JP2009076494A - Light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device capable of improving optical output since the temperature rise of a color conversion part can be suppressed without allowing a heat dissipating member to cause adverse influence on optical characteristics, and capable of suppressing secondary absorption by phosphors while adopting two kinds of phosphors having different emission peak wavelengths as the phosphors of the color conversion part. <P>SOLUTION: A reflector 31 disposed in the thickness direction of a mounting substrate 2 by parting it from the mounting surface of an LED chip 1 in the mounting substrate 2 of an LED unit A to reflect light emitted from the LED chip 1 toward a light distribution lens 21, and the color conversion part 41 stuck to the inside face of the reflector 31 are provided in a translucent unit B, and the reflector 31 also serves as the heat dissipating member to dissipate heat generated in the color conversion part 41. A first color conversion region 41a containing a green phosphor (first phosphor) and a second color conversion region 41b containing a red phosphor (second phosphor) are alternately disposed so as not to be overlapped in the thickness direction in the color conversion part 41. <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 shown in FIG. 3, a plurality of LED chips 1 ′ and a storage recess 2a ′ for storing the plurality of LED chips 1 ′ are formed, and the plurality of LEDs are formed on the inner bottom surface of the storage recess 2a ′. A heat dissipating element 2 ′ made of a ceramic substrate on which the chip 1 ′ is mounted, and a heat sink formed of quartz glass and having a coolant flow path 9a ′ and closing the housing recess 2a ′ of the mounting substrate 2 ′. A translucent material (for example, translucent material) including a member 9 ′ and a phosphor that is excited by light emitted from each LED chip 1 ′ and emits light having a color different from the emission color of the LED chip 1 ′. There has been proposed a light emitting device including a color conversion portion 41 ′ formed of a resin and disposed on the light emitting surface side of the heat radiating member 9 ′ (see, for example, Patent Document 1).

Here, in the light emitting device described in Patent Document 1, for example, the emission color of the LED chip 1 ′ is blue, and the phosphor in the color conversion unit 41 ′ emits red light (red fluorescence). Body) and a phosphor that emits green light (green phosphor), so that one type of phosphor (yellow phosphor) that emits yellow light as the phosphor in the color conversion unit 41 ′. Compared to the case of using only, white light with high color rendering can be obtained.
JP-A-2005-294185 (paragraphs [0101]-[0103], [0056]-[0058], and FIG. 1)

  By the way, in the light emitting device having the configuration shown in FIG. 3, the heat generated in the color conversion unit 41 ′ can be radiated from the heat radiating member 9 ′. There is an advantage that a decrease in the conversion efficiency of the phosphor and the deterioration of the color conversion unit 41 ′ can be suppressed.

  However, since the above-described light emitting device requires the heat radiating member 9 ′ having the refrigerant flow path and the refrigerant, the entire device becomes large, and the heat radiating member 9 ′ forms the housing recess 2a ′ of the mounting substrate 2 ′. Since it arrange | positions in the form which obstruct | occludes, heat dissipation member 9 'will affect the optical characteristic of the said light-emitting device, and an optical output will fall. Further, in the above-described light emitting device, the color conversion portion 41 ′ is formed in a flat plate shape, so that there is a problem that uneven color is likely to occur.

  Further, in the above-described light emitting device, when two kinds of phosphors (red phosphor and green phosphor) having different emission peak wavelengths are employed as the phosphor of the color conversion unit 41 ′, the emission peak wavelength is on the low wavelength side. Since the light emitted from the phosphor (green phosphor) is secondarily absorbed by the phosphor (red phosphor) having the emission peak wavelength on the long wavelength side, there is a problem that the conversion efficiency is lowered. .

  The present invention has been made in view of the above-mentioned reasons, and the object thereof is to improve the light output by suppressing the temperature increase of the color conversion unit without adversely affecting the optical characteristics by the heat radiating member, and to improve the color output. An object of the present invention is to provide a light emitting device capable of suppressing the secondary absorption of the phosphor while adopting the first phosphor and the second phosphor having different emission peak wavelengths as the phosphor of the converter.

  The invention of claim 1 includes an LED unit in which an LED chip is mounted on one surface side of a mounting substrate, and a translucent unit disposed on the one surface side of the LED unit, and is mounted on the translucent unit. A reflector that is arranged away from the mounting surface of the LED chip on the substrate in the thickness direction of the mounting substrate and reflects light emitted from the LED chip to the light distribution lens side, and is attached to the inner surface of the reflector and emitted from the LED chip. And a color conversion part formed of a translucent material containing a phosphor that emits light of a color different from the emission color of the LED chip when excited by the reflected light, and the reflector is a phosphor of the color conversion part The LED unit also serves as a heat dissipating member that dissipates the generated heat, and the LED unit includes an optical member that distributes light emitted from the LED chip to the color conversion unit side, and changes the color of the translucent unit. A first color conversion region containing a first phosphor as the phosphor, and a second phosphor containing a second phosphor having an emission peak wavelength longer than the first phosphor as the phosphor. The two-color conversion regions are alternately arranged so as not to overlap in the thickness direction.

  According to this invention, the color conversion part is attached to the inner side surface of the reflector, and the reflector also serves as a heat radiating member that dissipates heat generated by the phosphor of the color conversion part. The heat can be efficiently radiated from the reflector, the temperature increase of the color conversion unit can be suppressed without adversely affecting the optical characteristics by the heat radiating member, the light output can be improved, and the color conversion unit is the first phosphor as the phosphor. A first color conversion region containing one phosphor and a second color conversion region containing a second phosphor having an emission peak wavelength longer than the first phosphor as the phosphor are in the thickness direction. Therefore, the light emitted from the first phosphor can be suppressed from being secondarily absorbed by the second phosphor.

  According to a second aspect of the invention, in the first aspect of the invention, the translucent material is glass.

  According to this invention, it is possible to suppress the deterioration of the color conversion portion compared to the case where the translucent material is a resin.

  In the first aspect of the present invention, the temperature increase of the color conversion unit can be suppressed without adversely affecting the optical characteristics by the heat radiating member, the light output can be improved, and the emission peak wavelength is different as the phosphor of the color conversion unit. There is an effect that the secondary absorption of the phosphor can be suppressed while having the kind of phosphor.

(Embodiment 1)
In the light emitting device of this embodiment, as shown in FIG. 1A, an LED unit 1 in which an LED chip 1 is mounted on one surface side of a mounting substrate 2 and the one surface side of the LED unit A are arranged. The light transmitting unit B includes a light transmitting unit B, and the light transmitting unit B transmits light emitted from the LED chip 1 which is disposed away from the mounting surface of the LED chip 1 on the mounting substrate 2 in the thickness direction of the mounting substrate 2. And the light emitting color of the LED chip 1 that is excited by the light emitted from the LED chip 1 that is attached to the inner surface of the reflector 31. Is provided with a color conversion unit 41 formed of a translucent material containing phosphors that emit light of different colors, and the reflector 31 dissipates heat generated by the phosphors of the color conversion unit 41. Also it serves. In addition, although the light distribution lens 21 which controls light distribution of the light radiated | emitted from LED chip 1 is provided in the translucent unit B, the light distribution lens 21 does not necessarily need to be provided.

  In the light emitting device of the present embodiment, a GaN-based blue LED chip that emits blue light is used as the LED chip 1, and the green phosphor is excited by the blue light emitted from the LED chip 1 as the phosphor of the color conversion unit 41. And a particulate phosphor that emits red light when excited by the blue light emitted from the LED chip 1 (a red phosphor). The blue light emitted from the LED chip 1 and transmitted through the color converter 41, the green light emitted from the green phosphor of the color converter 41, and the red light emitted from the red phosphor of the color converter 41 Is emitted from the light exit surface of the color conversion unit 41, and white light with high color rendering can be obtained. In the present embodiment, the green phosphor constitutes the first phosphor, and the red phosphor constitutes the second phosphor whose emission peak wavelength is on the longer wavelength side than the first phosphor. Yes.

  The LED unit A includes the LED chip 1 and the mounting substrate 2 described above, and a light-transmitting sealing material (for example, a silicone resin, an epoxy resin, or the like) that seals the LED chip 1 on the one surface side of the mounting substrate 2. A hemispherical sealing portion 3 and an optical member 5 that is provided on the light emitting surface side of the sealing portion 3 and distributes the light emitted from the LED chip 1 to the color conversion portion 41 side. The base member 4 made of a thermally conductive material (for example, a metal having high thermal conductivity such as Al or Cu) is joined and thermally coupled. The mounting substrate 2 is provided with a conductor pattern (not shown) for supplying power to the LED chip 1. Further, the mounting substrate 2 may be formed of a ceramic substrate provided with the conductor pattern, or a heat transfer plate on which the LED chip 1 is mounted, and the conductor pattern is provided so as to overlap the heat transfer plate. You may comprise with a wiring board. Here, in the latter case, a stress-reducing submount member that is formed of a heat conductive material (for example, AlN or alumina) and is interposed between the LED chip 1 and the heat transfer plate may be provided.

  The optical member 5 is provided with a columnar protruding portion 5b protruding continuously from the top of the dome-shaped main portion 5a surrounding the sealing portion 3 between the optical member 5 and a conical shape on the tip surface of the protruding portion 5b. The light emitted from the LED chip 1 to the side is transmitted through the sealing part 3 and the main part 5a, enters the color conversion part 41, and is emitted upward from the LED chip 1. The light is reflected by the boundary surface between the medium in the internal space of the recess 5 c and the medium of the optical member 5 and enters the color conversion unit 41. In addition, what is necessary is just to form the optical member 5 with translucent materials, such as a silicone resin and glass.

  LED unit A uses a resin sheet (for example, an organic green sheet such as an epoxy resin sheet highly filled with fused silica) containing a filler made of a filler such as silica or alumina and having a low viscosity when heated. The mounting substrate 2 and the base member 4 are joined by a resin sheet. Since the resin sheet has electrical insulation properties and high thermal conductivity, and has high fluidity during heating and high adhesion to the uneven surface, the resin sheet is interposed between the mounting substrate 2 and the base member 4. The generation of voids can be prevented, the increase in thermal resistance due to insufficient adhesion and the occurrence of variations can be prevented, and compared with the case where a rubber sheet-like heat radiating sheet is used, the LED chip 1 is connected to the base member. The thermal resistance up to 4 can be reduced, the heat dissipation is improved, the variation in thermal resistance is reduced, and the temperature rise of the junction temperature of the LED chip 1 can be suppressed, so that the input power can be increased and the light output is increased. Output can be achieved.

  On the other hand, the translucent unit B includes the light distribution lens 21, the reflector 31, and the color conversion unit 41 described above.

  The reflector 31 is designed so that the light emitted from the LED chip 1 and the light emitted from the color conversion unit 41 are reflected toward the light distribution lens 21, but the reflector 31 has a desired shape. Depending on the light distribution characteristics, it is only necessary to form a frame shape in which the opening area gradually increases as the distance from the LED chip 1 increases in the optical axis direction of the LED chip 1.

  As a material of the reflector 31, for example, a metal (for example, Al, Cu, etc.) having a high reflectance of light emitted from the phosphor of the LED chip 1 or the color conversion unit 41 and a higher thermal conductivity than the color conversion unit 41 is used. Etc.) may be employed, and Al is employed in the present embodiment. When Cu is used as the material of the reflector 31, it is desirable to metallize a reflective layer such as a Ni layer / Ag layer or a Ni layer / Al layer on the inner surface. The material of the reflector 31 is not limited to a metal, and a resin or ceramic having a higher thermal conductivity than that of the color conversion unit 41 may be used. For example, when a resin is used, a copper foil is used on the inner surface, for example. It is desirable to deposit and metallize a reflective layer such as a Ni layer / Ag layer or a Ni layer / Al layer on the copper foil.

  As the translucent material of the color conversion unit 41, a silicone resin is used. However, the resin is not limited to a silicone resin. For example, acrylic resin, glass, and organic and inorganic components are mixed and bonded at the nm level or molecular level. Organic / inorganic hybrid materials may be used.

  By the way, as shown in FIG.1 (b), the color conversion part 41 has the 1st color conversion area | region 41a containing the green fluorescent substance which is a 1st fluorescent substance as a fluorescent substance, and the 1st fluorescent substance as a fluorescent substance. Also, the second color conversion regions 41b containing the red phosphor that is the second phosphor having the emission peak wavelength on the long wavelength side are alternately arranged so as not to overlap in the thickness direction. Here, the color conversion units 41 are alternately arranged in the inner circumferential direction of the reflector 31.

  The light distribution lens 21 is a plano-convex lens in which the light incident surface is flat and the light output surface is formed in a convex curved surface, and is arranged so as to close the opening surface of the reflector 31 on the light extraction side. Here, the light distribution lens 21 is formed of a translucent material (for example, acrylic resin, glass, or the like). Note that the shape of the light distribution lens 21 is not limited to the shape of a plano-convex lens, and may be set as appropriate according to desired light distribution characteristics.

  By the way, in the light emitting device of the present embodiment, the cover member 20 formed of a translucent material and having the light distribution lens 21 is fixed to the base member 4, and the reflector block 30 having the reflector 31 inside the cover member 20. Is arranged. Here, the base member 4 is formed in a disc shape, and the cover member 20 is disposed apart from the base member 4 and has a front plate portion 20a in which a light distribution lens 21 is formed at a portion corresponding to the LED unit A. And the annular side plate portion 20b protruding continuously and integrally from the peripheral edge of the front plate portion 20a to the one surface side of the base member 4, and the reflector block 30 is disposed on the rear surface of the front plate portion 20a and is installed in the LED unit A. The flat plate part 30a in which the reflector 31 was formed in the site | part corresponding to this, and the annular | circular shaped side plate part 30b which protruded integrally from the peripheral edge of the flat plate part 30a to the said one surface side of the base member 4 are provided. Here, in the reflector block 30, the side plate portion 30b and the base member 4 are joined and thermally coupled using the resin sheet. The outer peripheral shape of the base member 4 is not particularly limited, and the outer peripheral shapes of the cover member 20 and the reflector block 30 may be appropriately set according to the outer peripheral shape of the base member 4. When the light distribution lens 21 is unnecessary, for example, the front plate portion 20a of the cover member 20 may be formed in a flat plate shape, and the front plate portion 20a constitutes a part of the translucent unit B, and the front plate The part corresponding to the LED unit A in the part 20a constitutes the light extraction part of the translucent unit B.

  In FIG. 1 (a), only one set of the LED unit A and the translucent unit B is shown, but a plurality of sets of the LED unit A and the translucent unit B are provided in an appropriate arrangement. In this case, a light distribution lens 21 is provided for each part corresponding to each LED unit A in the cover member 20, and a reflector 31 is provided for each part corresponding to each LED unit A in the reflector block 30, Further, a color conversion part 41 is provided for each reflector 31, and a circuit board in which a wiring pattern defining a connection relation of the plurality of LED units A is formed and a window hole into which each reflector 31 is inserted is formed as the base member 4. It is arranged in a space surrounded by the cover member 20, or the LED units A are connected by lead wires or the like according to the connection relationship. It may be. In the case where a plurality of sets of LED units A and translucent units B are appropriately arranged and applied to a lighting fixture, for example, the base member 4 is constituted by a fixture body, or the light emitting device is made of metal or the like. The base member 4 may be housed in an instrument body formed of a heat conductive material and thermally coupled to the instrument body by the resin sheet or the like.

  In the light emitting device of the present embodiment described above, the LED unit A in which the LED chip 1 is mounted on the one surface side of the mounting substrate 2, and the translucent unit B disposed on the one surface side of the LED unit A, The light transmitting unit B reflects light emitted from the LED chip 1 that is arranged away from the mounting surface of the LED chip 1 in the mounting substrate 2 in the thickness direction of the mounting substrate 2 to the light distribution lens 21 side. A reflector 31 and a color conversion unit 41 attached to the inner surface of the reflector 31 are provided. The color conversion unit 41 is thermally coupled to the reflector 31, and the reflector 31 is generated by the phosphor of the color conversion unit 41. Since it also serves as a heat dissipating member that dissipates heat, the heat generated in the color conversion section 41 can be efficiently dissipated from the reflector 31, and the optical characteristics are adversely affected by the heat dissipating member. The temperature increase of the color conversion unit 41 can be suppressed, the luminous efficiency of the phosphor can be improved, the light output can be improved by increasing the input power to the LED chip 1, and the temperature increase of the color conversion unit 41 can be suppressed. As a result, reliability is improved. Further, according to the light emitting device of the present embodiment, the color conversion unit 41 has the first color conversion region 41a containing the first phosphor as the phosphor and the emission peak wavelength as compared with the first phosphor as the phosphor. Since the second color conversion regions 41b containing the second phosphor on the long wavelength side are alternately arranged so as not to overlap in the thickness direction, the light emitted from the first phosphor is the second It is possible to suppress secondary absorption by the phosphor. In addition, when glass is used as the light-transmitting material of the color conversion unit 41, deterioration of the color conversion unit 41 can be suppressed as compared with the case where a resin such as a silicone resin is used.

(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 FIG. 1B, the first color conversion area 41a and the second color conversion area 41b of the color conversion unit 41 are planar. The difference is that the first color conversion area 41a and the second color conversion area 41b do not overlap in the thickness direction by being arranged concentrically in view. Here, in the color conversion unit 41, the first annular color conversion area 41a and the second annular color conversion area 41b are alternately arranged. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.

  In the light emitting device of the present embodiment, the reflector 31 also serves as a heat radiating member that radiates the heat generated by the phosphor of the color conversion unit 41, as in the first embodiment. Therefore, the heat radiating member does not adversely affect the optical characteristics. The temperature conversion of the color conversion unit 41 can be suppressed, the light output can be improved, and the first color conversion region 41a and the second color conversion region 41b of the color conversion unit 41 are arranged so as not to overlap in the thickness direction. Therefore, the secondary absorption of the phosphor can be suppressed while having two types of phosphors having different emission peak wavelengths as the phosphor.

  By the way, in each above-mentioned embodiment, although the blue LED chip which radiates | emits blue light is employ | adopted as LED chip 1, LED chip 1 is not restricted to what radiates | emits blue light, For example, from blue light to blue light The light emission color of the phosphor in the color conversion unit 41 is not particularly limited. In addition, the combination of the two types of phosphors in the color conversion unit 41 is not limited to the combination of the green phosphor and the red phosphor, and may be a similar color (for example, yellow) and different in conversion peak wavelength.

Embodiment 1 is shown, (a) is a principal part schematic sectional drawing, (b) is a principal part schematic plan view. Embodiment 2 is shown, (a) is a principal part schematic sectional drawing, (b) is a principal part schematic plan view. It is a schematic sectional drawing which shows a prior art example.

Explanation of symbols

A LED unit B Translucent unit 1 LED chip 2 Mounting substrate 3 Sealing part 5 Optical member 21 Light distribution lens 31 Reflector 41 Color conversion part 41a First color conversion area 41b Second color conversion area

Claims (2)

  An LED unit in which an LED chip is mounted on one surface side of the mounting substrate, and a translucent unit disposed on the one surface side of the LED unit, and the LED chip mounting surface of the mounting substrate on the translucent unit A reflector that is arranged apart from the mounting substrate in the thickness direction and reflects light emitted from the LED chip to the light distribution lens side, and is excited by the light emitted from the LED chip that is attached to the inner surface of the reflector. And a color conversion part formed of a translucent material containing a phosphor that emits light of a color different from the light emission color of the chip, and the reflector dissipates heat generated by the phosphor of the color conversion part The LED unit also includes an optical member that distributes light emitted from the LED chip to the color conversion unit, and the color conversion unit of the translucent unit includes the phosphor. A first color conversion region containing a first phosphor, and a second color conversion region containing a second phosphor having a light emission peak wavelength on the longer wavelength side than the first phosphor as the phosphor. The light emitting device is characterized by being alternately arranged so as not to overlap in the thickness direction.   The light-emitting device according to claim 1, wherein the translucent material is glass.

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