JPH1064108A - Light receiving / emitting device and optical pickup using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emitting / receiving device which has a small structure, maintains reliability without a sealing structure, and has an optical branching function and a deflecting function. SOLUTION: A light receiving element 22d, 22e formed on a first semiconductor substrate 22a, a light emitting element 22c formed on a second semiconductor substrate 22b mounted on the first semiconductor substrate, On one semiconductor substrate, there is provided a hollow portion 22a disposed so as to cover the light receiving element, and this hollow portion reflects the laser light emitted from the light emitting element to an inner surface, and the incident light from the outside. And a light splitting component 23 having a light splitting surface 23b that transmits light. The light receiving and emitting device 22 is configured so that light emitted from the light splitting surface into the hollow portion enters the light receiving element. I do.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting / receiving device for recording and / or reproducing an optical disk such as an optical disk, a magneto-optical disk, and a phase change disk, and an optical pickup and an optical disk device using the same. It is about.

[0002]

2. Description of the Related Art Conventionally, an optical pickup for a compact disk is constructed, for example, as shown in FIG. In FIG. 5, the optical pickup 1 includes an objective lens 2, a base 3, optical path bending mirrors 4 and 5 disposed on the base 3, and a light emitting / receiving device 6.

The optical pickup 1 converts the laser light emitted from the light receiving / emitting device 5 through the optical path bending mirrors 4 and 5 and the objective lens 2 when the objective lens 2 is moved in the focusing direction and the tracking direction. The laser beam (return light) reflected from the signal recording surface of the optical disk 7 is focused and focused on a certain point on the signal recording surface of the optical disk 7 that is driven to rotate above the objective lens 2.
Then, the light enters the light receiving / emitting device 6 via the optical path bending mirrors 5 and 4.

Here, the optical path bending mirrors 4 and 5 are rising mirrors fixedly arranged on the base portion 3, respectively, and guide the laser light emitted from the light emitting / receiving device 6 to the objective lens 2. The light from the optical disk 7 is guided from the objective lens 2 to the light emitting / receiving device 6. Further, the objective lens 2 is moved and adjusted in the focusing direction and the tracking direction by a biaxial actuator (not shown), so that the laser light emitted from the light receiving / emitting device 6 passes through the bending mirrors 4 and 5 and the objective lens 2. hand,
The focus is focused on the signal recording surface of the optical disc 7. The laser light (return light) reflected on the signal recording surface of the optical disk 7 is incident on the light emitting / receiving device 6 via the objective lens 2 and the bending mirrors 5 and 4.

[0005] As shown in FIG.
A second semiconductor substrate 6b for light output is mounted on the first semiconductor substrate 6a, and a semiconductor laser 6c as a light emitting element is mounted on the second semiconductor substrate 6b. On a first semiconductor substrate 6a in front of the semiconductor laser 6c, a microprism 6d as a trapezoidal semi-transmissive reflection component is provided.
However, the semiconductor laser 6c is installed with its inclined surface as the semi-transmissive surface facing the semiconductor laser 6c. Further, the light emitting and receiving device 6 is entirely covered with a cover 8.

As a result, the light beam emitted from the semiconductor laser 6c along the surface of the second semiconductor substrate 6b is reflected by the inclined surface of the microprism 6d, travels upward in FIG. It will proceed toward the bending mirror 4. The light beams reflected by the bending mirrors 4 and 5 are converged on the signal recording surface of the optical disk 7 via the objective lens 2. The return light from the signal recording surface of the optical disk 7 is again transmitted to the objective lens 2, the bending mirror 5,
4, the light enters the microprism 6 d from the inclined surface of the microprism 6 d and reaches the bottom surface of the microprism 6 d. The return light that has reached the bottom surface of the microprism 6d partially transmits through the bottom surface, and is partially reflected by the bottom surface, and travels toward the top surface of the microprism 6d.

[0007] Here, a first photodetector 6e is formed on the first semiconductor substrate 6a below the return light incident position of the microprism 6d. The return light reflected on the bottom surface is reflected on the top surface of the microprism 6d, and is incident on the bottom surface of the microprism 6d again.
A second photodetector 6f is formed on the first semiconductor substrate 6a below the bottom portion of the microprism 6d where the return light reflected by the upper surface of the microprism 6d is incident. The first photodetector 6e and the second photodetector 6f are each divided into a plurality of sensor blocks, and the detection signals of each sensor block are output independently. The second semiconductor substrate 6
On b, a third photodetector 6g is provided on the side opposite to the emission side of the semiconductor laser 6c. The third light detector 6g is for monitoring the light emission intensity of the semiconductor laser 6c.

[0008] The optical pickup 1 constructed as described above.
According to the method, the laser light emitted from the semiconductor laser 6c of the light receiving / emitting device 6 enters the inclined surface of the microprism 6d, and is reflected by the inclined surface. Micro prism 6d
The laser light reflected on the inclined surface of
Then, the light beam is focused on a signal recording surface of the optical disc 7 at a desired track position via the objective lens 2. The return light from the optical disk 7 is again incident on the inclined surface of the microprism 6d of the light receiving / emitting device 6 via the objective lens 2 and the rising mirror 6a, and is transmitted through the inclined surface to generate light inside the microprism 6d. Proceed to.

The return light that has entered the microprism 6d reaches the bottom surface of the microprism 6d. The return light incident on the bottom surface is partially transmitted and partially reflected toward the upper surface of the microprism 6d. The return light passing through the bottom surface is incident on the first photodetector 6e, while the return light reflected on the bottom surface is reflected by the micro prism 6d.
Is reflected by the upper surface of the micro prism 6d, passes through the bottom surface of the microprism 6d, and enters the second photodetector 6f.

As described above, the return light is transmitted to the first photodetector 6e.
And the light enters the second photodetector 6f, so that the photodetector 6e
And 6f, based on a detection signal from each sensor block, a reproduction signal, for example, by a so-called differential three-division method,
A focus signal is detected, and a tracking error is detected based on a difference between detection signals of the respective sensor units of the first photodetector 6e.

[0011]

In the optical pickup 1 having such a structure, since the light receiving / emitting device 6 is used, the inclined surface as the semi-transmissive surface of the microprism 6d of the light receiving / emitting device 6 is used. If dirt, dust, or the like adheres to the light emitting device 6, the emitted light beam L1 from the light emitting and receiving device 6 and the incident light beam (return light beam) L2 to the light receiving and emitting device 6 are directly affected. At this time, since the optical effective diameter is relatively small, the characteristic deterioration of the optical pickup is very large. Therefore, a structure for totally sealing the light emitting and receiving device 6 with a sealing resin or the like is required.

Further, in order to facilitate the handling in the assembling process of the optical pickup, a light beam which enters the inclined surface of the microprism 6d from the semiconductor laser element 6c and is reflected by the inclined surface is shown in FIG. In the case of such a design that the light beam is emitted vertically upward as described above, the micro prism 6d needs to be emitted in order to prevent the return light beam L2 focused on the upper surface of the micro prism 6d from being affected by the inclined surface. A material having a high refractive index at the wavelength of the light beam L1 must be used.

Furthermore, in the light emitting and receiving device 6 in which the light emitting unit and the light receiving unit are integrally sealed, it is necessary to deflect the light beam using the bending mirrors 4 and 5 in order to reduce the size of the optical pickup. Therefore, the number of parts increases, and assembling accuracy decreases, which is likely to be a factor that impairs productivity.

On the other hand, when the sealing structure is not used, the stability of the inclined surface of the microprism 6d against environmental changes is required, which greatly restricts the optical design and lowers the reliability. There is a problem that occurs.

In view of the above, the present invention provides a light receiving / emitting device and an optical pickup which have a small structure, maintain reliability without a sealing structure, and have a light branching function and a deflection function. And an optical disk device using the same.

[0016]

According to the present invention, there is provided a light receiving element formed on a first semiconductor substrate and a light receiving element formed on a second semiconductor substrate mounted on the first semiconductor substrate. And a hollow portion provided on the first semiconductor substrate so as to cover the light receiving device. One surface of the hollow portion is a laser beam emitted from the light emitting device. A light branching component having a light branching surface for internally reflecting the light and transmitting light incident from the outside, and light emitted from the light branching surface into the hollow portion is incident on the light receiving element. This is achieved by the light receiving and emitting device described above.

According to the above configuration, the light beam emitted from the light source enters the inside of the light branching component, is internally reflected at the light branching surface, emerges from the light branching component, and passes through the light focusing means. To focus on the signal recording surface of the optical disk. The return light from the signal recording surface of the optical disk enters the inside of the optical branching component, passes through the optical branching surface, and enters the light receiving element. Thereby, based on the detection signal of the light receiving element,
The reproduction of the optical disk is performed.

Here, since the light branching component is provided so as to cover the light receiving element formed on the first semiconductor substrate of the light receiving and emitting device, the light receiving element is sealed by the light branching component. become. Further, since the reflection by the light branching surface of the light branching component is performed on the inner surface, the inner surface contributing to the reflection of the light branching surface does not affect the light flux due to dirt, dust and the like.

[0019]

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 a light emitting / receiving device and an optical pickup according to the present invention. In FIG. 1, an optical disk device 10 includes:
A spindle motor 12 as driving means for rotating the optical disk 11 and a signal beam are irradiated on a signal recording surface of the rotating optical disk 11 to record a signal. An optical pickup 20 for reproducing and a control unit 13 for controlling these are provided. Here, the control unit 13 includes an optical disk controller 14, a signal demodulator 15, an error correction circuit 16, an interface 17, a head access control unit 18, and a servo circuit 19.

The optical disk controller 14 controls the drive of the spindle motor 12 at a predetermined rotation speed. The signal demodulator 15 demodulates the recording signal from the optical pickup 20, corrects the error, and sends the signal to an external computer or the like via the interface 17. Thus, an external computer or the like can receive a signal recorded on the optical disk 11 as a reproduction signal.

The head access control unit 18 moves the optical pickup 20 to a predetermined recording track on the optical disk 11, for example, by a track jump or the like. The servo circuit 19 moves the objective lens held by the biaxial actuator of the optical pickup 20 in the focusing direction and the tracking direction at the moved predetermined position.

FIG. 2 shows an optical pickup incorporated in the optical disk device 10. In FIG.
The optical pickup 20 is provided with a semiconductor laser element as a light source and a photodetector 22 integrally mounted on an optical base 21 (see FIG. 3).
A light splitting part 23 constituting a part of a light receiving and emitting device; a prism mirror 24 as a rising mirror and an objective lens 25 as a light focusing means; and a two-axis for moving the objective lens 25 in two axial directions. And an actuator 26.

Here, the optical elements other than the objective lens 25, that is, the light receiving / emitting device 22, the light splitting component 23, and the prism mirror 24 are connected to the optical disk 1 by means (not shown).
Each of the optical bases 21 is fixedly held on one of the optical bases 21 movably supported in the radial direction.

Here, the light emitting and receiving device 22 is configured, for example, as shown in FIG. In FIG. 3, a light emitting / receiving device 22 includes a first semiconductor substrate 22a on which a second semiconductor substrate 22b for light output is mounted, and a semiconductor laser element 22 serving as a light emitting element on the second semiconductor substrate 22b.
c is mounted. On the first semiconductor substrate 22a in front of the semiconductor laser element 22c, a light branching component 23 having a trapezoidal longitudinal section is formed on an inclined surface 23 inside the hollow portion 23a.
b is set with the semiconductor laser element 22c side.

Here, the optical branching component 23 is
A light splitting surface is formed on the inclined surface 23b of 3a. That is, in order to make the inclined surface 23b a light splitting surface, a semi-transmissive reflective film is formed here, an inner reflective film is formed on the outer inclined surface 23c, and a reflective film is formed on the upper surface of the hollow portion 23a. ing. Thereby, the semiconductor laser element 22c
The light beam emitted along the surface of the second semiconductor substrate 22b is reflected by the inclined surface 23b of the light splitting component 23, is further totally reflected by the outer inclined surface 23c, and is emitted from the semiconductor laser element 22c. Go in the direction
The light is emitted in the horizontal direction from the opposite side surface 23d of the light splitting component 23, and the prism mirror 24 and the objective lens 25 described above are emitted.
Through the optical disk 11.

The return light from the signal recording surface of the optical disk 11 follows the same optical path as the optical path toward the optical disk 1 in reverse, and again the objective lens 25 and the prism mirror 24
Through the side surface 23d of the light splitting component 23, is internally reflected by the inclined surface 23c, enters the inclined surface 23b, passes through the inclined surface 23b, enters the hollow portion 23a, and It reaches the surface of one semiconductor substrate 22a. A part of the return light that has reached the surface of the first semiconductor substrate 22a transmits through the surface and a part is reflected on the surface, and travels toward the upper surface of the hollow portion 23a.

Here, a first photodetector 22d is formed on the first semiconductor substrate 22a at the return light incident position. Further, the return light reflected on the surface is transmitted to the hollow portion 23.
reflected on the upper surface of the first semiconductor substrate 22a again.
Is incident on the surface. A second photodetector 22e is formed on the first semiconductor substrate 22a on which the return light reflected on the upper surface of the hollow portion 23a is incident. The first photodetector 22d and the second photodetector 22e are each divided into a plurality of light receiving units, and the detection signals of each light receiving unit are output independently.

A third photodetector 22f is provided on the second semiconductor substrate 22b on the side opposite to the emission side of the semiconductor laser element 22c. This third photodetector 22
f is for monitoring the light emission intensity of the semiconductor laser element 22c.

The semiconductor laser element 22c is a light emitting element utilizing recombination light emission of a semiconductor, and is used as a light source.

The light splitting component 23 is made of glass or plastic whose refractive index with respect to the frequency of the laser beam from the semiconductor laser element 22c is 1.5.
If it is an optically transparent material having a refractive index of 1.55 or less,
Any other material can be used.

The prism mirror 24 is a mirror disposed at an angle of 45 degrees on the optical base 21 and reflects a light beam traveling in a substantially horizontal direction from the optical path bending mirror 23 upward in the vertical direction. It is made to let.

The objective lens 25 is a convex lens, and focuses the light from the prism mirror 24 on a desired track on the signal recording surface of the optical disk 11 that is driven to rotate.

Here, the objective lens 25 is supported by a biaxial actuator 26 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 26 is attached to the optical base 21 in a state where the skew is adjusted.
6a, a movable part 26c movably supported in two axial directions by two pairs of left and right elastic support members 26b parallel to the fixed part 26a, a focusing coil 26d attached to the movable part 26c, and tracking. Coil 26
e.

On the other hand, a yoke 26f disposed on the optical base 21 so as to oppose each other with the focusing coil 26d and the tracking coil 26e interposed therebetween, and a magnet 26 mounted inside the yoke 26f.
g is provided.

Accordingly, when a drive current flows through the focusing coil 26d, the focusing coil 26d
Magnetic field generated by the magnet 26g and the yoke 26f
The movable portion 26c is driven in the focus direction by interaction with the magnetic flux flowing through the movable portion 26c. When a drive current flows through the tracking coil 26e, the magnetic field generated in the tracking coil 26e interacts with the magnetic flux flowing through the magnet 26g and the yoke 26f to drive the movable portion 26c in the tracking direction. Thus,
The objective lens 25 held by the movable portion 26c is driven and controlled in the biaxial directions.

The optical disk device 10 incorporating the optical pickup 20 according to the present embodiment is configured as described above, and operates as follows. First, the optical disk 11 is rotationally driven by the rotation of the spindle motor 12 of the optical disk device 10. Then, by moving the optical pickup 20 in the radial direction of the optical disc 11, the optical axis of the objective lens 25 is moved to a desired track position of the optical disc 11, thereby performing access.

In this state, in the optical pickup 20, the light beam from the semiconductor laser element 22c of the light receiving / emitting device 22 enters the inside of the light branching component 23 and is reflected internally by the inclined surface 23b. Then, the optical path is bent, further internally reflected by the inclined surface 23c, travels in the horizontal direction in FIG. 4, exits from the side surface 23d of the light splitting component 23, and is reflected toward the optical disk 11 by the prism mirror 24. And the optical disk 11 is passed through the objective lens 25.
Is focused on the signal recording surface. The return light from the optical disk 11 travels in the same optical path as when heading toward the optical disk 11 in the opposite direction, and again enters from the side surface 23d of the light splitting component 23 via the objective lens 25 and the prism mirror 24. Then, after being internally reflected by the inclined surface 23c of the light branching component 23, the light is transmitted through the inclined surface 23b, and is detected by the photodetectors 22d and 22e.
Focus on Thereby, the signal of the optical disk 11 is reproduced based on the detection signals of the photodetectors 22d and 22e.

At this time, the signal demodulator 15 is connected to the photodetector 22
The tracking error signal and the focusing error signal are detected based on the detection signals from d and 22e. Then, the servo circuit 19 servo-controls a drive current to the focusing coil 26d and the tracking coil 26e via the optical disk drive controller 14.
That is, the magnetic field generated in the focusing coil 26d acts on the magnetic field generated by the magnet 26g and the yoke 26f, so that the movable portion 26c is moved and adjusted in the focusing direction, and the focusing is performed. The magnetic field generated in the tracking coil 26e acts on the magnetic field generated by the magnet 26g and the yoke 26f, so that the movable portion 26c is moved and adjusted in the tracking direction, and tracking is performed.

Here, in the light receiving / emitting device 22, the region of the photodetectors 22d and 22e is formed by the hollow portion 23 of the light branching component 23.
a, the light splitting component 2
3 will be sealed. Therefore, the photodetector 2
Regarding 2d and 22e, they are sealed without adopting the sealing structure, so that the reliability is improved and
The effects of dirt, dust and the like are reduced.

The light beam from the semiconductor laser element 22c is internally reflected by the inclined surface 23b of the light splitting component 23, and the return light beam from the optical disk is transmitted through the inclined surface 23b of the light splitting component 23. Since the inclined surface 23b, which is a light splitting surface, is an inner surface of the light splitting component 23, the reflecting surface is not affected by dirt, dust, and the like. Therefore, deterioration of the characteristics of the optical pickup 20 can be prevented without employing the sealing structure.

Further, since the light branching component 23 has the inclined surface 23c that reflects the light beam from the semiconductor laser element 22c toward the prism mirror 24 and acts as a so-called optical path bending mirror, the optical path bending is performed. A mirror is not required, and the entire optical pickup 20 and the optical disk device 10 can be made compact and at low cost.

In the optical disk device 10 and the optical pickup 20 according to the above embodiment, the two-axis actuator 26 is shown as having the elastic support member 26b, but is not limited to this. It is obvious that the two-axis actuator of the present invention may be used.

The optical disk device 10 and the optical pickup 20 according to the above-described embodiment are, for example, those for reproducing a compact disk, but are not limited thereto.
An optical disk device 10 for recording and / or reproducing an optical disk such as a mini disk (MD), an optical disk such as a magneto-optical disk (MO), and a phase change disk; Light emitting device 2
Obviously, the present invention can be applied to No. 2.

[0045]

As described above, according to the present invention, the reliability is maintained and the optical branching function and the deflecting function are provided without the sealing structure by the compact structure.
A light receiving / emitting device, an optical 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 including a light branching component in the optical pickup of FIG. 2;

4 is a cross-sectional view of a light emitting and receiving device including the light branching component of FIG.

FIG. 5 is a sectional view of a conventional optical pickup.

FIG. 6 is an enlarged perspective view showing a light emitting and receiving device in the optical pickup of FIG. 5;

FIG. 7 is an enlarged sectional view showing a light emitting and receiving device in the optical pickup of FIG. 5;

[Brief description of reference numerals]

10 optical disk device, 11 optical disk, 1
2 ... Spindle motor, 13 ... Control unit, 14.
..Optical disk drive controller, 15 ... signal demodulator, 16 ... error correction circuit, 17 ... interface, 18 ... head access control unit, 20 ...
・ Optical pickup, 21 ・ ・ ・ Optical base, 22 ・ ・
· Light receiving / emitting device, 23 ··· light branching component, 23a ··· hollow part, 23b ··· inclined surface (semi-transmissive reflecting surface) (light branching surface), 23c ··· inclined surface (reflective surface), 24 ... prism mirror, 25 ... objective lens, 26 ... biaxial actuator.

Claims (5)

[Claims] A light receiving element formed on a first semiconductor substrate; a light emitting element formed on a second semiconductor substrate mounted on the first semiconductor substrate; and a light emitting element formed on the first semiconductor substrate. A hollow portion disposed so as to cover the light receiving element, and one surface of the hollow portion internally reflects laser light emitted from the light emitting element and transmits external incident light. A light splitting component having a splitting surface, wherein light emitted from the light splitting surface into the hollow portion is incident on the light receiving element. 2. The light emitting / receiving device according to claim 1, wherein the light branching component is formed of a material having a refractive index of 1.55 or less with respect to a wavelength of laser light emitted from the light emitting element. . 3. The light splitting component includes a light beam reflected from the light splitting surface of the hollow portion from the light emitting element and a reflecting surface that deflects an incident beam transmitted through the light splitting surface by internal reflection. The light emitting and receiving device according to claim 1, wherein: 4. A light emitting and receiving device, and an optical device for focusing laser light emitted from the light emitting and receiving device on a signal recording surface of an optical disk and introducing return light from the signal recording surface of the optical disk into the light receiving and emitting device. An optical pickup comprising: a light-receiving / emitting device formed on a first semiconductor substrate; and a light-receiving element formed on a second semiconductor substrate mounted on the first semiconductor substrate. A light-emitting element, and a hollow portion disposed on the first semiconductor substrate so as to cover the light-receiving element, and one surface of the hollow portion reflects the laser light emitted from the light-emitting element to an inner surface. And a light splitting component having a light splitting surface for transmitting incident light from the outside, wherein light emitted from the light splitting surface into the hollow portion is incident on the light receiving element. Characteristic optical pickup H. 5. A light receiving and emitting device, and a light focusing device for focusing a light beam emitted from the light receiving and emitting device on a signal recording surface of an optical disc and introducing return light from the signal recording surface of the optical disc into the light receiving and emitting device. Means; a driving means capable of moving the light focusing means in two axial directions; a calculating section for obtaining a servo signal based on a signal from a light receiving section of the light detecting means; and the driving means based on the servo signal. An optical disk device including: a servo unit that supplies a drive current to the optical disk device, wherein the light receiving and emitting device includes: a light receiving element formed on a first semiconductor substrate; and a light receiving element mounted on the first semiconductor substrate. A light-emitting element formed on the second semiconductor substrate; and a hollow portion provided on the first semiconductor substrate so as to cover the light-receiving element. One surface of the hollow portion is separated from the light-emitting element. The emitted laser light A light branching component having a light branching surface for surface reflection and transmission of incident light from the outside, wherein light emitted from the light branching surface into the hollow portion is incident on the light receiving element. An optical disc device characterized by the above-mentioned.