kayrock66 wrote:In general you pay more for efficiency in LEDS. Efficiency being defined as light output divided by power input. When they manufacture a batch of LEDs they get good ones and no so good ones. They sort them by brightness and sell them off asking more for the brightest and less for the weaker ones.
I don't think reliability figures in much since these are solid state devices.
The examples you provided in your post aren't apples to apples comparison, one is a diffused type and the other is a clear wide angle type. The intensity is indicated by the mcd number. In general diffused LEDs aren't as bright as the water clear type.
The thing I'm learning about LEDs in this application is that you aren't so much interested in the intensity but the total luminus flux. The typical high brightness 5mm LED has a very narrow angle (20 degrees). The lens gathers most of the light coming out of the LED chip and concentrates in into a narrow beam, like a flashlight. But from my own Spoke POV and looking at pictures of others I realize that a wide viewing angle is probably more valuable than narrow one, even at the expense of intensity. I want people to be able to see the display over a wide angle, not just straight on. So its a balance between intensity and viewing angle. I saw some jumbo 10m LEDs with extremely high intensities but realized that this must be at the expense of viewing angle. Specific questions to 2 HK manufactures asking about the apparent paradox of these devices claiming to be just as wide, by several times brighter than the 5mm devices went unanswered.
So I'm going to try a stick with LEDs such as:
http://cgi.ebay.com/30x-Red-5mm-Wide-an ... dZViewItem
And see if I can get a better viewing angle One anticipated side benefit of the wide angle devices is that they produce a display with less striation. This is the effect were you can see brighter and darker circles making up the POV display due to the different angles of the individual LEDs in the array. When the LED viewing angle is narrow, small differences in LED mounting make big differences in perceived intensity and thus smoothness of the composit POV display.
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