Eink always could be driven quickly. The issue is that LCDs are more powerful efficient at high refresh rates
EInk needs a lot of power to move the heavier ink particles around. If you are doing that more and more rapidly, then even more power is drawn.
By 75Hz, I'm almost certain that LCD is far more power efficient. The LCD pixel (aka the liquid crystal) is a glorified capacitor, it takes some power to charge but it's exceptionally 'light' compared to eink.
That's why LCDs can go faster and faster. It's just physics. A capacitor / twisted crystal uses less power to turn on or off than EInk.
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EInks advantage is that if you turn off power, the ink stays put. So you spend a ton of power moving the ink around and then save lots and lots of power over the next seconds, minutes or more.
That's why EInk is ideal for once-a-day updates of prices (or other retailer tasks). The less you update, the less power used.
EInk needs a lot of power to move the heavier ink particles around. If you are doing that more and more rapidly, then even more power is drawn.
By 75Hz, I'm almost certain that LCD is far more power efficient. The LCD pixel (aka the liquid crystal) is a glorified capacitor, it takes some power to charge but it's exceptionally 'light' compared to eink.
That's why LCDs can go faster and faster. It's just physics. A capacitor / twisted crystal uses less power to turn on or off than EInk.
---------
EInks advantage is that if you turn off power, the ink stays put. So you spend a ton of power moving the ink around and then save lots and lots of power over the next seconds, minutes or more.
That's why EInk is ideal for once-a-day updates of prices (or other retailer tasks). The less you update, the less power used.