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    • 专利摘要:
    THERMALLY TRANSPARENT CONDUCTIVE POLYMER COMPOUNDS FOR THERMAL LIGHT SOURCE MANAGEMENT. The invention relates to a light emitting device. The light emitting apparatus includes a transmissive light envelope, a light source being in thermal communication with a heat sink; and a plurality of heat fins in thermal communication with the heat sink and extending in a direction such that the heat fins are adjacent to the light transmissive envelope. The plurality of heat fins comprises a polymer compound filled with carbon nanotubes.
    公开号:BR112012017088B1
    申请号:R112012017088-0
    申请日:2011-01-11
    公开日:2021-01-19
    发明作者:Ashfaqul Islam Chowdhury；Gary Robert Allen
    申请人:GE Lighting Solutions, LLC；
    IPC主号:
    专利说明:

    [001] This application claims the benefit of U.S. Provisional Application Number 61 / 294,231 filed on January 12, 2010. U.S. Provisional Application Number 61 / 294,231 filed on January 12, 2010 is hereby incorporated by reference in its entirety. BACKGROUND
    [002] The present exemplary modality refers to lighting devices, and specifically to lighting devices that include light emitting diodes (LED). However, it must be appreciated that the exemplary modality present is also receptive to other similar applications. BRIEF DESCRIPTION
    [003] Incandescent and halogen lamps are conventionally used with omnidirectional, non-directional and directional light sources, especially in residential, hospital and retail lighting applications. Omnidirectional lamps are intended to provide a substantially uniform intensity distribution versus the angle in the distant field, greater than 1 meter away from the lamp, and find several applications such as desk lamps, table lamps, decorative lamps, chandeliers, lighting equipment. ceiling, and other applications where uniform light distribution in all directions is desired.
    [004] Recently, there has been a market demand for higher energy efficiency light sources than conventional light sources such as incandescent and halogen lamps. Compact fluorescent lamps (CFL) have gradually gained market share over the past ten years based on their high efficiency (~ 50-60 LPW) and long life (~ 5-10 kHr) compared to incandescent and light bulbs. halogen (~ 10-25 LPW, 1-5 kHr), despite its relatively worse color quality, heating time, brightness variation and acquisition cost. Solid-state light sources such as LEDs are more recently evolving into the primary choice for high-efficiency omnidirectional and directional light sources while both LEDs and OLEDs are being developed as sources of choice for non-light sources. directional. The light source for high efficiency non-directional lighting is application dependent and may vary.
    [005] With reference to Figure 1, a coordinate system is described which is used here to describe the spatial distribution of illumination generated by an incandescent lamp or, more generally, by a lamp designed to produce omnidirectional illumination. The coordinate system is of the spherical coordinate system type, and is described in Figure 1 with reference to an incandescent lamp L. For the purpose of describing the distribution of distant field lighting, the lamp L can be considered to be located at the point L0, which can, for example, match the location of the incandescent filament. Adapting the spherical coordinate notation conventionally employed in the geographic technique, a lighting direction can be described by an elevation or latitude coordinate θ and an azimuth or longitude coordinate Φ- However, in a deviation from the geographical technique convention, the elevation or latitude coordinate θ used here employs a range [0 °, 180 °] where: θ = 0 ° corresponds to "geographic north" or "N". This is convenient because it allows the illumination along the direction θ = 0 ° to correspond to the light directed forward. The north direction, that is, the direction θ = 0 °, is also referred to here as the optical geometric axis. Using this notation, θ = 180 ° corresponds to "geographic south" or "S" or, in the context of lighting, to the light directed backwards. The elevation or latitude θ = 90 ° corresponds to the "geographic equator" or, in the context of lighting, to the light directed laterally.
    [006] With continued reference to Figure 1, for any given elevation or latitude θo an azimuth or longitude coordinate Φ can also be defined, which is everywhere orthogonal to the elevation or latitude θo. The azimuth or longitude coordinate Φ has a range of [0 °, 360 °], according to the geographical notation.
    [007] It will be appreciated that precisely in the north or south, that is, at θ = 0 ° or θ = 180 ° (in other words, along the optical geometric axis), the azimuth or longitude coordinate has no meaning, or, perhaps more precisely, can be considered degenerate. Another special coordinate is θ = 90 ° which defines the plane transverse to the optical geometric axis which contains the light source (or more precisely, it contains the nominal position of the light source for distant field calculations, for example, the point L0 in the illustrative example shown in Figure 1).
    [008] In practice, obtaining a uniform light intensity across the entire longitudinal amplitude Φ = [0 °, 360 °] is typically not difficult, because it is straightforward to build a light source with rotational symmetry around the optical geometric axis ( that is, around the geometric axis θ = 0 °). For example, the incandescent lamp L appropriately employs an incandescent filament located in the center of coordinates L0 which can be designed to emit a substantially omnidirectional light, thus providing a uniform illumination distribution corresponding to the azimuth θ for any latitude.
    [009] However, obtaining optimal omnidirectional lighting in relation to the elevation or latitude coordinate θ is generally not practical. For example, the L lamp is built to mount on a standard "Edison base" lamp device, and for this purpose the incandescent lamp L includes a threaded Edison EB base, which can be, for example, an E25 lamp base , E26, or E27 where the number denotes the outside diameter of the threads on the EB base, in millimeters. The Edison EB base (or, more generally, any energy input system located "areas" of the light source) is on the optical geometric axis "behind the position of the L0 light source, and thereby blocks back lighting ( that is, it blocks the illumination along the southern latitude, that is, along θ = 180 °), and so the incandescent lamp L cannot provide an ideal omnidirectional light in relation to the latitude coordinate θ.
    [0010] Nonetheless, commercial incandescent lamps are readily constructed which provide illumination across the latitude range θ = [0 °, 135 °] which is uniform within ± 20% as specified in the Energy Star standard promulgated by the US Department of Energy and the US Environmental Protection Agency. This is generally considered an acceptable lighting distribution uniformity for an omnidirectional lamp, although there is some interest in extending this range even further, such as a latitude range of θ = [0 °, 150 °] with ± 10% uniformity . Such lamps with substantial uniformity over a wide range of latitude (for example, approximately θ = [0 °, 120 °] or more preferably approximately θ = [0 °, 135 °] or even more preferably approximately θ = [0 °, 150 °]) are generally considered in the art to be omnidirectional lamps, even if the uniformity range is less than [0 °, 180 °]. Similarly, directional lamps are defined as having at least 80% of their light within 0 to 120 degrees, encompassing 75% of the total 4π steared from a sphere centered on the light source. Non-directional lamps do not meet the requirements of either directional or omnidirectional lamps.
    [0011] Compared to incandescent and halogen lamps, solid-state lighting technologies such as light-emitting diode (LED) devices are highly directional in nature. For example, an LED device, with or without encapsulation, typically emits in a directional Lambertian spatial intensity distribution having an intensity that varies with cos (θ) in the range of θ [0 °, 90 °] and has a zero intensity for θ> 90 °. A semiconductor laser is even more directional in nature, and it actually emits a descriptive distribution as essentially a beam of light directed forward limited to a narrow cone around θ = 0 °.
    [0012] Another consideration for omnidirectional lamps in general lighting applications and color quality. For white lamps, it is desired to provide a white light with a desired color temperature (for example, a "cold" white light, or a "warm" white light, with the desired color temperature depending on the application, region preference geographic, or other individual choice). The supply of white light generated should also have a high color rendering index (CRI), which can be thought of as a metric for the "whiteness" quality of the light emitted. Here again, incandescent and halogen lamps had the advantage over solid-state lighting. An incandescent filament, for example, can be built to produce a good color temperature and CRI characteristics, while an LED device naturally produces an approximately monochromatic light (for example, red, or amber, or green, etc.). Including a "white" phosphor coating on the LED, a white light supply can be approximated, but the supply is still generally lower than the color temperature and CRI compared to incandescent or halogen lamps.
    [0013] Yet another challenge with solid-state lighting is the need for auxiliary components such as electronics and heat dissipation. Heat dissipation is necessary because LED devices are highly sensitive to temperature. Proper thermal management of LED devices is required to maintain operational stability and total system reliability. This is typically resolved by placing a relatively large mass of heat dissipating material (i.e., a heat sink) that contacts or otherwise makes good thermal contact with the LED device. The space occupied by the heatsink blocks the lighting, thereby further limiting the ability to generate an omnidirectional LED-based lamp. The heatsink preferably has a large volume and surface area in order to radiate heat away from the lamp - however, such an arrangement is problematic for an omnidirectional light source since a large portion of the angular range (for example, approximately θ = [0 °, 135 °] or more preferably approximately θ = [0 °, 150 °]) is devoted to the optical output, which limits the volume and available surface area. The need for a built-in electronics further complicates the project. Typically, these difficulties are resolved by accepting a negotiation between the angular range and the heat dissipation (for example, reducing the uniform light output range to something close to θ = [0 °, 90 °] and making the heat sink more close to a hemispheric element). Alternatively, the heat sink can be configured as a thermal conduction path instead of a radiator, and the electronics and heat radiators or heat dissipation located in a corresponding remote lamp device. An example of such an arrangement is shown in Japanese Publication JP 2004-186109 A2, which describes a suspended light that includes a light source and a customized device containing the required electronics and heat radiation elements to drive the source. of light. The lamp from JP 2004-186109 A2 is a "suspended light" and emits light over a latitude range of θ ~ [0 °, 90 °] or less (where in this case the "north" direction is pointing "down", that is, moving away from the ceiling).
    [0014] Despite these challenges attempts have been made to build a one-piece LED-based omnidirectional light source. This is due to the benefits that solid-state lighting exhibits over traditional light sources, such as lower energy consumption, longer life, improved robustness, smaller size and faster switching. However, LEDs require more precise control of electrical current and heat management than traditional light sources. It is known that the LED temperature must be kept low in order to ensure efficient light production, maintenance of lumens throughout life, and high reliability. If the heat cannot be removed quickly enough, the LED can become overheated, impairing its efficiency and life. In prior thermal management solutions, the large volume, mass and surface area of the required heat fins result in an integral LED lamp that has an undesirably large mass and size, as well as poor uniformity in the distribution of heat. light intensity.
    [0015] The thermal conductivity of the prior art material typical for the thermal management of LED lamps, aluminum, has approximately 80-180 W / m-K depending on the alloy and the manufacturing process. The use of a polymer as the thermal management material could reduce the weight and cost of a replacement LED lamp if the polymer's thermal conductivity could be increased. Recently, several polymer composite materials have been developed in efforts to improve thermal conductivity and total system performance in LED applications. A thermally conductive polymer-loaded compound was introduced that combines good thermal conductivity (up to 25 W / m-K) with good heat distortion temperature (HDT) and processability. However, the compounds are not transparent, and thereby block the lighting of a lamp. Alternatively, thin composite films loaded with electrically conductive transparent polymers have been developed for use on touch screens. However, these materials focus on electrical properties, and generally do not provide high thermal conductivity.
    [0016] The present description is aimed at solving the problems of weight, size and cost of thermal management in lamps and LED and OLED lighting systems, while simultaneously avoiding the blocking of light, providing the relatively high thermal conductivity of the polymers so far optically opaque in an optically transmissive polymer, and incorporating the optically transmissive polymer design into the LED or OLED lamp or lighting system. This can include creating an all-in-one solution, integrating LED lighting, thermal transfer (heat sink), reflector options, and cooling options. Specifically, the present invention is directed to the optimization of thermal transfer in an omnidirectional light source based on integral LED. An integral light source is usually a lamp or lighting system that provides all the functions required to accept electrical energy from the grid supply and create a light distributed in a lighting pattern. The integral light source is typically comprised of an electric trigger, an LED or OLED light machine to convert electricity into light, an optical component system to distribute the light in a useful pattern, and a thermal management component system to remove the waste heat from the actuator and the light machine and dissipate the heat into the environment. Heatsink performance is a function of material, geometry, and heat transfer coefficients for convection and radiation to the environment. Generally, increasing the surface area of the heatsink by adding extended surfaces such as fins will improve the thermal performance of the heatsink. However, since the purpose of the heatsink in most LED and OLED applications is to provide the coldest possible temperature of the light machine and the driver, then it is usually desirable for the heatsink to provide a very large surface area. The space occupied by the preferred heatsink design can interfere with the space required by the preferred optical system and will therefore block lighting and thereby limit the lighting potential of the lamp or lighting system. Therefore, an optimal thermal energy dissipation / disperser must incorporate high thermal conductivity together with transparency or translucency to ensure that the dissipation / dispersion surfaces will not block the light that radiates from the light source. BRIEF SUMMARY
    [0017] The modalities are described here as illustrative examples. According to an aspect of the present description, a light emitting device is provided. The light emitting apparatus includes a light transmissive envelope; a light source being in thermal communication with a heat sink, and a plurality of heat fins in thermal communication with the heat sink and extending in a direction such that the heat fins are adjacent to the transmissive light envelope. The plurality of heat fins comprises a polymer compound filled with carbon nanotubes.
    [0018] According to another aspect, the light emitting device is provided that includes a LED light source mounted on a base, a transmissive light diffuser configured to diffuse and transmit the light from the LED light source, and one or more thermally conductive heat fins in thermal communication with the base. The heat fins comprise a thermally conductive material that includes a polymer compound filled with carbon nanotubes.
    [0019] In yet another modality, a light emission device is provided. The light emitting device comprises a substrate that has one or more organic light emitting elements with a first electrode formed on it, one or more conductive layers, one or more organic light emitting layers arranged on the first electrode, a second electrode located on the light emission layers, and an encapsulation cover located on the second electrode and affixed to the substrate. At least one of the substrate and the cover is comprised of a polymer compound filled with carbon nanotubes. BRIEF DESCRIPTION
    OF THE DRAWINGS
    [0020] The invention can take shape in various components and component arrangements, in various process operations and process operation arrangements. The drawings are for the purpose of illustrating the modalities only and are not to be considered as limiting the invention.
    [0021] Figure 1 shows diagrammatically, with reference to a conventional incandescent light bulb, a coordinate system that is used here to describe the lighting distributions;
    [0022] Figure 2 diagrammatically shows a side view of a lamp based on omnidirectional LED that employs a Lambertian light source based on flat LED and a spherical diffuser;
    [0023] Figure 3 illustrates a side view of two illustrative LED-based lamps that employ the lamp principles of Figure 2 still including an Edison base that allows installation in a conventional incandescent lamp socket;
    [0024] Figure 4 illustrates a side perspective view of a modernized LED-based light bulb substantially similar to the lamp in Figure 3, but still including fins;
    [0025] Figure 5a illustrates a prior art LED replacement lamp for omnidirectional incandescent lamp applications;
    [0026] Figure 5b illustrates a prior art LED replacement lamp for directional incandescent lamp applications;
    [0027] Figure 6 shows a table of thermal conductivity of commonly used materials;
    [0028] Figure 7a graphically displays the thermal conductivity of carbon nanotubes as a function of temperature K;
    [0029] Figure 7b graphically displays the thermal conductivity for carbon nanotubes (solid line), compared to a constrained graphite monolayer (dash and dot line), and the AA graphite baseline (dotted line) at temperatures between 200 and 400 K;
    [0030] Figure 8 illustrates an organic light emitting device according to the aspects of the present description. DETAILED DESCRIPTION
    [0031] The present description is aimed at solving the problems of weight, size and cost of thermal management in lamps and LED and OLED lighting systems, while simultaneously avoiding the blocking of light providing a relatively high thermal conductivity of optically opaque polymers existing to date in an optically transmissive polymer, and incorporating the design of the optically transmissive polymer in the LED or OLED lamp or lighting system. This solution uses polymer compounds filled with carbon nanotubes of high thermal conductivity and relatively low density so that the thermal conductivity of the composite polymer is comparable to that of aluminum while the optical transmission is comparable to that of transparent glass, so that the composite polymer can be used as heat fins and thermally conductive optical elements.
    [0032] Referring to Figure 2, an LED-based lamp includes a Lambertian light source based on flat LED 8 and a spherical transmissive light envelope 10 in a configuration that could be used in an LED lamp to provide a pattern of omnidirectional lighting to replace a general purpose incandescent light bulb. However, other forms may be preferred in certain embodiments to provide other lighting patterns such as directional or non-directional lighting patterns, the flat LED 8-based Lambertian light source is best seen in the partially disassembled view of Figure 2 in which the diffuser 10 is out of the way and the Lambertian light source based on flat LED 8 is tilted in view. The Lambertian light source based on flat LED 8 includes one or more light emitting diode (LED) devices 12, 14. However, it should be recognized that this description does not simply cover use with LEDs, but with organic LEDs ( OLEDs) as well.
    [0033] The illustrated light transmissive envelope 10 is substantially hollow and has a spherical surface that diffuses light. In some embodiments, the spherical envelope 10 is comprised of glass, although a diffuser comprising another light transmitting material, such as a plastic, is also contemplated. The surface of the envelope 10 can be made to diffuse light in several ways, such as: sandblasting or other texture to promote the diffusion of light; coating with a light diffusing coating, such as a soft white diffusing coating (available from the General Electric Company, New York, USA) of a type used as a light diffusing coating on the glass bulbs of some incandescent light bulbs; embedding light scattering particles in glass, plastic, or other diffuser material; various combinations thereof; and so on.
    [0034] The Lambertian light source based on LED 8 can comprise one or a plurality of light sources (LEDs) 12, 14. Laser LED devices are also contemplated for incorporation into the lamp.
    [0035] The performance of an LED lamp can be quantified by its lifetime, as determined by its maintenance of lumen and its reliability over time. While incandescent and halogen lamps typically have lifetimes in the range ~ 1000 to 5000 hours, LED lamps are capable of> 25,000 hours, and perhaps as much as 100,000 hours or more.
    [0036] The temperature of the p-n junction in the semiconductor material from which photons are generated is a significant factor in determining the life span of an LED lamp. A long lamp life is achieved at junction temperatures of approximately 100 ° C or less, while a severely shorter life occurs at approximately 150 ° C or more, with a gradation of service life at intermediate temperatures. The power density dissipated in the semiconductor material of a typical high-brightness LED around the year 2009 (~ 1 Watt, ~ 50-100 lumens, ~ 1 x 1 mm square) is approximately 100 Watt / cm2. By comparison, the power dissipated in the ceramic envelope of a ceramic metal fin (CMH) arc tube is typically approximately 20-40 W / cm2. Whereas, the ceramic in a CMH lamp is operated at approximately 1200-1400 K at its hottest point, the semiconductor material of the LED device must be operated at approximately 400 K or less, despite having a 2x power density higher than CMH ceramic the temperature differential between the hot spot in the lamp and the environment in which the power is to be dissipated is approximately 1000 K in the case of the CMH lamp, but only approximately 100 K for the led lamp. Consequently, thermal management should be on the order of ten times more effective for LED lamps than for typical HID lamps.
    [0037] The Lambertian light source based on LED 8 is mounted on a base 18 which can be both electrical and heat dissipating. The LED devices are mounted in a flat orientation on a circuit board 16, optionally a metallic core printed circuit board (MCPCB). The base element 18 provides support for the MCPCB and is thermally conductive (heat sink). When designing a heatsink, the limiting thermal impedances in a passively cooled thermal circuit are typically the convective and radiative impedances for the ambient air (ie, the heat dissipation for the ambient air). Both impedances are generally proportional to the surface area of the heatsink. In the case of a replacement lamp application, where the LED lamp must be mounted within the same space as the traditional Edison type incandescent lamp being replaced, there is a fixed limit on the amount of available surface area exposed to ambient air . Therefore, it is advantageous to use as much of this available surface area as possible for the dissipation of heat into the ambient air.
    [0038] Referring now to Figure 3, the components of this project, which are configured as a one-piece light emitting device, are illustrated. The LED-based lamp in Figure 3 includes an Edison 30 type screw-based electrical connector that is shaped to be a direct replacement for the Edison-based electrical connector of a conventional incandescent lamp. (It is also envisaged to use another type of electrical connector, such as a bayonet mount of the type sometimes used for incandescent light bulbs in Europe). The lamps in Figure 3 include spherical or spheroidal diffusers 32, and respective flat LED-based light sources 36 tangentially arranged to a bottom portion of the respective spherical diffuser 32. The LED-based light source 36 is configured tangentially in relation to the diffusers spherical or spheroidal 32 and includes LED devices 40. In Figure 3, the LED-based light source 36 includes a small number of LED devices 40 (two illustrated), and provides a substantially Lambertian light intensity distribution that is coupled with the spherical diffuser 32.
    [0039] With continued reference to Figure 3, an electronic driver 44, is interposed between the flat LED light source 36 and the base electrical connector Edison 30, as shown in Figure 4. Electronic driver 44 is contained within a lamp base 50 with the balance of each base (that is, the portion of each base not occupied by the respective electronics, being made of a heat dissipating material. The electronic actuator 44 is sufficient, in itself, to convert the AC power received at the Edison 30 base electrical connector (for example, 110 volts AC of the type conventionally available in Edison-type lamp sockets in residential and office locations, or 220 volts AC of the type conventionally available in an Edison-type lamp socket in European residential and office locations) to a suitable shape to activate the light source based on LED 36. (It is also contemplated to employ another type of electrical connector, such as a mounting of bayonet of the type sometimes used for incandescent light bulbs in Europe).
    [0040] It is desired to make the base 50 large in order to accommodate a large volume of electronics and in order to provide adequate heat dissipation, but the base is also preferably configured to minimize the locking angle, that is, to maintain the light up to 30 ° uninterrupted. These diverse considerations are accommodated in the respective bases 50 employing a small reception area for the LED-based light source sections 36 which are dimensioned approximately the same as the LED-based light source, and which have slanted sides in less than than the desired locking angle (a truncated cone shape). The inclined base sides extend away from the LED-based light source by a sufficient distance to allow the inclined sides to meet with a cylindrical base portion of dbase diameter which is large enough to accommodate the electronics.
    [0041] It will be appreciated that the external shape of the lamps in Figures 3 and 4 is defined by the diffuser 32, the base 50 and the threaded electrical connector of the Edison 30 type are advantageously configured to have a shape (that is, a shape outward) similar to that of an Edison type incandescent light bulb. The diffuser 32 defines the portion that roughly corresponds to the "bulb" of the incandescent light bulb, the base 50 which includes the inclined sides 54 has some similarity to the base region of an Edison type incandescent light bulb, and the electrical connector threaded base type Edison 50 conforms to the standard of electrical connector type Edison.
    [0042] The angle of the heatsink base helps to maintain a uniform light distribution for high angles (for example, at least 150 °). If the cutting angle is> 30 °, it will be practically impossible to maintain a uniform distant field strength distribution at the azimuth angles (top and bottom of the lamp). Also, if the cutting angle is too shallow <15 °, there will not be enough space in the rest of the lamp to contain the electronics and the lamp base. An optimum angle of 20-30 ° is desirable to maintain uniformity of light distribution, while leaving space for the practical elements within the lamp. The LED lamp present provides a uniform output from 0 ° (above the lamp) to 150 ° (below the lamp) preferably 155 °. This is an excellent replacement for the traditional A19 incandescent light bulb.
    [0043] As shown in Figure 4, a plurality of heat radiation fins 60 can be included in thermal communication with the base 50. Thus, the lamp in Figure 4 is an integrated light emitting device adapted to be installed in a lighting device (not shown) by connecting the illustrated Edison 30 type electrical connector (or a bayonet connector or other type of electrical connector included in the integrated light emitting apparatus) to a corresponding receptacle on the lighting device. The integrated light emitting device of Figure 4 is a self-contained omnidirectional light emitting device that is not based on the lighting device for heat dissipation or the drive electronics. As such, the one-piece light emitting device of Figure 4 is suitable, for example, as a modernized light bulb. The fins 60 improve the radiative heat transfer from the base 50 to the air or other surrounding environment. Essentially, the base 50 heatsink includes extensions that comprise fins 60 that extend over the spherical diffuser 32 to further improve the radiation and convection to the environment of the heat generated by the LED chips of the LED based lighting unit 36 '. The fins 60 extend latitudinally in the direction of the north pole of the lamp θ = 0 ° adjacent to the spherical diffuser 14. The fins 60 are formed to conform to the desired external shape of an Edison type incandescent light bulb. Advantageously, the project provides an LED-based light source that mounts within an ANSE contour for an A-19 bulb. The external LED bulb is functional as a light transmitter and a dual purpose heat dissipating surface. The fins 60 mate with the base on the sloping sides 54, 56. Furthermore, there is no specific requirement for the shape of the fin.
    [0044] The heat fins 60 of Figure 4 can be comprised of aluminum, or stainless steel, or another metal or metallic alloy that has an acceptably high thermal conductivity. The heat fins 60 can have the natural color of the substrate metal, or they can be painted or coated in black or another color to improve thermal radiation, or they can be painted or coated in white or another light color to improve reflectance. visible light. However, the metallic heat fins must be minimized in size, or positioned in relation to the light source in order to reduce the adverse impact on the light distribution pattern due to the absorption and dispersion of light by the heat fins. In the application of an integral replacement lamp, having a regulated limitation on the size and shape of the lamp, such restrictions on the size, shape and location of the heat fins result in or an undesirable reduction in light output and distortion of the distribution of heat. light, or a reduction in cooling provided by the heat fins for the LED or OLED light source. In the case of an integral LED lamp intended to replace an omnidirectional incandescent lamp, the compromise that was chosen in the prior art modalities is to severely limit the range of angles of the distribution of the light output, as shown in Figures 5a-b. In the case of most replacement LED bulbs for omnidirectional incandescent lamp applications, shown in Figure 5a, the light distribution covers only approximately 1/2 of the total 4 π steradians of the preferred distribution, while the remaining 1/2 of the range angle is blocked by heat fins 60. In the case of most LED replacement bulbs for directional incandescent and halogen lamp applications, exemplified in Figure 5b, heat fins 60 are avoided from approximately 1/2 of the 4π steradians total so that the light distribution can be emitted without distortion of the heat fins 60.
    [0045] According to one embodiment, the heat fins 60 in Figure 4 are constructed of a thermally conductive material, and more preferably a composite of thermally conductive carbon nanotubes. Carbon nanotubes (CNTs) are carbon allotropes that have a cylindrical nanostructure. In general, carbon nanotubes are elongated tubular bodies that typically have only a few atoms in circumference. Both single-walled nanotubes (SWNTs) and multi-walled carbon nanotubes (MWNTs) have been recognized. MWNTs have a central tubule that surrounds graphical layers while SWNTs have only a tubule and no graphical layer. CNTs have a desirable resistance, weight, and electrical conductivity. CNTs have been found to conduct heat and electricity better than copper or gold and have 100 times the tensile strength of steel, with only 1/6 of the weight. The thermal conductivity range of CNT is typically 1000-6000 W / m-K at room temperature or slightly higher and may be of an order of magnitude at lower temperatures. However, carbon nanotubes exhibit poor dispersion and agglomeration in host materials making the use of CNTs in composite materials difficult. US 7,094,367 and US 7,479,516, incorporated herein by reference, describe some common proposals for dispersing CNTs in host polymer matrices, such as poly (methyl methacrylate), nylon, polyethylene, epoxy resin, polyisoprene, sbs rubber, polydicyclopentadiene, polytreatfluoroethylene, poly (phenylene sulfide), poly (phenylene oxide), silicon, polyketone, and thermoplastics, etc., which include a mixture of polymer solution and carbon nanotubes, a combination of sonication and fusion processing, fusion mixing, in situ polymerization in the presence of nanotubes.
    [0046] Another proposal to disperse CNTs in host polymer matrices includes braiding long strands of SWCNTs in a fabric forming a contiguous structure of high thermal conductivity carbon nanotubes. As introduced above, SWNTs are single-dimensional conductors with dimensions of approximately 1 nanometer in diameter and several micrometers in length. Long-strand SWCNTs are commercially available, such as from Eikos, Inc. Multiple layers of SWCNT fabric can be produced with a 90-95% opening if SWNTs are incorporated into a layered structure within a polymer matrix transparent so that each SWCNT yarn / cord in any fabric is perfectly placed on top of the same yarn as the fabric below. This configuration provides a substantially transparent polymer - CNT compound with high thermal conductivity. Although the CNT fabric may not be transparent, the low volume fraction and the vertical alignment of the fabrics provide sufficient transparency when looking at the polymer normally and at large angles outside the normal.
    [0047] The carbon nanotube compound described here is thermally conductive and transparent so as not to distort or reduce the light pattern of the lamp. The thermal conductivity (k) is between approximately 10-1000 W / mK, more preferably between approximately 20-300 W / mK, having a visible light transmittance of at least approximately 90%, more preferably at least 95% when the charge of carbon nanotubes is between approximately 2-10% by weight. As shown in Figure 6, the potential thermal characteristics of the polymer filled with carbon nanotubes are greatly improved over general heat sinks, and are more comparable with those of metals. Berber et al., Fully incorporated by reference, graphically presents several characteristics of a carbon nanotube compound, illustrated in Figures 7a and 7b. Figure 7a shows the thermal conductivity of CNT as a function of K temperature. As shown, CNT reaches peak conductivity at 100 K (37000 W / m-K), so the conductivity gradually decreases. At room temperature, the conductivity is approximately 6000 W / m-K. Figure 7b illustrates the thermal conductivity for carbon nanotubes (solid line), compared to a constrained graphite monolayer (dash and dot line), and the AA graphite baseline (dotted line) at temperatures between 200 and 400 K. The calculated values (solid triangles) are compared with the experimental data (open circles), (open diamonds), and (open squares) for graphite. The graph illustrates that an isolated nanotube shows a thermal transport behavior very similar to a hypothetical isolated graphene monolayer.
    [0048] The electrical characteristics of the CNT compound depend largely on the mass fraction of nanotubes (%). US 7,479,516 B2, incorporated herein by reference, teaches conductivity levels for electrical applications. '516 describes that a very small (0.03)% SWNT load in polymer for electrical applications such as electrostatic dissipation and electrostatic shielding and a 3% by weight SWNT load is suitable for EMI shielding . Therefore, the preferred physical properties and processability of the host polymer would be minimally compromised within the nanocomposite.
    [0049] In a carbon nanotube polymer compound the thermal conductivity ratio is expected to be as follows:
    [0050] kcomposite «(WT% CNT) x kcnt + (WT% PMR) x kpmr
    [0051] Where kcomposite is the thermal conductivity resulting from the compound and is expected to be 10-1000 W / m-k. kcnt is the thermal conductivity of the carbon nanotube used. kpmr is the thermal conductivity of the polymer matrix used. WT% CNT is the percentage weight load of the carbon nanotube in the compound and is expected to be 2-10%. WT% PRM is the percentage weight load of the polymer matrix in the compound. The transparency of the compound is expected to be ~ 95% as follows: Tcomposite = 1 - Rcomposite - Acomposite
    [0052] Acomposite «(VOL% CNT) x to CNT + (VOL% PMR) x A pmr
    [0053] Where the absorbance of the CNT is ~ 100% and the absorbance of the polymer matrix is ~ 0%, so that the absorbance of the compound is:
    [0054] Acomposite «(VOL% CNT) / (VOL% PMR) ~ 2-10%
    [0055] In general, carbon nanotubes are randomly oriented within a polymeric host. However, it is also contemplated to form high thermally conductive carbon nanotubes filled with polymer compound as a CNT layer in which the carbon nanotubes are polarized in the direction of a selected orientation parallel to the plane of the thermally conductive material, as described in US, deposited on April 2, 2010 (GE 244671), which is incorporated herein by reference. Such an orientation can improve the lateral thermal conductivity compared to the "through layer" thermal conductivity. If the carbon nanotubes are further polarized in the direction of a selected orientation parallel to the plane of the thermally conductive material, then the tensioner has additional components, and if the selected orientation is parallel to a described direction of thermal flow then the final radiative / convective heat dissipation efficiency can be further improved. One way to achieve this preferred orientation of carbon nanotubes is by applying an electric field E during spray coating. More generally, an external energy field is applied to the polymeric host. According to another way of achieving a preferential orientation of the carbon nanotubes, the thermally conductive layer is arranged over the heatsink body using paint, with the paint strokes being drawn along the preferred orientation in order to mechanically polarize the carbon nanotubes in the direction of the preferred orientation.
    [0056] According to another aspect of the present description, high thermal conductivity carbon nanotubes filled with polymer compound are used with an organic light emitting diode (OLED). Figure 8 shows a lower emission OLED architecture. Although Figure 8 only shows a simple configuration, OLED devices generally include a substrate 80 that has one or more OLED light emitting elements that includes an anode formed on it 84, one or more conductive layers 86, such as a hole injection layer, located above anode 84, one or more organic light emitting layers 88, an electron transport layer 90 and a cathode 92. An OLED device can be emitted from the top, where the light-emitting elements are intended to emit through a cover over the cathode, and / or emitting from the bottom where the light-emitting elements are intended to emit through the substrate. Consequently, in the case of a bottom-emitting OLED device, substrate 82 and anode layer 84 must be highly transparent, and in the case of a top-emitting OLED device, the cover and second cathode 92 must be highly transparent. OLEDs can generate efficient, high-brightness displays; however, the heat generated during the operation of the display can limit the life of the display as the light emitting materials degrade more quickly when used at higher temperatures. Therefore, according to the present modality, the polymer nanotube compounds filled with polymer can be implemented as the substrate and / or the cover to create the front and / or rear plane dispersion and heat dissipation surfaces.
    [0057] The exemplary modality has been described with reference to the preferred modalities. Obviously, modifications and changes will occur to others when reading and understanding the preceding detailed description. It is intended that the exemplary modality is considered to include all such modifications and alterations thereof that they fall within the scope of the appended claims or their equivalents.
    权利要求:
    Claims (13)
    [0001]
    1. Light-emitting apparatus comprising: a transmissive light envelope (10); an LED light source (8) in thermal communication with a heat sink (18, 50); a plurality of heat fins (60) in thermal communication with said heat sink (18, 50) and extending in one direction so that the heat fins (60) are adjacent to the light transmissive envelope (10), wherein the plurality of heat fins (60) comprises a polymer compound filled with carbon nanotubes; and characterized by the fact that said apparatus has a longitudinal axis that dissects said envelope (10) and said heat sink (18, 50), and wherein said heat sink (18, 50) has an angle of blocking of light between 15 ° and 30 ° measured from said longitudinal axis at an exit point of said heat sink (18, 50).
    [0002]
    2. Apparatus according to claim 1, characterized by the fact that the thermal conductivity of the apparatus is approximately 20-300 W / m-K.
    [0003]
    Apparatus according to claim 1, characterized by the fact that the heat fins (60) have at least approximately 90% transmittance.
    [0004]
    4. Apparatus according to claim 1, characterized by the fact that the loading of carbon nanotubes is between approximately 2-10% by weight.
    [0005]
    5. Apparatus according to claim 1, characterized by the fact that carbon nanotubes are single-walled carbon nanotubes (SWNT).
    [0006]
    6. Apparatus according to claim 5, characterized by the fact that the polymer compound filled with carbon nanotubes comprises a braided fabric with long single-walled carbon nanotube threads.
    [0007]
    Apparatus according to claim 6, characterized by the fact that the polymer compound filled with carbon nanotubes comprises multiple layers of braided fabric with long single-walled carbon nanotube threads.
    [0008]
    8. Apparatus according to claim 7, characterized by the fact that the single-walled carbon nanotubes are embedded in the multiple layers within a transparent polymer matrix so that each single-walled nanotube wire is positioned on top of the same nanotube thread as a tissue position below.
    [0009]
    9. Light-emitting device comprising: an LED light source (36) mounted on a base (50); a transmissive light diffuser (32) configured to diffuse and transmit light from the LED light source (36); and one or more thermally conductive heat fins (60) in thermal communication with the base (50), said heat fins (60) comprising a thermally conductive material that includes a polymer compound filled with carbon nanotubes; and characterized by the fact that said apparatus has a longitudinal axis that dissects an envelope (10) and said heat sink (18, 50), and wherein said heat sink (18, 50) has a locking angle of light between 15 ° and 30 ° measured from said longitudinal axis at an exit point of said heat sink (18, 50).
    [0010]
    10. Device according to claim 9, characterized in that the base includes a heat sink (18, 50) and the fins (60) extend over the diffuser.
    [0011]
    11. Device according to claim 9, characterized in that the polymer compound filled with carbon nanotubes includes a visible light transmittance of at least approximately 90%.
    [0012]
    12. Device according to claim 9, characterized by the fact that the carbon nanotubes are polarized in the direction of a parallel orientation with the plane of the thermally conductive material.
    [0013]
    13. Device according to claim 12, characterized by the fact that the carbon nanotubes are still polarized in the direction of a parallel orientation with a direction of thermal flow.
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    法律状态:
    2018-03-27| B15K| Others concerning applications: alteration of classification|Ipc: F21V 29/506 (2015.01), F21K 9/232 (2016.01), F21V |
    2019-01-08| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|
    2019-05-28| B06T| Formal requirements before examination [chapter 6.20 patent gazette]|
    2019-10-08| B06A| Patent application procedure suspended [chapter 6.1 patent gazette]|
    2020-11-10| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2021-01-19| B16A| Patent or certificate of addition of invention granted [chapter 16.1 patent gazette]|Free format text: PRAZO DE VALIDADE: 10 (DEZ) ANOS CONTADOS A PARTIR DE 19/01/2021, OBSERVADAS AS CONDICOES LEGAIS. |
    2021-11-03| B21F| Lapse acc. art. 78, item iv - on non-payment of the annual fees in time|Free format text: REFERENTE A 11A ANUIDADE. |
    2022-02-22| B24J| Lapse because of non-payment of annual fees (definitively: art 78 iv lpi, resolution 113/2013 art. 12)|Free format text: EM VIRTUDE DA EXTINCAO PUBLICADA NA RPI 2652 DE 03-11-2021 E CONSIDERANDO AUSENCIA DE MANIFESTACAO DENTRO DOS PRAZOS LEGAIS, INFORMO QUE CABE SER MANTIDA A EXTINCAO DA PATENTE E SEUS CERTIFICADOS, CONFORME O DISPOSTO NO ARTIGO 12, DA RESOLUCAO 113/2013. |
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    PCT/US2011/020744|WO2011088003A2|2010-01-12|2011-01-11|Transparent thermally conductive polymer composites for light source thermal management|
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