Ultrasound imaging with sparse array probes
Sparse arrays of transducer elements may be beneficial in providing ultrasound transducer probes with a wide total aperture while containing a manageable number of transducer elements. Sparse arrays made with bulk piezoelectric materials or with arrays of micro-elements can be effectively with ping-based multiple aperture ultrasound imaging techniques to perform real-time volumetric imaging.
1. A ping-based ultrasound transducer probe comprising:
an array of ultrasound transducing micro-elements, where each micro-element has a diameter less than 500 microns;
a first group of micro-elements electrically connected to a first signal conductor;
a second group of micro-elements electrically connected to a second signal conductor, the second signal conductor being electrically separate from the first signal conductor; and
a third group of micro-elements positioned between the first group and the second group, the third group of micro-elements being permanently disconnected from any signal conductors
wherein at least a majority of micro-elements of the array are spaced from adjacent micro-elements by a distance of half of a maximum operating wavelength of the array.
2. The transducer probe of claim 1 wherein each micro-element has a diameter between 25 microns and 200 microns.
3. The transducer probe of claim 1 wherein some of the micro-elements of the first group are differently sized than other micro-elements of the first group, wherein the size of a micro-element corresponds its fundamental operating frequency.
4. The transducer probe of claim 1 wherein the micro-elements of the first group are connected to a first ground conductor and the micro-elements of the second group are connected to a second ground conductor not electrically connected to the first ground conductor.
5. The transducer probe of claim 1 wherein the first group of micro-elements includes more micro-elements than the second group.
6. The transducer probe of claim 1 wherein the first group of micro-elements collectively forms a dedicated transmit element and the second group of micro-elements collectively forms a dedicated receive element.
7. The transducer probe of claim 1 further comprising a fourth group of micro-elements electrically connected to the first signal conductor by a switch that, when closed causes the fourth group to form a combined element with first group.
8. The transducer probe of claim 7 , wherein the micro-elements of the fourth group collectively surround the micro-elements of the first group.
9. The transducer probe of claim 7 , wherein the fourth group of micro-elements is adjacent to the first group of micro-elements.
10. The transducer probe of claim 7 , wherein the combined element has a different shape than the first group alone.
11. The transducer probe of claim 7 , wherein the combined element has a shape that is the same as a shape of the first group but a different size.