JP2003077160A - Semiconductor laser device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the change of optical characteristic of a semiconductor laser device by suppressing the positional deviation of members constituting the semiconductor laser device. SOLUTION: The semiconductor laser device is provided with a semiconductor laser element 1 irradiating a recording medium 5 by laser beams, a diffraction grating 6 for diffracting a turn-back light of the laser beams emitted from the semiconductor laser element 1 on the recording medium 5, a photodetector 10 for receiving the turn-back light diffracted by the diffraction grating 6, a package 11 for housing the semiconductor laser element 1 and the photodetector 10, and a sealing substrate 2 for sealing the package 11, and in this device, the above package 11 and the sealing substrate 2 are adhered through an adhesive 12, and at this adhered part, a recessed part or a projected part is formed on at least one adhered surface of the package 11 and the sealing substrate 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser device, and more particularly to a semiconductor laser device suitable as a light source of an optical pickup device for recording and reproducing information on an information recording medium. Is.

[0002]

2. Description of the Related Art Conventionally, as a light source of an optical pickup device for recording and reproducing information on an information recording medium,
A semiconductor laser device having a structure as shown in FIG. 12 is used. In this semiconductor laser device, a semiconductor laser element 1 and a light receiving element 10 are provided in a package 11.
The package 11 includes a diffraction grating 6
It is sealed by being bonded to the sealing substrate 2 provided with the adhesive agent 12 via the adhesive 12. The diffraction grating 6 is arranged in the optical path from the semiconductor laser element 1 to the recording medium 5. Further, a collimator lens 3 and an objective lens 4 are arranged in the optical path leading to the recording medium 5.

Next, the operation of the semiconductor laser device will be described with reference to FIG. In the figure, for simplification, illustration of diffracted lights other than the −first-order diffracted light 7, the 0th-order diffracted light 8, and the + 1st-order diffracted light 9 is omitted. Laser light emitted from the semiconductor laser element 1 passes through the sealing substrate 2, is converted from a divergent light beam into a parallel light beam by the collimator lens 3, and is reflected by the surface of the recording medium 5 by the objective lens 4. Then, this reflected light passes through the objective lens 4 and the collimator lens 3 as return light, is diffracted by the diffraction grating 6, and is divided into −1st order diffracted light 7, 0th order diffracted light 8 and + 1st order diffracted light 9. The −1st order diffracted light 7 and the + 1st order diffracted light 9 are received by the light receiving element 10, respectively.

[0004]

In the semiconductor laser device, as described above, the semiconductor laser element 1 is used.
The package 11 accommodating the light receiving element 10 is sealed by being bonded to the sealing substrate 2 via the adhesive 12. As a result, dew condensation on the semiconductor laser device 1 and the light receiving device 10 can be prevented.

However, in the conventional semiconductor laser device, after the package and the sealing substrate are adhered to each other, a stress due to vibration is applied, or a strain stress due to a difference in thermal expansion coefficient is applied between the package and the sealing substrate. The adhesive strength between them was weakened, and the position of the sealing substrate was likely to be displaced by a small external pressure. Such positional deviation of the constituent members is a problem because it changes the optical characteristics of the semiconductor laser device.

Therefore, an object of the present invention is to provide a semiconductor laser device having stable optical characteristics.

[0007]

To achieve the above object, a first semiconductor laser device of the present invention comprises a semiconductor laser element for irradiating a recording medium with a laser beam, and a laser beam emitted from the semiconductor laser element. A diffraction grating that diffracts the return light from the recording medium, a light receiving element that receives the return light diffracted by the diffraction grating, a package that accommodates the semiconductor laser element and the light receiving element, and the package is sealed. A semiconductor laser device having a sealing substrate for stopping, wherein the package and the sealing substrate are adhered to each other via an adhesive, and at this adhesive portion, at least one of the package and the sealing substrate is provided. A concave portion or a convex portion is formed on the adhesive surface of.

With such a structure, the effective bonding area between the package and the sealing substrate is increased, and the stress due to the external stress and the strain stress of the sealing substrate due to the thermal expansion due to the multifaceted adhesive peeling direction. Can be diffused, so that a reduction in the adhesive strength between the package and the sealing substrate can be suppressed, and a positional shift between the two can be suppressed. As a result, it is possible to suppress changes in the optical characteristics of the semiconductor laser device.

In the first semiconductor laser device, the diffraction grating can be formed on the surface of the sealing substrate.

In addition, in the first semiconductor laser device, a light transmitting substrate disposed between the recording medium and the sealing substrate is further provided, and the diffraction grating is formed on the surface of the light transmitting substrate. May be.

Further, in the first semiconductor laser device, the laser light emitted from the semiconductor laser element, which is arranged between the recording medium and the diffraction grating, is returned to the recording medium. It is also possible to adopt a structure having a compound prism for splitting light.

In order to achieve the above object, a second semiconductor laser device of the present invention comprises a semiconductor laser element for irradiating a recording medium with a laser beam, and a laser beam emitted from the semiconductor laser element in the recording medium. A composite prism for splitting the return light, a diffraction grating for diffracting the return light split by the composite prism, a light receiving element for receiving the return light diffracted by the diffraction grating, the semiconductor laser element and the light receiving A semiconductor laser device comprising a package containing an element, wherein the diffraction grating is formed on a surface of a light transmitting substrate, and the light transmitting substrate and the composite prism are bonded via an adhesive,
In this adhesive portion, a concave portion or a convex portion is formed on the adhesive surface of at least one of the composite prism and the light transmitting substrate.

With such a structure, the effective bonding area between the composite prism and the light transmitting substrate is increased, and the multi-faceted adhesive peeling direction causes external stress and strain stress of the light transmitting substrate due to thermal expansion. Since the stress can be diffused, it is possible to suppress the decrease in the adhesive strength between the composite prism and the light transmitting substrate, and to suppress the positional deviation between the two. As a result, it is possible to suppress changes in the optical characteristics of the semiconductor laser device.

The second semiconductor laser device may have a structure in which the package is sealed by being bonded to the light transmitting substrate via an adhesive.

In this case, it is preferable that a concave portion or a convex portion is formed on the bonding surface of at least one of the package and the light transmitting substrate in the bonding portion between the package and the light transmitting substrate. This is because changes in the optical characteristics of the semiconductor laser device can be further suppressed.

Further, the second semiconductor laser device may further have a structure including a sealing substrate for sealing the package.

In this case, the package and the sealing substrate are adhered to each other via an adhesive, and a concave portion or a convex portion is formed on an adhesive surface of at least one of the package and the sealing substrate at the adhesive portion. Is preferably provided. This is because changes in the optical characteristics of the semiconductor laser device can be further suppressed.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 is a schematic view showing the structure of a semiconductor laser device according to the first embodiment of the present invention. In this semiconductor laser device, the package 1
A semiconductor laser element 1 and a light receiving element 10 are arranged in the unit 1. Further, this package 11 is used for the sealing substrate 2
It is sealed by being bonded via the adhesive 12.

As the package 11, for example, polyethylene terephthalate, epoxy resin, ABS resin, polycarbonate, polybutylene terephthalate, etc. can be used. As the sealing substrate 2, for example, glass and resins such as polycarbonate, polymethylmethacrylate, polystyrene, and polyolefin can be used. Moreover, as the adhesive 12, for example, an epoxy resin, an acrylic resin, a silicon resin, or the like can be used.

The shapes of the package 11 and the sealing substrate 2 are not particularly limited as long as they can be bonded to each other to form a space for accommodating the semiconductor laser element 1 and the light receiving element 10. Absent.

In this embodiment, a recess is formed on the surface of the sealing substrate 2 that is bonded to the package 11. The shape of the recess is not particularly limited, and for example, a shape having a trapezoidal cross section as shown in FIG. 1, a shape having a rectangular cross section as shown in FIG. 2, a shape having a V-shaped cross section, etc. are adopted. can do. Further, the number of recesses formed on the adhesive surface is not particularly limited, and for example, as shown in FIG. 3, it is possible to form a plurality of recesses at regular intervals.

The size of the recess is also not particularly limited. The width of the recess is, for example, 1 to 200 μm, preferably 50 to 100 μm, and the depth of the recess is, for example, 1
The thickness can be set to ˜200 μm, preferably 10 to 100 μm.

Regarding the method of forming the concave portion of the sealing substrate 2,
Although not particularly limited, for example, when glass is used, it can be performed by dicing using a dicing blade having a desired shape. When a resin is used, it can be formed by molding using a mold provided with a pattern having a desired shape.

A diffraction grating 6 is formed on the surface of the sealing substrate 2. The diffraction grating 6 can be formed by, for example, periodic unevenness formed on the surface of the sealing resin 2. The diffraction grating 6 is arranged in the optical path of the laser light emitted from the semiconductor laser element 1.

Further, in addition to the sealing body formed by the package 11 and the sealing substrate 2, the collimating lens 3 and the objective lens 4 are arranged in the optical path of the laser beam emitted from the semiconductor laser element 1, and the semiconductor is provided. A laser device is configured.

Next, the operation of the semiconductor laser device will be described with reference to FIG. Laser light emitted from the semiconductor laser element 1 passes through the sealing substrate 2, is converted from a divergent light beam into a parallel light beam by the collimator lens 3, and is reflected by the surface of the recording medium 5 by the objective lens 4. Then, this reflected light passes through the objective lens 4 and the collimator lens 3 as return light, is diffracted by the diffraction grating 6, and is divided into −1st order diffracted light 7, 0th order diffracted light 8 and + 1st order diffracted light 9. The −1st order diffracted light 7 and the + 1st order diffracted light 9 are received by the light receiving element 10, respectively. In the figure, for simplification, illustration of diffracted lights other than the −first-order diffracted light 7, the 0th-order diffracted light 8, and the + 1st-order diffracted light 9 is omitted.

In the above description, the concave portion is formed on the surface of the sealing substrate 2 at the bonding portion between the sealing substrate 2 and the package 11, but the concave portion may be formed on the surface of the package 11. Good. Furthermore, as shown in FIG. 4, recesses may be provided on both the surface of the sealing substrate 2 and the surface of the package 11.

Further, in the bonding portion between the sealing substrate 2 and the package 11, a convex portion can be formed instead of the above-mentioned concave portion. In this case, the number, shape and size of the convex portions are not particularly limited.

(Second Embodiment) FIG. 5 is a schematic diagram showing the structure of a semiconductor laser device according to a second embodiment of the present invention. In this semiconductor laser device, the package 1
1, a semiconductor laser element 1 and a light receiving element 10a, 1
0b is arranged. Furthermore, this package 11
It is sealed by being bonded to the sealing substrate 2 via the adhesive 12a.

As the materials of the package 11, the sealing substrate 2 and the adhesive 12a, the same materials as those in the first embodiment can be used. Moreover, the shapes of the package 11 and the sealing substrate 2 are not particularly limited as long as the spaces for accommodating the semiconductor laser element 1 and the light receiving element 10 can be formed by bonding them.

Further, similar to the first embodiment, a concave portion or a convex portion may be formed on the surface of at least one of the sealing substrate 2 and the package 11 at the bonding portion between the sealing substrate 2 and the package 11.

Further, in the example shown in FIG. 5, the semiconductor laser element 1 and the light receiving elements 10a and 10b are individually arranged in the package 11, but as shown in FIG. It is also possible to hybridize the light receiving elements 10a and 10b on the substrate 20 and arrange the substrate 20 in the package 11. In this case, when a surface-emitting type semiconductor laser device is adopted, chip-bonding may be performed on the substrate as it is with the light emitting surface facing upward. On the other hand, when the edge emitting semiconductor laser device is adopted, a recess having an inclined surface inclined by about 45 ° is formed on the substrate 20 by using a semiconductor processing technique, and a metal or a dielectric film is deposited on the inclined surface. After forming the reflection mirror 21 by doing so, the semiconductor laser element 1 may be arranged in the concave portion so that the emitting end face faces the reflection mirror 21.

An adhesive 12 is preferably formed on the sealing substrate 2.
The light transmitting substrate 13 is disposed via the b. Examples of the light transmitting substrate 13 include glass, polycarbonate, polymethylmethacrylate, polystyrene,
Resins such as hard vinyl chloride and polyolefin can be used. Further, as the adhesive 12b, the adhesive 1
Materials similar to 2a can be used.

A diffraction grating 6 is formed on the front surface of the light transmitting substrate 13, and a diffraction grating 14 is formed on the back surface (the surface facing the sealing substrate 2). This diffraction grating 6 and 14
Can be configured by, for example, periodic unevenness formed on the front surface (or the back surface) of the light transmitting substrate 13. The diffraction gratings 6 and 14 are arranged in the optical path of the laser light emitted from the semiconductor laser device 1.

A pedestal portion 19 for supporting the composite prism 18 is provided at the edge of the light transmitting substrate 13. The height of the pedestal portion 19 is set larger than the thickness of the Wollaston prism 16 of the composite prism 18, for example, 10 μm or more larger than the thickness of the Wollaston prism 16.

The composite prism 18 is arranged on the pedestal portion 19 of the light transmitting substrate 13. The composite prism 18 has a structure in which the polarization beam splitter 15, the Wollaston prism 16, and the reflector 17 are integrated.

The pedestal portion 19 of the light transmitting substrate 13 and the composite prism 18 are adhered to each other with an adhesive 12c. Further, as shown in FIG. 7, in addition to bonding the pedestal portion 19 of the light transmissive substrate 13, a portion other than the pedestal portion 19 of the light transmissive substrate 13 and the Wollaston prism 16 of the composite prism 18
And may be bonded via the adhesive 12d. The same material as the adhesive 12a can be used as the adhesives 12c and 12d.

A recess is formed on the surface of the compound prism 18 that is bonded to the pedestal 19 of the light transmitting substrate 13. The shape, size, and number of the recesses are not particularly limited, and may be the same as the recesses formed in the sealing substrate 2 in the first embodiment, for example. The method of forming the recess is not particularly limited,
For example, when glass is used, it can be performed by dicing using a dicing blade having a desired shape. When a resin is used, it can be formed by molding using a mold provided with a pattern having a desired shape.

Further, the collimator lens 3 and the objective lens 4 are arranged in the optical path of the laser beam to form a semiconductor laser device.

Next, the operation of the semiconductor laser device will be described with reference to FIG.

First, after the laser light emitted from the semiconductor laser device 1 passes through the sealing substrate 2, the diffraction grating 14
Is diffracted in a direction perpendicular to the paper surface of the drawing and transmitted through the light transmitting substrate. Subsequently, the light transmitted through the light transmission substrate is transmitted through the polarization beam splitter 15, is then converted from a divergent light beam into a parallel light beam by the collimator lens 3, and is condensed on the recording medium 5 by the objective lens 4. This light is recorded on the recording medium 5
After being reflected by the surface of, the light passes through the objective lens 4 and the collimator lens 3 as return light and enters the polarization beam splitter 15. The return light that has entered the polarization beam splitter 15 is split into the direction of the light transmission substrate 13 and the direction of the Wollaston prism 16.

Of the split return light, the light transmitting substrate 13
The light branched in the direction of is diffracted by the diffraction grating 6 and becomes −1st order diffracted light 7, 0th order diffracted light 8 and + 1st order diffracted light 9.
Then, the −1st order diffracted light 7 and the + 1st order diffracted light 9 are transmitted through the light transmitting substrate 13 and the sealing substrate 2, and are respectively received by the light receiving element 10a. On the other hand, of the return light split by the polarization beam splitter 15, the light split in the direction of the Wollaston prism 16 is reflected by the reflector 17, and then is converted into P-polarized light and S-polarized light by the Wollaston prism 16.
After being separated into polarized light, the light is transmitted through the light transmitting substrate 13 and the sealing substrate 2 and is received by the light receiving element 10b. In the figure, for the sake of simplicity, the −1st order diffracted light 7, 0
Illustration of diffracted lights other than the diffracted light 8 and the diffracted light +1 is omitted.

In the above description, the light transmitting substrate 1
Although an example in which a concave portion is formed on the surface of the composite prism 18 at the bonding portion between the composite prism 3 and the complex prism 18 is shown, a concave portion may be provided on the surface of the light transmitting substrate 13 as shown in FIG.
Further, as shown in FIG. 9, recesses may be provided on both the surface of the light transmitting substrate 13 and the surface of the composite prism 18.

Further, the light transmitting substrate 13 and the composite prism 18
In the bonded portion with, instead of the recessed portion as described above,
It is also possible to form a convex portion. In this case, the number, shape and size of the convex portions are not particularly limited.

Further, in the above description, the light transmitting substrate 1
An example was given in which a concave portion was formed on the surface of the member to be bonded at the bonding portion between 3 and the composite prism 18. However, the present invention is not limited to this, and at least one of the bonding portion between the light transmitting substrate 13 and the composite prism 18 and the bonding portion between the package 11 and the sealing substrate 2 has a concave portion on the surface of the bonded member. Should be formed. For example, as shown in FIG. 10, the member surface is a smooth surface at the bonding portion between the light transmitting substrate 13 and the composite prism 18, and the surface of the package 11 and the sealing substrate are at the bonding portion between the package 11 and the sealing substrate 2. It is also possible to form a recess on at least one of the two surfaces.

Further, in this embodiment, as shown in FIG. 11, it is possible to seal the package 11 by removing the sealing substrate 2 and adhering the light transmitting substrate 13 to the package 11.

[0048]

As described above, according to the first semiconductor laser device of the present invention, a semiconductor laser element for irradiating a recording medium with a laser beam, and the recording medium of the laser beam emitted from the semiconductor laser element. Diffraction grating for diffracting the return light at, a light receiving element for receiving the return light diffracted by the diffraction grating, a package for housing the semiconductor laser element and the light receiving element, and a sealing for sealing the package A semiconductor laser device comprising a substrate, wherein the package and the encapsulation substrate are adhered to each other via an adhesive, and at this adhering portion, the package and the encapsulation substrate are bonded to at least one of the adhering surfaces thereof. By forming the concave portion or the convex portion, it is possible to suppress the decrease in the adhesive strength between the package and the sealing substrate, which is caused by the positional deviation between the two. It is possible to suppress a change in academic performance.

Further, according to the second semiconductor laser device of the present invention, a semiconductor laser element for irradiating a recording medium with a laser beam and a return beam of the laser beam emitted from the semiconductor laser element on the recording medium are provided. A compound prism for splitting, a diffraction grating for diffracting the return light split by the compound prism, a light receiving element for receiving the return light diffracted by the diffraction grating, a semiconductor laser element and the light receiving element A semiconductor laser device including a package for forming the diffraction grating on the surface of a light transmitting substrate, and adhering the light transmitting substrate and the composite prism with an adhesive. By forming a concave portion or a convex portion on the bonding surface of at least one of the prism and the light transmitting substrate, the composite prism and the light transmitting Suppressing a decrease in bonding strength between the plate, it is possible to suppress a change in the optical properties due to the positional deviation between the two.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of a semiconductor laser device according to a first embodiment of the present invention.

FIG. 2 is a schematic view showing another example of the semiconductor laser device according to the first embodiment of the present invention.

FIG. 3 is a schematic diagram showing another example of the semiconductor laser device according to the first embodiment of the present invention.

FIG. 4 is a schematic view showing another example of the semiconductor laser device according to the first embodiment of the present invention.

FIG. 5 is a schematic diagram showing an example of a semiconductor laser device according to a second embodiment of the present invention.

FIG. 6 is a schematic view showing another example of the semiconductor laser device according to the second embodiment of the present invention.

FIG. 7 is a schematic view showing another example of the semiconductor laser device according to the second embodiment of the present invention.

FIG. 8 is a schematic diagram showing another example of the semiconductor laser device according to the second embodiment of the present invention.

FIG. 9 is a schematic diagram showing another example of the semiconductor laser device according to the second embodiment of the present invention.

FIG. 10 is a schematic diagram showing another example of the semiconductor laser device according to the second embodiment of the present invention.

FIG. 11 is a schematic view showing another example of the semiconductor laser device according to the second embodiment of the present invention.

FIG. 12 is a schematic view showing a conventional semiconductor laser device.

[Explanation of symbols]

1 Semiconductor laser device 2 Sealing substrate 3 Collimating lens 4 Objective lens 5 recording media 6, 14 Diffraction grating 7 -1st order diffracted light 80th-order diffracted light 9 + 1st order diffracted light 10, 10a, 10b Light receiving element 11 packages 12, 12a, 12b, 12c, 12d adhesive 13 Light transmission substrate 15 Polarizing beam splitter 16 Wollaston Prism 17 Reflector 18 compound prism 19 pedestal 20 substrates 21 reflective mirror

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5D119 AA36 FA05 FA28 FA30 JA10                       JA13                 5D789 AA36 FA05 FA28 FA30 JA10                       JA13                 5F073 AB25 BA04 EA29 FA02 FA29                 5F089 AA02 AB01 CA21 GA10

Claims (9)

[Claims] 1. A semiconductor laser element for irradiating a recording medium with a laser beam, a diffraction grating for diffracting a return beam of the laser beam emitted from the semiconductor laser element on the recording medium, and a diffraction grating diffracted by the diffraction grating. What is claimed is: 1. A semiconductor laser device comprising: a light receiving element that receives the return light; a package that houses the semiconductor laser element and the light receiving element; and a sealing substrate that seals the package. A semiconductor laser device, which is bonded to a substrate via an adhesive, and at this bonded portion, a concave portion or a convex portion is formed on the bonding surface of at least one of the package and the sealing substrate. . 2. The semiconductor laser device according to claim 1, wherein the diffraction grating is formed on the surface of the sealing substrate. 3. The semiconductor laser according to claim 1, further comprising a light transmitting substrate disposed between the recording medium and the sealing substrate, wherein the diffraction grating is formed on the surface of the light transmitting substrate. apparatus. 4. A composite prism disposed between the recording medium and the diffraction grating and configured to disperse the return light of the laser light emitted from the semiconductor laser element on the recording medium. The semiconductor laser device according to any one of 1 to 3. 5. A semiconductor laser element for irradiating a recording medium with laser light, a composite prism for dividing return light of the laser light emitted from the semiconductor laser element on the recording medium, and a composite prism A semiconductor laser device comprising a diffraction grating that diffracts the return light, a light receiving element that receives the return light diffracted by the diffraction grating, and a package that accommodates the semiconductor laser element and the light receiving element, The diffraction grating is formed on the surface of the light-transmitting substrate, the light-transmitting substrate and the composite prism are adhered to each other via an adhesive, and at this bonding portion, at least one of the composite prism and the light-transmitting substrate is bonded. A semiconductor laser device having a concave portion or a convex portion formed on a surface thereof. 6. The semiconductor laser device according to claim 5, wherein the package is sealed by being bonded to the light transmitting substrate via an adhesive. 7. The semiconductor laser according to claim 6, wherein a concave portion or a convex portion is formed on the bonding surface of at least one of the package and the light transmitting substrate at the bonding portion between the package and the light transmitting substrate. apparatus. 8. The semiconductor laser device according to claim 5, further comprising a sealing substrate for sealing the package. 9. The package and the sealing substrate are adhered to each other via an adhesive, and a concave portion or a convex portion is formed on an adhesive surface of at least one of the package and the sealing substrate at the adhesive portion. The semiconductor laser device according to claim 8.