Multilayer phase modulation acoustic lens

Abstract

An ultrasound probe lens, the ultrasound probe lens comprising: a lens body comprising a solid material extending outwardly from an optical lens axis to a periphery; an inner surface of the lens body; and an outer surface of the lens body. The thickness of the lens body measured from the inner surface to the outer surface varies from the optical lens axis to the periphery such that the lens body is configured with an inner optical profile and an outer optical profile to phase modulate ultrasonic waves incident on the lens body to reduce reverberation.

Description

Technical Field

[0001] Multilayer phase-modulated acoustic lens. Background Art

[0002] In recent years, ultrasound probes have increasingly used hard shell lenses consisting of an outer rigid shell and an inner layer of a softer elastomer facing the transducer array. These hard shell lenses have shown advantages such as increased improved chemical barriers, ruggedness and reliability, and reduced high-frequency acoustic losses. However, the use of hard shell lenses can result in an increase in the internal reflectivity (echo) of the signal within the probe (reverberation), which can produce artifacts in ultrasound images. Summary of the invention

[0003] In an embodiment, the present disclosure relates to an ultrasound probe lens, the ultrasound probe lens comprising: a lens body, the lens body comprising a solid material extending outward from an optical lens axis to a periphery; an inner surface of the lens body; and an outer surface of the lens body. The thickness of the lens body measured from the inner surface to the outer surface varies from the optical lens axis to the periphery, so that the lens body is configured with an inner optical profile and an outer optical profile to phase modulate an ultrasonic wave incident on the lens body, thereby reducing reverberation.

[0004] In an embodiment, the outer surface of the lens body includes a curved shape or a flat shape that changes the thickness of the lens body.

[0005] In an embodiment, the inner surface of the lens body includes a curved shape or a wedge shape that changes the thickness of the lens body.

[0006] In an embodiment, the interior surface of the lens body comprises a customized shape that alternates between increasing and decreasing the thickness of the lens body.

[0007] In an embodiment, the thickness of the lens body increases from the optical lens axis to the periphery of the lens body.

[0008] In an embodiment, the thickness of the lens body decreases from the optical lens axis to the periphery of the lens body.

[0009] In an embodiment, the lens body includes a dimension from an optical lens axis to a periphery to reduce reverberation of ultrasound waves in a field of view of a 1-dimensional (1D) ultrasound transducer.

[0010] In an embodiment, the lens body includes a dimension from an optical lens axis to a periphery to reduce reverberation of ultrasound waves in a field of view of a 2-dimensional (2D) ultrasound transducer.

[0011] In an embodiment, the inner surface of the lens body includes a texture configured to reduce reverberation of ultrasound waves.

[0012] In an embodiment, the solid material between the inner surface of the lens body and the outer surface of the lens body is configured to create an internal optical profile to reduce reverberation of the ultrasonic waves.

[0013] In an embodiment, the present disclosure relates to an ultrasound probe, the ultrasound probe comprising: a lens body, the lens body comprising a solid material extending outward from an optical lens axis to a periphery; and a transducer, the transducer being configured to transmit ultrasonic waves through the lens body, receive reflected ultrasonic waves through the lens body, and convert the received reflected ultrasonic waves into electrical signals for further processing. The thickness of the lens body measured from the inner surface of the lens body to the outer surface of the lens body varies from the optical lens axis to the periphery, so that the lens body is configured with an inner optical profile and an outer optical profile to phase modulate the received reflected ultrasonic waves incident on the lens body, thereby reducing reverberation.

[0014] In an embodiment, the outer surface of the lens body includes a curved shape or a flat shape that changes the thickness of the lens body.

[0015] In an embodiment, the inner surface of the lens body includes a curved shape or a wedge shape that changes the thickness of the lens body.

[0016] In an embodiment, the interior surface of the lens body comprises a customized shape that alternates between increasing and decreasing the thickness of the lens body.

[0017] In an embodiment, the thickness of the lens body increases from the optical lens axis to the periphery of the lens body.

[0018] In an embodiment, the thickness of the lens body decreases from the optical lens axis to the periphery of the lens body.

[0019] In an embodiment, the lens body includes a dimension from the optical lens axis to the periphery to reduce reverberation of reflected ultrasound waves received in the field of view of a 1-dimensional (1D) ultrasound transducer or a 2-dimensional (2D) ultrasound transducer.

[0020] In an embodiment, the further processing includes processing the electrical signal to compensate for phase modulation of the received reflected ultrasonic wave caused by the lens.

[0021] In an embodiment, the interior surface of the lens body includes a texture configured to reduce reverberation of received reflected ultrasonic waves.

[0022] In an embodiment, the solid material between the inner surface of the lens body and the outer surface of the lens body is configured to create an internal optical profile to reduce reverberation of received reflected ultrasonic waves. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order that the manner in which the above-mentioned features of the present disclosure can be understood in detail, a more particular description of the present disclosure, briefly summarized above, may be made by reference to exemplary embodiments, some of which are shown in the accompanying drawings. However, it should be noted that the accompanying drawings illustrate only exemplary embodiments of the present disclosure and therefore should not be considered as limiting the scope of the present disclosure, as the present disclosure may allow other equally effective exemplary embodiments.

[0024] Figure 1A A block diagram of an ultrasound machine according to an exemplary embodiment of the present disclosure is shown.

[0025] Figure 1B A block diagram of the hardware of an ultrasound machine according to an exemplary embodiment of the present disclosure is shown.

[0026] Figure 2 A flow chart illustrating the operation of an ultrasound machine according to an exemplary embodiment of the present disclosure.

[0027] Figure 3A A data graph showing signal attenuation for various acoustic lens profiles according to an exemplary embodiment of the present disclosure.

[0028] Figure 3B A data graph showing signal attenuation for various acoustic lens profiles according to an exemplary embodiment of the present disclosure.

[0029] Figure 4A Shown are elevation views of various acoustic lens profiles for a 2D probe according to exemplary embodiments of the present disclosure.

[0030] Figure 4B Azimuth views of various acoustic lens profiles for a 2D probe are shown according to an exemplary embodiment of the present disclosure.

[0031] Figure 4C Shown are elevation views of various acoustic lens profiles for a ID probe according to an exemplary embodiment of the present disclosure.

[0032] Figure 5 A flow chart of manufacturing an acoustic lens and an ultrasound probe according to an exemplary embodiment of the present disclosure is shown.

[0033] Figure 6 A lens profile of an acoustic lens having a temporary lens profile according to an exemplary embodiment of the present disclosure is shown.

[0034] Figure 7 A flow chart of manufacturing an acoustic lens and an ultrasound probe having a temporary lens profile according to an exemplary embodiment of the present disclosure is shown.

[0035] Figure 8A block diagram showing a transducer array and corresponding time delays due to acoustic lensing according to an exemplary embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0036] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of the parts and steps, numerical expressions and numerical values ​​set forth in these exemplary embodiments do not limit the scope of the present disclosure unless otherwise specifically stated. The following description of at least one exemplary embodiment is essentially only illustrative and is by no means intended to limit the present disclosure, its application or its use. The technology, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but are intended to be a part of this specification in appropriate circumstances. In all examples described and discussed herein, any specific value should be interpreted as illustrative and non-restrictive. Therefore, other exemplary embodiments may have different values. Note that in the following figures, similar reference numerals and letters refer to similar items, and therefore once an item is defined in an accompanying drawing, it may not be necessary to further discuss the item for the following accompanying drawings. Below, exemplary embodiments will be described with reference to the accompanying drawings.

[0037] The ultrasound machine utilizes an ultrasound probe including an array of transducers having a field of view for transmitting acoustic signals, which are reflected (echoes) from anatomical structures and received and processed to construct an image of the anatomical structure. Specifically, the ultrasound probe may include a 1-dimensional (1D) or 2-dimensional (2D) array of piezoelectric elements, which are driven by electrical signals to vibrate to produce the emitted sound waves. The piezoelectric element array then receives the reflections (echoes) of the emitted sound waves. Upon receiving the echoes, the piezoelectric element array converts the sound waves into electrical signals, which are then processed by the ultrasound machine to construct an image of the anatomical structure. The image can provide an image depicting both the distance of the anatomical structure to the transducer and the density of the anatomical structure. The distance from the ultrasound probe to the anatomical structure is determined by the time it takes for the emitted sound waves to be reflected (echoes) and received by the ultrasound probe. The density of the anatomical structure can be determined by the intensity of the received reflected acoustic signals.

[0038] In the case of a hard shell ultrasound probe lens, acoustic reverberation may occur in the ultrasound probe when the received reflected waves bounce back and forth between the acoustic lens and other internal structures within the probe itself (e.g., the probe shell, etc.). The methods, devices, and systems disclosed herein overcome the limitations of existing ultrasound acoustic lenses by introducing a lens body with an optical profile that introduces phase modulation to the echo so that any reverberation signals are deconstructively combined with each other to produce attenuated reverberation within the probe. For example, the lens body can achieve this phase modulation and attenuated reverberation by using at least one of a non-uniform lens thickness and a textured lens surface. Signal processing techniques (such as beamforming) may also be implemented to compensate for the phase modulation introduced by the acoustic lens to maintain image accuracy. The transmitted and received waves are effectively realigned to avoid any degradation of image quality due to phase modulation, so that the waves reflected only in the probe are effectively attenuated to reduce reverberation. These features are described in more detail below.

[0039] Benefits of the disclosed methods, devices, and systems described herein include, but are not limited to, attenuating reverberation in ultrasound probes, thereby reducing unwanted artifacts and improving image quality (e.g., improving image contrast, reducing artifacts, etc.) Note that while the lens solution is described herein with respect to use in ultrasound probes, the lens solution will also be applicable to any other related acoustic applications (e.g., sonar applications, etc.) where reverberation is a problem.

[0040] Figure 1A A block diagram 100 of an ultrasound machine including a computer 102 and an ultrasound probe 104 is shown. The computer 102 may be a computer (e.g., a personal computer) executing software for controlling the operation of the ultrasound probe 104 and for converting and processing received sound waves to generate and display the resulting ultrasound image. The ultrasound probe 104 may be any type of ultrasound probe (e.g., linear, curvilinear, phased array, 1D, 2D, etc.) including internal components housed in a housing 104E. These internal components may include an acoustic lens 104A, an acoustic matching layer 104B, an acoustic transducer 104C, a backing material 104D, and a circuit 104F. Note that in another example, the computer 102 may be a handheld device (e.g., a smart phone, a tablet computer, etc.) for processing converted sound waves to generate and display the resulting ultrasound image. In yet another example, the ultrasound probe 104 may be a standalone device having a processor and supporting hardware / software for converting and processing received sound waves to generate and display the resulting ultrasound image.

[0041] During operation, the computer 102 executing the software controls the circuit 104F in the transmission mode so as to drive the transducer 104C to vibrate and transmit sound waves from the probe. The signal is transmitted through the acoustic matching layer 104B and the acoustic lens 104A. After transmitting the sound wave, the computer 102 controls the circuit 104F in the receiving mode so as to turn off the transducer 104C and wait for the reflected sound wave (echo). The echo (e.g., the echo reflected from the anatomical structure) enters the probe via the acoustic lens 104A and the acoustic matching layer 104B before being received by the transducer 104C. Each part of the transducer array 104C vibrates according to the part of the echo incident on the transducer array element, thereby generating an electrical signal with an amplitude proportional to the intensity of the echo. These electrical signals are then transmitted back from the circuit 104F to the computer 102 for further processing. For example, the computer 102 creates an image (e.g., a 2-dimensional image) based on the timing and intensity between the transmitted / received waves. The ultrasound image is then displayed to the ultrasound technician.

[0042] Figure 1B A block diagram 106 of the hardware of the computer 102 is shown. In this example, the computer 102 may include a processor 106A, a memory 106B, and an ultrasound probe input / output (I / O) circuit 106C. During operation, the processor 106A executes computer software stored in the memory 106B. The computer software may be software for controlling an ultrasound probe and for creating an ultrasound image. For example, when executing the ultrasound software, the processor 106A may send instructions (e.g., electrical signals, etc.) to the ultrasound probe via the ultrasound probe I / O circuit 106C (e.g., an electrical port for communicating with the ultrasound probe, etc.). These control signals may control the ultrasound probe to transmit and receive ultrasound waves, which are then converted into electrical signals, which are sent back to the processor 106A via the ultrasound probe I / O circuit 106C for further processing to produce an ultrasound image.

[0043] For the sake of clarity, Figure 2A flowchart 200 of the operation of an ultrasound machine is shown. In step 202, the computer 102 controls the ultrasound probe 104 to transmit ultrasound waves. In step 204, the ultrasound probe 104 receives echoes reflected from a target object (e.g., an anatomical structure). In step 206, the ultrasound probe 104 converts the received echoes into electrical signals. For example, each transducer element in the array will vibrate with an intensity related to the intensity of the portion of the sound wave incident on the transducer element. In step 208, the ultrasound probe 104 sends the electrical signal to the computer 102 for further processing. In step 210, the computer 102 processes the electrical signal according to ultrasound software to generate an ultrasound image, which can be grayscale or color. Again, the processing may include analyzing the timing / intensity of the electrical signal and correlating the timing / intensity with the distance / density of the anatomical features displayed in the image with different contrast and / or color.

[0044] As described above, acoustic reverberation may occur within an ultrasound probe when echoes bounce back and forth, for example, between the acoustic lens and other internal structures within the probe, thereby producing unwanted artifacts that degrade image quality. The methods, devices, and systems disclosed herein overcome the limitations of existing ultrasound acoustic lenses by introducing a lens body having an optical profile (an inner (i.e., internal) optical profile and an outer (i.e., external) optical profile) that introduces phase modulation (time delay) to different portions of the echoes so that any reverberant waves deconstructively combine with each other to produce an attenuated reverberation.

[0045] For example, Figure 3A A data graph 300 of signal attenuation for various acoustic lens profiles is shown. Profile 304A is an acoustic lens profile for a lens having a uniform thickness between the inner and outer surfaces as the lens extends from the optical lens axis (0 mm azimuth) to the periphery. Profile 304A can be used as a reference profile because it does not introduce phase modulation (different time delays) to the echo. In contrast, profile 304B is an acoustic lens profile for a lens having a varying (increasing) thickness between the inner and outer surfaces as the lens extends from the optical lens axis (0 mm azimuth) to the periphery (i.e., the periphery of the lens is thicker than the center of the lens). Additionally, profile 304C is also an acoustic lens profile for a lens having a custom varying (oscillating) thickness between the inner and outer surfaces as the lens extends from the optical lens axis (0 mm azimuth) to the periphery (i.e., the thickness of the lens oscillates between a thick profile and a thin profile). The lens thickness varies according to one or more parameters. For example, the lens thickness may vary with the lens size (e.g., width / length / radius, etc.) such that the thickest portion of the lens is a multiple (e.g., 3 to 5 times) of the thinnest portion of the lens. Figure 3AIn profile 304B, as the lens extends from the central optical lens axis (0 mm azimuth) to the periphery, the inner lens surface curves away from the outer lens surface so that the magnification increases from 1 at the center to more than 2 at the periphery (12.5 mm azimuth). The rate at which the magnification increases may also depend on the lens material, lens shape, and other parameters, such as the distance of the lens from the probe transducer.

[0046] In the case of the lens with profile 304A, the echo enters the lens and reverberates in the attenuation graph 302 according to Case 1, while the lens with profile 304B and the lens with profile 304C have echoes reverberating in the attenuation graph 302 according to Case 2 and Case 3, respectively. It is apparent from the attenuation graph 302 that Case 2 and Case 3 have improved reverberation attenuation compared to Case 1. This improvement is due to the thickness variation between the inner and outer surfaces of the acoustic lens profiles 304B and 304C, which promotes phase modulation (different time delays) of different portions of the echo.

[0047] The acoustic lens can be made of a variety of solid materials. These materials can include hard materials that support acoustic transmission, such as plastics, including but not limited to polymethylpentene (PMP), which is a thermoplastic polyolefin. One type of PMP can be poly (4-methyl-1-pentene), known as Assuming the lens is composed of a uniform material, phase modulation is primarily due to the distance the acoustic signal propagates through the lens material. Specifically, the lens material provides an acoustic medium with a slower speed of sound than other media (such as air). Therefore, the portion of the acoustic wave that propagates through more lens material (i.e., propagates through a thicker portion of the lens) will be delayed in time relative to the portion of the acoustic wave that propagates through less lens material (i.e., propagates through a thinner portion of the lens).

[0048] As described above, in Case 1, phase modulation does not occur because portions of the acoustic wave propagate through the same amount of lens material regardless of the point of incidence on the lens (i.e., the portion of the wave incident on the center of the lens propagates through the same amount of lens material as the portion of the wave incident on the periphery of the lens). However, in Cases 2 and 3, phase modulation does occur because portions of the acoustic wave propagate through different amounts of lens material depending on the point of incidence on the lens. For example, in Case 2, the portion of the acoustic wave incident on the periphery of the lens will be phase delayed compared to the portion of the acoustic wave incident on the center of the lens.

[0049] The different thicknesses between the inner and outer surfaces in the acoustic lens profiles 304B and 304C are specifically selected based on the frequency of the acoustic signal, the structure of the probe, and other factors, so that the resulting phase modulation ensures that the reverberant waves are deconstructively combined, thereby attenuating any reverberation inside the probe. For Case 2, the outer lens profile (Equation 1) and the inner lens profile (Equation 2) describe the shapes of the inner and outer surfaces of the lens, the obtained time delay (Equation 3) describes the time delay (i.e., phase modulation) obtained for a given point on the lens surface, the coherent mirror reflection wave (Equation 4) describes the echo, and the coherent reflection wave attenuation (Equation 5) describes the attenuation of the echo due to the phase modulation. Referring to Table 1, these equations are as follows:

[0050] Equation 1

[0051] Equation 2

[0052] Equation 3

[0053] Equation 4

[0054] Equation 5

[0055]

[0056] Table 1

[0057] Here, the spherical inner contour generates a shell of different thickness in both azimuth and elevation directions. The induced phase modulation can be compensated by the beamformer to avoid degradation of the image quality, while the echo on the probe is greatly attenuated.

[0058] Although Figure 3A The data graph 300 shows signal attenuation for acoustic lens profiles of varying thicknesses, but reverberation attenuation may also be achieved with lenses of uniform thickness by adding texture to one or more lens surfaces. Figure 3BData graph 320 showing reverberation attenuation for uniform acoustic lens profiles. Specifically, profile 322A shows an acoustic lens profile for a uniform thickness lens having smooth inner and outer surfaces, while profile 322B shows an acoustic lens profile for a uniform thickness lens having a textured inner surface. As shown in data graph 324, the reverberation attenuation performance of the uniform thickness lens having a textured inner surface is better than the reverberation attenuation performance of the uniform thickness lens having a smooth surface. This is due to the phase modulation of the echo as a result of the textured surface. Specifically, the textured surface produces different time delays for different portions of the acoustic wave, depending on the angle of the textured surface relative to the portion of the incident acoustic wave. The outer and inner lens profile with roughness (Equation 6) describes the shape of the inner and outer surfaces of the lens with increased roughness, the phase modulation obtained due to roughness (Equation 7) describes the time delay (i.e., phase modulation) obtained for a given point on the lens surface due to the roughness, the effective root mean square roughness (Equation 8) describes the roughness of the lens, and the attenuation of the transmitted and reflected waves (Equations 9 and 10) is the attenuation of the transmitted and reflected waves due to phase modulation. Referring to Table 2, these equations are as follows:

[0059] Equation 6z2(x,y)=d2+ζ(x,y)

[0060] Equation 7φ r (x, y) = -2ζ(x, y)k2

[0061] Equation 8

[0062] Equation 9

[0063] Equation 10

[0064]

[0065] Table 2

[0066] As described above, phase modulation can be achieved by varying the thickness of the acoustic lens, adding texture to the acoustic lens surface, or a combination of both. Examples of textures include, but are not limited to, random textures / patterns achieved via random sandblasting techniques (e.g., electrical discharge machining to produce random electrical discharges) to randomly remove material from the acoustic lens surface while randomly leaving other lens materials intact. Of course, textures / patterns can be achieved by randomly depositing additional material on the lens surface, rather than removing material. Textures can achieve a desired roughness (e.g., 33-45) on a roughness scale (such as the known VDI3400 scale). The shape of the resulting textured surface can be sharp and / or rounded valleys / peaks in the lens surface. Figure 4A , Figure 4B and Figure 4C(described below) show various configurations of acoustic lenses with different thicknesses and textures. Note that while Figure 4A , Figure 4B and Figure 4C Lenses with rounded (ie, curved) and flat profiles are shown in , but other lens profiles are possible as long as at least one lens has a variation in thickness and the surface is textured to introduce phase modulation of the echo as it enters the probe.

[0067] Figure 4A A front view 400 of various acoustic lens profiles for a 2D probe (i.e., a probe with a 2D transducer array) is shown. Profiles 402A-402D show views of acoustic profiles of a circular acoustic lens, while profiles 404A-404D show views of profiles of a flat acoustic lens. Specifically, profiles 402A and 404A are lens profiles having a lens thickness that increases symmetrically from the center of the lens to the periphery of the lens, profiles 402B and 404B are lens profiles having a lens thickness that increases asymmetrically from one side of the lens to the opposite side of the lens to form a wedge, profiles 402C and 404C are lens profiles having a lens thickness that oscillates over the length of the lens, and profiles 402D and 404D are lens profiles having a uniform lens thickness and a textured internal lens surface.

[0068] Figure 4B Shows Figure 4A 420. Specifically, profiles 422A-422D show Figure 4A , while profiles 424A-424D show Figure 4A . Specifically, profiles 422A and 424A are lens profiles having a lens thickness that increases symmetrically from the center of the lens to the periphery of the lens, profiles 422B and 424B are lens profiles having a lens thickness that increases asymmetrically from one side of the lens to the opposite side of the lens, profiles 422C and 424C are lens profiles having a lens thickness that oscillates over the length of the lens, and profiles 422D and 424D are lens profiles having a uniform lens thickness and a textured interior lens surface.

[0069] Figure 4A and Figure 4B The lens profiles in are for 2D probes. However, the lens profiles described in this article are also applicable to 1D probes. For example, Figure 4CA front view 440 of various acoustic lens profiles for a ID probe is shown. Profile 442A is a lens profile having a circular lens with a thickness that increases symmetrically from the center of the lens to the periphery of the lens. Profile 442B is a lens profile having a flat lens with a thickness that increases symmetrically from the center of the lens to the periphery. Profile 442C is a lens profile having a flat lens with a thickness that increases symmetrically from the center of the lens to the periphery and includes a textured interior lens surface. Profile 442D is a lens profile having a circular lens with a thickness that increases symmetrically from the center of the lens to the periphery and includes a textured interior lens surface.

[0070] Note that a variety of lens profiles are possible by varying the thickness of the lens relative to the center and periphery of the lens, adding texture to one or more surfaces of the lens, or a combination of these two techniques. When adding texture to a lens surface, it may be beneficial to add the texture to the inner surface of the lens, especially in ultrasound probes where the outer texture may be uncomfortable for the patient. It should also be noted that it may be beneficial to have the texture have a non-periodic pattern to avoid interfering with the main signal within the operating range of the ultrasound probe. In other words, it may be beneficial to apply the texture in a pseudo-random manner to produce a white frequency response that adds phase modulation without adversely interfering with the acoustic signal. If the texture is applied in a periodic manner, care should be taken to ensure that the frequency response of the texture does not adversely interfere with the main frequency of the acoustic signal. For example, the period of the texture pattern may be set at a frequency above or below the operating frequency band of the acoustic signal used by the probe.

[0071] The acoustic lens described above can be manufactured using various techniques including molding, layered lamination, 3D printing, etc. In one example, Figure 5 A flow chart 500 is shown for manufacturing an acoustic lens and an ultrasound probe using a molding technique. In step 502, a lens material may be injected into a mold that is sized to produce lenses having at least one of varying lens thicknesses and internal lens surface textures. Optionally, rather than molding a lens having a texture in a single step, a lens having a smooth surface may be molded, and then texture may be added in step 504 by etching the smooth lens surface or laminating / overmolding an additional lens layer that includes a texture. Once the lens is molded, it may be inserted and secured in a housing of an ultrasound probe in step 506. Regardless of the manufacturing technique selected, the resulting lens may have varying thicknesses, textured surfaces, or a combination of both, so as to introduce a predetermined phase modulation to an acoustic signal that causes a reverberant signal to deconstructively combine to attenuate any reverberation present in the probe.

[0072] The above embodiments teach changing the thickness of the acoustic lens, adding texture to the surface of the acoustic lens, or a combination thereof to achieve phase modulation of the received acoustic signal. Phase modulation can be achieved using other methods, including combining two different materials to create a temporary profile between the inner / outer surface of a uniform thickness lens. For example, Figure 6 A lens profile 600 of an acoustic lens 602 having an outer profile, an inner profile, and a temporary profile is shown. The temporary profile can be achieved by mating the upper portion of the lens (the portion between the outer profile and the temporary profile) with the lower portion of the lens (the portion between the inner profile and the temporary profile). In other words, the upper portion of the lens is manufactured (e.g., molded) to have a uniform outer surface and an oscillating temporary surface, while the lower portion of the lens is manufactured (e.g., molded) to have a uniform inner surface and an oscillating temporary surface that is complementary to the temporary surface of the upper portion of the lens. This can be achieved by molding the upper portion of the lens and then overmolding the lower portion of the lens onto the upper portion of the lens, or vice versa. Another solution is to mold the upper portion and the lower portion separately and then laminate them together.

[0073] Note that the temporary lens profile can also be achieved by combining more than two layers of material (e.g., combining an upper layer, a temporary layer, and a lower layer of material). It should also be noted that this temporary profile technique can also be used in combination with the technique of varying the lens thickness and providing texture in the internal lens surface, as shown in 604. In either case, the resulting lens will produce the desired phase modulation of the sound waves for attenuating reverberation.

[0074] The acoustic lens having the above temporary profile can be manufactured using various techniques including molding, layered lamination, 3D printing, etc. In one example, Figure 7 A flow chart 700 for manufacturing an acoustic lens with a temporary profile for an ultrasound probe is shown. In step 702, a lens material is injected into a mold to produce a first lens layer (e.g., an upper layer). In step 704, the first lens layer is inserted into a mold, where a second lens layer (e.g., a temporary layer) is injected into the mold. In step 706, the combined first / second lens layer is inserted into a mold, where a third layer (e.g., an inner layer) is injected into the mold. Note that in steps 704 and 706, the molded lens layers can be removed from their existing molds and placed into new molds for each additional molding step, or the molded layers can stay in their existing molds, which are repositioned to new injection locations for each additional molding step. Note that when the upper and inner layers are made of different materials and have different corresponding temporary complementary profiles, the step of producing the temporary layer can be omitted. In either case, in step 708, the molded lens is inserted and secured in the ultrasound probe.

[0075] As described above, the different thicknesses and textured surfaces of the lens introduce time delays (i.e., phase modulation) to different parts of the sound wave, causing the reverberation waves within the probe to combine deconstructively. Figure 8 An example of a 2D transducer array 800 mounted below a lens (not shown) that introduces different time delays to the echoes is shown. Specifically, an inner ring of transducer elements receives echoes with a time delay T1, while an outer ring of transducer elements receives echoes with a greater time delay T2. These time delays can be achieved by having a lens having a first thickness near the center of the lens where the inner transducer elements are located and a second, greater thickness near the periphery of the lens where the outer transducer elements are located.

[0076] Although this configuration provides improved reverberation attenuation, the phase modulation also modifies the information in the received echoes, thereby distorting the constructed ultrasound image. In other words, an artificial delay is added to the waves, thereby misaligning portions of the waves when received. Therefore, before constructing the ultrasound image, the software executed by the processor of the computer 102 also compensates for the phase modulation to realign portions of the echoes.

[0077] Specifically, the profile of the lens may be known by the computer 102. Therefore, the additional time delay introduced by the lens profile is also known. In other words, the computer 102 knows that the signal received from the inner ring of transducer elements is delayed by time T1, while the signal received from the outer ring of transducer elements is delayed by a larger time T2. In order to compensate for phase modulation, the time difference (ΔT=T2-T1) is calculated to align the signals in time. For example, the computer 102 may add the delay ΔT to the signal received from the inner ring of transducer elements, thereby synchronizing all transducer signals. This process is called beamforming, in which the known relative differences in time delays due to the lens profile and / or lens surface texture are eliminated before image construction. In one example, as described above, these time delays may be known by the computer 102 based on the identity of the lens used in the probe. In another example, when the delays are unknown, the computer 102 may learn these delays over time using machine learning techniques or based on feedback from a technician. For example, the probe can aim at a target at a constant density and distance to the probe. If a uniform lens is used, all received transducer signals should be synchronized. However, since phase modulation is introduced in the lens, the relative phase shift between these signals can be measured to determine the phase modulation behavior of the lens. This learned phase modulation behavior can then be used to align the transducer signals during operation as described above.

[0078] Although the foregoing relates to the exemplary embodiments described herein, other and further exemplary embodiments may be envisioned without departing from the basic scope of the invention. For example, aspects of the present disclosure may be implemented in hardware or software or a combination of hardware and software. An exemplary embodiment described herein may be implemented as a program product for use with a computer system. The program of the program product defines the functions of the exemplary embodiments (including the methods described herein) and may be contained on various computer-readable storage media. Exemplary computer-readable storage media include, but are not limited to: (i) non-writable storage media (e.g., read-only memory (ROM) devices within a computer, such as CD-ROM disks that can be read by a CD-ROM drive, flash memory, ROM chips, or any type of solid-state non-volatile memory), on which information is permanently stored; and (ii) writable storage media (e.g., floppy disks within a floppy disk drive or hard drive or any type of solid-state random access memory), on which variable information is stored. Such computer-readable storage media are exemplary embodiments of the present disclosure when carrying computer-readable instructions that direct the functions of the disclosed exemplary embodiments.

[0079] It should be understood by those skilled in the art that the foregoing examples are illustrative and not restrictive. After reading the specification and studying the drawings, all permutations, enhancements, equivalents and improvements made to the present disclosure are obvious to those skilled in the art and are included in the true spirit and scope of the present disclosure. Therefore, the appended claims are intended to include all such modifications, permutations and equivalents that fall within the true spirit and scope of these teachings.

Claims

1. An ultrasound probe lens, comprising: a lens body comprising a solid material extending outwardly from an optical lens axis to a periphery; an inner surface of the lens body; and the outer surface of the lens body; The thickness of the lens body measured from the inner surface to the outer surface varies from the optical lens axis to the periphery, so that the lens body is configured with an inner optical profile and an outer optical profile to phase modulate ultrasonic waves incident on the lens body, thereby reducing reverberation. 2 . The ultrasound probe lens according to claim 1 , wherein the outer surface of the lens body includes a curved shape or a flat shape that changes the thickness of the lens body. 3 . The ultrasound probe lens according to claim 1 , wherein the inner surface of the lens body includes a curved shape or a wedge shape that changes the thickness of the lens body.

4. The ultrasound probe lens of claim 1, wherein the inner surface of the lens body comprises a customized shape that alternates between increasing and decreasing the thickness of the lens body. 5 . The ultrasound probe lens of claim 1 , wherein the thickness of the lens body increases from the optical lens axis to the periphery of the lens body. 6 . The ultrasound probe lens of claim 1 , wherein the thickness of the lens body decreases from the optical lens axis to the periphery of the lens body.

7. The ultrasound probe lens of claim 1, wherein the lens body includes a dimension from the optical lens axis to the periphery to reduce reverberation of the ultrasound wave in a field of view of a 1-dimensional (1D) ultrasound transducer.

8. The ultrasound probe lens of claim 1, wherein the lens body comprises a dimension from the optical lens axis to the periphery to reduce the reverberation of the ultrasound wave in a field of view of a 2-dimensional (2D) ultrasound transducer. 9 . The ultrasound probe lens of claim 1 , wherein the inner surface of the lens body comprises a texture configured to reduce the reverberation of the ultrasound wave.

10. The ultrasound probe lens of claim 1, wherein the solid material between the inner surface of the lens body and the outer surface of the lens body is configured to generate an internal optical profile to reduce the reverberation of the ultrasound wave.

11. An ultrasound probe, comprising: The ultrasound probe lens according to any one of claims 1 to 10; and A transducer is configured to transmit ultrasonic waves through the lens body, receive reflected ultrasonic waves through the lens body, and convert the received reflected ultrasonic waves into electrical signals for further processing.

12. The ultrasound probe of claim 11, wherein the further processing comprises processing the electrical signal to compensate for the phase modulation of the received reflected ultrasound waves caused by the lens.

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