CN112420791A

CN112420791A - Fingerprint identification substrate, preparation method thereof and display device

Info

Publication number: CN112420791A
Application number: CN202011281186.4A
Authority: CN
Inventors: 耿越; 李成; 王奎元; 祁朝阳; 丰亚洁; 代翼; 李泽飞; 李想
Original assignee: BOE Technology Group Co Ltd; Beijing BOE Sensor Technology Co Ltd
Current assignee: BOE Technology Group Co Ltd; Beijing BOE Sensor Technology Co Ltd
Priority date: 2020-11-16
Filing date: 2020-11-16
Publication date: 2021-02-26
Anticipated expiration: 2040-11-16
Also published as: CN112420791B

Abstract

The disclosure provides a fingerprint identification substrate, a manufacturing method thereof and a display device. Fingerprint identification base plate includes the basement, sets up fingerprint sensing layer on the basement is kept away from with setting up at fingerprint sensing layer the collimation optical filtering structure layer of basement one side, collimation optical filtering structure layer includes along keeping away from the unthreaded hole layer, the light modulation layer and the lens layer that the basement direction set gradually, the light modulation layer is used for the adjustment the focus on lens layer and infrared ray cut off. This is disclosed through being integrated as collimation light filtering structure layer with photic aperture layer, light modulation layer and lens layer, and the light modulation layer that sets up between photic aperture layer and lens layer both is used for cutting off outside infrared ray, is arranged in the focus of lens in the adjustment lens layer again, has effectively reduced fingerprint identification substrate thickness, has effectively solved the great problem of current fingerprint identification module thickness.

Description

Fingerprint identification substrate, preparation method thereof and display device

Technical Field

The present disclosure relates to but not limited to the field of display technologies, and in particular, to a fingerprint identification substrate, a manufacturing method thereof, and a display device.

Background

Fingerprint recognition of display devices (e.g., notebook computers, tablet computers, mobile phones, etc.) is gradually changing from capacitive fingerprint recognition to optical fingerprint recognition. The optical fingerprint identification is to image the fingerprint of a user by utilizing the refraction and reflection of light rays, then identify the fingerprint characteristics by an image identification method, has the characteristics of high imaging resolution, easier image identification and the like, and can be arranged below a display screen to form the fingerprint identification under the screen.

The optical fingerprint module of present volume production is single-finger type silica-based CMOS detector, is subject to semiconductor device manufacturing cost and the technology degree of difficulty, and silica-based CMOS fingerprint module is difficult to the development of large tracts of land screen orientation down. At present, in the fingerprint technology under the glass base screen, the fingerprint identification module that has optical collimator possesses better performance, is favorable to the development to the direction under the large tracts of land screen. However, due to the addition of the optical collimator, the thickness of the fingerprint identification module of the product is generally larger, and the development trend of light and thin display devices is not met.

Disclosure of Invention

The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

The technical problem to be solved by the present disclosure is to provide a fingerprint identification substrate, a manufacturing method thereof, and a display device, so as to overcome the defects of the existing structure, such as large thickness.

In order to solve the technical problem, this disclosure provides a fingerprint identification base plate, be in including basement, setting fingerprint sensing layer on the basement is kept away from with setting up at fingerprint sensing layer the collimation filter structure layer of basement one side, collimation filter structure layer includes along keeping away from the unthreaded hole layer, light modulation layer and the lens layer that the basement direction set gradually, light modulation layer is used for adjusting the focus on lens layer and infrared light cut off.

In an exemplary embodiment, the fingerprint sensing layer includes a thin film transistor and a photodiode disposed on the substrate; the thin film transistor includes a gate electrode, an active layer, a source electrode, and a drain electrode, and the photodiode includes a first electrode, a photoelectric conversion layer, and a second electrode; the drain electrode of the thin film transistor and the first electrode of the photodiode are arranged on the same layer.

In an exemplary embodiment, the fingerprint sensing layer further includes a second insulating layer disposed on a side of the thin film transistor away from the substrate, the second insulating layer is provided with a first via hole exposing the first electrode, and the photoelectric conversion layer is connected to the first electrode through the first via hole.

In an exemplary embodiment, the fingerprint sensing layer further includes a planarization layer and a third insulating layer disposed on a side of the second insulating layer away from the substrate, the planarization layer and the third insulating layer are provided with a second via hole exposing the photoelectric conversion layer, and the second electrode is disposed on the third insulating layer and connected to the photoelectric conversion layer through the second via hole.

In an exemplary embodiment, the fingerprint sensing layer further includes a power line disposed on a side of the second electrode away from the substrate, and an orthographic projection of the power line on the substrate includes an orthographic projection of a channel region of the thin film transistor on the substrate.

In an exemplary embodiment, the light hole layer is disposed on a side of the second electrode away from the substrate, and the light hole layer includes at least one light hole forming a light transmission channel.

In an exemplary embodiment, the thickness of the photo-hole layer is 5 μm to 10 μm, and the aperture of the photo-hole is 3 μm to 8 μm.

In an exemplary embodiment, the lens layer is disposed on a side of the light modulation layer away from the substrate, and the lens layer includes at least one lens having a focal point on an axis of the at least one aperture.

In an exemplary embodiment, the thickness of the lens layer is 5 μm to 10 μm.

In an exemplary embodiment, the light modulation layer includes a reflective light modulation layer including at least one first sub-layer and a second sub-layer alternately arranged, a refractive index of the first sub-layer is different from a refractive index of the second sub-layer, and a thickness of the reflective light modulation layer is 30 μm to 50 μm.

In an exemplary embodiment, the light modulation layer includes an absorption type light modulation layer including a cyan photosensitive acrylic resin, and the thickness of the absorption type light modulation layer is 30 μm to 50 μm.

The disclosure also provides a display device comprising the fingerprint identification substrate.

The present disclosure also provides a method for manufacturing a fingerprint identification substrate, including:

forming a fingerprint sensing layer on a substrate;

forming a collimation light filtering structure layer on one side of the fingerprint sensing layer far away from the substrate; collimation light filtering structure layer includes along keeping away from unthreaded hole layer, light modulation layer and the lens layer that the substrate direction set gradually, light modulation layer is used for adjusting the focus on lens layer and cut off infrared light.

In an exemplary embodiment, forming a collimating filter structure layer on the fingerprint sensing layer includes:

forming the photo-aperture layer on the fingerprint sensing layer, the photo-aperture layer including at least one photo-aperture;

forming a light modulation layer on the aperture layer;

forming a lens layer on the light modulation layer, the lens layer including at least one lens having a focal point on an axis of the at least one light aperture.

In an exemplary embodiment, the light modulation layer includes a reflective light modulation layer including at least one first sub-layer and a second sub-layer alternately arranged, the first sub-layer having a refractive index different from that of the second sub-layer; alternatively, the first and second electrodes may be,

the light modulation layer includes an absorption type light modulation layer including cyan photosensitive acrylic resin.

The fingerprint identification base plate that this disclosed exemplary embodiment provided, through with photic aperture layer, light modulation layer and lens layer integration for collimation light filtering structure layer, the light modulation layer that sets up between photic aperture layer and lens layer both had been used for cutting off outside infrared ray, was arranged in the focus of lens in the adjustment lens layer again, has effectively reduced fingerprint identification base plate thickness, has effectively solved the great problem of current fingerprint identification module thickness.

Of course, not all advantages described above need to be achieved at the same time to practice any one product or method of the present disclosure. Additional features and advantages of the disclosure will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the disclosure. The objectives and other advantages of the disclosure may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Other aspects will be apparent upon reading and understanding the attached drawings and detailed description.

Drawings

The accompanying drawings are included to provide an understanding of the present disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the examples serve to explain the principles of the disclosure and not to limit the disclosure.

Fig. 1 is a schematic structural diagram of a fingerprint identification substrate according to an exemplary embodiment of the present disclosure;

FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1;

FIG. 3 is a schematic view after a first conductive layer pattern is formed in an exemplary embodiment of the present disclosure;

FIG. 4 is a cross-sectional view taken along line A-A of FIG. 3;

fig. 5 is a schematic view after patterning a semiconductor layer according to an exemplary embodiment of the present disclosure;

FIG. 6 is a cross-sectional view taken along line A-A of FIG. 5;

fig. 7 is a schematic view after patterning a semiconductor layer according to an exemplary embodiment of the present disclosure;

FIG. 8 is a cross-sectional view taken along line A-A of FIG. 7;

fig. 9 is a schematic view after a second insulation layer pattern is formed according to an exemplary embodiment of the present disclosure;

FIG. 10 is a cross-sectional view taken along line A-A of FIG. 9;

fig. 11 is a schematic view after forming a photoelectric conversion layer pattern according to an exemplary embodiment of the present disclosure;

FIG. 12 is a cross-sectional view taken along line A-A of FIG. 11;

fig. 13 is a schematic view after forming a planarization layer and a third insulation layer pattern according to an exemplary embodiment of the present disclosure;

FIG. 14 is a cross-sectional view taken along line A-A of FIG. 13;

fig. 15 is a schematic view after forming a second electrode pattern according to an exemplary embodiment of the present disclosure;

FIG. 16 is a cross-sectional view taken along line A-A of FIG. 15;

FIG. 17 is a schematic diagram after a power line pattern is formed in an exemplary embodiment of the present disclosure;

FIG. 18 is a cross-sectional view taken along line A-A of FIG. 17;

FIG. 19 is a schematic view after forming a pattern of a light aperture layer according to an exemplary embodiment of the present disclosure;

FIG. 20 is a cross-sectional view taken along line A-A of FIG. 19;

FIG. 21 is a schematic view after forming a light modulation layer pattern according to an exemplary embodiment of the present disclosure;

FIG. 22 is a cross-sectional view taken along line A-A of FIG. 21;

fig. 23 is a transmittance curve of a reflective light modulation layer in accordance with an exemplary embodiment of the present disclosure;

fig. 24 is a transmittance curve of an absorption-type light modulation layer according to an exemplary embodiment of the present disclosure.

Description of reference numerals:

10-a substrate; 11 — a first insulating layer; 12 — a second insulating layer;

13-a planarization layer; 14 — a third insulating layer; 20-scanning signal lines;

21-a gate electrode; 22 — active layer; 23-source electrode;

24-a drain electrode; 30-data signal lines; 31 — a first electrode;

32-a photoelectric conversion layer; 33 — a second electrode; 34-a power line;

41-a photo-porous layer; 42-a light modulation layer; 43-lens layer.

Detailed Description

To make the objects, technical solutions and advantages of the present disclosure more apparent, embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Note that the embodiments may be implemented in a plurality of different forms. Those skilled in the art can readily appreciate the fact that the forms and details may be varied into a variety of forms without departing from the spirit and scope of the present disclosure. Therefore, the present disclosure should not be construed as being limited to the contents described in the following embodiments. The embodiments and features of the embodiments in the present disclosure may be arbitrarily combined with each other without conflict.

In the drawings, the size of each component, the thickness of layers, or regions may be exaggerated for clarity. Therefore, one aspect of the present disclosure is not necessarily limited to the dimensions, and the shapes and sizes of the respective components in the drawings do not reflect a true scale. Further, the drawings schematically show ideal examples, and one embodiment of the present disclosure is not limited to the shapes, numerical values, and the like shown in the drawings.

The ordinal numbers such as "first", "second", "third", and the like in the present specification are provided for avoiding confusion among the constituent elements, and are not limited in number.

In this specification, for convenience, words such as "middle", "upper", "lower", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicating orientations or positional relationships are used to explain positional relationships of constituent elements with reference to the drawings, only for convenience of description and simplification of description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present disclosure. The positional relationship of the components is changed as appropriate in accordance with the direction in which each component is described. Therefore, the words described in the specification are not limited to the words described in the specification, and may be replaced as appropriate.

In this specification, the terms "mounted," "connected," and "connected" are to be construed broadly unless otherwise specifically indicated and limited. For example, it may be a fixed connection, or a removable connection, or an integral connection; can be a mechanical connection, or an electrical connection; either directly or indirectly through intervening components, or both may be interconnected. The specific meaning of the above terms in the present disclosure can be understood in specific instances by those of ordinary skill in the art.

In this specification, a transistor refers to an element including at least three terminals, i.e., a gate electrode, a drain electrode, and a source electrode. The transistor has a channel region between a drain electrode (drain electrode terminal, drain region, or drain electrode) and a source electrode (source electrode terminal, source region, or source electrode), and current can flow through the drain electrode, the channel region, and the source electrode. Note that in this specification, a channel region refers to a region where current mainly flows.

In this specification, the first electrode may be a drain electrode and the second electrode may be a source electrode, or the first electrode may be a source electrode and the second electrode may be a drain electrode. In the case of using transistors of opposite polarities, or in the case of changing the direction of current flow during circuit operation, the functions of the "source electrode" and the "drain electrode" may be interchanged. Therefore, in this specification, "source electrode" and "drain electrode" may be exchanged with each other.

In this specification, "electrically connected" includes a case where constituent elements are connected together by an element having some kind of electrical action. The "element having a certain electric function" is not particularly limited as long as it can transmit and receive an electric signal between connected components. Examples of the "element having some kind of electric function" include not only an electrode and a wiring but also a switching element such as a transistor, a resistor, an inductor, a capacitor, other elements having various functions, and the like.

In the present specification, "parallel" means a state in which an angle formed by two straight lines is-10 ° or more and 10 ° or less, and therefore, includes a state in which the angle is-5 ° or more and 5 ° or less. The term "perpendicular" refers to a state in which the angle formed by two straight lines is 80 ° or more and 100 ° or less, and therefore includes a state in which the angle is 85 ° or more and 95 ° or less.

In the present specification, "film" and "layer" may be interchanged with each other. For example, the "conductive layer" may be sometimes replaced with a "conductive film". Similarly, the "insulating film" may be replaced with an "insulating layer".

"about" in this disclosure means that the limits are not strictly defined, and that the numerical values are within the tolerances allowed for the process and measurement.

The related art provides an optical fingerprint identification module, which adopts a laminated assembly structure of a fingerprint sensing layer, a collimation light path film and a filter film, and the collimation light path film and the filter film are both prepared independently. The filter film is attached to the fingerprint sensing substrate through a first optical Adhesive (OCA), the collimating light path film is attached to the filter film through a second optical Adhesive, the thicknesses of the first optical Adhesive and the second optical Adhesive are both about 25 micrometers, and the thickness of the filter film is about 30 micrometers to 50 micrometers. The collimating optical film in the related art mainly comprises a light hole layer, a spacer (spacer) layer and a lens layer which are stacked, wherein the lens layer is used for gathering fingerprint reflection light, the spacer layer is used for providing a proper focal length for the lens layer, and the light hole layer is used for limiting large-angle incident light gathered by the lens layer. Since the thickness ranges of the aperture layer, the spacer layer, and the lens layer are about 5 μm to 10 μm, 30 μm to 50 μm, and 5 μm to 10 μm, respectively, the total thickness of the collimated light path film is about 40 μm to 70 μm. Thus, the total thickness of the collimating optical path film and the filter film in the fingerprint identification module is about 120 μm to 170 μm, and the total thickness of the fingerprint identification module is about 240 μm to 320 μm.

With the development of mobile terminals (such as mobile phones), the requirement for the compactness of the internal structure of the mobile terminal is higher and higher. In a mobile terminal product, the height between a display screen and a middle frame for placing a fingerprint identification module is required to be not more than 200 mu m. Because the transformation degree of center is lower, therefore the structure of this fingerprint identification module not only can not satisfy the designing requirement, and too thick fingerprint identification module can also seriously disturb mobile terminal's inner structure moreover.

In order to overcome the great problem of current fingerprint identification module thickness, this disclosure provides a fingerprint identification base plate. In an exemplary embodiment, the fingerprint identification base plate can include the basement, set up fingerprint sensing layer on the basement keeps away from with setting up at fingerprint sensing layer the collimation filter structure layer of basement one side, collimation filter structure layer includes along keeping away from unthreaded hole layer, light modulation layer and the lens layer that the basement direction set gradually, light modulation layer is used for adjusting the focus of lens layer and end infrared ray.

Fig. 1 is a schematic structural view of a fingerprint identification substrate according to an exemplary embodiment of the present disclosure, and fig. 2 is a cross-sectional view taken along a-a direction in fig. 1. As shown in fig. 1 and 2, the fingerprint identification substrate includes a base 10, a plurality of scanning signal lines 20 and a plurality of data signal lines 30 disposed on the base 10, the plurality of scanning signal lines 20 and the plurality of data signal lines 30 crossing each other to form a plurality of identification pixels arranged in a matrix. It is understood that the scanning signal lines and the data signal lines intersect as disclosed in the present disclosure means that the projections of the scanning signal lines and the data signal lines on the substrate intersect perpendicularly without direct contact due to the presence of the insulating layer. At least one identification pixel includes fingerprint sensing layer and the collimation filter structure layer of establishing of folding on base 10, the fingerprint sensing layer includes thin film transistor and photodiode, the collimation filter structure layer is including the photic aperture layer 41 of establishing of folding, light modulation layer 42 and lens layer 43, lens layer 43 is used for assembling the reverberation of fingerprint, play the effect of receiving light, light modulation layer 42 is used for cutting off infrared ray on the one hand, in order to avoid external light to disturb normal fingerprint formation of image, on the other hand is used for adjusting the focus of lens layer 43, photic aperture layer 41 is used for restricting the wide-angle incident light after lens layer 43 assembles, thereby reduce and crosstalk.

In an exemplary embodiment, the scan signal line 20 is connected to a Gate integrated circuit (Gate IC) of an external circuit, the data signal line 30 is connected to a read integrated circuit (ROIC) of the external circuit, the Gate IC transmits a fingerprint recognition scan signal to the scan signal line 20, and the read integrated circuit reads an electrical signal from the data signal line 30.

It should be noted that the structures shown in fig. 1 and fig. 2 only illustrate 3 rows and 3 columns of identification pixels, but in practice, the fingerprint identification substrate may include several hundred rows and several hundred columns of identification pixel arrays, and the identification pixel arrays constitute the photosensitive area of the fingerprint identification substrate.

In an exemplary embodiment, the thin film transistor and the photodiode in the fingerprint sensing layer are simultaneously fabricated on the substrate 10. The thin film transistor may include a gate electrode 21, an active layer 22, a source electrode 23, and a drain electrode 24, and the photodiode includes a first electrode 31, a photoelectric conversion layer 32, and a second electrode 33. In the thin film transistor and the photodiode which are simultaneously manufactured, the drain electrode 24 of the thin film transistor and the first electrode 31 of the photodiode may be disposed at the same layer and formed through the same patterning process. In an exemplary embodiment, the drain electrode 24 and the first electrode 31 may be an integral structure connected to each other.

In an exemplary embodiment, the fingerprint sensing layer further includes a second insulating layer 12 covering the thin film transistor, the second insulating layer 12 is provided with a first via hole exposing the first electrode 31 of the photodiode, and the photoelectric conversion layer 32 of the photodiode is connected to the first electrode 31 of the photodiode through the first via hole.

In an exemplary embodiment, the fingerprint sensing layer further includes a flat layer 13 and a third insulating layer 14 covering the second insulating layer 12 and the photoelectric conversion layer 32, the flat layer 13 and the third insulating layer 14 are provided with second via holes exposing the photoelectric conversion layer 32 of the photodiode, and the second electrode 33 of the photodiode is provided on the third insulating layer 14 and connected to the photoelectric conversion layer 32 of the photodiode through the second via holes.

In an exemplary embodiment, a power supply line 34 is disposed on the second electrode 33 of the photodiode, and an orthographic projection of the power supply line 34 on the substrate includes an orthographic projection of a channel region of the thin film transistor on the substrate.

In an exemplary embodiment, the light hole layer 41 is disposed on the second electrode 33 of the second via hole, and the light hole layer 41 includes at least one light hole forming a light transmission channel.

In the exemplary embodiment, the light modulation layer 42 is provided on the aperture layer 41 for cutting off the external infrared light on the one hand and for adjusting the focal lengths of the plurality of lenses in the lens layer 43 on the other hand such that the focal point of each lens is located on the axis of each aperture and the focal point of the lens is located at the midpoint in the depth direction of the aperture. Wherein, the depth of the optical hole may be the size of the optical hole in the direction perpendicular to the substrate plane, and the depth direction of the optical hole may be the direction perpendicular to the substrate plane.

In an exemplary embodiment, the lens layer 43 is disposed on the light modulation layer 42, and the lens layer 43 includes at least one lens, and the at least one lens corresponds to the at least one light hole one by one, and is used for collecting the fingerprint reflection light to perform a light receiving function.

In an exemplary embodiment, the stacked light aperture layer 41, light modulation layer 42, and lens layer 43 may limit a large-angle incident light, may limit an external infrared light, and thus reduce crosstalk.

In an exemplary embodiment, the light modulation layer 42 may be a reflective light modulation layer including at least one first sub-layer and a second sub-layer alternately disposed, the first sub-layer having a refractive index different from that of the second sub-layer, and the reflective light modulation layer may have a thickness of about 30 to 50 μm.

In an exemplary embodiment, the light modulation layer 42 may be an absorption type light modulation layer including cyan photosensitive acrylic resin, and the thickness of the absorption type light modulation layer may be about 30 to 50 μm.

The following is an exemplary description of the manufacturing process of the fingerprint recognition substrate. The "patterning process" referred to in the present disclosure includes processes of coating a photoresist, mask exposure, development, etching, stripping a photoresist, and the like, for a metal material, an inorganic material, or a transparent conductive material, and processes of coating an organic material, mask exposure, development, and the like, for an organic material. The deposition can be any one or more of sputtering, evaporation and chemical vapor deposition, the coating can be any one or more of spraying, spin coating and ink-jet printing, and the etching can be any one or more of dry etching and wet etching, and the disclosure is not limited. "thin film" refers to a layer of a material deposited, coated, or otherwise formed on a substrate. The "thin film" may also be referred to as a "layer" if it does not require a patterning process throughout the fabrication process. If the "thin film" requires a patterning process during the entire fabrication process, it is referred to as "thin film" before the patterning process and "layer" after the patterning process. The "layer" after the patterning process includes at least one "pattern". In the present disclosure, the term "a and B are disposed in the same layer" means that a and B are formed simultaneously by the same patterning process, and the "thickness" of the film layer is the dimension of the film layer in the direction perpendicular to the display substrate. In the exemplary embodiments of the present disclosure, the phrase "the orthographic projection of a includes the orthographic projection of B" means that the boundary of the orthographic projection of B falls within the boundary range of the orthographic projection of a, or the boundary of the orthographic projection of a overlaps with the boundary of the orthographic projection of B.

In an exemplary embodiment, the process of preparing the fingerprint recognition substrate may include the following operations.

(1) A first conductive layer pattern is formed. In an exemplary embodiment, the forming of the first conductive layer pattern may include: a first metal film is deposited on a substrate, and the first metal film is patterned through a patterning process to form a first conductive layer pattern, the first conductive layer pattern at least including a scan signal line 20 and a gate electrode 21, as shown in fig. 3 and 4, and fig. 4 is a cross-sectional view taken along a-a of fig. 3.

In an exemplary embodiment, the scan signal lines 20 may extend in a horizontal direction, and the plurality of scan signal lines 20 are parallel to each other. The gate electrode 21 is provided in at least one identification pixel, and the gate electrode 21 may be an integral structure connected to the scanning signal line 20.

In exemplary embodiments, the substrate may employ a hard substrate or a flexible substrate, such as glass or Polyimide (PI). The first metal thin film may be a metal material, such as any one or more of silver (Ag), copper (Cu), aluminum (Al), titanium (Ti), and molybdenum (Mo), or an alloy material of the above metals, such as aluminum neodymium (AlNd) alloy or molybdenum niobium (MoNb), and may have a single-layer structure or a multi-layer composite structure, such as Ti/Al/Ti, and the like.

(2) A semiconductor layer pattern is formed. In an exemplary embodiment, the forming of the semiconductor layer pattern may include: on the substrate on which the aforementioned patterns are formed, a first insulating film and a semiconductor film are sequentially deposited, and the semiconductor film is patterned by a patterning process to form a first insulating layer 11 covering the first conductive layer pattern, and a semiconductor layer pattern disposed on the first insulating layer 11, the semiconductor layer pattern including at least an active layer 22, as shown in fig. 5 and 6, and fig. 6 is a cross-sectional view taken along a-a direction in fig. 5.

In an exemplary embodiment, the active layer 22 is disposed in at least one of the identification pixels, and there is an overlapping region where an orthographic projection of the active layer 22 on the substrate and an orthographic projection of the gate electrode 21 on the substrate overlap.

In an exemplary embodiment, the semiconductor thin film may employ amorphous indium gallium zinc Oxide material (a-IGZO), zinc oxynitride (ZnON), Indium Zinc Tin Oxide (IZTO), amorphous silicon (a-Si), polycrystalline silicon (p-Si), hexathiophene or polythiophene, etc., that is, the present disclosure is applicable to a transistor manufactured based on Oxide (Oxide) technology, silicon technology or organic technology. The first insulating layer may be any one or more of silicon oxide (SiOx), silicon nitride (SiNx), and silicon oxynitride (SiON), and may be a single layer, a multilayer, or a composite layer, and is referred to as a Gate Insulating (GI) layer.

(3) Forming a second conductive layer pattern. In an exemplary embodiment, the forming of the second conductive layer pattern may include: a second metal film is deposited on the substrate on which the aforementioned pattern is formed, and the second metal film is patterned through a patterning process to form a second conductive layer pattern, the second conductive layer including the data signal line 30, the source electrode 23, the drain electrode 24, and the first electrode 31, as shown in fig. 7 and 8, and fig. 8 is a cross-sectional view taken along a-a direction in fig. 7.

In an exemplary embodiment, the data signal lines 30 extend in a vertical direction, and the plurality of data signal lines 30 are parallel to each other. The plurality of scanning signal lines 20 extending in the horizontal direction and the plurality of data signal lines 30 extending in the vertical direction intersect with each other to define a plurality of identification pixels arranged in a matrix.

In an exemplary embodiment, the source electrode 23, the drain electrode 24, and the first electrode 31 are disposed within at least one recognition pixel, the source electrode 23 may be a unitary structure connected to the data signal line 30, the drain electrode 24 is disposed opposite to the source electrode 23, the active layer between the source electrode 23 and the drain electrode 24 forms a channel region, and the first electrode 31 is connected to the drain electrode 24.

In an exemplary embodiment, the drain electrode 24 and the first electrode 31 may be a unitary structure, i.e., the drain electrode of the thin film transistor simultaneously serves as the cathode of the PIN junction photodiode.

In an exemplary embodiment, the second metal thin film may employ a metal material, such as any one or more of silver (Ag), copper (Cu), aluminum (Al), titanium (Ti), and molybdenum (Mo), or an alloy material of the above metals, such as aluminum neodymium alloy (AlNd) or molybdenum niobium alloy (MoNb), and may be a single-layer structure, or a multi-layer composite structure, such as Ti/Al/Ti, and the like.

To this end, a Thin Film Transistor (TFT) as a switching device in a fingerprint recognition substrate is formed on a base substrate, and the Thin Film Transistor includes a gate electrode 21, an active layer 22, a source electrode 23, and a drain electrode 24.

(4) A second insulating layer pattern is formed. In an exemplary embodiment, the forming of the second insulation layer pattern may include: depositing a second insulating film on the substrate on which the patterns are formed, patterning the second insulating film through a patterning process to form a second insulating layer 12 covering the second conductive layer pattern, wherein a first via hole V1 is formed in the second insulating layer 12, the first via hole V1 is located in a region where the first electrode 31 is located, the second insulating layer 12 in the first via hole V1 is etched away to expose a surface of the first electrode 31, as shown in fig. 9 and 10, and fig. 10 is a cross-sectional view taken along a direction of a-a in fig. 9.

(5) And forming a photoelectric conversion layer pattern. In an exemplary embodiment, forming the photoelectric conversion layer pattern may include: on the substrate on which the foregoing pattern is formed, a photoelectric conversion film is deposited, and the photoelectric conversion film is patterned by a patterning process to form a pattern of the photoelectric conversion layer 32, and the photoelectric conversion layer 32 is disposed on the first electrode 31 within the first via hole V1 and connected to the first electrode 31, as shown in fig. 11 and 12, and fig. 12 is a cross-sectional view taken along a-a direction in fig. 11.

In an exemplary embodiment, the photoelectric conversion layer 32 includes a first doped layer, an intrinsic layer, and a second doped layer stacked as a main structure of the photodiode. The first doping layer can adopt P-type doped amorphous silicon (a-Si) or polysilicon (P-Si), and the second doping layer can adopt N-type doped amorphous silicon or polysilicon; or alternatively. The first doping layer can adopt amorphous silicon or polysilicon doped with N type, and the second doping layer can adopt amorphous silicon or polysilicon doped with P type.

In an exemplary embodiment, there is no overlapping area of the orthographic projection of the photoelectric conversion layer 32 on the substrate and the orthographic projection of the thin film transistor on the substrate.

(6) A planarization layer and a third insulation layer pattern are formed. In an exemplary embodiment, the forming of the planarization layer and the third insulation layer pattern may include: on the substrate on which the aforementioned pattern is formed, a flat film is coated, then a third insulating film is deposited, and the third insulating film and the flat film are patterned by a patterning process to form a flat layer 13 covering the second insulating layer 12 and the photoelectric conversion layer 32 and a third insulating layer 14 disposed on the flat layer 13, a second via hole V2 is disposed on the third insulating layer 14 and the flat layer 13, the second via hole V2 is located in a region where the photoelectric conversion layer 32 is located, the third insulating layer 14 and the flat layer 13 in the second via hole V2 are removed, and a surface of the photoelectric conversion layer 32 is exposed, as shown in fig. 13 and 14, fig. 14 is a cross-sectional view taken along a-a direction in fig. 13.

In an exemplary embodiment, the planarization layer 13 is used to planarize a film height difference caused by the photoelectric conversion layer 32, so as to avoid a process defect caused by excessive climbing of a subsequent film during a deposition process.

In an exemplary embodiment, the planarization layer may employ a resin material, and the third insulating layer may employ any one or more of silicon oxide (SiOx), silicon nitride (SiNx), and silicon oxynitride (SiON), which may be a single layer, a multi-layer, or a composite layer.

(7) Forming a second electrode pattern. In an exemplary embodiment, the forming of the second electrode pattern may include: on the substrate on which the foregoing pattern is formed, a transparent conductive film is deposited, the transparent conductive film is patterned through a patterning process, a pattern of a second electrode 33 is formed on the third insulating layer 14, the second electrode 33 is connected to the positive electrode of the photoelectric conversion layer 32 through a second via hole V2, as shown in fig. 15 and 16, and fig. 16 is a sectional view taken along a-a direction in fig. 15.

In an exemplary embodiment, the transparent conductive material may employ Indium Tin Oxide (ITO) or Indium Zinc Oxide (IZO).

To this end, a photodiode (Photo-Diode) as a photosensitive device in a fingerprint recognition substrate is formed on a base, and the PIN type photodiode includes a first electrode 31, a photoelectric conversion layer 32, and a second electrode 33, and is used to photoelectrically convert incident light. In an exemplary embodiment, a fingerprint sensing layer including a thin film transistor as a switching device and a PIN type photodiode as a light sensing device together constituting a fingerprint recognition substrate, the thin film transistor controls readout of an electrical signal in the photodiode.

In an exemplary embodiment, the substrate has a thickness of about 120 μm to about 150 μm, and the fingerprint sensing layer has a thickness of about 3 μm to about 5 μm.

(8) A power line pattern is formed. In an exemplary embodiment, forming the power line pattern may include: on the substrate on which the aforementioned pattern is formed, a third metal film is deposited, and the third metal film is patterned by a patterning process, and a power line 34 pattern is formed on the second electrode 33, as shown in fig. 17 and 18, and fig. 18 is a cross-sectional view taken along a-a direction in fig. 17.

In the exemplary embodiment, the power line 34 is directly connected to the second electrode 33, and the bias voltage provided by the power line 34 is transmitted to the second electrode 33. Since the second electrode 33 is made of transparent conductive material and has a relatively high resistivity, the power line 34 having a relatively low resistivity provides a bias voltage to ensure that each identification pixel of the fingerprint identification substrate has a uniform bias voltage, thereby ensuring the uniformity of the identification performance of the fingerprint identification substrate.

In an exemplary embodiment, the orthographic projection of the power supply line 34 on the substrate includes the orthographic projection of the active layer channel region on the substrate. The power line 34 is opaque and thus can serve as a light shielding layer to prevent the channel region of the thin film transistor from generating a large leakage current when being illuminated, thereby ensuring the electrical performance of the thin film transistor.

In an exemplary embodiment, the third metal thin film may employ a metal material, such as any one or more of silver (Ag), copper (Cu), aluminum (Al), titanium (Ti), and molybdenum (Mo), or an alloy material of the above metals, such as aluminum neodymium alloy (AlNd) or molybdenum niobium alloy (MoNb), and may have a single-layer structure, or a multi-layer composite structure, such as Ti/Al/Ti, and the like.

(9) And forming a light hole layer pattern. In an exemplary embodiment, forming the light hole layer pattern may include: on the substrate on which the foregoing pattern is formed, a light hole film is coated, the light hole film is patterned by a patterning process, a light hole Layer (Aperture Layer)41 pattern is formed on the second electrode 33 in the second via hole, the light hole Layer 41 includes a plurality of light holes V3, the light hole film in the light holes is removed to expose the surface of the second electrode 33, as shown in fig. 19 and 20, and fig. 20 is a sectional view taken along a-a in fig. 19.

In an exemplary embodiment, the light hole layer 41 is used to form a light transmission channel that can restrict the light path of light rays converged by the lens, and restrict large-angle oblique light rays from being irradiated onto the photodiode, thereby reducing crosstalk.

In an exemplary embodiment, the aperture layer 41 may be made of black organic photosensitive material with high absorptivity, such as photosensitive acrylic resin or photosensitive polyester. The thickness of the aperture layer 41 may be about 5 μm to about 10 μm and the aperture of the aperture V3 may be about 3 μm to about 8 μm, so as to restrict light within a certain angle from being incident on the photodiode of the fingerprint sensing layer.

Note that the configuration shown in fig. 19 and 20 only illustrates 3 × 4 photo apertures, but actually, the photo aperture of each identification pixel may be an array of several tens or hundreds of photo apertures, and the cross-sectional shape of the photo aperture in a plane parallel to the display substrate may be circular, elliptical, polygonal, or the like.

(10) A light modulation layer pattern is formed. In an exemplary embodiment, forming the light modulation layer pattern may include: a light modulation film is coated on the substrate on which the above-described pattern is formed, and the light modulation film is patterned by a patterning process to form a pattern of the light modulation layer 42, as shown in fig. 21 and 22, and fig. 22 is a sectional view taken along a-a direction in fig. 21.

In an exemplary embodiment, the light modulation layer 42 may not only provide a good plane for a subsequently formed lens layer, but also may effectively cut off externally incident infrared light and may adjust the thickness such that the focal point of each lens is located at the midpoint of the depth of the light aperture.

(11) Forming a lens layer pattern. In an exemplary embodiment, the forming of the lens layer pattern may include: on the substrate on which the aforementioned pattern is formed, a lens film is coated, and the lens film is patterned by a patterning process to form a lens layer 43 pattern, as shown in fig. 1 and 2.

In an exemplary embodiment, the lens layer 43 includes a plurality of microlenses constituting a Microlens Array (Microlens Array) for condensing reflected light of the fingerprint to perform a light collecting function.

In an exemplary embodiment, the microlenses have a convex structure, and the focal point of at least one microlens is on the axis of at least one light aperture (or the center line of the light channel) in the direction perpendicular to the substrate. In an exemplary embodiment, the light aperture may confine light within a range of ± θ 2, i.e., light within a range of ± θ 2 from a normal of a plane in which the lens layer is located may reach the photodiode of the fingerprint sensing layer. The light hole and the micro lens are combined to restrain the light rays within the range of +/-theta 1, and theta 1 is less than theta 2. In an exemplary embodiment, θ 1 may be about 5 ° to 15 °.

In an exemplary embodiment, a high-transmittance resin material or the like may be used as the material of the lens layer 43, and the thickness is about 5 μm to 10 μm.

In an exemplary embodiment, the lens layer 43 may be implemented by a process of Laser Direct Writing (Laser Direct Writing), nanoimprinting (Nanolithography), Resist Reflow (Resist Reflow), and the like.

In an exemplary embodiment, the light modulation layer may employ an infrared cut material for cutting off infrared light rays to prevent external light rays from interfering with normal fingerprint imaging on the one hand, and for providing the lenses with a proper focal length such that the focal point of each lens is located at the midpoint of the depth of the optical aperture on the other hand. The fingerprint identification substrate is provided with the strong light prevention function by arranging the light modulation layer, and the focal length of the lens is adjusted.

In an exemplary embodiment, the light modulation layer may be a reflective light modulation layer, and the reflective light modulation layer may include a plurality of first sub-layers and a plurality of second sub-layers, the first sub-layers having a refractive index different from that of the second sub-layers, the first sub-layers and the second sub-layers being alternately arranged to form the reflective light modulation layer in a stacked structure. For example, the material of the first sub-layer may be silicon oxide, and the material of the second sub-layer may be titanium oxide.

In an exemplary embodiment, the thickness of the reflective light modulation layer may be about 30 μm to 50 μm, and the actual thickness may be determined according to the focal length of the lens.

To this end, a collimating filter structure layer including a photo-aperture layer, a light modulation layer and a lens layer is prepared, and the thickness of the collimating filter structure layer may be about 40 μm to 70 μm.

Fig. 23 is a transmittance curve of a reflective light modulation layer according to an exemplary embodiment of the present disclosure. As shown in fig. 23, at a wavelength of about 600nm, the reflective light modulation layer starts to be cut off, has a low transmittance, and can effectively reflect external infrared light, so that optical signal crosstalk caused by the infrared light entering the light hole is avoided, and the requirement of the current under-screen fingerprint product on strong light prevention can be met.

In an exemplary embodiment, the light modulation layer may be an absorption type light modulation layer, and the absorption type light modulation layer may employ a photosensitive resin having a high transmittance in a blue-green band and a low transmittance in an infrared band. For example, a cyan photosensitive acrylic resin or the like can be used for the absorption-type light modulation layer.

In an exemplary embodiment, the thickness of the absorption type light modulation layer may be about 30 μm to 50 μm, and the actual thickness may be determined according to the focal length of the lens.

Fig. 24 is a transmittance curve of an absorption-type light modulation layer according to an exemplary embodiment of the present disclosure. As shown in fig. 24, at a wavelength of about 600nm, the absorption-type light modulation layer starts to be cut off, has a low transmittance, and can effectively absorb external infrared light, so that optical signal crosstalk caused by the infrared light entering the light hole is avoided, and the requirement of the current under-screen fingerprint product on strong light prevention can be met.

It should be noted that the foregoing description is only an example of preparing the fingerprint identification substrate, and the disclosure is not limited thereto. In actual implementation, the preparation process can be adjusted according to actual needs.

As can be seen from the structure and the preparation flow of the fingerprint identification substrate described above, the fingerprint identification substrate provided by the exemplary embodiment of the present disclosure forms a collimating and filtering structure layer including a light aperture layer, a light modulation layer and a lens layer by integrating a collimating and filtering function together, and realizes an anti-glare function and a function of adjusting a focal length of a lens by using the light modulation layer between the light aperture layer and the lens layer, thereby effectively reducing the thickness of the collimating and filtering structure. According to the fingerprint identification substrate of the exemplary embodiment of the disclosure, the collimating light path filtering structure is directly prepared on the fingerprint sensing layer, so that the overall thickness of the fingerprint identification substrate is effectively reduced, the development trend of lightness and thinness is met, the alignment precision in preparation is improved, and the product quality is improved. Compared with the stacking structure of optical cement, a filter film, optical cement and a collimation light path film adopted in the prior art, the whole thickness of the fingerprint identification substrate in the exemplary embodiment of the disclosure is about 160-220 μm, the whole thickness is reduced by about 30-40%, the space occupied by the fingerprint identification substrate inside the display device is effectively reduced, the interference to the internal structure of the display device is reduced, and the fingerprint identification substrate has a good application prospect. The fingerprint identification substrate provided by the disclosure greatly simplifies the process procedure through high integration of functions, and the preparation process can be well compatible with the existing preparation process, and is simple in process implementation, easy to implement, high in production efficiency, low in production cost and high in yield.

The present disclosure also provides a display device including the fingerprint recognition substrate of the foregoing exemplary embodiment. In an exemplary embodiment, the display device may include a fingerprint identification substrate and an Organic Light-Emitting Diode (OLED) display substrate, wherein the fingerprint identification substrate is attached to a back surface of the OLED display substrate through an optical adhesive, that is, the OLED display substrate is disposed on one side of a lens layer of the fingerprint identification substrate. In an exemplary embodiment, the display device includes a plurality of display pixels, each of which is disposed in one-to-one correspondence with each of the identification pixels in a direction perpendicular to the substrate. When the fingerprint identification device works, the OLED is used as a light source to emit light to a fingerprint, and the reflection intensity of the fingerprint valley/ridge to the light is different, so that the intensity of the light emitted to the fingerprint identification substrate is different, and the lines of the fingerprint are distinguished accordingly.

In an exemplary embodiment, the display device may be: any product or component with a display function, such as a mobile phone, a tablet computer, a television, a display, a notebook computer, a digital photo frame, and a navigator, but the disclosure is not limited thereto.

The present disclosure also provides a method for manufacturing a fingerprint identification substrate, which is used to manufacture the fingerprint identification substrate of the foregoing exemplary embodiment. In an exemplary embodiment, a method of manufacturing a fingerprint identification substrate may include:

forming a fingerprint sensing layer on a substrate;

forming a light modulation layer on the aperture layer;

In an exemplary embodiment, the light modulation layer includes a reflective light modulation layer including at least one first sub-layer and a second sub-layer alternately arranged, the first sub-layer having a refractive index different from that of the second sub-layer.

In an exemplary embodiment, the light modulation layer includes an absorption type light modulation layer including a cyan photosensitive acrylic resin.

The specific content of the method for manufacturing a fingerprint identification substrate according to the present disclosure has been described in detail in the foregoing fingerprint identification substrate manufacturing process, and is not described herein again.

The utility model provides a preparation method of fingerprint identification base plate through being integrated as collimation light filtering structure layer with light aperture layer, light modulation layer and lens layer, sets up the light modulation layer between light aperture layer and lens layer both to be used for cutting off outside infrared ray, is arranged in the focus of lens in the adjustment lens layer again, has effectively reduced the thickness of fingerprint identification base plate, has effectively solved the great problem of current fingerprint identification module thickness. According to the preparation method of the fingerprint identification substrate, the process is greatly simplified through high integration of functions, the preparation process can be well compatible with the existing preparation process, the process is simple to implement, easy to implement, high in production efficiency, low in production cost and high in yield.

Although the embodiments disclosed in the present disclosure are described above, the descriptions are only for the convenience of understanding the present disclosure, and are not intended to limit the present disclosure. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure, and that the scope of the present disclosure is to be limited only by the terms of the appended claims.

Claims

1. The utility model provides a fingerprint identification base plate, its characterized in that is in including basement, setting fingerprint sensing layer on the basement is kept away from with setting up at fingerprint sensing layer the collimation filter structure layer of basement one side, collimation filter structure layer includes along keeping away from the basement direction photoelectricity layer, light modulation layer and the lens layer that set gradually, light modulation layer is used for adjusting the focus on lens layer and infrared light cut off.

2. The fingerprint identification substrate of claim 1, wherein the fingerprint sensing layer comprises a thin film transistor and a photodiode disposed on the base; the thin film transistor includes a gate electrode, an active layer, a source electrode, and a drain electrode, and the photodiode includes a first electrode, a photoelectric conversion layer, and a second electrode; the drain electrode of the thin film transistor and the first electrode of the photodiode are arranged on the same layer.

3. The fingerprint identification substrate of claim 2, wherein the fingerprint sensing layer further comprises a second insulating layer disposed on a side of the thin film transistor away from the substrate, the second insulating layer is provided with a first via hole exposing the first electrode, and the photoelectric conversion layer is connected to the first electrode through the first via hole.

4. The fingerprint identification substrate of claim 3, wherein the fingerprint sensing layer further comprises a flat layer and a third insulating layer disposed on a side of the second insulating layer away from the base, the flat layer and the third insulating layer are provided with a second via hole exposing the photoelectric conversion layer, and the second electrode is disposed on the third insulating layer and connected to the photoelectric conversion layer through the second via hole.

5. The fingerprint identification substrate of claim 4, wherein the fingerprint sensing layer further comprises a power line disposed on a side of the second electrode away from the substrate, and an orthographic projection of the power line on the substrate comprises an orthographic projection of a channel region of the thin film transistor on the substrate.

6. The fingerprint identification substrate of claim 2, wherein the aperture layer is disposed on a side of the second electrode away from the substrate, the aperture layer including at least one aperture forming a light transmission channel.

7. The fingerprint identification substrate of claim 6, wherein the thickness of the aperture layer is 5 μm to 10 μm, and the aperture of the aperture is 3 μm to 8 μm.

8. The substrate of claim 6, wherein the lens layer is disposed on a side of the light modulation layer away from the base, the lens layer comprising at least one lens, a focal point of the at least one lens being located on an axis of the at least one light aperture.

9. The substrate of claim 8, wherein the lens layer has a thickness of 5 μm to 10 μm.

10. The substrate according to any one of claims 1 to 9, wherein the light modulation layer comprises a reflective light modulation layer including at least one first sub-layer and a second sub-layer alternately arranged, the first sub-layer having a refractive index different from that of the second sub-layer, and the reflective light modulation layer has a thickness of 30 μm to 50 μm.

11. The substrate according to any one of claims 1 to 9, wherein the light modulation layer comprises an absorption type light modulation layer, the absorption type light modulation layer comprises a cyan photosensitive acrylic resin, and the thickness of the absorption type light modulation layer is 30 μm to 50 μm.

12. A display device comprising the fingerprint identification substrate according to any one of claims 1 to 11.

13. A preparation method of a fingerprint identification substrate is characterized by comprising the following steps:

forming a fingerprint sensing layer on a substrate;

14. The method of claim 13, wherein forming a collimating filter structure layer on the fingerprint sensing layer comprises:

forming a light modulation layer on the aperture layer;

15. The method of claim 14,

the light modulation layer includes a reflective light modulation layer including at least one first sublayer and a second sublayer alternately arranged, a refractive index of the first sublayer being different from a refractive index of the second sublayer; alternatively, the first and second electrodes may be,