A filter device has a filter housing receiving a filter element defining a longitudinal axis and being in the form of a filter cartridge. After an electrode layer, composed of a layer of film, is formed on the support body, etching is performed and stripe electrodes are formed. The first optical path includes means for introducing a collimated incident beam of radiation into the eye and for directing a wavefront exiting from the eye to the sensor as retinal wavefront data. Suspension arm movement induces expansion and contraction of tension springs coupled to the rocker arms to augments shape changes at the track contact surface to optimize traction and steering control. This makes it possible to achieve a TFT array substrate on which a gate drive circuit and its wires have been monolithically formed, wherein the width of a frame part in which the a gate drive circuit and its wires are formed can be reduced. If desired, elliptical shapes or other suitable shapes providing a nonlinear path of ion travel may be employed.