jimk@fab4.UUCP (Jim Kendall) (10/13/90)
There was discussion sometime ago concerning a cheap blue LED. Could one of you kind souls please e-mail me as to who makes it? Tanx a milyin... -- Jim Kendall +------------------------------+ O-O - - o o The fab way: jimk@fab4 | This message was prerecorded |_ | ^ ' The gear way: fab4!jimk +------------------------------+ \__ ~
a143@mindlink.UUCP (Ed Meyer) (10/14/90)
> jimk@fab4.UUCP writes: > > There was discussion sometime ago concerning a cheap blue LED. > Could one of you kind souls please e-mail me as to who makes it? > > Tanx a milyin... > > -- > Jim Kendall +------------------------------+ O-O - - > [ ... signoff deleted ... ] Jim, here's the kind of info I posted way back when ... sorry I don't have the original posting. BLUE LED from Marktech, 5 Hemlock Street, Latham, NY (12110), Voice (518) 786-6591, Fax (518) 786-6599 Specs: MT1018D-BL (Diffused); MT1018-BL (Clear) Silicon Carbide Technology, 470 nm peak wavelength, If=60 mA max., Vr=5 V max.,Temp.Op.=-20 to 80 C (store -55 to 100C) Vf @ 50mA = 2.9 min, 3.2 typ, 4.0 max Iv @ 50mA = 10.0 mcd @ 470 nm with View_Angle= +/- 7 deg. (spectral half width = 70 nm) Hope this helps.
LANGFRD@osu-20.ircc.ohio-state.edu (david langford) (10/18/90)
Does anyone where Blue L.E.D.'s can be purchased for LESS than $10.
The only place I have seen them is Jameco and they were $9.95!!!!
This is a LITTLE too much for me...
Thanx..
David Langford
langfod@ohstmvsa.ircc.ohio-state.edu
or above addressee5391aa@hydra.unm.edu (Duke McMullan n5gax) (10/18/90)
In article <12630655371015@osu-20.ircc.ohio-state.edu> LANGFRD@osu-20.ircc.ohio-state.edu (david langford) writes: >Does anyone where Blue L.E.D.'s can be purchased for LESS than $10. >The only place I have seen them is Jameco and they were $9.95!!!! >This is a LITTLE too much for me... It's a little rich for my blood, too...but wait a while. I recall a few years back when wimpy red LEDs were selling for >$10. "...and this, too, shall pass away." They'll get cheaper fast, when production yields rise and demand increases. They remain a curiosity at this point...you'll see _very_ few specified as manufacturing components. Now. Who can tell me where to find a blue diode _laser_ for <$100? ;^) d -- "It's my _dessert_ that's gross! Look, a thermos full of phlegm!" -- Calvin Duke McMullan n5gax nss13429r phon505-255-4642 ee5391aa@hydra.unm.edu
henry@zoo.toronto.edu (Henry Spencer) (10/18/90)
In article <12630655371015@osu-20.ircc.ohio-state.edu> LANGFRD@osu-20.ircc.ohio-state.edu (david langford) writes: >Does anyone where Blue L.E.D.'s can be purchased for LESS than $10. >The only place I have seen them is Jameco and they were $9.95!!!! Don't get your hopes too high. These are high-tech, hard-to-make parts with a small market and little competition. -- "...the i860 is a wonderful source | Henry Spencer at U of Toronto Zoology of thesis topics." --Preston Briggs | henry@zoo.toronto.edu utzoo!henry
king@dciem.dciem.dnd.ca (Stephen King) (10/23/90)
In article <1990Oct18.035324.10362@ariel.unm.edu> ee5391aa@hydra.unm.edu (Duke McMullan n5gax) writes: >In article <12630655371015@osu-20.ircc.ohio-state.edu> LANGFRD@osu-20.ircc.ohio-state.edu (david langford) writes: >>Does anyone where Blue L.E.D.'s can be purchased for LESS than $10. >>The only place I have seen them is Jameco and they were $9.95!!!! >>This is a LITTLE too much for me... Be glad you don't live up here in Canada, where these little critters are costing me $32.46 EACH (Canadian dollars). >They'll get cheaper fast, when production yields rise and demand increases. >They remain a curiosity at this point...you'll see _very_ few specified as >manufacturing components. Not according to Siemens, the only manufacturer of blue LEDs that I know of. Apparently, it is not possible to manufacture large slabs of silicon carbide of the form necessary for making the LEDs. Unfortunately, I can't find my Siemens opto-electronic manual at the moment, so I can't quote from it. If anyone is interested, I'll dig it up and post the article. -- Se non e` vero, e` ben trovato ...{utzoo|mnetor}!dciem!dretor!king king@dretor.dciem.dnd.ca
jgk@demo.COM (Joe Keane) (10/24/90)
In article <1990Oct18.153309.10837@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: >Don't get your hopes too high. These are high-tech, hard-to-make parts >with a small market and little competition. LEDs a small market? Do you know something we don't? From what i can see, the prices should come down and there'll be a big demand.
pgc@csadfa.cs.adfa.oz.au (Phil Clark) (10/25/90)
In article <3681@dciem.dciem.dnd.ca>, king@dciem.dciem.dnd.ca (Stephen King) writes: > In article <1990Oct18.035324.10362@ariel.unm.edu> ee5391aa@hydra.unm.edu (Duke McMullan n5gax) writes: (Stuff deleted) - Be glad you don't live up here in Canada, where these little critters are - costing me $32.46 EACH (Canadian dollars). - >They'll get cheaper fast, when production yields rise and demand increases. - >They remain a curiosity at this point...you'll see _very_ few specified as - >manufacturing components. - Not according to Siemens, the only manufacturer of blue LEDs that I know - of. Apparently, it is not possible to manufacture large slabs of silicon - carbide of the form necessary for making the LEDs. Unfortunately, I can't - find my Siemens opto-electronic manual at the moment, so I can't quote from - it. I saw somewhere recently that someone (I think it was IBM) had developed a Blue solid state laser diode. This was apparently done using frequency doubling techniques and they claimed efficiency of something like 10%. Has anyone seen anything about this and any idea of the cost yet? Phil Clark Department of Computer Science, Phone: (VK1PC) Australian Defence Force Academy, +61 6 268 8157 Email: Northcott Drive, Campbell, Fax: pgc@csadfa.cs.adfa.oz.au Canberra, Australia, 2600. +61 6 268 8581
onymouse@netcom.UUCP (John Debert) (10/28/90)
From article <3931@demo.COM>, by jgk@demo.COM (Joe Keane): > In article <1990Oct18.153309.10837@zoo.toronto.edu> henry@zoo.toronto.edu > (Henry Spencer) writes: >>Don't get your hopes too high. These are high-tech, hard-to-make parts >>with a small market and little competition. > > LEDs a small market? Do you know something we don't? From what i can see, > the prices should come down and there'll be a big demand. Several companies are in fact already starting work on developing LED video displays, including a HDTV display, in several sizes including a large, wall- hung display. There is also a plan to build a small hi-res 1 inch display for tiny TV's, etc.
tom@syssoft.com (Rodentia) (11/03/90)
In article <15692@netcom.UUCP> onymouse@netcom.UUCP (John Debert) writes: [previous discussion deleted] >Several companies are in fact already starting work on developing LED video >displays, including a HDTV display, in several sizes including a large, wall- >hung display. There is also a plan to build a small hi-res 1 inch display for >tiny TV's, etc. Anyone making a tricolor LED yet? It seems that you could use pulse width modulation to get a pixel of any color at relatively low power. Theoretically, how would power consumpion compare to LCD shutter solutions? -- Thomas Roden tom@syssoft.com Systems and Software, Inc. Voice: (714) 833-1700 FAX: (714) 833-1900
fng@questor.wimsey.bc.ca (Felix Ng) (11/04/90)
tom@syssoft.com (Rodentia) writes: > > Anyone making a tricolor LED yet? It seems that you could use > pulse width modulation to get a pixel of any color at relatively > low power. > > Theoretically, how would power consumpion compare to LCD shutter > solutions? > I think Radio Shack sells one. Red and green with DC and yellow with AC. Felix Ng Vancouver, B.C. fng@questor.wimsey.bc.ca
roy@phri.nyu.edu (Roy Smith) (11/06/90)
tom@syssoft.com (Rodentia) writes: > Anyone making a tricolor LED yet? fng@questor.wimsey.bc.ca (Felix Ng) replies: > I think Radio Shack sells one. Red and green with DC and yellow with AC. I think Rodentia (presumably not tom@syssoft.com's real name) meant an LED with all three primaries, i.e. red, blue, and green that you could mix anyway that you like. The red/green/yellow LEDs are just a red and a green LED back-to-back. One polarity lights one, the other polarity lights the other, and AC lights them both, a half-cycle each. I could see packaging all three in one plastic case, but I don't see how you make it work with only 2 pins. The minimum pin count I could see is 3, with the 3 LEDs delta connected, allowing you to light any one or two at a time. If you wanted to light all three at once, you would need 4 pins; an anode for each and common cathodes (or the other way around, if you prefer). It would certainly be a heck of a lot simplier that getting the odd bipolar voltages you'd need in the delta connection. tom@syssoft.com (Rodentia) again: > how would power consumpion compare to LCD shutter solutions? My latest Digi-Key catalog shows most of the LEDs drawing 70-90 mW. Even for a modest resolution 512 x 512 display at 70mW/pixel, you'd be drawing 18 kW! Hardly low power. -- Roy Smith, Public Health Research Institute 455 First Avenue, New York, NY 10016 roy@alanine.phri.nyu.edu -OR- {att,cmcl2,rutgers,hombre}!phri!roy "Arcane? Did you say arcane? It wouldn't be Unix if it wasn't arcane!"
ardai@teda.UUCP (Mike Ardai) (11/06/90)
In article <eeP4R1w163w@questor.wimsey.bc.ca> fng@questor.wimsey.bc.ca (Felix Ng) writes: -tom@syssoft.com (Rodentia) writes: - -> -> Anyone making a tricolor LED yet? It seems that you could use -> pulse width modulation to get a pixel of any color at relatively -> low power. -> -I think Radio Shack sells one. Red and green with DC and yellow with AC. :-) :-) Actually, Cree Research Inc. has advertised a 3-die LED (RGB). Their phone number is 1-800-LED-BLUE. I haven't seen a blue (or polychrome) LED yet, but it sure sounds like a fun thing to have... /mike -- \|/ Michael L. Ardai Teradyne EDA East --- ------------------------------------------------------------------------- /|\ ...!sun!teda!ardai (preferred) or ardai@bu-pub.bu.edu
cook@stout.atd.ucar.edu (Forrest Cook) (11/06/90)
In article <1990Nov2.171429.28170@syssoft.com> tom@ssi.UUCP (Rodentia) writes: >Anyone making a tricolor LED yet? It seems that you could use >pulse width modulation to get a pixel of any color at relatively >low power. Funny you should mention this, I have been looking for such a beastie. I programmed an antique MC68705P3L micro to step through R G and B PWM duty cycles cyclically and Voila- a color pixel that changes through 4096 colors. It doesn't really look like 4096 colors, but that is the resolution. The biggest problem with this gadget is that the three colors of LEDs are in separate packages and don't diffuse together very nicely. The best mixing I managed to get was by viewing the three LEDs from about 4 feet away using a projector lens a few inches from my eyes. The second method that I have settled on is to put the 3 LEDs into a flashlight reflector and replace the clear glass with some diffuse smoked glass. There are still primary color fringes on the edges. A nice 3 color diffused LED in one package would make for a much better pixel. Why did I go to all of this trouble, you ask? Mainly to satisfy my curiosity. Could the world use an RS-232 controlled color pixel? >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. -- ^ ^ Forrest Cook - <<< We all P for IP, We all BM for IBM >>> /|\ /|\ cook@stout.atd.ucar.edu WB0RIO (This posting is my OPINION) /|\ /|\ {husc6|rutgers|ames|gatech}!ncar!stout!cook
koch@motcid.UUCP (Clifton Koch) (11/06/90)
From article <9096@ncar.ucar.edu>, by cook@stout.atd.ucar.edu (Forrest Cook): -> 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. -> Anyone who would run all the LEDs at once must own a power station :-> In real life LED applications, they're always multiplexed, even in el cheapo digital clocks. For a NTSC TV, the resolution would only have to be about 480 x 330. Only 1 horizontal scan line would likely be on at any given time, so the power drops to 330 x .02 x 3, or just under 20 watts. A wee bit more reasonable.
koch@motcid.UUCP (Clifton Koch) (11/06/90)
> be about 480 x 330. Only 1 horizontal scan line would likely be on at any > given time, so the power drops to 330 x .02 x 3, or just under 20 watts. A Oops, forgot to stick in the voltage. Make that 330 x .02 x 3 x 2, or just under 40 watts.
umapu02@cc.ic.ac.uk (D.A.G. Gillies Supvsr Dr K.J. Bignell) (11/07/90)
In article <1990Nov5.172318.1487@phri.nyu.edu> roy@phri.nyu.edu (Roy Smith) writes: >tom@syssoft.com (Rodentia) writes: >> Anyone making a tricolor LED yet? > >fng@questor.wimsey.bc.ca (Felix Ng) replies: >> I think Radio Shack sells one. Red and green with DC and yellow with AC. > > I think Rodentia (presumably not tom@syssoft.com's real name) meant >an LED with all three primaries, i.e. red, blue, and green that you could >mix anyway that you like. The red/green/yellow LEDs are just a red and a >green LED back-to-back. One polarity lights one, the other polarity lights >the other, and AC lights them both, a half-cycle each. > > I could see packaging all three in one plastic case, but I don't >see how you make it work with only 2 pins. The minimum pin count I could >see is 3, with the 3 LEDs delta connected, allowing you to light any one or >two at a time. If you wanted to light all three at once, you would need 4 >pins; an anode for each and common cathodes (or the other way around, if >you prefer). It would certainly be a heck of a lot simplier that getting >the odd bipolar voltages you'd need in the delta connection. > >tom@syssoft.com (Rodentia) again: >> how would power consumpion compare to LCD shutter solutions? > > My latest Digi-Key catalog shows most of the LEDs drawing 70-90 mW. >Even for a modest resolution 512 x 512 display at 70mW/pixel, you'd be >drawing 18 kW! Hardly low power. 70-90mW is pretty high for an LED. Most of the ones I use draw about 20 mA with a forward voltage of about 2.2 V = ~45mW . But this is the instantaneous power consumption. The brightness of an LED is a fairly sharp exponential of the input current. So driving it with 5 times rated current and a 10% duty cycle (should be rugged enough to stand this) will give the same subjective brightness, but halve the power. Besides,the LEDS's in catalogues are discrete, butch devices for indicators. If they were to be used in a matrix display they would be individually very small, with concomitant reduction in power needs. And as for tri-colour LED's, give 'em a chance - the blue LED has only been available for about 4 months now. It was always the holy grail of LED people, for precisely the reason that a tri-colour LED is potentially a very useful device... -- ___________________________________________________________________________ ----Saddam Hussein - nuke him 'till he glows, then shoot him in the dark--- ---(c) The Amazing Underwater Chocolate Christmas Cracker Motto Factory---- ---------------------------------------------------------------------------
cmpeters@eos.ncsu.edu (C MAVERICK PETERSEN) (11/07/90)
In article <16361@teda.UUCP>, ardai@teda.UUCP (Mike Ardai) writes: > In article <eeP4R1w163w@questor.wimsey.bc.ca> fng@questor.wimsey.bc.ca (Felix Ng) writes: > -tom@syssoft.com (Rodentia) writes: > - > -> > -> Anyone making a tricolor LED yet? It seems that you could use > -> pulse width modulation to get a pixel of any color at relatively > -> low power. > -> > -I think Radio Shack sells one. Red and green with DC and yellow with AC. > :-) :-) > > Actually, Cree Research Inc. has advertised a 3-die LED (RGB). Their > phone number is 1-800-LED-BLUE. I haven't seen a blue (or polychrome) > LED yet, but it sure sounds like a fun thing to have... Yes, 'tis true that CREE Research Inc. (Research Triangle Park, NC) has _advertised_ a 3-die (RGB) LED. Let's emphasize that word _advertise_ though. When requesting a sample of their RGB, one of their service reps said, "Oh, we are 'still working' on that..." But they did send me a sample of one of their blue LEDs. Chris Petersen mav@eceugs.ncsu.edu cmpeters@eos.ncsu.edu