pressure sensor

Abstract

A pressure sensor includes a substrate, a pressure sensing unit, a first signal line, a second signal line, an elastic body, and a counter substrate. The pressure sensing unit includes a first and a second resistor connected in series, a third and a fourth resistor connected in series, a first switching element, and a second switching element. The first and the second resistor are connected to the third and the fourth resistor. The first switching element is electrically connected between the first and the second resistor. The second switching element is electrically connected between the third and the fourth resistor. The first signal line is electrically connected between the first and the fourth resistor. The second signal line is electrically connected between the second and the third resistor. The elastic body includes a cavity. The first to the fourth resistor overlap the cavity.

Description

Technical Field

[0001] This invention relates to a pressure sensor. Background Technology

[0002] Currently, there are many different types of pressure sensors on the market. Common pressure sensors include capacitive, piezoelectric, and piezoresistive sensors. Capacitive sensors are prone to coupling between touch signals and other signals within the sensor, making it difficult to accurately measure minute pressures. Piezoelectric sensors sense pressure by measuring the current generated by changes in pressure; therefore, they cannot be used to measure static forces. Piezoresistive pressure sensors utilize the inherent properties of the material itself for pressure sensing. Generally, piezoresistive pressure sensors are manufactured by forming integrated circuits on silicon wafers; however, because silicon wafers are rigid materials, piezoresistive pressure sensors can only measure force in a single direction. Summary of the Invention

[0003] This invention provides a pressure sensor that can improve the sensitivity of pressure sensing.

[0004] At least one embodiment of the present invention provides a pressure sensor. The pressure sensor includes a substrate, a pressure sensing unit, a first signal line, a second signal line, an elastomer, and a counter substrate. The pressure sensing unit is located on the substrate. The pressure sensing unit includes a first resistor and a second resistor connected in series, a third resistor and a fourth resistor connected in series, a first switching element, and a second switching element. The first resistor and the second resistor are connected in parallel with the third resistor and the fourth resistor. The first switching element is electrically connected between the first resistor and the second resistor. The second switching element is electrically connected between the third resistor and the fourth resistor. The first signal line is electrically connected between the first resistor and the fourth resistor. The second signal line is electrically connected between the second resistor and the third resistor. The elastomer is located on the substrate and includes a cavity. The first resistor, the second resistor, the third resistor, and the fourth resistor at least partially overlap the cavity. The counter substrate is located on the elastomer.

[0005] Based on the above, the sensitivity of pressure sensing can be improved by setting up an elastomer and a cavity. Attached Figure Description

[0006] Figures 1A to 1C This is a cross-sectional schematic diagram of a method for manufacturing a pressure sensor according to an embodiment of the present invention.

[0007] Figure 2 yes Figure 1C A top view of the pressure sensor.

[0008] Figure 3 This is a cross-sectional schematic diagram of a pressure sensor according to an embodiment of the present invention.

[0009] Figure 4 This is a cross-sectional schematic diagram of a pressure sensor according to an embodiment of the present invention.

[0010] Figure 5 This is a cross-sectional schematic diagram of a pressure sensor according to an embodiment of the present invention.

[0011] Figure 6 This is a circuit diagram of a pressure sensor according to an embodiment of the present invention.

[0012] Figure 7 yes Figure 6 The signal waveform diagram of the pressure sensor.

[0013] Figure 8 This is a line graph of voltage change versus pressure of a pressure sensor according to some embodiments of the present invention.

[0014] Figure 9 This is a circuit diagram of a pressure sensor according to an embodiment of the present invention.

[0015] Figure 10 This is a circuit diagram of a pressure sensor according to an embodiment of the present invention.

[0016] Explanation of reference numerals in the attached figures:

[0017] 10, 20, 30, 40: Pressure sensors

[0018] 100: Substrate

[0019] 200: Circuit Structure

[0020] 210, 212, 214: Conductors

[0021] 220: First insulating layer

[0022] 230: Second insulating layer

[0023] 232: Groove

[0024] 240: Third insulation layer

[0025] 242: First source / drain

[0026] 243: First Ohmic Contact Layer

[0027] 244: Semiconductor Channel

[0028] 246: Gate

[0029] 248: Second source / drain

[0030] 249: Second Ohmic Contact Layer

[0031] 250: Connecting pad

[0032] 300: Elastomer

[0033] 310: Cavity

[0034] 400: Opposing substrate

[0035] 500: Flexible film

[0036] BF: Buffer layer

[0037] C: Carrier plate

[0038] D1: Depth

[0039] D1-1~Dn-1: First signal sensing line

[0040] D1-2~Dn-2: Second signal sensing line

[0041] DT: Distance

[0042] E1: First Direction

[0043] E2: Second Direction

[0044] G1-1~Gn-1: Gate signal lines

[0045] G1-2~Gn-2: First signal line

[0046] GND: Second signal line

[0047] ND: Normal direction

[0048] R: Resistance

[0049] RU: Pressure Sensing Unit

[0050] R1: First resistor

[0051] R2: Second resistor

[0052] R3: Third resistor

[0053] R4: Fourth resistor

[0054] S: Size

[0055] T: Switching element

[0056] T1: First switching element

[0057] T2: Second switching element

[0058] T3: Third switching element

[0059] T1~Tn, Tn+1: Scan time

[0060] W1: Width Detailed Implementation

[0061] Figures 1A to 1C This is a cross-sectional schematic diagram of a method for manufacturing a pressure sensor 10 according to an embodiment of the present invention. Please refer to [the original text]. Figure 1A A substrate 100 is formed on a carrier plate C. Methods of forming the substrate 100 include attachment or coating. In some embodiments, the carrier plate C includes a rigid substrate, and the material of the carrier plate C includes, for example, glass, quartz, acrylic, silicon wafer, or other suitable materials for carrying the substrate 100. The substrate 100 is, for example, a flexible substrate or a stretchable substrate. For example, the materials of flexible and stretchable substrates include polyimide (PI), polydimethylsiloxane (PDMS), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyester (PES), polymethylmethacrylate (PMMA), polycarbonate (PC), polyurethane (PU), fiber-reinforced plastic (FRP), or other suitable materials. In some embodiments, the thickness of the substrate 100 is from 1 micrometer to 50 micrometers.

[0062] A circuit structure 200 is formed on the substrate 100. In this embodiment, the circuit structure 200 includes a wire 210, a first insulating layer 220, and multiple resistors (including a first resistor R1, a second resistor R2, etc.). Figure 2 ), third resistor R3 and fourth resistor R4 (please refer to) Figure 2 A first insulating layer 220 is formed on the substrate 100 and covers the wire 210. A resistor is formed on the first insulating layer 220 and electrically connected to the wire 210. For example, a portion of the resistor is electrically connected to the wire 210 through a conductive via. A second insulating layer 230 is formed on the first insulating layer 220 and covers the resistor.

[0063] In this embodiment, the conductor 210, the first insulating layer 220, the resistor, and the second insulating layer 230 are formed in sequence, but the present invention is not limited thereto. In other embodiments, the formation order of the conductor 210, the first insulating layer 220, the resistor, and the second insulating layer 230 can be adjusted as needed.

[0064] In some embodiments, the first resistor R1 and the second resistor R2 (please refer to...) Figure 2 ), third resistor R3 and fourth resistor R4 (please refer to) Figure 2 The materials of each insulating layer 220 and the second insulating layer 230 may be metallic, semiconductor, or other suitable materials. Semiconductor materials include, for example, polycrystalline silicon, metal oxide semiconductors, or other materials. Polycrystalline silicon includes, for example, microcrystalline silicon or nanocrystalline silicon. In some embodiments, the materials of the first insulating layer 220 and the second insulating layer 230 may be organic or inorganic. In some embodiments, the material of the wire 210 may be metallic, semiconductor, or other suitable materials.

[0065] In some embodiments, the circuit structure 200 may further include more insulating layers, more wires, multiple active elements (not shown), and / or multiple passive elements (not shown). The active elements (not shown) may be switching elements or other types of active elements. Switching elements are, for example, thin-film transistors.

[0066] In this embodiment, the circuit structure 200 includes a plurality of pressure sensing units RU. The pressure sensing units RU are located on the substrate 100, and each pressure sensing unit RU includes a first resistor R1 and a second resistor R2 (see reference). Figure 2 ), third resistor R3 and fourth resistor R4 (please refer to) Figure 2 ).

[0067] Please refer to the following: Figure 1B An elastomer 300 is formed on the substrate 100. In this embodiment, the elastomer 300 is formed on the circuit structure 200. In some embodiments, the material of the elastomer 300 may be an organic material or an inorganic material.

[0068] The elastomer 300 includes a plurality of cavities 310. In some embodiments, the elastomer 300 includes a photosensitive material, and the method of forming the elastomer 300 includes a coating process, an exposure and development process, and other suitable processes, but the invention is not limited thereto. In other embodiments, the elastomer 300 includes an inorganic material, and the method of forming the elastomer 300 includes a coating process, an etching process, and other suitable processes. In other words, the cavities 310 of the elastomer 300 can be formed by an exposure and development process and / or an etching process.

[0069] In this embodiment, the sidewall of cavity 310 is sloping, but the invention is not limited thereto. In other embodiments, the sidewall of cavity 310 includes a stepped or vertical type (the sidewall is perpendicular to the circuit structure 200).

[0070] Figure 2 This is a top view of a pressure sensor 10 according to an embodiment of the present invention, wherein... Figure 1C It is along Figure 2 A schematic cross-sectional view of line A-A'. (Continue) Figure 1B Please refer to the steps. Figure 1C as well as Figure 2 The opposing substrate 400 is attached to the elastomer 300 by adhesive, vacuum bonding, or atmospheric bonding / bonding. In some embodiments, the carrier plate C is removed before or after the opposing substrate 400 is attached to the elastomer 300. In some embodiments, the entire stacked structure is cut before or after the carrier plate C is removed to obtain a pressure sensor 10 of appropriate size. In some embodiments, at least one side of the opposing substrate 400 has an adhesive layer (not shown).

[0071] In some embodiments, the opposing substrate 400 may be a rigid substrate, such as glass fiber, metal, ceramic, organic material, or other rigid material, but the present invention is not limited thereto. In other embodiments, the opposing substrate 400 may be, for example, a flexible substrate or a stretchable substrate. For example, the materials of flexible substrates and stretchable substrates include polyimide, polydimethylsiloxane, polyethylene terephthalate, polyethylene glycol dicarboxylate, polyester, polymethyl methacrylate, polycarbonate, polyurethane, glass fiber reinforced plastic, or other suitable materials. In some embodiments, the hardness of the opposing substrate 400 is greater than the hardness of the substrate 100; or the hardness of the substrate 400 is the same as the hardness of the substrate 100, but the thickness of the substrate 400 is greater than or equal to the thickness of the substrate 100. In some embodiments, in addition to attaching the opposing substrate 400 to the elastomer 300, other flexible films (not shown) may be attached to the back side of the substrate 100 by adhesive, vacuum bonding, or bonding.

[0072] After the opposing substrate 400 is provided on the elastomer 300, a flexible printed circuit board (not shown) is bonded to the pressure sensor 10, and the system circuit board (not shown) or chip (not shown) is electrically connected to the pressure sensing unit RU of the pressure sensor 10 through the flexible printed circuit board, and then pressure detection can be performed.

[0073] The pressure sensing unit RU includes a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4. In this embodiment, multiple pressure sensing units RU are arranged in an array along a first direction E1 and a second direction E2 perpendicular to the first direction E1, thereby obtaining a high-resolution pressure sensor 10.

[0074] In this embodiment, on the normal direction ND of the surface of the substrate 100, each cavity 310 overlaps with a corresponding pressure sensing unit RU, wherein the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 of each pressure sensing unit RU at least partially overlap the corresponding cavity 310. In this embodiment, the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 do not partially overlap the corresponding cavity 310. In other words, in the top view, the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 each extend from outside the corresponding cavity 310 into the corresponding cavity 310 and partially overlap the edge of the corresponding cavity 310.

[0075] In this embodiment, the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 are all separated from the cavity 310 by an insulating layer (second insulating layer 230). In other words, in this embodiment, the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 are all disposed outside the cavity 310. In other embodiments, the second insulating layer 230 is omitted, or at least one of the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 is formed on the second insulating layer 230, so that at least a portion of the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 is located inside the cavity 310. In some embodiments, the elastomer 300 is formed directly on the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, and the first insulating layer 220.

[0076] In some embodiments, the dimensions S of the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 are each from 1 micrometer to 250 micrometers. In some embodiments, the length by which the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 overlap with the edge of the cavity 310 is 0 to 30 micrometers. In other embodiments, the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 are formed on the outside of the cavity 310, and the horizontal distance between them and the edge of the cavity 310 is 3 micrometers to 100 micrometers.

[0077] In some embodiments, the width W1 of each cavity 310 is 300 micrometers to 1000 micrometers. In some embodiments, the distance DT between cavities 310 is 50 micrometers to 300 micrometers. In some embodiments, the distance between the centers of cavities 310 is 10 micrometers to 2000 micrometers. In some embodiments, the depth D1 of each cavity 310 is 2 micrometers to 50 micrometers.

[0078] In some embodiments, the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 are respectively disposed on the four sides of the cavity 310. Since the edges of the cavity 310 are prone to generating large stresses when the pressure sensor 10 is subjected to force, placing the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 at positions overlapping the edges of the cavity 310 can improve the sensitivity of the pressure sensor 10. In this embodiment, the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 are respectively disposed on the inner sides of the four sides of the cavity 310, and partially overlap with the edges of the cavity 310. In some embodiments, the pressure sensor 10 is flexible or stretchable and is suitable for measuring normal forces, lateral forces, and / or bending forces applied to the pressure sensor 10. Furthermore, in some embodiments, both the front and back sides of the pressure sensor 10 can be used to measure pressure. In addition, compared to measuring pressure by detecting changes in capacitance, this embodiment measures pressure by detecting changes in resistance, which is less prone to inaccurate measurement results due to device degradation or signal coupling.

[0079] Figure 3 This is a schematic cross-sectional view of a pressure sensor according to an embodiment of the present invention. It should be noted that... Figure 3 The embodiments follow Figures 1A to 2 The component reference numerals and partial contents of the embodiments are described below, wherein the same or similar reference numerals are used to represent the same or similar components, and descriptions of the same technical content are omitted. For explanations of the omitted parts, please refer to the foregoing embodiments, and will not be repeated here.

[0080] Figure 3 Pressure sensor 20 and Figure 1C The main difference between the pressure sensor 10 and the pressure sensor 20 is that the pressure sensor 20 also includes a flexible film 500. The flexible film 500 is located on the back side of the substrate 100. The substrate 100 is located between the pressure sensing unit RU and the flexible film 500.

[0081] The flexible film 500 is attached to the substrate 100 by adhesive, vacuum bonding, or bonding. In some embodiments, the material of the flexible film 500 includes polyimide, polydimethylsiloxane, polyethylene terephthalate, polyethylene glycol dicarboxylate, polyester, polymethyl methacrylate, polycarbonate, polyurethane, glass fiber reinforced plastic, or other suitable materials. By attaching the flexible film 500 to the back side of the substrate 100, the sensitivity and accuracy of the pressure sensor 20 can be adjusted. In some embodiments, at least one side of the flexible film 500 has an adhesive layer (not shown).

[0082] Table 1 provides the hardness of flexible films 500 made of different materials and the sensitivity and accuracy of pressure sensors 20 containing flexible films 500 made of different materials. In Table 1, the material of the substrate 100 of the pressure sensor 20 is polyimide, and the material of the opposing substrate 400 is polyethylene terephthalate.

[0083] Table 1

[0084]

[0085] Table 1 shows that when the flexible film 500 is made of PU, the pressure sensor 20 has higher sensitivity, and when the flexible film 500 is made of PET, the pressure sensor 20 has higher accuracy. Therefore, pressure sensors 20 with different sensitivities can be obtained by replacing different flexible films 500.

[0086] Table 2 shows the deformation of flexible films 500 made of different materials and of different thicknesses under the same pressure. In Table 2, the pressure applied to the flexible film 500 is 40 kPa.

[0087] Table 2

[0088]

[0089]

[0090] As shown in Table 2, the thickness of the flexible film 500 is related to the amount of deformation produced when the flexible film 500 is compressed. Therefore, pressure sensors 20 with different characteristics can be obtained by adjusting the thickness of the flexible film 500.

[0091] Figure 4 This is a cross-sectional schematic diagram of a pressure sensor 30 according to an embodiment of the present invention. It should be noted that... Figure 4 The embodiments follow Figures 1A to 2The component reference numerals and partial contents of the embodiments are described below, wherein the same or similar reference numerals are used to represent the same or similar components, and descriptions of the same technical content are omitted. For explanations of the omitted parts, please refer to the foregoing embodiments, and will not be repeated here.

[0092] Figure 4 Pressure sensor 30 and Figure 1C The main difference between the pressure sensor 10 and the pressure sensor 30 is that in the circuit structure 200 of the pressure sensor 10, the wire 210 is formed first and then the resistor in the pressure sensing unit RU is formed; in the circuit structure 200 of the pressure sensor 30, the resistor in the pressure sensing unit RU is formed first and then the wire 210 is formed.

[0093] Please refer to Figure 4 In this embodiment, the resistor in the pressure sensing unit RU is formed on the substrate 100.

[0094] Figure 5 This is a schematic cross-sectional view of a pressure sensor 40 according to an embodiment of the present invention. It should be noted that... Figure 5 The embodiments follow Figures 1A to 2 The component reference numerals and partial contents of the embodiments are described below, wherein the same or similar reference numerals are used to represent the same or similar components, and descriptions of the same technical content are omitted. For explanations of the omitted parts, please refer to the foregoing embodiments, and will not be repeated here.

[0095] Please refer to Figure 5 In this embodiment, the circuit structure 200 is located on the substrate 100 and includes a buffer layer BF, multiple resistors R, wires 212 and 214, a first insulating layer 220, a second insulating layer 230, a third insulating layer 240, a pad 250, and a switching element T. The switching element T includes a gate 246, a semiconductor channel 244, a first source / drain 242, a second source / drain 248, a first ohmic contact layer 243, and a second ohmic contact layer 249.

[0096] A buffer layer BF is located on the substrate 100 and includes a single-layer or multi-layer structure. Multiple resistors R are located on the buffer layer BF. A first insulating layer 220 is located on the buffer layer BF and the resistors R. A gate 246 and a wire 212 are located on the first insulating layer 220. A second insulating layer 230 is located on the first insulating layer 220, the gate 246, and the wire 212. A semiconductor channel 244 is located on the second insulating layer 230 and overlaps the gate 246. A first source / drain 242, a second source / drain 248, and a wire 214 are located on the second insulating layer 230. The first source / drain 242 and the second source / drain 248 are electrically connected to the semiconductor channel 244, wherein a first ohmic contact layer 243 is located between the first source / drain 242 and the semiconductor channel 244, and a second ohmic contact layer 249 is located between the second source / drain 248 and the semiconductor channel 244. The second source / drain 248 and the wire 214 are electrically connected to the resistor R through a conductive via, and the wire 214 is electrically connected to the wire 212 through the conductive via. A third insulating layer 240 is located on the first source / drain 242, the second source / drain 248, and the wire 214. A pad 250 is electrically connected to the first source / drain 242. In some embodiments, an external flexible printed circuit board is electrically connected to the switching element T and the resistor R through the pad 250.

[0097] In some embodiments, after the formation of the first insulating layer 220, the resistance value of the resistor R is adjusted by ion doping, but the present invention is not limited thereto. In some embodiments, the resistor R comprises a metal oxide, and the second insulating layer 230 comprises hydrogen atoms; after the formation of the second insulating layer 230, a heat treatment is performed to diffuse hydrogen atoms into the resistor R, thereby adjusting the resistance value of the resistor R. Furthermore, the resistance value of the resistor R can also be adjusted by changing the type of gas, gas flow rate, gas ratio, or other parameters used in forming the resistor R.

[0098] In some embodiments, the material of the semiconductor channel 244 includes, for example, amorphous silicon, indium gallium zinc oxide, polycrystalline silicon, or other suitable materials. In some embodiments, the semiconductor channel 244 and the resistor R may comprise the same material.

[0099] In this embodiment, the second insulating layer 230 is patterned to have a groove 232 overlapping the cavity 310. The groove 232 design increases the strain of the resistance R of the pressure sensor 40 under pressure and the sensitivity of the Wheatstone bridge. In other embodiments, the aforementioned patterning process can be performed together with the first insulating layer 220, so that the groove 232 extends into the first insulating layer 220. In other embodiments, the aforementioned patterning process can be omitted to omit the manufacturing process of the groove 232.

[0100] In this embodiment, the second source / drain 248 and the wire 214 are electrically connected to the resistor R through two conductive holes passing through the first insulating layer 220 and the second insulating layer 230, but the invention is not limited thereto. In other embodiments, the groove 232 formed by the aforementioned patterning process extends directly to the surface of the resistor R, and the second source / drain 248 and the wire 214 contact the resistor R through the same groove 232.

[0101] In this embodiment, the single resistor R has a continuous structure, but the invention is not limited thereto. In other embodiments, the single resistor R may be formed by connecting multiple resistive materials together in series via wires, wherein the length and width of each of the multiple resistive materials may be from 1 micrometer to 200 micrometers. In some embodiments, when the single resistor R is formed by connecting multiple resistive materials together in series, the aforementioned multiple resistive materials may be arranged along the edge of the cavity 310.

[0102] The elastomer 300 is located on the third insulating layer 240 and has a plurality of cavities 310. The elastomer 300 exposes the pad 250. In this embodiment, the resistor R at least partially overlaps the cavity 310. In this embodiment, the resistor R is spaced from the cavity 310 by the first insulating layer 220, the second insulating layer 230, and the third insulating layer 240, but the invention is not limited thereto. In other embodiments, the resistor R is located between the first insulating layer 220 and the second insulating layer 230, between the second insulating layer 230 and the third insulating layer 240, or on the third insulating layer 240.

[0103] In some embodiments, gate 246 and wire 212 belong to the same film layer. In some embodiments, the first source / drain 242, the second source / drain 248, and wire 214 belong to the same film layer.

[0104] In this embodiment, the switching element T is a bottom-gate thin-film transistor, but the invention is not limited thereto. In other embodiments, the switching element T is a top-gate thin-film transistor, a dual-gate thin-film transistor, or other types of thin-film transistors. Furthermore, in some embodiments, the structure of the switching element T can be adjusted (e.g., changing the switching element T to a top-gate thin-film transistor) so that the semiconductor channel 244 and the resistor R are formed in the same process.

[0105] Figure 6 This is a circuit diagram of a pressure sensor according to an embodiment of the present invention. It must be noted that... Figure 6 The embodiments follow Figure 5 The component reference numerals and partial contents of the embodiments are described below, wherein the same or similar reference numerals are used to represent the same or similar components, and descriptions of the same technical content are omitted. For explanations of the omitted parts, please refer to the foregoing embodiments, and will not be repeated here.

[0106] Figure 6 The circuit structure 200 of the pressure sensor 40 is shown (see reference). Figure 5 The circuit layout is shown in [reference]. Please refer to [reference]. Figure 6 Multiple pressure sensing units RU are arranged in an array along the first direction E1 and the second direction E2, wherein each pressure sensing unit RU includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first switching element T1, and a second switching element T2.

[0107] Multiple gate signal lines G1-1 to Gn-1 and multiple first signal lines G1-2 to Gn-2 are electrically connected to the corresponding pressure sensing units RU. For example, the first row of pressure sensing units RU is electrically connected to the gate signal line G1-1 and the first signal line G1-2; the second row of pressure sensing units RU is electrically connected to the gate signal line G2-1 and the first signal line G2-2; and the nth row of pressure sensing units RU is electrically connected to the gate signal line Gn-1 and the first signal line Gn-2.

[0108] Each pressure sensing unit RU includes a first resistor R1 and a second resistor R2 connected in series, and a third resistor R3 and a fourth resistor R4 connected in series. The first resistor R1 and the second resistor R2 are connected in parallel with the third resistor R3 and the fourth resistor R4 to form a Wheatstone bridge.

[0109] Gate signal lines G1-1 to Gn-1 are electrically connected to the gates of the first switching element T1 and the second switching element T2. First signal lines G1-2 to Gn-2 are electrically connected between the first resistor R1 and the fourth resistor R4. Second signal line GND is electrically connected between the second resistor R2 and the third resistor R3. The second signal line GND may be connected to ground, for example.

[0110] In this embodiment, the gates of the first switching element T1 and the second switching element T2 of the pressure sensing units RU arranged in the same column in the second direction E2 are electrically connected to corresponding gate signal lines G1-1 to Gn-1. In this embodiment, the pressure sensing units RU arranged in the same column in the second direction E2 are electrically connected to corresponding first signal lines G1-2 to Gn-2. For example, the first column of pressure sensing units RU is electrically connected to gate signal line G1-1 and first signal line G1-2, the second column of pressure sensing units RU is electrically connected to gate signal line G2-1 and first signal line G2-2, and the nth column of pressure sensing units RU is electrically connected to gate signal line Gn-1 and first signal line Gn-2.

[0111] The first source / drain of the first switching element T1 is electrically connected between the first resistor R1 and the second resistor R2. The first source / drain of the second switching element T2 is electrically connected between the third resistor R3 and the fourth resistor R4. The second source / drain of the first switching element T1 is electrically connected to the first signal sensing lines D1-1 to Dn-1. The second source / drain of the second switching element T2 is electrically connected to the second signal sensing lines D1-2 to Dn-2. In other words, the first signal sensing lines D1-1 to Dn-1 are electrically connected to the first resistor R1 and the second resistor R2 of the corresponding pressure sensing unit RU through the first switching element T1, and the second signal sensing lines D1-2 to Dn-2 are electrically connected to the third resistor R3 and the fourth resistor R4 of the corresponding pressure sensing unit RU through the second switching element T2.

[0112] In this embodiment, the first switching element T1 of the pressure sensing units RU arranged in the same row in the first direction E1 is electrically connected to a corresponding first signal sensing line D1-1 to Dn-1, and the second switching element T2 of the pressure sensing units RU arranged in the same row in the first direction E1 is electrically connected to a corresponding second signal sensing line D1-2 to Dn-2. For example, the first switching element T1 and the second switching element T2 of the first row of pressure sensing units RU are electrically connected to the first signal sensing line D1-1 and the second signal sensing line D1-2, respectively; the first switching element T1 and the second switching element T2 of the second row of pressure sensing units RU are electrically connected to the first signal sensing line D2-1 and the second signal sensing line D2-2, respectively; and the first switching element T1 and the second switching element T2 of the nth row of pressure sensing units RU are electrically connected to the first signal sensing line Dn-1 and the second signal sensing line Dn-2, respectively.

[0113] Figure 7 yes Figure 6 The signal waveform diagram of the pressure sensor. Please refer to... Figure 7 During pressure sensing, a voltage is applied to the first signal lines G1-2 to Gn-2, creating a voltage difference between the first signal lines G1-2 to Gn-2 and the second signal line GND. In some embodiments, a constant DC voltage is applied to the first signal lines G1-2 to Gn-2.

[0114] Next, the gate signal lines G1-1 to Gn-1 are scanned sequentially. For example, there are a total of n gate signal lines G1-1 to Gn-1. Therefore, each scan cycle includes the first scan time T1 to the nth scan time Tn.

[0115] During the first scan time T1, gate signal line G1-1 is turned on, and other gate signal lines are turned off. During the second scan time T2, gate signal line G2-1 is turned on, and other gate signal lines are turned off. During the third scan time T3, gate signal line G3-1 is turned on, and other gate signal lines are turned off. During the nth scan time Tn, gate signal line Gn-1 is turned on, and other gate signal lines are turned off. After one scan cycle is completed, the scan restarts from gate signal line G1-1. For example, during the (n+1)th scan time Tn+1, gate signal line G1-1 is turned on again, and other gate signal lines are turned off.

[0116] During pressure sensing, the voltage difference between the first signal sensing lines D1-1 to Dn-1 and the second signal sensing lines D1-2 to Dn-2 is detected, and the pressure borne by the corresponding pressure sensing unit RU is calculated through the system circuit board (not shown) or chip (not shown).

[0117] Figure 8 This is a line graph showing the voltage change versus pressure of a pressure sensor according to some embodiments of the present invention. The voltage change is achieved through... Figure 6 and Figure 7 The measurement is performed using the first signal sensing lines D1-1 to Dn-1 and the second signal sensing lines D1-2 to Dn-2. In this embodiment, a voltage of 3.36V is applied to the first signal lines G1-2 to Gn-2, and the second signal line GND is grounded.

[0118] exist Figure 8 In the first to third embodiments, the pressure sensors have similar structures, the difference being that the pressure sensor in the first embodiment does not have a flexible film (the structure of the pressure sensor in the first embodiment is as follows). Figure 1C As shown), and the pressure sensors of the second and third embodiments have flexible films made of different materials (the structures of the pressure sensors of the second to third embodiments are as shown). Figure 3 (As shown).

[0119] In the pressure sensor of the first to fourth embodiments, the material of the substrate 100 is PI, and the material of the opposing substrate 400 is PET. The first embodiment does not have a flexible film, the material of the flexible film in the second embodiment is PET, and the material of the flexible film in the third and fourth embodiments is PDMS.

[0120] Furthermore, the pressure sensor of the third embodiment and the pressure sensor of the fourth embodiment have a flexible film made of the same material. However, the width of the cavity of the elastomer in the pressure sensor of the fourth embodiment is greater than the width of the cavity of the elastomer in the pressure sensor of the third embodiment. Figure 8 In the first to third embodiments, the width W1 of the cavity of the elastomer is (please refer to...) Figure 2 The width W1 of the cavity of the elastic body in the pressure sensor of the fourth embodiment is 500 micrometers.

[0121] Table 3 shows the voltage changes and pressure of the pressure sensors in the first to fourth embodiments.

[0122] Table 3

[0123]

[0124] Depend on Figure 8 As can be seen from Table 3, the voltage change measured by the pressure sensor in the second embodiment first decreases and then increases with increasing pressure. This is because the pressure sensor in the second embodiment uses PET as a flexible film, which is more prone to warping. In contrast, the third and fourth embodiments, which use PDMS as a flexible film, do not exhibit this voltage change pattern of first decreasing and then increasing.

[0125] In addition, based on Figure 8 As shown in Table 3, changing either the material of the flexible film or the width of the elastomer's cavity alters the relative relationship between the voltage change received by the pressure sensor and the applied pressure. In other words, the material of the flexible film or the width of the elastomer's cavity can be changed according to actual needs.

[0126] Figure 9 This is a circuit diagram of a pressure sensor according to an embodiment of the present invention. It must be noted that... Figure 9 The embodiments follow Figure 6 The component reference numerals and partial contents of the embodiments are described below, wherein the same or similar reference numerals are used to represent the same or similar components, and descriptions of the same technical content are omitted. For explanations of the omitted parts, please refer to the foregoing embodiments, and will not be repeated here.

[0127] Please refer to Figure 9 In this embodiment, each pressure sensing unit RU further includes a third switching element T3. First signal lines G1-2 to Gn-2 are electrically connected between the first resistor R1 and the fourth resistor R4 via the third switching element T3. The gates of the first switching element T1, the second switching element T2, and the third switching element T3 in a single pressure sensing unit RU are electrically connected to each other via corresponding gate signal lines G1-1 to Gn-1.

[0128] In this embodiment, multiple gate signal lines G1-1 to Gn-1 and multiple first signal lines G1-2 to Gn-2 are electrically connected to corresponding pressure sensing units RU. For example, the first row of pressure sensing units RU is electrically connected to the gate signal line G1-1 and the first signal line G1-2; the second row of pressure sensing units RU is electrically connected to the gate signal line G2-1 and the first signal line G2-2; and the nth row of pressure sensing units RU is electrically connected to the gate signal line Gn-1 and the first signal line Gn-2.

[0129] In this embodiment, the performance of the pressure sensor can be improved by setting the third switching element T3. Specifically, by setting the third switching element T3, when the third switching element T3 is not turned on, the current will not pass through the pressure sensing unit RU, thereby reducing the power consumption and heat generation of the pressure sensor and improving the safety of the pressure sensor when used in portable devices or medical devices.

[0130] Figure 10 This is a circuit diagram of a pressure sensor according to an embodiment of the present invention. It must be noted that... Figure 10 The embodiments follow Figure 9 The component reference numerals and partial contents of the embodiments are described below, wherein the same or similar reference numerals are used to represent the same or similar components, and descriptions of the same technical content are omitted. For explanations of the omitted parts, please refer to the foregoing embodiments, and will not be repeated here.

[0131] exist Figure 9 In one embodiment, each pressure sensing unit RU includes a third switching element T3, and each first signal line G1-2 to Gn-2 is electrically connected to a plurality of third switching elements T3. However, in Figure 10 In one embodiment, each of the first signal lines G1-2 to Gn-2 is electrically connected to multiple pressure sensing units RU through a third switching element T3.

[0132] Please refer to Figure 10 In the pressure sensing unit RU of the same column, the gate of the first switching element T1 and the gate of the second switching element T2 are electrically connected to a corresponding third switching element T3 through a corresponding gate signal line G1-1 to Gn-1.

[0133] In this embodiment, the performance of the pressure sensor can be improved by setting the third switching element T3. Specifically, by setting the third switching element T3, when the third switching element T3 is not turned on, the current will not pass through the pressure sensing unit RU, thereby reducing the power consumption and heat generation of the pressure sensor and improving the safety of the pressure sensor when used in portable devices or medical devices.

Claims

1. A pressure sensor, comprising: One substrate; Multiple pressure sensing units are located on the substrate, wherein each pressure sensing unit includes: A first resistor and a second resistor connected in series; A third resistor and a fourth resistor are connected in series, wherein the first resistor and the second resistor are connected in parallel to the third resistor and the fourth resistor; A first switching element is electrically connected between the first resistor and the second resistor; and A second switching element is electrically connected between the third resistor and the fourth resistor; A first signal line is electrically connected between the first resistor and the fourth resistor; A second signal line is electrically connected between the second resistor and the third resistor; An elastomer, situated on the substrate, includes a plurality of cavities, each cavity overlapping a corresponding pressure sensing unit, wherein the first resistor, the second resistor, the third resistor, and the fourth resistor at least partially overlap the cavity; and A pair of opposing substrates are located on the elastomer. The pressure sensor also includes: A flexible film, wherein the substrate is located between the pressure sensing unit and the flexible film, wherein the material of the flexible film is PU, PDMS or PET.

2. The pressure sensor of claim 1, wherein the first resistor, the second resistor, the third resistor, and the fourth resistor are made of polycrystalline silicon.

3. The pressure sensor as claimed in claim 1, wherein the hardness of the opposing substrate is greater than the hardness of the substrate, wherein when the material of the flexible film is PDMS, the thickness of the flexible film is 250 micrometers, 500 micrometers or 750 micrometers; wherein when the material of the flexible film is PET, the thickness of the flexible film is 20 micrometers or 40 micrometers.

4. The pressure sensor as claimed in claim 1, further comprising: A gate signal line is electrically connected to the gate of the first switching element and the gate of the second switching element; as well as A pad, wherein the elastomer and the opposing substrate expose the pad, wherein a flexible printed circuit board is electrically connected via the pad to a corresponding first switching element or the second switching element and a corresponding first resistor, the second resistor, the third resistor or the fourth resistor.

5. The pressure sensor as claimed in claim 1, further comprising: A third switching element, wherein the first signal line is electrically connected between the first resistor and the fourth resistor through the third switching element.

6. The pressure sensor of claim 5, wherein the gates of the first switching element, the second switching element, and the third switching element are electrically connected to each other.

7. The pressure sensor of claim 1, further comprising: A gate signal line is electrically connected to the gate of the first switching element and the gate of the second switching element in the pressure sensing units; A third switching element, wherein the first signal line is electrically connected to the pressure sensing units through the third switching element, and the gate of the third switching element is electrically connected to the gate signal line.

8. The pressure sensor of claim 1, wherein the sidewall of the cavity comprises a stepped, ramped, or vertical type, and the pressure sensor further comprises: Multiple conductive lines are formed on the substrate; A first insulating layer is located on the wires, wherein the pressure sensing units are located on the first insulating layer and electrically connected to the corresponding wires through a plurality of conductive holes in the first insulating layer; and A second insulating layer is located on the pressure sensing units and the first insulating layer, wherein the material of the first resistor, the second resistor, the third resistor and the fourth resistor of each pressure sensing unit includes metal oxide, and the second insulating layer includes hydrogen atoms.

9. The pressure sensor of claim 1, wherein the first resistor, the second resistor, the third resistor, and the fourth resistor partially overlap the edge of the cavity, the pressure sensor further comprising: A first insulating layer is located on the pressure sensing units; A second insulating layer is located on the pressure sensing units and the first insulating layer, wherein the second insulating layer has a plurality of grooves respectively overlapping the cavities, wherein each groove extends directly to the surface of the first resistor, the second resistor, the third resistor, or the fourth resistor; and Multiple wires are located on the second insulating layer, wherein each wire contacts the corresponding first resistor, second resistor, third resistor or fourth resistor through a corresponding groove.

10. The pressure sensor of claim 1, further comprising: A first signal sensing line is electrically connected to the first resistor and the second resistor through the first switching element; as well as A second signal sensing line is electrically connected to the third resistor and the fourth resistor via the second switching element.

11. The pressure sensor of claim 1, further comprising: Multiple first signal lines and multiple gate signal lines; as well as Multiple pressure sensing units are arranged in an array along a first direction and a second direction, wherein: The gates of the first switching elements and the gates of the second switching elements of the pressure sensing units arranged in the same column in the second direction are electrically connected to a corresponding gate signal line, and the pressure sensing units arranged in the same column in the second direction are electrically connected to a corresponding first signal line.

12. The pressure sensor of claim 1, further comprising: Multiple first signal sensing lines and multiple second signal sensing lines, wherein the first switching elements of the pressure sensing units arranged in the same row in a first direction are electrically connected to a corresponding first signal sensing line, and the second switching elements of the pressure sensing units arranged in the same row in the first direction are electrically connected to a corresponding second signal sensing line.

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