LED Lighting: Its future in safety applications is bright
January 1, 2006
The incandescent bulb was once the preferred way to light a flashlight. But in the past 15 to 20 years, LEDs have steadily evolved from the VCR and EQ gauge to an integral part of safety lighting in todayâ€™s industrial, safety and manufacturing settings. Their safety characteristics, extreme battery efficiency, toughness, versatility and brilliant collimated beams have earned them high marks among safety professionals worldwide.
Ken Scofield of the Blue Springs, Mississippi, Fire Department says, â€œDuring a primary search, my partnerâ€™s light only went a foot or so in front of him, and it had a lot of back scatter, to the point that visibility was just as bad with his light on as it was without. After he saw mine cut through the smoke, he shut his off and put his back in his pocket.â€
â€œWe were absolutely amazed that through thick, dark smoke, the LEDâ€™s beam shot several feet ahead of us, illuminating not only the objects ahead of us, but we could even make out some of the details like patterns on the wallpaper and the corner of the chair leg, through the smoke.â€
At the Mississippi Stateâ€™s Summer Fire School, firefighters throughout the state in hot, smoky, steamy environments used LED lights that outperformed other styles of flashlights. â€œSignificantly less back scatter, further penetration in the smoke, and the ability to make out some detail in the smoke. Every time. Without exception,â€ adds Scofield.
What is an LED?An LED (Light Emitting Diode) is a solid plastic bulb embedded with a semiconductor that emits photons or light particles when excited by an electrical current. White LEDs are the staple in flashlight technology, but currently just about any solid colored LED (green, red, blue, yellow, purple, white, etc.) can be created.
White LEDs are made with a single blue LED chip that has been covered with a special material called phosphor to alter the color of the emitted light.
The overall result is a super bright LED that produces a white to bluish-white light. Generally speaking, white LEDs are exactly the same as blue LEDs. They have the same voltage and current requirements, because both white and blue use an almost identical chip.
LED qualitiesLEDs are increasingly being used as an alternative to incandescent bulbs. There are a number of reasons for this. Here are just a few:
- LEDs have up to 5,000 times more life than an incandescent bulb.
- LEDs are ideal for extended operation because of their low power requirements.
- LEDs use about one-tenth the power of incandescent bulbs and are up to 90 percent more efficient than both fluorescent and neon lamps of similar strength.
- LEDs donâ€™t have a filament like incandescent bulbs so they canâ€™t burn out and are shock-resistant.
The normal working lifetime of an LED device, including the bulb, is more than ten years, giving them a distinct advantage over the abrupt burnout of incandescent bulbs.
Brighter and brighterWhile LEDs havenâ€™t yet eclipsed incandescent bulbs from a brilliance and power standpoint, the technology has a rather brief history. If Mooreâ€™s Law prevails, then the power of LEDs will double every 18 months.
â€œThe inherent advantages that LEDs have over common incandescent bulbs (long life, shock resistance, full color light) make them a natural choice as a replacement. Just a couple of years ago we saw LEDs appear on the market that could produce ten times the light of the previous generation of LEDs,â€ says Doug Pribis, author and owner of Flashlightreviews.com.
Incandescent bulbs are cheap to buy but inefficient to run, generating a range of about 16 lumens per watt for a domestic tungsten bulb to 22 lumens per watt for halogen bulbs. LEDs are tougher and much more efficient than common incandescents, with the average commercial LED generating about 32 lumens per watt.
More does not mean brighterIn the past, to get a usable bright light, multiple LEDs needed to be gathered in an array, but even then the light was hazy and diffused. The latest LED lightsâ€™ power have eclipsed the models produced only a couple of years ago and offer more consistent color in a very small package. Their beams can now be focused and brilliant with the help of single 3 Watt and 1 Watt LEDs and specially engineered reflectors. They can now generate as much as 45 lumens per watt in white, making them equal to about 10 to 20+ ultra-bright white 5mm LEDs, occupying the same or less space.
Recent technological advances such as Recoil LEDâ„¢ offer a collimated beam comparable to a regular flashlight, ushering them into the professional marketplace as viable alternatives to incandescent bulbs. The technology works like a handheld lighthouse by mounting an LED on a crossbar that shines backward into a parabolic reflector to gather 100 percent of the generated light.
â€œI expect that LED lighting technology will continue to grow at an exponential rate. I would not be surprised if within the next several decades, most of the man-made light we encounter in our lives is produced by energy-efficient, full-spectrum solid-state LED â€˜bulbs.â€™ Itâ€™s only a matter of time until we see LED bulbs producing 10, 100 and 1,000 watts equivalent of light,â€ adds Pribis.
LEDs â€” a little dollop of plastic coupled with the semiconductorâ€™s endurance, efficiency and power â€” will no doubt save many lives and lots of money in the coming years.