With the rapidly evolving world of LED lighting, these small, amazing, solid state lights which have been around since the early 1960’s are being found in more and more products and places, some are quite bizarre.
Previous to the commercial advent of LED’s which were powerful enough to be used for area lighting, there were plenty of LED’s in our lives but they were mostly unknown and just taken for granted. The first mainstream applications were for indicator lights in such items as audio and video equipment, appliances, tools, toys and other simple applications that required some sort of light indicating some state of operation. Digital readout alpha numeric screens were also among the first applications. Needless to say, those LED uses were a form of lighting which most of the population paid little attention to and likely did not know (or care) that they were LED’s. Those indicator light applications were really quite a boon to industry, and consumers as well, as the LED’s far outlasted the incandescent and neon bulbs which were previously used, and the LED did not need an additional colored lens or cover of some sort to color the light. The first LED’s produced only low end red frequencies of the spectrum. It wasn’t until 1994 that the first high brightness blue LED’s were produced. In 2014, the Nobel prize in physics was awarded for that development. Later developments (but before 2014) of phosphor coatings partially converted the blue light to red and green frequencies to produce white light. Initially the first colored LED’s were only red but with the advent of white light, the colors were created by the resin that made up the enclosure/lens. Eventually, LED’s were developed which emitted colored light, created by differing semiconductor elements, and allowed the enclosure/lens to be clear. In addition to the smaller sizes, brighter output, color availability, hugely extended life and power consumption reduction, there is the issue of heat. As much as 95% of energy consumption in incandescent lights of all sorts produces heat. Although, there is a small amount of heat produced buy LED’s, that heat output is quite small and well controlled when compared to any and all incandescent lighting.
One of the initial successful applications of LED’s for small area lighting was in the form of flashlights which, initially were fairy impressive, as a small LED flashlight might well be able to out-shine most of its incandescent bulb equipped predecessors with a slightly brighter and definitely higher color temperature light (in Kelvin) than an incandescent flashlight. Those initial LED flashlights, which generally contained numerous LED’s, now pale in comparison to recent LED flashlights which are advertised as having lumen output as high as 10,000+ Lumens. That’s incredible! I recently purchased a “tactical” LED flashlight that is rated at 8,000 Lumens and, wow, what a light – and it only has one tiny LED array chip! One which you don’t dare look directly into when lit. The brightness is even played up as a defensive weapon against an attacker, and can be activated in a blinding strobing mode. The light also zooms and dims to two levels and flashes SOS. The entire package is nicely designed, built like a tank and is half the size or smaller than previous standard double D-cell flashlights. I have a couple incandescent flashlights which were (previously) used by the military and first responders and, even while burning xenon and krypton bulbs, the beam of the 8,000 Lumen LED light pretty much drowns out the light from those flashlights. It also will last many times longer and can withstand the sort of shock that no incandescent bulb could sustain without going dark. I also tried an LED headlight – you know, those contraptions that are worn on your head. This one was rated at 12,000 Lumens! Almost gives you whiplash when you turn it on. Bad humor but incredible light!
The mention of a headlight would normally refer to the front lights of a vehicle, which have changed tremendously with the introduction of high output LED’s. Not only has the longevity and intensity of the light increased but the fact that the potential applications are able to easily be quite various, thus the greater latitude that designers and engineers have in creating stylish headlights, compared to the old round, rectangular, or square automotive headlights of the past. The biggest reason for those shapes was that prior to 1984, here in the U.S., sealed beam headlights were an automotive requirement and round and square were the most economical and universal fitment method of producing them. In fact, the laws changed over the years, eventually allowing two headlights per side and eventually rectangular/square shapes to be used. These shapes were literally mandated by federal law. In 1984 the law changed and, for the first time, the headlights were allowed to be modular and contain “bulbs” which could be changed, instead of having to replace the entire sealed beam headlight unit. That allowed the introduction of vehicle front end styling which was never before allowable. Now, the use of LED lights has definitely changed the design potential of vehicles. In the newer vehicles, all the lights, inside and out, are LED; from the lights in the dash to courtesy lights to the outside driving and marker lights. There are now lights in places there never were before; in places such as under the car at door openings, for courtesy lamps, where a designer never would have trusted an incandescent light in the past. Yup, the advent of LED’s has definitely changed design in the automotive world.
The LED flashlights and headlights have something in common with modern LED area lighting, in that Cree, a major player in the residential and commercial LED market, supplies the raw LED’s for a huge percentage of the applications. Those two examples of everyday things that have been vastly changed and improved by LED technology are just a couple applications. There are some leading edge ideas and some completely bizarre applications that are being tried and I’m sure the future will reveal things unthought-of at this time. At another point in time we will probably explore some of those other applications.