JP4683013B2 - Light emitting device - Google Patents

Description

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

  Conventionally, a GaN-based LED chip (light emitting diode element) that emits blue light or ultraviolet light and a wavelength conversion material that emits light of an emission color different from that of 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 (fluorescent pigments, fluorescent dyes, etc.) are being carried out in various places. 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).

  In recent years, with the increase in the output of white LEDs, which are a kind of this type of light-emitting device, research and development for expanding white LEDs into lighting applications has become active. For example, when a single white LED cannot be used to obtain a desired light output, a plurality of white LEDs are connected to a single wiring board (for example, a metal base board or LED unit mounted on a glass cloth / epoxy resin copper-clad laminate, etc.) and the power supplied to each white LED is increased so that the entire LED unit has a desired light output. Generally, it is ensured.

  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. The total amount of heat generated due to the energy loss due to the shift increases, the luminous efficiency of the phosphor due to temperature quenching decreases, and the balance between the light emitted from the LED chip and the light emitted from the phosphor is lost. There was a case where the degree was shifted.

  On the other hand, as shown in FIGS. 2 and 3, an LED chip 2 ′ and a housing recess 10a ′ for housing the LED chip 2 ′ are formed, and the LED chip 2 ′ is formed on the inner bottom surface of the housing recess 10a ′. A mounting substrate 10 ′ made of a mounted ceramic substrate, and a sealing portion 30 ′ that seals the LED chip 2 ′ housed in the housing recess 10a ′ of the mounting substrate 10 ′. The transparent resin layer 31 ′ formed of a transparent resin and covering the LED chip 2 ′, and the fluorescence that is excited by the light emitted from the LED chip 2 ′ and emits light of a color different from the emission color of the LED chip 2 ′ A color conversion layer 32 ′ formed of a transparent resin containing a body and laminated on the transparent resin layer 31 ′, and a heat radiating member 50 ′ thermally coupled to the mounting substrate 10 ′ is embedded in the color conversion layer 32 ′. A light-emitting device is proposed. (See Patent Document 1).

Here, in the light emitting device having the configuration shown in FIG. 2, a heat radiating wire made of a metal material is embedded in the color conversion layer 32 ′ as the heat radiating member 50 ′, and the light emitting device having the configuration shown in FIG. As the member 50 ′, a heat radiating mesh made of a metal material is embedded in the color conversion layer 32 ′.
Japanese Patent Laying-Open No. 2005-311170

  By the way, in the light emitting device having the configuration shown in FIGS. 2 and 3, a part of the heat generated in the color conversion layer 32 ′ is radiated to the mounting substrate 10 ′ through the heat radiating member 50 ′. However, since the end of the heat radiating member 50 ′ is only in contact with the mounting substrate 10 ′, the heat generated in the color conversion layer 32 ′ cannot be dissipated uniformly, and the color There was a problem that the temperature of the central portion was higher than that of the peripheral portion of the conversion layer 32 ′. Further, in the light emitting device having the configuration shown in FIGS. 2 and 3, a part of the light emitted from the LED chip 2 ′ and a part of the light emitted from the phosphor are blocked by the heat radiating member 50 ′. There was also a problem that the output decreased.

  The present invention has been made in view of the above-mentioned reasons, and an object thereof is to provide a light emitting device that can suppress a decrease in luminous efficiency and chromaticity deviation of a phosphor due to a temperature rise of the phosphor. It is in.

The invention according to claim 1, the flexible substrate, the off a light emitting diode element mounted on one surface side of the Rekishiburu substrate, et al provided the one surface on the smell of the full Rekishiburu substrate Te apart from the light - emitting diode element is a color conversion member sheet containing a phosphor which emits light of a different color from the emission color of the light - emitting diode element is excited by light emitted from the light - emitting diode element, of the full Rekishiburu substrate and a heat radiating member serving also as a support member for supporting the providing et Re the full Rekishiburu substrate to another surface, the full Rekishiburu substrate, forming a wiring pattern in which the light emitting diode element is electrically connected to said one surface In addition, the function of reflecting the light from the light emitting diode element and the light from the color conversion member and the heat generated by the color conversion member are released. Conductor pattern wherein the color converting member and a heat transfer function for transferring heat to the member side is fixed is made is formed in a central portion of said one surface, wherein the light emitted from the light - emitting diode element bent so as to obliquely incident on the surface of the color conversion member, a region overlapping each of the light emitting diode element and the color conversion member is characterized by comprising joined to the heat-member release said.

According to the present invention, the heat generated in the sheet-like color conversion member is efficiently radiated through the flexible substrate and the heat radiating member, so that the temperature increase and temperature variation in the color conversion member can be suppressed. Thus, it is possible to suppress a decrease in luminous efficiency and chromaticity shift caused by the phosphor temperature increase . Further, according to the present invention, the heat generated in the light emitting diode element is also efficiently dissipated through the flexible substrate and the heat radiating member, and the temperature rise of the junction temperature of the light emitting diode element can be suppressed. The output can be further 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 of the phosphor and a chromaticity shift caused by the temperature rise of the phosphor.

  As shown in FIG. 1, the light emitting device of the present embodiment includes a flexible substrate 1, a plurality of LED chips 2 mounted on one surface side of the flexible substrate 1, and each LED on the one surface side of the flexible substrate 1. A plurality of sealing portions 3 made of a sealing material (for example, silicone resin) that seals each of the chips 2 and the LED chip 2 that is provided on the one surface of the flexible substrate 1 so as to be radiated from the LED chips 2. On the other surface side of the flexible substrate 1 and a color conversion member 4 made of a sheet-like translucent member containing a phosphor that emits light of a color different from the emission color of the LED chip 2 when excited by the light emitted And a heat dissipating member 5 that also serves as a supporting member that supports the flexible substrate 1. In the present embodiment, the LED chip 2 constitutes a light emitting diode element.

  The LED chip 2 is a GaN-based blue LED chip that emits light in a blue wavelength range, and is mounted on the flexible substrate 1 and has a wiring pattern (not shown) formed on the one surface side of the flexible substrate 1. Electrically connected.

  The sealing portion 3 is formed in a hemispherical shape from a silicone resin, and has a function as a convex lens that enhances the directivity of light emitted from the LED chip 2 (that is, a convex lens that controls light distribution). .

  The color conversion member 4 is excited by absorbing blue light emitted from the LED chip 2 in a translucent material such as silicone resin, and emits yellow light having a lower energy than the blue light. An adhesive (e.g., silicone) is formed on a conductive pattern (not shown) formed on the central portion on the one surface side of the flexible substrate 1. Resin, epoxy resin, etc.). Here, the conductor pattern and the wiring pattern are formed of the same material and are formed at the same time. Moreover, the planar view shape of the said conductor pattern is the same rectangular shape as the color conversion member 4, and the said conductor pattern is a heat-transfer function which transfers the heat which generate | occur | produced in the color conversion member 4 to the heat radiating member 5 side, and LED. The blue light emitted from the chip 2 and transmitted through the color conversion member 4 and the yellow light emitted from the yellow phosphor of the color conversion member 4 to the flexible substrate 1 side are reflected to the surface side of the color conversion member 4. The plane size of the conductor pattern may be the same as or larger than that of the color conversion member 4. In the present embodiment, the thickness of the color conversion member 4 is set to 0.3 mm, but this thickness is not particularly limited.

  The flexible substrate 1 is bent so that light emitted from the LED chip 2 is incident on the surface of the color conversion member 4 from an oblique direction (specifically, in the projection region of the color conversion member 4 in the vertical direction). LED chip 2 does not exist and is bent so that the angle formed by the optical axis of LED chip 2 and the surface of color conversion member 4 is an acute angle), and the entire other surface is joined to heat dissipation member 5. . Here, the flexible substrate 1 has a copper plating film formed on the other surface side, and is joined by solder to the heat dissipation member 5 formed of a heat conductive material (Cu in this embodiment). . Here, in the flexible substrate 1, the wiring pattern is formed on one surface side of a base film (for example, polyimide film, polyester film, etc.) having electrical insulation and flexibility, and the copper plating film is formed on the other surface side. Has been. In addition, if the said heat conductive material is a material with high heat conductivity, it will not be restricted to Cu, For example, Al, Au etc. may be sufficient.

  The above-mentioned flexible substrate 1 has strip-shaped protruding pieces 1b extending from the center of each side edge of the rectangular main piece 1a, and the LED chip 2 is mounted on the tip of each protruding piece 1b. Yes. Here, the flexible substrate 1 is bent at the boundary between the main piece 1a and each protruding piece 1b, and the distance from the surface of the main piece 1a increases with distance from the boundary. Here, if the angle between the optical axis of the LED chip 2 and the surface of the color conversion member 4 is θ1, and the angle between the main piece 1a and the protruding piece 1b is θ2, θ2 = 90 ° −θ1. Yes.

  Further, the heat dissipation member 5 holds the rectangular plate-like base portion 5a to which the main piece 1a of the flexible substrate 1 is joined, and the protruding pieces 1b of the flexible substrate 1 from the central portions of the side edges of the base portion 5a. Thus, four strip-shaped arm portions 5b that are erected so that the protruding pieces 1b are joined to each other are formed continuously and integrally.

  In the light emitting device of the present embodiment described above, the blue light emitted from the LED chip 2 and the yellow light emitted from the yellow phosphor are emitted through the surface of the color conversion member 4 to obtain white light. The flexible substrate 1 is bent so that the light emitted from the LED chip 2 is incident on the surface of the color conversion member 4 from an oblique direction, and is joined to the heat radiating member 5. Since the heat generated in the conversion member 4 is efficiently radiated through the flexible substrate 1 and the heat radiating member 5, the temperature increase of the color conversion member 4 and the in-plane variation in temperature can be suppressed, and the temperature of the phosphor increases. It is possible to suppress a decrease in luminous efficiency and chromaticity shift caused by the phosphor. Further, in the light emitting device of this embodiment, the arm portion 5b of the heat radiating member 5 does not exist in the vertical projection region of the color conversion member 4, and is radiated from the LED chip 2 and transmitted through the color conversion member 4 to be flexible. The planar size of the color conversion member 4 and each of the above-mentioned values are set so that the light reflected by the conductor pattern of the substrate 1 does not enter the opposite LED chip 2 and the protruding piece 1b on which the opposite LED chip 2 is mounted. Since the angles θ1 and θ2 and the curvature of the surface of the sealing portion 3 are set, a part of the light emitted from the LED chip 2 and a part of the light emitted from the phosphor are blocked by the heat radiating member 5. Therefore, it is possible to prevent the light output from decreasing.

  By the way, in order to suppress the temperature rise of the color conversion member 4, at least a region overlapping with the color conversion member 4 may be joined to the heat dissipation member 5 in the flexible substrate 1. 1 is joined to the heat dissipation member 5, the heat generated in the LED chip 2 is also efficiently dissipated through the flexible substrate 1 and the heat dissipation member 5, and the temperature rise of the junction temperature of the LED chip 2 can be suppressed. The input power can be increased, and the optical output can be further increased.

  In the above-described embodiment, a blue LED chip that emits blue light is used as the LED chip 2. However, the LED chip 2 is not limited to one that emits blue light, for example, one that emits ultraviolet light. But you can. In the above-described embodiment, the LED chip 2 constitutes a light-emitting diode element. However, the light-emitting diode element is not limited to the LED chip, but, for example, an SMD type in which the LED chip is housed in a surface-mounted package with a lens. An LED may be used, and in this case, it is not necessary to separately provide the above-described hemispherical sealing portion 3.

  Moreover, the translucent material used as the material of the color conversion member 4 is not limited to the silicone resin, and for example, an epoxy resin, glass, or the like may be employed. Further, the phosphor to be contained in the translucent material used as the material of the color conversion member 4 is not limited to the yellow phosphor, and a plurality of types of phosphors may be used for the purpose of improving color adjustment and color rendering. White light with high color rendering properties can be obtained by using a red phosphor and a green phosphor. Here, when a plurality of types of phosphors are used, the phosphor is not necessarily a combination of phosphors having different emission colors, and for example, a plurality of types of phosphors having an emission color of yellow and different emission spectra may be combined.

The light-emitting device of embodiment is shown, (a) is a schematic perspective view, (b) is principal part schematic sectional drawing. It is a schematic sectional drawing of the light-emitting device which shows a prior art example. It is a schematic sectional drawing of the light-emitting device which shows another prior art example.

Explanation of symbols

1 Flexible substrate 2 LED chip (light emitting diode element)
3 Sealing part 4 Color conversion member 5 Heat dissipation member

Claims (1)

A flexible substrate, a light emitting diode element mounted on one surface side of the full Rekishiburu substrate, the full Rekishiburu Re said al one surface on odor Te installed apart from the light - emitting diode element of the substrate from the light - emitting diode element a color conversion member sheet containing a phosphor which emits light of a different color than the being excited by light emission color of the light - emitting diode emitted, Re et provided on the other surface side of the full Rekishiburu substrate and a heat radiating member serving also as a supporting member for supporting the full Rekishiburu substrate, the full Rekishiburu substrate, together with the wiring pattern the light-emitting diode elements are electrically connected is formed on the one surface side, the light emitting diode Reflecting the light from the element and the light from the color conversion member and transferring the heat generated by the color conversion member to the heat radiating member side Conductor pattern wherein the color converting member and a heat transfer function is fixed is made is formed in a central portion of said one surface, the light emitted from the light - emitting diode element surface of the color conversion member bent so as to obliquely incident, the light emitting device area overlapping to each of the light emitting diode element and the color conversion member is characterized by comprising joined to the heat-member release said.

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