CN115641621A

CN115641621A - Sensing element substrate

Info

Publication number: CN115641621A
Application number: CN202211397802.1A
Authority: CN
Inventors: 苏志中; 陈信学
Original assignee: AU Optronics Corp
Current assignee: AU Optronics Corp
Priority date: 2022-05-06
Filing date: 2022-11-09
Publication date: 2023-01-24
Also published as: TWI787126B; TW202345031A

Abstract

A sensing element substrate comprises a light-transmitting substrate, a switch element, a plurality of photosensitive elements, a first insulating layer and a first shading layer. The switch element is located on the transparent substrate. The photosensitive elements are electrically connected with the switch elements and each comprise a first electrode, a photosensitive layer and a second electrode. The material of the first electrode includes molybdenum and molybdenum oxide. The photosensitive layer is located on the first electrode. The second electrode is located on the photosensitive layer. The first insulating layer is located on the photosensitive element. The first light shielding layer is located on the first insulating layer and has a plurality of first openings, and each first opening overlaps each photosensitive element.

Description

Sensing element substrate

Technical Field

The invention relates to a sensing element substrate.

Background

The fingerprint sensor under the optical Organic Light Emitting Diode (OLED) screen is one of the key development items of the fingerprint sensor, a light source is reflected after contacting a finger through protective glass (cover glass), then passes through the protective glass and a light-transmitting area of the organic light emitting diode, and finally, light reaches the fingerprint sensor through a light collimation structure. The fingerprint sensor will determine whether there is incident light signal, and then the sensing signals of the fingerprint sensor are different due to different light intensities reflected by different fingerprints (such as fingerprint peaks and fingerprint valleys), and the sensing signals are converted into different gray scales for display after being processed by the chip signal. The higher the sensing sensitivity of the fingerprint sensor, the stronger the fingerprint sensor signal.

However, in a strong light environment, light is reflected to the light collimating structure after penetrating through the finger and reaching the fingerprint sensor, the light collimating structure reflects the light to an external object (such as a battery or a high reflector of a middle frame), and the external object reflects the light back to the light collimating structure, which causes a stray photocurrent to be received by the fingerprint sensor.

Disclosure of Invention

The invention provides a sensing element substrate, which can improve the sensing sensitivity of the sensing element substrate and reduce the noise of a photosensitive element.

The sensing device substrate of an embodiment of the invention includes a transparent substrate, a switch device, a plurality of photosensitive devices, a first insulating layer, and a first light shielding layer. The switch element is located on the transparent substrate. The photosensitive elements are electrically connected with the switch elements and each comprise a first electrode, a photosensitive layer and a second electrode. The material of the first electrode includes molybdenum and molybdenum oxide. The photosensitive layer is located on the first electrode. The second electrode is located on the photosensitive layer. The first insulating layer is located on the photosensitive element. The first light shielding layer is located on the first insulating layer and has a plurality of first openings, and each first opening overlaps each photosensitive element.

In view of the above, in the sensing device substrate according to an embodiment of the invention, since the material of the first electrode includes molybdenum and molybdenum oxide, and the reflectivity of molybdenum oxide is lower than that of molybdenum, in a strong light environment, light passes through the first opening of the first light shielding layer after penetrating through the finger, and after striking the first electrode, the light is not reflected to the first light shielding layer by the first electrode and then reflected to other light sensing devices, so that stray photocurrent generated by each light sensing device can be avoided. Therefore, the sensitivity of the substrate of the sensing element is improved, and the noise of the photosensitive element is reduced.

Drawings

Various aspects of the disclosure can be understood from the following detailed description when read in conjunction with the accompanying drawings. It is noted that the various features of the drawings are not to scale as is standard practice in the art. In fact, the dimensions of the features described may be arbitrarily increased or decreased for clarity of discussion.

Fig. 1 is a schematic top view of a sensing device substrate according to an embodiment of the invention.

Fig. 2 is a schematic sectional view along the sectional line 2-2' of fig. 1.

Fig. 3 is an equivalent circuit diagram of the sensing element substrate.

FIG. 4 is a cross-sectional view of a sensing device substrate according to another embodiment of the invention.

Fig. 5 is an enlarged schematic view of the region R1 of fig. 1.

FIG. 6 is a schematic top view of a sensing device substrate according to an embodiment of the invention.

Fig. 7 is a schematic sectional view taken along section line 7-7' of fig. 6.

Fig. 8 is an enlarged schematic view of the region R2 of fig. 6.

FIG. 9 is a cross-sectional view of a substrate of a sensor device according to another embodiment of the invention.

FIG. 10 is a schematic top view of a sensing device substrate according to another embodiment of the invention.

Fig. 11 is a schematic sectional view taken along section line 11-11' of fig. 10.

Fig. 12 is an enlarged schematic view of the region R3 of fig. 10.

FIG. 13 is a cross-sectional view of a substrate of a sensor device according to another embodiment of the invention.

FIG. 14 is a schematic top view of a sensing device substrate according to another embodiment of the invention.

Fig. 15 is a cross-sectional view taken along section line 15-15' of fig. 14.

Fig. 16 is an enlarged schematic view of the region R4 of fig. 14.

FIG. 17 is a schematic top view of a sensing device substrate according to another embodiment of the invention.

Description of the reference numerals:

10,10A,10B, 10D: sensing element substrate

10E,10F,10G: sensing element substrate

2-2',7-7',11-11': cutting line

15-15': cutting line

100: light-transmitting substrate

102: channel region

104: doped source region

104a: source electrode heavily doped region

104b: lightly doped source region

106: doped drain region

106a: heavily doped drain region

106b: lightly doped drain region

108,108A,108C,108D: a first electrode

108G: a first electrode

108a: first layer

108b: second layer

108c: third layer

110: photosensitive layer

112: second electrode

114: a first flat layer

116: a first insulating layer

118: a second insulating layer

120: a second flat layer

122: a third insulating layer

124: a third flat layer

126: a fourth insulating layer

128: micro-lens

130: signal line

132: input signal line

134: input signal line

136: series connection wiring

138: first wire

140: second routing

144,144F,144G: shading pattern

144a: first layer

144b: second layer

144c: third layer

200: route of travel

A: symbol

BF: buffer layer

BM1: a first light-shielding layer

BM1a: first layer

BM1b: second layer

BM1c: third layer

BM2: a second light-shielding layer

BM3: the third light-shielding layer

C: capacitor with a capacitor element

CH1: channel layer

D1: drain electrode

d1: minimum distance

F: finger(s)

G1, G2: grid electrode

GI1: gate insulating layer

H1, H2, H3, H4, H5, H6: opening(s)

ILD: interlayer insulating layer

LVSS: reference voltage line

LVDD: power supply line

OP1: first opening

P1, P2: node point

PD: photosensitive element

R: electric resistance

R1, R2, R3, R4: region(s)

S1: source electrode

T1: a first switch element

T2: a second switching element

T2a: first end

T2b: second end

V1, V2: opening of the container

Detailed Description

The terms "about," "about," or "approximately" as used herein shall generally mean within twenty percent, preferably within ten percent, preferably within five percent of a given value or range. The numerical quantities provided herein are approximate, meaning that the terms "about", "about" or "approximately" may be used unless otherwise indicated. The terms "substantially", "essentially" or "substantially" as used herein are intended to reflect process limitations or situations in which the present disclosure may be significantly varied while still being capable of effective operation. Also, it should be understood that, in accordance with the teachings of the present disclosure, the skilled person may implement the embodiments in the present disclosure with different results due to process limitations, but the skilled person should recognize that the implementation results are "substantially" or "essentially" the same as the embodiments in the present disclosure.

Fig. 1 is a schematic top view of a sensing device substrate 10 according to an embodiment of the invention. Fig. 2 is a schematic sectional view along the sectional line 2-2' of fig. 1. Fig. 3 is an equivalent circuit diagram of the sensing element substrate 10. Referring to fig. 1, fig. 2 and fig. 3, the sensing device substrate 10 includes a transparent substrate 100, a first switch device T1, a second switch device T2 and a plurality of photosensitive devices PD.

The material of the transparent substrate 100 may be glass. However, the invention is not limited thereto, and in other embodiments, the material of the transparent substrate 100 may also be quartz, organic polymer, or other transparent materials.

The first switch device T1 is disposed on the transparent substrate 100, and the plurality of photo sensors PD are electrically connected to the first switch device T1. The first switching element T1 is a thin film transistor, and includes a gate G1, a source S1, a drain D1 and a channel layer CH1, and the gate G1 overlaps the channel layer CH1. The channel layer CH1 further includes a channel region 102, a source doped region 104 and a drain doped region 106, the drain doped region 106 may further include a heavily doped drain region 106a and a lightly doped drain region 106b, and the source doped region 104 may further include a heavily doped source region 104a and a lightly doped source region 104b.

The sensing device substrate 10 includes a gate insulating layer GI and an interlayer insulating layer ILD. A gate insulating layer GI is sandwiched between the gate G1 and the channel layer CH1. The interlayer insulating layer ILD covers the gate G1. The source S1 and the drain D1 are disposed on the interlayer insulating layer ILD and electrically connected to the channel CH1 through the openings H1 and H2, respectively. The openings H1 and H2 penetrate through the gate insulating layer GI and the interlayer insulating layer ILD. In some embodiments, the gate G1, the source S1 and the drain D1 are made of materials including (but not limited to): a metallic material, such as chromium, gold, silver, copper, tin, lead, hafnium, tungsten, molybdenum, neodymium, titanium, tantalum, aluminum, zinc, or alloys thereof, or other conductive materials. In one embodiment, the sensing device substrate 10 includes a buffer layer BF disposed between the first switch device T1 and the transparent substrate 100.

In the present embodiment, the first switching element T1 is a top gate thin film transistor as an example, but the invention is not limited thereto. In other embodiments, the first switching element T1 may also be a bottom gate type or other type of thin film transistor.

The photo sensors PD are disposed on the interlayer insulating layer ILD, and each include a first electrode 108, a photo-sensitive layer 110, and a second electrode 112. A photosensitive layer 110 is located on the first electrode 108 and a second electrode 112 is located on the photosensitive layer 110. In other words, the photosensitive layer 110 is sandwiched between the first electrode 108 and the second electrode 112. The first electrode 108 of the photosensitive element PD is electrically connected to the drain D1 of the first switch element T1, and the source S1, the drain D1 and the first electrode 108 may belong to the same film layer (i.e., the materials of these components may be the same selectively), but the invention is not limited thereto.

In the present embodiment, the sensing device substrate 10 further includes a first planarization layer 114, a first insulating layer 116, and a first light-shielding layer BM1. The first planarization layer 114 covers the first switching element T1 and has an opening V1 overlapping the photosensitive layer 110, and the second electrode 112 of the photosensitive element PD extends into the opening V1 to cover the exposed portion of the photosensitive layer 110 from the opening V1.

In the present embodiment, the photosensitive layer 110 is made of silicon-rich oxide (SRO) or other suitable materials. The second electrode 112 is, for example, a light-transmissive electrode, and the material of the light-transmissive electrode includes metal oxides, such as: indium tin oxide, indium zinc oxide, aluminum tin oxide, aluminum zinc oxide, or other suitable oxide, or a stack of at least two of the foregoing.

The first insulating layer 116 is located on the photosensitive element PD, in other words, the second electrode 112 is located between the first flat layer 114 and the first insulating layer 116. The first light-shielding layer BM1 is disposed on the first insulating layer 116, the first light-shielding layer BM1 has a plurality of first openings OP1, and each of the first openings OP1 overlaps each of the photosensitive elements PD, so that light reflected by the target (i.e. the fingerprint of the finger F) can be collimated and incident on the photosensitive elements PD at a desired angle, which is helpful for improving the sensing sensitivity of the sensing element substrate 10. The material of the first electrode 108 includes molybdenum and molybdenum oxide (MoO) _x ). In some embodiments, the first electrode 108 may be a moly aluminum molybdenum(Mo/Al/Mo) and molybdenum oxide (MoO) _x ). Since the reflectivity of molybdenum oxide is lower than that of molybdenum. For example, the reflectance of molybdenum is about 60%, and the reflectance of molybdenum oxide is about 10%. Therefore, noise (noise) caused by stray light current generated by multiple reflections after the light sensing element PD is subjected to strong light incidence can be avoided. For example, in a strong light environment, light is not transmitted along the path 200, that is, the light passes through the finger F and passes through the first opening OP1 of the first light shielding layer BM1, and after reaching the first electrode 108, the light is not reflected by the first electrode 108 to the first light shielding layer BM1 and then reflected to other photo sensors PD, so that stray photocurrent generated by each photo sensor PD can be prevented. Thus, the sensitivity of the sensor substrate 10 can be improved and the noise of the photo sensor PD can be reduced.

In one embodiment, the first electrode 108 is a double-layer structure including a first layer 108a and a second layer 108b disposed on the first layer 108a, the first layer 108a is made of molybdenum (e.g., molybdenum aluminum molybdenum (Mo/Al/Mo)), and the second layer 108b is made of molybdenum oxide. The molybdenum oxide of the second layer 108b can be formed by oxidizing molybdenum with water, or by sputtering a molybdenum oxide target, and can be formed by a suitable method according to actual equipment.

The sensing device substrate 10 further includes a second insulating layer 118, a second planarization layer 120, a third insulating layer 122, a third planarization layer 124, and a fourth insulating layer 126 sequentially disposed on the first insulating layer 116. The sensor substrate 10 further includes a second light-shielding layer BM2, a third light-shielding layer BM3, and a plurality of micro-lenses (micro-lenses) 128. The second insulating layer 118 is located between the first insulating layer 116 and the first light-shielding layer BM1. The second light-shielding layer BM2 is located on the third insulating layer 122 and has a plurality of openings respectively corresponding to the light-sensing elements PD. The third light-shielding layer BM3 is located on the fourth insulating layer 126 and has a plurality of openings respectively corresponding to the photosensitive elements PD.

The second light-shielding layer BM2 has a first layer BM2a and a second layer BM2b located on the first layer BM2 a. The third light-shielding layer BM3 has a first layer BM3a and a second layer BM3b on the first layer BM3 a. The material of the first layer BM2a and the first layer BM3a includes molybdenum (for example, molybdenum aluminum molybdenum (Mo/Al/Mo)), and the material of the second layer BM2b and the second layer BM3b is molybdenum oxide. Since the openings of the second light-shielding layer BM2 and the openings of the third light-shielding layer BM3 overlap the photosensitive elements PD, light reflected by the target (i.e., the fingerprint of the finger F) can be collimated and incident on the photosensitive elements PD at a desired angle, which is helpful to improve the sensing sensitivity of the sensing element substrate 10. The micro-lens 128 may focus the light to the photo-sensing element PD to improve light collimation. For example, the microlens 128 of the present embodiment is a plano-convex lens, and the convex surface of the plano-convex lens faces away from the photosensitive element PD.

The first insulating layer 116, the second insulating layer 118, the third insulating layer 122, the fourth insulating layer 126, the first planarization layer 114, the second planarization layer 120, the third planarization layer 124, and the micro-lenses 128 may be made of inorganic materials (e.g., silicon oxide, silicon nitride, silicon oxynitride, silicon aluminum oxide, or a stack of at least two of the above materials), organic materials, or a combination thereof. Further, the above-mentioned layer may be a single layer structure, or may be a multilayer stacked structure.

In one embodiment, the sensing device substrate 10 further includes at least one signal line 130. The area of each first electrode 108 is larger than that of each photosensitive layer 110, and the minimum distance d1 between each first electrode 108 and the adjacent at least one signal line 130 in the horizontal direction is 0.1 μm to 5 μm. Therefore, the area of the first electrode 108 can be increased, so that the area of the single photosensitive element PD is increased, and thus, the photosensitive signal can be increased, the sensing sensitivity is increased, or the voltage step of the sensing operation is reduced, and the energy consumption is reduced; further, the light can be prevented from being transmitted along the path 200 in a strong light environment, that is, the light penetrates through the finger F and passes through the first opening OP1 of the first light shielding layer BM1, and after reaching the first electrode 108, the light is not reflected to the first light shielding layer BM1 by the first electrode 108, and then is reflected to other photo sensing elements PD, so that the stray photocurrent generated by each photo sensing element PD can be prevented.

For convenience of explanation, the interlayer insulating layer ILD and the first planarization layer 114 are omitted from fig. 1, and the symbol of the opening of the interlayer insulating layer ILD starts with "H" and the symbol of the opening of the first planarization layer 114 starts with "V". In one embodiment, the sensing device substrate 10 further includes an input signal line 132 and an input signal line 134. The source S1 of the first switch element T1 is coupled to the reference voltage line LVSS for receiving the reference voltage VSS, the gate G1 of the first switch element T1 is coupled to the input signal line 132 for receiving the gate driving signal SR _ R [ n ] providing the reset function, and the drain D1 of the first switch element T1 is coupled to the node P1. One end of the photo sensing device PD is coupled to the node P1, and the other end of the photo sensing device PD is coupled to the input signal line 134 through the opening V2 in the first planarization layer 114 for receiving the gate driving signal SR _ W [ n ] providing the write function. The photosensitive element PD of the present embodiment is a structure of a capacitor C and a resistor R (1C 1R), and the capacitor C is connected in series with the resistor R, so that the capacitor C can form a storage capacitor to realize a fingerprint identification function. The sensing element substrate 10 further includes an electrode portion 133, and the electrode portion 133 is electrically connected to the input signal line 134 through the opening H6. In the present embodiment, the electrode portion 133, the source S1, the drain D1 and the first electrode 108 may be the same film. The input signal line 132 and the input signal line 134 may be formed in the same layer as the gates G1 and G2.

The gate G2 of the second switch element T2 is coupled to the photosensitive element PD through a node P1, for example, the gate G2 of the second switch element T2 is coupled to the photosensitive element PD through an opening H3 located on the interlayer insulating layer ILD, and a first terminal T2a of the second switch element T2 is coupled to the power supply line LVDD through an opening H4 located on the interlayer insulating layer ILD to receive the power supply voltage VDD. The second terminal T2b of the second switching element T2 outputs the fingerprint determination voltage Sout [ m ] to the signal line 130 through the node P2. For example, the second terminal T2b of the second switch device T2 is coupled to the signal line 130 through the opening H5 located in the interlayer insulating layer ILD.

Further, when the voltage value at the node P1 is sufficient to turn on the second switch device T2, the voltage value of the fingerprint determination voltage Sout [ m ] rises, and the charge of the capacitor C is discharged through the resistor R. Moreover, since the resistance of the resistor R varies according to the vertical distance between the resistor R and the skin surface of the user's finger F, the discharge time of the capacitor C also varies accordingly. As described above, the fingerprint determination voltage Sout [ m ] of the present embodiment determines the rising amplitude of the fingerprint determination voltage Sout [ m ] according to the discharge time between the capacitor C and the resistor R. Then, the fingerprint determination voltage Sout [ m ] of the present embodiment can be compared with the threshold voltage to determine whether the fingerprint on the skin surface of the finger F of the user sensed by the photosensitive element PD is a valley line or a ridge line. Therefore, the valley and the ridge of the fingerprint can be identified by the change of the resistance value of the resistor R.

Fig. 4 is a schematic cross-sectional view of a sensing device substrate 10A according to another embodiment of the invention. Referring to fig. 4, a difference between the sensing device substrate 10A of the present embodiment and the sensing device substrate 10 of fig. 2 is that the first electrode 108A is a three-layer structure including a first layer 108A, a second layer 108b and a third layer 108c, the second layer 108b is located between the first layer 108A and the third layer 108c, the first layer 108A is made of molybdenum oxide, the second layer 108b is made of molybdenum (e.g., molybdenum aluminum molybdenum (Mo/Al/Mo)), and the third layer 108c is made of molybdenum oxide.

The molybdenum oxide of the first layer 108a can be formed by sputtering a molybdenum oxide target. The molybdenum oxide of the third layer 108c may be formed by oxidizing molybdenum with water or by sputtering a molybdenum oxide target, and may be formed by a suitable method according to actual equipment. Since the reflectivity of the molybdenum oxide is lower than that of the molybdenum, in a strong light environment, light passes through the first opening OP1 of the first light-shielding layer BM1 after passing through a finger, and is reflected by an external component (not shown) such as a battery after passing through the transparent substrate 100, and is not reflected by the first electrode 108, in other words, it is avoided that multiple reflections between the external component and the first electrode 108 are reflected back to the first light-shielding layer BM1 and are reflected again to cause the generation of stray photocurrent in each photosensitive element PD.

Referring back to fig. 2, the first light-shielding layer BM1 is a three-layer structure including a first layer BM1a, a second layer BM1b and a third layer BM1c, the second layer BM1b is located between the first layer BM1a and the third layer BM1c, the first layer BM1a is made of molybdenum oxide, the second layer BM1b is made of molybdenum (for example, molybdenum aluminum molybdenum (Mo/Al/Mo)), and the third layer BM1c is made of molybdenum oxide. Since the reflectivity of the molybdenum oxide is lower than that of the molybdenum, in a strong light environment, light passes through the finger F, passes through the first opening OP1 of the first light-shielding layer BM1, passes through the transparent substrate 100, is reflected by an external component (not shown), such as a battery, and is not reflected by the first light-shielding layer BM1 to the photosensitive element PD. Therefore, the stray photocurrent generated by each photo sensor PD can be avoided. The molybdenum oxide of the first layer BM1a and the third layer BM1c can be formed by sputtering a molybdenum oxide target.

Fig. 5 is an enlarged schematic view of the region R1 in fig. 1, and referring to fig. 5 and fig. 2 together, the sensing device substrate 10 further includes a plurality of serial traces 136. Fig. 5 only shows the first electrode 108, the second electrode 112 and the serial trace 136, and the other components are omitted. Each serial trace 136 is connected to two adjacent second electrodes 112, and a portion of each first electrode 108 does not overlap the serial trace 136 in the vertical direction. Therefore, the parasitic capacitance between the first electrode 108 and the second electrode 112 can be reduced.

For example, the symbol a indicates an overlapping portion of the serial trace 136 and the first electrode 108, i.e., the overlapping portion is a serial area of the serial trace 136. In the present embodiment, the serial trace 136 includes a plurality of first traces 138 and a plurality of second traces 140, and the extending direction of each first trace 138 is perpendicular to the extending direction of each second trace 140 and the arrangement direction of two adjacent second electrodes 112 connected by the second traces 140. With such a configuration, the total of the serial areas of the serial traces 136 can be reduced. For example, this can be reduced by about 84.3%. As a result, the parasitic capacitance between the first electrode 108 and the serial trace 136 can be reduced.

Fig. 6 is a schematic top view of a sensing device substrate 10B according to an embodiment of the invention. Fig. 7 is a cross-sectional view taken along line 7-7' of fig. 6. Fig. 8 is an enlarged schematic view of the region R2 of fig. 6, and fig. 8 only shows the first electrode 108, the second electrode 112 and the serial trace 136, and other components are omitted. Referring to fig. 6 to 8, a difference between the sensing device substrate 10B of the present embodiment and the sensing device substrate 10 of fig. 1 is that each of the first electrodes 108B is overlapped with the serial trace 136 in the vertical direction. Therefore, the area of the first electrode 108B and the serial trace 136 can be reduced, and the parasitic capacitance therebetween can be reduced. With such a configuration, the total of the serial areas of the serial traces 136 can be reduced. For example, this can be reduced by about 45.7%. As a result, the parasitic capacitance between the first electrode 108B and the serial trace 136 can be reduced.

Fig. 9 is a schematic cross-sectional view of a sensing element substrate 10C according to another embodiment of the invention, and referring to fig. 9, a difference between the sensing element substrate 10C of the present embodiment and the sensing element substrate 10B of fig. 7 is that a first electrode 108C is a three-layer structure including a first layer 108a, a second layer 108B and a third layer 108C, the second layer 108B is located between the first layer 108a and the third layer 108C, the first layer 108a is made of molybdenum oxide, the second layer 108B is made of molybdenum (e.g., molybdenum aluminum molybdenum (Mo/Al/Mo)), and the third layer 108C is made of molybdenum oxide.

Fig. 10 is a schematic top view of a sensing device substrate 10D according to another embodiment of the invention. Fig. 11 is a schematic sectional view taken along section line 11-11' of fig. 10. Fig. 12 is an enlarged schematic view of the region R3 of fig. 10, and fig. 12 only shows the first electrode 108D, the second electrode 112 and the serial trace 136, and other components are omitted. Referring to fig. 10 to 12, a difference between the sensing device substrate 10D of the present embodiment and the sensing device substrate 10 of fig. 1 is that the sensing device substrate 10D further includes at least one light-shielding pattern 144. The light shielding patterns 144 are located between two adjacent first electrodes 108, and at least one light shielding pattern 144 is spaced apart from two adjacent first electrodes 108 in the horizontal direction.

In one embodiment, the material of the light-shielding pattern 144 is the same as the material of the first electrode 108. For example, the light blocking pattern 144 has a double-layer structure including a first layer 144a and a second layer 144b on the first layer 144a, the first layer 144a is made of molybdenum (e.g., molybdenum aluminum molybdenum (Mo/Al/Mo)), and the second layer 144b is made of molybdenum oxide. Since the reflectance of molybdenum oxide is lower than that of molybdenum, multiple reflection of light at the first light-shielding layer BM1 and the first electrode 108 can be avoided. The serial area of the serial trace 136 of the present embodiment is the same as the serial area of the serial trace 136 of the sensor substrate 10 of fig. 1, and is not described herein again. In other embodiments, the material of the light-shielding pattern 144 may be black matrix (black matrix).

Referring to fig. 13, a cross-sectional view of a sensing element substrate 10E according to another embodiment of the invention is shown, and referring to fig. 13, a difference between the sensing element substrate 10E of the present embodiment and the sensing element substrate 10D of fig. 11 is that the light-shielding pattern 144E of the sensing element substrate 10E of the present embodiment is a three-layer structure including a first layer 144a, a second layer 144b and a third layer 144c, the second layer 144b is located between the first layer 144a and the third layer 144c, the first layer 144a is made of molybdenum oxide, the second layer 144b is made of molybdenum (e.g., molybdenum aluminum molybdenum (Mo/Al/Mo)), and the third layer 144c is made of molybdenum oxide. Since the reflectivity of the molybdenum oxide is lower than that of the molybdenum, in a strong light environment, light passes through the first opening OP1 of the first light-shielding layer BM1 after passing through a finger, passes through the light-transmitting substrate 100, is reflected by an external member (not shown) such as a battery, and is not reflected by the first light-shielding layer BM1 to the photosensitive element PD. Therefore, the stray photocurrent generated by each photo sensor PD can be avoided.

Fig. 14 is a schematic top view of a sensing device substrate 10F according to another embodiment of the invention. Fig. 15 is a cross-sectional view taken along section line 15-15' of fig. 14. Fig. 16 is an enlarged schematic view of the region R4 in fig. 14, please refer to fig. 14 to fig. 16, the difference between the sensing element substrate 10F of the present embodiment and the sensing element substrate 10D in fig. 10 is that each of the first electrodes 108F overlaps the serial trace 136 in the vertical direction. Therefore, the area of the first electrode 108F and the serial trace 136 can be reduced, and the parasitic capacitance therebetween can be reduced. With such a configuration, the total of the serial areas of the serial traces 136 can be reduced. For example, this can be reduced by about 45.7%. Thus, the parasitic capacitance between the first electrode 108F and the serial trace 136 can be reduced. The light shielding pattern 144F of the present embodiment has a double-layer structure including a first layer 144a and a second layer 144b on the first layer 144 a.

Fig. 17 is a schematic cross-sectional view of a sensing element substrate 10G according to another embodiment of the invention. Referring to fig. 17, a difference between the sensing device substrate 10G of the present embodiment and the sensing device substrate 10F of fig. 15 is that the light-shielding pattern 144G of the sensing device substrate 10G of the present embodiment is a three-layer structure including a first layer 144a, a second layer 144b and a third layer 144c, the second layer 144b is located between the first layer 144a and the third layer 144c, the first layer 144a is made of molybdenum oxide, the second layer 144b is made of molybdenum (e.g., molybdenum aluminum molybdenum (Mo/Al/Mo)), and the third layer 144c is made of molybdenum oxide. Since the reflectivity of the molybdenum oxide is lower than that of the molybdenum, in a strong light environment, light passes through the first opening OP1 of the first light-shielding layer BM1 after passing through a finger, passes through the light-transmitting substrate 100, is reflected by an external member (not shown) such as a battery, and is not reflected by the first light-shielding layer BM1 to the photosensitive element PD. Therefore, the stray photocurrent generated by each photo sensing element PD can be avoided.

In summary, the material of the first electrode of the sensing element substrate of the invention includes molybdenum and molybdenum oxide (MoO) _x ). Since the reflectivity of molybdenum oxide is lower than that of molybdenum. For example, the reflectivity of molybdenum is about 60%, and the reflectivity of molybdenum oxide is about 10%. Therefore, noise (noise) caused by stray light current generated by multiple reflections after the photosensitive element is subjected to strong light incidence can be avoided. For example, in a strong light environment, light passes through the first opening of the first light shielding layer after penetrating through the finger, and after striking the first electrode, the light is not reflected to the first light shielding layer by the first electrode and then reflected to other photosensitive elements, so that stray photocurrent generated by each photosensitive element can be avoided. Therefore, the sensitivity of the substrate of the sensing element is improved, and the noise of the photosensitive element is reduced.

Claims

1. A sensing element substrate, comprising:

a light-transmitting substrate;

a switch element located on the transparent substrate;

a plurality of photosensitive elements electrically connected to the switch element, each of which comprises:

a first electrode, wherein the material of the first electrode comprises molybdenum and molybdenum oxide;

a photosensitive layer located on the first electrode; and

a second electrode on the photosensitive layer;

a first insulating layer on the photosensitive elements; and

a first light-shielding layer on the first insulating layer, wherein the first light-shielding layer has a plurality of first openings, and each of the first openings overlaps each of the photosensitive elements.

2. The sensing element substrate of claim 1, wherein the first electrode is a bi-layer structure comprising a first layer and a second layer disposed on the first layer, the first layer comprises molybdenum, and the second layer comprises molybdenum oxide.

3. The sensing device substrate of claim 1, wherein the first electrode is a three-layer structure including a first layer, a second layer and a third layer, the second layer is disposed between the first layer and the third layer, the first layer is made of molybdenum oxide, the second layer comprises molybdenum, and the third layer is made of molybdenum oxide.

4. The sensor substrate of claim 1, wherein the first light-shielding layer comprises a first layer, a second layer and a third layer, the second layer is disposed between the first layer and the third layer, the first layer is made of molybdenum oxide, the second layer comprises molybdenum, and the third layer is made of molybdenum oxide.

5. The sensing element substrate of claim 1, further comprising:

and a plurality of serial connection wires respectively connected with two adjacent second electrodes, wherein each first electrode is not overlapped with the serial connection wires in the vertical direction.

6. The sensing element substrate of claim 1, wherein the serial traces include a plurality of first traces and a plurality of second traces, and an extending direction of each of the first traces is perpendicular to an extending direction of each of the second traces and an arrangement direction of two adjacent second electrodes connected by the second traces.

7. The sensing element substrate of claim 1, further comprising:

and the plurality of serial wirings are respectively connected with the two adjacent second electrodes, wherein each first electrode is overlapped with the serial wirings in the vertical direction.

8. The sensing element substrate of claim 1, further comprising:

at least one light shielding pattern located between two adjacent first electrodes, wherein the at least one light shielding pattern is spaced apart from the two adjacent first electrodes in a horizontal direction, the at least one light shielding pattern is a double-layer structure including a first layer and a second layer located on the first layer, and the first layer is made of molybdenum oxide.

9. The sensing element substrate of claim 1, further comprising:

the light shielding pattern is arranged between two adjacent first electrodes, the at least one light shielding pattern is spaced from the two adjacent first electrodes in the horizontal direction, the at least one light shielding pattern is of a three-layer structure comprising a first layer, a second layer and a third layer, the second layer is arranged between the first layer and the third layer, the first layer is made of molybdenum oxide, the second layer is made of molybdenum, and the third layer is made of molybdenum oxide.

10. The sensing element substrate of claim 1, further comprising:

at least one signal line, wherein the area of each first electrode is larger than that of each photosensitive layer, and the minimum distance between each first electrode and the adjacent at least one signal line in the horizontal direction is 0.1-5 μm.