What is the Vcom adjustment?
A. For displays with a low level interface where the customer must supply many of the interface components, there is an adjustment called Vcom. This adjusts for small differences in the electrical characteristics of the glass. The drive circuitry must be tuned to match these characteristics for each individual display. The customer design must allow for this manual adjustment which is done by observing the display and minimizing optical patterns or distortions. For Sharp displays with a higher level interface built-in, the Vcom adjustment is made at the factory and rarely requires any field adjustment.
