Help to find a good transflective display - Page 1
Forum section: electronics / projects

author: ipscell
author_rank: Newbie
timestamp: November 20, 2019, 07:49:09 pm
content: So I want to make a low-power digital password/notes keeper. I'd like to use the enclosure from a bar phone with QWERTY keyboard like Nokia E72 or Blackberry 8700 but I can't find a transflective display of a suitable size. Since it will be battery-powered, I want a transflective display so if there's enough light, I can turn the backlight off completely, I really liked this in my Psion 5MX. So far the only more or less suitable display I was able to find is Sharp LS027B7DH01A - 400x240, 2.7" but it's too wide, most phones of this kind have displays 2.36~2.8", 320x240.Any suggestions regarding a low-power display that will fit inside the phone enclosure? I also don't like the idea of using e-ink displays because of their refresh rate but if I won't find anything better, I may consider them as well.

author: mark03
author_rank: Frequent Contributor
timestamp: November 20, 2019, 09:26:11 pm
content: Good luck!Despite some nice technologies having been out there for a decade or more, transflective screens have never really taken off in the market, except a few niche applications like some smartwatches (but not Apple) and bicycle computers. I remember when the OLPC (one laptop per child) came out with that display from a startup (forget the name) which was poised to make a killing in the laptop market. Never happened. I think it is "form over function:" marketing does not trust customers to value awesome battery life, or sunlight readability, over the general attractiveness of the screen, and because there are always compromises involved, they stick with the "safe" TFT.I think your best chance is to re-think your enclosure and design it around a transflective screen you can actually buyBesides the Sharp memory LCD line, Japan Display (JDI) has their own line of low-power, transflective displays. One buzzword to search for is "memory in pixel." Anyway, you can actually buy some of them now at Digikey, although they are fabulously expensive. The panel sizes are pretty much the same as Sharp, too, because it's the same niche markets that are driving both.I used to believe the free-market dogma that "once consumers demand X, companies will provide it" but now I have seen the light and I realize it is all down to what marketing departments decide to say that consumers want, not what they actually want...

author: oPossum
author_rank: Super Contributor
timestamp: November 20, 2019, 09:35:03 pm
content: The OLPC LCDs where from Pixel Qi. They went out of business when they could no longer get anyone to fab their designs.Several of the Nintendo Gameboy used transflective LCDs. No idea if they would be suitable for your application.

author: ipscell
author_rank: Newbie
timestamp: November 21, 2019, 03:29:54 pm
content: QuoteOddly enough, they have same size and resolution options as Sharp displays doQuoteSo trueQuoteThat's a shame, I really want to use that nice keyboard and optical trackpad from Nokia...QuoteSalvaging is not a bad idea by the way. I think I should look into old PDAs and whatnot, maybe I'll find a decent display to salvage. Gameboy display is not the best one to be honest but it fits into the phone enclosure and I haven't decided yet what am I willing to sacrifice more, a good display or a convenient enclosure.Thanks for the answers!

author: ebclr
author_rank: Super Contributor
timestamp: November 22, 2019, 12:21:26 am
content: It's not exactly what you are looking for, but "maybe" another wayhttps://pt.aliexpress.com/item/33035028483.html?spm=a2g0o.productlist.0.0.27492a2bz1RYbd&algo_pvid=a65f4f1a-c099-456e-8608-e1b41fc366c9&algo_expid=a65f4f1a-c099-456e-8608-e1b41fc366c9-43&btsid=197193af-f678-43ea-9a9d-8c1e70d46278&ws_ab_test=searchweb0_0,searchweb201602_9,searchweb201603_52

author: ipscell
author_rank: Newbie
timestamp: November 22, 2019, 05:52:39 pm
content: This device uses conventional transmissive LCD, isn't it? I want to keep power consumption below ~0.3W, so constantly backlit displays are not an option.