Why are pathetic LEDs still blinding?

[strantor]

This is just my observation and I'm curious if anyone else has noticed that "bright" or "super bright" LEDs like those in cheap flashlights, cheap aftermarket LED headlights, and sometimes even just status LEDs on different circuit boards or appliances can be blinding to look at, while providing an unintuitively disappointing amount of illumination. I'm sure some of it has to do with the quality of the external optics associated with the LED (parabolic cone reflector in the case of flashlights and headlights) but I don't think that explains the whole phenomenon. If I take a LED and an incandescent bulb alone (no external optical devices to influence the result) that provide roughly equal illumination into a dark, both just bright enough to see where I'm going, the incandescent will be almost comfortable to look directly at, while the LED won't be. I don't think (not sure) that it has anything to do with wavelength either, because I have observed this with all kinds of LEDs. Red and cool white do seem the harshest to me, but even the warm white and other colors are just... unreasonably hard to look at.

 

[Reddinr]

It's the blue ones that get me. Designers really love the blue ones these days. I've put a spot of paint on a blue one on my streaming box/clock radio. I can still see it is on or off but it isn't the laser beam of death it once was. I think the worst ones are the ones with narrow focus. They are intense.

 

[homebrewed]

It's not the total light output, it's the fact that LEDs are more of a point source compared to the filament of an incandescent. This makes it easier, in an optical sense, to direct and collimate or focus them them. The ultimate example is a laser pointer. They may only put out a few milliwatts-worth of power but they will focus down to a very small spot on your retina, so the power per unit area will be very high.

Many LED flashlights have a warning on them to not look directly into their beam, for a good reason.

 

[mac1911]

All I know is LED work lights seem to increase shadow effect ? Like working under a dash board of a car, engine bay ectect.

 

[RJSakowski]

An incandescent light uses a filament and the light output is distributed along the entire filament. LED lights are closer to point sources. In order to have the same lumen output, the LED must have a brighter flux . An incandescent light is closer to a 360º distribution and a directed beam relies on the parabolic reflector to concentrate the light beam. An LED essentially emits light in a 120º cone and although reflectors or lenses are used the bulk of the light comes directly from the LED die itself.

 

[pontiac428]

All of the above. Plus, power is the area under the curve, and when the output is switched PWM, the result is much higher intensity for the same illumination level.

 

[jwmay]

Down with LEDs!!

That is all.

 

[Jake M]

I'm not a fan of LED lights. At least not for illumination purposes. I've pretty much adopted them as it's the way everything's going, it's what's available, and kinda better in every way except illumination. How's that for a sales pitch for a light bulb...

Colors are not right in LEDs except in certain situations. The lighting is so specific in the colors within it (not full spectrum) that it HAS to be way brighter than incandescent or natural lighting in order to get the same amount of "seeing". That ends up making it fatiguing. Shadows are always an issue due to more directionality from the light source and less from the fixture, more concentrated and directional.

The flash lights I'm positive are designed to look good when you're looking at them in an overlit store. I still have a couple of little mini-mag lights, and they're not near as clear as they used to be, but even those turds make a lot more comfortable light...

Lower "kelvins" kinda helps with all my gripes, to some degree. Not really an option in flashlights. Some LED lights are better than others. I've got a hunch they could be indistinguishable from incandescenet or natural lighting if we "wanted" them to badly enough, but it probably saves a few cents per chip if we keep 'em just crappy enough that people only grumble, and don't start an underground incandescent light bulb cartel...

 

[ozzie46]

This is just my observation and I'm curious if anyone else has noticed that "bright" or "super bright" LEDs like those in cheap flashlights, cheap aftermarket LED headlights, and sometimes even just status LEDs on different circuit boards or appliances can be blinding to look at, while providing an unintuitively disappointing amount of illumination. I'm sure some of it has to do with the quality of the external optics associated with the LED (parabolic cone reflector in the case of flashlights and headlights) but I don't think that explains the whole phenomenon. If I take a LED and an incandescent bulb alone (no external optical devices to influence the result) that provide roughly equal illumination into a dark, both just bright enough to see where I'm going, the incandescent will be almost comfortable to look directly at, while the LED won't be. I don't think (not sure) that it has anything to do with wavelength either, because I have observed this with all kinds of LEDs. Red and cool white do seem the harshest to me, but even the warm white other colors are just... unreasonably hard to look at.

At first glance I thought you were talking about car headlights. They blind me.

Ron

 

[MikeInOr]

An incandescent light uses a filament and the light output is distributed along the entire filament. LED lights are closer to point sources. In order to have the same lumen output, the LED must have a brighter flux . An incandescent light is closer to a 360º distribution and a directed beam relies on the parabolic reflector to concentrate the light beam. An LED essentially emits light in a 120º cone and although reflectors or lenses are used the bulk of the light comes directly from the LED die itself.

Any professional flash photographer will tell you the point source lights are bad (for the most part... there are ALWAYS exceptions). The more concentrated the originating point of light the harder and harsher the shadows (sometimes photographers want hard harsh shadows). This is why professional flash photographers use umbrellas, soft boxes and other modifiers to simulate spreading the source of light over a much larger area which softens shadows.

I like LED lighting, it just needs to be designed for the use case it is implemented for. A frosted diffuser can go a very long was in making a hard point source LED light act like a larger (more surface area) light source... for like a penny's worth of plastic. Color balance is another area that can be done well or done poorly. It really comes down to having someone properly educated in the physics of light on the design team. I would bet that most cheap products are designed by product engineers that have little education on the physics of light.

My custom built aquarium lighting has 6 independent channels (6 different colors of LED's) that I can balance to my hearts content to produce different lighting effects to spur plant growth and change the perceived color of the plants, stock and hardscape. Cree and Luxeon are the LED manufactures that I prefer. You can count on the wavelength emitted by their LED's matching their published wavelength graphs.