JP6970532B2 - Semiconductor laser device - Google Patents

Description

The present invention relates to a semiconductor laser device that covers a semiconductor laser element with a cap.

The semiconductor laser device mounts a semiconductor laser element on a stem, and the semiconductor laser element is covered with a cap having a window portion. The semiconductor laser device is formed by laminating a semiconductor laminated film on a substrate, and emits laser light from an emitting portion of an end face of an active layer included in the semiconductor laminated film. The window portion of the cap faces the emitting portion, and the laser beam is taken out through the window portion. However, there is a problem that laser light is emitted from a region other than the active layer and ripple is generated in FFP (Far Field Pattern, far field image).

A conventional semiconductor laser device that reduces ripple is disclosed in Patent Document 1. In this semiconductor laser device, a first low refractive index layer, a first composition inclined portion, a light absorbing portion, a second composition inclined portion, and a second low refractive index layer are laminated in order in the n-side region or the p-side region adjacent to the active layer. doing.

The first low refractive index layer and the second low refractive index layer are formed of a low refractive index material such as AlGaN, and the light leaked from the active layer is confined between them. The light absorption unit has the minimum bandgap energy in the n-side region or the p-side region, and absorbs the light trapped between the first and second low refractive index layers to reduce the ripple.

The bandgap energy and the difference in the refractive index between the first composition inclined portion and the second composition inclined portion become larger as they are separated from the light absorbing portion. This prevents the ripple reduction effect from being weakened by scattering and reflection due to the difference in refractive index between the first and second low refractive index layers and the light absorbing portion.

Japanese Unexamined Patent Publication No. 2015-12153 (pages 3 to 8, FIG. 2)

However, according to the above-mentioned conventional semiconductor laser device, since a light absorbing portion or the like is provided in the semiconductor laminated film in order to reduce ripple, the processing is complicated and the number of steps of the semiconductor laser device increases. Therefore, there is a problem that the cost of the semiconductor laser apparatus provided with the semiconductor laser element increases.

An object of the present invention is to provide a semiconductor laser device capable of reducing ripple and cost.

In order to achieve the above object, the present invention has a semiconductor laser element that emits laser light from an emitting portion, a stem on which the semiconductor laser element is mounted, and a window portion facing the emitting portion. It is characterized in that the window portion has a first region and a second region having different transmission rates with respect to the laser beam.

Further, in the semiconductor laser apparatus having the above configuration, the first region is arranged in the central portion of the window portion, and the second region is arranged in the peripheral portion of the window portion, so that the transmission of the first region is transmitted. It is characterized in that the transmittance of the second region is lower than the rate.

Further, the present invention is characterized in that, in the semiconductor laser apparatus having the above configuration, the first region and the second region are arranged concentrically with respect to the optical axis of the laser beam.

Further, the present invention is characterized in that, in the semiconductor laser apparatus having the above configuration, an intermediate region having a transmittance lower than that of the first region and higher than that of the second region is provided between the first region and the second region. It is supposed to be.

Further, according to the present invention, in the semiconductor laser apparatus having the above configuration, the sealing member forming the window portion has a transparent substrate and a coating layer provided on the substrate for reducing the transmittance, and the second region thereof. It is characterized by arranging the coating layer.

Further, the present invention is characterized in that, in the semiconductor laser apparatus having the above configuration, a light absorber is arranged in the second region.

Further, the present invention is characterized in that, in the semiconductor laser apparatus having the above configuration, the second region is arranged in a range of 20 ° or more with respect to the optical axis of the laser beam.

According to the present invention, the window portion provided on the cap has a first region and a second region having different transmittances with respect to the laser light emitted from the semiconductor laser element. Therefore, the ripple of FFP can be reduced with a simple structure, and the cost of the semiconductor laser device can be reduced.

Perspective view which shows the semiconductor laser apparatus of 1st Embodiment of this invention. Front sectional view showing the semiconductor laser apparatus of the first embodiment of the present invention. Top view showing the sealing member of the semiconductor laser apparatus of the first embodiment of the present invention. Front sectional view showing a sealing member of the semiconductor laser apparatus of the first embodiment of the present invention. The figure which shows the light intensity distribution of FFP of the semiconductor laser apparatus of 1st Embodiment of this invention. The figure which shows the light intensity distribution of FFP of the semiconductor laser apparatus of the comparative example. Top view showing the sealing member of the semiconductor laser apparatus of the second embodiment of this invention. Front sectional view showing a sealing member of the semiconductor laser apparatus of the second embodiment of the present invention. The figure which shows the light intensity distribution of FFP of the semiconductor laser apparatus of 2nd Embodiment of this invention. Top view showing the sealing member of the semiconductor laser apparatus of the third embodiment of the present invention. Front sectional view showing a sealing member of the semiconductor laser apparatus of the third embodiment of the present invention. The figure which shows the light intensity distribution of FFP of the semiconductor laser apparatus of 3rd Embodiment of this invention.

<First Embodiment>
Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 show a perspective view and a front sectional view of the semiconductor laser device of the first embodiment. The semiconductor laser device 1 is formed in a CAN package type in which the semiconductor laser element 5 mounted on the stem 9 is covered with a cap 10.

The stem 9 has a metal base 8 such as a copper-based metal and leads 7a, 7b, and 7c. The base 8 is formed in a disk shape, and a plurality of through holes 8b penetrating in the vertical direction are provided. The leads 7a, 7b, and 7c are inserted into the through holes 8b and hermetically sealed via an insulator 8c such as glass.

A metal block 3 such as a copper-based metal is arranged on the upper surface 8a of the base 8 of the stem 9. The block 3 is arranged in contact with the lead 7b and has an installation surface 3a perpendicular to the upper surface 8a of the base 8. The submount 4 is adhered on the installation surface 3a, and the semiconductor laser element 5 is adhered on the submount 4. The submount 4 is formed of AlN, SiC, or the like having excellent hardness, heat resistance, and chemical stability and high thermal conductivity, and is connected to the block 3 by the wire 2.

The semiconductor laser device 5 is formed by laminating a semiconductor laminated film on the upper surface of a semiconductor substrate. The emitting portion 5a formed by the end faces of the active layer (not shown) included in the semiconductor laminated film is arranged upward. Electrodes (not shown) are formed on the upper surface of the semiconductor laminated film and the lower surface of the substrate, respectively. The electrodes on the upper surface of the semiconductor laminated film are connected to the leads 7a via the wire 2, and the electrodes on the lower surface of the substrate are arranged in contact with the submount 4. When power is supplied between the leads 7a and the leads 7b, a laser beam having a predetermined wavelength is emitted from the emitting unit 5a.

Further, a photodiode 6 is arranged on the upper surface 8a of the base 8. The photodiode 6 is connected to the lead 7c via the wire 2 and detects the intensity of the laser beam emitted downward from the facing surface of the emitting portion 5a of the semiconductor laser element 5. The intensity of the laser beam emitted from the emitting unit 5a is monitored by the detection result of the photodiode 6.

The cap 10 is formed of a cylindrical metal having an upper wall 10b and is arranged on the upper surface 8a of the base 8. The block 3 to which the semiconductor laser element 5 is attached and the photodiode 6 are covered with the cap 10. A circular opening 10a is provided at the center of the upper wall 10b of the cap 10. A sealing member 11 is provided on the lower surface of the upper wall 10b to bond the peripheral portion to the upper wall 10b and seal the opening 10a.

The region facing the opening 10a of the sealing member 11 forms a window portion 12 facing the exit portion 5a of the semiconductor laser element 5. The sealing member 11 is formed in a flat plate shape by glass, resin, or the like, and laser light is taken out from at least a part of the window portion 12. The lens may be formed by the sealing member 11.

3 and 4 show a top view and a front sectional view of the sealing member 11. The sealing member 11 has a transparent substrate 11a such as glass or resin, and coating layers 11d and 11e on which a coating agent is applied. The coating layers 11d and 11e are coated with coating agents having different transmittances for the laser light emitted from the emitting portion 5a (see FIG. 2). The coating layers 11d and 11e may be formed by film formation such as vacuum vapor deposition or sputtering.

The coating layer 11d provided at the center of the sealing member 11 is arranged on the optical axis of the semiconductor laser device 5. The coating layer 11e is formed in an annular shape arranged concentrically on the outer peripheral side of the coating layer 11d. At this time, the coating layer 11e is provided in a range of 20 ° or more with respect to the optical axis of the laser beam emitted from the emitting portion.

Further, the coating layer 11e has a lower transmittance for the laser light emitted from the emitting portion 5a (see FIG. 2) than the coating layer 11d. As a result, a region D1 (first region) having a high transmittance is formed in the central portion of the window portion 12, and a region D2 (second region) having a lower transmittance than the region D1 is formed in the peripheral portion of the window portion 12. NS.

In the present embodiment, the wavelength of the laser beam emitted from the emitting unit 5a is 450 nm. Further, the transmittance for the laser light having a wavelength of 450 nm is 90% or more in the region D1 and 10% or less in the region D2.

FIG. 5 is a diagram showing the light intensity distribution of the FFP of the semiconductor laser device 1. The vertical axis shows the light intensity, and the horizontal axis shows the angle (unit: °) of the laser light emitted from the emitting unit 5a with respect to the optical axis. The light intensity is normalized based on the maximum value. The angle with respect to the optical axis indicates an angle in a plane perpendicular to the installation surface 3a, and the positive side is a direction approaching the installation surface 3a.

Further, FIG. 6 shows the light intensity distribution of the FFP of the semiconductor laser device 1 of the comparative example. In the comparative example, the transmittance of the sealing member 11 is constant at 90% or more.

According to FIGS. 5 and 6, ripple R is generated while the angle with respect to the optical axis is +20 ° to +30 °. In this embodiment, since the region D2 is formed in the range where the absolute value of the angle with respect to the optical axis is 20 ° or more, the ripple R can be reduced as compared with the comparative example.

According to the present embodiment, the window portion 12 provided on the cap 10 has a region D1 (first region) and a region D2 (second region) having different transmittances with respect to the laser light emitted from the semiconductor laser element 5. Therefore, the ripple R of FFP can be reduced with a simple structure, and the cost of the semiconductor laser device 1 can be reduced.

Further, the region D1 is arranged in the central portion of the window portion 12, and the region D2 having a lower transmittance than the region D1 is arranged in the peripheral portion of the window portion 12. As a result, the ripple R generated in the peripheral portion of the window portion 12 can be reliably reduced.

Further, since the regions D1 and D2 are arranged concentrically with respect to the optical axis of the laser light, the orientation of the cap 10 is not restricted, and the man-hours of the semiconductor laser apparatus 1 can be reduced.

Further, the sealing member 11 is provided with a coating layer 11e on the transparent substrate 11a to reduce the transmittance, and the coating layer 11e is arranged in the region D2. Thereby, the region D2 having a low transmittance can be easily formed.

Further, since the region D2 is arranged in the range where the absolute value of the angle of the laser beam with respect to the optical axis is 20 ° or more, the ripple R can be surely reduced.

In the present embodiment, the coating layer 11d may be omitted and the transmittance of the region D1 may be the transmittance of the substrate 11a. Further, the coating layers 11d and 11e may be formed with the same coating agent, and the coating layer 11e may be formed thicker than the coating layer 11d to have different transmittances. Further, the coating layers 11d and 11e may be omitted, and the substrates 11a having different transmittances may be joined concentrically to form the region D1 and the region D2.

<Second Embodiment>
Next, FIGS. 7 and 8 are a top view and a front sectional view showing the sealing member 11 of the semiconductor laser device 1 of the second embodiment. For convenience of explanation, the same parts as those in the first embodiment shown in FIGS. 1 to 4 are designated by the same reference numerals. In this embodiment, the sealing member 11 is provided with a light absorber. Other parts are the same as those in the first embodiment.

The sealing member 11 is formed by joining a circular substrate 11b made of glass, resin, or the like and an annular substrate 11c concentrically. The substrate 11b provided at the center of the sealing member 11 is arranged on the optical axis of the semiconductor laser element 5. The substrate 11c is arranged on the outer peripheral side of the substrate 11b, and the peripheral portion of the substrate 11c is adhered to the lower surface of the upper wall 10b of the cap 10. At this time, the substrate 11c is provided in a range of 20 ° or more with respect to the optical axis of the laser beam emitted from the emitting portion 5a (see FIG. 2).

The substrate 11b is formed of a transparent material that transmits light. The substrate 11c is formed of a light absorber. The substrate 11c of the light absorber is formed by kneading a coloring material (pigment-based absorbent dye, dye-based absorbent dye, etc.) with glass or resin. The transparent member may be coated with a coloring material of a light absorber to form the substrate 11c.

As a result, a region D1 that transmits light at a predetermined transmittance is formed in the central portion of the window portion 12, and a region D2 that has a lower transmittance than the region D1 and absorbs light is formed in the peripheral portion of the window portion 12. .. In the present embodiment, the wavelength emitted from the emitting unit 5a is 450 nm, and the transmittance of the region D1 with respect to the laser light having a wavelength of 450 nm is 90% or more.

FIG. 9 is a diagram showing the light intensity distribution of the FFP of the semiconductor laser device 1. The vertical axis shows the light intensity, and the horizontal axis shows the angle (unit: °) of the laser light emitted from the emitting unit 5a with respect to the optical axis. The light intensity is normalized based on the maximum value. The angle with respect to the optical axis indicates an angle in a plane perpendicular to the installation surface 3a, and the positive side is a direction approaching the installation surface 3a. According to FIG. 9, the ripple R shown in FIG. 6 can be prevented.

According to this embodiment, the same effect as that of the first embodiment can be obtained. Further, since the substrate 11c of the light absorber is arranged in the region D2, the ripple R can be reliably prevented. Further, by appropriately arranging the region D2 formed by the light absorber, the ellipticity at the time of light projection by the semiconductor laser device 1 can be changed.

Even if the substrate 11c has light transmission property, if the opening portion 10a of the cap 10 is formed to have a small diameter, it is possible to block light in a region having a large angle with respect to the optical axis. However, according to this configuration, the light transmitted through the sealing member 11 and reflected on the lower surface of the upper wall 10a of the cap 10 is reflected inside the cap 10 and leaks from the window portion 12.

In this embodiment, since the peripheral portion of the window portion 12 is formed by the substrate 11c of the light absorbing material, it is possible to reduce the light reflected from the lower surface of the upper wall 10a and leaking from the window portion 12. Further, since the peripheral portion of the substrate 11c of the light absorber is adhered to the lower surface of the upper wall 10a of the cap 10, the light reflected on the lower surface of the upper wall 10a can be further reduced.

<Third Embodiment>
Next, FIGS. 10 and 11 are a top view and a front sectional view showing the sealing member 11 of the semiconductor laser device 1 of the third embodiment. For convenience of explanation, the same parts as those in the first embodiment shown in FIGS. 1 to 4 are designated by the same reference numerals. In this embodiment, an intermediate region D3 is provided between the region D1 and the region D2. Other parts are the same as those in the first embodiment.

The intermediate region D3 is formed by a coating layer 11f coated with a coating agent on the substrate 11a. The coating layer 11f is formed in an annular shape arranged concentrically on the outer peripheral side of the coating layer 11d. The coating layer 11e is formed in an annular shape arranged concentrically on the outer peripheral side of the coating layer 11f.

Further, the coating layer 11f has a lower transmittance for the laser light emitted from the emitting portion 5a (see FIG. 2) than the coating layer 11d and higher than the coating layer 11e. As a result, an intermediate region D3 having a transmittance lower than that of the region D1 and higher than that of the region D2 is formed between the region D1 having a high transmittance and the region D2 having a low transmittance.

In the present embodiment, the transmittance of the intermediate region D3 with respect to the laser light having a wavelength of 450 nm emitted from the emitting unit 5a is set to 50%.

FIG. 12 is a diagram showing the light intensity distribution of the FFP of the semiconductor laser device 1. The vertical axis shows the light intensity, and the horizontal axis shows the angle (unit: °) of the laser light emitted from the emitting unit 5a with respect to the optical axis. The light intensity is normalized based on the maximum value. The angle with respect to the optical axis indicates an angle in a plane perpendicular to the installation surface 3a, and the positive side is a direction approaching the installation surface 3a.

According to FIG. 12, the ripple R can be reduced as in FIG. 5 described above. Further, the full width at half maximum of the laser beam can be made smaller than that of the first embodiment to reduce the spreading angle.

Since the semiconductor laser element 5 has a large spread angle of emitted light, the semiconductor laser device 1 for applications such as a laser pointer is modularized integrally with a condenser lens that reduces the spread angle. In this embodiment, since the spread angle of the emitted light of the semiconductor laser device 1 can be reduced, the condenser lens can be omitted at the time of modularization. Therefore, it is possible to reduce the size and cost of the module provided with the semiconductor laser device 1.

By further subdividing the intermediate region D3 according to the transmittance, the light intensity of the laser beam emitted from the semiconductor laser device 1 can be brought closer to the Gaussian distribution.

According to this embodiment, the same effect as that of the first embodiment can be obtained. Further, since the intermediate region D3 is provided, the spread angle of the laser beam can be reduced, and the module provided with the semiconductor laser device 1 can be miniaturized and the cost can be reduced.

In the first to third embodiments, the region D2 formed in an annular shape may be provided in a range where the ripple R is generated, and may be formed in another shape. For example, the arched region D2 may be formed only on the positive side at an angle with respect to the optical axis.

According to the present invention, it can be used for a CAN package type semiconductor laser device.

1 Semiconductor laser device 3 Block 3a Installation surface 4 Submount 5 Semiconductor laser element 5a Ejector 6 Photodiode 7a, 7b, 7c Lead 8 Base 9 Stem 10 Cap 10a Opening 10b Upper wall 11 Sealing member 11a, 11b, 11c Substrate 11d, 11e, 11f Coating layer 12 Window part D1 area D2 area D3 Intermediate area R Ripple

Claims (4)

A semiconductor laser element that emits laser light from an emitting portion, a stem on which the semiconductor laser element is mounted, and a cap having a window portion facing the emitting portion and covering the semiconductor laser element are provided, and the window portion has the window portion. It has a first region and a second region having different transmission rates with respect to the laser beam.
The first region is arranged in the central portion of the window portion, and the angle of the laser beam emitted from the emission portion of the peripheral portion of the window portion with respect to the optical axis causes ripple in the far-field image. The second region is arranged in an angle range, and the transmittance of the second region is lower than the transmittance of the first region.
A semiconductor laser device characterized in that a laser beam emitted from the emitting portion passes through the first region and the second region and is emitted from the window portion. The semiconductor laser apparatus according to claim 1, wherein the first region and the second region are arranged concentrically with respect to the optical axis of the laser beam. The first or second aspect of the present invention, wherein an intermediate region having a transmittance lower than that of the first region and higher than that of the second region is provided between the first region and the second region. Semiconductor laser device. A claim characterized in that the sealing member forming the window portion has a transparent substrate and a coating layer provided on the substrate for reducing the transmittance, and the coating layer is arranged in the second region. The semiconductor laser apparatus according to claim 1 or 2.

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