Sensor module for measuring surfaces

Sensor module for measuring structures in a surface (1), especially on the surface of a moving finger on the sensor module, comprising a number of sensor elements (5) and an outer electrode (7) located adjacent to the detector elements ; wherein the sensor elements constitute an essentially linear array; the detector elements are coupled to electronic circuitry (4) positioned on a substrate (2), said wiring substrate conductor (15) coupling the sensor elements to the electronic circuitry comprising, and said electronic circuitry is adapted to measure the magnitude of the capacitance or AC impedance between the each of said number of sensor elements and the outer electrode; said array of detector elements is adapted to measure movement between the detector and the surface, the electronic circuitry being adapted to measure the capacitance or impedance between each sensor element and the outer electrode at chosen time points and to combine the measured values ​​to generate a representation of the model surface, the sensor elements are also coupled to at least one circuit (11) provides a current or variable voltage, thus coupling a signal through the sensor elements to the outer electrode, said outer electrode being provided with a chosen voltage, so that said electronic circuitry measures the magnitude of the capacitance or AC impedance between each of said number of detector elements which are provided with said signal and said outer electrode being provided with said chosen voltage; the characterized detector module being that said electronic circuitry comprises input means including at least two amplifier circuits, each amplifier circuit being coupled to a group of detector elements including at least two detector elements (5a, 5b, 5c, 5d) for amplifying the señalesdel same and for transmitting said signals to said electronic circuitry, each sensor element in each group to a different unit of excitation (11a, 11b, 11c, 11d) being coupled to energize each detector element in a predetermined sequence, thereby receiving circuit a signal amplifier single detector element of the group each time.