JP6549026B2 - Light emitting device and lighting device - Google Patents

Description

  The present invention relates to a light emitting device that emits laser light from a semiconductor laser element to a phosphor and generates fluorescence from the phosphor, and a lighting device that uses fluorescence generated from the light emitting device as illumination light.

  Lighting devices using semiconductor laser elements include spot lighting, headlights for vehicles, projectors, endoscope lighting, etc., all of which have a wavelength corresponding to the phosphor represented by yttrium aluminum garnet (YAG). The laser light of around 400 nm or around 450 nm is collected and irradiated, and the fluorescence generated by exciting the phosphor or the emitted light composed of the fluorescence and the scattered component of the excitation light is used as the illumination light source. The illumination light source using the semiconductor laser device can reduce the size of the light emitting point as compared to the illumination using a light emitting diode (LED), so the luminance of the illumination device becomes high. As a result, since illumination light with high parallelism can be obtained by the projection optical system, it is possible to irradiate the far side without blurring the beam, and it is possible to miniaturize the optical system for irradiating the radiation forward. It becomes.

  Conventionally, as an example of a lighting device in which a phosphor is combined with this semiconductor laser element, in Patent Document 1, a phosphor lens is irradiated as excitation light with laser light emitted from the semiconductor laser element using a single condensing lens. There has been proposed an illumination device which generates fluorescence from a phosphor and irradiates the fluorescence forward through a reflection surface.

JP 2005-150041 A

  However, in the above-described conventional illumination device, when the high-power laser light is narrowed to a small size on the phosphor for the purpose of creating high-intensity and high-power illumination light, the light density becomes too high and excited electrons are generated. Due to the depletion, so-called luminance saturation occurs, which saturates the conversion efficiency in the phosphor. In addition, temperature quenching of the phosphor may occur as the temperature rises. Furthermore, if the temperature rises above the heat resistant temperature of the phosphor, the phosphor itself is burned and degraded.

  The present invention has been made in view of the above problems, and a light emitting device in which the intensity of a laser beam irradiated to a phosphor is suppressed from being partially increased, and the luminance saturation, temperature quenching, and deterioration of the phosphor are prevented. It is an object of the present invention to provide a lighting device using fluorescence generated from the light emitting device as lighting light.

  A light emitting device according to an aspect of the present invention is configured to receive a plurality of laser light sources emitting a plurality of laser lights and a plurality of laser lights emitted from the laser light sources and convert the plurality of incident laser lights into convergent light An aspheric lens and a fluorescent material that emits fluorescence light by emitting convergent light from the aspheric lens as excitation light, and the plurality of laser beams have different spread angles in the horizontal direction and the vertical direction, and have a small spread angle The light is incident on the aspheric lens in a state of being aligned, and the aspheric lens has a function of making light intensity uniform in the direction in which the spread angle is large.

  In the light emitting device having such a configuration, in the convergent light traveling from the aspheric lens to the phosphor, the light intensity in the direction in which the divergence angle of the laser beam is large is made uniform by the function of the aspheric lens, and the divergence angle of the laser beam is small The light intensity in the direction is made uniform by the overlapping of a plurality of laser beams. For this reason, it is possible to irradiate the phosphor with light whose light intensity has been made uniform in both the horizontal direction and the vertical direction.

  In the light emitting device according to one aspect of the present invention, it is preferable that the paraxial ray of light passing through the aspheric lens of the phosphor be disposed at a position closer to the aspheric lens side than the focal plane forming the image.

  In this case, the phosphor can be disposed at a position where the light intensity in both the flat direction and the vertical direction is most uniformed.

  In the light-emitting device according to one embodiment of the present invention, light-emitting regions of a plurality of laser beams are preferably aligned in the direction in which the spread angle is small.

  In this case, it is possible to adjust the alignment direction and the interval of the laser beams incident on the aspheric lens by the position of the light emitting region of the laser element.

  In the light emitting device according to one aspect of the present invention, the laser light source preferably includes a semiconductor laser element having a plurality of light emitting regions in one element structure.

  In this case, by using a semiconductor laser device in which a plurality of light emitting regions can be periodically arranged at small intervals and the distance between the light emitting regions is optimized, the overlapping state of a plurality of laser beams incident on the aspheric lens Can be optimized.

  A lighting device according to an aspect of the present invention includes the light emitting device of the present invention described above and an optical member that emits fluorescence generated from the light emitting device in a predetermined direction.

  In the illumination device having such a configuration, it is possible to emit the fluorescence generated by irradiating the light whose intensity is uniformed in both the horizontal direction and the vertical direction to the outside as illumination light.

  According to the present invention, light in which light intensity is made uniform in both the horizontal direction and vertical direction is irradiated to the phosphor as excitation light to prevent the luminance saturation, temperature quenching and deterioration of the phosphor, and a light emitting device thereof It is possible to provide a lighting device using fluorescence generated from the light emitting device as lighting light.

FIG. 1 is a vertical sectional view showing a schematic configuration of a light emitting device according to Embodiment 1 of the present invention. FIG. 1 is a horizontal cross-sectional view showing a schematic configuration of a light emitting device according to Embodiment 1. FIG. 2 is a perspective view showing a schematic configuration and a current path of a semiconductor laser device used in the light emitting device according to Embodiment 1. FIG. 2 is a view showing a radiation shape of laser light emitted from a semiconductor laser device in Embodiment 1. Measurement result of intensity distribution of light in horizontal direction and vertical direction on a surface where a single laser beam is made incident to the aspheric lens used in Embodiment 1 and the intensity distribution of convergent light from the aspheric lens becomes uniform FIG. FIG. 7 is a diagram showing an intensity distribution at an arbitrary A-A position between a phosphor and a focal plane in Embodiment 1. FIG. 6 is a view showing an intensity distribution at a B-B position where a phosphor is disposed in Embodiment 1. FIG. 5 is a view showing an intensity distribution at a C-C position between an aspheric lens and a phosphor in Embodiment 1. FIG. 5 is a view showing a wavelength distribution of light emitted from the phosphor to the outside in Embodiment 1. It is sectional drawing which shows schematic structure of the illuminating device which concerns on Embodiment 2 of this invention.

  Hereinafter, embodiments of the present invention will be described in detail. The embodiments described below each show one specific example of the present invention. Numerical values, shapes, materials, components, arrangement positions and connection forms of components, steps, order of steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. In addition, among the components in the following embodiments, components not described in the independent claim showing the highest concept of the present invention are described as optional components.

(Embodiment 1)
FIG. 1 is a vertical sectional view showing a schematic configuration of a light emitting device according to Embodiment 1 of the present invention, and FIG. 2 is a horizontal sectional view showing a schematic configuration of a light emitting device according to Embodiment 1 of the present invention. 1 and 2 show three-dimensional orthogonal coordinate axes of x-axis, y-axis and z-axis, the vertical cross section of FIG. 1 is a cross section of yz plane, and the horizontal cross section of FIG. 2 is xz It is a cross section of the surface.

  The light emitting device of Embodiment 1 includes a laser light source 100, an aspheric lens 120, and a phosphor 130, as shown in FIGS.

  The laser light source 100 is a light source for emitting a plurality of laser beams, and includes a semiconductor laser element 101, a stem 102, an electrode pin 103, a submount 104, a protective cap 105, and a window 106. , The protective cap 105, and the window 106 constitute one package. The semiconductor laser device 101 is accommodated in the package. Specifically, the submount 104 is attached to the inner surface of the stem 102, and the semiconductor laser device 101 is fixed on the submount 104. The semiconductor laser device 101 is disposed in a direction in which laser light is emitted from the window portion 106 to the outside of the package. An electrode pin 103 for supplying power to the semiconductor laser element 101 is exposed to the outside from the stem 102.

  The laser light source 100 is fitted in and fixed to a hole of one surface of the cylindrical housing 140, and the electrode pin 103 protrudes from the surface of the housing 140 to the outside. Laser light is emitted from the semiconductor laser element 101 into the housing 140. The aspheric lens 120 is fixed to the inner surface of the housing 140 via the lens holder 121. Laser light from the semiconductor laser element 101 is incident on the aspheric lens 120. The aspheric lens 120 receives a plurality of laser beams emitted from the laser light source 100 and converts the plurality of incident laser beams into convergent light.

  The phosphor 130 is formed on the transparent substrate 131 in a stacked manner. On the other side of the housing 140, a fixing member 132 having an opening is attached. The other side of the housing 140 is open, and the opening of the fixing member 132 is located in the opening. The transparent substrate 131 is fixed to the fixing member 132 so as to close the opening, and the position of the opening And the phosphor 130 is present. The laser beam that has passed through the aspheric lens 120 enters the phosphor 130. The fluorescent material 130 is irradiated with convergent light from the aspheric lens 120 as excitation light to generate fluorescence. The transparent substrate 131 is in direct contact with a fixing member 132 made of a material having high thermal conductivity or fixed via a heat dissipating grease in order to dissipate the heat generated by the irradiation of the laser light to the phosphor 130.

  FIG. 3 is a perspective view showing a schematic configuration and a current path of the semiconductor laser device 101 used in the light emitting device of Embodiment 1, and FIG. 4 is a view showing a radiation shape of laser light emitted from the semiconductor laser device 101. 3 and 4 also show three-dimensional orthogonal coordinate axes of the x-axis, y-axis, and z-axis, which are coordinate axes when the semiconductor laser device 101 is mounted on the laser light source 100. It coincides with the three-dimensional orthogonal coordinate axes shown in 2.

  As shown in FIG. 3, the semiconductor laser device 101 includes an n-type cladding layer 164 made of AlGaN or the like, an active layer 165 of MQW made of an InGaN well layer and a GaN barrier layer, AlGaN, etc. on a semiconductor substrate 163 such as GaN. A p-type cladding layer 166 is laminated by epitaxial growth. In the p-type cladding layer 166, two ridges 166a and 166b are formed. On the p-type cladding layer 166, the insulating layer 167 is formed on the flat surface where the ridges 166a and 166b are not formed and on the side surfaces of the ridges 166a and 166b, and the p-side electrode 168 is formed on the ridges 166a and 166b. ing. An n-side electrode 162 is formed on the lower surface of the semiconductor substrate 163.

  The n-side electrode 162 and the p-side electrode 168 are formed by vapor deposition of an alloy or the like based on Au, and a ridge portion is applied by applying a voltage so that a current flows from the p-side electrode to the n-side electrode. Stimulated emission of light occurs in the area of the active layer below 166a, 166b. At this time, the refractive index of the n-type cladding layer 164 and the p-type cladding layer 166 is lower than the refractive index of the active layer 165 formed therebetween, so that light is confined in the thin active layer 165. Further, the p-side electrode 168 formed outside the p-type cladding layer 166 is formed in a stripe shape, and since the insulating layer 167 is formed in the other region, the range of current flow is p The structure is limited to the range of the stripe width of the side electrode 168. As a result, the horizontal size of the light emitting area is limited. The light generated in the space limited to both vertical and horizontal directions is repeatedly reflected innumerably between the front and rear wall open facets of the active layer 165 to amplify the light and lead to the external emission of the laser light. .

  In the first embodiment, the laser light source 100 includes the semiconductor laser device 101 having a plurality of light emitting regions in one device structure. The semiconductor laser device 101 is a multi-emitter structure having two light emitting regions for emitting blue laser light having a wavelength of 450 nm. Specifically, a portion under the ridge portion 166a emits a first laser light. The light emitting region 101a is formed, and the lower portion of the ridge portion 166b is the second light emitting region 101b from which the second laser light is emitted. The first light emitting area 101a and the second light emitting area 101b are separated, and the distance between the light emitting centers of the first light emitting area 101a and the second light emitting area 101b is controlled by the distance between the ridges 166a and 166b. Ten to several hundred μm. Further, since the first light emitting region 101a and the second light emitting region 101b are formed by the same crystal growth process, the laser beams emitted from the first light emitting region 101a and the second light emitting region 101b have substantially the same optical characteristics. The wavelengths and the spread angles of the emitted light have almost the same characteristics. The external size of the semiconductor laser device 101 is several hundreds μm to several mm in length in the horizontal direction (x-axis direction) according to the number of light emitting areas and their intervals, and 100 μm in the vertical direction (y-axis direction) The longitudinal and longitudinal directions (z-axis direction) are on the order of several hundred μm to several mm.

  The laser beams emitted from the first light emitting region 101a and the second light emitting region 101b of the semiconductor laser device 101 are emitted as divergent light which spreads in an elliptical cone shape at a certain angle, as shown in FIG. The size of each light emitting region is several μm or less in the vertical direction which can be controlled in the nm order by crystal growth, and in the horizontal direction determined by the width of the ridge is several μm to 100 μm. For this reason, the laser light spreads largely in the vertical (y-axis) direction in which the width of the light emitting region is narrow due to diffraction, and the horizontal (x axis) direction in which the width of the light emitting region is wide is roughly 1⁄2 to It becomes a narrow spread angle of about 1/5. Since the distance between the light emission centers of the respective light emitting regions is only a few tens to several hundreds of micrometers, as described above, the laser from the first light emitting region is 1 mm away from the light emitting side end face of the semiconductor laser device 101 The light and the laser light from the second light emitting area begin to overlap in the horizontal direction. In the light emitting device according to the first embodiment, the semiconductor laser device 101 described with reference to FIGS. 3 and 4 is fixed on the submount 104 such that the directions of the x axis, y axis, and z axis match those in FIGS. The laser light from the first light emission area and the laser light from the second light emission area are almost entirely overlapped at the position where the aspheric lens 120 is disposed.

  Next, the aspheric lens 120 of the present invention will be described.

  The aspheric lens 120 is an optical element that converts laser light emitted as divergent light from the semiconductor laser element 101 into convergent light. The aspheric lens 120 has an inner and outer circumferential difference in refractive power, and the convergent light from the aspheric lens 120 is imaged by the paraxial ray 116 of the aspheric lens 120 on the focal plane 150 as shown in FIG. A light ray 117 passing through the outer periphery of the spherical lens 120 is imaged at a position 155 off the focal plane 150. The difference between the focal positions on the inner and outer peripheral sides of the aspheric lens 120 is referred to as spherical aberration. The spherical aberration is generated by the increase of the refractive power from the central part of the aspheric lens 120 toward the peripheral direction. Since it is necessary to eliminate this as much as possible in order to narrow the beam spot in the focal plane as much as possible, in the commercially available aspheric lens, the aspheric surface of the aspheric lens so that this spherical aberration becomes zero as much as possible. The shape is designed. From this, by adjusting the aspheric shape conversely, it is also possible to increase the amount of spherical aberration and adjust the focal position of the lens outer peripheral portion before and after the focal plane.

  On the other hand, as shown in FIG. 1, when the laser beam of Gaussian intensity distribution is narrowed by using an aspheric lens 120 having spherical aberration, that is, a lens whose refractive power increases toward the outer peripheral direction of the aspheric lens 120, the intensity is weak. Due to the effect of the light rays 117 on the outer peripheral side collecting inside and overlapping with the paraxial light rays 116, there is a plane where the light intensity distribution becomes uniform before the focal plane. The surface where the light intensity distribution becomes uniform controls the refractive power of the outer peripheral portion of the aspheric lens 120 by designing the aspheric shape, and changes the amount of spherical aberration to make the distance between the focal plane 150 and the aspheric lens 120 It can be adjusted to any position.

  In FIG. 5, a single laser beam is made to enter the aspheric lens 120 used in the first embodiment, and the horizontal (x-axis) direction, vertical (in the plane where the intensity distribution of the convergent light from the aspheric lens 120 becomes uniform) It is the figure which measured the intensity distribution of the light in the y-axis direction, and showed the result. 5 (a) is a beam profile showing the shape of laser light and its intensity distribution in reverse gray scale, FIG. 5 (b) is a diagram showing the intensity (integral value) distribution of light in the horizontal direction, FIG. c) shows the light intensity (integral value) distribution in the vertical direction. In order to obtain this measurement result, the laser light incident on the aspheric lens 120 has a radiation shape which is small in the x-axis direction and has a large spread angle in the y-axis direction.

  According to the measurement results of FIG. 5, the light intensity distribution in the y-axis direction with a large spread angle of the laser light is uniformed in the shape of the top hat by the action of the spherical aberration of the aspheric lens as shown in FIG. However, it has been found that the light intensity distribution in the x-axis direction with a small spread angle of the laser light does not have the shape of the top hat and is not uniform as shown in FIG. 5B. This is considered to be because, when the spread angle of the laser beam is small, the laser beam passes only the paraxial region of the aspheric lens, so that the correction effect of the peripherally transmitted beam can not be obtained. That is, even if the non-optical axis symmetrical laser light from the semiconductor laser device is made uniform by the aspheric lens having the optical axis symmetrical shape, the uniformity is made only in one of horizontal and vertical directions. There is a problem that it can not do.

  In the light emitting device of the first embodiment, the first light emitting region 101a and the second light emitting region 101b of the semiconductor laser element 101 are arranged in the horizontal (x-axis) direction in which the spread angle of the laser light is small. That is, the plurality of laser beams have different spread angles in the horizontal direction and the vertical direction, and are incident on the aspheric lens 120 in a state in which the spread angles are aligned in the direction in which the spread angles are small. The emission side end face of the laser light of the semiconductor laser element 101 is parallel to the main plane of the aspheric lens 120, and the first light emitting area 101a and the second light emitting area 101b are equidistant from the aspheric lens 120.

  In the light emitting device of the first embodiment, as shown in FIG. 2, the laser beam 110a from the first light emitting region 101a and the laser beam 110b from the second light emitting region 101b enter the aspheric lens 120 in a substantially overlapped state. Do. The laser beams 110a and 110b incident on the aspheric lens 120 are converted into convergent beams 111a and 111b, and the phosphors 130 are irradiated in an overlapping state. In the absence of the phosphor 130, the convergent lights 111a and 111b form an image in a completely separated state at the focal plane 150 after passing through the position.

  Next, in the light emitting device of Embodiment 1, the intensity distribution of the convergent lights 111a and 111b between the aspheric lens 120 and the focal plane will be described. 6 shows the intensity distribution at an arbitrary A-A position (see FIG. 2) between the phosphor 130 and the focal plane 150, and FIG. 7 shows the B-B position at which the phosphor 130 is disposed (FIGS. 1 and 2) FIG. 8 shows the intensity distribution at the C-C position (see FIG. 2) between the aspheric lens 120 and the phosphor 130, respectively. 6, 7 and 8, (a) is a beam profile showing the shape of laser light and its intensity distribution in reverse gray scale, (b) is the intensity (integrated value) of light in the horizontal (x-axis) direction FIG. 6C shows the distribution of light intensity (integral value) in the vertical (y-axis) direction.

  As shown in FIGS. 6 and 8, the light intensity has a bimodal or unimodal peak distribution at positions (A-A position, C-C position) before and after the position where the phosphor 130 is disposed. However, as shown in FIG. 7, at the position B-B where the phosphor 130 is disposed, the light intensity distribution is uniformed 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 aspheric lens 120 as in the case of FIG. 5, and in the horizontal direction, the Gaussian distributions of the light intensities of the two convergent lights 111a and 111b overlap each other. It is because that sum becomes uniform intensity distribution. That is, the aspheric lens 120 has a function of making the light intensity uniform in the direction in which the spread angles in the horizontal and vertical directions are large. In the present embodiment, the phosphor 130 is adjusted to be disposed at a position where such light intensity distribution is obtained. That is, the phosphor 130 is disposed at a position where the paraxial ray of light passing through the aspheric lens 120 is shifted to the aspheric lens 120 side with respect to the focal plane on which the image is formed.

  As an adjustment method for obtaining a uniform light intensity distribution other than the position adjustment of the phosphor 130, a method of fixing the position of the phosphor 130 and adjusting the distance between the semiconductor laser element 101 and the aspheric lens 120 There is. Specifically, by adjusting the position of the semiconductor laser element 101 in the z-axis direction or adjusting the position of the aspheric lens 120 in the z-axis direction, the positions of the focal planes 150 of the two convergent beams 111a and 111b are obtained. It is sufficient to change the degree of overlap of the two convergent lights at the position B-B, and to adjust the phosphor 130 so as to obtain a uniform light intensity distribution as shown in FIG.

  The aspheric lens 120 used in the present embodiment is perpendicular to the laser beam emitted from the semiconductor laser device 101 so that the light intensity distribution in the vertical (y-axis) direction becomes uniform at the B-B position. It is a lens whose spherical aberration has been optimized according to the spread angle in the y-axis direction.

  The phosphor 130 converts the combined light of the convergent lights 111a and 111b from the aspheric lens 120 into excitation light, converts part of it into fluorescence having a distribution of a larger wavelength, and emits the fluorescence to the outside. In addition, the remaining component of the excitation light which has not been converted into fluorescence is also scattered by the phosphor particles, the binder of the phosphor, and the mixed particles and emitted to the outside of the phosphor. Both fluorescence and scattered light of excitation light are emitted in a Lambertian distribution in two directions perpendicular to the phosphor formation surface. The human vision recognizes the sum of the emitted light that enters the eye as a color according to the ratio of fluorescence to scattered light, so by appropriately controlling the ratio by the thickness and density of the phosphor, white or any It is possible to form a wavelength distribution that looks like the color of.

  FIG. 9 is a view showing a wavelength distribution of light emitted from the phosphor 130 to the outside. In FIG. 9, the peak of the light intensity at a wavelength of 450 nm is due to the excitation light scattered without being converted to fluorescence by the phosphor 130, and the light intensity at a wavelength larger than that peak is converted to fluorescence by the phosphor 130 Light component. And the light of the wavelength component shown in FIG. 9 looks white to humans.

  As described above, in the light emitting device according to the first embodiment, the two laser beams 110a and 110b emitted from the semiconductor laser element 101 are incident on one aspheric lens to be convergent light, and the phosphor 130 is irradiated with excitation light and irradiation The phosphor 130 emits fluorescence. At this time, as shown in FIG. 7, the convergent light irradiated to the phosphor 130 is spot-like light having a uniform intensity distribution in the shape of the top hat in both the horizontal direction and the vertical direction. For this reason, the intensity of the excitation light irradiated to the phosphor 130 does not partially become strong, and the luminance saturation due to the increase of the light density and the temperature quenching and the deterioration due to the temperature rise are prevented.

  In the first embodiment, two laser beams are incident on the aspheric lens 120, but three or more laser beams may be incident. In this case, the light emitting regions of the semiconductor laser devices emitting the respective laser beams may be equally spaced, and it is easy to use a semiconductor laser device having a multi-emitter structure having three or more light emitting regions in one device structure. realizable. In addition, a plurality of laser beams are made to be incident on the aspheric lens in the same manner as in these embodiments using a semiconductor laser device having one light emitting region in one device structure without using a semiconductor laser device having a multi-emitter structure. May be

  Further, in the present embodiment, the wavelength of the laser beam from the semiconductor laser element 101 is blue light of 450 nm, but it may not be visible light or ultraviolet light of other wavelengths as long as it is the excitation wavelength of the phosphor. . However, in the case of ultraviolet light, it is necessary to generate a spectrum in the visible region according to the specifications of the light emitting device only by fluorescence, and when multiple wavelength distributions are required, phosphors are mixed or laminated and used. .

  The horizontal transverse mode of the semiconductor laser device 101 may be a single mode or a multi mode, but in general, a multi mode laser has higher output power, so in order to obtain a higher luminance light emitting device, the multi mode is desirable.

  Further, in the present embodiment, the distance between the light emitting regions of the semiconductor laser element 101 is set to several tens μm to several hundreds μm. However, the smaller the possible distance, the higher the utilization efficiency of the laser light incident on the lens. Since the position in the z direction where the light intensity distribution in the horizontal direction becomes uniform approaches the focal plane, the spot size of the irradiation laser light irradiated to the phosphor can be reduced as a result, and the luminance of the light from the phosphor can be reduced. Also go up. For this reason, it is desirable that the distance between the light emitting regions of the semiconductor laser device be 100 μm or less, if possible.

Second Embodiment
Embodiment 2 is a reflective illumination device using the light emitting device of the present invention. FIG. 10 is a cross-sectional view showing a schematic configuration of a lighting device of a second embodiment.

  As shown in FIG. 10, the illumination apparatus according to the second embodiment includes a semiconductor laser device 200 having a multi-emitter structure that emits two laser beams, and an aspheric lens that converts the laser beams emitted from the semiconductor laser device 200 into convergent light. 220, a phosphor 230 irradiated with the convergent light from the aspheric lens 220 as excitation light, and a reflector 260 (optical member) that reflects the light emitted from the phosphor 230 and emits the light to the outside (predetermined direction) Equipped with

  The reflector 260 is disposed between the aspheric lens 220 and the phosphor 230, and is provided with a through hole through which the convergent light from the aspheric lens 220 passes toward the phosphor 230. The reflector 260 has a reflecting surface 261 formed of a parabolic concave portion on the surface on the phosphor 230 side. The transparent substrate 231 is attached to the reflector 260 so as to close the concave portion constituting the reflective surface 261, and the phosphor 230 is attached to the central portion of the surface of the transparent substrate 231 on the reflective surface 261 side. The phosphor 230 has a shape of a square, a rectangle, a circle, or an ellipse having a width of several hundred μm to several nm in order to enhance the brightness. In addition, between the phosphor 230 and the transparent substrate 231, a total reflection film made of gold, aluminum, or an alloy thereof is used to reflect the emitted fluorescence and the scattered light to the incident surface side of the excitation light. It is formed.

  Since the semiconductor laser device 200 is heated to a high temperature during operation, it is in contact with a radiation fin 270 made of a metal having a high thermal conductivity such as aluminum or copper via a radiation grease as a heat radiation countermeasure. A fixing member 280 is attached to the surface of the reflector 260 opposite to the reflecting surface 261, and the semiconductor laser device 200 and the aspheric lens 220 are attached to the inside of the central hole of the fixing member 280.

  In the illumination device of the second embodiment, as in the light emitting device of the first embodiment, the two laser beams emitted from the semiconductor laser element 200 are incident on one aspheric lens 220 and become convergent light, and The light is emitted as excitation light, and the phosphor 230 generates fluorescence. The convergent light irradiated to the phosphor 230 is spot-like light having a uniform intensity distribution in the shape of a top hat in both the horizontal direction and the vertical direction as shown in FIG. For this reason, the intensity of the excitation light irradiated to the phosphor 230 does not become partially strong, and the luminance saturation due to the increase of the light density and the temperature quenching and the deterioration due to the temperature rise are prevented.

  The fluorescence generated from the phosphor 230 is reflected by the reflective surface 261 toward the reflector 260. The light reflected by the reflective surface 261 is transmitted through the transparent substrate 231 and emitted as illumination light 290 to the outside.

  The illumination device according to the present embodiment is intended to illuminate a narrow area located far away, such as spot lighting and a vehicle headlamp. For this reason, the reflecting surface 261 of the reflector 260 has a parabolic surface, and by arranging the phosphor 230 at the focal position of the parabolic surface, parallel light is irradiated to the outside. The reflecting surface may be an ellipsoid of revolution for the purpose of projecting the illumination light forward as diverging light.

  In the present embodiment, since the reflected light from the reflector 260 is emitted to the outside from the surface other than the position where the phosphor 230 is formed, the AR coating is applied to the entire front and back of the transparent substrate 231. It is done. Further, the heat generated by the phosphor 230 by the irradiation of the excitation light is dissipated from the transparent substrate 231. Therefore, as the material of the transparent substrate 231, transparent glass or sapphire glass having a higher thermal conductivity is suitable if importance is given to the effect of heat dissipation.

  In the lighting device of the second embodiment, the fluorescence from the phosphor 230 is reflected by the reflection surface 261 of the reflector 260 and emitted in a predetermined direction. For example, the light emitting device of the first embodiment shown in FIGS. In this case, a projection lens (optical member) for far-field irradiation may be disposed between the phosphor 130 and the focal plane 150 to constitute an illumination device. In this case, it is possible to emit the fluorescence generated from the phosphor 130 in the Lambertian distribution and the scattered component of the excitation light to a distant in a predetermined direction as substantially parallel light.

  As mentioned above, although the light-emitting device and illuminating device of this invention were demonstrated based on Embodiment 1 and 2, this invention is not limited to these embodiment. As long as the gist of the present invention does not deviate from the gist of the present invention, various modifications conceived by a person skilled in the art are applied to the first embodiment or the second embodiment, and another embodiment constructed by combining some components in the first and second embodiments is also Included within the scope of the present invention.

  According to the present invention, it is possible to suppress that the intensity of the laser beam irradiated to the phosphor is partially intensified, and to illuminate the fluorescence generated from the light emitting device and the light emitting device in which the luminance saturation, temperature quenching and deterioration of the phosphor are prevented. Examples of lighting devices used as light include medical lighting devices such as endoscopes, lighting devices for obtaining RGB light for displaying color images such as projectors, and lighting devices that emit light with a wavelength distribution suitable for plant cultivation For example, the present invention can be applied to all lighting devices of a system in which fluorescent light is irradiated with excitation light to obtain illumination light of an arbitrary color.

DESCRIPTION OF SYMBOLS 100 laser light source 101 semiconductor laser element 101a 1st light emission area 101b 2nd light emission area 102 stem 103 electrode pin 104 submount 105 protective cap 106 window part 110a, 110b laser beam 111a, 111b convergent light 116 paraxial light 117 light 120 aspheric Lens 121 lens holder 130 phosphor 131 transparent substrate 132 fixing member 140 housing 150 focal plane 155 position 162 n side electrode 163 semiconductor substrate 164 n type cladding layer 165 active layer 166 p type cladding layer 166a, 166b ridge portion 167 insulating layer 168p Side electrode 200 Semiconductor laser element 220 Aspheric lens 230 Phosphor 231 Transparent substrate 260 Reflector 261 Reflective surface 270 Heat radiation fin 280 Fixing member 290 Illumination light

Claims (5)

A laser light source for emitting a plurality of laser beams;
An aspheric lens that receives a plurality of laser beams emitted from the laser light source and converts the plurality of incident laser beams into convergent light;
And a fluorescent material that emits fluorescence light, which is emitted as excitation light from the convergent light from the aspheric lens.
The plurality of laser beams are incident on the aspheric lens in a state in which the spread angles in the horizontal direction and the vertical direction are different and are aligned in the direction in which the spread angle is small,
The light emitting device having the function of making the light intensity uniform in the direction in which the spread angle is large.   2. The light emitting device according to claim 1, wherein the phosphor is disposed at a position where a paraxial ray of light passing through the aspheric lens is shifted to the aspheric lens side with respect to a focal plane on which an image is formed.   The light emitting device according to claim 1 or 2, wherein in the laser light source, light emitting areas of the plurality of laser beams are arranged in the direction in which the spread angle is small.   The light emitting device according to claim 3, wherein the laser light source comprises a semiconductor laser device having a plurality of light emitting regions in one device structure. The light emitting device according to any one of claims 1 to 4.
And an optical member for emitting fluorescence generated from the light emitting device in a predetermined direction.