CN113019872A - Dual-frequency ultrasonic transducer for scanning imaging - Google Patents
Dual-frequency ultrasonic transducer for scanning imaging Download PDFInfo
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- CN113019872A CN113019872A CN202110448316.7A CN202110448316A CN113019872A CN 113019872 A CN113019872 A CN 113019872A CN 202110448316 A CN202110448316 A CN 202110448316A CN 113019872 A CN113019872 A CN 113019872A
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- 238000003384 imaging method Methods 0.000 title claims abstract description 18
- 239000000758 substrate Substances 0.000 claims abstract description 24
- 239000010410 layer Substances 0.000 claims description 30
- 239000002184 metal Substances 0.000 claims description 8
- 239000002346 layers by function Substances 0.000 claims description 4
- 230000009977 dual effect Effects 0.000 claims 1
- 238000002604 ultrasonography Methods 0.000 claims 1
- 238000013459 approach Methods 0.000 abstract description 6
- 238000013461 design Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000003491 array Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000002059 diagnostic imaging Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000009659 non-destructive testing Methods 0.000 description 1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
- B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
- B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
- B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
- B06B1/06—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/50—Piezoelectric or electrostrictive devices having a stacked or multilayer structure
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- Ultra Sonic Daignosis Equipment (AREA)
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Abstract
The invention discloses a double-frequency ultrasonic transducer for scanning imaging, which belongs to the technical field of piezoelectric micro-mechanics and solves the problem of resonance interference of piezoelectric micro-mechanical transducers in the prior art1λ/4, diameter d of small transducer2And λ/8, wherein λ is the wavelength at the resonant frequency of the transducer unit, the small transducers are distributed in a uniform array around the large transducers, the distance between the centers of two adjacent large transducers is λ/2, and the distance between the centers of two adjacent small transducers is λ/4. The invention provides a piezoelectric micro-mechanical transducer array for realizing two different resonant frequencies on one substrate, reduces the resonance interference between transducers, effectively improves the intensity of reflected signals, reduces the dead zone of an approach angle and improves the formationLike the resolution.
Description
Technical Field
The invention belongs to the technical field of piezoelectric micro-machinery, and discloses a dual-frequency ultrasonic transducer for scanning imaging.
Background
The ultrasonic transducer has higher transmitting intensity and receiving sensitivity, can be used for large-scale array application, such as a linear array, a surrounding array, a two-dimensional matrix array and the like, and has wide application in nondestructive testing and medical imaging systems. The piezoelectric micro-mechanical transducer is a transducer which can convert electric energy into sound energy by utilizing the inverse piezoelectric effect of a piezoelectric material, or convert the sound energy into the electric energy by utilizing the piezoelectric effect, and the ultrasonic scanning imaging function can be completed by processing a reflected signal through an external circuit and a signal processing algorithm according to the transmitting and receiving states of the transducer. In practical scenarios, transducer arrays are often used to increase the reflected signal strength, resulting in higher signal-to-noise ratio and image resolution.
The basic structure of a conventional piezoelectric micromachined transducer array is shown in fig. 1. The structural layers of a single transducer unit are shown in fig. 2. When the thickness of each structural layer is constant, the resonant frequency of the transducer is related only to the diameter d of the transducer. For transducer element centre distance dsIt has a large impact on the quality of the reflected signal from the transducer array. When d issWhen the size of the transducer array is small, the arrangement of the transducer array is relatively dense, the transducer array can obtain larger signal intensity, but the transducer units can generate serious mutual interference, so that a nonlinear effect is caused, and the imaging quality is reduced. When d issWhen great, the transducer array arranges sparsely relatively, and the interference is showing to be reduced between the transducer unit this moment, nevertheless because transducer unit centre of circle is great, causes the angle of approach blind area great, when the measured object is too close to the transducer promptly, positive transducer because ultrasonic wave propagation distance is short effectively to detect the signal excessively, adjacent transducer because the distance is far away can not receive sufficient signal, consequently causes the object formation of image of angle of approach blind area.
In addition, the transducer array has the problems of resonance interference among transducer units, and transducer array area waste caused by excessively large center distance of the transducer units. Therefore, the design of the piezoelectric micromechanical transducer array always needs to be balanced among many factors which are mutually restricted, such as reflected signal quality, imaging resolution, approach angle dead zone, resonance interference suppression and the like.
Disclosure of Invention
The invention aims to:
in order to solve the problem of resonance interference of a piezoelectric micro-mechanical transducer in the prior art, a dual-frequency ultrasonic transducer for scanning imaging is provided.
The technical scheme adopted by the invention is as follows:
a dual-frequency ultrasonic transducer for scanning imaging comprises a substrate, wherein a plurality of transducer units are mounted on the substrate, each transducer unit consists of a plurality of large transducers and a plurality of small transducers, and the diameter d of each large transducer1λ/4, diameter d of small transducer2And λ/8, wherein λ is the wavelength at the resonant frequency of the transducer unit, the small transducers are distributed in a uniform array around the large transducers, the distance between the centers of two adjacent large transducers is λ/2, and the distance between the centers of two adjacent small transducers is λ/4.
The resonant frequency of a piezoelectric micromachined transducer is primarily determined by the structural layer thickness and the transducer diameter, and at the design end of the transducer, the resonant frequency is determined only by the transducer diameter d, since the structural layer thickness is typically determined by the wafer parameters used for fabrication. Transducer unit center distance dsThe scan range of the transducer array is determined, which follows the following equation:
wherein d issIs the transducer element center distance, θsIs the scan angle and λ is the wavelength at the resonant frequency of the transducer element. From the formula, it is found that ideally the scan angle is maximized, i.e. 90 °, with the transducer cell centre to centre distance being half the wavelength, i.e. λ/2.
In the case of a material determination of the object to be measured, the sound velocity c of the acoustic wave in this material is determined. The relationship between the wavelength λ and the resonant frequency f of the transducer element follows the following equation: c ═ λ f;
therefore, when any value of the wavelength λ and the resonant frequency f is determined, the other value can be calculated. Thus, the transducer diameter d and the transducer unit centre distance d can be determinedsSet to a suitable value. The transducer unit at this time is named as a large transducer with a transducer diameter d1Resonant frequency of f1. From the foregoing, dsSince the transducer resonance frequency range for scanogram imaging is typically 1MHz to 5MHz, large transducer diameters d are designed1Is lambda/4.
Further, the transducer unit comprises a first metal layer, a functional layer, a second metal layer, a structural layer, a first basal layer and a second basal layer which are sequentially connected from top to bottom, and transducer cavities are arranged in the first basal layer and the second basal layer.
Furthermore, the large transducers are distributed in a uniform array shape, and the small transducers are arranged on the middle point of a connecting line of the circle centers of the two adjacent large transducers and the middle point of the diagonal line of the two large transducers.
Furthermore, the substrate is provided with 8 × 8 or 64 large transducers distributed in a uniform array, and 161 small transducers are arranged between the large transducers.
Further, the large transducers are distributed in a staggered array, and the relative position distances of two adjacent columns of large transducers are different by lambda/4.
In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:
1. the invention provides a piezoelectric micro-mechanical transducer array for realizing two different resonant frequencies on one substrate, the transducers of the two frequencies are not interfered with each other in performance and are complemented with each other in function, a large transducer works at the maximum scanning angle, the scanning range is ensured to the maximum extent, the resonance interference between the transducers is reduced, the small transducer effectively improves the intensity of reflected signals, reduces the dead zone of the approach angle and improves the imaging resolution.
2. The size and the position of all transducer units are strictly parameterized by formula calculation, so that the use effect of the transducer is ensured.
3. The piezoelectric micro mechanical transducer array is provided with the piezoelectric micro mechanical transducer arrays which are uniformly arranged and staggered, the array structure can be selected according to actual needs, the use is flexible, and the sound pressure distribution of all positions of a transmitting signal is more uniform.
Drawings
FIG. 1 is a prior art piezoelectric ultrasonic transducer construction;
FIG. 2 is a side cross-sectional view of a piezoelectric ultrasonic transducer of the present invention;
FIG. 3 is a schematic diagram of a uniform array-like distribution of large transducers of the present invention;
FIG. 4 is a view of the layout of the large transducers on the substrate of FIG. 3;
FIG. 5 is a schematic diagram of the sound pressure distribution of the large transducer in the distribution of FIG. 3;
FIG. 6 is a view of the present invention showing the structure of the large transducers in a staggered array on a substrate;
fig. 7 is a schematic diagram of the sound pressure magnitude distribution of the transducer elements in the distribution of fig. 6.
The labels in the figure are: 1-substrate, 2-large transducer, 3-small transducer, 4-sound pressure weak area, 101-first metal layer, 102-functional layer, 103-second metal layer, 104-structural layer, 105-first substrate layer and 106-second substrate layer.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
A dual-frequency ultrasonic transducer for scanning imaging comprises a substrate 1, wherein a plurality of transducer units are mounted on the substrate 1, each transducer unit is composed of a plurality of large transducers 2 and a plurality of small transducers 3, the diameter d1 of each large transducer 2 is lambda/4, the diameter d2 of each small transducer 3 is lambda/8, lambda is the wavelength of the transducer unit at the resonance frequency, the small transducers 3 are uniformly distributed around the large transducers 2 in an array shape, the distance between the centers of two adjacent large transducers 2 is lambda/2, and the distance between the centers of two adjacent small transducers 3 is lambda/4.
The transducer unit comprises a first metal layer 101, a functional layer 102, a second metal layer 103, a structural layer 104, a first substrate layer 105 and a second substrate layer 106 which are sequentially connected from top to bottom, and transducer cavities are arranged inside the first substrate layer 105 and the second substrate layer 106.
Example 1
As a preferred embodiment, as shown in fig. 4, the large transducers 2 are distributed in a uniform array, the small transducers 3 are mounted on the middle point of the connecting line of the circle centers of two adjacent large transducers 2 and the middle point of the diagonal of the two large transducers 2, 8 × 8 ═ 64 large transducers 2 are mounted on the substrate 1, and 161 small transducers 3 are mounted between the large transducers 2.
In this embodiment, the center distance ds between the large transducers 2 is large, and at this time, the interference between the large transducers 2 is significantly reduced, but the reflected signal intensity is insufficient, and the proximity angle dead zone is large. Since the center distance ds of the transducer unit is strictly designed according to ds ═ λ/2, which causes a serious waste of the use area of the whole transducer array, as shown in fig. 5, a large sound pressure weak area 4 exists, so that at the center point of the center distance of the unit of the large transducer 2, a small transducer 3 is designed, the transducer diameter d2 of which is the resonance frequency f 2. Where d2 is λ/8. Furthermore, on the diagonal of the large transducer 2, a small transducer 3 is also provided, as shown in fig. 3.
As shown in fig. 4. The transducer array is composed of 64 large transducers 2 with 8x8 and 161 small transducers 3 with 8x7+15x 7. The piezoelectric micro-mechanical transducer array works at the maximum scanning angle by the large transducer 2, the scanning range is ensured to the maximum extent, and meanwhile resonance interference among the transducers is reduced. And the small transducers 3 are arranged by fully utilizing the blank space of the array under the condition of not influencing the array of the large transducers 2, so that the intensity of the reflected signals is effectively improved, the dead zone of the approach angle is reduced, and the imaging resolution is improved. The embodiment effectively solves the problems of the prior piezoelectric micro-mechanical transducer array.
Example 2
In a preferred embodiment, as shown in fig. 6, the large transducers 2 are distributed in a staggered array, and the relative positions of two adjacent rows of the large transducers 2 are different by λ/4. The number of large transducers 2 in two adjacent columns is 8 and 7 respectively.
Since the large transducer 2 is decisive for the function of the device, the small transducer 3 is complementary and optimal. Aiming at the arrangement of the large transducers 2, the distribution of the whole sound pressure is not uniform enough, on the basis of the figure 6, on the basis of the figure 4, the staggered arrangement design is carried out, the positions of two adjacent rows of the large transducers 2 are staggered by lambda/4, and the staggered vacant positions are supplemented by the small transducers 3. Such a staggered design makes the sound pressure distribution more uniform throughout the layout of the large transducer 2, as shown in fig. 7.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (5)
1. A dual-frequency ultrasonic transducer for scanning imaging is characterized by comprising a substrate (1), wherein a plurality of transducer units are mounted on the substrate (1), each transducer unit consists of a plurality of large transducers (2) and a plurality of small transducers (3), the diameter d1 of each large transducer (2) is lambda/4, the diameter d2 of each small transducer (3) is lambda/8, lambda is the wavelength at the resonance frequency of each transducer unit, the small transducers (3) are uniformly distributed around the large transducers (2) in an array shape, the distance between the centers of two adjacent large transducers (2) is lambda/2, and the distance between the centers of two adjacent small transducers (3) is lambda/4.
2. The dual-frequency ultrasonic transducer for scanning imaging according to claim 1, wherein the transducer unit comprises a first metal layer (101), a functional layer (102), a second metal layer (103), a structural layer (104), a first substrate layer (105) and a second substrate layer (106) which are connected in sequence from top to bottom, and a transducer cavity is arranged inside the first substrate layer (105) and the second substrate layer (106).
3. The dual-frequency ultrasonic transducer for scanning imaging according to claim 1, wherein the large transducers (2) are distributed in a uniform array, and the small transducers (3) are arranged on the middle point of the connecting line of the circle centers of two adjacent large transducers (2) and the middle point of the diagonal of the two large transducers (2).
4. The dual frequency ultrasound transducer for scanning imaging according to claim 3, wherein 8x 8-64 large transducers (2) are mounted on the substrate (1) in a uniform array, and 161 small transducers (3) are mounted between the large transducers (2).
5. The dual-frequency ultrasonic transducer for scanning imaging according to claim 1, wherein the large transducers (2) are distributed in a staggered array, and the relative positions of two adjacent columns of large transducers (2) are different from each other by a distance of λ/4.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110448316.7A CN113019872A (en) | 2021-04-25 | 2021-04-25 | Dual-frequency ultrasonic transducer for scanning imaging |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110448316.7A CN113019872A (en) | 2021-04-25 | 2021-04-25 | Dual-frequency ultrasonic transducer for scanning imaging |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023284211A1 (en) * | 2021-07-15 | 2023-01-19 | 深圳市赛禾医疗技术有限公司 | Intracardiac two-dimensional ultrasound imaging catheter and system having same |
| WO2024041179A1 (en) * | 2022-08-25 | 2024-02-29 | 华为技术有限公司 | Transducer and imaging system |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109171816A (en) * | 2018-09-05 | 2019-01-11 | 中北大学 | It is a kind of for checking the ultrasonic CT system and its scan method of mammary gland |
| CN111001553A (en) * | 2019-12-18 | 2020-04-14 | 武汉大学 | Tunable ultrasonic sensor array |
| CN111250376A (en) * | 2020-01-15 | 2020-06-09 | 江苏英特神斯科技有限公司 | Multi-frequency self-focusing micro-mechanical ultrasonic transducer |
-
2021
- 2021-04-25 CN CN202110448316.7A patent/CN113019872A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109171816A (en) * | 2018-09-05 | 2019-01-11 | 中北大学 | It is a kind of for checking the ultrasonic CT system and its scan method of mammary gland |
| CN111001553A (en) * | 2019-12-18 | 2020-04-14 | 武汉大学 | Tunable ultrasonic sensor array |
| CN111250376A (en) * | 2020-01-15 | 2020-06-09 | 江苏英特神斯科技有限公司 | Multi-frequency self-focusing micro-mechanical ultrasonic transducer |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023284211A1 (en) * | 2021-07-15 | 2023-01-19 | 深圳市赛禾医疗技术有限公司 | Intracardiac two-dimensional ultrasound imaging catheter and system having same |
| WO2024041179A1 (en) * | 2022-08-25 | 2024-02-29 | 华为技术有限公司 | Transducer and imaging system |
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