doug@key.COM (Douglas N. Good) (11/13/90)
cook@stout.atd.ucar.edu (Forrest Cook) writes: >>Theoretically, how would power consumpion compare to LCD shutter >>solutions? >Well, for a worst case scenario: how about a decent resolution LED >screen of 1024 X 1024 and 3 LEDs per pixel at 20ma per LED: >1024 X 1024 X .02 X 3 = 63000 AMPS! (approximately) >Multiply that by approximately 2 volts per LED and you get 126KW. >That's for an all white screen, of course. >Color balance would be a nightmare too. >Of course, someone could just have a row of 1024 LEDs and a spinning >mirror and cut that down to a reasonable 120 Watts, but I don't know how >easy the optics would be or how bright the display would be. Why not multiplex the thing?! Then you only have one 20mA LED running at any one time. Actually, you'll probably want to strobe several LEDs at one time to get the duty-cycle of individual pixels up. Otherwise you're going to have some pretty severe brightness problems. (My guess is that a duty cycle of 1/(1024*1024) would be way to low to be able to tell that the LED is on -- for that matter, the LED may never turn on!) I know that LED video can be done -- I've seen working LED TVs (using red and green). Granted, the resolution was low (probably 256 x 256), but I'm SURE that they're not pumping a city-block worth of power into the thing!!! You're biggest problem is going to be the 1024 * 1024 * 3 = ~3 _MILLION_ LEDs that you'll have to put into the thing (unless you want to use the spinning mirror ;-). We're not talking about a trivial manufacturing process here! --Doug -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Douglas Good Amdahl Corporation, Key Computer Laboratories doug@key.amdahl.com || ...!{pacbell,sgi,amdahl}!key!doug -- Douglas Good Amdahl Corporation, Key Computer Laboratories doug@key.amdahl.com || ...!{pacbell,sgi,amdahl}!key!doug
tom@syssoft.com (Rodentia) (11/16/90)
In article <2246@key.COM> doug@key.COM (Douglas N. Good) writes: >You're biggest problem is going to be the 1024 * 1024 * 3 = ~3 _MILLION_ >LEDs that you'll have to put into the thing (unless you want to use the >spinning mirror ;-). We're not talking about a trivial manufacturing >process here! Good point. What about LED arrays in the same fashion that LCD arrays are currently used to make screens? Anyone make these for red or green LED's yet? (I have seen segmented ones and the silent news display screens, but I meant to a finer pitch). Are dense LCD arrays easier to make? It seems someone could make a fine array with teeny-tiny LEDs to keep the power consumption lower as well as addressing circuitry to keep from needing a bazillion wires. -- Thomas Roden tom@syssoft.com Systems and Software, Inc. Voice: (714) 833-1700 FAX: (714) 833-1900