Audi R8 LED Headlights - Tech Dept

Are incandescent headlights on their last flicker? They lit the road ahead for almost a century, but interest in incandescence, or light made with heat by pushing current through a thin filament, is going cold.

 

Light-emitting diodes, or Leds, promise greater light for less power and waste heat. A

lready used in taillights and turn signals, the LEDs’ steadily improving efficiency means this technology is moving up to the big job. They’ll be the standard-equipment headlights on the 2010 Audi R8 V-10 and optional on the V-8 R8. U.S. prices aren’t finalized, but ­Europeans will pay about $5000 for the set.

Why is Audi pursuing this technology? Simple: LEDs make more light than heat and take up less space. There is another benefit, too: LEDs can be arranged into whatever shapes designers and engineers demand—especially important to a style-leading brand such as Audi.

The common incandescent halogen bulb shines by electrifying and superheating a tungsten filament sealed in halogen gas. Less than five percent of the power consumed results in light, the rest is heat that is wasted. The ratio is somewhat better with high-intensity-discharge, or HID, headlights, where instead of passing over a solid filament, the current arcs between two filaments through a cloud of light-amplifying xenon gas.

Instead of incandescent, an LED is electroluminescent. Light is produced by electrifying a material, in this case a silicon chip, which is treated to be a diode, or a conductor through which electrons flow only one way. Varying the voltage to both sides of the diode excites the electrons, and their movement creates photons, or light.

Thanks to chip improvements, LED output is whiter and also brighter, from 15 lumens per watt in 2001, when Audi started its research, to 60 today, says Audi’s light engineering director, Stephan Berlitz. In the R8, the LEDs are clustered—14 for the low beam, eight for the high beam—and cooled by fans to keep internal temps below a diode-killing 300 degrees F. The fans also circulate warm air to defrost the lenses on cold mornings.

Berlitz says costs will remain high until more automakers adopt LED technology. Until then, LED hype will generate more heat than light.

New LED Lights Have a Bright Future for Communication

The University of California, Riverside will lead a multi-campus effort that could reshape the way we communicate and navigate in homes, offices, airports and yes – even the way billboards might contact us on city streets.

http://www.ledlightsliving.com/led-neon-flex-lights-c-87_104.html

The Center for Ubiquitous Communication by Light (UC-Light) will be funded with $3.5 million from the Multicampus Research Program and Initiatives (MRPI) competition within the University of California system.

“PDAs, HDTV, information kiosks, computers and laptops all can be interconnected wirelessly through visible light,” said Zhengyuan Xu, a professor of electrical engineering at the Bourns College of Engineering, the principal investigator and director of the new research center.

He will work with researchers with expertise in communication, navigation, transportation, networking, and circuit integration from UC Riverside, UC Berkeley, UC Davis, UC Merced and the Lawrence Berkeley National Laboratory to take advantage of the communication properties presented by led lights.

The project is anticipated to begin in January 2010 and run for five years.

Xu said the potential impacts of the research are huge. “With a proper data interface to a wired data network such as Ethernet, they make it possible to build very low-cost communication and navigation systems on existing Lighting infrastructure.”

The research results will likely have implications for current broadband wireless communication, HDTV signals, traffic navigation and directions, retrieving information via cell phones from electronic billboards, or allowing the refrigerator light to transmit information about what is needed on the next trip to the grocery store. Results will be especially important in areas where radio frequencies are limited, such as hospitals and airplanes.

“The visible light spectrum is several orders of magnitude larger than the crowded radiofrequency (RF) spectrum, and thus has huge potential for low cost and high data rate communication,” Xu said.

Discoveries will lead to an increase in related intellectual property, which would foster further technology transfer from the university to the commercial world, and could replace or supplement current wireless communication networks.

The Center will establish an advisory board consisting of invited experts and representatives from industry, government and academia. The researchers will consult advisory board members informally throughout the year, and the board will have a formal face-to-face meeting once per year.

Just like centralized heating systems contributed to the proliferations of rooms in a house, the advent of indoor plumbing contributed to the emergence of modern bathrooms and kitchens, and most dramatically the advent of the electric safety elevator allowed architects to design tall buildings; the advent of communication through common light sources could lead to a difference in the way houses and offices are designed.

Design a low-cost, high-performance LED driver

As Led production costs fall, they're being used more frequently in applications ranging from handheld devices, to automotive, to architectural Lighting. Their high reliability (operational lifetimes of greater than 50,000 hours), good efficiency (175 Lumens/W), and nearly instantaneous response make them a very attractive light source. However, driving LEDs is not without its challenges.

A controlled brightness requires driving the LED with a constant current, which must be maintained regardless of input voltage. Quite often, LEDs have a dimming requirement. For instance, it may be desirable to dim a display or architectural lights. There are two ways to accomplish this: either vary the LED current, or use pulse width modulation (PWM). The least effective way is varying the current because the light output isn't completely linear with current and the LED color spectrum tends to shift at currents below full rating.

It's important to remember that human perception of brightness is exponential, requiring a large percentage change in current for full dimming. This has a profound impact on the circuit design as a 3% regulation error at full current can become a 30% or more error at 10% load due to circuit tolerances. Dimming current waveform through PWM is more accurate, although the response speed becomes an issue. In lighting and displays, it's desirable to PWM above 100 Hz so the human eye doesn't perceive flicker.

Figure 1 shows a very simple, low-cost, buck regulator driving a single LED that implements a very fast dimming feature. This is based on a MC33063 which has an internal switch, a current-limit comparator, an oscillator, and an internal reference. A disable function is provided by the pin that's usually used for voltage regulation. In this scenario, a voltage greater than 1.25 V disables the supply while a lower voltage enables it. With the circuit enabled, the controller operates in a current limit/hysteretic mode, because voltage feedback has been eliminated.

http://www.ledlightsliving.com/

1. This MC33063 forms the heart of a low-cost led driver.

The oscillator generates a start pulse that causes the power switch to be turned on. This puts the input voltage across the current sense resistor, LED, and inductor. The current-limit comparator senses when the current reaches about 350 mA and turns off the power switch. The inductor voltage reverses and flies above the input voltage, causing the freewheeling diode to conduct. The inductor and LED current continue to circulate until the switch turns on at the next switching cycle. This circuit is very adaptable for a wide range of applications. Using a switching regulator with a voltage rating of 40 V and a current rating of 1.5 A is useful in handheld portable devices, white goods, and automotive applications where simplicity and low cost are desirable. The basic topology could be adapted for a wider range of applications although it may be a challenge to implement the hysteretic control and enable functions so simply.

 

 

2. As shown, the hysteretic current control provides rapid PWM response. In the images, the green represents the output current, while the blue represents the PWM signal. The top image shows 500 us/div, while the bottom image shows 10 us/div.

The circuit of Figure 1 has been built and tested. Figure 2 shows the disable command and the resulting LED current waveform. The LED can easily be PWM dimmed at 500 Hz. Rise time and fall time of the current waveform is less than 100 μs. If higher ripple current could be tolerated in the LED, the inductor could be made a smaller value and the rise time and fall times could be improved. However, 500-Hz PWM is suitable for most applications.

Sharp new LED ceiling lights will hit Japanese market

Sharp’s new models of Led ceiling lights enable to come in an extremely thin design - measuring a mere 43mm at the thickest point, going all the way down to 8mm at the thinnest.

www.ledlightsliving.com

Out of the six models, three of them - the DL-C501V/C301V/C302V, will enable one to rely on a remote control to change the color of the white light courtesy of the Adjustable Color function, not to mention being able to adjust its brightness level as well.

In a nutshell, you get 110 different levels of color and brightness in order to suit a particular mood or time of day. Having a heart for the environment as well, LED lights will help lower energy consumption by up to 65%.

LED component assembly benefits from SMT processes

Recent growth in LED technology and solid-state Lighting has provided the electronics manufacturing industry with viable solutions for its addition into today’s electronic devices. LEDs have become an alternative light source to conventional incandescent and fluorescent bulbs. The electronics manufacturing industry sees the greatest benefits from the small size and lower power consumption of today’s LEDs.

There also is the recent trend to use “green technology” in consumer and commercial electronics. LED components offer high brightness and power efficiency, as well as lower carbon emissions than traditional lighting technologies. This aspect has made Led lighting popular with government organizations, which are now installing led lighting in public places and government offices worldwide.

When used for illumination purposes, LEDs are more cost-effective than traditional lighting sources. Thus, the global LED component market is witnessing an increasing demand. As a result, companies in the surface-mount technology (SMT) industry are expanding their manufacturing capabilities to meet this demand. High brightness LED components currently are experiencing high growth as the backlighting application in TVs is shifting from traditional CCFL technology to LEDs. The range of new and potential applications for LEDs in electronics is practically endless.

 

 

In order for electronics manufacturers to get these LEDs into their products, they must use one of two methods: hand assembly or automated assembly. Hand assembly is where skilled technicians carefully place individual LED components onto circuit boards using specialized tooling. This is a long, tedious process that can slow the production rates of electronic devices and tie up major labor resources.

On the other hand, automated assembly uses the company’s existing SMT equipment to quickly and efficiently place thousands of LED components every hour. Most SMT equipment is capable of placing multiple components on a circuit board at one time, increasing the overall production rates while decreasing labor costs. Obviously, the goal of a high-volume electronics manufacturing company would be to transition assembly into automated production.

http://www.ledlightsliving.com/164ft-blue-led-neon-flex-p-153.html

Pick and place

The principle of using vacuum pressure and precision nozzles to enable component placement is repeated in every type of SMT equipment. There are five distinct stages of the pick-and-place process:

Picking: components are withdrawn from a feeder or tray by a vacuum nozzle

Holding: components are steadied for rapid movement while the machine detects proper alignment

Transport: components are transferred from the picking location to the PCB for assembly

Placement: components are lowered to their specific location on the circuit board

Release: components are released by the nozzle, which returns to the picking area to restart the process

No SMT equipment can place components accurately or run efficiently without quality nozzles and feeders, which are at the core of the pick-and-place process. If the machine is either unable to pick parts consistently or hold on to the components during the transport from feeder to PCB, defects will result. An increase in defects means a decrease in production, costing the company more money over a short period of time. Proper feeder and nozzle selection is critical, especially with the current market growth and technological advancements in SMT equipment.

Nozzles are the first and last thing to touch all components placed, and they move tens of thousands of these parts every hour. With components sizes reaching microscopic proportions, nozzle manufacturers must strive to maintain precision tolerances and exact dimensions in their designs. These nozzles are required to hold the part during transport to the board while the machine is moving and/or rotating at high speeds. providers must use this technology to get LED components into their customer’s products.

 

 

EMS providers

Debron Industrial Electronics, Inc. is a leading electronics manufacturing service (EMS) provider specializing in high-technology electronic assemblies, printed circuit board assemblies, electronic wiring, cable assemblies and box build. Mark Hoch, SMTA Certified Process Engineer for Debron, said “We are a contract manufacturer that caters to several customers specializing in cutting-edge LED technologies. They rely on our expertise to develop, document, implement and sustain their manufacturing processes.” When one of its customers needed a product that required the placement of LED components in its design, Debron decided to move forward with the automated assembly process.

Since making the transition, Debron has helped several of its customers to fully automate the production of products that previously had been assembled by hand. The company was able to do this by creating custom pick-and-place trays for LEDs that were available only in bulk for hand assembly. Debron also has been working with tooling companies such as Count On Tools, Inc. to develop custom pick-and-place nozzles that enable LEDs to be picked, vision centered and placed with high-speed, automated SMT assembly equipment. Streamlining the automated placement process has allowed Debron to free needed manpower to use in other areas of the assembly process.

As with any new project, there are some challenges associated with the placement of LED components in the SMT production environment. It is the goal of the EMS provider to overcome each of these obstacles to cut production costs and provide quality product to its customers and their end users. Some of the major challenges that EMS companies face when trying to place LED components in SMT production include:

1. Component handling in the feeder

During the picking process, LED components are withdrawn from the feeder by a vacuum nozzle. SMT technicians must ensure that the LED components are correctly positioned in the feeder pocket to guarantee that pick-up is achieved and that the LED is properly handled during the transport stages. “Slop in the pocket” may require nozzle centering during the picking process while excessively fast advancements of the feeder may skew the part in the pocket, preventing component pick-up.

2. Component handling on the nozzle and proper nozzle selection

Some LEDs, such as those from Cree, require special handling operations to prevent damage to the optical lens. They must avoid placing mechanical stress on the LED lens by not touching the optical surface during the component picking or placement processes. This eliminates the possibility of degraded performance from the LED after the circuit board is assembled. Proper nozzle selection also is important for the transport and placement processes. Not only does the SMT nozzle have to pick the component, it also must move it to the board and accurately place it. Most LED suppliers work directly with nozzle and tooling manufacturers, like Count On Tools, to develop nozzle designs that meet their individual process requirements.

3. LED sensitivity

The fragile optical surface is not the only issue with the use of LEDs in SMT production. Early LED designs were very temperature-sensitive, forcing assembly using unconventional methods, such as hand assembly. LEDs often were bonded to heat dissipative substrates using conductive epoxies or low-temperature solders. This required special assembly processes that lengthened the manufacturing process, increasing product build costs.

 

 

4. Scaling up to high-volume production

As LEDs become more robust, assembly via means of more conventional assembly processes such as automated SMT equipment allows EMS companies like Debron to focus on other challenges such as repeatable part picking and vision centering, as well as effectively increasing throughput and minimizing defects. Repeatable performance is the major challenge with scaling up to high-volume production. EMS providers must strive to maintain a high level of performance to keep their production on track to meet customer demands. This requires fine tuning the assembly process.

As with any problems in a production environment, there is always a solution. By capitalizing on its current knowledge of SMT production and partnerships with quality suppliers, Debron was able to overcome most of the challenges associated with this process. Debron developed custom trays for the LED components to allow for more accurate picking and transport processes while eliminating issues with component handling in the feeder. It also worked with its equipment manufacturers and custom-tooling manufacturers such as Count On Tools, Inc. to develop custom SMT pick-and-place nozzles that increase LED/nozzle compatibility, allowing for greater placement accuracy and increased throughput.

Due to the partnership with Count On Tools, Inc., Debron was able to fine tune its automated assembly process and scale up to high-volume production of LEDs. Using the custom nozzle that it purchased from Count On Tools, Inc., Debron was able to reduce LED fallout to 2.3 percent. Defect rates dropped significantly and first pass yields increased steadily up to 99.4 percent.

Summary

In conclusion, the latest LED technology opens up wide areas for new applications, new technical possibilities and reduced costs in both the SMT and electronics manufacturing industries. Today, many companies are crossing traditional business boundaries and streaming into the LED lighting market. This, in turn, has created a large demand for LED use in general markets and not the traditional niche applications. By partnering with component manufacturers and nozzle/tooling suppliers, EMS companies like Debron can guarantee success by lighting the way for customers seeking LEDs in their SMT production.

Philips Lumec Introduces New LED-based Roadway Light

Philips Lumec Wednesday unvei Led its newest product, the RoadStar?, a state-of-the-art LED luminaire designed specifically for large area, street, and roadway Lighting applications. The RoadStar? has the potential to reduce by 50% the amount of electricity a city/state/country uses for street and roadway lighting.

http://www.ledlightsliving.com/

Philips Lumec has successfully designed and implemented solid state lighting solutions for projects in North America. The new RoadStarTM luminaire uses LUXEON? Rebel power LEDs, saving approximately 50% on energy consumption compared with traditional HID CobraHeads.

The RoadStar? LED luminaire brings to the table major social benefits, and in its industry, it’s the first of its kind. Besides its myriad benefits, it has the ability to replace existing energy hungry HID (High Intensity Discharge) CobraHead lighting fixtures without the need to change a city’s lighting infrastructure. Installers simply swap one for the other and instantly reap the benefits of this sustainable technology.

http://www.ledlightsliving.com/led-solar-lights-c-93.html

Philips Lumec’s patented LED technology provides over 70,000 hours of operational life and the RoadStar? also contributes to the environmental cause by considerably reducing the need to constantly replace burnt out lamps. This reduces the need to deploy maintenance trucks and personnel by up to 7 times, saving any city money, and lowering their carbon emissions at the same time.

The RoadStar will be launched simultaneously on September 13th 2009; in the U.S, at the APWA's 2009 International Public Works Congress and Exposition in Columbus, OH, and in Canada at the AIMQ (Association des Ingénieurs Municipaux du Québec/Municipal Engineers Association of Quebec) in Trois-Rivières.

Best LED Grow Lights Improves Indoor Gardening

Best LED Grow Lights Improves Indoor Gardening

Indoor Gardening

Most people live in areas of the world that are either not warm enough, or do not receive enough sunlight on a daily basis to grow crops year-round outdoors. Over time home-sites have also become smaller and smaller, reducing the area most homeowners have for an outdoor garden. As a result most people are forced to purchase hormone-grown, pesticide-loaded fruits and vegetables from the grocery store, that taste less and less like fruit each year. The only option most people have to sustain their families year-round with organically-grown, vitamin-rich food, is by starting their own indoor garden. That is where LED Grow Lights are the perfect solution, as plants require a light source other than the sun if they are to grow indoors.

 

Best LED Grow Lights

LED Grow Lights are the latest form of indoor plant lights, offering their users a green and energy-efficient alternative to HID (High Intensity Discharge) lighting. Just as our bodies require specific nutrients to stay strong and healthy, plants require specific ratios and colors of light in order to properly photosynthesize. Unlike HID lights which emit a full-spectrum white light (much of which is unused by plants), LED's emit narrow wavelengths of light that can be combined to simulate the specific ratios and spectra that plants use most efficiently for photosynthesis. By arranging LED's of the proper wavelengths and ratios, LED Grow Lights are able to deliver up to 100% usable light for plant growth! LED Growlights also operate hundreds of degrees cooler than HID bulbs, making them a much better alternative for indoor gardens. With the use of LED Grow Lights one can reduce their power bill by up to 70%, while virtually eliminating the need for ventilation and A/C. LED GrowLights also eliminate mercury-filled HID bulb replacements, and contain no harmful or un-recyclable materials.