GHOST IMAGE ELIMINATION IN AN IMAGE SENSOR EMPLOYING A VARIABLE FOCUS LENS

摘要

In an image sensor incorporating a variable focus lens of the electrowetting type, means are provided for reducing or substantially eliminating the occurrence of ghost images. A variable focus lens of the above-mentioned type comprises a housing (5) provided with a first fluid (A) and an axially displaced second fluid (B), the two fluids being non-miscible, in contact over a meniscus (14) and having different indices of refraction. First and second electrodes (2, 12) are provided and the shape of the to meniscus (14) is controllable in dependence on the application of a voltage between the first and second electrodes (2, 12). Various methods of reducing or substantially eliminating the occurrence of ghost images are prepared, including the alteration of the optical properties of an inner and/or outer wall of the housing (5), to reduce the reflectivity thereof, provision of means in the image sensor to intercept ghosting and appropriate selection of the material or combination of materials of which the housing (5) is formed.