JP2009289976A - Light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device which is used together with a semiconductor laser element and can become a light source with reduced color unevenness. <P>SOLUTION: The light emitting device includes a semiconductor laser element and a wavelength conversion member which uses light emitted from the semiconductor laser element and emits light with different wavelength from light emitted from the semiconductor laser element, and it is configured by selecting dimension of the wavelength conversion member and the semiconductor laser element so that the projection area of the wavelength conversion member in the outgoing direction of light may become smaller than that of the semiconductor laser element in the direction of thickness. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a light emitting device, and more particularly to a light emitting device using a semiconductor laser element.

  Light emitting devices using light emitting diodes (LEDs) and semiconductor laser elements (LDs) have been proposed as light sources to replace incandescent bulbs and fluorescent lamps (Patent Documents 1 to 4). Patent Document 1 includes a semiconductor laser element and a phosphor composition, and the phosphor composition can receive light from the semiconductor laser element and emit light having a longer wavelength than the light from the semiconductor laser element. A light emitting device configured as described above is disclosed. Patent Documents 2 to 4 disclose light emitting devices in which an LED and a phosphor composition are combined. Patent Document 2 further discloses a light emitting device in which a semiconductor laser element and a phosphor composition are combined.

Devices combining a semiconductor laser element and a phosphor are also disclosed in Patent Documents 5-9. Patent Documents 5 and 6 propose the use of phosphors to reduce the coherence of the laser. Patent Document 7 discloses a flash device using a semiconductor laser device as a flash light source of a flash device used in a camera, and a phosphor as a laser light scattering member that uniformly scatters laser light emitted from the semiconductor laser device. It is proposed to use a coated reflector. Patent Document 8 discloses a semiconductor light emitting device that absorbs light emitted from a semiconductor light emitting element such as a semiconductor laser element with a phosphor and outputs visible light in a direction different from the laser light irradiation direction. . Patent Document 9 discloses a light emitting element that emits excitation light that excites a phosphor, a dispersion in which phosphors that emit fluorescence having a wavelength different from that of the excitation light are dispersed, and a lead frame that holds the light emitting element and the phosphor. And a light emitting device in which at least a part of light emitted from the phosphor is extracted to the outside.
Japanese Patent Laid-Open No. 2005-20010 Special Table 2002-53156 Japanese Patent Laid-Open No. 11-87784 JP-A-7-282609 JP 2004-128273 A JP-A-2005-191483 JP 2005-208333 A JP 2007-5383 A JP 2006-210887 A

  In order to obtain light of a specific color, a light-emitting device using light emitted from a semiconductor laser element can obtain light having a long wavelength by making light incident on a member containing a phosphor composition as described above. Configured as follows. However, in a member containing a phosphor composition used for a light emitting device, if the quality of the composition itself is not uniform, color unevenness occurs in the obtained light, and a light emitting device suitable for practical use cannot be obtained. There is. Therefore, the light emitting device is required to have little color unevenness. When the light from the semiconductor laser element is incident on a member having a predetermined size and shape containing the phosphor composition, color unevenness is likely to occur at the end of the member (that is, near the contour that defines the shape).

  In view of the above, the present invention provides a light-emitting device that uses laser light emitted from a semiconductor laser element as a light source, and is configured to reduce color unevenness. Objective.

  In order to achieve the above object, the present inventors have found that the color unevenness of the light emitting device can be reduced by adjusting the area of the member that converts the wavelength of light emitted from the semiconductor laser element. The present invention has been devised. That is, in the first aspect, the present invention provides a semiconductor laser element and a wavelength conversion member that emits light having a wavelength different from the wavelength of the light emitted from the semiconductor laser element by the laser light emitted from the semiconductor laser element. The wavelength conversion member is irradiated with the value of the maximum diameter in the cross section having the maximum diameter among the cross sections of the wavelength conversion member in the direction perpendicular to the light emission direction of the wavelength conversion member. The light emitting device is smaller than 120% of the maximum value of the beam diameter of the semiconductor laser element.

  It has been found that the color unevenness of the light emitting device is more likely to occur at the end portion of the member as the area of the wavelength conversion member that converts the wavelength of light emitted from the laser element increases. Therefore, in the light emitting device of the present invention, the value of the maximum diameter in the cross section having the maximum diameter among the cross sections of the wavelength conversion member in the direction perpendicular to the light emission direction of the wavelength conversion member is set as the wavelength conversion member. The color unevenness is effectively reduced by selecting the wavelength conversion member so that it does not exceed 120% of the beam diameter of the semiconductor laser element irradiated to. Here, the beam diameter indicates the major axis when the beam shape is elliptical.

  The maximum diameter value A (mm) preferably satisfies the following mathematical formula. If the wavelength conversion member is designed so as to satisfy this formula, color unevenness can be reduced more effectively.

（式中、Ａ（ｍｍ）は、波長変換部材の光の出射方向に対して垂直な方向の波長変換部材の断面のうち、最大の径を有する断面における当該最大の径の値であり、Ｄ（ｍｍ）は、半導体レーザ素子と波長変換部材との間の距離であり、Ｒ（°）は、半導体レーザ素子からの出射光の広がり角であり、ここで、「半導体レーザ素子からの出射光の広がり角」とは、ピーク強度の１／ｅ^２における全角である。ただし、（Ｄ−０．３）≦０のときは、（Ｄ−０．３）＝０．００１とする。）

(Wherein, A (mm) is the value of the maximum diameter in the cross section having the maximum diameter among the cross sections of the wavelength conversion member in the direction perpendicular to the light emitting direction of the wavelength conversion member, and D (Mm) is the distance between the semiconductor laser element and the wavelength conversion member, and R (°) is the spread angle of the emitted light from the semiconductor laser element. Here, “emitted light from the semiconductor laser element” The “angle of spread” is the full angle at 1 / e ² of the peak intensity, provided that (D−0.3) = 0.001 when (D−0.3) ≦ 0.

  Alternatively, in the second aspect, the present invention provides a semiconductor laser element and a wavelength conversion member that emits light having a wavelength different from the wavelength of the light emitted from the semiconductor laser element by the light emitted from the semiconductor laser element. And a projection area of the wavelength conversion member in the light emitting direction of the wavelength conversion member is smaller than a projection area of the semiconductor laser element in the thickness direction.

  As described above, it has been found that the color unevenness of the light emitting device is more likely to occur at the end of the member as the area of the wavelength conversion member that converts the wavelength of light emitted from the laser element increases. Therefore, in the light emitting device according to the second aspect of the present invention, the area of the wavelength conversion member, more precisely, the projected area of the wavelength conversion member in the light emission direction of the wavelength conversion member is set to the thickness of the semiconductor laser element. By making it smaller than the projected area in the vertical direction, color unevenness is effectively reduced.

  When receiving the same amount of light, the smaller the area of the wavelength conversion member, the higher the luminance of the light emitted from the wavelength conversion member. Therefore, the light emitting device of the present invention ensures high brightness by reducing the area of the wavelength conversion member. That is, according to this configuration, high luminance can be obtained by changing the dimensions of the wavelength conversion member or by adjusting the dimensions of the semiconductor laser element and the wavelength conversion member.

  The projected area of the wavelength conversion member in the light emission direction of the wavelength conversion member is preferably smaller than the area of the light emission surface of the semiconductor laser element. Thereby, color unevenness can be reduced more effectively.

  Moreover, it is preferable that the area of the wavelength conversion member is larger than the beam area of the semiconductor laser element irradiated to the wavelength conversion member. Or it is preferable to make the projection area of a wavelength conversion member larger than the near-field image (NFP) of the semiconductor laser element irradiated to the said wavelength conversion member. When the area of the wavelength conversion member is smaller than the beam area of the semiconductor laser element irradiated to the wavelength conversion member or the area of the near-field image, a part of the light from the semiconductor laser element does not enter the wavelength conversion member There is.

  In any of the first and second aspects of the present invention, when the semiconductor laser element and the wavelength conversion member are spatially separated, the wavelength conversion in the light emission direction from the wavelength conversion member is performed. It is preferable that the projected area of the member is larger than the beam area of the semiconductor laser element irradiated on the wavelength conversion member. If the area of the wavelength conversion member is smaller than the beam area of the semiconductor laser element irradiated to the wavelength conversion member, part of the light from the semiconductor laser element may not enter the wavelength conversion member.

When the light emitting device of the present invention includes a plurality of semiconductor laser elements,
A plurality of semiconductor laser elements;
A wavelength conversion member that emits light having a wavelength different from the wavelength of the light emitted from the semiconductor laser element by the laser light emitted from the semiconductor laser element;
The projected area of the wavelength converting member in the light emitting direction of the wavelength converting member is smaller than the total value of the projected areas in the thickness direction of the plurality of semiconductor laser elements,
Provided as a light emitting device. When a plurality of semiconductor laser elements are included, the projected area of the wavelength conversion member in the light emitting direction of the wavelength conversion member is smaller than the sum of the projected areas in the thickness direction of the respective semiconductor laser elements. By doing so, it is possible to obtain a light emitting device with reduced color unevenness and high luminance as described above.

  The semiconductor laser element and the wavelength conversion member are preferably spatially separated. When the wavelength conversion member is in contact with the semiconductor laser element, the wavelength conversion member may be deteriorated by heat generated by the semiconductor laser element, and the light emission efficiency of the wavelength conversion member is reduced, so that the spectral characteristics are deteriorated.

  The wavelength conversion member preferably contains a phosphor. By using the phosphor, the light from the semiconductor laser element can be converted into light having different desired wavelengths relatively easily.

  The light emitting device of the present invention has a casing having an opening in which a semiconductor laser element is housed, and the wavelength conversion member is positioned on the optical path of laser light emitted from the semiconductor laser element. It is preferable that it is arrange | positioned so that an opening part may be plugged up. That is, the light emitting device of the present invention is preferably provided as one package. The light-emitting device which is one package is easy to handle. The casing may be composed of two or more members.

  In the light emitting device of the present invention, the semiconductor laser element is preferably a blue semiconductor laser element having an emission peak wavelength at 360 nm to 480 nm. A white light source can be provided by using a blue semiconductor laser element.

  The light-emitting device of the present invention is configured by combining a semiconductor laser element and a wavelength conversion member, and determining the dimension of the wavelength conversion member in relation to the dimension of the semiconductor laser element or the laser beam, thereby reducing color unevenness. And provided as a light source with high brightness. Further, since the wavelength conversion member is provided apart from the semiconductor laser element, the light emission efficiency is high and the spectral characteristics are good. Furthermore, since the wavelength conversion member includes a phosphor, light having a desired wavelength can be obtained as coherence-free light, so that the light-emitting device of the present invention is provided as a safe light-emitting device. Furthermore, the light-emitting device of the present invention can be provided as a single package with good handleability.

[First embodiment]
One mode of a light-emitting device of the present invention is shown in FIG. 1A. FIG. 1A is a partial cross-sectional side view schematically showing an outline of a light emitting device 100 provided in the form of a package including a semiconductor laser element 20, a stem 40, and a laminated cap 60. In FIG. The vertical line is parallel to the thickness direction of the semiconductor laser element 20. The stem 40 has a substantially semi-cylindrical element mounting portion 42 protruding from the first surface 45 of the stem body 41, and the semiconductor laser element 20 is fixed to the element mounting portion 42. A submount 30 is interposed between the semiconductor laser element 20 and the element mounting portion 42 to promote heat dissipation of the semiconductor laser element 20. A lead pin 43 projects from the second surface 46 of the stem body 41 and is used for energization with an external device and attachment of the light emitting device 100.

The laminated cap 60 includes an outer cap 630 and an inner cap 640. The laminated cap 60 has an opening 61 for taking out the laser beam 26 to the outside. The opening 61 includes an opening 631 provided in the outer cap 63 and an opening 641 provided in the inner cap 64. Become.
The illustrated form has a configuration close to a conventionally used can-type semiconductor laser device, and the stem 40 and the laminated cap 60 constitute a casing for housing the semiconductor laser element 20 therein.

  The semiconductor laser element 20 is arranged so that the laser light 26 emitted from the end face 21 is emitted in the direction shown in the drawing. The wavelength conversion member 50 is disposed on the optical path of the laser light 26 so as to close the opening 61 of the cap. The wavelength conversion member 50 is disposed so as to close the opening 61 of the laminated cap 60. Here, “arranged so as to close” means arranging in the opening 61, arranging outside the laminated cap so as to cover the opening 61, and inside the laminated cap so as to cover the opening 61. Including placement. In the illustrated form, only one semiconductor laser element 20 is disposed. However, in another form, a plurality of semiconductor laser elements are arranged such that the wavelength conversion member is positioned on the optical path of the laser light emitted from the semiconductor laser element 20. May be arranged.

  The wavelength conversion member 50 is fitted into the opening 631 of the outer cap 630. The wavelength conversion member 50 is formed by dispersing phosphor particles 51 in a translucent material 52. The light incident on the wavelength conversion member 50 excites the phosphor particles 51 and / or is reflected by the phosphor particles 51 to excite the other phosphor particles 51 and is converted into light of another wavelength. Therefore, various colors can be obtained by combining the wavelength of light from the semiconductor laser element 20 and the phosphor particles 51. For example, when a white light source is formed using a blue laser element formed of a gallium nitride based semiconductor, the phosphor 51 that absorbs blue light and emits yellow light is used for the phosphor 51. White can be obtained by mixing yellow and yellow. If a red light emitting phosphor and a green light emitting phosphor are used together instead of the yellow light emitting phosphor 51, white can be obtained by mixing blue, red, and green. Details will be described later.

  In the light emitting device of the illustrated form, the light emission direction of the wavelength conversion member 50, that is, the light intensity among the light extracted from the wavelength conversion member 50 is the largest as indicated by the arrow L in the figure. Become. Therefore, the projection surface of the wavelength conversion member 50 in the direction of the arrow L, that is, the surface on which the wavelength conversion member is projected from the direction parallel to the arrow L to the surface perpendicular to the arrow L (that is, when the arrow L is in the z-axis direction). FIG. 1B shows a surface projected onto the xy plane. As shown in FIG. 1B, the projection surface 53 in the direction of arrow L of the wavelength conversion member 50 is circular, and the area of the circle shown in the figure is the projected area in the thickness direction of the semiconductor laser element 20 (shown in FIG. 1A). Smaller than the area of the semiconductor laser device 20. By reducing the area of the wavelength conversion member 50 as described above, light with reduced color unevenness can be extracted. Further, the extracted light has high luminance. The projected area in the thickness direction of the semiconductor laser element is a semiconductor projected onto a plane perpendicular to the thickness direction from the thickness direction, that is, the direction parallel to the direction in which the layers constituting the semiconductor laser element are sequentially laminated. The area of the laser element 20.

  As the projection area in the arrow L direction of the wavelength conversion member 50 is smaller, the color unevenness is further reduced. However, if it is too small, part of the light emitted from the semiconductor laser element 20 does not reach the wavelength conversion member 50. Therefore, although depending on the distance between the wavelength conversion member 50 and the semiconductor laser element 20, at least the projection area in the arrow L direction of the wavelength conversion member 50 is the beam of the semiconductor laser element 20 irradiated on the wavelength conversion member 50. The area and / or the area of the near-field image is preferably larger.

  The shape of the projected area of the wavelength conversion member 50 in the arrow L direction is not limited to a circle, and may be a rectangle, a triangle, an ellipse, or the like.

Below, each structural member is explained in full detail.
<Semiconductor laser element 20>
The semiconductor laser element 20 is formed by forming a semiconductor such as GaAlN, ZnS, ZnSe, SiC, GaP, GaAlAs, AlN, InN, AlInGaP, InGaN, GaN, or AlInGaN on a substrate as a light emitting layer. Examples of the semiconductor structure include a homo structure having a MIS junction, a PIN junction, and a PN junction, a hetero structure, and a double hetero structure. Various emission wavelengths can be selected from ultraviolet light to infrared light depending on the material of the semiconductor layer and the degree of mixed crystal. The light emitting layer may have a single quantum well structure or a multiple quantum well structure which is a thin film in which a quantum effect is generated.

  When considering use outdoors, it is preferable to use a gallium nitride-based compound semiconductor as a semiconductor material capable of forming a high-brightness semiconductor laser element. In red, gallium-aluminum-arsenic-based semiconductors and aluminum- It is preferable to use an indium / gallium / phosphorous semiconductor, but various semiconductors may be used depending on the application.

  When a gallium nitride compound semiconductor is used, a material such as sapphire, spinel, SiC, Si, ZnO, or GaN single crystal is used for the semiconductor substrate. In order to form gallium nitride with good crystallinity with high productivity, it is preferable to use a GaN single crystal substrate. An example of the structure of a device using a nitride compound semiconductor is as follows. A buffer layer such as GaN or AlN is formed on the GaN single crystal substrate. Furthermore, a first contact layer made of N or P-type GaN, an active layer made of an InGaN thin film having a quantum effect, a clad layer made of P or N-type AlGaN, and a second layer made of P or N-type GaN. The contact layers can be formed in order. Gallium nitride-based compound semiconductors exhibit N-type conductivity without being doped with impurities. In the case of forming a desired N-type gallium nitride semiconductor such as improving luminous efficiency, Si, Ge, Se, Te, C or the like is preferably introduced as appropriate as an N-type dopant.

  On the other hand, when a P-type gallium nitride semiconductor is formed, a P-type dopant such as Zn, Mg, Be, Ca, Sr, or Ba is doped. Since a gallium nitride based semiconductor is difficult to be converted into a P-type simply by doping with a P-type dopant, it is necessary to make it P-type by annealing it by heating in a furnace, low electron beam irradiation, plasma irradiation or the like after introducing the P-type dopant. The semiconductor wafer thus formed is partially etched to form positive and negative electrodes. Thereafter, the semiconductor laser device 20 can be formed by cutting the semiconductor wafer into a desired size.

  The semiconductor laser element 20 is preferably one having an emission peak wavelength at 360 nm to 480 nm, and more preferably one having an emission peak wavelength at 400 nm to 470 nm. For example, those having an emission peak wavelength in the vicinity of 445 nm can be preferably used.

<Wavelength conversion member 50>
(Base material 52)
As the base material of the wavelength conversion member 50, a translucent material such as ceramics, glass, and resin can be used. In particular, glass is suitable as a base material because it is superior in heat dissipation, light resistance, heat resistance, and weather resistance compared to a resin. This is because the phosphor particles 51 absorb the laser light and have heat, so that it is necessary to dissipate the heat from the wavelength conversion member 50.
Examples of the glass base material include substances containing Al ₂ O ₃ , SiO ₂ , ZrO ₂ , ZnO, ZnSe, AlN, GaN, and the like.
The resin base material is preferably a thermosetting resin excellent in heat resistance, and examples thereof include epoxy resins, modified epoxy resins, silicone resins, modified silicone resins, acrylate resins, and urethane resins.
The shape of the wavelength conversion member 50 is not particularly limited, but various shapes such as a plano-convex lens shape, a flat plate shape, a disc shape, a truncated cone shape having a trapezoidal cross section, a spherical shape, and an egg shape can be employed.

(Phosphor particles 51)
The phosphor particles 51 used as the wavelength conversion material may be any material that absorbs the laser light from the semiconductor laser element and converts the wavelength into light having a different wavelength. In particular, the phosphor particles 51 are preferably a material that absorbs light from the semiconductor laser element 20 and emits light having an emission peak wavelength of 475 nm to 750 nm. For example, nitride phosphors / oxynitride phosphors / sialon phosphors mainly activated by lanthanoid elements such as Eu and Ce, lanthanoid elements such as Eu, and transition metal elements such as Mn. Alkaline earth halogen apatite phosphor, alkaline earth metal borate phosphor, alkaline earth metal aluminate phosphor, alkaline earth silicate phosphor, alkaline earth sulfide phosphor, alkali Earth thiogallate phosphor, alkaline earth silicon nitride phosphor, germanate phosphor, rare earth aluminate phosphor, rare earth silicate phosphor or Eu mainly activated by lanthanoid elements such as Ce It is preferable that it is at least any one or more selected from organic and organic complexes mainly activated by the lanthanoid element. As specific examples, the following phosphors can be used, but are not limited thereto.

Nitride-based phosphors mainly activated with lanthanoid elements such as Eu and Ce are M ₂ Si ₅ N ₈ : Eu, MAlSiN ₃ : Eu, MAl _1-X B _X SiN ₃ : Eu (M is Sr , Ca, Ba, Mg, and Zn. 0 <X <1). In addition to M ₂ Si ₅ N ₈ : Eu, MSi ₇ N ₁₀ : Eu, M _1.8 Si ₅ O _0.2 N ₈ : Eu, M _0.9 Si ₇ O _0.1 N ₁₀ : Eu (M Is at least one selected from Sr, Ca, Ba, Mg, and Zn.
An oxynitride phosphor mainly activated by a lanthanoid element such as Eu or Ce is MSi ₂ O ₂ N ₂ : Eu (M is at least one selected from Sr, Ca, Ba, Mg, Zn) Etc.).

Eu, sialon phosphors activated mainly with lanthanoid elements such as Ce _{is, M p / 2 Si 12-} p-q Al p + q O q N 16-p: Ce, M-Al-Si-O-N (M is at least one selected from Sr, Ca, Ba, Mg, and Zn. Q is 0 to 2.5, and p is 1.5 to 3).
Alkaline earth halogen apatite phosphors mainly activated by lanthanoid compounds such as Eu and transition metal elements such as Mn include M ₅ (PO ₄ ) ₃ X: R (M is Sr, Ca, Ba). X is at least one selected from F, Cl, Br and I. R is any one of Eu, Mn, Eu and Mn. Etc.).

The alkaline earth metal borate phosphor has M ₂ B ₅ O ₉ X: R (M is at least one selected from Sr, Ca, Ba, Mg, Zn. X is F, Cl , Br, or I. R is Eu, Mn, or any one of Eu and Mn.).
Alkaline earth metal aluminate phosphors include SrAl ₂ O ₄ : R, Sr ₄ Al ₁₄ O ₂₅ : R, CaAl ₂ O ₄ : R, BaMg ₂ Al ₁₆ O ₂₇ : R, BaMg ₂ Al ₁₆ O ₁₂ : R, BaMgAl ₁₀ O ₁₇ : R (R is Eu, Mn, or any one of Eu and Mn).

Examples of the alkaline earth sulfide phosphor include La ₂ O ₂ S: Eu, Y ₂ O ₂ S: Eu, and Gd ₂ O ₂ S: Eu.
Examples of rare earth aluminate phosphors mainly activated with lanthanoid elements such as Ce include Y ₃ Al ₅ O ₁₂ : Ce, (Y _0.8 Gd _0.2 ) ₃ Al ₅ O ₁₂ : Ce, Y _{3 (Al 0.8 Ga 0.2) 5 O} 12: Ce, and the like (Y, Gd) 3 (Al , Ga) YAG -based phosphor represented by the composition formula of _{5 O 12.} Further, there are Tb ₃ Al ₅ O ₁₂ : Ce, Lu ₃ Al ₅ O ₁₂ : Ce, etc. in which a part or all of Y is substituted with Tb, Lu or the like.

Other phosphors include ZnS: Eu, Zn ₂ GeO ₄ : Mn, MGa ₂ S ₄ : Eu (M is at least one selected from Sr, Ca, Ba, Mg, Zn. X is At least one selected from F, Cl, Br, and I).

The phosphor described above contains at least one selected from Tb, Cu, Ag, Au, Cr, Nd, Dy, Co, Ni, and Ti instead of Eu or in addition to Eu as desired. You can also.
In addition, a phosphor other than the above phosphors having the same performance and effect can also be used.

  These phosphors can use phosphors having emission spectra in yellow, red, green, and blue by the excitation light of the semiconductor laser element, and emit light in yellow, blue-green, orange, etc., which are intermediate colors. A phosphor having a spectrum can also be used. By using these phosphors in various combinations, light emitting devices having various emission colors can be manufactured.

For example, using a GaN-based compound semiconductor that emits blue light, a Y ₃ Al ₅ O ₁₂ : Ce or (Y _0.8 Gd _0.2 ) ₃ Al ₅ O ₁₂ : Ce fluorescent material is irradiated to convert the wavelength. Do. A light emitting device that emits white light by a mixed color of light from a semiconductor laser element and light from a phosphor can be provided.

For example, CaSi ₂ O ₂ N ₂ : Eu or SrSi ₂ O ₂ N ₂ : Eu that emits light from green to yellow, and (Sr, Ca) ₅ (PO ₄ ) ₃ Cl: Eu that emits blue light as a phosphor. By using the phosphor 60 composed of Ca ₂ Si ₅ N ₈ : Eu or CaAlSiN ₃ : Eu that emits red light, a light-emitting device that emits white light with good color rendering can be provided. This uses the three primary colors of red, blue, and green, so the desired white light can be achieved simply by changing the blend ratio of the first phosphor and the second phosphor. Can do.

  Alternatively, for example, a phosphor that emits green light with high color purity and a phosphor that emits red light with high color purity are mixed and used, and light is emitted from a semiconductor laser element emitting blue light. Thus, it is also possible to obtain RGB emission line spectra. Alternatively, by using two semiconductor laser elements that emit blue and red light respectively in one package, and irradiating the light emitted from these with a phosphor that emits green color with high color purity, It is possible to obtain RGB emission line spectra. Instead of using a plurality of semiconductor laser elements, a semiconductor laser element having a plurality of ridge (that is, multi-ridge or multi-stripe) structures may be used. A light emitting device that provides such an emission line spectrum is useful as, for example, a projector.

  Regardless of which phosphor is used, the mixing amount (concentration) of the phosphor particles to the base material takes into account the balance between the amount of laser light transmitted from the semiconductor laser element and the amount of light emitted from the phosphor particles. Determined.

<Outer cap 630, Inner cap 640>
The outer cap 630 can be formed using a metal material having high thermal conductivity such as Ag, Cu, Al, Au, Ni, and Mo. As the material of the inner cap 640, a material having a lower thermal conductivity than that of the outer cap 630 is preferably selected. In particular, stainless steel, Kovar, Ti, Zr, Mn and the like that can be welded to the stem are suitable.

<Stem 40>
The stem can be formed using copper, iron, nickel-iron alloy, copper-tungsten, copper-molybdenum alloy, or a combination of these. In addition to the substantially cylindrical shape, the stem may be formed into a shape such as a substantially elliptical column, a substantially truncated cone shape, a substantially rectangular shape, or a cup shape. Moreover, a level | step difference or a dent can be provided and fixation with a cap can be made favorable.

[Second form]
Next, another embodiment of the light emitting device of the present invention is shown in FIG. In FIG. 2, it should be noted that the same reference numerals as those shown in FIG. 1A denote the same members. The light emitting device 200 shown in FIG. 2 has a casing composed of three members. The casing includes a support 70 having a lead pin 71 and a surface 72 for mounting the semiconductor laser element 20, a cylindrical member 80 having a reflector 81 formed therein, and a cap 90 having a wavelength conversion member 50. . The semiconductor laser element 20 is disposed so that the end face 21 that emits the laser light 26 faces the reflector 81 so that the laser light 26 that it oscillates is emitted toward the reflector 80. The wavelength conversion member 50 is disposed on an optical path through which light from the reflector 81 passes.

  In this light emitting device, the laser light 26 is reflected by the reflector 81 and enters the wavelength conversion member 50. Also in this embodiment, the wavelength conversion member 50 is obtained by dispersing the phosphor particles 51 in the base material 52. The light incident on the wavelength conversion member 50 excites the phosphor particles 51 and / or is reflected by the phosphor particles 51 to excite the other phosphor particles 51 and is converted into light of another wavelength. The light emitting direction of the wavelength conversion member 50 is the largest in the direction indicated by the arrow L also in this embodiment. Therefore, also in this embodiment, the projected area (not shown) of the wavelength conversion member 50 in the direction of the arrow L is the projected area (direction parallel to the arrow L in the shown embodiment) of the semiconductor laser element (the direction parallel to the arrow L). (Not shown), thereby reducing color unevenness and ensuring that light with high luminance is obtained.

  The preferable dimensions and specific dimensions of the semiconductor laser element 20 and the wavelength conversion member 50 are as described above in relation to the first embodiment, and thus the details thereof are omitted here.

  In this embodiment, the casing is composed of a support, a cylindrical member surrounding the semiconductor laser element 20, and a cap in which the wavelength conversion member 50 is incorporated. These members will be described below.

  The support is formed using copper, iron, nickel-iron alloy, copper-tungsten, copper-molybdenum alloy, a combination of these, and the like, like the stem of the first form. In addition to the substantially cylindrical shape, the support may have a substantially elliptical column shape, a substantially truncated cone shape, a substantially rectangular shape, a cup shape, or the like. Moreover, a level | step difference or a dent can be provided and fixation with a cylindrical member can be made favorable.

  The cylindrical member is formed using a metal material having high thermal conductivity such as Ag, Cu, Al, Au, Ni, and Mo. The cylindrical member may be a cylinder having a circular cross section, or may have a substantially rectangular or substantially triangular cross section. In this embodiment, it is preferable to use a cylindrical member having a substantially rectangular cross section so that the reflector can be easily formed.

  In the illustrated form, the reflector 81 is formed integrally with the cylindrical member 80. In another form, the reflector may be formed as an independent member made of the same material as or different from that of the casing. The light reflecting surface can be arbitrarily formed such as a gentle curve, a cup shape, or a taper shape. The light reflecting surface may also be formed with a reflective film in order to improve the reflectance.

  A cap consists of the wavelength conversion member 50 and the part surrounding it. The material surrounding the wavelength conversion member 50 is not particularly limited, and may be a light-transmitting material such as transparent glass, or heat conduction such as Ag, Cu, Al, Au, Ni, or Mo. It may be a high rate metal material. The shape and dimensions of the cap are appropriately selected according to the shape of the cylindrical member to which the cap is attached.

  Since the other members constituting the light emitting device of the second embodiment are as described above in relation to the first embodiment, the description thereof is omitted here.

[Embodiment 3]
Yet another embodiment of the light emitting device of the present invention is shown in FIG. Note that in FIG. 3, the same reference numerals as those shown in FIG. 1A denote the same members. The light emitting device 300 shown in FIG. 3 has a casing made of three members. The casing includes a support 70 having a surface 72 for mounting the semiconductor laser element 20, a cylindrical member 80 having reflectors 81 a and 81 b formed therein, and a cap having a wavelength conversion member 50. The semiconductor laser element 20 includes two reflectors 81a in which a laser beam 26 oscillated from the semiconductor laser element 20 and a laser beam (so-called monitor beam) 28 from an end surface 22 opposed to the end surface 21 from which the laser beam 26 is emitted are arranged in a casing. End surfaces 21 and 22 are arranged so as to face the reflectors 81a and 81b, respectively, so as to be emitted toward the reflectors 81b and 81b, respectively. The wavelength conversion member 50 is disposed on an optical path through which light from the reflectors 81a and 81b passes.

  The laser beam 26 and the monitor beam 28 reflected by the reflector are incident on the wavelength conversion member 50. Also in this embodiment, the wavelength conversion member 50 is obtained by dispersing the phosphor particles 51 in the base material 52. The light incident on the wavelength conversion member 50 excites the phosphor particles 51 and / or is reflected by the phosphor particles 51 to excite other phosphor particles 51 and is converted into light of another wavelength. The luminous intensity of the light extracted from the wavelength conversion member 50 is the largest in the direction indicated by the arrow L also in this embodiment. Therefore, also in this embodiment, the projected area (not shown) of the wavelength conversion member 50 in the direction of the arrow L is the projected area (direction parallel to the arrow L in the shown embodiment) of the semiconductor laser element (the direction parallel to the arrow L). (Not shown), thereby reducing color unevenness and ensuring high brightness.

  Among the members constituting the light emitting device of this embodiment, the support, the cylindrical member, the reflector, and the cap are as described in relation to the second embodiment, and the other members are implemented first. Therefore, the description thereof is omitted here.

[Embodiment 4]
FIG. 4 shows still another embodiment of the light emitting device of the present invention. In FIG. 4, it should be noted that the same reference numerals as those shown in FIGS. 1A and 2 represent the same members. The light emitting device 400 shown in FIG. 4 has a casing formed of two members. The casing includes a support body 70 provided with a surface 72 on which the element mounting portion 42 for mounting the semiconductor laser element is disposed, and a cylindrical cap 90 that covers the support body 70. The semiconductor laser element 20 is disposed so that the end face 21 that emits the laser light 26 faces the side surface of the cap 90 so that the laser light 26 that it oscillates is emitted toward the side surface of the cap 90. . The wavelength conversion member 50 is disposed on the side surface of the cylindrical cap 90 so as to be on the optical path through which the laser light 26 passes. Therefore, according to this form, it is possible to extract light from the side portion of the cylindrical cap.

  The laser beam 26 enters the wavelength conversion member 50. Also in this embodiment, the wavelength conversion member 50 is obtained by dispersing the phosphor particles 51 in the base material 52. The light incident on the wavelength conversion member 50 excites the phosphor particles 51 and / or is reflected by the phosphor particles 51 to excite other phosphor particles 51 and is converted into light of another wavelength. The luminous intensity of the light extracted from the wavelength conversion member 50 is greatest in the direction indicated by the arrow L in this embodiment. Therefore, also in this embodiment, the projected area (not shown) in the direction of the arrow L of the wavelength conversion member 50 is the projected area (not shown) in the thickness direction of the semiconductor laser element (in the illustrated embodiment, the vertical direction of the paper surface). In other words, color unevenness is reduced and high luminance is ensured.

[Embodiment 5]
Alternatively, as shown in FIG. 5, the light emitting device of the present invention may include a photodiode 65 in the casing. In FIG. 5, it should be noted that the same reference numerals as those shown in FIGS. 1A, 2 and 4 denote the same members. The photodiode 65 detects light that has been wavelength-converted and is reflected and / or scattered by the phosphor particles 51. Thereby, it is possible to know whether the laser light 26 has been wavelength-converted as desired, whether the wavelength conversion member 50 is not dropped (= the photodiode does not detect light), or the like. The photodiode 65 may be disposed on the support 70 as shown, or may be disposed on the inner wall of the cap 90. If necessary, the photodiode 65 may be fixed to the support 70 or the cap 90.

  Any of the light emitting devices described above with reference to the drawings may be modified as follows. For example, in the form shown in FIG. 1, the wavelength conversion member 50 has a wavelength value of the maximum diameter in the cross section having the maximum diameter among the cross sections perpendicular to the light emission direction (direction of the arrow L). The size may be larger than that shown on the condition that it is smaller than 120% of the beam diameter of the semiconductor laser element 20 irradiated to the conversion member. Similarly, the dimensions of the wavelength conversion member may be changed in other embodiments. Here, the dimension of the wavelength conversion member is defined by “the value of the maximum diameter of the cross section having the maximum diameter among the cross sections perpendicular to the light emission direction”. For example, when the shape is a convex lens or when the wavelength conversion member is an inverted truncated cone as shown in FIG. 6, it is considered that the diameter changes depending on the cutting position. The value of the maximum diameter of the wavelength conversion member is more preferably smaller than 110% of the beam diameter.

  In this case, the maximum diameter of the wavelength conversion member is A (mm), the distance between the semiconductor laser element and the wavelength conversion member is D (mm), and the spread angle of the emitted light from the semiconductor laser element is R ( It is preferable to select A or D and / or R so that A satisfies the following formula:

  D is generally about 0.02 to 5.0 mm, and R is generally about 10 to 65 mm. D can be, for example, 0.3 mm, and R can be, for example, 42 °, in which case A satisfies 0.00038 ≦ A ≦ 0.72 mm. Alternatively, D can be 0.5 mm, and R can be, for example, 55 °, in which case A (mm) satisfies 0.12 ≦ A ≦ 1.2 mm.

  Alternatively, in any of the illustrated embodiments, the wavelength conversion member may be designed so that the projected area of the wavelength conversion member in the light emission direction is smaller than the area of the light emission surface of the semiconductor laser element. Even in that case, color unevenness can be effectively reduced. In any of the above modifications, the projected area of the wavelength conversion member in the light emitting direction of the wavelength conversion member is the area of the near-field image of the laser element or the beam area of the semiconductor laser element irradiated to the wavelength conversion member. Is preferably larger.

  The light-emitting device of the present invention can be used for projectors, special inspection devices that require high brightness, automobile headlights, lighting devices, and the like.

FIG. 1A is a partial cross-sectional side view showing one embodiment of a light-emitting device of the present invention. FIG. 1B is a schematic diagram illustrating a projection surface of the wavelength conversion member 50 in the direction of the arrow L. FIG. 2 is a partial side sectional view showing another embodiment of the light emitting device of the present invention. FIG. 3 is a partial side sectional view showing another embodiment of the light emitting device of the present invention. FIG. 4 is a partial side sectional view showing another embodiment of the light emitting device of the present invention. FIG. 5 is a partial cross-sectional side view showing another embodiment of the light emitting device of the present invention. FIG. 6 is a partial cross-sectional side view showing another embodiment of the light-emitting device of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Semiconductor laser apparatus 20 Semiconductor laser element 21, 22 End surface 26 Laser light 28 Monitor light 30 Submount 40 Base (stem)
41 Stem Main Body 42 Element Placement Unit 43 Lead Pin 44 Stem Surface 50 Wavelength Conversion Member 51 Phosphor Particle 52 Base Material 53 Projection Surface in Direction of Arrow L of Wavelength Conversion Member 60 Stack Cap 61 Stack Cap Opening 630 First Cap 631 First cap opening 640 Second cap 641 Second cap opening 65 Photodiode 70 Support 71 Lead pin 72 Mounting surface 80 Cylindrical member 81, 81a, 81b Reflector 90 Cap 100, 200, 300, 400 Light emitting device

Claims (10)

A semiconductor laser element;
A wavelength conversion member that emits light having a wavelength different from the wavelength of the light emitted from the semiconductor laser element by the laser light emitted from the semiconductor laser element;
The semiconductor laser in which the wavelength conversion member is irradiated with the value of the maximum diameter in the cross section having the maximum diameter among the cross sections of the wavelength conversion member in a direction perpendicular to the light emission direction of the wavelength conversion member Less than 120% of the maximum beam diameter of the element,
Light emitting device. The light emitting device according to claim 1, wherein the maximum diameter value A (mm) is in a range satisfying the following mathematical formula.

(Wherein, A (mm) is the value of the maximum diameter in the cross section having the maximum diameter among the cross sections of the wavelength conversion member in the direction perpendicular to the light emitting direction of the wavelength conversion member, and D (Mm) is the distance between the semiconductor laser element and the wavelength conversion member, and R (°) is the spread angle of the emitted light from the semiconductor laser element. Here, “emitted light from the semiconductor laser element” The “angle of spread” is the full angle at 1 / e ² of the peak intensity, provided that (D−0.3) = 0.001 when (D−0.3) ≦ 0. A semiconductor laser element;
A wavelength conversion member that emits light having a wavelength different from the wavelength of the light emitted from the semiconductor laser element by the laser light emitted from the semiconductor laser element;
The projected area of the wavelength converting member in the light emitting direction of the wavelength converting member is smaller than the projected area of the semiconductor laser element in the thickness direction;
Light emitting device.   4. The light emitting device according to claim 3, wherein a projected area of the wavelength converting member in the light emitting direction of the wavelength converting member is smaller than an area of a light emitting surface of the semiconductor laser element.   The light emitting device according to claim 4, wherein a projected area of the wavelength conversion member in a light emission direction of the wavelength conversion member is larger than an area of a near-field image of the semiconductor laser element.   The semiconductor in which the semiconductor laser element and the wavelength conversion member are spatially separated, and the projection area of the wavelength conversion member in the light emission direction from the wavelength conversion member is irradiated to the wavelength conversion member The light emitting device according to claim 1, wherein the light emitting device is larger than a beam area of the laser element. A plurality of semiconductor laser elements;
A wavelength conversion member that emits light having a wavelength different from the wavelength of the light emitted from the semiconductor laser element by the laser light emitted from the semiconductor laser element;
The projected area of the wavelength converting member in the light emitting direction of the wavelength converting member is smaller than the total value of the projected areas in the thickness direction of the plurality of semiconductor laser elements,
Light emitting device.   The light-emitting device according to claim 1, wherein the wavelength conversion member includes a phosphor.   A casing having an opening in which the semiconductor laser element is housed; and closing the opening of the casing so that the wavelength conversion member is positioned on an optical path of a laser beam emitted from the semiconductor laser element. The light emitting device according to claim 1, wherein the light emitting device is arranged as described above.   The semiconductor laser element emits laser light having an emission peak wavelength at 360 nm to 480 nm, and the wavelength conversion member converts the wavelength of the laser light to emit light having an emission peak wavelength at 485 nm to 650 nm. The light emitting device according to claim 1.

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