Arfa Daily wrote:

"John Doe" wrote in message
"Albert Manfredi" wrote:
wrote:

Issues with LEDs today:

Color rendering
Diffusion

Once those are solved effectively, they will be excellent
alternatives. My guess is 5 years to color rendering, and 5 more to
diffusion. Most LEDs today filter a single color to a specific
monochromatic output. Even the LED-type flashlights are very
heavily skewed to the blue end of the spectrum in order to get
sufficient brightness, and require multiple LEDs to get even a
minor beam with very poor diffusion.

But you can use a combination of red, green, and blue high intensity
LEDs, to create any variant of "white" that you prefer. From what
Ive read so far, the efficiency of the new high intensity LEDs is
almost identical now to that of CFLs, which means about the same
lumens for 1/4 or 1/5th the power of an equally bright incandescent
bulb.

Don't believe everything you read.

Experience is the best teacher.

In other words, LEDs suck for bright light sources.

However, the hype is good for selling them to fools over the
TV/Internet. Like that one guy selling LED light bulbs on TV (USA). He
doesn't explicitly say that they're bright as a lightbulb, but they
are in a lightbulb package and used in the commercial as if they were
a lightbulb. Some people probably fall for that.

The weird thing about LEDs is that they would last such a long time
that they wouldn't need replacement. In principle, you can build
them right into the lamp itself. Or in walls, or whatever.

Right, but pointless except for low light applications.


I have a friend who has LED downlighters as the only source of light in his
shop. They are perfectly bright and adequate for the job, if a little 'cold'
in colour temperature. Also, a local photography shop uses similar ones for
its window display, and again, the only comment you would make is that they
are a little cold. The specifications for up to date ones would certainly
suggest that they are on a par in terms of light output and beamwidth, with
comparable fitting halogens. With a bit of work, I'm sure that they will
also get to the point where they can replace a standard filament bulb, in
the same sized package, unlike a CFL which has to accommodate the ballast. I
think it might be a case of 'ya gets wot ya pay fer'

The brightest LEDs do unfortunately have that cool blue 7000K or so colour temp.
There's a significant trade off in efficiency for the 3000K ones.

Graham