A compact optical vibration transducer with photo IC

A compact optical vibration transducer which is based on compact disk (CD) optical pickup head with certain modifications is presented. High signal to noise (S/N) ratio measuring signal is achieved because a signal process integrated circuit (IC) has been integrated into a single chip with the photo detector in the transducer. Some design considerations about the selection of the models, focus servo and error analysis have been addressed in this paper. The experimental results show that the transducer can measure the signal with vibration frequency up to 5 kHz, amplitude about a few micrometer. The resolution of the transducer is 10 nm. When vibration signal is at frequency below 1 kHz, with the closed-loop operation, the maximum measurable amplitude of vibration can be extended to ±0.7 mm