I just picked up some of the high efficiency Vishay 7-segment displays (red) after having used in the past much less efficient ones. I just got them in the mail today. Just trying one of the segments with 5V and a 15k/5% resistor gave me 220uA of current, suggesting a drop of
1.7V on the LED segment, itself. And the brightness was just fine for my needs. I pushed it a little harder with a 6.8k/5% and got about 480uA, suggesting a drop of 1.74V, and the brightness was more than I'd probably need. So with a 3X mux for 3 digits, even that much would only require driving them at about 1.5mA on a 1/3rd duty. Which is better than I'd hoped -- less than 2mA averaged current per segment in a multiplexed display of 3 digits.They are cheap and available in hobbyist qtys (50 cents each in 1's at Allied [TDSR1360].) What I'm curious about is if there are others I might also consider in this area of performance. Either cheaper and as good or just better. I'm not thinking exclusively about red - so I'm interested in particularly efficient 7-seg displays in other colors, as well. But red is good, too. I'm just not well-versed on the various manufacturers and who else might also be competing in this area.
Thanks, Jon