> When DC component is such a problem, why not stick C's in series?

The C leakage will likely be higher than the LCD's plus if it rectifies
even a tiny little bit you are worse off than without. And all inexpensive
ceramic caps rectify more then a little bit.

The DC component must be very low for most high contrast low voltage LCDs,
as used in watches, surplus DVMs etc. As in <10mV or better. At 5V this
requires <0.2% deviation from 50% duty cycle. These numbers are for a
display that I have used. With DC component the life is measured in weeks
or months, without, years or tens of years.

Peter

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