Blue Headlight Bulbs
Aren't those new blue headlights major cool? You know, those bulbs that turn your bike's headlights blue. Yeah, they look different all right. But are they all they're cracked up to be? Continuing in our series of things mythical and disengenuous in the powersports industry, we come now to blue headlights. Like most that passes for "cool", there's a lot going on here, so hang on tight.
The Headlight's Evolution
The Tungsten-Argon Headlight
One of the earliest headlight technologies to emerge after the acetylene lamp days of the 1920s and 1930s was the tungsten-argon headlight. The tungsten-argon headlight was based on a large glass housing called a sealed beam, thus it was known early on as the sealed beam headlight. At the center of this glass enclosure was a heat-resistant tungsten thread (filament). This special wire was heated by passing electricity through it, until it got white-hot, or became "incandescent." In early units, a vacuum sealed inside allowed the filament to glow very bright yet not be consumed. Later examples used Argon gas instead, to slow filament deterioration. The tungsten-argon headlight has a big drawback however, and that is its low efficiency. The design produces more heat than light, so the electrical energy is mostly wasted. This inefficiency makes tungsten-argon headlights look very yellow, because the total light output is low, and the yellow parts of the light spectrum therefore show visibly. The output also gets worse with age, because the filament is always eroding, and metal from the filament is slowly deposited onto the headlightís glass, the deposit increasing and reducing the lightís output all the while.
The Tungsten-Halogen Headlight
During the late 1970s the tungsten-argon headlight was replaced with a better design, the tungsten-halogen. Like its predecessor, the tungsten-halogen design also uses a tungsten filament. However, in the halogen headlight, this filament has less resistance, causing more current to flow through it, heating it up still more, producing a brighter light. Also, this filament is enclosed inside a replaceable bulb made of quartz, so chosen because glass would melt in this design, being so close to the extra-hot filament. (Later versions used less expensive high temp glass, yet the design is still often called the quartz-halogen.) The gas inside the bulb is not Argon but a gas from the halogen family, often iodine. The iodine gas combines with the tungsten of the filament, permitting the dissipating filament'ís metal to redeposit itself from the glass back onto the filament, extending the filament's life and preventing the permanent clouding of the headlight. Combined with the higher current, this produces a brighter light, for a longer time. However, this is another inefficient design as the tungsten-halogen headlight gets its extra light mostly from extra heat, due to its higher current usage. In fact, older bikes factory-equipped with tungsten-argon headlights can be badly taxed electrically when upgraded to halogen bulbs. And not to be overlooked, a halogen bulb runs so hot it can reach over 450o F., so hot in fact that merely handling the bulb can deposit body oils onto the glass which may cause heat to reflect back onto the filament and cause it to fail. No other headlight design is burdened with such a prohibition.
The Projector Beam Headlight
In the early 1990s headlight development could be characterized as focused on focusing. More efficient throwing of the light forward turned ordinary halogen headlights into brighter than ever lights, and at the same time gave designers more freedom in headlight placement in motorcycle bodywork because these more efficient lights could be manufactured smaller. The projector beam headlight became the standard in powersports and in some ways remains so as of this revision.
The High Intensity Discharge (HID) Headlight
In the late 1990s the first non-incandescent, high intensity discharge (HID) headlight emerged. The HID addressed the problem of the incandescent headlight's low efficiency, by doing away with incandescence altogether. The HID headlight was adapted from industrial large-area lighting, such as the lighting in sports stadiums. Unlike other headlights, the HID has no filament. It produces light by throwing a high-voltage arc into a special gas, and the gas reacts to this jolt by producing light, much the way a flourescent light works. Because it'ís not an incandescent design, however, the HIDí's electrical efficiency (and light output) is more than three times that of incandescent headlights. With no glowing filament, the headlight operates much cooler and failures are much less frequent. It's a brighter, more durable, longer-lasting light.
However, though found on mwny of today's cars, a few motorcycles, and avalable in aftermarket form, the HID is a much more espenwive headlight. The adaptation of HID technology to vehicle use required solving several technical problems, all of which added to the cost of manufacturing. One such problem was warm-up. Stadium HIDs take 5~10 minutes to warm up, an unacceptable situation on a motor vehicle. To compensate, sophisticated special start-up circuitry is used in HID headlights, and aa result, unlike stadium lights motor vehicle HIDs reach 75% of full intensity in just a few seconds.
In addition, in the early days of HID use a handful of issues kept it from being readily accepted by major vehicle manufacturers, though these objections were eventually overcome. For one, the HID had at first a very sharply defined light envelope. Unlike the tungsten-halogen'ís soft light edges, the HIDí's beam left a sharp line between what was illuminated and what is not. The result was startling to the first-time user. Objects dramatically appeared and disappeared at the edge of the beam as the vehicle traversed irregularities in the roadway, producing an uneasy feeling. It took some getting used to until redesigns in the headlight's lenses corrected for this. A more obvious effect is the HID'ís seeming blue cast. The usual yellow color typically produced by other headlights is almost totally absent in the HID. As a result, HID light appears slightly blue alongside other headlights. (Blue and yellow are color opposites. When yellow is removed from the color spectrum within white light, blue is enhanced.) There was even some talk initially that this blue characteristic might be harmful to night vision, as some supposed that it affected the eye's natural ability to protect itself from glare by contracting its pupils, but this seems now to have been an unwarranted concern.
But there are some bad blue headlights out there. The aftermarket is absolutely teeming with blue headlight bulbs today, most of them HID headlight emulators. Copy-cats. These "cool blue" fake HID lights are merely tungsten-halogen bulbs with a blue tint added, producing a bluish headlight. Unfortunately, blue is the shortest light wavelength, and as a result this blue light dissipates quickly, producing more glare from fog, rain, and snow. For this and other reasons, non-white headlights are illegal for road use in the U.S., Canada, and in other countries. Another version of the "blue" headlight bulb has a gold color filter, which blocks the yellow in the bulb's light, resulting in a whiter output. The reduction of the halogen's yellow output brings as a byproduct a slightly blue cast, just as the yellow's inherent absence in the HID headlight makes its color slightly blue. However, the two systems are completely different and get their blue byproduct from different sources, and unlike the HID, the overall light from this &qiot;ultra-white&qiot; tungsten-halogen bulb is sharply reduced. The major color in the incandescent headlightí's light remember is yellow. Therefore, with the yellow spectrum blocked, less light reaches the road, even though it may appear whiter. These lower-output bulbs are, surprisingly, legal because they conform to the government regulations specifying white light, despite output is that is actually less bright than that from standard tungsten-halogen headlights.
Going into 2013 the latest thing to emerge was the LED headlight. Following a few years after becoming standard in tailights, the light emitting diode headlight seems to promise many of the benefits of HID with none of its drawbacks. That is, a bright white light and no filament, but unlike HID, very low power consumption, cost efficiency, and a technology that is far less complicated. One significant benefit is the headlight has the least amount of light loss of any design. That is, very little light is produced anywhere but straight ahead. And with a projected 50-100 thousand hour life, the LED appears to be the all-round best headlight for today.
To summarize, there are three kinds of so-called "blue" headlight systems. The HID, which started the blue craze, is the real McCoy. It has a legitimate, slightly blue (actually very faint violet) cast due to its otherworldy whiteness and our being used to yellowish light, and is therefore not actually a blue headlight, but extremely white and bright. HIDs are pretty common on cars now, and can be found on one or two motorcycles as original equipment as well. The second type, the so-called "cool blue" headlight bulb, is an HID fake, and that's all. It is illegal in all of the Western world because it is in fact a colored headlight. Finally, the third type, the much-touted "super white" headlight bulb, while not an HID fake, is still an unwise attempt to brighten the headlight by removing its yellow range. Unfortunately, in the process, though the light is whitened to the point of having a slight blueness, the output is actually weakened. Though legal, this third category of headlight bulb isn't really any better but actually worse, than an older headlight type. Lastly, having been introduced in just the past year or so as of this revision, the LED headlight appears poised to take over as the state of the art in headlight technology. Bright, efficient, cool-running, and stylish, the LED preaently has no equal in production street application.