Three-dimensional space equivalent transform principle and tentative design of capacitive displacement transducer with 10nm resolution

摘要

From principle of capacitive displacement transducer of phase modulation main problems that may be appeared in the measurement system with 10nm resolution are analyzed. First one-one corresponding relation among pitch W of spatial field of scale electrodes, time period T and phase shift ω of the output signal is introduced. Thereby the theoretical foundation through reducing planar geometrical figure of the transducer to increase resolution is established. The three-dimensional equivalent transform principle and other methods are further put forward to scatter the dense figure and reduce machining difficulties. The principle also could be used for some other grating transducer. Then the scheme resolving lead wire problem is given. Present technology machining electrodes is explained. Better Micro Electro Mechanical System (MEMS) technology is indicated. But above method is insufficient to get 10nm resolution. So PLL is given, which could achieve higher subdivision number. The scheme with 10nm resolution will be more perfectly realized through above-mentioned three aspects. Finally it is introduced that the transducer technique is transplanted to grating. Higher resolution is expected by use of Micro Optical Electro Mechanical System (MOEMS) and grating to get smaller pitch to further resolve the design problems of the transducer with nm resolution.