Date Announced: 28 Jul 2006 NeoPac announces ultra-high-power 135-watt LEDs Street Light, keeping junction temperature uniformly under 60°C as well Taking the lead in LEDs general lighting, NeoPac Lighting has announced it is to demonstrate the world’s new breakthrough outdoor LEDs lighting device – the ultra-high-power 135-watt NeoBulb Street Light at the upcoming 2nd .China (Beijing) International LED Exposition (Aug 2~4).The 135-watt NeoBulb Street Light is capable of providing 5,000 lumens output (37lm/W). It is currently the best performing outdoor LED lamp packed with more power and brightness output than before, thereby pushing LED general lighting to the highest level yet. Demonstrating the NeoPac system-in-package LEDs technology for outdoor application, it can well-control the LEDs junction temperature (Tj) at under 60 °C (lab measured and tested), even with its ultra-high power dissipation in a regular lamp size.Thermal ManagementNeoPac Lighting president Jeffrey Chen says, “This is a big technical advance, to keep all ultra-high-power LED clusters at the same heat dissipation rate, and most importantly, at uniform rate of power dissipation.”“The LEDs junction temperature (Tj) must be kept low, and also must eliminate the hot spots caused by cluster effect. It is also important to maintain all LEDs with the same temperature conditions within the P-N junction, and control at the same decay rate, so the brightness output stays uniform across”, as he explains.The lamp design is based on NeoPac’s top-rated efficiency in thermal management. It is constructed with a framework of system-in-package heat pipes and heat sink to effectively conduct the heat away from the front end LEDs out to the back side, and out to the surrounding air. This NeoPac patented design has the “magic effect” in producing a “top-warm and bottom-cool” lamp configuration.Overall, the design also had to take account to include for driver box, control, electrical circuits, power supply and other engineering components. Outdoor ApplicationsChen states that, “Producing an LED street light is the dream at the top end application for the LED industry.”Built to last with durable metal casing, it has been lab-tested to stand the natural elements for all-purpose outdoor lighting applications. It has an IP rating of 65 for dust and water protection, and would be able to function in all kinds of windy, rainy, high humidity, and sunny weather conditions. Chen explains, “It is essentially a very difficult challenge for current high-power LEDs approach to figure out a workable solution, for building a real LED street lighting device with enough brightness output for outdoor application. There are technical barriers to overcome, particularly in ultra-high power dissipation and junction temperature control. It is important to have protection from dust, water, and humidity, while able to efficiently conduct the LEDs generated heat away as well.” He points out the NeoBulb Street Light have much commercial marketing applications, because of the energy saving, long life, stability, and low maintenance cost of LED devices over conventional lighting fixtures,It can be utilized for parking lots, yards and gardens, municipal roadways, city streets, housing projects, public parks, and various other door settings with needs for high-brightness general illumination during the night time.. The head module comes to 700 mm (L) x 450 mm (W) x 200mm (H), conforming to most dimensions of standard outdoor lighting fixtures in current use.It is constructed with a base slot for mounting to lamp post of up to 10 meters in height. Chen indicates the LEDs Street Light is only the first of a whole series of NeoPac LED product lines being developed for special outdoor lighting applications. NeoBulb™ Universal Platform approachIt is seen that new breakthroughs and innovations in LED outdoor lighting can be successfully achieved through the NeoBulb™ Universal Platform framework, with its basic building unit of NeoPac® Emitters and NeoPac® Light Engines.Chen says the patented NeoBulb Street Light is very different from the current outdoor LED lights available on the market.He indicates that in order for other LED devices to offer enough brightness for outdoor lighting, it is necessary for the designed devices to pack sizable number of LED clusters for providing large enough lumen output.Chen states, “Based on the best high-power LED efficiency currently available from surface-mount assembly approaches, they would need at least 125 high-power LED light sources to achieve the 5,000 lumens output. For this large aggregate amount, there will be problems of power dissipation, heat management, and the generation of hot spots. They could not maintain the low and uniform junction temperature across the high power LED clusters like the NeoBulb Street Light can. It can only be done through the NeoPac system-in-package approach.” “To design an ultra-high-power LED Street Light with high enough lumen output, you must have excellent thermal management. The system thermal resistance must be very low. For example, at NeoPac, for the 135 W Street Light, we can control the junction temperature at 60 °C, with the ambient temperature at 25 °C. With the temperature gradient between LEDs P-N junction and ambient air at only 35 °C, and at 135 watts, the overall system thermal resistance (Rja) should be down to only 0.26 °C / w. It is virtually “Mission Impossible” to design the system by other ways. Only our system-in-package approach can manage the decay loss and maintain the brightness output at a consistent and uniform rate...... Without good thermal management to control junction temperature, it would not be a “Real” LEDs Street Light”, he adds.Size ConstraintsIn terms of technical and functional design, the demand for high-brightness lumen output and the amount of LED clusters also places constraints on the size of the final product. “For our 135-watt NeoBulb LED Street Light, its dimension (700 mm x 450 mm x 200 mm) conforms to the size of current outdoor lighting fixtures. When fixed on a 12-meter lamp post on the highway, it is about the right size when looking from the ground level,” as Chen explains.For other approaches of LED outdoor lighting without efficient heat management and control of junction temperature, they would need large amount of LED clusters, up to 100’s to reach the high illumination output of over 5,000 lumens. However, to make for better power dissipation, the size of this device would be too large and too heavy to hang up on outdoor lamp posts. Overall, high-brightness outdoor lighting is one of the top targets for the industry, but Chen states that there are still some ways to arrive at the ideal goal.Improved Brightness Output He points out, “Right now with 5,000 lumens output, it is still not good enough for highway lighting at the 12-meter high level. It needs to improve to higher brightness illumination.”Chen stresses that NeoBulb™ Universal Platform is the basis for reaching the goal, “In effect, we are building an “ultra-high-power LEDs outdoor platform”. We are trying to set a standard format for LEDs outdoor applications.” “Within next year in 2007 as NeoPac® Emitter efficacy will achieve up to 75 lumens per watt. Therefore NeoPac is able to offer ultra-high-power LEDs outdoor lighting with 10,000 lumens output in 2007. This would be good enough, for the high brightness requirement on outdoor illumination on city streets and public construction projects,” according to Chen.
Contact
Clement Yang, NeoPac Lighting Tel: +886-3-558-3620 ext. 220 Fax: +886-3-558-6909
E-mail:[email protected]
Web Site:http://www.neopac-lighting.com
