Operation of an ultrasonic sensor

An ultrasonic sensor comprising:

• a transmit signal generator for generating a plurality of ultrasonic signals, wherein each ultrasonic signal of the plurality of ultrasonic signals has a different phase delay relative to other ultrasonic signals of the plurality of ultrasonic signals;
• a plurality of signal lines, wherein a signal line of the plurality of signal lines is configured to transmit one ultrasonic signal of the plurality of ultrasonic signals;
• a two-dimensional array of ultrasonic transducers, wherein each ultrasonic transducer of the two-dimensional array of ultrasonic transducers is independently and selectively coupled to the plurality of signal lines;
• a first plurality of shift registers for storing control bits for applying a beamforming pattern of a beamforming space to the two-dimensional array of ultrasonic transducers, wherein the beamforming pattern identifies ultrasonic transducers of the two-dimensional array of ultrasonic transducers that are activated during a transmit operation for transmitting the plurality of ultrasonic signals by identifying a signal line of the plurality of signal lines to drive each ultrasonic transducer identified by the beamforming pattern, wherein the beamforming pattern focuses the plurality of ultrasonic signals to a location above the two-dimensional array of ultrasonic transducers, and wherein at least some ultrasonic transducers of the beamforming pattern are phase delayed with respect to other ultrasonic transducers of the beamforming pattern;
• a second plurality of shift registers for storing control bits for applying a receive pattern of the beamforming space to the two-dimensional array of ultrasonic transducers, wherein the receive pattern identifies at least one ultrasonic transducer of the two-dimensional array of ultrasonic transducers that is activated during a receive operation for receiving at least one reflected ultrasonic signal;
• and
• an array controller configured to control activation of ultrasonic transducers during the transmit operation according to the beamforming pattern and during the receive operation according to the receive pattern, the array controller configured to shift a position of the beamforming pattern within the first plurality of shift registers and to shift a position of the receive pattern within the second plurality of shift registers, such that the beamforming pattern and the receive pattern moves within and relative to the two-dimensional array of ultrasonic transducers, the array controller configured to repeat the transmit operation and the receive operation at a plurality of positions of the two-dimensional array of ultrasonic transducers.

A non-transitory computer-readable storage medium comprising instructions which when executed on one or more data processors, cause the one or more data processors to perform a method of using an ultrasonic sensor comprising a two-dimensional array of ultrasonic transducers, the method comprising:

• defining an activation sequence of a plurality of positions, wherein the activation sequence defines movement of the plurality of positions over the two-dimensional array of ultrasonic transducers for forming a focused ultrasonic beam at different locations over the two-dimensional array of ultrasonic transducers, the focused ultrasonic beam for capturing a pixel of an image;
• for each array position of the plurality of positions of the two-dimensional array of ultrasonic transducers:
• transmitting a plurality of ultrasonic signals according to a beamforming pattern over a plurality of signal lines, wherein each ultrasonic transducer of the two-dimensional array of ultrasonic transducers is independently and selectively coupled to the plurality of signal lines, wherein the beamforming pattern focuses the plurality of ultrasonic signals to a location above the two-dimensional array of ultrasonic transducers, wherein the beamforming pattern identifies a signal line of the plurality of signal lines to drive each ultrasonic transducer identified by the beamforming pattern, and wherein at least some ultrasonic transducers of the beamforming pattern are phase delayed with respect to other ultrasonic transducers of the beamforming pattern;
• and
• receiving at least one reflected ultrasonic signal according to a receive pattern at a receive input, wherein each ultrasonic transducer of the two-dimensional array of ultrasonic transducers is independently and selectively coupled to the receive input, wherein the receive pattern identifies at least one ultrasonic transducer of the two-dimensional array of ultrasonic transducers that is activated during the receiving;
• and
• repeating the transmitting and the receiving at the plurality of positions of the two-dimensional array of ultrasonic transducers, wherein the transmitting and the receiving for a subset of positions of the plurality of positions are performed simultaneously.