[time-nuts] [OT] Ikea Lamp

[Dave Martindale]

If you care about accurate colour rendering, stick with incandescent, 
preferably halogen.  "White" LEDs are actually blue LEDs coated with a 
phosphor that absorbs some of the blue light and emits approximately 
yellow instead.  If you look at the spectrum, you'll see a broad yellow 
peak and a narrower blue peak.  Your eyes see it as approximately white, 
but it's deficient in red and green compared to a black body emitter 
like hot tungsten.  On the other hand, it's not as spiky as the output 
of fluorescents.

The particular IKEA units I have both look approximately "daylight" in 
colour temperature, and the colour is pretty uniform across the 
illuminated field (except for the very edge, which is yellow, but that's 
probably due to chromatic aberration in the lens, not the LED source).  
They work better than most of the LED flashlights I've seen, which tend 
to have large intensity and colour changes between the centre and the 
edge of the illuminated field.

     Dave

On 30/01/2010 07:49, paul swed wrote:
> IKEA and $39 per lamp. Sounds like some pretty good margin in the sale.
> I guess these LED things will be main stream and save the world when we see
> them at walmart for $6.
>
> On my bench I converted to 60 watt halogen lamps compared to the 100 watt
> lamp.
> Equivalent color spectrum to the traditional lamp also. For as many hours as
> that light is on. I suspect I am saving some money in the long run.
>
> Curious are these lights truly white or do they tend towards a traditional
> lamp spectrum.
> Regards
>
>