Patent Translate Powered by EPO and Google Notice This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate, complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or financial decisions, should not be based on machine-translation output. DESCRIPTION JP2017118240 Abstract: The present invention provides an electret sensor element, a matrix sensor, and a method of manufacturing the same, which can be reduced in thickness and size by a simple process and can be easily matrixed. An electret sensor element for converting vibration into an electric signal, comprising: a vibrating electrode having a flat vibrating surface at no load, a fixed electrode formed on a substrate, and a space between the vibrating electrode and the fixed electrode Comprising an insulating layer disposed in the air gap and an electret layer storing charges, and an insulating layer insulated from the vibrating electrode and the fixed electrode, and a thin film transistor for impedance conversion formed on the same surface as the fixed electrode It is. [Selected figure] Figure 1 Electret sensor element, matrix sensor and method for manufacturing them, and matrix sensor circuit [0001] The present invention relates to an electret sensor element for converting vibration into an electrical signal, a matrix sensor in which the electret sensor elements are arranged in a matrix, a method of manufacturing them, and a matrix sensor circuit using the matrix sensor. [0002] 2. Description of the Related Art Electret sensor elements that convert vibrations into electrical signals are known. 04-05-2019 1 Here, the electret sensor element has a capacitor structure in which an air gap and an electret layer storing charges are disposed between the fixed electrode and the vibrating electrode, and the change in the inter-electrode distance due to the vibration of the vibrating electrode , As a change in the voltage between the electrodes. [0003] Although the electret sensor element can detect minute vibrations, the electric signal output from the electret sensor element is weak. Therefore, in order to reduce the influence of noise superimposed in the transmission path to the AD converter provided in the subsequent stage, an FET (Field Effect Transistor) for impedance conversion is provided in the vicinity of the fixed electrode, and the electric signal from the electret sensor element Is amplified. [0004] As such an electret sensor element, a vibrating electrode having a flat vibrating surface at no load, a vibrating-layer insulating layer provided on the lower surface of the vibrating electrode, and an electret layer facing the vibrating electrode via an air gap. There has been proposed an ultrasonic probe provided with a back electrode (fixed electrode) in contact with the lower surface of the electret layer and an amplifier (FET) connected between the vibrating electrode and the back electrode (see, for example, Patent Document 1) ). [0005] WO 2009/125773 [0006] However, the prior art has the following problems. That is, in the electret sensor element of Patent Document 1, the back surface (surface opposite to the vibration electrode) of the back electrode is a separate component from the sensor unit including the vibration electrode, the vibration layer insulating layer, the electret layer and the back electrode. And the FET for impedance conversion is connected by another process. 04-05-2019 2 [0007] Therefore, there is a problem that the thickness of the electret sensor element is increased and enlarged, and the manufacturing process of the electret sensor element is complicated. In addition, when this electret sensor element is formed into a matrix to form a matrix sensor, an FET is required for each sensor unit, and wiring crosses occur and a separate circuit board for wiring is required, so the thickness is further increased. There is a problem of increasing in size more than ever. [0008] The present invention has been made to solve the problems as described above, and it is possible to realize thinning and downsizing by a simple process, and an electret sensor element, which is easy to form into a matrix, a matrix sensor, and those The purpose is to obtain a manufacturing method. [0009] An electret sensor element according to the present invention is an electret sensor element that converts vibration into an electric signal, and includes a vibrating electrode having a flat vibrating surface at no load, a fixed electrode formed on a substrate, and a vibrating electrode. An insulating layer formed of an air gap and an electret layer storing charges, which is disposed between the fixed electrode and the vibrating electrode and the fixed electrode, and a thin film transistor for impedance conversion formed on the same surface as the fixed electrode. (TFT: Thin Film Transistor). [0010] A matrix sensor according to the present invention has the above-described electret sensor elements arranged in a matrix. [0011] A method of manufacturing an electret sensor element according to the present invention is a method of manufacturing an electret sensor element for converting vibration into an electric signal, and the steps of forming a fixed electrode and a thin film transistor for impedance conversion in the same process on a substrate; Forming an air gap on the electrode and the thin 04-05-2019 3 film transistor, forming an electret layer storing charges on the spacer, forming an insulating layer on the electret layer, and forming the insulating layer on the insulating layer Forming a vibrating electrode having a flat vibrating surface at no load. [0012] A method of manufacturing a matrix sensor according to the present invention is a method of manufacturing a matrix sensor in which electret sensor elements for converting vibrations into electric signals are arranged in a matrix, and a set of fixed electrodes and thin film transistors for impedance conversion is formed on a substrate. A plurality of steps of forming in the same process, disposing a spacer forming an air gap on the plurality of fixed electrodes and thin film transistors, and forming an electret layer on which the charge is stored. And forming an insulating layer on the electret layer and forming a vibrating electrode having a flat vibration surface at no load on the insulating layer. [0013] According to the electret sensor element, the matrix sensor, and the method of manufacturing the same according to the present invention, the thin film transistor for impedance conversion is formed on the same surface as the fixed electrode in the same process. Therefore, it is possible to obtain an electret sensor element, a matrix sensor, and a method for manufacturing them, which can realize thinning and downsizing with a simple process, and can be easily matrixed. [0014] It is sectional drawing which shows the electret sensor element which concerns on Embodiment 1 of this invention. It is a top view which shows typically the relationship of the fixed electrode and TFT of the electret sensor element which concern on Embodiment 1 of this invention. It is a top view which shows the matrix sensor which arrange ¦ positioned the electret sensor 04-05-2019 4 element which concerns on Embodiment 1 of this invention in a matrix form. FIG. 6 is another cross-sectional view showing the electret sensor element in accordance with Embodiment 1 of the present invention. FIG. 6 is yet another cross-sectional view showing the electret sensor element in accordance with Embodiment 1 of the present invention. It is a top view which shows the matrix sensor circuit which used the matrix sensor. It is a top view which shows the matrix sensor circuit which concerns on Embodiment 2 of this invention. It is the equivalent circuit schematic which extracts and shows the electret sensor element of the matrix sensor circuit which concerns on Embodiment 2 of this invention. [0015] Hereinafter, preferred embodiments of an electret sensor element, a matrix sensor and a method for manufacturing them, and a matrix sensor circuit according to the present invention will be described using the drawings, but the same or corresponding parts in the respective drawings are identical A description will be given with reference numerals. [0016] The electret sensor element is a highly sensitive vibration sensor that can detect even ultrasonic waves. Specifically, it can realize the function of position (three-dimensional position) sensor using ultrasonic waves and the function of heart rate sensor, and by using TFT, it integrates with the current TFT type display device, It becomes possible to provide a functional display device. [0017] In addition, matrix formation can be applied to medical applications such as simple echo and industrial applications such as failure point diagnosis. Further, in the case of using a transparent electrode, it can be integrated with an LCD (Liquid Crystal Display), and can be applied to a wearable display device with a sensor or the like. 04-05-2019 5 [0018] Embodiment 1 FIG. 1 is a cross-sectional view showing an electret sensor element in accordance with Embodiment 1 of the present invention. FIG. 2 is a schematic view showing the relationship between the fixed electrode and the TFT of the electret sensor element in accordance with Embodiment 1 of the present invention. This electret sensor element is obtained by integrating the above-described FET for impedance conversion with a fixed electrode and a TFT at the same time, and integrating it with a sensor unit. [0019] In FIGS. 1 and 2, the electret sensor element 1 is fixed to a vibrating electrode 11 having a flat vibrating surface at no load, a fixed electrode 13 formed on a substrate 12 made of glass or a film, and the vibrating electrode 11. An air gap 14 disposed between the electrode 13 and an electret layer 15 storing electric charge, and connected to the insulating layer 16 insulated from the vibrating electrode 11 and the fixed electrode 13 and the fixed electrode 13, the fixed electrode 13 And a TFT 17 for impedance conversion formed on the same surface. [0020] Further, the insulating layer 16 includes a first insulating layer 18 provided on the surface on the fixed electrode 13 side of the vibrating electrode 11, an electret layer 15 provided on the surface on the fixed electrode 13 side of the first insulating layer 18, and an electret It has an air gap 14 disposed between the layer 15 and the fixed electrode 13. The air gap 14 is formed by the spacer 19. Further, the substrate 12 and the electret layer 15 are bonded by an adhesive 20. [0021] Here, for the vibrating electrode 11, the first insulating layer 18, and the electret layer 15, for example, an electrode is provided on one side of a material having a high insulation resistance, such as a PFA (tetrafluoroethylene-perfluoroalkylvinylether copolymer) film, and the other side. Is formed of an electretized film of a three-layer structure which is electretized by irradiation of an electron beam or the like. 04-05-2019 6 [0022] The air gap 14 is formed between the fixed electrode 13 and the TFT 17 and the electret layer 15 at an interval of 10 nm to 100 μm. Further, the spacer 19 is an insulating material having a high resistivity of about 10 <16> Ω so that the fixed electrode 13 and the electret layer 15 charged do not conduct. [0023] Hereinafter, the manufacturing process of the electret sensor device 1 shown in FIG. 1 will be described. First, the fixed electrode 13 and the TFT 17 are formed in the same process on the substrate 12 made of glass or film. At this time, a wire connecting the fixed electrode 13 and the TFT 17 is also formed simultaneously with the fixed electrode 13 and the TFT 17. [0024] Subsequently, the spacer 19 forming the air gap 14 is disposed on the fixed electrode 13 and the TFT 17. Next, the electretized film having the vibrating electrode 11, the first insulating layer 18 and the electret layer 15 is placed on the spacer 19. Subsequently, the periphery of the substrate 12 is sealed with an adhesive 20. [0025] In the electret sensor element 1 manufactured in this manner, the vibrating electrode 11 is connected to the ground, and the output from the TFT 17 is connected to an AD converter (not shown). A change in distance can be detected as a change in inter-electrode voltage. [0026] Thus, the FET for impedance conversion necessary for the electret sensor element can be formed 04-05-2019 7 of a TFT and integrated with the sensor unit. In addition, by forming the FET for impedance conversion with a TFT, it is possible to realize an ultra-compact FET with almost the same thickness and on substantially the same plane as the fixed electrode 13. [0027] FIG. 3 is a plan view showing a matrix sensor in which the electret sensor elements according to Embodiment 1 of the present invention are arranged in a matrix. In FIG. 3, only the fixed electrode 13 and the TFT 17 formed on the substrate 12 are shown. In FIG. 3, this matrix sensor 10 has a configuration in which a plurality of electret sensor elements 1 shown in FIG. 1 are arranged in a matrix. [0028] Hereinafter, the manufacturing process of the matrix sensor 10 shown in FIG. 3 will be described. First, a plurality of sets of fixed electrodes 13 and TFTs 17 are formed in a matrix on the substrate 12 made of glass or film in the same process. At this time, a wire connecting the fixed electrode 13 and the TFT 17 is also formed simultaneously with the fixed electrode 13 and the TFT 17. [0029] Subsequently, the spacer 19 forming the air gap 14 is disposed on the plurality of sets of the fixed electrode 13 and the TFT 17. Next, the electretized film having the vibrating electrode 11, the first insulating layer 18 and the electret layer 15 is placed on the spacer 19. Subsequently, the periphery of the substrate 12 is sealed with an adhesive 20. [0030] Thus, the spacer 19 forming the air gap 14 is disposed on the entire surface of the substrate 12 on which a plurality of sets of the fixed electrode 13 and the TFT 17 are formed, and the electretized film is mounted on the spacer 19. The matrix sensor 10 can be configured by a 04-05-2019 8 simple process. [0031] As described above, according to the first embodiment, the TFT for impedance conversion is formed on the same surface as the fixed electrode in the same process. Therefore, it is possible to obtain an electret sensor element, a matrix sensor, and a method for manufacturing them, which can realize thinning and downsizing with a simple process, and can be easily matrixed. [0032] In the first embodiment, it has been described that the air gap 14 is disposed between the fixed electrode 13 and the TFT 17 and the electret layer 15 in FIG. However, when a strong force is applied to the vibrating electrode 11, the electret layer 15 may come into contact with the fixed electrode 13 and a discharge may occur. [0033] Therefore, as shown in FIG. 4, by providing the second insulating layer 21 between the fixed electrode 13 and the TFT 17 and the spacer 19, the electret layer is obtained even when a strong force is applied to the vibrating electrode 11. The contact 15 can be prevented from contacting the fixed electrode 13. [0034] Further, in FIG. 4, the electret layer 15 and the air gap 14 are disposed between the first insulating layer 18 and the second insulating layer 21. However, as shown in FIG. 5, the spacers forming the air gap 14 may be electretized electretized spacers 22. 04-05-2019 9 [0035] Second Embodiment FIG. 6 is a plan view showing a matrix sensor circuit using the matrix sensor shown in FIG. As shown in FIG. 6, in this matrix sensor circuit, an AD converter 23 that digitizes the output from the TFT 17 is required for each electret sensor element 1. Therefore, in this embodiment, the reduction of the number of AD converters 23 will be described. [0036] FIG. 7 is a plan view showing a matrix sensor circuit according to Embodiment 2 of the present invention. In FIG. 7, this matrix sensor circuit includes a matrix sensor 10, an AD converter 23, a shift register 24 composed of a plurality of D-type flip flops (DFFs), and a logic circuit 25 for signal processing. [0037] Here, with respect to the TFT 17 of each electret sensor element 1, a plurality of vertical wirings 26 and a plurality of horizontal wirings 27 which are insulated from the plurality of vertical wirings 26 and are orthogonal to each other are provided. Further, at the intersections of the plurality of vertical wires 26 and the plurality of horizontal wires 27, TFTs for switches are provided. [0038] FIG. 8 is an equivalent circuit diagram showing an electret sensor element of a matrix sensor circuit according to Embodiment 2 of the present invention. In FIG. 8, the electret sensor element 1 is connected to a switch TFT 28 formed at the intersection of the vertical wire 26 and the horizontal wire 27. [0039] 04-05-2019 10 In this equivalent circuit, when a selection signal is applied to the horizontal wiring 27 from the shift register 24, a signal after impedance conversion, which is output from the TFT 17 according to the change in inter-electrode voltage generated by the vibration of the vibrating electrode 11, is , And the vertical wiring 26. As described above, by providing the vertical wires 26, the horizontal wires 27 and the TFTs 28 for switches, it is possible to sense only the selected row, and the number of AD converters 23 can be reduced. [0040] Further, in the matrix sensor circuit shown in FIG. 8, the TFT 17, the TFT 18 and the shift register 24 can be formed in the same process as the fixed electrode 13. Therefore, the matrix sensor circuit can be configured by a simple process. [0041] Reference Signs List 1 electret sensor element, 10 matrix sensor, 11 vibrating electrode, 12 substrate, 13 fixed electrode, 14 air gap, 15 electret layer, 16 insulating layer, 17 TFT, 18 first insulating layer, 19 spacer, 20 adhesive, 21 first 2 insulating layers, 22 electret spacers, 23 AD converters, 24 shift registers, 25 logic circuits, 26 vertical wires, 27 horizontal wires, 28 TFTs. 04-05-2019 11
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