Abstract: At present, LED lighting is the biggest technical problem is the cooling problem, poor heat dissipation led to LED drive power, electrolytic capacitors have become the further development of LED lighting fixtures, LED light source premature aging reasons.
LED lighting is currently the biggest technical problem is the cooling problem, poor heat dissipation led to LED drive power, electrolytic capacitors have become the further development of LED lighting fixtures, LED light source premature aging reasons.
In the use of LVLED light source of the lamp program, the LED light source work in the low voltage (VF = 3.2V), high current (IF = 300-700mA) working condition, heat is very powerful, the traditional lighting space is small, small area of heat It is difficult to derive heat quickly. Despite the use of a variety of cooling programs, the results are unsatisfactory, as a LED lighting without a solution problem. Looking for easy to use, good thermal conductivity, and low-cost thermal materials are always in the effort.
At present, LED light source after power, about 30% of the energy into light energy, the rest into heat so it should be so much heat as soon as possible to export LED lighting structure design is the key technology, heat needs through heat conduction, thermal convection, heat radiation Can be distributed. Only as soon as possible to export heat in order to effectively reduce the temperature inside the LED lamps in order to protect the power supply is not in a long-term high temperature environment, in order to avoid the LED light source due to long-term high temperature work and premature aging.
LED lighting the cooling way
Because the LED light source itself is not infrared, ultraviolet light, so the LED light source itself does not radiant cooling function, LED lighting cooling way only with the LED lamp beads plate close combination of heat sink to derive heat. Radiator must have the function of heat conduction, thermal convection, heat radiation.
Any radiator, in addition to the heat can be quickly transferred from the heat source to the surface of the radiator, the most important thing is to rely on convection and radiation to heat the heat to the air. Thermal conductivity only solves the heat transfer path, and thermal convection is the main function of the radiator, heat dissipation performance is mainly determined by the ability of heat dissipation area, shape, natural convection strength, heat radiation is only auxiliary role. In general, if the heat from the heat source to the radiator surface distance is less than 5mm, then as long as the material thermal conductivity is greater than 5, the heat can be derived, the rest of the heat must be dominated by thermal convection.
Most LED lighting sources still use low voltage (VF = 3.2V), high current (IF = 200-700mA) LED lamp beads, because the work of high heat, you must use a higher thermal conductivity of aluminum. Usually die-cast aluminum radiator, extruded aluminum radiator, stamping aluminum radiator. Die-cast aluminum radiator is a pressure casting parts of the technology, the liquid zinc copper and aluminum alloy poured into the die-casting machine feed port, die-casting machine die-casting, casting mold design in advance shape of the radiator.
Die-cast aluminum radiator
Production costs can be controlled, the cooling wings can not be thin, it is difficult to maximize the cooling area. LED lamp radiator commonly used die-casting materials for the ADC10 and ADC12.
Extruded aluminum radiator
Is the liquid aluminum through a fixed mold extrusion molding, and then the bar by machining the need to cut into the shape of the radiator, the latter part of the higher processing costs. The extruded aluminum radiator is shown in Fig. The cooling wings can be done a lot of thin, the area of heat to get the greatest expansion, the cooling wing work automatically form air convection to diffuse heat, cooling effect is better. Common materials are AL6061 and AL6063.
Stamping aluminum radiator
Is through the punch and die on the steel, aluminum alloy sheet stamping, pulled up, making it into a cup of the radiator, stamping the radiator inside and outside the smooth, due to wingless and cooling area is limited. Commonly used aluminum alloy material is 5052,6061,6063. Stamping parts of the quality is very small, high utilization of materials, is a low-cost program.
Aluminum heatsink thermal conductivity is ideal, more suitable for isolated switching constant current power supply. For non-isolated switch constant current power supply, the need for the design of the lamp through the AC and DC, high voltage and low voltage power supply isolation, in order to pass CE or UL certification.
Plastic aluminum radiator
Is a heat-conductive plastic shell aluminum core radiator. Thermal plastic and aluminum heat sink in the injection molding machine on a molding, aluminum thermal core to do the pieces, the need for pre-mechanical processing. The heat of the LED lamp beads is quickly conducted through the aluminum heat sink to the thermally conductive plastic, which uses its multi-wing to form air convection heat, using its surface to radiate some heat.
Plastic aluminum radiator general use of thermal plastic original color white and black, black plastic plastic aluminum radiator radiation cooling effect better. Thermal conductivity of a thermoplastic material, material flow, density, toughness, strength are easy to injection molding, has a good resistance to cold and heat impact cycle characteristics, excellent insulation properties. Thermal conductivity of plastic radiation is better than ordinary metal materials. Thermal plastic density than cast aluminum and ceramic 40% smaller, the same shape of the radiator, plastic aluminum can reduce the weight of nearly one-third; compared with the aluminum radiator processing costs are low, short processing cycle, low processing temperature; Finished products are not fragile; customer-owned injection molding machine can be differentiated lighting design and production. Plastic aluminum radiator insulation performance is good, easy to pass safety regulations.
High thermal conductivity plastic radiator
High thermal conductivity plastic radiator recently developed rapidly, high thermal conductivity plastic radiator A plastic radiator, its thermal conductivity than ordinary plastic several times higher, up to 2-9w / mk, with excellent heat conduction, thermal radiation ; Can be applied to a variety of power lamps of the new insulation heat dissipation material, can be widely used in 1W ~ 200W various types of LED lamps.
High thermal conductivity of plastic pressure level up to AC 6000V, suitable for non-isolated switch constant current power supply, HVLED high voltage linear constant current power supply. So that this type of LED lighting easy to pass CE, TUV, UL and other strict safety inspection. HVLED using high voltage (VF = 35-280VDC), small current (IF = 20-60mA) working condition, HVLED lamp beads of heat and therefore reduced. High thermal conductivity plastic radiator using the traditional injection molding, extruder can be. A molding, finished high finish. Greatly enhance the efficiency, flexible design flexibility, can give full play to the designer's design philosophy. High thermal conductivity plastic radiator with PLA (corn starch) polymerization, complete degradation, no residue, no chemical pollution, the production process without any heavy metal pollution, no sewage, no waste gas, in line with global environmental requirements.
Highly conductive plastic radiator internal PLA molecules between the nano-scale metal ions, at high temperatures can be fast movement, increase the heat radiation energy. Its vitality is better than metal material radiator. High thermal conductivity plastic radiator high temperature, 150 ℃ five hours without rupture, no deformation, with high-voltage linear constant current IC driver program applications, no electrolytic capacitors and large volume inductance, a substantial increase in LED lamp life, non-isolated power supply program, high efficiency ,low cost. Especially for fluorescent tubes, high power mining lamp applications.
High thermal conductivity plastic radiator can design a lot of precision cooling wings, cooling wings can be done a lot of thin, the largest area of heat expansion, cooling wings automatically form air convection to diffuse heat, cooling effect is better. LED lamp beads of heat through the high thermal conductivity of plastic directly to the cooling wings, through the air convection and surface radiation rapid cooling.
High thermal conductivity plastic radiator density lighter than aluminum. Aluminum density is 2700kg / m3, while the plastic density of 1420kg / m3, almost half of the aluminum, so the same shape of the radiator, plastic radiator weight only aluminum 1 / And the processing is simple, the molding cycle can be shortened by 20-50%, which also reduces the cost of power.