TW202015262A - Ultrasonic sensor and method for making ultrasonic sensor - Google Patents

Abstract

The present disclosure provides an ultrasonic sensor including a substrate and an ultrasonic sensing layer supported by the substrate. The ultrasonic sensing layer includes a piezoelectric layer and at least an electrode layer located on the piezoelectric layer. The ultrasonic sensing layer can transmit and receive ultrasonic signals. The ultrasonic sensor of the present disclosure can transmit and receive the ultrasonic signals by the same ultrasonic sensing layer, thereby reducing the thickness of the ultrasonic sensor.

Description

Ultrasonic sensor and method of manufacturing ultrasonic sensor

The invention relates to an ultrasonic sensor and a method for manufacturing an ultrasonic sensor.

In contemporary society, people's own health awareness is generally improved. In addition to the high attention paid to work, rest, diet and exercise, regular physical examination is also essential. Ultrasound examination system uses ultra-high frequency sound waves to pass through the human body, and the reflection of sound waves by different tissues is different. After collecting these reflected waves, the precise calculation of the computer shows the structure of the tissues in the body for the doctor to judge whether it is normal or not. abnormal.

At present, ultrasonic sensors have been widely used in medical imaging equipment because of their advantages of small size, low price, and safety. However, the conventional ultrasonic sensors usually include a plurality of layered structures such as a protective layer, a signal receiving layer, a substrate, a signal transmitting layer, and a soft layer, which make the ultrasonic sensor thicker, which is not conducive to ultrasonic waves. Thinner and lighter sensors.

In view of this, the present invention provides an ultrasonic sensor with a small thickness.

An ultrasonic sensor includes: a substrate; an ultrasonic sensing layer, the substrate is used to support the ultrasonic sensing layer; the ultrasonic sensing layer includes a piezoelectric layer and at least one electrode layer stacked The ultrasonic sensing layer is used to send and receive ultrasonic signals.

The invention also provides a method for manufacturing an ultrasonic sensor.

A method for manufacturing an ultrasonic sensor, comprising: providing a substrate, the substrate is a thin film transistor array substrate, a sensing area and a peripheral area adjacent to the sensing area are defined on the substrate; on the substrate Forming a mask, the mask including an opaque region and a transparent region, the opaque region covering the peripheral region of the substrate, the transparent region covering the sensing region of the substrate; coating a piezoelectric polymer material In the sensing area, remove the mask to form a piezoelectric layer located in the sensing area; form an electrode layer covering the piezoelectric layer; the piezoelectric layer and the electrode layer serve as ultrasonic sensing Layer, the ultrasound sensing layer is used to send and receive ultrasound signals.

A method for manufacturing an ultrasonic sensor includes: providing a mother substrate, the mother substrate includes a plurality of substrates, the substrate is a thin film transistor array substrate, each of the substrates defines a sensing area and the A peripheral area adjacent to the sensing area; forming a mask on the mother substrate, the mask including an opaque area and a transparent area, the opaque area covering the peripheral area of each of the substrate, the The light-transmitting area covers the sensing area of each of the substrates; the piezoelectric polymer material is coated on each of the sensing areas, and the mask is removed to form a piezoelectric layer located in each of the sensing areas; The electrode layer of the piezoelectric layer, each of the piezoelectric layer and the corresponding electrode layer serves as an ultrasonic sensing layer, the ultrasonic sensing layer is used to send and receive ultrasonic signals; along the plurality of substrates The edge cuts the mother substrate to form a plurality of ultrasonic sensors.

Compared with the conventional technology, the ultrasonic sensor of the present invention realizes the transmission and reception of ultrasonic signals by the same ultrasonic sensing layer, without separately setting the signal transmitting layer and the signal receiving layer, which reduces the ultrasonic sensor thickness of.

This embodiment uses a wearable ultrasonic sensing device as an example for description. However, it is not limited to a wearable ultrasonic sensing device. In other embodiments, the ultrasonic sensing device of the present invention may be applicable to the present technology Scheme of other types of ultrasonic sensing devices. Specifically, a specific embodiment of the ultrasonic sensing device of the present invention will be described below by taking a wearable ultrasonic sensing device as an example.

Please refer to FIG. 1, which is a schematic perspective view of an ultrasonic sensing device 100 according to a first embodiment of the present invention. As shown in FIG. 1, in this embodiment, the ultrasonic sensing device 100 is a wearable ultrasonic sensing device. The ultrasonic sensing device 100 includes an ultrasonic sensor 10, which can be used to monitor physiological parameters such as blood flow, blood vessel elasticity, heart rate, and heart contractility of the test object. The technology can use the Doppler effect .

In this embodiment, the ultrasonic sensor 10 is a patch type, which can better closely adhere to the user's skin, so that the diagnosis of the ultrasonic sensor 10 is not affected by the air gap between it and the skin , Which enables more accurate diagnosis.

Please refer to FIG. 2, which is a schematic cross-sectional view taken along line II-II of FIG. In this embodiment, the ultrasonic sensor 10 includes a protective layer 11, a substrate 12, an ultrasonic sensing layer 13 and a flexible layer 14 which are sequentially stacked. The substrate 12 is used to support the ultrasonic sensing layer 13. Further, the substrate 12 and the ultrasonic sensing layer 13 are connected and fixed through the adhesive layer 15. When the ultrasonic sensor 10 is used, the soft layer 14 is used to fit the skin of the user. The protective layer 11 can protect the ultrasonic sensing layer 13.

As shown in FIG. 2, the ultrasonic sensing layer 13 includes a piezoelectric layer 131 and at least one electrode layer 132. The ultrasonic sensing layer 13 is used to transmit and receive ultrasonic signals. In this embodiment, the ultrasonic sensor 10 further includes a control unit (not shown) electrically connected to the ultrasonic sensing layer 13. The control unit controls the ultrasonic sensing layer 13 in a time-sharing manner to enable ultrasonic sensing The layer 13 realizes the functions of transmitting and receiving ultrasonic signals in a time-sharing manner, without separately setting a signal transmitting layer for transmitting ultrasonic signals and a signal receiving layer for receiving ultrasonic signals, which can reduce the thickness of the ultrasonic sensor 10.

As shown in FIG. 2, a thin film transistor (TFT) 121 arranged in a complex matrix may be formed on the surface of the substrate 12. The plural thin film transistors 121 form a thin film transistor array and an ultrasonic sensing layer 13. Sexual coupling. The thin film transistor array is used to receive the electrical signal from the ultrasonic sensing layer 13 and convert the received electrical signal into image or data information for the user to read. In this embodiment, the substrate 12 is a flexible material, such as silicone, plastic (such as polyimide (PI) or polyethylene terephthalate (PET)), etc., to facilitate the ultrasonic sensor 10 and use The fit. In other embodiments, the substrate 12 has a certain curvature, so that the ultrasonic sensor 10 can fit the detected position of the user (such as the arm). The material of the substrate 12 can be glass or sapphire, but not This is the limit.

When using the ultrasonic sensor 10, the user first puts the side of the ultrasonic sensor 10 with the soft layer 14 on the skin surface, for example, wears it on the wrist, and turns on the power of the ultrasonic sensor 10 Switch, at this time, the ultrasonic sensing layer 13 emits ultrasonic waves, and the ultrasonic waves are sent to the human body to enter the subcutaneous tissue and part of the ultrasonic waves are reflected from the subcutaneous tissue to the ultrasonic sensing layer 13, which is reflected by the change of the subcutaneous tissue state of the hand The intensity of the ultrasonic wave changes accordingly, so that an electrical signal corresponding to the blood flow of the user is coupled to the thin film transistor 121. The thin film transistor 121 converts the electrical signal into image information or data information and saves it in the memory or directly sends it to an external reading device.

In an embodiment, taking the ultrasonic sensor 10 detecting blood flow as an example, the ultrasonic sensor layer 13 exemplarily generates ultrasonic waves with a frequency of 2.5 MHz, and the ultrasonic waves penetrate into the blood vessel. The blood cells in the blood are reflected back to the ultrasonic sensor 10. At this time, since the ultrasonic wave and the blood cell have relative motion, the frequency of the ultrasonic wave returned to the ultrasonic wave sensing layer 13 changes according to the Doppler effect. For example, the amount of change in the frequency of the ultrasonic wave may be 0-4 kHz, that is, the frequency of the ultrasonic wave transmitted back to the ultrasonic wave sensing layer 13 may be 2.5 MHz±4 kHz. At this time, the amount of change in the frequency of the ultrasonic wave is defined as an audio signal. By analyzing the audio signal, the parameters of the blood flow can be analyzed.

The piezoelectric layer 131 may be a piezoelectric material such as polyvinylidene fluoride (PVDF), piezoelectric ceramic lead zirconate titanate (PZT), a copolymer of vinylidene fluoride and trifluoroethylene (PVDF-TrFE). In this embodiment, the piezoelectric layer is a copolymer of vinylidene fluoride and trifluoroethylene (PVDF-TrFE).

The electrode layer 132 may be selected from one of indium tin oxide, zinc oxide, poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid, carbon nanotubes, silver nanowires, and graphene, but not This is limited.

The soft layer 14 may be latex, for example. The ultrasonic sensor 10 can be closely adhered to the skin of the user through the soft layer 14 so that the diagnosis of the ultrasonic sensor 10 is not affected by the air gap between it and the skin, so that the diagnosis can be performed more accurately.

The protective layer 11 is also a flexible material, which ensures that the ultrasound sensor 10 as a whole is flexible and can be attached to the user's skin.

In this embodiment, the adhesive layer 15 may be an anisotropic conductive adhesive, and the charge generated by the piezoelectric layer 131 can be transferred to the thin film transistor 121 through the adhesive layer 15.

For convenience of description, the element symbols of the following embodiments follow the element symbols of the first embodiment, and the description of the same structure or function is not repeated here.

Please refer to FIG. 3, which is a schematic cross-sectional structural diagram of an ultrasonic sensor 10 according to a second embodiment of the present invention. The difference between the ultrasonic sensor 10 of this embodiment and the ultrasonic sensor 10 of the first embodiment is that: in this embodiment, the ultrasonic sensing layer 13 includes a plurality of independent sensing units 130, Each sensing unit 130 includes a piezoelectric layer 131 and an electrode layer 132 that are stacked. The complex sensing units 130 each transmit ultrasonic waves to form a beam forming mode. In this beamforming mode, for a sensing unit 130, the ultrasound transmitted by it is weighted and retransmitted with the ultrasound transmitted by the two adjacent sensing units 130 to form a narrow transmit beam, thereby enhancing The transmitted signal of the ultrasonic sensing layer 13 as a whole also correspondingly enhances the received signal strength of the ultrasonic sensing layer 13.

Please refer to FIGS. 4-8. FIG. 4 is a manufacturing flow chart of the ultrasonic sensor 10 according to the first embodiment of the present invention, and FIGS. 5-8 are the manufacturing steps of the ultrasonic sensor 10 according to the first embodiment of the present invention. Schematic diagram of the manufacturing process steps. The method of manufacturing the ultrasonic sensor 10 of the first embodiment of the present invention includes:

Step S401: As shown in FIG. 5, a substrate 12 is provided. The substrate 12 is a TFT (thin film transistor) array substrate; the substrate 12 is cleaned and dried; the substrate 12 defines a sensing area 121 and a peripheral area 122 adjacent to the sensing area 121.

In this embodiment, a thin film transistor (TFT) 121 (as shown in FIG. 2) arranged in a complex matrix may be formed on the surface of the substrate 12.

Step S402: As shown in FIG. 6, a mask 16 is formed on the substrate 12. The mask 16 includes an opaque region 161 and a transparent region 162. The opaque region 161 covers the peripheral region 122 of the substrate 12, and the transparent region 162 covers the substrate 12's sensing area 121.

In this embodiment, the light-transmitting area 162 of the mask 16 is hollowed out so that light can pass through the light-transmitting area 162.

In the present embodiment, the mask 16 is a peelable mask 16 covering the surface of the substrate 12, but it is not limited thereto. In other embodiments, the mask 16 may also be a photoresist that can be removed by etching, or a metal mask.

Step S403: As shown in FIG. 7, a piezoelectric polymer material (for example, PVDF-TrFE copolymer) is coated on the sensing area 121, and the mask 16 is removed to form a piezoelectric layer 131 located in the sensing area 121.

In this embodiment, after coating the piezoelectric polymer material (for example, PVDF-TrFE copolymer) on the sensing area 121, it also includes soft baking the piezoelectric polymer material to reduce the concentration of residual solvent in the piezoelectric polymer material and prevent Form bubble crystals, improve adhesion and prevent them from dissolving in other coating processes; then crystallize and anneal piezoelectric polymer materials and polarized piezoelectric polymer materials to improve the performance of the formed piezoelectric layer 131.

Before the piezoelectric layer 131 is formed, the method of manufacturing the ultrasonic sensor 10 of the first embodiment of the present invention further includes forming an adhesive layer 15 on the sensing area 21 (see FIG. 2 ). After the adhesive layer 15 is formed, the piezoelectric layer 131 is formed on the surface of the adhesive layer 15 away from the substrate 12. In this embodiment, the adhesive layer 15 is an anisotropic conductive adhesive.

Step S404: As shown in FIG. 8, an electrode layer 132 covering the piezoelectric layer 131 is formed; the piezoelectric layer 131 and the electrode layer 132 serve as the ultrasonic sensing layer 13 of the ultrasonic sensor 10, and the ultrasonic sensing layer 13 is used for transmission And receive ultrasonic signals.

The method of manufacturing the ultrasonic sensor 10 according to the first embodiment of the present invention further includes forming a trace (not shown) electrically connected to the electrode layer 132 in the peripheral region 122 and away from the ultrasonic sensor layer 13 on the substrate 12 A protective layer 11 is formed on one side of the substrate, and a flexible layer 14 is formed on the side of the ultrasonic sensing layer 13 away from the substrate 12. In this embodiment, the ultrasonic sensor 10 is a patch type, and the protective layer 11, the substrate 12, the ultrasonic sensing layer 13 and the soft layer 14 are all flexible.

It can be understood that, in other embodiments, the ultrasonic sensor 10 may be a non-flexible curved sensor. The protective layer 11 may be made of other materials such as glass and plastic. The protective layer 11 is combined with other components such as the substrate 12 and the ultrasonic sensing layer 13 by In-Mold Decoration (IMD) technology.

Please refer to FIGS. 9-10. FIG. 9 is a manufacturing flowchart of the ultrasonic sensor 10 of the second embodiment of the present invention. FIG. 10 is a structure of step S905 of manufacturing the ultrasonic sensor 10 of the second embodiment of the present invention. Schematic.

The steps S901-S904 of manufacturing the ultrasonic sensor 10 of the second embodiment of the present invention are similar to the steps S401-S404 of manufacturing the ultrasonic sensor 10 of the first embodiment of the present invention, and will not be repeated here. In this embodiment, the method of manufacturing the ultrasonic sensor 10 of the second embodiment of the present invention further includes:

Step S905: As shown in FIG. 10, after forming the electrode layer 132 covering the piezoelectric layer 131, the ultrasonic sensing layer 13 is patterned to form a plurality of independent sensing units 130.

In this embodiment, each sensing unit 130 includes a piezoelectric layer 131 and an electrode layer 132 that are stacked. The complex sensing units 130 each transmit ultrasonic waves to form a beam forming mode. In this beamforming mode, for a sensing unit 130, the ultrasound transmitted by it is weighted and retransmitted with the ultrasound transmitted by the two adjacent sensing units 130 to form a narrow transmit beam, thereby enhancing The transmitted signal of the ultrasonic sensing layer 13 as a whole also correspondingly enhances the received signal strength of the ultrasonic sensing layer 13.

Please refer to FIGS. 11-16. FIG. 11 is a manufacturing flowchart of the ultrasonic sensor 10 according to a modified embodiment of the present invention. 12 to 16 are schematic structural diagrams of manufacturing steps of manufacturing an ultrasonic sensor 10 according to a modified embodiment of the present invention. In this embodiment, the ultrasonic sensor 10 can be manufactured in batches, the specific method is as follows:

Step S1101: As shown in FIG. 12, a mother substrate 120 is provided to clean and dry the mother substrate 120; wherein, the mother substrate 120 includes a plurality of substrates 12, the substrate 12 is a TFT (thin film transistor) array substrate, and each substrate 12 is defined with a sensor The area 121 and the peripheral area 122 adjacent to the sensing area 121.

Step S1102: As shown in FIG. 13, a mask 16 is formed on the mother substrate 120. The mask 16 includes an opaque region 161 and a light-transmitting region 162 hollowed out. The opaque region 161 covers the peripheral region 122 of each substrate 12. The light transmitting area 162 covers the sensing area 121 of each substrate 12.

Step S1103: As shown in FIG. 14, a piezoelectric polymer material (for example, PVDF-TrFE copolymer) is coated on each sensing area 121, and the mask 16 is removed to form a piezoelectric layer 131 on each sensing area 121.

In this embodiment, after the piezoelectric polymer material (for example, PVDF-TrFE copolymer) is coated on the sensing area 121, a soft baked piezoelectric polymer material is also included to reduce the concentration of residual solvent in the piezoelectric polymer material and prevent the formation of bubbles Crystallizing, improving adhesion and preventing its dissolution in other coating processes; then crystallizing and annealing the piezoelectric polymer material and the polarized piezoelectric polymer material to improve the performance of the formed piezoelectric layer 131.

Before the piezoelectric layer 131 is formed, the method of manufacturing the ultrasonic sensor 10 of the first embodiment of the present invention further includes forming an adhesive layer 15 on the sensing area 21 (see FIG. 2 ). After the adhesive layer 15 is formed, the piezoelectric layer 131 is formed on the surface of the adhesive layer 15 away from the substrate 12. In this embodiment, the adhesive layer 15 is an anisotropic conductive adhesive.

Step S1104: as shown in FIG. 15, an electrode layer 132 covering the piezoelectric layer 131 is formed; each piezoelectric layer 131 and the corresponding electrode layer 132 serve as the ultrasonic sensing layer 13, and the ultrasonic sensing layer 13 is used to transmit and receive ultrasound Sonic signal

Step S1105: As shown in FIG. 16, the mother substrate 120 is cut along the edges of the plurality of substrates 12 to form a plurality of ultrasonic sensors 10.

It can be understood that the method of manufacturing the ultrasonic sensor 10 of this embodiment further includes forming a trace (not shown) electrically connected to the electrode layer 132 in the peripheral region 122 and away from the ultrasonic sensor layer on the substrate 12 A protective layer 11 is formed on one side of 13, and a soft layer 14 is formed on the side of the ultrasonic sensing layer 13 away from the substrate 12.

The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced, and Without departing from the spirit and scope of the technical solution of the present invention.

100: Ultrasonic sensing device 10: Ultrasonic sensor 11: protective layer 12: substrate 121: Thin film transistor 120: Mother board 13: Ultrasonic sensing layer 130: sensing unit 131: Piezo layer 132: electrode layer 14: Soft layer 15: adhesive layer 16: Mask 161: opaque area 162: Translucent area

FIG. 1 is a schematic perspective view of an ultrasonic sensing device according to a first embodiment of the invention.

FIG. 2 is a schematic cross-sectional view of FIG. 1 taken along line II-II.

3 is a schematic cross-sectional structural diagram of an ultrasonic sensor according to a second embodiment of the present invention.

FIG. 4 is a manufacturing flowchart of the ultrasonic sensor according to the first embodiment of the present invention.

FIG. 5 to FIG. 8 are schematic structural diagrams of the manufacturing process steps for manufacturing the ultrasonic sensor according to the first embodiment of the present invention.

9 is a manufacturing flowchart of an ultrasonic sensor according to a second embodiment of the invention.

10 is a schematic structural view of step S905 of manufacturing an ultrasonic sensor according to a second embodiment of the present invention.

FIG. 11 is a manufacturing flowchart of an ultrasonic sensor according to a modified embodiment of the present invention.

12 to 16 are schematic structural views of manufacturing steps of manufacturing an ultrasonic sensor according to a modified embodiment of the present invention.

10: Ultrasonic sensor

11: protective layer

12: substrate

121: Thin film transistor

13: Ultrasonic sensing layer

131: Piezo layer

132: electrode layer

14: Soft layer

15: adhesive layer

Claims (10)

An ultrasonic sensor is improved, comprising: a substrate; an ultrasonic sensing layer, the substrate is used to support the ultrasonic sensing layer; the ultrasonic sensing layer includes a piezoelectric layer and a laminated layer At least one electrode layer, the ultrasonic sensing layer is used to send and receive ultrasonic signals. The ultrasonic sensor according to claim 1, wherein the ultrasonic sensor further includes a control unit that controls the ultrasonic sensing layer to transmit and receive ultrasonic signals in a time-sharing manner. The ultrasonic sensor according to claim 1, wherein the ultrasonic sensing layer includes a plurality of mutually independent sensing units, and each sensing unit includes the piezoelectric layer and at least one electrode layer. The ultrasonic sensor according to claim 1, wherein the ultrasonic sensor further includes a soft layer stacked on the ultrasonic sensor layer. The ultrasonic sensor according to claim 1, wherein the substrate is a flexible material. A method for manufacturing an ultrasonic sensor, comprising: providing a substrate, the substrate is a thin film transistor array substrate, a sensing area and a peripheral area adjacent to the sensing area are defined on the substrate; on the substrate Forming a mask, the mask including an opaque region and a transparent region, the opaque region covering the peripheral region of the substrate, the transparent region covering the sensing region of the substrate; coating a piezoelectric polymer material In the sensing area, the mask is removed to form a piezoelectric layer located in the sensing area; an electrode layer covering the piezoelectric layer is formed; the piezoelectric layer and the electrode layer are used for ultrasonic sensing Layer, the ultrasound sensing layer is used to send and receive ultrasound signals. The method for manufacturing an ultrasonic sensor according to claim 6, wherein after forming the electrode layer covering the piezoelectric layer, the ultrasonic sensing layer is patterned to form a plurality of independent sensing units. The method for manufacturing an ultrasonic sensor according to claim 6, wherein: after the piezoelectric polymer material is coated on the sensing area, the piezoelectric polymer material is soft baked, crystallized and annealed to process the piezoelectric polymer material. The method for manufacturing an ultrasonic sensor according to claim 8, wherein: before forming the piezoelectric layer, an adhesive layer is formed on the sensing area, and the piezoelectric layer is formed on the adhesive layer away from the Said one side of the substrate. A method for manufacturing an ultrasonic sensor includes: providing a mother substrate, the mother substrate includes a plurality of substrates, the substrate is a thin film transistor array substrate, each of the substrates defines a sensing area and the A peripheral area adjacent to the sensing area; forming a mask on the mother substrate, the mask including an opaque area and a transparent area, the opaque area covering the peripheral area of each of the substrate, the The light-transmitting area covers the sensing area of each of the substrates; the piezoelectric polymer material is coated on each of the sensing areas, and the mask is removed to form a piezoelectric layer located in each of the sensing areas; An electrode layer of the piezoelectric layer, each of the piezoelectric layer and the corresponding electrode layer serving as an ultrasonic sensing layer, the ultrasonic sensing layer is used to send and receive ultrasonic signals; along the plurality of substrates The edge of the mother substrate is cut to form a plurality of ultrasonic sensors.

Images