JPWO2018168429A1 - Lighting equipment - Google Patents

Abstract

The illumination device (100) includes a semiconductor laser element (1) that emits a plurality of laser lights, an aspheric lens (50) that receives the plurality of laser lights, and converts the incident plurality of laser lights into convergent light. A fluorescent material (90) that emits fluorescent light when the convergent light is irradiated as excitation light, and a reflecting mirror (70) having a first focal point and a second focal point and reflecting the fluorescent light. The phosphor (90) is located in the focal region of the first focal point of the reflecting mirror (70), at a position shifted from the focal point of the aspherical lens (50) in the optical axis direction of the convergent light.

Description

  The present disclosure relates to an illuminating device, and more particularly to an illuminating device that uses fluorescent light emitted from a phosphor by irradiating the phosphor with laser light from a laser light source as illumination light.

  2. Description of the Related Art In recent years, technical development of an illuminating device that irradiates a phosphor with laser light from a semiconductor laser element and uses wavelength-converted fluorescence as illumination light has been actively performed. Conventionally, as such a lighting device, a lighting device disclosed in Patent Document 1 is known. Hereinafter, the light source unit disclosed in Patent Document 1 will be described with reference to FIG. FIG. 18 is a cross-sectional view illustrating a schematic configuration of a conventional lighting device disclosed in Patent Document 1.

  The light source unit 1020 condenses the excitation light emitted from the laser module 1102 by the lens 1110, excites the phosphor 1112, converts it into visible light (for example, white light), and uses the visible light as illumination light. It is used for, for example, a vehicle headlamp.

  As shown in FIG. 18, a light source unit 1020 includes, as a laser module 1102, a laser diode 1104 mounted on a substrate 1106, which oscillates laser light, and a lens 1110 which captures and condenses laser light emitted from the laser diode 1104. It consists of. Further, a part of the housing 1206 is provided with a paraboloidal reflecting mirror 1208 and a transmitting member 1204. Further, as shown in an enlarged view 1030, a reflecting mirror 1114 and a phosphor 1112 are laminated on a part of the transmitting member 1204. Excitation light emitted from the laser module 1102 is guided from the light transmitting portion 1116 provided in a part of the reflecting mirror 1208 to the concave side of the reflecting mirror 1208 to excite the phosphor 1112 to generate white fluorescent light. Further, the phosphor 1112 is positioned at the focal point F of the reflecting mirror 1208, and the generated white fluorescent light is converted into a substantially parallel light beam and emitted to the outside of the housing 1206.

JP 2005-150041 A

However, in the configuration of the conventional light source unit 1020 shown in FIG. 18, when a high-output laser beam is focused on a phosphor in order to produce high-luminance and high-output illumination light, the light density becomes too high. The excited electrons are depleted. For this reason, so-called luminance saturation occurs in which the energy conversion efficiency of the phosphor is saturated. Further, there is a case where the quenching of the temperature of the phosphor occurs as the temperature rises. Further, when the temperature of the phosphor exceeds the heat-resistant temperature, there is a problem that the phosphor itself is burned and deteriorated. Patent Document 1 mentions light distribution pattern control in a white light irradiation region, but does not specifically disclose illuminance uniformity. Further, a reflector is provided on the substrate side of the phosphor, so that the phosphor cannot be directly observed from outside the housing, and the size of the phosphor is larger than the light emitting area of the laser diode, which is generally considered to be 100 μm ² or less. Is set smaller, there is a problem that it is very difficult to mutually align the laser module, the phosphor, and the rotating parabolic reflector.

  The present disclosure is intended to solve such a problem, and an object of the present disclosure is to provide a lighting device capable of irradiating illumination light with high energy efficiency and high illuminance uniformity with a simple configuration.

  In order to solve the above-described problem, one embodiment of an illumination device according to the present disclosure includes a laser light source that emits a plurality of laser lights, the plurality of laser lights being incident, and the converged plurality of laser lights being incident. An optical lens that converts the convergent light into excitation light, and a phosphor that emits fluorescence when irradiated with the convergent light, and a reflecting mirror that has a first focus and a second focus and reflects the fluorescence. The phosphor is located in a focal region of the first focal point of the reflecting mirror and is shifted from a focal point of the optical lens in an optical axis direction of the converged light.

  By arranging the phosphor at a position deviated from the focal point of the optical lens, the light density of the convergent light on the phosphor can be suppressed. For this reason, it is possible to suppress the energy conversion efficiency of the phosphor from being reduced due to luminance saturation. Further, by using a plurality of laser beams, the degree of freedom in adjusting the intensity distribution of the convergent light on the phosphor can be increased. Therefore, by forming an intensity distribution suitable for the shape of the reflecting mirror, the illuminance uniformity of the illumination light emitted from the illumination device can be improved. Further, the above effects can be realized without complicating the configuration of the lighting device.

  Further, in one aspect of the illumination device according to the present disclosure, the projected image of the fluorescent light in the focal region of the second focal point of the reflecting mirror has a first intensity distribution region and the first intensity distribution region. A second intensity distribution region having a small fluorescence intensity, wherein the first intensity distribution region is included in the second intensity distribution region, and a center of the first intensity distribution region and the second intensity distribution region May coincide with the center of the intensity distribution region.

  With this configuration, alignment between the laser light source that emits a plurality of laser beams, the phosphor, and the reflecting mirror can be realized with high accuracy. Further, such alignment can be realized by adjusting the center positions of the first intensity distribution region and the second intensity distribution region. That is, the first intensity distribution region and the second intensity distribution region can be easily confirmed by visual observation or the like, and thus alignment can be easily realized. Further, by realizing high-precision alignment, it is possible to increase the fluorescence collecting efficiency of the reflecting mirror.

  In one aspect of the lighting device according to the present disclosure, the laser light source may be a semiconductor laser element having a plurality of light-emitting regions in one stacked body.

  Thus, the size of the laser light source can be reduced.

  Further, in one aspect of the illumination device according to the present disclosure, the optical lens is an aspheric lens, and has a function of equalizing a light intensity distribution in a direction in which a divergence angle of the plurality of laser lights is large, and The body may be arranged at a position closer to the optical lens than a focal point of the optical lens.

  Thereby, the peak intensity of the convergent light on the surface of the phosphor can be reduced, and the decrease in energy conversion efficiency due to luminance saturation, temperature quenching, and the like can be suppressed. Further, by disposing the phosphor at a position closer to the optical lens than the focal point of the optical lens, a plurality of laser beams can be applied to the phosphor with a uniform intensity distribution formed by overlapping the intensity distributions of the plurality of laser beams. Can be irradiated.

  In one aspect of the illumination device according to the present disclosure, the optical lens has a minute lens region in which a plurality of minute lenses are formed, each of the plurality of minute lenses has a different focus, and the phosphor Is disposed at a position farther from the optical lens than the focal point of each of the plurality of microlenses, and a plurality of components of the plurality of laser beams, which are respectively condensed by the plurality of microlenses, are on a light emitting surface of the phosphor. By overlapping, each light intensity distribution in the direction in which the divergence angle of the plurality of laser beams is large and small in the light emitting surface may be uniform.

  Thereby, the peak intensity of the laser beam on the light emitting surface of the phosphor can be further reduced, and a decrease in energy conversion efficiency due to luminance saturation, temperature quenching, and the like can be further suppressed. Further, by providing the aperture of the reflecting mirror near the focal point of each minute lens, the aperture area can be reduced, so that the fluorescence reflection loss due to the aperture can be reduced and the energy efficiency can be increased.

  Further, in one aspect of the illumination device according to the present disclosure, a shape of at least a part of the plurality of microlenses as viewed in the optical axis direction of the plurality of laser beams may be a square shape or a hexagonal shape.

  Thereby, the gap between the adjacent minute lenses can be reduced to the minimum. Therefore, the area of the gap that does not act as a lens can be minimized, so that a plurality of laser beams can be more efficiently used as excitation light.

  In one aspect of the lighting device according to the present disclosure, the reflecting mirror may have a spheroidal reflecting surface.

  Thereby, the fluorescent light emitted from the phosphor disposed in the focal region of the first focal point can be focused on the second focal point. Also, since the fluorescence reflected by the reflector once intersects at the second focal point, the shadow of the support member or the like that supports the phosphor is more intense than when the fluorescence is emitted as parallel light by the paraboloidal reflector. It is possible to suppress the formation on the fluorescence irradiation surface.

  According to the present disclosure, it is possible to provide a lighting device capable of irradiating illumination light with high energy efficiency and high illuminance uniformity with a simple configuration.

FIG. 1 is a cross-sectional view illustrating a schematic configuration of the lighting device according to the first embodiment. FIG. 2 is a first schematic cross-sectional view showing a path of a laser beam in the lighting device according to the first embodiment. FIG. 3 is a second schematic cross-sectional view showing a fluorescent light path in the lighting device according to the first embodiment. FIG. 4A is a first schematic cross-sectional view illustrating details of a fluorescence path in the vicinity of a first focal point and a second focal point of the reflecting mirror according to the first embodiment. FIG. 4B is a second schematic cross-sectional view illustrating details of the fluorescence path in the vicinity of the first focal point and the second focal point of the reflecting mirror according to Embodiment 1. FIG. 4C is a schematic diagram of the projected image of the fluorescence on the xy plane in the focal region of the second focal point of the reflecting mirror in the illumination device according to Embodiment 1. FIG. 5 is a perspective view illustrating a schematic configuration of the semiconductor laser light emitting device according to the first embodiment and a plurality of laser light emission modes from the semiconductor laser element. FIG. 6 is a schematic diagram of a yz section showing a laser beam path for explaining the operation of the aspheric lens according to the first embodiment. FIG. 7 is a schematic diagram of a zx cross section showing a laser light path for explaining the operation of the aspheric lens according to the first embodiment. FIG. 8 is a distribution diagram showing a two-dimensional distribution on the xy plane of the convergent light intensity at the position where the phosphor according to the first embodiment is arranged. FIG. 9 is a yz cross-sectional view illustrating a schematic configuration of the illumination device according to the second embodiment. FIG. 10A is a plan view illustrating a schematic configuration of the optical lens according to Embodiment 2. FIG. FIG. 10B is a first cross-sectional view illustrating a schematic configuration of the optical lens according to Embodiment 2. FIG. 10C is a second sectional view showing a schematic configuration of the optical lens according to Embodiment 2. FIG. 11 is a schematic diagram of a zx cross section showing a laser beam path for explaining a function of the optical lens according to the second embodiment. FIG. 12A is a schematic diagram of a one-dimensional profile in the x-axis direction at the position of the optical lens with laser light intensity according to Embodiment 2. FIG. 12B is a schematic diagram of a one-dimensional profile in the x-axis direction at the position of the phosphor of the laser light intensity according to Embodiment 2. FIG. 13 is a schematic diagram of a yz section showing a laser beam path for explaining the function of the optical lens according to the second embodiment. FIG. 14A is a schematic diagram of a one-dimensional profile of the position of an optical lens of laser light intensity in the y-axis direction according to Embodiment 2. FIG. 14B is a schematic diagram of a one-dimensional profile in the y-axis direction of the position of the phosphor of the laser light intensity according to Embodiment 2. FIG. 15 is a graph showing the intensity distribution of convergent light in the phosphor of the lighting device according to Embodiment 2. FIG. 16A is a plan view illustrating a schematic configuration of an optical lens according to a modification of the second embodiment. FIG. 16B is a first cross-sectional view illustrating a schematic configuration of an optical lens according to a modification of the second embodiment. FIG. 16C is a second cross-sectional view illustrating a schematic configuration of an optical lens according to a modification of the second embodiment. FIG. 17 is a schematic diagram of a projected image of the fluorescence on the xy plane near the second focal point of the reflecting mirror of the illumination device according to the modification of the second embodiment. FIG. 18 is a cross-sectional view illustrating a schematic configuration of a conventional lighting device.

  Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Each of the embodiments described below shows a specific example of the present disclosure. Therefore, numerical values, shapes, materials, components, arrangement positions of components, connection forms, and the like shown in the following embodiments are examples and do not limit the present disclosure. Therefore, among the components in the following embodiments, components that are not described in the independent claims that indicate the highest concept of the present disclosure are described as arbitrary components.

  In addition, each drawing is a schematic diagram and is not necessarily strictly illustrated. Therefore, the scale and the like do not always match in each drawing. In each of the drawings, substantially the same components are denoted by the same reference numerals, and redundant description will be omitted or simplified.

(Embodiment 1)
[1-1. Configuration of lighting device]
Illumination device 100 according to Embodiment 1 will be described with reference to FIG. FIG. 1 is a cross-sectional view illustrating a schematic configuration of a lighting device 100 according to Embodiment 1. FIG. 1 shows three-dimensional orthogonal coordinate axes of the x-axis, the y-axis, and the z-axis. FIG. 1 shows a vertical cross section of the lighting device 100 parallel to the yz plane.

  As shown in FIG. 1, a lighting device 100 according to the present embodiment includes a semiconductor laser light emitting device 19, a metal base member 20, a heat sink 30, a lens holding member 40, an aspheric lens 50, and a connecting member 60. , A reflecting mirror 70, a supporting member 80, a high reflection substrate 85, and a phosphor 90.

  The semiconductor laser light emitting device 19 is a light emitting device including the semiconductor laser element 1. In the present embodiment, the semiconductor laser light emitting device 19 further includes a submount 2 on which the semiconductor laser element 1 is disposed, a stem 10b supporting the submount 2, a base 10a on which the stem 10b is disposed, and the like.

  The semiconductor laser device 1 is an example of a laser light source that emits a plurality of laser beams, and is, for example, a nitride semiconductor light emitting device including a light emitting layer formed of a nitride semiconductor. In the present embodiment, the semiconductor laser device 1 is a multi-emitter type semiconductor laser device, and has a plurality of light emitting regions in one laminated body. Thereby, a downsized laser light source can be realized.

  The peak wavelength of the laser light emitted from the semiconductor laser device 1 is not particularly limited, but is 390 nm or more and 460 nm or less in the present embodiment. Specifically, the semiconductor laser device 1 is an InGaN-based multi-emitter laser diode device that emits a plurality of blue-violet laser beams having a peak wavelength of 405 nm.

  The metal base member 20 is a member to which the semiconductor laser light emitting device 19 is fixed, and is formed of a high heat radiation metal material having a high thermal conductivity such as aluminum and copper. The semiconductor laser light emitting device 19 is fixed to one end of the metal base member 20. Laser light emitted from the semiconductor laser device 1 travels in a direction opposite to the direction from the semiconductor laser device 1 toward the metal base member 20. In order to enhance the heat radiation of the metal base member 20, a heat sink 30 is provided on the surface of the metal base member 20 opposite to the surface on which the semiconductor laser light emitting device 19 is mounted.

  The heat sink 30 is a member that dissipates heat conducted from the metal base member 20. Although the configuration of the heat sink 30 is not particularly limited, in the present embodiment, the heat sink 30 is formed of a high heat dissipating metal material having a high thermal conductivity, such as aluminum or copper, and has a plurality of air cooling fins.

  The reflecting mirror 70 is a reflector having a reflecting surface 71 on its surface, has a first focal point (primary focal point) and a second focal point (secondary focal point), and reflects the fluorescence emitted from the phosphor 90. I do. An example of such a reflecting mirror 70 is a reflecting mirror having a spheroidal reflecting surface (elliptical reflecting mirror), and the reflecting surface 71 of the reflecting mirror 70 is a spheroidal concave surface. An opening 75 is provided in the reflecting mirror 70. Specifically, the opening 75 is a through hole provided at the top of the long axis of the reflecting mirror 70. Note that the opening 75 need not be a through hole. For example, the opening 75 may be a notch formed in the reflecting mirror 70.

  In addition, the reflecting mirror 70 may be a structure in which a metal thin film serving as the reflecting surface 71 is formed on the surface of a structure having a predetermined shape, or the entire reflecting mirror 70 may be made of metal.

  The metal base member 20 and the reflecting mirror 70 are connected by a connecting member 60. A cylindrical cavity is provided inside the connecting member 60, and the lens holding member 40 is provided inside the hollow. The aspheric lens 50 is held in the lens holding member 40. That is, the connecting member 60 also functions as a lens barrel.

  The aspheric lens 50 is an example of an optical lens that receives a plurality of laser beams emitted from the semiconductor laser device 1 and converts the plurality of incident laser beams into convergent light. The aspheric lens 50 is made of a translucent material such as quartz, for example, and is arranged on the optical paths of a plurality of laser beams of the semiconductor laser device 1. The plurality of laser beams emitted from the semiconductor laser device 1 are collected by the aspheric lens 50. In the present embodiment, the aspheric lens 50 has a function of making the light intensity distribution uniform in the direction in which the divergence angles of the plurality of laser beams are large. In other words, the aspheric lens 50 not only condenses the plurality of laser beams that have entered, but also has a function of beam shaping (for example, shaping into a top hat type irradiation distribution). The function of the aspherical lens 50 will be described later in detail.

  The phosphor 90 is a wavelength conversion element that emits fluorescence when convergent light is irradiated as excitation light. The phosphor 90 is located in a focal region of the first focal point of the reflecting mirror 70 and at a position shifted from the focal point of the aspherical lens 50 in the optical axis direction of the convergent light. Here, the focal region of the first focal point is the first focal point and a region near the first focal point. The focal region of the first focal point is, for example, a region where the distance from the first focal point is 10% or less of the diameter of the reflecting mirror 70. Note that the focal region of the first focal point may be a region where the distance from the first focal point is 5% or less of the diameter of the reflecting mirror 70. Thereby, the fluorescence emitted from the phosphor 90 can be accurately focused on the second focal point. Note that the focus area of the second focus is similarly defined.

  In the present embodiment, the phosphor 90 is formed on the high reflection substrate 85. The phosphor 90 formed on the high-reflection substrate 85 is supported by the support member 80 and is a focal region of the first focal point of the reflecting mirror 70, which is closer to the aspheric lens 50 than the focal point of the aspheric lens 50. Is located in the position. As a result, the defocused convergent light is applied to the light emitting surface 91 of the phosphor 90 from the just-focused position of the aspherical lens 50, so that the light density of the convergent light on the phosphor 90 can be suppressed. Therefore, it is possible to suppress the energy conversion efficiency of the phosphor 90 from being reduced due to luminance saturation. Note that, as described above, the light emitting surface 91 of the phosphor 90 is also an excitation surface on which the convergent light that is the excitation light of the phosphor 90 is irradiated. Further, the optimum installation position of the phosphor 90 will be described later in detail together with the function of the aspheric lens 50.

The fluorescent material constituting the phosphor 90 is, for example, SCA (Sr ₅ (PO ₄ ) ₃ Cl: Eu ²⁺ ) fluorescent material for blue light emission and Ga-YAG (Y ₃ (Al, Ga) ₅ O ₁₂ ) for yellow light emission. : Ce ³⁺ ) is a mixture with a fluorescent material. The blue light emitting SCA is excited by blue-violet laser light having a peak wavelength of 405 nm emitted from the semiconductor laser device 1 to emit blue light. The Ga-YAG for yellow light emission is excited by the blue-violet laser light emitted from the semiconductor laser device 1 to emit yellow light. The combined light of blue light and yellow light appears white to humans. Therefore, by irradiating the phosphor 90 with the laser light emitted from the semiconductor laser element 1, the phosphor 90 emits white light as synthetic light in which blue light and yellow light are mixed. That is, the phosphor 90 produces white fluorescence.

  The support member 80 is a member that supports the phosphor 90. In the present embodiment, the support member 80 has a rod shape with a rectangular cross section, and one end in the longitudinal direction is fixed to a part of the reflecting mirror 70 as shown in FIG. Thereby, the relative position of the phosphor 90 with respect to the reflecting mirror 70 can be fixed. The support member 80 is formed of a material having high thermal conductivity, such as graphite and copper. Further, the support member 80 may be a material having high transparency to visible light in addition to high thermal conductivity, such as GaN, SiC, AlN, or diamond. Thereby, the absorption or reflection of the fluorescent light by the support member 80 can be reduced. Therefore, the fluorescence emission efficiency of the illumination device 100 can be increased. FIG. 1 shows an example in which one end of the support member 80 in the longitudinal direction is fixed to a reflecting mirror. However, a phosphor 90 is provided at the center of the supporting member 80 in the longitudinal direction, and both ends of the supporting member 80 have the reflecting mirror 70. May be fixed. In that case, the heat radiation performance from the phosphor 90 is further improved. Further, the phosphor 90 can be more strongly fixed to the reflecting mirror 70.

[1-2. Operation of lighting device]
Next, the operation of lighting device 100 according to Embodiment 1 will be described with reference to FIGS. Each drawing shows the three-dimensional orthogonal coordinate axes of the x-axis, the y-axis, and the z-axis as in FIG.

  FIG. 2 and FIG. 3 are first and second schematic cross-sectional views showing the paths of laser light and fluorescence in the lighting device 100 according to the first embodiment, respectively. FIGS. 2 and 3 show vertical cross sections of the illumination device 100 parallel to the yz plane and the zx plane, respectively.

  First, the path of the laser light will be described with reference to FIG. As shown in FIG. 2, the blue-violet laser light 111 emitted from the semiconductor laser light emitting device 19 is converted from the divergent light into the convergent light 51 by the aspherical lens 50, and then is transmitted through the opening 75 of the reflecting mirror 70. And the light is emitted to the light emitting surface 91 of the phosphor 90 disposed near the first focal point (focus area) of the reflecting mirror 70. At this time, heat generated by the reactive power of the semiconductor laser device 1 (power obtained by subtracting the optical output from the input power) is dissipated from the heat sink 30. A part of the convergent light 51 applied to the phosphor 90 is absorbed by the phosphor 90 and converted into blue and yellow fluorescent light. Then, white fluorescent light, which is a synthesized light synthesized by mixing the blue fluorescent light and the yellow fluorescent light, is obtained.

  Next, the course of the fluorescence will be described with reference to FIG. The white fluorescent light 110 generated by the phosphor 90 is reflected by the reflecting surface 71 of the reflecting mirror 70, is reflected by the reflecting surface 71, is radiated as convergent light outside the reflecting mirror 70, and is reflected as a spheroidal surface. The light is focused on the second focal point f2 of the surface 71. In the present embodiment, since the reflecting mirror 70 has the spheroidal reflecting surface 71, the fluorescence reflected by the reflecting mirror 70 once intersects at the second focal point as shown in FIG. For this reason, it is possible to suppress the formation of the shadow of the support member 80 or the like that supports the phosphor 90 on the fluorescence irradiation surface as compared with the case where the fluorescence is emitted as parallel light by the paraboloid of reflection mirror.

  Most of the white fluorescent light that reaches the vicinity of the second focal point f2 of the reflecting mirror 70 is emitted from the phosphor 90 excited by the convergent light 51 in the Lambertian light distribution on the reflecting surface 71 of the reflecting mirror 70. It is reflected once. However, the present inventors have analyzed the projected image of the white fluorescent light in the vicinity of the second focal point f2 in detail, and found that there is a fluorescent component that reaches the second focal point f2 through a different path from the above. . The fluorescence having different routes will be described with reference to FIGS.

  FIGS. 4A and 4B are first and second schematic cross-sectional views respectively illustrating details of the fluorescence path in the vicinity of the first focus and the second focus (focus area) of the reflecting mirror 70 according to the present embodiment. FIG. FIG. 4C is a schematic diagram of the projected image of the fluorescent light on the xy plane in the focal region of the second focal point of reflecting mirror 70 in illumination device 100 according to the present embodiment. In FIG. 4A, it is assumed that the fluorescent light 110 emitted from the phosphor 90 is reflected once at a point P on the reflecting surface 71 of the reflecting mirror 70. Most of the fluorescent component reaching the point P is reflected once by the reflecting surface 71 and is collected at the second focal point f2 of the reflecting mirror 70. However, since the reflecting surface 71 is not a perfect spheroid, only a small part of the fluorescence is scattered by the surface irregularities at the point P, and there is the fluorescence 114 returning to the phosphor 90 as shown by the dotted line in FIG. 4A. I do. In addition, since the surface of the phosphor 90 is not a perfect mirror surface, the fluorescent light 114 returning to the phosphor 90 is further scattered on the surface or inside of the phosphor 90 and changes its traveling direction to the point Q direction on the reflecting surface 71. After being emitted and reflected at the point Q, it reaches the second focal point f2 of the reflecting mirror 70 (see the fluorescent light 115 indicated by a dotted line in FIG. 4A). FIG. 4A illustrates an example of one locus of the fluorescent light 115. As shown in FIG. 4B, the traveling direction of the fluorescent light after being rescattered by the fluorescent material 90 is omnidirectional (180 degrees) as viewed from the surface of the fluorescent material 90. ), The emission angle is wider than the emission characteristic (Lambertian) of the fluorescence by laser light excitation. As a result, the projected image of the fluorescent light at the position f2n near the second focal point f2 (focal area) of the reflecting mirror 70 shown in FIG. 4B is scattered once on the reflecting surface 71 of the reflecting mirror 70 as shown in FIG. 4C. The projected image of the fluorescent light 110 is superimposed on the projected image of the fluorescent light 115 that has been scattered multiple times. The former shows an intensity distribution that directly reflects the intensity distribution of the convergent light 51 (that is, the excitation light) on the light emitting surface 91 of the phosphor 90. In the present embodiment, the region of this intensity distribution is described below as the first intensity distribution. This is referred to as a region 110r. On the other hand, the latter has a smaller intensity than the first intensity distribution region 110r and has a relatively uniform intensity distribution. In the present embodiment, this intensity distribution region is hereinafter referred to as a second intensity distribution region 115r. Name.

  The second intensity distribution region 115r is uniquely determined when the installation direction of the reflecting mirror 70 is determined, but the first intensity distribution region 110r can change according to the irradiation position of the laser light on the phosphor 90. For example, if the irradiation position of the convergent light 51 on the phosphor 90 is shifted from the first focus of the reflecting mirror 70, the projected image of the fluorescent light will not be as shown in FIG. 4C. That is, the center of the first intensity distribution region 110r and the center of the second intensity distribution region 115r are shifted, and the efficiency of condensing fluorescence of the reflecting mirror 70 is reduced. Conversely, according to this configuration, even when the irradiation position of the convergent light 51 on the light emitting surface 91 of the phosphor 90 cannot be directly observed, the projected image of the fluorescent light at the position f2n near the second focal point f2 of the reflecting mirror 70. By observing, the irradiation position of the convergent light 51 can be indirectly observed. This makes it possible to adjust the optical axis extremely easily and with high precision. As described above, when the fluorescence reflectance on the reflecting surface 71 of the reflecting mirror 70 is low, the relative intensity of the second intensity distribution region 115r with respect to the first intensity distribution region 110r is high. That is, the difference in light intensity between the first intensity distribution region 110r and the second intensity distribution region 115r becomes small, and it becomes difficult to distinguish each region. Therefore, the higher the fluorescence reflectance of the reflecting surface 71 of the reflecting mirror 70, the better. For example, the fluorescence reflectance of the reflection surface 71 may be 80% or more. This makes it possible to clearly distinguish the two intensity distribution regions as shown in FIG. 4C. Further, the fluorescence reflectance of the reflection surface 71 may be 90% or more. Thereby, the two intensity distribution regions can be more clearly distinguished.

  As described above, in the present embodiment, the projected image of the fluorescence in the focal region of the second focal point of the reflecting mirror 70 has the first intensity distribution region 110r and the intensity of the fluorescence smaller than that of the first intensity distribution region 110r. And a second intensity distribution region 115r. Further, the first intensity distribution region 110r is included in the second intensity distribution region 115r, and the center of the first intensity distribution region 110r matches the center of the second intensity distribution region 115r. Thus, alignment between the semiconductor laser device 1 that emits a plurality of laser beams, the phosphor 90, and the reflecting mirror 70 can be realized with high accuracy. Further, such alignment can be realized by adjusting the center positions of the first intensity distribution region 110r and the second intensity distribution region 115r. That is, since the first intensity distribution region 110r and the second intensity distribution region 115r can be easily confirmed by visual observation or the like, highly accurate alignment can be easily realized. In addition, by realizing high-precision alignment, the fluorescence collecting efficiency of the reflecting mirror 70 can be increased.

  Note that the center of each intensity distribution region may be appropriately defined. For example, the center may be the center of gravity of each intensity distribution area. In addition, the case where the centers of the respective intensity distribution regions coincide with each other is not limited to the case where the centers completely coincide with each other, but also includes the case where the centers substantially coincide. For example, the distance between the centers may be about 10% or less of the diameter of the first intensity distribution region 110r.

  Further, since the reflection surface 71 has a spheroidal shape, the shape of the first intensity distribution region 110r having a high intensity is closer to a circle and the more uniform the intensity distribution, the more the shape of the fluorescence irradiation region is circular. Close and the intensity distribution is uniform.

  According to the present embodiment, as shown in FIG. 4C, it is possible to realize first intensity distribution region 110r that is substantially inscribed in a circle (in other words, a gap between the circumscribed circle is small). The details will be described with reference to FIGS. Each drawing shows the three-dimensional orthogonal coordinate axes of the x-axis, the y-axis, and the z-axis as in FIGS. FIG. 5 is a perspective view illustrating a schematic configuration of the semiconductor laser light emitting device 19 according to the first embodiment and a plurality of laser light emission modes from the semiconductor laser element 1. The semiconductor laser light emission illustrated in FIGS. 3 shows details of the device 19. In FIG. 5, a semiconductor laser light emitting device 19 is a packaged light emitting device. The semiconductor laser light emitting device 19 includes a semiconductor laser element 1 having a plurality of light emitting regions in one laminated body and a metal cap (can) 12 constituting a package. Prepare. By using such a semiconductor laser element 1, the semiconductor laser light emitting device 19 can be downsized. In the present embodiment, the semiconductor laser device 1 has two light-emitting regions, and two optical waveguides 11a and 11b having stripe widths Wa and Wb, respectively, are formed and arranged in the cap 12. Specifically, the semiconductor laser device 1 is mounted via a submount 2 on a stem 10b arranged on a disk-shaped base 10a. In the present embodiment, the semiconductor laser device 1 is arranged such that the direction of the stripe width Wa of the optical waveguide 11a is the direction of the x-axis. That is, the semiconductor laser element 1 is arranged such that the longitudinal direction (stripe direction) of the optical waveguide 11a is the direction of the z-axis.

  A window glass 13 is attached to the cap 12 so that the laser beams 111a and 111b from the semiconductor laser device 1 can be transmitted. The window glass 13 is an example of a light transmitting member that transmits the laser beams 111a and 111b emitted from the semiconductor laser device 1, and is a plate glass in the present embodiment. The semiconductor laser light emitting device 19 is further provided with an electrode pin 14 for supplying power to the semiconductor laser element 1 from outside.

  The radiation angles of the laser beams 111a and 111b from the semiconductor laser device 1 are different in two orthogonal axes, and the radiation angle in the x-axis direction is smaller than the radiation angle in the y-axis direction.

  In other words, the direction of the stripe width coincides with the direction of the narrow emission angle.

  The distance D between the centers of the two optical waveguides 11a and 11b may be, for example, 100 μm or less. Further, the distance D may be 50 μm or less. Thereby, the semiconductor laser device 1 can be further downsized.

  Next, the aspheric lens 50 of the present disclosure will be described with reference to FIGS. 6 and 7. FIGS. 6 and 7 are schematic views of a yz section and a zx section showing a laser beam path for explaining the operation of the aspheric lens 50 according to the first embodiment. 6 and 7, the same members as those in FIGS. 1 to 5 are denoted by the same reference numerals, and description thereof will be omitted.

  6, an aspheric lens 50 is an optical element that converts a laser beam 111 emitted from the semiconductor laser device 1 as divergent light into convergent light. Since the laser light 111a from the optical waveguide 11a of the semiconductor laser device 1 and the laser light 111b from the optical waveguide 11b are substantially the same in the yz section, the laser light 111 and the laser light 111 are not distinguished from each other. Name. The aspherical lens 50 has a difference in refractive power between the inner and outer circumferences. As for the convergent light from the aspherical lens 50, the paraxial ray 51c (dotted line shown in FIG. 6) of the aspherical lens 50 is condensed on the focal plane fy1. A light ray 51e (a dashed line shown in FIG. 6) passing through the outer peripheral portion of the spherical lens 50 is focused on a position fy2 shifted from the focal plane fy1. The difference between the focal positions on the inner and outer peripheral sides of the aspheric lens 50 is called spherical aberration. Spherical aberration is caused by an increase in refractive power from the center of the aspherical lens 50 toward the peripheral direction. In order to reduce the beam spot on the focal plane as much as possible, it is necessary to eliminate this as much as possible.In general, commercially available aspherical lenses have the aspherical surface of the aspherical lens so that this spherical aberration is infinitely zero. Shape is designed. From this, conversely, by adjusting the aspherical shape, it is possible to intentionally increase the amount of spherical aberration and adjust the focal position of the outer peripheral portion of the lens before and after the focal plane of the paraxial ray.

  When a laser beam having a Gaussian intensity distribution is condensed using an aspheric lens 50 having a spherical aberration, that is, an aspheric lens 50 whose refractive power increases in the outer peripheral direction, a light beam 51e on the outer peripheral side having weak intensity is gathered inside, Due to the effect of overlapping with the paraxial ray 51c, there is a surface on the near side of the focal plane where the light intensity distribution is uniform. The position of the surface where the light intensity distribution is uniform can be adjusted to an arbitrary position between the focal plane fy1 of the paraxial ray and the aspheric lens 50 by changing the amount of spherical aberration of the aspheric lens 50. Can be. The amount of spherical aberration of the aspheric lens 50 can be adjusted by adjusting the refractive power of the outer peripheral portion, and the refractive power of the outer peripheral portion can be adjusted by designing the shape of the aspheric lens 50. In the present embodiment, the phosphor 90 is provided at a position on the z-axis at which the intensity distribution of the laser light is uniform on the y-axis and in the focal region of the first focal point of the reflecting mirror 70. ing.

  As described above, the aspheric lens 50 has a function of making the light intensity distribution uniform in the direction where the spread angle of the two laser beams from the semiconductor laser element 1 is large (that is, the Y-axis direction). It is arranged at a position closer to the aspheric lens 50 than the focal point of the aspheric lens 50. Thereby, the peak intensity of the convergent light on the light emitting surface 91 of the phosphor 90 can be reduced, and a decrease in energy conversion efficiency due to luminance saturation, temperature quenching, and the like can be suppressed. Further, by disposing the phosphor 90 at a position closer to the aspherical lens 50 than the focal point of the aspherical lens 50, uniform intensity formed by superposing the intensity distributions of the two laser beams from the semiconductor laser device 1 is obtained. With the distribution, the phosphor 90 can be irradiated with laser light (convergent light).

  In the schematic diagram of the zx cross section of FIG. 7, the emission end face of the laser beam of the semiconductor laser element 1 is parallel to the main plane of the aspheric lens 50, and the first light emitting region (the optical waveguide 11a of FIG. 5) and the second The light emitting region (the optical waveguide 11b in FIG. 5) is equidistant from the aspheric lens 50. The laser beam 111a (two-dot chain line) from the first light emitting region and the laser beam 111b (dotted line) from the second light emitting region of the semiconductor laser device 1 enter the aspheric lens 50 in a state where they are almost overlapped. The laser beams 111a and 111b incident on the aspherical lens 50 are converted into convergent beams 51a and 51b, respectively, and irradiate the phosphor 90 in an overlapping state. As described above, by using the two laser beams from the semiconductor laser element 1, the degree of freedom in adjusting the intensity distribution of the convergent light in the phosphor 90 can be increased.

  When there is no phosphor 90, the convergent light beams 51a and 51b pass through the position and are condensed while being completely separated at the focal plane fx. In the first embodiment, since the emission angles of the laser beams 111a and 111b on the x-axis are smaller than the emission angles of the laser beam 111 in the y-axis direction shown in FIG. The effect of uniformizing the intensity of the convergent lights 51a and 51b on the x-axis by the spherical lens 50 is smaller than that in the y-axis direction.

  Next, the intensity distribution of the convergent light on the light emitting surface 91 of the phosphor 90 will be described. FIG. 8 is a distribution diagram showing a two-dimensional distribution on the xy plane of the convergent light intensity at the position where phosphor 90 according to the present embodiment is arranged. In FIG. 8, a graph (a) is a diagram of a beam profile on the xy plane showing the shape of the convergent light and its intensity distribution in an inverted gray scale. That is, in the graph (a), the light intensity is displayed using a gray scale from black to white, and the closer to white, the greater the light intensity. In addition, in FIG. 8, a graph (b) is a diagram illustrating a light intensity (integral value) distribution in a horizontal direction (x-axis direction), and a graph (c) is a light intensity (integral value) in a vertical direction (y-axis direction). It is a figure which shows an (integral value) distribution. Graphs (b) and (c) show the light intensity distribution at the positions of the lines AA and BB in graph (a). As shown in FIG. 8, at the position where the phosphor 90 is arranged, the convergent light has a light intensity distribution that is uniform in a top hat shape in both the horizontal direction and the vertical direction. This is because, in the vertical direction, the intensity distribution is made uniform by the action of the aspherical lens 50, and in the horizontal direction, the Gaussian distributions of the light intensities of the two convergent lights 51a and 51b overlap, and the sum is uniform. Because it becomes. That is, the aspheric lens 50 has a function of making the light intensity uniform in the direction in which the divergence angle is large in the horizontal direction and the vertical direction. In the present embodiment, the phosphor 90 is adjusted so as to be arranged at a position where such light intensity distribution can be obtained. In other words, the phosphor 90 is arranged at a position shifted toward the aspheric lens 50 from the focal plane where the paraxial ray of the light passing through the aspheric lens 50 forms an image.

  As an adjustment method for obtaining a uniform light intensity distribution other than the position adjustment of the phosphor 90, a method of fixing the position of the phosphor 90 and adjusting the distance between the semiconductor laser element 1 and the aspherical lens 50. There is. Specifically, by adjusting the position of the semiconductor laser element 1 in the z-axis direction or adjusting the position of the aspherical lens 50 in the z-axis direction, the position of the focal plane fx of the two convergent lights 51a and 51b is adjusted. Change. Thus, the degree of overlap between the two convergent light beams 51a and 51b may be changed and adjusted so that a uniform light intensity distribution as shown in FIG.

  The aspheric lens 50 used in the present embodiment is a lens in which spherical aberration is optimized so that the light intensity distribution in the vertical direction is uniform at the installation position of the phosphor 90. The spherical aberration of the aspheric lens 50 is optimized in accordance with the vertical divergence angle of the laser light emitted from the semiconductor laser device 1.

  The uniform intensity distribution described above includes not only a distribution in which the intensity is completely uniform but also a distribution in which the intensity is substantially uniform. For example, a uniform intensity distribution means a distribution in which the change in intensity is within 10%.

  As described above, in the present embodiment, by arranging the phosphor 90 at a position shifted from the focal point of the aspherical lens 50, the light density of the convergent light on the phosphor 90 can be suppressed. For this reason, it is possible to suppress the energy conversion efficiency of the phosphor 90 from being lowered due to luminance saturation. Further, by using the two laser beams from the semiconductor laser device 1, the degree of freedom in adjusting the intensity distribution of the convergent light in the phosphor 90 can be increased. For this reason, by forming an intensity distribution suitable for the shape of the reflecting mirror 70, the illuminance uniformity of the illumination light emitted from the illumination device 100 can be improved. In addition, the above effects can be realized without complicating the configuration of the lighting device 100.

[1-3. Summary]
As described above, the illuminating device 100 according to the present embodiment includes the semiconductor laser element 1 that emits a plurality of laser beams, and the aspheric lens 50 that receives the plurality of laser beams and converts the incident plurality of laser beams into convergent light. And a phosphor 90 that emits fluorescence when convergent light is irradiated as excitation light, and a reflector 70 that has a first focus and a second focus and reflects fluorescence. The phosphor 90 is located in a focal region of the first focal point of the reflecting mirror 70 and at a position shifted from the focal point of the aspherical lens 50 in the optical axis direction of the convergent light.

  By arranging the phosphor 90 at a position deviated from the focal point of the aspherical lens 50, the light density of the phosphor 90 can be suppressed. For this reason, it is possible to suppress the energy conversion efficiency of the phosphor 90 from being lowered due to luminance saturation. Further, by using a plurality of laser beams, the degree of freedom in adjusting the intensity distribution of the convergent light (excitation light) in the phosphor 90 can be increased. For this reason, by forming an intensity distribution suitable for the shape of the reflecting mirror 70, the illuminance uniformity of the illumination light emitted from the illumination device 100 can be improved. In addition, the above effects can be realized without complicating the configuration of the lighting device, for example, as compared with the related art disclosed in Patent Document 1.

  In the illumination device 100, the projected image of the fluorescent light in the focal region of the second focal point of the reflecting mirror 70 has the first intensity distribution region 110r and the second fluorescent light intensity smaller than that of the first intensity distribution region 110r. And an intensity distribution region 115r. The first intensity distribution region 110r may be included in the second intensity distribution region 115r, and the center of the first intensity distribution region 110r may coincide with the center of the second intensity distribution region 115r.

  With this configuration, alignment between the semiconductor laser device 1 that emits a plurality of laser beams, the phosphor 90, and the reflecting mirror 70 can be realized with high accuracy. Further, such alignment can be realized by adjusting the center positions of the first intensity distribution region 110r and the second intensity distribution region 115r. That is, since the first intensity distribution region 110r and the second intensity distribution region 115r can be easily confirmed by visual observation or the like, highly accurate alignment can be easily realized. In addition, by realizing high-precision alignment, the fluorescence collecting efficiency of the reflecting mirror 70 can be increased.

  Further, the aspheric lens 50 may perform beam shaping such that the intensity distribution of the laser light from the plurality of light emitting regions becomes uniform on the light emitting surface 91 of the phosphor 90. For example, the focal position of the outer peripheral portion of the lens may be shifted to a position closer to the aspheric lens 50 than the focal plane of the paraxial ray of the aspheric lens 50.

  As described above, since the phosphor 90 is uniformly excited by the convergent light, the peak intensity of the convergent light on the convergent light irradiation surface of the phosphor 90 can be reduced, and the energy conversion efficiency of the phosphor such as luminance saturation and temperature quenching can be reduced. Can be suppressed. Further, in the present embodiment, the degree of freedom of adjusting the intensity distribution of the convergent light (that is, the intensity distribution of the excitation light) in the phosphor 90 is high, and the shape of the irradiation spot of the convergent light can be made closer to a circle. For this reason, the affinity with the reflective surface 71 having a spheroidal shape is good, and high illuminance uniformity can be obtained in the fluorescence irradiation area.

  In the lighting device 100, the semiconductor laser element 1 may have a plurality of light emitting regions in one stacked body.

  Thus, the size of the laser light source can be reduced.

  In the lighting device 100, the aspheric lens 50 has a function of equalizing the light intensity distribution in the direction in which the divergence angles of the plurality of laser beams are large, and the phosphor 90 is more aspheric than the focal point of the aspheric lens 50. It may be arranged at a position close to the lens 50.

  As described above, by uniforming the light intensity distribution in the direction in which the divergence angle of the plurality of laser beams is large, the peak intensity of the laser beam on the light emitting surface 91 of the phosphor 90 can be reduced, and the luminance saturation and temperature quenching can be achieved. It is possible to suppress a decrease in energy conversion efficiency due to the above. In addition, by disposing the phosphor 90 at a position closer to the aspheric lens 50 than the focal point of the aspheric lens 50, the phosphor 90 has a uniform intensity distribution formed by overlapping the intensity distributions of a plurality of laser beams. Can be irradiated with a plurality of laser beams.

  In the lighting device 100, the reflecting mirror 70 may have a spheroidal reflecting surface 71.

  Thereby, the fluorescent light emitted from the phosphor 90 arranged in the focal region of the first focal point can be focused on the second focal point. Further, since the fluorescent light reflected by the reflecting mirror 70 once intersects at the second focal point, the supporting member 80 for supporting the phosphor 90 and the like can be used as compared with the case where the fluorescent light is emitted as parallel light by the paraboloidal reflecting mirror. Can be suppressed from being formed on the fluorescence irradiation surface.

(Embodiment 2)
[2-1. Configuration of lighting device]
Next, a lighting device 200 according to Embodiment 2 will be described with reference to FIGS. Each drawing shows the three-dimensional orthogonal coordinate axes of the x-axis, the y-axis, and the z-axis as in FIGS. FIG. 9 is a yz cross-sectional view illustrating a schematic configuration of a lighting device 200 according to Embodiment 2. The same members as those of the lighting device 100 of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. The only difference between the illumination device 200 in FIG. 9 and the illumination device 100 in the first embodiment is the configuration of an optical member for shaping the laser beam and irradiating the phosphor 90 with the laser beam. An optical lens 55 having a minute lens region in which the minute lenses are formed is used.

[2-2. Operation of lighting device]
Next, the operation of lighting device 200 according to Embodiment 2 will be described with reference to FIGS. Also in the present embodiment, the operation of exciting the phosphor 90 with laser light to generate white fluorescent light 110 and 115 and projecting the white fluorescent light in a desired direction by the reflecting mirror 70 is described with reference to FIGS. This is the same as Embodiment 1 shown in FIG. 4B. Here, how the laser light from the semiconductor laser light emitting device 19 is beam-shaped and irradiated on the light emitting surface 91 of the phosphor 90 with uniform intensity will be described together with the function of the optical lens 55 having a minute lens region.

  10A, 10B, and 10C are a plan view, a first cross-sectional view, and a second cross-sectional view, respectively, illustrating a schematic configuration of the optical lens 55 according to the second embodiment. FIG. 10A is a plan view of the optical lens 55 of the plurality of laser beams emitted from the semiconductor laser light emitting device 19 when viewed in the optical axis direction (viewed in the z-axis direction). FIG. 10B is a cross-sectional view taken along the line 10B-10B in FIG. It is a schematic diagram, FIG. 10C is a schematic diagram of 10C-10C cross section of FIG. 10A.

  As shown in FIG. 10A, the optical lens 55 has a minute lens region 55R in which a plurality of minute lenses 55a, 55b, 55c, 55d, 55e, 55f, 55g, 55h, and 55i are formed. Note that a plurality of hexagons in the minute lens region 55R shown in FIG. 10A each indicate a minute lens, and only a part of the hexagon is denoted by a reference numeral.

  In the optical lens 55 according to the present embodiment shown in FIG. 10A, each of the plurality of minute lenses has a different focus. That is, each micro lens is formed such that the condensing position of the laser light converted into the convergent light by the plurality of micro lenses of the optical lens 55 is different from each other. In the present embodiment, the condensing position of the laser light is arranged between the phosphor 90 and the optical lens 55.

  As shown in FIG. 10A, the shape of at least a part of the plurality of microlenses when viewed in the optical axis direction of the plurality of laser beams (that is, when viewed in the z-axis direction in FIG. 10A) is a hexagonal shape. Thereby, the gap between the adjacent minute lenses can be reduced to the minimum. Therefore, the area of the gap that does not act as a lens can be minimized, so that a plurality of laser beams can be more efficiently used as excitation light.

The short axis width W1 and the long axis width W2 of the hexagon shown in FIG. 10A are set by the shape of the laser emission pattern from one light emitting region of the semiconductor laser light emitting device 19 of FIG. More specifically, the vertical width is set according to the ratio of the horizontal width in the x-axis direction to the vertical width in the y-axis direction defined by 1 / e ² of the laser light intensity distribution of the laser light 111a or 111b in FIG. / Horizontal width = W2 / W1. Further, as shown in FIGS. 10B and 10C, the minute lens region 55R has a concave-convex shape having a sawtooth cross section, and each of the convex portions forms a minute lens. As shown in FIGS. 10A to 10C, the optical lens 55 is a Fresnel lens having a plurality of minute lenses arranged in an array. The uneven shape of the minute lens region 55R is provided on the surface of the optical lens 55 on the side of the semiconductor laser light emitting device 19.

  Subsequently, a beam shaping function in the x-axis direction of the illumination device 200 will be described with reference to FIG. FIG. 11 is a schematic diagram of a zx cross section showing a laser beam path for explaining the function of the optical lens 55 according to the second embodiment. Sectional views (a), (b), and (c) of FIG. 11 show the paths of laser light incident on the microlenses 55a, 55c, and 55e, respectively.

  In the sectional view (a) of FIG. 11, the end face on the emission side of the laser beam of the semiconductor laser element 1 is parallel to the main plane of the optical lens 55 having a plurality of microlenses, and the first light emitting region (the optical waveguide 11 a of FIG. 5). ) And the second light emitting region (the optical waveguide 11b in FIG. 5) are equidistant from the minute lens 55a. The laser beam 111a (dotted line) from the first light-emitting region and the laser beam 111b (solid line) from the second light-emitting region of the semiconductor laser device 1 enter the microlens 55a in a state where they are almost overlapped. The laser beams 111a and 111b that have entered the microlenses 55a are converted into convergent beams 51aa and 51ba, respectively, and are once collected at the focal points 52aaf and 52baf, then diverge again and enter the phosphor 90, and the area x1 And x2 are excited. The shape of the minute lens 55a is optimized so that the region x1 and the region x2 do not overlap.

  Similarly, in the cross-sectional view (b) of FIG. 11, the convergent lights 51ac and 51bc emitted from the minute lens 55c are condensed at the focal points 52acf and 52bcf, respectively, and then diverge again and enter the phosphor 90. , Excite regions x1 and x2.

  Similarly, in the cross-sectional view (c) of FIG. 11, the convergent light beams 51ae and 51be emitted from the microlenses 55e are condensed at the focal points 52aef and 52bef, respectively, then diverge again and enter the phosphor 90. , Excite regions x1 and x2. Although not particularly shown, similarly, at the minute lenses 55b and 55d, the respective convergent lights enter the phosphor 90 and excite the regions x1 and x2.

  Comparing the focal positions of the individual microlenses with the cross-sectional views (a) to (c) of FIG. 11, the focal points 52acf and 52bcf of the microlenses 55c (see the cross-sectional view (b) of FIG. 11) are the focal points 52aaf of the microlenses 55a. , 52baf (see the cross-sectional view (a) of FIG. 11), it can be seen that it is located closer to the phosphor 90. The dashed lines shown in the cross-sectional views (a) to (c) of FIG. 11 indicate the positions of the focal points 52aaf and 52baf in the z-axis direction. The focal points 52aef and 52bef (see the sectional view (c) of FIG. 11) of the minute lens 55e are closer to the phosphor 90 than the focal points 52acf and 52bcf (see the sectional view (b) of FIG. 11) of the minute lens 55c. It turns out that it is located. As described above, each of the plurality of microlenses has a different focal point, and the phosphor 90 is disposed at a position farther from the optical lens 55 than these focal points, and each laser passing through the focal point of each of the plurality of microlenses. The light overlaps on the light emitting surface of the phosphor 90.

  Next, the intensity distribution of the convergent light generated by the optical lens 55 in the x-axis direction will be described with reference to FIGS. 12A and 12B. FIGS. 12A and 12B are schematic diagrams of one-dimensional profiles in the x-axis direction at the positions of the optical lens 55 and the phosphor 90 of the laser beam intensity according to the present embodiment, respectively. 12A and 12B, the light intensity distribution when laser light 111a emitted from one optical waveguide 11a of semiconductor laser element 1 is split by each microlens, and split laser light 111a is converted into convergent light. The intensity distribution when converted and condensed on the area x1 of the phosphor 90 will be described. FIG. 12A shows the intensity distribution (x-axis direction) of the laser beam 111a from the optical waveguide 11a at the position of the optical lens 55, and FIG. 12B shows the intensity distribution of the convergent light from each microlens on the light emitting surface 91 of the phosphor 90. (In the x-axis direction). The laser beam 111a is divided into convergent beams 51aa, 51ab, 51ac, 51ad, and 51ae by five microlenses as shown in FIG. 12A, and overlaps again in the area x1 of the phosphor 90 as shown in FIG. 12B. The sum of each converged light in FIG. 12B has a profile with a uniform intensity distribution as shown by the solid line. As shown in FIG. 12B, for example, a convergent light 51ad having an intensity distribution inclined upward to the right and a convergent light 51ae having an intensity distribution inclined downward to the right overlap in the region x1. Thereby, at least a part of the gradient of the intensity distribution is canceled out and becomes uniform. Similarly, when the convergent light 51ab and the convergent light 51ac having the inclined intensity distribution overlap in the region x1, the inclination of the intensity distribution is canceled. Thus, convergent light having a substantially uniform intensity distribution in the region x1 can be obtained. Although not particularly shown, the laser beam 111b from the other optical waveguide 11b is similarly shaped into a uniform profile of intensity distribution as shown in FIG. 12B in the region x2 of the phosphor 90.

  Subsequently, a beam shaping function in the y-axis direction of the illumination device 200 will be described with reference to FIG. FIG. 13 is a schematic diagram of a yz section showing a laser beam path for explaining the function of the optical lens 55 according to the second embodiment. The cross-sectional views (a), (b), and (c) of FIG. 13 show the paths of the laser light incident on the minute lenses 55a, 55f, and 55h, respectively.

  In FIG. 13A, the emission end face of the laser beam of the semiconductor laser device 1 is parallel to the main plane of the optical lens 55 having a plurality of microlenses, and is in the first light emitting region (the optical waveguide 11a of FIG. 5). ) And the second light emitting region (the optical waveguide 11b in FIG. 5) are equidistant from the minute lens 55a. Since the laser light 111a from the first light emitting region and the laser light 111b from the second light emitting region of the semiconductor laser device 1 are substantially the same in the yz section, the laser light 111 and the laser light 111 are not distinguished from each other. Name. In the cross-sectional view (a) of FIG. 13, the component of the laser beam 111 that has entered the microlens 55 a is converted into convergent light 51 ay, once collected at the focal point 52 ayf, and then diverges again to the phosphor 90. The incident light excites the region y1.

  Similarly, also in the cross-sectional view (b) of FIG. 13, the convergent light 51fy emitted from the minute lens 55f is condensed at the position of the focal point 52fyf, then diverges again and enters the phosphor 90 to excite the region y1. I do.

  Similarly, also in the cross-sectional view (c) of FIG. 13, the convergent light 51hy emitted from the minute lens 55h is condensed at the position of the focal point 52hyf, then diverges again and enters the phosphor 90 to excite the region y1. I do. Although not particularly shown, similarly, also in the minute lenses 55g and 55i, respective convergent lights enter the phosphor 90 and excite the y1 region.

  Comparing the focal positions of the individual microlenses with the cross-sectional views (a) to (c) of FIG. 13, it can be seen that the focal point 52fyf of the microlens 55f is located closer to the phosphor 90 than the focal point 52ayf of the microlens 55a. . Also, it can be seen that the focal point 52hyf of the minute lens 55h is located closer to the phosphor 90 than the focal point 52fyf of the minute lens 55f. As described above, each of the plurality of microlenses has a different focal point, the phosphor 90 is disposed closer to the phosphor 90 than these focal points, and each laser beam passing through the focal point in each of the microlenses is And the light emitting surface of the phosphor 90. The individual microlenses are designed to have no astigmatism. For example, the focal points 52aaf and 52baf of the microlens 55a in the x-axis direction (see the cross-sectional view (a) in FIG. 11) and the focal points in the y-axis direction The position on the z-axis of 52ayf (see the sectional view (a) of FIG. 13) coincides. Accordingly, by providing the opening 75 of the reflecting mirror 70 near the focal point of each microlens, the area of the opening 75 can be reduced, so that the fluorescence loss in the opening 75 of the reflecting mirror 70 can be reduced.

  Subsequently, the intensity distribution of the convergent light generated by the optical lens 55 in the y-axis direction will be described with reference to FIGS. 14A and 14B. 14A and 14B are schematic one-dimensional profiles of the positions of the optical lens 55 and the phosphor 90 of the laser light intensity in the y-axis direction according to the present embodiment. 14A and 14B, the light intensity distribution when the laser light 111 emitted from the optical waveguides 11a and 11b of the semiconductor laser device 1 is split by each micro lens, and the split laser light 111 is converted into convergent light. The light intensity distribution when converted and condensed on the area y1 of the phosphor 90 will be described. FIG. 14A shows the intensity distribution (y-axis direction) of the laser beam 111 from the optical waveguide 11a at the position of the optical lens 55, and FIG. 14B shows the intensity distribution of the convergent light from each minute lens in the region y1 of the phosphor 90 ( (y-axis direction). The laser light 111 is divided into convergent lights 51ay, 51fy, 51gy, 51hy, and 51iy by five microlenses as shown in FIG. 14A, and overlaps again in the area y1 of the phosphor 90 as shown in FIG. 14B. As a result, similarly to the intensity distribution of the convergent light in the x-axis direction described with reference to FIGS. 12A and 12B, the intensity distribution of the convergent light in the region y1 of the phosphor 90 is substantially as shown by the solid line in FIG. 14B. It becomes uniform uniformly.

  An example of the intensity distribution of the convergent light on the light emitting surface 91 of the phosphor 90 obtained in the lighting device 200 designed as described above will be described with reference to FIG.

  FIG. 15 is a graph showing the intensity distribution of convergent light in phosphor 90 of lighting device 200 according to Embodiment 2. The graphs (a) and (d) of FIG. 15 show that the laser light (the laser light 111a shown in FIG. 11 and the laser light 111 shown in FIG. 13) from the optical waveguide 11a is an optical lens 55 having a plurality of microlenses. 7A and 7B are a two-dimensional intensity distribution display and a three-dimensional intensity distribution display of the light intensity distribution of the convergent light converted at step S1 on the light emitting surface 91. The graphs (b) and (e) of FIG. 15 show that the laser light (the laser light 111b shown in FIG. 11 and the laser light 111 shown in FIG. 13) from the optical waveguide 11b is an optical lens 55 having a plurality of minute lenses. 5A and 5B are a two-dimensional intensity distribution display and a three-dimensional intensity distribution display of the light intensity distribution of the excitation light converted at step S1 on the light emitting surface 91. Graphs (c) and (f) of FIG. 15 show optical lenses having microlenses for the laser beams of the optical waveguides 11a and 11b (the laser beams 111a and 111b shown in FIG. 11 and the laser beam 111 shown in FIG. 13), respectively. 7A and 7B are a two-dimensional intensity distribution display and a three-dimensional intensity distribution display of the light intensity distribution of the excitation light converted at 55 on the light emitting surface 91. Each of them is a view from the optical lens 55 side, and shows a two-dimensional intensity distribution display and a three-dimensional intensity distribution display of the light intensity distribution. In the two-dimensional intensity distribution displays of the graphs (a) to (c), the light intensity distribution is shown in an inverted gray scale.

  As shown in graphs (a) and (d) of FIG. 15, and (b) and (e), the fluorescence of the convergent light emitted from each optical waveguide and converted by the optical lens 55 having the minute lens region 55R. The light intensity distribution on the light emitting surface 91 of the body 90 is made uniform. Further, as shown in graphs (c) and (f) of FIG. 15, each convergent light is designed to partially overlap the light emitting surface 91 of the phosphor 90, and one uniform light as a whole is obtained. It has a light intensity distribution.

  Thus, one light intensity distribution can be obtained by the optical lens 55 having a plurality of microlenses. Furthermore, the light intensity distribution can be adjusted by appropriately designing the shape of each microlens. Thereby, a light intensity distribution suitable for the reflecting mirror 70 can be formed, and thus the illumination device 200 that can emit illumination light with high uniformity can be realized.

[2-3. Summary]
As described above, in the illumination device 200 according to the present embodiment, the optical lens 55 has the minute lens region 55R in which the plurality of minute lenses are formed, and each of the plurality of minute lenses has a different focus. The phosphor 90 is arranged at a position farther from the optical lens 55 than the focal point of each of the plurality of microlenses. In addition, a plurality of components of the two laser beams, which are respectively condensed by the plurality of microlenses, overlap on the light emitting surface 91 of the phosphor 90, so that the two laser beams have a large spread angle in the light emitting surface 91. Each light intensity distribution in the smaller direction is made uniform.

  Thereby, the peak intensity of the laser beam on the light emitting surface 91 of the phosphor 90 can be reduced, and a decrease in energy conversion efficiency due to luminance saturation, temperature quenching, and the like can be suppressed. Further, by providing the opening 75 of the reflecting mirror 70 near the focal point of each minute lens, the opening area can be reduced, so that the fluorescence reflection loss due to the opening 75 can be reduced and the energy efficiency can be increased. Further, by appropriately designing the minute lens region 55R, the shape of the intensity distribution of the convergent light on the light emitting surface 91 of the phosphor 90 can be made closer to a circle. For this reason, it is possible to emit fluorescent light having a good light distribution characteristic from the phosphor 90 with good affinity with the reflecting surface 71 of the reflecting mirror 70 having a spheroidal shape. Therefore, it is possible to realize the lighting device 200 having high illuminance uniformity in the fluorescence irradiation area.

  In the lighting device 200, the shape of at least a part of the plurality of minute lenses of the optical lens 55 in the optical axis direction of the laser light (that is, in the z-axis direction) may be a hexagonal shape.

  Thereby, the gap between the adjacent minute lenses can be reduced to the minimum. Therefore, the area of the gap that does not act as a lens can be minimized, so that the two laser beams from the semiconductor laser device 1 can be more efficiently used as excitation light.

  Further, in the lighting device 200 according to the present embodiment, the semiconductor laser device 1 having two optical waveguides is used. However, even when three or more optical waveguides are provided, the microlenses emitted from the adjacent optical waveguides are used. One uniform light intensity distribution is designed by designing the convergent light converted by the optical lens 55 having the region 55R so that a part of the intensity distribution on the light emitting surface 91 of the phosphor 90 overlaps with each other. A small lighting device having

  Further, in the illumination device 200 according to the present embodiment, the laser light from the semiconductor laser light emitting device 19 is configured to be directly incident on the optical lens 55 having the minute lens region 55R. A collimator lens may be added between 55.

(Modification of Second Embodiment)
Next, a modified example of the lighting device 200 according to Embodiment 2 will be described with reference to the drawings.

[2A-1. Configuration of lighting device]
The illuminating device according to this modification has the same configuration as the illuminating device 200 according to the second embodiment, except that the shape of the plurality of minute lenses of the optical lens is not hexagonal but rectangular (rectangular). . Hereinafter, the configuration of the optical lens according to the present modification will be mainly described. 16A, 16B, and 16C are a plan view, a first cross-sectional view, and a second cross-sectional view, respectively, illustrating a schematic configuration of the optical lens 155 according to the present modification. FIG. 16A is a plan view of the optical lens 155 of the plurality of laser beams emitted from the semiconductor laser light emitting device 19 when viewed in the optical axis direction (viewed in the z-axis direction). FIG. It is a schematic diagram, FIG. 16C is a schematic diagram of 16C-16C cross section of FIG. 16A.

  As shown in FIG. 16A, the optical lens 155 according to the present modification has a minute lens region 155R in which a plurality of minute lenses 155a, 155b, 155c, 155d, 155e, 155f, 155g, 155h, and 155i are formed. In this modification, a plurality of squares in the minute lens region 155R shown in FIG. 16A each indicate a minute lens, and only a part thereof is denoted by a reference numeral.

As shown in FIG. 16A, the shape of at least a part of the plurality of microlenses as viewed in the optical axis direction of the plurality of laser beams is a quadrangular shape. In the present embodiment, the shape of the plurality of microlenses as viewed in the optical axis direction (that is, as viewed in the z-axis direction in FIG. 16A) is a square shape. Thereby, the gap between the adjacent minute lenses can be reduced to the minimum. Therefore, the area of the gap that does not act as a lens can be minimized, so that a plurality of laser beams can be more efficiently used as excitation light. The short axis width W1 and the long axis width W2 of the quadrangle shown in FIG. 16A are set according to the shape of the laser emission pattern from one light emitting region of the semiconductor laser light emitting device 19 in FIG. More specifically, the laser beam 111a or 111b of FIG. 5 is provided with a ratio of the horizontal width in the x-axis direction and the vertical width in the y-axis direction defined by 1 / e ² of the laser light intensity distribution, / Horizontal width = W2 / W1. As shown in FIGS. 16B and 16C, the microlens region 155R has a saw-tooth cross section, and each of the protruding portions forms a microlens. As shown in FIGS. 16A to 16C, the optical lens 155 is a Fresnel lens having a plurality of minute lenses arranged in an array. The uneven shape of the minute lens region 155R is provided on the surface of the optical lens 155 on the semiconductor laser light emitting device 19 side.

[2A-2. Operation of lighting device]
In this modification, the operation of the device is the same as that of the configuration, and a description of the same operation as that of the illumination device 200 of Embodiment 2 will be omitted. In the second embodiment, the two-dimensional intensity distribution on the xy plane of the convergent light on the light emitting surface of the phosphor 90 is hexagonal, but in this modification, it is quadrangular. As a result, the shape of the first intensity distribution region 110r at the position f2n near the second focal point (focal region) of the reflecting mirror 70 is also different from that of the second embodiment. The first intensity distribution region 110r according to the present modification will be described with reference to FIG. FIG. 17 is a schematic diagram of a projected image of the fluorescence on the xy plane in the vicinity of the second focal point (focal region) of the reflecting mirror 70 of the illumination device according to the present modification. As shown in FIG. 17, in the present modification, the first intensity distribution region 110r also has a square shape like the shape of the minute lens. Also in this case, by making the shape of the first intensity distribution region 110r close to, for example, a square, the affinity with the reflection surface 71 having a spheroidal shape can be increased. Thereby, high illuminance uniformity can be obtained in the fluorescence irradiation area of the illumination device according to the present modification.

[2A-3. Summary]
As described above, in the lighting device according to the modified example of the present embodiment, the shape of at least a part of the plurality of minute lenses of optical lens 155 in the optical axis direction is a quadrangle.

  Thereby, the gap between the adjacent minute lenses can be reduced to the minimum. Therefore, the area of the gap that does not act as a lens can be minimized, so that the two laser beams from the semiconductor laser device 1 can be more efficiently used as excitation light. Further, since the laser light intensity distribution on the light emitting surface 91 of the phosphor 90 can be made substantially square, it has good affinity with the reflecting mirror 70 having the spheroidal reflecting surface 71 and is high in the fluorescence irradiation area. Illuminance uniformity can be obtained.

  As described above, the light emitting device and the lighting device according to the present disclosure have been described based on the embodiments and the modifications, but the present disclosure is not limited to the above embodiments and the modifications.

  For example, in the above embodiment, the illumination device is configured to emit white light by using the blue phosphor and the yellow phosphor, but the present invention is not limited to this. For example, it may be configured to emit white light using a blue phosphor, a red phosphor, and a green phosphor, or may be configured to emit white light with a phosphor of any other combination. Good.

  Further, in each of the above embodiments, the semiconductor laser element 1 emits two laser beams, but the number of lasers emitted by the semiconductor laser element 1 is not limited to two, and may be three or more. Further, the plurality of light emitting regions of the semiconductor laser device 1 may be arranged in a line, or may be arranged in other modes. For example, the plurality of light emitting regions of the semiconductor laser device 1 may be arranged in a matrix.

  Further, in the first embodiment, the configuration is adopted in which the intensity of the convergent light is uniform at a position closer to the aspheric lens 50 than the focal point of the aspheric lens 50, but the configuration of the present disclosure is not limited to this. By adjusting the shape of the aspherical lens 50, the arrangement of the plurality of laser beams of the semiconductor laser element 1, and the like, the intensity of the convergent light can be made uniform at a position farther from the aspherical lens 50 than the focal point of the aspherical lens 50. It is possible.

  Further, in the second embodiment, the configuration in which the intensity of the convergent light is uniform at a position farther from the optical lens 55 than the focal point of the optical lens 55 is adopted, but the configuration of the present disclosure is not limited to this. By adjusting the shape and arrangement of the microlenses of the optical lens 55, the arrangement of the plurality of laser beams of the semiconductor laser element 1, and the like, the intensity of the convergent light can be made uniform at a position closer to the aspheric lens 50 than the focal point of the optical lens 55. It is also possible.

  For example, a form obtained by performing various modifications that can be conceived by those skilled in the art to each of the embodiments and the modified examples, and components and functions in each of the embodiments and the modified examples arbitrarily without departing from the spirit of the present disclosure. A form realized by combination is also included in the present disclosure.

  The lighting device of the present disclosure can be applied to industrial lighting such as high ceiling spot lighting and store lighting used in factories or gymnasiums.

1 semiconductor laser device (laser light source)
2 Submount 10a Base 10b Stem 11a, 11b Optical Waveguide 12 Cap 13 Window Glass 14 Electrode Pin 19 Semiconductor Laser Light Emitting Device 20 Metal Base Member 30 Heat Sink 40 Lens Holding Member 50 Aspherical Lens (Optical Lens)
51, 51a, 51b, 51aa, 51ab, 51ac, 51ad, 51ae, 51ay, 51ba, 51bc, 51be, 51fy, 51gy, 51hy, 51iy Convergent light 51c Paraxial light 51e Light 52aaf, 52acf, 52aef, 52ayf, 52baf52baf52 , 52bef, 52fyf, 52hyf Focus 55, 155 Optical lens 55a, 55b, 55c, 55d, 55e, 55f, 55g, 55h, 55i, 155a, 155b, 155c, 155d, 155e, 155f, 155g, 155h, 155i Micro lens 55R 155R minute lens area 60 connecting member 70, 1114, 1208 reflecting mirror 71 reflecting surface 75 opening 80 supporting member 85 high reflection substrate 90, 1112 phosphor 91 light emitting surface 100, 200 lighting Apparatus 110, 114, 115 Fluorescence 110r First intensity distribution area 111, 111a, 111b Laser light 115r Second intensity distribution area 1020 Light source unit 1030 Enlarged view 1102 Laser module 1104 Laser diode 1106 Substrate 1110 Lens 1116 Light transmission section 1204 Transmission Member 1206 housing

Claims (7)

A laser light source for emitting a plurality of laser lights,
An optical lens into which the plurality of laser beams are incident and converts the incident plurality of laser beams into convergent light,
A phosphor that emits fluorescence when the convergent light is irradiated as excitation light,
A reflecting mirror having a first focal point and a second focal point and reflecting the fluorescent light;
The illumination device, wherein the phosphor is disposed in a focal region of the first focal point of the reflecting mirror, and is displaced from a focal point of the optical lens in an optical axis direction of the converged light. The projected image of the fluorescence in the focal region of the second focal point of the reflector is a first intensity distribution region and a second intensity distribution region in which the intensity of the fluorescence is smaller than the first intensity distribution region. Have
The first intensity distribution area is included in the second intensity distribution area, and a center of the first intensity distribution area coincides with a center of the second intensity distribution area. Lighting equipment. The lighting device according to claim 1, wherein the laser light source is a semiconductor laser device having a plurality of light-emitting regions in one stacked body. The optical lens is an aspherical lens, and has a function of equalizing a light intensity distribution in a direction in which a divergence angle of the plurality of laser beams is large,
The lighting device according to claim 1, wherein the phosphor is disposed at a position closer to the optical lens than a focal point of the optical lens. The optical lens has a minute lens region in which a plurality of minute lenses are formed,
Each of the plurality of microlenses has a different focus,
The phosphor is disposed at a position farther from the optical lens than a focal point of each of the plurality of microlenses,
In the plurality of laser beams, a plurality of components respectively condensed by the plurality of microlenses overlap on a light emitting surface of the phosphor, so that a direction in which the divergence angle of the plurality of laser beams is large on the light emitting surface and The lighting device according to any one of claims 1 to 3, wherein each light intensity distribution in a small direction is made uniform. The lighting device according to claim 5, wherein a shape of at least a part of the plurality of microlenses as viewed in the optical axis direction of the plurality of laser beams is a square shape or a hexagonal shape. The lighting device according to claim 1, wherein the reflecting mirror has a spheroidal reflecting surface.

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