ELECTROWETTING CELL AND METHOD FOR DRIVING IT

摘要

The electrowetting cel (15) that is primarily to be used as a variable focus lens, comprises a liquid chamber (50) containing a first and a second immiscible fluid (51, 52), which are in contact across a meniscus (14) and of which the first fluid (51) is a polar and the second (52) is electrically conductive. The liquid chamber (50) is provided with an inner face (18), at which a fluid contact layer (10) is present, which has an inherent attraction to the first liquid. An electrode is separated from the liquid chamber (50) through this fluid contact layer (10). The fluid chamber (50) is constructed such that it has a small diameter at an operating point (101) at the inner face (18) than at a point of tangency (102), while a tangent (R1) to the operating point (101) encloses a smaller angle with the optical axis (OA) of the cell (15) than a tangent (R2) to the second point (102). This results in the fact that the meniscus (14) that touches the inner wall (18) at the second point (102) is oriented towards the optical axis and that the cell (15) can have a low construction height.