EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: XOIIO on June 20, 2018, 02:28:01 am
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Hello all, so I need to find some very small smd LED's in an ice blue sort of color, I was thinking cyan but that's a little too green from the look of it.
The first ones appear to be 0402, though my calipers measure them at 1mm x .8mm or so.
The next ones will likely be trickier however, they are side emitting ones, measuring 1.65mm x 1.3mm counting the lens, or 1.65mm x .93 not counting the lens.
The last ones are 1.6mm x 1.9mm with four legs, though are single color, I can't find anything like them in lists/examples of smd LED's however, so I'm hoping one of you may be able to tell me what the package type is.
https://imgur.com/a/sxlrtEE
All in all I'm not feeling great at my chances of finding such small led's in cyan as it seems to be quite rare, maybe due to just how small they can make that type of LED? (though blue seems more readily available).
I've checked digikey, mouser and ebay, but so far not much luck.
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Cyan LED's are rare, keywords 495nm, 500nm, 505nm. They seem to be rejects of pure green//emerald green LED's 520-525nm.
I got some through-hole cyan LED's from eBay but no SMT anywhere.
I've only found blue-green phosphor-type SMT LED's, like VFD colour: https://www.eevblog.com/forum/projects/led-color-temperature-(smd-1206-0805)/msg1576420/#msg1576420 (https://www.eevblog.com/forum/projects/led-color-temperature-(smd-1206-0805)/msg1576420/#msg1576420)
The 4-pin LED's are a bi-colour package, but you only have one die in there.
I can find "0606" 4-pin SMD 1.6x1.6mm nothing at 2mm. Unless a 4-pin 0805.
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Cyan LED's are rare, keywords 495nm, 500nm, 505nm. They seem to be rejects of pure green//emerald green LED's 520-525nm.
I got some through-hole cyan LED's from eBay but no SMT anywhere.
I've only found blue-green phosphor-type SMT LED's, like VFD colour: https://www.eevblog.com/forum/projects/led-color-temperature-(smd-1206-0805)/msg1576420/#msg1576420 (https://www.eevblog.com/forum/projects/led-color-temperature-(smd-1206-0805)/msg1576420/#msg1576420)
The 4-pin LED's are a bi-colour package, but you only have one die in there.
I can find "0606" 4-pin SMD 1.6x1.6mm nothing at 2mm. Unless a 4-pin 0805.
Could be a 4 pin 0805, or that may at least fit, but yeah, I have gotten cyan colored LED's before by overdriving standard blue ones but that's tricky to do right and probably shortens the life considerably.
I realized I'm probably looking for more of an "ice blue" or 480nm ish led, though I've seen stuff advertised as cyan that looks close, I think that I have in mind is more in the blue range than that, but the ones in that post you linked look great too. I would probably have to get some of each and try them in person.
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Did some probing with a meter and looks like I'll need 2.8v led's, and those ones that might be dual color actually are, they are green which runs at .48v, and they also have red which just never gets used.
I may or may not change those, blue would be nice to match the theme but green for a battery indicator wouldn't be bad. I will need to use small ones though and not short out the other pin just to be safe in case they mapped it to a pin still for some reason.
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I ran into some "white" LEDs recently that I would certainly say could be called "ice blue". I think they were the Inolux HT-191TW. I threw them away when I saw how terrible they were as white, but they might work for your purposes. I tried to take a picture but can't really capture the color accurately.
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I've been using Kingbright domed 0603s (APTD1608), and apart from being crazy bright (~100µA is enough to light them up for indicator purposes) also have good color. The blues are pretty dang blue. The specs indicate a 30-60% view angle (40% for the blues), but it's more than that; you really need to tilt the board sideways before they visually start to fade. The domes mate nicely to light guides.
My brightness matched measurements, for "reasonably bright indicator use" (that's a technical term :)), 3.3V supply:
Color Vf R If
Red 1.8V 15k 100µA
Grn 2.5V 15k 53µA
Blue 2.5V 6k 133µA
I like using green for general purpose indicators on boards, a handful (a technical unit of measurement :)) of them won't add up to even 1mA.
http://www.kingbrightusa.com/product.asp?catalog_name=LED&product_id=APTD1608LQBC/D (http://www.kingbrightusa.com/product.asp?catalog_name=LED&product_id=APTD1608LQBC/D)
http://www.kingbrightusa.com/kcpartno.asp?sltSearch=PN&txtPartNo=APTD1608 (http://www.kingbrightusa.com/kcpartno.asp?sltSearch=PN&txtPartNo=APTD1608)
Sold by Mouser, Digikey, etc.
And, yeah, the blues are 480nm which is only ever so slightly green.
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Those links look useful for sure, the big challenge would be getting those to fit where the 0402 ones go, I also posted this on reddit and someone said what I'm looking for is probably at the 505nm mark, but then again I'll probably have to order multiple ones and compare the color in person, kingbright does have 470 which may be promising though.
I also came across these in my search from kingbright as well https://www.digikey.ca/product-detail/en/APT1608VRCXF%2fA-5MAV/754-2180-1-ND/7776822 (https://www.digikey.ca/product-detail/en/APT1608VRCXF%2fA-5MAV/754-2180-1-ND/7776822)
And these may work well for the side emitting ones if I could solder then basically sideways. https://www.digikey.ca/product-detail/en/SM1204PGC/492-1232-1-ND/2404415 (https://www.digikey.ca/product-detail/en/SM1204PGC/492-1232-1-ND/2404415)
So far my digi-key part has 10 of each, I just really want to find some 0402 ones since I'm already gonna be spending over 25 bucks on these darn things lol, hopefully I could get all the shipping cost in one go, but maybe there just aren't really any blue ones that small.
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Würth has 470nm LEDs.
https://katalog.we-online.com/en/led/WL-SMCW?sid=60e1c6ee22
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Well, think this is all digikey could offer, I added in some straight blue 0402 ones, hopefully I can do this project with what I've been able to find. I just have a bad feeling about having to mix and match colors if some are off, couldn't figure out what that side emitting package was either :/
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Just found ice blue 0402 and 1206 side emitting led's on aliexpress, another 20 bucks and waiting time but I should definitely be able to do this now.
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Hey all -
A few months back I manufactured a lot of 500nm cyan LEDs in an 0402 package. These are really high luminous intensity which makes them perfect for traffic lights and things of that nature. I can imagine that these would be useful for things like model railroads and things of that nature. If anyone needs some of these, then please let me know.
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