Layer switching for an ultrasound transducer array
A multi-layer transducer operates with only one system channel per element. Passive switching connects the layers differently for transmit than for receive operation, such as connecting two layers in parallel for transmit and in series for receive. Any passive switching may be used, such as current and voltage limiting circuits. Tuning may be passively switched. Different tuning circuits are passively switched as a function of voltage level between transmit and receive operations.
1. An ultrasound transducer element system, the system comprising:
at least one ultrasound transducer element comprising at least first and second layers of transducer material having a single center terminal between the first and second layers, each of the first and second layers of transducer material operable to convert between electrical and acoustic energies based on a transduction nature of the transducer material;
a transmit beamformer channel connected with the element such that both first and second layers are responsive to a same transmit waveform, the transmit waveform applied to the single center terminal between the first and second layers;
a receive beamformer channel connected with the element and configured such that signals generated by both the first and second layers, in response to acoustic echoes to acoustic energy transmitted by the transmit beamformer, are provided to the receive beamformer channel;
a passive switching circuit connected between and with the single center terminal and both of the transmit beamformer channel and the receive beamformer channel.
2. The system of claim 1 further comprising:
a single coaxial cable connecting both the first and second layers with the transmit and receive beamformer channels.
3. The system of claim 1 wherein the passive switching circuit is operable to switch between connecting the center terminal between the first and second layers with the transmit beamformer channel and connecting the receive beamformer channel across both the first and second layers.
4. The system of claim 3 wherein the first layer is poled in a substantially opposite direction as the second layer.
5. The system of claim 3 wherein the passive switching circuit comprises a current limiting passive switch and a first voltage limiting passive switch connected with an outer terminal of the first layer, the outer terminal on an opposite side of the first layer as the center terminal, and a second voltage limiting passive switch connected with the center terminal.
6. The system of claim 1 wherein the first layer is poled in a substantially same direction as the second layer.
7. The system of claim 1 further comprising:
a tuning circuit; and
wherein the passive switching circuit is connected with the tuning circuit, the passive switching circuit operable to connect the tuning circuit with the element for a first mode and disconnect the tuning circuit from the element for a second mode.