pieces 57 for projecting the position 8 are provided. A positioning projection 82 for positioning the upper fixed block 59 is provided on the upper surface of the lower fixed block 58.

Each of the above leaf spring members 60, 61, 65, 66
Are respectively the straight portion and the crank portions 62, 63, 6
7, 68, and the base end side is each of the fixing blocks 58,
The front end is attached to the lens bobbin main body 69 or the bobbin support frame 64. These leaf spring members 60, 61, 65,
Reference numeral 66 designates each of the linear portions substantially parallel to each other, and supports the lens bobbin body 69 and the bobbin support frame 64 so as to be displaceable with respect to the fixing portion. The crank portions 62, 63, 67, and 68 are provided on the base end portions of the leaf spring members 60, 61, 65, and 66, respectively.
It is formed to have 90 ° bent portions in opposite directions at two places. Further, these leaf spring members 60, 61, 65,
66, the crank portions 62, 63, 67, 6
A displacement restricting piece 78 is provided so as to surround both the base end side and the both sides of the halfway portion of FIG.

A coil bobbin 72 is mounted on the bobbin support frame 64 and the lens bobbin main body 69. The coil bobbin 72 is formed in the shape of a hollow quadrangular prism with the upper and lower sides open. The coil bobbin 72 is fitted into a through hole provided substantially at the center of the lens bobbin body 69 and the bobbin support frame 64, and a pair of projecting protrusions are provided on the upper surface of the bobbin support frame 64. Are fixed to the lens bobbin body 69 and the bobbin support frame 64 with an adhesive.

A focus coil 73 and tracking coils 74, 74 are mounted on the coil bobbin 72. The focus coil 73 is wound around a side surface portion (outer peripheral portion) of the coil bobbin 72, and a center axis of the coil is made parallel to an optical axis of the objective lenses 4 and 5. The tracking coils 74, 74 are wound around tracking coil bobbins 75, 75, respectively.
Is attached to the coil bobbin 72 by being attached to the front end surface of the coil bobbin 72. The tracking coils 74, 74 have their central axes parallel to each other, their central axes parallel to the linear portions of the leaf spring members 60, 61, 65, 66, and their central axes are the objective lens. The direction is orthogonal to the optical axes 4 and 5.

The lead wires at the beginning and end of winding of each of the coils 73, 74, 74 are connected to four terminal rods 80, 80, 80, 80 projecting rearward from the coil bobbin 72.
Connected corresponding to. And these terminal rods 8
0, 80, 80, 80 are the lens bobbin main body 69
The connection terminals 81, 81, 8 protruding rearward from the rear end surfaces of the lens bobbin main body portion 69 and the bobbin support frame 64 of the terminal plate embedded inside the bobbin support frame 64.
1, 81 are connected by soldering.

The lens bobbin body 69, the bobbin support frame 64, and the coil bobbin 72 constitute a lens bobbin of the biaxial actuators 2, 3.

A pair of front and rear yokes 24, 24, 26, 26 are provided on the bases 23, 25.
Standing integrally with 3, 25. These base parts 23, 25 and yokes 24, 24, 26, 26
It is formed of a magnetic material (high magnetic permeability material) such as iron. The rear yokes 24 and 26 are connected to the coil bobbin 72.
Into the inner hollow portion from below. A magnet 54 is attached to the front surfaces of the rear yokes 24 and 26 by bonding using an adhesive. The front yokes 24 and 26 are inserted from below into the through holes at the center of the bobbin support frame 64 and the lens bobbin main body 69 from the lower side, and are located on the front side of the coil bobbin 72, that is, the tracking coils 74 and 74. It is located on the front side. The upper ends of the yokes 24, 24, 26, 26 are connected to each other via a connecting plate 55. The continuous plate 55 is provided with the yokes 24, 24, 2
Magnetic material like iron (high permeability material) as in 6,26
Is formed.

In the first biaxial actuator 2, the first objective lens 4 is moved in the optical axis direction of the first objective lens 4, that is, in the focus direction indicated by an arrow F in FIGS. and a direction perpendicular to the optical axis, i.e., along which is movably supported in two directions of the first tracking direction shown in FIGS. 1 and 7 of arrow T _1, the coils 73,74,74 and It is moved in the two directions by the electromagnetic force generated between the magnets 54.

In the second biaxial actuator 3, the second objective lens 5 is arranged in the direction of the optical axis of the second objective lens 5, that is, the arrow F in FIGS.
Focus direction, and a direction orthogonal to the optical axis,
That is, the are movably supported in two directions of the second tracking direction shown in FIGS. 1 and 7 in the arrow T _2, the electromagnetic force generated between the coils 73,74,74 and the magnet 54, The moving operation is performed in the two directions.

As described above, the recording tracks are formed in the optical discs 101 and 102 in a substantially concentric spiral shape on the signal recording layer. In this optical disc, an information signal is written along the recording track. These two-axis actuators 2 and 3 move the objective lenses 4 and 5 so that the objective lenses 4 and 5 follow the displacement of the optical disks 101 and 102. That is, the optical pickup device always focuses the light beam transmitted through the objective lenses 4 and 5 on the position where the information signal is written on the signal recording layer of the optical disk.

This optical pickup device is opposed to the optical disks 101 and 102 held on the disk table 40 in the chucking holes 103 and rotated by the spindle motor 17, and in the radial direction of the optical disks 101 and 102. By performing the moving operation, the position relative to the optical discs 101 and 102 is moved along the recording track.
An information signal is written or read to or from the recording track. Therefore, in this optical pickup device, the focus position of the laser beam by the objective lenses 4 and 5 must follow the displacement of the position of the recording track due to surface deflection and eccentricity of the optical disk.
Therefore, the biaxial actuators 2 and 3 move the objective lenses 4 and 5 in the focus direction and the tracking directions.

In the biaxial actuators 2 and 3, the connection terminals protruding from the rear end surfaces of the fixed blocks 58 and 59 and the leaf spring members 60, 61, 65, 66 and the By supplying a focus drive current via each terminal board,
The lens bobbin main body 69 is moved in the focus direction as indicated by an arrow F in FIG. In these two-axis actuators 2, 3, the tracking coils 74, 74 are attached to the fixed blocks 58,
When a tracking drive current is supplied via the connection terminals protruding from the rear end face of the base plate 59, the leaf spring members 60, 61, 65, 66 and the terminal plates, the lens bobbin main body 69 is As shown by arrows T ₁ and T ₂ in FIG. 7, the moving operation is performed in each of the tracking directions.

In these two-axis actuators, the focus drive current and the tracking drive current are:
The laser beam is supplied based on an error signal (a focus error signal and a tracking error signal) indicating a shift amount between the focus position of the laser beam by the objective lenses 4 and 5 and the recording track. Therefore, the biaxial actuators 2 and 3 perform a periodic moving operation on the objective lenses 4 and 5 in synchronization with the rotation cycle of the optical disks 101 and 102.

The laser beam condensed on the signal recording layer is reflected on the signal recording layer by modulating the reflection intensity or the polarization direction in accordance with the information signal written on the signal recording layer. You. The reflected light flux reflected by this signal recording layer returns to the objective lenses 4 and 5, and
Through the objective lenses 4 and 5, the light is received by a photodetector disposed in the frame 1 as described later. This photodetector has a plurality of photodetectors. From an output signal from the photodetector, a read signal of an information signal from the optical discs 101 and 102 is obtained.
The focus error signal and the tracking error signal are generated.

Then, on the frame 1, the first biaxial actuator 2 passes through the center C of the drive shaft 42 of the spindle motor 17 to the guide shaft 18 as shown in FIGS. The center of the first objective lens 4 is located on a parallel straight line, and the first tracking direction T ₁ is arranged so as to be parallel to the guide shaft 18.

The second biaxial actuator 3
Position the center of the second objective lens 5 on a straight line parallel to the guide shaft 18 at a predetermined distance from the center C of the drive shaft 42 of the spindle motor 17, and The tracking direction T ₂ is disposed so as to form a predetermined angle θ with respect to the guide shaft 18. In the optical pickup device shown in FIGS. 1 and 2, the distance between the center C of the drive shaft 42 of the spindle motor 17 and the movement locus of the center of the second objective lens 5 is 8 mm, and the angle θ is 14 °.

[4] Structure in Frame As shown in FIG. 6, a laser coupler (a light emitting and receiving device) having a semiconductor laser 38 serving as a first light source and a semiconductor laser chip serving as a second light source is provided in the frame 1. Composite element)
33 is built in. The semiconductor laser chip of the semiconductor laser 38 and the semiconductor laser chip of the laser coupler 33 emit first and second laser beams, respectively, which are coherent lights of linear polarization. These laser beams are divergent beams. The wavelength of the first laser beam emitted from the semiconductor laser 38 is 635 nm or 650 which is the first wavelength.
nm. The wavelength of the second laser beam emitted from the semiconductor laser chip of the laser coupler 33 is the second laser beam.
780 nm, which is the wavelength of

The semiconductor laser 38 is connected to a high-frequency module substrate 37. The high-frequency module substrate 37 is provided with a semiconductor laser 38 in order to prevent the occurrence of return light noise in the semiconductor laser 38.
A high-frequency circuit driven at a high frequency of about 0 mHz to 400 MHz is provided. This high-frequency module board 37 is housed in the shield case 8.

The semiconductor laser 38 is housed in a laser laser holder 9 and disposed in the frame 1 as shown in FIG. This laser laser holder 9 is a substantially cylindrical body formed of a metal such as brass, and as shown in FIGS.
The semiconductor laser 38 is fitted therein. This proximal hollow portion 87 is
It is continuous with the distal end hollow portion 86 having an inner diameter smaller than that. The first laser light emitted from the semiconductor laser 38 is emitted from the inside of the base end hollow portion 87 to the tip end side of the laser holder 9 via the inside of the tip end hollow portion 86. The distal end of the laser holder 9 has a tapered portion 90 with a tapered distal end and a sharp distal end.

The laser holder 9 is provided with a heat radiating uneven portion on the outer peripheral surface. The heat radiating uneven portion is formed by forming a plurality of parallel grooves 85 in a direction parallel to the axis of the laser holder 9 over the entire outer peripheral surface of the laser holder 9. The surface area of the heat-releasing concavo-convex portion formed by the formation of the plurality of grooves 85 is increased, and the heat of the laser holder 9 is easily released to the outside of the laser holder 9. I have.

That is, in this optical pickup device, the heat generated by the semiconductor laser 38 is transmitted through the laser holder 9 and passes through the heat radiating projections and depressions on the outer peripheral surface of the laser holder 9 so that the frame 1 and the It is efficiently conducted and released into the outside air.

In the laser holder 9, the heat radiating projections and depressions are formed over the entire outer peripheral surface of the laser holder 9 by forming a plurality of parallel grooves 85 in a direction parallel to the axis of the laser holder 9. In this case, a so-called drawing material can be integrally formed with the heat-radiating concave and convex portion, and can be easily manufactured.

The outer surface (upper surface) of the frame 1
The position corresponding to the storage position of the laser holder 9 is a heat radiating section 10. This heat radiation part 1
No. 0 is such that the surface area is increased by forming a plurality of parallel grooves, the heat radiation efficiency to the outside air is improved, and the heat generated by the high-frequency module substrate 37 and the semiconductor laser 38 is radiated outward. Has been made.

Each groove constituting the heat radiating section 10 is
It is formed in a direction substantially orthogonal to the direction from the shield case 8 that houses the high-frequency module substrate 37 connected to the semiconductor laser 38 to the heat radiation unit 10.
Therefore, in this optical pickup device, the air heated in the heat radiating section 10 is
Of the high-frequency module substrate 37 is prevented from flowing along the respective grooves constituting the above, and flowing toward the shield case 8 side.

In the laser holder 9, each of the grooves forming the heat radiating concave and convex portions is, as shown in FIGS. 11 and 12, a groove 88 formed in the circumferential direction of the outer peripheral surface of the laser holder 9. Is also good. In addition, the laser holder 9
As shown in FIGS. 13 and 14, a plurality of fins (thin plate members) 89 are integrally provided on the outer peripheral surface of the laser holder 9 to increase the surface area. It may be. In any of these cases, the surface area of the heat radiating uneven portion is increased, and the heat of the laser holder 9 is easily released to the outside of the laser holder 9. In the case where the heat radiation uneven portion is constituted by a plurality of fins 89 erected on the outer peripheral surface of the laser holder 9, the frame 1 has openings for allowing the fins 89 to face outward. Section is provided.

In the frame 1, the first laser beam emitted from the semiconductor laser 38 passes through a grating (diffraction grating) 39 attached to the tip of the laser laser holder 9, and passes through a flat beam splitter. 28. The grating 39 is formed by the first
Is split into three laser light beams of zero-order light and ± first-order light. The beam splitter 28 is disposed such that its main surface is at an angle of 45 ° with respect to the optical axis of the first laser beam. This beam splitter 28
A part of the first laser beam is transmitted, but the rest is reflected. The first laser beam reflected by the beam splitter 28 enters a collimator lens 29,
The collimator lens 29 forms a first parallel laser beam.

The first parallel laser beam having passed through the collimator lens 29 is emitted to the outside of the frame 1 through the first through hole 6 provided on the upper surface of the frame 1. Then, the first parallel laser beam is incident on the first objective lens 4. The first objective lens 4 focuses the first parallel laser beam on the signal recording layer of the first type optical disc 101.

The laser coupler 33 has a configuration in which the semiconductor laser chip and the first and second photodetectors are disposed on the same semiconductor base. The semiconductor laser chip is disposed on the semiconductor base via a heat sink. Each of the photodetectors is formed on the semiconductor base in a state of being divided into a plurality of light receiving surfaces.

In the laser coupler 33, a beam splitter prism is disposed on each of the photodetectors. The beam splitter prism has a beam splitter surface, which is a slope portion having a predetermined inclination angle with respect to an upper surface portion of the semiconductor base member, directed toward the semiconductor laser chip.

In the laser coupler 33, the semiconductor laser chip emits the second laser beam toward the beam splitter surface. The second laser beam emitted from the semiconductor laser chip is reflected by the beam splitter surface and emitted vertically upward with respect to the semiconductor base.

The second laser beam emitted from the laser coupler 33 is reflected by the rising mirror 34,
The light is emitted to the outside of the frame 1 through a second through hole 7 provided in the upper surface of the frame 1. And
The second parallel laser beam is supplied to the second objective lens 5.
Is incident on. The second laser beam that has entered the second objective lens 5 passes through the transparent substrate of the second type optical disk 102 by the second objective lens 5 and passes through the transparent substrate of the second type optical disk 102. The light is focused on the surface of the signal recording layer.

A skew sensor 12 is mounted on the upper surface of the frame 1. The skew sensor 12 includes a light emitting element such as an LED and a plurality of light receiving elements such as a photodiode. The skew sensor 12 transmits the light emitted from the light emitting element to the optical disc 10 mounted on the disc table 40.
Irradiate the optical discs 101 and 1 with this light.
02 by detecting the position (intensity distribution) of the light reflected by the optical discs 101 and 10 by the light receiving element.
2 (skew) can be detected.

[5] Configuration of Disc Player In the above disc player, the detection output obtained by the skew sensor 12 is sent to a control circuit (not shown). A signal output from the optical pickup device is sent to the control circuit. The control circuit controls the pickup device, the spindle motor 17 and the sled motor according to various signals transmitted. That is, the control circuit controls the driving of the biaxial actuators 2 and 3 in the optical pickup device, and the emission and extinction of the semiconductor laser 38 and the semiconductor laser chip. Further, the control circuit controls the rotational drive of the spindle motor 17 and the sled motor.

When it is determined that the first type of optical disk 101 is mounted on the disk table 40, the control circuit causes the semiconductor laser 38 to emit light and the semiconductor laser chip To extinguish At this time, the first laser beam that has passed through the first objective lens 4 is irradiated onto the first type optical disc 101 from the transparent substrate side of the first type optical disc 101 and passes through the transparent substrate. Thus, the light is focused on the signal recording layer. The first objective lens 4 is moved by the first biaxial actuator 2 in the optical axis direction of the first objective lens 4 and in a direction orthogonal to the optical axis. The first objective lens 4 is connected to the first biaxial actuator 2
Accordingly, the first type of optical disc 101 is moved following the displacement of the first objective lens 4 in the direction of the optical axis (so-called surface deflection), so that the focal point of the laser beam is always adjusted. It is located on the signal recording layer. Further, the first objective lens 4 follows the displacement of the recording track of the first type optical disc 101 in the direction orthogonal to the optical axis of the first objective lens 4 by the first biaxial actuator 2. Then, the focusing point of the first laser beam is always positioned on the recording track.

This optical pickup device converges and irradiates the first laser beam onto the signal recording layer of the first type optical disc 101 to write and read information signals to and from this signal recording layer. Do. In writing the information signal, when the first type optical disk 101 is a magneto-optical disk, the magneto-optical disk is irradiated with the first laser beam and the first laser beam is An external magnetic field is applied to the irradiation position. By modulating either the optical output of the first laser beam or the intensity of the external magnetic field according to the information signal to be recorded, the information signal is written to the magneto-optical disk. When the first type optical disk 101 is a phase change type disk,
By modulating the optical output of the first laser beam according to the information signal to be recorded, the information signal is written to the phase change disk.

In this optical pickup device, the first laser beam is condensed and irradiated on the signal recording layer of the first type optical disc 101, and the laser beam reflected by the signal recording layer is reflected by the first laser beam. , The information signal is read from the signal recording layer.

In the reading of the information signal, when the first type optical disk 101 is a magneto-optical disk, the change in the polarization direction of the reflected light beam is detected to detect the information signal from the magneto-optical disk. Reading is performed. When the first type of optical disk 101 is a phase change disk or a so-called pit disk, a change in the amount of reflected light of the reflected light beam is detected to detect an information signal from the phase change disk. Reading is performed.

That is, the first laser beam condensed on the signal recording layer is reflected by the signal recording layer, and returns to the first objective lens 4 as a reflected beam.
The reflected light flux returning to the first objective lens 4
A parallel light beam is formed by the objective lens 4 and returns to the beam splitter 28 via the collimator lens 29. The reflected light flux returning to the beam splitter 28 is transmitted through the beam splitter 28, is branched to an optical path returning to the semiconductor laser 38, and is split into a photodetector (OEI).
C) Go to 32.

Since the beam splitter 28 is a parallel flat plate inclined at an angle of 45 ° with respect to the optical axis of the reflected light beam, it generates astigmatism in the reflected light beam. When the first type optical disk 101 is a magneto-optical disk, the reflected light beam having passed through the beam splitter 28 enters the photodetector (OEIC) 32 through a Wollaston prism. The Wollaston prism converts the reflected light beam into a first polarized light component that is polarized in the polarization direction of the reflected light beam and a second polarized light component that is polarized in a direction of + 45 ° with respect to the polarization direction of the reflected light beam. And a third polarized light component that is polarized in a direction of −45 ° with respect to the polarization direction of the reflected light flux.

The photodetector (OEIC) 32 includes a plurality of photodiodes corresponding to the plurality of light beams branched by the grating 39 and the Wollaston prism, and the light beams correspond to the respective light beams. The light is received by the photodiode. By arithmetically processing the light detection output from each photodiode of the photodetector (OEIC) 32, a read signal, a focus error signal, and a tracking error signal of an information signal recorded on the magneto-optical disk are generated. The focus error signal is generated between the focal point of the first laser beam by the first objective lens 4 and the surface of the signal recording layer of the first type optical disc 101.
This is a signal indicating the amount and direction of displacement of the first objective lens 4 in the optical axis direction. The tracking error signal is
The displacement of the focal point of the first laser beam by the first objective lens 4 and the recording track of the first type optical disc 101 in the direction orthogonal to the optical axis of the first objective lens 4 It is a signal indicating the amount and direction. The first biaxial actuator 2 is driven based on the focus error signal and the tracking error signal.

In the photodetector (OEIC) 32,
The photodiode for receiving the reflected light of the 0th-order light of the first laser light from the signal recording layer has four light receiving surfaces arranged radially around the optical axis of the reflected light. Have been. The beam spot formed on the light receiving surfaces of the four photodiodes by the reflected light beam is an elliptical beam spot whose major axis direction is a direction corresponding to the direction of astigmatism generated by the beam splitter 28. Become. Here, assuming that the light detection outputs from the four light receiving surfaces are a, b, c, and d, respectively, Fe = (a + c)-(b + d) indicates the direction and amount of astigmatism of the reflected light flux. Signal. This Fe is a focus error signal, and is a signal indicating the distance and direction between the focal point of the first laser beam by the first objective lens 4 and the signal recording surface of the first type optical disc 101. It has become.

The first two-axis actuator 2 is driven based on the focus error signal Fe to move the first objective lens 4 so as to move the first objective lens 4.
A focus servo operation is performed in which the focal point of the first laser beam by the objective lens 4 is always positioned on the signal recording surface.

In the photodetector (OEIC) 32, the photodiodes for receiving the reflected light beams of the first laser light beam ± first-order light from the signal recording layer are two light-receiving surfaces independent of each other. Is configured.
The amount of reflected light of the ± first-order light becomes equal to each other when the condensing point of the first-order light of the first laser light by the first objective lens 4 is on the recording track. Here, assuming that the light detection outputs from the two light receiving surfaces are e and f, respectively, Te = ef is a signal indicating the difference in the amount of reflected light of the ± primary light. This Te is a tracking error signal, and the focal point of the 0th-order light of the first laser beam by the first objective lens 4 and the first type optical disc 101
This signal indicates the distance and direction from the recording track.

The first biaxial actuator 2 is driven on the basis of the tracking error signal Te to move the first objective lens 4, thereby causing the first objective lens 4 to move the first objective lens 4. A tracking servo operation is performed in which the focal point of the zero-order light of the laser beam is always positioned on the recording track.

The optical pickup device is moved along the guide shaft 18 and the support shaft 19, so that the first objective lens 4 is moved.
Is operated so as to face the entire area of the signal recording area of the first type optical disc 101,
Information signals can be written and read for the entire signal recording area. That is, the optical pickup device is moved along the inner and outer peripheries of the first type optical disk 101, and is rotated by the first type optical disk 101, whereby the first type optical disk 101 is rotated. Information signals can be written and read for the entire signal recording area.

In this optical pickup device, the detection of the tracking error signal for the first type optical disk 101 is performed by the so-called three-beam method as described above. Therefore,
In this optical pickup device, as shown in FIG. 2, the first objective lens 4 is located at the center of the first type optical disk 101 (that is, the disk table 4).
0 of the first type optical disc 101 while maintaining a state opposing a straight line passing through the center of the first type optical disc 101 (ie, a state where the optical axis intersects a straight line passing through the center of the first type optical disc 101).
The moving operation is performed over the inner and outer peripheries of 01.

The tracking error signal of the first laser beam may be detected by a so-called one-beam method. In this case, the grating 39 is not provided. The tracking error signal can be detected by employing a so-called push-pull method, a phase difference method (including a so-called V-DPD method), a wobbling method, or the like. In this case, as described above, the first objective lens 4 does not need to maintain a state facing the straight line passing through the center of the first type optical disc 101 when the frame 1 is moved. Absent.

When the control circuit 32 determines that the second type optical disk 102 is mounted on the disk table 40, the control circuit 32 causes the semiconductor laser chip to emit light and the semiconductor laser chip to emit light. 38 is extinguished. At this time, the second through the second objective lens 5
Is irradiated onto the second type optical disc 102 from the transparent substrate side of the second type optical disc 102, passes through the transparent substrate, and is focused on the signal recording layer. The second objective lens 5 is moved by the second biaxial actuator 3 in the optical axis direction of the second objective lens 5 and in a direction orthogonal to the optical axis. The second objective lens 5 is moved by the second biaxial actuator 3 to the second type of the optical disc 101 of the second type.
Of the objective lens 5 in the optical axis direction (so-called surface runout)
The focal point of the second laser beam is always positioned on the signal recording layer by the moving operation. Further, the second objective lens 5 is displaced by the second biaxial actuator 3 in the displacement of the recording track of the second type optical disc 102 in a direction orthogonal to the optical axis of the second objective lens 5. By following the movement operation, the focal point of the second laser beam is always positioned on the recording track.

This optical pickup device reads out an information signal from the signal recording layer by condensing and irradiating the second laser beam onto the signal recording layer of the second type optical disc 102. . That is, in this optical pickup device, the second laser beam is condensed and irradiated on the signal recording layer of the second type optical disc 102, and the second laser beam is reflected by the signal recording layer. , The information signal is read from the signal recording layer. The reading of this information signal is performed by detecting a change in the amount of reflected light of the reflected light flux.

That is, the second laser beam focused on the surface of the signal recording layer is reflected by the signal recording layer and returns to the second objective lens 5. The reflected light flux returned to the second objective lens 5 is transmitted to the rising mirror 3
After 4, the beam returns to the beam splitter surface in the laser coupler 33.

The reflected light flux returning to the beam splitter surface is transmitted through the beam splitter surface and enters the beam splitter prism, whereby it is branched from the optical path returning to the semiconductor laser chip, and the first light detection Is received by the detector. Also, the reflected light flux is the first light beam.
The light is reflected by the surface of the photodetector and the inner surface of the beam splitter prism, and is also received by the second photodetector.

A read signal (RF signal) of an information signal recorded on the second type of optical disc 102 based on the light detection output output from each of the photodetectors, (2) a focus error signal Fe indicating a shift (focus error) in the optical axis direction between the focal point of the laser beam and the surface of the signal recording layer; and a focus error signal Fe formed at the focal point and the surface of the signal recording layer. A tracking error signal Te indicating a deviation (tracking error) of the optical axis and the direction perpendicular to the recording track from the recording track thus calculated is calculated.

That is, the read signal (RF signal)
Is obtained as the sum of the respective light detection outputs of the respective photodetectors. Further, the focus error signal Fe is obtained as a difference between the respective light detection outputs of the respective light detectors.

Further, the tracking error signal Te
Is the sum of the light detection output (A) from the light receiving surface on one side of the first photodetector and the light detection output (D) from the light receiving surface on the other side of the second photodetector. The light detection output (B) from the light receiving surface on the other side of the first photodetector and the sum of the light detection output (C) from the light receiving surface on the one side of the second photodetector. Obtained as the difference ((A + D)-(B + C)).

In each of the photodetectors, the dividing line between the light receiving surface on one side and the light receiving surface on the other side is at an angle of 45 ° with respect to the tangential direction of the recording track on the second type optical disc 102. The angle is made.

That is, in this optical pickup device, the optical disk 102 of the second type is
The tracking error signal is detected by a so-called push-pull method of a so-called one-beam method.

The optical pickup device is moved along the guide shaft 18 and the support shaft 19 so that the second objective lens 5 is moved to the signal recording area of the second type optical disc 102. The information signal can be read over the entire area of the signal recording area by performing the moving operation so as to face the entire area. That is, the optical pickup device is moved along the inner and outer peripheries of the second type optical disk 102, and the second type optical disk 102 is rotated to operate the optical pickup device. An information signal can be read from the entire signal recording area.

In the disc player device, the thickness of the transparent substrate of the optical discs 101 and 102 mounted on the disc table 40 is detected based on the amplitude of the RF signal read from the optical discs 101 and 102. It can be determined by the control circuit. That is, the first and second types of optical discs 10
When any one of the first and second light sources is mounted on the disk table 40, one of the first and second light sources is emitted. At this time, if only the focus servo is operated, the amplitude of the RF signal can be detected, and which of the first and second light sources emits light can be detected. Based on the amplitude of the RF signal thus determined, it can be determined which of the first and second types of optical disks 101 and 102 is mounted on the disk table 40.

[0094]

As described above, in the optical pickup device according to the present invention, the outer peripheral surface of the substantially cylindrical laser holder that stores and holds the semiconductor laser that is the light source of the light beam for irradiating the optical recording medium is provided. And a heat radiation uneven portion.

Therefore, in this optical pickup device, the heat generated by the semiconductor laser is transmitted through the laser holder and transmitted to the frame accommodating the laser holder and the outside air through the heat radiating irregularities. Released.

That is, in the present invention, the semiconductor laser serving as the light source and the high-frequency module substrate connected to the semiconductor laser are prevented from being heated, and the characteristics of the semiconductor laser and the high-frequency circuit on the high-frequency module substrate are deteriorated and the life is shortened. It is possible to provide a prevented optical pickup device.

Further, in the optical pickup device according to the present invention, the heat radiating concave and convex portions are formed with a plurality of parallel grooves extending in a direction parallel to the axis of the laser holder over the entire outer peripheral surface of the laser holder. In this case, the laser holder is integrated with the heat-radiating irregularities,
It can be made of a so-called drawn material and can be easily manufactured.

[Brief description of the drawings]

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

FIG. 2 is a plan view showing a configuration of the optical pickup device.

FIG. 3 is a front view showing a configuration of the optical pickup device.

FIG. 4 is a bottom view showing the configuration of the optical pickup device.

FIG. 5 is an exploded perspective view showing a configuration of the optical pickup device.

FIG. 6 is a perspective view showing a configuration of an optical system in the optical pickup device.

FIG. 7 is an exploded perspective view showing a configuration of a biaxial actuator provided in the optical pickup device.

FIG. 8 is a perspective view showing a configuration of a laser holder and a semiconductor laser of the optical pickup device.

FIG. 9 is a front view showing a configuration of the laser holder.

FIG. 10 is a longitudinal sectional view showing a configuration of the laser holder.

FIG. 11 is a perspective view showing another example of the configuration of the laser holder of the optical pickup device according to the present invention.

FIG. 12 is a longitudinal sectional view showing a configuration of the laser holder shown in FIG. 11;

FIG. 13 is a perspective view showing still another example of the configuration of the laser holder of the optical pickup device according to the present invention.

FIG. 14 is a front view showing the configuration of the laser holder shown in FIG. 13;

FIG. 15 is a plan view and a side view showing a configuration around a semiconductor laser in a conventional optical pickup device.
It is.

FIG. 16 is a perspective view showing a configuration of a laser holder and a semiconductor laser of a conventional optical pickup device.

[Explanation of symbols]

1 frame, 9 laser holder, 38 semiconductor laser, 85, 88 heat dissipation groove, 89 heat dissipation fin

Claims (2)

[Claims] 1. A substantially cylindrical laser holder for storing and holding a semiconductor laser serving as a light source of a light beam for irradiating an optical recording medium, and a frame for storing the laser holder, wherein an outer peripheral surface of the laser holder is provided. Optical pickup device provided with a heat radiation uneven portion. 2. The heat radiation uneven portion is constituted by a plurality of parallel grooves, and these grooves are formed in the direction parallel to the axis of the laser holder over the entire outer peripheral surface of the laser holder. The optical pickup device according to claim 1.