JP2008294378A - Light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting device which can suppress decline in emission efficiency by temperature rise of a phosphor at the time of light-emitting and thermal degradation of color converting members. <P>SOLUTION: The light-emitting device includes two color converting members 30 and 40 arranged in concentricity focusing on an LED chip 10 at a mounting surface side of the LED chip 10 on a mounting board 20. Each of color converting members 30 and 40 is arranged so that the first regions 31 and 41 which contain a phosphor, and the second regions 32 and 42 which do not contain a phosphor may line alternately. The first regions 31 and 41 and the second regions 32 and 42 of each are arranged so that the first region 31 of the first color converting member 30 and the first region 41 of the second color converting member 40 may not overlap, and the second region 32 of the first color converting member 30 and the second region 42 of the second color converting member 40 may not overlap, seeing from the LED chip 10. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a light emitting device using an LED chip (light emitting diode chip).

  Conventionally, as a GaN-based LED chip that emits blue light or ultraviolet light and a color conversion material (wavelength conversion material) that emits light of an emission color different from the LED chip when excited by light emitted from the LED chip. Research and development of light emitting devices that emit light having a color different from the light emission color of the LED chip, including white, by combining with phosphors has been carried out in various places (for example, see Patent Document 1). Note that this type of light emitting device has advantages such as small size, light weight, and power saving. For example, a light source that is an alternative to a small light bulb (incandescent light bulb, halogen light bulb, etc.) Light).

  Here, in the above-mentioned Patent Document 1, a mounting substrate in which a housing recess for housing the LED chip is formed on one surface, an LED chip mounted on the inner bottom surface of the housing recess in the mounting substrate, and radiation from the LED chip. Color conversion member disposed on the one surface side of the mounting substrate, which is formed of a flat plate-like translucent member containing a phosphor that emits light of a color different from the emission color of the LED chip when excited by the emitted light There is proposed a light emitting device in which color conversion members are arranged so that first regions and second regions belonging to groups having different color conversion characteristics are alternately arranged. Here, in Patent Document 1, an example in which a phosphor is included in one of the first region and the second region and a phosphor is not included in the other, or the first region and the second region, Examples in which the types of phosphors contained in are different are described.

In addition, when using the light-emitting device which can obtain white light like the light-emitting device described in the said patent document 1 for an illumination light source etc., while increasing the number of light-emitting devices, the junction temperature of LED chip is the maximum junction. Generally, a desired brightness is obtained by increasing the input power to the light-emitting device while not exceeding the temperature.
JP 2006-179684 A

  By the way, in the light emitting device in which the LED chip and the phosphor are combined as described above, when the input power is increased, the radiant energy of the blue light or the ultraviolet light emitted from the LED chip is increased, and the Stokes in the phosphor is increased. Since the total amount of heat generated due to the energy loss due to the shift increases and the temperature of the color conversion member formed of the translucent resin containing the phosphor rises, the light emitted from the LED chip and the radiation emitted from the phosphor In some cases, the balance with the emitted light is lost and the chromaticity shifts, and the lifetime is shortened due to thermal deterioration of the color conversion member.

  On the other hand, the light emitting device described in Patent Document 1 has an advantage that it is possible to reduce the amount of heat generated by the color conversion member. It has been desired to further reduce the thermal deterioration of the conversion member.

  The present invention has been made in view of the above-described reasons, and an object thereof is to provide a light emitting device capable of suppressing a decrease in light emission efficiency due to a temperature rise of a phosphor during light emission and a thermal deterioration of a color conversion member. .

  The invention of claim 1 includes an LED chip, a mounting substrate on which the LED chip is mounted, and a phosphor that emits light of a color different from the emission color of the LED chip when excited by light emitted from the LED chip. Two color conversion members that are concentrically arranged around the LED chip on the mounting surface side of the LED chip on the mounting substrate, and each of the color conversion members includes a phosphor. The first region that is arranged so that the first region that is contained and the second region that does not contain the phosphor are alternately arranged, as viewed from the LED chip, is a color conversion member closer to the LED chip. The first area of the color conversion member and the first area of the second color conversion member that is the color conversion member on the far side do not overlap, and the second area of the first color conversion member and the second color conversion member In order not to overlap the second area Wherein the first region and the second region in the record is located.

  According to the present invention, the LED chip on the mounting substrate is formed of the dome-shaped translucent member containing the phosphor that is excited by the light emitted from the LED chip and emits light of a color different from the emission color of the LED chip. Two color conversion members arranged concentrically with the LED chip as the center on the mounting surface side, each color conversion member including a first region containing phosphor and a second region not containing phosphor Are arranged in an alternating manner, and when viewed from the LED chip, a first color conversion member that is a color conversion member closer to the LED chip and a color conversion member that is farther from the first region of the first color conversion member. The first region and the second color conversion member are not overlapped with each other, and the second region of the first color conversion member and the second region of the second color conversion member are not overlapped with each other. Since two areas are arranged, It can phosphor suppress deterioration and color shift of the light emission efficiency due to the temperature quenching due to the temperature increase of the time, and it becomes possible to suppress thermal deterioration of the color conversion member.

  According to a second aspect of the present invention, in the first aspect of the present invention, the first phosphor as the phosphor to be contained in the first region of the first color conversion member and the first of the second color conversion member. The emission peak wavelength is different from that of the second phosphor contained in the region, and the emission peak wavelength of the first phosphor is longer than the emission peak wavelength of the second phosphor.

  According to this invention, it is possible to improve color rendering properties and to suppress secondary absorption of light emitted from the second phosphor into the first phosphor.

  A third aspect of the invention is characterized in that, in the first or second aspect of the invention, each of the color conversion members is fixed to the mounting substrate in such a manner that an air layer is formed between them.

  According to the present invention, a part of the light emitted from the phosphor of the second color conversion member is totally reflected at the inner interface of the second color conversion member, and thus returns to the first color conversion member side. The light extraction efficiency to the outside can be increased.

  According to the first aspect of the present invention, there is an effect that it is possible to suppress a decrease in luminous efficiency due to a temperature rise of the phosphor during light emission and a thermal deterioration of the color conversion member.

(Embodiment 1)
As shown in FIGS. 1A and 1B, the light emitting device of the present embodiment is excited by light emitted from the LED chip 10, the mounting substrate 20 on which the LED chip 10 is mounted, and the LED chip 10. The color conversion is made of a dome-shaped translucent member containing a phosphor that emits light of a color different from the emission color of the LED chip 10 and is disposed so as to surround the LED chip 10 with the mounting substrate 20. Gel-like material made of a sealing material that is filled in a space surrounded by a member (hereinafter referred to as a first color conversion member) 30, the first color conversion member 30 and the mounting substrate 20 and seals the LED chip 10. And a dome-like translucent member containing a phosphor that emits light of a color different from the emission color of the LED chip 10 when excited by the light emitted from the LED chip 10. Outside the color conversion member 30 A dome-shaped color conversion member (hereinafter referred to as a second color conversion member) 40, and an air layer 60 is formed between the first color conversion member 30 and the second color conversion member 40. Yes.

  The mounting substrate 20 is formed by using an insulating substrate 21 made of a rectangular plate-shaped ceramic substrate (for example, a ceramic substrate having electrical insulation and high thermal conductivity such as an alumina substrate or an aluminum nitride substrate). The two wiring patterns 22 and 22 that are electrically connected to the respective electrodes of the LED chip 10 are formed. Here, each wiring pattern 22, 22 is formed across one surface (upper surface in FIG. 1 (b)), the side surface and the other surface (lower surface in FIG. 1 (b)) of the insulating substrate 21, Of each wiring pattern 22, 22, a portion formed across the side surface and the other surface constitutes external connection electrodes 22 b, 22 b. Each of the wiring patterns 22 and 22 includes a Cu film and an Au film on the Cu film. The insulating substrate 21 is not limited to a ceramic substrate, and an epoxy resin substrate, a hollow substrate, or the like may be used.

  Further, in the light emitting device of this embodiment, a rectangular heat radiating conductor portion 26 for radiating heat generated in the LED chip 10 is formed in the central portion of the other surface of the insulating substrate 21 in the mounting substrate 20. Therefore, when mounting on a wiring board (not shown), the heat dissipating conductor part 26 is fixed to the conductor pattern of the wiring board through a joint portion made of solder and thermally coupled to the wiring board, whereby the LED chip 10 Temperature rise can be suppressed. The heat radiating conductor 26 is formed of the same material as the wiring patterns 22 and 22. Further, the heat dissipating conductor portion 26 is set to have a larger planar size than the LED chip 10.

  On the other hand, the LED chip 10 is a GaN blue LED chip that emits blue light, and a light emitting portion made of a GaN compound semiconductor material is formed on one surface side of a base substrate made of a sapphire substrate that is a crystal growth substrate. Each electrode is electrically connected to the wiring patterns 22 and 22 of the mounting substrate 20 via bumps 16 and 16 made of a metal material (Au in this embodiment). In the present embodiment, a sapphire substrate is employed as the base substrate in the LED chip 10, but the base substrate is not limited to the sapphire substrate, and may be a SiC substrate or the like. Further, the base substrate is not limited to the crystal growth substrate, and may be a Si substrate or the like bonded to the light emitting portion after crystal growth (in this case, the crystal growth substrate is removed). In the present embodiment, the LED chip 10 is flip-mounted on the mounting substrate 20, but a mounting structure using bonding wires may be employed.

  Each of the color conversion members 30 and 40 is a particle-like material that is excited by absorbing blue light emitted from the LED chip 10 in a translucent material such as a silicone resin and emits yellow light having lower energy than the blue light. It is comprised by the translucent member containing yellow fluorescent substance. The translucent material used as the material of the color conversion members 30 and 40 is not limited to the silicone resin, and for example, an epoxy resin or glass may be employed.

  The color conversion members 30 and 40 described above are fixed to the mounting substrate 20 using an adhesive (for example, a silicone resin, an epoxy resin, or the like) over the entire periphery of the opening.

  Moreover, although the silicone resin is employ | adopted as a sealing material of the sealing part 50, you may employ | adopt not only a silicone resin but an epoxy resin, glass, etc., for example. The sealing unit 50 seals the LED chip 10 and the bumps 16 and 16 that are electrically connected to the electrodes of the LED chip 10.

  By the way, the above-mentioned two color conversion members 30 and 40 are disposed concentrically around the LED chip 10 on the mounting surface side of the LED chip 10 in the mounting substrate 20, and the first region containing the phosphor is included. 31 and 41 and the 2nd field 32 and 42 which do not contain fluorescent substance are arranged so that it may line up alternately. More specifically, each of the color conversion members 30 and 40 includes a group of first regions 31 and 41 that contain phosphors and a phosphor that does not contain phosphors. The area is divided into two areas 32 and 42. In the present embodiment, the first regions 31 and 41 contain a phosphor (yellow phosphor), while the second regions 32 and 42 do not contain a phosphor, and the first region 31 in plan view. , 41 and the second regions 32, 42 are arranged in a checkered pattern.

  Here, each of the color conversion members 30 and 40 is the first region 31 and the second region of the first color conversion member (that is, the color conversion member closer to the LED chip 10) 30 when viewed from the LED chip 10. The first region 41 of the color conversion member (that is, the color conversion member far from the LED chip 10) 40 does not overlap, and the second region 32 of the first color conversion member 30 and the second color conversion member The first regions 31 and 41 and the second regions 32 and 42 are arranged so as not to overlap the 40 second regions 42.

  Therefore, in the light emitting device of the present embodiment, the blue light emitted from the LED chip 10 and the yellow light emitted from the yellow phosphors of the color conversion members 30 and 40 are emitted to the outside through the light emission surface of the color conversion member 40. As a result, white light can be obtained.

  In the present embodiment, the chip size of the LED chip 10 is 1 mm □, the planar size of the mounting substrate 20 is 8 mm □, the thickness is 0.3 mm, the inner diameter of the first color conversion member 30 is 3.5 mm, and the outer diameter. Is 4.5 mm, the thickness is 0.5 mm, the inner diameter of the second color conversion member 40 is 5.5 mm, the outer diameter is 6.5 mm, and the thickness is 0.5 mm. There is no particular limitation. In the light emitting device of the present embodiment, a high output type GaN-based blue LED chip is used as the LED chip 10, so that the junction temperature of the LED chip 10 does not exceed the maximum junction temperature and a desired light output is obtained. As can be seen, the input power to the LED chip 10 is, for example, about 1 to 3 W.

  In the light emitting device of the present embodiment described above, a dome-shaped translucent member containing a phosphor that is excited by light emitted from the LED chip 10 and emits light of a color different from the emission color of the LED chip 10. And two color conversion members 30 and 40 arranged concentrically around the LED chip 10 on the mounting surface side of the LED chip 10 in the mounting substrate 20. Each color conversion member 30 and 40 contains a phosphor. The first regions 31 and 41 and the second regions 32 and 42 not containing a phosphor are alternately arranged, and the color closer to the LED chip 10 when viewed from the LED chip 10. The first region 31 of the first color conversion member 30 that is the conversion member and the first region 41 of the second color conversion member 40 that is the color conversion member on the far side do not overlap, and the first color conversion member 30. Second region 32 of Since the first regions 31 and 41 and the second regions 32 and 42 are arranged so as not to overlap the second region 42 of the second color conversion member 40, the temperature of the phosphor during light emission is increased. It is possible to suppress a decrease in light emission efficiency and color shift due to temperature quenching, and to suppress thermal deterioration of the color conversion members 30 and 40. Here, in the light emitting device of the present embodiment, the first regions 31 and 41 of the color conversion members 30 and 40 contain phosphors, and the second regions 32 and 42 do not contain phosphors. A part of the heat generated in the phosphors 31 and 41 can be efficiently radiated through the adjacent second regions 32 and 42, and a decrease in luminous efficiency and a color shift due to a temperature rise of the phosphor during light emission. It can be suppressed more. In the present embodiment, the first regions 31, 41 and the second regions 32, 42 are regularly arranged in a checkered pattern, but the first regions 31, 41 and the second regions 32, 42 are arranged. It is not always necessary to line up regularly.

  Further, in the light emitting device of this embodiment, the color conversion members 30 and 40 are fixed to the mounting substrate 20 in such a manner that an air layer 60 is formed between them, so that the fluorescence of the second color conversion member 40 is Since a part of the light emitted from the body is totally reflected at the inner interface of the second color conversion member 40, it can be prevented from returning to the first color conversion member 30 side, and the light extraction efficiency to the outside can be improved. Can be increased.

  In the present embodiment, the space surrounded by the mounting substrate 20 and the first color conversion member 30 is enriched by the sealing portion 50 that seals the LED chip 10, but the space is filled with an inert gas atmosphere. Alternatively, a vacuum atmosphere may be used, or an air layer may be formed between the sealing portion 50 that seals the LED chip 10 and the light incident surface of the first color conversion member 30. Moreover, if the shape of each color conversion member 30 and 40 is a dome shape, it will not specifically limit. In the present embodiment, the air layer 60 is provided between the first color conversion member 30 and the second color conversion member 40. However, the first color conversion member 30 and the second color conversion member 40 You may make it interpose a transparent material layer from a translucent material (for example, silicone resin, glass, etc.) in between.

(Embodiment 2)
The basic configuration of the light emitting device of the present embodiment is substantially the same as that of the first embodiment. As shown in FIGS. 2A and 2B, the first regions 31 and 41 and the color conversion members 30 and 40, respectively. The difference is that the second regions 32 and 42 are arranged concentrically around the optical axis of the LED chip 10. That is, in the second color conversion member 40, a circular second region 42 is formed at the top where the optical axis of the LED chip 10 passes, and a ring-shaped first region 41 is formed around the second region 42. Ring-shaped second regions 42 are formed outside the first region 41. Hereinafter, the ring-shaped first regions 41 and the ring-shaped second regions 42 are alternately formed in order. Similarly, in the first color conversion member 30, a circular first region 31 is formed at the top where the optical axis of the LED chip 10 passes, and a ring-shaped second region 42 is formed around the first region 31. The ring-shaped first regions 31 are formed around the second region 32, and the ring-shaped second regions 32 and the ring-shaped first regions 31 are alternately formed in this order. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.

  Thus, in the light emitting device of the present embodiment, as in the first embodiment, the phosphor that is excited by the light emitted from the LED chip 10 and emits light of a color different from the emission color of the LED chip 10 is contained. Two color conversion members 30, 40 made of a dome-shaped translucent member and arranged concentrically around the LED chip 10 on the mounting surface side of the LED chip 10 on the mounting substrate 20, each color conversion member 30, 40 is arranged so that the first regions 31 and 41 containing the phosphor and the second regions 32 and 42 not containing the phosphor are alternately arranged, and when viewed from the LED chip 10, the LED chip 10. The first region 31 of the first color conversion member 30 that is the color conversion member on the near side with respect to the first region 41 of the second color conversion member 40 that is the color conversion member on the far side does not overlap, First color conversion member The first regions 31 and 41 and the second regions 32 and 42 are arranged so that the second region 32 of 0 and the second region 42 of the second color conversion member 40 do not overlap with each other. Therefore, it is possible to suppress a decrease in light emission efficiency and a color shift due to temperature quenching due to a temperature increase of the phosphor, and to suppress thermal deterioration of the color conversion members 30 and 40.

  In the light emitting device according to the present embodiment, the color conversion members 30 and 40 are arranged such that the first regions 31 and 41 and the second regions 32 and 42 are arranged concentrically. Alignment between each other is facilitated, and assembly is facilitated.

  By the way, in each above-mentioned embodiment, although single kind of yellow fluorescent substance is adopted as fluorescent substance contained in the 1st fields 31 and 41 of color conversion members 30 and 40, it is not restricted to single kind of yellow fluorescent substance. For the purpose of improving color adjustment and color rendering, etc., a plurality of kinds of phosphors whose emission colors are all yellow and whose emission spectra are different may be combined.

  Further, a plurality of types of phosphors having different emission colors (that is, a plurality of types having different peak wavelengths) may be used as the phosphors to be contained in the first regions 31 and 41 of the color conversion members 30 and 40. For example, By including the red phosphor and the green phosphor in the regions 31 and 41, white light with high color rendering can be obtained. However, when the color conversion members 30 and 40 contain two types of phosphors having different emission colors, for example, as described above, the first regions 31 and 41 contain the red phosphor and the green phosphor. When each phosphor is a phosphor having secondary absorption, a part of the green light emitted from the green phosphor is secondarily absorbed by the red phosphor. For example, the first color conversion member The first phosphor 31 whose emission peak wavelength is on the long wavelength side is contained in the first region 31 of 30 (here, the red phosphor), and the emission peak wavelength is present in the first region 41 of the second color conversion member 40. It is desirable to reduce heat generation due to the secondary absorption by including a second phosphor (here, a green phosphor) on the short wavelength side.

  Further, when two or more kinds of phosphors having different peak wavelengths and no secondary absorption are contained in the color conversion members 30 and 40, for example, as described above, the first regions 31 and 41 have a red phosphor and a green phosphor. When the phosphor is included, the light emitted from the red phosphor is scattered by the green phosphor, and the light emitted from the green phosphor is scattered by the red phosphor. For example, for example, the first phosphor The first region 31 of the color conversion member 30 contains a red phosphor whose emission peak wavelength is on the long wavelength side, and the first region 41 of the second color conversion member 40 is green whose emission peak wavelength is on the short wavelength side. It is desirable to reduce heat generation due to the scattering by containing a phosphor.

The light-emitting device of Embodiment 1 is shown, (a) is a schematic plan view, (b) is a schematic sectional drawing. The light-emitting device of Embodiment 2 is shown, (a) is a schematic plan view, (b) is a schematic sectional drawing.

Explanation of symbols

10 LED chip 20 mounting substrate 30 color conversion member (first color conversion member)
31 1st area | region 32 2nd area | region 40 Color conversion member (2nd color conversion member)
41 1st area | region 42 2nd area | region 50 Sealing part 60 Air layer

Claims (3)

  A dome-shaped light transmission containing an LED chip, a mounting substrate on which the LED chip is mounted, and a phosphor that emits light of a color different from the emission color of the LED chip when excited by light emitted from the LED chip And two color conversion members concentrically arranged around the LED chip on the mounting surface side of the LED chip on the mounting substrate, each color conversion member including a first region containing a phosphor, The first region of the first color conversion member which is arranged so that the second regions not containing the phosphor are alternately arranged and is a color conversion member closer to the LED chip as viewed from the LED chip. The first region of the second color conversion member, which is the far side color conversion member, does not overlap, and the second region of the first color conversion member and the second region of the second color conversion member do not overlap. So that the first territory in each And a light-emitting device in which the second region is characterized in that it is arranged.   Emission peak wavelength of a first phosphor that is a phosphor contained in the first region of the first color conversion member and a second phosphor that is contained in the first region of the second color conversion member The light emitting device according to claim 1, wherein the emission peak wavelength of the first phosphor is longer than the emission peak wavelength of the second phosphor.   3. The light emitting device according to claim 1, wherein each of the color conversion members is fixed to the mounting substrate in such a manner that an air layer is formed between the color conversion members.

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