Thanks for the comments, folks!
Ken Ramos wrote:Fust time I ever seen one'a dee'se close-up? I am familiar with diodes but not light emitting ones...so, where does the light come from? Evidently they don't get hot and all that or do they?
Ken, it's not nearly such a close view, but go take a look at this
"Christmas LED" post over in the old forums. The light comes from a thin layer just below where the contact wire connects.
The light from an LED is produced directly from electricity at low temperature. You could embed the raw chip in ice instead of plastic, and still get light. However, the conversion from electricity to light is not very efficient, typically only about as good as an ordinary incandescent bulb. The wasted electricity does get turned into heat, and you have to draw that heat off as fast as it is produced or the LED rapidly overheats and fails. The big difference from an incandescent bulb is that with the LED, high temperature is an unnecessary and undesirable side effect, rather than a required part of how it works.
Joan, I like to play with a lot of different kinds of subjects. Poke through my old postings, and you'll find a broad mix: insects, flowers, seeds, lichen, spiders, rocks, concrete, protozoa, polished wood, leaf veins, a badly machined setscrew, some waterlice, frost spikes, and a bunch of equipment shots. I got interested in closeup/macro photography to do insects, but now pretty much anything is fair game.
Doug, I thought the two photos made a nice pair. I did just the LED first, then realized that even with the scale bar, there was no good sense of just how small that thing is! Showing the whole board helps, but in retrospect I ought to have thrown in a third one to really put the size in context. Oh, what the heck -- let's do it now!
jmlphoto wrote:looks like a pile of silver is sweeping another pile off the edge.
It does, doesn't it? I presume that silver stuff is some kind of solder. But I'm surprised at how crystalline it looks. You can see on the side of the black slab and on the end of the gold wire, there are even some tiny isolated spots of silver, as if the stuff were sprayed on and a few drops scattered off to the side. Direct view through the microscope gives the same impression, maybe even stronger. I have no idea how these things are actually manufactured.
MacroLuv wrote:DaveW wrote:... He asked a friend who was up on modern electronics how you traced the circuit path through these? His friends reply was "only the chip designer knows that, you only have to know what tag to connect to these days!".
And you would hardly get an answer from designer. The designer is not a single person I bet.
In a high density chip, it may be that no human knows exactly what goes where on the physical chip. Final routing and layout is usually done by software. Sometimes whole blocks are constructed by software based on functional specifications. If a human really wants to know, she looks it up on a map produced by the software!
--Rik
I remember going down to the local drug store as a kid with a tube my father wanted me to check to get the TV up and running again. 
