Thin film sensor and preparation method thereof

Abstract

The present disclosure provides a thin film sensor and a method for preparing the same, belonging to the field of sensor technology. The thin film sensor of the present invention has a plurality of cross-arranged conductive lines in the region, and a plurality of hollow portions defined by the cross-arrangement of the plurality of conductive lines in the region; the thin film sensor comprises: a base substrate, a plurality of conductive lines arranged on the base substrate, with one conductive line arranged in each region where the conductive lines are located; a functional structure arranged on the base substrate; wherein the functional structure is configured to emit at least a portion of light transmitted along a preset direction and incident on the functional structure from the region where the conductive lines are located, through the hollow portion; wherein the preset direction is the direction from the base substrate toward the conductive lines.

Description

Technical Field

[0001] The present invention belongs to the technical field of sensors, and in particular relates to a thin film sensor and a preparation method thereof. Background Art

[0002] With the development of IoT and communications technologies, demand for thin-film sensors, such as thin-film antennas, is increasing. Transparent antennas are gaining popularity for better integration into everyday life. For example, transparent antennas can be integrated with architectural glass, rail transit glass, and automotive glass. Not only do they maintain visibility, they also facilitate information transmission, enabling the interconnection of everything and making life more convenient. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art and provides a thin film sensor and a preparation method thereof.

[0004] In a first aspect, an embodiment of the present disclosure provides a thin film sensor, comprising:

[0005] substrate,

[0006] A plurality of conductive lines are arranged on the base substrate, and the plurality of conductive lines are cross-arranged to define a plurality of hollow portions;

[0007] A functional structure is arranged on the base substrate; wherein the functional structure is configured to emit at least part of the light transmitted along a preset direction and incident on the functional structure from the area where the conductive line is located through the hollow portion; wherein the preset direction is the direction in which the base substrate points to the conductive line.

[0008] Wherein, the thin film sensor further comprises a planarization layer covering a side of the plurality of conductive lines facing away from the substrate;

[0009] The functional structure includes: a first dielectric layer provided on a side of the conductive line close to the substrate; and the refractive index of the first dielectric layer is smaller than the refractive index of the planarization layer;

[0010] The first dielectric layer includes a plurality of first main body portions arranged crosswise; one of the first main body portions overlaps with an orthographic projection of one of the conductive lines on the substrate base.

[0011] Wherein, the functional structure comprises: a first dielectric layer and a second dielectric layer provided on the substrate; the refractive index of the first dielectric layer is smaller than the refractive index of the second dielectric layer;

[0012] The first dielectric layer is arranged on a side of the conductive line close to the substrate; the first dielectric layer includes a plurality of first main bodies arranged crosswise; one of the first main bodies overlaps with an orthographic projection of one of the conductive lines on the substrate;

[0013] The second dielectric layer includes a plurality of first grooves arranged crosswise; one first main body is filled in one of the first grooves.

[0014] Wherein, the functional structure further includes a first flat portion; the first flat portion is located between the conductive wire and the second dielectric layer, and is connected to the plurality of first main body portions to form an integrated structure.

[0015] The thin film sensor further includes a planarization layer covering a side of the plurality of conductive lines facing away from the base substrate; and a difference in refractive index between the planarization layer and the second dielectric layer is no greater than 0.2.

[0016] Wherein, the thickness of the first main body portion is at least 1.5 times its maximum width.

[0017] Wherein, micro-nano scattering particles or micro-nano scattering voids are doped in the first main body.

[0018] In which, the first main body has a first cross-section perpendicular to its extension direction; the first cross-section has at least one side edge away from the top edge of the base substrate and connected to the top edge; the angle between the tangent line at any point on the side edge and the top edge of the base substrate is not greater than 90°.

[0019] The shape of the first cross section includes any one of an inverted trapezoid, an inverted triangle, and a semi-ellipse.

[0020] Wherein, the functional structure includes a third dielectric layer; the third dielectric layer is provided on the base substrate, and a fourth dielectric layer is provided between the third dielectric layer and the layer where the conductive line is located;

[0021] The third dielectric layer includes a plurality of second main body portions arranged crosswise; one of the second main body portions overlaps with an orthographic projection of one of the conductive lines on the base substrate.

[0022] The second main body portion includes any one of a metal film, a semi-reflective semi-transparent film, and a distributed Rager reflector.

[0023] The thin film sensor further includes a planarization layer covering a side of the plurality of conductive lines facing away from the base substrate; and a difference in refractive index between the planarization layer and the fourth dielectric layer is not greater than 0.05.

[0024] Wherein, a reflective sheet is provided on the side of the conductive line opposite to the second main body portion.

[0025] In a second aspect, the present disclosure provides a method for preparing a thin film sensor, which comprises:

[0026] A plurality of cross-arranged conductive lines and functional structures are formed on a base substrate; wherein the functional structure is configured to emit at least a portion of light transmitted along a preset direction and incident on the functional structure from the area where the conductive lines are located out through the hollow portion; wherein the preset direction is the direction from the base substrate to the conductive lines.

[0027] Wherein, the functional structure includes a first dielectric layer provided on a base substrate;

[0028] The step of forming the first dielectric layer includes:

[0029] On a side of the conductive line close to the substrate, a plurality of first main body portions are formed that are cross-arranged, and one of the first main body portions overlaps with an orthographic projection of a conductive line to be formed on the substrate;

[0030] The preparation method further comprises:

[0031] A pattern including a planarization layer is formed on a side of the first dielectric layer facing away from the base substrate; and a refractive index of the first dielectric layer is smaller than a refractive index of the planarization layer.

[0032] The functional structure includes: a first dielectric layer and a second dielectric layer provided on the substrate; the refractive index of the first dielectric layer is less than the refractive index of the second dielectric layer; and the steps of forming the functional structure include:

[0033] A second dielectric layer is formed on a side of the conductive line close to the base substrate, and a plurality of first grooves are formed on the second dielectric layer;

[0034] A first dielectric layer is formed between the second dielectric layer and the conductive line. The first dielectric layer includes a plurality of first main body portions arranged crosswise. One of the first main body portions overlaps with an orthographic projection of one of the conductive lines on the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagram of the structure of an exemplary thin film sensor.

[0036] Figure 2 for Figure 1 The cross-sectional structure diagram of the thin film sensor along the AA' direction is shown.

[0037] Figure 3 FIG. 4 is a perspective view of a thin film sensor according to an embodiment of the present disclosure.

[0038] Figure 4 FIG. 4 is a top view of a metal line in a thin film sensor according to an embodiment of the present disclosure.

[0039] Figure 5 for Figure 3 Schematic diagram of the cross-sectional structure of the thin film sensor in the BB' direction.

[0040] Figure 6 for Figure 5 The optical transmittance simulation diagram of the thin film sensor is shown.

[0041] Figure 7 FIG. 4 is another schematic diagram of a cross-sectional structure of a thin film sensor according to an embodiment of the present disclosure.

[0042] Figure 8 FIG. 4 is another schematic diagram of a cross-sectional structure of a thin film sensor according to an embodiment of the present disclosure.

[0043] Figure 9 FIG. 4 is another schematic diagram of a cross-sectional structure of a thin film sensor according to an embodiment of the present disclosure.

[0044] Figure 10 FIG. 4 is another schematic diagram of a cross-sectional structure of a thin film sensor according to an embodiment of the present disclosure.

[0045] Figure 11 for Figure 7 and 8 The optical transmittance simulation diagram of the thin film sensor is shown.

[0046] Figure 12 FIG. 4 is another schematic diagram of a cross-sectional structure of a thin film sensor according to an embodiment of the present disclosure.

[0047] Figure 13 for Figure 12 The optical transmittance simulation diagram of the thin film sensor is shown.

[0048] Figure 14 FIG. 4 is another schematic diagram of a cross-sectional structure of a thin film sensor according to an embodiment of the present disclosure.

[0049] Figure 15 FIG. 4 is another schematic diagram of a cross-sectional structure of a thin film sensor according to an embodiment of the present disclosure.

[0050] Figure 16 for Figure 14 The optical transmittance simulation diagram of the thin film sensor is shown.

[0051] Figure 17 for Figure 14 The optical transmittance simulation diagram of the thin film sensor shown is under different incident angles of light. DETAILED DESCRIPTION

[0052] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0053] Unless otherwise defined, the technical or scientific terms used in this disclosure should have the usual meanings understood by people with ordinary skills in the field to which this disclosure belongs. The words "first", "second" and similar terms used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one", "an" or "the" do not indicate a quantity limitation, but rather indicate the presence of at least one. Words such as "include" or "comprise" mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may 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 object being described changes, the relative positional relationship may also change accordingly.

[0054] Figure 1 is a schematic structural diagram of an exemplary thin film sensor; Figure 2 for Figure 1 The cross-sectional structure diagram of the thin film sensor along the AA' direction is shown in FIG. Figure 1 and Figure 2 As shown, the thin film sensor includes: a base substrate 100 having a first surface and a second surface (i.e., an upper surface and a lower surface) disposed opposite each other; a first conductive layer 101 and a second conductive layer 102 located on the first and second surfaces of the base substrate 100, respectively. For example, in the case of a thin film sensor as a transparent antenna, the first conductive layer 101 can be a radiating layer, and the second conductive layer 102 can be a grounding layer. The radiating layer can serve as either a receiving element or a transmitting element of the antenna structure.

[0055] In order to ensure that the first conductive layer 101 and the second conductive layer 102 have good light transmittance, the first conductive layer 101 and the second conductive layer 102 need to be patterned. For example, the first conductive layer 101 can be composed of grid lines made of metal materials, and the second conductive layer 102 can also be composed of grid lines made of metal materials. It is understandable that the first conductive layer 101 and the second conductive layer 102 can also be composed of structures with other patterns, such as block electrodes with diamond, triangle and other patterns, which are not listed here one by one. Figure 1As can be seen, the first conductive layer 101 and the second conductive layer 102, i.e., the grid lines, are not disposed across the entire surface of both surfaces of the base substrate 100. Each grid line is formed by an electrically connected metal mesh. Due to the material and formation process of the metal mesh, the line width of the metal mesh is relatively wide, significantly affecting the light transmittance of the thin-film sensor, thereby impacting the user experience.

[0056] It should also be noted that the thin film sensor is not limited to being used in antenna structures, but can also be used in touch panels as touch electrodes. Of course, the thin film sensor can also be used in various metal wires, which will not be listed here.

[0057] To address the aforementioned technical issues, the present disclosure provides the following technical solutions. Before introducing the thin film sensors of the present disclosure, it should be noted that the thin film sensors of the present disclosure are made of conductive materials with low transmittance, including but not limited to metals, metal oxides, graphene, and the like. Similarly, the conductive wires are made of materials including but not limited to metals, metal oxides, graphene, and the like. The following description uses metal wires as an example, but it should be understood that this does not constitute a limitation of the present disclosure.

[0058] Firstly, Figure 3 is a perspective view of a thin film sensor according to an embodiment of the present disclosure; Figure 4 is a top view of a metal line 200 in a thin film sensor according to an embodiment of the present disclosure; Figure 5 for Figure 3 The cross-sectional structure diagram of the thin film sensor in the BB' direction is shown. The embodiment of the present disclosure provides a thin film sensor, which may include a base substrate 100, and a plurality of metal wires 200 and a functional structure arranged crosswise on the base substrate 100. Part of the plurality of metal wires 200 extends along the first direction X and is arranged side by side along the second direction Y, and the remaining part of the metal wires 200 extends along the second direction Y and is arranged side by side along the first direction X. The first direction X and the second direction Y intersect, and the hollow area defined by the two is arranged corresponding to the hollow portion defined by the intersection of the metal wires 200, and its shape includes but is not limited to a rhombus. In the embodiment of the present disclosure, the functional structure is configured to emit at least part of the light transmitted along a preset direction and incident on the functional structure from the area where the conductive wire is located through the hollow portion; wherein the preset direction is the direction from the base substrate 100 to the metal wires 200.

[0059] Since a functional structure is provided in the thin film sensor of the embodiment of the present disclosure, and the functional structure is capable of emitting at least a portion of the light transmitted along a preset direction and incident on the functional structure from the area where the conductive wire is located through the hollow portion, that is, under the action of the functional structure, at least a portion of the light irradiated to the area where the conductive wire is located can bypass the metal wire 200 and be emitted, thereby greatly improving the light transmittance.

[0060] In order to make the structure of the thin film sensor in the embodiment of the present disclosure clearer, the thin film sensor in the embodiment of the present disclosure is described below with reference to specific examples.

[0061] In one example, if Figure 5 As shown, the functional structure of the thin film sensor includes a first dielectric layer 300 disposed between the metal lines 200 and the layer containing the base substrate 100. The thin film sensor also includes a planarization layer 500 covering the side of the layer containing the metal lines 200 facing away from the base substrate 100. The first dielectric layer 300 includes multiple first main portions 301 arranged in a crosswise manner, with each first main portion 301 overlapping the orthographic projection of a metal line 200 on the base substrate 100. For example, each first main portion 301 corresponds to each metal line 200, and the orthographic projection of the first main portion 301 and the metal line 200 on the base substrate 100 completely overlap. In other words, the pattern of the first dielectric layer 300 is identical to the pattern defined by the multiple metal lines 200. In this case, the planarization layer 500 not only covers the metal lines 200, but also covers the sidewalls of the first main portion 301 with the material of the planarization layer 500 falling within the hollow portion. In this thin film sensor structure, the refractive index of the planarization layer 500 is greater than the refractive index of the first dielectric layer 300 , that is, the refractive index of the planarization layer 500 is greater than the refractive index of the first main body 301 .

[0062] Continue to refer to Figure 5In the thin film sensor of the disclosed embodiment, the main bodies of the metal lines 200 and the first dielectric layer 300 are arranged in a one-to-one correspondence, with the first main body 301 located below the metal lines 200 (on the side closest to the base substrate 100). Both are located in the area where the conductive lines are located. A planarization layer 500 covers the metal lines 200. This planarization layer 500 is located in the area where the conductive lines are located and in the hollowed-out areas, filling the hollowed-out areas of the thin film sensor to flatten the surface of the thin film sensor. In this case, the sidewalls of the first main body 301 are in contact with the planarization layer 500. Furthermore, in the disclosed embodiment, the refractive index of the first main body 301 is lower than that of the planarization layer 500. In this way, when part of the light emitted from the preset direction will illuminate the area where the conductive wire of the thin film sensor is located, since the refractive index of the first main body 301 is lower than the refractive index of the planarization layer 500, and when the light passes through a medium with an uneven refractive index, a similar diffraction effect will occur. That is, after the light enters the first main body 301, part of the light will be transmitted to the planarization layer 400 with a relatively high refractive index, that is, bypassing the metal wire 200, entering the hollow part and being emitted through the hollow part, thereby avoiding the light from being directly absorbed or reflected by the metal wire 200, thereby greatly improving the light transmittance.

[0063] In some examples, the materials of the first dielectric layer 300 and the planarization layer 400 can both be organic optically transparent materials or inorganic optically transparent materials. Organic optically transparent materials include, but are not limited to, COP, polyethylene terephthalate / PET, OCA adhesive, optical plastic CR-39, cured PMMA, SU8, AZ5214, and the like; inorganic optically transparent materials include, but are not limited to, SiO, Al2O3, ZnO, SiN, and the like. Of course, it should be understood that as long as the refractive index of the optically transparent material selected for the first dielectric layer 300 is lower than that of the optically transparent material selected for the planarization layer 400, it is within the scope of protection of the presently disclosed embodiments.

[0064] Continue to refer to Figure 5, the first main body portion 301 has a first cross-section perpendicular to the extension direction. The first cross-section is rectangular. In order to ensure a sufficient diffraction propagation distance, the thickness of the first main body portion 301 with a rectangular first cross-section is generally required to be thicker. In some examples, the height of the first cross-section is at least 1.5 times the width, and optionally 2 times or even more than 2 times. That is, the thickness of the first main body portion 301 is at least 1.5 times its line width. Within a reasonable range, the thicker the thickness of the first main body portion 301, the higher the transmittance of the thin film sensor. For example: the metal line 200 is made of silver with a line width of 3μm and a thickness of 60nm; the line width of the first main body 301 is the same as the metal line 200, which is 3μm. At this time, the thickness of the first main body 301 is selected as 6μm and 11.5μm respectively; the refractive index of the first main body 301 in the visible light band is 1.53 (at this time, the first main body 301 uses COP), and the refractive index of the planarization layer 400 in the visible light band is 1.6 (at this time, the planarization layer 400 uses OCA glue). Figure 6 As can be seen, the light is blocked by the 3μm wide metal wire 200, and the maximum transmittance of light within the 3μm width is only 17% ( Figure 6 After the compensation of the first dielectric layer 300, the peak transmittance can be increased to nearly 28% ( Figure 6 The transmittance is also closely related to the thickness of the first dielectric layer 300 (first main body 301), such as Figure 6 As shown, it is easier to obtain a higher transmittance when the first dielectric layer 300 with a thickness of 11.5 μm intersects with the first dielectric layer 300 with a thickness of 6 μm ( S103 ).

[0065] It should be noted that the above description is based on the example that the first cross-section of the first main body 301 is a rectangle. In actual products, the shape of the first main body 301 is not limited to a rectangle, but can also be any shape such as an inverted triangle, an inverted trapezoid, a semi-ellipse, etc., which are not listed one by one here.

[0066] In view of the above-mentioned thin film sensor structure, an embodiment of the present disclosure further provides a method for preparing the thin film sensor, which includes the following steps.

[0067] S11, providing a base substrate 100.

[0068] The base substrate 100 may be made of a flexible film, and the flexible film material may be at least one of a COP film, polyimide (PI) or polyethylene terephthalate (PET).

[0069] S12 , forming a pattern including a first dielectric layer 300 on the base substrate 100 .

[0070] Taking the first dielectric layer 300 as an example, in which an organic curing adhesive that can be cured at low temperature is used, in step S12, a layer of organic curing adhesive and photoresist can first be coated on the base substrate 100, and then the organic curing adhesive corresponding to the hollow portion is removed through exposure, development, and etching processes. Finally, the remaining organic curing adhesive material is cured at low temperature to form the first dielectric layer 300 having a cross-arranged first main body portion 301.

[0071] S13 , forming a pattern of metal lines 200 on the base substrate 100 with the first dielectric layer 300 formed thereon through a communication process.

[0072] Specifically, step S13 may include forming a metal film on the side of the first dielectric layer 300 facing away from the base substrate 100 by means including but not limited to sputtering, and coating it with photoresist, and then removing the metal material corresponding to the hollow portion by exposure, development, and etching processes to form a plurality of cross-arranged metal lines 200.

[0073] S14 , forming a planarization layer 400 on the base substrate 100 on which the metal lines 200 are formed.

[0074] In step S14 , the planarization layer 400 may be formed by deposition using plasma enhanced chemical vapor deposition, low pressure chemical vapor deposition, atmospheric pressure chemical vapor deposition, or electron cyclotron resonance chemical vapor deposition.

[0075] This is completed Figure 5 Preparation of the thin film sensor shown.

[0076] In another example, Figure 7-10 FIG. 1 is another cross-sectional structural diagram of a thin film sensor according to an embodiment of the present disclosure. Figure 7-10 As shown, the functional structure of this thin film sensor includes not only a first dielectric layer 300 but also a second dielectric layer 500, with the refractive index of the second dielectric layer 500 being greater than that of the first dielectric layer 300. The second dielectric layer 500 has a plurality of intersecting first grooves. The first main body of the first dielectric layer 300 is disposed within a first groove, with each first main body 301 corresponding to a first groove, for example, a one-to-one correspondence between each first main body 301 and a first groove. The metal wire 200 is located on the side of the first main body 301 facing away from the base substrate 100.

[0077] Continue to refer to Figure 7Because the first main body 301 is disposed in the first groove, the sidewalls of the first main body 301 are enclosed by the second dielectric layer 500. When part of the light emitted from a predetermined direction strikes the area where the conductive wires of the thin-film sensor are located, the refractive index of the first dielectric layer 300 is lower than that of the second dielectric layer 500. A similar diffraction effect occurs when light passes through a medium with an uneven refractive index. That is, after entering the first main body 301, part of the light is transmitted through the second dielectric layer 500, which has a relatively high refractive index. This bypasses the metal wires 200, enters the hollow portion, and exits through the hollow portion. This prevents the light from being directly absorbed or reflected by the metal wires 200, significantly improving light transmittance.

[0078] In some examples, the first dielectric layer 300 may be Figure 5 The same material as the first dielectric layer 300 in the thin film sensor shown in FIG. The second dielectric layer 500 can be made of the same type of material as the first dielectric layer 300, that is, the material of the second dielectric layer 500 can also be made of an organic optically transparent material or an inorganic optically transparent material. Among them, organic optically transparent materials include but are not limited to COP, PET, OCA glue, optical plastic CR-39, cured PMMA, SU8, AZ5214, etc.; inorganic optically transparent materials include but are not limited to SiO, Al2O3, ZnO, SiN, etc. Of course, it should be understood that as long as the refractive index of the optically transparent material selected for the first dielectric layer 300 is lower than the refractive index of the optically transparent material selected for the second dielectric layer 500, it is within the scope of protection of the embodiments of the present disclosure.

[0079] In some examples, a planarization layer 400 is further provided on the side of the metal line 200 facing away from the substrate 100. The planarization layer 400 can be made of the same material as the second dielectric layer 500, or a transparent optical material having a refractive index that differs from that of the second dielectric layer 500 by no more than 0.2.

[0080] In some examples, due to process reasons, the shape of the first groove portion formed in the second dielectric layer 500 is usually a non-rectangular groove. Accordingly, the first cross-section of the first main body portion 301 of the formed first dielectric layer 300 is also not rectangular. That is, the first cross-section includes a top edge arranged opposite to the base substrate 100, and at least one side edge connected to the top edge, and at this time, the angle between the tangent line of any point on the side edge and the top edge of the base substrate 100 is not greater than 90°. Specifically, when the first groove portion is an inverted triangular groove, the corresponding first cross-section of the first main body portion 301 is an inverted triangle, such as Figure 7 When the first groove portion is in the shape of an inverted trapezoid, the first cross section of the corresponding first main body portion 301 is in the shape of an inverted trapezoid, as shown in FIG. Figure 8 When the first groove portion is semi-elliptical, the first cross section of the corresponding first main body portion 301 is semi-elliptical, as shown in FIG. Figure 9 As shown. It can be seen that the first main body portion 301 is compatible with the first groove portion. Figure 10 As shown, when the first main body portion 301 is formed, due to process reasons, the surface of the first main body portion 301 facing away from the base substrate 100 may not be flat, so a flat portion 302 is formed on the surface of the first main body portion 301 facing away from the base substrate 100 through a leveling process. That is, the first dielectric layer 300 includes not only the first main body portion 301, but also the flat portion 302 connected to the first main body portion 301.

[0081] Taking a thin film sensor having a first main body 301 with a first cross section of an inverted triangle or an inverted trapezoid as an example, the effect of providing the first dielectric layer 300 and the second dielectric layer 500 on improving the transmittance of the thin film sensor is described.

[0082] When the line width of the metal wire 200 is 3μm, the line width of the first main body 301 with a first cross-section of an inverted triangle is also 3μm, and the height of the first cross-section of the triangle is 8μm, that is, the thickness of the first main body 301 is 8μm. When the line width of the metal wire 200 is 3μm, the line width of the surface of the first main body 301 with a first cross-section of an inverted trapezoid that contacts the metal wire 200 is also 3μm, the line width of the surface away from the metal wire 200 is 1μm, and the height of the first cross-section of the trapezoid is 5μm, that is, the thickness of the first main body 301 is 5μm. The refractive index of the first main body 301 (first dielectric layer 300) with a first cross-section of an inverted triangle and an inverted trapezoid is 1.48, and the refractive index of the second dielectric layer 500 is 1.6; that is, the refractive index difference between the first dielectric layer 300 and the second dielectric layer 500 is 0.12. As Figure 11 As shown, after the compensation of the first main body portion 301 having a first cross-section of an inverted triangle, the transmittance of light has reached more than 90% in the entire visible light band ( Figure 11 The first main body 301 with the first cross section of the inverted trapezoid also increases the optical transmittance from 17% ( Figure 11 S201) increased to more than 55% ( Figure 11 S203 in ).

[0083] The following also provides methods for fabricating thin-film sensors whose functional structure includes a first dielectric layer 300 and a second dielectric layer 500. One method can form a rectangular first groove, while the other method can form a non-rectangular first groove. These two methods are described below.

[0084] A method for manufacturing a thin film sensor having a rectangular first groove may include the following steps.

[0085] S21 , providing a base substrate 100 .

[0086] The base substrate 100 may be made of a flexible film, and the flexible film material may be at least one of a COP film, polyimide (PI) or polyethylene terephthalate (PET).

[0087] S22 , forming a pattern including the second dielectric layer 500 on the base substrate 100 through a patterning process.

[0088] Step S22 may specifically include forming a second material layer on the base substrate 100 , coating a photoresist on the second material layer, and then exposing, developing, and etching to form a second dielectric layer 500 having a rectangular first groove portion.

[0089] S23 , forming a pattern including the first dielectric layer 300 and the metal line 200 on the second dielectric layer 500 facing away from the base substrate 100 .

[0090] Step S23 may specifically include coating a first material layer and a metal material layer in sequence on the side of the second dielectric layer 500 facing away from the base substrate 100, wherein the thicknesses of the first material layer and the metal material layer are much smaller than the thickness of the second material layer. At this time, the first material layer and the metal material layer falling into the first groove portion are disconnected from the first material layer and the metal material layer covering the outside of the first groove portion; thereafter, the metal material layer outside the first groove portion can be peeled off with a strong adhesive tape to form a metal wire 200 and a first main body portion 301 located below the metal wire 200.

[0091] S24 , forming a planarization layer 400 on the base substrate 100 on which the metal lines 200 are formed.

[0092] In step S14 , the planarization layer 400 may be formed by deposition using plasma enhanced chemical vapor deposition, low pressure chemical vapor deposition, atmospheric pressure chemical vapor deposition, or electron cyclotron resonance chemical vapor deposition.

[0093] The thin film sensor having the rectangular first groove portion is now completed.

[0094] A method for forming a thin film sensor having a first groove portion having a non-rectangular shape may include the following steps. Figure 10 In the example, the first groove portion is an inverted trapezoidal shape, and the first dielectric layer 300 includes a first main portion 301 and a flat portion 302 .

[0095] S31 , providing a base substrate 100 .

[0096] The base substrate 100 may be made of a flexible film, and the flexible film material may be at least one of a COP film, polyimide (PI) or polyethylene terephthalate (PET).

[0097] S32 , forming a pattern including the second dielectric layer 500 on the base substrate 100 through a patterning process.

[0098] Step S32 may specifically include forming a second material layer on the base substrate 100 , coating photoresist on the second material layer, and then exposing, developing, and etching to form a second dielectric layer 500 having an inverted trapezoidal first groove portion.

[0099] S33 , forming a first dielectric layer 300 on the second dielectric layer 500 facing away from the base substrate 100 .

[0100] Step S33 may specifically include sequentially coating a first material layer on the side of the second dielectric layer 500 facing away from the base substrate 100. At this time, the first material layer fills the first groove to form the first main body 301 on the side of the first dielectric layer 300, and the first material layer covering the second dielectric layer 500 forms the flat portion 302 of the first dielectric layer 300, thereby forming the first dielectric layer 300.

[0101] S34 , forming a pattern including the metal line 200 on the base substrate 100 with the first dielectric layer 300 formed thereon by a patterning process.

[0102] Step S34 may specifically include forming a metal film on the side of the first dielectric layer 300 facing away from the base substrate 100 by methods including but not limited to sputtering, and coating it with photoresist, and then removing the metal material corresponding to the hollow portion by exposure, development, and etching processes to form a plurality of cross-arranged metal lines 200.

[0103] The preparation of the thin film sensor is now completed.

[0104] It should be noted that, after step S34 , a step of forming a planarization layer 400 may be further included, and the forming method is the same as the above-mentioned step of forming the planarization layer 400 , so it will not be described again here.

[0105] In another example, Figure 12 FIG. 1 is another cross-sectional structural diagram of a thin film sensor according to an embodiment of the present disclosure. Figure 12 As shown, the structure of this thin film sensor is similar to the above Figure 5 The structures of the thin film sensors shown are substantially the same, differing only in that the first main structure of the first dielectric layer 300 is doped with micro-nano scattering particles 304 or micro-nano scattering voids to further increase optical transmittance. The micro-nano scattering particles include, but are not limited to, metal particles or dielectric material particles.

[0106] Reference Figure 12, the line width of the metal line 200 in the thin film sensor is 3μm, the line width of the first main body 301 is also 3μm, and the thickness is 11μm. The first main body 301 is uniformly doped with metal micro-nanoparticles with scattering centers of 10nm to 100nm in diameter, or dielectric nanoparticles with a higher refractive index than the first main body 301, or air pores with a lower refractive index than the first main body 301, etc. Figure 13 As shown, it can be seen that the optical transmittance can be increased from 0.17 ( Figure 13 S301 in) increased to 0.27( Figure 13 (S302 in ).

[0107] In some examples, dielectric nanoparticles having a higher refractive index than the first main body 301 may include titanium dioxide particles or silicon sphere particles, etc. Of course, it is also possible to design the shape of the dielectric material particles and simultaneously excite the resonance of the electric dipole and the magnetic dipole to produce zero backscattering, thereby further improving the optical forward scattering and thus improving the optical transmittance. It should be noted here that when metal micro-nanoparticles are doped in the first main body 301, the density of the metal micro-nanoparticles cannot be too large. This is because the ohmic loss of the metal is strong and there is a reflection effect. Too many metal micro-nanoparticles will result in reflection and absorption of energy rather than forward transmission. Preferably, the diameter of the metal micro-nanoparticles is between 10nm and 100nm, and the concentration of the metal micro-nanoparticles is approximately 1 to 2 per cubic micron.

[0108] In addition, the above description is based on the example that the first cross section of the first main body 301 is rectangular. Figure 7-10 Doping micro-nano scattering particles or micro-nano scattering voids in the first main body 301 can effectively improve the optical transmittance.

[0109] In another example, Figure 14 FIG. 1 is another cross-sectional structural diagram of a thin film sensor according to an embodiment of the present disclosure. Figure 14As shown, the functional structure of the thin film sensor includes a third dielectric layer 600 disposed between the metal wire 200 and the layer of the base substrate 100. The thin film sensor also includes a fourth dielectric layer 700 located between the third dielectric layer 600 and the metal wire 200. The third dielectric layer 600 includes multiple cross-arranged second main portions; a second main portion overlaps with the orthographic projection of a metal wire 200 on the base substrate 100. For example, a second main portion and a metal wire 200 are disposed in a one-to-one correspondence, and their orthographic projections on the base substrate 100 overlap. The third dielectric layer 600 is capable of reflecting light, but it also requires a certain degree of light transmittance. Because the third dielectric layer 600 and the metal wire 200 are disposed opposite each other and separated by a certain distance, the third dielectric layer 600 (second main portion) and the metal wire 200 form an optical microcavity. In this case, when light enters the optical microcavity, it is reflected by the second main portion and the metal wire 200, changing its propagation direction, ultimately bypassing the metal wire 200 and exiting through the hollow portion.

[0110] In some examples, the overlapping area between the second main body and the metal line 200 is no more than 10% of the area of ​​the metal line 200 . By properly setting the overlapping area between the second main body and the metal line 200 , light can be well transmitted.

[0111] In some examples, the third dielectric layer 600 includes, but is not limited to, any one of a metal film, a semi-transparent film, and a distributed Bragg reflector (DBR). For example, the third dielectric layer 600 can be a metal silver film with a thickness of 10 nm to 40 nm.

[0112] In some examples, the material of the metal wire 200 includes, but is not limited to, at least one of aluminum, copper, silver, and gold. When the reflectivity of the metal wire 200 is low, a reflective sheet 800 can be formed on the side of the metal wire 200 near the second main body. For example, a thin silver or aluminum film can be formed as the reflective sheet 800 to enhance the reflectivity of the metal wire 200. This allows light to be reflected between the metal wire 200 and the second main body, changing the light transmission direction and thereby improving the optical transmittance of the thin film sensor.

[0113] In some examples, the thin film sensor further includes a planarization layer 400 covering the side of the plurality of metal lines 200 facing away from the base substrate 100; the difference in refractive index between the planarization layer 400 and the fourth dielectric layer 700 is no greater than 0.05. Preferably, the planarization layer 400 and the fourth dielectric layer 700 are made of the same material to ensure there is no refractive index difference between the fourth dielectric layer 700 and the planarization layer 400, thereby minimizing interfacial reflection when light leaks from the optical microcavity into the planarization layer 400, which could reduce optical diffraction efficiency.

[0114] for Figure 14 In the thin film sensor shown, the optical microcavity forms an anti-reflection layer for light waves in a specific wavelength band. Assuming the energy of the incident light is 1, the energy diffracted and transmitted through the metal wire 200 is 1-reflectivity-absorption rate. When the reflectivity is greatly reduced by the optical microcavity, the energy ratio of the diffracted light transmitted through the metal wire 200 can be increased accordingly. After the optical microcavity is formed, at the resonant wavelength of visible light, more incident light energy is concentrated in the optical microcavity and diffracted from the left and right openings of the optical microcavity to pass through the top metal wire 200. At the non-resonant point, more electromagnetic energy is directly reflected, thereby reducing the probability of diffraction transmission.

[0115] It should be noted that the thicker the optical microcavity, the more wavelengths that can produce anti-reflection; at the same time, the spectrum of each resonance wavelength of the optical microcavity is generally narrow, so the resonance wavelength is very sensitive to the thickness of the optical microcavity. A thickness change of tens of nanometers can cause a significant shift in the resonance peak. Figure 16 , the thickness of the optical microcavity changes from 1.6μm to 1.55μm, and the wavelengths of the various resonance peaks move significantly ( Figure 16 S402 in the figure is moved to S403). Figure 16 At the resonant wavelength, due to the enhanced diffraction effect, the transmittance of the metal wire 200 can be increased from 0.17 ( Figure 16 S401) increased to 0.32( Figure 16 The thickness of the optical microcavity is determined by the thickness of the fourth dielectric layer 700, so it is particularly important to reasonably set the thickness of the fourth dielectric layer 700.

[0116] In addition, the method of using an optical resonant cavity to compensate for the transmittance of the metal wire 200 is particularly sensitive to the incident angle. Figure 13 As can be seen from the figure, the wavelength of the resonance peak shifts significantly when the incident angle changes from 0° to only 5° (e.g. Figure 17 As the incident angle continues to increase, the shift of the resonance peak wavelength will become larger and larger.

[0117] It will be understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the present invention, and the present invention is not limited thereto. Those skilled in the art will appreciate that various modifications and improvements can be made without departing from the spirit and substance of the present invention, and such modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A thin film sensor comprising: substrate; A plurality of conductive lines are arranged on the base substrate, and the plurality of conductive lines are arranged to cross each other to define a plurality of hollow portions; A functional structure is provided on the base substrate; wherein the functional structure is configured to emit at least a portion of light transmitted along a preset direction and incident on the functional structure from the region where the conductive line is located out through the hollow portion; wherein the preset direction is the direction from the base substrate to the conductive line; The functional structure includes: a first dielectric layer provided on a side of the conductive line close to the substrate; the first dielectric layer includes a plurality of first main bodies arranged crosswise; one of the first main bodies overlaps with an orthographic projection of one of the conductive lines on the substrate; The thin film sensor further includes: a planarization layer covering the side of the plurality of conductive lines facing away from the base substrate, wherein a portion of the planarization layer falling into the hollow portion covers a sidewall of the first main body portion; and a refractive index of the first dielectric layer is smaller than a refractive index of the planarization layer.

2. The thin film sensor according to claim 1, wherein The functional structure further includes: a second dielectric layer provided on the base substrate; the refractive index of the first dielectric layer is smaller than the refractive index of the second dielectric layer; The second dielectric layer includes a plurality of first grooves arranged crosswise; one first main body is filled in one of the first grooves.

3. The thin film sensor according to claim 2, wherein: The functional structure further includes a first flat portion; the first flat portion is located between the conductive wire and the second dielectric layer, and is connected to the plurality of first main body portions to form an integrated structure.

4. The thin film sensor according to claim 2, wherein The difference in refractive index between the planarization layer and the second dielectric layer is no more than 0.

2.

5. The thin film sensor according to any one of claims 1 to 4, wherein: The thickness of the first body portion is at least 1.5 times its maximum width.

6. The thin film sensor according to any one of claims 1 to 4, wherein: Micro-nano scattering particles or micro-nano scattering voids are doped in the first main body.

7. The thin film sensor according to any one of claims 1 to 4, wherein: The first main body has a first cross-section perpendicular to its extension direction; the first cross-section has at least one side edge away from the top edge of the base substrate and connected to the top edge; the angle between the tangent line at any point on the side edge and the top edge of the base substrate is not greater than 90°.

8. The thin film sensor according to claim 7, wherein The shape of the first cross section includes any one of an inverted trapezoid, an inverted triangle, and a semi-ellipse.

9. The thin film sensor according to claim 1, wherein The functional structure further includes a third dielectric layer; the third dielectric layer is provided on the substrate, and a fourth dielectric layer is provided between the third dielectric layer and the layer where the conductive wires are located; The third dielectric layer includes a plurality of second main body portions arranged crosswise; one of the second main body portions overlaps with an orthographic projection of one of the conductive lines on the base substrate.

10. The thin film sensor according to claim 9, wherein The second main body includes any one of a metal film, a semi-reflective and semi-transmissive film, and a distributed Ragg reflector.

11. The thin film sensor according to claim 9, wherein The difference in refractive index between the planarization layer and the fourth dielectric layer is no more than 0.

05.

12. The thin film sensor according to claim 9, wherein A reflective sheet is provided on a side of the conductive line opposite to the second main body portion.

13. A method for preparing a thin film sensor, wherein the thin film sensor is as described in any one of claims 1 to 12; The preparation method comprises: A plurality of intersecting conductive lines and functional structures are formed on a substrate; wherein the plurality of intersecting conductive lines define a plurality of hollow portions; the functional structure is configured to emit at least a portion of light transmitted along a preset direction and incident on the functional structure from the region where the conductive lines are located, out of the hollow portions; wherein the preset direction is the direction from the substrate toward the conductive lines; The functional structure includes a first dielectric layer provided on a side of the conductive line close to the substrate; the first dielectric layer includes a plurality of first main body portions arranged crosswise; the step of forming the functional structure includes forming the first dielectric layer, and the step of forming the first dielectric layer includes: On a side of the conductive line close to the base substrate, a plurality of first main body portions are formed that are cross-arranged, and one of the first main body portions overlaps with an orthographic projection of a conductive line to be formed on the base substrate; The thin film sensor further includes a planarization layer covering a side of the plurality of conductive lines facing away from the base substrate, and the preparation method further includes: A pattern including the planarization layer is formed on a side of the first dielectric layer facing away from the base substrate; a portion of the planarization layer falling into the hollow portion covers a sidewall of the first main portion, and a refractive index of the first dielectric layer is less than a refractive index of the planarization layer.

14. The method for preparing a thin film sensor according to claim 13, wherein: The functional structure further includes: a second dielectric layer provided on the substrate; the refractive index of the first dielectric layer is less than the refractive index of the second dielectric layer; and the step of forming the functional structure further includes: The second dielectric layer is formed on the side of the conductive line close to the base substrate; the first dielectric layer is located between the second dielectric layer and the conductive line; the second dielectric layer includes a plurality of first grooves arranged crosswise; and one first main body is filled in one of the first grooves.

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