JP4822919B2 - Light emitting device and vehicle headlamp - Google Patents

Description

  The present invention relates to a light emitting device and a vehicle headlamp, and more particularly to a light emitting device having good luminous efficiency and color rendering and a vehicle headlamp using the light emitting device.

  Patent Document 1 and Non-Patent Document 1 each disclose a light emitting device that emits white light using a semiconductor laser element as an excitation light source.

  FIG. 7 shows a schematic configuration of an example of a conventional light emitting device that emits white light using a semiconductor laser element as an excitation light source. This conventional light emitting device includes a semiconductor laser element 700, a lens 701 for condensing laser light oscillated from the semiconductor laser element 700, an optical fiber portion 703, and a light emitting portion 704 made of a resin in which a phosphor is dispersed. And.

In this conventional light emitting device, the laser light oscillated from the semiconductor laser element 700 is condensed on the lens 701 and coupled to the optical fiber portion 703 with high efficiency. A part of the laser light propagated through the optical fiber portion 703 is irradiated on the phosphor in the light emitting portion 704, and the yellow light emitted from the phosphor irradiated with the laser light and the blue laser oscillated from the semiconductor laser element 700 are emitted. White light is emitted from the light emitting device by the light.
JP 2005-205195 A Narukawa Yukio, Nagabuchi Shinichi, Tamaki Hiroto, Mukai Takashi, “Development of High Brightness White Light Source Using GaN-Based Light Emitting Elements”, Journal of Applied Physics, Vol. 74, No. 11, 2005, p. 1423

  As described above, when a semiconductor laser element is used instead of a light emitting diode element as an excitation light source of a light emitting device, a broad area type semiconductor laser element (a stripe width serving as a light emitting region is set to about 1.5 μm as a normal area) W (Watt) class light output can be easily extracted from a semiconductor laser element of sub-mm size by providing a large number of stripe structures with a stripe width of about 1.5 μm. (That is, a high light output can be obtained from a semiconductor laser device having a relatively small size).

  Further, when a semiconductor laser element is used as an excitation light source of a light emitting device, laser light is oscillated only in the direction of the resonator of the semiconductor laser element, so that it can be easily coupled with optical components such as optical fibers and lenses. There is also a point that can be done.

  Therefore, in order to increase the luminous flux per unit area and obtain light emission with high luminance, it is preferable to use a semiconductor laser element as an excitation light source of the light emitting device.

  Here, the Stokes loss was calculated when the peak wavelength of the laser light oscillated from the semiconductor laser element as the excitation light source was set to 405 nm and 455 nm, and the Stokes loss was 20% when the peak wavelength was 405 nm. In the case of 455 nm, it was 9.8%.

  Therefore, it is understood that a semiconductor laser element that oscillates a laser beam having a peak wavelength of about 455 nm is preferably used as an excitation light source of the light emitting device, rather than a semiconductor laser element that oscillates a laser beam having a peak wavelength of about 405 nm. The Stokes loss is an energy loss that occurs when one photon of laser light serving as excitation light is absorbed by the phosphor and converted to one electron and further to one photon. The smaller the Stokes loss, the smaller the Stokes loss. It shows that the luminous efficiency of the light emitting device is large.

  However, when a semiconductor laser element that oscillates laser light having a peak wavelength of 455 nm is used as an excitation light source of the light emitting device, an average color rendering index (Ra) of light emitted from the light emitting device can be obtained only about 72. There wasn't.

  Further, as a result of intensive studies by the present inventors, when a semiconductor laser element that oscillates a laser beam having a peak wavelength of 455 nm is used, the half width of the peak wavelength in the emission spectrum of the laser beam is only about several nm. It was. Therefore, it has been found that the color rendering property in the blue vicinity region becomes extremely poor in light emission from the light emitting device, and as a result, the average color rendering index (Ra) cannot be increased. Therefore, a configuration using a semiconductor laser element that oscillates a laser beam having a peak wavelength of about 455 nm cannot be used in a light emitting device in a field of application or general illumination that requires high luminance such as for medical use or projector. It was.

  An object of the present invention is to provide a light emitting device with good luminous efficiency and color rendering and a vehicle headlamp using the light emitting device.

The present invention is a light emitting device including a semiconductor laser element and a light emitting unit that emits light when irradiated with laser light oscillated from the semiconductor laser element, and the laser light oscillated from the semiconductor laser element is The blue region has a peak wavelength, and the light-emitting portion includes a phosphor. The phosphor has a half-value width wider than the half-value width of the peak wavelength of the laser beam when irradiated with the laser beam. A yellow light emitting phosphor that emits light with a peak wavelength in the yellow region when irradiated with laser light, and a green light that emits light with a peak wavelength in the green region when irradiated with laser light The blue light-emitting phosphor includes at least one selected from the group consisting of a light-emitting phosphor and a red light-emitting phosphor that emits light having a peak wavelength in the red region by irradiation with laser light. And particles made of GaN, which is composed of a coating layer made of GaN coating the particles, light emitted from the light emitting unit is a white light, white light, including at least the light emitted from the blue light emitting phosphor A light emitting device.

  Here, in the light emitting device of the present invention, the peak wavelength of the laser light and the peak wavelength of the light emitted from the blue light emitting phosphor may be in the range of 440 nm to 480 nm, respectively.

In the present invention, “a composition in which the first composition is different from the second composition” only needs to be different from the second composition in at least one of the elements constituting the first composition and the composition ratio.

  In the light emitting device of the present invention, the active layer of the semiconductor laser element may be made of a nitride semiconductor.

  Further, the light emitting device of the present invention may have a configuration in which the semiconductor laser element and the light emitting unit are installed in a concave cup that reflects light from the light emitting unit.

  In addition, the light emitting device of the present invention includes an optical fiber portion that includes a core portion and a cladding portion that covers the periphery of the core portion and has a refractive index lower than that of the core portion, and the laser light oscillated from the semiconductor laser element is an optical fiber portion It is good also as a structure with which a light emission part is irradiated via.

  The light-emitting device of the present invention includes an optical fiber portion that includes a core portion and a cladding portion that covers the periphery of the core portion and has a refractive index lower than that of the core portion, and the laser light oscillated from the semiconductor laser element is the optical fiber portion. The light emitting part is irradiated through the light emitting part, and the light emitting part is formed so as to cover the periphery of the clad part. The light transmitting part transmits at least part of the laser light propagating through the core part to the clad part. A region may be formed, and at least a part of the laser light may be irradiated to the light emitting unit after passing through the transmission region.

  The light-emitting device of the present invention includes an optical fiber portion that includes a core portion and a cladding portion that covers the periphery of the core portion and has a refractive index lower than that of the core portion, and the laser light oscillated from the semiconductor laser element is the optical fiber portion. The light emitting part is irradiated through the lens, and the light emitting part is installed in a concave cup that reflects the light from the light emitting part, and the light from the light emitting part is emitted to the outside through a lens provided in the opening of the cup. It is good also as a structure.

  Furthermore, the present invention is a vehicle headlamp including any one of the light emitting devices described above.

  ADVANTAGE OF THE INVENTION According to this invention, the light-emitting device with favorable luminous efficiency and color rendering property, and the vehicle headlamp using the light-emitting device can be provided.

  Embodiments of the present invention will be described below. In the drawings of the present invention, the same reference numerals represent the same or corresponding parts.

(Embodiment 1)
FIG. 1 schematically shows a configuration of a preferable example of the light emitting device of the present invention. This light-emitting device includes a concave cup 100 that includes a semiconductor laser element 101 and a light-emitting unit 102 that emits light when irradiated with laser light emitted from the semiconductor laser element 101.

  Here, the semiconductor laser element 101 oscillates a laser beam having a peak wavelength in a blue region (a wavelength range of 440 nm to 480 nm). In the present invention, the “peak wavelength” means the wavelength of light having the strongest emission intensity in the emission spectrum.

As an example of the configuration of such a semiconductor laser device 101, an n-type GaN buffer layer, an n-type Al _0.1 Ga _0.9 N clad layer having a layer thickness of 0.95 μm, and an n-type GaN having a layer thickness of 100 nm are formed on an n-type GaN substrate. A guide layer, a barrier layer represented by a composition formula of In _v Ga _1-v N (0 ≦ v ≦ 1), and a well layer represented by a composition formula of In _w Ga _1-w N (0 ≦ w ≦ 1) Each of the active layers having a multiple quantum well structure repeated twice, a p-type Al _0.2 Ga _0.8 N evaporation prevention layer having a layer thickness of 18 nm, a p-type GaN light guide layer having a layer thickness of 100 nm, and a p-type Al _0.1 layer having a layer thickness of 0.5 μm A configuration in which a Ga _0.9 N cladding layer and a p-type GaN contact layer having a layer thickness of 0.1 μm are sequentially stacked, and electrodes are formed on the back surface of the n-type GaN substrate and the surface of the p-type GaN contact layer, respectively. In the present embodiment, the active layer is adjusted so as to oscillate a laser beam having a peak wavelength of 455 nm. However, the present invention is not limited to this, and a laser beam having a peak wavelength in a wavelength range of 440 nm to 480 nm. Can be oscillated.

  One end of a wire 103 is bonded to the electrode on the upper surface side of the semiconductor laser element 101, and the other end of the wire 103 is connected to a current extraction terminal 104 provided on the cup 100. Further, the electrode on the lower surface side of the semiconductor laser element 101 is connected to a current extraction terminal (not shown) provided in the cup 100 on the lower side of the semiconductor laser element 101.

  The light emitting unit 102 is made of a resin plate containing a phosphor. Here, the phosphor included in the light emitting unit 102 is irradiated with the laser light oscillated from the semiconductor laser element 101 and has a blue region (440 nm or more and 480 nm or less having a half width wider than the half width of the peak wavelength of the laser light. A blue light emitting phosphor that emits light having a peak wavelength in the wavelength range). In the present invention, the “half-value width” means the width of the emission peak when the emission intensity of the emission peak is half in the emission spectrum.

  The phosphor included in the light emitting unit 102 is a yellow light emitting phosphor that emits light having a peak wavelength in a yellow region (wavelength range of 540 nm or more and 580 nm or less) by irradiation of laser light oscillated from the semiconductor laser element 101. The green light-emitting phosphor that emits light having a peak wavelength in the green region (wavelength range of 500 nm to 540 nm) by irradiation of the laser light oscillated from the semiconductor laser element 101 and the laser light oscillated from the semiconductor laser element 101 And at least one selected from the group consisting of red light-emitting phosphors that emit light having a peak wavelength in the red region (wavelength range of 610 nm to 650 nm).

Here, in the present embodiment, the phosphor included in the light emitting unit 102 includes a yellow light emitting phosphor represented by the formula YAG: Ce that emits light having a peak wavelength of 550 nm, and In _0.1 Ga _0.9 N. A peak wavelength composed of a particle having a particle diameter of 3 nm made of a nitride semiconductor represented by the composition formula of FIG. 5 and a coating layer having a thickness of 5 μm made of a nitride semiconductor represented by the composition formula of GaN covering the particles is about And a blue light-emitting phosphor that emits light of 460 nm. In the present embodiment, a resin plate made of silicone resin is used as the resin plate used for the light emitting unit 102.

  The cup 100 is made of a material such as alumina, for example, and has a function of reflecting light emitted from the light emitting unit 102.

  Therefore, in this light emitting device, a part of the laser light oscillated from the semiconductor laser element 101 is irradiated to the light emitting unit 102. Then, white light is emitted from the light emitting unit 102 by the laser light oscillated from the semiconductor laser element 101, the light emission from the blue light emitting phosphor, and the light emission from the yellow light emitting phosphor. Then, the white light is reflected from the inner surface of the cup 100 and then emitted from the opening on the upper surface of the cup 100.

  Here, a light emitting device having the same configuration as the light emitting device of the first embodiment except that the light emitted from the light emitting device of the first embodiment and the blue light emitting phosphor are not included (comparison) The average color rendering index (Ra) of each light emitted from the example light emitting device) was calculated. As a result, the average color rendering index (Ra) of light emitted from the light emitting device of the comparative example was 71, but the average color rendering index (Ra) of 85 light was emitted from the light emitting device of the first embodiment. I was able to improve.

  FIG. 2 shows emission spectra of light emitted from the light-emitting device of Embodiment 1 and light emitted from the light-emitting device of the comparative example. In FIG. 2, the solid line indicates the emission spectrum of the light emitted from the light emitting device of Embodiment 1, and the broken line indicates the emission spectrum of the light emitted from the light emitting device of the comparative example. In addition, an emission spectrum having a wavelength of 480 nm or more of light emitted from the light emitting device of Embodiment 1 has a spectral shape that overlaps with an emission spectrum of light emitted from the light emitting device of the comparative example. The description is omitted.

  As shown in FIG. 2, in the emission spectrum of the light-emitting device of Embodiment 1, the half-value width of the emission peak in the vicinity of a wavelength of 450 nm is wider than that of the light-emitting device of the comparative example. Since the light emitting device of the comparative example does not include the blue light emitting phosphor, the blue light emitting phosphor is wider than the half-value width of the peak wavelength of the laser light oscillated from the semiconductor laser element 101. It can be seen that light having a peak wavelength in a blue region having a half width (wavelength range of 440 nm to 480 nm) is emitted. Further, since the light emitting device of the comparative example does not contain the blue light emitting phosphor, the improvement in the color rendering property in the light emitting device of Embodiment 1 is due to the presence of the blue light emitting phosphor. it is conceivable that.

  In the light emitting device of the first embodiment having such a configuration, it is possible to achieve high light emission efficiency and high color rendering properties such that the light emission efficiency is about 80 lm / W and the average color rendering index (Ra) is about 85.

  In the present invention, the blue light-emitting phosphor is made of a semiconductor material that can be adjusted so as to absorb the light having the peak wavelength of the laser beam that easily becomes excitation light by controlling the composition, size, and the like. It is preferable to use a phosphor. When a phosphor made of a semiconductor material is used, a part of the laser light oscillated from the semiconductor laser element is absorbed by the phosphor, and a very broad light is emitted at substantially the same peak wavelength as the laser light. it can.

Further, a particle having a particle diameter of 3 nm made of a nitride semiconductor represented by the composition formula of In _0.1 Ga _0.9 N and a coating layer having a layer thickness of 5 μm made of a nitride semiconductor represented by the composition formula of GaN covering the particles, The blue light-emitting phosphor composed of the above can be produced by a chemical synthesis method such as a general reverse micelle method.

In the present invention, the blue light-emitting phosphor is composed of a particle composed of a nitride semiconductor represented by a composition formula of In _0.1 Ga _0.9 N and a nitride semiconductor represented by a composition formula of GaN covering the particles. Not limited to the configuration with the coating layer, the material of the particles and the coating layer may be a group III-V nitride semiconductor having a composition other than In _0.1 Ga _0.9 N and GaN, and the above two layers comprising the particles and the coating layer It is not limited to the structure.

  In the present invention, the material constituting the blue light-emitting phosphor is not limited to the group III-V nitride semiconductor, and for example, a group II-VI compound semiconductor such as ZnCdSSe may be used.

  In the above, the peak wavelength of the light emitted from the blue light emitting phosphor is set in a wavelength region where the emission spectrum of the laser light emitted from the semiconductor laser and the emission spectrum emitted from the yellow light emitting phosphor overlap. It is preferable. In this case, the color rendering properties of the light emitted from the light emitting device can be improved more efficiently.

  In the present invention, the configuration of the phosphor included in the light emitting unit is not limited to the above configuration. For example, the configuration of the phosphor included in the light emitting unit is changed to the blue light emitting phosphor described above, It can also be set as the structure by a green light emission fluorescent substance and said red light emission fluorescent substance.

  In the above description, the upper surface of the concave cup 100 is an opening. However, in the present invention, a diffusion plate for diffusing white light emitted from the light emitting unit 102 may be provided in the opening.

(Embodiment 2)
FIG. 3 schematically shows a configuration of another preferred example of the light emitting device of the present invention. This light emitting device includes a semiconductor laser element 101 having the same configuration as that of the first embodiment as an excitation light source, an optical fiber portion 302, and a light emitting portion 303.

  Here, the semiconductor laser element 101 is installed in the package 301 together with the lens 300. One end of the optical fiber portion 302 is attached to the package 301. Further, the other end of the optical fiber portion 302 is attached to the light emitting portion 303. The package 301 may include a Peltier element for cooling the semiconductor laser element 101.

  The optical fiber portion 302 includes a core portion and a cladding portion that covers the periphery of the core portion and has a lower refractive index than the core portion. Here, the core part is made of quartz glass having almost no absorption loss with respect to light having the peak wavelength of the laser light oscillated from the semiconductor laser element 101, and the cladding part is refracted more than the quartz glass constituting the core part. Consists of low-rate plastic materials.

The light emitting unit 303 is made of a resin plate containing a phosphor. Here, the phosphor included in the light-emitting portion 303 includes a nitride having a particle diameter of 3 nm made of a nitride semiconductor represented by a composition formula of In _0.1 Ga _0.9 N and a nitride represented by a composition formula of GaN covering the particles. A blue light-emitting phosphor having the same configuration as that of the first embodiment, which is formed of a coating layer made of a semiconductor and having a layer thickness of 5 μm, is included. Here, as in the first embodiment, the blue light emitting phosphor emits light having a peak wavelength of about 460 nm when irradiated with laser light having a peak wavelength of 455 nm oscillated from the semiconductor laser element 101. .

The light emitting unit 303 includes a yellow light emitting phosphor represented by the formula CaSiAlON: Eu ²⁺ and a red light emitting phosphor represented by the formula 0.5MgF ₂ .3.5MgO · GeO ₂ : Mn ^4+. include. A resin plate made of silicone resin is used as the resin plate used for the light emitting unit 303.

  In this light emitting device, the laser light oscillated from the semiconductor laser element 101 is collected by the lens 300. The laser light condensed by the lens 300 propagates through the core portion of the optical fiber portion 302 and is irradiated on the light emitting portion 303. Then, the laser light emitted from the semiconductor laser element 101, the light emitted from the blue light emitting phosphor, the light emitted from the yellow light emitting phosphor, and the light emitted from the red light emitting phosphor are emitted from the light emitting unit 303. White light is emitted. FIG. 4 shows an emission spectrum of light emitted from the light-emitting device of Embodiment 2.

  In the light emitting device of the second embodiment having such a configuration, it is possible to achieve high light emission efficiency and high color rendering properties such that the light emission efficiency is about 75 lm / W and the average color rendering index (Ra) is about 90.

  In the present invention, the configuration of the optical fiber portion is not limited to the above, and for example, the core portion may be formed of polymethyl methacrylate (PMMA) or the like.

  In the present invention, the shape of the light emitting unit 303 may be a lens shape that can control the direction of light emitted from the light emitting unit 303.

  In addition, the light-emitting device of Embodiment 2 can be suitably applied to an optical system of an endoscope that requires color rendering properties and high luminance.

(Embodiment 3)
FIG. 5 schematically shows a configuration of another preferred example of the light emitting device of the present invention. This light emitting device includes a semiconductor laser element 101 having the same configuration as that of the first embodiment as an excitation light source, an optical fiber portion 505, and a light emitting portion 504.

  Here, the optical fiber portion 505 includes a core portion 501 and a cladding portion 503 that covers the periphery of the core portion 501 and has a refractive index lower than that of the core portion 501. The core portion 501 is made of quartz glass having almost no absorption loss with respect to light having the peak wavelength of the laser light oscillated from the semiconductor laser element 101, and the cladding portion 503 is refracted more than the quartz glass constituting the core portion 501. Consists of low-rate plastic materials.

  In addition, a transmission region 502 that can transmit at least part of the laser light propagating through the core portion 501 is formed in a part of the core portion 501. Here, the transmissive region 502 can be formed by, for example, irradiating the core portion 501 with KrF excimer laser light having a wavelength of 248 nm to modulate the refractive index of a part of the core portion 501.

Further, the light emitting unit 504 is formed so as to cover the periphery of the clad unit 503 of the optical fiber unit 505. Here, the light emitting unit 504 is formed of a resin plate containing a phosphor. In addition, the phosphor included in the light emitting portion 504 includes a nitride semiconductor represented by a composition formula of nitride having a particle diameter of 3 nm and a GaN covering the particles, which is composed of a nitride semiconductor represented by a composition formula of In _0.1 Ga _0.9 N. And a blue light-emitting phosphor having the same configuration as that of the first embodiment, which is composed of a coating layer having a layer thickness of 5 μm. Here, as in the first embodiment, the blue light emitting phosphor emits light having a peak wavelength of about 460 nm when irradiated with laser light having a peak wavelength of 455 nm oscillated from the semiconductor laser element 101. .

The light emitting portion 504 includes a yellow light emitting phosphor represented by the formula CaSiAlON: Eu ²⁺ and a red light emitting phosphor represented by the formula 0.5MgF ₂ .3.5MgO · GeO ₂ : Mn ^4+. include. Note that a resin plate made of silicone resin is used as the resin plate used for the light emitting unit 504.

  In this light emitting device, the laser light oscillated from the semiconductor laser element 101 propagates through the core portion 501 of the optical fiber portion 505. Here, part of the laser light propagating through the core portion 501 is transmitted from the transmission region 502 to the cladding portion 503. Then, the laser light transmitted through the cladding part 503 is irradiated from the cladding part 503 to the light emitting part 504. Then, the laser light emitted from the semiconductor laser element 101, the light emitted from the blue light emitting phosphor, the light emitted from the yellow light emitting phosphor, and the light emitted from the red light emitting phosphor are emitted from the light emitting unit 504. White light is emitted.

  Also in the light emitting device of Embodiment 3 having such a configuration, high luminous efficiency and high color rendering can be realized.

  Since the light emitting device of the third embodiment having such a configuration can emit white light in a linear shape, it is used for a field where linear illumination is required, for example, for a backlight of a liquid crystal display device. It can be suitably applied to a light source or the like.

  In the above, the transmission region 502 is formed by modulating the refractive index of a part of the core portion 501, but in the present invention, the difference in refractive index between the core portion 501 and the light emitting portion 504 is reduced. By increasing the amount of laser light propagating through the core part 501 to the clad part 503, the interface between the core part 501 and the clad part 503 may be used as a transmission region, or by providing a scattering material in the clad part 503, etc. A transmission region may be formed in a part of the clad portion 503.

(Embodiment 4)
FIG. 6 schematically shows a configuration of another preferred example of the light emitting device of the present invention. Here, the light emitting device includes a light emitting device having the same configuration as that of the second embodiment except for the light emitting portion. The light emitting unit 303 is installed in the concave cup 601, and the lens 600 is installed in the opening of the cup 601. In FIG. 6, only one package 301 in which the semiconductor laser element 101 and the lens 300 are installed is described from the viewpoint of preventing the description of the drawing from becoming complicated. The light emitting device shown in FIG. 3 has a configuration in which three packages 301 are connected to different optical fiber portions 302 respectively.

  The lens 600 has a function of controlling the direction of light emitted from the light emitting unit 303. The cup 601 is formed by coating silver on the inner surface of a cup made of a plastic material, and has a function of reflecting light emitted from the light emitting unit 303 and light reflected by the lens 600 by the inner surface of the cup 601. Have.

  In the light emitting device according to the present embodiment, the core portion having a diameter of 2 mm is used as the optical fiber portion 302, and the semiconductor laser element 101 is configured so that the light output of the laser light propagating through one optical fiber portion 302 is 3W. By adjusting the light output, laser light with a total luminous flux of about 400 lm can be emitted from one optical fiber portion 302. Here, as the configuration of the semiconductor laser element 101, for example, a stripe width of about 10 μm to 20 μm, or a stripe width of about 2 μm and an array structure is preferably used.

In the light emitting device of the present embodiment, light having high luminance and color rendering properties similar to a halogen lamp with a total luminous flux of about 1200 lm and a luminance of about 25 cd / mm ² can be emitted.

Therefore, when the light-emitting device of the present embodiment is applied to a vehicle headlamp, it greatly exceeds the total luminous flux (200 lm) and luminance (20 cd / mm ² ) of light emitted from the conventional vehicle headlamp. The light-emitting device of this embodiment can be preferably applied to a vehicle headlamp.

  Furthermore, since the light emitting device of this embodiment uses a semiconductor laser element as an excitation light source, when the light emitting device of this embodiment is applied to a vehicle headlamp, it is instantaneously desired after power-on. There is also an advantage that a light amount of light can be turned on.

  The vehicle headlamp to which the light emitting device of the present embodiment is applied can be mounted on a vehicle such as a four-wheeled vehicle, a two-wheeled vehicle, or a bicycle.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  ADVANTAGE OF THE INVENTION According to this invention, the light-emitting device with favorable luminous efficiency and color rendering property, and the vehicle headlamp using the light-emitting device can be provided.

It is a typical perspective perspective view which shows the structure of a preferable example of the light-emitting device of this invention. 4 is a diagram illustrating emission spectra of light emitted from the light emitting device of Embodiment 1 and light emitted from the light emitting device of a comparative example. FIG. It is a schematic diagram which shows the structure of another preferable example of the light-emitting device of this invention. 6 is a diagram illustrating an emission spectrum of light emitted from the light-emitting device of Embodiment 2. FIG. It is a schematic diagram which shows the structure of another preferable example of the light-emitting device of this invention. It is a schematic diagram which shows the structure of another preferable example of the light-emitting device of this invention. It is a schematic diagram which shows the structure of an example of the conventional light-emitting device which used the semiconductor laser element as an excitation light source.

Explanation of symbols

  100,601 cup, 101,700 semiconductor laser element, 102,303,504,704 light emitting part, 103 wire, 104 current extraction terminal, 300,600,701 lens, 301 package, 302,505,703 optical fiber part, 501 Core part, 502 transmission region, 503 cladding part.

Claims (8)

A light emitting device comprising: a semiconductor laser element; and a light emitting unit that emits light when irradiated with laser light oscillated from the semiconductor laser element,
The laser light oscillated from the semiconductor laser element has a peak wavelength in a blue region,
The light emitting unit includes a phosphor,
The phosphor includes a blue light emitting phosphor that emits light having a peak wavelength in a blue region having a half-value width wider than a half-value width of the peak wavelength of the laser light by irradiation of the laser light, Yellow light emitting phosphor that emits light with a peak wavelength in the yellow region upon irradiation, green light emitting phosphor that emits light with a peak wavelength in the green region upon irradiation with the laser light, and a peak in the red region upon irradiation with the laser light Including at least one selected from the group consisting of red light-emitting phosphors that emit light of a wavelength;
The blue light emitting phosphor is composed of particles made of InGaN and a coating layer made of GaN covering the particles ,
The light emission from the light emitting unit is white light, and the white light includes at least light emission from the blue light emitting phosphor .   2. The light emitting device according to claim 1, wherein a peak wavelength of the laser light and a peak wavelength of light emitted from the blue light emitting phosphor are in a range of 440 nm to 480 nm, respectively.   The light emitting device according to claim 1, wherein an active layer of the semiconductor laser element is made of a nitride semiconductor.   4. The light emitting device according to claim 1, wherein the semiconductor laser element and the light emitting unit are installed in a concave cup that reflects light from the light emitting unit. 5.   An optical fiber portion comprising a core portion and a cladding portion covering the periphery of the core portion and having a refractive index lower than that of the core portion, and laser light oscillated from the semiconductor laser element emits the light through the optical fiber portion. The light-emitting device according to claim 1, wherein the light-emitting device is irradiated to a portion. An optical fiber portion that includes a core portion and a cladding portion that covers the periphery of the core portion and has a refractive index lower than that of the core portion, and the laser light emitted from the semiconductor laser element emits the light through the optical fiber portion. A light emitting device for irradiating the part,
The light emitting part is formed so as to cover the periphery of the clad part,
A transmission region for transmitting at least a part of the laser light propagating through the core part to the cladding part is formed in a part of the optical fiber part,
4. The light emitting device according to claim 1, wherein at least a part of the laser light is irradiated to the light emitting unit after passing through the transmission region. 5. An optical fiber portion that includes a core portion and a cladding portion that covers the periphery of the core portion and has a refractive index lower than that of the core portion, and the laser light emitted from the semiconductor laser element emits the light through the optical fiber portion. A light emitting device for irradiating the part,
The light emitting part is installed in a concave cup that reflects light from the light emitting part,
4. The light emitting device according to claim 1, wherein light from the light emitting unit is emitted to the outside through a lens provided in an opening of the cup. 5.   A vehicle headlamp comprising the light emitting device according to claim 1.

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