> Quick answer: Aluminium-core metal-core printed circuit boards (MCPCBs) are used in high-lumen solar lamps due to their superior thermal conductivity, reducing LED junction temperature and improving lumen maintenance. FR-4 and ceramic substrates are unsuitable for such applications [1][17].
High-lumen solar lamps rely on efficient heat management systems to maintain optimal performance and longevity. The choice of PCB substrate plays a crucial role in this process. While different materials offer various advantages, aluminium-core MCPCBs stand out as the preferred option due to their high thermal conductivity.
Why Aluminium-Core Substrates Are Preferred
High-lumen solar lamps predominantly utilize aluminium-core metal-core printed circuit boards (MCPCBs) or, in advanced configurations, high-purity aluminium plates used as integrated heat sinks [1][5][6][7]. These materials are chosen because they offer significantly better thermal conductivity compared to FR-4 and ceramic substrates.
Thermal Conductivity Comparison
The dielectric material in FR-4 acts as a thermal barrier, leading to hotspots when heat-generating devices like LEDs are mounted directly on it [1]. This makes FR-4 unsuitable for high-power LED systems. Ceramic substrates, while beneficial in UV-LED applications due to their resistance to short-wavelength light degradation, have limited use in general-purpose solar lamps due to their low thermal conductivity of around 25 W/m·K [17].
In contrast, aluminium-core MCPCBs feature a metal core (aluminum or copper) with a thermally conductive dielectric layer, allowing the board to function as a heat spreader. The high-purity aluminium plates used in one-piece, monolithic heat sinks have thermal conductivities exceeding 230 W/m·K [5][6][7][11]. This higher conductivity ensures efficient heat transfer away from the LED chip, thereby maintaining optimal performance.
| Substrate Type | Thermal Conductivity (W/m·K) |
|–––––|––––––––––|
| FR-4 | 0.2 – 3 |
| Aluminium-Core MCPCB | 95 |
| Ceramic | ~25 |
How Thermal Conductivity Affects LED Performance
The thermal conductivity of the substrate directly influences LED junction temperature, which is critical for both lumen maintenance and operational lifetime [1][3]. Every 10°C rise above the maximum operating temperature can reduce LED lifetime by up to 50% [16]. High junction temperatures also lead to reduced light output and color shift, degrading system performance.
Using a substrate with high thermal conductivity—such as high-purity aluminium—reduces thermal resistance, enabling faster heat transfer away from the LED chip. This directly contributes to lower junction temperatures, which in turn improves lumen maintenance and extends the operational lifetime of the solar lamp [1].
Innovative Design Features
The design of the heat sink further enhances thermal management. High-purity aluminium heat sinks are not just substrates but integrated systems with features like radiating holes and channels that promote natural convection [5][11]. These channels allow air to flow smoothly, preventing heat accumulation and improving dissipation [12].
Moreover, the tight contact between the circuit board and the heat sink surface ensures efficient heat transfer. In some designs, the circuit board is mounted directly on the heat sink with no thermal interface material (TIM), reducing thermal resistance further [8]. When TIMs are used, they are typically thermally conductive adhesives or silicone grease, though their thermal conductivity is limited to about 1 W/m·K.
Cost and Efficiency Considerations
A surprising finding from recent research is that a simpler, monolithic aluminium plate design can outperform traditional die-cast aluminium heat sinks in both efficiency and cost. High-purity aluminium plates used in one-piece heat sinks achieve superior heat dissipation with only 1/3 to 1/5 the material, half the weight, and 1/2 to 1/3 the cost of conventional die-cast aluminium [5][6][7][11].
Key Takeaways
- Aluminium-core substrates are the preferred choice for high-lumen solar lamps due to their superior thermal conductivity.
- High-purity aluminium plates with over 95% aluminium content provide exceptional heat dissipation, reducing junction temperature and improving lumen maintenance.
- The design of integrated heat sinks enhances performance through features like radiating holes and channels that promote natural convection.
Frequently Asked Questions
[
{„q”: „How does thermal conductivity affect LED lifetime in solar lamps?”, „a”: „Higher thermal conductivity helps maintain lower junction temperatures, reducing the risk of degradation. Every 10°C above optimal can halve the LED’s lifespan [16].”},
{„q”: „What are the advantages of using high-purity aluminium plates over traditional die-cast aluminium?”, „a”: „High-purity aluminium plates offer better heat dissipation and cost efficiency, weighing half as much and costing up to 30% less than conventional designs [5][6][7][11].”},
{„q”: „Can FR-4 substrates be used in high-lumen solar lamps?”, „a”: „No, FR-4 is not suitable due to its poor thermal properties. It can lead to hotspots and reduced performance [1].”}
]
References
- [1] LEDs_Shine_On_Through_Thermal_Management_Electronic_Design__08aae28a — magazine
source passage
also be made in terms of thermal resistance, which measures the temperature rise through the material for a given amount of applied power, such as 1.2°C/W, referenced to specific convection flow conditions. A PCB, such as FR-4, combines electrically/thermally conductive materials (copper conductors) and more electrically/thermally resistive materials (dielectric material). The high thermal resistance of the dielectric material results in hotspots if thermal management isn’t applied to heat-generating devices such as LEDs. In some cases, PCBs are fabricated with metal backsides and plated through holes (PTHs) from the circuit side to provide a thermal path. For applications with high-power (high-temperature) LEDs, PCBs will often feature a metal-core (MC) base. Such PCBs typically use a thermally conductive metal, such as aluminum or copper, as the supporting substrate. The PCB also incorporates a thermally conductive thin dielectric layer that helps a mounted LED transfer heat through the PCB and allows the board to function as a heat spreader. While this represents effective thermal management at the PCB level, it’s also more expensive than a standard PCB. Often, the heat flow from LEDs through a PCB must be assisted by additional materials and structures, such as thermally conductive adhesive materials and other thermal interface materials (TIMs), heat sinks, and heat pipes. LEDs are usually encapsulated in a transparent resin material, which is a poor thermal conductor, so
- [3] Thermal_management_of_high-power_LEDs_-_Wikipedia__c07ec6ab — wikipedia
source passage
2.6 °C/W to 18 °C/W, depending on the LED manufacturer. The thermal interface material’s (TIM) thermal resistance will also vary depending on the type of material selected. Common TIMs are epoxy, thermal grease, pressure-sensitive adhesive and solder. Power LEDs are often mounted on metal-core printed circuit boards (MCPCB), which will be attached to a heat sink. Heat conducted through the MCPCB and heat sink is dissipated by convection and radiation. In the package design, the surface flatness and quality of each component, applied mounting pressure, contact area, the type of interface material and its thickness are all important parameters to thermal resistance design. Some considerations for passive thermal designs to ensure good thermal management for high power LED operation include: Adhesive is a thermal conductive interface layer,[5] which is commonly used to bond LED and board, and board and heat sinks and further optimizes the thermal performance. Current commercial adhesive is limited by relatively low thermal conductivity ~1 W/(mK). Heat sinks provide a path for the heat from the LED source to outside medium. Heat sinks can dissipate power in three ways: – conduction – heat transfer from one solid to another – convection – heat transfer from a solid to a moving fluid, which for most LED applications will be air – radiation – heat transfer from two bodies of different surface temperatures through Thermal radiation. Also, heatsink: – Material – The thermal conductivi
- [5] US9810416B2_-_Method_for_manufacturing_a_lamp-housing-type__dea72050 — patent
source passage
⅓ to ⅕ of the materials used by conventional die-cast aluminum. The cost of the present invention is only ½ to ⅓ of that of conventional die-cast aluminum. The weight of the lighting device made in the lamp housing of the present invention is also less than half of the conventional one made of die-cast housing. For example, the lighting industry usually adopts high purity aluminum plates of 1050, 1060 and 1070. The heat conductivity of pure aluminum is 237 W/m·K. Aluminum content of 1050 aluminum plate is 99.5% with heat conductivity of 209 W/m·K. Aluminum content of 1060 aluminum plate is 99.6% and the heat conductivity of it should be between 1050 aluminum plate and 1070 aluminum plate. Aluminum content of 1070 aluminum plate is 99.7% with heat conductivity of 226 W/m·K. The heat conductivity of high purity aluminum plate is greatly higher than that of the sectional aluminum which is about 209 W/m·K and much higher than that of die-cast aluminum which is about 95 W/m·K. Therefore, the heat-sink of the present invention provides an excellent heat dissipation effect. For a traditional die-cast aluminum LED bulb or PAR lamp, the circuit board and the lamp-housing-type heat-sink usually contact with each other with only a small area. Heat cannot be transmitted smoothly from the circuit board to the lamp-housing-type heat-sink on this arrangement. Unlike the conventional art, the lamp-housing-type heat-sink 2 of the present invention is composed of a heat-sinking surface 21 and
- [6] US9810416B2_-_Method_for_manufacturing_a_lamp-housing-type__dea72050 — patent
source passage
punched in the middle of the plate could also be a semi-sphere on which several cavities are punched to place the LED circuit board. Compared with the existing technologies, the present invention has the following advantages: First, the lamp-housing-type heat-sink in an LED lighting device is made monolithically by extending a high purity aluminum plate with a thickness of 0.5 mm to 5 mm and an aluminum content of above 95%. This can achieve the same and even better heat diffusion effect with ⅓ to ⅕ of the materials required by die-cast aluminum, and the cost will only be ½ to ⅓ of that required by die-cast aluminum. The heat conductivity of the high purity aluminum plate with aluminum content of above 95% is over 230 W/(m·K), contributing to a higher heat dissipation efficiency compared with die-cast aluminum and sectional aluminum. Moreover, the weight of the lighting device made in the lamp-housing-type heat-sink of the present invention is less than half of one having a die-cast housing. Because the present invention requires less material consumption, costs are lowered. Therefore, the LED lighting device of the present invention is of lower price, lighter weight, and wider application, namely that it can be applied to lighting devices of various models and types. Second, the circuit board and lamp-housing-type heat-sink contact each other through a tightly contacted surface. The heat generated by the circuit board can be rapidly dissipated into air through the high purit
- [7] US9810416B2_-_Method_for_manufacturing_a_lamp-housing-type__dea72050 — patent
source passage
plate with a thickness of 0.5 mm to 5 mm and an aluminum content of above 95%. – This can achieve the same and even better heat diffusion effect with 1 ⁇ 3 to 1 ⁇ 5 of the materials required by die-cast aluminum, and the cost will only be 1 ⁇ 2 to 1 ⁇ 3 of that required by die-cast aluminum. – the heat conductivity of the high purity aluminum plate with aluminum content of above 95% is over 230 W/(m ⁇ K), contributing to a higher heat dissipation efficiency compared with die-cast aluminum and sectional aluminum. – the weight of the lighting device made in the lamp-housing-type heat-sink of the present invention is less than half of one having a die-cast housing. Because the present invention requires less material consumption, costs are lowered. Therefore, the LED lighting device of the present invention is of lower price, lighter weight, and wider application, namely that it can be applied to lighting devices of various models and types. – the circuit board and lamp-housing-type heat-sink contact each other through a tightly contacted surface. – the heat generated by the circuit board can be rapidly dissipated into air through the high purity aluminum plate of high heat conductivity, which contributes to excellent heat dissipation efficiency. – the LED luminescent lamp and the LED driving device are separated to prevent heat accumulation. Namely, in the heat dissipation channel I, heat is conducted to the heat-sinking surface through the contact surface between the circuit b
- [8] Thermal_management_of_high-power_LEDs_-_Wikipedia__c07ec6ab — wikipedia
source passage
Isothermalize a natural convection heat sink, increasing its efficiency and reducing its size. In one case, adding five heat pipes reduced the heat sink mass by 34%, from 4.4 kg to 2.9 kg.[7] – Efficiently transform the high heat flux directly under an LED to a lower heat flux that can be removed more easily.[8] – MCPCB – Metal Core PCB are the boards, which incorporate a metal material base as heat spreader as an integral part of the circuit board. The metal core usually consists of aluminum or copper alloy. Furthermore MCPCB can take advantage of incorporating a dielectric polymer layer with high thermal conductivity to reduce thermal resistance. – Separation – Separating the LED drive circuitry from the LED board prevents the heat generated by the driver from raising the LED junction temperature. – Additive Process – Thick film is a selective additive deposition process which uses material only where it is needed. A more direct connection to the Al heat sink is provided; therefore thermal interface material is not needed for circuit building. Reduces the heat spreading layers and thermal footprint. Processing steps are reduced, along with the number of materials and amount of materials consumed. – Insulated Aluminum Materials System – Increases thermal connectivity and provides high dielectric breakdown strength. Materials can be fired at less than 600 °C. Circuits are built directly onto aluminum substrates, eliminating the need for thermal interface materials. Through im
- [11] US9810416B2_-_Method_for_manufacturing_a_lamp-housing-type__dea72050 — patent
source passage
invention is also less than half of the conventional one made of die-cast housing. – the lighting industry usually adopts high purity aluminum plates of 1050, 1060 and 1070. – the heat conductivity of pure aluminum is 237 W/m ⁇ K. – Aluminum content of 1050 aluminum plate is 99.5% with heat conductivity of 209 W/m ⁇ K. – Aluminum content of 1060 aluminum plate is 99.6% and the heat conductivity of it should be between 1050 aluminum plate and 1070 aluminum plate. – Aluminum content of 1070 aluminum plate is 99.7% with heat conductivity of 226 W/m ⁇ K. – the heat conductivity of high purity aluminum plate is greatly higher than that of the sectional aluminum which is about 209 W/m ⁇ K and much higher than that of die-cast aluminum which is about 95 W/m ⁇ K. Therefore, the heat-sink of the present invention provides an excellent heat dissipation effect. – the circuit board and the lamp-housing-type heat-sink usually contact with each other with only a small area. Heat cannot be transmitted smoothly from the circuit board to the lamp-housing-type heat-sink on this arrangement. – the lamp-housing-type heat-sink 2 of the present invention is composed of a heat-sinking surface 21 and a housing body 22 , and the heat-sinking surface 21 and the circuit board 3 forms a contact surface structure. On the housing body 22 , several radiating holes are formed which could provide a heat dissipation channel. – the radiating holes set on the housing body 22 are strip holes 23 for heat dissipat
- [12] US9810416B2_-_Method_for_manufacturing_a_lamp-housing-type__dea72050 — patent
source passage
air smoothly and prevent them from accumulating within the lamp, which leads to excellent heat dissipation. Moreover, the two channels are independent from each other, and have no influence with each other. The optical glass can be dodging optical glass or secondary grading optical glass, which could be fixed with screw or glue-pasted on the lamp-housing-type heat-sink. The circuit board is a module with flat bottom which contacts the heat-sinking surface of the lamp-housing-type heat-sink. Preferably, the two surfaces are painted with silicone grease with high conductivity. A second method for manufacturing a lamp-housing-type heat-sink in an LED lighting device includes the following steps: (1) Blank: take an high purity aluminum plate with a thickness of 0.5 mm to 5 mm and an aluminum content of above 95% according to the pre-designed size and blank the plate to external profile needed by the housing; (2) First spin: spin the high purity aluminum plate into an open hollow piece. The size of the open end of the work blank should not be smaller than the one of the closed end after spinning; (3) Second spin: spin the work blank processed above to reduce the diameter of the open end and spin the open end into the predesigned radian; (4) Blank: Blank the side surface of the work blank processed above to get hollow high purity aluminum housing. Between Step (1) and Step (2), the method includes: First type punch forming: in the middle of the plate, punch out a sinking area to co
- [16] LEDs_Shine_On_Through_Thermal_Management_Electronic_Design__08aae28a — magazine
source passage
for thermal management. For example, standard LED lights typically replace traditional incandescent bulbs for indoor lighting applications. Though operating at much lower power levels (less than 10 W) than incandescent bulbs, they still require thermal management. LEDs used in other applications, such as outdoor lighting and ceiling lights, have higher power levels (and thus generate more heat), which demands more comprehensive thermal-management solutions like larger heat sinks. Heat can wreak havoc on an LED, since excess heat will impact performance and operating life expectancy. Every 10°C rise above the maximum operating-temperature limit can reduce an LED’s lifetime by as much as 50% (Fig. 2). Higher operating temperatures also result in reduced lighting efficiency for an LED, with less light output at higher LED PN junction temperatures. Furthermore, the operating temperature can affect the color of light produced by an LED. For spectrum-sensitive applications, the optical wavelength of an LED can shift with increasing operating temperature, with elevated operating temperatures contributing to poor system performance or even system failures. 2. Useful operating lifetimes of high-brightness white LEDs will vary as a function of operating temperature. Simply put, effective thermal management becomes more important as the industry moves to higher-power/brightness LEDs and higher-density LED arrays, which are generating more power and heat in smaller spaces. Practical ther
- [17] Cambridge_Nanotherm_addresses_UV-LED_thermal_management__82748c2f — magazine
source passage
# Cambridge Nanotherm addresses UV-LED thermal management challenges – News Source: Blog/Web URL: https://compoundsemiconductor.net/article/101405/Cambridge_Nanotherm_addresses_UV-LED_thermal_management_challenges Author: Date: 2017-05-23 Cambridge Nanotherm addresses UV-LED thermal management challenges Thermal management company Cambridge Nanotherm has launched Nanotherm DMS, a direct-metallised single-sided thermal management solution for UV-LED modules. UVA LEDs are rapidly displacing traditional UV lamps in the industrial printing industry, speeding up print times and reducing cost. UVC LEDs are also opening up applications like portable sterilisation units that can provide millions with clean drinking water, or let you sterilise your toothbrush when you're camping. However, UV LEDs present a significant thermal challenge. UVC LEDs often only convert 5 percent of power into photons. The remainder must be conducted away as heat via the base of the LED to a thermally conductive PCB to avoid the LED die overheating. As shorter wavelengths of UV light degrade organic material the choice of PCB is often limited to inorganic materials, discounting cost-effective metal-clad PCBs (MCPCBs) that rely on an organic epoxy based dielectric layer. Ceramics such as Al2O3 or AIN are used, but they present a conundrum to LED designers – low-performance but cost-effective Al2O3 (25W/mK), or high-performance but expensive AlN (140-170W/mK). Ceramic is also brittle and prone to cracking, fa
also be made in terms of thermal resistance, which measures the temperature rise through the material for a given amount of applied power, such as 1.2°C/W, referenced to specific convection flow conditions. A PCB, such as FR-4, combines electrically/thermally conductive materials (copper conductors) and more electrically/thermally resistive materials (dielectric material). The high thermal resistance of the dielectric material results in hotspots if thermal management isn’t applied to heat-generating devices such as LEDs. In some cases, PCBs are fabricated with metal backsides and plated through holes (PTHs) from the circuit side to provide a thermal path. For applications with high-power (high-temperature) LEDs, PCBs will often feature a metal-core (MC) base. Such PCBs typically use a thermally conductive metal, such as aluminum or copper, as the supporting substrate. The PCB also incorporates a thermally conductive thin dielectric layer that helps a mounted LED transfer heat through the PCB and allows the board to function as a heat spreader. While this represents effective thermal management at the PCB level, it’s also more expensive than a standard PCB. Often, the heat flow from LEDs through a PCB must be assisted by additional materials and structures, such as thermally conductive adhesive materials and other thermal interface materials (TIMs), heat sinks, and heat pipes. LEDs are usually encapsulated in a transparent resin material, which is a poor thermal conductor, so
2.6 °C/W to 18 °C/W, depending on the LED manufacturer. The thermal interface material’s (TIM) thermal resistance will also vary depending on the type of material selected. Common TIMs are epoxy, thermal grease, pressure-sensitive adhesive and solder. Power LEDs are often mounted on metal-core printed circuit boards (MCPCB), which will be attached to a heat sink. Heat conducted through the MCPCB and heat sink is dissipated by convection and radiation. In the package design, the surface flatness and quality of each component, applied mounting pressure, contact area, the type of interface material and its thickness are all important parameters to thermal resistance design. Some considerations for passive thermal designs to ensure good thermal management for high power LED operation include: Adhesive is a thermal conductive interface layer,[5] which is commonly used to bond LED and board, and board and heat sinks and further optimizes the thermal performance. Current commercial adhesive is limited by relatively low thermal conductivity ~1 W/(mK). Heat sinks provide a path for the heat from the LED source to outside medium. Heat sinks can dissipate power in three ways: – conduction – heat transfer from one solid to another – convection – heat transfer from a solid to a moving fluid, which for most LED applications will be air – radiation – heat transfer from two bodies of different surface temperatures through Thermal radiation. Also, heatsink: – Material – The thermal conductivi
⅓ to ⅕ of the materials used by conventional die-cast aluminum. The cost of the present invention is only ½ to ⅓ of that of conventional die-cast aluminum. The weight of the lighting device made in the lamp housing of the present invention is also less than half of the conventional one made of die-cast housing. For example, the lighting industry usually adopts high purity aluminum plates of 1050, 1060 and 1070. The heat conductivity of pure aluminum is 237 W/m·K. Aluminum content of 1050 aluminum plate is 99.5% with heat conductivity of 209 W/m·K. Aluminum content of 1060 aluminum plate is 99.6% and the heat conductivity of it should be between 1050 aluminum plate and 1070 aluminum plate. Aluminum content of 1070 aluminum plate is 99.7% with heat conductivity of 226 W/m·K. The heat conductivity of high purity aluminum plate is greatly higher than that of the sectional aluminum which is about 209 W/m·K and much higher than that of die-cast aluminum which is about 95 W/m·K. Therefore, the heat-sink of the present invention provides an excellent heat dissipation effect. For a traditional die-cast aluminum LED bulb or PAR lamp, the circuit board and the lamp-housing-type heat-sink usually contact with each other with only a small area. Heat cannot be transmitted smoothly from the circuit board to the lamp-housing-type heat-sink on this arrangement. Unlike the conventional art, the lamp-housing-type heat-sink 2 of the present invention is composed of a heat-sinking surface 21 and
punched in the middle of the plate could also be a semi-sphere on which several cavities are punched to place the LED circuit board. Compared with the existing technologies, the present invention has the following advantages: First, the lamp-housing-type heat-sink in an LED lighting device is made monolithically by extending a high purity aluminum plate with a thickness of 0.5 mm to 5 mm and an aluminum content of above 95%. This can achieve the same and even better heat diffusion effect with ⅓ to ⅕ of the materials required by die-cast aluminum, and the cost will only be ½ to ⅓ of that required by die-cast aluminum. The heat conductivity of the high purity aluminum plate with aluminum content of above 95% is over 230 W/(m·K), contributing to a higher heat dissipation efficiency compared with die-cast aluminum and sectional aluminum. Moreover, the weight of the lighting device made in the lamp-housing-type heat-sink of the present invention is less than half of one having a die-cast housing. Because the present invention requires less material consumption, costs are lowered. Therefore, the LED lighting device of the present invention is of lower price, lighter weight, and wider application, namely that it can be applied to lighting devices of various models and types. Second, the circuit board and lamp-housing-type heat-sink contact each other through a tightly contacted surface. The heat generated by the circuit board can be rapidly dissipated into air through the high purit
plate with a thickness of 0.5 mm to 5 mm and an aluminum content of above 95%. – This can achieve the same and even better heat diffusion effect with 1 ⁇ 3 to 1 ⁇ 5 of the materials required by die-cast aluminum, and the cost will only be 1 ⁇ 2 to 1 ⁇ 3 of that required by die-cast aluminum. – the heat conductivity of the high purity aluminum plate with aluminum content of above 95% is over 230 W/(m ⁇ K), contributing to a higher heat dissipation efficiency compared with die-cast aluminum and sectional aluminum. – the weight of the lighting device made in the lamp-housing-type heat-sink of the present invention is less than half of one having a die-cast housing. Because the present invention requires less material consumption, costs are lowered. Therefore, the LED lighting device of the present invention is of lower price, lighter weight, and wider application, namely that it can be applied to lighting devices of various models and types. – the circuit board and lamp-housing-type heat-sink contact each other through a tightly contacted surface. – the heat generated by the circuit board can be rapidly dissipated into air through the high purity aluminum plate of high heat conductivity, which contributes to excellent heat dissipation efficiency. – the LED luminescent lamp and the LED driving device are separated to prevent heat accumulation. Namely, in the heat dissipation channel I, heat is conducted to the heat-sinking surface through the contact surface between the circuit b
Isothermalize a natural convection heat sink, increasing its efficiency and reducing its size. In one case, adding five heat pipes reduced the heat sink mass by 34%, from 4.4 kg to 2.9 kg.[7] – Efficiently transform the high heat flux directly under an LED to a lower heat flux that can be removed more easily.[8] – MCPCB – Metal Core PCB are the boards, which incorporate a metal material base as heat spreader as an integral part of the circuit board. The metal core usually consists of aluminum or copper alloy. Furthermore MCPCB can take advantage of incorporating a dielectric polymer layer with high thermal conductivity to reduce thermal resistance. – Separation – Separating the LED drive circuitry from the LED board prevents the heat generated by the driver from raising the LED junction temperature. – Additive Process – Thick film is a selective additive deposition process which uses material only where it is needed. A more direct connection to the Al heat sink is provided; therefore thermal interface material is not needed for circuit building. Reduces the heat spreading layers and thermal footprint. Processing steps are reduced, along with the number of materials and amount of materials consumed. – Insulated Aluminum Materials System – Increases thermal connectivity and provides high dielectric breakdown strength. Materials can be fired at less than 600 °C. Circuits are built directly onto aluminum substrates, eliminating the need for thermal interface materials. Through im
invention is also less than half of the conventional one made of die-cast housing. – the lighting industry usually adopts high purity aluminum plates of 1050, 1060 and 1070. – the heat conductivity of pure aluminum is 237 W/m ⁇ K. – Aluminum content of 1050 aluminum plate is 99.5% with heat conductivity of 209 W/m ⁇ K. – Aluminum content of 1060 aluminum plate is 99.6% and the heat conductivity of it should be between 1050 aluminum plate and 1070 aluminum plate. – Aluminum content of 1070 aluminum plate is 99.7% with heat conductivity of 226 W/m ⁇ K. – the heat conductivity of high purity aluminum plate is greatly higher than that of the sectional aluminum which is about 209 W/m ⁇ K and much higher than that of die-cast aluminum which is about 95 W/m ⁇ K. Therefore, the heat-sink of the present invention provides an excellent heat dissipation effect. – the circuit board and the lamp-housing-type heat-sink usually contact with each other with only a small area. Heat cannot be transmitted smoothly from the circuit board to the lamp-housing-type heat-sink on this arrangement. – the lamp-housing-type heat-sink 2 of the present invention is composed of a heat-sinking surface 21 and a housing body 22 , and the heat-sinking surface 21 and the circuit board 3 forms a contact surface structure. On the housing body 22 , several radiating holes are formed which could provide a heat dissipation channel. – the radiating holes set on the housing body 22 are strip holes 23 for heat dissipat
air smoothly and prevent them from accumulating within the lamp, which leads to excellent heat dissipation. Moreover, the two channels are independent from each other, and have no influence with each other. The optical glass can be dodging optical glass or secondary grading optical glass, which could be fixed with screw or glue-pasted on the lamp-housing-type heat-sink. The circuit board is a module with flat bottom which contacts the heat-sinking surface of the lamp-housing-type heat-sink. Preferably, the two surfaces are painted with silicone grease with high conductivity. A second method for manufacturing a lamp-housing-type heat-sink in an LED lighting device includes the following steps: (1) Blank: take an high purity aluminum plate with a thickness of 0.5 mm to 5 mm and an aluminum content of above 95% according to the pre-designed size and blank the plate to external profile needed by the housing; (2) First spin: spin the high purity aluminum plate into an open hollow piece. The size of the open end of the work blank should not be smaller than the one of the closed end after spinning; (3) Second spin: spin the work blank processed above to reduce the diameter of the open end and spin the open end into the predesigned radian; (4) Blank: Blank the side surface of the work blank processed above to get hollow high purity aluminum housing. Between Step (1) and Step (2), the method includes: First type punch forming: in the middle of the plate, punch out a sinking area to co
for thermal management. For example, standard LED lights typically replace traditional incandescent bulbs for indoor lighting applications. Though operating at much lower power levels (less than 10 W) than incandescent bulbs, they still require thermal management. LEDs used in other applications, such as outdoor lighting and ceiling lights, have higher power levels (and thus generate more heat), which demands more comprehensive thermal-management solutions like larger heat sinks. Heat can wreak havoc on an LED, since excess heat will impact performance and operating life expectancy. Every 10°C rise above the maximum operating-temperature limit can reduce an LED’s lifetime by as much as 50% (Fig. 2). Higher operating temperatures also result in reduced lighting efficiency for an LED, with less light output at higher LED PN junction temperatures. Furthermore, the operating temperature can affect the color of light produced by an LED. For spectrum-sensitive applications, the optical wavelength of an LED can shift with increasing operating temperature, with elevated operating temperatures contributing to poor system performance or even system failures. 2. Useful operating lifetimes of high-brightness white LEDs will vary as a function of operating temperature. Simply put, effective thermal management becomes more important as the industry moves to higher-power/brightness LEDs and higher-density LED arrays, which are generating more power and heat in smaller spaces. Practical ther
# Cambridge Nanotherm addresses UV-LED thermal management challenges – News Source: Blog/Web URL: https://compoundsemiconductor.net/article/101405/Cambridge_Nanotherm_addresses_UV-LED_thermal_management_challenges Author: Date: 2017-05-23 Cambridge Nanotherm addresses UV-LED thermal management challenges Thermal management company Cambridge Nanotherm has launched Nanotherm DMS, a direct-metallised single-sided thermal management solution for UV-LED modules. UVA LEDs are rapidly displacing traditional UV lamps in the industrial printing industry, speeding up print times and reducing cost. UVC LEDs are also opening up applications like portable sterilisation units that can provide millions with clean drinking water, or let you sterilise your toothbrush when you're camping. However, UV LEDs present a significant thermal challenge. UVC LEDs often only convert 5 percent of power into photons. The remainder must be conducted away as heat via the base of the LED to a thermally conductive PCB to avoid the LED die overheating. As shorter wavelengths of UV light degrade organic material the choice of PCB is often limited to inorganic materials, discounting cost-effective metal-clad PCBs (MCPCBs) that rely on an organic epoxy based dielectric layer. Ceramics such as Al2O3 or AIN are used, but they present a conundrum to LED designers – low-performance but cost-effective Al2O3 (25W/mK), or high-performance but expensive AlN (140-170W/mK). Ceramic is also brittle and prone to cracking, fa