Pressure sensors and touch devices

Abstract

This disclosure provides a pressure sensor and a touch device. The pressure sensor includes a first substrate and a second substrate disposed opposite to each other, a thin-film transistor (TFT), and a plurality of protrusion structures. The TFT includes a gate, an active layer, and source / drain electrode layers. The source / drain electrode layers include a first electrode and a second electrode. The protrusion structures are located between the gate and the active layer and include a support portion and an elastic functional portion. Along the direction approaching the gate, the area of ​​the cross-section of the elastic functional portion parallel to the first substrate gradually increases. When the pressure sensor is not under pressure, the surface of the elastic functional portion near the first electrode has a first orthographic projection on the first substrate, and the surface of the elastic functional portion near the second electrode has a second orthographic projection on the first substrate. Both the first and second orthographic projections are located within the orthographic projection range of the source / drain electrode layers on the first substrate. When the pressure sensor is under pressure, the contact area between the active layer and the source / drain electrode layers increases to achieve pressure detection.

Description

Technical Field

[0001] This disclosure relates to the field of display technology, and more specifically to a pressure sensor and a touch device. Background Technology

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

[0003] This disclosure aims to address at least one of the technical problems existing in the prior art by proposing a pressure sensor and a touch device.

[0004] To achieve the above objectives, this disclosure provides a pressure sensor, comprising:

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

[0006] A thin-film transistor, comprising a gate, an active layer, and source / drain electrode layers, wherein the gate is located on the side of a first substrate closer to a second substrate, and the active layer is located on the side of the gate away from the first substrate; the source / drain electrode layers are located between the active layer and the second substrate; the source / drain electrode layers include a first electrode and a second electrode;

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

[0008] When the pressure sensor is not under pressure, the surface of the elastic functional part near the first pole has a first orthographic projection on the first substrate, and the surface of the elastic functional part near the second pole has a second orthographic projection on the first substrate. 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 apart from the edge of the orthographic projection of the source / drain electrode layer on the first substrate.

[0009] When the pressure sensor is not under pressure, the contact area between the active layer and the source / drain electrode layer is a first area; when the pressure sensor is under 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 close to the gate, the area of ​​the cross section 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 protrusion structures on the first substrate.

[0013] In some embodiments, the source and drain electrode layer includes a first electrode and a second electrode spaced apart, wherein the first electrode includes a first main body portion extending along a first direction and a plurality of first branch portions electrically connected to the first main body portion;

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

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

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

[0017] In some embodiments, the 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 onto the first substrate covers the orthographic projection of at least one of the elastic functional portions onto the first substrate.

[0018] In some embodiments, the pressure sensor further includes an insulating layer located between the protrusion 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 protrusion structure are an integral structure.

[0020] In some embodiments, the pressure sensor further includes an insulating layer located between the protrusion structure and the gate;

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

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

[0023] This disclosure also provides a touch device including a pressure sensor as described in any one of the above statements. Attached Figure Description

[0024] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0025] Figure 1 This is a cross-sectional structural diagram of the pressure sensor in an unpressurized state in some embodiments of this disclosure;

[0026] Figure 2 This is a cross-sectional structural diagram of the pressure sensor in an unpressurized state in some other embodiments of this disclosure;

[0027] Figure 3 This is a cross-sectional structural diagram of the pressure sensor in an unpressurized state in some embodiments of this disclosure;

[0028] Figure 4 This is a cross-sectional structural diagram of the pressure sensor in an unpressurized state in some embodiments of this disclosure;

[0029] Figure 5 This is a cross-sectional structural diagram of the pressure sensor in a non-pressurized state in some embodiments of this disclosure;

[0030] Figure 6 This is a cross-sectional structural diagram of the pressure sensor under pressure in some embodiments of this disclosure;

[0031] Figure 7 This is a cross-sectional structural diagram of the pressure sensor under pressure in some other embodiments of this disclosure;

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

[0033] Figure 9 Schematic diagram of the planar structure of the pressure sensor under pressure in other embodiments of this disclosure;

[0034] Figure 10 This is a schematic diagram of the planar structure of the pressure sensor in an unpressurized state in some embodiments of this disclosure. Detailed Implementation

[0035] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0036] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0037] Unless otherwise defined, the technical or scientific terms used in the embodiments of this disclosure should have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms "first," "second," and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only 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 situations that are similar to the described situation, within an acceptable range of deviation, which is determined by those skilled in the art taking into account the measurement under discussion and the error associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, “parallel” includes absolute parallelism and approximate parallelism, where an acceptable range of deviation for approximate parallelism may be, for example, within 5°; “perpendicular” includes absolute perpendicularity and approximate perpendicularity, where an acceptable range of deviation for approximate perpendicularity may also be, for example, within 5°.

[0039] It should be understood that when a layer or element is referred to as being on another layer or substrate, it can mean that the layer or element is directly on another layer or substrate, or that there is an intermediate layer between the layer or element and another layer or substrate.

[0040] This document describes exemplary embodiments with reference to sectional views and / or plan views, which are idealized exemplary drawings. In the drawings, the thickness of layers and regions is enlarged for clarity. Therefore, variations in shape relative to the drawings are contemplated due to, for example, manufacturing techniques and / or tolerances. Therefore, exemplary embodiments should not be construed as limited to the shapes of the regions shown herein, but rather include shape deviations due to, for example, manufacturing processes. Thus, the regions shown in the drawings are schematic in nature, and their shapes are not intended to show the actual shapes of the regions of the device, nor are they intended to limit the scope of the exemplary embodiments.

[0041] Pressure sensors are widely used in personal electronic devices and industrial monitoring, significantly contributing to the advancement of modern science and technology. Currently, transistor-based pressure sensors are widely employed. For example, organic field-effect transistors (OFETs) are used as active components in display panels and sensor devices within pressure sensors. However, pressure sensors lack sufficient pressure sensitivity under low pressure conditions and suffer from unsatisfactory response times. Furthermore, pressure sensors generally measure pressure based on changes in capacitance or resistance caused by pressure variations. They are often used in passive matrices employing multiple intersecting electrodes, where the disadvantages include difficulty in achieving independent control of each pixel unit and slow control speed for each row or column of pixels.

[0042] In order to at least alleviate or solve one of the aforementioned technical problems, this disclosure provides a pressure sensor and a touch device.

[0043] Figure 1 This is a cross-sectional structural diagram of the pressure sensor in an unpressurized state in some embodiments of this disclosure. Figure 2 This is a cross-sectional structural diagram of the pressure sensor in an unpressurized state in some other embodiments of this disclosure. Figure 3 This is a cross-sectional structural diagram of the pressure sensor in an unpressurized state in some embodiments of this disclosure. Figure 4 This is a cross-sectional structural diagram of the pressure sensor in an unpressurized state in some embodiments of this disclosure. Figure 5 This is a cross-sectional structural diagram of the pressure sensor in a non-pressurized state in some embodiments of this disclosure. Figure 6 This is a cross-sectional structural diagram of the pressure sensor under pressure in some embodiments of this disclosure. Figure 7This is a cross-sectional structural diagram of the pressure sensor under pressure in some other embodiments of this disclosure. Figure 8 This is a schematic diagram of the planar structure of the pressure sensor in some embodiments of this disclosure when it is not under pressure. Figure 9 Schematic diagrams of the planar structure of the pressure sensor under pressure in other embodiments of this disclosure. Figure 10 This is a schematic diagram of the planar structure of the pressure sensor in an unpressurized state in some embodiments of this disclosure.

[0044] In some embodiments, such as Figures 1 to 7 As shown, the pressure sensor disclosed herein includes: a first substrate 1 and a second substrate 2 disposed opposite to each other, a thin film transistor, and a plurality of protrusion structures 4.

[0045] The thin-film transistor includes a gate 3, an active layer 5, and source / drain electrode layers. The source / drain electrode layers include a first electrode 6 and a second electrode 7 spaced apart. The gate 3 is located on the side of the first substrate 1 closest to the second substrate 2, and the active layer 5 is located on the side of the protrusion structure 4 furthest from the first substrate 1. The source / drain electrode layers are 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 protrusion structure 4 is located between the gate 3 and the active layer 5, and the protrusion structure 4 is insulated from the gate 3. For example, a gate insulating layer 8 can be disposed between the protrusion structure 4 and the gate 3 to insulate the protrusion structure 4 from the gate 3. The protrusion structure 4 includes a support portion 42 near the gate 3 and an elastic functional portion 41 located on the side of the support portion 42 away from the gate 3. Along the direction near 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 the unpressurized state, the surface of the elastic functional part 41 near the first electrode 6 has a first orthographic projection 411 on the first substrate 1, and the surface of the elastic functional part 41 near the second electrode 7 has a second orthographic projection 412 on the first substrate 1. Both the first orthographic projection 411 and the second orthographic projection 412 are located within the orthographic projection range of the source / drain electrode layer on the first substrate 1, and are spaced apart from the edge of the orthographic projection of the source / drain electrode layer on the first substrate 1. Specifically, the orthographic projection of the first electrode 6 on the first substrate 1 covers and extends beyond the first orthographic projection 411, and / or, the orthographic projection of the second electrode 7 on the first substrate 1 covers and extends beyond the second orthographic projection 412. Furthermore, in the unpressurized state of the pressure sensor, the orthographic projection of the contact surface between the active layer 5 and the first electrode 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 electrode 7 on the first substrate 1 in the unpressurized state is a fourth orthographic projection 571. Therefore, when the pressure sensor is not under pressure, the contact area between the active layer 5 and the source / drain electrode layer is the first area, which 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 Figure 9 As shown, when the pressure sensor is under 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 under pressure, the contact area between the active layer 5 and the source / drain electrode layers is a second area, which 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 Figure 9 It can be seen that the second area is larger than the first area. Specifically, it can be understood that the orthographic projection of the first electrode 6 on the first substrate 1 covers and extends beyond the first orthographic projection 411, and the area of ​​the fifth orthographic projection 562 is larger than the area of ​​the third orthographic projection 561; and / or, the orthographic projection of the second electrode 7 on the first substrate 1 covers and extends beyond the second orthographic projection 412, and the area of ​​the sixth orthographic projection 572 is larger than the area of ​​the fourth orthographic projection 571.

[0050] In this embodiment, when the pressure sensor is under pressure, compared to when the pressure sensor is not under pressure, the contact area between the active layer 5 and the first electrode 6 increases, and / or the contact area between the active layer 5 and the second electrode 7 increases. Therefore, the contact resistance between the first electrode 6 and the second electrode 7 decreases, which is equivalent to an increase in the length (L) to width (W) ratio (W / L) of the thin-film transistor channel. According to the formula... It can be seen that the embodiments of this disclosure enable the drain current I... d It increases further, through the drain current I d The pressure is sensed and measured by observing changes in pressure; that is, by incorporating an elastic functional part 41 into the thin-film transistor, the thin-film transistor can be made to have pressure-sensitive performance. Wherein, V g V represents the gate voltage. th The threshold voltage is represented by μ, the electron migration rate is μ, and C is the capacitance value formed by the gate 3 and the source / drain electrode layers. The gate 3 and the source / drain electrode layers are equivalent to the two plates of a capacitor, and the gate insulating layer 8 and the active layer 5 between the gate 3 and the source / drain electrode layers are the dielectric materials between the two plates. The pressure sensor of this disclosure embodiment achieves pressure sensing performance directly by introducing an elastic functional part into a thin-film transistor. Therefore, the pressure sensor of this disclosure embodiment has a compact structure, simple manufacturing process, and strong practicality.

[0051] Furthermore, similarly, when the pressure on the pressure sensor changes, or when the pressure sensor is subjected to smaller and larger pressures 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 The pressure will also change; therefore, the pressure sensor in this embodiment can also measure pressure changes.

[0052] Optionally, the shape of the elastic functional part 41 can be a cone, an elliptical cone, a polygonal pyramid, a frustum, a truncated cone, or the like.

[0053] In this embodiment, by gradually increasing the area of ​​the cross-section of the elastic functional portion 41 parallel to the first substrate 1 along the direction close to the gate 3, pressure measurement can be achieved when the pressure sensor is subjected to pressure changes. Furthermore, the faster the area of ​​the cross-section of the elastic functional portion 41 parallel to the first substrate 1 changes, the higher the sensitivity of the pressure sensor.

[0054] Optionally, both the first substrate 1 and the second substrate 2 may include at least one of the following materials: flexible polyethylene (2,6-naphthalenedicarboxylate) (PEN), polyethylene (terephthalate) (PET), polyimide (PI), etc.

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

[0056] Optionally, the material of the gate insulating layer 8 can be a non-elastic material, such as at least one of SiNx, SiO2, Al2O3, etc.

[0057] Optionally, the active layer 5 may be made of a semiconductor. The semiconductor may be selected from at least one of organic semiconductors, oxide semiconductors, two-dimensional semiconductor materials, and carbon nanomaterials (such as graphene and CNTs).

[0058] Optionally, one of the first electrode 6 and the second electrode 7 is the drain electrode, and the other of the first electrode 6 and the second electrode 7 is the source electrode. Both the source electrode and the drain electrode can be selected from conductive materials such as metallic materials, carbon materials, and conductive polymers. Specifically, the metallic materials include at least one of Ag, Cu, Al, Cr, Mo, Au, Ti, and Pt. For example, the metallic materials include Cr / Au or Mo / Al / Mo. The carbon materials include at least one of carbon nanotubes (CNTs), half-wall carbon nanotubes (SWCNTs), and graphene. The conductive polymers include at least one of PEDOT:PSS, Ppy (polypyrrole), and PANI (polyaniline).

[0059] Optionally, the material of the elastic functional part 41 may be selected from an insulating polymer. For example, the material of the elastic functional part 41 may include at least one of the following: parylene (PET), polydimethylsiloxane (PDMS), polyurethane (PU), polyimide (PI), hydrogel, PMMA, etc.

[0060] In some embodiments, such as Figure 3 As shown, the support part 42 and the elastic functional part 41 are an integral structure.

[0061] In this embodiment, the support portion 42 and the elastic functional portion 41 are an integral structure, meaning that the support portion 42 and the elastic functional portion 41 are made of the same material. In this case, after forming an insulating elastomer 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 the protruding structure. Therefore, this embodiment simplifies the process. Furthermore, the support portion 42 in this embodiment is also elastic; therefore, the overall elasticity of the protruding structure 4 in this embodiment is increased, and thus, the pressure sensitivity performance of the pressure sensor can be correspondingly increased.

[0062] In some embodiments, such as Figure 3 As shown, the support portion 42 and the elastic functional portion 41 are an integral structure. Along the direction close to the gate 3, the area of ​​the cross section of the support portion 42 parallel to the first substrate 1 gradually increases; 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 protrusion structure 4 parallel to the first substrate 1 gradually increases. It is understood that, in the embodiments of this disclosure, the overall shape of the protrusion structure 4 can be a cone, an elliptical cone, a polygonal pyramid, a frustum, a truncated cone, etc.

[0064] The embodiments disclosed herein can ensure that even when the pressure sensor is subjected to large forces or deformations, 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 the drain current I. d The changes continue, namely ensuring that the pressure sensor can measure pressure, increasing the measurement range and sensitivity of the pressure sensor.

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

[0066] For example, in one example, such as Figure 5 and Figure 10 As shown, the active layer 5 includes a plurality of contact portions 51. Each contact portion 51 corresponds one-to-one with a protrusion structure 4. The orthographic projection of the contact portion 51 on the first substrate 1 covers and extends beyond the orthographic projection of the surface of the elastic functional portion 41 away from the gate 3 in the unpressed state on the first substrate 1. That is to say, in the embodiment of this disclosure, the orthographic projection of the contact portion 51 that contacts the first electrode 6 covers and extends beyond the first orthographic projection 411 on the first substrate 1, and the orthographic projection of the contact portion 51 that contacts the second electrode 7 covers and extends beyond the second orthographic projection 412 on the first substrate 1.

[0067] For example, in another example, such as 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. A protruding structure 4 is located in the central region A. An active layer 5 covers the central region A.

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

[0069] This embodiment of the present disclosure ensures that when the pressure sensor is subjected to pressure, i.e., when the elastic functional part 41 is compressed 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 the drain current I. This is achieved by having the active layer 5 cover and extend beyond the first orthographic projection 411 and the second orthographic projection 412. d The change ensures that the pressure sensor can measure pressure. Furthermore, making the active layer 5 a single, continuous film layer simplifies the process and reduces costs.

[0070] In some embodiments, such as Figure 8 As shown, the first pole 6 includes a first main body portion 61 extending along a first direction and a plurality of first branch portions 62 electrically connected to the first main body portion 61. The second pole 7 includes a second main body portion 71 extending along the first direction and a plurality of second branch portions 72 electrically connected to the second main body portion 71. The first main body portion 61 and the second main body portion 71 are arranged at intervals in a second direction, and the plurality of first branch portions 62 and the plurality of second branch portions 72 are all located between the first main body portion 61 and the second main body portion 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] This embodiment of the present disclosure, by positioning the first branch 62 and the second branch 72 between the first main body 61 and the second main body 71, and by arranging the first branch 62 and the second branch 72 alternately in a first direction, can further increase the aspect ratio W / L of the thin-film transistor channel, thereby increasing the drain current I. d This enables the pressure sensor to sense pressure. Therefore, the embodiments of this disclosure can further increase the sensitivity of the pressure sensor to pressure measurement based on the pressure measurement of the elastic functional part 41.

[0072] In some embodiments, such as Figure 8As shown, the orthographic projection of the first main body portion 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 portion 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 portion 61, the first branch portion 62, the second main body portion 71, and the second branch portion 72 each correspond to at least one protruding structure 4. Furthermore, the orthographic projections of the first main body portion 61, the first branch portion 62, the second main body portion 71, and the second branch portion 72 on the first substrate 1 cover their respective elastic functional portions 41. When the protruding structure 4 is an elastic body as a whole, the orthographic projections of the first main body portion 61, the first branch portion 62, the second main body portion 71, and the second branch portion 72 on the first substrate 1 cover their respective protruding structures 4.

[0073] This embodiment of the present disclosure, by setting the positional relationship between the first main body 61, the first branch 62, the second main body 71, the second branch 72 and the elastic functional part 41, can ensure that the first electrode 6 and the second electrode 7 can fully contact the active layer 5 when subjected to pressure, thereby measuring the pressure 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 protrusions 4 corresponding to the first main body portion 61 and the second main body portion 71 is the same. The number of protrusions 4 corresponding to each first branch portion 62 is the same. The number of protrusions 4 corresponding to each second branch portion 72 is the same. The number of protrusions 4 corresponding to the first branch portion 62 and the second branch portion 72 is the same.

[0075] Optionally, the protrusions 4 corresponding to the first main body portion 61 are evenly arranged. The protrusions 4 corresponding to the second main body portion 71 are evenly arranged. The protrusions 4 corresponding to the first branch portion 62 are evenly arranged. The protrusions 4 corresponding to the second branch portion 72 are evenly arranged.

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

[0077] The embodiments disclosed herein ensure that the uniform arrangement of the protruding structures guarantees effective measurement when pressure is applied to different locations of the pressure sensor or when the pressure at a certain location changes, thus ensuring the measurement effect and performance of the pressure sensor.

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

[0079] This embodiment of the invention makes the gate insulating layer 8 elastic. Under extreme pressure or when the elastic functional part 4 reaches its deformation limit, the gate insulating layer 8 deforms under stress, causing the distance between the gate 3 and the active layer 5 to decrease. This increases the capacitance C of the capacitor formed by the gate 3 and the source / drain electrode layers, further increasing the drain current I of the thin-film transistor. d The range of the pressure sensor is increased to allow for pressure measurement. Therefore, this embodiment of the present disclosure can increase the measurement range of the pressure sensor. At the same time, this embodiment of the present disclosure can also avoid problems such as damage to the pressure sensor caused by the protrusion structure 4 breaking under extreme pressure.

[0080] In some embodiments, such as 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 integral structures, and the gate insulating layer 8 and the protruding structure 4 are integral structures. 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] This embodiment of the invention can directly fabricate multiple protrusion structures 4 on the surface of an insulating elastomer formed of an elastic material, and the remaining portion of the insulating elastomer can then serve as a gate insulating layer 8. Therefore, this embodiment of the invention can save on processes and reduce costs.

[0082] In some embodiments, such as 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 this embodiment, the gate insulating layer 8 and the support portion 42 are integrally formed. Therefore, the micro-protrusion structure, i.e., the support portion 42, can be directly formed on the surface of an elastomer. Then, a corresponding elastic functional portion 41 can be formed on the side of each support portion 42 away from the first substrate 1. The pressure sensor structure of this embodiment is simple, which can reduce the difficulty of the manufacturing process and save costs.

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

[0085] In this embodiment, the elastic coefficient of the elastic functional part 41 is greater than or equal to the elastic coefficient of the gate insulating layer 8. This allows the elastic functional part 41 to deform preferentially over the gate insulating layer 8 when subjected to a small pressure, thereby sensing the pressure. Furthermore, in this embodiment, having a larger elastic coefficient in the elastic functional part 41 allows it to change 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 when subjected to a small pressure or a small change in the measured pressure, thereby improving the sensitivity of the pressure sensor.

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

[0087] The technical solutions and effects of this disclosure will be further described below with reference to specific embodiments.

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

[0089] In this case, the protrusion structure 4 can be fabricated by directly performing negative photolithography on the gate insulating layer 8 to form the elastic material PDMS. Specifically, the elastic material PDMS is formed on the side of the gate insulating layer 8 away from the first substrate 1, and a photoinitiator (e.g., 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 then...

[0090] The substrate is etched to obtain the raised structure 4. The etching process includes spin coating, pre-baking, UV exposure, development, rinsing, and post-baking. Those skilled in the art will understand that this etching process is similar to the organic film fabrication process of an array substrate or the PS (Photo Spacer) process for negative photoresist on a color filter substrate. Specific details will not be elaborated here.

[0091] like Figure 3As shown, when the pressure sensor is not subjected to external force, the contact areas between the active layer 5 and the first electrode 6, and between the active layer 5 and the second electrode 7, are relatively small due to the weight of the relevant parts of the pressure sensor itself (e.g., the second substrate 2, the first electrode 6, the second electrode 7, etc.) or the initial contact action. When the protrusion structure 4 is cone-shaped, the contact areas between the active layer 5 and the first electrode 6, and between the active layer 5 and the second electrode 7, are extremely small, and the contact surfaces between the active layer 5 and the first electrode 6, and between the active layer 5 and the second electrode 7, can both be point-like. In this case, even under relatively small pressure, the pressure sensor in this embodiment can sense the pressure; therefore, this embodiment has 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, as well as the contact area between the active layer 5 and the second electrode 7, both increase, resulting in an increase in the drain current I. d The size increases, thus enabling the pressure sensor to measure pressure.

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

[0094] The process of directly microstructuring the surface of an elastic material (e.g., PDMS) includes: preparing a microstructured pattern on a substrate mold, where the substrate mold can be a Si mold; coating the elastic material PMDS onto the Si mold; baking the elastic material PMDS to obtain pyramidal PDMS, the pyramidal PDMS having multiple pyramidal surfaces, the pyramids being the protrusions 4; and the untreated portion of the elastic material being the gate insulating layer 8. A gate Mo is formed on the side of the gate insulating layer 8 opposite to the protrusions 4 using photolithography and patterning. A flexible substrate PET is coated on the side of the gate 3 away from the protrusions 4 to form the first substrate 1, and then peeled off from the Si mold to obtain PET / Mo / pyramidal PDMS. CNTs are coated on the side of the pyramidal PDMS away from the first substrate 1 to form the active layer 5, and patterned using a laser. Finally, the pressure sensor is obtained by assembling it with a second substrate 2 having a first electrode 6 and a second electrode 7.

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

[0096] Phase 1: When a small pressure is applied in a direction perpendicular to the pressure sensor, each protrusion 4 deforms individually, increasing the contact area between the active layer 5 and the first electrode 6, as well as the contact area between the active layer 5 and the second electrode 7. This increases the drain current I of the thin-film transistor. d It gets bigger.

[0097] Second stage: When the protrusion structure 4 deforms to its maximum, if the pressure on the pressure sensor continues to increase, the thickness of the gate insulating layer 8 begins to be compressed. Specifically, as... Figure 4 As shown, when the pressure sensor is not under pressure, the gate insulating layer 8 is not compressed, and 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. At this time, the thickness of the gate insulating layer 8 is d2, which is obviously less than d1. Because the distance between the gate 3 and the active layer 5 decreases, the capacitance C between the gate 3 and the source / drain electrode layers increases. According to the drain current I... d The calculation formula shows that compressing the thickness of the gate insulating layer 8 can also increase the drain current I of the thin-film transistor. d The pressure increases. In this case, the pressure sensor will have a wider range of pressure sensing capabilities.

[0098] In summary, the pressure sensor based on a thin-film transistor provided in this disclosure can achieve pressure sensing by performing negative photolithography patterning on the surface of the gate insulating layer to form an elastic protrusion structure. The pressure sensor in the embodiments of this disclosure has a compact structure, simple manufacturing process, and strong practicality.

[0099] Compared to sensors based on pure composite materials, the pressure sensor in this embodiment of the present disclosure, by using an active matrix pressure sensor based on thin-film transistors, is able to have perfect signal transduction and amplification functions, thus having higher sensitivity and less inter-pixel crosstalk.

[0100] In some embodiments, this disclosure also provides a touch device including a pressure sensor as described in any embodiment of this disclosure.

[0101] The pressure sensor in this embodiment can be driven in an active matrix. Therefore, the touch device in this embodiment can drive an active matrix pressure sensor with a large area. The circuitry of the active matrix consists of scan lines and data lines, and the pressure sensor is designed to operate independently to provide a direct electrical response, depending on the selection of row and column combinations. This active matrix array is used to map the spatial distribution of various pressures applied to the sensing area.

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

[0103] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this 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, comprising a gate, an active layer, and source / drain electrode layers, wherein the gate is located on the side of a first substrate closer to a second substrate, and the active layer is located on the side of the gate away from the first substrate; the source / drain electrode layers are located between the active layer and the second substrate; the source / drain electrode layers include a first electrode and a second electrode; Multiple protruding structures; The protrusion structure is located between the gate and the active layer; the protrusion structure includes a support portion near the gate and an elastic functional portion located on the side of the support portion away from the gate; along the direction near the gate, the area of ​​the cross section of the elastic functional portion parallel to the first substrate gradually increases; When the pressure sensor is not under pressure, the surface of the elastic functional part near the first pole has a first orthographic projection on the first substrate, and the surface of the elastic functional part near the second pole has a second orthographic projection on the first substrate. 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 apart from the edge of the orthographic projection of the source / drain electrode layer on the first substrate. When the pressure sensor is not under pressure, the contact area between the active layer and the source / drain electrode layer is a first area; when the pressure sensor is under 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 support portion and the elastic functional portion are an integral structure.

3. The pressure sensor according to claim 2, characterized in that, Along the direction close to the gate, the area of ​​the cross section 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 onto the first substrate covers the orthographic projection of the surface of the elastic functional portion close to the gate onto 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 it covers the orthographic projections of the plurality of protrusion structures on the first substrate.

5. The pressure sensor according to any one of claims 1 to 3, characterized in that, The source and drain electrode layer includes a first electrode and a second electrode spaced apart. The first electrode includes a first main body portion extending along a first direction and a plurality of first branch portions electrically connected to the first main body portion. The second pole includes a second main body extending along a first direction and a plurality of second branches electrically connected to the second main body; The first main body and the second main body are arranged at intervals in the second direction, and the plurality of first branches and the plurality of second branches are all located between the first main body and the second main body, and the first branches and the second branches 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, The 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 onto the first substrate covers the orthographic projection of at least one of the elastic functional portions onto the first substrate.

7. The pressure sensor according to any one of claims 1 to 3, characterized in that, The pressure sensor also 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 supporting part and the elastic functional part are an integral structure; the insulating layer and the protruding structure are an integral structure.

9. The pressure sensor according to any one of claims 1 to 3, characterized in that, The pressure sensor also includes an insulating layer located between the protruding structure and the gate; The support 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 parylene, polydimethylsiloxane, polyurethane, polyimide, hydrogel, and polymethyl methacrylate.

11. A touch device, characterized in that, Includes the pressure sensor as described in any one of claims 1 to 10.

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