CN105990509A - High thermal conductivity light emitting diode - Google Patents

Abstract

A high thermal conductivity light emitting diode comprises a thermal conductive substrate, a light emitting unit arranged on the base surface of the plate body of the thermal conductive substrate, and an electrode unit electrically connected with the light emitting unit and used for providing electric energy to enable the light emitting unit to emit light. The heat-conducting substrate comprises a plate body and a plurality of heat-conducting fibers dispersed in the plate body. The plate body is provided with a base surface and a bottom surface opposite to the base surface. At least a portion of the thermally conductive fibers are exposed outside the plate body. The heat energy generated when the light-emitting unit emits light is conducted away from the light-emitting unit through the heat-conducting fibers of the heat-conducting substrate, so that the light-emitting efficiency is improved.

Description

High Thermal Conductivity Light Emitting Diodes

technical field

The invention relates to a light-emitting diode, in particular to a light-emitting diode with high thermal conductivity.

Background technique

Referring to FIG. 1 , the existing light-emitting diode 1 , taking a horizontal light-emitting diode as an example, mainly includes a sapphire substrate 11 , a light-emitting unit 12 disposed on the sapphire substrate 11 , and two electrode units 13 .

The light-emitting unit 12 includes an n-type gallium nitride (n-GaN) layer 121 formed on the surface of the sapphire substrate 11, a multi-quantum layer covering a surface of the n-type gallium nitride (n-GaN) layer 121. layer (MQW) 122, and a p-type gallium nitride (p-GaN) layer covering the surface of the multiple quantum layer (MQW) 122 . The electrode unit 13 includes a top electrode with the p-type gallium nitride (p-GaN) layer, and a bottom electrode with the n-type gallium nitride layer. When a current is passed through the electrode unit 13, the holes in the p-type gallium nitride (p-GaN) layer 123 and the electrons in the n-type gallium nitride (n-GaN) layer 121 are driven to The multiple quantum layers (MQW) 122 combine to emit light. However, since the light-emitting unit 12 generates a huge amount of heat when it emits light, and the sapphire substrate 11 has a low thermal conductivity (about 40W/m·K), the heat dissipation effect is poor, and the light-emitting diode is reduced. The luminous efficiency of body 1 as a whole.

In order to solve the heat dissipation problem of the sapphire substrate, such as the invention patent case of US8809898B2 Approval Announcement, a manufacturing method of a vertical light-emitting diode is disclosed, which mainly uses the substrate transfer method to convert the sapphire substrate into a good heat dissipation Metal substrate to improve heat dissipation efficiency. However, using the substrate transfer process makes the manufacturing process more complicated, and the sapphire substrate must be removed by laser lift-off, which also increases the manufacturing cost, and the replaced metal substrate will also add extra weight.

From the above description, it can be seen that how to solve the problem of heat dissipation of the light-emitting diode to improve the luminous efficiency, and at the same time avoid using the metal substrate to reduce the weight and manufacturing cost is a difficult problem for those skilled in the art to break through.

Contents of the invention

The object of the present invention is to provide a light-emitting diode with high thermal conductivity.

The high thermal conductivity light-emitting diode of the present invention includes a heat-conductive substrate, a light-emitting unit, and an electrode unit. The heat conduction substrate includes a board body and several heat conduction fibers dispersed on the board body. The board body has a base surface and a bottom surface opposite to the base surface. At least a part of the heat conducting fiber is exposed outside the board body. The light emitting unit is arranged on the base surface of the board body. The electrode unit is electrically connected with the light-emitting unit for providing electric energy to make the light-emitting unit emit light.

Preferably, in the aforementioned high thermal conductivity light-emitting diode, the thermal conductive fibers are arranged in a staggered weaving manner and have a porous structure.

Preferably, in the aforementioned high thermal conductivity light-emitting diode, the thermal conductive fibers are exposed from the base surface.

Preferably, in the aforementioned high thermal conductivity light-emitting diode, the thermal conductive fiber is exposed from the bottom surface and directly contacts with the outside.

Preferably, the above-mentioned high thermal conductivity light-emitting diode, wherein the board body further has several support blocks spaced apart from each other, the thermal conductive fibers are distributed among the support blocks and exposed from the gaps of the support blocks.

Preferably, in the aforementioned high thermal conductivity light emitting diode, the thermal conductive fibers are arranged and distributed on the board body along a direction substantially perpendicular to the light emitting unit.

Preferably, in the aforementioned high thermal conductivity light-emitting diode, the thermal conductivity of the thermal conductive fiber is between 380 and 2000 W/m·K.

Preferably, in the aforementioned high thermal conductivity light-emitting diode, the thermal conductive fibers are selected from metal fibers, high thermal conductive carbon fibers, or graphitized vapor deposition carbon fibers.

Preferably, in the aforementioned high thermal conductivity light-emitting diode, the plate body is selected from metal, alloy metal, thermosetting polymer or thermoplastic polymer.

Preferably, the above-mentioned high thermal conductivity light-emitting diode, wherein the constituent material of the board body is selected from one of the following groups: silver, aluminum, copper, tin, antimony, aluminum oxide, phenolic resin, furan resin, polysilicon Oxygen resin, epoxy resin.

Preferably, in the aforementioned high thermal conductivity light-emitting diode, the board body has several holes, and the heat-conducting fibers are partially exposed from the holes.

Preferably, the above-mentioned high thermal conductivity light-emitting diode, wherein the light-emitting unit includes a first-type semiconductor layer disposed on the heat-conductive substrate, an active layer formed on the first-type semiconductor layer, and a cover covering the The second-type semiconductor layer on the active layer, the electrode unit has a bottom electrode between the heat-conducting substrate and the light-emitting unit, and a top electrode located on a top surface of the light-emitting unit.

Preferably, the above-mentioned high thermal conductivity light-emitting diode, wherein the light-emitting unit includes a first-type semiconductor layer disposed on the heat-conductive substrate, an active layer partially covered on the first-type semiconductor layer, and a cover Assuming the second type semiconductor layer on the active layer, the electrode unit has a bottom electrode formed on a surface of the first type semiconductor layer, and a top electrode formed on a surface of the second type semiconductor layer.

The beneficial effect of the present invention is that: the thermal energy generated when the light-emitting unit emits light is guided away from the light-emitting unit through the heat-conducting fiber of the heat-conducting substrate, so as to improve the light-emitting efficiency.

Description of drawings

FIG. 1 is a schematic diagram illustrating a conventional light-emitting diode;

Fig. 2 is a schematic diagram illustrating a first embodiment of the high thermal conductivity light-emitting diode of the present invention;

Fig. 3 is a three-dimensional schematic diagram illustrating the arrangement of several heat-conducting fibers in the board body of the first embodiment;

Fig. 4 is a schematic perspective view illustrating another arrangement of the heat-conducting fibers in the board body;

FIG. 5 is a schematic diagram illustrating a vertical conduction state of the first embodiment;

Figure 6 is a schematic diagram illustrating another aspect of the thermally conductive substrate; and

FIG. 7 is a schematic diagram illustrating the board body of the second embodiment.

detailed description

The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

Referring to FIG. 2 together with FIG. 3 and FIG. 4 , a first embodiment of the high thermal conductivity light-emitting diode of the present invention includes a heat-conductive substrate 2 , a light-emitting unit 3 , and an electrode unit 4 .

The heat-conducting substrate 2 includes a board body 21 and several heat-conducting fibers 22 scattered on the board body 21 . The board body 21 has a base surface 211 and a bottom surface 212 opposite to the base surface 211 . The material of the plate body 21 is selected from metals, alloy metals, thermosetting polymers or thermoplastic polymers, such as but not limited to one of the following groups: silver, aluminum, copper, tin, antimony, aluminum oxide, phenolic resin, furan resin, silicone resin, epoxy resin. And at least a part of the heat conducting fiber 22 is exposed outside the board body 21 .

The thermally conductive fiber 22 is selected from fibers with a thermal conductivity not less than 380W/m·K, and the thermally conductive fiber 22 suitable for the first embodiment has a thermal conductivity between 380 and 2000W/m·K, and is selected from metal fibers (metal fiber), high thermal conductivity carbon fiber (high thermal conductivity carbon fiber), or graphitized vapor deposition carbon fiber (Graphitized VGCF).

In detail, the heat-conducting fibers 22 can be arranged and distributed on the board body 21 along a direction substantially perpendicular to the light-emitting unit 3; they can also be arranged in a staggered weaving manner and have a porous structure, such as but not limited to As shown in FIG. 3 , it is distributed on the board body 21 in a staggered weaving manner (the board body 21 is indicated by a dotted line in FIG. 3 ), or as shown in FIG. 4 , along a line substantially perpendicular to the first type semiconductor layer. The vertical direction Z of 31 extends. Wherein, when the heat-conducting fibers 22 are stacked along a vertical direction Z in a staggered manner (as shown in FIG. 3 ), the heat-conducting fibers 22 arranged in the X-Y plane direction will have the best heat conduction effect; and when The thermally conductive fibers 22 extend along the vertical direction Z, and the thermally conductive substrate 2 has excellent thermal conductivity in the vertical direction Z. Preferably, the thermal conductivity of the thermally conductive substrate 2 along the arrangement direction of the thermally conductive fibers 22 is not less than 300 W/m·K.

More specifically, the heat-conducting fiber 22 can be exposed from any part of the board body 21 to directly contact the outside world, so as to increase the heat dissipation of the heat-conducting substrate 2 as a whole. Preferably, the heat-conducting fiber 22 can be exposed from the base surface 211 and the bottom surface 212 of the board body 21 respectively, or from the base surface 211 and the bottom surface 212 of the board body 21 at the same time. When the heat-conducting fiber 22 is exposed from the base surface 211 of the board body 21, the light-emitting unit 3 can be in direct contact with the heat-conducting fiber 22, accelerating the conduction of heat energy generated by the light-emitting unit 3 to the heat-conducting substrate 2; When the heat-conducting fibers 22 are exposed from the bottom surface 212 of the board body 21, the efficiency of conducting heat energy from the heat-conducting substrate 2 away from the light-emitting unit 3 and dissipating to the outside can be improved; more preferably, the heat-conducting fibers 22 can also At the same time, the base surface 211 and the bottom surface 212 of the board body 21 are exposed, so that the heat conduction and heat dissipation effects can be further enhanced. In this embodiment, as shown in FIG. 3 , the heat-conducting fibers 22 are stacked and arranged in multiple layers and distributed on the board body 21 , and are respectively exposed from the base surface 211 and the bottom surface 212 of the board body 21 as an example. Explain.

The light-emitting unit 3 is disposed on the base surface 211 of the board body 21 and includes a first-type semiconductor layer 31 disposed on the heat-conducting substrate 2 and an active layer 32 partially covering the first-type semiconductor layer 31 , and a second-type semiconductor layer 33 covering the active layer 32 . The electrode unit 4 is electrically connected with the light-emitting unit 3, and is used to provide electric energy to make the light-emitting unit 3 emit light. The electrode unit 4 may have a bottom electrode between the heat-conducting substrate 2 and the light-emitting unit 3, and a The top electrode of a top surface of the light-emitting unit 3; may also have a bottom electrode 41 formed on a surface of the first type semiconductor layer 31, and a top electrode formed on a surface of the second type semiconductor layer 33 electrode 42. It can be seen from the above structure that the first embodiment is in the horizontal conduction state as shown in FIG. 2 . Since the structure of the light-emitting diode and the selection of related materials are well known in the art and are not the focus of this technology, no further description is given here. In the first embodiment, the first-type semiconductor layer 31, the active layer 32, the second-type semiconductor layer 33, and the electrode unit 4 are respectively made of n-type gallium nitride layer, multiple quantum well layer, p type gallium nitride layer, and gold as an example for illustration.

Referring to Figures 4 and 5, when the number of the heat-conducting fibers 22 in the heat-conducting substrate 2 is sufficient, the heat-conducting substrate 2 can also be used for electrical conduction, therefore, the heat-conducting substrate 2 with thermal and electrical properties can also be directly arranged Under the light-emitting unit 3, a light-emitting diode in a vertical conduction state is obtained. It should be noted that the more the heat-conducting fibers 22 are contained, the electrical conductivity can be improved, but too much heat-conducting fibers 22 will reduce the covering property of the board body 21 on the heat-conducting fibers 22, making it difficult to shape. Preferably, the heat-conducting fiber 22 accounts for 10% to 60% of the volume of the heat-conducting substrate 2 . Specifically, if the board body 21 is made of epoxy resin, the volume percentage of the thermally conductive fibers 22 is between 10% and 60%, preferably, the volume percentage of the thermally conductive fibers 22 is between 30%. % to 60%; if the board body 21 is made of aluminum, the volume percentage of the heat conducting fiber 22 is between 10% and 35%. More specifically, when the board body 21 is made of epoxy resin and the volume percentage of the heat-conducting fibers 22 is 50%, the resistivity of the heat-conducting substrate 2 can reach 0.0011Ω·cm.

When electric energy is supplied from the electrode unit 4 to activate the light emitting unit 3, especially for high-power light emitting diodes, since the heat conducting fiber 22 of the heat conducting substrate 2 directly contacts the light emitting unit 3, the light emitting unit 3 emits light The huge heat energy generated during the process can be conducted away from the light-emitting unit 3 through the heat-conducting fiber 22 of the heat-conducting substrate 2; and the heat energy can be further conducted to the outside through the heat-conducting fiber 22 exposed outside the bottom surface 212, thus having an excellent cooling effect. In addition, the heat-conducting fibers 22 that are exposed on the board body 21 but not covered by the board body 21 can also be bonded together by carbon particles to maintain a complete heat-conducting channel and avoid existing heat-conducting fibers or particles. The problem of component contamination caused by mixing and dropping.

In addition, it should be supplemented that, in order to improve the heat dissipation of the heat-conducting substrate 2, the board body 21 may further have other different hollow structures, so that the heat-conducting fibers 22 may be exposed from other positions of the board body 21. , so as to increase the contact area between the heat-conducting fiber 22 and the board body 21 or the contact area with the outside, so as to improve the overall heat conduction and heat dissipation of the heat-conducting substrate 2 .

The heat-conducting fibers 22 can be exposed from the side edges of each crystal grain when the light-emitting diodes are diced. Alternatively, a part of the structure of the board body 21 may be removed by laser to expose the heat-conducting fibers 22 to the outside, and there is no special limitation. For example, referring to FIGS. 5 and 6, part of the structure of the board body 21 can be removed by laser, so that the board body 21 forms a hollow structure with a plurality of support blocks 214 spaced apart from each other. In this way, the heat-conducting fiber 22 is Distributed between the support blocks 214 and exposed from the gaps between the support blocks 214, the contact area between the heat-conducting fibers 22 and the board body 21 and the outside world can be increased to improve the heat dissipation of the heat-conducting substrate 2; And by adjusting the contact area between the light-emitting unit 3 and the heat-conducting fiber 22 , the epitaxial effect of the light-emitting unit 3 epitaxially formed from the heat-conducting substrate 2 can also be optimized.

A second embodiment of the high thermal conductivity light-emitting diode of the present invention is substantially the same as the first embodiment, the difference is that, referring to FIG. (shown in FIG. 3 ) are distributed on the board body 21 and partially exposed from the hole 213 . Through the holes 213 , the heat-conducting fibers 22 can be exposed to the outside world, so as to have excellent heat conduction and heat dissipation properties. In addition, the weight per unit volume of the board body 21 can also be reduced.

Specifically, the board body 21 is selected from thermosetting or thermoplastic polymer materials suitable for foam molding, such as epoxy resin, phenolic resin, and furan resin, etc., obtained through physical foaming or chemical foaming. . Since the related process of foaming by using polymer materials is known in the technical field, no further description is given here. In this embodiment, the board body 21 is obtained by chemical foaming. It should be further explained that the purpose of the holes 213 is to allow the heat-conducting fibers 22 to contact the outside through these holes 213, and to reduce the weight per unit volume of the board body 21, however, although the more holes 213 , the more the heat-conducting fiber 22 is in contact with the outside, the more heat dissipation can be increased and the weight per unit volume will be lighter. However, too many holes 213 will also affect the mechanical strength of the board body 21. Therefore, in terms of thermal conductivity, In consideration of overall weight and mechanical strength, preferably, the density of the board body 21 is between 0.4 g/cm ³ and 0.9 g/cm ³ .

To sum up, the high thermal conductivity light-emitting diode of the present invention forms the light-emitting unit 3 directly on the thermally conductive substrate 2 with high thermal conductivity and heat dissipation. Since the thermally conductive substrate 2 has thermally conductive fibers 22 with high thermal conductivity, And the heat-conducting fiber 22 will be exposed to the outside, therefore, the heat energy generated by the light-emitting unit 3 when it is actuated is quickly guided away from the light-emitting unit 3 through the heat-conducting fiber 22 and dissipated to the outside, which can have excellent heat dissipation In addition, by further forming the board body 21 into a hollow or hole 213 structure, not only the heat conduction and heat dissipation of the heat conduction substrate 2 can be improved, but also the weight per unit volume of the board body 21 can be reduced.

Claims (13)

1. a high heat conduction light-emittingdiode, comprise a piece of heat-conducting substrate, one be arranged at Luminescence unit on this heat-conducting substrate, and one electrically connect with this luminescence unit, is used for providing Electric energy makes the electrode unit that this luminescence unit is luminous；It is characterized in that: this heat-conducting substrate includes The heat conducting fiber that one plate body is scattered in this plate body with several, this plate body has one Basal plane, and a bottom surface being in reverse to this basal plane, and described heat conducting fiber is at least some of This is external to be exposed to this plate, and wherein, this luminescence unit is disposed on the basal plane of this plate body On.

High heat conduction light-emittingdiode the most according to claim 1, it is characterised in that: institute Stating heat conducting fiber is to arrange in weaving mode and have cellular structure.

High heat conduction light-emittingdiode the most according to claim 1, it is characterised in that: institute State heat conducting fiber exposed from this basal plane.

High heat conduction light-emittingdiode the most according to claim 3, it is characterised in that: institute State that heat conducting fiber is exposed from this bottom surface and direct and extraneous contact.

High heat conduction light-emittingdiode the most according to claim 1, it is characterised in that: should Plate body also has several bracer being spaced, and described heat conducting fiber is distributed in described Between bracer, and expose from the gap of described bracer.

High heat conduction light-emittingdiode the most according to claim 1, it is characterised in that: institute Stating heat conducting fiber is in this plate along a direction arranged distribution vertical with this luminescence unit essence Body.

High heat conduction light-emittingdiode the most according to claim 1, it is characterised in that: institute State the heat conductivity of heat conducting fiber between 380 to 2000W/m K.

High heat conduction light-emittingdiode the most according to claim 7, it is characterised in that: institute State heat conducting fiber and be selected from metallic fiber, highly-conductive hot carbon fiber, or graphitization vapour deposition carbon is fine Dimension.

High heat conduction light-emittingdiode the most according to claim 1, it is characterised in that: should Plate body is selected from metal, alloying metal, thermosetting polymer or thermal plastic high polymer.

High heat conduction light-emittingdiode the most according to claim 9, it is characterised in that: should The constituent material of plate body be selected from following group one of which: silver, aluminum, copper, stannum, antimony, Aluminium oxide alloy, phenolic resin, furane resins, polysilicone, epoxy resin.

11. high heat conduction light-emittingdiodes according to claim 1, it is characterised in that: should Plate body has several hole, and described heat conducting fiber is from described hole partial denudation.

12. high heat conduction light-emittingdiodes according to claim 1, it is characterised in that: should Luminescence unit includes first type semiconductor layer being arranged on this heat-conducting substrate, a shape Become the active layers in this first type semiconductor layer, and a lid sets second in this active layers Type semiconductor layer, this electrode unit has one between this heat-conducting substrate and this luminescence unit Hearth electrode, and the top electrode of an end face being positioned at this luminescence unit.

13. high heat conduction light-emittingdiodes according to claim 1, it is characterised in that: should Luminescence unit includes first type semiconductor layer being arranged on this heat-conducting substrate, a portion Divide and be covered on the active layers in this first type semiconductor layer, and a lid sets in this active layers Second-Type semiconductor layer, this electrode unit has one and is formed at this first type semiconductor layer The hearth electrode on one surface, and the top electricity on a surface being formed at this Second-Type semiconductor layer Pole.