Design of an Ultrasonic Micro-Array for Near Field Sensing during Retinal Microsurgery

A method for obtaining the optimal and specific sensor parameters for a tool-tip mountable ultrasonic transducer micro-array is presented. The ultrasonic transducer array sensor parameters, such as frequency of operation, element size, inter-element spacing, number of elements and transducer geometry are obtained using a quadratic programming method to obtain a maximum directivity while being constrained to a total array size of 4 mm² and the required resolution for retinal imaging. The technique is used to design a uniformly spaced NtimesN transducer array that is capable of resolving structures in the retina that are as small as 2 mum from a distance of 100 mum. The resultant 37times37 array of 16 mum transducers with 26 mum spacing will be realized as a capacitive micromachined ultrasonic transducer (CMUT) array and used for imaging and robotic guidance during retinal microsurgery