Flexible ultrasonic transducer capable of detecting skin electrical impedance, driving device, and control method

Abstract

Disclosed in the present invention are a flexible ultrasonic transducer capable of detecting skin electrical impedance, a driving device, and a control method. The ultrasonic transducer comprises a coupling layer, an electrode layer, an array element layer, and a backing layer. The coupling layer is composed of a non-conductive flexible material and a conductive flexible material. The electrode layer is located below the coupling layer, and a second metal layer for connecting the conductive flexible material and the driving device and a fourth metal layer for grounding are provided in the electrode layer. The array element layer is attached to the electrode layer, and the array element comprises N transducer array elements, array element drive lines, and a flexible material, the flexible material being configured to fill the space between the transducer array elements. The backing layer is located below the array element layer. According to the flexible transducer of the present invention, by combining the driving device and the control method, skin electrical impedance can be detected, and the degree of coupling of the transducer can be detected on the basis of a skin electrical impedance value, thereby implementing real-time evaluation and feedback control of an ultrasonic wave emitting effect during emission.

Description

Flexible ultrasonic transducer capable of detecting skin electrical impedance, driving device and control method Technical Field

[0001] The invention relates to a flexible ultrasonic transducer capable of detecting skin electrical impedance, a driving device and a control method, and belongs to the technical field of flexible ultrasound. Background Art

[0002] Currently, ultrasound devices used in dermatology, such as ultrasound physiotherapy devices, ultrasound therapeutic devices, and ultrasound drug delivery devices, typically use piezoelectric ceramics as the core component of their ultrasonic transducers (ultrasound probes). These ultrasonic transducers typically consist of piezoelectric ceramics, electrode connections, and a housing structure, and some may also include temperature and humidity detection circuits. While these ultrasonic probes excel at generating ultrasound waves and can monitor the transducer's own operating conditions, they suffer from a limitation: they cannot promptly detect changes in tissue after ultrasound irradiation, and thus cannot provide feedback control over the ultrasound emission energy.

[0003] Moreover, these ultrasonic transducers usually have a rigid surface, so when applied to uneven skin, it is difficult to achieve good coupling with the skin. Therefore, in actual use, it is necessary to apply a coupling agent between the transducer surface and the skin surface, which causes many inconveniences during use.

[0004] Summary of the Invention

[0005] The present invention aims to provide a flexible ultrasonic transducer, drive device, and control method capable of detecting skin electrical impedance. By detecting skin electrical impedance during ultrasonic transmission, changes in tissue after ultrasonic irradiation can be promptly detected, and feedback control of ultrasonic transmission can be performed based on the detection results. Furthermore, the transducer is designed as a flexible material that can conform well to various shapes, effectively solving the coupling problem between the transducer and the skin without the need for a coupling agent.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A flexible ultrasonic transducer capable of detecting skin electrical impedance, comprising a coupling layer, an electrode layer, an array element layer, and a backing layer, wherein:

[0008] The coupling layer is composed of a non-conductive flexible material and a conductive flexible material;

[0009] The electrode layer is located below the coupling layer, and is provided with a second metal layer for connecting the conductive flexible material and the driving device and a fourth metal layer for grounding;

[0010] The array element layer is laminated to the electrode layer, and the array element layer comprises N transducer elements, element drive lines, and flexible material, wherein the flexible material is filled between the transducer elements;

[0011] The backing layer is located below the array element layer.

[0012] Furthermore, the thickness of the coupling layer is an odd multiple of one quarter of the ultrasonic wavelength.

[0013] Furthermore, the non-conductive flexible material is provided with an opening, and the opening is filled with the conductive flexible material.

[0014] Furthermore, the DC impedance and AC impedance of the non-conductive flexible material are greater than the measured skin impedance value; and the DC impedance and AC impedance of the conductive flexible material are less than the measured skin impedance value.

[0015] Furthermore, a cotton wool groove is provided on the coupling layer, and the cotton wool groove is used for placing the medicine-guiding cotton wool.

[0016] Furthermore, the electrode layer includes a first insulating layer, a second metal layer, a third insulating layer, a fourth metal layer, and a fifth insulating layer stacked in sequence.

[0017] Furthermore, the second metal layer is provided with an epithelial impedance detection electrode array, and the epithelial impedance detection electrode array includes N metal wires, and each metal wire is provided with a first metal electrode and a second metal electrode at both ends.

[0018] Furthermore, the metal wire adopts a serpentine structure that bends back and forth.

[0019] Furthermore, the first metal electrode is electrically connected to the conductive flexible material, and the second metal wire is electrically connected to the driving device.

[0020] Furthermore, an opening is provided in the first insulating layer above the first metal electrode, the opening is filled with a conductive flexible material, and the first metal electrode is electrically connected to the conductive flexible material.

[0021] Furthermore, the fourth metal layer L24 is electrically connected to the ground.

[0022] Furthermore, the array element layer includes N transducer elements, array element driving lines, and flexible material. The flexible material is filled between the transducer elements. The array element driving lines are arranged under the transducer elements and the flexible material, and are electrically connected to the transducer elements.

[0023] Furthermore, the distance D between the transducer array elements is min The minimum value of is calculated as follows:

[0024] Where h is the thickness of the transducer element, and β is the skin angle to which the ultrasound transducer needs to conform.

[0025] Furthermore, the top electrode of the transducer array element extends through the side surface of the array element to the bottom surface of the array element and is connected to the array element driving line, and the bottom electrode of the transducer array element is connected to the array element driving line.

[0026] Furthermore, the transducer array element is a planar array element or a curved array element, wherein the convex side of the curved array element faces upward, and the thickness of the non-conductive flexible material above the curved array element is greater than D L03 , D L03 The calculation formula is as follows:

[0027] Wherein, α is the radiation angle of the curved array element, r is the curvature radius of the curved array element, d is the width of the curved array element, h is the thickness of the curved array element, and D is the actual spacing between array elements.

[0028] A driving device for a flexible ultrasonic transducer, the driving device comprising a control unit, an impedance detection unit, and an array element driving unit. The control unit is electrically connected to the impedance detection unit and the array element driving unit. The array element driving unit is electrically connected to the transducer array elements and applies electrical driving signals to the transducer array elements respectively, thereby achieving ultrasonic emission.

[0029] Furthermore, the impedance detection unit includes N-channel impedance detection circuits, which are electrically connected to the metal wires of the epidermal impedance detection electrode array, and a detection resistor R is connected to the signal return end of the metal wire; the impedance detection unit sequentially controls each impedance detection circuit to apply an electrical excitation signal u0 to the metal wire, and simultaneously detects the return electrical signal u of each channel after passing through the skin tissue. n , where n is the channel number.

[0030] Furthermore, the electrical excitation signal u0 is an AC signal, and the control unit extracts one or more periodic signals u0′ after the electrical excitation signal u0 passes through zero for the first time, and extracts the return electrical signal u n One or more periodic signals u after the first zero crossing n ', the periodic signals u0' and u n ’ has the same number of periods.

[0031] Furthermore, the control unit calculates the complete impedance Z of the entire signal chain of each channel according to the following formula: total,n :

[0032] Among them, u0′ is one or more periodic signals after the electric excitation signal u0 crosses zero for the first time, u n ′ is the return electrical signal u n One or more periodic signals after the first zero crossing, where R is the resistance value of the detection resistor;

[0033] The control unit calculates the electrical impedance Z of the skin tissue according to the following formula: n : Z n =Z total,n -2Z t,n -2Z m,n -2Z l,n -Z s,n

[0034] Among them, n is the channel number, Z t,n is the equivalent impedance of the detection electrode L21, Z m,n is the equivalent impedance of the conductive flexible material, Z l,n is the equivalent impedance of the metal conductor, Z s,n is the equivalent impedance of the signal link on the impedance detection unit.

[0035] Furthermore, the electrical excitation signal u0 is a DC signal, and the control unit calculates the complete impedance Z of the entire signal chain of each channel according to the following formula: total,n :

[0036] Wherein, u0 is the electrical excitation signal, u n is the return electrical signal, and R is the resistance value of the detection resistor;

[0037] The control unit calculates the electrical impedance Z of the skin tissue according to the following formula: n : Z n =Z total,n -2Z t,n -2Z m,n -2Z l,n -Z s,n

[0038] Among them, n is the channel number, Z t,n is the equivalent impedance of the detection electrode L21, Z m,n is the equivalent impedance of the conductive flexible material, Z l,n is the equivalent impedance of the metal conductor, Z s,n is the equivalent impedance of the signal link on the impedance detection unit.

[0039] A control method for a flexible ultrasonic transducer driving device comprises the following steps:

[0040] S01: Control the impedance detection unit to apply an electrical excitation signal u0 to each channel impedance detection electrode in turn, where the electrical excitation signal u0 is an AC signal or a DC signal. If the electrical excitation signal u0 is an AC signal, execute steps S02 and S03; if the electrical excitation signal u0 is a DC signal, execute steps S02 and S04;

[0041] S02: Control the impedance detection unit to detect the return electrical signal u of each channel impedance detection electrode after passing through the skin tissue n ;

[0042] S03: If the electrical excitation signal u0 is an AC signal, extract the three periodic signals u0′ after the electrical excitation signal u0 first crosses zero, and extract the return electrical signal u n Three cycles of signal u after the first zero crossing n '; At the same time, the complete impedance Z of the entire signal chain of each channel is calculated according to the following formula total,n :

[0043] Wherein, u0′ is one or more periodic signals after the electric excitation signal u0 passes through zero for the first time, u n ' is the return electrical signal u n One or more periodic signals after the first zero crossing, where R is the resistance value of the detection resistor;

[0044] S04: If the electrical excitation signal u0 is a DC signal, the control unit calculates the complete impedance Z of the entire signal chain of each channel according to the following formula total,n :

[0045] Wherein, u0 is the electrical excitation signal, u n is the return electrical signal, and R is the resistance value of the detection resistor;

[0046] S05: Calculate the electrical impedance Z of the skin tissue according to the following formula n : Z n =Z total,n -2Z t,n -2Z m,n -2Z l,n -Z s,n

[0047] Among them, n is the channel number, Z t,n is the equivalent impedance of the detection electrode L21, Z m,n is the equivalent impedance of the conductive flexible material, Z l,n is the equivalent impedance of the metal conductor, Z s,n is the equivalent impedance of the signal link on the impedance detection unit;

[0048] S06: For each value Z n Calculate its deviation Z sn ;

[0049] Where μ is the value of all Z n The average value of

[0050] S07: Z sn Compared with the pre-set deviation threshold, the channel exceeding the deviation threshold is recorded as an abnormal channel;

[0051] S08: applying an electrical signal to the non-abnormal channel through the array element driving unit, thereby achieving ultrasonic emission;

[0052] S09: While the ultrasonic wave is being emitted, the impedance detection unit is used to detect the N-channel picoelectric impedance value again in sequence, which is recorded as Z n ';

[0053] S10: Calculate the change in the epithelial impedance of each channel after ultrasonic irradiation, recorded as Δk n , the calculation formula is as follows:

[0054] S11: Comparison Δk n With the preset dose threshold, for Δk n The channel with a dose greater than the threshold stops emitting ultrasound, while other channels continue to emit ultrasound;

[0055] S12: Repeat S03 to S07 until all channels reach the dose threshold.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] (1) The coupling layer and the element gap of the flexible transducer in this application are filled with flexible materials, and the metal wire is designed with a spring wire or a serpentine wire, so it has flexible and extensible characteristics and has good conformability to uneven skin.

[0058] (2) The flexible transducer in this application is designed with electrodes that can be used to detect epithelial impedance. Combined with a drive device and a control method, epithelial impedance detection can be achieved. The degree of transducer fit can be detected based on the epithelial impedance value, and real-time evaluation and feedback control of the ultrasonic emission effect can be achieved during the emission process.

[0059] (3) The flexible transducer in this application can independently control the ultrasonic emission of each array element according to the epidermal impedance value of each channel. Compared with ultrasonic transducers with single array element and multi-array element unified control, it can better ensure the ultrasonic irradiation effect at different positions and effectively solve the problem of inconsistent ultrasonic irradiation effect at different positions due to differences in fit, skin tissue density, and tissue ultrasonic sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] FIG1 is a schematic diagram of an embodiment of a flexible transducer in which transducer elements are rectangularly distributed and a 2×4 array is provided;

[0061] FIG2 is a schematic diagram of the coupling layer L1 of the embodiment shown in FIG1 ;

[0062] FIG3 is a schematic diagram of another implementation of the coupling layer L1 of the embodiment shown in FIG1 ;

[0063] FIG4 is a schematic diagram of the electrode layer L2 of the embodiment shown in FIG1 ;

[0064] FIG5 is a side schematic diagram of the embodiment shown in FIG1 ;

[0065] FIG6 is a side view of an embodiment of a curved array element;

[0066] FIG7 is a schematic top view of the array element layer L3 of the embodiment shown in FIG1 ;

[0067] FIG8 is a schematic bottom view of the array element layer L3 of the embodiment shown in FIG1 , which is opposite to the viewing angle of FIG5 ;

[0068] FIG9 is a schematic diagram of calculating the minimum distance between array elements;

[0069] FIG10 is a schematic diagram showing the calculation of the thickness of the flexible material L12 in the curved array element embodiment;

[0070] FIG11 is a schematic diagram of array element electrodes;

[0071] Figure 12 is a schematic diagram of a driving device;

[0072] FIG13 is a schematic diagram of an impedance detection unit detecting epithelial impedance;

[0073] FIG14 is an embodiment of an impedance detection circuit.

[0074] The markings in the figure are: L1-coupling layer; L2-electrode layer; L3-array element layer; L4-backing layer; L11-conductive flexible material; L12-non-conductive flexible material; L13-cotton wool groove; L21-first insulating layer; L22-second metal layer; L23-third insulating layer; L24-fourth metal layer; L25-fifth insulating layer; L221 metal wire; L222-first metal electrode; L223-second metal electrode; L31-transducer array element; L32-array element driving line; L33-flexible material; L311-top electrode; L312-bottom electrode; L51-control unit; L52-impedance detection unit; L53-array element driving unit. DETAILED DESCRIPTION

[0075] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0076] As shown in FIG1 , the ultrasonic transducer of this embodiment includes a coupling layer L1 , an electrode layer L2 , an element layer L3 , and a backing layer L4 .

[0077] As shown in Figure 2 , the coupling layer L1 is composed of a non-conductive flexible material L12 and a conductive flexible material L11. As shown in Figure 5 , the conductive flexible material L11 fills the opening above the metal electrode L222. In this embodiment, the opening is a circular shape with a diameter of 0.6 mm, the same size as the metal electrode L222.

[0078] In order to better couple with the skin, the conductive flexible material L11 is flush with the height of the non-conductive flexible material L12.

[0079] Furthermore, the non-conductive flexible material L12 is silicone rubber. To meet impedance measurement requirements, the DC and AC impedances of the non-conductive flexible material L12 must be greater than the measured epidermal impedance. In practical implementations, this impedance is recommended to be at least 10 times greater. In this embodiment, the measured epidermal impedance is 50-500 kΩ, and the impedance of the non-conductive flexible material should be greater than 5 MΩ. Therefore, silicone rubber is selected as the non-conductive flexible material in this embodiment.

[0080] Furthermore, the conductive flexible material L11 is a conductive hydrogel filled with conductive fibers. In actual implementation, the DC impedance and AC impedance of the conductive flexible material L11 need to be smaller than the measured skin impedance value, and the smaller the better. In this embodiment, the conductive hydrogel filled with conductive fibers is selected, and its DC impedance and AC impedance are about 1 kΩ, which is the minimum measured skin impedance. It is a more ideal choice.

[0081] Furthermore, the thickness of the coupling layer L1 is calculated according to the operating frequency of the transducer array element:

[0082] In this embodiment, according to the operating frequency f of the transducer array element = 1 MHz, the ultrasonic wavelength λ is calculated to be 1.5 mm, and the thickness of the coupling layer L1 is designed to be That is 1.875mm.

[0083] In another embodiment, as shown in FIG3 , the coupling layer L1 is further designed with a cotton wool groove L13 above the transducer array element L31 . The diameter of the cotton wool groove L13 is the size of the transducer array element, i.e. 8 mm, and is used for placing drug-introducing cotton wool.

[0084] Furthermore, as shown in Figures 1 and 4 , the electrode layer L2 is bonded to the coupling layer L1. Simultaneously, as shown in Figure 5 , the electrode layer L2 is positioned outside the ultrasonic radiation range of the transducer element L31. After assembly of the flexible ultrasonic transducer, the upper surface of the transducer element L31 is flush with or lower than the upper surface of the electrode layer L2, effectively preventing interference from ultrasonic radiation on the electrode layer L2.

[0085] Furthermore, the electrode layer L2 includes N epielectrical impedance detection electrodes. In order to achieve a flexible design of the entire transducer, the N epielectrical impedance detection electrodes are designed in the form of independent spring wires or serpentine wires.

[0086] Furthermore, as shown in FIG5 , each epithelial impedance detection electrode includes a first insulating layer L21 , a second metal layer L22 , a third insulating layer L23 , a fourth metal layer L24 , and a fifth insulating layer L25 , which are stacked in sequence.

[0087] The second metal layer L22 includes a first metal electrode L222, a metal wire L221, and a second metal electrode L223. The first metal electrode L222, the metal wire L221, and the second metal electrode L223 are electrically connected to each other, and the second metal electrode L223 is electrically connected to the driving device.

[0088] Furthermore, as shown in FIG5 , the first insulating layer L21 has a hole above the metal electrode L222 , and the hole is filled with the conductive flexible material L11 , thereby electrically connecting the first metal electrode L222 to the conductive flexible material L11 .

[0089] Furthermore, considering the spacing limitation of the transducer array element L31, as well as the processability of the metal electrode L222 and the metal wire L221 and the requirement to avoid the sound field radiated by the ultrasonic transducer array element L31, the first metal electrode L222 is designed as a circular electrode with a diameter of 0.6 mm, and the metal wire L221 is designed as a serpentine line with a width of 1.0 mm. Furthermore, the first metal electrode L222 is distributed around the transducer array element L31, thereby avoiding the sound field radiation range of the transducer array element L31. In order to better perform epithelial impedance measurement, it is recommended that the distance between each pair of electrodes be as far as possible in actual implementation. If the distance is too close, the measured epithelial impedance value may be too small, the error is large and it is easily affected by noise.

[0090] Furthermore, the fourth metal layer L24 is connected to the ground, thereby controlling the impedance of the metal wire L221 and isolating the transducer array element driving line L32 from interference.

[0091] In this embodiment, the second metal layer L22 and the fourth metal layer L24 are made of copper.

[0092] In order to ensure that the electrode layer L2 does not break during the stretching process, the third insulating layer L23 is made of a flexible material with a certain degree of flexibility. In this embodiment, the material selected is polyimide (PI).

[0093] In this embodiment, the coating insulating material of the first insulating layer L21 and the fifth insulating layer L25 is green oil.

[0094] Furthermore, as shown in Figure 7 and in conjunction with Figure 1 , the array element layer L3 is laminated to the electrode layer L2. In this embodiment, the array element layer includes 8 transducer elements L31 in a 2×4 pattern, as well as element drive lines L32 and flexible material L33, with the flexible material L33 filling the spaces between the transducer elements L31.

[0095] As shown in FIG8 and FIG11 , the top electrode L311 of the transducer element L31 extends from the side surface of the element to the bottom surface of the element and is connected to the element driving line L32. The bottom electrode L312 of the transducer element is connected to the element driving line L32.

[0096] As shown in Figures 5 and 7 , in this embodiment, the transducer array elements L31 are arranged in a rectangular 2×4 array. The transducer array elements L31 are planar elements with a diameter d of 8 mm, a thickness h of 1.63 mm, and an operating frequency f of 1 MHz. It should be noted that in actual applications, the transducer array element array can be arranged in a rectangular, circular, elliptical, or other arbitrary form, and the number of transducer array elements L31 can be arbitrary.

[0097] As further shown in FIG9 , in this embodiment, the skin angle β that the ultrasonic transducer needs to conform to is 110°, and the spacing D between the transducer elements L31 is calculated according to the following formula: min The minimum value is 1.87mm.

[0098] Where h is the thickness of the transducer element, and β is the skin angle to which the ultrasound transducer needs to conform.

[0099] Further combined with FIG. 4 , considering the machinability of the metal electrode L222 and the metal wire L221 and the requirement of avoiding the sound field radiation of the ultrasonic transducer array element L31 , the spacing between the transducer array elements L31 is actually designed to be 3 mm.

[0100] In this embodiment, each transducer array element can be controlled individually.

[0101] In this embodiment, the transducer array element is a planar element. Because the effective sound field of a planar element is approximately collimated, the maximum range of the effective sound field in the axial perpendicular plane is the area of ​​the planar element. When the ultrasonic transducer is flat, the effective sound field of the ultrasonic transducer has gaps. Skin or tissue in the gaps will not receive effective ultrasound irradiation. Therefore, this solution is suitable for scenarios with large skin surface curvature.

[0102] In another embodiment, as shown in FIG6 and FIG10, the transducer array element can be changed to a curved array element, with a diameter d of 8 mm, a thickness h of 1.63 mm, an opening angle α of 25°, and a curvature radius r of 8 mm. The convex side of the curved array element is upward. The thickness of the flexible material L12 above the curved array element is greater than D L03 When the ultrasonic transducer is in a flat shape, the effective sound field of the ultrasonic transducer has no gaps, which can ensure that all skin or tissues are effectively irradiated with ultrasound. Therefore, this solution is suitable for scenes with a relatively flat skin surface.

[0103] Furthermore, D L03 Calculated as 2.17 mm according to the following formula.

[0104] Wherein, α is the opening angle of the curved array element, r is the curvature radius of the curved array element, d is the width of the curved array element, h is the thickness of the curved array element, and D is the actual spacing between array elements.

[0105] As shown in Figure 12, in this embodiment, the driving device includes a control unit L51, an impedance detection unit L52, and an array element driving unit L53. The control unit includes a storage medium storing an executable program for executing the control method. The control unit L51 is electrically connected to the impedance detection unit L52 and the array element driving unit L53 and executes the control method. The array element driving unit L53 is electrically connected to the transducer array element L31 and applies electrical drive signals to each transducer array element L31, thereby achieving ultrasonic emission.

[0106] Furthermore, the impedance detection unit L52 includes an N-channel impedance detection circuit. The N-channel impedance detection circuit is electrically connected to the metal wire L221 of the epithelial impedance detection electrode array. A detection resistor R is connected to the signal return end of the metal wire L221, and the other end of the detection resistor R is grounded. In this embodiment, N = 8, and the value of the detection resistor R is 50 kΩ.

[0107] In this embodiment, the electrical excitation signal is an AC signal, which can detect the resistance, capacitance, and inductance of skin tissue. The AC signal can be set to different frequencies to detect the layered impedance of the skin tissue in the depth direction.

[0108] As shown in FIG13 , in this embodiment, the equivalent impedance Z of the detection electrode is t , the equivalent impedance Z of the metal wire L221 l , the equivalent impedance Z of the signal link on the impedance detection unit s The equivalent impedance Z of the conductive flexible material L11 is in milliohms and can be ignored. m 1KΩ.

[0109] In another embodiment, the electrical excitation signal is a DC signal. This embodiment can only detect the resistive value of the skin tissue, but cannot detect the inductive and capacitive values ​​of the skin tissue. However, the impedance detection unit is simple in design and low in cost, and is suitable for scenarios with low detection requirements.

[0110] As shown in FIG14 , in this embodiment, the control unit is an MCU, which can be a common control chip such as an ARM or FPGA. The impedance detection circuit shown includes a DDS chip AD9834, an op amp chip AD8091, and an ADC chip AD7476A. The MCU controls the DDS chip AD9834 to generate an electrical signal, which is amplified by the op amp AD8091 to generate the electrical excitation signal. Furthermore, the return electrical signal is amplified by the op amp AD8091 and transmitted to the ADC chip AD7476A. The MCU can detect the return electrical signal through the ADC chip AD7476A.

[0111] In this embodiment, the control method of the driving device includes the following steps:

[0112] S01: Control the impedance detection unit to apply an electrical excitation signal u0 to each channel impedance detection electrode in turn, where the electrical excitation signal u0 is an AC signal or a DC signal. If the electrical excitation signal u0 is an AC signal, execute steps S02 and S03; if the electrical excitation signal u0 is a DC signal, execute steps S02 and S04;

[0113] S02: Control the impedance detection unit to detect the return electrical signal u of each channel impedance detection electrode after passing through the skin tissue n ;

[0114] S03: If the electrical excitation signal u0 is an AC signal, extract the three periodic signals u0′ after the electrical excitation signal u0 first crosses zero, and extract the return electrical signal u n Three cycles of signal u after the first zero crossing n '; At the same time, the complete impedance Z of the entire signal chain of each channel is calculated according to the following formula total,n :

[0115] Wherein, u0′ is one or more periodic signals after the electric excitation signal u0 passes through zero for the first time, u n ' is the return electrical signal u n One or more periodic signals after the first zero crossing, where R is the resistance value of the detection resistor.

[0116] S04: If the electrical excitation signal u0 is a DC signal, the control unit calculates the complete impedance Z of the entire signal chain of each channel according to the following formula total,n :

[0117] Wherein, u0 is the electrical excitation signal, u n is the return electrical signal, and R is the resistance value of the detection resistor.

[0118] S05: Calculate the electrical impedance Z of the skin tissue according to the following formula n : Z n =Z total,n -2Z t,n -2Z m,n -2Z l,n -Z s,n

[0119] Among them, n is the channel number, Z t,n is the equivalent impedance of the detection electrode L21, Z m,n is the equivalent impedance of the conductive flexible material, Z l,nis the equivalent impedance of the metal conductor, Z s,n is the equivalent impedance of the signal link on the impedance detection unit;

[0120] S06: For each value Z n Calculate its deviation Z sn ;

[0121] Where μ is the value of all Z n The average value of

[0122] S07: Z sn Compared with the pre-set deviation threshold, the channel exceeding the deviation threshold is recorded as an abnormal channel;

[0123] S08: applying an electrical signal to the non-abnormal channel through the array element driving unit, thereby achieving ultrasonic emission;

[0124] S09: While the ultrasonic wave is being emitted, the impedance detection unit is used to detect the N-channel picoelectric impedance value again in sequence, which is recorded as Z n ';

[0125] S10: Calculate the change in the epithelial impedance of each channel after ultrasonic irradiation, recorded as Δk n , the calculation formula is as follows:

[0126] S11: Comparison Δk n With the preset dose threshold, for Δk n The channel with a dose greater than the threshold stops emitting ultrasound, while other channels continue to emit ultrasound;

[0127] S12: Repeat S03 to S07 until all channels reach the dose threshold.

[0128] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the scope of protection of the present invention in any form. All technical solutions obtained by equivalent substitution, etc., fall within the scope of protection of the present invention. Parts not covered by the present invention are the same as the existing technology or can be implemented using existing technology.

Claims

1. A flexible ultrasonic transducer capable of detecting skin impedance, characterized in that, The ultrasonic transducer includes a coupling layer, an electrode layer, an array element layer, and a backing layer, where: The coupling layer is composed of a non-conductive flexible material and a conductive flexible material; The electrode layer is located below the coupling layer. A second metal layer for connecting the conductive flexible material and the driving device and a fourth metal layer for grounding are provided in the electrode layer; The array element layer is attached to the electrode layer. The array element layer includes N transducer array elements, array element driving lines, and a flexible material, and the flexible material is filled between the transducer array elements; The backing layer is located below the array element layer.

2. The flexible ultrasonic transducer capable of detecting skin impedance according to claim 1, wherein, The thickness of the coupling layer is an odd multiple of one-fourth of the ultrasonic wavelength.

3. A flexible ultrasonic transducer capable of detecting skin impedance according to claim 1, characterized in that, Open holes are provided in the non-conductive flexible material, and the conductive flexible material is filled in the open holes.

4. The flexible ultrasonic transducer capable of detecting skin impedance according to claim 1, characterized in that, The DC impedance and AC impedance of the non-conductive flexible material are greater than the measured skin impedance value; the DC impedance and AC impedance of the conductive flexible material are less than the measured skin impedance value.

5. The flexible ultrasonic transducer capable of detecting skin impedance according to claim 2, characterized in that, A cotton wool groove is provided on the coupling layer, and the cotton wool groove is used to place the medicine-guiding cotton wool.

6. The flexible ultrasonic transducer capable of detecting skin impedance according to claim 1, wherein The electrode layer includes a first insulating layer, a second metal layer, a third insulating layer, a fourth metal layer, and a fifth insulating layer which are stacked in sequence.

7. The flexible ultrasonic transducer capable of detecting skin impedance according to claim 6, characterized in that, The second metal layer is provided with a skin impedance detection electrode array, and the skin impedance detection electrode array includes N metal wires, and a first metal electrode and a second metal electrode are respectively provided at both ends of each metal wire.

8. A flexible ultrasonic transducer capable of detecting skin impedance according to claim 7, characterized in that, The metal wire adopts a serpentine line structure with back-and-forth bends.

9. The flexible ultrasonic transducer capable of detecting skin impedance according to claim 7, wherein, The first metal electrode is electrically connected to the conductive flexible material, and the second metal electrode is electrically connected to the driving device.

10. A flexible ultrasonic transducer capable of detecting skin impedance according to claim 7, characterized in that, An open hole is provided in the first insulating layer above the first metal electrode, and the conductive flexible material is filled in the open hole, and the first metal electrode is electrically connected to the conductive flexible material.

11. A flexible ultrasonic transducer capable of detecting skin impedance according to claim 6, characterized in that, The fourth metal layer (L24) is electrically connected to the ground.

12. A flexible ultrasonic transducer capable of detecting skin impedance according to claim 1, wherein, The array element layer includes N transducer array elements, array element driving lines, and a flexible material, and the flexible material is filled between the transducer array elements. The array element driving lines are arranged below the transducer array elements and the flexible material, and are electrically connected to the transducer array elements.

13. A flexible ultrasonic transducer capable of detecting skin impedance according to claim 12, characterized in that, The spacing D between the transducer elements min has a minimum value calculated according to the following formula: Where h is the thickness of the transducer array element, and β is the skin angle to which the ultrasonic transducer needs to conform.

14. A flexible ultrasonic transducer capable of detecting skin impedance according to claim 12, characterized in that, The top electrode of the transducer array element extends to the bottom surface of the array element through the side surface of the array element and is connected to the array element driving line, and the bottom electrode of the transducer array element is connected to the array element driving line.

15. A flexible ultrasonic transducer capable of detecting skin impedance according to claim 12, characterized in that, The transducer element is a planar element or a curved element, wherein the convex side of the curved element faces upward, and the thickness of the non-conductive flexible material above the curved element is greater than D L03 , D L03 The calculation formula is as follows: Where α is the radiation angle of the curved surface type array element, r is the curvature radius of the curved surface type array element, d is the width of the curved surface type array element, h is the thickness of the curved surface type array element, and D is the actual distance between the array elements.

16. A driving device for the flexible ultrasonic transducer according to any one of claims 1 to 15, characterized in that, The driving device includes a control unit, an impedance detection unit, and an array element driving unit. The control unit is electrically connected to the impedance detection unit and the array element driving unit. The array element driving unit is electrically connected to the transducer array elements and respectively applies an electric driving signal to the transducer array elements to realize the emission of ultrasonic waves.

17. The drive device according to claim 16, characterized in that, The impedance detection unit includes N impedance detection circuits, the N impedance detection circuits are electrically connected to the metal wires of the skin impedance detection electrode array, and a detection resistor R is connected to the signal return end of the metal wire; the impedance detection unit sequentially controls each impedance detection circuit to apply an electrical excitation signal u0 to the metal wire, and simultaneously detects the returned electrical signal u of each channel after passing through the skin tissue n , where n is the channel number.

18. The drive device according to claim 17, characterized in that, The electrical excitation signal u0 is an alternating current signal, and the control unit extracts one or more periodic signals u0' after the first zero-crossing of the electrical excitation signal u0, and extracts the returned electrical signal u n one or more periodic signals u after the first zero-crossing n ′, and the periodic signals u0' and u n ′ have the same number of periods.

19. The drive device according to claim 18, characterized in that, The control unit calculates the complete impedance Z of the entire signal link for each channel according to the following formula total,n : Among them, u0′ is one or more cycle signals after the first zero-crossing of the electrical excitation signal u0, u n ′ is the returned electrical signal u n One or more cycle signals after the first zero-crossing, and R is the resistance value of the detection resistor; The control unit calculates the impedance Z of the skin tissue according to the following formula n :[[]]END]] Z n = Z total,n -2Z t,n -2Z m,n -2Z l,n -Z s,n where n is the channel number, Z t,n is the equivalent impedance of the detection electrode L21, Z m,n is the equivalent impedance of the conductive flexible material, Z l,n is the equivalent impedance of the metal wire, Z s,n is the equivalent impedance of the signal link on the impedance detection unit.

20. The drive device according to claim 17, characterized in that, The electrical excitation signal u0 is a DC signal, and the control unit calculates the complete impedance Z of the entire signal link for each channel according to the following formula total,n : Among them, u0 is the electrical excitation signal, and u n is the returned electrical signal, and R is the resistance value of the detection resistor; The control unit calculates the impedance Z of the skin tissue according to the following formula n :[[]]END]] Z n = Z total,n -2Z t,n -2Z m,n -2Z l,n -Z s,n where n is the channel number, Z t,n is the equivalent impedance of the detection electrode L21, Z m,n is the equivalent impedance of the conductive flexible material, Z l,n is the equivalent impedance of the metal wire, Z s,n is the equivalent impedance of the signal link on the impedance detection unit.

21. A control method for a drive device according to any one of claims 16 to 18, characterized in that Including the following steps: S01: The control impedance detection unit sequentially applies an electrical excitation signal u0 to each channel impedance detection electrode, where the electrical excitation signal u0 is an AC signal or a DC signal. If the electrical excitation signal u0 is an AC signal, steps S02 and S03 are executed; if the electrical excitation signal u0 is a DC signal, steps S02 and S04 are executed; S02: The control impedance detection unit detects the returned electrical signal u of each channel impedance detection electrode after passing through the skin tissue n ; S03: If the electrical excitation signal is the AC signal u0, extract three cycles after the first zero-crossing of the electrical excitation signal u0 Signal u0′, extract the returned electrical signal u n Three-cycle signal u after the first zero crossing n ′; At the same time, calculate the complete impedance Z of the entire signal link of each channel according to the following formula total,n : Among them, u0′ is one or more periodic signals after the first zero-crossing of the electric excitation signal u0, and u n ′ is one or more periodic signals after the first zero-crossing of the returned electric signal u n , and R is the resistance value of the detection resistor; S04: If the electrical excitation signal u0 is a DC signal, the control unit calculates the complete impedance Z of the entire signal link for each channel according to the following formula total,n : where u0 is the electrical excitation signal, and u n is the returned electrical signal, and R is the resistance value of the detection resistor; S05: Calculate the impedance Z of the skin tissue according to the following formula n : Z n = Z total,n -2Z t,n -2Z m,n -2Z l,n -Z s,n where n is the channel number, and Z t,n is the equivalent impedance of the detection electrode L21, Z m,n is the equivalent impedance of the conductive flexible material, Z l,n is the equivalent impedance of the metal wire, Z s,n is the equivalent impedance of the signal link on the impedance detection unit; S06: For each numerical value Z n Calculate its deviation Z sn ; where μ is the average value of all the values Z n ; S07: Compare Z sn with a preset deviation threshold, and mark the channels exceeding the deviation threshold as abnormal channels; S08: Apply an electrical signal to the non-abnormal channels through the array element driving unit, thereby realizing the emission of ultrasonic waves; S09: While the ultrasonic wave is being emitted, the impedance detection unit sequentially polls and detects the skin impedance values of the N channels again, denoted as Z n ′; S10: Calculate the change value of the skin impedance value of each channel after ultrasonic irradiation, denoted as Δk n , and the calculation formula is as follows: S11: Compare Δk n with a pre-set dose threshold. For Δk n channels greater than the dose threshold, stop emitting ultrasonic waves, and other channels continue to emit ultrasonic waves; S12: Repeat S03~S07 until all channels reach the dose threshold.

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