JPH1092006A - Optical pickup and optical disk device - Google Patents

Abstract

(57) [Problem] To enable various optical components such as a light source and a photodetector to be mounted at a predetermined position with high accuracy even with low adhesion accuracy of an optical base glass epoxy substrate by a simple configuration. An optical pickup and an optical disk device using the same. SOLUTION: The optical base 31 of the optical pickup is
The light source and the photodetector 32 are constituted by a sheet metal base 31a made of sheet metal and a glass epoxy substrate 31b mounted thereon, and the optical base 31 is formed by a reference mark 40 provided on the sheet metal base. So that it is positioned in the upper predetermined position.

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 disk (hereinafter referred to as "optical disk"). The present invention relates to an optical disk device provided with the optical pickup.

[0002]

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

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
Is a lens holder 1 to which the objective lens 11 is attached.
2, a coil bobbin 13 attached to the lens holder 12 by bonding or the like, a suspension 14 made of an elastic material supporting the lens holder 12 at one end, and the other end of the suspension 14
And a mounting member 16 fixedly held on the fixed side such as 5.

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 (the objective lens 11 side in the drawing) is covered with a cover 19. The cover 19 is attached to the end 1 of the yoke.
The upper ends of 7a and 17b are connected to define 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.
By forming a spot at a correct position on the signal recording surface of the above and reproducing the recorded signal accurately, the objective lens 6 is moved in the biaxial direction by the biaxial actuator 10 based on a predetermined servo signal. Fine movement adjustment is performed. The servo of the objective lens 6 includes a tracking servo for finely moving the objective lens 6 along the radial direction of the optical disk D with respect to the recording track of the optical disk D, and a servo for approaching the signal recording surface of the optical disk D along the optical axis. Focusing servo for finely moving the objective lens 6 in the direction of separation is performed.

[0009]

By the way, the two-axis actuator 10 having such a structure has a base 15
However, as shown in FIG. 8, in a state where the space is adjusted with respect to the optical base 8 of the optical pickup 1, it is fixed and held via the adjustment plate 15a by, for example, soldering. The optical base 8 is an optical base formed of a sheet metal made of iron, and has on its upper surface a light emitting / receiving device 8a in which the semiconductor laser element 2 as a light source and the photodetector 7 are integrated, a chip capacitor 8b, Glass epoxy board 9 on which volume 8c and pin connector 8d are mounted
Is placed and attached. Further, the mirror base 8e for bending the optical path of the light emitting and receiving device 8a is mounted on the upper surface of the optical base 8, and the cover 8f is mounted from above, so that the entire optical base 8 is covered. A guide spring 8g is attached to the lower surface.

Here, as shown in FIG. 9, the glass epoxy substrate 9 has a cutout 9a in the area where the light emitting and receiving device 8a is mounted, and the light emitting and receiving device 8a is inserted into the cutout 9a. Then, it is directly fixed on the optical base 8 made of sheet metal by die bonding or the like. The light emitting and receiving device 8a is bonded to the connection pattern 9b formed on the glass epoxy substrate 9 in order to supply a drive current to the semiconductor laser element 2 and the photodetector 7 and to take out a detection signal. The connection is made electrically via a wire 9c.

The light receiving / emitting device 8a is conventionally, for example, shown in FIG.
As shown in FIG. 0, on the optical base 8, one side edge of the light emitting / receiving device 8 a is equidistant L on both sides based on the reference mark 9 d formed by the conductive pattern formed on the glass epoxy substrate 9. After being positioned at a predetermined position, the mirror assembly 8e and the biaxial actuator 10 are positioned and adjusted with reference to the mounting holes provided on the optical base 8.

However, in the above configuration, since the glass epoxy substrates 9 are adhered on the optical base 8, the glass epoxy substrates 9 are displaced from each other. About 0.15 mm. Therefore, if the position of the glass epoxy substrate 9 is shifted with respect to the optical base 8, the above-described positioning of the light emitting / receiving device 8a with respect to the optical base 8 will also occur. Accordingly, the other optical components, that is, the mirror assembly 8e and the biaxial actuator 10 are similarly mounted with their positions shifted with respect to the optical base 8. Thus, in order to avoid such misalignment, it is necessary to increase the precision with which the glass epoxy substrate is adhered to the optical base 8, resulting in a problem that the assembly cost is increased.

In view of the above, the present invention has a simple structure and allows various optical components such as a light source and a photodetector to be positioned at a predetermined position with high accuracy even when the adhesion accuracy of an optical base glass epoxy substrate is low. An object of the present invention is to provide an optical pickup and an optical disk device using the same, which can be attached.

[0014]

According to the present invention, there is provided a light source for emitting a light beam, light focusing means for focusing the light beam emitted from the light source on a signal recording surface of an optical disk, A light separating unit disposed between the light source and the light focusing unit, a photodetector 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 unit, An optical base supporting the light source, the light separating means, and the photodetector; and a driving means for driving and adjusting the light focusing means in two axial directions, wherein the optical base is provided on a metal base and provided thereon. This is achieved by an optical pickup comprising a substrate, wherein the light source and the photodetector are positioned at predetermined positions on an optical base by reference marks provided on the metal base.

According to the above construction, the optical base is composed of the metal base and the substrate fixed thereon, and the light source and the photodetector, which are optical parts, are preferably integrated. The light emitting / receiving device is positioned at a predetermined position on the metal base based on the reference mark formed on the sheet metal base. Therefore, even if the substrate is stuck to the metal base with displacement, the light source and the photodetector, preferably the light emitting and receiving device in which these are integrated, are accurately positioned with respect to the metal base. Will be. As a result, other optical components including, for example, a biaxial actuator can be accurately positioned with respect to the optical base without causing a positional shift.

[0016]

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 mirror assembly 33 having a reflection 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 mirror assembly 33, and the prism mirror 34 are optically supported movably in the radial direction of the optical disk 21 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 microprism 32d has a semi-transmissive film (not shown) formed on the inclined surface 32e.

As a result, 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, travels upward, and travels upward. The reflecting surface 33a of the solid 33, the prism mirror 34, and the objective lens 35
Via the optical disk 21. Also,
The return light from the signal recording surface of the optical disk 21 passes through the inclined surface 32e of the microprism 32d via the objective lens 35, the prism mirror 34, and the reflection surface 33a of the mirror assembly 33, and is transmitted to the bottom surface of the microprism 32d. Reach. 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, and the detection signals of the respective light receiving sections are 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.
The third photodetector 32h includes a semiconductor laser device 32c
This is for monitoring the light emission intensity.

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 mirror assembly 33 includes the semiconductor laser device 3
After the laser light beam traveling upward from 2c enters the mirror assembly 33, the laser light beam is internally reflected by the reflection surface formed on the surface thereof, and travels in the mirror assembly 33 again in a substantially horizontal direction. It is configured as a so-called internal reflection type optical path bending mirror that is emitted from the solid 33. Here, the mirror assembly 33 is formed of a transparent resin capable of transmitting a laser light beam from the semiconductor laser element 32c, and is placed at a predetermined position on the optical base 31 so that a reflection surface is formed. It is positioned at a predetermined position.

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

The objective lens 35 is a light focusing means. In this case, the objective lens 35 is a convex lens,
Is focused on a desired track on the signal recording surface of the optical disk 21 driven to rotate. Therefore, various elements such as a hologram element are used as long as they perform the same function.

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, ie, a focusing direction and a tracking direction. The biaxial actuator 36 has a fixed portion 36a attached via an adjustment plate (not shown) in a state where the skew is adjusted with respect to the optical base 31, and two pairs of left and right parallel to the fixed portion 36a. Elastic support member 3
6b movable part 36 supported movably in two axial directions
c, a focusing coil 36d attached to the movable portion 36c, and a tracking coil 36e.

On the other hand, a yoke 36f disposed on the optical base 31 so as to face each other with the focusing coil 36d and the tracking coil 36e interposed therebetween, 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.

The optical base 31 is a metal base member, as shown in FIGS. 4 and 5, for example, a sheet metal base 31a made of a sheet metal and a glass epoxy substrate as a substrate mounted thereon, for example. 31b.

On the glass epoxy substrate 31b, a light emitting / receiving device 32, a mirror assembly 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. Here, the light emitting and receiving device 32 is, as shown in FIG.
1b, the sheet metal base 31a
It is mounted directly on top by die bonding. Further, the light emitting / receiving device 32 includes a glass epoxy substrate 31b for supplying a drive current to the semiconductor laser element 32c and the photodetectors 32f and 32g and extracting a detection signal.
The connection pattern 38 formed above is electrically connected via a bonding wire 39.

Further, as shown in FIGS. 4 and 5, the sheet metal base 31a has a reference mark 40 indicating a predetermined mounting position of the light emitting / receiving device 32.

The optical disk device 20 incorporating the optical pickup 30 according to the present embodiment is constructed as described above. When assembling, one side edge of the light emitting / receiving device 32 is first shown in FIG. As shown, the glass epoxy substrate 31b
Based on the reference mark 40 formed by the conductive pattern formed thereon, the light emitting / receiving device 32
Is positioned at a predetermined position on the optical base 31a, and is fixed by die bonding or the like. After that, the mirror assembly 33 and the biaxial actuator 36 are positioned and adjusted with reference to the mounting hole provided on the sheet metal base 31a.

Therefore, even if the glass epoxy substrate is adhered to the sheet metal base with a displacement, the light source and the photodetector, preferably the light emitting and receiving device in which these are integrated, are attached to the sheet metal base. Will be accurately positioned. As a result, other optical components including, for example, a biaxial actuator can be accurately positioned with respect to the optical base without causing a positional shift. Thus, since each optical component is accurately positioned with respect to the sheet metal base of the optical base, and the bonding accuracy of the glass epoxy substrate to the sheet metal base does not need to be very high, assembly can be performed easily and at low cost. Will be

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 of the light emitting / receiving device 32 enters the mirror assembly 33, and is reflected internally by the reflection surface 33a to form an optical path. Is bent and emitted from the mirror assembly 33, reflected by the prism mirror 34 toward the optical disk 21, and converged on the signal recording surface of the optical disk 21 via the objective lens 35. 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 mirror assembly 33. Then, the light is focused on a photodetector (not shown) of the light emitting / receiving device 32. Thereby, the signal of the optical disk 21 is reproduced based on the detection signal of the photodetector.

At this time, the signal demodulator 25 detects a tracking error signal and a focusing error signal based on the detection signal from the photodetector. And the servo circuit 2
9 is via the optical disk drive controller 24,
The servo control of the drive current to the focus coil and the tracking coil is performed. That is, the magnetic field generated in the focusing coil acts on the magnetic field generated by the magnet 36h and the yoke 36g, so that the movable portion 36c is moved and adjusted in the focusing direction, and the focusing is performed. Also, the magnetic field generated in the tracking coil is
By acting on the magnetic field generated by the magnet 36h and the yoke 36g, the movable portion 36c is moved and adjusted in the tracking direction, and tracking is performed.

In the optical disk device 20 and the optical pickup 30 according to the above-described embodiment, a light emitting / receiving device 32 in which a semiconductor laser element and a photodetector are integrally formed is used as a laser light source. It is obvious that the present invention can be applied even if the laser light source and the photodetector are configured separately. In this case, the laser light source and the photodetector are accurately positioned at predetermined positions on the sheet metal base 31a based on the reference marks 40 formed on the sheet metal base 31a.

[0041]

As described above, according to the present invention, various optical components such as a light source and a photodetector can be positioned at a predetermined position by a simple structure, even if the adhesion accuracy of an optical base glass epoxy substrate is low. An optical pickup and an optical disk device using the same, which can be attached to the optical disc with high accuracy, can be 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 a partially enlarged perspective view showing a relationship between a light emitting / receiving device and an optical base in the optical pickup of FIG. 2;

FIG. 5 is a partially enlarged plan view showing a relationship between a light emitting / receiving device and an optical base 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.

FIG. 8 is an exploded perspective view showing the configuration of the optical pickup of FIG.

9 is a partially enlarged perspective view showing a relationship between a light emitting / receiving device and an optical base in the optical pickup of FIG. 6;

10 is a partially enlarged plan view showing a relationship between a light receiving and emitting device and an optical base in the optical pickup of FIG. 6;

[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
2 ··· light emitting / receiving device, 32c ··· semiconductor laser element (light source), 32f, 32g ··· photodetector, 33 ···
Mirror assembly, 34 ... Prism mirror, 35 ...
Objective lens, 36 ... biaxial actuator, 37 ...
Notch, 38: connection pattern, 39: bonding wire, 40: reference mark.

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 an optical disc; and a light source disposed between the light source and the light focusing means. A light separating unit; 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 unit; and an optical base supporting the light source, the light separating unit, and the light detector And a driving means for driving and adjusting the light focusing means in two axial directions, wherein the optical base is composed of a metal base and a substrate provided thereon, and wherein the light source and the photodetector are provided. Is positioned at a predetermined position on the optical base by a reference mark provided on the metal base. 2. The light source and the light detector are configured as an integrated light emitting and receiving device, and are mounted on the metal base and electrically connected to a connection pattern formed on the substrate. The optical pickup according to claim 1, wherein 3. The substrate is a glass epoxy substrate,
The optical pickup according to claim 2, wherein the glass epoxy substrate has a cutout in a region corresponding to a mounting position of the light emitting and receiving device. 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; A driving unit that drives and adjusts the focusing unit in two axial directions; an operation unit that obtains a servo signal based on a signal from a light receiving unit of the light detection unit; and a driving current that is supplied to the driving unit based on the servo signal. Servo means for supplying; an optical base supporting the light source, the light separating means and the light detector; and a driving means for driving and adjusting the light focusing means in two axial directions, wherein the optical base is a metal base. And a substrate provided thereon, wherein the light source and the photodetector are positioned at predetermined positions on the optical base by reference marks provided on the metal base. Optical disc apparatus according to claim.