CN100505348C - light emitting device - Google Patents

Abstract

The invention provides a light emitting device, wherein the light obtaining efficiency of light emitting device is not easy to loss even using resin base plate of good thermal conductivity. The light The invention provides a light emitting device, wherein the light obtaining efficiency of light emitting device is not easy to loss even using resin base plate of good thermal conductivity. The light emitting device comprises a resin base plate 14 with thermal conductivity of 1. 0~9.0W/m.K; white insulating layer 15 on the resin base plate; circuit charting layer 16 above the insulating layer; luemitting device comprises a resin base plate 14 with thermal conductivity of 1. 0~9.0W/m.K; white insulating layer 15 on the resin base plate; circuit charting layer 16 above the insulating layer; luminoous element 13 above the insulating layer and conductively connecting with circuit charting layer. minoous element 13 above the insulating layer and conductively connecting with circuit charting layer.

Description

light emitting device

technical field

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

Background technique

Conventionally, as an example of a light emitting diode device, a surface mount type light emitting diode device is known in which a case (groove) in which a light emitting diode chip is placed is filled with synthetic resin and the light emitting diode chip is sealed in the case (see Patent Document 1).

In addition, in such a light-emitting diode device, a case is known in which a synthetic resin such as PPA (polyphthalamide) is used, but the thermal conductivity of this synthetic resin is, for example, about 0.3 W/m·K, and the heat dissipation is low. , so there is a problem that the luminous efficiency of the light emitting diode chip decreases as the temperature rises.

In addition, in the known light-emitting diode device of the second prior art, in order to suppress its temperature rise, a heat dissipation hole is drilled on the ceramic substrate, and an auxiliary ceramic sheet is provided on the inner surface side of the heat dissipation hole, and on the auxiliary ceramic sheet By mounting the light emitting diode chip, the heat dissipation of the light emitting diode chip can be improved (see Patent Document 2).

Patent Document 1: Japanese Patent Laid-Open No. 2002-43625

Patent Document 2: Japanese Patent Laid-Open No. 2002-353515

Contents of the invention

When a resin with good heat dissipation is used, the heat of the LED element can be efficiently dissipated to prevent the decrease of the luminous efficiency of the LED element, but this resin is not white, so the light reflectance is low, and it is emitted from the LED element to the substrate The light of the light-emitting diode element is easily absorbed, so there is a problem that the efficiency of capturing the light of the light-emitting diode element is low.

An object of the present invention is to provide a light-emitting device in which the light-acquisition efficiency of a light-emitting element is less likely to be lowered even if a resin substrate having good thermal conductivity is used.

The first aspect of the present invention is characterized by comprising a resin substrate having a thermal conductivity of 1.0 to 9.0 W/m·K, a white insulating layer provided on the resin substrate, a circuit pattern layer provided on the insulating layer, A light-emitting element arranged on an insulating layer and electrically connected to a circuit layout layer.

The resin constituting the resin substrate is made to have a thermal conductivity of 1.0 to 9.0 W/m·K by adding 50 to 90% by mass of inorganic filler to a synthetic resin base material such as polyamide or PPA (polyphthalamide). From this resin substrate, a concave portion for arranging a light emitting element can be formed. In addition, since the resin substrate has electrical insulation properties, it is not necessary to form an electrical insulating layer between the circuit layout layer, but in the present invention, a white electrical insulating layer is provided in order to improve reflectivity.

In addition, this resin is a high heat dissipation synthetic resin with a thermal conductivity of 1.0 to 9.0 W/m·K, so heat dissipation can be improved. Therefore, it is possible to suppress a decrease in luminous efficiency of the light-emitting element due to an increase in temperature. In addition, the thermal conductivity of the resin substrate may be 9.0 W/m·K or more. In this case, since the content of the inorganic filler contained in the synthetic resin base material increases, the fluidity of the synthetic resin base material decreases and the processability decreases, but the heat dissipation can be further improved. In addition, a white resin material may be used for the white insulating layer.

The second aspect of the present invention is characterized by comprising a resin substrate having a thermal conductivity of 1.0 to 9.0 W/m·K, a white insulating layer provided on the resin substrate, a circuit pattern layer provided on the insulating layer, The reflector provided on the insulating layer of the substrate and the circuit layout layer, the light-emitting element provided on the insulating layer in the central area of the storage part of the reflector and electrically connected with the circuit layout layer located in the peripheral area of the storage part, so The reflector has a structure in which openings are provided on the insulating layer and the circuit layout layer of the substrate corresponding to the arrangement positions of the light-emitting elements, and the circuit layout layer is located in the peripheral region of the storage part.

A third aspect of the present invention is the light-emitting device according to the second aspect, wherein the ratio of the surface area of the insulating layer facing the inside of the housing portion is larger than the ratio of the surface area of the circuit pattern layer.

Claim 4 of the present invention is the light-emitting device according to any one of Claims 1 to 3, wherein the reflectance on the surface of the insulating layer is 85% or more in the wavelength range of 400 to 740 nm. If the reflectance of the surface of the insulating layer is less than 85% in the wavelength region of 400 to 740 nm, the efficiency of reflecting light emitted from the light-emitting element to the substrate side by the insulating layer is low, and the light acquisition efficiency of the light-emitting element cannot be sufficiently improved.

Claim 5 of the present invention is the light-emitting device according to any one of Claims 1 to 4, wherein the synthetic resin base material of the resin substrate contains 50 to 90% by mass of an inorganic filler.

The inorganic filler is at least one of alumina, magnesia, beryllium oxide, silicon oxide, boron nitride, aluminum carbide, silicon carbide, boron carbide, titanium carbide, silicon nitride, diamond, iron, aluminum, copper, or one of them Combination of 2 or more types. By adjusting the content of the inorganic filler, the heat dissipation of the resin substrate can be easily adjusted to an appropriate value.

A sixth aspect of the present invention is the light-emitting device according to the fifth aspect, wherein the inorganic filler has an approximately spherical shape with a diameter of 100 μm or less. Since the inorganic filler has a spherical shape with a diameter of 100 μm, it is possible to improve the injection molding efficiency of the high heat dissipation synthetic resin and realize dense filling.

If the light-emitting device described in item 1 of the present invention is adopted, a white insulating layer is set on a resin substrate with good heat dissipation, a circuit layout layer is arranged, a light-emitting element is arranged on the insulating layer, and the light-emitting element and the circuit layout layer are connected to each other. Therefore, not only the heat dissipation is good, but also the light emitted from the light-emitting element to the substrate side can be efficiently reflected by the white insulating layer, and the light acquisition efficiency of the light-emitting element can be improved.

If the light-emitting device described in the second item of the present invention is adopted, a white insulating layer is provided on a resin substrate with good heat dissipation, and a circuit layout layer is provided, and the storage of the reflector provided on these insulating layers and the circuit layout In the central area of the interior, light-emitting elements are arranged on the insulating layer, and at the same time, it is electrically connected to the circuit layout layer in the peripheral area in the housing area through wire bonding, so not only heat dissipation is good, but also self-luminescence can be reflected efficiently through the white insulating layer The light emitted from the element to the substrate side can improve the light acquisition efficiency of the light emitting element.

If the light-emitting device described in claim 3 of the present invention is adopted, in addition to the effect of the light-emitting device in claim 2 of the present invention, it also has the ratio of the surface area ratio of the insulating layer facing the housing portion to the surface area ratio of the circuit layout layer. Therefore, the light emitted from the light-emitting element to the substrate side can be efficiently reflected by the white insulating layer, and the light acquisition efficiency of the light-emitting element can be improved.

If the light-emitting device described in item 4 of the present invention is adopted, in addition to the effect of any one of the light-emitting device in items 1 to 3 of the present invention, it is also due to the reflectivity of the surface of the insulating layer in the 400-740 nm wavelength region. If it is more than 85%, the white insulating layer can efficiently reflect the light emitted from the light-emitting element to the substrate side, and the light acquisition efficiency of the light-emitting element can be improved.

According to the light-emitting device according to the fifth aspect of the present invention, the content of the inorganic filler contained in the synthetic resin base material of the resin substrate is 50% by mass, and the synthetic resin with good processability is 50% by mass. It is easy to process and can improve heat dissipation. In addition, since the content of the inorganic filler is 90% or less, not only the heat dissipation can be further improved, but also the processability can be maintained because the content of the synthetic resin having good processability is 10% by mass.

According to the light-emitting device according to the sixth aspect of the present invention, since the inorganic filler is spherical with a diameter of 100 μm or less, the injection moldability of the highly heat-dissipating synthetic resin during injection molding can be improved, and the molding mold can be densely filled.

Description of drawings

FIG. 1 is a partially enlarged cross-sectional view showing a light emitting device according to an embodiment of the present invention.

Fig. 2 is a partially omitted enlarged front view of the light emitting device.

Fig. 3 is a front view of the above light emitting device.

FIG. 4 is an enlarged cross-sectional view of the above light emitting device.

Explanation of symbols

11...light emitting device, 13...light emitting diode element as a light emitting element, 14...resin substrate, 15...insulating layer, 16...circuit layout layer, 17...reflector, 19...accommodating portion.

Detailed ways

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 is a partially enlarged cross-sectional view of the light emitting device, FIG. 2 is a partially omitted enlarged front view of the light emitting device, FIG. 3 is a front view of the light emitting device, and FIG. 4 is an enlarged cross-sectional view of the light emitting device.

In the figure, the light-emitting device 11 includes a light-emitting module 12 that is detachably attached to a light-emitting device main body (not shown), such as a lighting fixture main body, for example. In the light emitting module 12 , a plurality of chip-shaped solid light emitting elements serving as light emitting elements, that is, light emitting diode elements (light emitting diode chips) 13 are arranged in a matrix. The light emitting diode element 13 is made of, for example, a gallium nitride (GaN)-based semiconductor or the like that emits blue light with a luminescence peak of 450 to 460 nm.

The light-emitting module 12 has, for example, a resin substrate 14 that contains 50 to 90% by mass of an inorganic filler in a synthetic resin substrate such as polyamide or PPA (polyphthalamide), and has a thermal conductivity of 1.0 to 9.0 W/m·K. , a white insulating layer 15 formed on one side of the substrate 14 , a circuit pattern layer 16 formed on the insulating layer 15 , and a reflector 17 integrally formed on the insulating layer 15 and the circuit pattern layer 16 .

The insulating layer 15 is formed of an insulating white resin material and completely covers one surface of the substrate 14 . The reflectance of the surface of the insulating layer 15 in the wavelength range of 400 to 740 nm is preferably more than 85%. If it is less than 85%, the efficiency of reflecting light from the light-emitting diode element 13 to the substrate 14 side in the insulating layer 15 is low, and cannot be achieved. A sufficient increase in the light extraction efficiency of the light emitting diode element 13 is obtained.

In the circuit layout layer 16, at the arrangement position of each light emitting diode element 13 as the arrangement position of the light emitting element, the circuit layout (wiring layout) on the cathode side and the anode side is formed by an alloy of Cu and Ni or Au, Ag, or the like. ) 16a, 16b.

The reflector 17 is integrally formed by pouring a resin such as PBT (polybutylene terephthalate) or PPA (polyphthalamide), PC (polycarbonate) into one side of the substrate 14, and is formed on each light emitting diode. A plurality of housing portions 19 for housing the light emitting diode elements 13 are formed at the arrangement positions of the elements 13 . Each housing portion 19 is formed in a truncated cone shape gradually expanding toward the opposite side with respect to the base plate 14 . A lens fixing part 20 for fixing a not-shown lens is concentrically formed around the storage part 19 .

At the bottom of each storage portion 19, the white insulating layer 15 is located in most of the central area including the bottom of the storage portion 19 and faces the storage portion 19, and the circuit layouts 16a, 16b have a minimum size required for wire bonding. The end portion is located in the peripheral area of the bottom of the receiving portion 19 . That is, the ratio of the surface area of the insulating layer 15 facing the interior of the housing portion 19 is larger than the ratio of the surface area of the circuit layout layer 16 .

Each LED element 13 is disposed on the insulating layer 15 using an adhesive or the like in the central area of the housing portion 19, and each electrode of the LED element 13 is electrically connected to each circuit layout 16a, 16b through the bonding wire 21 using wire bonding.

A coating layer 22 that covers the light emitting diode element 13 is formed in each housing portion 19 . The covering layer 22 is formed of two layers: a diffusion layer 23 covering the light emitting diode element 13 and a phosphor layer 24 arranged on the opening side of the housing portion 19 on the upper layer of the diffusion layer 23 .

The diffusion layer 23 is made by doping aluminum oxide (Al ₂ O ₃ ) or TiO ₂ , BaSO ₄ , SiO ₂ , SiO ₂ , Y ₂ O into thermosetting transparent resin such as light-transmitting silicone resin or epoxy resin. The layer formed of a diffusing agent such as ₃ is formed by filling the resin doped with the diffusing agent at a position higher than the light emitting diode element 13 in the housing portion 19 and thermally curing it. The bonding surface (interface) 25 between the diffusion layer 23 and the phosphor layer 24 is formed as a curved surface concave toward the light emitting diode element 13 side (the lower side in FIG. 1 ).

The phosphor layer 24 is a layer in which a yellow phosphor that receives blue light from the light-emitting diode element 13 and emits yellow fluorescence is mainly mixed with a thermosetting transparent resin such as a light-transmitting silicone resin or an epoxy resin. , is formed by filling and curing a phosphor-doped resin into the housing portion 19 after the diffusion layer 23 is thermally cured. As the phosphor, a yellow phosphor is mainly used, and a red phosphor or the like may be mixed. In addition, a lighting device can be constituted by combining the light emitting device 11 and a lens.

Hereinafter, 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 layouts 16a, 16b, each light emitting diode element 13 emits blue light. The blue light diffuses in multiple directions through the diffusion layer 23 and enters the phosphor layer 24 , where the yellow phosphor is excited from multiple directions to emit yellow light. Next, the blue light from the light emitting diode element 13 and the yellow light from the yellow phosphor are mixed to form white light, which is emitted from the housing portion 19 to the outside.

Therefore, in this light-emitting device 11, the fine light emission of the light-emitting diode element 13 is diffused in multiple directions by the diffusion layer 23, and the yellow phosphor of the phosphor layer 24 is excited from multiple directions to emit yellow light. Yellow light and blue light are mixed to make it emit white light, so white light can be reduced into yellow light and blue light.

In addition, since this resin has high heat dissipation with a thermal conductivity of 1.0 to 9.0 W/m·K, it is possible to conduct heat from the light emitting diode element 13 to the resin substrate 14 to improve heat dissipation. Therefore, it is possible to suppress a decrease in the luminous efficiency of the light emitting diode element 13 due to a rise in temperature.

In addition, the light emitted from the light-emitting diode element 13 toward the substrate 14 can be efficiently reflected by the white insulating layer 15 , so that the light acquisition efficiency of the light-emitting diode element 13 can be improved.

In particular, since the surface area ratio of the insulating layer 15 facing the inside of the housing portion 19 is larger than the surface area ratio of the circuit pattern layer 16, and the reflectance of the surface of the insulating layer 15 is 85% or more in the wavelength range of 400 to 740 nm, it is possible to The white insulating layer 15 efficiently reflects the light emitted from the light emitting diode element 13 toward the substrate 14 side, thereby further improving the light acquisition efficiency of the light emitting diode element 13 .

Claims (5)

1. A light-emitting device, characterized in that it comprises a resin substrate having a thermal conductivity of 1.0 to 9.0 W/m·K, a white insulating layer disposed on the resin substrate, a circuit layout layer disposed on the insulating layer, a device For the light-emitting element on the insulating layer and electrically connected with the circuit layout layer, the reflectance of the surface of the insulating layer is above 85% in the wavelength region of 400-740nm. 2. A light-emitting device, characterized in that it comprises a resin substrate having a thermal conductivity of 1.0 to 9.0 W/m·K, a white insulating layer disposed on the resin substrate, a circuit layout layer disposed on the insulating layer, a device The reflector on the insulating layer and the circuit layout layer, the light-emitting element provided on the insulating layer in the central area of the storage part of the reflector and electrically connected to the circuit layout layer located in the peripheral area of the storage part, the reflector It has a structure in which an opening is provided on the insulating layer and the circuit layout layer corresponding to the arrangement position of the light-emitting element, and the circuit layout layer is located in the peripheral region of the storage part. Above 85%. 3. The light-emitting device according to claim 2, wherein a surface area ratio of the insulating layer facing the inside of the housing portion is larger than a surface area ratio of the circuit layout layer. 4. The light-emitting device according to any one of claims 1 to 3, wherein the synthetic resin base material of the resin substrate contains 50 to 90% by mass of an inorganic filler. 5. The light-emitting device according to claim 4, wherein the inorganic filler is approximately spherical with a diameter of 100 μm or less.

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