WO2018021414A1

WO2018021414A1 - Eye-safe light source and electronic device

Info

Publication number: WO2018021414A1
Application number: PCT/JP2017/027060
Authority: WO
Inventors: 伊藤　晋
Original assignee: シャープ株式会社
Priority date: 2016-07-29
Filing date: 2017-07-26
Publication date: 2018-02-01

Abstract

An eye-safe light source, wherein light emission efficiency is improved while orientation characteristics are adjusted. The eye-safe light source (1) is provided with a package (108), a semiconductor laser (100) that emits laser light (114) from a right light-emitting end surface (100r), and a wire (110) joined to the semiconductor laser (100). The semiconductor laser (100) is joined to the package (108) so that the laser light (114) is emitted parallel to a reference surface of the package (108). The package (108) has a reflective surface (116) for reflecting the laser light (114). The reflection surface (116) is provided so as to face the right light-emitting end surface (100r), and comprises an aggregate of multi-level inclined surfaces, the inclination angles of the inclined surfaces differing so as to be greater approaching the emission end part of the laser light (114).

Description

Eye-safe light source and electronic equipment

The present invention relates to an eye-safe light source that has been made eye-safe and an electronic device including the same.

In recent years, wireless optical communication modules such as IrDA (Infrared Data Association), optical sensor modules, and the like have been widely installed in electronic devices such as mobile phones and laptop computers. For example, Patent Document 1 discloses an optical proximity sensor (reflective optical coupling device) mounted on a mobile phone.

In such portable electronic devices, since the power source is a battery, it is strongly desired to reduce the power consumption of the mounted module. Moreover, also in the wireless optical communication equipment using illumination, reduction of power consumption is desired from the viewpoint of energy efficiency. In the wireless optical communication module, the optical sensor module, and the like, since the light source that mainly emits light consumes power, it is desired to reduce the power consumption of the light source.

On the other hand, light sources for wireless optical communication and optical sensoring, etc. must ensure safety (eye-safe) for human eyes. Moreover, in order to use it for wireless optical communication, optical sensing, etc., it is necessary to arrange light distribution.

For example, Patent Documents 2 to 4 disclose eye-safe light sources in which laser light emitted from a semiconductor laser is made eye-safe. In the eye-safe light sources disclosed in Patent Documents 2 to 4, the laser light passes through the light scattering layer, so that the spot diameter of the laser light is widened and the laser light is made eye-safe. Further, Patent Document 5 discloses a lens shape that adjusts light from an eye-safe light source in which such laser light is made eye-safe into a light intensity distribution suitable for wireless optical communication and adjusts light distribution characteristics.

Japanese Patent Publication “JP 2011-96724 (May 12, 2011)” Japanese Patent Gazette “Patent No. 4014425 (issued on November 28, 2007)” Japanese Patent Publication “Patent No. 5046538 (issued on October 10, 2012)” Japanese Patent Publication “JP 2007-266484 A (published Oct. 11, 2007)” Japanese Patent Publication “Japanese Patent Laid-Open No. 2005-142447 (published on June 02, 2005)”

However, in the conventional techniques such as Patent Documents 2 to 4, multiple light scattering occurs while passing through the light scattering layer. Since light absorption occurs due to multiple light scattering, there is a problem that the efficiency of extracting light (light emission efficiency) with respect to power consumption decreases. Further, the alignment characteristics and polarization characteristics of the laser beam are lost due to multiple scattering.

Also, when a semiconductor laser is bonded to a substrate without a submount, laser light emitted so as to spread from the semiconductor laser hits the substrate. For this reason, a laser beam cannot spread and eye safety performance falls. Even if the submount is used, if the semiconductor laser is bonded to the inside of the submount, the shadow of the submount is generated in the virtual light source, and the light emission efficiency is lowered.

As described above, the conventional eye-safe light source has a problem that the alignment characteristics are lost due to the eye-safe and a problem that the light emission efficiency is low.

The present invention has been made in view of the above-described problems, and an object thereof is to improve luminous efficiency while adjusting alignment characteristics in an eye-safe light source.

In order to solve the above problems, an eye-safe light source according to one embodiment of the present invention includes a substrate and a semiconductor laser that emits laser light from a light emitting end surface, and the semiconductor laser uses the laser light as a reference of the substrate. The substrate is bonded to the substrate so as to be emitted in a horizontal direction with respect to the surface, and the substrate has a reflection surface that reflects the laser light, and the reflection surface is provided to face the light emitting end surface. In addition, it is made up of an assembly of multi-stage inclined surfaces, and the inclination angle of the inclined surfaces is different so as to be closer to the laser light emitting end.

According to one aspect of the present invention, the eye-safe light source has the effect of improving the light emission efficiency while adjusting the alignment characteristics. In addition, the eye-safe light source can be reduced in thickness and size.

2A and 2B are diagrams illustrating a schematic configuration of the periphery of the semiconductor laser of the light source according to the first embodiment of the present invention, in which FIG. 1A is a top view of the resin portion seen through, and FIG. 2B is a cross-sectional view taken along line AA in FIG. (C) is a cross-sectional view taken along the line BB of (a), (d) is a cross-sectional view taken along the line CC of (a), and (e) is a perspective view of the resin portion. (F) is a cross-sectional view taken along the line AA schematically showing the light emission state of (b). In the light source shown in FIG. 1, the reflection of the laser beam by the reflecting surface is shown, (a) is reflected by the middle inclined surface, (b) is reflected by the upper inclined surface, and (c) is by the lower inclined surface. It is sectional drawing which shows reflection, respectively. It is sectional drawing which shows collectively the breadth of the laser beam reflected by the said middle stage inclined surface, the said upper stage inclined surface, and the said lower stage inclined surface. It is sectional drawing which shows reflection of the laser beam by the reflective surface of the comparative example with respect to the reflective surface shown in FIG. It is sectional drawing which shows reflection of the laser beam by the reflective surface of the other comparative example with respect to the reflective surface shown in FIG. It is a graph which shows the light distribution characteristic of the model light source used in order to demonstrate the effect of the reflective surface shown in FIG. FIG. 6A is a graph showing the light intensity distributions of the light from the model light source having the light distribution characteristics shown in FIG. 6 and the light reflected by the reflection surface shown in FIG. 2 and the light reflected by the reflection surfaces of the two comparative examples. (B) is a graph showing an enlarged main part of (a). The light intensity distribution of the reflected light from the reflection surface of the above-mentioned middle-stage inclined surface, the reflected light from the upper-stage inclined surface, the reflected light from the lower-stage inclined surface, the combined light of these reflected lights, and the reflective surface of the comparative example shown in FIG. It is a graph to show. (A) is a perspective view which shows typically the radiation | emission of the light from the semiconductor laser as a model light source mounted on the submount, (b) is shown to (a) mounted in the package shown in FIG. It is a perspective view which shows typically radiation | emission of the reflected light of the light from a semiconductor laser. (A) is a graph which shows the typical light distribution characteristic of the laser beam shown to (a) of FIG. 9, (b) is the typical light distribution characteristic of the reflected light shown to (b) of FIG. (C) is a graph showing typical light distribution characteristics obtained when the reflected light shown in (b) of FIG. 9 is further passed through the light scattering layer, and (d) is It is a graph which shows the typical light distribution characteristic of the reflected light by the reflective surface (parabolic reflector) which consists of a paraboloid as a comparative example. It is a graph which shows the light distribution characteristic containing the spike-shaped processus | protrusion obtained when the reflected light by the said parabolic reflector is further passed through a light-scattering layer. It is sectional drawing which expands and shows a part of eye safe light source which concerns on the modification of Embodiment 1. FIG. FIG. 7 is a diagram showing a schematic configuration around a semiconductor laser of an eye-safe light source according to another modification of the first embodiment, (a) is a top view through which a resin portion is seen, and (b) is A1-A1 of (a). It is arrow sectional drawing, (c) is B1-B1 arrow sectional drawing of (a). FIG. 5 is a diagram showing a schematic configuration around a semiconductor laser of an eye-safe light source according to Embodiment 2 of the present invention, where (a) is a top view seen through a resin portion, and (b) is a view taken along a DD arrow in (a). FIG. 3C is a cross-sectional view taken along the line EE in FIG. 4A, and FIG. 4D is a cross-sectional view taken along the line FF in FIG. (A) is sectional drawing which shows the light emission state of the eye safe light source shown in FIG. 14, (b) is a side view of the said eye safe light source, (c) is a side view of the said eye safe light source in the light emission state. (A) is a perspective view which shows typically the radiation | emission of the light from the semiconductor laser as a model light source mounted on the submount, (b) is shown to (a) mounted in the package shown in FIG. It is a perspective view which shows typically the radiation of the reflected light of the light from a semiconductor laser, (c) is a schematic diagram which shows the state through which the reflected light shown to (b) passed the light-scattering layer. FIG. 10 is a diagram illustrating a schematic configuration around a semiconductor laser of an eye-safe light source according to a modification of the second embodiment, where (a) is a top view seen through a resin portion, and (b) is a view taken along arrows D1-D1 in (a). It is sectional drawing, (c) is E1-E1 arrow sectional drawing of (a). FIG. 10 is a diagram illustrating a schematic configuration around a semiconductor laser of an eye-safe light source according to another modification of the second embodiment, wherein (a) is a top view of the resin portion seen through, and (b) is D2-D2 of (a). It is arrow sectional drawing, (c) is E2-E2 arrow sectional drawing of (a). It is a figure which shows schematic structure of the semiconductor laser periphery of the eye safe light source which concerns on Embodiment 3 of this invention, (a) is the top view which saw through the resin part, (b) is GG arrow of (a). (C) is a cross-sectional view taken along the line HH of (a), (d) is a cross-sectional view taken along the line II of (a), and (e) is a cross-sectional view of (a). It is a JJ arrow sectional drawing, (f) is KK arrow sectional drawing of (a). (A) is sectional drawing which shows the light emission state of the eye safe light source shown in FIG. 19, (b) is a side view of the said eye safe light source, (c) is a side view of the said eye safe light source in a light emission state. (A) is a graph showing the light distribution characteristics when the inclination angle of the central axis of the reflecting surface shown in (b) of FIG. 20 is 3 °, and (b) is shown in (b) of FIG. It is a graph which shows the light distribution characteristic in case the inclination angle of the central axis of a reflective surface is 5 degrees. (A) is a figure which shows the typical mapping of the light intensity at the time of projecting the light of the light distribution characteristic shown to (a) of FIG. 21, (b) is the light distribution characteristic shown to (b) of FIG. It is a figure which shows the schematic mapping of the light intensity at the time of projecting the light of (c), (c) is a schematic mapping of the light intensity at the time of projecting the light of the light distribution characteristic shown in (b) of FIG. FIG. As a comparative example for the mapping shown in FIG. 22, mapping of light intensity when light having a light distribution characteristic shown in FIG. 10D obtained by using a reflecting surface (parabolic reflector) made of a paraboloid is projected. FIG. FIG. 5 is a diagram showing a schematic configuration around a semiconductor laser of a light source according to a fourth embodiment of the present invention, (a) is a top view seen through a resin portion, and (b) is a cross-sectional view taken along line LL in (a). (C) is a cross-sectional view taken along line MM in (a), and (d) is a cross-sectional view taken along line NN in (a). (A) is sectional drawing which shows the light emission state of the eye safe light source shown in FIG. 24, (b) is a side view of the said eye safe light source, (c) is a side view of the eye safe light source of Embodiment 1 in a light emission state. It is. FIG. 6 is a diagram illustrating a schematic configuration around a semiconductor laser of a light source according to a fifth embodiment of the present invention, wherein (a) is a top view seen through a resin portion, and (b) is a cross-sectional view taken along line OO in (a). (C) is a cross-sectional view taken along the line PP of (a), (d) is a cross-sectional view taken along the line QQ of (a), and (e) is a cross-sectional view taken along the line R-- It is R arrow sectional drawing, (f) is SS arrow sectional drawing of (a). (A) is sectional drawing which shows the light emission state of the eye safe light source shown in FIG. 26, (b) is a side view of the said eye safe light source, (c) is that the central axis of a reflective surface inclines with respect to an optical axis. It is a side view of the eye safe light source in the light emission state which is not. FIG. 9 is a diagram showing a schematic configuration around a semiconductor laser of a light source according to a sixth embodiment of the present invention, (a) is a top view seen through a resin portion, and (b) is a cross-sectional view taken along the line TT of (a). It is a figure and (c) is the U arrow directional cross-sectional view of (a). FIG. 10 is a diagram showing a schematic configuration around a semiconductor laser of another light source according to Embodiment 6 of the present invention, (a) is a top view seen through a resin portion, and (b) is a VV arrow in (a). It is a sectional view taken along line (c), and is a sectional view taken along line XX in (a). It is a figure which shows schematic structure of the optical sensor which concerns on Embodiment 7 of this invention.

Embodiment 1
Hereinafter, Embodiment 1 of the present invention will be described in detail with reference to FIG.

FIG. 1 is a diagram showing a schematic configuration around a semiconductor laser 100 of an eye-safe light source 1 according to Embodiment 1 of the present invention. FIG. 1A is a top view of the resin portion 106 seen through. FIG. 1B is a cross-sectional view taken along the line AA in FIG. FIG. 1C is a cross-sectional view taken along the line BB in FIG. 1D is a cross-sectional view taken along the line CC of FIG. 1A, and FIG. 1E is a bottom view of the resin portion 106 not seen through. FIG. 1F is a cross-sectional view taken along the line AA schematically showing the light emission state of FIG. Hereinafter, the direction in which the eye-safe light source 1 emits light will be described as above. However, the direction of the eye-safe light source 1 at the time of manufacture and use is not limited.

As shown in FIG. 1, the eye-safe light source 1 includes a semiconductor laser 100 that emits laser light 114 mainly from the right light emitting end surface 100r of the left and right sides, a submount 102 on which the semiconductor laser 100 is mounted, and a metal lead frame (hereinafter referred to as “a” A package (substrate) 108 having a lead frame 104 (not shown) and a resin portion 106, and a wire 110 are provided. The eye safe light source 1 is a surface mount type. The eye-safe light source 1 is provided with a mark 112 so that the directions of the anode and the cathode can be seen.

The optical axis 118 (symmetry axis) indicates the direction in which the eye-safe light is emitted from the eye-safe light source 1, and is perpendicular to the upper surface of the lead frame 104 and the upper surface of the package 108.

(package)
The package 108 is a member in which the periphery of the lead frame 104 is partially covered (packaged) with the resin portion 106. A concave portion 120 having an opening (opening portion) 124 is formed in the resin portion 106, and a part of the upper surface (exposed portion 122) of the lead frame 104 is exposed from the concave portion 120. The opening 124 serves as an emission end of the laser beam 114 and opens on the upper surface of the package 108. The package 108 houses the semiconductor laser 100 inside the recess 120.

The lead frame 104 is obtained by punching and plating a thin metal plate such as a copper-based alloy and is excellent in thermal conductivity, heat dissipation, mechanical strength, and electrical conductivity. Since the exposed portion 122 is electrically and thermally connected to the semiconductor laser 100 on the top surface of the lead frame 104, it is not covered with the resin portion 106 as shown in FIGS. Are exposed in the recess 120. Most of the lower surface of the lead frame 104 is exposed downward from the resin portion 106 to dissipate heat, as shown in FIGS. The lead frame 104 is electrically connected to the outside through lead terminals not shown in FIG. Alternatively, the lead frame 104 may be electrically connected to the outside through the lower surface of the lead frame 104 exposed from the resin portion 106.

The lead frame 104 includes a cathode portion 104 c connected to the cathode of the semiconductor laser 100 and an anode portion 104 a connected to the anode of the semiconductor laser 100. The cathode portion 104 c and the anode portion 104 a are joined by the resin portion 106 and insulated by the resin portion 106. In addition, the submount 102 on which the semiconductor laser 100 is mounted is bonded onto the exposed portion 122 of the cathode portion 104c. It should be noted that the size of the cathode portion 104c and the anode portion 104a and the arrangement with respect to the semiconductor laser 100 may be reversed. The top surface of the lead frame 104 is parallel to the bottom surface (reference surface) of the package 108.

The resin forming the resin portion 106 is a white thermoplastic resin including a light scatterer that scatters the laser light 114, and is a resin often used for LED (Light Emitting Diode) light sources. The resin portion 106 may be formed of, for example, polycyclohexylene dimethylene terephthalate (PCT) resin or polyphthalamide (PPA) resin. In addition, although white resin was used in order to improve a reflectance, you may use resin of another color, such as red, according to the wavelength of the laser beam 114 and the use of the eye safe light source 1. Further, although a thermoplastic resin is used, a resin having another property such as thermosetting or photo-curing may be used depending on the manufacturing method of the package 108.

Although not shown in FIG. 1, a control element for controlling light emission of the semiconductor laser 100 may be bonded to the lead frame 104 and sealed with the resin portion 106. Further, other semiconductor elements may be sealed inside the package 108 by the resin portion 106.

The mark 112 is formed as a depression of a right isosceles triangle on the resin portion 106 on the upper surface of the package 108. Thereby, since the mark 112 can be formed simultaneously with the molding of the resin portion 106, it is possible to eliminate an error in attaching the mark 112. Note that the mark 112 is not necessarily provided.

Since the lead frame 104 is made of metal, it has excellent thermal conductivity and heat dissipation. Therefore, by joining the submount 102 on which the semiconductor laser 100 is placed to the exposed portion 122 of the lead frame 104, the heat generated by the semiconductor laser 100 can be quickly radiated. Therefore, the eye-safe light source 1 is excellent in heat dissipation.

Since the metal lead frame 104 reinforces the resin portion 106, the package 108 including the metal lead frame 104 is superior in mechanical strength to a package not including the metal lead frame 104. For this reason, even if the package 108 is thinned, the mechanical strength required for the eye-safe light source 1 can be achieved, and the eye-safe light source 1 can be thinned.

(Concave)
The recess 120 includes a first recess 1201 having a substantially inverted quadrangular frustum shape and a second recess 1202 having a semicircular substantially multi-stage inverted truncated cone shape. First recess 1201 is formed to expose semiconductor laser 100, submount 102, and wire 110. On the other hand, the second recess 1202 is formed on the side surface on the side from which the laser beam 114 is emitted among the four side surfaces forming the first recess 1201.

The inside of the recess 120 is a cavity, and the opening 124 of the recess 120 is opened without being closed. Therefore, there is nothing in particular in the vicinity of the light emitting end face (right light emitting end face 100r) of the semiconductor laser 100, and air is present.

Therefore, there is no substance such as a light scatterer that generates heat by absorbing the laser beam 114 in the vicinity of the light emitting end face of the semiconductor laser 100. Since no heat is generated in this way, the material in the vicinity of the light emitting end face of the semiconductor laser 100 is not thermally damaged. Therefore, the function of the eye-safe light source 1 does not deteriorate due to the modification of the substance in the vicinity of the light emitting end face. That is, it is possible to prevent the eye-safe property and the light emission efficiency of the eye-safe light source 1 from being lowered due to continuous use and long-time use. Thereby, the service life of the eye-safe light source 1 is extended. Further, in the eye-safe light source 1, there is neither a material that is thermally damaged nor a material that is optically damaged in the recess 120, so that the material in the vicinity of the light emitting end face of the semiconductor laser 100 is thermally optically optical. Will not be damaged.

Note that portions other than the light emitting end face of the semiconductor laser 100 may be covered with a resin or the like. The light emitting end face of the semiconductor laser 100 may be covered as long as it is a substance that does not generate heat by absorbing the laser light 114, such as a transparent resin that does not include a light scatterer.

On the other hand, in the conventional technique in which a semiconductor laser is sealed with a sealing resin including a light scatterer, the light scatterer included in the sealing resin absorbs the laser light and generates heat. For this reason, there exists a problem that a light-scattering body and sealing resin modify | denature especially in the light emission end surface vicinity where a light density becomes high. The same applies to the prior art in which sealing is performed with a liquid containing a light scatterer instead of a resin.

Also, the inside of the recess 120 is hollow, and the semiconductor laser 100 inside the recess 120 is exposed without being sealed with resin or gas. Furthermore, since the semiconductor laser 100 is bonded to the lead frame 104 via the submount 102, the semiconductor laser 100 can be expanded and contracted according to temperature changes. Thus, it is preferable that the semiconductor laser 100 can be expanded and contracted from the viewpoint of reducing the mechanical load.

The semiconductor laser 100 generates heat when it emits light. For this reason, when the semiconductor laser 100 is resin-sealed, stress is generated due to a difference in thermal expansion coefficient between the semiconductor laser 100 and the sealing resin, and a mechanical load is applied to the semiconductor laser 100 and the sealing resin. . Although the result of such a mechanical load has not been clarified, there is a concern that some defect may occur. Therefore, it is preferable not to resin-seal the semiconductor laser 100 so that stress is not generated. Further, even when the semiconductor laser 100 is sealed with an inert gas, the sealing gas expands due to the heat generated by the semiconductor laser 100, and stress is generated on the package 108. A load is added. For this reason, it is preferable not to hermetically seal the semiconductor laser 100.

(Submount and semiconductor laser)
As shown in FIG. 1A, the submount 102 is joined to the center of the bottom of the recess 120 of the package 108 and joined to the exposed portion 122 of the cathode portion 104 c of the lead frame 104. The submount 102 is electrically connected to the anode of the semiconductor laser 100, and is electrically connected to the anode portion 104 a of the lead frame 104 via the wire 110. The submount 102 is thermally connected to the semiconductor laser 100 and thermally connected to the cathode portion 104 c of the lead frame 104.

The semiconductor laser 100 is an infrared semiconductor laser that emits laser light having a wavelength longer than 700 nm. The semiconductor laser 100 emits laser light 114 mainly from the right light emitting end face 100r as shown in FIG. Therefore, the left and right end faces and the vicinity of the end faces of the resonator formed in the semiconductor laser 100 are optically asymmetric. For example, it is conceivable to use a semiconductor laser having an asymmetrical emission ratio of 5 to 95 on the left and right sides of the left and right light emitting end faces. An optical window structure may be formed in the vicinity of the light emitting end face.

The semiconductor laser 100 is mounted on the submount 102 so that the right light emitting end face 100r protrudes from the submount 102 as shown in FIGS. 1 (a), (b), and (f). Since the right light emitting end face 100r protrudes, the laser beam 114 is emitted toward the resin portion 106 without being blocked by the submount 102.

The semiconductor laser 100 is bonded to the lead frame 104 via the submount 102 so that the optical axes of the laser beams 114 are aligned in parallel with the upper surface of the lead frame 104 ((f) in FIG. 1). That is, the semiconductor laser 100 is mounted on the lead frame 104 so that the resonator of the semiconductor laser 100 is parallel to the upper surface of the lead frame 104 and the active layer of the semiconductor laser 100 is parallel to the upper surface of the lead frame 104. On the other hand, it is placed flat.

Among infrared rays, visible light, and ultraviolet rays, infrared rays have the lowest energy per photon. For this reason, when the resin portion 106 is formed of a resin (PCT resin or PPA resin or the like) that is usually used for resin packaging of blue LEDs and white LEDs, the semiconductor laser 100 is an infrared laser. Therefore, in this case, the resin portion 106 has sufficient durability and long-term reliability with respect to the laser beam 114 emitted from the semiconductor laser 100. The semiconductor laser 100 may be a visible light semiconductor laser that emits laser light having a wavelength in the visible light region, or may be an ultraviolet semiconductor laser that emits laser light having a wavelength in the ultraviolet region. Good.

Since the right light emitting end face 100r protrudes from the submount 102, the laser light 114 emitted from the semiconductor laser 100 is emitted toward the resin portion 106 without being blocked by the submount 102. Therefore, since the shadow of the submount 102 does not occur, the light extraction efficiency of the eye-safe light source 1 with respect to the laser light 114 can be improved. Furthermore, the power consumption of the electronic device provided with the eye safe light source 1 and the eye safe light source 1 can be suppressed by improving the light extraction efficiency.

The semiconductor laser 100 is bonded to the upper surface of the lead frame 104 through the submount 102. For this reason, the laser beam 114 emitted from the semiconductor laser 100 can travel straight to the lower side (lead frame 104 side) while spreading similarly to the upper side (opening 124 side) without being blocked by the submount 102. Yes ((f) in FIG. 1). Since the laser beam 114 travels straight in the same manner on the upper side and the lower side, it becomes easy to predictably control the light distribution of the laser beam 114 on the reflection surface 116 made of the resin portion 106.

The semiconductor laser 100 is mounted flat on the lead frame 104. For this reason, the depth of the recessed part 120 (distance between the upper base and the lower bottom of the recessed part 120) can be made shallow. Therefore, the package 108, that is, the eye-safe light source 1 can be reduced in thickness and size. Further, the optical path length until the laser beam 114 reaches the reflecting surface 116 can be increased without changing the depth of the recess 120. Thus, since the optical path length can be secured not in the thickness direction of the package 108 (direction parallel to the optical axis 118) but in the surface direction of the package 108 (direction perpendicular to the optical axis 118), the eye-safe light source 1 is made thin. it can.

(Wire)
The wire 110 is a gold wire and is a power line that supplies power for driving the semiconductor laser 100.

A single wire 110 connects the cathode of the semiconductor laser 100 and the cathode portion 104c of the lead frame 104. The single wire 110 extends from the semiconductor laser 100 to the front side (lower side in FIG. 1A), and is emitted in a horizontal direction with respect to the upper surface of the lead frame 104 when viewed from the direction of the optical axis 118. The laser beam 114 is substantially orthogonal to the optical axis.

Another wire 110 connects the submount 102 connected to the anode of the semiconductor laser 100 and the anode portion 104 a of the lead frame 104. The other single wire 110 extends from the submount 102 to the rear side (upper side in FIG. 1A), and is emitted in parallel to the upper surface of the lead frame 104 when viewed from the direction of the optical axis 118. The laser beam 114 is substantially orthogonal to the optical axis.

That is, each of the wires 110 is substantially orthogonal to the laser beam 114 when viewed from above. For this reason, the laser beam 114 is not blocked by the wire 110. Therefore, since the shadow of the wire 110 does not occur, the light extraction efficiency of the eye-safe light source 1 with respect to the laser beam 114 can be improved. Furthermore, the power consumption of the electronic device provided with the eye safe light source 1 and the eye safe light source 1 can be suppressed by improving the light extraction efficiency.

On the other hand, in the conventional technique in which the wire is substantially parallel to the laser beam in a top view, there is a problem that a shadow of the wire is generated.

(Reflective surface)
Hereinafter, the reflection surface 116 that reflects the laser beam 114 will be described.

The reflective surface 116 is a surface on which the second recess 1202 is formed, and is one side surface facing the right light emitting end surface 100r of the semiconductor laser 100 that emits the laser light 114. The reflecting surface 116 is perpendicular to the upper surface of the lead frame 104 and is plane symmetric with respect to a surface passing through the central axis of the resonator of the semiconductor laser 100.

The reflection surface 116 is composed of an assembly of a plurality of inclined surfaces inclined upward with respect to the upper surface of the lead frame 104. Due to the inclination of each inclined surface, the laser beam 114 emitted in the horizontal direction with respect to the upper surface of the lead frame 104 is reflected in the peripheral direction of the optical axis 118 centering on the direction of the optical axis 118. Moreover, since the reflecting surface 116 is the surface of the resin part 106 containing a light-scattering body, it reflects and reflects the laser beam 114. Due to the shape of the reflecting surface 116 and the scattering reflection on the reflecting surface 116, the spot diameter of the laser beam 114 is appropriately widened. Therefore, the light density of the laser beam 114, particularly the light density around the optical axis, is lower after reflection than before reflection. Become.

In the present embodiment, the inclined surfaces that reflect the laser beam 114 are divided into the second lower inclined surface 1161 from the lower side, the middle inclined surface 1162 above the lower inclined surface 1161, and the upper (upper) of the intermediate inclined surface 1162. To the upper inclined surface 1163. Of these three lower inclined surfaces 1161, middle inclined surfaces 1162, and upper inclined surfaces 1163, the smallest inclined angle with respect to the upper surface of the lead frame 104 is the lower inclined surface 1161, and the inclined angle with respect to the upper surface of the lead frame 104 is The largest is the upper inclined surface 1163.

Further, the reflecting surface 116 has a shape obtained by dividing the locus of the outer peripheral surface of the rotating body rotated around the predetermined axis (rotating axis) by the side surface of the first recess 1201.

Also, no light scatterer exists in the region (recessed portion 120) between the light emitting end face (right light emitting end face 100r) of the semiconductor laser 100 and the reflecting surface 116. For this reason, the laser beam 114 reaches the reflecting surface 116 while maintaining the alignment characteristics when emitted, and can be scattered and reflected upward while controlling the subsequent light distribution in a predictable manner.

(Laser light and eye-safe)
Hereinafter, the laser beam 114 and the eye-safeization of the laser beam 114 will be described.

When the laser beam 114 is emitted from the right light emitting end surface 100r of the semiconductor laser 100 substantially parallel to the upper surface of the lead frame 104, the laser beam 114 is emitted so as to spread at a certain angle from the spot diameter in units of micrometers. For this reason, the laser beam 114 is highly coherent, but spreads away from the right light emitting end surface 100r, so that the light density of the laser beam 114 decreases. For example, the spread angle of the laser beam 114 emitted from the semiconductor laser 100 which is an infrared semiconductor laser is about 20 ° in the direction perpendicular to the active layer and about 10 ° in the direction parallel to the active layer.

Thus, since the laser beam 114 travels while spreading, the spot diameter of the laser beam 114 spreads on the reflecting surface 116 away from the light emitting end surface, and the light density of the laser beam 114 is reduced to some extent. Therefore, the laser beam 114 is already made eye-safe to some extent before being scattered and reflected by the reflecting surface 116.

Further, since the laser beam 114 that has already been made eye-safe to some extent is scattered and reflected by the reflecting surface 116, the laser beam 114 is sufficiently made eye-safe. Since the laser light 114 that is sufficiently eye-safe in this way is emitted from the opening 124 that opens on the upper surface of the package 108, the light emitted from the eye-safe light source 1 is sufficiently eye-safe.

(Luminescence efficiency)
Below, the luminous efficiency of the eye-safe light source 1, which is the amount of light emitted from the eye-safe light source 1 with respect to the power consumed by the eye-safe light source 1, will be described.

The inside of the recess 120 is a cavity, and there is no light scatterer that scatters the laser beam 114. For this reason, the laser beam 114 reaches the reflecting surface 116 without being scattered. Therefore, the scattered light is not absorbed by the submount 102. For this reason, the eye safe light source 1 is excellent in luminous efficiency.

The inside of the recess 120 is a cavity, and the semiconductor laser 100 is covered with air. Since the semiconductor laser 100 is an infrared semiconductor laser, the light emitting end face is optimized and designed to maximize the efficiency of extracting light from the atmosphere (air), as is generally the case. Therefore, since the light can be extracted from the semiconductor laser 100 with maximum efficiency, the eye-safe light source 1 is excellent in luminous efficiency.

Also, there is no light scatterer inside the recess 120, and the laser light 114 does not pass through the light scattering layer including the light scatterer. For this reason, since light absorption by a light-scattering body does not occur, the eye safe light source 1 is excellent in luminous efficiency.

Further, the wire 110 is substantially perpendicular to the direction in which the laser beam 114 is emitted when viewed from above (viewed from a direction perpendicular to the lead frame 104). For this reason, the wire 110 does not block the optical path of the laser beam 114, and the shadow of the wire 110 does not occur in the virtual light source in which the laser beam 114 is made eye-safe. For this reason, the eye safe light source 1 is excellent in luminous efficiency. Furthermore, since the wire 110 extends inside the recess 120 where there is no light scatterer, the wire 110 does not absorb the scattered light. For this reason, the eye safe light source 1 is excellent in luminous efficiency.

The semiconductor laser 100 is mounted on the submount 102 so that the right light emitting end surface 100r protrudes from the submount 102 when viewed from above. For this reason, the laser beam 114 emitted so as to spread from the right light emitting end surface 100r reaches the reflecting surface 116 without being blocked by the submount 102. Further, the semiconductor laser 100 is lifted from the upper surface of the lead frame 104 by sandwiching the submount 102 between the semiconductor laser 100 and the lead frame 104. For this reason, the laser beam 114 can reach the reflecting surface 116 directly without being reflected by the upper surface of the lead frame 104 and without being blocked by the lead frame 104. Therefore, since the shadow of the submount 102 does not occur in the virtual light source in which the laser beam 114 is made eye-safe, and no stray light is generated by reflection on the lead frame 104, the eye-safe light source 1 is excellent in luminous efficiency.

The resin portion 106 having the reflective surface 116 is a white resin including a light scatterer often used for LED light sources. For this reason, the light reflectivity of the reflective surface 116 is high and the light absorption rate is low. Therefore, the eye-safe light source 1 is excellent in luminous efficiency.

(Light distribution characteristics and polarization characteristics)
Below, the polarization characteristic and light distribution characteristic in the eye safe light source 1 are demonstrated.

The laser beam 114 is scattered and reflected by the reflecting surface 116, but is not scattered before reaching the reflecting surface 116. For this reason, the intensity distribution of the light density of the laser beam 114 scattered and reflected by the reflecting surface 116 is determined by shaping the light distribution characteristics depending on the shape of the reflecting surface 116 and averaging by appropriate scattering on the reflecting surface 116. For this reason, the reflection surface 116 lowers the strong intensity peak on the optical axis (center of the spot) of the laser beam 114, and averages the intensity of the light density between the periphery and the center of the spot, while distributing the light distribution characteristics. Can be arranged. Further, the laser beam 114 is sufficiently eye-safe without passing through a light scattering layer including a light scatterer that scatters the laser beam. For this reason, in the eye-safe light source 1, the light distribution characteristics of the laser light 114 can be adjusted while making the laser light 114 eye-safe, and the polarization characteristics of the laser light 114 can be maintained at least partially.

On the other hand, in the conventional techniques such as Patent Documents 2 to 4, the laser light is made eye-safe by passing through a light scattering layer including a light scatterer that scatters the laser light. For this reason, the laser light loses its light distribution characteristics and polarization characteristics due to multiple scattering while passing through the light scattering layer.

Note that the polarization characteristics of the laser light 114 emitted from the eye-safe light source 1 may be adjusted so that the laser light 114 passes through the light scattering layer. For example, the opening 124 may be covered with a cover, and the type or concentration of the light scatterer included in the cover or the thickness of the cover may be adjusted. In this way, the polarization ratio of the laser beam 114 transmitted through the cover and emitted from the eye-safe light source 1 can be adjusted in the range of about 2 to 100. Here, the polarization ratio is the ratio of the intensity of light having the main polarization plane of the light source to the intensity of light having a polarization plane other than the main polarization plane of the light source.

Further, in the eye-safe light source 1, the light distribution characteristics can be adjusted depending on the shape of the reflecting surface 116, so that it is not necessary to provide a lens for adjusting the light distribution characteristics. For this reason, the eye-safe light source 1 is suitable for thinning. In addition, you may provide a lens suitably as needed. For example, in order to use the eye-safe light source 1 optically coupled with an optical fiber, it is desirable to install a lens. The lens may be an external lens or may be integrated with a cover that covers the opening 124.

In addition, the eye-safe laser beam 114 at least partially maintains the polarization characteristics when emitted from the semiconductor laser 100. For this reason, the eye-safe light source 1 is suitable for applications that utilize polarization characteristics. For example, the eye-safe light source 1 may be provided in an electronic device for biometric authentication. A light source with a high polarization ratio is particularly suitable as a light source for vein authentication.

(Effects of reflecting surface)
2A and 2B show the reflection of the laser light by the reflecting surface in the eye-safe light source 1, where FIG. 2A shows the reflection by the middle inclined surface 1162, FIG. 2B shows the reflection by the upper inclined surface 1163, and FIG. It is sectional drawing which showed each reflection by the inclined surface. FIG. 3 is a cross-sectional view showing the spread of the laser light reflected by the intermediate inclined surface 1162, the upper inclined surface 1163, and the lower inclined surface 1161. FIG. 4 is a cross-sectional view showing reflection of laser light by the reflecting surface 117A of the comparative example with respect to the reflecting surface 116. As shown in FIG. FIG. 5 is a cross-sectional view showing the reflection of laser light by the reflection surface 117B of another comparative example with respect to the reflection surface 116. As shown in FIG.

The laser beam 114 emitted from the semiconductor laser 100 is reflected by the middle inclined surface 1162 of the reflecting surface 116 as shown in FIG. Further, the laser beam 114 emitted from the semiconductor laser 100 is reflected by the upper inclined surface 1163 of the reflecting surface 116 at a position farther from the semiconductor laser 100 than the middle inclined surface 1162, as shown in FIG. The Further, the laser beam 114 emitted from the semiconductor laser 100 is reflected by the lower inclined surface 1161 of the reflecting surface 116 at a position closer to the semiconductor laser 100 than the intermediate inclined surface 1162, as shown in FIG. The

Thereby, as shown in FIG. 3, the laser beam 114 emitted from the semiconductor laser 100 is reflected by the lower inclined surface 1161, the intermediate inclined surface 1162, and the upper inclined surface 1163 at different angles, respectively. Therefore, the laser beam 114 can be diverged at an appropriate angle. Further, the degree of divergence of the laser beam 114 can be easily adjusted by the number of inclined surfaces of the reflecting surface 116 and the inclination angle of each inclined surface.

On the other hand, in the light source (Comparative Example 1) shown in FIG. 4, when the laser beam 114 emitted from the semiconductor laser 100 is reflected by the reflecting surface 117A formed in a plane, it diverges over a wide range. In addition, for example, when a scattering reflection surface such as a resin is used as the reflection surface 117A, light may be scattered and a sufficient light flux may not be obtained near the optical axis.

On the other hand, in the light source shown in FIG. 5 (Comparative Example 2), when the laser beam 114 emitted from the semiconductor laser 100 is reflected by the reflecting surface 117B formed by a parabolic surface, the light is concentrated in the optical axis direction. This may cause problems with eye-safety.

As described above, the eye-safe light source 1 of the present embodiment can diverge the laser beam 114 at an appropriate angle as compared with the light sources of Comparative Examples 1 and 2.

Here, the light intensity distribution after reflection for the eye-safe light source 1 and the light sources of Comparative Examples 1 and 2 will be described. FIG. 6 is a graph showing the light distribution characteristics of the model light source used to explain the effect of the reflecting surface 116. FIG. 7A is a graph showing the light intensity distributions of the light reflected from the reflection surface 116 of the light from the model light source and the reflection light from the reflection surfaces 117A and 117B of Comparative Examples 1 and 2, respectively. 7 (b) is a graph showing an enlarged main part of FIG. 7 (a). FIG. 8 shows the light intensity distribution of the reflected light from the middle inclined surface 1162, the reflected light from the upper inclined surface 1163, the reflected light from the lower inclined surface 1161, the combined light of these reflected lights, and the reflected light from the reflecting surface of Comparative Example 1. It is a graph which shows.

As shown in FIG. 6, the light intensity distribution of the light emitted from the model light source used as the semiconductor laser 100 is a Gaussian light having a full width at half maximum of 24 degrees. The light intensity of the light reflected by the reflecting

surfaces

116, 117A, and 117B has a distribution as shown in FIGS. 7A and 7B. From this light intensity distribution, the reflected light from the reflecting surface 116 is moderately converged in the range of −10 ° to + 10 °, whereas the reflected light from the reflecting surface 117A is dispersed in a wide range and reflected by the reflecting surface 117B. It can be seen that the light converges in a narrow range.

As shown in FIG. 8, the reflected light from the reflecting surface 116 of the present embodiment differs from the reflected light from the reflecting surface 117A of Comparative Example 1 in the lower inclined surface 1161, the intermediate inclined surface 1162, and the upper It is obtained from each of the inclined surfaces 1163, and it can be seen that they are converged to an appropriate range by combining them.

So far, in order to facilitate discussion, a two-dimensional virtual case has been described as an example. Hereinafter, a three-dimensional actual case will be described as an example.

FIG. 9A is a perspective view schematically showing the emission of light from the semiconductor laser 100 as a model light source mounted on the submount 102. FIG. 9B is a perspective view schematically showing the radiation of reflected light from the semiconductor laser 100 mounted on the package 108 of the eye-safe light source 1. FIG. 10A is a graph showing typical light distribution characteristics of the laser light shown in FIG. FIG. 10B is a graph showing typical light distribution characteristics of the reflected light shown in FIG. FIG. 10C is a graph showing typical light distribution characteristics obtained when the reflected light shown in FIG. 9B is further passed through the light scattering layer. FIG. 10D is a graph showing a typical light distribution characteristic of reflected light by a reflecting surface (parabolic reflector) made of a paraboloid as a comparative example.

In an actual laser element, the vertical opening angle (θ⊥) and the horizontal opening angle (θ //) of the laser light emitted from the light emitting end face of the laser element are different, and generally θ⊥> θ // As shown in FIG. 9A, the laser beam 114 simply emitted from the semiconductor laser 100 has a vertical opening angle θ⊥ and a horizontal opening angle θ //. The light distribution characteristic in this case has a certain extent as shown in FIG.

On the other hand, as shown in FIG. 9B, the laser beam 114 reflected by the reflecting surface 116 has a vertical opening angle θ′⊥ and a horizontal opening angle θ ′ //. The light distribution characteristics in this case are such that the vertical opening angle θ′⊥ and the horizontal opening angle θ ′ // are appropriate as shown in FIG. Therefore, a moderately narrow light distribution can be obtained. Further, the light distribution characteristic of the reflected light can be adjusted by appropriately changing the number and angle of the inclined surfaces of the reflecting surface 116, the material of the reflecting surface 116, and the like.

In order to use laser light in a living space, it is necessary to use the laser light once as a distributed light source in order to ensure safety for the human retina and the like. A typical method of using laser light as a distributed light source is, for example, a method of using a laser light passing through a light scattering layer containing a filler.

The vertical opening angle θ⊥ and the horizontal opening angle θ // of the laser light that has passed through the light scattering layer are wider than before the passage. In consideration of this change, it is necessary to make the laser light having a light distribution characteristic narrower than the final light distribution characteristic incident on the light scattering layer. For example, by mounting the model light source shown in FIG. 9A as the semiconductor laser 100 on the package 108 shown in FIG. 1, it is possible to narrow the light distribution characteristics.

Next, the procedure for obtaining the required light distribution characteristics will be described.

The values of the vertical opening angle θ⊥ and the horizontal opening angle θ // of the laser beam shown in FIG. 10 (a) are 24 ° and 12 °, respectively. Here, as the light distribution characteristics of the finally required eye-safe distributed light source, as shown in FIG. 10C, the values of the vertical opening angle θ ″ ⊥ and the horizontal opening angle θ ″ // are as follows. Consider the case of both about 24 °.

When the laser light shown in FIG. 10A is directly incident on the light scattering layer and the light scattering layer is adjusted so that the horizontal opening angle θ // = 12 ° becomes the horizontal opening angle θ ″ // = 24 °, Even if the vertical opening angle θ⊥ = 24 ° with the light source, the value of the vertical opening angle θ ″ ⊥ obtained after passing through the scattering layer exceeds a value sufficiently larger than 24 °, for example, 30 ° or 40 °. .

In order to avoid such inconvenience, the light having the radiation characteristic shown in FIG. 10A once emitted from the semiconductor laser is reflected by the reflecting surface 116 of the package 108 shown in FIG. It is preferable to pass light having a light distribution characteristic narrowed and narrowed as shown in FIG.

The light distribution characteristic of the narrowed light shown in FIG. 9B is shown in FIG. 10B as an example, and the vertical opening angle θ′⊥ and the horizontal opening angle θ ′ // are 14 respectively. °, 9 °. In this way, after taking into account the expansion of the opening angle in the light scattering layer, the once focused light is allowed to pass through the light scattering layer, and the vertical opening angle θ ″ ⊥ and the horizontal opening angle θ ″ // are targeted. It is possible to adjust the angle more accurately by adjusting to the angle (24 ° here).

Here, as a comparative example, for example, a parabola-shaped reflector is used, and the light distribution characteristic of the laser light is extremely reduced on the axis ((d) of FIG. 10) and shown in (c) of FIG. A description will be given of obtaining light having a light distribution characteristic close to the light distribution characteristic. FIG. 11 is a graph showing light distribution characteristics including spike-like protrusions obtained when the reflected light from the parabolic reflector is further passed through the light scattering layer.

Such light is allowed to pass through the light diffusion layer, and has a light distribution characteristic with a sufficiently wide opening angle such that ± 60 °, that is, the vertical opening angle θ ″ ⊥ and the horizontal opening angle θ ″ // are both 120 °. It is relatively easy to obtain dispersed light. In order to obtain such dispersed light, it can be obtained by sufficiently increasing the filler concentration in the light diffusion layer and sufficiently scattering the laser light.

On the other hand, for example, ± 15 °, in other words, in order to obtain light in a narrow angle region where the vertical opening angle θ ″ ⊥ and the horizontal opening angle θ ″ // are both less than 30 °, It is necessary to lower the filler concentration in the light diffusion layer as compared with the case.

When light concentrated in the center of the optical axis as shown in FIG. 10D is passed through the light scattering layer under such conditions, as shown in FIG. Light with high intensity remains, and light with a light distribution surrounding the periphery with dispersed light is obtained. With such light distribution, it cannot be said that safety for eyes, that is, eye-safety is sufficiently ensured.

As described above, when laser light is passed through the light scattering layer in order to obtain the desired vertical opening angle θ⊥ and horizontal opening angle θ //, spike-like strong light remains in the optical axis direction. In order to avoid the inconvenience seen in FIG. 11, the light is not concentrated on the center of the optical axis as shown in FIG. The light collected while expanding the light may be employed. This light is light whose axial luminous intensity is lowered as compared with the light distribution characteristic shown in FIG. 10D, and has, for example, the light distribution characteristic shown in FIG.

By using such light, the spike-like protrusions seen in FIG. 11 are substantially eliminated. Thereby, it is possible to realize an appropriately safe eye-safe light source having a smooth light distribution characteristic as shown in FIG. The degree of light collection indicating light distribution is often indicated by a vertical opening angle θ⊥ and a horizontal opening angle θ //, and both are 24 ° in FIG. The value of the light source used for iris authentication is approximately 20 ° to 40 °. From this, it can be said that the light condensed moderately as shown in (c) of FIG. 10 is suitable as a light source for iris authentication.

(Application examples)
In order to realize an eye-safe light source having one light emitting point like the eye-safe light source 1 of the present embodiment, for example, it is conceivable to use a semiconductor laser having an asymmetric emission ratio of 5 to 95 on the left and right. This also applies to the eye-safe light source 4 of the fourth embodiment described later.

(Modification 1)
Hereinafter, Modification 1 of Embodiment 1 in which a cover 128a is provided in the opening 124 in the eye-safe light source 1 according to the modification of Embodiment 1 will be described with reference to FIG.

FIG. 12 is a cross-sectional view for explaining eye-safety in a modification in which the cover 128a that scatters the laser beam 114 is provided in the eye-safe light source 1 shown in FIG. FIG. 12 corresponds to the right portion of FIG. 1B and shows the spread of the laser beam 114 and the optical axis 134. The range of the spread of the laser beam 114 shown in FIG. 12 is a range until the intensity of the light density reaches 1 / e of the peak value (e is the base of natural logarithm).

The cover 128 a is a cover provided so that foreign matter does not enter the recess 120. The cover 128a is formed of a resin including a light scatterer that scatters the laser light 114. In addition, since a breathing hole (not shown) is provided in the cover 128a, gas can enter and leave the recess 120 through the breathing hole. The cover 128a is formed of a resin containing a light scatterer. For this reason, in the modified example in which the cover 128a is provided, the spot diameter of the laser beam 114 is enlarged as shown in FIG.

As shown in FIG. 12, the optical axis 134 is the optical axis of the laser beam 114. The spot diameter R ₀ is the spot diameter of the laser beam 114 on the right light emitting end face 100r. The spot diameter R ₁ is the spot diameter of the laser beam 114 viewed from the direction of the optical axis 134 when the laser beam 114 hits the reflecting surface 116. Further, the spot diameter _{R 2} is, when the laser beam 114 is incident to the cover 128a, a spot diameter of the laser beam 114. Further, the spot diameter _{R 3} is after the laser beam 114 is passed through the cover 128a, a spot diameter of the laser beam 114.

The optical path length l ₁ is the optical path length of the laser light 114 from the right light emitting end surface 100r to the reflecting surface 116 along the optical axis 134 of the laser light 114, and the optical path length l ₂ is the optical axis of the laser light 114. 134 is the optical path length of the laser beam 114 from the reflecting surface 116 to the cover 128 a along the line 134.

The laser beam 114 is emitted from the right emission end face 100r of the semiconductor laser 100 so as to spread at a certain angle from the spot diameter _{R0 in} units of micrometers. For this reason, the spot diameter of the laser beam 114 increases while the laser beam 114 travels parallel to the upper surface of the lead frame 104. The laser beam 114 spreads to the spot diameter R ₁ when it reaches the reflecting surface 116 after traveling by the optical path length l ₁ . Accordingly, as in the case without the cover 128a, the longer the distance (optical path length l ₁ ) between the right light emitting end surface 100r and the reflecting surface 116 of the semiconductor laser 100, the more the laser beam 114 becomes eye-safe due to the spread of the spot diameter. Is done.

The laser beam 114 that has reached the reflecting surface 116 is scattered and reflected by the reflecting surface 116. Due to the scattering reflection, the light density inside the spot of the laser beam 114 is averaged, and the laser beam 114 is further made eye-safe.

The scattered and reflected laser beam 114 travels straight from the reflecting surface 116 to the cover 128a. Then, the optical path length _{l 2} proceeds laser beam 114, when the laser beam 114 reaches the cover 128a, the laser beam 114 is spread to the spot diameter _{R 2.} Therefore, as the distance (optical path length l ₂ ) between the reflecting surface 116 and the cover 128a increases, the laser beam 114 is further made eye-safe due to the spread of the spot diameter.

The laser beam 114 incident on the cover 128a is refracted by the difference in refractive index between the resin forming the cover 128a and the gas (air) filling the inside of the recess 120. Further, the resin forming the cover 128 a includes a light scatterer that scatters the laser beam 114. Thus, refraction and scattering and the spot diameter of the laser beam 114, while passing through the cover 128a, extends from the spot diameter R ₂ of the time of incidence to the spot diameter R ₃ at exit. Further, the light density inside the spot of the laser beam 114 is further averaged by scattering. In this case, the polarization characteristics of the laser beam 114 when emitted from the semiconductor laser 100 can be partially maintained by adjusting the type and concentration of the light scatterer contained in the resin, the thickness of the cover 128a, and the like. . Thereby, the polarization characteristic of the eye-safe light emitted from the eye-safe light source 1 can be adjusted. For example, the polarization ratio can be adjusted in the range of 2 to 100.

As a material used for the cover 128a, for example, a resin typified by an epoxy resin, an acrylic resin, a silicone resin, or the like may be used, and not only the resin but also glass may be used. As the light scatterer included in the cover 128a, silica (SiO ₂ ), titanium oxide (TiO ₂ ), zirconia (ZrO ₂ ), and the like are common, but are not limited thereto.

If the cover 128a is not provided, a virtual light source for eye-safe the laser beam 114 becomes the reflective surface 116, the spot diameter of the virtual light source is a spot diameter R ₁ on the reflecting surface 116. In contrast, in this modification the cover 128a is provided, a virtual light source for eye-safe the laser beam 114 becomes the cover 128a, the spot diameter of the virtual light source is a spot diameter R ₃ of the cover 128a. Therefore, in this modification, the spot diameter of the laser beam 114 is expanded by the optical path length l _{2 as} compared with the case where the cover 128a is not provided. Further, in this modification, the spot diameter of the laser beam 114 is enlarged by refraction at the boundary surface of the cover 128a and scattering by the cover 128a, and the light density of the laser beam 114 is averaged by scattering by the cover 128a.

Thus, in the modified example in which the cover 128a that scatters the laser light 114 is provided with respect to the eye-safe light source 1 according to the first embodiment, the light emitted from the eye-safe light source 1 is further sufficiently eye-safe. .

(Modification 2)
Hereinafter, Modification 3 of Embodiment 1 in which a lens 142 is provided in the opening 124 in the eye-safe light source 1 according to Embodiment 1 will be described with reference to FIG.

In order to use the eye-safe light source 1 optically coupled with an optical fiber, it is desirable to install a lens. In such an application, for the purpose of further adjusting the light distribution characteristic, the opening 124 may be covered with a cover with a lens as shown in FIG. 13B, or the light distribution characteristic is adjusted with an external lens. May be.

FIGS. 13A and 13B are a top view and a cross-sectional view showing a schematic configuration of an eye-safe light source 1A according to a modification in which the cover 142b having a lens 142 that collimates the laser light 114 is provided in the eye-safe light source 1 shown in FIG. .

As shown in FIG. 13, the cover 142b is a cover provided so that foreign matter does not enter the recess 120, and is formed of a resin that does not contain a light scatterer. In addition, since a breathing hole (not shown) is provided in the cover 142b, gas can enter and leave the recess 120 through the breathing hole. The cover 142b is integrally formed so as to include a lens 142 for the laser beam 114 emitted from the right light emitting end surface 100r.

The lens 142 is formed to collimate the laser beam 114 emitted from the right light emitting end surface 100r. The lens 142 may be an aspheric lens or a spherical lens.

[Embodiment 2]
The second embodiment of the present invention will be described below with reference to FIGS. For convenience of explanation, members having the same functions as those described in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

FIG. 14 is a diagram showing a schematic configuration around the semiconductor laser 200 of the eye-safe light source 2 according to the second embodiment of the present invention. FIG. 14A is a top view of the resin portion 406 seen through. FIG. 14B is a cross-sectional view taken along the DD line in FIG. FIG. 14C is a cross-sectional view taken along the line EE of FIG. FIG. 14D is a cross-sectional view taken along the line FF in FIG. FIG. 14E schematically shows the light emission state in the cross-sectional structure shown in FIG.

As shown in FIG. 14, the eye-safe light source 2 includes a semiconductor laser 200 that emits laser light 214, a submount 102 on which the semiconductor laser 200 is mounted, a package 208 having a lead frame 104 and a resin portion 206, and a wire 110. Is provided. A mark 112 is provided so that the direction of the anode and the cathode can be seen.

The eye-safe light source 1 according to the first embodiment and the eye-safe light source 2 according to the second embodiment are different in the following two points.

One point is that in the eye-safe light source 1 according to the first embodiment, the semiconductor laser 100 emits the laser beam 114 only from the light emitting end surface (right light emitting end surface 100r) on the right side, whereas in the eye-safe light source 2 according to the second embodiment. The laser light 214 is emitted from the left and right light emitting end faces (the left light emitting end face 200l and the right light emitting end face 200r).

Another point is that a different recess 220 is provided with respect to the recess 120 in the eye-safe light source 1 according to the first embodiment.

(Concave)
Below, the recessed part 220 with which the resin part 206 is provided is demonstrated.

The concave portion 220 includes a first concave portion 2201 having the same shape as the first concave portion 1201 and a second concave portion 1202, similar to the concave portion 120 configured by combining the first concave portion 1201 and the second concave portion 1202 in the first embodiment. And the second concave portion 2202 having the same shape as that of the second concave portion 2202. In addition, the recess 220 has a third recess 2203 formed on the side surface facing the side surface on which the second recess 2202 is formed among the four side surfaces of the first recess 2201.

The second recess 2202 and the third recess 2203 are disposed so as to face the light emitting end faces (the left light emitting end face 200l and the right light emitting end face 200r) on both the left and right sides of the semiconductor laser 200. The recess 220 according to the second embodiment is a plane (symmetric plane) that passes through the center of the semiconductor laser 200 and is perpendicular to the upper surface of the lead frame 104 (reference surface of the package 208) and the direction in which the laser beam 214 is emitted from the semiconductor laser 200. ). In contrast, the recess 120 according to the first embodiment is a plane (not shown) passing through the center of the semiconductor laser 100 that is perpendicular to the upper surface of the lead frame 104 and the direction in which the laser beam 114 is emitted from the semiconductor laser 100. Not symmetric.

That is, the eye-safe light source 2 according to the second embodiment is different from the eye-safe light source 1 according to the first embodiment in that the semiconductor laser 200 that emits the laser light 214 from both the left and right sides is used. Is different.

As described above, the concave portion 220 included in the resin portion 206 is formed by combining the first concave portion 2201 having a substantially inverted quadrangular frustum shape with the second concave portion 2202 and the third concave portion 2203 having a substantially multi-stage inverted truncated cone shape. 3D shape.

(Reflective surface)
The reflection surface 216 is an inner wall of the resin portion 206 that forms the second recess 2202, and the reflection surface 217 is an inner wall of the resin portion 206 that forms the third recess 2203. The reflecting surfaces 216 and 217 are opposed to the left and right light emitting end surfaces (left light emitting end surface 200l and right light emitting end surface 200r) of the semiconductor laser 200 that emits the laser light 214, respectively. The reflecting surfaces 216 and 217 pass through the center of the semiconductor laser 100 that is perpendicular to the top surface of the lead frame 104 and parallel to the direction in which the semiconductor laser 100 emits the laser beam 114, in addition to being plane-symmetric with respect to the plane described above. It is plane symmetric with respect to the plane (symmetric plane). Further, the reflecting surface 216 has a diameter that increases upward with respect to the upper surface of the lead frame 104, and has a plurality of inclined surfaces like the reflecting surface 116 of the first embodiment.

Further, the reflecting

surfaces

216 and 217 have a shape obtained by dividing the locus of the outer peripheral surface of the rotating body rotated around the predetermined center axis (rotating axis) by the side surface of the first recess 2201. The central axis is plane symmetric with respect to the plane.

(Wire)
The wire 110 may not cast the shadow of the wire 110 on the virtual light source. For this reason, it is desirable that the wire 110 be arranged in a direction orthogonal to the direction in which the laser beam 214 is emitted from the semiconductor laser 100.

(Effects of reflecting surface)
The effect by the

reflective surfaces

216 and 217 will be described.

FIG. 15A is a cross-sectional view showing the light emission state of the eye-safe light source 2. FIG. 15B is a side view of the eye-safe light source 2. FIG. 15C is a side view of the eye-safe light source 2 in a light emitting state. FIG. 16A is a perspective view schematically showing light emission from a semiconductor laser 200 as a model light source mounted on the submount 102. FIG. 16B is a perspective view schematically showing the emission of reflected light from the semiconductor laser 200 mounted on the package 208. FIG. 16C is a schematic diagram showing a state where the reflected light shown in FIG. 16B has passed through the light scattering layer.

As shown in FIG. 15A, in the eye-safe light source 2 according to the second embodiment, the reflecting

surfaces

216 and 217 are made of the laser light 214 as a semiconductor in the same manner as the reflecting surface 116 of the eye-safe light source 1 according to the first embodiment. Scattered and reflected in the direction of the optical axis 218 (symmetric axis) of the laser 200.

In the second embodiment, a direction perpendicular to the upper surface of the lead frame 104 is used as the optical axis 218. Not limited to this, it is also possible to newly adopt another optical axis of the eye-safe light source in the inclined direction with respect to the optical axis 218 shown here by changing the inclination angle of the reflecting

surfaces

216 and 217. is there.

Further, as shown in FIG. 15B, the reflecting surface 216 is formed so that the central axis of the multi-stage inverted truncated cone is perpendicular to the bottom surface (reference surface) of the package 208. As a result, as shown in FIG. 15C, the reflected light from the first recess 216 is emitted in a direction centered on the central axis.

In the first embodiment, the case where light is emitted from one end face of the semiconductor laser 100 as illustrated in FIG. 9 has been described as an example. On the other hand, in the present embodiment, the package 208 is configured to be suitable when the laser beam 214 is emitted from both end faces of the semiconductor laser 200 as shown in FIG. Yes. Hereinafter, the description will be focused on differences from the first embodiment shown in FIG. 1, FIG. 9, and FIG.

The laser beam 214 emitted from the semiconductor laser 200 shown in FIG. 16A has a vertical opening angle θ⊥ and a horizontal opening angle θ //. On the other hand, the reflected light obtained when the semiconductor laser 200 shown in FIG. 16A is mounted on the package 208 has a vertical opening angle θ′⊥ and a horizontal opening angle θ ′ //.

When the total light output of the combined radiation at the left and right end faces of the semiconductor laser 200 is the same as the total light output of the single-sided semiconductor laser 100 shown in FIG. 9A, it is shown in FIG. Thus, when the reflected light passes through the light diffusion layer 215, the light density per unit area is halved. Therefore, in such a case, it can be said that safety and eye-safety are high. This is because the virtual light source size is doubled, and it can be said that the light output distributed per one end surface of the semiconductor laser is halved.

The structure as described above that radiates light symmetrically from the left and right end faces is particularly necessary when using high-power light. Although the

semiconductor lasers

100 and 200 each have one or two light emitting end faces, the light distribution characteristics are the same, and the shapes of the reflecting

surfaces

116 and 216 are the same. The positional relationship between the

surfaces

116 and 216 is the same. In addition, the

semiconductor lasers

100 and 200 have the same light distribution characteristics measured at a long distance as long as the configuration of the light diffusion layer is the same for both the package 108 (see FIG. 1) and the package 208 in the first embodiment.

For this reason, the discussion regarding the far-field pattern (FFP: far field pattern) in the package 108 using FIG. 10 and FIG. This description is omitted to avoid repetition.

(Application examples)
In the eye-safe light source 2 of the present embodiment, a semiconductor laser that emits light asymmetrically on the left and right light emitting end faces may be used instead of the semiconductor laser 200. Such a semiconductor laser can be easily obtained, for example, by changing the reflectance of the end face coat on the left and right. In this way, the left and right light emission can be changed to 40:60, 30:70, 20:80, 10:90, for example. This also applies to Embodiments 3 and 5 described later.

(Modification 1)
Hereinafter, a modification of the second embodiment in which the lens 232 is provided in the opening 224 in the eye-safe light source 2 according to the second embodiment will be described with reference to FIG.

In order to use the eye-safe light source 2 optically coupled with an optical fiber, it is desirable to install a lens. In such an application, for the purpose of further adjusting the light distribution characteristic, the opening 224 may be covered with a cover with a lens as shown in FIG. 17, or the light distribution characteristic may be adjusted with an external lens.

17 is a top view and a cross-sectional view showing a schematic configuration of an eye-safe light source 2A according to a modification example in which the cover 232a having a lens 232 for condensing or collimating the laser beam 214 is provided in the eye-safe light source 2 shown in FIG. FIG.

As shown in FIG. 17, the cover 232a is a cover provided so that foreign matter does not enter the recess 220, and is formed of a resin that does not contain a light scatterer. In addition, since a breathing hole (not shown) is provided in the cover 232a, gas can enter and leave the recess 220 through the breathing hole. The cover 232a is integrally formed to include a lens 232 for the laser light 214 emitted from the left light emitting end surface 200l and the right light emitting end surface 200r.

The lens 232 is formed to condense or collimate the laser light 214 emitted from the left light emitting end surface 200l and the right light emitting end surface 200r. The lens 232 may be an aspherical lens or a spherical lens.

(Modification 2)
Hereinafter, Modification 2 of Embodiment 1 in which a cover 128b is provided in the opening 224 in the eye-safe light source 2 according to Embodiment 2 will be described with reference to FIG.

18 is a top view and a cross-sectional view showing a schematic configuration of an eye-safe light source 1B according to a modification in which the cover 242a having a lens 242 for condensing or collimating the laser beam 214 is provided in the eye-safe light source 2 shown in FIG. FIG.

As shown in FIG. 18, the cover 242a is a cover provided so that foreign matter does not enter the recess 220, and is formed of a resin that does not contain a light scatterer. In addition, since a breathing hole (not shown) is provided in the cover 242a, gas can enter and leave the recess 220 through the breathing hole. The cover 242a is integrally formed to include a lens 242 for the laser light 214 emitted from the left light emitting end surface 100l and the right light emitting end surface 200r.

The lens 242 is formed to condense or collimate the laser light 214 emitted from the left light emitting end surface 100l and the right light emitting end surface 100r. The lens 242 may be an aspherical lens or a spherical lens.

In the modified example 2 in which the cover 242a having the lens 242 is provided, the light emitted from the eye-safe light source 2B has a more uniform light distribution characteristic than in the case where the cover 242a is not provided. For this reason, the eye-safe light source 2B according to the modified example 2 is suitable for an application that optically couples with an optical fiber.

The lens 242 may be an external lens that is not integral with the cover 242a. When the lens 242 is an external lens, it is easy to adjust the light distribution characteristics of the light emitted from the eye-safe light source 2B.

[Embodiment 3]
Embodiment 3 of the present invention will be described below with reference to FIGS. For convenience of explanation, members having the same functions as those described in the first and second embodiments are denoted by the same reference numerals and description thereof is omitted.

FIG. 19 is a diagram showing a schematic configuration around the semiconductor laser 200 of the eye-safe light source 3 according to Embodiment 3 of the present invention. FIG. 19A is a top view of the resin portion 306 seen through without the cover 228. FIG. 19B is a cross-sectional view taken along the line GG in FIG. FIG. 19C is a cross-sectional view taken along the line HH in FIG. FIG. 19D is a cross-sectional view taken along the line II of FIG. FIG. 19E is a cross-sectional view taken along line JJ in FIG. FIG. 19F is a cross-sectional view taken along the line KK in FIG.

As shown in FIG. 19, the eye-safe light source 3 includes a semiconductor laser 200 that emits laser light 214, a submount 102 on which the semiconductor laser 200 is mounted, a package 308 having a lead frame 104 and a resin portion 306, a wire 110, and And a cover 228 having a breathing hole 230. A mark 112 is provided so that the direction of the anode and the cathode can be seen.

(Concave)
Below, the recessed part 320 with which the resin part 306 is provided is demonstrated.

The concave portion 320 has a first concave portion 3201 having the same shape as the first concave portion 2201 according to the second embodiment. The recess 320 has a second recess 3202 and a third recess 3203 instead of the second recess 2202 and the third recess 2203 according to the second embodiment.

Similar to the second recess 2202 and the third recess 2203 according to the second embodiment, the second recess 3202 and the third recess 3203 are opposed to the left and right light emitting end faces (the left light emitting end face 200l and the right light emitting end face 200r) of the semiconductor laser 200. Are arranged to be. The recess 320 is formed so as to be 180 ° rotationally symmetric with respect to the optical axis 218.

(Reflective surface)
The reflective surface 316 is an inner wall of the resin portion 306 that forms the second concave portion 3202, and the reflective surface 317 is an inner wall of the resin portion 306 that forms the third concave portion 3203. The reflecting surfaces 316 and 317 respectively oppose the left and right light emitting end surfaces (the left light emitting end surface 200l and the right light emitting end surface 200r) of the semiconductor laser 200 that emits the laser light 214. The reflecting surfaces 316 and 317 are 180 ° rotationally symmetric with respect to the optical axis 218. In addition, the reflecting

surfaces

316 and 317 have an upward diameter with respect to the upper surface of the lead frame 104, and have a plurality of inclined surfaces, like the reflecting surface 216 of the second embodiment.

Further, the reflecting

surfaces

316 and 317 have the shape of the locus of the outer peripheral surface of the rotating body rotated by the rotating body rotating around a predetermined center axis (rotating axis). The central axis is also rotationally symmetric with respect to the optical axis 218 by 180 °. Further, the central axis is inclined in directions X1 and X2 that are opposite to each other with respect to the optical axis 218. In this respect, the eye-safe light source 2 according to the second embodiment is different from the eye-safe light source 3 according to the third embodiment.

(Effects of reflecting surface)
The effect by the

reflective surfaces

316 and 317 will be described.

20 (a) is a cross-sectional view showing a light emission state of the eye-safe light source 3. FIG. FIG. 20B is a side view of the eye-safe light source 3. FIG. 20C is a side view of the eye-safe light source 3 in a light emitting state. FIG. 21A is a graph showing light distribution characteristics when the angle of inclination of the central axis of the reflecting surface shown in FIG. 20B is 3 °. FIG. 21B is a graph showing the light distribution characteristic when the inclination angle of the central axis of the reflecting surface shown in FIG. 20B is 5 °.

As shown in FIG. 20A, in the eye-safe light source 3 according to the third embodiment, the reflecting

surfaces

316 and 317 are the same as the reflecting surface 216 of the eye-safe light source 2 according to the second embodiment. The light is scattered and reflected in the direction of the optical axis 218 of the laser 200.

Further, the central axes of the reflecting

surfaces

316 and 317 are inclined in different directions as described above. The inclination of the central axis of the reflecting

surfaces

316 and 317 will be described with reference to FIGS.

20B, in the package 306, the central axes of the reflecting

surfaces

316 and 317 are inclined at an inclination angle α (± α) in directions opposite to each other with respect to the optical axis 218. On the other hand, as shown in FIG. 16C, in the package 208 of the eye-safe light source 2 according to the second embodiment, the central axes of the reflecting

surfaces

216 and 217 are not inclined with respect to the optical axis 218.

When the angle formed by the central axes of the reflecting

surfaces

316 and 317 is 2α, the light intensity measured in the direction perpendicular to the upper surface of the lead frame 104 is compared with the package 208 of the eye-safe light source 2 shown in FIG. In the case of Embodiment 3 shown in FIG. For example, if the value of 2α is set to an angle of 4 ° or more and the value of α is set to an angle of 2 ° or more, the light emitted from both ends of the semiconductor laser 200 is reflected on the reflecting

surfaces

316 and 317 at the same time. In many cases, it is possible to avoid the state of being incident on the pupil.

In the eye-safe light source 1 according to the first embodiment, the laser beam 114 emitted from the semiconductor laser 100 exhibits the light distribution characteristic of FIG. In the eye-safe light source 2, the central axes of the two opposing reflecting

surfaces

216 and 217 in the package 208 are parallel (α = 0 °). The light reflected by the reflection surfaces 216 and 217 shows the light distribution characteristics shown in FIG.

On the other hand, in the eye-safe light source 3 according to the present embodiment, the laser light 214 emitted from the semiconductor laser 200 can be expressed as a combination of the light distribution characteristics of the light emitted from both end faces, as in the eye-safe light source 1. The light distribution characteristic of (a) is shown. Further, the light reflected by the reflecting

surfaces

316 and 317 shows the light distribution characteristics of (a) and (b) of FIG. In the eye-safe light source 3, as described above, the angle formed by the central axes of the reflecting

surfaces

316 and 317 is 2α. Therefore, as shown in FIGS. 21A and 21B, the light distribution characteristic of the reflected light is The left light emitting end face 200l (one-dot chain line) and the right light emitting end face 200r (two-dot chain line) are different. Here, the FWHM (full width at half maximum) value indicated by the horizontal opening angle θ // is expanded by tilting the central axes of the reflecting

surfaces

216 and 217 in the direction of the horizontal opening angle θ //.

In the eye-safe light source 2 of Embodiment 2, the value of the horizontal opening angle θ // shown in (b) of FIG. 10 is 9 °. On the other hand, in the light distribution characteristic shown in FIG. 21A in which the central axes of the reflecting

surfaces

316 and 317 are inclined by α = ± 3 ° (2α = 6 °), the value of the horizontal opening angle θ // is 13 °. It is. Further, in the light distribution characteristic shown in FIG. 21B in which the central axes of the reflecting

surfaces

316 and 317 are inclined by α = ± 5 ° (2α = 10 °), the value of the horizontal opening angle θ // is further expanded to 19 °. It becomes. If the light intensity in the optical axis direction (0 ° direction in FIG. 21) of the package 306 is 100 in the light distribution characteristic shown in FIG. 10B, the light intensity is 75 in the light distribution characteristic shown in FIG. In the light distribution characteristic shown in FIG. Even when compared with the peak intensity, the light distribution characteristic shown in FIG. 21B is about 50 (slightly over 50) with respect to the light distribution characteristic shown in FIG.

Thus, by increasing the value of α, the value of the horizontal opening angle θ // is increased without changing the total luminous flux, and the optical axis direction of the package 306 (the 0 ° direction in FIG. 10B) is increased. The light intensity can be reduced.

The laser beam 214 is reflected by the reflecting

surfaces

316 and 317 and then passes through the light diffusion layer. Thereby, the vertical opening angle θ⊥ and the horizontal opening angle θ // of the finally obtained light are substantially the same (see (c) of FIG. 10). As light used for this purpose, light having a light distribution characteristic shown in FIG. This is due to the following reason. By tilting the central axes of the two reflecting

surfaces

316 and 317, the value of the horizontal opening angle θ // before entering the light scattering layer approaches the value of the vertical opening angle θ⊥. This facilitates making the vertical opening angle θ⊥ and the horizontal opening angle θ // substantially the same after passing through the light scattering layer. Thus, the ability to adjust the value of the horizontal opening angle θ // before passing through the light scattering layer is very useful in practice.

Here, the reason why the value of α is set to 2 ° or more is because “Japan Industrial Standards JIS C6802 Condition 3” which is a safety standard regarding a dispersed light source is taken into consideration. Here, “amount of light incident on a φ7 mm aperture placed at a position 10 cm away from the light source” is used as part of the criteria for determining the safety of the dispersed light source. Therefore, when the amount of light detected by an opening of φ7 mm placed at a position 10 cm away from the light source is measured everywhere, it is safer to make the maximum value obtained as small as possible. At this time, it is desired to realize such a situation without reducing the total luminous flux.

The opening angle 2θ when the “opening of φ7 mm placed at a position 10 cm away” is viewed from the light source corresponds to about 4 °. In order to reduce the light intensity entering this region, the opening angle 2α between the central axes of the two reflecting

surfaces

316 and 317 shown in FIGS. 20 and 21 (a) and (b) should be 2α> 2θ. Is desirable. With this setting, the laser light 214 on the left light emitting end surface 200l indicated by the one-dot chain line in FIG. 21A and the laser light 214 on the right light emitting end surface 200r indicated by the two-dot chain line in FIG. Thus, the center of the peak of the light intensity is not directed to the φ7 mm region at the same time. Moreover, it is reasonable from the viewpoint of ensuring the safety of the eyes and retina to suppress as much as possible the maximum amount of light that is simultaneously incident on the above region. The central axes of the reflecting

surfaces

316, 317 typically correspond to the maximum peak of reflected light obtained from each reflecting

surface

316, 317. For this reason, when the central axes of the reflecting

surfaces

316 and 317 are 2α> 2θ = 4 °, two maximum peaks are prevented from entering the range defined by 2θ = 4 ° at the same time, and eye-safety is improved. Is possible. In other words, since the incident light is always limited to one of the reflected lights from the reflecting

surfaces

316 and 317, the safety against the laser light 214 can be improved. For this purpose, light having the light distribution characteristic shown in FIG. 21B is most preferable.

Subsequently, the light intensity when light having the above light distribution characteristics is projected will be described. FIG. 22A is a diagram showing a schematic mapping of light intensity when light having the light distribution characteristics shown in FIG. 21A is projected. FIG. 22B is a diagram showing a schematic mapping of the light intensity when the light having the light distribution characteristic shown in FIG. 21B is projected. FIG. 22C is a diagram showing a schematic mapping of light intensity when light having the light distribution characteristic shown in FIG. 10B is projected. FIG. 23 shows a case where light having a light distribution characteristic shown in FIG. 10D obtained by using a parabolic reflecting surface (parabolic reflector) is projected as a comparative example for the mapping shown in FIG. It is a mapping figure of light intensity. (A) to (c) of FIG. 22 schematically show the light intensity when light having the above-mentioned light distribution characteristics is projected on a 10 cm square surface 30 cm ahead from the light source.

As shown in FIG. 23, the light intensity of the projection light of the light obtained on the reflecting surface of the comparative example is narrowed down, so that only the central portion is brightened. On the other hand, the light intensity of the projection light obtained by the eye-safe light source 2 (Embodiment 2) shown in (c) of FIG. Further, as shown in FIG. 22A, the eye-safe light source 3 (α = 3 °) uniformly irradiates a wider range of the light intensity of the projected light. As shown in FIG. 22B, the eye-safe light source 3 (α = 5 °) uniformly irradiates the widest range of the light intensity of the projected light.

Such light that can uniformly irradiate a moderately wide range is suitable for use in iris authentication, face authentication, and the like. It is desirable that the light having the light distribution characteristics shown in FIGS. 22A and 22B is further passed through the light scattering layer and used for the authentication. The passage of the light scattering layer not only improves eye-safety and widens the uniform light irradiation area, but also reduces speckle noise and interference fringes, which are characteristic of laser beams. ,It is valid. Thus, as an example of the light obtained by the light having the light distribution characteristics shown in FIGS. 22A and 22B passing through the light scattering layer, the light distribution characteristics shown in FIG. The light which has is mentioned.

The central axes of the two reflecting

surfaces

316 and 317 are inclined in directions opposite to each other with respect to the rotation around the through-axis passing through the laser resonator (not shown) of the semiconductor laser 200 in the longitudinal direction of the semiconductor laser 200. You may do it. By adopting such a configuration, it becomes possible to irradiate the laser beam 214 uniformly over a wide range with good symmetry.
(Modification 1)
In the above-described third embodiment, the package 308 having a rotational symmetry of 180 ° with respect to an axis perpendicular to the surface of the lead frame 104 disposed at the center of the package 308 has been described as an example. In this example, the inclination angle of the central axis of the reflecting

surfaces

316 and 317 is ± α. However, the present embodiment is not limited to such a special example. For example, the inclination angle of the central axis of the reflection surface 316 is + α inclination, and the inclination angle of the central axis of the reflection surface 317 is −β ( However, it may be α ≠ β). In this case, it is desirable that α + β> 2θ = 4 °.

(Modification 2)
The inclination angle of the central axis passing through the resonators of the reflecting

surfaces

316 and 317 is not limited to the direction perpendicular to the central axis of the semiconductor laser 200 as in the third embodiment and the first modification. It is assumed that the central axes of the reflecting

surfaces

316 and 317 are inclined in an arbitrary direction and an arbitrary angle depending on the purpose. However, from the viewpoint of eye-safety, if the angle formed by the central axes of the reflecting

surfaces

316 and 317 is 2γ, it is desirable that 2γ> 2θ = 4 °.

[Embodiment 4]
The following will describe another embodiment of the present invention with reference to FIGS. For convenience of explanation, members having the same functions as those described in the first to third embodiments are denoted by the same reference numerals and description thereof is omitted.

FIG. 24 is a diagram showing a schematic configuration around the semiconductor laser 100 of the eye-safe light source 4 according to Embodiment 4 of the present invention. FIG. 24A is a top view of the resin portion 406 seen through, except for the cover 228. FIG. 24B is a cross-sectional view taken along line LL in FIG. FIG. 24C is a cross-sectional view taken along the line MM in FIG. FIG. 24D is a cross-sectional view taken along the line NN in FIG.

As shown in FIG. 24, the eye-safe light source 4 includes a semiconductor laser 100 that emits laser light 114, a submount 102 on which the semiconductor laser 100 is mounted, a package 408 having a lead frame 104 and a resin portion 406, a wire 110, and And a cover 228 having a breathing hole 230. A mark 112 is provided so that the direction of the anode and the cathode can be seen.

(Concave)
Below, the recessed part 420 with which the resin part 406 is provided is demonstrated.

The recess 420 has a first recess 4201 having the same shape as the first recess 1201 according to the first embodiment. The recess 420 has a second recess 4202 instead of the second recess 1202 according to the first embodiment.

The second recess 4202 is disposed so as to face the right light emitting end surface (right light emitting end surface 200r) of the semiconductor laser 100, like the second recess 1202 according to the first embodiment.

(Reflective surface)
The reflective surface 416 is an inner wall of the resin portion 406 that forms the second recess 4202. The reflective surface 416 faces the light emitting end surface (right light emitting end surface 100r) on the right side of the semiconductor laser 100 that emits the laser light 114. The reflective surface 416 is 180 ° rotationally symmetric with respect to the optical axis 118. In addition, the reflecting surface 416 has an upward diameter with respect to the upper surface of the lead frame 104, and has a plurality of inclined surfaces like the reflecting surface 116 of the first embodiment.

Also, the reflecting surface 416 has a shape of a locus on the outer peripheral surface of the rotating body rotated by a rotating body rotating around a predetermined center axis (rotating axis). The central axis is inclined with respect to the optical axis 118. In this respect, the eye-safe light source 4 according to the fourth embodiment is different from the eye-safe light source 1 according to the first embodiment.

(Effects of reflecting surface)
The effect by the reflective surface 416 will be described.

FIG. 25A is a cross-sectional view showing a light emission state of the eye-safe light source 4. FIG. 25B is a side view of the eye-safe light source 4. FIG. 25C is a side view of the eye-safe light source 1 of the first embodiment in a light emitting state.

As shown in FIG. 25A, in the eye-safe light source 4 according to the fourth embodiment, the reflection surface 416 emits laser light 114 from the semiconductor laser 100 in the same manner as the reflection surface 116 of the eye-safe light source 1 according to the first embodiment. Scattered and reflected in the direction of the optical axis 118.

25 (c), in the eye-safe light source 1 according to the first embodiment, the central axis of the reflecting surface 116 is not inclined with respect to the optical axis 118. On the other hand, as shown in FIG. 25B, the central axis of the reflecting surface 416 is inclined with respect to the optical axis 118 as described above. With this configuration, it is possible to easily tilt the optical axis of the reflected light without using a lens. This makes it easier to reduce the thickness of the light source compared to a configuration using lenses.

[Embodiment 5]
The fifth embodiment of the present invention will be described below with reference to FIGS. 26 and 27. For convenience of explanation, members having the same functions as those described in the first to fourth embodiments are denoted by the same reference numerals and description thereof is omitted.

FIG. 26 is a diagram showing a schematic configuration around the semiconductor laser 200 of the eye-safe light source 5 according to the fifth embodiment of the present invention. FIG. 26A is a top view of the resin portion 506 seen through without the cover 228. FIG. 26B is a cross-sectional view taken along the line OO in FIG. FIG. 26 (c) is a cross-sectional view taken along the line PP in FIG. 26 (a). FIG. 26D is a cross-sectional view taken along the line QQ in FIG. FIG. 26E is a cross-sectional view taken along the line RR in FIG. FIG. 26F is a cross-sectional view taken along the line SS of FIG.

As shown in FIG. 26, the eye-safe light source 5 includes a semiconductor laser 200 that emits laser light 214, a submount 102 on which the semiconductor laser 200 is placed, a package 508 having a lead frame 104 and a resin portion 506, a wire 110, and And a cover 228 having a breathing hole 230. A mark 112 is provided so that the direction of the anode and the cathode can be seen.

(Concave)
Below, the recessed part 520 with which the resin part 506 is provided is demonstrated.

The recess 520 has a first recess 5201 having the same shape as the first recess 2201 according to the second embodiment. The recess 520 includes a second recess 5202 and a third recess 5203 instead of the second recess 2202 and the third recess 2203 according to the second embodiment.

Similarly to the second recess 2202 and the third recess 2203 according to the second embodiment, the second recess 5202 and the third recess 5203 are opposed to the left and right light emitting end surfaces (the left light emitting end surface 200l and the right light emitting end surface 200r) of the semiconductor laser 200. Are arranged to be. The recess 520 is formed so as to be 180 ° rotationally symmetric with respect to the optical axis 218.

(Reflective surface)
The reflective surface 516 is an inner wall of the resin portion 506 that forms the second concave portion 5202, and the reflective surface 517 is an inner wall of the resin portion 306 that forms the third concave portion 3203. The reflecting surfaces 516 and 517 are opposed to the left and right light emitting end surfaces (left light emitting end surface 200l and right light emitting end surface 200r) of the semiconductor laser 200 that emits the laser light 214, respectively. The reflection surfaces 516 and 517 are 180 ° rotationally symmetric with respect to the optical axis 218. Further, the reflecting

surfaces

516 and 517 are inclined surfaces whose diameter is increased upward with respect to the upper surface of the lead frame 104.

Further, the reflecting

surfaces

516 and 517 are formed in a parabolic shape (parabolic shape), and have a shape of a locus in which a parabola rotates around a predetermined central axis (rotating axis). In this respect, the eye-safe light source 5 according to the fifth embodiment is different from the eye-safe light source 3 according to the third embodiment. The central axis is asymmetric with respect to the plane, and the central axis is inclined in different directions with respect to the optical axis 218 in common with the eye-safe light source 3 according to the third embodiment.

(Effects of reflecting surface)
The effect by the

reflective surfaces

516 and 517 will be described.

FIG. 27A is a cross-sectional view showing a light emission state of the eye-safe light source 5. FIG. 27B is a side view of the eye-safe light source 5. FIG. 27C is a side view of the eye-safe light source 5 in a light emitting state in which the central axis of the reflecting surface is not inclined with respect to the optical axis.

As shown in FIG. 27A, in the eye-safe light source 5 according to the fifth embodiment, the reflecting

surfaces

516 and 517 emit the laser beam 214 in the same manner as the reflecting

surfaces

316 and 317 of the eye-safe light source 3 according to the third embodiment. The semiconductor laser 200 is scattered and reflected substantially in the direction of the optical axis 218.

Further, the central axes of the reflection surfaces 516 and 517 are inclined in different directions as described above. By tilting the central axes of the reflecting

surfaces

516 and 517 with respect to each other, the entire optical axis of the eye-safe light source 5, that is, the light density in the direction perpendicular to the lead frame 104 can be reduced. As described above, the eye-safe light source 5 according to the fifth embodiment also has improved eye-safety due to the same discussion as that of the third embodiment.

As shown in FIG. 27B, in the eye-safe light source 5, the central axes of the reflecting

surfaces

516 and 517 are inclined to each other, so that the two optical axes intersect with each other, and the on-axis luminous intensity of the package 508 as a whole is obtained. Decreases. If the angle formed by the central axes of the reflecting

surfaces

516 and 517 is represented by 2γ, it is also desirable in this embodiment that 2γ> 2θ = 4 ° or more. Further, the inclination angle and direction of the central axis of the reflecting

surfaces

516 and 517 may be symmetric according to the purpose, or may be an arbitrary direction and an arbitrary angle. This also holds similarly to the third embodiment.

In the eye-safe light source shown in FIG. 27C as a comparative example, the central axes of the two reflecting surfaces are not inclined with respect to the optical axis, so that the reflected light from the two reflecting surfaces proceeds in the same direction.

The central axes of the two reflecting

surfaces

516 and 517 are opposite to each other with respect to the rotation around the through-axis passing through the laser resonator (not shown) of the semiconductor laser 200 in the longitudinal direction of the semiconductor laser 200. It may be inclined. By adopting such a configuration, it becomes possible to irradiate uniformly over a wide range with good symmetry.

[Embodiment 6]
The following describes Embodiment 6 of the present invention with reference to FIGS. 28 and 29. FIG. For convenience of explanation, members having the same functions as those described in the first to fifth embodiments are denoted by the same reference numerals and description thereof is omitted.

<Configuration 1>
FIG. 28 is a diagram showing a schematic configuration around the semiconductor laser 100 of the eye-safe light source 6 according to Embodiment 6 of the present invention. FIG. 28A is a top view of the resin portion 606 seen through, except for the cover 628. FIG. 28B is a cross-sectional view taken along the line TT in FIG. FIG. 28C is a cross-sectional view taken along the line U-U in FIG.

As shown in FIGS. 28A to 28C, the eye-safe light source 6 includes a semiconductor laser 100 that emits a laser beam 114, a submount 102 on which the semiconductor laser 100 is mounted, a lead frame 104, and a resin portion 606. And a cover 628 (light scattering layer) having a breathing hole 630. A mark 112 is provided so that the direction of the anode and the cathode can be seen.

Further, the recess 620 of the resin portion 606 is formed by the first recess 6201 and the second recess 6202. The reflective surface 616 that forms the second recess 6202 is formed by applying metal plating to the surface of the resin portion 606. Due to the metal plating, the reflecting surface 616 reflects the laser beam 114 without scattering. Note that the surface of the resin portion 606 other than the reflective surface 616 may or may not be subjected to metal plating.

When the eye-safe light source 1 according to the first embodiment and the eye-safe light source 6 according to the sixth embodiment are compared, the difference is the following one point.

One point is that in the eye-safe light source 1 according to the first embodiment, the reflective surface 116 remains the surface of the resin portion 106, whereas in the eye-safe light source 6 according to the sixth embodiment, the reflective surface 616 is formed by metal plating. It has been done. That is, unlike the first embodiment, the reflecting surface 616 according to the sixth embodiment can increase the ratio of light reflected without scattering the laser light 114.

(Reflective surface)
Hereinafter, the reflecting surface 616 formed by metal plating will be described.

Since the reflection surface 616 is covered with metal plating, the laser beam 114 parallel to the upper surface of the lead frame 104 is reflected in a direction parallel to the optical axis 118 with almost no scattering. Further, since the inside of the recess 620 is hollow, air exists in the recess 620, but there is no light scatterer that scatters the laser light 114. Accordingly, the laser beam 114 travels without being scattered until it reaches the cover 628 from the light emitting end face (the right light emitting end face 100r). Since the laser beam 114 incident on the cover 628 is not scattered, the polarization characteristic when the laser beam 114 is emitted from the semiconductor laser 100 is maintained. Further, since the light distribution characteristic can be easily predicted only from the shape of the reflecting surface 616, optical design can be easily performed.

The reflection surface 616 is separated from the light emitting end surface (right light emitting end surface 100r) of the semiconductor laser 100, and the laser beam 114 is emitted so as to spread from the light emitting end surface (right light emitting end surface 100r) of the semiconductor laser 100. For this reason, on the reflecting surface 616, the spot diameter of the laser beam 114 is widened, and the light density of the laser beam 114 is reduced. Therefore, the laser beam 114 reflected by the reflecting surface 616 is not scattered but is made eye-safe to some extent.

When the semiconductor laser 100 is an infrared semiconductor laser, the metal used for the reflecting surface 616 is preferably gold or an alloy containing gold as a component. The reason is that, in addition to high reflectivity in the wavelength region exceeding 700 nm or in the infrared region, gold is a very stable substance in a normal environment and is not subject to corrosion, oxidation, or the like. On the other hand, silver and the like have high initial light reflectivity, but are susceptible to corrosion or oxidation. In particular, silver and the like are known to be blackened by sulfurization with respect to sulfur, and a special surface coat is required. For this reason, as a metal used for the surface of the reflective surface 616, gold or an alloy containing gold as a component is desirable.

It is also possible to directly coat the resin portion 606 with electroless plating. However, the present invention is not limited thereto, and the reflective surface 616 may be formed by covering the resin portion 606 with the surface of the reflective structure formed by punching from a metal plate with a metal mold in advance. Compared to the electroless plating of the resin portion 606, the electrolytic plating of the metal structure has less problems such as peeling of the reflecting surface and it is easy to ensure long-term reliability. The reflective surface 616 made of such a metal plate may be integrally formed when the resin portion 606 is formed, or may be attached after the resin portion 606 is formed. In addition to coating the metal surface with gold, a reflective surface 616 may be used that is obtained by alumite-treating the surface of a reflective structure formed of aluminum or an aluminum alloy. Since the reflectivity and corrosion resistance of the alumite-treated plate after the surface mirror treatment are equivalent to the reflectivity and corrosion resistance of gold, respectively, it is suitable for ensuring long-term reliability.

As another method of forming the metal reflecting surface, the reflecting surface may be formed by taking in and molding a film-like metal when the resin portion 606 is molded. Here, the film-like metal is preferably protected by a resin film.

(cover)
Hereinafter, the cover 628 formed of a resin containing a light scatterer will be described.

Since the cover 628 is formed of a resin containing a light scatterer, the cover 628 scatters the transmitted laser beam 114. Due to the scattering, the spot diameter of the laser beam 114 is widened, and the light density of the laser beam 114 is lowered. Therefore, the laser beam 114 transmitted through the cover 628 is sufficiently eye-safe.

On the other hand, the light distribution characteristics and polarization characteristics of the laser light 114 are disturbed by scattering, but the laser light 114 transmitted through the cover 628 maintains a certain degree of light distribution characteristics and polarization characteristics. This is because the laser beam 114 is already made eye-safe to some extent when it enters the cover 628, and therefore the laser beam 114 can be made sufficiently eye-safe by scattering within a range that does not lose the light distribution characteristic and the polarization characteristic. .

For example, the concentration of the light scatterer included in the resin forming the cover 628 and the thickness of the cover 628 are adjusted. Thereby, it is possible to achieve both sufficient eye-safety of the laser beam 114 and sufficient maintenance of the light distribution characteristic or polarization characteristic of the laser beam 114.

(Supplementary information on submount)
In the first to fifth embodiments, the case where the

semiconductor lasers

100 and 200 are mounted on the lead frame 104 via the submount 102 has been disclosed. This is because if a semiconductor laser chip that is directly tall without using a submount is used, the heat dissipation becomes worse, and the stress caused by expansion and contraction of the metal lead frame 104 is directly applied to the active layer of the semiconductor laser chip. This is because a decrease in the optical output of the semiconductor laser chip or a sudden death occurs. By using the submount 102, it is possible to prevent such a decrease in light output and the occurrence of sudden death. As in each of the first to fifth embodiments, the use of a submount is indispensable in a structure in which the light emitting point (light emitting end face) is set apart from the lead frame and the laser beam is efficiently irradiated to the opposing reflecting surface.

In particular, unlike gallium nitride semiconductor lasers that use sapphire semiconductor lasers and gallium nitride (GaN) -based substrates with high thermal conductivity, infrared semiconductor lasers that use gallium arsenide (GaAs) -based substrates have low thermal conductivity. In particular, it is necessary to pay attention to heat dissipation. For this reason, what can be directly mounted on the lead frame is limited to a low-power infrared semiconductor laser or a GaN-based semiconductor laser with high heat dissipation.

Further, instead of the submount, the lead frame 104 corresponding to the semiconductor laser mounting portion may be formed in a protruding shape. In order to form the shape in this way, it is conceivable to use press working or etching when forming the lead frame. In this case, it is desirable to use a metal having a small expansion coefficient, such as iron or an alloy containing iron as a main raw material, so that the expansion and contraction of the metal frame does not adversely affect the reliability of the semiconductor laser. . Furthermore, it is important to join the semiconductor laser chip to the lead frame 104 with a material that reduces the influence of expansion and contraction, such as indium solder. Even when the lead frame portion is processed into a projecting shape, it is necessary that this shape does not block the optical path of the laser beam. In general, forming such a shape on a lead frame takes time and is difficult to obtain accuracy. From this point of view, it is desirable to use the submount 102.

In this configuration, the example in which the reflection surface 616 is made of metal is shown, but instead, the reflection surface may be made of a resin including a light scatterer that scatters laser light. The same applies to Configuration 2 described below.

<Configuration 2>
FIG. 29 is a diagram showing a schematic configuration around the semiconductor laser 200 of another eye-safe light source 7 according to Embodiment 6 of the present invention. FIG. 29A is a top view of the resin portion 706 seen through with the cover 628 removed. FIG. 29B is a cross-sectional view taken along arrow VV in FIG. FIG. 29C is a cross-sectional view taken along the line XX of FIG.

As shown in FIGS. 29A to 29C, the eye-safe light source 7 includes a semiconductor laser 200 that emits a laser beam 214, a submount 102 on which the semiconductor laser 200 is mounted, a lead frame 104, and a resin portion 706. And a cover 628 (light scattering layer) (not shown in FIG. 29) having a breathing hole 630. A mark 112 is provided so that the direction of the anode and the cathode can be seen.

Further, the concave portion 720 of the resin portion 706 is formed by a first concave portion 7201, a second concave portion 7202, and a third concave portion 7203. The reflective surface 716 that forms the second recess 7202 is formed by applying metal plating to the surface of the resin portion 706. The reflective surface 717 that forms the second recess 7203 is also formed in the same manner as the reflective surface 716. Due to the metal plating, the reflecting

surfaces

716 and 717 reflect the laser light 214 almost without scattering. In addition, about the surface of the resin parts 706 other than the reflective surfaces 716,717, metal plating may be given and it is not necessary to give.

When comparing the eye-safe light source 2 according to the second embodiment and the other eye-safe light source 7 according to the sixth embodiment, the difference is the following two points.

One point is that in the eye-safe light source 2 according to the second embodiment, the reflecting

surfaces

216 and 217 remain on the surface of the resin portion 206, whereas in the eye-safe light source 7 according to the sixth embodiment, the reflecting

surfaces

716 and 717 are metal. It is formed by plating. That is, unlike the second embodiment, the reflecting surface 716 according to the sixth embodiment reflects the laser light 214 almost without being scattered.

Another point is that in the eye-safe light source 2 according to the second embodiment (the modification shown in FIG. 18), the cover 232a may be formed of a resin not including a light scatterer, whereas the eye-safe according to the sixth embodiment. In the light source 7, it is desirable that the cover 628 be formed of a resin containing a light scatterer. That is, unlike the second embodiment, it is desirable that the cover 628 scatters the transmitted laser light 214.

The description of the “reflecting surface” described above for the eye-safe light source 6 having the configuration 1 is the same for the eye-safe light source 7 having the configuration 2, and thus the description thereof is omitted here. Further, since the above-described “cover” and “supplement regarding submount” can also be applied to the eye-safe light source 7 of Configuration 2, the description thereof is omitted here.

[Embodiment 7]
The seventh embodiment of the present invention will be described below with reference to FIG. For convenience of explanation, members having the same functions as those described in the first to sixth embodiments are denoted by the same reference numerals and description thereof is omitted.

FIG. 30 is a diagram showing a schematic configuration of the optical sensor 8 according to Embodiment 7 of the present invention.

As shown in FIG. 30, the optical sensor (electronic device) 8 includes an eye-safe light source 11, a light receiving unit 832 that receives reflected light from a living body, and a control unit 834 that controls the eye-safe light source 11 and the light receiving unit 832. .

The eye-safe light source 11 is configured by any one of the eye-safe light sources 1 to 7 according to the first to sixth embodiments.

The light receiving unit 832 may be provided in any one of the packages 108 to 708 similarly to the eye-safe light sources 1 to 7. Further, the light receiving unit 832 may be provided separately from the eye-safe light sources 1 to 7.

The control unit 834 may be a semiconductor element provided in any one of the packages 108 to 708. In other words, the control unit 834 may be a semiconductor element that is bonded to the lead frame 104 and sealed with any one of the resin units 106 to 708. Further, the control unit 834 may be provided separately from the eye-safe light source 11.

The eye-safe light emitted from the eye-safe light source 11 is reflected by the living body, and the light receiving unit 832 receives the reflected light reflected by the living body. And the control part 834 calculates the information of the biological body which reflected eye safe light by comparing the eye safe light radiated | emitted from the eye safe light source 11, and the reflected light received by the light-receiving part 832. An image element may be used as the light receiving unit 832, and image data may be analyzed by the control unit 834 to obtain biological information.

Since the eye-safe light source 11 is a surface mount type light source suitable for thinning, the optical sensor 8 is thin. The types of biological information that can be collected using the eye-safe light source 11 as a light source are diverse, such as irises, veins such as fingers and palms, fingerprints, and palm prints. In order to realize biometric authentication using such biometric information with a portable electronic device, the eye-safe light source 11 is effectively used. The present invention is not limited to these portable electronic devices, and can be used as a light source for ordinary stationary electronic devices such as a cash dispenser (ATM), an electronic lock-type safe, an electronic key for a car or a house.

In addition, since thinning is widely required for electronic devices, the use of the eye-safe light source 11 is not limited to biometric authentication. The eye safe light source 11 may be used for a projector, a projector, a night vision camera light source, a motion sensor light source, a small electronic device, a portable electronic device, and the like. Even a communication device, for example, an electronic device that requires optical coupling with an optical fiber, can effectively use a small, surface-mount type eye-safe light source.

In addition, the eye-safe light source according to each of the embodiments described above is a small projector, a light source for a night vision camera, a light source for a motion sensor, a small projector, and an electronic device for biometric authentication, particularly for biometric authentication using polarization characteristics. It can be used for electronic devices. Furthermore, it can also be used as a light source for communication equipment, for example, electronic equipment that requires optical coupling with an optical fiber. Each eye-safe light source is suitable for surface mounting.

[Summary]
The eye-safe light source according to aspect 1 of the present invention includes a substrate (packages 108 to 708) and

semiconductor lasers

100 and 200 that emit

laser beams

114 and 214 from the light emitting end surfaces (left light emitting end surface 100l and right light emitting end surface 100r). The

semiconductor lasers

100 and 200 are bonded to the substrate so as to emit the

laser beams

114 and 214 in parallel to the reference plane of the substrate, and the substrate reflects the

laser beams

114 and 214. Surface 116, reflecting

surfaces

216, 317, 317, 517, 516, the reflecting surface 116 is provided so as to face the light emitting end surface, and is composed of an assembly of multi-stage inclined surfaces, The inclination angle of the inclined surface is different so as to increase as it approaches the emission end of the

laser beams

114 and 214.

According to the above configuration, the laser light is emitted in a direction parallel to the reference surface of the substrate and reflected by the reflecting surface. For this reason, the optical path length from the light emitting end surface to the reflecting surface can be increased without increasing the thickness of the eye-safe light source. By increasing the optical path length from the light emitting end surface to the reflecting surface, the spot diameter of the laser beam on the reflecting surface can be increased. By widening the spot diameter, the light density of the laser light can be lowered, and the laser light can be made eye-safe. In addition, the reflecting surface is an aggregate composed of multi-step inclined surfaces, and laser light having a desired light distribution opening angle or an opening angle close thereto can be easily obtained.

Further, according to the above configuration, the laser light can be made eye-safe without passing through the light scattering region including the light scatterer or through the light scattering region within a range in which the polarization characteristics can be maintained. it can. Thereby, the light emitted from the eye-safe light source maintains (at least partially) the polarization characteristics of the laser light. For this reason, this eye safe light source is suitable for the use which utilizes a polarization characteristic, for example, is suitable for the optical sensor for biometrics authentication.

Further, according to the above configuration, the laser light can be made eye-safe without passing through the light scattering layer including the light scatterer or through the light scattering layer within a range in which the polarization characteristics can be maintained. it can. Thereby, the light distribution characteristic of the laser light can be adjusted by the multi-stage reflection surface, and the light emitted from the eye-safe light source maintains (at least partially) the light distribution characteristic adjusted by the reflection surface. For this reason, in an eye safe light source, the luminous efficiency of the light radiated | emitted from an eye safe light source can be adjusted with the improvement of luminous efficiency.

The eye-safe light source according to aspect 2 of the present invention is the above-described aspect 1, wherein the light emitting end faces are provided on both sides of the semiconductor laser 200, and the reflecting

surfaces

216, 317, 317, 517, 516, 616, 716, 717 may be provided to face each of the light emitting end faces.

The eye-safe light source according to aspect 3 of the present invention is the above-described aspect 2, wherein the light emitting end faces are optically symmetrical with each other, and the reflecting

surfaces

216, 317, 317, 517, 516, 616, 716, 717 A plane of symmetry that passes through the center of the semiconductor laser and is perpendicular to the direction in which the laser beam is emitted from the end face may be plane symmetric.

The eye-safe light source according to Aspect 4 of the present invention is the eye-safe light source according to any one of Aspects 1 to 3, wherein the reflecting

surfaces

116, 216, 317, 317, 517, 516, 616, 716, 717 are rotating bodies around a central axis. It may be formed so as to form a shape of a part of the trajectory rotated.

The eye-safe light source according to aspect 5 of the present invention is the eye safe light source according to aspect 2, wherein the light emitting end faces are optically symmetrical with each other, and the reflecting

surfaces

217, 317, 517, and 516 emit the laser light from the light emitting end faces. Asymmetric with respect to a plane of symmetry passing through the center of the semiconductor laser perpendicular to the direction of symmetry and symmetric with respect to a symmetry axis that is perpendicular to the reference plane of the substrate and passing through the center of the semiconductor laser. Also good.

The eye-safe light source according to aspect 6 of the present invention is the eye safe light source according to aspect 5 described above, wherein the reflecting

surfaces

217, 317, 517, and 516 rotate around respective central axes inclined in different directions with respect to the reference surface of the substrate. You may form so that the shape of a part of locus | trajectory which the body rotated may be made | formed.

The eye-safe light source according to aspect 7 of the present invention is the eye-safe light source according to aspect 6, wherein the central axes of the two reflecting surfaces rotate about a through-axis that penetrates the laser resonator of the semiconductor laser in the longitudinal direction of the semiconductor laser. On the other hand, they may be inclined in opposite directions.

The eye-safe light source according to aspect 8 of the present invention is the above-described aspect 2, wherein the light emitting end faces are optically symmetrical with each other, and the reflecting

surfaces

217, 317, 517, and 516 are different from the reference surface of the substrate. You may form so that the shape of a part of locus | trajectory which the rotary body rotated centering on each central axis inclined in direction may be made.

According to the configurations of the above aspects 2 to 8, since the reflecting surface is an aggregate composed of multi-step inclined surfaces, the width and the inclination angle of the inclined surface of each step can be adjusted. It becomes easy to bring the orientation characteristics close to ideal. In addition, by tilting the central axis of the reflecting surface with respect to the symmetry axis, it is possible in many cases to avoid the state where light emitted from both ends of the semiconductor laser is reflected on the reflecting surface and simultaneously enters the human pupil.

The eye-safe light source according to the ninth aspect of the present invention includes a substrate (package 508) and a semiconductor laser 200 that emits laser light 214 from a light emitting end face (left light emitting end face 100l, right light emitting end face 100r). The laser beam 214 is bonded to the substrate so as to be emitted in a horizontal direction with respect to the reference surface of the substrate, and the light emitting end surfaces are provided on both sides of the semiconductor laser 200 and are optically connected to each other. The substrate has two reflecting

surfaces

516 and 517 that reflect the laser beam 200, and the reflecting

surfaces

516 and 517 are provided to face the light emitting end surface, respectively. In addition, each of the reflecting

surfaces

516 and 517 is formed so as to have a shape of a part of a parabolic surface of a locus in which a parabola rotates around the central axis. Inclined in different directions with respect to the reference plane of the substrate.

According to the above configuration, the laser light is emitted in a direction parallel to the reference surface of the substrate and reflected by the reflecting surface. For this reason, the optical path length from the light emitting end surface to the reflecting surface can be increased without increasing the thickness of the eye-safe light source. By increasing the optical path length from the light emitting end surface to the reflecting surface, the spot diameter of the laser beam on the reflecting surface can be increased. By widening the spot diameter, the light density of the laser light can be lowered, and the laser light can be made eye-safe. Further, by making the reflecting surface a paraboloid, laser light having a desired light distribution opening angle or laser light having an opening angle close thereto can be easily obtained. In addition, by tilting the central axis of the reflecting surface in different directions with respect to the reference surface of the substrate, the light emitted from both ends of the semiconductor laser is reflected by the reflecting surface and then enters the human pupil at the same time. It can be avoided in many cases.

An eye-safe light source according to aspect 10 of the present invention is the eye safe light source according to aspect 9, wherein the central axis is asymmetric with respect to a symmetry plane that passes through the center of the semiconductor laser 200 and is perpendicular to the direction in which the laser light 200 is emitted from the light emitting end surface. And may be 180 ° rotationally symmetric with respect to an axis of symmetry that is perpendicular to the reference plane of the substrate and passes through the center of the semiconductor laser 200.

The eye-safe light source according to aspect 11 of the present invention is the eye safe light source according to aspect 10, in which the central axes of the two reflecting

surfaces

516 and 517 penetrate the laser resonator of the semiconductor laser 200 in the longitudinal direction of the semiconductor laser 200. You may incline in a mutually reverse rotation direction with respect to the rotation around a penetration axis.

The eye-safe light source according to aspect 12 of the present invention is the eye safe light source according to aspect 11, wherein the substrate includes a metal lead frame 104 and a resin (resin portion 506) that at least partially covers the metal lead frame 104. The semiconductor laser 200 may be bonded to the metal lead frame 104.

The eye-safe light source according to Aspect 13 of the present invention is the semiconductor laser according to any one of Aspects 1 to 12, wherein the light emitting end surface protrudes from the submount when viewed from the direction perpendicular to the substrate. It may be joined to the substrate via the submount.

The eye-safe light source according to the fourteenth aspect of the present invention is the eye-safe light source according to any one of the first to thirteenth aspects, wherein the light emitting end surface and the reflecting

surfaces

216, 317, 317, 517, 516 facing the light emitting end surface The light scatterer which scatters the laser beam 214 may not exist.

In the eye-safe light source according to aspect 15 of the present invention, in any of the above aspects 1 to 14, the reflection surfaces 616, 716, and 717 may be formed of a resin including a light scatterer that scatters the laser light 214. Good.

In the eye-safe light source according to Aspect 16 of the present invention, in any one of Aspects 1 to 14, the reflection surfaces 616, 716, and 717 may be made of metal.

The eye-safe light source according to aspect 17 of the present invention is the laser light 114 reflected by the reflecting

surfaces

116, 216, 317, 317, 517, 516, 616, 716, 717 in any of the above aspects 1 to 16. 214 may pass through a light scattering layer including a light scatterer that scatters the laser light.

In the eye-safe light source according to aspect 18 of the present invention, in any of the above aspects 1 to 17, the

semiconductor lasers

100 and 200 may not be resin-sealed.

In the eye-safe light source according to Aspect 19 of the present invention, in any one of Aspects 1 to 18, the gas covering the

semiconductor lasers

100 and 200 may be able to enter and exit outside.

In the eye-safe light source according to aspect 20 of the present invention, in any of the above aspects 1 to 19, the

semiconductor lasers

100 and 200 may be gas-sealed with an inert gas.

An electronic apparatus (optical sensor 8) according to aspect 21 of the present invention includes the eye-safe light source according to any one of aspects 1 to 20.

According to said structure, an electronic device provided with the eye safe light source which concerns on this invention is realizable.

The electronic device (optical sensor 8) according to Aspect 22 of the present invention is the electronic device according to Aspect 21, and is preferably an electronic device for biometric authentication.

According to the above configuration, an electronic device for biometric authentication provided with the eye-safe light source according to the present invention can be realized.

The electronic apparatus (optical sensor 8) according to aspect 23 of the present invention is the electronic apparatus according to aspect 21 described above, and is preferably a small projector.

According to the above configuration, a small projector equipped with the eye-safe light source according to the present invention can be realized.

The electronic apparatus (optical sensor 8) according to aspect 24 of the present invention is the electronic apparatus according to aspect 21 described above, and is preferably a small projector.

According to the above configuration, a small projector including the eye-safe light source according to the present invention can be realized.

The electronic apparatus (optical sensor 8) according to aspect 25 of the present invention is the electronic apparatus according to aspect 21 described above, and is preferably coupled to an optical fiber.

The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention. Furthermore, a new technical feature can be formed by combining the technical means disclosed in each embodiment.

For example, each of

Embodiments

2, 3, 5, and 6 discloses a structure that is bilaterally symmetric and a structure that is rotationally symmetric. This does not exclude the intentional use of an asymmetry. Further, the optical axis after the laser light is reflected by the reflecting surface is not necessarily in the direction perpendicular to the lead frame. It is possible to easily tilt the optical axis in the desired direction by changing the tilt angle between the left and right reflecting surfaces, or by tilting the central axis of the paraboloid with respect to the perpendicular to the lead frame. It is naturally included in the technical scope of the invention.

1, 1A, 1B, 2-7, 11 Eye-safe light source 8 Optical sensor (electronic equipment)
100, 200 Semiconductor laser 100l Left emission end face (light emission end face)
100r Right emission end face (light emission end face)
102 Submount 104 Lead frame (metal lead frame)

104a Anode part

104c Cathode part

106, 206, 306, 406, 506, 606, 706 Resin part (resin)
108, 208, 308, 408, 508, 608, 708 Package (substrate)
110

Wire

114, 214

Laser beam

116, 216, 316, 416, 516, 616, 716, 717

Reflective surface

118, 218 Optical axis (symmetric axis)
120, 220, 320, 420, 520, 620, 720 Recessed portion 122

Exposed portion

124, 224

Openings

128a, 228b, 628 Cover (light scattering layer)
132, 142 Lens 134

Optical axis

230, 630 Breathing hole 832 Light receiving unit 834 Control unit

Claims

A substrate,
A semiconductor laser that emits laser light from the light emitting end face,
The semiconductor laser is bonded to the substrate so as to emit the laser light in a horizontal direction with respect to a reference surface of the substrate,
The substrate has a reflective surface that reflects the laser light;
The reflection surface is provided so as to face the light emitting end surface, and is composed of an assembly of multi-step inclined surfaces, and the inclination angle of the inclined surface increases as it approaches the emission end of the laser beam. Eye-safe light source characterized by different.
The light emitting end faces are provided on both sides of the semiconductor laser,
The eye-safe light source according to claim 1, wherein the reflecting surface is provided to face each of the light emitting end surfaces.
The light emitting end faces are optically symmetric with respect to each other;
3. The eye-safe light source according to claim 2, wherein the reflection surface is symmetrical with respect to a symmetry plane that passes through a center of the semiconductor laser and is perpendicular to a direction in which the laser light is emitted from the light emitting end surface.
The eye-safe light source according to any one of claims 1 to 3, wherein the reflecting surface is formed so as to form a part of a locus of rotation of the rotating body around a central axis.
The light emitting end faces are optically symmetric with respect to each other;
The reflective surface is
Asymmetric with respect to a symmetry plane that passes through the center of the semiconductor laser and is perpendicular to the direction in which the laser light is emitted from the light emitting end face;
3. The eye-safe light source according to claim 2, wherein the eye-safe light source is symmetric with respect to a symmetry axis that is perpendicular to the reference plane of the substrate and passes through the center of the semiconductor laser.
The reflecting surface is formed so as to form a part of a locus of rotation of a rotating body around respective central axes inclined in different directions with respect to the reference surface of the substrate. The eye-safe light source according to claim 5.
The central axes of the two reflecting surfaces are inclined in directions opposite to each other with respect to rotation about a through-axis passing through the laser resonator of the semiconductor laser in the longitudinal direction of the semiconductor laser. The eye-safe light source according to claim 6.
The light emitting end faces are optically symmetric with respect to each other;
The reflecting surface is formed so as to form a part of a locus of rotation of a rotating body around respective central axes inclined in different directions with respect to the reference surface of the substrate. The eye-safe light source according to claim 2.
A substrate,
A semiconductor laser that emits laser light from the light emitting end face,
The semiconductor laser is bonded to the substrate so as to emit the laser light in a horizontal direction with respect to a reference surface of the substrate,
The light emitting end faces are provided on both sides of the semiconductor laser and are optically symmetric with respect to each other;
The substrate has two reflecting surfaces that reflect the laser light,
Each of the reflecting surfaces is provided so as to face the light emitting end surface, and is formed so as to have a shape of a part of a parabolic surface of a locus in which a parabola rotates around a central axis.
The eye-safe light source characterized in that the respective central axes of the reflecting surfaces are inclined in different directions with respect to the reference surface of the substrate.
The central axis is
Asymmetric with respect to a symmetry plane that passes through the center of the semiconductor laser and is perpendicular to the direction in which the laser light is emitted from the light emitting end face;
10. The eye-safe light source according to claim 9, wherein the eye-safe light source has a rotational symmetry of 180 ° with respect to a symmetry axis that is an axis that passes through a center of the semiconductor laser and is perpendicular to a reference plane of the substrate.
The central axes of the two reflecting surfaces are inclined in directions opposite to each other with respect to the rotation about the through-axis passing through the laser resonator of the semiconductor laser in the longitudinal direction of the semiconductor laser. The eye-safe light source according to claim 10.
The substrate includes a metal lead frame and a resin that at least partially covers the metal lead frame;
The eye-safe light source according to any one of claims 1 to 11, wherein the semiconductor laser is bonded to the metal lead frame.
13. The semiconductor laser is bonded to the substrate via the submount so that the light emitting end face protrudes from the submount when viewed from a direction perpendicular to the substrate. The eye-safe light source according to any one of the above.
The eye-safe according to any one of claims 1 to 13, wherein there is no light scatterer that scatters the laser light between the light emitting end surface and the reflecting surface facing the light emitting end surface. light source.
The eye-safe light source according to any one of claims 1 to 14, wherein the reflecting surface is formed of a resin including a light scatterer that scatters the laser light.
The eye-safe light source according to any one of claims 1 to 14, wherein the reflecting surface is made of metal.
The eye-safe light source according to any one of claims 1 to 16, wherein the laser light reflected by the reflecting surface is transmitted through a light scattering layer including a light scatterer that scatters the laser light.
The eye-safe light source according to any one of claims 1 to 17, wherein the semiconductor laser is not resin-sealed.
The eye-safe light source according to claim 18, wherein the gas covering the semiconductor laser can enter and exit outside.
The eye-safe light source according to claim 18, wherein the semiconductor laser is sealed with an inert gas.
The eye-safe light source according to any one of claims 1 to 20, wherein the laser beam has a wavelength longer than 700 nm.
The eye-safe light source according to any one of claims 1 to 21, wherein the eye-safe light source is a surface-mount type eye-safe light source.
An optical opening parallel to the substrate,
The eye-safe light source according to any one of claims 1 to 22, wherein the laser light is emitted from the opening.
An electronic device comprising the eye-safe light source according to any one of claims 1 to 23.
The electronic device according to claim 24, wherein the electronic device is a biometric authentication electronic device.
The electronic device according to claim 24, wherein the electronic device is a small projector.
The electronic device according to claim 24, wherein the electronic device is a small projector.