Patent Application
20140031693
The present invention relates to portable ultrasonic imaging probes, and more specifically, to such probes including a transducer array, wherein such probes can be directly connected to a host computer, such as an off-the-shelf laptop computer, or the like.
Typically, ultrasound imaging systems include a hand-held probe that is connected by a cable to a relatively large and expensive piece of hardware that is dedicated to performing ultrasound signal processing and displaying ultrasound images. Such systems, because of their high cost, are typically only available in hospitals or in the offices of specialists, such as radiologists. Recently, there has been an interest in developing more portable ultrasound imaging systems that can be used with personal computers. Preferably, such a portable ultrasound probe can be used with an off-the-shelf host computer, such as a personal computer, and is inexpensive enough to provide ultrasound imaging capabilities to general practitioners and health clinics having limited financial resources.
In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific illustrative embodiments. It is to be understood that other embodiments may be utilized and that mechanical and electrical changes may be made. The following detailed description is, therefore, not to be taken in a limiting sense. In the description that follows, like numerals or reference designators will be used to refer to like parts or elements throughout. In addition, the first digit of a reference number identifies the drawing in which the reference number first appears.
As will be described in more detail below, in accordance with embodiments of the present invention, the probe 102 enables the host computer 112, via software running on the host computer 112, to form real-time ultrasonic images of a target 100 (e.g., human tissue or other materials) without the need for any additional internal or external electronics, power supply, or support devices. In certain embodiments, the probe 102 produces raw digitized data that is envelope detected ultrasound echo data from an array of ultrasound transducers in the probe 102, and transmits such raw data to the host computer 112. The raw digitized data can optionally also be logarithmically compressed, depending upon implementation.
In an embodiment, when the host computer 112 receives raw data via the passive interface cable 106 from the probe 102, the host computer 112 performs time gain compensation (TGC), gray-scale mapping, and scan conversion of the raw data using software that runs on the host computer 112, and displays the resultant video images. The probe does not include any moving mechanical parts, thereby reducing the complexity and cost of the probe 102 and increasing its reliability. The term “raw data”, as used herein, refers to ultrasound imaging data that has not yet been time gain compensated, gray-scale mapped and scan converted. As described below, such raw data is included in the digital signal that is transferred from the probe 102 to the host computer 112.
As shown in
The article “A New Time-Gain Correction Method for Standard B-Mode Ultrasound Imaging”, by William D. Richard, IEEE Transactions of Medical Imaging, Vol. 8, No. 3, pp. 283-285, September 1989, which is incorporated herein by reference, describes an exemplary time gain correction technique that can be performed by the host computer 112. The article “Real-Time Ultrasonic Scan Conversation via Linear Interpolation of Oversampled Vectors,” Ultrasonic Imaging, Vol. 16, pp. 109-123, April 1994, which is incorporated herein by reference, describes an exemplary scan conversion technique that can be performed by the host computer 112. These are just exemplary details of the host computer 112, which are not meant to be limiting.
The passive interface cable 106 includes at least one data line over which data is carried, and at least one power line to provide power to a peripheral device, which in this case is the ultrasonic imaging probe 102. For example, where the passive interface cable 106 is a USB 2.0 cable, one wire of the cable provides about 5V at about ½ Amp. In alternative embodiments, the passive interface cable 106 is a Firewire cable, which also includes a power wire. Other types of passive interface cable can be used if desired. However, as mentioned above, it is preferred that the passive interface cable 106 is a standard off-the-shelf cable that can interface with an off-the-shelf interface IC. The term passive as used herein refers to a cable that does not regenerate signals or process them in any way. In an alternative embodiment, the probe 102 and the host computer 112 communicate wirelessly, and the probe 102 includes a battery that is used to power the components within the probe.
In accordance with certain embodiments, the data samples produced by the ultrasound imaging probe 102 of the present invention are transmitted by the probe 102 across the interface cable 106 to the host computer 112. In a specific embodiment, this is accomplished when the host computer 112 reads the data temporarily stored in the buffers of the interface IC 204. The host computer 112 runs software that enables the host to perform time gain compensation (TGC), gray-scale mapping, and scan conversion of the data received from the probe 102. The host computer generates and displays the resultant ultrasound video images. Advantageously, the host computer 112 does not need to perform electronic beamforming or other equivalent image processing, thereby simplifying the software that the host computer 112 runs.
The host computer 112 can use the digital data received from the ultrasound device 102 to provide any available type of ultrasound imaging mode can be used by the host computer 112 to display the ultrasound images, including, but not limited to A-mode, B-mode, M-mode, etc. For example, in B-mode, the host computer 112 performs know scan conversion such that the brightness of a pixel is based on the intensity of the echo return.
A benefit of specific embodiments of the present invention is that only digital signals are transmitted from the probe 102 to the host computer 112, thereby providing for better signal-to-noise ratio than if analog signals were transmitted from the probe 102 to the host computer 112, or to some intermediate apparatus between the host computer and the probe. Another benefit of specific embodiments of the present invention is that the probe 102 can be used with a standard off-the-shelf passive interface cable.
A further benefit of specific embodiments of the present invention is that the probe 102 does not perform any time gain compensation, gray-scale mapping and scan conversion, thereby significantly decreasing the complexity, power requirements and cost of the probe 102. Conventionally, functions such as scan conversion, time gain correction (also known as time gain compensation) and gray-scale mapping are performed by a machine that is dedicated to obtaining ultrasound images, or by an intermediate device that is located between the probe and host computer. In contrast, in embodiments of the present invention, software running on the host computer 112 is used to perform these functions, thereby reducing the complexity and cost of the portable ultrasonic imaging probe 102.
In accordance with an embodiment illustrated in
The probe 102 is also shown as including a digital control and processing block 206, an analog to digital converter (ADC) 208 and a high voltage power supply (HVPS) 250. The HVPS 250 provides power to a high voltage (HV) pulser 224. Additionally, the probe 102 is shown as including a micromachined ultrasound transducer (MUT) array 220, which includes individually controllable MUT elements 221, which are discussed in additional detail below. A transmit and receive (Tx/Rx) controller 240 accesses vector configuration and timing data stored within a memory 230 in order to controls transmit (Tx) switches 222 and receive (Rx) switches 216, to thereby control the operation of the MUT elements 221 of the MUT array 220, as described in additional detail below. In certain embodiments, such vector configuration and timing data is stored within a look-up table (LUT) within the memory 230.
The probe 102 also includes analog summing, amplification and processing circuitry 215. In accordance with an embodiment, the analog summing, amplification and processing circuitry 215 includes summing resistors 214 and a summing amplifier 212, which are discussed in more detail with reference to
The RF signal output by the analog signal processing block 210 is digitized by the ADC 208. The ADC 208 samples the RF signal (e.g., at 30 or 48 MHz), to thereby digitize the signal, and provides the digitized signal to the digital control and processing block 210. The digital control and processing block 206 could be implemented, e.g., using a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), an application specific integrated circuit (ASIC) or some other circuitry. The digital control and processing clock 206 control functions and timing of the hardware in the probe, and depending upon implementation, can also perform digital signal processing of the digital signal output by the ADC 208. For example, the digital control and processing block 206 can perform logarithmic compression, as was mentioned above. The digital control and processing clock 206 also controls the Tx/Rx controller 240.
The Tx/Rx controller 240, which can be implemented using an FPGA, an ASIC or some other circuitry, controls the Tx switches 222 so that a selected set of the MUTs transmit ultrasonic pulses generated by a high voltage (HV) pulser 224. The host computer 112, through the passive interface cable 106, and the interface IC 204 can control the amplitude, frequency and duration of the pulses output by the HV pulser 224. For example, the host computer 112 can write vector configuration and timing data to the memory 230. Additionally, the host computer 112 can send instructions to the probe 102 that cause the probe 102 to select, from the memory 230, specific transmit and receive vector control and timing data used to control transmission and reception of ultrasonic pulses.
The HV pulser 224 is powered by the HVPS 250, which generates the high voltage potential(s) required by the HV pulser 224 from a lower voltage (e.g., 5V) received via the passive interface cable 106. Depending upon implementation, the HV pulser 224 can produce unipolar pulses, or bipolar pulses. Unipolar pulses can be, e.g., high voltage pulses that are as large as 100V. Where the HV pulser 224 produces bipolar pulses, the HV pulser 224 may produce, e.g., both positive and negative high voltage pulses that can be as large as +/−100V. In such embodiments, the HVPS 250 can provide up to +/−100V supply rails to the HV pulser 224. Exemplary details of an HVPS, which can be used to implement the HVPS 250, are shown in and described with reference to FIG. 4 of U.S. Patent Publication No. 2007/0239019, which U.S. Patent Publication is incorporated herein by reference in its entirety. Alternative high voltage power supplies known in the art may also used as HVPS 250.
The probe 102 can also include a linear regulator IC (now shown) with integrated power switches and low quiescent current requirements designed for USB applications. For example, such a linear regular IC can produce a 3.3V digital supply and a 3.3V analog voltage supply, which are used to provide power to the various circuits/blocks within the probe 102. For example, a 3.3V digital supply can power the interface IC 204 and the digital control and processing block 206; and a 3.3V analog supply can power the summing amplifier 212 and the analog signal processing circuitry 210. An exemplary IC that can be used for the linear regulator IC is the TPS2148 3.3-V LDO and Dual Switch for USB Peripheral Power Management IC, available from Texas Instruments of Dallas, Tx.
Preferably, the probe 102 is configured as a single channel architecture, which means that only a single ADC 208 is required, and only a single data signal is transmitted from the probe 102 to the host 112 at any given time. However, in alternative embodiments, a multiple channel architecture that includes multiple ADCs can be implemented. Unless stated otherwise, the embodiments described herein include a single channel architecture. Another benefit of specific embodiments of the present invention is that the MUT array 220 is in close proximity to (i.e., within the same housing as) the analog summing, amplifying and processing circuitry 215 and the ADC 208 (see
As mentioned above, the portable ultrasound imaging probe 102 includes an array of ultrasound transducers, which includes numerous transducers. In a preferred embodiment, the portable ultrasound imaging probe 102 includes a micromachined ultrasound transducer (MUT) array 220, which includes numerous MUTs 221, each of which can be referred to as an MUT element (or simply as an MUT). Each MUT element can include a single MUT cell, or multiple MUT cells hardwired together. Such a MUT array 220, which can also be referred to as an array of MUTs, is an example of a MEMS based transducer, since the MUTs are examples of micro-electro-mechanical systems (MEMS). A MUT is one example of an ultrasound transducer. However, the principles of the present invention are also applicable to arrays of ultrasound transducers and ultrasound transducers other than MUTs. Thus, although the following description refers to MUTs, alternative ultrasound transducers and transducer arrays can be used in place of the MUTs and MUT arrays described below.
Each MUT cell can be a capacitive MUT (cMUT) cell or a piezoelectric MUT (pMUT) cell, but is not limited thereto. Such cells typically include a membrane (often referred to as a diaphragm) and two or more electrodes. For transmission, the electrodes and membrane are used to modulate a capacitive charge that vibrates the membrane and thereby transmits a sound wave. For reception, the electrodes and membrane are used to convert the sound vibration of a received ultrasound signal into a modulated capacitance. More specifically, when an AC signal is applied across the electrodes, the MUT generates ultrasonic waves in the medium of interest to thereby function as a transmitter. When ultrasonic waves are applied to the membrane of a MUT, the MUT generates an alternating signal as the capacitance of the MUT is varied to thereby function as a receiver of ultrasonic waves.
Each MUT element can simply be referred to as an MUT, and a plurality of MUT elements can simply be referred to as MUTs. Preferably, the MUT array 220 is encased in material that has the proper acoustic impedance to be matched with acoustic impedance of human tissue.
Advantageously, MUTs can be made using semiconductor fabrication processes, such as microfabrication processes generally referred to as “micromachining” Micromachining is the formation of microscopic structures using patterning, deposition and/or etching. Patterning generally includes lithography, which can be performed using projection-aligners or wafer-steppers, but is not limited thereto. Deposition can be physical vapor deposition (PVD), chemical vapor deposition (CVD), low-pressure chemical vapor deposition (LPCVD), or plasma chemical vapor deposition (PECVD), but is not limited thereto. Etching can include wet-chemical etching, plasma-etching, ion-milling, sputter-etching or laser-etching, but is not limited thereto.
Micromachining is typically performed on substrates or wafers made of silicon, glass, sapphire or ceramic. Such substrates or wafers are generally very flat and smooth and have lateral dimensions in inches. They are usually processed as groups in cassettes as they travel from process tool to process tool. Each substrate can advantageously (but not necessarily) incorporate numerous copies of a product. Micromachining can include the use of conventional or known micromachinable materials including silicon, sapphire, glass materials of all types, polymers (such as polyimide), polysilicon, silicon nitride, silicon oxynitride, thin film metals such as aluminum alloys, copper alloys and tungsten, spin-on-glasses (SOGs), implantable or diffused dopants and grown films such as silicon oxides and nitrides, but is not limited thereto.
In accordance with an embodiment, the MUT array 220 includes M rows×N columns of transducer elements, with the MUTs 221 being illustrated as small circles in
Each of the MUTs 221 can have a circumferential shape that is circular, as shown. Each MUT 221 can be, e.g., about 50 micrometers in diameter, but is not limited thereto. The distance from the edge of one MUT 221 to its closest adjacent MUT 221 can be, e.g., about 70 micrometers, but is not limited thereto. Alternatively, each of the MUTs can have another circumferential shape, including, but not limited to, square or hexagonal. In accordance with certain embodiments, the Tx MUTs 223 and the Rx MUTs 225 are structurally the same. In such embodiments, the only difference between a Tx MUT 223 and an Rx MUT 225 is how the MUT is connected to other circuitry and used. In other embodiments, the Tx MUTs 223 can be structurally different from the Rx MUTs 225. In alternative embodiments, each of MUTs 221 may be replaced with conventional ultrasound transducers which may be square or circular in shape (see, e.g.
All of the rows and columns can be inline with one another, as shown in
As will be described in further detail below, at any given time, a set of the Tx MUTs 223 can be selected for transmitting ultrasonic pulses, and a set of the Rx MUTs 225 can be selected for receiving echo pulses. For example, sets of Tx MUTs 223 that collectively make up rings can be used to form a quasi-annular array transducer, as will be described below with reference to
Selected Tx MUTs 223 transmit ultrasonic pulses into the target region being examined, and selected Rx MUTs 225 receive reflected ultrasonic pulses (i.e., “echo pulses”) returning from the region. When transmitting, the selected Tx MUTs 223 are excited to high-frequency oscillation by the pulses emitted by the HV pulser 224, thereby generating ultrasound pulses that can be directed at a target region/object to be imaged.
These ultrasound pulses (also referred to as ultrasonic pulses) produced by the selected Tx MUTs 223 are echoed back towards the selected Rx MUTs 225 from some point within the target region/object, e.g., at boundary layers between two media with differing acoustic impedances. The echo pulses received by the selected Rx MUTs 225 are converted into corresponding low-level electrical input signals (i.e., the “echo signals”) that are provided to the analog summing, amplification and processing circuitry 215. In specific embodiments, to receive echo pulses, the Rx switches 216 selectively connect a set of the Rx MUTs 225 to summing resistors 214, which are used to sum the echo pulses at the input of a summing amplifier 212.
Advantageously, in certain embodiments, the vectors may be uploaded to memory (look-up-table) 230 from Host Computer 112 in order to upgrade probe 102 or provide a set of vectors suitable for a particular imaging application. For example different vectors can be provided for imaging different portions of the human body, different tissues, or different depths depending on the application. A user can select the appropriate application (imaging purpose) in the host computer 112 which can then transfer an appropriate vector set to memory 230 over passive interface cable 106 prior to imaging. Alternatively memory 230 can include a plurality of vector sets suitable for different applications and the user can select which of those vector sets is used by Tx/Rx Controller 215 in a particular imaging session by input to host computer 112 or using an interface/switch/multiposition switch on probe housing 103. After download or selection of a pre-existing vector set in memory 230, the vector set can be used by Tx/Rx Controller 215 to configure Tx switches 222 and Rx switches 216 to cause Tx MUTS 223 and Rx MUTS 225 to transmit and receive ultrasound pulses in accordance with the downloaded vectors suitable for the intended application.
Note that, as previously discussed, single channel architecture is used. Accordingly, the Rx switches 216 (or Tx/Rx) switches connect a plurality of selected MUTS 225 to analog summing, amplification and signal processing circuitry 215. Note that there are a plurality of summing resistors 214 in order that they may be connected to a selected plurality of Rx MUTS 225. Analog summing, amplification and signal processing circuitry 215 is configured to combine the plurality of echo signals produced by the plurality of the ultrasound transducers 225 into a single analog echo signal. This can be achieved using summing amplifier 212. A single analog-to-digital converter 208 (ADC) then converts the analog echo signal into a single digital echo signal for transmission to a host computer that can perform digital processing of the digital echo signal in order to display an ultrasound image.
Transducer array 260 is preferably planar in shape i.e. all of transducers 262 lay in a single flat plane (not curved). Moreover, in preferred embodiments no lens or other beam forming device is placed over transducer array 260. Accordingly, similar or identical ultrasound beams can be produced by similar groups of transducers 262 at different locations in transducer array 260.
Transducers 262 can be made using conventional technology known in the art and may be, for example, piezo-electric transducers or capacitive transducers. In an embodiment ultrasound transducers 262 are substantially rectangular piezoelectric transducers approximately 5 mm by 0.3 mm in size. A set of 16 adjacent transducers acting together form a substantially square ultrasound source.
As shown in
Note that, as previously discussed, single channel architecture is used in combination with transducer array 260. Accordingly, the Tx/Rx switches 266 (or Rx switches 216 in an alternative embodiment) connect the plurality of selected transducers 262 to analog summing, amplification and signal processing circuitry 215 which is configured to combine echo signals produced by a plurality of the ultrasound transducers 262 into a single analog echo signal. A single analog-to-digital converter (ADC) then converts the analog echo signal into a digital echo signal for transmission to a host computer that can perform digital processing of the digital echo signal in order to display an ultrasound image.
The Tx/Rx switches 266 can be used to connect a selected set of the transducers 262 to either the HV pulser 224, or the analog summing, amplification and processing circuitry 215, depending on whether the transducers 262 are to be used for transmitting or receiving ultrasound pulses at a particular time. When a high voltage pulse is produced by the HV pulser 224, the Tx/Rx switches automatically block the high voltage from damaging the analog summing, amplification and processing circuitry 215. When the HV pulser 224 is not producing a pulse, the Tx/Rx switches disconnect a selected set of transducers 262 from the pulser 224, and instead connect a selected set of transducers 262 to the analog summing, amplification and processing circuitry 215. Note that Tx/Rx switches 266 may also be used in combination with MUT array 220 (see, e.g.
By controlling the Tx switches 222 to select different groups of Tx MUTS 223 at different times, the transmitting group of transducers forms an ultrasound transmitter which effectively changes shape and/or size and/or position over time. As shown in
By controlling the Rx switches 216 to select different groups of Rx MUTS 225 at different times, the receiving group of transducers forms an ultrasound receiver which effectively changes shape, size, or position within the array of transducers over time. As shown in
Tx/Rx Controller 240 controls Tx switches 222 and Rx switches 216 to select different groups of Tx MUTs 223 and Rx MUTS 225 at different times for sending and receiving ultrasound transducers thereby allowing the MUT Array 220 to emulate an ultrasound receiver and ultrasound transmitter which effectively changes in shape, size, or position within the array of transducers over time. While the Tx MUT and Rx MUT vectors shown in
Advantageously, the MUT array 220 and the circuitry used to select sets of the MUTs can provide a continuously variable aperture annular array. More specifically, such circuitry can be used to activate sets of MUTs in such a way that the active area of annular arrays will continuously shift in order to form ultrasound beams with variable focal points. In other words, the MUT array 220 can be used to perform beam forming and aperture control for each of a plurality of different MUT vectors. Advantageously, beam shapes and aperture shapes and sizes can be optimized for both transmit and receive signals.
In accordance with certain embodiments of the present invention, preprogrammed vector configuration and timing data that enables the various annular rings of Tx MUTs 223 shown in
By controlling the Tx/Rx switches 266 to select different groups of ultrasound transducers 262 (shaded) at different times, the receiving group of transducers forms an ultrasound receiver which effectively changes shape, size, or position within the array of transducers 260 over time. As shown in
In
Tx/Rx Controller 240 controls Tx/Rx switches 266 (see
As described above with respect to the figures, in an embodiment, the present invention provides a portable ultrasonic imaging probe 102 that is adapted to connect to a host computer 112 via a passive interface cable 106. The portable ultrasound imaging probe 106 includes a probe head 105 including an array of ultrasound transducers, for example MUT Array 220. The array may comprise one or more parallel rows of ultrasound transducers, or a different shaped distribution of a plurality of ultrasound transducers. The ultrasound transducers may be, for example, micromachined ultrasound transducers MUTS 221 or other ultrasound transducers known in the art.
The portable ultrasonic imaging probe 102 also includes a pulse circuit, for example, a high voltage (HV) pulser 224 adapted to energize two or more transducers to emit ultrasound. The portable ultrasonic imaging probe 102 also includes analog processing circuitry 215, including for example summing amplifier 212, and summing resistors 214, configured to process electrical signals caused by ultrasound pulses received by two or more ultrasound transducers into an analog echo signal. One or more analog-to-digital converters (e.g. ADC 208) converts the analog echo signal, output by the analog summing, amplification and signal processing circuitry, to a digital echo signal, and an interface circuit 204 transfers the digital echo signal across a passive interface cable to a host computer that can perform digital processing of the digital echo signal in order to display an ultrasound image.
The portable ultrasonic imaging probe 102 also includes a transmit/receive controller 215 connected to a plurality of transmit (Tx) switches 222 and a plurality of receive (Rx) switches 216 wherein the transmit/receive controller 215 selects which of said ultrasound transducers are in transmitting group and which of said ultrasound transducers are in the receiving group at any point in time. The transmit/receive controller 215 configures the plurality of transmit (Tx) switches 222 to connect a transmitting group of the ultrasound transducers to the (HV) pulser 224. The transmit/receive controller 215 also configures a plurality of receive (Rx) switches 2′6 to connect a receiving group of the ultrasound transducers to the analog summing, amplification and signal processing circuitry 215.
The portable ultrasonic imaging probe 102 operates such that which ultrasound transducers of the ultrasound transducer array are part of the receiving group and which are part of the receiving group is configurable and can be changed over time under the control of transmit/receive controller 215 in response. Transmit and receive (Tx/Rx) controller 240 accesses vector configuration and timing data stored within a memory 230 to identify which transducers should be activated for transmitting (transmitting group) or receiving ultrasound pulses (receiving group) and at what time.
In accordance with the vector configuration and timing data the transmitting group includes a first plurality of transducers at a first time, a second plurality of transducers different than the first plurality at a second time, and a third plurality of transducers different than the first plurality and the second plurality a third time. The configurable transmitting group functions as a configurable ultrasound transmitter which can change in shape, size or position within the transducer array over time. This allows, for example the ultrasound imaging probe 102 to: emit a focused ultrasound beam; change the depth or focus or position of focus of the ultrasound beam; perform ultrasound beam forming; scan the ultrasound beam without moving the head 105; and/or form a variable aperture ultrasound transmitter; and use configurable aperture control.
In accordance with the vector configuration and timing data the receiving group includes a first plurality of transducers at a first time, a second plurality of transducers different than the first plurality at a second time, and a third plurality of transducers different than the first plurality and the second plurality a third time. The configurable receiving group functions as a configurable ultrasound receiver which can change in shape, size or position within the transducer array over time. This allows, for example the ultrasound imaging probe 102 to: change the size, shape, or position of the configurable ultrasound receiver over time (in relation, for example, to the timing of the emission of ultrasound pulses). The receiving group can be selected in such a way that the active area of receiving transducers can be configured and changed over a number of sampling cycles in order to optimize the resolution of the received signal from different depths, different tissues, and in different applications.
In alternative embodiments, rather than having half the MUTs 221 dedicated to functioning as Tx MUTs 223, and half the MUTs 221 dedicating to functioning as Rx MUTs 225, each of the MUTs 221 of the MUT array 220 can be capable of being used as either an Rx MUT 223 or a Tx MUT 225. In such alternative embodiments, transmit/receive (Tx/Rx) switches (not shown) can be used in place of the Tx switches 222 and the Rx switches 216. The Tx/Rx switches can be used to connect a selected set of the MUTs 221 to either the HV pulser 224 or the analog summing, amplification and processing circuitry 215 depending on whether the MUTs 221 are to be used for transmitting or receiving ultrasound pulses at a particular time. When a high voltage pulse is produced by the HV pulser 224, the Tx/Rx switches would automatically block the high voltage from damaging the analog summing, amplification and processing circuitry 215. When the HV pulser 224 is not producing a pulse, the Tx/Rx switches disconnect a selected set of MUTs 221 from the HV pulser 224, and instead connect a selected set of MUTs to the analog summing, amplification and processing circuitry 215. However, Tx/Rx switches are relatively expensive compared to switches required to perform only one of the Tx switching and Rx switching functions. Accordingly, the aforementioned embodiments where certain MUTs 221 are dedicated to transmission, and other MUTs 221 are dedicated to reception, such a configuration may be preferable where it is desirable to eliminate the need for expensive Tx/Rx switches.
The foregoing description of preferred embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations will be apparent to one of ordinary skill in the relevant arts. The above mentioned part numbers are exemplary, and are not meant to be limiting. Accordingly, other parts can be substituted for those mentioned above.
The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications that are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.
This application claims the benefit of priority to U.S. Provisional Patent Application No. 61/676,193 filed Jul. 26, 2012 entitled “PORTABLE ULTRASOUND IMAGING PROBE INCLUDING MEMS BASED TRANSDUCER ARRAY” which application is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61676193 | Jul 2012 | US |
