An optical encoder assembly and a method for measuring a rotation angle in which optical beams are spread over the circumference of a rotating optical disk by means of optical guides. The first and second sub-frames may have corresponding pluralities of image elements, with each image element of the second sub-frame spatially offset an offset distance from a corresponding image element of the first sub-frame. The loudspeaker is located some distance away from the sound-emitting opening and the connecting channel between the loudspeaker and the sound-emitting opening comprises the cavity in which the battery is accommodated. The glass powder mixed in the preparation of the photoelectrode can improve dispersion properties of light and can enhance use efficiency of light, thereby increasing the energy conversion efficiency of the dye-sensitized solar cell. Firstly the base element of the sensor element is mounted on the base element of the connector piece, a full-area connection being generated between the mounting surfaces of the two base elements.