Printed LED tape - Page 1
Forum section: electronics / general

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 15, 2015, 06:56:13 pm
content: Interesting new LED tape - LED wafers ground up and turned into ink for use in cheap printing processwww.ndeg.comManufacturer says single rolls will be available from Mouser at some point.

author: firewalker
author_rank: Super Contributor
timestamp: December 16, 2015, 08:12:37 am
content: If you power it with AC will it be more uniform?Alexander.

author: coppice
author_rank: Super Contributor
timestamp: December 16, 2015, 08:23:03 am
content: They have been doing this for a while.http://www.technologyreview.com/news/425955/lighting-sheets-made-of-tiny-leds/is a 4 year old report about their products. I guess there must be a good reason why they are not more widely known.

author: SeanB
author_rank: Super Contributor
timestamp: December 16, 2015, 09:18:56 am
content: Probably price and the initial low yield of the tape.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 16, 2015, 10:09:26 am
content: Takes time to develop and test processes. May also have been waiting for blue LED dice to get cheaper, maybe using GaN on silicon.

author: coppice
author_rank: Super Contributor
timestamp: December 16, 2015, 10:23:25 am
content: Quote from: mikeselectricstuff on December 16, 2015, 10:09:26 amI doubt they care much about cost right now. At this point they still seem to be targeting the kinds of application (e.g. fashion) where cost is almost irrelevant if there is fun new functionality available.

author: krivx
author_rank: Frequent Contributor
timestamp: December 16, 2015, 10:26:11 am
content: If there are "targeting" (waheeey) gun enthusiasts I expect they will need to design for cost, especially as a consumable item.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 16, 2015, 10:39:56 am
content: I doubt there's enough market for a product like unless it's significantly cheaper than the alternatives. Fashion is nowhere, gun targets are consumable.I'm surprised they don't list advertising (posters etc.) as a potential application as this is an area where cost is less of an issue if a product can offer something new.

author: tszaboo
author_rank: Super Contributor
timestamp: December 16, 2015, 11:17:57 am
content: So half the LEDs will be facing down, half of them will be inverse parrllel and half of them will be completely shorted with the expensive silver. The close up you showed also had uniformity issues. On the other hand it could be a good application for road signs or creative way to use illumination as part of a buildings appeal. Maybe if they would find a way to make it more organized. Like printing it on a ferromagnetic material, and then using magnets during the printing to make higher percentage of the LEDs useful.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 16, 2015, 12:03:58 pm
content: I'm not sure how they address the shorting issue, could just be by particle size of the non-LED constituent of the ink acting as a spacer.Seems like the LEDs end up flat, facing up or down. LED wastage probably isn't an issue other than maybe a slight cost - The only benefit from running on AC is more uniformity/density - I suspect you'd have thermal issues if you drove all LEDs at the same avarage power as the nominal rating for DC, but might be useful for non-continuous applications, e.g. flashing warning tape for safety applications

author: tszaboo
author_rank: Super Contributor
timestamp: December 16, 2015, 01:24:22 pm
content: Not just that. I mean, if you have randomly placed LEDs, how is the arrangement made? Say, you have one LED shorted with 2 in series, how will the currents go? Logic tells me that there will be quite significant difference and then maybe the single one dies during a burn-in, or the other two never lits up?On the other hand I'm sure there are endless possibilities for this.Maybe they should just invent a pick and place, which works on the microscopic level?

author: krivx
author_rank: Frequent Contributor
timestamp: December 16, 2015, 02:03:06 pm
content: Quote from: NANDBlog on December 16, 2015, 01:24:22 pmI would guess that they drop the LEDs onto the adhesive and then vibrate to shake off anything not attached, leaving a single layer.Alternatively they could attach the adhesive tape to a complete wager or wafer segment after it is cut up but before it is separated.

author: nova1200
author_rank: Contributor
timestamp: December 17, 2015, 01:16:42 am
content: Lots of info inhttp://semiconwest.org/sites/semiconwest.org/files/6_William%20Ray_Nth%20Degree.pdf

author: coppice
author_rank: Super Contributor
timestamp: December 17, 2015, 03:52:51 am
content: Quote from: nova1200 on December 17, 2015, 01:16:42 amSeveral interesting missing pieces seem to be filled in my those slides. They say the shape of the LEDs means that can only end up the right way or upside down, and >90% will be the right way up.