KR101321581B1 - Light emitting diode lamp - Google Patents

Abstract

The present invention provides a power supply terminal including a power supply terminal capable of electrical connection with an external AC power supply; A housing having a cavity structure coupled to the power terminal; A light emitting diode package installed in the housing; A power supply module for supplying the external AC power to the light emitting diode package; A translucent insulating heat dissipating liquid filling the housing of the cavity structure by dipping the LED package and the power supply module in the housing to dissipate heat generated from the LED package and the power supply module; And a metal heat sink attached to an upper portion of the housing and dissipating heat of the light-transmitting insulating heat dissipation liquid to the outside.

Description

Light Emitting Diode Lighting Equipment {LIGHT EMITTING DIODE LAMP}

The present invention relates to a light emitting diode lighting device having excellent heat dissipation effect and economic efficiency.

In place of the existing incandescent lamps or fluorescent lamps, the development of lighting equipment using a light emitting diode (LED) as a white light source is increasing. LED (Light Emitting Diode) is a device where electrons and holes meet and emit light at a p-n semiconductor junction (p-n junction) by current application. Such an LED is used in the form of a bare chip or in a package structure. Often, the LED in the form of a bare chip is referred to as an 'LED chip', and the LED in a package structure is referred to as an 'LED package'. Such LEDs are advantageous because they are reliable, easy to modulate, and stable in operation.

A white light-emitting lighting device that provides illumination of white light using a white LED has been proposed in the past. According to the needs of the user, the purpose of use, the use space, or the like, another kind of white light-emitting lighting apparatus having a unique color temperature is selected and used. Among them, white light-emitting lighting apparatuses that provide white light of daylight or warm white light are widely used.

 On the other hand, in the conventional white light emitting device, due to the LED lighting process or the temperature rise around the LED, the color change of the light, that is, the change in the color temperature due to the change in the wavelength band of the light may be caused. For example, a lighting device made to provide warm white white illumination may emit light that has been changed to a bluish wavelength by increasing temperature. This is pointed out as a big problem in that it loses the lighting characteristics of the original lighting device. In addition, the heat generation during the LED lighting process is to shorten the life of the lighting equipment, it is very necessary to have excellent heat dissipation characteristics for the LED development in that it can create a risk of fire or burn.

In particular, in the case of the 100W high-power LED lighting device, the amount of heat generated is too high, the lighting characteristics are lost, and the life is greatly shortened, and efforts to release heat are further required.
Reference literature: Patent Publication 2010-0112831 (LED heat dissipation lamp)

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and is to provide a light emitting diode lighting device capable of lowering the manufacturing cost and increasing economic efficiency and increasing heat dissipation efficiency to extend the guaranteed life of the LED lighting device.

LED lighting device according to an embodiment of the present invention for solving the above problems, the power supply terminal capable of electrical connection with an external AC power supply; A housing having a cavity structure coupled to the power terminal; A light emitting diode package installed in the housing; A power supply module for supplying the external AC power to the light emitting diode package; A translucent insulating heat dissipating liquid filling the housing of the cavity structure by dipping the LED package and the power supply module in the housing to dissipate heat generated from the LED package and the power supply module; And a metal heat sink attached to an upper portion of the housing to release heat of the light-transmitting insulating heat dissipation liquid to the outside.

According to an aspect of an embodiment of the present invention, the housing is cylindrical, the cross section of the metal heat sink may have a plurality of protruding structure.

According to one embodiment of the present invention, the metal heat sink may be formed by bending a plurality of times while heat treating the aluminum plate.

According to one embodiment of the present invention, the light-transmitting heat dissipating liquid may include an insulating liquid and thermally conductive particles dissolved in the insulating liquid. Herein, the thermally conductive particles may be one of purified carbon nanotube particles, amorphous carbon nanotube particles, graphite particles, and ceramic particles.

According to one embodiment of the present invention, the insulating liquid may include propylene glycol and ultrapure water.

According to one embodiment of the present invention, the insulating liquid may include a surfactant for dissolving the thermally conductive particles.

According to an embodiment of the present invention, the insulating liquid may include a transformer oil.

According to one embodiment of the present invention, the thermally conductive particles may have magnetic properties.

According to one embodiment of the present invention, the LED lighting apparatus may further include an electromagnetic stirrer installed in the housing so that the thermally conductive particles can convection.

According to an aspect of an embodiment of the present invention, the electromagnetic stirrer may be an eddy coil or a toroidal magnetic coil.

According to one aspect of the present invention, the light-transmitting insulating heat dissipation liquid is non-toxic, non-reactive with respect to the LED package, and has a convective heat transfer coefficient of 15000-70000 (W / m ² K) at 20 ° C. to 80 ° C. And one or more of two or more of phosphorus, dimethyl silicone oil, methyl panyl silicone oil, and poly methyl hydrogen siloxane.

According to an embodiment of the present invention, the thermal conductivity of the translucent insulating heat dissipating liquid may be 1.9 × 10 ^−4-4.2 × 10 ⁻¹ (Cal / cm · sec · ° C.).

According to an embodiment of the present invention, the specific gravity of the insulating heat dissipating liquid may be 0.76-1.10 at 25 ° C.

According to one aspect an exemplary embodiment of the present invention, the viscosity of the light-transmitting heat insulation liquid, it can be from ^{25 ℃, 0.65mm 2 / sec -10} 6 mm 2 / sec.

According to an embodiment of the present invention, the light-transmitting insulating heat dissipating liquid may further include liquid silica for filling voids between the molecules of the dimethyl silicone oil, methyl panyl silicone oil, and polymethyl hydrogen siloxane. Can be.

According to an embodiment of the present invention, the refractive index of the light-transmitting insulating heat dissipating solution for the sodium D line may be 1.374-1.392 or less and 2.098-1.404 in 10CS or more.

According to an embodiment of the present invention having the above-described configuration, by cooling the heat generated in the light emitting portion and the circuit portion more quickly through the insulating liquid, and by quickly dissipating the heat of the heat radiation liquid to the outside through the metal heat sink By lowering the temperature of the lighting device to prevent thermal damage, it is possible to ensure the life of the light emitting diode.

In addition, according to an embodiment of the present invention, by further comprising thermally conductive particles in the insulating liquid, it is possible to enhance the heat conduction efficiency of the insulating liquid to enhance the heat radiation efficiency.

In addition, the thermally conductive particles are magnetic, and by installing an electromagnetic stirrer inside the housing to allow the insulating liquid to convection, it is possible to maximize the cooling effect on the heat generated in the light emitting portion and the circuit portion.

1 is a perspective view of a light emitting diode lighting device according to an embodiment of the present invention.
2 is a cross-sectional view of a light emitting diode lighting device according to an embodiment of the present invention.
3 is a cross-sectional view of a metal heat sink used in a light emitting diode lighting device of one embodiment of the present invention.
4 is a block diagram illustrating an electronic configuration of a light emitting diode lighting device according to an embodiment of the present invention.

Hereinafter, a light emitting diode lighting apparatus according to the present invention will be described in more detail with reference to the accompanying drawings.

1 is a perspective view of a light emitting diode lighting device according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a light emitting diode lighting device according to an embodiment of the present invention. As shown in FIG. 1 and FIG. 2, a light emitting diode lighting device according to an embodiment of the present invention includes a power supply terminal 11, a cylindrical housing 20, and an LED package 60 installed in the housing 20. A power supply module 50 for supplying power to the LED package 60 may include a light-transmitting insulating heat dissipation liquid 30, an electromagnetic stirrer 60, and a metal heat sink 70.

The power supply terminal 11 attached to the upper portion of the housing 20 has a protruding structure that can be coupled to an incandescent lamp socket or a fluorescent lamp socket, and enables electrical connection with an external AC power source.

The housing 20 has a cavity structure and is sealed to trap the heat dissipation liquid 30 therein, and the housing 20 is made of glass or plastic. The housing 20 made of plastic has an advantage of minimizing damage caused by external impact. However, the thermal conductivity of the housing 20 made of such plastic or glass is lower than that of metal. Heat generated in the LED package 60 or the power supply module is finally released to the outside through the housing 20, when the thermal conductivity of the housing 20 is low, the heat dissipation efficiency is sharply worsened, in particular, It is necessary to increase the thermal conductivity of the housing 20 in the luminaire which is installed outside such as a high output light emitting diode lighting device or a street lamp having a large amount of heat emission and has a large influence by the external temperature. Thus, in the present invention, a metal heat sink 70 having high thermal conductivity is attached to the housing 20. This will be described in detail with reference to FIG. 3.

On the other hand, according to the lighting characteristics of the lighting device may be a light diffusion coating inside or outside the housing 20, or a light diffusion film may be attached to the outside. In addition, nano-patterns may be formed on the surface of the housing 20 for light diffusion. Attaching the light diffusing film to the bulb-type housing can minimize the scattering of the glass during external impact.

The light emitting diode package 60 (mixed with LED package or LED package) includes a semiconductor device for converting electrical energy supplied from the power supply terminal 11 to light energy. LEDs are semiconductor devices, and all semiconductors have the ability to conduct current due to impurities in the internal structure (caused by a small amount of chemical additives). N-type impurities add extra electrons to the semiconductor, and P-type impurities produce "holes." Electrons, which are negatively charged particles, naturally move from high electrons (negative) to low electrons (positive). Inside the diode, N-type material is placed next to the P-type material, and when both are located between the electrodes, this structure allows current to flow from the N-type electrode to the P-type electrode in one direction only. As soon as electrons fall into holes, electrons emit energy in the form of photons, resulting in the emission of light as electrons move from one side of the diode to the other. Depending on the type of material used in the semiconductor, various wavelengths of light are generated and irradiated. The light emitting diode package 60 including a plurality of light emitting diodes may be a printed circuit board (PCB), a flexible printed circuit board (FPCB), or a chip on board (COB) in which one or more light emitting diodes are mounted according to lighting characteristics. .

The LED used in the LED package 60 mainly uses a white LED as a light emitting source, but red, blue, and green may be individually or mixed according to lighting characteristics.

The lens 41 is mounted on the front surface of the LED package 60 and has a function of collecting or diffusing light from the LED package 60 according to lighting characteristics. The lens 41 is made of plastic and used by attaching an optical film to the surface of the lens 41 manufactured for light diffusion, or applying a light diffusing agent coating or a light diffusion nano pattern.

Power supply module 50 is a device for supplying the AC power supplied from the outside of the luminaire to the DC power supply in accordance with the characteristics of the light emitting diode package 60 as shown in FIG. The main circuit is composed of a rectifier circuit and a dimming circuit capable of controlling the brightness of light by adjusting the amount of current of the DC voltage. This will be described in more detail with reference to FIG. 4.

 The light-transmitting insulating heat dissipating liquid 30 is generated from the light emitting diode package 60 and the power supply module 50 by immersing the light emitting diode package 60 and the power supply module 50 in the housing 20. It functions to dissipate heat. The insulating heat dissipation liquid 30 radiates heat generated from the power supply module 50 and the light emitting diode package 60 to the outside of the housing 20 and emits light emitted from the light emitting diode package 60 to the outside of the housing 20. Has the function to Therefore, the heat dissipation liquid 30 should be provided with all of heat dissipation, light transmittance, and electrical insulation. The light-transmitting insulating heat dissipating liquid 30 may include the insulating liquid and thermally conductive particles dissolved in the insulating liquid. The thermally conductive particles may include amorphous carbon nanotube particles, tablet nanotubes, graphite particles, It may comprise one of the ceramic particles. As the carbon nanotube particles, one of single-walled carbon nanotube particles, double-walled carbon nanotube particles, and multi-walled carbon nanotubes may be used. At this time, since the thermally conductive particles are contained in a very small amount, only the thermal conductivity effect can be raised while maintaining the characteristics of the insulating liquid. Particularly, in the case of unfixed carbon nanotubes, carbon nanotubes have a magnetic nature because they remain as catalysts for growing carbon nanotubes as carbon nanotubes at the stage before purification in the manufacturing process. As such, when the thermally conductive particles are magnetic, they are acted by an electromagnetic stirrer 60 to be described later, and convection occurs in the insulating liquid, thereby maximizing heat dissipation.

The electromagnetic stirrer 60 is installed in the housing 20 to form a magnetic field so that the thermally conductive particles, which are magnetic materials, can convection. As a result, the thermally conductive particles, which are magnetic materials of the heat-transparent heat-insulating insulating liquid in the housing 20, are convective, whereby the heat-insulating insulating liquid is convection. As a result, heat generated from the LED package 60 and the power supply module 50 may be better absorbed and radiated.

As the electromagnetic stirrer 60, an eddy coil or a toroidal magnetic coil may be used. The eddy coil is a low speed type, the toroidal magnetic coil is a high speed type, and the manufacturer can appropriately select it according to the degree of heat generation.

On the other hand, the metal heat sink 70 is attached to the outside of the housing 20. This is to be attached to the upper portion of the housing 20 to dissipate the heat dissipation insulating solution having a high temperature, so that the cross section has a protruding structure can enhance the air cooling effect.

This will be described in more detail in FIG.

3 is a cross-sectional view of a metal heat sink used in a light emitting diode lighting device according to an embodiment of the present invention. As shown, the cross section of the metal heat sink 70 may have a plurality of protrusion structures. That is, the metal heat sink 70 is formed by bending a plurality of times while heat treating an aluminum plate or a copper plate. As described above, by having a plurality of projecting structures, the contact area with the external air is widened, and accordingly, the heat dissipation effect is increased. That is, the heat of the housing 20 of the lighting device is released by the convection of air from the outside, where the total amount of heat is proportional to the surface area of the housing 20 or the metal heat sink 70. Therefore, when it has the above-mentioned protruding structure (heat radiating fin structure), heat dissipation efficiency will become high. In addition, in the present invention, as shown, since the housing 20 and the metal heat sink 70 are attached through the heat conductive adhesive layer 80 (thermal grease), the housing 20 and the metal heat sink 70 are attached. There is no gap between). As a result, the heat conduction efficiency from the housing 20 to the metal heat sink 70 is increased, and as a result, heat is smoothly emitted from the luminaire housing.

In FIG. 4, the electronic operation of the LED lighting apparatus according to the embodiment of the present invention having the above-described configuration will be described.

4 is a block diagram of a light emitting diode lighting apparatus according to an embodiment of the present invention. As shown in FIG. 4, the power supply module 50 of the LED lighting device includes an AC / DC converter (power converter) 11 for converting the AC power into DC power, and a rectifier circuit connected to the converter. Rectifier) and a dimming circuit that can control the current of the rectified DC power supply to the rectifier circuit. That is, the AC power from the external power source 1 is changed into a DC voltage and is supplied to the LED package 40, and accordingly, the LED package 40 emits light, wherein the LED package 40 further includes a dimming circuit. You will adjust the degree.

On the other hand, a coil is connected to the power supply module 50. When AC power from the power supply module 50 is supplied to the coil, a magnetic field is generated accordingly. Then, the flow of liquid is generated by the magnetic particles included in the heat dissipation liquid 30 affected by the magnetic field. Done. Since this liquid flow helps convection of the heat dissipation liquid 30, the heat dissipation efficiency is increased.

Hereinafter, the type and the physical and chemical properties of the heat dissipating liquid 30 used in one embodiment of the present invention will be described in detail.

The heat dissipation solution 30 radiates heat generated from the power supply module 50 and the light emitting diode package 60 to the outside of the housing 20 and emits light emitted from the light emitting diode package 60 to the outside of the housing 20. Has the function. Therefore, the heat dissipation liquid 30 should be provided with all of heat dissipation, light transmittance, and electrical insulation.

In more detail, 1) the thermal conductivity as a heat transfer medium should be excellent, 2) the state of molecular transport to transfer the heat energy (that is, the viscosity of the liquid phase must be high in motion with temperature, and 3) the molecular structure at high temperature 4) Excellent chemical resistance, chemical resistance (non-reactive) that does not occur chemical reaction, corrosion, ion exchange, etc. with other devices, 5) Excellent light transmittance, no change in refractive index at high temperature, 6) Refractive index is controlled freely, and there should be no haze phenomenon that gel or foreign substance is generated by self-synthesis or self-crosslinking. 7) High boiling point , Evaporation should not occur when operating at high temperature, and 8) rapid heat transfer should be made to the material surrounding the fluid (the fine powder by van der Waals' repulsion at the interface) There should be no voids), 9) The change should be small according to the temperature change, 10) The insulation of electric devices should be high, 11) It is environmentally friendly and non-toxic.

The insulating liquid contained in the heat dissipating liquid 30 is a liquid having an electric conductivity value of 0 and which is impossible to conduct electricity, and has no ionic components (DI water, propylene glycol, transformer oil, and thermal conductivity). It may contain one of these superior dimethyl silicone oils. Ultrapure water is pure water without any impurities except ions formed by removing all ions dissolved in the water and self-ionizing the water. There is no electrical conductivity. Propylene glycol is a material having excellent solubility, and thermally conductive particles described later are dissolved by this propylene glycol and are environmentally friendly in that they are transparent and non-toxic.

On the other hand, the heat dissipation solution 30 used in the present invention is a polydimethyl siloxane (Polydemetylsiloxane) of the straight nature of the dimethyl silicone oil (dimetylsilicon oil), methylphenyl silicon oil (methylphenyl silicon oil) or polymethyl hydrogen siloxane (Polymethyl hydrogen siloxane ) Or a mixture of two or more.

The physical and chemical characteristics of the heat dissipating solution 30 according to the embodiment of the present invention will be described as follows.

[Convective Heat Transfer Coefficient]

When the material of the heat dissipation device of the LED lighting device is a liquid phase, the thermal conductivity is not higher than that of the general metal, but the heat release effect to the external system is very high due to the convection effect that doubles the energy transfer of molecular energy.

Convective heat transfer coefficients according to convective heat transfer media are shown in the following table.

Convection heat transfer medium
(20 ° C-80 ° C) h.btu / hrft ² F h, W / (m ² K) Air (natural convection) 1-10 5-25 water 500-5000 2500-25000 oil 1000-20000 5000-50000 Examples of the present invention 3000-30000 15000-70000

As shown in FIG. 1, a straight-type dimethylsilicone oil, methylphenyl silicone oil, or polymethyl hydrogen siloxane among polydimethylsiloxane series according to an embodiment of the present invention, (W / m ² K) at 20 ° C and 80 ° C is higher than that of other media (air, water, common oil), resulting in a heat transfer effect high.

That is, since the heat dissipation solution 30 according to the present invention has a large convection effect, the heat dissipation efficiency is significantly higher than that of other materials.

[Thermal Conductivity]

The thermal conductivity of the insulating heat dissipation liquid 30 having the above-described configuration, which is one embodiment of the present invention, has a range of 1.9 × 10 ^−4-4.2 × 10 ⁻¹ (Cal / cm · sec · ° C.).

In general, when the operating temperature of the LED exceeds 20 ° C. when the external temperature is 20 ° C., the LED package 60 may be thermally shocked, and the durability may deteriorate rapidly.

 Thermal conductivity refers to the ability of energy to move between molecules. The higher the thermal conductivity, the higher the heat generated by the LED package 60 and the power supply module 50. This thermal conductivity has a very close proportional relationship with the viscosity, and if the thermal conductivity is higher than the upper limit value, the convective heat transfer coefficient is drastically deteriorated. In addition, when the thermal conductivity becomes lower than the above lower limit value, the heat transfer effect is so weak that the function of the heat medium is so weak that only the convection transfer is meaningless.

Therefore, in one embodiment of the present invention to have a thermal conductivity in the above range, the heat discharge of the LED package 60 and the power supply module 50 is smoothly made.

Meanwhile, in order to increase the thermal conductivity, it may further include liquid silica which is one embodiment of the present invention. The liquid silica is for filling voids between each molecule of the dimethyl silicone oil, methylphenyl silicone oil, and polymethylhydrogen siloxane. The liquid silica may be contained in an amount of about 1 to 3% by weight. This is determined by considering the change in specific gravity with respect to temperature.

[Viscosity]

Viscosity is related to the convective heat transfer effect and is much more than the heat transfer rate in the liquid phase device, which is one of the important factors of the heat transfer medium. Viscosity of the insulating heat dissipating liquid 30 according to an embodiment of the present invention, the viscosity of the insulating heat dissipating liquid 30 may be 0.65mm ² / sec -10 ⁶ mm ² / sec at 25 ℃. If the viscosity is higher than the upper limit value, the convective heat transfer effect is reduced (precisely, the film efficiency is reduced), and the heat transfer efficiency is reduced drastically. When the lower limit is set, the viscosity is too low, so that a liquid-phase intermolecular energy transfer molecular clearance with Si as a basic structure is generated, and the function as a heat transfer medium is reduced rapidly (intermolecular distance- Near the weak monomer - (degree of freedom, oscillation distance 1 / r2)), the effect of convective heat transfer is reduced without moving the medium and then reduced again.

[importance]

The specific gravity of the insulating heat dissipation liquid 30 according to an embodiment of the present invention may be 0.76 to 1.10 at 25 ° C. This specific gravity is closely related to the volume change with temperature change. In particular, when the lighting device operates at a room temperature of 20 ° C. in general, when the temperature of the LED package is increased to 60 ° C. or more, the life of the product is drastically reduced due to heat damage. That is, in the case of an interior lamp, the lamp has a usable range of 20 ° C to 60 ° C. If the specific gravity is out of the above range, the housing itself may be physically damaged due to rapid expansion and contraction.

[Other characteristics]

Insulating heat dissipation liquid 30, which is an embodiment of the present invention, is a mixture of one or two or more of dimethyl silicone oil, methyl phenyl silicone oil, and polymethyl hydrogen siloxane, and their boiling point is 800 deg. Therefore, when 60 ℃ is viewed as the maximum temperature of the operating temperature, there is no loss due to vaporization during the operation of the LED lighting device, thereby ensuring a semi-permanent life.

In addition, since the insulating heat dissipation liquid 30, which is an embodiment of the present invention, has chemical non-reactivity with respect to the substrate, the LED package module, the housing, and the like, there is no haze phenomenon due to the chemical reaction with the substrate, even if used for a long time. Parts life can be ensured.

In addition, since dimethyl silicone oil, methylphenyl silicone oil, and polymethylhydrogen siloxane are non-toxic, they are easy to handle and costly to dispose of.

In addition, the refractive index of the insulating heat dissipating liquid according to an embodiment of the present invention is maintained at 1.374 to 1.392 for the sodium D line, and at 1.398 to 1.404 for the 10 Cs or more. Accordingly, the light emitted from the LED package which is the light source is not distorted.

The LED lighting device described above may not be limitedly applied to the configuration and method of the embodiments described above, but the embodiments may be selectively combined with each or all of the embodiments so that various modifications may be made. It may be configured.

1: External power supply (AC power supply)
11: power terminal
20: housing (cylindrical)
30: heat dissipation liquid
41: lens
43: LED Package
50: power supply module
60 coil (electromagnetic stirrer)
70: metal heat sink
80: heat conductive adhesive layer

Claims (17)

A power supply terminal capable of electrical connection with an external AC power supply;
A housing having a cavity structure coupled to the power terminal;
A light emitting diode package installed in the housing;
A power supply module for supplying the external AC power to the light emitting diode package;
A translucent insulating heat dissipating liquid filling the housing of the cavity structure by dipping the LED package and the power supply module in the housing to dissipate heat generated from the LED package and the power supply module; And
And a metal heat sink attached to an upper portion of the housing and dissipating heat of the light-transmitting insulating heat dissipation liquid to the outside.
The method of claim 1,
The housing is cylindrical,
The cross-section of the metal heat sink has a plurality of projecting structure, LED lighting device.
3. The method of claim 2,
The metal heat sink is formed by bending a plurality of times while heat treating the aluminum plate.
The method of claim 3, wherein
The light-transmitting insulating heat dissipating liquid includes an insulating liquid and thermally conductive particles dissolved in the insulating liquid.
5. The method of claim 4,
The thermally conductive particles are one of purified carbon nanotube particles, unrefined carbon nanotube particles, graphite particles, and ceramic particles.
5. The method of claim 4,
The insulating liquid includes propylene glycol and ultrapure water.
5. The method of claim 4,
The insulating liquid includes a light emitting diode illuminating device comprising a surfactant for dissolving the thermally conductive particles.
5. The method of claim 4,
The insulating liquid, a transformer oil (transformer oil), LED lighting device.
5. The method of claim 4,
The thermally conductive particles have magnetic properties, light emitting diode lighting device.
The method of claim 9,
Further comprising an electromagnetic stirrer installed in the housing such that the thermally conductive particles can convection.
11. The method of claim 10,
The electromagnetic stirrer is an eddy coil or a toroidal magnetic coil.
The method of claim 1,
The light-transmitting insulating heat dissipation liquid is non-toxic, non-reactive with respect to the light emitting diode package, and has a convective heat transfer coefficient of 15000-70000 (W / m ² K) at 20 ° C. to 80 ° C., methyl phenyl silicone oil. And a mixture of one or two or more of poly methyl hydrogen siloxane.
13. The method of claim 12,
The thermal conductivity of the said transmissive insulating heat dissipation liquid is 1.9x10 <^-4> -4.2x10 <^-1> (Cal / cm * sec * degreeC).
13. The method of claim 12,
The specific gravity of the said translucent insulating heat dissipation liquid is 0.76-1.10 at 25 degreeC.
13. The method of claim 12,
The viscosity of the light-transmitting heat insulation liquid, in ^{25 ℃, 0.65mm 2 / sec -10} 6 mm 2 / sec is, the LED lighting device.
13. The method of claim 12,
The light-transmitting insulating heat dissipating liquid further comprises liquid silica for filling voids between each molecule of the dimethyl silicone oil, the methyl panyl silicone oil, and the polymethyl hydrogen siloxane.
13. The method of claim 12,
The refractive index with respect to the sodium D line of the said transparent insulating heat radiation liquid is 1.374-1.392 for 2.0CS or less, and 1.398-1.404 for 10CS or more.

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