Imaging scan head apparatus having a fluid chamber with an inductive position sensor and a gearless voice-coil motor mechanism
Inventors
Dixon, Adam • Mauldin, Frank William • Owen, Kevin
Assignees
Publication Number
US-11612379-B2
Publication Date
2023-03-28
Expiration Date
2040-09-25
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Abstract
An ultrasound imaging scan head includes a fluid chamber including a gearless voice-coil motor therein. The voice-coil motor mechanism includes a rigid mechanical assembly, capable of moving with the fluid chamber, having one or more transducer elements and motor windings. Within the fluid chamber are motor magnets physically separated from the rigid mechanical assembly. The ultrasound imaging scan head further includes an inductive position sensor and internal bladder wherein the one or more transducer elements are capable of moving within the fluid chamber when a current is passed through the motor windings in a presence of a magnetic field generated by the one or more motor magnets.
Core Innovation
The invention provides an ultrasound imaging scan head apparatus featuring a compact, fluid-filled chamber that contains a gearless voice-coil motor mechanism, inductive position sensor, and an internal bladder. The gearless voice-coil motor mechanism consists of a rigid mechanical assembly supporting one or more ultrasound transducer elements and motor windings, which are capable of movement within the fluid chamber when actuated by current in the presence of a magnetic field generated by motor magnets separately housed within the same chamber.
The apparatus incorporates an inductive position sensor that can measure the position or angular displacement of the motor windings without requiring physical contact or optical encoders. This sensor operates by transmitting a radio frequency excitation through the motor windings, with the inductively coupled response enabling precise sensing of the rotor’s angular position, thereby integrating the angular position sensor function directly with the motor drive electronics.
An internal, compressible bladder serves to compensate for thermal expansion and contraction of the acoustic transmission fluid, reducing the risk of leaks and eliminating the need for gaskets or seals between major components. This allows for the entire mechanism, including optional ultrasound front-end electronics, to be integrated within the fluid chamber, resulting in a highly compact, lightweight, and leak-resistant ultrasound scan head suitable for multidimensional imaging.
Claims Coverage
The patent includes one independent claim covering five main inventive features.
Fluid chamber with integrated gearless voice-coil motor mechanism
The apparatus includes a fluid chamber that houses a gearless voice-coil motor mechanism. Within this chamber, a rigid mechanical assembly supports one or more transducer elements and motor windings, allowing motion inside the fluid chamber when activated. The motor magnets are physically separated from the rigid assembly yet still within the chamber.
Inductive position sensor for non-contact angular measurement
An inductive position sensor is included in the fluid chamber, capable of measuring the position of the motor windings by transmitting a radio frequency signal and detecting its inductive coupling. This configuration enables angular position measurement without a physical contact or optical encoder.
Internal compensating bladder for fluid expansion control
An internal bladder within the fluid chamber is used to compensate for or regulate the thermal expansion and compression of the acoustic transmission fluid, maintaining chamber integrity and pressure.
Incorporation of magnetic permeability componentry and soft magnetic materials
The apparatus contains parts with high magnetic permeability and soft magnetic materials to improve the efficiency and performance of the gearless voice-coil motor mechanism, increase the signal-to-noise ratio of the sensor, and provide partial or complete immunity from external magnetic interference.
Optional ultrasound front-end electronics within the fluid chamber
The scan head can include ultrasound front-end electronics inside the chamber to enhance compactness, reduce apparatus size, and lower the complexity and quantity of electrical interconnects.
These inventive features collectively enable a compact, efficient, and robust ultrasound imaging scan head, addressing size, weight, and leakage problems associated with prior designs.
Stated Advantages
The scan head mechanism is ultra-compact, lightweight, less prone to leaks, and low cost.
Absence of contact between transducer element, motor mechanism, and position sensor results in a very compact and lightweight design.
Eliminating gaskets or seal mechanisms between major components makes the device less susceptible to leaks.
Integration of all components within a small fluid chamber, including the bladder, increases compactness.
Documented Applications
Medical and clinical imaging applications, where the scan head delivers and collects ultrasound signals to generate images of a target region of the body.
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