The next time you're stopped at a traffic light, look closely. Those just might be LEDs in place of your father's tried and true incandescent bulbs. Or if you're driving behind a semi, the red brakelights are probably LEDs.
LEDs have been making inroads into territory traditionally held by incandescent and fluorescent bulbs, such as general-purpose lighting. They're also increasingly used extensively in good old industrial applications; as replacements for incandescent bulbs on panel indicator lights, in scanners as light sources, and in backlighting applications where they displace more costly and heat-producing electroluminescent bulbs.
Here's a brief look at some LED applications that are gaining ground, as well as some novel approaches to traditional lighting setups.
On threads of light
Lumitex Inc., Strongsville, Ohio, manufactures fiber-optic backlighting panels. One or more LEDs produce enough light to diffuse over the panel area. Fiber-optic panels are an alternative to electroluminescent types and LED arrays and light pipes which direct light to some desired area. Plus, the fiber-optic panels, lit by LEDs, don't require an inverter to convert ac to dc voltage, reducing cost and consumed power.
Now, newer fiber-optic panels incorporate conductive pads for backlighting membrane switches. The pads are integrated into the switches for use in keypads, keyboards, and membrane switches. The light sources feature low-power consumption (10 to 25 mA), last up to 100,000 hr, have zero impact on the tactile feel of elastomeric keys, and can backlight a larger area than surface-mount LEDs.
Conductive pads are printed on the underside of the fiber-optic panel and, when integrated with rubber keypads or membrane switch overlays, function as a switch. A conductive material on the pads is suspended above the traces on the PC board. Pressing a button, rubber keypad, or membrane switch deflects the conductive pad down on the PC board where it makes contact, closing the circuit.
This approach lets switches be totally encapsulated with an adhesive layer around the PC board traces to seal out contaminants that can cause premature switch failure.
Lumitex Inc., (800) 969-5483, www.lumitex.com
Any color but black
Ford's GloCar concept vehicle can turn any color according to the environment around it or the driver's preference. The car uses LED lights which shine onto translucent plastic panels to change body-panel colors and intensity.
Better visibility improves safety. For instance, increased visibility is said to cut down on nighttime accidents at intersections, where purportedly 60% of all accidents take place. Sensors on the car detect when a car is too close, increasing the brightness and signaling drivers to keep their distance. The fact that the car is lit up from all angles not just headlights and taillights adds to its visibility. The car could also simplify manufacturing by eliminating the need for vehicle paint. Plus, the need to make only one version of a vehicle would speed production. Of course for now, it's only a concept. But some day soon you might see a car whose color changes right before your eyes.One way engineers can keep up with new lighting technologies is through companies like Inventables. Based in Chicago, they offer samples of the latest engineering materials and technologies to engineers and industrial designers including LEDs and other up-and-coming lighting technologies.
Inventables, (773) 697-0130, www.inventables.com
LEDs light the way
LEDs are beginning to displace regular-old incandescent bulbs in ordinary room lighting. Case in point; the Infinite1 LED lamp from Bivar Opto, Irvine, Calif., is meant as a direct replacement for incandescent spot and flood lamps. The lamps sport an Edison-base housing assembly directly interchangeable with industry-standard PAR-style spots and floods. 39 LEDs arranged in a grid-array pattern generate light comparable to that of an incandescent spot or flood lamp.
The series features a multioptic lens that rotates 90° letting a single unit provide both flood and spot output. Lamps are available in amber, red, yellow, green, blue, white, and RGB for a blend of color outputs. Power consumption is less than 3 W at 110 Vac.
Another LED lamp has hit the market as a replacement for popular halogen lighting. LED lamps from Mule Lighting, Providence, R.I., are drop-in replacements for MR-16 style halogen fixtures. The big plus is the lamps produce as much light as their halogen cousins without the associated heat. They operate on voltages from 6 to 24 V, ac or dc, and consume only 1.8 W.
Bivar Opto, (949) 951-8808, www.bivar.com
Mule Lighting Inc., (800) 556-7690, www.mulelighting.com
Brighter LEDs are also used in applications other than lighting. For instance, Wintriss Engineering Corp., San Diego, touts a linear LED light source using hyper-bright 5-W LEDs. The lights are aimed at quality-control applications in paper, web printing, industrial fabrics and coatings, and other inspection applications.
The company's LED Ranger-Series puts out 100,000 lux at a distance of 4 in. and is said to cost less than high-pressure sodium or fiber-optic light lines. They're available in 20-in. segments that can be joined end-to-end with no illumination gaps and come in red, blue, white, green, and infrared.
Wintriss Engineering Corp., (800) 550-7300, www.weco.com
Walls of light
LED modules from Osram Opto, Regensburg, Germany, light prototypes of flexible wall elements developed by the Department of Construction Realisation at the Technical University of Munich in cooperation with industrial partners.
Glass-wall elements, sandblasted or coated on one side, anchor in a frame construction hidden from view. Sandwiched in the space between the panels at the bottom are several LED modules about a foot and a half long and less than a quarter-inch high. The modules can produce a range of colors from the basic red, green, and blue.
Osram Opto, (978) 777-1900, www.osram.com
LEDs and controls continue to make headway in the lighting market. Here's a look at the best and brightest.