JP2007207939A - Light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device 11 in which color breakup and angle color difference can be improved. <P>SOLUTION: At a position in a recess 20 opposing a light emitting diode element 13 in the vertical direction, a diffusion part 23 having a size comparable to the size of the light emitting diode element 13 when viewed in the vertical direction is provided. A phosphor layer 24 covering the light emitting diode element 13 and the diffusion part 23 is provided in the recess 20. The phosphor layer 24 has a phosphor which is excited with light from the light emitting diode element 13 to emit light. The diffusion part 23 diffuses blue light from the light emitting diode element 13 toward the vertical direction to reduce light distribution in the vertical direction and to increase light distribution in the direction inclining against the vertical direction. Color breakup and angle color difference are improved by reducing light distribution in the vertical direction and increasing light distribution in the inclining direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

  Conventionally, a light emitting device using a light emitting diode element as a light emitting element is known as a surface mount type in which a light emitting diode element is disposed on a substrate and a resin is filled and solidified so as to cover the light emitting diode element. ing.

  In order to emit white light with this type of light emitting device, a light emitting diode element that emits blue light is covered with a phosphor layer that is a resin layer in which a yellow light emitting phosphor is contained in a resin. The blue light emitted from the element is mixed with the yellow light obtained by exciting the yellow light-emitting phosphor with the blue light.

In addition, by covering the entire light emitting diode element with a diffusion layer and forming a phosphor layer on the diffusion layer, the blue light of the light emitting diode element is diffused by the diffusion layer and incident on the entire phosphor layer. Luminous efficiency is improved (for example, refer to Patent Document 1).
JP 2003-324215 A (page 3-4, FIG. 1)

  However, in a light emitting device in which a light emitting diode element is covered with a phosphor layer, the distance between the surface central portion of the phosphor layer and the light emitting diode element is closer than the distance between the surface peripheral portion of the phosphor layer and the light emitting diode element. Since the light intensity of blue light from the light emitting diode element toward the center of the surface of the phosphor layer is higher than the intensity of blue light toward the periphery of the surface of the phosphor layer, When viewed from the direction perpendicular to the surface of the body layer, the brightness of the blue light is high at the center of the surface of the phosphor layer facing the light emitting diode element in the direction perpendicular to the light, and the blue light is emitted to white light. On the other hand, there is a problem in that color fringing, which is a phenomenon in which yellow light is distributed, occurs around the surface of the phosphor layer. In addition, when viewed from a direction inclined with respect to the vertical direction of the surface of the phosphor layer, the overall color looks yellowish due to the above-described optical path length relationship and light distribution. There is a big problem.

  In addition, in the configuration in which the blue light of the light emitting diode element is diffused by the diffusion layer and incident on the entire phosphor layer, the light from the light emitting diode element toward the center of the surface of the phosphor layer is diffused, but the entire light emitting diode element is diffused. Since it is covered with the layer, the light of the light emitting diode element toward the peripheral portion of the surface of the phosphor layer is also diffused, and as a result, there is a problem that sufficient improvement cannot be obtained in the color shift and the angular color difference.

  The present invention has been made in view of these points, and an object thereof is to provide a light-emitting device that can improve color distortion and angular color difference.

  The light-emitting device according to claim 1, a substrate having a recess; a light-emitting element disposed on a bottom surface side in the recess; and a light emission at a position facing the light-emitting element in the recess in a vertical direction and viewed in a vertical direction Diffusion that is approximately the same as the size of the device and diffuses light from the light emitting device in the vertical direction to reduce light distribution in the vertical direction and increase light distribution in the tilt direction with respect to the vertical direction. And a phosphor layer that is formed so as to cover the light emitting element and the diffusion part in the recess, and has a phosphor that emits light when excited by the light of the light emitting element.

  As the substrate, a structure in which an insulating layer, a circuit pattern, and a reflector are provided on a substrate, or a resin molded product in which a lead frame is insert-molded can be used. For example, a light emitting diode element that emits blue light can be used as the light emitting element. A transparent resin containing a diffusing material can be used for the diffusing portion. The size of the diffusing portion is smaller than the diameter of the concave portion and separated from the inner surface of the concave portion, and is similar to the light emitting element and may be slightly smaller or larger than the light emitting element. A size that covers the whole is preferable. As the phosphor of the phosphor layer, for example, when white light is obtained, a yellow light-emitting phosphor that emits yellow light when excited with blue light from a light-emitting element can be used.

  The light-emitting device according to claim 2 is the light-emitting device according to claim 1, wherein the diffusion portion and the phosphor layer formed in the recess are a resin material having a viscosity higher than that of the phosphor layer and the diffusion portion is in the recess. After being formed above, the phosphor layer is formed in the recess with a resin material having a lower viscosity than the resin material of the diffusion portion.

  By using a resin material whose viscosity is higher than that of the phosphor layer, the diffusion portion is not mixed with a resin material having a viscosity lower than that of the diffusion layer of the phosphor layer, and the position and shape of the diffusion portion can be maintained. Further, a primary phosphor layer is formed around the light emitting element in the concave portion up to the height of the light emitting element, and a diffusion portion is formed on the light emitting element in that state, and then the diffusion portion in the concave portion and the primary portion are formed. A secondary phosphor layer may be further formed on the phosphor layer, or the primary phosphor layer may be omitted and a diffusion part may be formed on the light emitting element, and then a phosphor layer may be formed in the recess. May be.

  According to the light emitting device of claim 1, the vertical direction is provided by the diffusion portion provided at a position facing the light emitting element in the recess in the vertical direction and having a size approximately equal to the size of the light emitting element as viewed in the vertical direction. The light distribution toward the light emitting element is diffused to reduce the light distribution in the vertical direction, and the light distribution in the inclined direction with respect to the vertical direction can be increased, so that the color deviation and the angular color difference can be improved reliably.

  According to the light emitting device of claim 2, in addition to the effect of the light emitting device of claim 1, the diffusion portion is formed on the light emitting element in the concave portion with a resin material having a viscosity higher than that of the phosphor layer. By forming the phosphor layer in the recess with a resin material having a viscosity lower than that of the resin material, the diffusion portion and the phosphor layer can be easily formed in the recess.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of a part of the light emitting device, FIG. 2 is a front view of the light emitting device, and FIG. 3 is an explanation showing the method of forming the diffusion part and the phosphor layer in the order of (a), (b), and (c). FIGS. 4 and 4 show the light distribution of the light emitting device. FIG. 4A is a light distribution diagram using a diffusion portion, and FIG. 4B is a light distribution diagram of a comparative example using no diffusion portion.

  As shown in FIGS. 1 and 2, the light-emitting device 11 includes a light-emitting module 12, and the light-emitting module 12 is detachably attached to a light-emitting device main body (not shown) such as a fixture main body of a lighting fixture. In the light emitting module 12, light emitting diode elements (light emitting diode chips) 13, which are chip-shaped solid light emitting elements, are arranged in a matrix as a plurality of light emitting elements.

  The light emitting diode element 13 is, for example, a blue light emitting diode element made of, for example, a gallium nitride (GaN) -based semiconductor that emits blue light having an emission peak of 450 to 460 nm.

  The light emitting module 12 includes a flat substrate 14 formed of aluminum (Al), nickel (Ni), glass epoxy resin or the like having heat dissipation and rigidity, an insulating layer 15 formed on the substrate 14, and the insulating layer. The circuit pattern layer 16 is formed on the substrate 15, and the reflector 17 is formed on the substrate 14 on which the insulating layer 15 and the circuit pattern layer 16 are formed. A base body 18 is constituted by the substrate 14, the reflector 17, and the like.

  In the circuit pattern layer 16, cathode-side and anode-side circuit patterns (wiring patterns) 16a and 16b are formed of an alloy of Cu and Ni, Au, or the like for each light emitting diode element 13 position. Each light emitting diode element 13 has a bottom electrode electrically and mechanically connected to one of the circuit patterns 16a and 16b by die bonding, and a top electrode electrically connected to the other of the circuit patterns 16a and 16b by a bonding wire 19. Has been.

  The reflector 17 is formed by pouring a resin such as PBT (polybutylene terephthalate), PPA (polyphthalamide), PC (polycarbonate) or the like onto one surface of the substrate 14, and each light emitting diode element 13 emits each light emitting element. A plurality of recesses 20 that are housing portions for housing the diode elements 13 are formed. The recess 20 is formed in a truncated cone shape that gradually expands toward the opposite side with respect to the substrate 14. Around the recess 20, a lens holder portion 21 for fixing a lens (not shown) is formed concentrically.

  Each recess 20 is formed with a coating layer 22 that covers the light emitting diode element 13. The covering layer 22 includes a diffusion portion 23 disposed at a position facing the surface of the light emitting diode element 13 in the vertical direction, and a phosphor layer disposed so as to cover the light emitting diode element 13 and the diffusion portion 23. Consists of 24 and.

The diffusion part 23 is made of a thermosetting transparent resin such as translucent silicone resin or epoxy resin, potassium titanate (K ₂ TiO ₃ ), barium titanate (BaTiO ₃ ), titanium oxide (TiO ₂ ), silicon oxide. Diffusing materials such as (SiO ₂ ), zinc oxide (ZnO), alumina (Al ₂ O ₃ ), barium sulfate (BaSO ₄ ), yttrium oxide (Y ₂ O ₃ ) are blended. The size of the diffusing portion 23 is smaller than the diameter of the concave portion 20 and separated from the inner surface of the concave portion 20, and is formed to have the same size as the light emitting diode element 13. The size of the diffusing portion 23 comparable to that of the light-emitting diode element 13 may be slightly smaller or larger than the light-emitting diode element 13, but is preferably large enough to cover the entire light-emitting diode element 13 when viewed in the vertical direction. The thickness of the diffusion part 23 is uniformly formed throughout.

  The phosphor layer 24 is mainly composed of a yellow-based phosphor that receives blue light from the light-emitting diode element 13 and emits fluorescent light in yellow to a thermosetting transparent resin such as a translucent silicone resin or epoxy resin. ing. As this phosphor, a yellow phosphor is mainly used, but a red phosphor or the like is also blended.

  FIG. 3 shows a method for forming the diffusion portion 23 and the phosphor layer 24. First, as shown in FIG. 3A, the liquid transparent resin constituting the phosphor layer 24 is formed around the light emitting diode element 13 at the bottom in the recess 20 up to the height of the surface of the light emitting diode element 13. A part is placed by dripping or coating. Next, as shown in FIG. 3B, a liquid transparent resin constituting the diffusion portion 23 is disposed on the surface side of the light emitting diode element 13 by dropping, coating, or the like. At this time, the viscosity of the liquid transparent resin that constitutes the diffusing portion 23 is a viscosity that allows the position and shape of the dropped and applied liquid to be maintained to some extent, and is higher than the viscosity of the liquid transparent resin that constitutes the phosphor layer 24. It is in. Next, as shown in FIG. 3C, a liquid transparent resin constituting the phosphor layer 24 is disposed by dropping, coating, or the like so as to cover the entire inside of the recess 20. At this time, since the viscosity of the liquid transparent resin constituting the diffusion portion 23 is higher than the viscosity of the liquid transparent resin constituting the phosphor layer 24, the diffusion portion 23 and the phosphor layer 24 do not mix and diffuse. The position and shape of the part 23 can be maintained.

  Note that a lighting device can be configured by combining the light emitting device 11 and a lens.

  Next, the operation of the light emitting device 11 will be described.

  When a predetermined DC voltage is applied from the outside between the cathode-side and anode-side circuit patterns 16a and 16b, the light-emitting diode element 13 emits blue light, and blue light is emitted from the surface and side surfaces of the light-emitting diode element 13. . Blue light emitted from the surface of the light-emitting diode element 13 is incident on the diffusion part 23, diffuses in multiple directions at this diffusion part 23 and enters the phosphor layer 24, and the yellow phosphor of the phosphor layer 24 is multi-directional. Excited to emit yellow light. Blue light emitted from the side surface of the light-emitting diode element 13 enters the phosphor layer 24, and excites the yellow phosphor in the phosphor layer 24 to emit yellow light. Then, the blue light from the light emitting diode element 13 and the yellow light from the yellow phosphor are mixed and become white light, which is emitted from the inside of the recess 20 to the outside, that is, from the surface of the phosphor layer 24 to the outside.

  At this time, the diffusion portion 23 is provided at a position facing the light emitting diode element 13 in the concave portion 20 in the vertical direction and is substantially the same size as the light emitting diode element 13 when viewed in the vertical direction. The light of the light emitting diode element 13 traveling in the direction is diffused to reduce the light distribution in the vertical direction and increase the light distribution in the inclined direction with respect to the vertical direction.

  And the result of having measured the light distribution with the case where the spreading | diffusion part 23 is used and the case where it is not used is shown in FIG. FIG. 4A shows a light distribution diagram using the diffusing unit 23, and FIG. 4B shows a light distribution diagram of a comparative example that does not use the diffusing unit 23. In the figure, the direction perpendicular to the light emitting diode element 13 in the recess 20 is 0 °, the radial direction is the intensity of light intensity, blue light is indicated by a solid line, and yellow light is indicated by a broken line.

  In the case of the comparative example that does not use the diffusing portion 23 shown in FIG. 4B, there is a light distribution in which there is a large amount of blue light traveling in the vertical direction from the light emitting diode element 13 and a small amount of blue light traveling in the inclined direction with respect to the vertical direction. It has become. Moreover, the difference in luminous intensity between blue light and yellow light in the tilt direction is large. For this reason, when viewed from the vertical direction, color distortion tends to occur between the central portion and the peripheral portion, and the angle color difference depending on the viewing angle tends to increase.

  On the other hand, when the diffusing section 23 shown in FIG. 4 (a) is used, blue light traveling in the vertical direction from the light emitting diode element 13 is diffused, so that the blue light in the vertical direction is reduced and accompanying this. Yellow light is also reduced and vertical light distribution is reduced. On the other hand, since blue light traveling in the vertical direction from the light emitting diode element 13 is diffused, blue light traveling in the tilt direction with respect to the vertical direction increases, and yellow light increases accordingly, and light distribution in the tilt direction increases. . In addition, the difference in luminous intensity between blue light and yellow light in the tilt direction decreases.

  Therefore, light is emitted in the vertical direction by the diffusion portion 23 provided at a position facing the light emitting diode element 13 in the concave portion 20 in the vertical direction and having a size approximately equal to the size of the light emitting diode element 13 in the vertical direction. The light from the diode element 13 can be diffused to reduce the light distribution in the vertical direction, and the light distribution in the tilt direction with respect to the vertical direction can be increased, so that the color deviation and the angular color difference can be reliably improved.

  Further, after the diffusion part 23 is formed on the light emitting diode element 13 in the recess 20 with a resin material having a higher viscosity than the phosphor layer 24, the phosphor layer 24 is formed with a resin material having a lower viscosity than the resin material of the diffusion part 23. By forming in 20, the diffusion part 23 and the phosphor layer 24 can be easily formed in the recess 20.

  A part of the light diffused by the diffusing portion 23 is reflected from the bottom surface of the concave portion 20 toward the substrate 14 side. Therefore, by increasing the reflectance of the bottom surface of the concave portion 20, the direction toward the inclined direction with respect to the vertical direction is increased. Light distribution can be further increased and luminous efficiency can be improved. In order to increase the reflectance of the bottom surface of the recess 20, for example, a white resin is used for the insulating layer 15, and the light emitting diode element 13 is disposed on the insulating layer 15 with an adhesive or the like, and the circuit patterns 16a and 16b are arranged. It is possible to increase the surface area of the white insulating layer 15 on the bottom surface of the recess 20 by electrical connection by wire bonding.

  Further, the base 18 may be a metal frame integrally molded with resin.

1 is a partial cross-sectional view of a light-emitting device showing an embodiment of the present invention. It is a front view of a light-emitting device same as the above. It is explanatory drawing which shows the formation method of the spreading | diffusion part and fluorescent substance layer of a light-emitting device same as the above in order of (a) (b) (c). The light distribution of the light emitting device is shown. (A) is a light distribution diagram using a diffusion portion, and (b) is a light distribution diagram of a comparative example that does not use a diffusion portion.

Explanation of symbols

11 Light emitting device
13 Light-emitting diode elements as light-emitting elements
18 substrate
20 Recess
23 Diffusion part
24 phosphor layer

Claims (2)

A substrate having a recess;
A light emitting device disposed on the bottom side in the recess;
It is provided at a position facing the light emitting element in the concave portion in the vertical direction and approximately the same size as the light emitting element when viewed in the vertical direction, and diffuses light from the light emitting element toward the vertical direction to A diffuser that reduces the light distribution and increases the light distribution in the direction of inclination with respect to the vertical direction;
A phosphor layer having a phosphor that is formed in the recess so as to cover the light emitting element and the diffusion part and is excited by light of the light emitting element to emit light;
A light-emitting device comprising: The diffusion part and the phosphor layer formed in the recess are resin materials having a viscosity lower than that of the resin material of the diffusion part after the diffusion part is formed on the light emitting element in the recess with a resin material having a higher viscosity than the phosphor layer. The phosphor layer is formed in the recess, The light-emitting device according to claim 1.

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