TWI652837B - Sensing device - Google Patents

Abstract

A sensing device includes an array substrate, a protective layer, and a backlight module. The array substrate includes a substrate and has a plurality of sensing units, wherein the sensing unit includes an active element, a photosensitive element, and at least one light transmitting region. The active device is disposed on the substrate. The photosensitive element is disposed on the substrate and is electrically connected to the active element. The light-transmitting area is located around the photosensitive element. The protection layer is disposed on the array substrate. The protection layer has a plurality of grooves. The grooves are arranged close to the array substrate. Each groove overlaps the photosensitive element of the sensing unit in the normal direction of the substrate. The backlight module is disposed on the other side of the array substrate opposite to the protective layer.

Description

Sensing device

This disclosure relates to a sensing device, and more particularly to a light sensing device.

Fingerprint identification is a widely used biometric technology. Its principle is to determine the identity of the owner of the fingerprint by collecting fingerprint images and then using the identification software to extract and compare the characteristic information of the fingerprint. At present, many products have integrated fingerprint recognition functions, such as notebook computers and mobile phones. Since everyone's fingerprint is different, it can be used as a security mechanism to identify the user.

A general thin film transistor (TFT) backlight sensing device includes an array substrate. The array substrate includes an active element (such as a TFT) and a photosensitive element. When the finger covers the sensing device, the backlight provided by the backlight module will be irradiated on the finger, and the reflection light will be reflected to the photosensitive element in the active element array substrate through the reflection of the fingerprint path (peak and trough) of the hand. At this time, the reflected light is absorbed by the photosensitive element to generate a photocurrent. Then, the external integrator converts the detected photocurrent to current and voltage. Finally, the output voltage signal undergoes analog-to-digital conversion and appropriate image processing steps, thereby producing grayscale differences and completing fingerprint identification.

However, the thickness of the protective layer (such as glass) disposed above the sensing device makes the photosensitive element easily receive the scattered light generated by the adjacent fingerprint, which makes the image contrast worse, which causes problems such as image blur. However, reducing the thickness of the protective layer also deteriorates the durability of the protective layer. Therefore, an improved structure is needed to overcome the above problems.

One embodiment of the present disclosure is a sensing device including an array substrate, a protective layer, and a backlight module. The array substrate includes a base plate and has a plurality of sensing units, wherein the sensing unit includes an active element, a photosensitive element, and at least one light transmitting region. The active device is disposed on the substrate. The photosensitive element is disposed on the substrate and is electrically connected to the active element. The light-transmitting area is located around the photosensitive element. The protection layer is disposed on the array substrate. The protection layer has a plurality of grooves. The grooves are arranged close to the array substrate. Each groove overlaps the photosensitive element of the sensing unit in the normal direction of the substrate. The backlight module is disposed on the other side of the array substrate opposite to the protective layer.

In the present disclosure, by designing a groove in the protective layer, the position of the groove corresponds to the photosensitive element in the array substrate, and the refractive index of the medium in the groove is smaller than that of the protective layer. Through the design of the groove, the light from a distant incident angle with a large incident angle can be totally reflected, thereby filtering out the light with a large distant angle, so that the image quality received by the photosensitive element can be improved. Therefore, according to the configuration disclosed in this disclosure, the protective layer can not only be designed with sufficient thickness to achieve the requirement of high protection, but also can obtain high-quality images through the design of the groove.

5, 6‧‧‧ sensing device

10‧‧‧Array substrate

10A‧‧‧Sensing area

10B‧‧‧Peripheral area

20, 21‧‧‧ protective layer

21A‧‧‧Part I

21B‧‧‧Part Two

30‧‧‧ backlight module

40‧‧‧Frame glue

110‧‧‧ substrate

111, 114, 118‧‧‧ metal layers

112‧‧‧Gate insulation

113‧‧‧Semiconductor layer

114A‧‧‧Lower electrode

115‧‧‧ Dielectric layer

115O‧‧‧Open

116‧‧‧Photosensitive layer

117‧‧‧ transparent electrode layer

119‧‧‧ flat layer

120‧‧‧active element

130, 130A, 130B, 130C‧‧‧

140A, 140B, 140C‧‧‧Translucent area

200, 200A, 220‧‧‧ groove

210, 230‧‧‧ media

1191‧‧‧ Top surface

2001‧‧‧ curved surface

A-A’-A ”-A '' '‧‧‧line segment

D‧‧‧ Drain

DL‧‧‧Data Line

G‧‧‧Gate

GL‧‧‧Gate line

I1, I2, I3‧‧‧‧ incident light

K‧‧‧ Detecting objects

L-L‧‧‧line segment

O‧‧‧Curvature Center

P, P1, P2, P3‧‧‧ sensing units

R‧‧‧ radius of curvature

R1, R2, R3‧‧‧ reflected light

S‧‧‧Source

T1, T2, T3‧‧‧thickness

θ ₁ , θ ₂ ‧‧‧ incident angle

Read the following detailed description and the corresponding drawings to understand the various aspects of this disclosure. It should be noted that according to standard practice in the industry, multiple features are not drawn to scale. In fact, the dimensions of multiple features can be arbitrarily increased or decreased to facilitate clarity of discussion.

FIG. 1 is a schematic top view of a sensing device according to some embodiments of the disclosure.

FIG. 2A is a partially enlarged top view of a sensing device according to some embodiments of the disclosure.

FIG. 2B is a schematic cross-sectional view of a sensing device according to some embodiments of the disclosure.

FIG. 3 is an operation principle diagram of a sensing device according to some embodiments of the disclosure.

4A to 4C are schematic cross-sectional views of the sensing device in different manufacturing steps in some embodiments of the disclosure.

FIG. 5 is a schematic cross-sectional view of a sensing device according to some embodiments of the disclosure.

6A to 6C are schematic cross-sectional views of the sensing device in different manufacturing steps in some embodiments of the disclosure.

The following disclosure provides many different embodiments or examples for implementing the different features of the main content provided in this case. The components and configurations of a specific example are described below to simplify this disclosure. Of course, this example is only illustrative and is not intended to be limiting. For example, the following description "the first feature is formed on or above the second feature", in the embodiment may include the first feature and the second feature in direct contact, and may also be included in the first feature and the second feature Additional features are formed between the first feature and the second feature without direct contact. In addition, this disclosure can be used in various examples Reuse component symbols and / or letters. The purpose of this repetition is to simplify and clarify, and does not itself define the relationship between the embodiments and / or configurations discussed.

In addition, spatially relative terms such as "beneath", "below", "lower", "above", "upper", etc. are used herein to simplify the description To describe the relationship between one element or feature and another element or feature as illustrated in the drawings. In addition to the orientation depicted, spatial relative terms also include the different orientations of an element in use or operation. This device can be oriented in other ways (rotated 90 degrees or at other orientations), and the spatially relative descriptors used in this case can be interpreted accordingly.

FIG. 1 is a schematic top view of a sensing device according to some embodiments of the disclosure. The sensing device 5 includes an array substrate 10. The array substrate 10 is provided with a plurality of data lines DL and a plurality of gate lines GL. The data lines DL and the gate lines GL are staggered with each other to form a plurality of sensing units P. In other words, the range of any sensing unit P is defined by any two adjacent data lines DL and any two adjacent gate lines GL. In some embodiments, the data line DL may also be referred to as a first signal line, and the gate line GL may also be referred to as a second signal line. Each sensing unit P is configured with an active element 120 and a photosensitive element 130, wherein the active element 120 and the photosensitive element 130 are electrically connected to each other.

In some embodiments, the active device 120 may be a thin film transistor (TFT). The active device 120 in each sensing unit P includes a gate G, a source S, and a drain D. The gate electrode G is electrically connected to the gate line GL, the source electrode S is electrically connected to the data line DL, and the drain electrode D is connected to the photosensitive element. 130 electrically connected. The detailed operation principle will be explained later.

Generally speaking, the plurality of sensing units P formed alternately between the data line DL and the gate line GL can be regarded as the sensing area 10A of the array substrate 10. On the other hand, a portion located at the periphery of the sensing region 10A can be regarded as a peripheral region 10B of the array substrate 10. The sensing area 10A is defined by a plurality of sensing units P having an active element 120 and a photosensitive element 130. In other words, the peripheral area 10B may also be referred to as a non-sensing area.

FIG. 2A is a partially enlarged top view of a sensing device according to some embodiments of the disclosure. FIG. 2B is a schematic cross-sectional view of a sensing device according to some embodiments of the disclosure. FIG. 2A and FIG. 2B show a schematic structural diagram of the sensing device 5 as shown in FIG. 1, where FIG. 2B is a cross-section along the line segment A-A′-A ”-A” ′ of FIG. 2A Illustration. It should be noted that, for the convenience of explanation, FIG. 2A and FIG. 2B only show the structure of a single sensing unit on the array substrate. In addition, for the convenience of viewing, some of the components in Figure 2B are not shown in Figure 2A, which will be described together.

The sensing device 5 includes an array substrate 10, a protective layer 20, and a backlight module 30. The protective layer 20 is disposed above the array substrate 10, and the backlight module 30 is disposed on a side of the array substrate 10 opposite to the protective layer 20. In other words, the array substrate 10 is located between the protective layer 20 and the backlight module 30.

The array substrate 10 includes a substrate 110. In some embodiments, the substrate 110 may be glass, quartz, plastic, or other suitable transparent materials.

The patterned metal layer 111 is formed on the substrate 110. The patterned metal layer 111 includes a gate line GL, a gate G of the active device 120 to be formed later, and an auxiliary electrode 111A which can be used as an auxiliary capacitor later. Patterned metal layer 111 The material may include, but is not limited to, titanium (Ti), aluminum (Al), tungsten (W), molybdenum (Mo), tantalum (Ta), copper (Cu), copper alloy, or a combination thereof.

The gate insulating layer 112 is formed on the substrate 110 and covers the patterned metal layer 111. In some embodiments, the material of the gate insulating layer 112 may be an inorganic material (for example, silicon oxide, silicon nitride, silicon oxynitride, or a stacked layer of at least two materials mentioned above), an organic material, or a combination thereof. It should be noted that the gate insulating layer 112 is not shown in FIG. 2A.

The semiconductor layer 113 is formed over the gate insulating layer 112. The semiconductor layer 113 serves as a channel region of the active device 120 to be formed later. In addition, the semiconductor layer 113 overlaps the gate G of the active device 120 in the normal direction of the substrate 110. In some embodiments, the semiconductor layer 113 may be amorphous silicon, polycrystalline silicon, an oxide semiconductor material, or other suitable semiconductor materials. In addition, in order to improve the electrical property between the subsequently formed source / drain and the semiconductor layer 113 to reduce the probability of electron tunneling and avoid short-channel effects, in some embodiments, after forming the semiconductor layer 113, Continue to form a doped amorphous silicon layer 113A (such as n-type doped) on the semiconductor layer 113, as shown in FIG. 2B.

The patterned metal layer 114 is formed over the substrate 110. The patterned metal layer 114 includes a data line DL, a source S and a drain D of the active device 120 to be formed later, and a lower electrode 114A. The source S and the drain D are electrically connected to the semiconductor layer 113. On the other hand, the lower electrode 114A and the drain electrode D are electrically connected to each other, as shown in FIG. 2A. The material of the patterned metal layer 114 may include titanium (Ti), aluminum (Al), tungsten (W), molybdenum (Mo), tantalum (Ta), copper (Cu), copper alloy, or a combination thereof, but is not limited thereto. Limited.

A dielectric layer 115 is formed over the substrate 110 and covers a metal layer 114. The dielectric layer 115 has an opening 115O, wherein the opening 115O exposes the lower electrode 114A. In some embodiments, the dielectric layer 115 may be an inorganic material (for example, silicon oxide, silicon nitride, silicon oxynitride, other suitable materials, or a combination thereof), an organic material (for example, photoresist, polyimide). (polyimide, PI), benzocyclobutene (BCB), epoxy resin (Epoxy), perfluorocyclobutane (PFCB), other suitable materials or combinations thereof), other suitable materials or combinations thereof.

The photosensitive layer 116 is formed in the opening 115O of the dielectric layer 115 and is electrically connected to the lower electrode 114A. Generally speaking, the size of the photosensitive layer 116 defines a region of the photosensitive element 130. In addition, the area of the photosensitive layer 116 is substantially smaller than that of the lower electrode 114A. In some embodiments, the material of the photosensitive layer 116 is a silicon-rich oxide (SRO). However, the present invention is not limited thereto. In other embodiments, the photosensitive layer 116 may be, for example, a PIN photodiode. , Amorphous silicon (a-Si) layers, and so on.

A transparent electrode layer 117 is formed over the dielectric layer 115 and covers the photosensitive layer 116. The photosensitive layer 116 is electrically connected to the transparent electrode layer 117. In some embodiments, the transparent electrode layer 117 includes metal oxides such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc aluminum oxide (AZO), indium aluminum oxide (AIO), indium oxide (InO), and oxide. Gallium oxide (GaO), nano carbon tubes, nano silver particles, metals or alloys, organic transparent conductive materials, or other suitable transparent conductive materials.

The patterned metal layer 118 is formed over the transparent electrode layer 117. The patterned metal layer 118 overlaps the semiconductor layer 113 in a normal direction of the substrate 110. In some embodiments, the patterned metal layer 118 is used as a light-shielding pattern. The material of the patterned metal layer 118 may include titanium (Ti), aluminum (Al), tungsten (W), molybdenum (Mo), Tantalum (Ta), copper (Cu), copper alloy, or a combination thereof, but not limited thereto.

The flat layer 119 is formed above the substrate 110 and covers the elements below. The planarization layer 119 provides a substantially planar upper surface 1191 and can be used to protect the underlying material. In some embodiments, the flat layer 119 may be a single-layer or multi-layer structure, and its material may include an inorganic insulating material (for example, silicon oxide, silicon nitride, silicon oxynitride, or other suitable insulating materials), organic Insulation materials (such as colorless / colored photoresist, polyimide, polyester, benzocyclobutene (BCB), polymethylmethacrylate (PMMA), poly (4-vinylphenol ), PVP), polyvinyl alcohol (PVA), polytetrafluoroethene (PTFE), or other suitable organic insulating materials), or other suitable insulating materials, but not limited thereto.

So far, the active element 120 and the photosensitive element 130 are generally completed. The active device 120 includes a gate G, a source S, and a drain D. The photosensitive element 130 includes a lower electrode 114A and a photosensitive layer 116. The lower electrode 114A is electrically connected to the drain electrode D (as shown in FIG. 2A).

In addition, the periphery of the photosensitive element 130 has light-transmitting regions 140A, 140B, and 140C. The light-transmitting regions 140A, 140B, and 140C substantially surround the photosensitive element 130. The light-transmitting regions 140A to 140C are defined by the patterned metal layer 114 and the patterned metal layer 111. Since the patterned metal layer 114 and the patterned metal layer 111 are generally metal materials having a light-shielding property, the areas not covered by the patterned metal layer 114 and the patterned metal layer 111 in the entire sensing unit are transparent. Area. For example, the light-transmitting areas 140A to 140C in FIG. 2A are generally It is defined by a region between the gate line GL, the data line DL, the lower electrode 114A, and a part of the metal layer 111. In other words, one of the light-transmitting regions 140A to 140C is located between the photosensitive element 130 and the adjacent data line DL (first signal line) or gate line GL (second signal line). In some embodiments, the light-transmitting region 140A is at least partially located between the active element 120 and the photosensitive element 130.

Specifically, when the photosensitive element 130 is irradiated with light, electron hole pairs are generated due to the characteristics of the material being excited by the incident light, and these light-induced excitations can be separated under an external bias (or external electric field) Electron hole pairs to form a photocurrent (sensing signal).

The protective layer 20 is disposed above the array substrate 10. In some embodiments, the protective layer 20 is substantially in contact with the flat layer 119. The material of the protective layer 20 may be glass or other suitable transparent materials. In some embodiments, the thickness T1 of the protective layer 20 ranges from about 10 micrometers (μm) to about 500 micrometers (μm).

In FIG. 2B, the protective layer 20 has at least one groove 200, wherein the groove 200 is disposed adjacent to the array substrate 10 and has an arc-shaped surface 2001 that faces the array substrate 10. In some embodiments, the curved surface 2001 has a radius of curvature R, wherein the radius of curvature R ranges from about 15 micrometers (μm) to about 100 micrometers (μm). The curved surface 2001 of the groove 200 has a center of curvature O. In some embodiments, the center of curvature O is located on the other side of the flat layer 119 relative to the protective layer 20. In FIG. 2A, the outline of the groove 200 of the protective layer 20 is circular (indicated by a dotted line). In other words, the vertical projection of the groove 200 on the substrate 110 is a circle, but it is not limited to this. In other embodiments, it can also be other suitable shapes, such as oval, polygon, etc.

In addition, the groove 200 is aligned with the photosensitive element in a normal direction of the substrate 110. Pieces 130 overlap. From another perspective, each of the grooves 200 of the protective layer 20 substantially corresponds to the photosensitive element 130 in a sensing unit. Viewed from the direction of the vertical substrate 110, the groove 200 may be slightly smaller than, equal to, or slightly larger than the photosensitive element 130. In some embodiments, a part of the upper surface 1191 of the flat layer 119 is close to the groove 200, so that the effect is better.

The groove 200 has a medium 210 therein, wherein the medium 210 has a refractive index n1 and the protective layer 20 has a refractive index n2. In some embodiments, the refractive index n1 is smaller than the refractive index n2. In some embodiments, the refractive index n1 ranges from about 1 to about 1.2, and the refractive index n2 ranges from about 1.35 to about 1.6. In some embodiments, the material of the medium 210 may be air or a suitable gas. In other embodiments, the medium 210 may be a vacuum. Generally speaking, the refractive index of the material of the medium 210 is smaller than the refractive index of the material of the protective layer 20 can be applied here.

The backlight module 30 may be a direct type backlight module or an edge type backlight module, depending on the actual application. There may be a gap or no gap between the backlight module 30 and the array substrate 10. In other embodiments, the backlight module 30 may also be a plurality of micro-light-emitting elements integrated in the array substrate 10, such as micro-LEDs or other suitable types of light sources. The disclosure is not limited to this. this. In some embodiments, the backlight module 30 can emit visible light, infrared light, or a combination thereof. In some embodiments, in the normal direction of the substrate 110, the protective layer 20 directly above the light-transmitting area (such as the light-transmitting areas 140A and 140B in FIG. 2B) is tightly combined with the flat layer 119 (without a gap) so that The light transmitted upward from the transparent area will not be affected by other media and will change the propagation path. In some embodiments, the vertical projection of the recess 200 on the substrate 110 does not overlap with the light-transmitting regions 140A to 140C, so as to prevent the recess 200 from affecting the propagation path of the incident light I1.

Referring to FIG. 2B, the operation principle of the sensing device 5 disclosed in the present disclosure will be described below. The backlight module 30 provides a light source in the direction of the array substrate 10, and the light source is transmitted from the light transmitting area (for example, the light transmitting areas 140A to 140C) of the array substrate 10 to the protective layer 20. After the object K to be detected (for example, a user's finger) contacts the surface of the protective layer 20, for example, the incident light I1 provided by the backlight module 30 is incident on the surface of the object K to be detected through the light transmission area 140B and Reflected, the reflected light R1 is transmitted to the corresponding photosensitive layer 116 in the photosensitive element 130. The photosensitive layers 116 of the plurality of photosensitive elements 130 generate a plurality of photocurrents after receiving the reflected light R1 generated in each area. Multiple photocurrents can be read out through the corresponding active element 120, so that the sensing device 5 can detect the K state of the object to be detected.

FIG. 3 is an operation principle diagram of a sensing device according to some embodiments of the disclosure. FIG. 3 is a schematic cross-sectional view taken along line L-L of FIG. 1. For the convenience of description, FIG. 3 only illustrates some of the component features. In FIG. 3, the array substrate 10 has a plurality of sensing units P1, P2, and P3. The sensing units P1 to P3 are defined by a plurality of data lines DL. Photosensitive elements 130A, 130B, and 130C are disposed in the sensing units P1 to P3, respectively.

The backlight module 30 provides a light source to the array substrate 10. For example, the backlight module 30 provides two incident lights I2 and I3 to the array substrate 10. When the object K to be detected (for example, a fingerprint) touches the protective layer 20, the incident light I2 and I3 are transmitted from the corresponding transparent areas toward the protective layer 20, and are incident on the object K to be detected through the protective layer 20. Reflected light R2 and R3 are generated. The incident light I2 is incident from the light-transmitting area adjacent to the photosensitive element 130A, and the incident light I3 is incident from the light-transmitting area farther from the photosensitive element 130A. Both the reflected light R2 and R3 are incident toward the photosensitive element 130A.

Before the reflected light R2 and R3 enter the photosensitive element 130A, they will first touch the groove 200A above the photosensitive element 130. As mentioned above, the medium 210 in the groove 200A has a refractive index n1, and the protective layer 20 has a refractive index n2, where n1 is smaller than n2. According to snell's law, the critical angle of total reflection θ _c = sin ^-1 (n2 / n1). Thus, when the incident light enters the interface of different materials (protective layer 20 and the turn of the medium interface 210), if the angle of incidence larger than the critical angle θ _c will be totally reflected. In some embodiments, the incident angles (the angle between the incident light and the normal of the incident surface) of the reflected light R2 and R3 in the groove 200A are θ ₁ and θ ₂ , respectively. Therefore, the incident angle θ _{2 of the} reflected light R3 is larger than the incident angle θ _{1 of the} reflected light R2. Therefore, in some embodiments, if the incident angle θ _{2 is} greater than the critical angle θ _c , the reflected light R3 will be totally reflected at the interface between the groove 200A and the medium 210, and will not be received by the photosensitive element 130A. In this way, for the photosensitive element in a single sensing unit, the reflected light from a distant place can be filtered by the design of the groove, so that the overall image quality is improved.

In practical applications, the user can adjust the thickness of the protective layer, the material of the protective layer, and the material of the medium in the groove, and then design the contour of the desired groove (such as adjusting the size and radius of curvature) to make the image To achieve a clear effect. Therefore, according to the configuration disclosed in this disclosure, the protective layer can not only be designed with sufficient thickness to achieve the requirement of high protection, but also can obtain high-quality images through the design of the groove.

4A to 4C are schematic cross-sectional views of the sensing device in different manufacturing steps in some embodiments of the disclosure.

In Fig. 4A, a protective layer 20 is provided. The material of the protective layer 20 may be It is glass or other suitable transparent materials.

In FIG. 4B, a plurality of grooves 200 are formed above the protective layer 20. As mentioned above, the contour (such as the size and the radius of curvature) of the groove 200 may vary according to actual needs, and the disclosure is not limited thereto. In some embodiments, the groove 200 may be formed by etching.

Referring to FIG. 4C, a side of the protective layer 20 having the groove 200 is bonded to the array substrate 10 so that the groove 200 is located between the protective layer 20 and the array substrate 10. In some embodiments, the protective layer 20 and the array substrate 10 can be bonded through the frame adhesive 40. The frame adhesive 40 is disposed in the peripheral region 10B of the array substrate 10, and thereby the array substrate 10 and the protective layer 20 are adhered. Since the peripheral area 10B surrounds the sensing area 10A, arranging the sealant 40 in the peripheral area 10B can prevent water vapor and foreign matter from penetrating into the groove 200 of the protective layer 20, so that the refractive index of the medium in the groove 200 changes. In other embodiments, the protective layer 20 and the array substrate 10 may be bonded by using a vacuum bonding method. That is, the protective layer 20 is bonded to the array substrate 10 in a vacuum environment. After the components are removed from the vacuum environment, the protective layer 20 and the array substrate 10 will be naturally adsorbed by the pressure of the atmosphere. In other embodiments, the above-mentioned various methods may be combined to combine the protective layer 20 and the array substrate 10.

FIG. 5 is a schematic cross-sectional view of a sensing device according to some embodiments of the disclosure. The sensing device 6 of Fig. 5 is similar to the sensing device 5 of Fig. 2B. Therefore, for simplicity, the same features will be represented by the same component symbols and will not be described again.

The sensing device 6 includes an array substrate 10, a protective layer 21, and a backlight module 30. The protective layer 21 is disposed above the array substrate 10, and the backlight module 30 is disposed on a side of the array substrate 10 opposite to the protective layer 21. In other words, the array The substrate 10 is located between the protective layer 21 and the backlight module 30.

In this embodiment, the difference from the embodiment of FIG. 2B is that the protective layer 21 is divided into a first portion 21A and a second portion 21B, where the second portion 21B is disposed between the first portion 21A and the array substrate 10, and the first portion 21A The material may be glass or other suitable transparent materials, and the material of the second part 21B may be a material with high light transmittance, such as resin. The material of the first part 21A is different from that of the second part 21B.

The second portion 21B of the protective layer 21 has at least one groove 220. The groove 220 is disposed near the array substrate 10. The structure and use of the groove 220 are the same as those of the groove 200 described in FIGS. 2B to 3, and will not be described again for simplicity. The first portion 21A has a thickness T2, and the second portion 21B has a thickness T3. Since the groove 220 is substantially located in the second portion 21B, the first portion 21A has a substantially uniform thickness T2. In addition, in some embodiments, the thickness T2 of the first portion 21A is greater than the thickness T3 of the second portion 21B. In practical applications, the user can design the desired thickness T2 of the first portion 21A to improve the protection of the protective layer 21. In some embodiments, the thickness T2 of the protective layer ranges from about 5 micrometers (μm) to about 500 micrometers (μm). The thickness T3 of the protective layer ranges from about 5 micrometers (μm) to about 30 micrometers (μm).

The groove 220 has a medium 230 therein, wherein the medium 230 has a refractive index n1, the second portion 21B of the protective layer 20 has a refractive index n2, and the first portion 20A of the protective layer has a refractive index n3. In some embodiments, the refractive index n1 is smaller than the refractive indices n2 and n3. In some embodiments, the refractive index n1 ranges from about 1 to about 1.2, and the refractive indices n2 and n3 range from about 1.35 to about 1.6. Generally speaking, the values of the refraction coefficients n2 and n3 are close to or the same, so as to avoid Refraction (even total reflection) of the incident light at large angles. In other words, the difference between the refractive indices n2 and n3 is smaller than the difference between the refractive indices n1 and n2. In some embodiments, the material of the medium 230 may be air or a suitable gas. In other embodiments, the medium 230 may be a vacuum. Generally speaking, the refractive index of the material of the medium 230 is smaller than the refractive index of the material of the second portion 21B of the protective layer 20 can be applied here.

6A to 6C are schematic cross-sectional views of the sensing device in different manufacturing steps in some embodiments of the disclosure.

In FIG. 6A, a protective layer 21 is provided. The protective layer 21 has a first portion 21A and a second portion 21B. The material of the first part 21A may be glass or other suitable transparent materials. The material of the second part 21B may be a material having a high light transmittance, such as resin. The protective layer 21 may be formed by coating a material (for example, resin) of the second portion 21B on the first portion 21A (for example, glass).

In FIG. 6B, a plurality of grooves 220 are formed above the second portion 21B of the protective layer 21. As mentioned above, the contour (such as the size and the radius of curvature) of the groove 220 may be changed according to actual needs, and the disclosure is not limited thereto. In some embodiments, the groove 220 may be formed by means of Nanoimprint Lithography (NIL). Nano-imprinting technology mainly uses a transfer method to define a desired pattern (such as the groove 220), and the desired pattern depends on the surface of the mold used for the transfer. For example, a mold having a special pattern on the surface is embossed on a target layer (such as a resin) to form a desired pattern.

In FIG. 6C, a side of the protective layer 21 having the groove 220 is bonded to the array substrate 10 so that the groove 220 is located between the protective layer 21 and the array substrate 10. In some embodiments, the protective layer 21 and the array substrate 10 can pass through the frame adhesive. 40 for bonding. The frame adhesive 40 is disposed in the peripheral region 10B of the array substrate 10, and thereby the array substrate 10 and the protective layer 21 are adhered. Since the peripheral area 10B surrounds the sensing area 10A, arranging the sealant 40 in the peripheral area 10B can prevent water vapor and foreign matter from penetrating into the groove 220 of the protective layer 21, so that the refractive index of the medium in the groove 220 changes. In other embodiments, the protective layer 21 and the array substrate 10 may be bonded by vacuum bonding. In other embodiments, the protection layer 21 and the array substrate 10 may be combined with each of the above methods.

The disclosure provides a sensing device including an array substrate, a protective layer, and a backlight module. In the present disclosure, by designing a groove in the protective layer, the position of the groove corresponds to the photosensitive element in the array substrate, and the refractive index of the medium in the groove is smaller than that of the protective layer. Through the design of the groove, the light from a distant incident angle with a large incident angle can be totally reflected, thereby filtering out the light with a large distant angle, so that the image quality received by the photosensitive element can be improved. Therefore, according to the configuration disclosed in this disclosure, the protective layer can not only be designed with sufficient thickness to achieve the requirement of high protection, but also can obtain high-quality images through the design of the groove.

The features of several embodiments are summarized above so that those skilled in the art can better understand the aspects of the present disclosure. Those skilled in the art should understand that they can easily use this disclosure as a basis to design or modify other processes and structures to achieve the same purpose and / or achieve the same advantages. Those skilled in the art should also understand that such equivalent structures do not depart from the spirit and scope of this disclosure, and that they can make various changes to this article without departing from the spirit and scope of this disclosure, Supersedes and changes.

Claims (14)

A sensing device includes: an array substrate including a substrate, the array substrate having a plurality of sensing units, wherein one of the sensing units includes: an active element disposed on the substrate; and a photosensitive element disposed on the substrate. The substrate is electrically connected to the active element; and at least one light-transmitting region is located around the photosensitive element; a protective layer is disposed on the array substrate, wherein the protective layer has a plurality of grooves and the grooves The grooves are disposed near the array substrate, and each of the grooves overlaps with the photosensitive elements of the sensing units in a normal direction of the substrate, wherein each of the grooves has an arc-shaped surface, and the arc-shaped surface has an A curvature radius and a curvature center, the curvature center is located below the protective layer; and a backlight module is disposed on the other side of the array substrate opposite to the protective layer. The sensing device according to claim 1, further comprising a flat layer disposed on the substrate and covering the active element and the photosensitive element, the flat layer having a substantially flat upper surface. The sensing device according to claim 2, wherein a portion of an upper surface of the flat layer is adjacent to the grooves. The sensing device according to claim 1, wherein the range of the radius of curvature R is 15 micrometers (μm) ≦ R ≦ 100 micrometers (μm). The sensing device according to claim 1, wherein the protective layer has a thickness, and the thickness H ranges from 10 micrometers (μm) ≦ H ≦ 500 micrometers (μm). The sensing device according to claim 2, wherein the center of curvature is located on the other side of the upper surface of the flat layer relative to the protective layer. The sensing device according to claim 1, wherein a medium in the groove has a first refractive index, and a material of the protective layer has a second refractive index, wherein the first refractive index is smaller than the second refractive index . The sensing device according to claim 7, wherein a range of the first refractive index is about 1 to about 1.2, and a range of the second refractive index is about 1.35 to about 1.6. The sensing device according to claim 7, wherein the medium is vacuum or air. The sensing device according to claim 1, wherein the protective layer has a first portion and a second portion of different materials, the second portion is located between the first portion and the array substrate, and the groove is located in the second Section. The sensing device according to claim 10, wherein a medium in the groove has a first refractive index, a material of the first portion has a second refractive index, and a material of the second portion has a third refractive index , Wherein the first refractive index is smaller than the second refractive index and the third refractive index. The sensing device according to claim 1, wherein the array substrate further includes a plurality of first signal lines and a plurality of second signal lines, wherein any two adjacent first signal lines and any two adjacent second signal lines define either The range of the sensing unit. The sensing device according to claim 12, wherein the at least one light-transmitting area is located between the photosensitive element and the adjacent first signal line or the second signal line. The sensing device according to claim 1, wherein the array substrate has a peripheral region, the peripheral region surrounds the sensing units, and a frame adhesive is provided between the protective layer and the array substrate in the peripheral region.