JP2007116107A - Light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device comprising a blue light emitting element in which angular color difference is reduced. <P>SOLUTION: The light emitting device 1 comprises a substrate 20 provided with a recess 21 having a depth D1 of 0.4-0.8 mm in the surface, a light emitting diode chip 50 arranged in the recess 21 and emitting blue light, and a phosphor layer 70 arranged on the light emitting diode chip 50 and containing a phosphor 72 which is excited with blue light emitted from the light emitting diode chip 50 to emit yellow light. Angular color difference (Δuv) is 0.012 or less for the observation angle in the range of 0°-70°. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light emitting device including a light emitting element that emits blue light.

  Light-emitting diodes are rapidly expanding in various fields such as backlights for liquid crystal displays, mobile phones, information terminals, and indoor / outdoor advertisements. In addition, light emitting diodes have long life and high reliability, and have features such as low power consumption, impact resistance, high purity display color, lightness, thinness, and so on. Application is also being attempted. When such a light emitting diode is applied to various uses, it is important to obtain white light.

  As a typical method for realizing white light with a light emitting diode, (1) a method using three light emitting diode chips for emitting red, green and blue colors, and (2) a light emitting diode chip for emitting blue light with yellow or There are three methods: a method of combining a phosphor that emits orange light, and a method of combining a light emitting diode chip that emits ultraviolet light and a three-color mixed phosphor of red, green, and blue. Among these, generally, from the viewpoint of luminance characteristics, the method (2) of combining a light emitting diode chip that emits blue light and a phosphor that emits yellow or orange light has been widely put into practical use.

  The structure of the light emitting diode to which the methods (2) and (3) described above are applied is as follows. A transparent resin mixed with a phosphor emitting a desired color is poured into a cup-shaped frame equipped with a light emitting diode chip. In general, a structure in which a phosphor layer containing phosphor is formed by solidifying (see, for example, Patent Document 1). In such a light emitting diode chip, improvement of light extraction efficiency based on the electrode shape of a light emitting diode chip such as a flip chip, light distribution control by examining the chip shape, etc. are being advanced, and the amount of light to the front of the chip is It tends to increase.

  On the other hand, in addition to industrial applications that have been developed so far, lighting applications that are expected to develop rapidly are becoming increasingly multi-frame in anticipation of illuminance. Naturally, as the quality, it is required to reduce color variation between frames and color difference for each observation angle in each frame (hereinafter referred to as “angle color difference”).

A technique is disclosed in which a reflective frame having a through hole is arranged on a substrate, and a light emitting diode is arranged in the through hole (see, for example, Patent Document 2). Here, the through hole has a first hole portion having a depth of 0.8 mm, but a second hole portion communicating with the first hole portion is formed below the first hole portion. Therefore, it is considered that the entire depth of the through hole exceeds 0.8 mm.
JP 2001-148516 A Japanese Patent No. 3268910

  The present invention has been made to solve the above problems. That is, an object is to provide a light emitting device with reduced angular color difference.

  The invention according to claim 1 is a substrate provided with a recess having a depth of 0.4 to 0.8 mm on the surface; a light emitting element disposed in the recess and emitting blue light; and on the light emitting element And a phosphor layer containing a yellow light-emitting phosphor that emits yellow light when excited by blue light emitted from the light-emitting element, and an angle color difference (Δuv) when the observation angle is greater than 0 degree and less than or equal to 70 degrees Is a light emitting device characterized in that the light emitting device is 0.012 or less.

  The invention according to claim 2 is a substrate having a recess having a depth of 0.4 to 0.8 mm on the surface; a light emitting element disposed in the recess and emitting blue light; and on the light emitting element And a phosphor layer containing a yellow light-emitting phosphor that emits yellow light when excited by blue light emitted from the light-emitting element, and is formed by an extended surface of the bottom surface of the recess and an inner surface of the recess The light emitting device is characterized in that the angle is not less than 63 degrees and not more than 90 degrees.

  Invention of Claim 3 is the light-emitting device of Claim 1 or 2, Comprising: The diameter of the opening end surface of the said recessed part is 3.5 mm or more, The diameter of the bottom face of the said recessed part is 3.0 mm or more A light emitting device characterized by the above.

  Invention of Claim 4 is the light-emitting device of Claim 1 or 2, Comprising: The diameter of the opening end surface of the said recessed part is 3.5 mm or more and 5.0 mm or less, and the diameter of the bottom face of the said recessed part is 3.0 mm 3. The light emitting device according to claim 1, wherein the light emitting device is 4.0 mm or less.

  According to invention of Claim 1, since the depth of the recessed part of a base material shall be 0.4-0.8 mm, the light path difference can be reduced and the light-emitting device with which the angle color difference was reduced can be provided. it can. In addition, since the angular color difference (Δuv) when the observation angle is greater than 0 degree and equal to or less than 70 degrees is 0.012 or less, a light-emitting device with reduced angle color difference can be provided.

  According to invention of Claim 2, since the depth of the recessed part of a base material shall be 0.4-0.8 mm, the optical path difference can be reduced and the light-emitting device with which the angle color difference was reduced is provided. Can do. In addition, since the angle formed by the extended surface of the bottom surface of the concave portion and the inner side surface of the concave portion is not less than 63 degrees and not more than 90 degrees, it is possible to secure an amount of yellow light emitting phosphors of a predetermined amount or more, It is possible to provide a light-emitting device that can be easily adjusted and suppresses a decrease in light-emitting efficiency.

  When the angle formed between the extended surface of the bottom surface of the recess and the inner surface of the recess exceeds 90 degrees, the shape of the recess becomes a so-called flask shape with a narrow opening, and the inner surface of the recess It faces the element at a predetermined angle. Therefore, a part of the light emitted from the entire device is reflected by the inner side surface, and the total amount of light emitted from the entire device is reduced.

  According to the invention described in claim 3, since the diameter of the opening end face of the recess is 3.5 mm or more and the diameter of the bottom surface of the recess is 3.0 mm or more, the amount of the yellow light-emitting phosphor more than a predetermined amount is ensured. Thus, it is possible to provide a light emitting device that can easily adjust the color temperature and suppress a decrease in light emission efficiency.

  According to invention of Claim 4, since the diameter of the opening end surface of a recessed part is 3.5 mm or more and 5.0 mm or less, and the diameter of the bottom face of a recessed part is 3.0 mm or more and 4.0 mm or less, It is possible to provide a light-emitting device that can secure an amount of a yellow light-emitting phosphor of a predetermined amount or more, can easily adjust the color temperature, and can suppress a decrease in light emission efficiency.

(First embodiment)
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the same or equivalent member in several attached drawing. FIG. 1 is a plan view of the light emitting device according to the present embodiment, and FIG. 2 is a longitudinal sectional view of the light emitting device according to the present embodiment. FIG. 3 is an enlarged longitudinal sectional view of the light emitting unit according to the present embodiment, and FIGS. 4A and 4B are schematic diagrams showing the relationship between the depth of the recess and the optical path difference according to the present embodiment. FIG.

  As shown in FIGS. 1 to 3, the light emitting device 1 includes a plurality of light emitting units 10 arranged in a row as in the example shown in FIG. 1, for example. In addition, the light emission part 10 may be arrange | positioned in the matrix form, such as 3 rows 3 columns, for example.

  The base material 20 which comprises the light emission part 10 equips the surface with the recessed part 21 comprised from the opening end surface 21a, the bottom face 21b, and the inner surface 21c. The depth D1 (distance from the opening end surface 21a to the bottom surface 21b) of the recess 21 is 0.4 to 0.8 mm, preferably 0.4 to 0.5 mm.

  In addition, an angle α (hereinafter referred to as “inner side surface angle”) formed by the extended surface 21d extending the bottom surface 21b and the inner side surface 21c is 63 degrees or more and 90 degrees or less. Furthermore, the diameter D2 of the opening end surface 21a is 3.5 mm or more and 5.0 mm, and the diameter D3 of the bottom surface 21b is 3.0 mm or more and 4.0 mm or less. The diameter D3 of the bottom surface 21b is preferably equal to or smaller than the diameter D2 of the opening end surface 21a.

  The base material 20 includes a substrate 30 and a frame member 40 that covers the surface and side surfaces of the substrate 30. The frame member 40 only needs to be disposed on at least the substrate 30, and does not need to cover the side surface of the substrate 30.

  The substrate 30 is a flat substrate made of aluminum (Al), nickel (Ni), glass epoxy, or the like having heat dissipation and rigidity, and is an integrated substrate in which the substrates of the plurality of light emitting units 10 are integrally connected. The substrate 30 has an electrical insulating layer 31 and a circuit pattern 32 disposed on the electrical insulating layer 31 on the surface.

  As shown in FIG. 3, the circuit pattern 32 is formed on the cathode side and anode side circuit patterns (wiring patterns) 32a and 32b by an alloy of Cu and Ni, Au, Ag, or the like for each light emitting unit 10. A light emitting diode chip 50 to be described later is mounted on the circuit pattern 32.

  The frame member 40 is formed with a frustoconical opening 41 that gradually expands concentrically as the distance from the surface of the substrate 30 increases. By arranging the frame member 40 on the substrate 30, the opening 41 will be described later. The opening end face 41b is closed and the recess 21 is formed. Note that the recess 21 can be formed on the surface of the substrate 30 without using the frame member 40.

  In the present embodiment, since the recess 21 is formed by combining the substrate 30 and the frame member 40 having the opening 41, the opening end surface 21 a of the recess 21 corresponds to the opening end surface 41 a of the opening 41. The bottom surface 21 b corresponds to a region of the surface of the substrate 30 surrounded by the opening end surface 41 b of the opening 41, and the inner side surface 21 c of the recess 21 corresponds to the inner side surface 41 c of the opening 41.

  Such a frame member 40 is made of a synthetic resin such as PBT (polybutylene terephthalate), PPA (polyphthalamide), PC (polycarbonate) or the like.

  In the recess 21, a light emitting diode chip 50 that emits blue light as a light emitting element is disposed at a predetermined interval from the inner side surface 41 c of the opening 41. These light emitting diode chips 50 are made of, for example, a gallium nitride (GaN) based semiconductor.

  Each light emitting diode chip 50 has its bottom electrode placed on one surface of the circuit patterns 32a and 32b and electrically connected thereto, while its top electrode has a bonding wire on the other surface of the circuit patterns 32a and 32b. 60 is electrically connected.

  The recess 21 is filled (applied) with a phosphor layer 70 made of a transparent resin 71 and a yellow light-emitting phosphor 72, and the light-emitting diode chip 50 is covered with the phosphor layer 70.

  The phosphor layer 70 is obtained by adding a yellow light emitting phosphor 72 to a liquid transparent resin 71 such as a silicone resin or an epoxy resin and mixing the mixture into a dispenser, and dropping the mixture into the recess 21 from the dispenser. It is formed by coating.

  The yellow light emitting phosphor 72 is excited by blue light emitted from the light emitting diode chip 50 to emit yellow light. In order to improve color rendering properties and the like, a red light-emitting phosphor may be included in the phosphor layer 80 together with the yellow light-emitting phosphor 72.

Examples of the yellow light emitting phosphor 72 include YAG phosphors such as RE ₃ (Al, Ga) ₅ O ₁₂ : Ce phosphor (RE represents at least one selected from Y, Gd and La), AE ₂ SiO, and the like. ₄ : Silicate phosphor such as Eu phosphor (AE is an alkaline earth element such as Sr, Ba, Ca), n-UVLEDBGR, nitride phosphor, oxynitride phosphor, sialon, etc. are used. .

  In such a light emitting device 1, the electric energy applied to each light emitting unit 10 is converted into blue light by the light emitting diode chip 50, and the yellow light emitting phosphor 72 is excited by this blue light to emit yellow light and emit light. White light is obtained by mixing the blue light emitted from the diode chip 50 and the yellow light emitted from the yellow light emitting phosphor 72.

  According to the present embodiment, since the depth D1 of the recess 21 is 0.4 to 0.8 mm, there is no possibility that the bonding wire 60 is exposed from the opening end surface 21a, and the light emission whose angle color difference is sufficiently reduced. A device 1 can be provided. Specifically, according to the present embodiment, it is possible to reduce the angle color difference (Δuv) when the observation angle exceeds 0 degree and is equal to or less than 70 degrees to 0.012.

  As the angular color difference (Δuv) increases, the color temperature of white light changes according to the observation angle. In addition, the change in color temperature depends largely on the subjectivity of the observer. In general, when the angle color difference (Δuv) is reduced, the change in color temperature of white light due to the observation angle is also reduced, and the percentage of observers who feel the change in color temperature according to the observation angle is reduced even when the subjectivity of the observer is taken into consideration. . Actually, the perception of the change in color temperature of white light varies depending on the subjectivity of the observer when the angular color difference (Δuv) is in the range of 0.01 to 0.02. In such an angle color difference (Δuv), a ratio of an observer who feels that the color temperature of white light changes depending on the observation angle and an observer who does not feel a change in color temperature depends on the subjectivity of the observer. However, the angular color difference is often annoying at around 0.015 at each color temperature.

  Therefore, in the present invention, the angular color difference (Δuv) is set to 0.012 or less. In fact, in the light-emitting device of the present invention, by setting the angular color difference (Δuv) to 0.012 or less, the ratio of observers who feel the change in the color temperature of white light due to the observation angle is greatly reduced.

  The observation angle is a line connecting the observation point and the center of the surface of the phosphor layer 70 with the axis passing through the center of the surface of the phosphor layer 70 and being perpendicular to the surface of the phosphor layer 70 (0 degree). And the angle formed by the axis. Further, the angle color difference (Δuv) at the observation angle X degrees can be obtained by the following equation (1).

Δuv = {(uX−u0) ² + (vX−v0) ² } ^1/2 (1)
Here, uX and vX are u value and v value when an emission spectrum of a wavelength of 380 to 780 nm is measured at an observation angle of X degrees, and u0 and v0 are emission spectra of a wavelength of 380 to 780 nm at an observation angle of 0 degree. Are the u value and v value when. Note that the emission spectra at the observation angles X degrees and 0 degrees are measured by an instantaneous spectrophotometer at a location 300 mm away from the center of the surface of the phosphor layer 70, respectively.

  The cause of the angular color difference is that the optical path length changes depending on the observation angle. Specifically, as shown in FIGS. 4A and 4B, the optical path length b when the observation angle is X degrees is longer than the optical path length a when the observation angle is 0 degrees. The light emission of the yellow light emitting phosphor 72 is increased. Thereby, it is considered that the color temperature is lower at the observation angle X degree than at the observation angle 0 degree, and the angle color difference is generated. On the other hand, when the depth D1 of the concave portion 21 is shallower (FIG. 4A), the optical path length when the observation angle is 0 degree than when the depth D1 of the concave portion 21 is deeper (FIG. 4B). The difference (optical path difference) between a and the optical path length b when the observation angle is X degrees can be reduced.

  Therefore, if the depth D1 of the recess 21 is reduced, the angular color difference can be reduced. However, if the depth D1 of the recess 21 is less than 0.4 mm, the bonding wire 60 may be exposed from the opening end surface 21a. On the other hand, if the depth D1 of the recess 21 exceeds 0.8 mm, the angular color difference cannot be sufficiently reduced. For this reason, in the present embodiment, the depth D1 of the recess 21 is defined as 0.4 mm to 0.8 mm. Therefore, according to the present embodiment, it is possible to provide the light emitting device 1 in which the bonding wire 60 is not exposed from the opening end surface 21a and the angular color difference is sufficiently reduced.

  When the depth D1 of the concave portion 21 is reduced, the volume of the concave portion 21 is reduced, so that the amount of the yellow light-emitting phosphor 72 in the concave portion 21 is reduced and the yellow light is reduced. As a result, it is difficult to adjust the color temperature (particularly, adjustment of a low color temperature such as 4000K, 3000K, 2800K, etc.) and the light emission efficiency may be reduced. For this reason, when the depth D1 of the recess 21 is set to 0.4 mm to 0.8 mm, it is desirable to secure an amount of the yellow light-emitting phosphor 72 that is a predetermined amount or more.

  Here, if the angle α of the inner side surface 21c is increased while maintaining the size of the opening end surface 21a, the volume of the concave portion 21 can be prevented from decreasing. Can be secured. However, if the angle α of the inner surface 21c is less than 63 degrees, the volume of the recess 21 cannot be increased sufficiently. For this reason, in the present embodiment, the angle α of the inner surface 21c is defined as 63 degrees or more. Therefore, according to the present embodiment, since the amount of the yellow light-emitting phosphor 72 that is equal to or greater than a predetermined amount can be ensured, the light-emitting device 1 that can easily adjust the color temperature and suppress the decrease in light emission efficiency is provided. can do.

  When the angle formed between the extended surface of the bottom surface of the recess and the inner surface of the recess exceeds 90 degrees, the shape of the recess becomes a so-called flask shape with a narrow opening, and the inner surface of the recess It faces the element at a predetermined angle. Therefore, a part of the light emitted from the entire device is reflected by the inner side surface, and the total amount of light emitted from the entire device is reduced.

  In addition, even when the opening end surface 21a and the bottom surface 21b are enlarged, a decrease in the volume of the recess 21 can be suppressed, so that the amount of the yellow light-emitting phosphor 72 that is a predetermined amount or more can be ensured. . However, if the diameter of the opening end surface 21a is less than 3.5 mm and the diameter of the bottom surface 21b is less than 3.0 mm, the volume of the recess 21 cannot be increased sufficiently. For this reason, in the present embodiment, the diameter of the opening end face 21a is set to 3.5 mm or more, and the diameter of the bottom face 21b is specified to be 3.0 mm or more. Therefore, according to the present embodiment, since the amount of the yellow light-emitting phosphor 72 that is equal to or greater than a predetermined amount can be ensured, the light-emitting device 1 that can easily adjust the color temperature and suppress the decrease in light emission efficiency is provided. can do.

  The spread of yellow light emitted from the yellow light emitting phosphor 72 is larger than the spread of blue light emitted from the light emitting element (light emitting diode chip 50). Therefore, if the diameter of the opening end surface 21a becomes too large, the blue light and the yellow light may not sufficiently overlap, and the target white light may not be obtained. Therefore, in the present embodiment (the present invention), it is preferable that the upper limit of the diameter of the opening end surface 21a is 5.0 mm. Thereby, the above-mentioned problem can be avoided.

  In addition, the upper limit of the diameter of the bottom surface 21b is preferably set to 4.0 mm from the viewpoint of setting the angle α to 63 degrees or more and securing the amount of the yellow light-emitting phosphor 72.

(Second Embodiment)
The second embodiment of the present invention will be described below with reference to the accompanying drawings. In the present embodiment, an example in which the phosphor layer is formed in a sheet shape and the phosphor layer is disposed on the frame member will be described. In addition, in the accompanying drawings, the same or equivalent members as those described in the first embodiment are denoted by the same reference numerals, and overlap with the contents described in the first embodiment. The contents to be omitted shall be omitted. FIG. 5 is an enlarged longitudinal sectional view of the light emitting unit according to the present embodiment.

  As shown in FIG. 5, a sheet-like phosphor layer 70 is formed on the frame member 40 so as to cover the recess 21. In addition, a transparent resin layer 80 is filled (applied) in the recess 21, and the light emitting diode chip 50 is covered with the transparent resin layer 80.

  In the present embodiment, the phosphor layer 70 is formed on the frame member 40, and the transparent resin layer 80 is formed in the recess 21. Other configurations and dimensions are the same as those in the first embodiment. Therefore, the same effects as those of the first embodiment can be obtained.

(Third embodiment)
6 and 7 show a light emitting device for forming an LED package according to the third embodiment of the present invention. 6 is a plan view of the light emitting device, and FIG. 7 is a longitudinal sectional view of the light emitting device shown in FIG. 6 taken along line F2. 6 and 7 relating to the present embodiment, the same reference numerals are used for the same constituent elements as those in the drawings relating to the above-described embodiment.

  The light emitting device 1 shown in FIGS. 6 and 7 includes a package substrate such as a device substrate 30, a reflective layer 81, a circuit pattern 32, and preferably a plurality of LED chips such as a semiconductor light emitting element 50, an adhesive layer 82, and a reflector 84. And a sealing member 71 and a light diffusing member 83.

  The device substrate 30 is made of a flat plate made of a metal or an insulating material such as a synthetic resin, and has a predetermined shape such as a rectangular shape in order to obtain a light emitting area required for the light emitting device 1. When the device substrate 30 is made of a synthetic resin, it can be formed of, for example, an epoxy resin containing glass powder. When the device substrate 30 is made of metal, the heat radiation from the back surface of the device substrate 30 is improved, the temperature of each part of the device substrate 30 can be made uniform, and the semiconductor light emitting element 50 that emits light in the same wavelength range. The variation in the emission color can be suppressed. In addition, as a metal material which has such an effect, the material excellent in the thermal conductivity of 10 W / m * K or more, specifically aluminum, or its alloy can be illustrated.

  The reflective layer 81 has a size that allows a predetermined number of semiconductor light emitting elements 50 to be disposed, and is attached to the entire surface of the device substrate 30, for example. The reflective layer 81 can be made of a white insulating material having a reflectance of 85% or more in a wavelength region of 400 nm 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 by impregnating a sheet base material with a thermosetting resin mixed with a white powder such as aluminum oxide. The reflective layer 81 is bonded to the entire surface of the device substrate 30 by its own adhesiveness.

  The circuit pattern 32 is bonded to the surface of the reflective layer 81 opposite to the surface to which the device substrate 30 is bonded as an energization element to each semiconductor light emitting element 50. For example, in order to connect the respective semiconductor light emitting elements 50 in series, the circuit pattern 32 is formed in two rows scattered at predetermined intervals in the longitudinal direction of the device substrate 30 and the reflective layer 81 as shown in FIG. Yes. An end side circuit pattern 32a located on one end side of one circuit pattern 32 row is integrally formed with a power feeding pattern portion 32c. Similarly, an end side located on one end side of the other circuit pattern 32 row The circuit pattern 32a is integrally formed with a power feeding pattern portion 32d.

  The power feeding pattern portions 32 c and 32 d are provided side by side at one end in the longitudinal direction of the reflective layer 81, and are separated from each other and insulated by the reflective layer 81. Electric wires (not shown) reaching the power source are individually connected to the power supply pattern portions 32c and 32d by soldering or the like.

  The circuit pattern 32 is formed by the procedure described below. First, a reflective layer 81 made of a prepreg impregnated with the uncured thermosetting resin is pasted on the device substrate 30, and then a copper foil of the same size is pasted on the reflective layer 81. Next, the laminated body thus obtained is heated and pressurized to cure the thermosetting resin, whereby the device substrate 30 and the copper foil are pressed against the reflective layer 81 to complete the adhesion. Next, a resist layer is provided on the copper foil, and after etching the copper foil, the remaining resist layer is removed to form the circuit pattern 32. The thickness of the circuit pattern 32 made of copper foil is, for example, 35 μm.

  Each semiconductor light emitting element 50 is formed of, for example, a double wire type LED chip using a nitride semiconductor, and is formed by laminating a semiconductor light emitting layer 50a on one surface of an element substrate 50b having translucency as shown in FIG. ing. The element substrate 11 is made of, for example, a sapphire substrate. The element substrate 50b is thicker than the circuit pattern 32, for example, 90 μm.

  The semiconductor light emitting layer 50a is formed by sequentially stacking a buffer layer, an n-type semiconductor layer, a light emitting layer, a p-type cladding layer, and a P-type semiconductor layer on the back surface of the element substrate 50b. The light emitting layer has a quantum well structure in which barrier layers and tungsten layers are alternately stacked. An n-side electrode is provided on the n-type semiconductor layer, and a p-side electrode is also provided on the p-type semiconductor layer. The semiconductor light emitting layer 50a does not have a reflective film, and can emit light in both thickness directions.

  As shown in FIG. 6, each semiconductor light emitting element 50 is disposed between circuit patterns 32 adjacent to each other in the longitudinal direction of the device substrate 30, and is bonded to the same surface of the white reflective layer 81 by an adhesive layer 82. . Specifically, the other surface parallel to one surface of the element substrate 50 b on which the semiconductor light emitting layer 50 a is laminated is bonded to the reflective layer 81 by the adhesive layer 82. By this adhesion, the circuit pattern 32 and the semiconductor light emitting element 50 are arranged in a straight line on the same surface of the reflective layer 81, so that the side surface of the semiconductor light emitting element 50 positioned in this arrangement direction and the circuit pattern 32 are close to each other. It is provided to do.

  The thickness of the adhesive layer 82 can be set to 100 μm to 500 μm, for example. For the adhesive layer 82, for example, a light-transmitting adhesive having a thickness of 100 μm or more and a light transmittance of 70% or more, for example, a silicone resin-based adhesive can be suitably used.

  As shown in FIG. 2, the electrodes of each semiconductor light emitting element 50 and the circuit pattern 32 disposed close to both sides of the semiconductor light emitting element 50 are connected by bonding wires 60 provided by wire bonding. Furthermore, the end side circuit patterns 32b positioned on the other end side of the two rows of circuit patterns 32 are also connected by bonding wires 60 (see FIG. 1) provided by wire bonding. Therefore, in the present embodiment, the semiconductor light emitting elements 50 are connected in series.

  The surface light source of the light emitting device 1 is formed by the device substrate 30, the reflective layer 81, the circuit pattern 32, each semiconductor light emitting element 50, the adhesive layer 82, and the bonding wire 60.

  The reflector 84 is not provided individually for each one or several semiconductor light emitting elements 5 but is a single one surrounding all the semiconductor light emitting elements 50 on the reflective layer 81, and is a frame, for example, FIG. The semiconductor light emitting element 50 is disposed in a recess 21 formed by the frame. As shown in FIG. 7, the concave portion 21 has an open end surface 21a, a bottom surface 21b, and an inner side surface 21c. The reflector 84 is bonded to the reflective layer 81, and the plurality of semiconductor light emitting elements 50 and the circuit pattern 32 are housed therein, and the pair of power feeding pattern portions 32 c and 32 d are positioned outside the reflector 84. ing.

The reflector 84 can be formed of, for example, a synthetic resin, and its inner peripheral surface is a reflective surface. The reflective surface of the reflector 84 can be formed by depositing or plating a metal material having a high reflectance such as Al or Ni, or by applying a white paint having a high visible light reflectance. Alternatively, white powder can be mixed into the molding material of the reflector 84 to make the reflector 84 itself white with high visible light reflectivity. As the white powder, a white filler such as aluminum oxide, titanium oxide, magnesium oxide or barium sulfate can be used.
Note that it is desirable to form the reflecting surface of the reflector 84 so as to gradually open in the irradiation direction of the light emitting device 1.

  The sealing member 71 is injected into the concave portion 21 of the reflector 84 and solidified so as to embed each semiconductor light emitting element 50, the bonding wire 16, and the like. The sealing member 71 is made of a translucent material such as a transparent silicone resin or transparent glass as in the above embodiment. The yellow light emitting phosphor 72 is mixed in the sealing member 71, and the phosphor layer 70 is formed by the sealing member 71 and the yellow light emitting phosphor 72. The yellow light-emitting phosphor 72 is uniformly dispersed in the sealing member 71 as shown in the figure.

  Also in the present embodiment, the blue light emitted from the semiconductor light emitting element 50 and the yellow light of the yellow light emitting phosphor 72 are mixed to form white light. However, since the depth D1 of the recess 21 is set to 0.4 to 0.8 mm, the light emitting device 1 in which the bonding wire 60 is not exposed from the opening end surface 21a and the angular color difference is sufficiently reduced is provided. Can do. Specifically, according to the present embodiment, it is possible to reduce the angle color difference (Δuv) when the observation angle exceeds 0 degree and is equal to or less than 70 degrees to 0.012.

  The angle α between the inner side surface 21c on the right side of the recess and the surface 21d extending the bottom surface of the recess 21 is defined as 63 degrees or more, and the angle between the inner side surface 21c and the extension surface 21d on the left side of the recess is approximately Since it is vertical (90 degrees), it is possible to secure an amount of the yellow light-emitting phosphor 72 that is equal to or greater than a predetermined amount, and thus it is possible to provide a light-emitting device 1 that can easily adjust the color temperature and suppress a decrease in light emission efficiency. be able to.

  The light diffusing member 83 has a difference between the transmittance of blue light of 400 nm to 480 nm and the transmittance of yellow light of 540 nm to 650 nm within 10%, and the transmittance of visible light is 90%. Those having a light diffusion performance of less than 10% can be suitably used. By using such a light diffusing member 83, the blue primary light and the yellow secondary light can be mixed by the light diffusing member 83, and white with suppressed color unevenness can be obtained.

(Examples 1 to 4 and Comparative Examples 1 and 2)
Hereinafter, Examples 1 to 4 and Comparative Examples 1 and 2 will be described. In Examples 1 to 4 and Comparative Examples 1 and 2, emission spectra with wavelengths of 380 to 780 nm at an observation angle of 50 degrees and 70 degrees were measured using light emitting devices having different recess depths, and an observation angle of 50 degrees. The angle color difference (Δuv) at 70 ° and the angle color difference (Δuv) at an observation angle of 70 ° were calculated. The light emitting devices used in Examples 1 and 2 and Comparative Example 1 are of the type in which the phosphor layer is filled in the recesses described in the first embodiment. The light-emitting device used in Comparative Example 2 was of a type in which a sheet-like phosphor layer was disposed on the recess described in the second embodiment. Moreover, the measurement conditions such as the measurement distance were the same as the conditions described in the first embodiment.

The results will be described below.

  As shown in Table 1, the angular color difference (Δuv) at the observation angles of 50 degrees and 70 degrees in Examples 1 and 2 was lower than the angular color difference (Δuv) at the observation angles of 50 degrees and 70 degrees in Comparative Example 1. Further, as shown in Table 2, the angle color difference (Δuv) at the observation angles of 50 degrees and 70 degrees in Examples 3 and 4 is lower than the angle color difference (Δuv) at the observation angles of 50 degrees and 70 degrees in Comparative Example 2. It was. From these results, it was confirmed that when the depth of the concave portion is decreased, the angular color difference is decreased.

  Further, the angle color difference (Δuv) at the observation angles of 50 degrees and 70 degrees in Examples 1 to 4 were all 0.012 or less, whereas the angle color difference (Δuv) at the observation angle of 70 degrees in Comparative Examples 1 and 2 was. Was over 0.012.

(Examples 5 to 8 and Comparative Example 3)
Hereinafter, Examples 5 to 8 and Comparative Example 3 will be described. In Examples 5 to 8 and Comparative Example 3, using light emitting devices having different angles of the inner surface of the recess, the diameter of the opening end surface of the recess, and the diameter of the bottom surface of the recess, a wavelength 380 at observation angles of 50 degrees and 70 degrees is used. An emission spectrum of ˜780 nm was measured, and an angular color difference (Δuv) at an observation angle of 50 degrees and an angular color difference (Δuv) at an observation angle of 70 degrees were calculated. Efficiency was also measured. Note that the light emitting devices used in Examples 5 to 8 and Comparative Example 3 were of the type in which the phosphor layer was filled in the recesses described in the first embodiment.

The results will be described below.

  As shown in Table 3, the angle color difference (Δuv) at the observation angles of 50 degrees and 70 degrees in Examples 5 to 8 was 0.012 or less, whereas the angle at the observation angle of 70 degrees in Comparative Example 3 The color difference (Δuv) was over 0.012. Moreover, all the efficiency of Examples 5-8 was 90% or more, and although there were some which fell from the efficiency of the comparative example 3, all were in the tolerance | permissible_range.

  The present invention is not limited to the description of the above embodiment, and the structure, material, arrangement of each member, and the like can be appropriately changed without departing from the gist of the present invention.

1 is a plan view of a light emitting device according to a first embodiment. It is a longitudinal cross-sectional view of the light-emitting device which concerns on 1st Embodiment. It is an expanded vertical sectional view of the light emission part which concerns on 1st Embodiment. (A) And (b) is the figure shown typically showing the relationship between the depth of the recessed part which concerns on 1st Embodiment, and an optical path difference. It is an expansion longitudinal cross-sectional view of the light emission part which concerns on 2nd Embodiment. It is a top view of the light-emitting device concerning a 3rd embodiment. It is a longitudinal cross-sectional view of the light-emitting device concerning 3rd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Light-emitting device, 20 ... Base material, 21 ... Recessed part, 21a ... Opening end surface, 21b ... Bottom surface, 21c ... Inner side surface, 21d ... Extension surface, 30 ... Substrate, 40 ... Frame member, 41 ... Opening, 50 ... Light emitting diode Chip: 70 ... phosphor layer, 71 ... transparent resin, 72 ... yellow light emitting phosphor.

Claims (4)

A substrate provided with a recess having a depth of 0.4 to 0.8 mm on the surface;
A light emitting element disposed in the recess and emitting blue light;
A phosphor layer that is disposed on the light emitting element and contains a yellow light emitting phosphor that emits yellow light when excited by blue light emitted from the light emitting element;
And an angle color difference (Δuv) at an observation angle of more than 0 degree and 70 degrees or less is 0.012 or less. A substrate provided with a recess having a depth of 0.4 to 0.8 mm on the surface;
A light emitting element disposed in the recess and emitting blue light;
A phosphor layer that is disposed on the light emitting element and contains a yellow light emitting phosphor that emits yellow light when excited by blue light emitted from the light emitting element;
And the angle formed by the extended surface of the bottom surface of the recess and the inner surface of the recess is 63 degrees or more and 90 degrees or less.   The light emitting device according to claim 1 or 2, wherein a diameter of an opening end surface of the concave portion is 3.5 mm or more, and a diameter of a bottom surface of the concave portion is 3.0 mm or more.   The diameter of the opening end surface of the said recessed part is 3.5 mm or more and 5.0 mm or less, The diameter of the bottom face of the said recessed part is 3.0 mm or more and 4.0 mm or less, The light-emitting device of Claim 1 or 2 characterized by the above-mentioned. .

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