WO2008020575A1 - Semiconductor light emitting device - Google Patents

Abstract

[PROBLEMS] To provide a semiconductor light emitting device which can be easily manufactured and has stable light emitting characteristics. [MEANS FOR SOLVING PROBLEMS] A semiconductor light emitting device is provided with a blue LED chip (1) and a resin sealing section (4) for sealing the blue LED chip (1) with a resin. In the semiconductor light emitting device, phosphor (12) having fine particles is uniformly dispersed in the sealing resin (11). The phosphor (12) is formed by adhering blue light scattering fine particles (12b) on an outer surface of a particulate phosphor (12a). The blue light scattering fine particle has a particle diameter larger than the wavelength of blue light emitted from the blue LED Chip (1), and a refraction index equivalent to or smaller than that of the phosphor (12a) but is larger than that of the sealing resin (11). One or more layers of the blue light scattering fine particles (12b) are adhered on the external surface of the phosphor (12a). As the sealing resin (11), an epoxy resin or a silicone resin can be used, and as the phosphor (12a), a YAG phosphor can be used and as the blue light scattering particles (12b), alumina or silica can be used.

Description

 Specification

 Semiconductor light emitting device

 Technical field

 [0001] The present invention excites the phosphor dispersed in the resin sealing portion by the emitted light of the light emitting diode (hereinafter, abbreviated as "LED" in the present specification), and the emitted light of the LED Related to semiconductor light-emitting devices that emit mixed light of phosphor and excitation light from a phosphor to the outside

 [0002] A white LED is a blue LED that emits blue light, a resin sealing portion that seals the periphery of the blue LED, and a blue light that is dispersed within the resin sealing portion and emitted from the blue LED. It is composed of a phosphor that absorbs yellow light that is complementary to red and green and excites yellow light. The resin mixes blue light emitted from the blue LED and yellow light excited by the phosphor. The light is emitted from the sealing portion to the outside. As the phosphor, a particulate YAG having a particle diameter of about 5 111 to 1 m is used, and an epoxy resin, a silicone resin, or the like is used as a sealing resin constituting the resin sealing portion (for example, a patent) See references 1 and 2.) Patent Document 1: Japanese Unexamined Patent Publication No. 2005-135983

 Patent Document 2: Japanese Patent Laid-Open No. 2005-333097

 Disclosure of the invention

 Problems to be solved by the invention

 By the way, in order to produce an efficient white LED, blue light emitted from a blue LED is appropriately absorbed by a phosphor, and yellow light having a complementary color relationship between red and green is excited with high efficiency. It is important that blue light and yellow light are mixed uniformly.

[0004] In order to uniformly mix the blue light emitted from the blue LED and the yellow light that is the excitation light of the phosphor, it is necessary to match the light distribution of each color light, especially from the blue LED. Force that needs blue light to be Lambert light distribution To make blue light Lambert light distribution, it is necessary to sufficiently scatter blue light in the resin sealing part, and in the resin sealing part There is a need to increase the phosphor content. In the resin sealing part When the phosphor content is increased, the amount of blue light absorbed increases and the amount of yellow light increases, resulting in a problem that the color coordinates of the emitted light shift. In addition, since the viscosity of the sealing resin containing the phosphor is increased, if the sealing resin is difficult to handle, the dispersion of the phosphor in the resin sealing portion that is connected with the glue becomes non-uniform, resulting in a color change. There is also a problem that unevenness is likely to occur.

 [0005] In the above description, all semiconductor light emitting elements having the power LED described by taking the white LED as an example, the phosphor excited by the emitted light of the LED, and the resin sealing portion for dispersing the phosphor Have the same disadvantages.

 [0006] The present invention has been made to solve the problems of the conventional technology, and the purpose thereof is to provide a semiconductor light emitting device that is easy to manufacture and has stable light emission characteristics. To do · ο.

 Means for solving the problem

 [0007] In order to solve the above-mentioned problem, the present invention firstly, an LED, a resin sealing portion that seals the periphery of the LED, and the light emitted from the LED dispersed in the resin sealing portion. A semiconductor light emitting device that has a phosphor that excites excitation light having a wavelength different from that of the emitted light, and emits mixed light of the emitted light and the excitation light from the resin sealing portion to the outside In the periphery of the phosphor, the refractive index whose particle diameter is smaller than the wavelength of the emitted light is the same as or smaller than the refractive index of the phosphor and larger than the refractive index of the resin sealing portion. The configuration is such that fine particles for scatter of radiation are attached.

[0008] Around the phosphor, the refractive index whose particle diameter is smaller than the wavelength of the emitted light of the LED is the same as or smaller than the refractive index of the phosphor and larger than the refractive index of the resin sealing portion. Adhering fine particles for scattering of radiated light allows the radiated light of the LED to be sufficiently Rayleigh scattered within the resin-sealed part, so that the incident efficiency of the radiated light of the LED on the phosphor can be increased. Also, since the light distribution from the LED and the excitation light of the phosphor can be matched, each of these lights can be mixed uniformly. In addition, LED radiation can be sufficiently scattered within the resin-encapsulated part without increasing the phosphor content in the resin-encapsulated part, making it easy to handle the encapsulating resin containing the phosphor. In addition, the dispersion of the phosphor in the sealing resin can be made uniform. [0009] In addition, according to the present invention, secondly, in the semiconductor light emitting device having the first configuration, the fine particles have a diameter in a range of S40 to 100 nm.

[0010] Since the particle diameter of the fine particles is small! /, The blue light is easily scattered! /, The present configuration can improve the efficiency of the blue light scattering.

[0011] Further, according to the third aspect of the present invention, in the semiconductor light emitting device having the first or second configuration, the fine particles are fine particles of silica or alumina, and the resin sealing portion is an epoxy resin or The composition is made of silicone resin.

[0012] Silica and alumina fine particles have light scattering properties and are chemically stable.

Particularly excellent as light-scattering particles contained in the sealing resin. Epoxy resins and silicone resins are excellent in translucency and have a lower refractive index than silica or alumina.

In particular, it is excellent as a sealing resin constituting the resin sealing portion.

 The invention's effect

 [0013] In the present invention, around the phosphor dispersed in the resin sealing portion, the refractive index at which the particle diameter is smaller than the wavelength of the emitted light of the LED is the same as or smaller than the refractive index of the phosphor. Since the particles for scattering scattered light larger than the refractive index of the resin-encapsulated part are attached, the emitted light from the LED is sufficiently contained in the resin-encapsulated part without increasing the phosphor content in the resin-encapsulated part. Can make Rayleigh tongue L to force S. Therefore, the in-plane distribution of color coordinates of the semiconductor light emitting device having the LED, the phosphor excited by the emitted light of the LED, and the resin sealing portion that disperses the phosphor can be stabilized, and the sealing can be performed. Resin handling can be facilitated, and the manufacture of this type of semiconductor light emitting device can be facilitated.

 BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the semiconductor light emitting device according to the present invention will be described with reference to FIGS. 1 to 5. FIG. 1 is a configuration diagram of the semiconductor light emitting device according to the embodiment, FIG. 2 is an explanatory view showing a dispersion state of the phosphor with fine particles in the resin sealing portion, and FIG. 3 is a phosphor with fine particles dispersed in the resin sealing portion. FIG. 4 is a graph showing a comparison between the emission light spectrum of the semiconductor light emitting device according to the conventional example and the emission light spectrum of the semiconductor light emitting device according to the embodiment, and FIG. 5 is a graph of the semiconductor light emitting device according to the conventional example. FIG. 5 is a graph showing a comparison between in-plane distribution of color coordinates and in-plane distribution of color coordinates of the semiconductor light emitting device according to the embodiment. [0015] As shown in FIG. 1, the semiconductor light emitting device of this example is installed in the cup 2 with a blue LED chip 1, an adhesive leg 3 having a cup 2 for installing the blue LED chip 1. The resin sealing part 4 that seals the periphery of the blue LED chip 1, the leg 6 that is placed opposite to the adhesive leg 3 via the insulator 5, and the terminal part of the LED chip 1 and each leg 3, 6 It consists of conducting wires 7 and 8.

 As shown in FIG. 2, the resin sealing portion 4 is formed by uniformly dispersing the phosphor 12 with fine particles in the sealing resin 11. The phosphor 12 with fine particles has a refractive index smaller than the wavelength of the blue light (460 nm to 470 nm) emitted from the blue LED chip 1 on the outer surface of the phosphor 12a formed in a particle shape. The blue light scattering fine particles 12b that are equal to or smaller than the refractive index of the sealing resin 11 and larger than the refractive index of the sealing resin 11 are attached. The smaller the particle size of the blue light scattering fine particles 12b, the easier it is to scatter blue light. Therefore, it is preferably adjusted to 1/4 or less of the wavelength of blue light, more preferably 1/10 or less of the wavelength of blue light. The As shown in Fig. 3, the adhesion of blue light scattering fine particles 12b to phosphor 12a is performed on the outer surface of phosphor 12a as shown in Fig. 3 using a mechanical fine particle composite device NC-LAB-P manufactured by Hosokawa Micron. It can be made to adhere densely. The number of layers of the blue light scattering fine particles 12b should be about 2 to 5 on average in consideration of the balance between the degree of blue light scattering and the degree of blue light incident on the phosphor 12a. desirable.

 [0017] As the sealing resin 11 constituting the resin sealing portion 4, an epoxy resin or a silicone resin can be used. In this example, a silicone resin having a refractive index of 1.41 was used. As the phosphor 12a, a YAG phosphor having an average particle diameter of 5 μm to 10 μm was used.

 Since the refractive index of the YAG phosphor is approximately 1.8, in this phosphor, alumina particles or silica particles can be used as the blue light scattering fine particles 12b. In this example, an average of three layers of silica fine particles having an average particle diameter of 80 nm (average refractive index = 1.50) were deposited. A phosphor with 30 vol% of the fine particles adhered thereto was mixed in a silicone resin, and the LED was sealed and compared with the case where fine particles were not adhered.

 [0018] The other parts of the semiconductor light emitting device are well-known matters and are not the gist of the present invention, so the description is omitted.

[0019] The semiconductor light-emitting device of the present example has particles around the phosphor 12a dispersed in the sealing resin 11. Blue light scattering with a refractive index smaller than the wavelength of the blue light emitted from the LED chip 1 is the same as or smaller than the refractive index of the phosphor 12a and larger than the refractive index of the sealing resin 11 Since the fine particles 12b are attached, the blue light emitted from the blue LED chip 1 can be sufficiently Rayleigh scattered in the resin sealing portion 4 and the efficiency of blue light incident on the phosphor 12a can be increased. . In addition, since the blue light is sufficiently Rayleigh scattered, the light distribution of the blue light emitted from the blue LED chip 1 and the yellow light, which is the excitation light of the phosphor 12a, can be matched. Can be mixed uniformly. Further, since the blue light can be sufficiently Rayleigh scattered in the resin sealing portion 4 without increasing the content of the phosphor 12a in the resin sealing portion 4, the sealing resin 11 containing the phosphor 12a 11 The viscosity of the resin can be kept low, facilitating the handling thereof, and the dispersion of the phosphor in the sealing resin 11 can be made uniform. Therefore, the semiconductor light emitting device of this example is easy to manufacture and can emit white light with stable in-plane distribution of color coordinates.

That is, as shown in FIG. 4, the semiconductor light emitting device according to the embodiment has a shorter wavelength component (blue light) due to a lower intensity than the semiconductor light emitting device according to the conventional example. It can be seen that the intensity of the component (yellow light) has increased, and the incidence efficiency of the blue light emitted from the blue LED chip 1 on the phosphor 12a is increased. Further, as shown in FIG. 5, the semiconductor light emitting device according to the conventional example has about 0 in-plane change of the color coordinate in both the x direction and the y direction with x = 0.31 and y = 0.32. In contrast, in the semiconductor light emitting device according to the embodiment, the in-plane change of the color coordinate in the x direction and the y direction centered on x = 0.31 and y = 0.32 is 0.00. As shown below, the blue light emitted from the blue LED chip 1 and the yellow light that is the excitation light of the phosphor 12a match and the blue light and yellow light are easily mixed! /, S force,

In the above-described embodiment, the semiconductor light emitting element that includes the blue LED chip 1 and emits white light has been described as an example. However, the gist of the present invention is not limited to this, and the LED radiation is not limited thereto. Applicable to all semiconductor light emitting devices that excite phosphors dispersed in resin-sealed parts with light and emit mixed light of LED radiation and phosphor excitation light from resin-sealed parts to the outside Can do.

Brief Description of Drawings FIG. 1 is a configuration diagram of a semiconductor light emitting device according to an embodiment.

 FIG. 2 is an explanatory view showing a dispersion state of a phosphor with fine particles in a resin sealing portion.

 FIG. 3 is a cross-sectional view of a phosphor with fine particles dispersed in a resin sealing portion.

 FIG. 4 is a graph showing a comparison between an emitted light spectrum of a semiconductor light emitting device according to a conventional example and an emitted light spectrum of a semiconductor light emitting device according to an embodiment.

 FIG. 5 is a graph showing a comparison between an in-plane distribution of color coordinates of a semiconductor light emitting device according to a conventional example and an in-plane distribution of color coordinates of a semiconductor light emitting device according to an embodiment.

 Explanation of symbols

[0023] 1 Blue LED chip

 4 Resin sealing part

 11 Sealing resin

 12 Phosphor with fine particles

 12a phosphor

 12b Blue light scattering fine particles

Claims

The scope of the claims  [1] A light emitting diode, a resin sealing portion that seals the periphery of the light emitting diode, and an excitation that is dispersed in the resin sealing portion and absorbs the light emitted from the light emitting diode and has a wavelength different from that of the emitted light In a semiconductor light emitting device that has a phosphor that excites light and emits mixed light of the emitted light and the excitation light to the outside from the resin sealing portion,  Around the phosphor, a refractive index whose particle diameter is smaller than the wavelength of the emitted light is equal to or smaller than the refractive index of the phosphor, and larger than the refractive index of the resin sealing portion. A semiconductor light emitting device, wherein fine particles for scattering light are attached.  [2] The semiconductor light emitting device according to [1], wherein the diameter of the fine particles is in the range of 40 to 100 nm.  3. The semiconductor light emitting device according to claim 1, wherein the fine particles are fine particles of silica or alumina, and the resin sealing portion is made of an epoxy resin or a silicone resin. 4. The semiconductor light emitting device according to claim 2, wherein the fine particles are fine particles of silica or alumina, and the resin sealing portion is made of an epoxy resin or a silicone resin.