I have a simple circuit I built using a 7-segment LCD glass display and an ATTiny (just a simple timer for now). I was hoping to use the setup in a low power, single coin cell device (3.3V - 2.7V), but then I noticed that the recommended voltage on the LCD is 5V. I looked for lower voltage LCD panels (they use them in the little freebie calculators that give away, and those have little coin cells) but either I'm looking in the wrong place or they don't exist.
Never mind, I just tried using lower voltages, and I can almost get it usable at around 3V by putting a large (\$>10M\$) resistor from the signal pins to GND (somewhat legible at 2.9V and 50Hz PWM at 50% duty). I thought this might work because I think the segments are capacitive so the resistor increases RC and causes the segment to stay lit longer.
So my question is, does anyone know if there is a secret to getting these LCD panels to work at lower voltages? Ideally I'd like to get down around 2.5V and still somewhat readable, and I imagine it's possible since I've seen simliar devices that must be working from small 3V batteries. Or am I barking up the wrong tree and there exist LCDs somewhere that already use a lower voltage?
And before I get "there are 3V panels listed on Mouser, Digikey, etc.", I see that some of them come up as such in the product databases, but they are not <3 digits (I only need 2 digits) and the datasheets/technical drawings/whatever all still list 5V anyway, so I'm guessing they are all the same.