Pressure sensor and touch device

Abstract

The invention provides a pressure sensor and a touch device. The pressure sensor comprises a first substrate, a second substrate, a thin film transistor and a plurality of protrusion structures, wherein the first substrate and the second substrate are oppositely arranged. The thin film transistor includes a gate, an active layer, and a source-drain electrode layer. The source-drain electrode layer includes a first electrode and a second electrode. The protruding structure is located between the grid electrode and the active layer and comprises a supporting part and an elastic function part. Along the direction close to the grid electrode, the area of the cross section, parallel to the first substrate, of the elastic function part is gradually increased. When the pressure sensor is not subjected to pressure, the surface, close to the first pole, of the elastic function part has a first orthographic projection on the first substrate, and the surface, close to the second pole, of the elastic function part has a second orthographic projection on the first substrate. The first orthographic projection and the second orthographic projection are both located in the orthographic projection range of the source and drain electrode layer on the first substrate. When the pressure sensor is under pressure, the contact area of the active layer and the source and drain electrode layer is increased, so that pressure detection is realized.

Description

Technical Field

[0001] The present disclosure relates to the field of display technology, and in particular to a pressure sensor and a touch control device. Background Art

[0002] A pressure sensor is a device that can sense pressure signals and convert them into electrical signals. At present, various pressure sensors have been widely used in various electronic devices in production and life due to their advantages. For example, capacitive pressure sensors have the advantages of simple device design, convenient reading, good stability and low power consumption, while transistor-based sensors have the advantages of signal amplification, higher sensitivity and lower power consumption. Summary of the invention

[0003] The present disclosure aims to solve at least one of the technical problems existing in the prior art, and proposes a pressure sensor and a touch control device.

[0004] In order to achieve the above object, the present disclosure provides a pressure sensor, comprising:

[0005] A first substrate and a second substrate arranged opposite to each other;

[0006] A thin film transistor, the thin film transistor comprising a gate, an active layer and a source-drain electrode layer, the gate being located on a side of the first substrate close to the second substrate, the active layer being located on a side of the gate away from the first substrate; the source-drain electrode layer being located between the active layer and the second substrate; the source-drain electrode layer comprising a first pole and a second pole;

[0007] A plurality of protruding structures; the protruding structures are located between the gate and the active layer; the protruding structures include a supporting portion close to the gate and an elastic functional portion located on a side of the supporting portion away from the gate; along a direction close to the gate, an area of ​​a cross section of the elastic functional portion parallel to the first substrate gradually increases;

[0008] When the pressure sensor is not subjected to pressure, a surface of the elastic functional portion close to the first electrode has a first orthographic projection on the first substrate, and a surface of the elastic functional portion close to the second electrode has a second orthographic projection on the first substrate, and both the first orthographic projection and the second orthographic projection are located within the orthographic projection range of the source-drain electrode layer on the first substrate, and are spaced from an edge of the orthographic projection of the source-drain electrode layer on the first substrate;

[0009] When the pressure sensor is not subjected to pressure, the contact area between the active layer and the source-drain electrode layer is a first area; when the pressure sensor is subjected to pressure, the contact area between the active layer and the source-drain electrode layer is a second area, and the second area is larger than the first area.

[0010] In some embodiments, the support portion and the elastic functional portion are an integral structure.

[0011] In some embodiments, along the direction approaching the gate, the cross-sectional area of ​​the support portion parallel to the first substrate gradually increases; and the orthographic projection of the surface of the support portion away from the gate on the first substrate covers the orthographic projection of the surface of the elastic functional portion close to the gate on the first substrate.

[0012] In some embodiments, the orthographic projection of the active layer on the first substrate is a continuous pattern, and covers the orthographic projections of the plurality of protruding structures on the first substrate.

[0013] In some embodiments, the source-drain electrode layer includes a first electrode and a second electrode spaced apart from each other, the first electrode includes a first main body extending along a first direction and a plurality of first branches electrically connected to the first main body;

[0014] The second electrode includes a second main body extending along a first direction and a plurality of second branch parts electrically connected to the second main body;

[0015] The first main body portion and the second main body portion are arranged at intervals in the second direction, the plurality of first branch portions and the plurality of second branch portions are located between the first main body portion and the second main body portion, and the first branch portions and the second branch portions are arranged alternately in the first direction;

[0016] The first direction and the second direction intersect.

[0017] In some embodiments, an orthographic projection of any one of the first main body portion, the first branch portion, the second main body portion, and the second branch portion on the first substrate covers an orthographic projection of at least one of the elastic functional portions on the first substrate.

[0018] In some embodiments, the pressure sensor further includes an insulating layer located between the protruding structure and the gate; the insulating layer is elastic.

[0019] In some embodiments, the support portion and the elastic functional portion are an integral structure; the insulating layer and the protruding structure are an integral structure.

[0020] In some embodiments, the pressure sensor further comprises an insulating layer between the protruding structure and the gate;

[0021] The support portion and the insulating layer are an integral structure.

[0022] In some embodiments, the material of the elastic functional part includes at least one of polyparaxylene, polydimethylsiloxane, polyurethane, polyimide, hydrogel, and polymethyl methacrylate.

[0023] The present disclosure also provides a touch control device, comprising the pressure sensor as described in any one of the above. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0025] Figure 1 is a schematic diagram of a cross-sectional structure of a pressure sensor in some embodiments of the present disclosure when it is not under pressure;

[0026] Figure 2 is a schematic diagram of a cross-sectional structure of a pressure sensor in some other embodiments of the present disclosure when it is not under pressure;

[0027] Figure 3 is a schematic cross-sectional structure diagram of a pressure sensor in some embodiments of the present disclosure when it is not under pressure;

[0028] Figure 4 is a schematic cross-sectional structure diagram of a pressure sensor in some other embodiments of the present disclosure when it is not under pressure;

[0029] Figure 5 is a schematic cross-sectional structure diagram of a pressure sensor in some embodiments of the present disclosure in a non-pressure state;

[0030] Figure 6 is a schematic diagram of a cross-sectional structure of a pressure sensor in some embodiments of the present disclosure when under pressure;

[0031] Figure 7 is a schematic diagram of a cross-sectional structure of a pressure sensor in another embodiment of the present disclosure when under pressure;

[0032] Figure 8 is a schematic diagram of a planar structure of a pressure sensor in some embodiments of the present disclosure when it is not under pressure;

[0033] Fig. 9 A schematic diagram of a planar structure of a pressure sensor in some other embodiments of the present disclosure when it is under pressure;

[0034] Fig.10 It is a schematic diagram of the planar structure of the pressure sensor in some other embodiments of the present disclosure when it is not under pressure. DETAILED DESCRIPTION

[0035] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0036] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0037] Unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the present disclosure do not represent any order, quantity or importance, but are only used to distinguish different components. Similarly, "including" or "comprising" and similar words mean that the elements or objects appearing in front of the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0038] As used herein, "parallel" and "perpendicular" include the described situation and the situation similar to the described situation, and the range of the similar situation is within the acceptable deviation range, wherein the acceptable deviation range is determined by a person of ordinary skill in the art taking into account the measurement in question and the error associated with the measurement of a specific quantity (i.e., the limitations of the measurement system). For example, "parallel" includes absolute parallelism and approximate parallelism, wherein the acceptable deviation range of approximate parallelism can be, for example, a deviation within 5°; "perpendicular" includes absolute perpendicularity and approximate perpendicularity, wherein the acceptable deviation range of approximate perpendicularity can also be, for example, a deviation within 5°.

[0039] It will be understood that when a layer or an element is referred to as being on another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may be present between the layer or element and the other layer or substrate.

[0040] Exemplary embodiments are described herein with reference to cross-sectional views and / or plan views that are idealized exemplary drawings. In the drawings, the thickness of layers and regions are exaggerated for clarity. Therefore, variations in shape relative to the drawings due to, for example, manufacturing techniques and / or tolerances are conceivable. Therefore, the exemplary embodiments should not be interpreted as being limited to the shapes of the regions shown herein, but include deviations in shape due to, for example, manufacturing. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to illustrate the actual shapes of regions of the device, and are not intended to limit the scope of the exemplary embodiments.

[0041] Pressure sensors are widely used in personal electronic devices and industrial monitoring, and have greatly promoted the progress of science and technology in modern society. At present, transistor-based pressure sensors are widely used. For example, organic field-effect transistors (OFETs) have been used in pressure sensors as active components in display panels and sensor devices. However, pressure sensors do not have sufficient pressure sensitivity under low pressure conditions, and there are also problems such as unsatisfactory response time. In addition, the principle of pressure sensors is generally to measure pressure based on changes in capacitance or resistance caused by pressure changes. In addition, pressure sensors are mostly used in passive matrices that use multiple electrodes that cross each other. The disadvantage of passive matrices is that it is difficult to achieve independent control of each pixel unit and the control speed of each row or column of pixel units is slow.

[0042] In order to at least alleviate or solve one of the above-mentioned technical problems, the present disclosure provides a pressure sensor and a touch control device.

[0043] Figure 1 It is a schematic diagram of the cross-sectional structure of the pressure sensor in some embodiments of the present disclosure when it is not under pressure. Figure 2 It is a schematic diagram of the cross-sectional structure of the pressure sensor in some other embodiments of the present disclosure when it is not under pressure. Figure 3 2 is a schematic diagram of the cross-sectional structure of the pressure sensor in some other embodiments of the present disclosure when it is not under pressure. Figure 4 1 is a schematic diagram of the cross-sectional structure of the pressure sensor in some other embodiments of the present disclosure when it is not under pressure. Figure 5 FIG. 4 is a schematic diagram of the cross-sectional structure of the pressure sensor in some embodiments of the present disclosure in a non-pressure state. Figure 6 It is a schematic diagram of the cross-sectional structure of the pressure sensor in some embodiments of the present disclosure when under pressure. Figure 7It is a schematic diagram of the cross-sectional structure of the pressure sensor in other embodiments of the present disclosure when it is under pressure. Figure 8 It is a schematic diagram of the planar structure of the pressure sensor in some embodiments of the present disclosure when it is not under pressure. Fig. 9 Schematic diagram of the planar structure of the pressure sensor when under pressure in other embodiments of the present disclosure. Fig.10 It is a schematic diagram of the planar structure of the pressure sensor in some other embodiments of the present disclosure when it is not under pressure.

[0044] In some embodiments, Figures 1 to 7 As shown, the pressure sensor disclosed in the present invention includes: a first substrate 1 and a second substrate 2 that are arranged opposite to each other, a thin film transistor, and a plurality of protruding structures 4.

[0045] The thin film transistor includes a gate 3, an active layer 5 and a source-drain electrode layer. The source-drain electrode layer includes a first electrode 6 and a second electrode 7 arranged at intervals. The gate 3 is located on the side of the first substrate 1 close to the second substrate 2, and the active layer 5 is located on the side of the protrusion structure 4 away from the first substrate 1. The source-drain electrode layer is located between the active layer 5 and the second substrate 2. That is, the first electrode 6 and the second electrode 7 are located between the active layer 5 and the second substrate 2.

[0046] The protruding structure 4 is located between the gate 3 and the active layer 5, and the protruding structure 4 is insulated from the gate 3. For example, a gate insulating layer 8 may be provided between the protruding structure 4 and the gate 3 to insulate the protruding structure 4 from the gate 3. The protruding structure 4 includes a supporting portion 42 close to the gate 3 and an elastic functional portion 41 located on a side of the supporting portion 42 away from the gate 3. Along the direction close to the gate 3, the area of ​​the cross section of the elastic functional portion 41 parallel to the first substrate 1 gradually increases.

[0047] like Figures 1 to 5As shown, in a state where no pressure is applied, the surface of the elastic functional portion 41 close to the first pole 6 has a first orthographic projection 411 on the first substrate 1, and the surface of the elastic functional portion 41 close to the second pole 7 has a second orthographic projection 412 on the first substrate 1. The first orthographic projection 411 and the second orthographic projection 412 are both located within the orthographic projection range of the source-drain electrode layer on the first substrate 1, and are spaced from the orthographic projection edge of the source-drain electrode layer on the first substrate 1. Specifically, the orthographic projection of the first pole 6 on the first substrate 1 covers and exceeds the first orthographic projection 411, and / or, the orthographic projection of the second pole 7 on the first substrate 1 covers and exceeds the second orthographic projection 412. Furthermore, in a state where the pressure sensor is not subjected to pressure, the orthographic projection of the contact surface between the active layer 5 and the first pole 6 on the first substrate 1 is a third orthographic projection 561, and the orthographic projection of the contact surface between the active layer 5 and the second pole 7 on the first substrate 1 in a state where no pressure is applied is a fourth orthographic projection 571. Therefore, when the pressure sensor is not subjected to pressure, the contact area between the active layer 5 and the source-drain electrode layer is a first area, wherein the first area includes the area of ​​the third orthographic projection 561 and the area of ​​the fourth orthographic projection 571. The contact area refers to the area of ​​the contact surface.

[0048] Figure 6 , Figure 7 and Fig. 9 As shown, when the pressure sensor is subjected to pressure, the contact surface between the active layer 5 and the first electrode 6 has a fifth orthographic projection 562 on the first substrate 1, and the contact surface between the active layer 5 and the second electrode 7 has a sixth orthographic projection 572 on the first substrate 1. Therefore, when the pressure sensor is subjected to pressure, the contact area between the active layer 5 and the source-drain electrode layer is the second area, wherein the second area includes the area of ​​the fifth orthographic projection 562 and the area of ​​the sixth orthographic projection 572.

[0049] contrast Figure 3 and Figure 6 , Figure 4 and Figure 8 ,as well as Figure 8 and Fig. 9 It can be seen that the second area is greater than the first area. Specifically, it can be understood that the orthographic projection of the first pole 6 on the first substrate 1 covers and exceeds the first orthographic projection 411, and the area of ​​the fifth orthographic projection 562 is greater than the area of ​​the third orthographic projection 561; and / or, the orthographic projection of the second pole 7 on the first substrate 1 covers and exceeds the second orthographic projection 412, and the area of ​​the sixth orthographic projection 572 is greater than the area of ​​the fourth orthographic projection 571.

[0050] In the embodiment of the present disclosure, when the pressure sensor is under pressure, the contact area between the active layer 5 and the first electrode 6 is increased, and / or the contact area between the active layer 5 and the second electrode 7 is increased compared to the state where the pressure sensor is not under pressure. Therefore, the contact resistance between the first electrode 6 and the second electrode 7 is reduced, that is, the length (L) to width (W) ratio (W / L) of the channel equivalent to the thin film transistor is increased. According to the formula It can be seen that the embodiment of the present disclosure can make the drain current I d becomes larger, and further, through the drain current I d The pressure can be sensed and measured by the change of V, that is, the thin film transistor can be made sensitive to pressure by setting the elastic functional part 41 in the thin film transistor. g Represents the gate voltage, V th represents the threshold voltage, μ is the migration rate of electrons, and C is the capacitance value of the capacitor formed by the gate 3 and the source-drain electrode layer. Among them, the gate 3 and the source-drain electrode layer are equivalent to the two plates of the capacitor, and the gate insulating layer 8 and the active layer 5 between the gate 3 and the source-drain electrode layer are the dielectric materials between the two plates. The pressure sensor of the embodiment of the present disclosure can directly achieve the performance of sensing pressure by introducing an elastic functional part into a thin film transistor. Therefore, the pressure sensor of the embodiment of the present disclosure has a delicate structure, a simple process, and strong practicality.

[0051] Further, similarly, when the pressure on the pressure sensor changes, or when the pressure sensor is subjected to a smaller pressure and a larger pressure respectively, the area of ​​the fifth orthographic projection 562 and / or the area of ​​the sixth orthographic projection 572 will change. In this case, the drain current I d will also change, therefore, the pressure sensor in the embodiment of the present disclosure can also measure the change of pressure.

[0052] Optionally, the elastic functional portion 41 may be in the shape of a cone, an elliptical cone, a polygonal pyramid, a truncated cone, a truncated pyramid, or the like.

[0053] In the embodiment of the present disclosure, by gradually increasing the cross-sectional area of ​​the elastic functional portion 41 parallel to the first substrate 1 in the direction close to the gate 3, it is possible to measure the pressure when the pressure sensor is subjected to pressure changes. Furthermore, by making the cross-sectional area of ​​the elastic functional portion 41 parallel to the first substrate 1 change faster, the sensitivity of the pressure sensor is higher.

[0054] Optionally, the first substrate 1 and the second substrate 2 may both include at least one of flexible materials such as poly(ethylene 2,6-naphthalate) (PEN), poly(ethylene terephthalate) (PET), polyimide (PI), and the like.

[0055] Optionally, the material of the gate may include at least one of Ag, Cu, Al, Cr, Mo, Au, Ti, and Pt, for example, the material of the gate is Cr / Au or Mo / Al / Mo. Cr / Au represents a stacked Cr layer and an Au layer, and Mo / Al / Mo represents a sequentially stacked Mo layer, an Al layer, and a Mo layer.

[0056] Optionally, the material of the gate insulating layer 8 may be a non-elastic material, for example, the material of the gate insulating layer 8 may be at least one of SiNx, SiO2, Al2O3 and the like.

[0057] Optionally, the material of the active layer 5 includes a semiconductor, wherein the semiconductor may be selected from at least one of an organic semiconductor, an oxide semiconductor, a two-dimensional material semiconductor, a carbon nanomaterial (such as graphene, CNT), and the like.

[0058] Optionally, one of the first pole 6 and the second pole 7 is a drain, and the other of the first pole 6 and the second pole 7 is a source. Wherein, the source and the drain can be selected from conductive materials such as metal materials, carbon materials, and conductive polymers. Specifically, the metal material includes at least one of Ag, Cu, Al, Cr, Mo, Au, Ti, and Pt. For example, the metal material includes Cr / Au or Mo / Al / Mo. The carbon material includes at least one of carbon nanotubes (CNT), half-wall carbon nanotubes (SWCNT), graphene, etc. The conductive polymer includes at least one of PEDOT:PSS, Ppy (polypyrrole, polypyrrole), PANI (polyaniline), etc.

[0059] Optionally, the material of the elastic functional part 41 can be selected from insulating polymers. For example, the material of the elastic functional part 41 can include at least one of polyparaxylene (PET), polydimethylsiloxane (PDMS), polyurethane (PU), polyimide (PI), hydrogel, PMMA, etc.

[0060] In some embodiments, Figure 3 As shown, the support portion 42 and the elastic functional portion 41 are an integrated structure.

[0061] In the embodiment of the present disclosure, the support portion 42 and the elastic functional portion 41 are an integrated structure, that is, the support portion 42 and the elastic functional portion 41 are made of the same material. In this case, after the insulating elastomer is formed on the side of the gate insulating layer 8 away from the first substrate 1, the surface of the elastic insulator can be directly micro-processed to form microstructures such as cones to obtain a convex structure. Therefore, the embodiment of the present disclosure can simplify the process. In addition, the support portion 42 in the embodiment of the present disclosure is also elastic, so the overall elasticity of the convex structure 4 in the embodiment of the present disclosure is increased, and therefore, the pressure sensing performance of the pressure sensor can also be increased accordingly.

[0062] In some embodiments, Figure 3 As shown, the support portion 42 and the elastic functional portion 41 are an integral structure, and the area of ​​the cross section of the support portion 42 parallel to the first substrate 1 gradually increases along the direction approaching the gate 3; and the orthographic projection of the surface of the support portion 42 away from the gate 3 on the first substrate 1 covers the orthographic projection of the surface of the elastic functional portion 41 close to the gate 3 on the first substrate 1.

[0063] For example, in one example, the area of ​​the cross section of the entire protrusion structure 4 parallel to the first substrate 1 gradually increases. It is understandable that in the embodiment of the present disclosure, the shape of the entire protrusion structure 4 can be a cone, an elliptical cone, a polygonal pyramid, a truncated cone, a prism, etc.

[0064] The embodiment of the present disclosure can ensure that when the pressure sensor is subjected to a large force or has a large deformation, the contact area between the first electrode 6 and the active layer 5 and / or the contact area between the second electrode 7 and the active layer 5 can still be increased, thereby ensuring that the drain current I d Continue to change, that is, to ensure that the pressure sensor can measure pressure and increase the measurement range and sensitivity of the pressure sensor.

[0065] In some embodiments, Figure 8 and Fig. 9 As shown, the active layer 5 covers and exceeds the first orthographic projection 411 and / or the second orthographic projection 412 .

[0066] For example, in one example, Figure 5 and Fig.10 As shown, the active layer 5 includes a plurality of contact portions 51. The contact portions 51 correspond one to one with the protruding structures 4. The orthographic projection of the contact portion 51 on the first substrate 1 covers and exceeds the orthographic projection of the surface of the elastic functional portion 41 away from the gate 3 in the unstressed state on the first substrate 1. That is, it can be understood that, in the embodiment of the present disclosure, the orthographic projection of the contact portion 51 in contact with the first pole 6 on the first substrate 1 covers and exceeds the first orthographic projection 411, and the orthographic projection of the contact portion 51 in contact with the second pole 7 on the first substrate 1 covers and exceeds the second orthographic projection 412.

[0067] For example, in another example, Figure 3 and Figure 8 As shown, the pressure sensor has a central region A and an edge region B surrounding the central region A. The protrusion structure 4 is located in the central region A. The active layer 5 covers the central region A.

[0068] In some embodiments, Figure 3 and Figure 8 As shown, the orthographic projection of the active layer 5 on the first substrate 1 is a continuous pattern, and covers the orthographic projections of the plurality of protrusion structures 4 on the first substrate 1. That is, it can be understood that the active layer 5 is a complete continuous film layer.

[0069] In the embodiment of the present disclosure, the active layer 5 covers and exceeds the first orthographic projection 411 and the second orthographic projection 412, so as to ensure that when the pressure sensor is subjected to pressure, that is, when the elastic functional part 41 is squeezed and deformed, the contact area between the first electrode 6 and the active layer 5 and / or the contact area between the second electrode 7 and the active layer 5 changes, thereby ensuring that the drain current I d In addition, making the active layer 5 a complete continuous film layer is beneficial to simplifying the process and reducing the cost.

[0070] In some embodiments, Figure 8 As shown, the first pole 6 includes a first main body 61 extending along the first direction and a plurality of first branch portions 62 electrically connected to the first main body 61. The second pole 7 includes a second main body 71 extending along the first direction and a plurality of second branch portions 72 electrically connected to the second main body 71. The first main body 61 and the second main body 71 are arranged at intervals in the second direction, and the plurality of first branch portions 62 and the plurality of second branch portions 72 are both located between the first main body 61 and the second main body 71, and the first branch portions 62 and the second branch portions 72 are arranged alternately in the first direction. The first direction and the second direction intersect. Optionally, the first direction and the second direction are perpendicular.

[0071] In the embodiment of the present disclosure, the first branch portion 62 and the second branch portion 72 are located between the first main portion 61 and the second main portion 71, and the first branch portion 62 and the second branch portion 72 are alternately arranged in the first direction, so as to further increase the aspect ratio W / L of the channel of the thin film transistor, thereby increasing the drain current I d , so that the pressure sensor can sense pressure. Therefore, the embodiment of the present disclosure can further increase the sensitivity of the pressure sensor to pressure measurement based on the elastic functional part 41 measuring pressure.

[0072] In some embodiments, Figure 8As shown, the orthographic projection of the first main body 61 on the first substrate 1 covers the orthographic projection of at least one protruding structure 4 on the first substrate 1. The orthographic projection of the first branch portion 62 on the first substrate 1 covers the orthographic projection of at least one elastic functional portion 41 on the first substrate 1. The orthographic projection of the second main body 71 on the first substrate 1 covers the orthographic projection of at least one elastic functional portion 41 on the first substrate 1. The orthographic projection of the second branch portion 72 on the first substrate 1 covers the orthographic projection of at least one elastic functional portion 41 on the first substrate 1. It can also be understood that the first main body 61, the first branch portion 62, the second main body 71 and the second branch portion 72 correspond to at least one protruding structure 4 respectively. Moreover, the orthographic projections of the first main body 61, the first branch portion 62, the second main body 71 and the second branch portion 72 on the first substrate 1 cover the corresponding elastic functional portions 41. When the protruding structure 4 is an elastic body as a whole, the orthographic projections of the first main body 61, the first branch portion 62, the second main body 71 and the second branch portion 72 on the first substrate 1 cover the corresponding protruding structures 4.

[0073] The disclosed embodiment ensures that the first pole 6 and the second pole 7 can fully contact the active layer 5 when under pressure by setting the positional relationship between the first main body 61, the first branch portion 62, the second main body 71 and the second branch portion 72 and the elastic functional portion 41, so that the pressure can be measured by the change in the contact area between each part and the active layer 5 when the pressure changes, thereby improving the sensitivity of the pressure sensor.

[0074] Optionally, the number of protruding structures 4 corresponding to the first main body 61 and the second main body 71 is the same. The number of protruding structures 4 corresponding to each first branch 62 is the same. The number of protruding structures 4 corresponding to each second branch 72 is the same. The number of protruding structures 4 corresponding to the first branch 62 and the second branch 72 is the same.

[0075] Further optionally, the protruding structures 4 corresponding to the first main body 61 are arranged evenly. The protruding structures 4 corresponding to the second main body 71 are arranged evenly. The protruding structures 4 corresponding to the first branch portions 62 are arranged evenly. The protruding structures 4 corresponding to the second branch portions 72 are arranged evenly.

[0076] Optionally, all the protruding structures 4 are arranged uniformly or periodically according to a rule.

[0077] The embodiment of the present disclosure arranges the protruding structures uniformly to ensure that when different positions of the pressure sensor are subjected to pressure or when the pressure at a certain position changes, effective measurement can be performed, thereby ensuring the measurement effect and performance of the pressure sensor.

[0078] In some embodiments, Figures 3 to 5As shown, the pressure sensor further includes a gate insulating layer 8 located between the protruding structure 4 and the gate 3. The gate insulating layer 8 is elastic.

[0079] In the embodiment of the present disclosure, the gate insulating layer 8 is also elastic. When subjected to great pressure or when the elastic functional portion 4 is deformed to the limit, the gate insulating layer 8 is deformed by force so that the distance between the gate 3 and the active layer 5 is reduced, thereby increasing the capacitance C of the capacitor formed by the gate 3 and the source-drain electrode layer, so as to further increase the drain electrode current I of the thin film transistor. d The pressure is increased to measure the pressure. Therefore, the embodiment of the present disclosure can increase the measuring range of the pressure sensor. At the same time, the embodiment of the present disclosure can also avoid the problem of the protrusion structure 4 being damaged when subjected to extremely high pressure, which may cause damage to the pressure sensor.

[0080] In some embodiments, Figure 4 and Figure 5 As shown, the gate insulating layer 8 is elastic. The support portion 42 and the elastic functional portion 41 are an integral structure, and the gate insulating layer 8 and the protruding structure 4 are an integral structure. That is, the support portion 42 and the gate insulating layer 8 are made of the same material as the elastic functional portion 41.

[0081] The embodiment of the present disclosure can directly prepare a plurality of protruding structures 4 on the surface of the insulating elastic body formed of elastic material, and the remaining part of the insulating elastic body can serve as the gate insulating layer 8. Therefore, the embodiment of the present disclosure can save process and cost.

[0082] In some embodiments, Figure 2 As shown, the gate insulating layer 8 and the support portion 42 are an integral structure, that is, the support portion 42 and the gate insulating layer 8 are made of the same material.

[0083] In the embodiment of the present disclosure, the gate insulating layer 8 and the support portion 42 are an integral structure, so a micro-convex structure, namely the support portion 42, can be directly formed on the surface of an elastic body. Then, a corresponding elastic functional portion 41 can be further formed on the side of each support portion 42 away from the first substrate 1. The pressure sensor of the embodiment of the present disclosure has a simple structure, which can reduce the difficulty of the preparation process and save costs.

[0084] In some embodiments, the elastic coefficient of the elastic function portion 41 is greater than or equal to the elastic coefficient of the gate insulating layer 8 .

[0085] In the embodiment of the present disclosure, the elastic coefficient of the elastic functional portion 41 is made greater than or equal to the elastic coefficient of the gate insulating layer 8, so that when subjected to a small pressure, the elastic functional portion 41 is deformed before the gate insulating layer 8, thereby sensing the pressure. Further, in the embodiment of the present disclosure, the elastic functional portion 41 is made to have a large elastic coefficient, so that when subjected to a small pressure or a small change in the measured pressure, the elastic functional portion 41 can change the contact area between the first pole 6 and the active layer 5 and / or the contact area between the second pole 7 and the active layer 5, thereby improving the sensitivity of the pressure sensor.

[0086] In all embodiments of the present disclosure, the gate insulating layer 8 can be either elastic or inelastic, and the choice can be made according to actual needs.

[0087] The technical scheme and technical effects of the present disclosure are further described below in conjunction with specific embodiments.

[0088] In some embodiments, Figure 3 As shown, the first substrate 1 and the second substrate 2 are both flexible substrates, and the materials include PET. The gate material includes Mo / Al / Mo. The gate insulating layer 8 is a non-elastic body, and the material is SiO2. The material of the active layer 5 includes an organic semiconductor PCDTPT; the materials of the first pole 6 and the second pole 7 both include Al. The support portion 42 and the elastic functional portion 41 in the protruding structure 4 are an integrated structure, that is, the protruding structure 4 is an elastomer as a whole, and the material is PDMS.

[0089] In this case, the protrusion structure 4 can be prepared by directly performing negative photolithography on the elastic material PDMS on the gate insulating layer 8. Specifically, the elastic material PDMS is formed on the side of the gate insulating layer 8 away from the first substrate 1, a photoinitiator (such as benzophenone or 2,2-dimethoxy-2-phenylacetophenone, DMAP) is added to the elastic material PDMS to obtain a PDMS matrix with negative photoresist properties, and the PDMS is photolithographically processed.

[0090] The substrate is subjected to an etching process to obtain a protruding structure 4. The specific steps of the etching process include: spin coating, pre-baking, UV exposure, development, rinsing and post-baking. It can be understood by those skilled in the art that this etching process is similar to the organic film preparation process of the array substrate or the PS (Photo Spacer) process of the negative photoresist of the color film substrate. The specific process will not be repeated here.

[0091] like Figure 3As shown, when the pressure sensor is not subjected to external force, under the self-weight or initial contact of the relevant parts of the pressure sensor itself (for example, the second substrate 2, the first pole 6, the second pole 7, etc.), the contact area between the active layer 5 and the first pole 6 and the contact area between the active layer 5 and the second pole 7 are relatively small. In the case where the protruding structure 4 is in a cone shape, the contact area between the active layer 5 and the first pole 6 and the contact area between the active layer 5 and the second pole 7 are very small, and the contact surface between the active layer 5 and the first pole 6 and the contact surface between the active layer 5 and the second pole 7 can be in a point shape. At this time, even when subjected to a small pressure, the pressure sensor in the embodiment of the present disclosure can sense the pressure, so the embodiment of the present disclosure has a high sensitivity.

[0092] like Figure 6 As shown, when the pressure sensor is subjected to an external force F, the contact area between the active layer 5 and the first electrode 6 and the contact area between the active layer 5 and the second electrode 7 are increased, so that the drain current I d becomes larger, thereby enabling the pressure sensor to measure pressure.

[0093] In other embodiments, Figure 4 As shown, the gate insulating layer 8 is elastic and is an integral structure with the protruding structure 4, wherein the protruding structure 4 is also an elastic body as a whole. Figure 4 The gate insulating layer 8 and the protruding structure 4 in the embodiment shown can be formed by directly microstructuring the surface of an elastic material (such as PDMS). The first substrate 1 and the second substrate 2 are both flexible substrates, and the materials are both PET. The material of the gate includes Mo, and the material of the active layer 5 includes CNT.

[0094] The process of directly microstructuring the surface of an elastic material (such as PDMS) includes: preparing a surface microstructuring pattern on a substrate mold, wherein the substrate mold can be a Si mold. The elastic material PMDS is coated on the Si mold, and the elastic material PMDS is baked to obtain a pyramidal PDMS, wherein the pyramidal PDMS has a surface with multiple pyramids, and the pyramids are the protruding structures 4, and the untreated part of the elastic material is the gate insulating layer 8. On the side of the gate insulating layer 8 facing away from the protruding structure 4, a gate Mo is formed by photolithography definition, patterning, etc. A flexible substrate PET is coated on the side of the gate 3 away from the protruding structure 4 to form a first substrate 1, and it is peeled off from the Si mold to obtain PET / Mo / pyramid PDMS. CNT is coated on the side of the pyramidal PDMS away from the first substrate 1 to form an active layer 5, and patterning is performed using a laser. Finally, a pressure sensor can be obtained by aligning the second substrate 2 provided with a first pole 6 and a second pole 7.

[0095] In the embodiment of the present disclosure, the operating mechanism of the pressure sensor under external force has two stages:

[0096] Phase 1: When a small pressure acts in a direction perpendicular to the pressure sensor, each protrusion structure 4 deforms individually, thereby increasing the contact area between the active layer 5 and the first electrode 6, and the contact area between the active layer 5 and the second electrode 7, so that the drain electrode current I d Get bigger.

[0097] The second stage: when the protrusion structure 4 is deformed to the maximum, if the pressure on the pressure sensor continues to increase, the thickness of the gate insulation layer 8 begins to be compressed. Figure 4 As shown in FIG. 1 , when the pressure sensor is not subjected to pressure, the gate insulating layer 8 is not compressed. At this time, the thickness of the gate insulating layer 8 is d1. Figure 7 As shown, when the sensor is subjected to pressure F, the gate insulating layer 8 is compressed, and the thickness of the gate insulating layer 8 is d2. Obviously, d2 is smaller than d1. As the distance between the gate 3 and the active layer 5 decreases, the capacitance C between the gate 3 and the source-drain electrode layer increases. According to the drain electrode current I d The calculation formula shows that the thickness of the gate insulating layer 8 is compressed, which can also make the drain current I of the thin film transistor d In this case, the sensing pressure range of the pressure sensor will be larger.

[0098] In summary, the pressure sensor based on thin film transistor provided by the present disclosure can perform negative photolithography patterning on the surface of the gate insulating layer to form an elastic protrusion structure, thereby realizing pressure sensing. The pressure sensor in the embodiment of the present disclosure has a delicate structure, simple process and strong practicality.

[0099] Compared with sensors based on pure composite materials, the pressure sensor in the embodiment of the present disclosure can have perfect functions of signal transduction and amplification by using an active matrix pressure sensor based on thin film transistors, and thus has higher sensitivity and less crosstalk between pixels.

[0100] In some embodiments, the present disclosure further provides a touch control device, which includes a pressure sensor as described in any embodiment of the present disclosure.

[0101] The pressure sensor in the embodiment of the present disclosure can be driven in an active matrix. Therefore, the touch device in the embodiment of the present disclosure can drive an active matrix pressure sensor with a large area. Among them, the circuit of the active matrix is ​​composed of scan lines and data lines, and the pressure sensor is designed to operate alone to give a direct electrical response according to the selection of row and column combinations. The active matrix array is used to map the spatial distribution of various pressures applied to the sensing area.

[0102] The touch device in the embodiment of the present disclosure may be, for example, a fingerprint unlocking device, a pulse detection device, etc.

[0103] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present disclosure, but the present disclosure is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and substance of the present disclosure, and these modifications and improvements are also considered to be within the scope of protection of the present disclosure.

Claims

1. A pressure sensor, characterized in that: include: A first substrate and a second substrate arranged opposite to each other; A thin film transistor, the thin film transistor comprising a gate, an active layer and a source-drain electrode layer, the gate being located on a side of the first substrate close to the second substrate, the active layer being located on a side of the gate away from the first substrate; the source-drain electrode layer being located between the active layer and the second substrate; the source-drain electrode layer comprising a first pole and a second pole; multiple raised structures; The protruding structure is located between the gate and the active layer; the protruding structure comprises a supporting portion close to the gate and an elastic functional portion located on a side of the supporting portion away from the gate; along a direction close to the gate, an area of ​​a cross section of the elastic functional portion parallel to the first substrate gradually increases; When the pressure sensor is not subjected to pressure, a surface of the elastic functional portion close to the first electrode has a first orthographic projection on the first substrate, and a surface of the elastic functional portion close to the second electrode has a second orthographic projection on the first substrate, and both the first orthographic projection and the second orthographic projection are located within the orthographic projection range of the source-drain electrode layer on the first substrate, and are spaced from an edge of the orthographic projection of the source-drain electrode layer on the first substrate; When the pressure sensor is not subjected to pressure, the contact area between the active layer and the source-drain electrode layer is a first area; when the pressure sensor is subjected to pressure, the contact area between the active layer and the source-drain electrode layer is a second area, and the second area is larger than the first area.

2. The pressure sensor according to claim 1, characterized in that: The supporting part and the elastic functional part are an integrated structure.

3. The pressure sensor according to claim 2, characterized in that: Along the direction approaching the gate, the cross-sectional area of ​​the support portion parallel to the first substrate gradually increases; and the orthographic projection of the surface of the support portion away from the gate on the first substrate covers the orthographic projection of the surface of the elastic functional portion close to the gate on the first substrate.

4. The pressure sensor according to any one of claims 1 to 3, characterized in that: The orthographic projection of the active layer on the first substrate is a continuous pattern, and covers the orthographic projections of the plurality of protruding structures on the first substrate.

5. The pressure sensor according to any one of claims 1 to 3, characterized in that: The source-drain electrode layer includes a first electrode and a second electrode arranged at intervals, wherein the first electrode includes a first main body extending along a first direction and a plurality of first branch parts electrically connected to the first main body; The second electrode includes a second main body extending along a first direction and a plurality of second branch parts electrically connected to the second main body; The first main body portion and the second main body portion are arranged at intervals in the second direction, the plurality of first branch portions and the plurality of second branch portions are located between the first main body portion and the second main body portion, and the first branch portions and the second branch portions are arranged alternately in the first direction; The first direction and the second direction intersect.

6. The pressure sensor according to claim 5, characterized in that: An orthographic projection of any one of the first main body portion, the first branch portion, the second main body portion, and the second branch portion on the first substrate covers an orthographic projection of at least one of the elastic functional portions on the first substrate.

7. The pressure sensor according to any one of claims 1 to 3, characterized in that: The pressure sensor further includes an insulating layer located between the protruding structure and the gate; the insulating layer is elastic.

8. The pressure sensor according to claim 7, characterized in that: The support portion and the elastic functional portion are an integrated structure; the insulating layer and the protruding structure are an integrated structure.

9. The pressure sensor according to any one of claims 1 to 3, characterized in that: The pressure sensor further includes an insulating layer located between the protrusion structure and the gate; The support portion and the insulating layer are an integral structure.

10. The pressure sensor according to any one of claims 1 to 3, characterized in that: The material of the elastic functional part includes at least one of polyparaxylene, polydimethylsiloxane, polyurethane, polyimide, hydrogel, and polymethyl methacrylate.

11. A touch device, characterized in that: Comprising the pressure sensor according to any one of claims 1 to 10.

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