JPH1049896A - Optical pickup and optical disk device - Google Patents

Abstract

(57) [PROBLEMS] To provide a small and lightweight optical base with a simple configuration and to easily connect a glass epoxy substrate mounted on the surface of the optical base to ground, and an optical pickup therefor. To provide an optical disk device using a computer. SOLUTION: In an optical pickup 30, a convex portion 31c having the same height as a glass epoxy substrate 31b is formed on a sheet metal base 31a, and the glass epoxy substrate is grounded corresponding to the convex portion. A hole 31d having a connection land 31e is provided. At the time of assembly, the ground connection land 31e is soldered to the convex portion 31c fitted in the hole 31d.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup for recording and / or reproducing signals from an optical disk such as an optical disk, a magneto-optical disk, and a phase change type disk, and an optical disk device provided with the optical pickup. Things.

[0002]

2. Description of the Related Art Conventionally, an optical pickup for an optical disk is constructed, for example, as shown in FIG. In FIG. 6, an optical pickup 1 includes a grating 3, a beam splitter 4, a collimator lens 5, an objective lens 6, and a beam, which are sequentially arranged in the optical path of a light beam emitted from a semiconductor laser element 2 as a light source. And a photodetector 7 disposed in a separation optical path of return light from the optical disc D that has passed through the splitter 4.

In the optical pickup 1 having such a configuration, the light beam from the semiconductor laser device 2 is split into a plurality of light beams by a grating 3, reflected by a beam splitter 4, and then collimated by a grating 5. And irradiates the signal recording surface of the optical disc D with the objective lens 6. The return light beam reflected by the signal recording surface passes through the beam splitter 4 from the objective lens 6 and the collimator lens 5 and is received by the light receiving surface of the photodetector 7 so that the recording signal is detected. It has become.

Here, the objective lens 6 is supported by a biaxial actuator 10 having, for example, a configuration shown in FIG. 7 so as to be movable in two axial directions, that is, in a focus direction and a tracking direction. In FIG. 7, the biaxial actuator 10
The biaxial actuator 10 is made of a lens holder 12 to which an objective lens 11 is attached, a coil bobbin 13 attached to the lens holder 12 by bonding or the like, and an elastic material which supports the lens holder 12 at one end. The vehicle includes a suspension 14 and a mounting member 16 for fixing and holding the other end of the suspension 14 to a fixed side such as the base 15.

One end of each of two parallel suspensions 14 is attached to each side of the lens holder 12. Further, the other end of the suspension 14 is fixedly held to the mounting member 16. As a result, the lens holder 12 is movably supported in two directions perpendicular to the base 15, that is, in a tracking direction indicated by reference numeral Trk and a focusing direction indicated by reference numeral Fcs.

A coil 13a for focusing and a coil 13b for tracking are wound around the coil bobbin 13. On the other hand, the ends 17a and 17b of the yoke 17 attached to the base 15 are connected to the coils 13a and 13b, respectively.
A magnet 18 is attached to the inner surface of one end 17a of the yoke 17 on the fixed portion side. The upper side of the coil bobbin 13 (in the drawing, the objective lens 11 side) has the metal cover 1.
9. The cover 19 connects the upper ends of the ends 17a and 17b of the yoke to form a closed magnetic circuit.

[0007] The biaxial actuator 10 having such a configuration
According to the method described above, when a drive current is applied to each of the coils 13a and 13b, the magnetic field generated in each of the coils 13a or 13b interacts with the magnetic field generated by the yoke 17 and the magnet 18, thereby causing the lens holder 12 and the objective lens 11 to rotate. Is moved and adjusted in two axial directions.

Thus, for accurate detection of a reproduced signal, the light beam from the semiconductor laser element 2 is applied to the optical disk D.
Thus, a spot is formed at a correct position on the signal recording surface of the recording medium, and an accurate reproduction of the recording signal is performed. The objective lens 6 is finely adjusted in the biaxial directions by the biaxial actuator 10 based on a predetermined servo signal. The servo of the objective lens 6 includes a tracking servo for finely moving the objective lens 6 along a radial direction of the optical disc D with respect to a recording track of the optical disc D;
Focusing servo is performed to finely move the objective lens 6 in a direction to approach and separate from the signal recording surface of the optical disc D along the optical axis.

[0009]

By the way, in the optical pickup 1 having such a configuration, the base portion 15
Is fixedly held with respect to an optical base (not shown) of the optical pickup 1 in a skew-adjusted state.
The optical base includes coils 13a and 13a for focusing and tracking of the biaxial actuator 10.
Due to the interaction of the magnetic field generated between b and the yoke 17, the vibration of the yoke 17 is transmitted. For this reason, the optical base is made of a highly rigid material such as aluminum / zinc die-cast to suppress the vibration of the yoke 17. Therefore, the optical base is
There is a problem that the material becomes relatively large and heavy, and the material cost is high.

On the other hand, an optical base (sheet metal base) formed of sheet metal is also conceivable. In the case of the sheet metal base, a substrate on which the semiconductor laser element 2 as a light source and the photodetector 7 are to be mounted is provided on the upper surface thereof. Is mounted, it is difficult to connect the substrate and the sheet metal base to ground. In particular, in the case of an optical pickup in which a light emitting and receiving device in which the semiconductor laser element 2 and the photodetector 7 are integrally formed is mounted on a substrate, the lower surface of the photodetector 7 is grounded depending on the frequency of a signal to be used. Therefore, a sheet metal base that is advantageous in terms of such cost cannot be used.

In view of the above, the present invention provides an optical pickup in which a small and lightweight optical base is obtained, and a substrate mounted on the surface is easily grounded. It is intended to provide an optical disk device.

[0012]

According to the present invention, there is provided a light source for emitting a light beam, and a light beam for focusing the light beam emitted from the light source on a signal recording surface of a rotationally driven optical disk. A photodetector having a focusing means, a light separating means disposed between the light source and the light focusing means, and a light receiving portion for receiving a return light beam from a signal recording surface of the optical disc separated by the light separating means. And an optical base for supporting the light source, the light separating means and the photodetector,
The optical base includes a conductive metal base and a substrate on which a light source and a photodetector mounted thereon are mounted.
A convex portion having the same height as the substrate is formed on the metal base, and the substrate has a hole having a connection land formed corresponding to the convex portion. Is done.

According to the above configuration, the substrate on which the photodetector and the like are mounted is placed on the conductive metal base constituting the optical base, and the ground connection land formed on the substrate is mounted on the substrate. Is fitted in the projection formed on the metal base. Then, they are electrically connected by soldering. As a result, the substrate is grounded to the metal base by the projections to which the connection lands are soldered.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS. still,
Since the embodiments described below are preferred specific examples of the present invention, various technically preferred limitations are added.
The scope of the present invention is not limited to these embodiments unless otherwise specified in the following description.

FIG. 1 shows an embodiment of an optical disk device incorporating an optical pickup according to the present invention.
In FIG. 1, an optical disk device 20 includes an optical disk 21
Spindle motor 22 as a driving means for rotationally driving the motor
And an optical pickup 30 for irradiating a signal recording surface of the rotating optical disk 21 with a light beam to record a signal and reproducing a recorded signal by a return light beam from the signal recording surface, and a control unit 23 for controlling these. It has. Here, the control unit 23 includes an optical disk controller 24, a signal demodulator 25, an error correction circuit 26, an interface 2
7, a head access control unit 28 and a servo circuit 29 are provided.

The optical disk controller 24 controls the drive of the spindle motor 22 at a predetermined rotation speed. The signal demodulator 25 demodulates the recording signal from the optical pickup 30 to correct the error, and sends the demodulated signal to an external computer or the like via the interface 27. This allows an external computer or the like to receive a signal recorded on the optical disk 21 as a reproduction signal.

The head access control unit 28 moves the optical pickup 30 to a predetermined recording track on the optical disk 21, for example, by a track jump or the like. At the moved predetermined position, the servo circuit 29 moves the objective lens held by the biaxial actuator of the optical pickup 30 in the focusing direction and the tracking direction.

FIG. 2 shows an optical pickup incorporated in the optical disk device 20. In FIG.
The optical pickup 30 includes a light receiving / emitting device 32 (see FIG. 3), which is integrally provided with a semiconductor laser element as a laser light source and a photodetector, respectively disposed on an optical base 31, and a light path bending mirror. A light emitting unit cover 33 having a reflecting surface 33a, a prism mirror 34 as a rising mirror, and an objective lens 35 as a light focusing means
And a biaxial actuator 36 for moving the objective lens 35 in the biaxial directions.

Here, the optical elements other than the objective lens 35, that is, the light receiving / emitting device 32, the light emitting unit cover 33, and the prism mirror 34 are optically supported movably in the radial direction of the optical disk 11 by means not shown. Base 31
The upper part is fixedly held.

Here, the light emitting / receiving device 32 is configured, for example, as shown in FIG. In FIG. 3, a light emitting / receiving device 32 includes a second semiconductor substrate 32b for light output mounted on a first semiconductor substrate 32a, and a semiconductor laser element 32 as a light emitting element on the second semiconductor substrate 32b.
c is mounted. On the first semiconductor substrate 32a in front of the semiconductor laser device 32c, a microprism 32d having a trapezoidal longitudinal section is provided with the inclined surface 32e as a semi-transmissive surface facing the semiconductor laser device 32c. .

Here, the micro prism 32d is
A semi-permeable film (not shown) is formed on the inclined surface 32e. Thereby, the light beam emitted from the semiconductor laser element 32c along the surface of the second semiconductor substrate 32b is reflected by the inclined surface of the microprism 32d,
The light travels upward and reaches the optical disk 21 via the reflection surface 33a of the light emitting unit cover 33, the prism mirror 34, and the objective lens 35 described above. The return light from the signal recording surface of the optical disc 11 is
5, the inclined surface 32 of the microprism 32d via the prism mirror 34 and the reflecting surface 33a of the light emitting unit cover 33.
e and reaches the bottom surface of the microprism 32d. The return light that has reached the bottom surface of the microprism 32d partially transmits through the bottom surface, and is partially reflected by the bottom surface, and travels toward the top surface of the microprism 32d.

Here, a first photodetector 32f is formed on the first semiconductor substrate 32a below the return light incident position of the microprism 32d. The return light reflected on the bottom surface is reflected on the top surface of the microprism 32d, and is incident on the bottom surface of the microprism 32d again. A second photodetector 32g is formed on the first semiconductor substrate 32a below the bottom surface of the microprism 32d where the return light reflected by the upper surface of the microprism 32d enters.

The first photodetector 32f and the second photodetector 32g are each divided into a plurality of light receiving sections.
The detection signal of each light receiving section is output independently. Note that a third photodetector 32h is provided on the second semiconductor substrate 32b on the side opposite to the emission side of the semiconductor laser element 32c. This third photodetector 3
2h is for monitoring the emission intensity of the semiconductor laser element 32c.

The semiconductor laser element 32c is a light-emitting element utilizing recombination light emission of a semiconductor, and is used as a laser light source.

The light emitting section cover 33 is
After the laser light beam going upward from 2c enters the light emitting unit cover 33, the reflection surface 33 formed on the surface thereof
The light is internally reflected by a, travels substantially horizontally again in the light-emitting unit cover 33, and exits from the light-emitting unit cover 33, and is configured as a so-called internal reflection type optical path bending mirror. Here, the light emitting unit cover 33 is formed of a transparent resin capable of transmitting a laser light beam from the semiconductor laser element 32c, and is mounted at a predetermined position on the optical base 31 so that the reflection surface 33a is formed. Are positioned at predetermined positions.

The prism mirror 34 is a mirror disposed at an angle of 45 degrees on the optical base 31 and reflects a light beam traveling in a substantially horizontal direction from the light emitting unit cover 33 upward in the vertical direction. It has become.

The objective lens 35 is a convex lens and focuses the light from the prism mirror 34 on a desired track on the signal recording surface of the optical disk 11 which is driven to rotate.

Here, the objective lens 35 is supported by a biaxial actuator 36 shown in FIG. 2 so as to be movable in a biaxial direction, that is, a focusing direction and a tracking direction. The biaxial actuator 36 is attached to the fixed portion 3 attached to the optical base 31 in a skew-adjusted state.
6a, a movable part 36c movably supported in two axial directions by two pairs of left and right elastic support members 36b parallel to the fixed part 36a, a focusing coil 36d attached to the movable part 36c, and tracking. Coil 36
e.

On the other hand, a yoke 36f is provided on the optical base 31 so as to face the focusing coil 36d and the tracking coil 36e, and a magnet 36 mounted inside the yoke 36f.
g is provided.

Thus, when a drive current flows through the focusing coil 36d, the focusing coil 36d
Magnetic field generated by the magnet 36g and the yoke 36f
The movable portion 36c is driven in the focus direction by the interaction with the magnetic flux flowing through the movable portion 36c. When a drive current flows through the tracking coil 36e, the magnetic field generated in the tracking coil 36e interacts with the magnetic flux flowing through the magnet 36g and the yoke 36f, so that the movable portion 36c is driven in the tracking direction. Thus,
The objective lens 35 held by the movable portion 36c is driven and controlled in the biaxial directions.

As shown in FIGS. 4 and 5, the optical base 31 comprises, for example, a metal base 31a and a substrate 31b mounted thereon. The metal base 31a is made of a conductive metal, for example, iron, is formed by sheet metal working, and has a convex portion 31c protruding upward near the center thereof. This convex portion 31c
For example, as shown in FIG.
It is a half blanking dowel formed at the same time.

The substrate 31b is, for example, a glass epoxy substrate, and the height of the convex portion (half blanking dowel) 31c of the sheet metal base 31a is selected to be substantially the same as that of the glass epoxy substrate 31b. The metal base 31a is
The material is not limited to iron, and other materials having sufficient strength and conductivity can be used. The protrusion 31c of the sheet metal base 31a is
The protrusion is not limited to the half blanking dowel, and may be a protrusion having any configuration made of a conductive material such as a dowel implanted in the sheet metal base 31a.

On the glass epoxy substrate 31b, a light emitting / receiving device 32, a light emitting unit cover 33, a prism mirror 34
And a drive control circuit (not shown) for the semiconductor laser element 32c of the light receiving / emitting device 32, a circuit (not shown) for processing output signals of the photodetectors 32f and 32g, and the like. Are formed.

Further, a hole 31d is provided near the center of the glass epoxy substrate 31b (at a position corresponding to the convex portion 31c of the sheet metal base 31a). This hole 3
On the periphery of 1d, a ground connection land 31e of, for example, a conductive pattern is formed.

The optical disk device 20 incorporating the optical pickup 30 according to the present embodiment is configured as described above. At the time of assembly, as shown in FIG. It is brought on 31a. Then, when the glass epoxy substrate 31b is placed on the sheet metal base 31a, the projections 31c on the sheet metal base 31a fit into the holes 31d of the glass epoxy substrate 31c. Then, the glass epoxy substrate 31
As shown in FIG. 5, for example, a cream solder 37 is applied to the vicinity of the hole 31d of FIG. 5C, and the ground connection land 31e is soldered to the convex portion 31c by passing through a reflow furnace, and electrically connected. Is done. As a result, the glass epoxy substrate 31b is grounded to the sheet metal base 31a.

The optical disk device 20 assembled as described above operates as follows. First, when the spindle motor 22 of the optical disk device 20 rotates,
The optical disk 21 is driven to rotate. When the optical pickup 30 is moved in the radial direction of the optical disc 21, the optical axis of the objective lens 35 is
Is accessed by moving to the desired track position.

In this state, in the optical pickup 30, the light beam from the semiconductor laser element 32c of the light emitting / receiving device 32 enters the light emitting unit cover 33 and is reflected internally by the reflection surface, thereby forming an optical path. Is bent, the astigmatism is corrected, the light is emitted from the light emitting unit cover 33, reflected by the prism mirror 34 toward the optical disk 21, and is reflected through the objective lens 35.
Is focused on the signal recording surface. The return light from the optical disk 21 again enters the light emitting / receiving device 32 via the objective lens 35, the prism mirror 34, and the light emitting unit cover 33.
The light beam that has entered the trapezoidal prism 32d of the light emitting / receiving device 32 is focused on the photodetectors 32f and 32g.
Thereby, the signal of the optical disk 21 is reproduced based on the detection signals of the photodetectors 32f and 32g.

At this time, the signal demodulator 25 is provided with a photodetector 32
The tracking error signal and the focusing error signal are detected based on the detection signals from f and 32g. Then, the servo circuit 29 servo-controls a drive current to the focusing coil 36d and the tracking coil 36e via the optical disk drive controller 24.
That is, the magnetic field generated in the focusing coil 36d acts on the magnetic field generated by the magnet 36g and the yoke 36f, so that the movable portion 36c is moved and adjusted in the focusing direction, and the focusing is performed. The magnetic field generated in the tracking coil 36e acts on the magnetic field generated by the magnet 36g and the yoke 36f, so that the movable portion 36c is moved and adjusted in the tracking direction, and tracking is performed.

As described above, according to the present embodiment, the glass epoxy substrate is grounded to the sheet metal base via the projection to which the ground connection land is soldered. The optical base itself is made smaller and lighter by sheet metal at a lower cost, so that the optical pickup and the entire optical disc device are manufactured smaller, lighter and lower cost, and the optical base is formed on the sheet metal base. The glass epoxy board to be placed is
With a simple configuration, it is reliably connected to the sheet metal base at low cost.

Here, the light emitting / receiving device 32 mounted on the glass epoxy substrate 31b is
Is grounded from the ground connection land 31e to the sheet metal base 31a to be surely grounded.

In the optical disk device 20 and the optical pickup 30 according to the above-described embodiment, the light emitting / receiving device 32 in which the semiconductor laser element and the photodetector are integrally formed is used as the laser light source. Obviously, the laser light source and the photodetector may be configured separately.

[0042]

As described above, according to the present invention, a small and lightweight optical base can be obtained, and the glass epoxy substrate mounted on the surface thereof can be easily grounded. A pickup and an optical disk device using the same are provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of an embodiment of an optical disk device incorporating an optical pickup according to the present invention.

FIG. 2 is a perspective view showing a configuration of an optical pickup in the optical disk device of FIG.

FIG. 3 is an enlarged perspective view of a light emitting and receiving device in the optical pickup of FIG. 2;

FIG. 4 is an exploded perspective view of a sheet metal base and a glass epoxy substrate in the optical pickup of FIG. 2;

FIG. 5 is a partially enlarged sectional view of a sheet metal base and a glass epoxy substrate in the optical pickup of FIG. 2;

FIG. 6 is a side view showing an optical system in an example of a conventional optical pickup.

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

[Brief description of reference numerals]

Reference numeral 20: optical disk device, 21: optical disk, 2
2 ... Spindle motor, 23 ... Control unit, 24
..Optical disk drive controller, 25 ... signal demodulator, 26 ... error correction circuit, 27 ... interface, 28 ... head access control unit, 30 ...
・ Optical pickup, 31 ・ ・ ・ Optical base, 31a ・
..Sheet metal base, 31b ... Glass epoxy board, 3
1c ... convex part (half blanking dowel), 31d ... hole, 31
e: Land for ground connection, 32: Light receiving / emitting device
33: light emitting unit cover, 34: prism mirror,
35: Objective lens, 36: Biaxial actuator, 37: Cream solder.

Claims (4)

[Claims] A light source for emitting a light beam; a light focusing means for focusing the light beam emitted from the light source on a signal recording surface of a rotationally driven optical disk; and a light source between the light source and the light focusing means. The light source, the light separating means, and the light detector; and a light detector having a light receiving unit for receiving a return light beam from a signal recording surface of the optical disc separated by the light separating means. A supporting optical base, wherein the optical base includes a conductive metal base and a substrate on which a light source and a photodetector mounted thereon are mounted, and on the metal base, An optical pickup, wherein a convex portion having the same height as the substrate is formed, and the substrate has a hole having a connection land formed corresponding to the convex portion. 2. The optical pickup according to claim 1, wherein the convex portion is a half-cut dowel formed on the metal base. 3. The optical pickup according to claim 2, wherein the convex portion is a dowel implanted on the metal base. 4. A light converging means for converging a light beam emitted from a light source onto a signal recording surface of an optical disc; a light detecting means having a light receiving section for receiving a return light beam from the signal recording face of the optical disc; An electromagnetic drive unit capable of moving the focusing unit in two axial directions; an arithmetic unit for obtaining a servo signal based on a signal from a light receiving unit of the light detection unit; and a drive unit driven by the electromagnetic drive unit based on the servo signal A servo means for supplying a current; and an optical base for supporting the light source, the light detecting means, and the arithmetic unit, wherein the optical base is a conductive metal base, a light source mounted thereon, and a light detecting means. A substrate on which a container is mounted, and a projection having the same height as the substrate is formed on the metal base, and the substrate includes a connection land formed corresponding to the projection. Having holes Optical disk apparatus according to symptoms.