Are there LED headlights?


#1

Some appear to be. Or am I mistaking HID headlights?
Each of our vehicles carries a spare headlight bulb.
(Naturally a headlight burns out when departing at 1 a.m. to a mountain hospital on a route with lots of deer.)


#2

Acura offers that, as one example. For a picture, see:

http://www.acura.com/Features.aspx?model=RLX&modelYear=2016&context=Exterior#jewel_eye_led_headlights


#3

Search on google for “LED headlight” and you will find lots of places that sell LED replacements for most cars. The OEM bulbs tend to be halogen or incandescent, but some are LED.

From the internet: “LED headlights, currently a technology for pricey luxury cars, are starting to enter the mass market. By 2020, LED headlights will account for 20 percent of headlights produced worldwide – up from roughly 2 percent this year, according to a market projection by Osram, a leading supplier of automotive lighting components.”


#4

I wouldn’t buy one as a replacement for my regular bulb, the geometry can be wrong. But makers are switching to them, makes sense, less power used.


#5

LED headlights were finally approved in the U.S. and are on some current cars. I prefer incandescent (quartz-halogen), but soon all new cars will have LEDs.

LEDs are far richer around the 400 nanometer wavelength (blue-purple) and drop off rapidly above about 650 nanometers (orange-red), whereas incandescent bulbs are far lower in the 400 range and far, far richer above 650. To my eyes, this gives LEDs a much “harder” light, incandescent being much “warmer”.

I realize it’s just a preference. But that’s mine.


#6

Unlike incandescent bulbs which give light off in a full 360 in all directions, LEDs emit light from a junction between two semiconductors. It tends to have a very narrow angle. LED light bulbs use an array of LEDs pointed in different directions to provide even lighting in a space.

It would be very difficult to design a LED replacement bulb to work where an incandescent bulb was designed for. You would need a completely new headlight assembly to get the proper pattern. LEDs would make very good headlights and it probably wont be long before they become standard on cars.

I would prioritize brake lights first as LEDs light up almost a quarter of a second quicker than incandescents. That would help reduce rear end collisions, maybe. A quarter of a second is 22’ at 60 mph.


#7

As an Operation Lifesaver presenter riding in Amtrak locomotives videoing grade crossing behaviors between Santa Barbara and San Diego, traffic signals next to grade crossings would cycle and go into a four-way-flash mode.

At the beginning of each one-second flash, 12-inch red LED traffic signalamps would appear to “strobe” (one bright blink) and then be at normal brightness.

Is this because we are accustomed to incandescent filaments starting dim and heating up to full brightness in 1/4-second, whereas LED lamps acheive full brightness instantly?
Interesting optical illusion.


#8

Keith, I agree with the prioritization of brake lights, for exactly the reason you mentioned. I’ve actually seen LED brakelights on many cars these past years. It took a few years for manufacturers to get them approved as headlights.


#9

Geez, I hate the LED brakelights. They “strobe” on, vs come on more gradually (as in a few milliseconds vs instantaneous). Now, the problem with that is, the only lights (until VERY recently) that “strobe” are emergency vehicle lights! You “notice” them, sure, but they are somewhat shocking and disruptive.

Anyways, where do you get that “1/4 second” figure from? That’s “forever” for a light. Old-style light bulbs are incandescents, and there’s no way it takes 0.25 sec from “flipping the switch” to a lit room. (Maybe it takes 0.25 sec to reach FULL brightness, but rest assured, they are producing noticeable light in less than 0.1 secs, or you’d notice the lag).


#10

If you see an LED side by side with an incandescent, you notice the lag. A quarter of a second is not very long, certainly not forever.


#11

^ Yes. Compared side-by-side filaments take noticeably longer to attain full brightness.
(I plan to put our LED holiday lights on a full-wave bridge rectifier with filtered DC to eliminate their strobing. Wonder how much brighter they will appear?


#12
(I plan to put our LED holiday lights on a full-wave bridge rectifier with filtered DC to eliminate their strobing.

Be sure to let us know how this works out.


#13

I bought LED Christmas lights a couple of years ago and they work beautifully. I will never use the old type holiday lights again. LED lights are here to stay. I never have seen this strobing effect but I am getting older.


#14

If there is no rectification, the LED is ON for only half of the 60 Hz AC cycle.
If you scan your vision from side to side, - - - - - - - - - - may be noticeable.
If the AC has been changed to DC, it would appear --------------.
A filter capacitor would discharge and fill in the small gaps when the AC current is at Zero.

One problem may be that half of the LEDs may illuminute on the Positive side of the AC cycle and the other half on the Negative side of the cycle.
So the DC may cause half of the LEDs to not light. (The string’s wiring would need to be changed.)


#15

I bought LED Christmas lights for our tree and my wife couldn’t stand them, made me take them back off and put incandescent lights back on. She said the light was too intense and too cold, it just didn’t look right. So now I use the LED strings for the outdoor display.


#16

^ Yes, the overall appearance of an LED string is bluish. LEDs have the richest Blue and Red colors. We mix LEDs and warm incandescent lights. The incandescent lamps also fill in for the 60 Hz blinking of the LEDs.
Bet LED string blinking in England is even more noticeable. The UK is 50 Hz.


#17

“One problem may be that half of the LEDs may illuminute on the Positive side of the AC cycle and the other half on the Negative side of the cycle.”

All the Xmas lights I’ve seen operate full wave on each light.
Bridge rectifier; no filtering.
I’ve tested LEDs operating 60Hz half wave and the strobing is really obvious.


#18

^ Oh! Thank you. Did not know they were sophisticated enough to have rectifiers.
Ours are cheap ones from years earlier. Or the full-wave rectifiers are not working.
So all I need is filtering capacitors on new LED strings?


#19

Can’t say in without hacking in an individual case.
This has been off topic long enough.


#20

I agree with keith, the LEDs are noticeably faster. I can still remember the first time I saw one many years ago and it was shocking at the time. It still has a slight effect on me when an LED brake light illuminates on a car directly in front of me (at a stop light for example) vs a standard incandescent. They are now becoming ubiquitous and so not quite so alarming to see.

Here’s an article that supports keith’s statement regarding 1/4sec for standard incandescent to 90% output…

https://deepblue.lib.umich.edu/bitstream/handle/2027.42/64045/84696.pdf;jsessionid=05953B2E17837E95B65E7C9CEF24F6AA?sequence=1