JP2008235680A - Light emitting device - Google Patents

Abstract

【Task】
Provided is a light emitting device capable of easily obtaining light emission of a desired chromaticity while suppressing a decrease in color rendering.
[Solution]
A blue light emitting element that emits blue light and a phosphor layer that is coated on the blue light emitting element and includes a phosphor that is excited by the blue light and emits monochromatic light other than blue light. A light-emitting device having a spectral spectrum in which the emission intensity at the peak wavelength is 35% or less of the emission intensity at the peak wavelength of the phosphor, or a near-ultraviolet light-emitting element that emits near-ultraviolet light and the ultraviolet-light-emitting element coated thereon It has a phosphor layer containing a phosphor that emits monochromatic light when excited by near ultraviolet light, and the emission intensity at the peak wavelength of the near ultraviolet light is 35% or less of the emission intensity at the peak wavelength of the phosphor. It is a light emitting device having a certain spectrum.
[Selection figure] None

Description

  The present invention relates to a light emitting device using a light emitting element such as a light emitting diode.

  LED lamps using light emitting diodes (LEDs) are rapidly expanding in various fields such as backlights for liquid crystal displays, mobile phones, information terminals, and indoor / outdoor advertisements. In addition, LED lamps have features such as long life and high reliability, and low power consumption, impact resistance, high purity display color, lightness, thinness, and other features. Application of is also being attempted. When such an LED lamp is applied to general illumination applications, it is important to obtain white light emission.

Typical methods for realizing white light emission with an LED lamp are (1) a method using three LED chips that emit light in blue, green and red colors, and (2) a blue light emitting LED chip and yellow or orange light emission. There are three methods: (3) a method of combining an ultraviolet light emitting LED chip and a blue, green and red light emitting three-color mixed phosphor. Of these, the method (2) is generally widely used. And as a structure of the LED lamp to which the above-mentioned method (2) is applied, a transparent resin mixed with a phosphor is poured into a cup-shaped frame equipped with an LED chip, and this is cured to contain the phosphor. A structure in which a resin layer is formed is common (see, for example, Patent Document 1). In addition to the above-mentioned bullet-type LED elements and SMD (Surface Mounting Device) type, a chip-on-board (COB) in which a plurality of LED chips are mounted on a substrate (board) has been developed for the purpose of increasing the brightness. Attention has been paid. Characteristics required for general illumination include color rendering properties as an indicator of color appearance, in particular average color rendering index Ra, in addition to high luminous efficiency as an LED lamp. For this color rendering property, lineups such as Ra 80 to 85 and Ra 90 or higher which are similar to fluorescent lamps are required.

  Color rendering is an evaluation of the color appearance of a light source using illumination close to natural light as the reference light, and the color shift when the test color specified in JIS is illuminated with the sample light source and the reference light, respectively. The numerical value of the size is the color rendering index. The color rendering index includes an average color rendering index Ra and a special color rendering index Ri. It is expressed as an average value of 1 to 8 color rendering evaluation values. The special color rendering index Ri is the test No. Expressed as individual special color rendering evaluation values of 9 to 15. The color rendering index Ra is an index indicating whether the color of the white light source that is the reference light source is faithfully reproduced. As a rule, the color rendering index Ra is better as it is closer to 100.

  In general, a so-called high color rendering type white LED lamp having a high average color rendering index Ra has a yellow emission from a yellow phosphor such as YAG that emits light having a wavelength of 540 nm to 560 nm by blue emission from an LED chip, and a wavelength. White light with excellent color rendering properties is synthesized by red light emitted from a red light emitter emitting light of 620 nm.

  In order to increase the average color rendering index Ra, it is usual to use a red phosphor that emits red light as described above. The red phosphor not only uses blue light near 460 nm for excitation, but also a green phosphor. Since the green light emitted from the yellow light and the yellow light emitted from the yellow phosphor are also used for excitation, the luminous efficiency of the LED lamp is significantly reduced when the red light emitting phosphor is used.

  Therefore, as a countermeasure, an attempt has been made to use a red light emitting LED chip instead of a red light emitting phosphor. However, since the red light emission from the LED chip is not a broad light emission with a narrow half-value width, the color temperature can be lowered, but the increase range of the average color rendering index Ra is small. Therefore, it is difficult to realize high color rendering properties such as an average color rendering index Ra85 or 90 or more.

  In addition, regarding the light color, that is, the color temperature, when considering HID lamps, light bulbs, and fluorescent lamps, a lineup up to color temperatures of 6700K, 5000K, 4200K, and 3000K (2850K) is required. In general, in order to cope with such a lineup, a white LED lamp corresponding only to each color temperature is required.

On the other hand, a variable color LED lamp has been proposed (see, for example, Patent Document 2). However, since these variable color LEDs are only variable colors in one direction by adjustment from the white LED, the color deviation (duv) shifts and deviates from black body radiation, and the change in color temperature However, there is a problem that the quality of the color deteriorates due to the change in deviation. Therefore, there is a need for a technique that realizes not only a variable color in one direction but also a variable color in an arbitrary direction. Furthermore, there is a problem that the average color rendering index Ra decreases as the color temperature is lowered.
JP 2001-148516 A JP 2005-1000079 A

  The present invention has been made to solve such problems, and an object of the present invention is to provide a light-emitting device that can easily obtain light emission of desired chromaticity while suppressing deterioration in color rendering. Yes.

  The light-emitting device according to claim 1 includes a phosphor layer including a blue light-emitting element that emits blue light and a phosphor that is coated on the blue light-emitting element and is excited by the blue light to emit monochromatic light other than blue light. And having a spectral spectrum in which the emission intensity at the peak wavelength of the blue light is 35% or less of the emission intensity at the peak wavelength of the phosphor.

  The light-emitting device according to claim 2 includes a blue light-emitting element that emits blue light and a first light-emitting unit that includes a transparent resin layer coated on the blue light-emitting element; a blue light-emitting element that emits blue light; A phosphor that is coated on a light-emitting element and emits monochromatic light other than blue light when excited by the blue light, wherein the emission intensity at the peak wavelength of the blue light is 35% or less of the emission intensity at the peak wavelength of the phosphor; A second light-emitting portion having a spectral spectrum as described above.

  The light emitting device according to claim 3 is the light emitting device according to claim 2, wherein the second light emitting unit is a green light emitting unit including a green light emitting phosphor that is excited by the blue light and emits green light, and the blue light emitting unit. A yellow light emitting part including a yellow light emitting phosphor that emits yellow light when excited by light, and a red light emitting part that includes a red light emitting phosphor that emits red light when excited by the blue light. The light emitting device according to claim 2.

  The light emitting device according to claim 4 includes a phosphor layer including a near ultraviolet light emitting element that emits near ultraviolet light and a phosphor that is coated on the ultraviolet light emitting element and is excited by the near ultraviolet light to emit monochromatic light. Thus, it has a spectral spectrum in which the emission intensity at the peak wavelength of the near ultraviolet light is 35% or less of the emission intensity at the peak wavelength of the phosphor.

  The light emitting device according to claim 5 includes a near ultraviolet light emitting element that emits near ultraviolet light and a phosphor that is coated on the near ultraviolet light emitting element and is excited by the near ultraviolet light to emit blue light, A blue light-emitting portion having a spectral spectrum in which the light emission intensity at the peak wavelength of light is 35% or less of the light emission intensity at the peak wavelength of the phosphor; a near-ultraviolet light-emitting element that emits near-ultraviolet light, and the near-ultraviolet light-emitting element And a phosphor that is coated and excited by the near-ultraviolet light to emit green light, and has a spectral spectrum in which the emission intensity at the peak wavelength of the near-ultraviolet light is 35% or less of the emission intensity at the peak wavelength of the phosphor. A green light emitting part; a near ultraviolet light emitting element that emits near ultraviolet light; and a phosphor that is coated on the near ultraviolet light emitting element and is excited by the near ultraviolet light to emit yellow light. A yellow light-emitting part having a spectral spectrum in which the emission intensity at the peak wavelength of the near-ultraviolet light is 35% or less of the emission intensity at the peak wavelength of the phosphor; a near-ultraviolet light-emitting element that emits near-ultraviolet light, and the vicinity thereof A phosphor that is coated on an ultraviolet light emitting element and emits red light when excited by the near ultraviolet light, and the emission intensity at the peak wavelength of the near ultraviolet light is 35% or less of the emission intensity at the peak wavelength of the phosphor; A red light-emitting portion having a certain spectrum.

  A light-emitting device according to a sixth aspect is the light-emitting device according to any one of the second, third, and fifth aspects, wherein the light-emitting portions are arranged in a predetermined arrangement pattern on the substrate.

  A light-emitting device according to a seventh aspect is the light-emitting device according to the sixth aspect, wherein the predetermined arrangement pattern is a line shape or a matrix shape.

  A light emitting device according to an eighth aspect is characterized in that in the light emitting device according to any one of the second, third, fifth, sixth and seventh aspects, white light is emitted by light from the light emitting section.

  The light emitting device according to claim 9 is the light emitting device according to any one of claims 2, 3, 5, 6, 7, and 8, and emits light having a variable color gamut adjusted by light from the light emitting portion. It is characterized by doing.

  In the above-described inventions according to claims 1 to 9, the definitions and technical meanings of terms are as follows unless otherwise specified. The blue light emitting element emits blue light having a dominant wavelength of 420 to 480 nm (for example, 460 nm), and excites a phosphor with the emitted blue light to emit visible light. Examples of the blue light emitting element used in the present invention include, but are not limited to, a blue light emitting type LED chip. A light-emitting element that emits near-ultraviolet light emits ultraviolet light having a dominant wavelength of 380 to 410 nm, and excites a phosphor with the emitted ultraviolet light to emit visible light. Examples of the light emitting element that emits near ultraviolet light used in the present invention include, but are not limited to, a near ultraviolet light emitting type LED chip.

  A phosphor used for a light emitting element that emits (emits) blue light emits visible light other than blue light when excited by the blue light, and emits green light when excited by the blue light. Body, a yellow phosphor that emits yellow light when excited by the blue light, and a red phosphor that emits red light when excited by the blue light can be used. A phosphor used in a light emitting element that emits (emits) near ultraviolet light emits visible light when excited by the near ultraviolet light, and emits blue light when excited by the near ultraviolet light. A green phosphor that emits green light when excited by the near ultraviolet light, a yellow phosphor that emits yellow light when excited by the near ultraviolet light, and a red fluorescence that emits red light when excited by the near ultraviolet light The body can be used. The phosphor layer containing the phosphor is formed as a layer in which the phosphor is mixed and dispersed in a transparent resin such as a silicone resin or an epoxy resin. The phosphor layer can be formed so as to directly cover the outside of the light-emitting element, but a transparent resin layer is formed in advance so as to directly cover the light-emitting element, and a layer containing the above-described phosphor is provided thereon. Is also possible. When a blue light emitting element is used, only a transparent resin layer that does not contain a phosphor is formed instead of the phosphor layer that emits blue light.

  A light emitting part having a blue light emitting element that emits blue light and a phosphor layer containing a phosphor has a spectral spectrum in which the emission intensity at the peak wavelength of the blue light is 35% or less of the emission intensity at the peak wavelength of the phosphor. Have Further, in the light emitting part having a near ultraviolet light emitting element that emits near ultraviolet light and a phosphor layer containing a phosphor, the emission intensity at the peak wavelength of the near ultraviolet light is 35% of the emission intensity at the peak wavelength of the phosphor. It has the following spectral spectrum. In such a light emitting part, leakage of blue light or ultraviolet light that excites the phosphor from the phosphor layer containing the phosphor is reduced. An emission color or an emission color close to it can be obtained. As a result, color mixing with other emission colors (single color) is facilitated, and emission having a desired chromaticity can be easily obtained. It should be noted that such a light emitting part having a spectral spectrum in which the emission intensity at the peak wavelength of blue light or ultraviolet light is 35% or less of the emission intensity at the peak wavelength of the phosphor is the type of the phosphor (for example, the structure of the phosphor). , Composition, particle size, etc.) and the amount of phosphor blended in the phosphor layer can be adjusted as appropriate.

  Any arrangement pattern can be used as the arrangement pattern of the light emitting portions, but a line shape or a matrix shape is preferable from the viewpoint of suppressing variations in phosphors among the light emitting portions, particularly variations caused by the coating amount. In addition, when the arrangement pattern is a line, it is easy to make the phosphor types and mixing ratios identical for each light emitting part, and the manufacturing is easy. When the arrangement pattern is a matrix, each light emitting part The color mixing of monochromatic light obtained from the above becomes easy. Further, in the case of forming a phosphor layer in a line shape, that is, on a plurality of light emitting elements, the coating amount of the phosphor layer formed in a line shape, that is, the thickness (optical path length) is made more uniform. be able to.

  According to the light emitting device of claim 1 and claim 4, since leakage of blue light or near ultraviolet light that excites the phosphor from the phosphor layer containing the phosphor is reduced, there is little color mixing of the excitation light. Emission color, that is, emission color of phosphor or near emission color can be obtained, and this makes it easy to mix with other emission colors (single color) and easily emit light with desired chromaticity Can be obtained.

  According to the light emitting device of claim 2, monochromatic light with less color mixing for each light emitting portion and thus excellent color mixing with other light emitting colors (easy color matching) can be obtained. It is possible to provide a light-emitting device that can obtain high light emission efficiency and can easily emit light of desired chromaticity while maintaining.

  According to the light-emitting device of claim 3 and 5, since the red phosphor is used in one of the light-emitting portions in the phosphor layer coated on the light-emitting element, the red phosphor is green light and Light emission that can reduce the absorption of yellow light as excitation light, can achieve higher luminous efficiency while maintaining higher color rendering properties, and can easily realize light emission of desired chromaticity An apparatus can be provided.

  According to the light emitting device of the sixth aspect, since the light emitting portions are arranged in a predetermined arrangement pattern on the substrate, it is possible to provide a light emitting device with high luminance.

  According to the light emitting device of the seventh aspect, since the predetermined arrangement pattern is a line or a matrix, and variations in phosphors are suppressed, it is possible to obtain light emission with less variations in chromaticity and the like.

  According to the light emitting device of the eighth aspect, it is possible to obtain white light at a desired color temperature with little deviation from black body radiation.

  According to the light emitting device of the ninth aspect, since it is possible to change the chromaticity in a desired direction, it is possible to obtain light having a desired chromaticity in which the variable color gamut is adjusted. Therefore, a lineup of variable colors in a range according to the application is possible.

  Therefore, according to the present invention, it is possible to provide a light emitting device that can obtain high light emission efficiency while maintaining high color rendering properties and can easily realize light emission of desired chromaticity. . Also, white light at a desired color temperature with little deviation from black body radiation can be obtained. Furthermore, since it is possible to change the chromaticity in a desired direction, it is possible to obtain light of a desired chromaticity with an adjusted variable gamut, and a lineup of variable colors in a range according to the application. It becomes possible. Further, it can be used not only for illumination purposes but also as a display board.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. 1 and 2 show an example of a light emitting device according to an embodiment of the present invention. FIG. 1 is a plan view of the light emitting device, and FIG. 2 is a cross-sectional view taken along line II-II.

  A light emitting device (COB module) 1 shown in FIGS. 1 and 2 includes a package substrate, for example, a device substrate 4, and a blue light emitting unit group 2B that emits blue light and is arranged on the device substrate 4 in a predetermined arrangement pattern. The green light emitting unit group 2G that emits green light, the red light emitting unit group 2R that emits red light, the reflective layer 31, the circuit pattern 3, the adhesive layer 32, the light diffusing member 33, and the reflector 34 It has.

  The blue light emitting unit group 2B that emits blue light includes a plurality of blue LED chips 2 and a resin layer (transparent resin layer) 9B that does not include a phosphor. The green light emitting unit group 2G that emits green light includes a plurality of blue LED chips 2 and a green phosphor resin layer 9G containing a phosphor that is excited by the blue light and emits green light. The red light emitting unit group 2R that emits red light includes a plurality of blue LED chips 2 and a red phosphor resin layer 9R containing a phosphor that is excited by the blue light and emits red light. Although not illustrated, a yellow light emitting unit group that emits yellow light may be further provided. The yellow light emitting unit group that emits yellow light includes a plurality of blue LED chips and a yellow phosphor resin layer containing a phosphor that is excited by the blue light and emits yellow light.

  The blue LED chip 2 is mounted on a substrate 4 having a circuit pattern 3 via a reflective layer 31 and an adhesive layer 32. Circuit patterns 3 on the cathode side and the anode side are formed on the substrate 4 via the reflective layer 31, respectively. The circuit pattern 3 is made of an alloy of Cu and Ni, Au, or the like. The blue LED chip 2 is coated and filled with a transparent resin or a phosphor-containing resin in which a phosphor is mixed and dispersed in a transparent resin or a transparent resin, and the blue LED chip 2 has such a transparent resin layer or a fluorescent material. The body-containing resin layer 9 is covered. As the transparent resin, for example, a thermosetting resin such as a silicone resin or an epoxy resin is used.

Examples of the green phosphor that emits green light when excited by blue light include RE ₃ (Al, Ga) ₅ O ₁₂ : Ce phosphor (RE represents at least one selected from Y, Gd, and La). YAG phosphors, AE ₂ SiO ₄ : Eu phosphors (AE represents an alkaline earth element such as Sr, Ba, and Ca) and Ca ₃ Sc ₂ Si ₃ O ₁₂ : Ce phosphors such as Ce phosphors phosphor, sialon-based phosphor _{(e.g., Ca X Si y Al Z ON} : Eu 2+), and _Ca 3 _Sc 2 _O 4: is selected from among such Ce phosphor. Examples of red phosphors that emit red light when excited by blue light include oxysulfide phosphors such as La ₂ O ₂ S: Eu phosphors and nitride phosphors (for example, AE ₂ Si ₅ N ₈ : Eu ²⁺ and CaAlSiN ₃ : Eu ²⁺ ) are used, but are not particularly limited. Examples of yellow phosphors that emit yellow light when excited by blue light include RE ₃ (Al, Ga) ₅ O ₁₂ : Ce phosphors (RE represents at least one selected from Y, Gd, and La). YAG phosphors, TAG phosphors such as (Tb, Al) ₅ O ₁₂ : Ce phosphor, sialon-based phosphors (eg, Ca _X Si _Y Al _Z ON: Eu ²⁺ ), AE ₂ SiO ₄ : Eu phosphors (AE represents an alkaline earth element such as Sr, Ba, or Ca) or a silicate phosphor such as Sr ₃ Si ₃ O ₅ : Eu ²⁺ phosphor. For example, a green phosphor having an emission intensity peak (hereinafter referred to as “emission peak”) excited in the blue light and having a wavelength in the range of 500 nm to less than 540 nm, and having an emission peak in the wavelength of 540 nm to less than 590 nm. A yellow phosphor and a red phosphor having an emission peak in a wavelength range of 590 nm to less than 650 nm can be used. The types and blending ratios of the phosphors in the respective light emitting unit groups that emit these monochromatic lights are such that, in each light emitting unit group, the emission intensity at the peak wavelength of blue light is 35% or less of the emission intensity at the peak wavelength of the phosphor. In order to obtain a spectral spectrum, the average color rendering index Ra of light emission from the light emitting device is high, and high light emission efficiency is obtained, and further, white at a desired color temperature is obtained. The

  The device substrate 4 is made of a flat plate made of metal or an insulating material such as a synthetic resin, and has a predetermined shape, for example, a rectangular shape, in order to obtain a light emitting area required for the light emitting device 1. When the device substrate 4 is made of a synthetic resin, it can be formed of, for example, an epoxy resin containing glass powder. When the device substrate 4 is made of metal, the heat dissipation from the back surface of the device substrate 4 is improved, the temperature of each part of the device substrate 4 can be made uniform, and the semiconductor light emitting element that emits light in the same wavelength region. Variation in emission color of the blue LED chip 2 can be suppressed. In addition, as a metal material which has such an effect, the material excellent in the heat conductivity of 10 W / m * K or more, specifically, aluminum or its alloy can be illustrated.

  The reflective layer 31 has a size that allows a predetermined number of blue LED chips 2 to be disposed, and is, for example, attached to the entire surface of the device substrate 4. The reflective layer 31 can be made of a white insulating material having a reflectance of 85% or more in the wavelength region of 400 to 740 nm. As such a white insulating material, a prepreg made of an adhesive sheet can be used. Such a prepreg can be formed, for example, by impregnating a sheet base material with a thermosetting resin mixed with a white powder such as aluminum oxide. The reflective layer 31 is bonded to the entire surface of the device substrate 4 by its own adhesiveness.

  The circuit pattern 3 is bonded to the surface of the reflective layer 31 opposite to the surface to which the device substrate 4 is bonded as an energization element to each blue LED chip 2. The circuit pattern 3 is formed in two rows dotted at predetermined intervals in the longitudinal direction of the device substrate 4 and the reflective layer 31 in order to connect the semiconductor light emitting elements 2 in series, for example. The end-side circuit pattern 3a located on one end side of the row of one circuit pattern 3 is integrally formed with a power feeding pattern portion 3c. Similarly, the end located on one end side of the row of the other circuit pattern 3 The side circuit pattern 3a is integrally formed with a power feeding pattern portion 3d. The power feeding pattern portions 3 c and 3 d are provided side by side at one end in the longitudinal direction of the reflective layer 31, and are separated from each other and insulated by the reflective layer 31. An electric wire (not shown) that reaches the power source is individually connected to each of the power supply pattern portions 3c and 3d by soldering or the like.

  Each blue LED chip 2 is disposed between the circuit patterns 3 adjacent to each other in the longitudinal direction of the device substrate 4, and is bonded to the same surface of the white reflective layer 31 by an adhesive layer 32. Specifically, the other surface parallel to one surface of the element substrate 2 b on which the semiconductor light emitting layer 2 a is laminated is bonded to the reflective layer 31 by the adhesive layer 32. By this adhesion, the circuit pattern 3 and the blue LED chip 2 are arranged in a straight line on the same surface of the reflective layer 31, so that the side surface of the blue LED chip 2 positioned in this arrangement direction and the circuit pattern 3 are close to each other. It is provided so as to face each other. The thickness of the adhesive layer 32 can be, for example, 5 μm or less. For the adhesive layer 32, for example, a translucent adhesive having a thickness of 5 μm or less and a light transmittance of 70% or more, for example, a silicone resin-based adhesive can be suitably used.

  As shown in FIGS. 1 and 2, the electrode of each blue LED chip 2 and the circuit pattern 3 disposed in proximity to both sides of the blue LED chip 2 are connected by bonding wires 6. Further, the end-side circuit patterns 3b positioned on the other end side of the two rows of circuit patterns 3 rows are also connected by bonding wires 6. Therefore, in the case of this embodiment, each blue LED chip 2 is connected in series. The surface light source of the light emitting device 1 is formed by the device substrate 4, the reflective layer 31, the circuit pattern 3, each blue LED chip 2, the adhesive layer 32, and the bonding wire 6.

  The reflector 34 is not individually provided for each one or several blue LED chips 2 but is a single one that surrounds all the blue LED chips 2 on the reflective layer 31, and is formed of, for example, a rectangular frame. The blue LED chip 2 is disposed in a recess 7 formed by the frame. The reflector 34 is bonded to the reflective layer 31, and a plurality of blue LED chips 2 and a circuit pattern 3 are accommodated therein, and the pair of power feeding pattern portions 3c and 3d are positioned outside the reflector 34. ing. The reflector 34 can be formed of, for example, a synthetic resin, and the inner peripheral surface is a reflective surface. The reflecting surface of the reflector 34 can be formed by depositing or plating a metal material having a high reflectivity such as Al or Ni, or can be formed by applying a white paint having a high visible light reflectivity. Alternatively, white powder can be mixed into the molding material of the reflector 34 to make the reflector 34 itself white with high visible light reflectivity. As the white powder, a white filler such as aluminum oxide, titanium oxide, magnesium oxide, barium sulfate can be used. Note that the reflecting surface of the reflector 34 is desirably formed so as to gradually expand in the irradiation direction of the light emitting device 1.

  The transparent resin layer or the phosphor-containing resin layer 9 is a liquid thermosetting resin in which a predetermined phosphor is mixed in a predetermined blending amount for each light emitting unit group (in the case of the transparent resin layer, thermosetting not containing a phosphor). In order to obtain a desired monochromatic light by using an injection device such as a dispenser, the blue LED chips 2 and the bonding wires 6 arranged on the surface and in a straight line of the reflective layer 31 are filled evenly for each line. Thus, it forms by apply | coating and filling in a line form along each semiconductor light emitting element 2 arranged on these straight lines, and hardening a thermosetting resin by heating. In this way, when the transparent resin layer or the phosphor-containing resin layer 9 of each light emitting unit group is formed in a line shape, the manufacturing is easy and the manufacturing cost is low. In addition, when apply | coating the thermosetting resin containing fluorescent substance using injection devices, such as a dispenser, it is preferable to apply | coat with high viscosity of about 14 Pa * s, for example. In addition, when the thermosetting resin is applied, a wall portion 41 can be provided on the substrate 4 in advance for coating each line. As described above, the phosphor-containing resin layer 9 in the same light emitting unit group is formed on the LED blue chip 2 using the thermosetting resin in which the same kind of phosphor is blended at the same blending ratio. Variation in emission of monochromatic light from the body can be suppressed, and emission with less variation in characteristics of light emitted by the phosphor, such as emission intensity and chromaticity (for example, color temperature) can be obtained.

  Next, the arrangement pattern of each light emitting unit group on the substrate will be described.

  FIG. 3 is a plan view schematically showing the light-emitting device 1 described above. As shown in FIG. 3, in the light emitting device 1, three types of light emitting unit groups, a blue light emitting unit group 2B, a green light emitting unit group 2G, and a red light emitting unit group 2R, are arranged in a line. In such a light-emitting device 1, the circuit pattern 3 can also be set so that each light emission part group 2B, 2G, 2R can light-emit separately. In this way, by arranging the three types of light emitting unit groups 2B, 2G, and 2R in a line shape, it is possible to suppress variations in light emission among the respective light emitting unit groups, particularly variations due to the application amount. Moreover, since it is line-shaped, manufacture is also easy.

  The arrangement pattern of each light emission part group is not limited to such an example, for example, as shown in FIG. 4, the blue light emission part group 2B, the green light emission part group 2G, the red light emission part group 2R, and the yellow light emission part It is good also as a structure which arranges four types of light emission part groups of group 2Y in the shape of a line. Also in this example, the circuit pattern 3 can be set so that each of these four types of light emitting unit groups 2B, 2G, 2R, and 2Y can emit light individually. Thus, the light emitting device in which the four types of light emitting unit groups 2B, 2G, 2R, and 2Y are arranged has a variable chromaticity adjustment range compared to the light emitting device shown in FIG. 3 in which the three types of light emitting unit groups are arranged. spread.

  For example, as shown in FIG. 5, the arrangement pattern of each light emitting unit group includes two types of light emitting unit groups of a blue light emitting unit group 2B, a green light emitting unit group 2G, a red light emitting unit group 2R, and a yellow light emitting unit group 2Y. It is good also as a structure arrange | positioned in line shape. In this way, the four types of light emitting unit groups 2B, 2G, 2R, and 2Y are arranged in a two-stage line shape, thereby facilitating color mixing.

  Furthermore, each light emission part group can also take the arrangement pattern arrange | positioned at matrix form. FIG. 6 shows an example thereof, and four types of light emitting unit groups of a blue light emitting unit group 2B, a green light emitting unit group 2G, a red light emitting unit group 2R, and a yellow light emitting unit group 2Y are arranged in a matrix. In such a light emitting device, the circuit pattern 3 can be set so that each of the four types of light emitting unit groups 2B, 2G, 2R, and 2Y can emit light individually. Thus, by arranging the four types of light emitting unit groups 2B, 2G, 2R, and 2Y in a matrix, it becomes easier to mix monochromatic light from each light emitting unit group, and the light diffusing member 33 is omitted, or at least The thickness of the light diffusing member 33 can be reduced, and a decrease in luminance due to the use of the light diffusing member 33 can be suppressed.

  Since the light emitting device 1 according to this embodiment is a COB module, the interval between the LED chips 2 on the substrate 4 can be narrowed (narrow pitch), and a lighter device with higher luminance can be obtained. Moreover, since the space | interval of the blue LED chip 2 can be narrowed, the light by which the monochromatic light obtained from each light emission part group was mixed more can be obtained.

  In the light emitting device 1 of the present embodiment, the applied electric energy is converted into blue light having a main wavelength of 420 to 480 nm (for example, 460 nm) by the blue LED chip 2 and emitted. The emitted blue light is converted into light having a longer wavelength by each phosphor in each light emitting unit group. Each light emitting unit group emits light in which long wavelength light converted by the phosphor and blue light emitted from the blue LED chip 2 are mixed. And when each light emission part group was light-emitted separately, the light which mixed the light emission from the fluorescent substance in each light emission part group, and blue light is light-emitted. In addition, when each light emitting unit group is caused to emit light simultaneously, white light based on a color mixture of light emission from each light emitting unit group is emitted from the light emitting device 1.

  In the present invention, the light emitting part group including the phosphor is configured to have a spectral spectrum in which the emission intensity at the peak wavelength of blue light is 35% or less of the emission intensity at the peak wavelength of the phosphor. From the light emitting unit group including the body, it is possible to obtain a light emission color with little color mixture of blue light, that is, a light emission color of the phosphor or a light emission color close thereto. Therefore, it is possible to easily obtain light emission having a desired single light color or a desired chromaticity.

  In addition, the light emitting device 1 configured as described above can obtain light emission with high luminous efficiency and desired chromaticity while maintaining high color rendering properties. Further, by adjusting the phosphor type, blending amount, and / or phosphor resin thickness (optical path length) in each light emitting unit group, white light with a suppressed deviation from black body radiation at a desired color temperature is obtained. be able to.

Next, another example of the light emitting device according to one embodiment of the present invention will be described. In this example, a near ultraviolet LED chip is used instead of the blue LED chip. As the near-ultraviolet LED chip, any existing one can be used including GaN-based and In _x Ga _1-x N-based.

As a blue phosphor that emits blue light when excited by near-ultraviolet light, a BAM phosphor such as BaMgAl ₁₀ O ₁₇ : Eu ²⁺ is used, but is not particularly limited. For example, (Sr, Ba) ₂ SiO ₄ : Eu ²⁺ is used as the green phosphor that emits green light when excited by near ultraviolet light, but is not particularly limited. Examples of red phosphors that emit red light when excited by near ultraviolet light include oxysulfide phosphors such as La ₂ O ₃ S: Eu ³⁺ phosphors, nitride phosphors (for example, CaAlSiN ₃ : Eu), and the like. Alternatively, germanate-based phosphors such as manganese-activated magnesium fluorogermanate (2.5MgO · MgF ₂ : Mn ⁴⁺ ) are used, but are not particularly limited. (Y, Gd) ₃ Al ₅ O ₁₂ : Ce or the like is used as a phosphor that emits yellow light when excited by near ultraviolet light, but is not particularly limited. For example, a blue phosphor having an emission intensity peak in the wavelength range of 420 nm to 480 nm when excited by the near ultraviolet light, a green phosphor having an emission peak in the wavelength range of 500 nm to less than 540 nm, and a wavelength of 540 nm to less than 590 nm. A yellow phosphor having a light emission peak in the range, a red phosphor having a light emission peak in a wavelength range of 590 nm to less than 650 nm, and the like can be used. The types and blending ratios of the phosphors in each light emitting part group emitting each monochromatic light are such that, in each light emitting part group, the emission intensity at the peak wavelength of near ultraviolet light is 35% or less of the emission intensity at the peak wavelength of the phosphor. Adjustments are made so that a certain spectral spectrum is obtained, the average color rendering index Ra of light emission from the light emitting device is high, and high light emission efficiency is obtained, and white at a desired color temperature is obtained. Is done.

  Also in the light emitting device 1 of this example, the light emitting unit group is configured to have a spectral spectrum in which the emission intensity at the peak wavelength of near-ultraviolet light is 35% or less of the emission intensity at the peak wavelength of the phosphor. From the light emitting unit group including the phosphor, it is possible to obtain a light emission color with little color mixing of near ultraviolet light, that is, a light emission color of the phosphor or a light emission color close thereto. Therefore, it is possible to easily obtain light emission having a desired single light color or a desired chromaticity. Further, it is possible to obtain light emission with high luminous efficiency and desired chromaticity while maintaining high color rendering properties. Furthermore, by adjusting the phosphor type, blending amount and / or phosphor resin thickness (optical path length) in each light emitting unit group, white light in which deviation from black body radiation at a desired color temperature is suppressed is obtained. be able to.

  Next, light emission from the light emitting devices according to these embodiments will be further described with reference to the CIE chromaticity diagram. FIG. 7 is a diagram showing the chromaticity (variable color gamut) of light emission of the light emitting device according to these embodiments. Here, a case where a blue LED chip is used will be described. The light emitting device 1 includes a light emitting unit group 2G that emits green light when excited by blue light, a light emitting unit group 2Y that emits yellow light, a light emitting unit group 2R that emits red light, and a light emitting unit that emits blue light. And a group 2B. Since the light emitting device according to this embodiment can obtain blue light, green light, yellow light, and red light, the chromaticity in the range shown in FIG. 7 can be obtained, and can be varied within this range. is there. This will be described in detail below.

  In the chromaticity diagram of FIG. 7, the chromaticity of blue light emitted from the blue LED chip is a point A, and the chromaticity of light emitted from a green phosphor having a dominant wavelength of 525 nm is a point B, and the dominant wavelength is 565 nm. The chromaticity of light emitted from the yellow phosphor having the same is represented by a point C, and the chromaticity of light emitted from a red phosphor having a dominant wavelength of 650 nm is represented by a point D. The locus of black body radiation (black body locus) is represented by a curve a. Further, a desired color temperature (for example, 5000 K) is represented by a point E on the black body locus a, and a deviation in the color temperature is represented by a straight line including the point E. Similarly, another desired color temperature on the black body locus a and a deviation in the color temperature are represented by points on the black body locus a and straight lines including the points.

  Light emission from the green light emitting unit group 2G is chromaticity of light obtained by adding green light emission from the green phosphor and blue light from the blue LED chip. On the chromaticity diagram shown in FIG. And an arbitrary point (not shown) on a straight line connecting point B and point B. This point can be moved by adjusting the blending amount of the green phosphor. For example, it can be moved to the point B side by increasing the blending amount of the green phosphor. Similarly, light emitted from the red light emitting unit group 2R can be moved to an arbitrary point (not shown) on the straight line connecting the points A and D by adjusting the blending amount of the red phosphor. Here, by adjusting the blending amount of the green phosphor and the blending amount of the red phosphor, it is possible to obtain the chromaticity of an arbitrary point in the triangle formed by connecting the points A, B, and D. become. Further, the light emitted from the yellow light emitting unit group 2Y is similarly moved to any point (not shown) on the straight line connecting the points A and C by adjusting the blending amount of the yellow phosphor. Therefore, by adjusting the blending amount of the green phosphor, the red phosphor, and the yellow phosphor, the chromaticity of an arbitrary point within the square connecting the points A, B, C, and D can be obtained. Can do. That is, the square is adjusted so that white light with suppressed color deviation at a desired color temperature can be obtained. The light emission from the light emitting unit group including each phosphor is adjusted not only by the blending amount of each phosphor, but also by adjusting the thickness (optical path length) of the phosphor resin layer containing each color phosphor. Can be done.

  In addition, each light emitting unit group is set so that current can be supplied from a power source through an electric wire (not shown) via the power supply pattern units 3c and 3d so that each light emitting unit individually emits monochromatic light, and is supplied from the power source. By adjusting the current to be adjusted, the electric energy applied to the blue LED chip of each light emitting unit group is adjusted to adjust the light emission of the LED, thereby obtaining light emission of a desired chromaticity. Since the color can be changed by adjusting the current supplied from the power source, a variable color light emitting device can be provided. In addition, a lineup of variable colors is possible within a range according to the application, and it can also be used as a display device.

  In addition, although the light-emitting device 1 of embodiment described above is a COB module, the light-emitting device which has arrange | positioned the light emission part 10 as shown in FIG. 8, for example in matrix form on one plane may be sufficient, for example. Although the luminance is lower than that of the COB module, the same effect can be obtained. In FIG. 8, 2 is a blue LED chip or a near-ultraviolet LED chip, and this blue LED chip or near-ultraviolet LED chip 2 is mounted on a circuit pattern 53 provided on a substrate 51 via an electrical insulating layer 52. Has been. The circuit pattern 53 is formed on the anode-side and cathode-side circuit patterns 53a and 53b, and the blue LED chip or near-ultraviolet LED chip 2 has the bottom electrode mounted on one of the circuit patterns 53a and 53b, for example, on the anode-side circuit pattern 53a. On the other hand, the upper surface electrode is electrically connected to the other of the circuit patterns 53 a and 53 b, for example, the cathode side circuit pattern 53 b by a bonding wire 54. A frame 56 for forming a recess 55 is provided on the substrate 51, and the blue LED chip or the near-ultraviolet LED chip 2 is disposed in the recess 55. And in the recessed part 55 by which the blue LED chip or the near ultraviolet LED chip 2 is arrange | positioned, the fluorescent substance containing resin which mixed and disperse | distributed fluorescent substance in transparent resin or transparent resin is apply | coated and filled, and a transparent resin layer or A phosphor-containing resin layer 9 is provided.

  Next, examples of the present invention will be described.

Example A COB package was prepared in which LED chips were mounted in vertical and horizontal directions of 8 by 8 in an area of about 5 cm square. The COB package has a system in which the vertical line chips can be individually lit. As the LED chip, a blue LED chip emitting light having a wavelength of 460 nm was used.

  For yellow light, a yellow phosphor having a peak wavelength at a wavelength of 565 nm (silicate, particle size 15 μm) was blended in a two-pack type transparent silicone resin at 30 wt%, 35 wt% and 40 wt% and completely dispersed. For green light, a green phosphor having a peak wavelength at a wavelength of 525 nm was blended in a two-pack type transparent silicone resin at about 35% by weight and completely dispersed. For red light, a red phosphor having a peak wavelength at a wavelength of 650 nm was blended in a two-pack type transparent silicone resin at about 30% by weight and completely dispersed. For blue light, only a two-pack type transparent silicone resin was used without containing a phosphor.

  The various phosphor-containing silicone resins and phosphor-free silicone resins thus obtained were sequentially applied and cured for each line to form a phosphor-containing resin layer and a transparent resin layer. As shown in FIG. 4, each color was separately applied in the order of blue, yellow, green, and red from the left so that green and yellow are located in the center in consideration of visibility. It should be noted that a wall for coating differently was provided on the substrate of the COB package. The optical path length of the phosphor-containing resin layer (the thickness of the phosphor-containing resin layer on the light extraction side from the upper surface of the LED chip) was 1.0 mm.

  In the light emitting device thus obtained, only the blue LED chip of the line coated with the resin layer containing the yellow phosphor was turned on to emit light, and the spectrum was measured. The result is as shown in FIG. 9, and the ratio of the emission intensity at the peak wavelength of blue light to the emission intensity at the peak wavelength of the yellow phosphor is about 20% when 30 wt% of the yellow phosphor is contained. In the case of containing 35% by weight of the yellow phosphor, it was about 5%, and in the case of containing 40% by weight of the yellow phosphor, it was about 1%.

  In addition, the blue LED chip of the line coated with the resin layer containing the green phosphor and the blue LED chip of the line coated with the resin layer containing the red phosphor were individually turned on to emit light, and the spectrum was measured. However, the ratio of the emission intensity at the peak wavelength of blue light to the emission intensity at each peak wavelength of the green phosphor and the red phosphor was 35% or less.

  Thereafter, all the blue LED chips were turned on, and the chromaticity of the obtained white light was examined. As a result, white light having a substantially desired chromaticity was obtained.

It is a top view which shows an example of the light-emitting device concerning one Embodiment of this invention. It is the II-II sectional view taken on the line of FIG. It is a figure which shows typically an example of the light-emitting device which has arrange | positioned the light emission part group of 3 groups in the shape of a line. It is a figure which shows typically an example of the light-emitting device which has arrange | positioned the light emission part group of 4 groups in the shape of a line. It is a figure which shows typically an example of the light-emitting device which has arrange | positioned four light emission part groups in parallel at 2 steps | paragraphs of lines, respectively. It is a figure which shows typically an example of the light-emitting device which has arrange | positioned each light emission part group of 4 groups in matrix form. It is a figure which shows typically the chromaticity (variable color gamut) of light emission of the light-emitting device concerning one Embodiment of this invention. It is sectional drawing which shows the principal part structure of the light-emitting device concerning other embodiment of this invention. It is a figure which shows the distribution spectrum measured in the Example of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Light emitting device, 2 ... Blue LED chip, 2B ... Blue light emission part group, 2G ... Green light emission part group, 2R ... Red light emission part group, 2Y ... Yellow light emission part group, 4 ... Board | substrate, 9 ... Transparent resin layer or fluorescence Body-containing resin layer, 9B ... transparent resin layer, 9G ... green phosphor resin layer, 9R ... red phosphor resin layer, 9Y ... yellow phosphor resin layer.

Claims (9)

  A blue light emitting element that emits blue light and a phosphor layer that is coated on the blue light emitting element and includes a phosphor that is excited by the blue light and emits monochromatic light other than blue light. A light emitting device having a spectral spectrum in which an emission intensity at a peak wavelength is 35% or less of an emission intensity at a peak wavelength of the phosphor. A blue light emitting element emitting blue light and a first light emitting part having a transparent resin layer coated on the blue light emitting element;
A blue light emitting element that emits blue light, and a phosphor that is coated on the blue light emitting element and that is excited by the blue light and emits monochromatic light other than blue light, and the emission intensity at the peak wavelength of the blue light is the fluorescence A second light emitting part having a spectral spectrum which is 35% or less of the emission intensity at the peak wavelength of the body;
A light-emitting device comprising:   The second light emitting unit includes a green light emitting unit including a green light emitting phosphor that emits green light when excited by the blue light, and a yellow light emitting that includes a yellow light emitting phosphor that emits yellow light when excited by the blue light. The light emitting device according to claim 2, further comprising: a red light emitting portion including a red light emitting phosphor that emits red light when excited by the blue light.   A near-ultraviolet light emitting element that emits near-ultraviolet light; and a phosphor layer that is coated on the ultraviolet light-emitting element and includes a phosphor that emits monochromatic light when excited by the near-ultraviolet light. A light emitting device having a spectral spectrum in which an emission intensity at a peak wavelength is 35% or less of an emission intensity at a peak wavelength of the phosphor. A near-ultraviolet light emitting element that emits near-ultraviolet light, and a phosphor that is coated on the near-ultraviolet light-emitting element and is excited by the near-ultraviolet light to emit blue light, and the emission intensity at the peak wavelength of the near-ultraviolet light is A blue light-emitting portion having a spectral spectrum which is 35% or less of the emission intensity at the peak wavelength of the phosphor;
A near-ultraviolet light emitting element that emits near-ultraviolet light, and a phosphor that is coated on the near-ultraviolet light-emitting element and is excited by the near-ultraviolet light to emit green light, and the emission intensity at the peak wavelength of the near-ultraviolet light is A green light emitting part having a spectral spectrum which is 35% or less of the emission intensity at the peak wavelength of the phosphor;
A near-ultraviolet light-emitting element that emits near-ultraviolet light and a phosphor that is coated on the near-ultraviolet light-emitting element and is excited by the near-ultraviolet light to emit yellow light, and the emission intensity at the peak wavelength of the near-ultraviolet light is A yellow light emitting part having a spectral spectrum which is 35% or less of the emission intensity at the peak wavelength of the phosphor;
A near-ultraviolet light emitting element that emits near-ultraviolet light, and a phosphor that is coated on the near-ultraviolet light-emitting element and is excited by the near-ultraviolet light to emit red light, and the emission intensity at the peak wavelength of the near-ultraviolet light is A red light emitting part having a spectral spectrum which is 35% or less of the emission intensity at the peak wavelength of the phosphor;
A light-emitting device comprising:   The light emitting device according to claim 2, wherein the light emitting units are arranged in a predetermined arrangement pattern on the substrate.   The light emitting device according to claim 6, wherein the predetermined arrangement pattern is a line shape or a matrix shape.   The light-emitting device according to claim 2, wherein white light is emitted by light from the light-emitting unit.   The light-emitting device according to claim 2, wherein the light-emitting device emits light having a variable color gamut adjusted by light from the light-emitting unit.

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