JP2005183900A - Light emitting device and lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce luminescent color variation of a light emitting device which emits light whose wavelength is transformed by phosphor particles of three primary colors. <P>SOLUTION: A light emitting device comprises a light emitting element 5 whose luminescence wavelength is 300 to 400 nm, a phosphor particle of La<SB>2</SB>O<SB>2</SB>S:Eu arranged on an optical axis of the light emitting element 5, a phosphor layer 4 constituted by mixing a phosphor particle of ZnS:Cu, Al and a phosphor particle of (BaMgAl)<SB>10</SB>O<SB>12</SB>:Eu into a transparent member. The average particle diameter of each phosphor particle is 1 to 50 μm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a light-emitting diode device, and more particularly to a light-emitting device and a lighting device that emits light emitted from a light-emitting element after wavelength conversion.

  A light-emitting device for accommodating a light-emitting element 105 such as a conventional light-emitting diode (LED) is shown in FIG. As shown in FIG. 2, the light emitting device has a light emitting element 105 mounted in the center of the upper surface, and leads that electrically connect the inside and outside of the light emitting element 105 and the light emitting element storage package (hereinafter also simply referred to as a package). A base 101 made of an insulator on which a wiring conductor (not shown) composed of a terminal, a metallized wiring layer, etc. is formed, and a through hole for adhering and fixing to the upper surface of the base 101 and accommodating the light emitting element 105 in the central portion. It is mainly composed of the formed frame body 102 made of metal, resin, ceramics or the like.

  The substrate 101 is made of an aluminum oxide sintered body (alumina ceramic), an aluminum nitride sintered body, a mullite sintered body, ceramics such as glass ceramics, or a resin such as an epoxy resin. When the substrate 101 is made of ceramics, the metallized wiring layer is formed on the upper surface by baking a metal paste made of tungsten (W), molybdenum (Mo) -manganese (Mn), or the like at a high temperature. Further, when the base 101 is made of resin, when the base 101 is molded, one end of a lead terminal made of copper (Cu), iron (Fe) -nickel (Ni) alloy, or the like protrudes into the base 101. To be fixed.

  The frame body 102 is made of a metal such as aluminum (Al) or Fe-Ni-cobalt (Co) alloy, a ceramic such as an alumina-based sintered body, or a resin such as an epoxy resin. It is formed by a molding technique such as molding. Furthermore, a through hole is formed in the central portion of the frame body 102 so as to spread outward as it goes upward. To improve the light reflectance of the inner peripheral surface of the through hole, Al or the like is provided on the inner peripheral surface. The metal is deposited by vapor deposition or plating. The frame 102 is bonded to the upper surface of the base 101 with a brazing material such as solder, silver brazing, or a resin adhesive.

  Then, a wiring conductor (not shown) formed on the surface of the substrate 101 and the electrode of the light emitting element 105 are electrically connected via a bonding wire (not shown), and then the phosphor is applied to the surface of the light emitting element 105. After the layer 104 is formed, the inside of the frame 102 is filled with a transparent resin 106 and thermally cured, whereby the light emitted from the light emitting element 105 is converted by the phosphor layer 104 to extract light having a desired wavelength spectrum. Can be made with equipment. Then, a light-transmitting lid 103 is joined to the upper surface of the frame 102 with solder, a resin adhesive, or the like to form a light emitting device. In addition, the light emitting element 105 is selected to include an ultraviolet region having an emission wavelength of 300 to 400 nm, and the color tone is adjusted by adjusting the mixing ratio of phosphor particles of the three primary colors red, blue, and green contained in the phosphor layer 104. Can be designed freely.

Various materials are used for such phosphor particles. For example, red is La ₂ O ₂ S: Eu (Eu-doped La ₂ O ₂ S) phosphor particles, and green is ZnS: Cu, Al fluorescence. The body particles, blue, are phosphor particles of (BaMgAl) ₁₀ O ₁₂ : Eu.

In general, the phosphor particles are powder, and it is difficult to form the phosphor layer 104 with the phosphor particles alone. Therefore, the phosphor particles are mixed in a transparent member such as a resin or glass to form the surface of the light emitting element 105. In general, the phosphor layer 104 is applied.
Japanese Patent Laid-Open No. 2003-37298

  However, in the light emitting device, there is a problem that the light emission color variation of the light emitting device is large. Generally, the emission color variation of light emitting devices such as light bulbs and fluorescent lamps needs to be controlled within a range of 10% above and below the color temperature, and in order to popularize light emitting devices using light emitting diodes as light emitting elements, light emitting devices It is important to reduce the emission color variation.

  The variation in the light emission color of the light emitting device tends to depend on the variation in the light emission efficiency of the light emitting device, and by improving the light emission efficiency, stable light emission with little variation in the light emission intensity can be achieved. The variation of can also be suppressed.

  As a means for improving the luminous efficiency, it has been proposed that the phosphor particle content and thickness of the phosphor layer 104 be in an appropriate range. Accordingly, the wavelength of light from the light emitting element 105 can be efficiently converted by the phosphor particles, and the wavelength-converted fluorescence can be efficiently emitted from the phosphor layer 104, so that the light emission efficiency can be improved.

  However, by improving the luminous efficiency by making the phosphor particle content and thickness of the phosphor layer 104 in an appropriate range in this way, it is possible to suppress variations in the emission color of the light emitting device, but in recent lighting devices, etc. For applications, further reduction in emission color variation is required.

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to reduce variations in emission color of a light emitting device.

The light-emitting device of the present invention includes a light-emitting element having an emission wavelength of 300 to 400 nm, La ₂ O ₂ S: Eu phosphor particles arranged on the optical axis of the light-emitting element, and ZnS: Cu, Al fluorescence. Body particles and a phosphor layer formed by mixing phosphor particles of (BaMgAl) ₁₀ O ₁₂ : Eu into a transparent member, and the average particle diameter of each phosphor particle is 1 to 50 μm It is characterized by.

  In the light emitting device of the present invention, preferably, the transparent member is a resin or glass transparent to light emitted from the light emitting element and fluorescence emitted from the respective phosphor particles excited by light from the light emitting element. It is characterized by comprising.

  In the light emitting device of the present invention, preferably, the transparent member has a higher transmittance for the fluorescence emitted by the phosphor particles than the transmittance for the light emitted by the light emitting element.

  The illuminating device of the present invention is characterized in that the light emitting device of the present invention is installed in a predetermined arrangement.

The light emitting device of the present invention includes a light emitting element having an emission wavelength of 300 to 400 nm, a phosphor particle of La ₂ O ₂ S: Eu, and a phosphor of ZnS: Cu, Al disposed on the optical axis of the light emitting element. A phosphor layer formed by mixing particles and (BaMgAl) ₁₀ O ₁₂ : Eu phosphor particles in a transparent member, and the average particle diameter of each phosphor particle is 1 to 50 μm, The surface area of the phosphor particles can be increased, the amount of light irradiated per phosphor particle can be increased, and the emission surface of the fluorescence can be increased to increase the amount of radiation. As a result, the light emission efficiency can be improved, and thereby the variation in emission color can be further reduced.

  In addition, such a particle size can reduce the probability of existence of defects and impurities in the crystal of the phosphor particles, and effectively prevents the fluorescence wavelength from being varied due to defects and impurities in the crystal. Thus, the variation in the emission color can be extremely effectively suppressed.

  In the light emitting device of the present invention, the transparent member is made of a resin or glass that is transparent to the light emitted from the light emitting element and the respective fluorescence emitted from the respective phosphor particles excited by the light from the light emitting element. The light emitted from the light-emitting element can be satisfactorily irradiated onto the phosphor particles, and the luminous efficiency can be improved and the emission color variation can be effectively suppressed. In addition, when the transparent member absorbs the fluorescence emitted by the phosphor particles, the proportion of the fluorescence absorbed by the transparent member varies depending on the distance from the phosphor particles to the outer surface of the phosphor layer, resulting in emission color variations. Although it becomes easy, by making it transparent with respect to each fluorescence emitted from the phosphor particles, the fluorescence is not absorbed by the transparent member, and the emission color variation can be extremely reduced.

  In the light-emitting device of the present invention, since the transparent member has a higher transmittance for the fluorescence emitted by the phosphor particles than the transmittance for the light emitted by the light-emitting element, the light emitted from the light-emitting element has a wavelength due to the phosphor particles. It is possible to effectively suppress the direct emission from the phosphor layer without being converted and to efficiently emit the fluorescence from the phosphor particles from the phosphor layer, thereby further suppressing the emission color variation.

  Since the light emitting device of the present invention is installed in a predetermined arrangement, the lighting device of the present invention uses light emission by recombination of electrons of a light emitting element made of a semiconductor. Thus, a small illuminating device that can have lower power consumption and longer life than the existing illuminating device can be obtained. As a result, fluctuations in the center wavelength of light generated from the light emitting element can be suppressed, light can be emitted with a stable radiant light intensity and radiant light angle (light distribution distribution) over a long period of time, and an irradiation surface It is possible to provide a lighting device in which uneven color and uneven illuminance distribution are suppressed.

  In addition, the light emitting device of the present invention is installed in a predetermined arrangement as a light source, and by installing a reflection jig, an optical lens, a light diffusing plate, etc. optically designed in an arbitrary shape around these light emitting devices, It can be set as the illuminating device which radiates | emits the light of this light distribution.

  The light emitting device of the present invention will be described in detail below. FIG. 1 is a cross-sectional view showing an example of an embodiment of a light emitting device according to the present invention. 1 is a base, 2 is a frame, 3 is a lid, 4 is a phosphor layer, 5 is a light emitting element, and 6 is a resin. Or a transparent member such as glass, and the light emitting device is mainly composed of these members.

The light-emitting device of the present invention includes a light-emitting element 5 having an emission wavelength of 300 to 400 nm, La ₂ O ₂ S: Eu phosphor particles arranged on the optical axis of the light-emitting element 5, ZnS: Cu, Al And phosphor layer 4 in which phosphor particles of (BaMgAl) ₁₀ O ₁₂ : Eu are mixed in a transparent member, and the average particle diameter of each phosphor particle is 1 to 50 μm .

  As a result, the surface area of the phosphor particles can be increased, the amount of light irradiated per phosphor particle can be increased, and the emission surface of the fluorescence can be increased to increase the amount of radiation. As a result, the light emission efficiency can be improved, and thereby the variation in emission color can be further reduced.

  In addition, such a particle size can reduce the probability of existence of defects and impurities in the crystal of the phosphor particles, and effectively prevents the fluorescence wavelength from being varied due to defects and impurities in the crystal. Thus, the variation in the emission color can be extremely effectively suppressed.

  The substrate 1 in the present invention is an insulator made of an aluminum oxide sintered body (alumina ceramic), an aluminum nitride sintered body, a mullite sintered body, a ceramic such as glass ceramic, or a resin such as an epoxy resin, It is a support member that supports the light emitting element 5 having an emission wavelength of 300 to 400 nm.

  A metallized wiring layer made of metal powder such as W, Mo, or Mn is formed on the surface or inside of the substrate 1 to electrically connect the inside and outside of the light emitting device. A lead terminal made of a metal such as Cu or Fe—Ni alloy is joined to the metallized wiring layer on the surface exposed to the outside. The base 1 has a light emitting element 5 having an emission wavelength of 300 to 400 nm such as an LED, such as silver (Ag) -epoxy resin (Ag paste) in which a metal powder such as solder, a resin adhesive, or silver is mixed in the resin. It is joined with the joining material. Then, the electrode of the light emitting element 5 is electrically connected to the metallized wiring layer of the substrate 1 through a bonding wire (not shown).

  It should be noted that a metal having excellent corrosion resistance, such as Ni or gold (Au), should be deposited on the exposed surface of the metallized wiring layer in a thickness of about 1 to 20 μm. In addition to preventing this, the connection between the metallized wiring layer and the light emitting element 5 and the connection between the metallized wiring layer and the bonding wire can be strengthened. Therefore, an Ni plating layer having a thickness of about 1 to 10 μm and an Au plating layer having a thickness of about 0.1 to 3 μm are sequentially deposited on the exposed surface of the metallized wiring layer by an electrolytic plating method or an electroless plating method. Is more preferable.

  Further, the upper surface of the substrate 1 is not electrically short-circuited to the metallized wiring layer in order to effectively suppress the transmission of light to the lower surface side of the substrate 1 and efficiently reflect the light to the upper side of the substrate 1. Thus, it is preferable to form a metal such as Al, Ag, Au, platinum (Pt), or Cu as the reflective layer by vapor deposition or plating.

Next, phosphor particles are mixed into the surface of the light emitting element 5 in order to convert light of the light emitting element 5 having an emission wavelength of 300 to 400 nm into light having a desired wavelength (for example, visible light of 420 to 780 nm). The phosphor layer 4 made of a transparent member is applied and formed. The phosphor particles are La ₂ O ₂ S: Eu that emits red (about 580 to 780 nm) fluorescence, ZnS: Cu, Al, blue (420 to 550 nm) that emits green (about 450 to 650 nm) fluorescence. (BaMgAl) ₁₀ O ₁₂ : Eu.

  Since these phosphor particles are powder and it is difficult to form only the phosphor particles on the surface of the light emitting element 5, the phosphor particles are mixed in the transparent member and applied to the surface of the light emitting element 5. Layer 4 is assumed. The transparent member is made of epoxy resin, silicone resin, acrylic resin, glass or the like.

  The light emitting element 5 having an emission wavelength of 300 to 400 nm generates light in a wavelength band mainly including the ultraviolet region, and the phosphor particles efficiently convert light in this wavelength band into fluorescence. Can do.

In the present invention, La ₂ O ₂ S: Eu phosphor particles, ZnS: Cu, Al phosphor particles, and (BaMgAl) ₁₀ O ₁₂ : Eu phosphor particles have a particle diameter of 1 to 50 μm. However, when the particle diameter is less than 1 μm, the existence probability of defects and impurities contained in the crystal of the phosphor particles tends to increase with respect to the surface of the phosphor particles contributing to light emission, and the energy of ultraviolet light is consumed by the defects and impurities. Is likely to be. As a result, the efficiency with which the energy of ultraviolet light is converted to a desired wavelength is lowered, and the intensity of the fluorescence generated by the phosphor particles tends to decrease. That is, if there are phosphor particles having a particle size that is too small, phosphor particles that emit strong fluorescence and phosphor particles that emit fluorescence weakly exist at the same time, which causes variations in emission color.

  On the other hand, when the particle diameter of the phosphor particles exceeds 50 μm, the phosphor particle surface that contributes to light emission with respect to the volume of the phosphor particles becomes narrow, and as a result, the emission intensity tends to decrease. That is, if there is a phosphor particle having an excessively large particle diameter, phosphor particles that emit strong fluorescence and phosphor particles that emit weak fluorescence exist at the same time, which causes variations in emission color.

  In the light emitting device of the present invention, the transparent member of the phosphor layer 4 is transparent to the light emitted from the light emitting element 5 and the respective fluorescence emitted from the respective phosphor particles excited by the light from the light emitting element 5. It is preferably made of a new resin or glass.

  Thereby, the light emitted from the light emitting element 5 can be satisfactorily applied to the phosphor particles, the luminous efficiency can be improved, and the emission color variation can be effectively suppressed. In addition, when the transparent member absorbs the fluorescence emitted by the phosphor particles, the proportion of the fluorescence absorbed by the transparent member varies depending on the distance from the phosphor particles to the outer surface of the phosphor layer, resulting in emission color variations. Although it becomes easy, by making it transparent with respect to each fluorescence emitted from the phosphor particles, the fluorescence is not absorbed by the transparent member, and the emission color variation can be extremely reduced.

When an opaque binder is used for La ₂ O ₂ S: Eu that emits red (about 580 to 780 nm) fluorescence, the red component of the light emitted from the light emitting device is attenuated, and as a result, color variation tends to occur. .

When a binder that is opaque to blue (420 to 550 nm) (BaMgAl) ₁₀ O ₁₂ : Eu is used, the blue component of the light emitted from the light emitting device is attenuated, resulting in color variations. .

  When an opaque binder is used for ZnS: Cu, Al that emits green (about 450 to 650 nm) fluorescence, the green component of the light emitted from the light emitting device is attenuated, and as a result, color variations are likely to occur.

  Therefore, when each fluorescence varies, the emission color of the light emitting device radiated as the mixed light of the fluorescence of each wavelength will vary.

  Examples of the transparent member transparent to the light of the light emitting element 5 and the fluorescence of the phosphor particles include sol-gel glass obtained by hydrolysis of epoxy resin, silicone resin, acrylic resin, or metal alkoxide. .

  Furthermore, in the light emitting device of the present invention, it is preferable that the transparent member of the phosphor layer 4 has a higher transmittance for the fluorescence emitted by the phosphor particles than the transmittance for the light emitted by the light emitting element 5. Thereby, it is possible to effectively suppress light emitted from the light emitting element 5 from being directly emitted from the phosphor layer 4 without being wavelength-converted by the phosphor particles, and to efficiently emit fluorescence from the phosphor particles from the phosphor layer 4. By radiating well, the emission color variation can be further suppressed.

  As such a transparent member having a higher transmittance for the fluorescence of the phosphor particles than the transmittance for the light of the light emitting element 5, an epoxy resin may be mentioned.

  The phosphor layer 4 preferably has a thickness of 0.1 to 0.3 mm. Thereby, the light emission efficiency is improved, and the emission color variation is reduced accordingly.

  The phosphor layer 4 may have a transparent member content of 80 to 150 parts by weight when the total content of the phosphor particles is 100 parts by weight. Thereby, the light emission efficiency is improved, and the emission color variation is reduced accordingly.

  The light-emitting device of the present invention has the light-emitting element 5 mounted on the mounting portion of the light-emitting element 5 of the base 1 and electrically connects the light-emitting element 5 to an external external electric circuit via a bonding wire and a metallized wiring layer. The frame body 2 is joined to the periphery of the mounting portion of the light emitting element 5 on the upper surface by a resin adhesive, solder, or the like, and a transparent member 6 such as glass or transparent resin is filled inside the frame body 2. The translucent cover 3 is joined to the upper surface of 2 by a resin adhesive, solder or the like.

  The frame 2 is made of an aluminum oxide sintered body (alumina ceramic), an aluminum nitride sintered body, a mullite sintered body, a ceramic such as glass ceramics, or an insulator made of a resin such as an epoxy resin, Al, It consists of metals, such as Cu, Ag, a Fe-Ni-Co alloy, a Fe-Ni alloy, stainless steel, brass.

  The lid 3 is made of a transparent member such as glass, sapphire, quartz, or a resin (plastic) such as epoxy resin, silicone resin, acrylic resin, and the like. The bonding wire and the transparent member 6 are protected, and the inside of the light emitting element storage package is hermetically sealed. Further, by forming the lid 3 in a lens shape and adding the function of an optical lens, it is possible to collect or disperse the fluorescence and extract the fluorescence to the outside with a desired radiation angle and intensity distribution.

  In addition, the light emitting device of the present invention is a circular shape in which one device is installed in a predetermined arrangement, or a plurality of light emitting devices, for example, a lattice shape, a staggered shape, a radial shape, or a plurality of light emitting devices. In addition, a lighting device can be obtained by installing the light emitting device groups in a plurality of concentric shapes so as to have a predetermined arrangement. Thereby, since light emission by recombination of electrons of the light emitting element 5 made of a semiconductor is used, it is possible to achieve lower power consumption and longer life than a lighting device using a conventional discharge, and generate less heat. It can be set as a small illuminating device. As a result, fluctuations in the center wavelength of the light generated from the light emitting element 5 can be suppressed, and light can be irradiated with a stable radiant light intensity and radiant light angle (light distribution) over a long period of time. It can be set as the illuminating device by which the color nonuniformity in the surface and the bias of illuminance distribution were suppressed.

  Also, by installing a plurality of light emitting devices of the present invention in a predetermined arrangement as a light source, and installing a reflecting jig, an optical lens, a light diffusing plate, etc. that are optically designed in an arbitrary shape around these light emitting devices It can be set as the illuminating device which can radiate | emit light of arbitrary light distribution.

  For example, a plurality of light emitting devices 7 are arranged in a plurality of rows on the light emitting device drive circuit board 9 as shown in the plan view and the cross-sectional view shown in FIGS. 3 and 4, and are optically designed in an arbitrary shape around the light emitting device 7. In the case of an illuminating device in which the reflecting jig 8 is installed, in a plurality of light emitting devices 7 arranged on the adjacent row, an arrangement in which the interval between the adjacent light emitting devices 7 is not shortest, a so-called staggered pattern. It is preferable that That is, when the light emitting devices 7 are arranged in a grid, the light emitting devices 7 serving as light sources are arranged in a straight line so that the glare becomes strong, and such a lighting device enters the human vision. Thus, discomfort and eye damage are likely to occur, but by forming a staggered pattern, glare is suppressed and discomfort and damage to the eyes of the human eye can be reduced. Further, since the distance between the adjacent light emitting devices 7 is increased, thermal interference between the adjacent light emitting devices 7 is effectively suppressed, and the heat in the light emitting device driving circuit board 9 on which the light emitting device 7 is mounted is reduced. Clouding is suppressed, and heat is efficiently dissipated outside the light emitting device 7. As a result, it is possible to manufacture a long-life lighting device with stable optical characteristics over a long period of time with little obstacles to human eyes.

  In addition, the lighting device is a concentric arrangement of a circular or polygonal light emitting device 7 group composed of a plurality of light emitting devices 7 on the light emitting device drive circuit board 9 as shown in the plan view and the sectional view shown in FIGS. In the case of the illuminating device formed in a plurality of groups, it is preferable to increase the number of the light emitting devices 7 arranged in one circular or polygonal light emitting device group 7 toward the outer peripheral side from the center side of the illuminating device. Thereby, more light-emitting devices 7 can be arrange | positioned, maintaining the space | interval of light-emitting devices 7 moderately, and the illumination intensity of an illuminating device can be improved more. Moreover, the density of the light-emitting device 7 in the central portion of the lighting device can be reduced to suppress heat accumulation in the central portion of the light-emitting device driving circuit board 9. Therefore, the temperature distribution in the light emitting device drive circuit board 9 becomes uniform, heat is efficiently transmitted to the external electric circuit board on which the lighting device is installed and the heat sink, and the temperature rise of the light emitting device 7 can be suppressed. As a result, the light-emitting device 7 can operate stably over a long period of time, and a long-life lighting device can be manufactured.

  Examples of such lighting devices include general lighting fixtures, chandelier lighting fixtures, residential lighting fixtures, office lighting fixtures, store lighting, display lighting fixtures, street lighting fixtures, used indoors and outdoors. Guide light fixtures and signaling devices, stage and studio lighting fixtures, advertising lights, lighting poles, underwater lighting lights, strobe lights, spotlights, security lights embedded in power poles, emergency lighting fixtures, flashlights, Examples include electronic bulletin boards and the like, backlights for dimmers, automatic flashers, displays and the like, moving image devices, ornaments, illuminated switches, optical sensors, medical lights, in-vehicle lights, and the like.

  Examples of the light emitting device of the present invention will be described below.

  Using the gallium nitride semiconductor light-emitting element having a main emission peak of 382 nm as the light-emitting element 5, the light-emitting device of the present invention was manufactured as follows.

As the phosphor particles contained in the phosphor layer 4, a base body 1 made of alumina ceramic, a frame body 2 made of aluminum, a lid body 3 made of epoxy resin, and a transparent member 6 made of silicone resin are used. , La ₂ O ₂ S: Eu particles, ZnS: Cu, Al particles and (BaMgAl) ₁₀ O ₁₂ : Eu particles were used. The blending ratio of each phosphor particle was adjusted so that the light emission color of the light emitting device was 6000K in relative color temperature.

Silicone resin was used as the transparent member 6 for mixing the phosphor particles. The silicone resin is transparent to both the fluorescence emitted from the phosphor particles and the light emitted from the light emitting element 5, and as shown in Table 1, the silicone resin is more transparent than the transmittance of the light emitted from the light emitting element 5 to the transparent member 6. The transmittance of the fluorescence emitted from the phosphor particles with respect to 6 was higher.

  Phosphor particles and silicone resin were added by adding ethanol to the phosphor particles and stirring with a mixer for 24 hours, followed by drying and removing ethanol at 100 ° C. in an air atmosphere. Three particle size distributions (see Table 1) The phosphor layer 4 having a thickness of 0.2 mm was formed so as to cover the light emitting element 3 with a transparent resin containing the phosphor particles of), and a sample of the light emitting device having the configuration of FIG.

And the emission color dispersion | variation with respect to each 10 pieces of these samples was evaluated. The emission color variation was evaluated by evaluating the relative color temperature variation. The relative color temperature is the temperature of the complete black body when the color of the object to be evaluated matches the color when the temperature of the complete black body is raised, and the relative color temperature is measured using an integrating sphere method. The measurement was performed using a total luminous flux measurement system (SLMS1021 manufactured by Labsphere). The results are shown in Table 2.

  From Table 1, the sample No. 1 in which the phosphor particle diameter distribution in the phosphor layer 4 is a particle having a particle size of 0.1 μm to 50 μm. No. 1 is a sample No. 1 in which the phosphor particle diameter distribution in the phosphor layer 4 is a particle having a particle size of 1 μm to 50 μm. Compared with 2, the relative color temperature variation increased.

  When the phosphor particle diameter is less than 1 μm, the existence probability of defects and impurities contained in the crystal of the phosphor particles is likely to increase with respect to the surface of the phosphor particles contributing to light emission, and the energy of the light emitting element 5 is due to defects and impurities. The possibility of being consumed increases. As a result, the efficiency with which the energy of the light emitting element 5 is converted to a desired wavelength is reduced, and the intensity of the fluorescence generated by the phosphor particles is likely to be reduced.

  That is, sample no. Since the phosphor layer 4 of 1 includes phosphor particles having a phosphor particle diameter of less than 1 μm, the result of the variation in the emission intensity for each phosphor particle included in the phosphor layer 4 is greater than the above consideration. Sample No. The relative color temperature variation of No. 1 seems to have increased.

  In addition, the sample particle number distribution in which the phosphor particle diameter distribution in the phosphor layer 4 is 1 μm or more and 500 μm or less is shown. 3 is a sample No. 3 in which the phosphor particle diameter distribution in the phosphor layer 4 is a particle having a particle size of 1 μm or more and 50 μm or less. Compared with 2, the relative color temperature variation increased rapidly.

  When the particle diameter of the phosphor particles exceeds 50 μm, the phosphor particle surface contributing to light emission becomes narrower with respect to the volume of the phosphor particles. That is, the phosphor particle surface contributing to light emission with respect to the volume of the phosphor layer 4 becomes narrow, and the light emission intensity is likely to decrease.

  That is, sample no. 3 includes phosphor particles having a phosphor particle diameter of more than 50 μm, and as a result of the above consideration, the emission intensity variation of each phosphor particle included in the phosphor layer 4 is increased. Sample No. The relative color temperature variation of No. 3 seems to have increased.

  From the above results, the sample No. 1 in which the phosphor particle size distribution in the phosphor layer 4 is a particle having a particle size of 1 μm to 50 μm. 2 gave the smallest relative color temperature variation. This is because, in each phosphor particle in the phosphor layer 4, light emitted from the light emitting element 5 is less consumed by defects in the phosphor particle, and the phosphor particles in the phosphor layer 4 are efficiently excited. It is considered that as a result of obtaining an appropriate amount of the phosphor particle surface area with respect to the volume of the phosphor layer 4, the variation in relative color temperature is reduced.

  From the above results, it was possible to obtain a light emitting device with little emission color variation by forming a light emitting device in which the particle size distribution in the phosphor layer 4 is particles of 1 μm to 50 μm.

  It should be noted that the present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the scope of the present invention.

  In addition, the lighting device of the present invention is not limited to one in which a plurality of light emitting devices 7 are installed in a predetermined arrangement, but may be one in which one light emitting device 7 is installed in a predetermined arrangement.

It is sectional drawing which shows an example of embodiment of the light-emitting device of this invention. It is sectional drawing which shows the conventional light-emitting device. It is a top view which shows an example of embodiment of the illuminating device of this invention. It is sectional drawing of the illuminating device of FIG. It is a top view which shows the other example of embodiment of the illuminating device of this invention. It is sectional drawing of the illuminating device of FIG.

Explanation of symbols

1: Base body 2: Frame body 3: Cover body 4: Phosphor layer 5: Light emitting element 6: Transparent member 7: Light emitting device 8: Reflecting jig 9: Light emitting device driving circuit board

Claims (4)

A light emitting device having an emission wavelength of 300 to 400 nm, La ₂ O ₂ S: Eu phosphor particles, ZnS: Cu, Al phosphor particles and (BaMgAl) ₁₀ disposed on the optical axis of the light emitting device And a phosphor layer obtained by mixing phosphor particles of O ₁₂ : Eu in a transparent member, wherein each phosphor particle has an average particle diameter of 1 to 50 μm. 2. The transparent member is made of a resin or glass that is transparent to light emitted from the light emitting element and fluorescence emitted from each of the phosphor particles excited by the light from the light emitting element. The light-emitting device of description. The light emitting device according to claim 2, wherein the transparent member has a higher transmittance with respect to the fluorescence emitted by the phosphor particles than a transmittance with respect to the light emitted by the light emitting element. An illuminating device, wherein the light emitting device according to any one of claims 1 to 3 is installed in a predetermined arrangement.

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