JP7051810B2 - Lighting equipment - Google Patents

Description

The present disclosure relates to a lighting device, and more particularly to a lighting device that utilizes fluorescence emitted from a phosphor by irradiating the phosphor with a laser beam from a laser light source.

In recent years, technological development of a lighting device that irradiates a phosphor with a laser beam from a semiconductor laser element and uses the wavelength-converted fluorescence as illumination light has been actively developed. As such a lighting device, the lighting device shown in Patent Document 1 is conventionally 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 showing a schematic configuration of a conventional lighting device disclosed in Patent Document 1.

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

As shown in FIG. 18, the light source unit 1020 is a laser module 1102, which is a laser diode 1104 that oscillates a laser beam mounted on a substrate 1106 and a lens 1110 that captures and condenses the laser beam emitted from the laser diode 1104. It is composed of. Further, a rotating parabolic reflector 1208 and a transmission member 1204 are provided in a part of the housing 1206. Further, as shown in the enlarged view 1030, the reflecting mirror 1114 and the phosphor 1112 are laminated and formed on a part of the transmission member 1204. The excitation light emitted from the laser module 1102 is guided to the concave side of the reflecting mirror 1208 from the light transmitting portion 1116 provided in a part of the reflecting mirror 1208, and excites the phosphor 1112 to generate white fluorescence. Further, the phosphor 1112 is positioned at the focal point F of the reflecting mirror 1208, and the generated white fluorescence is converted into substantially parallel rays and emitted to the outside of the housing 1206.

Japanese Unexamined Patent Publication No. 2005-150041

However, in the configuration of the conventional light source unit 1020 shown in FIG. 18, when the high-power laser light is narrowed down on the phosphor for the purpose of producing high-brightness and high-power illumination light, the light density becomes too high. , The excited electrons are depleted. Therefore, so-called luminance saturation occurs in which the energy conversion efficiency of the phosphor is saturated. In addition, the temperature of the phosphor may be extinguished as the temperature rises. Further, when the temperature of the phosphor exceeds the heat resistant temperature, there is a problem that the fluorescent substance itself is burnt and deteriorates. Further, in Patent Document 1, although the light distribution pattern control in the white light irradiation region is mentioned, the specific disclosure of the illuminance uniformity is not made. Furthermore, a reflecting mirror is provided on the substrate side of the phosphor, so that the phosphor cannot be directly observed from the outside of the housing, and the size of the phosphor is larger than the emission area of the laser diode, which is usually considered to be 100 μm ² or less. Is set to be even smaller, so there is a problem that it is very difficult to align the laser module, the phosphor, and the rotating parabolic reflector with each other.

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

In order to solve the above problems, one aspect of the lighting apparatus according to the present disclosure is a laser light source that emits a plurality of laser beams, and the plurality of laser beams are incident on the light, and the incident light is converged. It is provided with an optical lens that converts to The phosphor is arranged in the focal region of the first focal point of the reflecting mirror at a position deviated from the focal point of the optical lens in the optical axis direction of the focused light.

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

Further, in one aspect of the lighting device according to the present disclosure, the projected image of the fluorescence in the focal region of the second focal point of the reflector is the first intensity distribution region and the first intensity distribution region. It has a second intensity distribution region having a small fluorescence intensity, the first intensity distribution region is included in the second intensity distribution region, and the center of the first intensity distribution region and the second intensity distribution region. It may be aligned with the center of the intensity distribution region of.

With this configuration, alignment between a laser light source that emits a plurality of laser beams, a phosphor, and a reflecting mirror can be realized with high accuracy. Further, such an alignment can be realized by adjusting the center positions of the first intensity distribution region and the second intensity distribution region. That is, since the first intensity distribution region and the second intensity distribution region can be easily confirmed by visual inspection or the like, alignment can be easily realized. Further, by realizing highly accurate alignment, the fluorescence light collection efficiency of the reflecting mirror can be improved.

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

This makes it possible to reduce the size of the laser light source.

Further, in one aspect of the lighting device according to the present disclosure, the optical lens is an aspherical lens, has a function of equalizing the light intensity distribution in a direction in which the spread angle of the plurality of laser beams is large, and has the function of equalizing the light intensity distribution. The body may be placed closer to the optical lens than the focal point of the optical lens.

As a result, the peak intensity of the focused 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 arranging the phosphor closer to the optical lens than the focal point of the optical lens, a plurality of laser beams are applied to the phosphor with a uniform intensity distribution formed by superimposing the intensity distributions of the plurality of laser beams. Can be irradiated.

Further, in one aspect of the lighting device according to the present disclosure, the optical lens has a microlens region in which a plurality of microlenses are formed, and each of the plurality of microlenses has a different focal point, and the phosphor. Is arranged at a position farther from the optical lens than the focal point of each of the plurality of microlenses, and among the plurality of laser beams, a plurality of components each focused by the plurality of microlenses are on the light emitting surface of the phosphor. By overlapping, the light intensity distributions of the plurality of laser beams in the large direction and the small direction may be made uniform on the light emitting surface.

As a result, the peak intensity of the laser beam on the light emitting surface of the phosphor can be further reduced, and the decrease in energy conversion efficiency due to luminance saturation, temperature quenching, and the like can be further suppressed. Further, by installing 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 improved.

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

This makes it possible to minimize the gap between adjacent minute lenses. Therefore, since the region of the gap that does not act as a lens can be minimized, a plurality of laser beams can be used more efficiently as excitation light.

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

As a result, the fluorescence emitted from the phosphor arranged in the focal region of the first focal point can be focused on the second focal point. In addition, since the fluorescence reflected by the reflecting mirror once intersects at the second focal point, the shadow of the support member or the like that supports the phosphor is formed as compared with the case where the fluorescence is emitted as parallel light by the rotating parabolic reflector. It is possible to suppress the formation on the fluorescent 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 by a simple configuration.

FIG. 1 is a cross-sectional view showing 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 the course of fluorescence in the lighting device according to the first embodiment. FIG. 4A is a first schematic cross-sectional view illustrating the details of the fluorescence path in the vicinity of the first focal point and the second focal point of the reflector according to the first embodiment. FIG. 4B is a second schematic cross-sectional view illustrating the details of the first focal point and the fluorescence path in the vicinity of the second focal point of the reflector according to the first embodiment. FIG. 4C is a schematic diagram of a projection image of fluorescence in the xy plane in the focal region of the second focal point of the reflector in the illuminating device according to the first embodiment. 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 view of a yz cross section showing a laser beam path for explaining the operation of the aspherical lens according to the first embodiment. FIG. 7 is a schematic diagram of a zx cross section showing a laser beam path for explaining the operation of the aspherical lens according to the first embodiment. FIG. 8 is a distribution diagram showing a two-dimensional distribution of the focused light intensity in the xy plane at the position where the phosphor according to the first embodiment is arranged. FIG. 9 is a cross-sectional view taken along the line yz showing a schematic configuration of the lighting device according to the second embodiment. FIG. 10A is a plan view showing a schematic configuration of the optical lens according to the second embodiment. FIG. 10B is a first cross-sectional view showing a schematic configuration of the optical lens according to the second embodiment. FIG. 10C is a second cross-sectional view showing a schematic configuration of the optical lens according to the second embodiment. FIG. 11 is a schematic diagram of a zx cross section showing a laser beam path for explaining the 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 of the laser light intensity according to the second embodiment. 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 the second embodiment. FIG. 13 is a schematic view of a yz cross 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 the optical lens of the laser light intensity according to the second embodiment in the y-axis direction. FIG. 14B is a schematic diagram of a one-dimensional profile of the position of the phosphor of the laser light intensity according to the second embodiment in the y-axis direction. FIG. 15 is a graph showing the intensity distribution of convergent light in the phosphor of the lighting device according to the second embodiment. FIG. 16A is a plan view showing a schematic configuration of an optical lens according to a modified example of the second embodiment. FIG. 16B is a first cross-sectional view showing a schematic configuration of an optical lens according to a modified example of the second embodiment. FIG. 16C is a second sectional view showing a schematic configuration of an optical lens according to a modified example of the second embodiment. FIG. 17 is a schematic diagram of a projection image of fluorescence in the xy plane in the vicinity of the second focal point of the reflector of the lighting device according to the modified example of the second embodiment. FIG. 18 is a cross-sectional view showing a schematic configuration of a conventional lighting device.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. It should be noted that all of the embodiments described below show a specific example of the present disclosure. Therefore, the numerical values, shapes, materials, components, the arrangement positions of the components, the connection form, 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, the components not described in the independent claims indicating the highest level concept of the present disclosure are described as arbitrary components.

Further, each figure is a schematic view and is not necessarily exactly shown. Therefore, the scales and the like do not always match in each figure. In each figure, the same reference numerals are given to substantially the same configurations, and duplicate explanations will be omitted or simplified.

(Embodiment 1)
[1-1. Lighting equipment configuration]
The lighting device 100 according to the first embodiment will be described with reference to FIG. FIG. 1 is a cross-sectional view showing a schematic configuration of the lighting device 100 according to the first embodiment. Further, 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 illuminating device 100 parallel to the yz plane.

As shown in FIG. 1, the 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 aspherical lens 50, and a connecting member 60. A reflector 70, a support member 80, a high-reflection substrate 85, and a phosphor 90 are provided.

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 in which the semiconductor laser element 1 is arranged, a stem 10b that supports the submount 2, a base 10a in which the stem 10b is arranged, 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. This makes it possible to realize a miniaturized laser light source.

The peak wavelength of the laser beam emitted from the semiconductor laser device 1 is not particularly limited, but in the present embodiment, it is 390 nm or more and 460 nm or less. Specifically, the semiconductor laser device 1 is an InGaN-based multi-emitter laser diode element 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 highly heat-dissipating metal material having high thermal conductivity such as aluminum and copper. A semiconductor laser light emitting device 19 is fixed to one end of the metal base member 20. The laser beam emitted from the semiconductor laser element 1 travels in the direction opposite to the direction from the semiconductor laser element 1 toward the metal base member 20. In order to improve the heat dissipation of the metal base member 20, a heat sink 30 is provided on the opposite surface of the metal base member 20 from the mounting surface of the semiconductor laser light emitting device 19.

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

The reflector 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 fluorescence emitted from the phosphor 90. do. As an example of such a reflecting mirror 70, there is a reflecting mirror (elliptic reflecting mirror) having a spheroidal reflecting surface, and the reflecting surface 71 of the reflecting mirror 70 is a spheroidal concave surface. Further, the reflecting mirror 70 is provided with an opening 75. Specifically, the opening 75 is a through hole provided at the top of the long axis of the reflecting mirror 70. The opening 75 does not have to be a through hole. For example, the opening 75 may be a notch formed in the reflecting mirror 70.

The reflecting mirror 70 may have a metal thin film formed as a reflecting surface 71 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 reflector 70 are connected by a connecting member 60. A cylindrical cavity is provided inside the connecting member 60, a lens holding member 40 is provided inside the cavity, and the aspherical lens 50 is held by the lens holding member 40. That is, the connecting member 60 also functions as a lens barrel.

The aspherical lens 50 is an example of an optical lens in which a plurality of laser beams emitted from the semiconductor laser element 1 are incident and the incidented laser beams are converted into convergent light. The aspherical lens 50 is made of a translucent material such as quartz, and is arranged on the optical path of a plurality of laser beams of the semiconductor laser element 1. The plurality of laser beams emitted from the semiconductor laser element 1 are focused by the aspherical lens 50. In the present embodiment, the aspherical lens 50 has a function of equalizing the light intensity distribution in the direction in which the spread angle of the plurality of laser beams is large. That is, the aspherical lens 50 not only collects a plurality of incident laser beams, 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 in detail later.

The phosphor 90 is a wavelength conversion element that emits fluorescence when convergent light is irradiated as excitation light. The phosphor 90 is a focal region of the first focal point of the reflecting mirror 70, and is arranged at a position deviated from the focal point of the aspherical lens 50 in the optical axis direction of the focused light. Here, the focal area of the first focal point is an area of the first focal point and its vicinity. 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. 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. As a result, the fluorescence emitted from the phosphor 90 can be accurately focused on the second focal point. The focal area of the second focal point is also defined in the same manner.

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

The fluorescent materials constituting the fluorescent substance 90 are, 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⁺ ) A mixture with a fluorescent material. The blue light emitting SCA emits blue light when excited by a blue-purple laser light having a peak wavelength of 405 nm emitted from the semiconductor laser element 1. The yellow light emitting Ga-YAG is excited by the bluish-purple laser light emitted from the semiconductor laser element 1 to emit yellow light. The combined light of blue light and yellow light looks white to humans. Therefore, when the laser light emitted from the semiconductor laser element 1 irradiates the phosphor 90, white light is emitted from the phosphor 90 as synthetic light in which blue light and yellow light are mixed. That is, white fluorescence can be obtained with the phosphor 90.

The support member 80 is a member that supports the phosphor 90. In the present embodiment, the support member 80 has a rod-like shape having a quadrangular cross section, and one end thereof in the longitudinal direction is fixed to a part of the reflector 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 made of a material having high transparency to visible light in addition to high thermal conductivity, such as GaN, SiC, AlN, or diamond. This makes it possible to reduce absorption or reflection of fluorescence in the support member 80. Therefore, the fluorescence emission efficiency of the lighting device 100 can be improved. Although an example in which one end of the support member 80 in the longitudinal direction is fixed to the reflector is shown in FIG. 1, a phosphor 90 is provided at the center of the support member 80 in the longitudinal direction, and both ends of the support member 80 are mirrors 70. It may be fixed to. In that case, the heat dissipation performance from the phosphor 90 is further improved. In addition, the phosphor 90 can be more firmly fixed to the reflector 70.

[1-2. Operation of lighting equipment]
Next, the operation of the lighting device 100 according to the first embodiment will be described with reference to FIGS. 2 to 8. As in FIG. 1, each figure shows three-dimensional orthogonal coordinate axes of x-axis, y-axis, and z-axis.

2 and 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. 2 and 3 show vertical cross sections of the illuminating device 100 parallel to the yz plane and the zx plane, respectively.

First, the course of the laser beam will be described with reference to FIG. As shown in FIG. 2, the bluish-purple laser light 111 emitted from the semiconductor laser light emitting device 19 is converted from divergent light to focused light 51 by the aspherical lens 50, and then the reflecting mirror 70 is converted from the opening 75 of the reflecting mirror 70. The light is guided into the concave portion of the light emitting surface 91 of the phosphor 90 arranged in the vicinity of the first focal point (focal region) of the reflecting mirror 70. At this time, the heat generated by the reactive power (power obtained by subtracting the optical output from the input power) of the semiconductor laser element 1 is dissipated from the heat sink 30. A part of the focused light 51 irradiated to the phosphor 90 is absorbed by the phosphor 90 and converted into blue and yellow fluorescence. Then, white fluorescence, which is a synthesized light synthesized by mixing blue fluorescence and yellow fluorescence, is obtained.

Next, the course of fluorescence will be described with reference to FIG. The white fluorescence 110 generated by the phosphor 90 is reflected by the reflecting surface 71 of the reflecting mirror 70, reflected by the reflecting surface 71, and then emitted as convergent light to the outside of the reflecting mirror 70, which is a rotating elliptical 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 a spheroidal reflecting surface 71, the fluorescence reflected by the reflecting mirror 70 once intersects at the second focal point as shown in FIG. 3 and the like. Therefore, it is possible to suppress the formation of shadows such as the support member 80 that supports the phosphor 90 on the fluorescence irradiation surface, as compared with the case where fluorescence is emitted as parallel light by a rotating parabolic reflector.

Most of the white fluorescence that reaches the vicinity of the second focal point f2 of the reflector 70 is the fluorescence emitted by the Lambersian light distribution from the phosphor 90 excited by the focused light 51 on the reflecting surface 71 of the reflector 70. It is reflected back. However, by analyzing the projected image of white fluorescence in the vicinity of the second focal point f2 in detail, the inventors have found that there is a fluorescent component that reaches the second focal point f2 by a route different from the above. .. Fluorescence with different pathways will be described with reference to FIGS. 4A-4C.

4A and 4B are first and second schematic cross sections illustrating details of the fluorescence path near the first focal point and the second focal point (focal point region) of the reflector 70 according to the present embodiment, respectively. It is a figure. FIG. 4C is a schematic diagram of a projection image of fluorescence in the xy plane in the focal region of the second focal point of the reflector 70 in the lighting device 100 according to the present embodiment. In FIG. 4A, it is assumed that the fluorescence 110 emitted from the phosphor 90 is reflected once at the point P on the reflecting surface 71 of the reflecting mirror 70. Most of the fluorescent components that have reached the point P are reflected once by the reflecting surface 71 and focused on the second focal point f2 of the reflecting mirror 70. However, since the reflective surface 71 is not a perfect spheroidal surface, a small part of the fluorescence component is scattered by the surface unevenness of the point P, and as shown by the dotted line in FIG. 4A, there is a fluorescence 114 that returns to the phosphor 90 direction. do. Further, since the surface of the phosphor 90 is not a perfect mirror surface, the fluorescence 114 returned to the phosphor 90 is further scattered on the surface or inside of the phosphor 90 to change the traveling direction and move toward the point Q on the reflecting surface 71. It is emitted, reflected at the point Q, and then reaches the second focal point f2 of the reflecting mirror 70 (see fluorescence 115 shown by a dotted line in FIG. 4A). FIG. 4A is an example explaining one locus of the fluorescence 115, but the traveling direction of the fluorescence after being rescattered by the phosphor 90 is omnidirectional (180 degrees) when viewed from the surface of the phosphor 90 as shown in FIG. 4B. ), The emission angle becomes wider than the emission characteristic (Lumbercian) of fluorescence due to laser light excitation. As a result, the projection image of the fluorescence at the position f2n near the second focal point f2 (focal point region) of the reflecting mirror 70 shown in FIG. 4B is scattered once by the reflecting surface 71 of the reflecting mirror 70 as shown in FIG. 4C. The projection image of the fluorescence 110 and the projection image of the multiple-scattered fluorescence 115 are superimposed to form a projection image. The former shows an intensity distribution that directly reflects the intensity distribution of the focused light 51 (that is, the excitation light) on the light emitting surface 91 of the phosphor 90, and in the present embodiment, the region of this intensity distribution is referred to as the first intensity distribution below. It 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, the region of this intensity distribution is hereinafter referred to as the second intensity distribution region 115r. Refer to.

The second intensity distribution region 115r is uniquely determined if the installation direction of the reflecting mirror 70 is determined, but the first intensity distribution region 110r can change depending on the irradiation position of the laser beam on the phosphor 90. For example, if the irradiation position of the focused light 51 on the phosphor 90 deviates from the first focal point of the reflecting mirror 70, the projected image of the fluorescence does not look like FIG. 4C. That is, the center of the first intensity distribution region 110r and the center of the second intensity distribution region 115r are deviated from each other, and the fluorescence light collection efficiency of the reflector 70 is lowered. Conversely, according to this configuration, even if the irradiation position of the focused light 51 on the light emitting surface 91 of the phosphor 90 cannot be directly observed, the projection image of the fluorescence at the position f2n near the second focal point f2 of the reflector 70. By observing, the irradiation position of the focused light 51 can be indirectly observed. This makes it possible to adjust the optical axis extremely easily and with high accuracy. From the above description, 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 fluorescence reflectance of the reflecting surface 71 of the reflecting mirror 70 should be high. For example, the fluorescence reflectance of the reflecting surface 71 may be 80% or more. As a result, the two intensity distribution regions can be clearly distinguished as shown in FIG. 4C. Further, the fluorescence reflectance of the reflecting surface 71 may be 90% or more. This makes it possible to more clearly distinguish between the two intensity distribution regions.

As described above, in the present embodiment, the projection image of the fluorescence in the focal region of the second focal point of the reflector 70 has a smaller fluorescence intensity than the first intensity distribution region 110r and the first intensity distribution region 110r. It has 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 and the center of the second intensity distribution region 115r coincide with each other. Thereby, the alignment between the semiconductor laser element 1, the phosphor 90, and the reflecting mirror 70 that emits a plurality of laser beams 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 inspection or the like, highly accurate alignment can be easily realized. Further, by realizing highly accurate alignment, the fluorescence light collection efficiency of the reflecting mirror 70 can be improved.

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 region. Further, the matching of the centers of the respective intensity distribution regions is not limited to the case where the centers are completely matched, but also includes the case where the centers are substantially matched. 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 reflective surface 71 has a spheroidal shape, the shape of the first intensity distribution region 110r having high intensity is closer to a circle, and the more uniform the intensity distribution, the more circular the shape of the fluorescence irradiation region. It is close and the intensity distribution is uniform.

According to the present embodiment, as shown in FIG. 4C, it is possible to realize the first intensity distribution region 110r that is substantially inscribed in the circle (in other words, the gap between the circumscribed circle is small). The details thereof will be described with reference to FIGS. 5 to 8. Each figure shows three-dimensional orthogonal coordinate axes of x-axis, y-axis and z-axis as in FIGS. 1 to 4C. 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 emitting modes from the semiconductor laser element 1, and is a perspective view illustrating the semiconductor laser light emission shown in FIGS. 1 to 4B. The details of the apparatus 19 are shown. In FIG. 5, the semiconductor laser light emitting device 19 is a packaged light emitting device, and includes a semiconductor laser element 1 having a plurality of light emitting regions in one laminate and a metal cap (can) 12 constituting the package. Be prepared. By using such a semiconductor laser element 1, the semiconductor laser light emitting device 19 can be miniaturized. 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 a cap 12. Specifically, the semiconductor laser element 1 is mounted on the stem 10b arranged on the disk-shaped base 10a via the submount 2. In the present embodiment, the semiconductor laser element 1 is arranged so 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 so that the longitudinal direction (stripe direction) of the optical waveguide 11a is the z-axis direction.

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

The emission angles of the laser beams 111a and 111b from the semiconductor laser element 1 are different in the orthogonal biaxial directions, and the emission angle in the x-axis direction is narrower than the emission angle in the y-axis direction.

That is, the direction of the stripe width and the direction of the narrow radiation angle are the same.

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. As a result, the semiconductor laser device 1 can be further miniaturized.

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

In FIG. 6, the aspherical lens 50 is an optical element that converts the laser beam 111 emitted as divergent light from the semiconductor laser element 1 into convergent light. Since the laser beam 111a from the optical waveguide 11a and the laser beam 111b from the optical waveguide 11b of the semiconductor laser element 1 are substantially the same in terms of the yz cross section, the two laser beams are not distinguished from each other and are referred to as the laser beam 111. Refer to. The aspherical lens 50 has an inner and outer peripheral difference in refractive force, and the convergent light from the aspherical lens 50 is focused on the focal plane fy1 by the near-axis ray 51c (dotted line shown in FIG. 6) of the aspherical lens 50 and is not. The light ray 51e (one-point chain line shown in FIG. 6) passing through the outer peripheral portion of the spherical lens 50 is focused on the position fy2 deviated from the focal plane fy1. The difference in the focal position between the inner peripheral side and the outer peripheral side of the aspherical lens 50 is called spherical aberration. Spherical aberration is generated by increasing the refractive power from the central portion of the aspherical lens 50 toward the peripheral direction. Since it is necessary to eliminate this as much as possible in order to narrow the beam spot on the focal plane as small as possible, in aspherical lenses on the market in general, the aspherical surface of the aspherical lens so that this spherical aberration becomes infinitely zero. The 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 to the front and back of the focal plane of the paraxial ray.

When the aspherical lens 50 having spherical aberration, that is, the aspherical lens 50 whose refractive force increases toward the outer peripheral direction is used to focus the laser beam of the Gaussian intensity distribution, the light rays 51e on the outer peripheral side with weak intensity gather inside. Due to the effect of overlapping with the aspherical ray 51c, there is a surface on the front side of the focal plane where the light intensity distribution becomes uniform. The position of the surface where the light intensity distribution becomes uniform is adjusted to an arbitrary position between the focal plane fy1 of the near-axis ray and the aspherical lens 50 by changing the amount of spherical aberration of the aspherical lens 50. Can be done. The amount of spherical aberration of the aspherical 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 aspherical lens 50. In the present embodiment, the phosphor 90 is installed at a position on the z-axis where the intensity distribution of the laser beam becomes 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 aspherical lens 50 has a function of equalizing the light intensity distribution in the direction in which the spreading angle of the two laser beams from the semiconductor laser element 1 is large (that is, in the Y-axis direction), and the phosphor 90 has a function of equalizing the light intensity distribution. It is arranged closer to the aspherical lens 50 than the focal point of the aspherical lens 50. As a result, the peak intensity of the focused light on the light emitting surface 91 of the phosphor 90 can be reduced, and the decrease in energy conversion efficiency due to luminance saturation, temperature quenching, and the like can be suppressed. Further, by arranging the phosphor 90 closer to the aspherical lens 50 than the focal point of the aspherical lens 50, the uniform intensity formed by superimposing the intensity distributions of the two laser beams from the semiconductor laser element 1 is formed. With the distribution, the phosphor 90 can be irradiated with laser light (convergent light).

In the schematic view of the zx cross section of FIG. 7, the emission side end surface of the laser light of the semiconductor laser element 1 is parallel to the main plane of the aspherical lens 50, and the first light emitting region (optical waveguide 11a in FIG. 5) and the second The light emitting region (optical waveguide 11b in FIG. 5) is equidistant from the aspherical lens 50. The laser beam 111a (two-point chain line) from the first light emitting region of the semiconductor laser element 1 and the laser light 111b (dotted line) from the second light emitting region are incident on the aspherical lens 50 in a state of being substantially overlapped with each other. The laser beams 111a and 111b incident on the aspherical lens 50 are converted into convergent lights 51a and 51b, respectively, and are irradiated on the phosphor 90 in an overlapping state. As described above, by using the two laser beams from the semiconductor laser device 1, the degree of freedom in adjusting the intensity distribution of the focused light in the phosphor 90 can be increased.

In the absence of the phosphor 90, the focused lights 51a and 51b are focused in a state of being completely separated by the focal plane fx after passing through the position. 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 beams 111 in the y-axis direction shown in FIG. 6, the phosphor 90 is not on the light emitting surface 91. The effect of uniformizing the intensities of the focused 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 focused 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 of the focused light intensity in the xy plane at the position where the phosphor 90 according to the present embodiment is arranged. In FIG. 8, graph (a) is a diagram of a beam profile in an xy plane showing the shape of convergent light and its intensity distribution on 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 higher the light intensity. Further, in FIG. 8, the graph (b) is a diagram showing the light intensity (integral value) distribution in the horizontal direction (x-axis direction), and the graph (c) is the light intensity (y-axis direction) in the vertical direction (y-axis direction). It is a figure which shows the distribution (integral value). Further, the graphs (b) and (c) show the intensity distribution of light at the positions of the AA line and the BB line in the graph (a). As shown in FIG. 8, at the position where the phosphor 90 is arranged, the focused light has a uniform light intensity distribution in the shape of the top hat in both the horizontal direction and the vertical direction. 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 the uniform intensity distribution. Because it becomes. That is, the aspherical lens 50 has a function of making the light intensity uniform in the direction having a large spread angle 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 a light intensity distribution can be obtained. That is, the phosphor 90 is arranged at a position shifted to the aspherical lens 50 side from the focal plane where the paraxial light rays of the light passing through the aspherical lens 50 form an image.

In addition to adjusting the position of the phosphor 90, as an adjustment method for obtaining a uniform light intensity distribution, 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 is performed. There is. Specifically, by adjusting the position of the semiconductor laser device 1 in the z-axis direction or adjusting the position of the aspherical lens 50 in the z-axis direction, the positions of the focal planes fx of the two focused lights 51a and 51b can be adjusted. Change. As a result, the degree of overlap of the two focused lights 51a and 51b may be changed, and adjustment may be made so that a uniform light intensity distribution as shown in FIG. 8 can be obtained at the position where the phosphor 90 is installed.

Further, the aspherical 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 becomes uniform at the installation position of the phosphor 90. In the aspherical lens 50, spherical aberration is optimized according to the vertical spread angle of the laser beam emitted from the semiconductor laser element 1.

Further, the above-mentioned uniform intensity distribution 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 deviated from the focal point of the aspherical lens 50, the light density of the focused light in the phosphor 90 can be suppressed. Therefore, it is possible to prevent the energy conversion efficiency of the phosphor 90 from decreasing due to luminance saturation. Further, by using the two laser beams from the semiconductor laser element 1, the degree of freedom in adjusting the intensity distribution of the focused light in the phosphor 90 can be increased. Therefore, by forming an intensity distribution suitable for the shape of the reflecting mirror 70, it is possible to improve the illuminance uniformity of the illumination light emitted from the illumination device 100. Further, the above effects can be realized without complicating the configuration of the lighting device 100.

[1-3. summary]
As described above, in the lighting device 100 of the present embodiment, the semiconductor laser element 1 that emits a plurality of laser beams and the aspherical lens 50 that is incident with the plurality of laser beams and converts the incident laser beams into convergent light. A phosphor 90 that emits fluorescence when the focused light is irradiated as excitation light, and a reflector 70 that has a first focal point and a second focal point and reflects fluorescence. The phosphor 90 is a focal region of the first focal point of the reflecting mirror 70, and is arranged at a position deviated from the focal point of the aspherical lens 50 in the optical axis direction of the focused light.

By arranging the phosphor 90 at a position deviated from the focal point of the aspherical lens 50 in this way, the light density in the phosphor 90 can be suppressed. Therefore, it is possible to prevent the energy conversion efficiency of the phosphor 90 from decreasing due to luminance saturation. Further, by using a plurality of laser beams, it is possible to increase the degree of freedom in adjusting the intensity distribution of the focused light (excitation light) in the phosphor 90. Therefore, by forming an intensity distribution suitable for the shape of the reflecting mirror 70, it is possible to improve the illuminance uniformity of the illumination light emitted from the illumination device 100. Further, the above effect can be realized without complicating the configuration of the lighting device as compared with the prior art disclosed in, for example, Patent Document 1.

Further, in the lighting device 100, the projection image of the fluorescence in the focal region of the second focal point of the reflector 70 is the first intensity distribution region 110r and the second intensity distribution region 110r whose fluorescence intensity is smaller than that of the first intensity distribution region 110r. It has 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 element 1, the phosphor 90, and the reflecting mirror 70 that emit a plurality of laser beams 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 inspection or the like, highly accurate alignment can be easily realized. Further, by realizing highly accurate alignment, the fluorescence light collection efficiency of the reflecting mirror 70 can be improved.

Further, the aspherical lens 50 may be beam-shaped so 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 from the focal plane of the paraxial ray of the aspherical lens 50 to a position closer to the aspherical lens 50.

Since the phosphor 90 is uniformly excited by the convergent light in this way, 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 in adjusting the intensity distribution of the focused 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 focused light can be made closer to the circular shape. Therefore, it has a good affinity with the reflecting surface 71 having a spheroidal shape, and high illuminance uniformity can be obtained in the fluorescence irradiation region.

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

This makes it possible to reduce the size of the laser light source.

Further, in the lighting device 100, the aspherical lens 50 has a function of equalizing the light intensity distribution in the direction in which the spread angle of the plurality of laser beams is large, and the phosphor 90 is aspherical from the focal point of the aspherical lens 50. It may be arranged at a position close to the lens 50.

In this way, by making the light intensity distribution uniform in the direction in which the spread angle of the plurality of laser light is large, the peak intensity of the laser light on the light emitting surface 91 of the phosphor 90 can be reduced, and the brightness saturation and temperature quenching can be achieved. It is possible to suppress a decrease in energy conversion efficiency due to such factors. Further, by arranging the phosphor 90 closer to the aspherical lens 50 than the focal point of the aspherical lens 50, the phosphor 90 has a uniform intensity distribution formed by superimposing the intensity distributions of a plurality of laser beams. Can be irradiated with a plurality of laser beams.

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

As a result, the fluorescence 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 fluorescence reflected by the reflector 70 once intersects at the second focal point, the support member 80 that supports the phosphor 90 and the like are more than the case where the fluorescence is emitted as parallel light by the rotating parabolic reflector. It is possible to suppress the formation of shadows on the fluorescent irradiation surface.

(Embodiment 2)
[2-1. Lighting equipment configuration]
Next, the lighting device 200 according to the second embodiment will be described with reference to FIGS. 9 to 15. Each figure shows three-dimensional orthogonal coordinate axes of x-axis, y-axis and z-axis as in FIGS. 1 to 8. FIG. 9 is a cross-sectional view taken along the line yz showing a schematic configuration of the lighting device 200 according to the second embodiment. The same members as those of the lighting device 100 of the first embodiment are designated by the same number, and the description thereof will be omitted here. The only difference in the configuration of the illuminating device 200 in FIG. 9 and the illuminating device 100 in the first embodiment is the configuration of an optical member for beam-shaping the laser beam and irradiating the phosphor 90 on the phosphor 90, and the illuminating device 200 has a plurality of configurations. An optical lens 55 having a microlens region in which the microlens of the above is formed is used.

[2-2. Operation of lighting equipment]
Next, the operation of the lighting device 200 according to the second embodiment will be described with reference to FIGS. 10A to 15. Also in this embodiment, the operation of exciting the phosphor 90 with a laser beam to generate white fluorescence 110 and 115 and projecting the white fluorescence in a desired direction by the reflecting mirror 70 is shown in FIGS. 3, 4A and FIGS. It is the same as the first embodiment shown in 4B. Here, how the laser beam from the semiconductor laser light emitting device 19 is beam-shaped and irradiated with uniform intensity on the light emitting surface 91 of the phosphor 90 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 showing a schematic configuration of the optical lens 55 according to the second embodiment, respectively. 10A is a plan view of the optical lens 55 in the optical axis direction view (z-axis direction view) of a plurality of laser beams emitted from the semiconductor laser light emitting device 19, and FIG. 10B is a cross section of 10B-10B of FIG. 10A. It is a schematic diagram, and FIG. 10C is a schematic view of a cross section of 10C-10C of FIG. 10A.

As shown in FIG. 10A, the optical lens 55 has a microlens region 55R in which a plurality of microlenses 55a, 55b, 55c, 55d, 55e, 55f, 55g, 55h and 55i are formed. The plurality of hexagons in the microlens region 55R shown in FIG. 10A all indicate microlenses, and only a part thereof is designated by a reference numeral.

In the optical lens 55 according to the present embodiment shown in FIG. 10A, each of the plurality of microlenses has a different focal point. That is, each minute lens is formed so that the focusing position of the laser light converted into the focused light by the plurality of minute lenses of the optical lens 55 is different from each other. In the present embodiment, the focusing position of the laser beam 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 in the optical axis direction view (that is, the z-axis direction view of FIG. 10A) of the plurality of laser beams is a hexagonal shape. This makes it possible to minimize the gap between adjacent minute lenses. Therefore, since the region of the gap that does not act as a lens can be minimized, a plurality of laser beams can be used more efficiently as excitation light.

The hexagonal short axis width W1 and the long axis width W2 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, it is installed by the 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 of the laser light 111a or 111b in FIG. / Horizontal width = W2 / W1. Further, as shown in FIGS. 10B and 10C, the microlens region 55R has an uneven shape having a sawtooth cross section, and each of the convex portions forms a microlens. 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 semiconductor laser light emitting device 19 side.

Subsequently, the beam shaping function in the x-axis direction of the lighting 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 cross-sectional view (a) of FIG. 11, the end surface of the laser beam of the semiconductor laser element 1 on the emission side is parallel to the main plane of the optical lens 55 having a plurality of minute lenses, and is the first light emitting region (optical waveguide 11a of FIG. 5). ) And the second light emitting region (optical waveguide 11b in FIG. 5) are at equal distances from the microlens 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 element 1 are incident on the microlens 55a in a state of substantially overlapping. The laser beams 111a and 111b incident on the microlens 55a are converted into convergent lights 51aa and 51ba, respectively, once focused at the focal points 52aaf and 52baf, then diverged again and incident on the phosphor 90, and the region x1 And x2 are excited. The shape of the microlens 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 focused light 51ac and 51bc emitted from the microlens 55c are focused at the positions of the focal points 52acf and 52bcf, respectively, and then diverge again to enter the phosphor 90. , Exciting regions x1 and x2.

Similarly, in the cross-sectional view (c) of FIG. 11, the focused light 51ae and 51be emitted from the microlens 55e are focused at the positions of the focal points 52aef and 52be, respectively, and then diverge again and enter the phosphor 90. , Exciting regions x1 and x2. Although not particularly shown, similarly, in the minute lenses 55b and 55d, the respective focused lights are incident on 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 the lens is located closer to the phosphor 90. The alternate long and short dash line shown in the cross-sectional views (a) to (c) of FIG. 11 indicates the positions of the focal points 52aaf and 52baf in the z-axis direction. Further, the focal points 52aef and 52bef of the microlens 55e (see the cross-sectional view (c) of FIG. 11) are closer to the phosphor 90 than the focal points 52acf and 52bcf of the microlens 55c (see the cross-sectional view (b) of FIG. 11). You can see that it is located. As described above, the plurality of microlenses each have a different focal point, the phosphor 90 is located farther from the optical lens 55 than these focal points, and each laser passing through the focal point in each of the plurality of microlenses. The light overlaps on the light emitting surface of the phosphor 90.

Subsequently, the intensity distribution of the focused light generated by the optical lens 55 in the x-axis direction will be described with reference to FIGS. 12A and 12B. 12A and 12B are schematic one-dimensional profiles in the x-axis direction at the positions of the optical lens 55 and the phosphor 90 of the laser light intensity according to the present embodiment, respectively. Using FIGS. 12A and 12B, the light intensity distribution when the laser beam 111a emitted from one of the optical waveguides 11a of the semiconductor laser device 1 is divided by each minute lens and the divided laser beam 111a become convergent light. The intensity distribution when the light is converted and focused on the region 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 focused light from each minute lens on the light emitting surface 91 of the phosphor 90. (X-axis direction) is shown. The laser beam 111a is divided into convergent lights 51aa, 51ab, 51ac, 51ad and 51ae by five microlenses as shown in FIG. 12A, and overlaps again in the region x1 of the phosphor 90 as shown in FIG. 12B. The sum of the convergent lights in FIG. 12B has a profile with a uniform intensity distribution as shown by the solid line. As shown in FIG. 12B, for example, the convergent light 51ad having an intensity distribution inclined upward to the right shoulder and the focused light 51ae having an intensity distribution inclined downward to the right shoulder overlap in the region x1. As a result, at least a part of the gradient of the intensity distribution is offset and becomes uniform. Similarly, the gradient of the intensity distribution is canceled out by overlapping the convergent light 51ab having the inclined intensity distribution and the convergent light 51ac in the region x1. In this way, it is possible to obtain convergent light having a substantially uniform intensity distribution in the region x1. Although not particularly shown, similarly, the laser beam 111b from the other optical waveguide 11b is also shaped into a uniform profile of the intensity distribution as shown in FIG. 12B in the region x2 of the phosphor 90.

Subsequently, the beam shaping function in the y-axis direction of the lighting device 200 will be described with reference to FIG. FIG. 13 is a schematic view of a yz cross 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 beams incident on the microlenses 55a, 55f and 55h, respectively.

In the cross-sectional view (a) of FIG. 13, the end surface of the laser beam of the semiconductor laser element 1 on the emission side is parallel to the main plane of the optical lens 55 having a plurality of minute lenses, and is the first light emitting region (optical waveguide 11a of FIG. 5). ) And the second light emitting region (optical waveguide 11b in FIG. 5) are at equal distances from the microlens 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 element 1 are substantially the same in terms of the yz cross section, the two laser lights are not distinguished from each other and are referred to as the laser light 111. Refer to. In the cross-sectional view (a) of FIG. 13, the component incident on the minute lens 55a of the laser beam 111 is converted into the focused light 51ay, once focused at the position of the focal point 52ayf, and then diverged again to the phosphor 90. It enters and excites the region y1.

Similarly, in the cross-sectional view (b) of FIG. 13, the focused light 51fy emitted from the microlens 55f is focused at the position of the focal point 52fyf, then diverges again and is incident on the phosphor 90 to excite the region y1. do.

Similarly, in the cross-sectional view (c) of FIG. 13, the focused light 51hy emitted from the minute lens 55h is focused at the position of the focal point 52hyf, then diverges again and is incident on the phosphor 90 to excite the region y1. do. Although not particularly shown, similarly, in the minute lenses 55g and 55i, the respective focused lights are incident on 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. .. Further, it can be seen that the focal point 52hyf of the microlens 55h is located closer to the phosphor 90 than the focal point 52fyf of the microlens 55f. As described above, the plurality of microlenses each have a different focal point, the phosphor 90 is arranged closer to the phosphor 90 than these focal points, and each laser beam passing through the focal point in each of the microlenses is , The light emitting surfaces of the phosphor 90 overlap. The individual microlenses are designed so as not to have astigmatism. For example, the focal points 52aaf and 52baf of the microlenses 55a in the x-axis direction (see the cross-sectional view (a) of FIG. 11) and the focal point in the y-axis direction. The positions on the z-axis of 52ayf (see the cross-sectional view (a) of FIG. 13) are the same. As a result, by installing the aperture 75 of the reflecting mirror 70 near the focal point of each minute lens, 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 focused 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 according to the present embodiment in the y-axis direction, respectively. Using FIGS. 14A and 14B, the light intensity distribution when the laser light 111 emitted from the optical waveguides 11a and 11b of the semiconductor laser element 1 is divided by each minute lens, and the divided laser light 111 become convergent light. The light intensity distribution when the light is converted and focused on the region 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 focused light from each microlens in the region y1 of the phosphor 90 (the y-axis direction). (Y-axis direction) is shown. The laser beam 111 is divided into convergent lights 51ay, 51fy, 51gy, 51hy and 51yy as shown in FIG. 14A by five microlenses, and overlaps again in the region y1 of the phosphor 90 as shown in FIG. 14B. As a result, similar 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.

An example of the intensity distribution of the focused 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 the phosphor 90 of the lighting device 200 according to the second embodiment. In the graphs (a) and (d) of FIG. 15, the laser light from the optical waveguide 11a (the laser light 111a shown in FIG. 11 and the laser light 111 shown in FIG. 13) are optical lenses 55 having a plurality of minute lenses, respectively. It is a two-dimensional intensity distribution display and a three-dimensional intensity distribution display of the light intensity distribution on the light emitting surface 91 of the convergent light converted in. In the graphs (b) and (e) of FIG. 15, the laser light from the optical waveguide 11b (the laser light 111b shown in FIG. 11 and the laser light 111 shown in FIG. 13) are optical lenses 55 having a plurality of minute lenses, respectively. It is a two-dimensional intensity distribution display and a three-dimensional intensity distribution display of the light intensity distribution on the light emitting surface 91 of the excitation light converted in. The graphs (c) and (f) of FIG. 15 are optical lenses having a minute lens of the laser light of the optical waveguides 11a and 11b (laser light 111a and 111b shown in FIG. 11 and laser light 111 shown in FIG. 13, respectively). It is a two-dimensional intensity distribution display and a three-dimensional intensity distribution display of the light intensity distribution on the light emitting surface 91 of the excitation light converted in 55. Both are views viewed from the optical lens 55 side, and are shown by the two-dimensional intensity distribution display and the three-dimensional intensity distribution display of the light intensity distribution. In the two-dimensional intensity distribution display of the graphs (a) to (c), the light intensity distribution is shown in inverted gray scale.

As shown in the graphs (a) and (d) of FIG. 15, and as shown in (b) and (e), the fluorescence of the focused 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 uniformized. Further, as shown in the graphs (c) and (f) of FIG. 15, each convergent light is designed so as to partially overlap with the light emitting surface 91 of the phosphor 90, and is one uniform as a whole. It has a light intensity distribution.

As described above, one light intensity distribution can be obtained by the optical lens 55 having a plurality of minute lenses. Further, the light intensity distribution can be adjusted by appropriately designing the shape of each minute lens. As a result, it is possible to form a light intensity distribution suitable for the reflecting mirror 70, so that it is possible to realize an illuminating device 200 capable of emitting highly uniform illumination light.

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

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

Further, 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 view (that is, the z-axis direction view) of the laser beam may be a hexagonal shape.

This makes it possible to minimize the gap between adjacent minute lenses. Therefore, since the region of the gap that does not act as a lens can be minimized, the two laser beams from the semiconductor laser element 1 can be used more efficiently as the excitation light.

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

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

(Modified Example of Embodiment 2)
Next, a modified example of the lighting device 200 according to the second embodiment will be described with reference to the drawings.

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

As shown in FIG. 16A, the optical lens 155 according to the present modification has a microlens region 155R in which a plurality of microlenses 155a, 155b, 155c, 155d, 155e, 155f, 155g, 155h and 155i are formed. In this modification, the plurality of quadrangles in the microlens region 155R shown in FIG. 16A all indicate microlenses, and only a part thereof is designated.

As shown in FIG. 16A, the shape of at least a part of the plurality of microlenses 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 minute lenses in the optical axis direction (that is, the z-axis direction in FIG. 16A) is a quadrangular shape. This makes it possible to minimize the gap between adjacent minute lenses. Therefore, since the region of the gap that does not act as a lens can be minimized, a plurality of laser beams can be used more efficiently as excitation light. The rectangular short-axis width W1 and long-axis width W2 shown in FIG. 16A 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, it is installed by the 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 of the laser light 111a or 111b in FIG. / Horizontal width = W2 / W1. Further, as shown in FIGS. 16B and 16C, the microlens region 155R has an uneven shape having a sawtooth cross section, and each of the convex 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 equipment]
In this modification, the description is omitted where the operation of the device is the same as the operation of the lighting device 200 of the second embodiment as well as the configuration. In the second embodiment, the two-dimensional intensity distribution of the focused light on the light emitting surface of the phosphor 90 on the xy plane is hexagonal, but in this modification, it is rectangular. 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 this modification will be described with reference to FIG. FIG. 17 is a schematic diagram of a projection image of fluorescence in the xy plane in the vicinity of the second focal point (focal region) of the reflecting mirror 70 of the lighting device according to the present modification. As shown in FIG. 17, in this modification, the first intensity distribution region 110r also has a rectangular shape similar to the shape of the microlens. Also in this case, by making the shape of the first intensity distribution region 110r closer to, for example, a square, the affinity with the reflecting surface 71, which is a spheroidal surface, can be enhanced. As a result, high illuminance uniformity can be obtained in the fluorescence irradiation region of the lighting device according to the present modification.

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

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

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

For example, in the above embodiment, the lighting device is configured to emit white light by a blue phosphor and a yellow phosphor, but the present invention is not limited to this. For example, a blue phosphor, a red phosphor, and a green phosphor may be used to emit white light, or a combination of other phosphors may be used to emit white light. 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 row or may be arranged in any other manner. 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, a configuration is adopted in which the intensity of the focused light is made uniform at a position closer to the aspherical lens 50 than the focal point of the aspherical 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 focused light can be made uniform at a position far from the aspherical lens 50 than the focal point of the aspherical lens 50. It is possible.

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

For example, a form obtained by applying various modifications to each embodiment and modification that a person skilled in the art can think of, and components and functions in each embodiment and modification are arbitrarily provided without departing from the spirit of the present disclosure. The forms realized by the combination are also included in the present disclosure.

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

1 Semiconductor laser element (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 near-axis ray 51e ray 52aaf, 52acf, 52aef, 52ayf, 52baf , 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 Microlens 55R , 155R Micro lens area 60 Connecting member 70, 1114, 1208 Reflector 71 Reflection surface 75 Opening 80 Support member 85 High reflection substrate 90, 1112 Phosphorus 91 Light emitting surface 100, 200 Illumination device 110, 114, 115 Fluorescent 110r 1st 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 Board 1110 Lens 1116 Light transmission part 1204 Transmission member 1206 Housing

Claims (5)

A laser light source that emits multiple laser beams and
An optical lens in which the plurality of laser beams are incident and the incidented laser beams are converted into convergent light.
A phosphor that emits fluorescence when the focused light is irradiated as excitation light, and
It has a first focal point and a second focal point, and is equipped with a reflecting mirror that reflects the fluorescence.
The phosphor is arranged in the focal region of the first focal point of the reflecting mirror at a position deviated from the focal point of the optical lens in the optical axis direction of the focused light .
The optical lens has a microlens region in which a plurality of microlenses are formed.
Each of the plurality of microlenses has a different focus and
The phosphor is arranged at a position farther from the optical lens than the focal point of each of the plurality of microlenses.
Of the plurality of laser beams, a plurality of components focused by the plurality of minute lenses are overlapped on the light emitting surface of the phosphor, so that the direction in which the spread angle of the plurality of laser lights is large on the light emitting surface and Each light intensity distribution in the small direction is made uniform
Lighting equipment. The projection image of the fluorescence in the focal region of the second focal point of the reflector has a first intensity distribution region and a second intensity distribution region in which the fluorescence intensity is smaller than that of the first intensity distribution region. Have and
The first aspect of claim 1, wherein the first intensity distribution region is included in the second intensity distribution region, and the center of the first intensity distribution region and the center of the second intensity distribution region coincide with each other. Lighting device. The lighting device according to claim 1 or 2, wherein the laser light source is a semiconductor laser element having a plurality of light emitting regions in one laminated body. The lighting device according to any one of claims 1 to 3 , wherein the shape of at least a part of the plurality of microlenses in the optical axis direction of the plurality of laser beams is a quadrangular shape or a hexagonal shape. The illuminating device according to any one of claims 1 to 4 , wherein the reflecting mirror has a spheroidal reflecting surface.

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