KR101318288B1 - Heat radient insulating liquid filled in led lighting device and led lighting device using the same - Google Patents

Abstract

The present invention 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., dimethyl silicone oil, methyl panyl silicone oil, and poly methyl An insulating heat dissipating solution filled in a housing of an LED lighting device for absorbing and dissipating heat generated from the LED package of the LED lighting device, comprising a mixture of one or two or more of hydrogen siloxanes.

Description

HEAT RADIENT INSULATING LIQUID FILLED IN LED LIGHTING DEVICE AND LED LIGHTING DEVICE USING THE SAME}

The present invention is excellent heat dissipation, and can be solved the heat problem of the LED lighting apparatus at a low cost, and relates to an insulating heat dissipating liquid filled in the housing of the LED lighting apparatus and the LED lighting apparatus using the same.

Light-emitting diode (LED) incandescent lamps are attracting attention as a light bulb that can generate a brightness similar to that of conventional incandescent lamps at low power.

However, in the case of LED incandescent lamps used in various fields such as home lighting, office lighting, factory lighting, streetlight, headlight, landscape lighting, and leisure facilities, LED incandescent lamps are driven by currents and voltages different from those of existing incandescent lamps. There is a problem in that all the power facilities must be replaced. In addition, LED incandescent lamps have a drawback that heat generated from LEDs must be efficiently dissipated.

The heat generation problem in the LED lighting apparatus not only shortens the lifetime of the LED package itself but also shortens the lifetime of the power supply module that supplies power to the LED and lowers the luminous efficiency, .

In recent years, a large metal heat sink is attached to the LED lighting device to dissipate the heat of the LED and the power supply module. Various shapes and materials have been proposed to increase the heat radiation efficiency.

As an example of the method, a method has been proposed in which a heat dissipation liquid is filled in an LED lighting device to release heat generated by the LED with the heat dissipation liquid. Or, there was a problem exploding according to the heat of the LED. In addition, as time passes, transparency may be degraded, thereby preventing a desired luminance from being exhibited.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has an insulating property against electricity, non-reactivity with a substrate, high transmittance, low manufacturing cost, and excellent thermal conductivity as a heat transfer medium. It is to provide an insulating heat dissipation and an LED lighting device using the same.

Insulating heat dissipation filled in the housing of the LED lighting device for absorbing and dissipating heat generated from the LED package of the LED lighting device, which is an embodiment of the present invention, is non-toxic and non-reactive with respect to the LED package. And a mixture of one or more of dimethyl silicone oil, methyl panyl silicone oil, and poly methyl hydrogen siloxane, having a convective heat transfer coefficient of 15000-70000 (W / m ² K) at 80 ° C. at 80 ° C.

According to one embodiment of the present invention, the thermal conductivity of the 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 of one embodiment example of the invention, the viscosity of the insulating heat-dissipating liquid, can be from ^{25 ℃, 0.65mm 2 / sec -10} 6 mm 2 / sec.

According to one embodiment of the present invention, the dimethyl silicone oil, methyl phenyl silicone oil, and polysilica may further include a liquid silica, to fill the pores between the molecules of the siloxane.

According to one embodiment of the present invention, the refractive index of the insulating heat dissipating solution with respect to the sodium D line may be 1.374-1.392 or less at 2.0CS or less and 1.398-1.404 at 10CS or more.
In another embodiment, the LED lighting device, the housing of the cavity structure; A light emitting diode package installed in the housing; A power supply module for supplying external AC power to the LED package; A support structure for fixing the light emitting diode package and the power supply module; And a light-transmitting insulating heat dissipating liquid which dissipates heat generated from the light-emitting diode package and the power supply module by filling the housing having the cavity structure and impregnating the LED package and the power supply module in the housing. is, and the convective heat transfer coefficient at 80 ℃ in ^{20 ℃ 15000-70000 (W / m 2} K), a viscosity of, at ^{25 ℃, 0.65mm 2 / sec -10} 6 mm 2 / sec in, dimethyl silicone oil, methyl A liquid silica comprising a phenyl silicone oil, and a mixture of one or two or more of poly methyl hydrogen siloxane, to fill voids between each molecule of the dimethyl silicone oil, methyl phenyl silicone oil, and poly methyl hydrogen siloxane. Included; . ≪ / RTI >
According to an aspect of another embodiment of the present invention, the lighting device may further include a lens attached to the front surface of the light emitting diode package to diffuse the light emitted from the LED.
According to another embodiment of the present invention, the thermal conductivity of the insulating heat dissipating liquid may be 1.9 × 10 ^−4-4.2 × 10 ⁻¹ (Cal / cm · sec · ° C.).

When the heat dissipating liquid according to an embodiment of the present invention having the above-described configuration is used in the LED lighting device, the manufacturing cost is low, it is non-toxic and environmentally friendly, and the heat dissipation efficiency is excellent because of high thermal conductivity and heat transfer coefficient, and chemically Since it is non-reactive with a board | substrate etc., it becomes possible to ensure the outstanding durability to a lighting apparatus.

1 is a perspective view of a lighting apparatus according to an embodiment of the present invention.

Hereinafter, an insulating heat dissipation liquid filled in a housing of an LED lighting apparatus according to the present invention and an LED lighting apparatus using the same will be described in detail with reference to the accompanying drawings. In the following description, the bulb-type LED lighting device is described as an example of a lighting device filled with an insulating heat dissipating liquid, which is an embodiment of the present invention. However, the present invention is not limited thereto, and a cylindrical (fluorescent lamp) LED lighting device or a flat plate type is provided. It will be appreciated that an insulating heat dissipation liquid, which is an embodiment of the present invention, may also be used in a lighting device.

1 is a perspective view showing an embodiment of a light emitting diode lighting device according to the present invention. Fig. 1 shows a direct current type LED lighting apparatus.

1, the LED lighting apparatus includes a base 1, a housing 2, an AC power supply line 3, a power supply module 4, a DC power supply line 5, a light emitting diode package 6, , A lens (7), and a heat dissipating liquid (9).

The base 1 has a spiral protrusion structure that can be coupled to a common incandescent socket and includes a power terminal for making electrical connection with an external AC power source. The material of the base 1 is an electrically conductive metal.

The bulb-type housing 2 is hermetically sealed so that the heat dissipating liquid 9 can be confined in the housing cavity 8, and the material thereof is glass or plastic. The plastic housing 2 has the advantage of minimizing damage due to external impact. Depending on the lighting characteristics, a light diffusion coating may be applied inside or outside the bulb-type housing 2, or a light diffusion film may be attached to the outside. A nanopattern may also be formed on the surface of the housing for light diffusion. Attaching the light diffusing film to the bulb-shaped housing 2 can minimize the scattering of the glass during external impact.

The AC power supply line 3 is mainly a copper wire enamel coated with a power supply line for supplying the AC power supplied from the outside of the lighting apparatus according to the present invention to the power supply module 4.

As shown in FIG. 3, the power supply module 4 is a device that supplies AC power supplied from the outside of the lighting device to the DC power supply in accordance with the characteristics of the light emitting diode package 6. The AC power supply module 4 includes an AC- A rectifying circuit 12 for supplying a voltage and a dimming circuit 13 for adjusting the brightness of light by adjusting the amount of the DC voltage.

The DC power lead-in wire 5 is mainly a copper wire enamel coated with a power supply line for supplying the DC power supplied from the power supply module 4 to the LED package 6.

The light emitting diode package 6 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 light emitting diode package 6 mainly uses a white LED as a light emitting source, but red, blue, and green may be used individually or in combination according to illumination characteristics.

The lens 7 is mounted on the front surface of the light emitting diode package 6 and has a function of collecting or diffusing light emitted from the light emitting diode package 6 according to illumination characteristics. The lens 7 is made of plastic and is attached to the surface of the lens manufactured for light diffusion by using an optical film or by applying a light diffusing agent coating or a light diffusion nano pattern.

In FIG. 1, the support structure 40 fixes the LED package 6 and the power supply module 4. That is, the light emitting diode package 6 serves to prevent shaking of the power supply module 4.

The heat dissipating solution 9 radiates heat generated from the power supply module 4 and the light emitting diode package 6 to the outside of the housing 2 and emits light emitted from the light emitting diode package 6 out of the housing 2. Has the function. Therefore, the heat radiating solution 9 should be equipped 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.

Accordingly, the heat dissipating solution 9 used in the present invention is a straight dimethylsilicone (dimetylsilicon oil), methylphenylsilicone oil (methylphenyl silicon oil) or polymethyl hydrogen of the polydimethylsiloxane (Polydemetylsiloxane) type (polymethyl hydrogen siloxane) or a mixture of two or more thereof.

Physical and chemical characteristics of the heat radiation solution 9 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 a general metal, but due to the convection effect of doubling the energy transfer of molecular energy, the heat release effect to the external system becomes very high.

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, the heat radiation solution 9 according to the present invention has a large convection effect (convetion effect) is significantly higher heat dissipation efficiency than other materials.

[Thermal Conductivity]

The thermal conductivity of the insulating heat dissipating solution 9 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 is more than 60 ° C. when the external temperature is 20 ° C., the LED package may be thermally shocked and its durability may be rapidly deteriorated.

 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 6 and the power supply module 4. 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 6 and the power supply module 4 is made smooth.

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 dissipation solution 9 according to an embodiment of the present invention, the viscosity of the insulating heat dissipation solution 9 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 solution 9 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 rises 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 solution 9, 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 占 폚 or higher. 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 dissipating solution 9 according to the embodiment of the present invention has no chemical reaction 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.

When the heat dissipating liquid according to an embodiment of the present invention having the above-described configuration is used in the LED lighting device, the manufacturing cost is low, it is non-toxic and environmentally friendly, and the heat dissipation efficiency is excellent because of high thermal conductivity and heat transfer coefficient, and chemically Since it is non-reactive with a board | substrate etc., it becomes possible to ensure the outstanding durability to a lighting apparatus.

The insulation heat dissipation liquid and the LED lighting device filled in the housing of the LED lighting device described above are not limited to the configuration and method of the above-described embodiments, but the embodiments may be modified in various ways. All or some of the embodiments may be optionally combined.

1: Base 2: Housing
3: AC power supply line 4: Power supply module
5: (DC) power supply lead 6: LED package
7: Lens 8: Incandescent housing joint
9: heat radiation liquid (dot form)

Claims (9)

An insulating heat dissipating solution filled in a housing of the LED lighting device for absorbing and dissipating heat generated from the LED package of the LED lighting device,
Non-toxic, non-reactive with respect to the LED package, the convective heat transfer coefficient is 15000-70000 (W / m ² K) at 20 ℃ to 80 ℃, the viscosity of the insulating heat dissipation, at 25 ℃, 0.65mm ² / dimethyl silicone oil, methyl phenyl silicone oil, and a mixture of one or more of polymethyl hydrogen siloxane, wherein the dimethyl silicone oil, methyl phenyl silicone oil, and poly methyl hydrogen are sec-10 ⁶ mm ² / sec. The insulating heat dissipation liquid further containing 1-3 weight% liquid silica for filling the space | gap between each molecule of a siloxane.
The method of claim 1,
The thermal conductivity of the said insulating heat dissipation liquid is 1.9 * 10 <^-4> -4.2 * 10 <^-1> (Cal / cm * sec * degreeC).
The method of claim 1,
The specific gravity of the said insulated heat dissipation liquid is 0.76-1.10 in 25 degreeC.
delete delete The method of claim 1,
The refractive index with respect to the sodium D line of the said heat insulating liquid is 1.374-1.392 in 2.0CS or less, and 1.398-1.404 in 10CS or more. A hollow housing;
A light emitting diode package installed in the housing;
A power supply module for supplying external AC power to the LED package;
A support structure for fixing the light emitting diode package and the power supply module; And
The transparent insulating heat dissipation liquid filled in the housing of the cavity structure to impregnate the light emitting diode package and the power supply module in the housing, thereby dissipating heat generated from the light emitting diode package and the power supply module. , and the convective heat transfer coefficient at 80 ℃ in ^{20 ℃ 15000-70000 (W / m 2} K), a viscosity of, at ^{25 ℃, 0.65mm 2 / sec -10} 6 mm 2 / sec in, dimethyl silicone oil, methyl paenil Silicone oil, and a mixture of one or two or more of poly methyl hydrogen siloxane, and further comprising liquid silica to fill voids between each molecule of the dimethyl silicone oil, methyl panyl silicone oil, and poly methyl hydrogen siloxane. doing; Including, LED lighting device.
The method of claim 7, wherein
And a lens attached to the front surface of the light emitting diode package to diffuse the light emitted from the LED.
The method of claim 7, wherein
The thermal conductivity of the said insulated heat dissipation liquid is the LED illuminating device of 1.9 * 10 <^-4> -4.2 * 10 <^-1> (Cal / cm * sec * degreeC).

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