TW201405067A - Structure of plastic heat sink for LED bulb and method of making the same - Google Patents

Abstract

A plastic heat sink for LED bulb is disclosed. The LED bulb is comprised of a substrate, LED chips, lamp cover, lamp base, driver and plastic heat sink. The plastic heat sink is formed by injection molding and/or with insert molding, using polycarbonate or polyolefin-based compounds containing high thermally-conductive fillers. The heat sink further includes (a) metal ring with/without modification by insert molding in order to enhance the heat dissipation capability. The heat sink is electrically-insulated and flame retarded. Furthermore, the LED bulb is capable of releasing far-infrared ray.

Description

Light-emitting diode bulb structure with plastic lamp shell and plastic fins and its system Method

The invention relates to a light-emitting diode lamp, in particular to a light bulb structure of a plastic lamp shell.

The issue of energy conservation and carbon reduction and the issue of oil and gas double rise have recently become fever. China's lighting industry is also constantly developing new technologies. In addition to the already popular fluorescent tubes and the increasingly high power-saving bulbs, the life span is over 20,000 hours and unit watts. A number of high-lumen LED lights are naturally one of the main candidates that people can think of against high electricity prices.

LED lamps have a longer service life than conventional lamps and fluorescent tubes. However, long life is required for the LED driver components, wafers and substrates to dissipate heat well. The wafer of the LED luminaire is a low temperature luminescence. However, LED lamps or tubes usually have multiple LEDs to achieve the surface light source, and the typical method is to attach the LED chip to a printed circuit board (PCB), and the back side of the printed circuit board is attached to the aluminum plate and the aluminum is connected. Extruded or die-cast fins. Therefore, as long as the heat generated by the injection current of the LED chip is difficult to dissipate heat, the heat generated by the LED lamp is accumulated in the lamp housing, and the light is degraded early. Therefore, LED bulbs almost all contain aluminum extruded or aluminum die-cast fins to provide heat dissipation. The above-mentioned various reasons are the main reason for the high price of LED lamps.

As mentioned above, LED lighting currently uses die-casting fins as heat-dissipating components. Although aluminum is relatively light metal, the fins made of this material are still quite bulky. Moreover, it is not easy to process and form as described above. Another aluminum itself is also electricity Good conductor. Therefore, although the driving voltage of a single LED is less than 4V, in many cases, a plurality of LED chips are used in series and in parallel to achieve the lumens required for illumination use. Therefore, the overall current voltage (power) of the driving elements of the LED is not low. In order to consider the safety problems such as electric shock, some manufacturers adopt insulated plastic coated or isolated driving components to ensure the safety of electrical appliances. Please refer to the sectional view of the LED light bulb in Figure 1-1. From top to bottom, the cover 10, the LED chip 20, the ceramic substrate (or PCB) 30, the electric wire 40, the insulating coated plastic 50, the LED driving component (transformer) 60, and the aluminum lamp housing 80 (including the aluminum heat sink fin 81) ) and metal joints (lamps) 70.

Such a structure, in addition to causing an increase in cost (the plastic 50 of the package driving component, the material and manufacturing cost of the aluminum lamp housing 80 (including the heat dissipation fins 81)), also tends to cause poor heat dissipation of the driving components, resulting in detrimental operation of the driving components or must be strengthened. The area of the heat sink fins. All of the above are the main reasons why the price of LED lamps is still high and not easy to fall sharply.

Another cross-sectional view of the LED bulb shown in Figures 1-2 and 1-3, although the plastic is used as the lamp housing, but the inside of the lamp housing is metal, the metal can be a ring-shaped middle tube or a π -type middle tube, when the LED The substrate temperature is higher than the driving component, and a temperature gradient is generated between the substrate and the driving component, and the thermal energy is transmitted to the driving component through the metal inside the lamp housing, which may cause the temperature of the driving component to rise and reduce the service life.

In view of the problems of the prior art, the present invention discloses a heat-conductive plastic with a high surface resistance as a lamp housing, so that the driving component can transmit heat to the heat-conducting lamp by contact or by heat transfer of air without covering the plastic. The shell and the inner side of the lamp housing are made of heat-conductive plastic (not metal) to promote heat dissipation of the driving element, and to extend the service life and safety. And because the lamp housing is made of plastic, it is easy to process or form, which not only reduces the cost but also reduces the cost (price).

The object of the present invention is to provide a light-emitting diode lamp structure with a plastic lamp housing, the LED lamp comprising an aluminum substrate, at least one light-emitting diode (LED) chip on the substrate, a lamp cover, a metal joint and a plastic lamp The plastic lamp housing has the effect of heat conduction and insulation, so that it is not required to additionally cover the driving component, and the plastic lamp housing can even achieve excellent heat dissipation performance and flame retardant effect (UL94 V1 or higher, the plastic lamp housing can be gathered Carbonate (PC) or polyolefin filler metal, metal oxide powder or other non-metal oxide. The plastic lamp housing has an upper surface that is in contact with the substrate. The upper surface of the plastic lamp housing is placed in the metal during the molding process. After the ferrule is placed in the mold to be positioned, the plastic is injected to embed the metal into the plastic lamp housing (insert molding) to form an integrally formed metal-containing plastic lamp housing, and the upper planar surface can be coated. Thermal grease, heat sink or heat sink to enhance heat dissipation and adhesion to the substrate. The upper surface can also be selectively embedded in metal, metal or gold after molding the plastic lamp housing. The metal piece, the metal ring or the metal collar is buried in the plastic lamp housing (not to the bottom of the plastic lamp housing). In addition, the upper outer side wall of the plastic lamp housing can be selectively embedded in the metal sheet. Promote the heat conduction of the lamp housing to the substrate. The plastic lamp housing can be integrally formed and has high surface resistance (insulation) regardless of the package. It can be injection molded and can be recycled and reused; the lamp cover is flat, concave or Convex or light covers angles up to 270 degrees (full-circle lampshade), and the light transmission can be matte or transparent.

The invention is characterized in that the plastic metal lamp shell is used to replace the general metal aluminum shell and the aluminum heat dissipating fin, and the driving component does not need to be covered with the insulating material, so there is no problem of poor heat dissipation, and the invention has the advantages of easy processing, light weight and low cost. Personalized color, environmental protection and other advantages.

Further, another feature of the present invention is that the plastic lamp housing is capable of releasing far infrared rays.

Please refer to the cross-sectional view of the LED lamp with the plastic lamp housing of the present invention shown in FIG. 2. As shown in FIG. 2, the LED lamp of the present invention includes a lampshade 10, an LED chip 20, a substrate 30, a wire 40, an LED driving component (transformer) 60, and a plastic lamp housing 85 (including heat sink fins 86 integrally formed). And the lamp holder 70. The lampshade 10 is a light emitting surface of the LED and may be a matte surface to reduce the point light source property of the LED. The substrate 30 may be a PCB (printed circuit board) substrate having an LED wafer carrier and a circuit pattern, and the lower portion of the PCB substrate 30 is attached to an aluminum substrate to provide better heat transfer capability.

The upper portion of the plastic lamp housing 85 of the present invention is a flat surface 85A parallel to the aluminum substrate (hereinafter referred to as the upper surface 85A of the lamp housing). The flat surface of the plastic lamp housing 85A is placed in the mold of the desired position during the molding process, and the plastic is injected to embed the metal into the plastic lamp housing (insert molding) to form an integral molding. Metal-containing plastic lamp housing (as shown in the cross-sectional views of Figures 2 and 3). The upper planar surface 85A is also selectively embedded in the metal sheet, the metal ring or the metal collar 92 after the plastic lamp housing is formed. For example, in FIG. 2, the metal collar 92 has a cross-section, and the cross section of the metal collar 92 in FIG. In the shape of π, the cross section of the metal collar in FIG. 4 exhibits a double T shape. In FIG. 5, the metal collar 92 has an inverted L-shaped cross section, and in FIG. 6, a metal piece or a metal ring 92. The horizontal plane described here is that the upper plane is in direct contact with the substrate 30, and the vertical plane (from top to bottom) is embedded in the plastic lamp housing 85 (without the bottom surface of the plastic lamp housing).

The reason that the metal piece, the metal ring or the metal collar 92 does not contact the driving element is that the heat generated by the LED chip illuminating causes the substrate temperature to be generally higher than the driving element, The difference in temperature creates a temperature gradient between the substrate and the drive element, and heat is transferred to the drive element by the metal inside the lamp envelope, which in turn increases the temperature of the drive element and reduces life. In order to avoid the above problems, the metal piece, the metal ring or the metal collar of the present invention is embedded/embedded in the plastic lamp housing, but does not reach the bottom surface of the plastic lamp housing, and the heat generated by the LED chip illumination is transmitted to the substrate and the metal piece, After the metal ring or the metal collar 92 is cooled by the lamp housing plastic, the heat generated by the driving component 60 is transmitted to the outside of the lamp housing 85 by the plastic inside the lamp housing 85. In addition, a thermal conductive paste or a thermal conductive sheet can be selectively used between the lower side of the driving element and the LED base to promote heat dissipation of the driving element. The upper planar surface 85A may be coated with a thermal grease, a thermal grease or a heat sink (not shown) to enhance heat dissipation and adhesion to the substrate 30. The substrate 30 is screwed to the upper surface 85A of the lamp housing, and the substrate 30 may be a metal substrate or a ceramic substrate. The surface of the lamp housing 85A can be selectively coated with some thermal grease to enhance the adhesion. The substrate 30 may also be a metal substrate. The upper surface 85A of the plastic lamp housing 85 of the present invention can provide support for the metal substrate 30. Please refer to the perspective view of the plastic lamp housing 85 including the upper surface 85A of the lamp housing shown in FIG. In Fig. 7, the lamp housing upper surface 85A is provided with an outlet hole 88, four screw holes 87, and an annular hole 90.

Please note that in the above structure, the present invention does not have the conventional insulating coated plastic 50. This is because the present invention employs a plastic lamp housing 85 (including heat sink fins 86). The plastic lamp housing 85 is composed of a plastic material filled with metal, metal oxide powder or non-metal carbide, nitride or oxide powder, and has electrical insulation. The plastic material may be selected from polycarbonate (PC) or polyolefin, and the filler material is selected from the group consisting of silver, aluminum, gold, copper, nickel, zinc, aluminum nitride, aluminum oxide, cerium oxide, and magnesium oxide. a metal or metal oxide such as zinc oxide or tungsten carbide or a tungsten carbide powder. Non-metal oxides or carbides, nitride powders include boron nitride, diamond, graphite, tantalum carbide, tantalum nitride, etc. end. The plastic lamp housing 85 is composed of a plastic material mixed with the above-mentioned filler material powder and has an insulation resistance of more than 4KV, a surface impedance of more than 1E+9 Ω/sq, and meets the flame retardant effect of the UL94 V2 or higher standard; UL94 V2 refers to the US insurance. The fire-proof standard set by the manufacturer must be extinguished within 30 seconds during the combustion test, but the drip plastic can ignite the surgical cotton. The higher standards are UL94 V1 and V0. UL94 V1 and UL94 V0 respectively mean that the combustion test must be extinguished within 30 and 10 seconds, but the drip plastic cannot ignite the surgical cotton. The plastic lamp housing 85 material to which the present invention pertains also conforms to the UL94 V1 and V0 standards.

For example, the above-mentioned mixing ratio of the plastic material and the filling material is about 5 to 45% by weight of the polyolefin, and the filling material is 35 to 95%. For more details, please refer to another patent application of the applicant, the Republic of China. The patent application number is 100140804.

Between the lamp housing and the connecting metal connector 70, there is a height of the cylinder 91 of 0.1 cm or more (see Fig. 2 to Fig. 6) to improve the aesthetic appearance of the plastic lamp housing. Since it is a plastic lamp housing 85, the cost and weight are reduced compared to the conventional aluminum lamp housing. The lamp envelope can be easily fabricated, whether simple or special, because the present invention is a plastic lamp housing 85 that can be easily transferred to produce the plastic lamp housing 85 of the present invention. The hole 88 and the plastic lamp housing 85 are formed at one time. For example, the plastic lamp housing 85 may have a plurality of fins 86 on the outside, or may not be presented at all by the fins 86. The conventional aluminum processing cost is high, and the special shape is relatively cost-effective and economical.

In another embodiment, the lamp housing upper surface 85A is provided with a plurality of holes 89, or annular holes 90. A ring-shaped columnar metal piece, a metal ferrule 92 or a plurality of combined columnar metal pieces 92 are pressed into the annular hole 90 or the elongated metal ring piece 92. The columnar metal piece can increase the heat dissipation area, and the insulating and thermally conductive plastic of the present invention has good thermal conductivity (thermal conductivity of about 1 W/m-K to 3 W/m-K). Metal sheet 92, The metal ferrule 92 or the metal ring piece 92 does not require additional wires. The 92 is embedded in the plastic lamp housing 85, and the received heat can be directly dissipated by the large-area plastic lamp housing 85.

The invention also provides a method for manufacturing an LED lamp, the steps are as follows: First, the plastic material, the filler material powder and the dye are mixed and processed and cut to form a plastic pellet. Among them, the weight ratio of the plastic material and the filler material powder enables the plastic lamp shell to achieve at least UL94 V2 flame retardancy, the surface impedance is greater than 1E+9 Ω/sq, the withstand voltage is greater than 4 KV, and the thermal conductivity is at least greater than 1 W. Selected by /mK, the dye is mixed in the plastic granules. After injection molding, the plastic lamp housing 85 directly has a predetermined color without further coloring.

Next, a plastic lamp shell molding die is prepared, and a metal ferrule is preset at a preset portion of the molding die, and the metal ferrule has a cross-section of a ㄇ shape (Fig. 2) and a π shape (Fig. 3). The preset portion of the molding die is, for example, an annular hole of the upper surface 85A, or a predetermined hole of the upper surface 85A, so that the plastic lamp housing contains a metal collar after being injected into the plastic (embedded molding/in-mold) forming). Therefore, the cost of rework can be reduced. Of course, it is also possible to press the metal sheet (ring) after the plastic lamp housing is molded. Of course, this will add extra costs.

Next, an injection molding technique is applied to the plastic pellets to project a plastic lamp housing onto the mold.

Separating the plastic lamp housing from the mold, and then mounting a light-emitting diode (LED) wafer on the upper surface of the plastic lamp housing, wherein the lower surface of the substrate and the upper surface of the plastic lamp housing are coated with some thermal grease and heat dissipation. Glue or use a heat sink to make the two fit better. Next, an LED driving component is installed inside the plastic lamp housing from the lower outlet of the plastic lamp housing, and a power cord is passed through the upper portion. The plane is connected to the LED substrate.

Subsequently, a metal connector is connected to the lower portion of the plastic lamp housing with an adhesive to provide an external power source to be input to the power input end of the LED driving component; finally, a lamp cover is connected to the upper surface of the plastic lamp housing to form Finished LED lamps.

The composition of the LED lamp plastic lamp housing 85 of the present invention contains a substance having a high far-infrared emissivity. Therefore, when the composition of the plastic lamp housing 85 is in a natural environment, there is a release of far-infrared rays without additional coating or deal with. The far infrared rays can be released. Figure 10 shows the relationship with emissivity in the wavelength range of (4 to 14 m; visible to far infrared). The test conditions were based on the composition of the plastic lamp housing 85 and tested with a Vertex 70 FT-IR spectrometer. The test was carried out at a temperature of 85 ° C and an ambient temperature of 25 ° C and a relative humidity of 60%.

The LED lamp of the invention has the following advantages:

1) The plastic lamp housing 85 has a high surface resistance of plastic, but has a heat dissipation performance close to metal and a flame retardant effect.

2) The heat-dissipating fins on the plastic lamp housing 85 are also flame-retardant and heat-conductive plastics, which can be formed by injection molding and can be recycled and reused.

3) The aluminum lamp housing and the aluminum heat sink fin are replaced by a plastic lamp housing 85, which is relatively light in weight, low in material cost and processing cost.

4) The metal piece, metal ring or metal ring embedded in the flat surface 85A of the lamp housing can promote the heat transfer of the LED chip, the LED substrate and the LED driving component to the heat dissipation fin.

5) The LED drive component is in direct contact with the plastic lamp housing and is completely insulated. It does not require additional plastic housing packaging and there is no danger of electric shock.

6) The plastic lamp housing is completed by one-time molding/in-mold molding (integral molding), which can reduce processing, manpower and energy saving.

7) There is a cylinder height of 0.1 cm or more between the heat sink fin and the connecting metal joint to make it look like a plastic lamp shell.

8) The color of the plastic lamp shell can be mixed with the dyes that have been reserved according to the needs of consumers in the plastic grain stage. No additional coloring is required, the cost is reduced, and the selling phase can be increased.

The present invention has been described above by way of a preferred example, but it is not intended to limit the spirit of the invention and the inventive subject matter. Those who are familiar with the technology can easily understand and utilize other components or methods to produce the same effect. Modifications made without departing from the spirit and scope of the invention are intended to be included within the scope of the appended claims.

10‧‧‧shade

20‧‧‧LED chip

30‧‧‧Substrate

40‧‧‧Wire

50‧‧‧Insulation coated plastic

60‧‧‧LED drive components

80‧‧‧Aluminum lamp housing

81‧‧‧Aluminum heat sink fins

85‧‧‧ plastic lamp housing

90‧‧‧Circular holes

86‧‧‧Plastic cooling fins

88‧‧‧Outlet hole

92‧‧‧metal piece (ring) or metal ring

87‧‧‧ screw holes

91‧‧‧Cylinder

Figure 1-1 shows a cross-sectional view of a conventional LED luminaire.

Figure 1-2 shows a cross-sectional view of a conventional LED luminaire.

Figures 1-3 show cross-sectional views of conventional LED luminaires.

2 shows a cross-sectional view of an LED luminaire having a plastic lamp envelope made in accordance with the present invention.

Figure 3 shows a cross-sectional view of an LED lamp with a plastic lamp envelope made in accordance with the present invention.

4 shows a cross-sectional view of an LED lamp with a plastic lamp housing made in accordance with the present invention.

Figure 5 shows a cross-sectional view of an LED luminaire having a plastic lamp envelope made in accordance with the present invention.

Figure 6 shows a cross-sectional view of an LED luminaire having a plastic lamp envelope made in accordance with the present invention.

Figure 7 shows a perspective view of a plastic lamp housing made in accordance with the present invention to illustrate an annular hole in the upper plane.

Figure 8 shows a perspective view of a plastic lamp housing made in accordance with the present invention.

Figure 9 shows a cross-sectional view of a plastic lamp housing made in accordance with the present invention showing a metal sheet (ring) or metal ferrule in a hole or recess.

Figure 10 is a graph showing the relationship between the emissivity and the wavelength of a plastic lamp envelope manufactured in accordance with the present invention, showing that the plastic lamp envelope can emit far infrared rays.

10‧‧‧shade

20‧‧‧LED chip

30‧‧‧Substrate

40‧‧‧Wire

60‧‧‧LED drive components

70‧‧‧Metal joints

86‧‧‧Plastic cooling fins

85‧‧‧ plastic lamp housing

85A‧‧‧Light shell upper plane

91‧‧‧Cylinder

Claims (10)

An LED lamp, the plastic lamp housing of the LED lamp can release far infrared rays, comprising: a substrate having an LED circuit pattern; one or more LEDs on the LED circuit pattern on the substrate; an LED a driving component for connecting an external power source, and converting the external power source into an input power required for driving the LED chips on the LED circuit pattern; a plastic lamp housing for accommodating the substrate, the LED driving component The plastic lamp shell is made of flame-retardant heat-conducting but electrically insulating material, and the plastic lamp shell has a flat surface on the lamp housing and the substrate is fitted, and the light-emitting surface of the lamp shell is provided with a hole in addition to the power output line of the LED driving component. Thereby traversing the connection substrate and having additional holes to embed the metal piece or the metal collar to increase the heat dissipation capability, the inner side of the lamp case is plastic; a lamp cover is connected to the upper part of the plastic lamp housing, and is located at the (some) Above the LED chip, to provide light; and a metal connector is connected to the lower portion of the plastic lamp housing, an external power source is provided for input, and the external power source is input to the input end of the LED driving element. The LED lamp of claim 1, wherein the material of the plastic lamp housing comprises a plastic material and a filling material, wherein the plastic material is selected from the group consisting of polycarbonate (PC) and polyolefin. The filler material is selected from the group consisting of metals, metal oxides, non-metal oxides, non-metal carbides, non-metal nitride powders, and any mixture thereof. Any of the plastic lamp housings have a flame retardancy of UL94 V2 or higher, a surface impedance of more than 1E+9 Ω/sq, a thermal conductivity of more than 1 W/m-K, and an insulation withstand voltage of more than 4 KV. The LED lamp of claim 1, wherein the plastic lamp housing further comprises a plurality of heat dissipation fins formed thereon, and the plastic lamp housing is integrally formed with the heat dissipation fins, and the heat dissipation fins The lower edge and the metal joint have a cylindrical height of 0.1 cm or more. The LED lamp of claim 1, wherein the metal piece, the metal ring or the metal ring is buried in the plastic lamp housing and smaller than the longitudinal surface of the plastic lamp housing. The LED lamp of claim 1, wherein the LED driving component and the lamp housing have a heat dissipating fin or a heat dissipating glue for promoting heat dissipation. A method for manufacturing an LED lamp, wherein the plastic lamp shell of the LED lamp can release far infrared rays, at least comprising the steps of: providing plastic particles, wherein the plastic particles are processed by mixing a plastic material and a filling material powder, wherein the plastic material The weight ratio of the material and the filler powder is selected according to the requirement that the plastic lamp shell can achieve at least UL94 V2 flame retardancy, the surface impedance is greater than 1E+9 Ω/sq, the thermal conductivity is at least greater than 1 W/mK, and Release a far infrared ray; providing a plastic lamp housing molding die, presetting a first metal piece at a preset portion of the molding die, the first metal collar having a cross section selected from the group consisting of a ㄇ font and a π font One of the plastic lamp shell molding molds is used as a mold, and the plastic pellets are subjected to injection molding technology to integrally form the metal-containing plastic lamp shell (buried molding/in-mold molding); A polar body (LED) chip is mounted on an upper surface of the plastic lamp housing; an LED driving component is mounted inside the plastic lamp housing from a lower outlet of the plastic lamp housing, and a power line is connected through the upper plane LED substrate; a metal connector adapters in the lower portion of the plastic lamp housing to thereby provide input to the external power supply input terminal of the LED driving device; and a lampshade connected to the plane of the plastic housing of the lamp, to form the LED lamp. The method for manufacturing an LED lamp according to claim 6, further comprising mixing a dye on the plastic pellet, so that the molded plastic lamp envelope has a predetermined color. The method for manufacturing an LED lamp according to claim 6, wherein the plastic material and the filling material are mainly composed of one of polycarbonate (PC) and polyolefin, and the filling material is selected from the group consisting of Any of a group consisting of a metal, a metal oxide, a non-metal oxide, a non-metal carbide, a non-metal nitride powder, and any mixture thereof A method for manufacturing an LED lamp comprises at least the steps of: providing plastic granules, the plastic granules being a mixture of a plastic material, a filler material powder, and a dye, wherein the weight ratio of the plastic material and the filler material powder is based on the plastic lamp The shell can at least achieve a flame retardancy of UL94 V2 or higher, the surface impedance is 1E+9 Ω/sq, and the thermal conductivity is at least greater than 1W/mK. The dye provides the final finished color; a plastic lamp housing is provided. a mold, the mold includes a fin shape, so that the heat sink fin is integrally formed, and the plastic lamp shell is molded at a predetermined place Reserving the hole; the plastic lamp shell molding die is used as a mold, and the plastic pellets are injection molded to integrally form the plastic lamp shell; and a light emitting diode (LED) wafer is mounted on the plastic lamp shell An LED driving component is mounted in the plastic lamp housing through a lower outlet of the plastic lamp housing, and a power cable is connected to the LED substrate through the upper plane; a metal connector is connected to the lower portion of the plastic lamp housing. An external power source is provided to be input to the power input end of the LED driving component; and a lamp cover is connected to the upper surface of the plastic lamp housing to form the LED lamp. The method for manufacturing an LED lamp according to claim 9, further comprising pressing a first metal piece on a reserved portion of the hole of the plastic lamp case to increase heat dissipation capability, wherein the first metal piece is selected from a metal One of a group consisting of a ring piece, a plurality of metal pieces, and both.