JP2013026206A - Structure of led lighting fixture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure of an LED lighting fixture with extinction of heat improved.SOLUTION: The LED lighting fixture includes: at least one LED chip 200; a metal plate 204 having at least one LED chip arranged; an LED module 250 in electric contact with at least one LED chip; and a housing 206 in contact with the metal plate and having the LED module installed inside. The housing includes: a resin layer 205 with an internal surface and an external surface; and a metal layer 207 arranged on at least a part of the external surface of the resin layer so as to clad it in contact with the metal plate. The resin layer includes an electrically insulating thermoplastic resin composition, and the metal layer includes an aluminum alloy, and at the same time, has a thermal conductivity from at least 20 Watts per meter per Kelvin (W/m, K) to 40 W/m, K, and a thermal emissivity of 0.5 to 0.8.

Description

  Described herein is a light emitting diode (LED) luminaire comprising a two-layer housing having an inner resin layer that is completely or partially covered by an outer metal layer. This metal layer has a thermal conductivity of at least 20 watts per meter Kelvin (W / m, K) and a thermal emissivity of 0.5 to 0.8 and is in contact with the metal plate on which the LED chip is deployed. doing.

  Light emitting diode (LED) lighting fixtures provide high light intensity and a longer operating life than incandescent bulbs as light sources. LED lighting fixtures typically include an LED module and a housing for the module. The LED module is essentially a semiconductor and includes an LED chip (light emitting source) and a carrier for the chip. An LED chip is essentially a light bulb that has a built-in circuit driver instead of a filament or is electronically connected to an external circuit, and emits light when electricity passes through the LED module. Since the chip, ie the light source, is located within the module to some extent, if light is emitted from the chip for a long time, heat from the chip that can exceed 70 ° C. can be generated inside the module. As such, many conventional LED luminaires also include a structure that is thermally biased to effectively dissipate heat from the LED module—usually referred to as the LED control driver cover.

International Publication No. 2004/055248 Pamphlet

  The LED housing normally serves to dissipate the heat generated by the LED module and to serve as a structural support for the module and its circuitry. Although various structural arrangements of LED luminaires have been disclosed, there remains a need for an LED luminaire whose housing facilitates heat dissipation due to its configuration and component placement.

The solution provided here is
a. At least one LED chip;
b. A metal plate on which the LED chip is deployed;
c. An LED module in electrical contact with the LED chip;
d. A housing in contact with the metal plate, in which the LED module is disposed;
A light emitting diode (LED) lighting fixture comprising:
This housing
i) a resin layer having an inner surface and an outer surface;
ii) a metal layer disposed in a covering manner on at least a portion of the outer surface of the resin layer, the metal layer being in contact with the metal plate;
Including
The resin layer includes a thermoplastic resin composition,
The metal layer includes an aluminum alloy and has a thermal conductivity of at least 20 watts per meter Kelvin (W / m, K) to 40 W / m, K and a thermal emissivity of 0.5 to 0.8. Have
A light emitting diode (LED) lighting fixture.

  The invention will be more fully represented by the following drawings.

1 shows a cross-sectional view of a conventional LED lighting fixture according to the prior art. FIG. 3 shows a cross-sectional view of an LED luminaire described herein and shows an LED housing described herein. FIG. 3A shows a cross-sectional view of an LED luminaire that includes an LED housing having only a metal layer. 3B shows a cross-sectional view of an LED simulation test apparatus that simulates the thermal characteristics of the LED lighting fixture of FIG. 3A. FIG. 4A shows a cross-sectional view of an LED lighting fixture that includes an LED housing with only a polymer resin layer and no metallization layer. 4B shows a cross-sectional view of an LED simulation test apparatus that simulates the thermal characteristics of the LED lighting fixture of FIG. 4A. FIG. 5A shows a cross-sectional view of an LED lighting fixture as described herein including a two-part LED housing having a metal layer that completely covers the polymer resin layer. FIG. 5B shows a cross-sectional view of an LED simulation test apparatus that simulates the thermal characteristics of the LED lighting apparatus of FIG. 5A. FIG. 6A shows a cross-sectional view of an LED luminaire described herein, including a two-part LED housing that is a 25 mm long metal layer with a metal layer partially covering the resin layer. 6B shows a cross-sectional view of an LED simulation test apparatus that simulates the thermal characteristics of the LED lighting apparatus of FIG. 6A. FIG. 7A shows a cross-sectional view of an LED luminaire described herein, including a two-part LED housing that is a 20 mm long metal layer with a metal layer partially covering the resin layer. FIG. 7B shows a cross-sectional view of an LED simulation test apparatus that simulates the thermal characteristics of the LED lighting apparatus of FIG. 7A. The top perspective view of the test piece which is a rectangular test piece used as the comparative example 2 or 3 and is comprised only from a resin layer is shown. FIG. 2 shows a plan perspective view of a rectangular test piece used in Examples E1 and E4 having a resin layer completely covered with a metal layer.

Definitions The following definitions shall be used to interpret the meaning of the terms discussed herein and cited in the claims.
As used herein, the article “a” indicates more than one as well as one, and does not necessarily limit its associated noun to the singular.
As used herein, the terms "about" and "... or about ..." mean that the amount or value is the indicated value or approximate Can be the same or approximately the same as some other value. This term is intended to convey that similar values achieve the equivalent result or effect recited in the claims.
As used herein, the terms “comprises / comprising”, “includes / inclusions”, “has / having”, or any other variations thereof, Means non-exclusive inclusion. For example, a process, method, product or apparatus that includes a list of elements is not limited to only those elements that are listed, but other elements that are not explicitly listed, or other elements that are inherently unique. Can be included. Further, “or” means an inclusive “or” and not an exclusive “or”, unless expressly stated otherwise. For example, the condition “A or B (A or B)” is satisfied by any one of the following terms. That is, “A is true (or exists), B is false (does not exist)”, “A is false (or does not exist), and B is true (or exists)”, And “both A and B are true (or exist)”.
As used herein, the terms “comprises / comprising”, “includes / including”, “has / having”, “consisting essentially”. of) ”, and“ consisting of ”, or any other variations thereof, can mean either non-exclusive inclusion or exclusive inclusion.
Where these terms mean non-exclusive inclusion, the process, method, product or apparatus containing the list of elements is not limited to the listed elements, but is not explicitly listed. Or other elements that are inherently unique. Further, unless expressly stated otherwise, “or” means an inclusive “or” and not an exclusive “or”. For example, the condition “A or B (A or B)” is satisfied by any one of the following terms. That is, “A is true (or exists), B is false (does not exist)”, “A is false (or does not exist), and B is true (or exists)”, And “both A and B are true (or exist)”.
Where these terms mean relatively exclusive inclusion, these terms are intended to limit the scope of the claims to those listed materials or steps that substantially affect the novel elements of the invention. Restrict.
Where these terms mean completely exclusive inclusion, these terms exclude any element, step or component not explicitly recited in a claim.
As used herein, the term “article” means an unfinished or completed item, article or object, or an element or feature of an unfinished or completed item, article or object. As used herein, when a product is incomplete, the term “product” means any item, article, object, element, device, etc., and / or finished that will be included in the finished product. It can mean any item, article, object, element, device, etc. that will be further processed to become a product. As used herein, when a product is complete, the term “product” has been processed to complete, whereby an item, article, or object suitable for a particular use / purpose. , Element, device, etc.
Product is one or more elements or subassemblies that are partially completed and scheduled for further processing, or one or more elements that are assembled with other elements / subassemblies that together make up the finished product Or a subassembly can be included. Further, as used herein, the term “product” can mean a system or form of product.
As used herein, the term “Almite / Alumite coating” refers to an anode having the IUPAC name of “oxo (oxoalumanoxy) aluminume”, CAS Registry Number 90669-62-8 and Al ₂ O _3. It means an oxide film.
As used herein, the term “inner” means the placement of a resin layer as a housing layer closer to the LED module.
As used herein, the term “outer” refers to the placement of a metal layer as a layer placed on the side away from the LED module.
As used herein, the terms “overlying” and “overline” refer to the orientation of the metal layer relative to the resin layer in the LED luminaire housing described herein. The metal layer is disposed on and adjacent to the surface of the resin layer farthest from the LED module, thus representing the positioning of the metal layer as the outer layer of the housing.
As used herein, the terms “thermal conductive” and “thermal conductivity” are indicated by the symbol k and refer to the properties of the material's thermal conductivity. Heat transfer across a material with high thermal conductivity occurs at a faster rate than heat transfer across a material with low thermal conductivity. The thermal conductivity of the material varies with temperature. In general, the higher the average temperature of the material, the higher the thermal conductivity. The reciprocal of thermal conductivity is thermal resistivity and is represented by the symbol. Thermal conductivity is measured in units of W / m, K, ie watts per meter and Kelvin.
As used herein, the terms “thermal emissive”, “thermal emissivity” (usually represented by the symbol ε or e) generally refer to the surface of a material. It refers to the relative ability characteristics of a material to emit energy by radiation. It is the ratio of the energy emitted by the material to the energy emitted by the black body at the same temperature. A true blackbody has ε = 1, whereas the thermal emissivity of any real object will be ε <1. Emissivity is a dimensionless quantity. In general, the darker and blacker the material, the closer to 1 the thermal emissivity. As the reflectivity of the material increases, its emissivity decreases. The emissivity of highly polished silver is about 0.02.
As used herein, the term “electrically insulating” refers to the ability of a material to resist charge flow. Such a material is referred to as a dielectric. A typical index of electrical insulation performance is the volume resistivity represented by the symbol ρ (low). “Volume resistivity”, also known as “electrical resistivity,” means a measure of how strongly a material blocks current. A low resistivity represents a material that readily allows charge transfer. The SI unit of electrical resistivity is ohm meter (Ωm).
As used herein, the term “thermoplastic polymer” refers to a polymer that becomes liquid when heated and freezes when fully cooled to a very glassy state. Because of this property, thermoplastic polymers can be cast. Thermoplastic polymers have exceeds its intrinsic glass transition temperature T _g, the flexibility exhibits elasticity. Below the second higher melting temperature T _m , most thermoplastics have crystalline regions that alternate with amorphous regions, in which the chains are closer to random coils. Amorphous regions provide elasticity and crystalline regions contribute to strength and stiffness.
As used herein, the term “heat dissipation” refers to the loss of heat that electronic devices and circuits generate over time. This is necessary for these devices to improve reliability and avoid premature failure.
As used herein, the term “heat sink” means a component or assembly that transfers heat generated within a solid material to a fluid medium such as air or liquid. In the simplified form of the one-dimensional form in the x direction, Fourier's law for heat conduction is that when there is a temperature gradient inside the material body, the heat is heated at a rate proportional to the product of the temperature gradient and heat transfer cross section It is transmitted from the region to the low temperature region.
As used herein, the term “temperature gradient” is a difference in temperature, specified as a difference [d] T ₀ −T ₁ or a difference [d] T ₁ −T ₂ .
As used herein, the heat transfer cross section was set to 1.
As used herein, the term “heat sink effect” of a simulated LED housing refers to the ability of the simulated LED housing to transfer heat across certain of the above temperature gradients. The term also refers to the effectiveness of heat dissipation or the heat dissipation capability of these simulated LED housings.
As used herein, the term “overmolding” refers to a process in which a portion of a thermoplastic resin is cast directly onto a second component that includes a metal layer. Overmolding generally means using two separate materials to form one coherent component. There are two types of overmolding, namely the insert method and the “two-shot” method, but the insert overmolding method is a more general method and one material (usually an elastomer) is used. An injection molding process in which a secondary “substrate” material (usually a rigid plastic or object) is “over” molded.
As used herein, “light emitting diode” can be abbreviated as “LED”.
As used herein, “micron meters” can be abbreviated as “micron” or “μm”.
As used herein, “millimeter” can be abbreviated as “mm”.
As used herein, “weight percent” can be abbreviated as “wt%”.
As used herein, “aluminum” can be abbreviated as “Al”.
As used herein, “heat source” can be abbreviated as “HS”.
As used herein, “Watts per meter at Kelvin” can be abbreviated as “W / m, K”.
As used herein, “ohm meter” can be abbreviated as “Ωm”.

Ranges Any range explicitly referred to herein includes its end values unless expressly stated otherwise. References to amounts, concentrations, or other values or parameters as ranges are intended to refer to all ranges formed from any pair of any upper range value and any lower range value as such Specific disclosures whether or not they are disclosed separately. The processes and products described herein are not limited to the specific values disclosed in the scope definitions herein.

Preferred Variations The disclosure herein of any variations relating to materials, methods, steps, values and / or ranges, etc. of the processes, compositions and products described herein is identified as preferred variations. With or without-it is specifically intended to disclose any process and product that encompasses any combination of such materials, methods, steps, values, ranges, and the like. In order to provide clear and sufficient support for the claims, any combination thus disclosed is specifically intended to be a preferred variant of the processes, compositions and products described herein. .

General Matters In this specification, the following light emitting diode (LED) lighting fixtures are described. That is,
a. At least one LED chip;
b. A metal plate on which at least one LED chip is deployed;
c. An LED module in electrical contact with at least one LED chip;
d. A housing in contact with the metal plate, in which the LED module is disposed;
A light emitting diode (LED) lighting fixture comprising:
This housing
i) a resin layer having an inner surface and an outer surface;
ii) a metal layer disposed in a covering manner on at least a portion of the outer surface of the resin layer, the metal layer being in contact with the metal plate;
Including
The resin layer includes an electrically insulating thermoplastic resin composition,
The metal layer includes an aluminum alloy and has a thermal conductivity of at least 20 watts per meter Kelvin (W / m, K) to 40 W / m, K and a thermal emissivity of 0.5 to 0.8. Have
A light emitting diode (LED) lighting fixture.

Also described herein is an LED housing that is deployed within the LED luminaire described herein.
In this case, the LED housing is
i) a resin layer having an inner surface and an outer surface;
ii) a metal layer disposed in a covering manner on at least a portion of the outer surface of the resin layer, the metal layer being in contact with the metal plate;
Including
The resin layer includes an electrically insulating thermoplastic resin composition,
The metal layer includes an aluminum alloy and has a thermal conductivity of at least 20 watts per meter Kelvin (W / m, K) to 40 W / m, K and a thermal emissivity of 0.5 to 0.8. Have.

In any LED luminaire or LED housing described herein, the thermoplastic resin composition is made from polyethylene, polyvinylidene fluoride, polypropylene, nylon, polyester, acrylonitrile butadiene styrene (ABS) polymer and / or copolymers thereof. A thermoplastic resin selected from the group consisting of can be included. In any LED lighting fixture described herein, the thermoplastic resin can be selected from the group consisting of polyester terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, copolyetherester elastomer, and any mixtures thereof; It can have a volume resistivity ρ greater than 10 ⁷ Ωcm. The metal layer of any LED luminaire described herein is an anode aluminum coating that is sufficiently thick to ensure that the coated metal layer has a thermal emissivity of 0.5 to 0.8. Can be included. Further, the metal layer can cover either the full length of the outer surface of the resin layer, or 10 mm, or 15 mm, or 20 mm, or 25 mm, or 30 mm, or 35 mm, or 40 mm, or 50 mm.

In the preferred LED housing described herein, the thermoplastic resin composition is a thermoplastic selected from the group consisting of polyester terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, copolyetherester elastomer, and any mixtures thereof. Resin can be included and can have a volume resistivity ρ greater than 10 ⁷ Ωcm. Also, in the preferred LED housing described herein, the metal layer can include an anode aluminum oxide coating, with a thermal conductivity of 25 W / m, K-32 W / m, K, and 0.6-0. .8 and can cover 20 mm to 25 mm of the outer surface of the resin layer.

  Also described herein is the use of the LED housing described herein in an LED lighting fixture. This results in a temperature measured within 5 millimeters, or 4 millimeters, or 3 millimeters, or 2 millimeters, or 1 millimeter of at least one LED chip below 70 ° C. The temperature measured within 5 millimeters, or 4 millimeters, or 3 millimeters, or 2 millimeters, or 1 millimeter of at least one LED chip is preferably greater than 70 ° C., at least 10 ° C., or 11 ° C., or 12 C, or 15 ° C, or 18 ° C lower.

Also, as used herein, at least one LED chip deployed within any LED luminaire described herein is within 5 millimeters, or 4 millimeters, or 3 millimeters, or 2 millimeters, or 1 millimeter. Maintaining the temperature of less than 70 ° C. or at least 10 ° C., or 11 ° C., or 12 ° C., or 15 ° C., or 18 ° C. below 70 ° C.,
A process including is described.

Also described herein is a process for making LED lighting fixtures. This process
Mounting a metal plate of any LED luminaire described herein, on which at least one LED chip is disposed, to any LED housing described herein. ,
This housing
i) a resin layer having an inner surface and an outer surface;
ii) a metal layer disposed in a covering manner on at least a portion of the outer surface of the resin layer, the metal layer being in contact with the metal plate;
Including
The resin layer includes a thermoplastic resin composition,
The metal layer includes an aluminum alloy and has a thermal conductivity of at least 20 watts per meter Kelvin (W / m, K) to 40 W / m, K and a thermal emissivity of 0.5 to 0.8. Have.

Prior Art LED Lighting Fixture FIG. 1 shows a cross-sectional view of a conventional LED lighting fixture 10 according to the prior art. The LED lighting fixture 10 has an LED chip 100 mounted on a circuit board 102, and the circuit board 102 is subsequently mounted so as to be in direct contact with the metal plate 104. The LED chip 100 functions as a light source, radiates heat, and thus also acts as a heat source.

  The metal plate 104 is in direct contact with and attached to a metal housing 106, usually enclosing the control driver 108 and its cover 110 made of an electrically insulating material. The LED module 150 includes the metal plate 104, the LED chip 100, the control driver 108, and the cover 110.

  In addition to providing a support member for the circuit board 102, the metal plate 104 dissipates the heat radiated by the chip. Electrodes 112 and 114 form the basis for the housing 106 and connect the control driver 108 to an external power source. An insulating resin 116 made of an electrically insulating material separates the housing from each electrode and electrically insulates the electrodes from each other. The electrode 112 functions as a base on which the housing is mounted as shown in the figure, and the electrode 114 insulated from the electrode 112 by the insulating resin 116 can be connected to an external power source. The electrical wiring connecting the various electrical components is not shown.

Structure of LED Lighting Fixture Described herein FIG. 2 illustrates one variation of the LED lighting fixture described and claimed herein. The LED luminaire housing described herein provides better heat transfer from the LED chip or LED module to the surrounding environment compared to prior art LED luminaires. That is, the structure of the housing, together with the conductive properties of the housing material, provides a better heat sink effect that dissipates heat from the LED chip than is known. The improvement in heat transfer is partly the situation in which prior art LED luminaires have an almost completely metal housing, which includes an LED control driver cover as a separate element from the housing. Arising from.

  FIG. 2 shows an LED luminaire 20 having a chip 200 mounted on a circuit board 202. The circuit board 202 is then mounted in direct contact with the metal plate 204. The housing 206 that encloses the control driver 208 includes a resin layer 205 and a metal layer 207, and the metal layer 207 is disposed on the outer surface of the resin layer in a covering manner. Resin layer 205 is made from an electrically insulating thermoplastic composition as described herein and serves as a cover for control driver 208 so that element 110 in the prior art LED luminaire of FIG. Has the same function.

  The metal layer 207 is disposed on the resin layer 205 at the same time as being in contact with the metal plate 204, thereby forming a metal housing portion at the LED chip end of the LED lighting fixture. The metal layer 207 can cover the entire surface or a part of the outer surface of the resin layer 205. FIG. 2 represents a situation in which the metal layer 207 covers the outer surface of the resin layer 205 over a length corresponding to at least a part of the length of the control driver 208 from the metal plate 204. FIG. 5A represents a situation where the metal layer 207 covers the entire outer surface of the resin layer 205. The electrodes 212 and 214 are insulated by an insulating resin 216 that can be made of the same or similar insulating thermoplastic composition as the resin layer 205. Due to this structural difference from the conventional LED luminaire shown in FIG. 1, the LED module 250 of FIG. 2 will substantially match the LED luminaire 20.

  The main structural differences between the LED luminaire according to the prior art shown in FIG. 1 and the LED luminaire described herein and represented in FIG. 2 are (1) a separate control driver cover 110 (FIG. 1). ) Has been removed unnecessarily, (2) the housing 206 (FIG. 2) occupies the cover 110 (in FIG. 1) and has two layers, ie, a resin layer 205 and / or And having a covering metal layer 207 that spreads as a whole. The resin layer 205 can act as both a control driver cover and a housing. The reason is that (1) the resin layer 205 can be injection molded into any suitable geometric shape to form a cavity suitable for enclosing the control driver, and (2) the resin Since layer 205 is composed of an electrically insulating thermoplastic composition, layer 205 can be integrated with insulating resin 216, resulting in a single unit that is lighter in weight than the housing of conventional, primarily metal LED lighting fixtures. This is because an LED housing is created.

How the LED luminaire housing described herein transfers heat from the LED chip The LED luminaire described herein is a two-part configuration of the housing structure of the LED luminaire described herein. In particular, the following characteristics: (1) selection of the material containing the metal layer, (2) the resin layer is completely or partially covered by the metal layer, (3) metal It relies on the layer being in contact with the metal plate that ultimately holds the LED chip and (4) the resin layer is insulative. Therefore, it is the housing structure that includes the contact between the metal layer and the metal plate that facilitates effective heat transfer to dissipate heat from the LED chip as the heat source, while at the same time the material properties of the metal layer and the resin layer. is there.

  In essence, the resin layer acts as a thermal insulation layer at that location closest to the LED module, allowing heat from the LED chip and LED module to flow primarily through the metal plate. Since the metal layer covers the resin layer and is electrically connected to the metal plate, it acts as a heat sink for flowing heat from the metal plate to the surrounding environment. In addition, the thermal conductivity and thermal emissivity of the metal layer help determine the effectiveness of the metal layer as a heat sink.

  Specifically, and with continued reference to FIG. 2, in order to facilitate effective heat transfer through the two-layer housing structure described herein, the metal layer 207 has a sufficiently high thermal conductivity, ie, It should be chosen to have a combined property of thermal conductivity higher than 20 watts per meter Kelvin (W / m, K) and a sufficiently high thermal emissivity, ie ε greater than 0.5. Suitable materials having such composite properties include, but are not limited to magnesium, aluminum, titanium, and the like. Aluminum is lightweight and is commonly referred to as an alumite or aluminum coating and is an IUPAC of the “oxo (oxalumanyloxy) alumane” [International Union of Pure and Applied Chemistry]. Since it can be coated with an anode aluminum oxide film having a name, it is preferable.

  In the housing of the LED luminaire described herein, an aluminum alloy, particularly an ADC12 alloy, which is a commonly available aluminum-silicon-copper alloy, can be used as the metal layer. The ADC12 alloy has a thermal conductivity of about 96 W / m, K, but its thermal emissivity ε is very low, about 0.02 to 0.04.

  ADC 12 has been commonly used as a casting material for LED luminaire housings, but its cost is relatively higher than anodized aluminum and its low thermal emissivity (0.02-0.04). In some cases, heat dissipation in LED lighting fixtures may be insufficient. For this reason, the metal layer can preferably include an anodized aluminum alloy, which can be an anodized ADC12 aluminum alloy. The anodized aluminum alloy layer should have a good balance between thermal emissivity and thermal conductivity. In the case of an anodized coating ADC12 alloy layer, the thermal conductivity of the anodized film is 21 W / m, K and that of the alloy layer is 96 W / m, K, while the thermal emissivity of the whole layer is 0.5-0. 8.

The inventors have surprisingly found that a material having a composite property of 20-40 W / m, K thermal conductivity and 0.5-0.8 thermal emissivity is 96 W / m, K thermal conductivity. And has been found to exhibit the same level of heat dissipation performance as an uncoated aluminum alloy having a thermal emissivity of 0.02 to 0.04. In short, the inventors
Using an anodized aluminum alloy as the metal layer in the LED housing;
Use an electrically insulating thermoplastic resin composition as the resin layer,
Bonding the metal layer to the metal plate; and
Coating the metal layer at least partially on the outer surface of the resin layer;
By combining
It has been found that the heat sink function in the LED housing is enhanced and the temperature of the LED chip is maintained below 70 ° C. Such LED housings extend the life and utility of LED luminaires. The temperature of the LED chips in the LED housing described herein is maintained at least 10 ° C lower than 70 ° C, more preferably at least 12 ° C lower than 70 ° C, and most preferably at least 15 ° C lower than 70 ° C. It is desirable.

Thermal conductivity and thermal emissivity Thermal conductivity is an intrinsic property that conducts heat of a material, and is represented by the symbol k. Physically, a unit temperature difference (difference [Δ [Delta] per unit area, per unit thickness). ] Defined as the rate of heat conduction through the material per T) and measured as watts per meter Kelvin (W / m, K). The reciprocal of thermal conductivity is resistivity, also known as volume resistivity. This is a measure of how strongly a material resists current. This is expressed in low (ρ) and is usually measured in Kelvin meters per watt (K · m / W). Low resistivity indicates a material that easily allows charge transfer (measured in ohm meters [Ωm]).

  The thermal conductivity of the material varies with temperature. In general, the thermal conductivity of a material increases with increasing average temperature. Furthermore, in the metal, the thermal conductivity approximately matches the conductivity according to the Wiedermann-Franz law. The determination of thermal conductivity is mainly done empirically and there are many measurement methods. Each measurement method relies on the thermal properties of the material and the medium temperature. The thermal conductivity of the materials used herein has been reported in the scientific literature.

  The thermal emissivity of a material (denoted as the symbol ε or e) is the relative ability of its surface to emit energy by radiation. It is the ratio of the energy emitted by the material to the energy emitted by the black body at the same temperature. A true blackbody will have ε = 1, whereas any real object will have ε <1. Emissivity is a dimensionless quantity. In general, the darker and blacker the material, the closer to 1 its thermal emissivity. As the reflectivity of the material increases, its emissivity decreases. The emissivity of highly polished silver is about 0.02.

  The emissivity varies with factors such as temperature, emission angle and wavelength. Bright or reflective or metallic surfaces that are exposed to radiation tend to maintain a lower temperature than dark non-metallic surfaces. A typical assumption is that the spectral emissivity of the surface does not change with wavelength, and therefore the emissivity is constant. This is known as the “gray body assumption”.

  Although the emissivity of a material generally varies with its thickness, it is assumed that the emissivity reported in the literature is for an infinitely thick sample. Thus, the emissivity of thinner material samples will be lower than reported in the literature.

  It is easy for the metal layer 207 (FIG. 2) to exhibit the combined properties of sufficient thermal conductivity, ie 20 W / m, K, and sufficient emissivity, ie greater than 0.5. Therefore, it is desirable that the anode aluminum oxide film has an average thickness greater than 10 microns. Generally, when the anodic oxide coating layer thickness is 10 microns or less, the thermal emissivity at the surface of the coated metal is typically less than 0.5. Nevertheless, the coated metal layer has a thermal emissivity greater than 0.5 on its surface and a thermal conductivity higher than 96 W / m, K at its core and higher than 20 W / m, K at its surface. The average thickness of the anodic oxide coating can be made to be 10 microns or less as long as the ratio is exhibited. This ensures that the metal layer functions as an efficient heat sink that transfers the heat generated inside the LED module to the surrounding atmosphere.

Thermoplastic resin in the LED lighting fixture described herein The resin layer 205 of the housing 206 can be made from almost any electrically insulating material. Suitable materials include, but are not limited to: That is, 1) rubber compositions comprising, for example, natural rubber, silicone, isobutylene rubber, styrene butadiene styrene (SBS) polymer and / or liquid rubber carboxyl-terminated butadiene nitrile (CTBN) rubber, 2) for example epoxy, polyurethane, Thermosetting resin composition comprising vulcanized rubber, polyester and / or polyimide, 3) including, for example, polyethylene, polyvinylidene fluoride, polypropylene, nylon, polyester, acrylonitrile butadiene styrene (ABS) polymer and / or copolymers thereof Thermoplastic resins, and 4) mixtures thereof. More specifically, the thermoplastic resin can be selected from the group consisting of polyester terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, copolyetherester elastomer, and mixtures thereof. Commercially available thermoplastic compositions containing polyester or copolyester include Rynite (R), Crastin (R), Sorona (R) and Hytrel (R), all of which are DuPont Available from

  Since the maximum allowable temperature on the outer surface of a typical LED luminaire before the LED chip has deteriorated is typically about 70 ° C., a suitable thermosetting resin composition is a resin layer machine at such high temperatures. Functional groups such as amines, acids, anhydrides, isocyanates, halogens, alcohols and epoxides can be included to increase mechanical strength and stability. Suitable thermoplastic resin compositions can be subjected to a crosslinking process such as radiation or the addition of chemical crosslinking agents.

The electrical insulation of the thermoplastic resin in the resin layer 205 (FIG. 2) supports improving the effectiveness of the heat sink of the housing of the LED luminaire described herein. That is, in order to support the heat sink performance of the metal layer in the housing of the LED lighting fixture described herein, a certain level of insulation performance by the resin layer is required.
This is for the following reason. That is,
(1) The resin layer as an electrical insulator promotes the formation of heat generated by the LED chip inside the LED module;
(2) The metal plate on which the LED chip is placed is a conductive surface that must drain the heat formed in order to maintain the LED chip at a temperature below 70 ° C., and from this metal plate The heat outflow must be made efficient by contact with the heat conducting surface, and
(3) The metal layer directs heat flow from the metal plate to the atmosphere because of its material properties, it is in contact with the metal plate, and it is disposed on the outer surface of the resin layer. ,
This is the situation.

  A typical metric for the electrical insulation of a material is the resistivity or volume resistivity, represented by the symbol ρ, measured in ohm centimeters (Ωcm). Volume resistivity is substantially the inverse of conductivity, which is generally the same as or substantially similar to thermal conductivity.

  Accordingly, the LED luminaire housing described herein is based on (1) the structural novelty of the metal layer that contacts the metal plate and partially or fully covers the resin layer; (2) The resin layer of the housing has a certain volume resistivity (that is, the reciprocal of the thermal conductivity), and at the same time, the metal layer has a certain thermal conductivity on the surface and the core, and a certain constant Based on the novelty of having a thermal emissivity. The structure of the housing, and in particular the metal layer, is coupled with the combined effect of the thermal properties of the housing layer to create a heat sink that mimics the functionality of a housing heat sink made of uncoated aluminum alloy.

In general, for a resin layer (exemplified as 205 in FIG. 2), a thermoplastic resin composition having a volume resistivity ρ greater than 10 ⁷ Ωcm as a volume resistivity measured according to the IEC 60093 standard is preferred. Such a thermoplastic resin composition is one or more of 0 to 20 weight percent selected from the group consisting of lubricants, fluidity modifiers, thermal stabilizers, antioxidants, dyes, pigments, UV stabilizers, and the like. Organic additives can be included provided that they do not negatively affect physical or thermal properties.

  Further, such a thermoplastic resin composition has 0-50 weight percent, or 0.1-50 weight percent, or 1-50 weight percent, or 5-45 weight percent, or 10-40 weight percent of at least one. One filler, which is any material commonly used in thermoplastic resin compositions and can include fillers including reinforcing agents. The at least one filler may or may not have a coating thereon, for example a sizing and / or coating that improves its adhesion to the thermoplastic resin composition. The at least one filler can be organic or inorganic. Suitable fillers include, but are not limited to: That is, minerals such as clay, aorite, talc, wollastonite, mica and calcium carbonate; various forms of glass such as fiber, crushed glass, solid or hollow glass spheres; carbon black or carbon fiber Such as carbon; titanium dioxide; aramid in the form of short fibers, fibrils or fibrids; flame retardants such as antimony oxide, sodium antimonate; and any combination thereof. The at least one filler should not exceed 50 weight percent of the thermoplastic resin composition described herein.

  The thermoplastic resin compositions described herein suitable for use as the resin layer 205 can also serve as a dielectric in any other polymer portion of the LED housing or LED lighting fixture that includes the insulating layer 216. it can.

Fabrication of LED lighting fixtures described herein The LED lighting fixtures described herein produce LED housings by overmolding the metal layer of the housing entirely or partially on top of the resin layer of the housing. Implying to do. The essential point is that the overmolding integrates the metal layer on the surface of the resin layer and electrically connects the housing to the LED metal plate. This LED metal plate is not electrically connected to the LED circuit board. Overmolding can be done by any conventional process, such as extrusion or compression molding, which forms the metal layer by heat and / or pressure and improves adhesion between the metal layer and the resin layer of the housing.

  In order to form an irregular surface for better fixing the resin layer, a silicon primer can be applied to the surface of the metal layer adjacent to the resin layer, or an anodic oxide film treatment can be applied as an alternative method. . U.S. Patent No. 6,057,049 describes an anodic oxide coating treatment for this purpose.

  To contact the metal plate of the LED luminaire with the two-part LED housing described herein, the metal plate is directly on the metal layer of the housing, by mechanical means such as screws, or It can be fixed by adhering means such as caulking.

  The examples further illustrate the effectiveness of the overmolded metal layer-resin layer structure of the LED housing described herein to dissipate heat from the LED heat source. This was done by simulating the housing described herein and measuring the dissipation of heat at various distances from the simulated heat source.

LED simulation test To measure the heat transfer through the overmolded housing described herein, an LED simulation test was conducted. The test was performed using a rectangular test piece having dimensions of 6 mm width × 50 mm length × 2 mm thickness. The specimen is molded from the resin described herein and is coated with a 0.3 mm thick metal as disclosed in Table 1 to simulate the overmolded housing described herein. A rectangular test piece and a simulated LED heat source mounted on the test piece are provided with a specific type of LED module, i.e., an LED chip, at one end so that heat from the chip is transferred to the LED luminaire. Approximate an LED module that occurs from one end.

The LED chip as a heat source was simulated by attaching a characteristic element (Test Element Grid: TEG) chip available from Kyocera Corporation to one end of the test piece. Temperature sensors were attached at several different distances from the TEG chip. The distance T ₀ is directly below the TEG chip, the distance T ₁ is 20 mm away from the TEG chip, the distance T ₂ is 35 mm away from the TEG chip, and 15 mm away from T ₁ . By measuring the temperature at different distances from the heat source, it was expected to show the effectiveness of the simulated housing to dissipate heat from the heat source, ie its ability to act as a heat sink.

Materials for LED simulation test Heat source: TEG chip AD-A6086A7 available from Kyocera Corporation;
The voltage and current values for the heat source were set to 3.99 V and 100 mA, respectively, to control the temperature of the heat source itself to 80.0 ° C .;
Thermal sheet: Silicone thermal sheet HF-543 available from Sanhatoya Corporation;
Temperature sensor: ST-23K-100-TS1.5 available from Adachi Corporation;
Aluminum alloy: ADC12 (aluminum-silicon-copper-based aluminum alloy) available from Daiwa Alloy Manufacturing Co., Ltd .;
Thermoplastic composition:
(1) Crastin® SK605NC010 Lot. From DuPont, Wilmington, Delaware, USA 30% glass reinforced polybutylene terephthalate [PBT] commercially available as AFCKH16101;
(2) Thermal conductivity [TC] PBT = 21 weight percent PBT; 12 weight percent flame retardant; 18 weight percent titanium dioxide [TiO ₂ ]; 48 weight percent magnesium oxide [MgO]; Fillers / additives. TC-PBT has a 15 W / m, K core thermal conductivity to observe differences in heat transfer of metal-resin housings using 30% glass reinforced PBT versus PBT with low filler concentration It is what was used for.

Rectangular Specimen Fabrication The polymer compositions of Table 1 were prepared by kneading in a 32 mm Werner and Pfleiderer twin screw extruder. Most of the ingredients were mixed together and charged to the back of the extruder (barrel 1). However, the thermally conductive filler and fibrous filler were fed side by side to barrel 5 (of 10 barrels). The barrel temperature was set at about 250 ° C. for a polybutylene polymer composition having a melt temperature of about 270 ° C.

  The polybutylene polymer composition was injection molded into rectangular test pieces with a mold temperature of about 100 ° C. Each specimen has a metal coating layer of different length as reported in Table 1. By changing the length of the metal covering the resin, the heat sink characteristics of the test piece are changed.

  3-7 show five different configurations of simulated LED lighting fixtures 30, 40, 50, 60 and 70, and corresponding test strips 31, 41, 51, 61 and 71, respectively. The effectiveness in heat transfer was tested and the results are listed in Table 1.

  FIG. 3A shows a simulated LED luminaire 30 having a housing 306. The housing 306 includes only a metal layer 307 made of an ADC12 aluminum alloy and lacks a resin layer. FIG. 3B shows a test piece 31 that simulates the LED lighting apparatus 30. The test piece 31 represents a single metal layer 307 having a length of 50 mm, and represents Comparative Example C1 in Table 1.

  FIG. 4A shows a simulated LED luminaire 40 having a housing 406. The housing 406 includes only a resin layer 405 made of either 30% glass reinforced PBT or TC-PBT and lacks a metal layer. FIG. 4B shows a test piece 41 that simulates the LED lighting apparatus 40. The test piece 41 shows a resin layer 407 having a length of 50 mm, and represents Comparative Examples C2 and C3.

FIG. 5A shows a simulated LED luminaire 50 having a housing 506 composed of a resin layer 505 that is completely covered by a metal layer 507. FIG. 5B shows a test piece 51 that simulates the LED lighting apparatus 50. By including a resin layer completely covered by a metal layer having a length L _{5 of} 50 mm, the test piece 51 represents Examples E1 and E4 in Table 1.

FIG. 6A shows a simulated LED luminaire 60 having a housing 606 consisting of a resin layer 605 partially covered by a metal layer 607. FIG. 6B shows a test piece 61 that simulates the LED lighting apparatus 60, in which the metal layer having a length L _{6 of} 25 mm partially covers the resin layer. Test piece 61 represents Examples E2 and E5 in Table 1.

FIG. 7A shows a simulated LED luminaire having a housing 706 composed of a resin layer 705 covered by a metal layer 707. FIG. 6B shows a test piece 71 that simulates the LED lighting apparatus 70. By including a resin layer partially covered by a metal layer having a length L _{7 of} 20 mm, the test piece 71 represents Examples E3 and E6 in Table 1.

  FIG. 8 shows a plan perspective view of a rectangular test piece used as Comparative Example 2 or 3 consisting only of a resin layer, and FIG. 9 is used in Examples E1 and E4 having a resin layer completely covered with a metal layer. The top perspective view of the rectangular test piece which was included is shown.

Measurement of temperature at different distances from the heat source In the LED simulation test, T ₀ is the temperature measured at the heat source, thus approximating the temperature of the LED chip in the LED luminaire or a temperature very close to it. In general, for LED luminaires used (at room temperature), T ₀ must be less than 70 ° C. to avoid thermal damage to the LED chip. As described above, T ₁ is the temperature at a position 20 mm from the heat source, and T ₂ is the temperature at a position 35 mm from the heat source. For this reason, when the temperatures T ₀ , T ₁ and T ₂ are measured at different positions from the heat source, the amount of temperature drop between the measured distances is given by a simple subtraction.

Measurement of Thermal Emissivity and Thermal Conductivity The measured value of thermal emissivity was obtained from the center of the specimen of FIGS. 8 and 9, which correspond to Examples 1-3 and 4-6 in Table 1, respectively. The measurement of thermal emissivity was carried out by Nippon Sheet Glass Techno Research Co., Ltd. In this measurement, the ratio of the integrated radiant intensity (with respect to the wavelength range of 4 to 20 micrometers) of the sample and the integrated intensity of the complete black body was measured by infrared using a JIR-5500 instrument available from JEOL Ltd. Measured using spectroscopy.

The thermal conductivity of the same specimen was also measured at the center of the specimen by the Laser Flash Method (ASTM E1461). The thermal conductivity at T ° C. can be calculated from the following equation (1).
λ (T) = a (T) × Cp (T) × ρ (T) (1)
However,
λ (T) is the thermal conductivity at T ° C.
a (T) is the thermal diffusivity at T ° C. measured using LFA447 from NETZSCH,
Cp (T) is the specific heat at T ° C. measured using Q100 of TA Instruments,
ρ (T) is the density at T ° C. measured using SD-200L of Alpha Mirage Co., Ltd.
It is.

ＬＥＤ模擬試験条件：
周囲温度：２５．７℃
熱源：ＴＥＧチップＡＤ−Ａ６０８６Ａ７（京セラ（株）から入手可能）；熱源に対する電圧値および電流値は、熱源自体の温度を８０．０℃に制御するためにそれぞれ３．９９ Ｖおよび１００ｍＡに設定した。
熱シート：シリコーン熱シートＨＦ−５４３（サンハトヤ（株）から入手可能）
温度センサー：ＳＴ−２３Ｋ−１００−ＴＳ１．５（安達（株）から入手可能）
アルマイト被膜処理アルミニウム：Ａｌｐｌｕｓ（商標）（コロナ工業（株）から入手可能）、厚さ；０．０１５ｍｍ（アルマイト）＋０．３ｍｍアルミニウム
樹脂：３０％ガラス強化ＰＢＴ（ｇｒＰＢＴ）：Ｃｒａｓｔｉｎ（商標）ＳＫ６０５ＮＣ（ＤｕＰｏｎｔ）
ＴＣ−ＰＢＴ：ＰＢＴ（２１重量％）／ＦＲ（１２％）／ＴｉＯ２（１８％）／ＭｇＯ（４８％）／その他（１％）

LED simulation test conditions:
Ambient temperature: 25.7 ° C
Heat source: TEG chip AD-A6086A7 (available from Kyocera Corporation); voltage and current values for the heat source were set to 3.99 V and 100 mA, respectively, to control the temperature of the heat source itself to 80.0 ° C. .
Thermal sheet: Silicone thermal sheet HF-543 (available from Sanhatoya Co., Ltd.)
Temperature sensor: ST-23K-100-TS1.5 (available from Adachi Corp.)
Anodized aluminum: Alplus ™ (available from Corona Kogyo Co., Ltd.), thickness; 0.015 mm (alumite) + 0.3 mm Aluminum resin: 30% glass reinforced PBT (grPBT): Crastin ™ SK605NC ( DuPont)
TC-PBT: PBT (21 wt%) / FR (12%) / TiO2 (18%) / MgO (48%) / Other (1%)

Results This section is divided into two parts. The first part is the temperature measurement at an individual distance from the heat source, specifically T ₀ (in / on the heat source [“HS”]) of the simulated LED luminaire housing illustrated in Table 1. Temperature measurement results at T ₁ (15 mm from HS) and T ₂ (20 mm from HS) are presented. Section 1 also describes the effect of the resin layer composition on temperature changes at these distances from the heat source.

Section 2 describes the difference between T ₀ and T ₁ in the individual lengths of the metal layers of the simulated LED luminaire housing illustrated in Table 1—50 mm, 25 mm or 20 mm—and T ₁ and T _2. The difference between them will be explained. This section focuses on the heat sink effect of the metal layer due to the length of the metal layer and the combination of its thermal conductivity and thermal emissivity.

Results of T ₀ in the results Table 1 T ₀ (in the heat source) has been measured in the heat source of the specimen, the expected temperature of the Case / Comparative Example manner LED luminaire housing in the LED chip position or bottom thereof Simulate. It is important to compare the result of T ₀ with 70 ° C., which is the internal temperature of the LED module, where the function of the LED chip begins to decline.

Comparative Example 1 [CE1] simulates an LED lighting apparatus having a housing with only an aluminum metal layer having a thickness of 2 mm, and T ₀ thereof was 47.9 ° C. The T ₀ of CE2 simulating an LED lighting device having a housing with only a 30% glass-reinforced PBT resin layer was 83.9 ° C. Since 83.9 ° C. is higher than 70 ° C., it is expected that an LED luminaire housing with only a 30% glass reinforced PBT resin layer will actually cause LED malfunction. The T ₀ of CE3 simulating an LED lighting apparatus having a housing with only a TC-PBT resin layer was 56.2 ° C.

Examples 1-3 simulate an LED luminaire with a housing having a 30% glass reinforced PBT resin layer and anodized aluminum metal layers of different lengths. T ₀ was 51.0 ° C., 51.2 ° C. and 51.4 ° C., respectively. The average variation in T ₀ for the different lengths of the metal layer—50 mm, 25 mm and 20 mm respectively—was only 0.4%.

Similarly, T ₀ of Examples 4 to 6 simulating LED lighting fixtures having a housing including a TC-PBT resin layer and alumite-coated aluminum metal layers having different lengths are 50.9 ° C. and 50. 9 ° C and 51.1 ° C. The average variation in T ₀ for different lengths of the metal layer—50 mm, 25 mm and 20 mm respectively—was only 0.1%.

Thus, Table 1 shows that the heat dissipation at or just below the LED chip does not depend on the different lengths of the housing metal layer. More importantly, the measured T ₀ values of all Examples E1 to E6 are at least 17 ° C. lower than the LED chip malfunction temperature limit of 70 ° C. Thus, all six examples suggest that the LED luminaire housing described herein appears to facilitate and sustain the operation of the LED luminaire.

Furthermore, Table 1 shows that the average T ₀ for all six examples is only 6.7% higher than the CE 1 T ₀ representing a housing made of an Al alloy with a thermal emissivity of 0.02. It also shows. The heat sink effect of the Al alloy housing results from the combined effect of aluminum thermal conductivity and thermal emissivity. The thermal conductivity of 96 W / m, K of Al alloy (ADC-12) is much higher than that of alumite. Nevertheless, E1-E3 and E4-E6 are almost equivalent to that of Al alloy (ADC-12) because of the combined effect of thermal conductivity and thermal emissivity of the two-part structure of the simulated housing. The heat sink performance of was shown.

T ₀ of E1~E3 is slightly higher than T ₀ of E4~E6. This is because slightly good heat sink performance can be obtained using 30% GR-PBT including a metal layer of arbitrary length, but by using TC-PBT as an alternative to this 30% GR-PBT, Definitely suggests that very good results are obtained.

  Table 1 shows that the heat dissipation of the two-part housing described herein, which is simulated by the example, is close to that of an aluminum alloy housing, revealing LED chip failure from extreme heat exposure. It clearly states that it will prevent.

T ₁ of the result (20mm from HS)
Results of T ₁ in Table 1 is the temperature measured at the position of 15mm from the heat source of the specimen. CE1 T ₁ is 40.6 ° C. of (2mm of Al alloy layer only), T ₁ of CE2 (30% GR-PBT resin layer only) 25.8 ° C., T ₁ of the CE3 (TC-PBT resin layer only) Was 39.3 ° C. These data indicate that only the 30% glass reinforced PBT resin layer cannot transfer heat due to its low thermal conductivity.

T ₁ of Examples 1 to 3 (30% GR-PBT resin layer and anodized aluminum metal layer having different lengths) was 43.7 ° C., 43.5 ° C., and 26.5 ° C., respectively. It was. The variation in T ₁ between E1 (50 mm metal layer) and E2 (25 mm metal layer) was only 0.2%. However, the average variation in T ₁ between E1 / E2 (50 mm, 25 mm) and E3 (20 mm metal layer) collectively was surprisingly 39%. The low T _{1 in} the case of E3 is due to the fact that the temperature sensor for E3 was not mounted on the alumite layer as in the case of E1 and E2, but on the 30% glass reinforced PBT resin layer. .

T ₁ of Examples 4 to 6 (TC-PBT resin layer and anodized aluminum metal layer having different lengths) were 43.5 ° C., 43.6 ° C., and 41.4 ° C., respectively. The variation in T ₁ between E4 (50 mm metal layer) and E5 (25 mm metal layer) was only 0.1%. However, the average variation in T ₁ between E4-E5 (50 mm, 25 mm) and E6 (20 mm metal layer) collectively was 5%.

Comparing the T ₁ of the T ₁ and E4~E6 of E1 to E3, the thermal conductivity of the TC-PBT is better than the thermal conductivity of the 30% GR-PBT, between T ₀ and T ₁ It shows that the overall temperature equalization is much better in the case of the TC-PBT examples (4-6). Furthermore, the difference in heat dissipation of different metal lengths in the case of the TC-PBT examples (4-6) is not substantial, which is the length of the metal layer when using TC-PBT resin. At any rate, it was expected that heat dissipation at 20 mm from the heat source would have almost equal effect.

T ₂ of the result (35mm from HS)
The result of T ₂ in Table 1 is its temperature measured at a position 35 mm from the heat source, which is 35 mm away from the heat source of the comparative LED luminaire housing and the LED luminaire housing described herein. Simulate expected temperature at different locations.

Table 1 shows that T _{2 of} Comparative Example 1 simulating an LED lighting apparatus having a housing composed of only an aluminum alloy layer having a thickness of 2 mm is 37.9 ° C. T _{1 of} Comparative Example 2 that simulates an LED lighting apparatus having a housing composed only of a 30% glass-reinforced PBT resin layer has a T ₁ of 25.7 ° C., and the LED illumination includes a housing composed only of a TC-PBT resin layer. T _{1 of} Comparative Example 3 simulating the instrument was 35.4 ° C. These data are consistent in that they indicate that a 30% glass reinforced PBT resin layer without a metal layer cannot transfer heat from T ₁ to T ₂ .

T ₂ of Examples 1 to 3 (30% GR-PBT resin layer and anodized aluminum metal layer having different lengths) was 40.2 ° C., 25.7 ° C., and 25.7 ° C., respectively. It was. That is, there was no variation in T ₂ between E2 (with a 25 mm metal layer) and E3 (with a 20 mm metal layer). However, the variation in T ₂ between E1 (50 mm) and collectively E2-E3 (20 mm-35 mm) was about 36%. Thus, Table 1 shows that the heat dissipation in LED luminaires with a 30% glass reinforced PBT resin layer is lower than 1/3 when equipped with either a 25 mm or 20 mm metal layer.

T ₂ in Examples 4 to 6 (TC-PBT resin layer and anodized aluminum metal layer having different lengths) was 40.2 ° C., 38.6 ° C., and 37.6 ° C., respectively. It was. The average variation of T ₂ in these three examples was about 2.4%.

Results on the difference between T ₀ and T ₁ (ΔT ₀ -T ₁ ) In this discussion, a lower ΔT ₀ -T ₁ indicates better heat dissipation performance. That is, the temperature difference between T ₀ and T ₁ indicates the effectiveness of the heat sink of different length metal layers on top of different thermoplastic layers at a position 20 mm from the heat source.

ΔT ₀ −T ₁ is a temperature difference between T ₀ (observed at the heat source) and T ₁ (observed at a position 20 mm from HS), and is obtained by subtracting T ₁ from T ₀ . Table 1 shows that the values of ΔT ₀ -T ₁ for CE1, CE2 and CE3 were 7.3 ° C., 58.1 ° C. and 16.9 ° C. CE1, CE2, and CE3 each simulate an LED luminaire housing with only one layer of either a 2 mm thick aluminum alloy metal layer, or a 30% glass reinforced PBT resin layer, or a TC-PBT resin layer. there were.

Since the C1-C3 simulated LED housing has either a heat radiating layer or a heat conducting layer, the decrease in the CE1-CE3 LED luminaire housing temperature at T ₀ and T ₁ is a combination of a heat radiating material and a heat conducting material. It can never be due to effects. Therefore, ΔT ₀ -T _{1 of} CE1 to CE3 indicates only the heat sink effect depending on the distance from the heat source, that is, only the heat dissipation. Ultimately, this heat dissipation was related to the intrinsic thermal emissivity or intrinsic thermal conductivity of the LED luminaire housing layers of CE1, CE2 and CE3.

Table 1 shows that ΔT ₀ -T _{1 in} the case of the example using the glass reinforced PBT resin layer is 7.3 ° C. for E1 (50 mm metal layer), 7.8 ° C. for E2 (25 mm metal layer), and E3. In the case of the example using the TC-PBT resin layer, ΔT ₀ -T ₁ is 7.4 ° C. in the case of E4 (50 mm metal layer) and E5 (25 mm metal layer). ) In the case of 7.3) and 9.7 ° C. in the case of E6 (20 mm metal layer).

The important point is that the measured values of ΔT ₀ -T ₁ in the case of CE1, E1, E4 (50 mm metal layer), and E2, E5 (25 mm metal layer) are substantially similar. This is the point that only 7% is changed at most. Therefore, E1, E4 (50 mm alumite coating treated Al layer), E2 and E5 (25 mm alumite coating treated Al layer) are an LED luminaire housing composed only of a 3 mm thick Al alloy layer, and heat dissipation. Have equal effectiveness. This effect is explained by the following consideration.

  The thermal conductivity of the CE1 Al alloy is very high, 96, while the thermal emissivity of the Al alloy is very low, only 0.02. CE1 may conduct heat at an equal and efficient rate over the entire length of the luminaire housing.

  The thermal conductivity of the anodized aluminum layers E1 to E6 is medium and 30, whereas the thermal emissivity of the resin layer is very high, 0.91 for E1 to E3, and 0 for E4 to E6. 92. The metal layers of all examples had essentially the same thermal conductivity and thermal emissivity. They would be expected to dissipate heat at the same rate over the entire length of the luminaire housing. This dissipation rate will be different from the CE1 housing with only a 3 mm thick Al alloy layer.

However, as shown in Table 1, E1, E2, E4 and E5 conduct heat at substantially the same rate as CE1 at a position 20 mm from the heat source. E1, E2, E4 and E5 simulate an LED luminaire housing with a metal layer of either 50 mm or 25 mm. Achieving the same heat dissipation rate as CE1 has at least the following terms:
1) the ratio of thermal conductivity and thermal emissivity of the metal layer, and
2) 50 mm or 25 mm length of the metal layer,
Depended on. That is, Table 1 shows that the simulated housing of the LED housing described herein exhibited a heat sink effect similar to −T _{1 at} a position 20 mm from the heat source.

In the case of E3 and E6 (20 mm metal layer), ΔT ₀ -T ₁ was 24.9 ° C. and 9.7 ° C., respectively. The variation in ΔT ₀ -T ₁ between E3 and C1 is −241% and that between E6 and C1 is −33%. Negative values reflect that E3 and E6 have greater heat dissipation than CE1 at 20 mm from the heat source. The metal layers of E3 and E6 had the same thermal conductivity and thermal emissivity as in E1, E2, E4 and E5. Thus, the primary factor that resulted in a much higher heat sink effectiveness for E3 and E6 was a 20 mm metal layer.

In summary, Table 1 shows that a 20 mm metal layer in the LED luminaire housing described herein is far more effective at either 20 mm from the heat source than a 25 mm or 50 mm metal layer. Indicates that the effect has been achieved. However, it is emphasized that a 25 mm or 50 mm coated metal layer in the LED luminaire housing described herein was as effective in heat dissipation as a 3 mm thick Al alloy all metal LED luminaire housing. I have to keep it. Therefore, the ΔT ₀ -T ₁ result is a commercial in that the LED luminaire housing described herein dissipates heat at least as much as and at a lower cost than a 3 mm thick Al alloy. It shows that it was able to aim for profit.

Results on the difference between T ₁ and T ₂ (ΔT ₁ -T ₂ ) In this discussion, a lower ΔT ₁ -T ₂ indicates better heat dissipation performance. That is, the temperature difference between T ₁ and T ₂ is a measure of the effectiveness of a heat sink of different lengths of metal layers at a location 35 mm from the heat source.

ΔT ₁ −T ₂ is the temperature difference between T ₁ (observed at 20 mm from HS) and T ₂ (observed at 35 mm from HS), subtracting T ₂ from T ₁ can get. Table 1 shows that ΔT ₁ -T ₂ values for C1, C2 and C3 were 2.7 ° C., 0.1 ° C. and 3.9 ° C. Specifically, C1, C2 and C3 are each composed of only one layer of either a 2 mm thick aluminum alloy metal layer, or a 30% glass reinforced PBT resin layer, or a TC-PBT resin layer. It simulated a luminaire housing.

Table 1 shows that ΔT ₁ -T _{2 in} the case of the glass reinforced PBT resin layer example is 3.5 ° C. for E1 (50 mm metal layer), 17.7 ° C. for E2 (25 mm metal layer), and E3 In the case of the example using the TC-PBT resin layer, ΔT ₁ -T ₂ measured values are 3.3 ° C. and E5 (25 mm in the case of E4 (50 mm metal layer). In the case of (metal layer), it was 5 ° C., and in the case of E6 (20 mm metal layer), it was 3.8 ° C.

E1-E6 all have substantially the same ratio of the thermal conductivity of the metal layer to the thermal emissivity of the resin layer. The variation in ΔT ₁ -T ₂ between E1 and E4 (50 mm metal layer) was about 6%. Therefore, the 50 mm metal layer above the 30% glass reinforced PBT resin layer achieved a somewhat better heat sink effect than the same metal layer above the TC-PBT resin layer at a position 35 mm from the heat source.

The variation in ΔT ₁ -T ₂ between E2 and E5 (25 mm metal layer) was about 72% (obtained from 17.7-5 = 12.7 / 17.7). Therefore, the 25 mm metal layer above the 30% glass reinforced PBT resin layer realized 72% better heat sink effect than the same metal layer above the TC-PBT resin layer at a position 35 mm from the heat source.

The variation in ΔT ₁ -T between E3 and E6 (20 mm metal layer) was -375% (obtained from 0.8-3.8 = -3.0 / 0.8). Therefore, the 20 mm metal layer above the TC-PBT layer realized a heat sink effect almost 4 times better than the same metal layer above the glass reinforced PBT resin layer at a position 35 mm from the heat source.

  These results confirmed the initial conclusion, that is, the most efficient LED luminaire housing structure for heat dissipation has a metal layer length of either 20 mm or 25 mm. . Furthermore, at a position 35 mm from the heat source, the longer metal layer produced a better heat sink effect in the upper part of the glass reinforced PBT resin layer, whereas the 20 mm metal layer was more in the upper part of the TC-PBT layer. It produced a good heat sink effect.

  Accordingly, by focusing on either different resin compositions or different lengths of the metal layer, the same or similar conclusions are drawn for the LED housings simulated in Examples E1-E6. Either one of the resin layers may be more efficient depending on the different lengths of the metal layer, but either the resin layer either fully or partially covered by an alumite-coated Al metal layer Is used to simulate an LED luminaire housing that dissipates heat at the heat source, or at a location 20 mm from HS, or at a location 35 mm from HS, in which case the simulated LED luminaire has an excess of heat. Exposure does not cause dysfunction.

Claims (13)

a. At least one LED chip;
b. A metal plate on which the at least one LED chip is disposed;
c. An LED module in electrical contact with the at least one LED chip;
d. A housing in contact with the metal plate, the housing in which the LED module is disposed;
A light emitting diode (LED) lighting fixture comprising:
The housing is
i) a resin layer having an inner surface and an outer surface;
ii) a metal layer disposed in a covering manner on at least a portion of the outer surface of the resin layer, the metal layer being in contact with the metal plate;
Including
The resin layer includes an electrically insulating thermoplastic resin composition, and
The metal layer includes an aluminum alloy and has a thermal conductivity of at least 20 watts per meter Kelvin (W / m, K) to 40 W / m, K, and a thermal emissivity of 0.5 to 0.8. Having
Light emitting diode (LED) lighting fixture.   The thermoplastic resin composition comprises a thermoplastic resin selected from the group consisting of polyethylene, polyvinylidene fluoride, polypropylene, nylon, polyester, acrylonitrile butadiene styrene (ABS) polymer and / or copolymers thereof. LED lighting fixture according to.   The LED luminaire of claim 2, wherein the thermoplastic resin is selected from the group consisting of polyester terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, copolyetherester elastomer, and any mixture thereof. The LED lighting fixture according to any one of claims 1 to 3, wherein the thermoplastic resin composition has a volume resistivity ρ greater than 10 ⁷ Ωcm.   5. The anode of claim 1, wherein the metal layer comprises an anode aluminum coating having an average thickness sufficient to ensure that the coated metal layer has a thermal emissivity of 0.5 to 0.8. The LED lighting device according to claim 1.   The LED lighting fixture according to any one of claims 1 to 5, wherein the metal layer covers the entire length of the outer surface of the resin layer.   The LED lighting apparatus according to claim 1, wherein the metal layer covers 20 to 25 mm of the outer surface of the resin layer. An LED housing that is deployed inside an LED luminaire,
The LED lighting fixture is
At least one LED chip;
A metal plate on which the at least one LED chip is disposed;
An LED module in electrical contact with the at least one LED chip;
Including
The housing is
i) a resin layer having an inner surface and an outer surface;
ii) a metal layer disposed in a covering manner on at least a portion of the outer surface of the resin layer, the metal layer being in contact with the metal plate;
Including
The resin layer includes an electrically insulating thermoplastic resin composition, and
The metal layer includes an aluminum alloy and has a thermal conductivity of at least 20 watts per meter Kelvin (W / m, K) to 36 W / m, K, and a thermal emissivity of 0.5 to 0.8. Having
LED housing. The thermoplastic resin composition is
Comprising a thermoplastic resin selected from the group consisting of polyester terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, copolyetherester elastomer and any mixture thereof;
Having a volume resistivity ρ greater than 10 ⁷ Ωcm, and
The metal layer is
An anode aluminum oxide coating,
Having a thermal conductivity of 25 W / m, K to 32 W / m, K and a thermal emissivity of 0.6 to 0.8;
Covering 20 to 25 mm of the outer surface of the resin layer;
The LED housing according to claim 8.   Use of an LED housing in an LED luminaire according to claim 8 or 9, wherein the temperature measured within 3mm of the at least one LED chip is less than 70C.   Use according to claim 10, wherein the temperature measured within 3 mm of the at least one LED chip is at least 12 ° C lower than 70 ° C. Maintaining a temperature within 3 mm of at least one LED chip deployed in the LED luminaire below 70 ° C .;
A method comprising:
The LED lighting fixture is
a. At least one LED chip;
b. A metal plate on which the at least one LED chip is disposed;
c. An LED module in electrical contact with the at least one LED chip;
d. A housing in contact with the metal plate, the housing in which the LED module is disposed;
Including
The housing is
i) a resin layer having an inner surface and an outer surface;
ii) a metal layer disposed in a covering manner on at least a portion of the outer surface of the resin layer, the metal layer being in contact with the metal plate;
Including
The resin layer includes an electrically insulating thermoplastic resin composition, and
The metal layer includes an aluminum alloy and has a thermal conductivity of at least 20 watts per meter Kelvin (W / m, K) to 36 W / m, K, and a thermal emissivity of 0.5 to 0.8. Having
Method. Securing a metal plate of an LED luminaire on which at least one LED chip is deployed to a housing for the LED luminaire;
A method of manufacturing an LED lighting apparatus including:
The housing is
i) a resin layer having an inner surface and an outer surface;
ii) a metal layer disposed in a covering manner on at least a portion of the outer surface of the resin layer, the metal layer being in contact with the metal plate;
Including
The resin layer includes an electrically insulating thermoplastic resin composition, and
The metal layer includes an aluminum alloy and has a thermal conductivity of at least 20 watts per meter Kelvin (W / m, K) to 36 W / m, K, and a thermal emissivity of 0.5 to 0.8. Having
Production method.

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