JP2005109289A - Light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting device capable of outputting parallel beams of higher luminance. <P>SOLUTION: In the light emitting device comprising a light-emitting element and a translucent member arranged oppositely to the first and second light-emitting surfaces of the light-emitting element and capable of projecting light from the light-emitting element from a radiation direction, the light emitting element has a plurality of light-emitting parts on the first and second light-emitting surfaces and the translucent member comprises a lens part for projecting direct light from the light-emitting element, a light reflection part for reflecting the direct light at least from the light-emitting element and a light-projecting part for projecting reflected light reflected at least by the light reflection part. Each of the lens part and the light reflection part has a focus on each different light-emitting part among the plurality of light-emitting parts of the light-emitting element. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a light emitting device intended to emit light from a light emitting element while controlling the light within a specific range.

  In recent years, light emitting devices using LEDs have been used as light sources for lighting devices for obtaining spot light such as projectors, in-vehicle lighting, and reading lights. As such a light-emitting device, a device in which a reflector is formed, a focal point of the light-emitting device is provided on the light-emitting element, and light from the light-emitting element is reflected by the reflector and taken out to the outside to obtain mainly parallel light is known. ing.

JP-A-1-205480

However, the light-emitting element that is actually used has a plurality of light-emitting parts, whereas the focal point of the reflector is placed at the center of the light-emitting surface of the light-emitting element. It becomes difficult.
SUMMARY OF THE INVENTION An object of the present invention is to provide a light emitting device that can realize spot light with high brightness and better controllability.

  In order to solve the above-described problems, a light-emitting device according to claim 1 of the present invention is provided with a light-emitting element and the first light-emitting surface and the second light-emitting surface of the light-emitting element so as to face each other. A light-emitting device that emits light in a radiation direction, wherein the light-emitting element has a plurality of light-emitting portions on the first light-emitting surface and the second light-emitting surface, The lens unit includes a lens unit that emits direct light from the light emitting element, a light reflecting unit that reflects at least direct light from the light emitting element, and a light emitting unit that emits reflected light reflected by at least the light reflecting unit. The light reflecting portion has a focal point at a different light emitting portion among the plurality of light emitting portions of the light emitting element.

  With such a configuration, light from different light emitting units can be controlled by the lens unit and the light reflecting unit, so that the utilization efficiency of light from the light emitting element can be increased and high-luminance parallel light can be obtained. it can.

  In the light-emitting device according to claim 2 of the present invention, the lens has a first focal point at the center of the first light-emitting surface of the light-emitting element, and the light reflecting portion is a second light-emitting surface on the second light-emitting surface of the light-emitting element. It has a focal point.

  By having the second focal point on the second light emitting surface away from the first light emitting surface of the light emitting element, it becomes possible to increase the light collection efficiency, especially when a relatively large light emitting element is used. , You can get a remarkable effect.

  The light emitting device according to claim 3 of the present invention is characterized in that the light emitting part emits only the light reflected by the light reflecting part out of the light from the light emitting element.

  By setting it as such a structure, the light from all the light emitting elements can be taken out outside by controlling with the light reflection part and lens part of a translucent member.

  The light emitting device according to claim 4 of the present invention is characterized in that the light reflecting portion is a parabolic surface.

  With such a configuration, the light reflected by the paraboloid in the light from the light emitting element becomes parallel light, and can be incident on the light emitting portion with the same incident angle.

  The light emitting device according to claim 5 of the present invention is characterized in that the light emitting portion is formed of a flat surface.

  With such a configuration, the parallel light obtained from the light reflecting portion can also be extracted outside while maintaining the parallelness of the respective lights.

  The light emitting device according to claim 6 of the present invention is characterized in that the light from the light emitting element reflected by the light reflecting portion is set in a range where the incident angle with respect to the light emitting portion is larger than 0 ° and smaller than the critical angle. And

  By setting it as such a structure, the light from a light emitting element can be taken out effectively from the light emission part. In addition, the diameter of the light emitting device can be reduced by inclining the light reflecting portion of the translucent member in a direction perpendicular to the first light emitting surface of the light emitting element.

  The light-emitting device according to claim 7 of the present invention is characterized in that the translucent member is adjacent to the light-emitting element through an air layer.

  By setting it as such a structure, the light emission which generate | occur | produced inside the light emitting element can be efficiently guide | induced to a translucent member.

  The light emitting device according to claim 8 of the present invention is characterized in that a light reflecting material is formed on the outer surface of the light reflecting portion.

  With such a configuration, the utilization efficiency of light from the light emitting element can be increased.

  The light emitting device according to claim 9 of the present invention is characterized in that the light emitting element is mounted through a submount.

  By adopting such a configuration, the height can be adjusted by the submount, and the range of light emitted from the light emitting element that can be reflected by the light reflecting portion of the translucent member can also be made wider. It is also possible to obtain parallel light.

  The light-emitting device according to claim 10 of the present invention is characterized in that the light-emitting element is made of a gallium nitride compound semiconductor.

  By having such a configuration, a better effect of the present invention can be obtained.

  In the light emitting device according to the present invention, since the lens portion and the light reflecting portion of the translucent member have a focal point on each of the light emitting portions of the light emitting element, light can be efficiently extracted in the radiation direction. It is possible to provide a light emitting device that emits light or only a specific range.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is a schematic cross-sectional view showing a configuration of a light emitting device according to an embodiment of the present invention, and FIG. 2 is a schematic diagram showing a traveling direction of light from a light emitting element in the light emitting device according to the embodiment of the present invention. It is sectional drawing. Such a light emitting device includes a light emitting element 2, a mounting substrate 3 on which a wiring pattern for mounting the light emitting element is formed, and a translucent member 1 provided so as to cover the light emitting element. The translucent member 1 is provided in contact with the light emitting element 2 having the first light emitting surface 201 and the second light emitting surface 202 or through an air layer, and condenses the light from the light emitting element 2 to the outside. The lens unit 101 takes out light, the light from the light emitting element 2 becomes parallel reflected light, and the light reflecting unit 102 reflects the light in a desired direction, and the light emitting unit 103 takes out the reflected light to the outside. Here, in the present invention, the upper surface (light emitting surface) of the light emitting element is defined as a first light emitting surface, and the side surface (side end surface) of the light emitting element is defined as a second light emitting surface. Moreover, let the direction of the light reflected by the light reflection part be a radiation direction.

  A light emitting element used in such a light emitting device is generally optically designed as a point light source, but actually has a plurality of light emitting portions, and the light distribution is not uniform. This is because the light emission intensity is not uniform due to the influence of the shape of the light emitting element, the electrode provided in the light emitting element, the configuration of each semiconductor layer, or the like. Therefore, as shown in FIG. 3, when the focal point of the light reflecting portion 102 of the translucent member 1 is provided at the center of the first light emitting surface 201 of the light emitting element, from the center of the second light emitting surface 202 at the point p. Where β is the shift angle of light emitted from the center of the second light emitting surface 202 and reflected at the point p and emitted from the light emitting portion 103, β = nα (n is The refractive index of the translucent member). That is, the light from the light emitting portion away from the center of the first light emitting surface 201 of the light emitting element is difficult to control in the radiation direction, and further, the refractive index of the light transmissive member 1 is related. It becomes difficult to obtain parallel light when extracted from the sexual member 1 to the outside.

  Therefore, in the present invention, a light reflecting portion focused on a portion with high emission intensity other than the central portion of the first light emitting surface 201 of the light emitting element according to the distribution of the emission intensity of the light emitting element used in the light emitting device. 102 is formed. By adopting such a form, it becomes possible to control the light according to the light distribution characteristics of the light emitting element 2 without newly adding a constituent member, and desired outgoing light such as parallel light can be obtained.

  Accordingly, in the present invention, in the translucent member 1, the lens portion 101 having the first focal point at the center of the first light emitting surface 201 of the light emitting element, and the portion other than the center of the light emitting surface of the light emitting element, particularly the second A light reflecting portion 102 having a second focal point on the light emitting surface 202 and a light emitting portion 103 that emits reflected light reflected by the light reflecting portion 102 out of light from the light emitting element 2. . With such a configuration, the light from the first light emitting surface 201 out of the light from the light emitting element 2 can be controlled by the lens unit 101 to emit parallel light in a desired direction. Further, the light from the second light emitting surface 202 is reflected by the light reflecting portion 102 to be parallel light, and further, the parallel light can be emitted from the light emitting portion 103 in a desired direction. Accordingly, since the light is converged by the medium (lens, reflecting surface, etc.) having different focal positions, the light from the portion with high emission intensity in the light emitting element 2 can be emitted in a desired direction with high light collection efficiency. In the present specification, light emitted from the light emitting element 2 is referred to as direct light, and light whose direct light is reflected by the light reflecting portion 102 and the traveling direction is changed is referred to as reflected light. Hereinafter, each component of the light emitting device according to the present invention will be described.

(Light emitting element)
In the present invention, the light-emitting element to be used is not particularly limited as long as it has a pair of positive and negative electrodes on the same surface side and can emit a part of light emission from the breaking end face. Examples of the stacked structure of the light emitting element include a homostructure, a heterostructure, or a double heterostructure having a MIS junction, a PI junction, a PN junction, and the like. Various emission wavelengths can be selected depending on the material of the semiconductor layer and the degree of mixed crystal. In addition, a single quantum well structure or a multiple quantum well structure in which the semiconductor active layer is formed in a thin film in which a quantum effect is generated can be used.

  When a gallium nitride compound semiconductor is used, a material such as sapphire, spinel, SiC, Si, ZnO or the like is preferably used for the semiconductor substrate. In order to form a gallium nitride compound semiconductor with good crystallinity with high productivity, it is preferable to use a sapphire substrate. A gallium nitride compound semiconductor can be formed on the sapphire substrate by MOCVD or the like. A buffer layer of GaN, AlN, GaAlN or the like is formed on the sapphire substrate, and a gallium nitride compound semiconductor having a pn junction is formed thereon.

  As an example of a light emitting device having a pn junction using a gallium nitride compound semiconductor, a first contact layer formed of n-type gallium nitride and a first cladding layer formed of n-type aluminum nitride / gallium on a buffer layer And a double heterostructure in which an active layer formed of indium gallium nitride, a second cladding layer formed of p-type aluminum nitride / gallium, and a second contact layer formed of p-type gallium nitride are sequentially stacked. The gallium nitride compound semiconductor exhibits n-type conductivity without being doped with impurities. When forming a desired n-type gallium nitride compound semiconductor such as to improve luminous efficiency, it is preferable to appropriately introduce Si, Ge, Se, Te, C, etc. as an n-type dopant. On the other hand, when forming a p-type gallium nitride compound semiconductor, p-type dopants such as Zn, Mg, Be, Ca, Sr, and Ba are doped. Since the gallium nitride compound semiconductor is difficult to be p-type only by being doped with a p-type dopant, it is preferable to reduce the resistance by heating in a furnace or plasma irradiation after the introduction of the p-type dopant. After the electrodes are formed, a light emitting element made of a gallium nitride compound semiconductor can be formed by cutting the semiconductor wafer into chips.

  The light-emitting element obtained in this manner has high light intensity in the visible region, while light generated in the active layer repeats propagation inside the light-emitting element, so that the light-emitting element is confined in the light-emitting element. From the light emitting surface, it becomes relatively difficult for light to be emitted, and the light emission intensity from the end surface of the light emitting element becomes high. Especially when an active layer containing indium with a relatively small band gap is sandwiched between clad layers containing aluminum with a relatively large band gap, such as a light-emitting device whose active layer is made of a gallium nitride compound semiconductor containing indium. Become. In addition, light that propagates without being transmitted also occurs at the interface between the electrode formed on the light-emitting element and the element and the interface between the different substrates such as sapphire, and light emission from the end face tends to be further promoted. FIG. 17 shows a graph of the light emission intensity of the light emitting element made of such a semiconductor material. FIG. 17 shows the measurement of the light emitting element placed with the electrode formation surface side up, and the relative intensity is shown with 1.0 being the highest emission intensity portion. Assuming that the central axis of the first light emitting surface of the light emitting element is 0 °, the distance increases from the center of the light emitting element, and the light emission intensity peaks at around 45 ° and 75 °, and at around 110 °. It has the highest emission intensity.

  The light emitting element 2 used in the present invention can be electrically connected to an external electrode by being placed on the mounting substrate 3 on which the wiring pattern 8 is formed or on the lead frame 10. In this case, one light emitting element 2 may be used and mounted on the mounting substrate 3 or the like, or a plurality of light emitting elements 2 may be used, and can be determined as appropriate according to the intended use. Although there is no limitation on the arrangement method, the light emitting area and light emission intensity can be increased by arranging adjacent side surfaces (second light emitting surfaces) of each element in parallel in a grid pattern. Moreover, it can be set as the light-emitting device which has desired directivity by the juxtaposition method, such as arrange | positioning so that it may become long in one direction, and making it a rectangular light source. Of the light emitting devices thus obtained, white light can be obtained by combining light emitting devices that emit red, green, and blue light and using them in parallel.

  Furthermore, it is also possible to obtain various color mixture lights such as white light with good color rendering by alternately arranging light emitting elements having different emission colors. In such a case, the color mixing property can be improved by adjusting the order and height in consideration of the emission color of each light emitting element. In addition, when adjusting the height of each light emitting element, the mounting substrate can be formed in a step shape so that light emission is not blocked and light emission is blocked, thereby improving light extraction efficiency. In the light-emitting element 2 used in the embodiment of the present invention, the fluorescent material is applied to the light-emitting surface 201 (first light-emitting surface) and the side surface 202 (second light-emitting surface) of the light-emitting element, or the fluorescent material is applied to the semiconductor layer. It is also possible to obtain various emission colors by combining the light from the light emitting element and the light by the excitation light of the fluorescent material, for example, by mixing.

  In the present invention, the translucent member 1 may contain a pigment made of an inorganic substance or an organic substance. Thus, when a pigment is contained in the translucent member 1, a specific wavelength can be cut, and only light having a desired wavelength can be emitted to the outside due to the effect of the color filter using such a pigment. It becomes possible. Further, the blue light from the light emitting element 2 can be used only to excite a phosphor material, such as a nitride phosphor or a YAG phosphor, and a filter made of pigment can be used so that the blue light is not emitted to the outside. .

(Fluorescent substance)
In addition, the light emitting element used in the present invention is obtained by applying a fluorescent material to the first light emitting surface 201 and the second light emitting surface 202 of the light emitting element, printing, or adding a fluorescent material to the layer. Various emission colors can be obtained by a combination of light and light by excitation light of a fluorescent substance. In such a case, the phosphor layer formed on the first light emitting surface 201 of the light emitting element and the phosphor layer formed on the second light emitting surface 202 of the light emitting element have substantially the same thickness. Thus, uniform color mixture light can be obtained from the entire light emitting element 2. Further, the fluorescent substance used in the present invention may be mixed in the resin when the entire surface of the light emitting element 2 is previously coated with a resin or the like. In the present specification, the members containing the fluorescent material may be collectively referred to as wavelength conversion members.

The phosphor used in the present invention absorbs part of visible light and ultraviolet light emitted from the light emitting element 2 and emits light having a wavelength different from the wavelength of the absorbed light. Such a phosphor is a phosphor that emits light converted in wavelength by being excited by light emitted from at least a semiconductor light emitting layer of a light emitting element, and is contained in a wavelength conversion member together with a binder for fixing the phosphor. Is done. Further, in the present invention, a phosphor that is excited by ultraviolet light and generates light of a predetermined color can be used as a phosphor. As a specific example, for example,
(1) Ca ₁₀ (PO ₄ ) ₆ FCl: Sb, Mn
(2) M ₅ (PO ₄ ) ₃ Cl: Eu (where M is at least one selected from Sr, Ca, Ba, Mg)
(3) BaMg ₂ Al ₁₆ O ₂₇ : Eu
(4) BaMg ₂ Al ₁₆ O ₂₇ : Eu, Mn
(5) 3.5MgO.0.5MgF ₂ .GeO ₂ : Mn
(6) Y ₂ O ₂ S: Eu
(7) Mg ₆ As ₂ O ₁₁ : Mn
(8) Sr ₄ Al ₁₄ O ₂₅ : Eu
(9) (Zn, Cd) S: Cu
(10) SrAl ₂ O ₄ : Eu
(11) Ca ₁₀ (PO ₄ ) ₆ ClBr: Mn, Eu
(12) Zn ₂ GeO ₄ : Mn
(13) Gd ₂ O ₂ S: Eu, (14) La ₂ O ₂ S: Eu, and the like.

  In addition, these phosphors may be used alone in a single-layer wavelength conversion member, or may be used as a mixture. Furthermore, they may be used alone or in combination in a wavelength conversion member in which two or more layers are laminated.

  When the light from the light emitting element and the light emitted from the phosphor are in a complementary color relationship or the like, white mixed color light can be emitted by mixing each light. Specifically, the light emitted from the light emitting element and the phosphor light excited and emitted thereby correspond to the three primary colors of light (red, green, and blue), or the blue light emitted from the light emitting element. And yellow light of a phosphor that is excited to emit light.

  The emission color of the light-emitting device can be adjusted by variously adjusting the ratio between the phosphor and various materials such as glass and inorganic members such as glass, the settling time of the phosphor, and the shape of the phosphor. By selecting the emission wavelength, it is possible to provide an arbitrary white color tone such as a light bulb color.

Specific phosphors include cadmium zinc sulfide activated with copper and yttrium / aluminum / garnet phosphor (hereinafter referred to as “YAG phosphor”) activated with cerium. In particular, at the time of high luminance and long-term use _{(Re 1-x Sm x)} 3 (Al 1-y Ga y) 5 O 12: Ce (0 ≦ x <1,0 ≦ y ≦ 1, where, Re Is at least one element selected from the group consisting of Y, Gd, and La). _{(Re 1-x Sm x)} 3 (Al 1-y Ga y) 5 O 12: Ce phosphor, for garnet structure, heat, resistant to light and moisture, the peak of the excitation spectrum can be like in the vicinity of 470nm Can do. In addition, the emission peak is in the vicinity of 530 nm, and a broad emission spectrum that extends to 720 nm can be provided.

In the light emitting device of the present invention, the phosphor may be a mixture of two or more phosphors. That, Al, Ga, Y, the content of La and Gd and Sm are two or more kinds of _{(Re 1-x Sm x)} 3 (Al 1-y Ga y) 5 O 12: by mixing Ce phosphor RGB wavelength components can be increased. At present, there are variations in the emission wavelength of the semiconductor light emitting device, so that it is possible to obtain a desired white mixed color light by mixing and adjusting two or more kinds of phosphors. Specifically, by adjusting the amount of phosphors having different chromaticity points in accordance with the emission wavelength of the light emitting element, the arbitrary points on the chromaticity diagram connected between the phosphors and the light emitting element are caused to emit light. be able to. Such a phosphor can be dispersed in a gas phase or a liquid phase and released uniformly. The phosphor in the gas phase or liquid phase is precipitated by its own weight. In particular, in a liquid phase, a layer having a phosphor with higher uniformity can be formed by allowing the suspension to stand. A desired amount of phosphor can be formed by repeating a plurality of times as desired.

  Two or more kinds of phosphors formed as described above may be present in a single-layer wavelength conversion member on the surface of the light-emitting device, or one or two of each of the two-layer wavelength conversion member. There may be more than one type. In this way, white light can be obtained by mixing colors from different types of phosphors. In this case, it is preferable that the average particle diameters and shapes of the phosphors are similar in order to better mix the light emitted from the phosphors and reduce color unevenness. Here, in the present invention, the particle size of the phosphor is a value obtained by a volume-based particle size distribution curve, and the volume-based particle size distribution curve can be obtained by measuring the particle size distribution of the phosphor by a laser diffraction / scattering method. Is. Specifically, in an environment where the temperature is 25 ° C. and the humidity is 70%, the phosphor is dispersed in a sodium hexametaphosphate aqueous solution having a concentration of 0.05%, and a laser diffraction particle size distribution analyzer (SALD-2000A) It was obtained by measuring in a particle size range of 0.03 μm to 700 μm.

  The phosphor used in the present embodiment is a combination of an aluminum garnet phosphor typified by a YAG phosphor and a phosphor capable of emitting red light, particularly a nitride phosphor. Can also be used. These YAG phosphors and nitride phosphors may be mixed and contained in the wavelength conversion member, or may be separately contained in the wavelength conversion member composed of a plurality of layers.

  Examples of the fluorescent substance that can be used in the present invention include a photoluminescence phosphor that emits light by being excited by an emission wavelength emitted from a light emitting element. Specific examples include YAG (Y2O3 · 5 / 3Al2O3) -based phosphors such as YAG: Ce, which are phosphors capable of emitting yellow light by blue light emission from a gallium nitride compound semiconductor. In the present invention, the YAG-based phosphor is particularly interpreted in a broad sense, and is substituted with at least one element selected from Y, Lu, Sc, La, Gd and Sm, or a part or all of aluminum is replaced. , And a phosphor containing a fluorescent action that substitutes with either or both of Ga and In.

  Similarly, phosphors capable of emitting red light by blue light emission include nitrogen-containing Ca—Al—Si—N oxynitride fluorescent glass activated by Eu and / or Cr. Note that the peak of the emission spectrum can be continuously shifted from 575 nm to 690 nm by increasing or decreasing the nitrogen content of the Ca—Al—Si—N-based oxynitride fluorescent glass activated with Eu and / or Cr. it can. Therefore, by combining light from a gallium nitride compound semiconductor containing GaN or InGaN doped with impurities such as Mg and Zn and light of a phosphor of about 580 nm, white light similar to that of a YAG phosphor is obtained. Can be obtained.

(Translucent member)
The translucent member 1 used in the present invention includes a lens part 101 having a focal point at the center of the light emitting surface 201 of the light emitting element 2, a light reflecting part 102 having a focal point at a portion where the light emission intensity of the light emitting element is high, and light reflection. The light emitting unit 103 emits the light reflected by the unit 102 and parallel to each other to the outside.
The material used for the translucent member 1 of the present invention is not particularly limited as long as it is a material that can emit light from the light emitting element 2 to the outside, such as epoxy resin, hard silicone, acrylic, polycarbonate, and the like. Among these materials, when a light-transmitting material having a relatively high refractive index is used, light can be efficiently extracted to the outside of the light-transmitting member 1.

  The light reflecting portion 102 used in the present invention is preferably a parabolic surface having a focal point on the second light emitting surface 202 of the light emitting element. In this way, by arranging the lens unit 101 and the light reflecting unit 102 so as to have different focal points in the relatively high emission intensity portions, the light collection efficiency of the light from the light emitting element 2 can be increased, Light can be efficiently controlled in a desired radiation direction. That is, with such a configuration, the light collection efficiency of the light from the light emitting element 2 can be increased, so that parallel light with high luminance can be obtained more efficiently.

  The lens unit 101 and the light reflecting unit 102 according to the present invention are appropriately set according to the light distribution characteristics of the light emitting element 2. For example, in the case of using the element having the light distribution characteristic shown in the graph of FIG. 17, the distance from the central axis (0 °) of the first light emitting surface 201 of the light emitting element is more specifically, around 45 ° and 75 °. It has a peak with high emission intensity in the vicinity, further around 110 ° and the like. Therefore, it is necessary to set the light reflecting portion 102 in order to reflect light from a portion with high emission intensity from the second light emitting surface 202 of the light emitting element from which most of the light is emitted.

  Therefore, in the present invention, the focal point of the lens part 101 of the translucent member is provided on the first light emitting surface 201 of the light emitting element, and the focal point of the light reflecting part 102 of the translucent member is on the side surface of the light emitting element. When provided on the second light emitting surface 202, the light from the first light emitting surface 201 of the light emitting element is controlled by the lens unit 101, and the light from the second light emitting surface 202 of the light emitting element is Since it is controlled by the light reflecting portion 102, light can be efficiently extracted in a desired radiation direction.

  Specifically, as shown in FIG. 4, when the central axis of the light emitting element 2 is 0 °, the light reflecting portion 102 is from 40 ° to around 90 ° (when the axis parallel to the light emitting surface is 0 °). Is preferably provided (from 0 ° to around 50 °) because the light from the second light emitting surface 202 of the light emitting element can be sufficiently received (reflected). Further, it is more preferable that the light reflecting portion 102 is provided in the vicinity of 40 ° to 100 °. Light emitted from the second light emitting surface 202 of the light emitting element has particularly high light emission intensity in the vicinity of 110 °, which is further downward than 90 °. Therefore, if it does in this way, more light can be utilized. Further, by providing the lens portion 101 of the translucent member from 0 ° to around 40 °, the light emitted from the first light emitting surface 201 of the light emitting element can be condensed and extracted to the outside.

  Further, in the light emitting device of the present invention, when the normal direction of the light emitting part is 0 °, the incident angle of the light from the light emitting element to the light emitting part is set in a range larger than 0 ° and smaller than the critical angle. Light emitted from the light emitting element is not reflected by the light emitting portion. When the light emitted from the light emitting element is reflected by the light emitting portion 103 of the translucent member, the light from the light emitting element repeats reflection and propagates within the translucent member depending on the angle at which the light enters. There is. As light is repeatedly reflected in this manner, the light is gradually attenuated, making it difficult to effectively use light emission. Further, only the reflected light from the light reflecting portion 102 is extracted from the light emitting portion 103, and the direct light from the second light emitting surface 202 of the light emitting element is not directly extracted from the light emitting portion 103 to the outside. Therefore, it is possible to prevent the light from the second light emitting surface 202 of the light emitting element from being directly taken out from the light emitting unit 103 without being controlled in the radiation direction by the light reflecting unit 102.

Examples of the method for forming a light emitting device according to an embodiment of the present invention are shown below.
First, the light emitting element 2 is placed on the mounting substrate 3 on which the wiring pattern 8 is formed. The mounting substrate 3 can be made of a metal material or an insulator having good thermal conductivity such as AlN or CuW. The light emitting element 2 may be placed directly on the mounting substrate 3 or may be placed on the mounting substrate 3 via a submount 4 made of AlN, CuW or the like.

  Next, using a mold having a desired shape, epoxy resin, silicone, acrylic, or the like is used as a material, and injected into the mold and cured to obtain a translucent member 1 having a desired shape. Can do. Such a translucent member 1 can be prepared in advance and installed so as to cover the light emitting element 2 placed on the mounting substrate 3 later, or as shown in FIG. It is also possible to integrally mold the lead frame 10 and the translucent member 1. Next, an example is shown below as a method of determining the shape of the translucent member.

  First, when the central axis of the first light emitting surface 201 of the light emitting element is set to 0 °, the light emitting portion 103 is set around 40 ° with the center of the second light emitting surface 202 of the light emitting element as a reference point. To do. Further, the center of the second light emitting surface 202 of the light emitting element is set as a reference point so that one end a of the light reflecting portion 102 is arranged in the 100 ° direction. At this time, one end portion a of the light reflecting portion 102 is determined in accordance with a predetermined size of the light emitting device as shown in FIG. One end a of the light reflecting portion 102 is connected to the mounting substrate 3 and can be set by adjusting the height of the submount 4. A curvature having a focal point at the center of the second light emitting surface 202 of the light emitting element from one end a of the light reflecting portion 102 to a portion where the other end b of the light reflecting portion 102 and the light emitting portion 103 are in contact with each other. A paraboloid consisting of is formed. At this time, the inclination of the paraboloid is set in consideration of the refractive index of the translucent member 1 and the inclination angle of the light emitting portion 103.

  The light emitting unit 103 is set so that at least light from the light emitting element reflected by at least one end a of the light reflecting unit 102 is extracted from the light emitting unit 103 to the outside. Therefore, the light emitting portion 103 is provided up to a portion c where light from one end a of the light reflecting portion 102 enters the light emitting portion 103. Further, the lens unit 101 is set so as to focus on the center of the first light emitting surface 201 of the light emitting element from the portion c.

  The light emitting portion 103 of the translucent member is provided for emitting the light reflected by the light reflecting portion 102 of the translucent member to the outside. In addition, the light emitting unit 103 is formed of a flat surface, and is disposed so as to be parallel to the light emitting direction from the second light emitting surface 202 of the light emitting element, whereby the first light emitting surface 201 of the light emitting element. In addition, direct light from the second light emitting surface 202 of the light emitting element is not incident. Therefore, light extracted outside without being controlled by the lens unit 101 or the light reflecting surface 102, that is, leakage light can be eliminated. In addition, by using the light emitting portion 103 having such a surface, the angle at which the light reflecting portion 102 is provided can be tilted in a more vertical direction, so that the spread of the light reflecting portion 102 of the translucent member can be suppressed. It is also possible to reduce the diameter.

  The light reflecting portion 102 of the translucent member is preferably a parabolic surface because a favorable focus can be provided on the second light emitting surface 202 of the light emitting element. Such a light reflection part 102 needs to consider the refractive index of the translucent resin etc. which are used as a translucent member, and the angle in which the light emission part 103 is provided. That is, the angle of the light reflecting portion 102 is set from the ratio of light refracted when light from the light emitting element enters the air layer from the light emitting portion 103 of the translucent member. By doing in this way, since the light from the light emission part 103 can be radiate | emitted in parallel with the light from the lens part 101 of a translucent member, it also becomes possible to obtain parallel light with high brightness | luminance.

  In addition, it is preferable to deposit a material having a good light reflection efficiency such as Ag or Al on the light reflecting portion 102 of the translucent member or to form the material by sputtering so that light from the light emitting element can be used effectively. However, it is not necessary to form such a light reflecting material over the entire surface of the light reflecting portion, and an effect can be obtained by applying it to a portion of the light reflecting portion where light from the light emitting element is not reflected. In the case shown in FIG. 4, the portion where the light from the light emitting element is not reflected is the portion where the incident angle of the light from the light emitting element is smaller than the critical angle, that is, the light from the light emitting element is substantially normal to the light reflecting portion 102. This is a portion 5 on the mounting substrate side that is incident from the direction. By forming a light reflecting material on at least these portions on the surface of the translucent member 1, it is possible to improve the reflection efficiency of light from the light emitting element and to control light in a desired radiation direction.

  Furthermore, by coating the surface of the light reflecting portion 102 of the translucent member with a material such as acrylic or polycarbonate, handling becomes easy, and peeling of the light reflecting material provided on the surface can be suppressed. it can.

  Furthermore, in order to improve the utilization efficiency of the emitted light from the light emitting element 2, it can be mounted on the mounting substrate 3 via the submount 4. The height of the submount 4 is appropriately determined depending on the size of the light emitting device and the emission angle of light traveling from the light emitting element 2 downward on the mounting substrate side. In the case of using a light-emitting element having a light distribution characteristic as shown in FIG. 17, when the central axis of the first light-emitting surface 201 of the light-emitting element is 0 °, a large amount of light is emitted to around 100 °. For this reason, it is preferable to set the height of the submount 4 so that light traveling in a direction near 100 ° out of light emitted from the substantially central portion of the second light emitting surface 202 of the light emitting element is not reflected by the mounting substrate 3. In addition, since one end portion a of the light reflecting portion can be determined by the height of the submount 4, the diameter of the light emitting device can be reduced.

  The lens portion 101 of the translucent member is disposed so as to have a focal point at the center of the first light emitting surface 201 of the light emitting element, thereby efficiently controlling light from the first light emitting surface 201 of the light emitting element. Can be. Such a lens unit 101 is provided so that at least light from the second light emitting surface 202 of the light emitting element reflected by the light reflecting unit 102 is extracted from the light emitting unit 103 to the outside of the translucent member. That is, after light emitted from the light emitting element in the downward direction (on the mounting substrate side) is reflected by the light reflecting portion 102, the light does not enter the lens portion 101 and is emitted from the light emitting portion 103 in a desired radiation direction. The light emitting unit 103 is provided in the extraction range, and the lens unit 101 is provided outside the light emitting unit 103.

  Moreover, an air layer can be formed by providing the recessed part 6 between the lens part 101 and the light emitting element 2 of a translucent member. When the light-transmitting member is made of a relatively hard material such as acrylic, the light-emitting element expands due to heat from the light-emitting element, which may cause the light-emitting element to peel off or the wire 204 to be disconnected. However, by providing the light-transmitting member with the recess 6 and providing an air layer around the light-emitting element 2, peeling of the light-emitting element and disconnection of the wire 204 can be prevented.

  FIGS. 5A and 5B show a deviation angle from the central axis direction of the light emitting element when the light from the second light emitting surface 202 of the light emitting element enters the point p of the lens portion 101 of the translucent member. Is represented by α and β. In (b), an air layer is provided between the light-emitting element 2 and the translucent member 1, and the size of the light-emitting element 2 is determined by the refractive index difference between the translucent member 1 made of resin and the air layer. It can be seen smaller than the actual one. Therefore, when an air layer is interposed between the light emitting element 2 and the translucent member 1, light that should be incident on the p point from the second light emitting surface 202 of the light emitting element is incident on the p 'point. Therefore, the shift angle of β is smaller than α (α> β), and it is possible to increase the light collection efficiency and obtain high-intensity parallel light.

  Further, when an air layer is provided between the light emitting element 2 and the translucent member 1, light from the light emitting element 2 may be difficult to extract because the refractive index of the light emitting element is higher than that of air. In such a case, the above-mentioned problem is solved by forming a resin layer on the surface of the light emitting element 2. In addition, when a fluorescent material is applied to the surface of the light emitting element 2, the layer made of the wavelength conversion member containing the fluorescent material plays the same role as the above-described resin layer, and the light extraction efficiency from the light emitting element 2 is improved. It can be good.

The above light-emitting device can be used for a lighting device. FIG. 12 is a schematic cross-sectional view of an illuminating device in which the light-emitting device 15 on which the light-emitting elements 2 having different emission colors of red, green, and blue are mounted is juxtaposed in the case 20. As shown in this figure, by bringing the light emitting device into contact with the heat sink, heat generated during light emission can be efficiently guided to the outside, so that the lighting device with good heat dissipation can be obtained. In addition, the light-transmitting cover lens is fixed to the case, so it is possible to form an arbitrary light distribution, prevent dust and dust from entering the case, and improve the reliability of the lighting device. It can also be maintained. As a juxtaposition method of the light emitting devices, a circular arrangement as shown in FIG. 13 or a rectangular arrangement as shown in FIG. 14 can be adopted. Further, it can be arranged in a ring shape as shown in FIG. 15 or in a linear shape as shown in FIG. However, the present invention is not limited to such an example, and can be determined as appropriate according to the shape of the case used, the color or characteristics of the light emitting device, and the like. Further, when the lighting device as shown in these figures is used, a full-color emission color can be reproduced by using a light emission device having at least one set of red, green, and blue emission colors. A light emission color such as white light can be obtained by the mixed color light. As the number of light emitting devices used in the lighting device, the same number of light emitting devices having different light emission colors may be used, but it is also possible to use more light emitting devices having light emission colors with lower luminance than others. is there. By adopting such a form, it is possible to obtain a light emitting device that can mix colors well and can output uniform spot light.
Next, light emitting devices according to examples of the present invention will be described. However, the present invention is not limited to the following.

  6 and 10 are a schematic cross-sectional view and a schematic perspective view of the light emitting device according to the first embodiment. In such a light-emitting device, first, the light-emitting element 2 is placed on the surface of the metal substrate 3 made of Cu via the insulating film 7 on the mounting substrate 3 on which the wiring pattern 8 is formed in advance using Ag paste. Connecting. The light-emitting element 2 is a nitride semiconductor having an active layer made of InGaN formed on a sapphire substrate via a buffer layer, and a pair of electrodes (not shown) is formed on the semiconductor formed on the sapphire substrate. Has been. The electrode formed on such a light emitting element and the wiring pattern 8 are bonded by a wire 204 to enable conduction. Next, an epoxy resin is injected into a concave portion of the casting case corresponding to a preset shape included in the translucent member 1 of the light emitting device and cured. The translucent member 1 thus obtained was positioned by aligning the optical axis with the light emitting element 2 on the mounting substrate 3 and fixed on the mounting substrate 3 with screws 9. Furthermore, when the central axis of the first light emitting surface of the light emitting element was 0 °, an Al material was formed by sputtering so as to cover 80-100 ° of the surface of the light transmissive member 1 of the light emitting device.

  The light emitting device thus obtained was able to obtain parallel light with good controllability. In addition, the light-transmitting member is provided with a recess 6, and the light-emitting element 2 and the light-transmitting member 1 can be set to be smaller than the actual size by passing the air layer between the light-emitting element 2 and the light-transmitting member 1. Since the angle can be reduced and output from the translucent member 1 to the outside, a light-emitting device with high light collection efficiency can be obtained.

  7 and 11 are a schematic sectional view and a schematic perspective view of the light emitting device according to the second embodiment. In such a light emitting device, first, a lead frame 10 in a state in which a pair of lead frames are connected in parallel with each other at a tie bar portion by punching a metal plate of iron-containing copper is formed. One of the lead frames functions as a mount lead in which a cup is formed so that the light emitting element is disposed, and the other is electrically connected to one of the electrodes (not shown) of the light emitting element by a wire 204. Functions as an inner lead to be connected. Next, the light emitting element 2 made of the same nitride semiconductor as that used in Example 1 is placed on the tip of the mount lead, which is one lead frame, and fixed with an adhesive. Further, each electrode of the light emitting element 2 and each lead frame 10 are bonded by a wire 204 and are electrically connected. Next, an epoxy resin was injected into a concave portion of the casting case corresponding to a preset shape included in the translucent member 1 of the light emitting device and cured. Further, a predetermined portion of the tie bar portion was cut and separated from the casting case to form a light emitting device having the shape of the translucent member 1 shown in FIG. Further, when the central axis of the first light emitting surface of the light emitting element is set to 0 °, an Al material is formed by sputtering so as to cover the vicinity of 80 to 100 ° of the light transmitting member surface 1 of such a light emitting device. did.

  Even with such a light emitting device, parallel light with high luminance could be obtained as in Example 1.

(Comparative Example 1)
FIG. 8 shows a light emitting device according to a comparative example of the present invention.
A light emitting device having the shape of the translucent member 1 shown in FIG. Such a light emitting device according to Comparative Example 1 is set so that the direct light emitted from the light emitting element 2 is reflected by the reflecting portion, and then the reflected light is perpendicularly incident on the light emitting portion. In addition, since the light amount equivalent to that of the first embodiment is reflected by the reflecting portion, the height in the emission direction of the translucent member 1 in the light emitting device is higher than that of the first embodiment. Therefore, the distance that the light from the light emitting element 2 passes through the translucent member 1 is longer than that in the first embodiment, so that the amount of light attenuated and extracted to the outside of the translucent member 1 is reduced. Further, as shown in FIG. 9, there is a region where light cannot be controlled, and it is difficult to efficiently control in the irradiation direction. Therefore, the light-emitting device according to Comparative Example 1 is not only difficult to handle due to an increase in the amount of resin used in the translucent member 1 as well as not being able to obtain spot light with a high luminance as compared with Example 1. It becomes a light emitting device.

  The present invention can be used as a spot light source with a high light collection rate for a projector, a light source for a projector, a light source for a head-up display, a vehicle illumination, and the like.

It is typical sectional drawing of the light-emitting device which concerns on one Embodiment of this invention. It is typical sectional drawing of the light-emitting device which concerns on one Embodiment of this invention. It is typical sectional drawing of the light-emitting device which concerns on one Embodiment of this invention. It is typical sectional drawing of the light-emitting device which concerns on one Embodiment of this invention. (A) It is typical sectional drawing of the light-emitting device which concerns on one Embodiment of this invention. (B) It is typical sectional drawing of the light-emitting device which concerns on one Embodiment of this invention. It is typical sectional drawing of the light-emitting device which concerns on the Example of this invention. It is typical sectional drawing of the light-emitting device which concerns on the Example of this invention. It is typical sectional drawing of the light-emitting device which concerns on the comparative example of this invention. It is typical sectional drawing of the light-emitting device which concerns on the comparative example of this invention. It is a typical perspective view of the light-emitting device which concerns on the Example of this invention. It is a typical perspective view of the light-emitting device which concerns on the Example of this invention. It is typical sectional drawing of the illuminating device which concerns on one Embodiment of this invention. It is a typical top view of the illuminating device which concerns on one Embodiment of this invention. It is a typical top view of the illuminating device which concerns on one Embodiment of this invention. It is a typical top view of the illuminating device which concerns on one Embodiment of this invention. It is a typical top view of the illuminating device which concerns on one Embodiment of this invention. It is a graph which shows the light distribution characteristic of the light emitting element (die) used in the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 .. Translucent member 101 .. Lens part 102 .. Light reflection part 103 ... Light emitting part 2 .... Light emitting element 201 ... First light emitting surface 202 ... Second light emitting surface 204 ... Wire 3・ ・ Mounting board 4 ・ ・ Submount 5 ・ ・ Light reflection material 6 ・ ・ Translucent member recess 7 ・ ・ Insulating film 8 ・ ・ Wiring pattern 9 ・ ・ Screw clamp 10 ・ ・ Lead frame 15 ・ ・Light-emitting device 20 ・ ・ Case 21 ・ ・ Cover 22 ・ ・ Heat sink

Claims (10)

A light-emitting device comprising: a light-emitting element; and a translucent member that is provided to face the first light-emitting surface and the second light-emitting surface of the light-emitting element and emits light from the light-emitting element in a radiation direction. And
The light emitting element has a plurality of light emitting portions on the first light emitting surface and the second light emitting surface, and the translucent member includes a lens portion that emits direct light from the light emitting element, and at least from the light emitting element. A light reflecting portion that reflects the direct light and a light emitting portion that emits at least the reflected light reflected by the light reflecting portion, wherein the lens portion and the light reflecting portion are a plurality of light emitting portions of the light emitting element. Of these, a light emitting device characterized in that each has a focus on a different light emitting portion. The lens has a first focal point in the center of a first light emitting surface of the light emitting element, and the light reflecting portion has a second focal point on a second light emitting surface of the light emitting element. Item 4. The light emitting device according to Item 1. The light emitting device according to claim 1, wherein the light emitting unit emits only the light reflected by the light reflecting unit out of the light from the light emitting element. The light-emitting device according to claim 1, wherein the light reflecting portion includes a parabolic surface. The light emitting device according to claim 1, wherein the light emitting portion is a flat surface. The light from the light emitting element reflected by the light reflecting portion is set in a range where an incident angle with respect to the light emitting portion is larger than 0 ° and smaller than a critical angle. Light emitting device. The light emitting device according to claim 1, wherein the translucent member is adjacent to the light emitting element via an air layer. The light emitting device according to claim 1, wherein a light reflecting material is formed on an outer surface of the light reflecting portion. The light emitting device according to claim 1, wherein the light emitting element is mounted via a submount. The light emitting device according to claim 1, wherein the light emitting element is made of a gallium nitride compound semiconductor.

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