WO2020199155A1 - Thin film semiconductor structure and related operation method, and handheld apparatus having fingerprint sensing function - Google Patents

Abstract

Disclosed is a thin film semiconductor structure (12) coupled to a reading circuit (14) outside the thin film semiconductor structure, wherein the reading circuit includes a capacitor (142). The thin film semiconductor structure comprises: a substrate (11), and a sensing unit group provided on the substrate, wherein the sensing unit group and the reading circuit operate together during a sensing operation or a reading operation; the sensing unit group includes a plurality of sensing units (120 & 122); and each of the sensing units can be set, during the sensing operation, as a positive integral configuration or a negative integral configuration to generate a common sensing result, and the plurality of sensing units charge or discharge, during the reading operation, the capacitor of the reading circuit according to the common sensing result.

Description

Thin film semiconductor structure, related operation method and handheld device with fingerprint sensing function Technical field

This application relates to a semiconductor structure, and more particularly to a thin-film semiconductor structure and related operation methods and a handheld device with fingerprint sensing function.

Background technique

In fingerprint sensing, photodiodes are often used as the sensing components of the under-screen sensors. In order to improve the accuracy of sensing, it is necessary to be able to determine the sensitivity of each photodiode. Today's under-screen sensors cannot accurately determine the sensitivity of each photodiode.

Therefore, further improvements and innovations are needed to overcome the above-mentioned problems.

Summary of the invention

One of the objectives of the present application is to disclose a semiconductor structure, in particular to a thin-film semiconductor structure and related operation methods and a handheld device with fingerprint sensing function to solve the above-mentioned problems.

An embodiment of the present application discloses a thin film semiconductor structure coupled to a reading circuit outside the thin film semiconductor structure, the reading circuit includes a capacitor, the thin film semiconductor structure includes: a substrate; and a sensing unit The group is configured on the substrate, the group of sensing units and the read circuit are operated in a sensing operation or a read operation together, the group of sensing units includes a plurality of sensing units, each The sensing unit can be set to a positive integration configuration or a negative integration configuration under the sensing operation to generate a common sensing result, wherein the multiple sensing units are based on the reading operation according to the The common sensing result charges or discharges the capacitor of the reading circuit.

An embodiment of the present application discloses an operating method for operating the aforementioned thin film semiconductor structure. The operating method includes: performing the aforementioned sensing operation, including: enabling the sensing unit group and the reading circuit The conduction path between them is non-conductive, and the photodiodes of the plurality of sensing units are exposed to produce the common sensing result; and performing the aforementioned reading operation includes: making the sensing unit group Conduction with the reading circuit, and allowing the plurality of sensing units to charge or discharge the capacitor of the reading circuit according to the common sensing result.

An embodiment of the present application discloses a handheld device with fingerprint sensing function for sensing the fingerprint of a specific object. The handheld device includes: a display screen assembly; and the aforementioned thin film semiconductor structure.

The thin film semiconductor structure disclosed in the present application includes a plurality of sensing units. Since each of the sensing units can be configured to change to a positive integration configuration or a negative integration configuration, the sensitivity of each sensing unit can be relatively accurately determined through multiple exposures, so as to facilitate subsequent execution Fingerprint sensing function.

Description of the drawings

FIG. 1 is a cross-sectional view of an embodiment of the image sensor of the application.

2 is a schematic diagram of the sensing unit group of the first embodiment of the sensing unit matrix of the thin film semiconductor structure of the image sensor of FIG. 1.

3 is a schematic diagram of the operation of the sensing unit group and the reading circuit of the image sensor of FIG. 2 in the first fingerprint sensing cycle.

4 is a schematic diagram of the operation of the sensing unit group and the reading circuit of the image sensor of FIG. 2 in the second fingerprint sensing cycle.

FIG. 5 is a circuit diagram of a sensing unit of the sensing unit group in FIG. 2.

6 is a circuit diagram of an equivalent circuit of the sensing unit group of FIG. 2 under the first fingerprint sensing cycle.

FIG. 7 is a schematic diagram of the sensing unit group of the second embodiment of the sensing unit matrix of the thin film semiconductor structure of the image sensor of FIG. 1.

8 is a schematic diagram of the operation of the sensing unit group and the reading circuit of the image sensor of FIG. 7 in the second fingerprint sensing cycle.

9 is a schematic diagram of the operation of the sensing unit group and the reading circuit of the image sensor of FIG. 7 under the third fingerprint sensing cycle.

FIG. 10 is a circuit diagram of an equivalent circuit of the sensing unit group of FIG. 7 in the first fingerprint sensing cycle.

FIG. 11 is a flowchart of an operating method of the image sensor of FIG. 1.

FIG. 12 is a flowchart of the operation of the operation method of FIG. 11.

FIG. 13 is a flowchart of the operation of the operation method of FIG. 11.

FIG. 14 is a schematic diagram of an embodiment of a handheld device of this application.

FIG. 15 is a cross-sectional view of an embodiment of a handheld device of this application.

Wherein, the reference signs are explained as follows:

10 Thin film semiconductor structure

11 Substrate

12 Sense unit group

13 Sense unit matrix

14 Reading the circuit

15 Image sensor

22 Sense unit group

30 Computing unit

40 How to operate

50 Handheld devices

52 Display assembly

54 Display panel

56 Protective cover

120 Sensing unit

122 Sensing unit

124 Sensing unit

140 Amplifier

142 Capacitors

144 Switch

400 Operation

402 Operation

404 Operation

406 Operation

500 Operation

502 Operation

504 Operation

506 Operation

I1 Photocurrent

I2 Photocurrent

V1 First voltage

V2 The second voltage

Vref Reference voltage

Q1 Charge

Q2 Charge

Q3 Charge

CR Reading line

CST1 First control line

CST2 Second control line

n0 Node

n_out output node

71 On and off

72 Switch on and off

81 Switch on and off

82 On and off

detailed description

The following disclosure provides a variety of implementations or examples, which can be used to realize different features of the disclosure. The specific examples of components and configurations described below are used to simplify the present disclosure. When it is conceivable, these narratives are only examples and are not intended to limit the content of this disclosure. For example, in the following description, forming a first feature on or on a second feature may include some embodiments where the first and second features are in direct contact with each other; and may also include In some embodiments, additional components are formed between the above-mentioned first and second features, so that the first and second features may not be in direct contact. In addition, the present disclosure may reuse component symbols and/or labels in multiple embodiments. Such repeated use is based on the purpose of brevity and clarity, and does not in itself represent the relationship between the different embodiments and/or configurations discussed.

Furthermore, the use of spatially relative terms here, such as "below", "below", "below", "above", "above" and similar, may be used to facilitate the description of the drawing The relationship between one component or feature relative to another component or feature is shown. In addition to the orientation shown in the figure, these spatially relative terms also cover a variety of different orientations in which the device is in use or operation. The device may be placed in other orientations (for example, rotated by 90 degrees or in other orientations), and these spatially-relative description words should be explained accordingly.

Although the numerical ranges and parameters used to define the broader scope of the present application are approximate numerical values, the relevant numerical values in the specific embodiments are presented here as accurately as possible. However, any value inherently inevitably contains the standard deviation due to individual test methods. Here, "about" usually means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a specific value or range. Or, the word "about" means that the actual value falls within the acceptable standard error of the average value, depending on the consideration of a person with ordinary knowledge in the technical field to which this application belongs. It should be understood that all ranges, quantities, values and percentages used herein (for example, to describe the amount of material, time length, temperature, operating conditions, quantity ratio and other Similar ones) have been modified by "about". Therefore, unless otherwise stated to the contrary, the numerical parameters disclosed in this specification and the accompanying patent scope are approximate values and can be changed according to requirements. At least these numerical parameters should be understood as the indicated effective number of digits and the value obtained by applying the general carry method. Here, the numerical range is expressed from one end point to the other end point or between the two end points; unless otherwise specified, the numerical range described here includes the end points.

The sensing unit disclosed in the present application is manufactured using a glass substrate thin film semiconductor process. Benefiting from the characteristics of the glass substrate thin film semiconductor process, the sensing unit can be switched between a positive integration configuration and a negative integration configuration, and the operation method disclosed in this application can be used to improve the performance of the sensing unit . Therefore, when the sensing unit is applied to an under-screen sensor, the accuracy can be improved.

FIG. 1 is a cross-sectional view of an embodiment of the image sensor 15 of the application. 1, the image sensor 15 includes a thin film semiconductor structure 10 and another semiconductor structure 23. The thin film semiconductor structure 10 is manufactured using a thin film transistor process, while the semiconductor structure 23 is not manufactured using a thin film transistor process. Specifically, the semiconductor structure 23 is Non-thin film semiconductor process using silicon substrate.

The thin film semiconductor structure 10 includes a substrate 11 and a sensing unit matrix 13, wherein the sensing unit matrix 13 is disposed on the substrate 11, and the substrate 11 includes a glass substrate.

The semiconductor structure 23 includes a substrate 21 and a reading circuit 14, wherein the reading circuit 14 is disposed on the substrate 21, and wherein the substrate 21 includes a silicon substrate.

2 is a schematic diagram of the sensing unit group 12 of the first embodiment of the sensing unit matrix 13 of the thin-film semiconductor structure 10 of the image sensor 15 of FIG. 1. The image sensor 15 can be used for optical under-screen fingerprint sensing, but This disclosure is not limited to this. The image sensor 15 includes a sensing operation and a reading operation. By sequentially performing the sensing operation once and the reading operation once, a cycle of fingerprint sensing is completed.

2, the sensing unit group 12 may be a part of the sensing unit matrix 13 of the thin film semiconductor structure 10 of FIG. 1. For example, the sensing unit matrix 13 of the thin film semiconductor structure 10 may include a plurality of sensing unit groups 12.

The sensing unit group 12 is coupled to the reading circuit 14 and includes sensing units 120 and 122. Each sensing unit 120 and 122 can be implemented using a photodiode (see photodiode 16 in FIG. 5). Due to the use of thin-film semiconductor manufacturing, the photodiode of the sensing unit 120 and the cathode of the photodiode of the sensing unit 122 can be separately given voltages. Therefore, the sensing units 120 and 122 can be designed through appropriate design and wiring, so that each The sensing units 120 and 122 have dual modes of a positive integration configuration and a negative integration configuration. Specifically, each sensing unit 120 and 122 can be set in a positive integration configuration or a negative integration configuration. It should be noted that it is not easy to apply different voltages to the cathodes of different photodiodes in a non-thin film semiconductor process using a silicon substrate. Therefore, if a non-thin film semiconductor process using a silicon substrate is used to achieve a positive integration configuration and a negative integration Configuring the dual-mode sensing units 120 and 122 will cost very expensive.

The advantage of the dual modes of the sensing units 120 and 122 having a positive integration configuration and a negative integration configuration is that when the sensing units 120 and 122 perform sensing, the reverse bias of the sensing units 120 and 122 will not be significant Change to improve linearity.

The sensing units 120 and 122 are controlled by the read line CR, the first control line CST1, and the second control line CST2. The first control line CST1 and the second control line CST2 are used to set the sensing units 120 and 122 Configure the dual mode for positive integration or negative integration. Taking the sensing unit 120 as an example, during the sensing operation, the sensing unit 120 is controlled by the first control line CST1 and the second control line CST2 to be set to a positive integration configuration or a negative integration configuration In order to perform subsequent exposure, and is controlled by the read line CR to provide its own sensing result (for example, charge ±Q1) to the node n0, which is described in detail in FIGS. 5 and 6. Similarly, the sensing unit 122 provides its own sensing result (for example, charge ±Q2) to the node n0. Therefore, the node n0 is simultaneously affected by the sensing results of the sensing units 120 and 122 and correspondingly generates a common sensing result. Specifically, the common sensing result is the voltage of the node n0.

The reading circuit 14 includes an amplifier 140, a capacitor 142, a switch 144, and a calculation unit 30.

The capacitor 142 is coupled between the input terminal and the output terminal of the amplifier 140. Based on this configuration, the capacitor 142 and the amplifier 140 integrate the voltage of the node n0. The output terminal of the amplifier 140 outputs the integrated result. The other input terminal of the amplifier 140 is coupled to the reference voltage Vref. In order to gradually reset the common sensing result on the node n0 back to the reference voltage Vref. Based on the characteristics of the virtual short circuit of the amplifier 140, the common sensing result on the node n0 is gradually reset to the reference voltage Vref. In some embodiments, the reference voltage Vref is a common-mode voltage, and the common-mode voltage is between a first voltage V1 (such as a ground voltage) and a second voltage V2 (such as a power supply voltage), wherein the first voltage V1 is lower than The second voltage V2.

The switch 144 is used to make the conduction path between the sensing unit group 12 and the reading circuit 14 conductive or non-conductive. In the sensing operation, the switch 144 is not conductive; in contrast, in the reading operation, the switch 144 is conductive. When turned on, the conduction path between the sensing unit group 12 and the reading circuit 14 is turned on, and the sensing units 120 and 122 charge or discharge the capacitor 142 of the reading circuit 14 according to the common sensing result on the node n0.

The calculation unit 30 stores the voltage of the output terminal of the amplifier 140 in each read operation. Based on all the stored voltages, the calculation unit 30 calculates the amplitude of the charge Q1 and the amplitude of the charge Q2 of the sensing results of the sensing units 120 and 122 after all the reading operations are completed, as detailed in FIGS. 3 to 4 .

<First embodiment>

3 to 4 show a first embodiment of the operation method of the sensing unit group 12 and the reading circuit 14.

FIG. 11 is a flowchart of a method of operating the image sensor 15 of FIG. 1. FIG. 12 is a flowchart of operation 404 of operation method 40 of FIG. 11. FIG. 12 is a flowchart of operation 406 of operation method 40 of FIG. 11. Operation method 40 includes operations 400, 402, 404, 406, 408, and 410, operation 404 includes operations 500 and 502, and operation 406 includes 600 and 602.

Referring to FIG. 11, in operation 400, the number of operations of the sensing operation and the reading operation is determined, that is, the number of cycles of fingerprint sensing is determined. In detail, the number of operations of the sensing operation and the reading operation is determined according to the number of the plurality of sensing units. In this embodiment, the number of operations is the same as the number of multiple sensing units. In addition, the sensing operation and the reading operation are repeatedly performed according to the number of operations.

The sensing unit group 12 has two sensing units 120 and 122. Therefore, the number of times of determining the sensing operation and the reading operation is twice, that is, it is determined that the cycle of two fingerprint sensing must be completed, so the sensing operation and the reading operation are repeated twice, as shown in FIG. 3 shows the first sensing operation and the first reading operation (that is, the first fingerprint sensing cycle), and the second sensing operation and the second reading operation shown in FIG. 4 (That is, the second fingerprint sensing cycle), respectively, detailed descriptions are as follows.

<First fingerprint sensing loop>

3 is a schematic diagram of the operation of the sensing unit group 12 and the reading circuit 14 of the image sensor 15 in FIG. 2 in the first fingerprint sensing cycle. Referring to FIG. 3 supplemented with FIG. 11, the operation method 40 proceeds to operation 402. In operation 402, the configuration combination of the sensing unit group is set before the sensing operation and the reading operation are performed. In detail, according to the set configuration combination, each of the sensing units is set to the positive integration configuration or the negative integration configuration.

Referring to Fig. 3, the configuration combinations related to the first fingerprint sensing cycle of Fig. 3 are shown in Table 1 below. The sensing unit 120 is set to a negative integration configuration (marked as "-" in FIG. 3) to charge the node n0 that provides a common sensing result, and the sensing unit 122 is set to a positive integration configuration ( It is marked as "+" in FIG. 3) to discharge the node n0 that provides the common sensing result.

Table 1

<First sensing operation>

Referring to FIG. 3 supplemented by FIG. 11, the operation method 40 proceeds to operation 404, in which the first sensing operation is performed. The first sensing operation is described in detail below.

Referring to FIG. 12, in operation 500, the conduction path between the sensing unit group and the reading circuit is made non-conducting. 3, the switch 144 is not turned on so that the conduction path between the sensing cell group 12 and the reading circuit 14 is not turned on.

Referring to FIG. 12, in operation 502, the plurality of sensing units are exposed to generate the common sensing result. 3, when the first exposure is performed, the sensing unit 120 set to the negative integration configuration is made to charge the node n0 to provide its own sensing result (charge + Q1) to the node n0; and The sensing unit 122 set in the forward integration configuration discharges the node n0 to provide its own sensing result (charge-Q2) to the node n0. Therefore, the node n0 is simultaneously affected by the sensing results of the sensing units 120 and 122 and correspondingly generates a common sensing result.

<First read operation>

Referring to FIG. 3 supplemented with FIG. 11, the operation method 40 proceeds to operation 406, in which the first reading operation is performed. The following details the first read operation.

Referring to FIG. 13, in operation 600, conduction is made between the sensing unit group and the reading circuit. 3, the switch 144 is turned on to turn on the conduction path between the sensing cell group 12 and the reading circuit 14.

Referring to FIG. 13, in operation 602, the plurality of sensing units are caused to charge or discharge the capacitor of the reading circuit according to the common sensing result. 3, the sensing units 120 and 122 charge or discharge the capacitor 142 of the reading circuit 14 according to the common sensing result on the node n0.

Ideally, the magnitude of charge +Q1 is the same as the magnitude of charge -Q2. In fact, for example, due to an adaptation error between the sensing units 120 and 122, the amplitude of the charge +Q1 is slightly different from the amplitude of the charge -Q2. When the magnitude of the charge +Q1 is greater than the magnitude of the charge -Q2, the sensing units 120 and 122 charge the capacitor 142 of the reading circuit 14 according to the common sensing result on the node n0. Alternatively, when the magnitude of the charge +Q1 is less than the magnitude of the charge -Q2, the sensing units 120 and 122 discharge the capacitor 142 of the reading circuit 14 according to the common sensing result on the node n0.

The calculation unit 30 stores the voltage of the output terminal of the amplifier 140 in the first fingerprint sensing cycle.

The operation method 40 proceeds to operation 408. In operation 408, it is determined whether all the sensing operations and the reading operations have been performed. Since all the sensing operations and reading operations have not been completed yet, the operation method 40 returns to operation 402 to perform the second fingerprint sensing cycle.

<Second fingerprint sensing loop>

4 is a schematic diagram of the operation of the sensing unit group 12 and the reading circuit 14 of the image sensor 15 in FIG. 2 in the second fingerprint sensing cycle. Since the second fingerprint sensing cycle of the embodiment of FIG. 4 is similar to the first fingerprint sensing cycle of the embodiment of FIG. 3, a detailed description of the second fingerprint sensing cycle is omitted where appropriate.

Referring to Fig. 4, the configuration combinations related to the second fingerprint sensing cycle of Fig. 4 are shown in Table 2 below. The sensing unit 120 is set to a negative integration configuration (marked as "-" in FIG. 4) to charge the node n0 that provides a common sensing result, and the sensing unit 122 is set to a negative integration configuration ( It is marked as "-" in Figure 4) to charge the node n0 that provides a common sensing result.

Table 2

It can be seen from Table 1 and Table 2 that the configuration combination related to the second fingerprint sensing cycle is different from the configuration combination related to the first fingerprint sensing cycle.

<Second Sensing Operation>

Referring to FIG. 4 supplemented by FIG. 11, the operation method 40 proceeds to operation 404, in which a second sensing operation is performed. The second sensing operation is described in detail below.

Referring to FIG. 4 supplemented by operation 500 of FIG. 12, the switch 144 is not turned on so that the conduction path between the sensing unit group 12 and the reading circuit 14 is not turned on.

Referring to FIG. 4 supplemented by operation 502 of FIG. 12, the sensing units 120 and 122 are exposed for the second time. When performing the second exposure, make the sensing unit 120 set to the negative integration configuration charge the node n0 to provide its own sensing result (charge+Q1) to the node n0; and make it set to be negative The node n0 is discharged to the sensing unit 122 in the integral configuration to provide its own sensing result (charge+Q2) to the node n0. Therefore, the node n0 is simultaneously affected by the sensing results of the sensing units 120 and 122 and correspondingly generates a common sensing result.

<Second reading operation>

Referring to FIG. 4 supplemented by FIG. 11, the operation method 40 proceeds to operation 406, and in operation 406, a second reading operation is performed. The second reading operation is described in detail below.

Referring to FIG. 4 supplemented by operation 600 of FIG. 13, the switch 144 is turned on to enable conduction between the sensing unit group 12 and the reading circuit 14.

Referring to FIG. 4 supplemented with operation 602 of FIG. 13, since the sensing units 120 and 122 both provide positive charges, charge +Q1 and charge +Q2. Therefore, the sensing units 120 and 122 charge the capacitor 142 of the reading circuit 14 according to the common sensing result on the node n0.

The calculation unit 30 stores the voltage of the output terminal of the amplifier 140 in the second fingerprint sensing cycle.

The operation method 40 proceeds to operation 408. Since all the sensing operations and reading operations have been performed, the operation method 40 proceeds to operation 410.

In operation 410, the calculation unit 30 is related to the common sensing result obtained under the first fingerprint sensing cycle, the common sensing result obtained under the second fingerprint sensing cycle, and the first fingerprint sensing cycle. The configuration combination of, and the configuration combination related to the second fingerprint sensing cycle are used to calculate the magnitudes of the charges Q1 and Q2 of the sensing results of the sensing units 120 and 122.

In detail, in the first fingerprint sensing cycle, the operator can know that the sensing unit 120 charges the node n0, and therefore can know that the polarity of the charge of the sensing result provided by the sensing unit 120 is positive, but does not know The magnitude of the charge of the sensing result provided by the sensing unit 120. In the same way, the operator can know that the sensing unit 122 is discharging the node n0, and therefore can know that the polarity of the sensing result provided by the sensing unit 122 is negative, but does not know the charge of the sensing result provided by the sensing unit 122 The amplitude. The calculation unit 30 stores the voltage of the output terminal of the amplifier 140 in the first fingerprint sensing cycle.

Similar to the first fingerprint sensing cycle, in the second fingerprint sensing cycle, the operator can know that the sensing unit 120 charges the node n0, and therefore can know the polarity of the charge of the sensing result provided by the sensing unit 120 Is positive, but the magnitude of the charge of the sensing result provided by the sensing unit 120 is unknown. In the same way, the operator can know that the sensing unit 122 is charging the node n0, and therefore can know that the polarity of the charge of the sensing result provided by the sensing unit 122 is positive, but does not know the charge of the sensing result provided by the sensing unit 122 The amplitude. The calculation unit 30 stores the voltage of the output terminal of the amplifier 140 in the second fingerprint sensing cycle.

Since we know the polarity of the charge provided by the sensing unit 120 and the sensing unit 122 related to the first sensing operation, the voltage related to the output terminal of the amplifier 140 in the first fingerprint sensing cycle, and the second The polarity of the charge provided by the sensing unit 120 and the sensing unit 122 of the second sensing operation and the voltage at the output terminal of the amplifier 140 in the second fingerprint sensing cycle can be used by the calculation unit 30, such as inverse matrix In this way, the magnitude of the charge provided by the sensing unit 120 and the sensing unit 122 is decoded. Accordingly, the sensitivity of each sensing unit 120 and 122 of the under-screen sensor of the handheld device (see the handheld device 50 in FIG. 15) can be relatively accurately determined.

FIG. 5 is a circuit diagram of each sensing unit 120 and 122 of the sensing unit group 12 in FIG. 2. 5, each of the sensing units 120 and 122 includes a photodiode 16, a capacitor 18, a first switch component including a first sub switch 71 and a second sub switch 72, a third sub switch 81 and a fourth sub switch 82 The second switch assembly and the read switch 19.

The photodiode 16 and the capacitor 18 are connected in parallel with the read switch 19.

The read switch 19 is controlled by the read line CR to make the conduction path to the output node n_out conductive or non-conductive, wherein the read switch 19 is conductive during the fingerprint sensing cycle.

The first switch element and the second switch element are controlled by the first control line CST1 and the second control line CST2 and are not turned on at the same time.

The first switch element is controlled by the first control line CST1 to control the cathode of the photodiode 16 to be coupled to the conduction path of the capacitor 142 of the reading circuit 14 via the output node n_out, and to control the anode of the photodiode 18 to be coupled to the first The conduction path of the voltage V1. In detail, the first sub-switch 71 of the first switch component is coupled between the cathode of the photodiode 16 and the capacitor 142 of the reading circuit 14, wherein the capacitor 142 of the reading circuit 14 is coupled to the output node n_out. Accordingly, the first switch component controls the conduction path of the cathode of the photodiode 16 coupled to the capacitor 142 of the reading circuit 14 through the first sub-switch 71. In addition, the second sub switch 72 of the first switch component is coupled between the anode of the photodiode 16 and the first voltage V1. Accordingly, the first switch component controls the anode of the photodiode 18 to be coupled to the conduction path of the first voltage V1 through the second sub-switch 72.

The second switch component is controlled by the second control line CST2 to control the cathode of the photodiode 16 to be coupled to the conduction path of the second voltage V2, and to control the anode of the photodiode 16 to be coupled to the read circuit 14 via the output node n_out. The conduction path of the capacitor 142. In detail, the third sub-switch 81 of the second switch component is coupled between the cathode of the photodiode 16 and the second voltage V2. Accordingly, the second switch component controls the cathode of the photodiode 16 to be coupled to the conduction path of the second voltage V2 through the third sub-switch 81. In addition, the fourth sub-switch 82 of the second switch component is coupled between the anode of the photodiode 16 and the capacitor 142 of the reading circuit 14. Accordingly, the second switch component controls the conduction path through which the anode of the photodiode 16 is coupled to the capacitor 142 of the reading circuit 14 through the fourth sub-switch 82.

Taking the sensing unit 120 as an example, in the sensing operation of operation 406, the read switch 19 is turned on. When the sensing unit 120 is set to a negative integration configuration, the first sub-switch 71 and the second sub-switch 72 are not conductive, and the third sub-switch 81 and the fourth sub-switch 82 are conductive. Accordingly, the cathode of the photodiode 16 is coupled to the second voltage V2 through the turned-on third sub-switch 81, and the anode of the photodiode 16 is coupled to the node n0 through the turned-on fourth sub-switch 82, so that the photodiode 16 The node n0 that provides the common sensing result is charged. Alternatively, when the sensing unit 120 is set to the forward integration configuration, the first sub switch 71 and the second sub switch 72 are turned on and the third sub switch 81 and the fourth sub switch 82 are not turned on. Accordingly, the cathode of the photodiode 16 is coupled to the node n0 through the turned-on first sub-switch 71, and the anode of the photodiode 16 is coupled to the first voltage V1 through the turned-on second sub-switch 72, so that the photodiode 16 Discharge the node n0 that provides the common sensing result.

6 is a circuit diagram of an equivalent circuit of the sensing unit group 12 of FIG. 2 under the first fingerprint sensing cycle. 6, the sensing unit 120 is set to a negative integration configuration, so that the photocurrent I1 generated by the photodiode 16 of the sensing unit 120 charges the node n0. In addition, the sensing unit 122 is configured in a forward integration configuration, so that the photocurrent I2 generated by the photodiode 16 of the sensing unit 122 is discharged to the node n0.

The photocurrent I1 provided by the sensing unit 120 can flow in the opposite direction to the photocurrent I2 provided by the sensing unit 122. In addition, the photodiode 16 of the sensing unit 120 and the photodiode 16 of the sensing unit 122 are essentially the same in semiconductor structure, so the photocurrent I1 provided by the photodiode 16 of the sensing unit 120 is ideally the same as that of the sensing unit 122. The photocurrent I2 provided by the photodiode 16. Therefore, the photocurrents I1 and I2 can effectively cancel each other. After offsetting, there is substantially no current to charge or discharge node n0. The change in the voltage of node n0 is relatively insignificant. Therefore, the change of the reverse bias voltage of the photodiode 16 of each sensing unit 120 and 122 is relatively insignificant, so that the photoelectric conversion efficiency is relatively not adversely affected, thereby improving linearity. Therefore, when the sensing units 120 and 122 are applied to under-screen sensors, the accuracy can be improved.

<Second Embodiment>

7 to 9 are schematic diagrams of the sensing unit group 22 of the second embodiment of the sensing unit matrix 13 of the thin film semiconductor structure 10 of the image sensor 15 in FIG. 1. Since the operation method of the sensing unit group 22 in FIGS. 7 to 9 is similar to the operation method of the sensing unit group 12 in FIGS. 3 to 4, the detailed description of the operation method of the sensing unit group 22 is omitted where appropriate.

FIG. 7 is a schematic diagram of the sensing unit group 22 of the second embodiment of the sensing unit matrix 13 of the thin-film semiconductor structure 10 of the image sensor 15 in FIG. 1. Referring to FIG. 7, the sensing unit group 22 is similar to the sensing unit group 12 of FIG. 2, the difference is that the sensing unit group 22 includes sensing units 120, 122 and 124.

The sensing unit group 22 has three sensing units 120, 122, and 124. Therefore, it is determined that the number of sensing operations and the number of reading operations is three, that is, it is determined that the cycle of three fingerprint sensing must be completed, so the sensing operation and the reading operation are repeated three times, as shown in FIG. 7 The first sensing operation and the first reading operation (that is, the first fingerprint sensing cycle), the second sensing operation and the second reading operation (that is, The second fingerprint sensing cycle), and the third sensing operation and the third reading operation (that is, the third fingerprint sensing cycle) as shown in FIG. 9 are respectively described in detail as follows.

<First fingerprint sensing loop>

Referring to FIG. 7 supplemented by operation 402 of FIG. 11, operation 402 further includes: setting the number of sensing units configured for the forward integration among the plurality of sensing units at least greater than zero; The number of sensing units configured for the negative integration in the sensing unit is at least greater than zero; the number of sensing units set to the positive integration configuration is different from the number of sensing units set to the negative integration The number of configured sensing units.

Referring to Fig. 7, the configuration combinations related to the first fingerprint sensing cycle of Fig. 7 are shown in Table 3 below. The sensing unit 120 is set to a negative integration configuration (marked as "-" in Figure 7) to charge the node n0 that provides a common sensing result, and the sensing unit 122 is set to a negative integration configuration (Figure 7). 7 is marked as "-") to charge the node n0 that provides a common sensing result, and the sensing unit 124 is set to a forward integration configuration (marked as "+" in FIG. 7) to provide common sensing The resulting node n0 is discharged.

The sensing units 120 and 122 are set to a negative integration configuration. Therefore, the number of sensing units set to a negative integration configuration is two, which is greater than zero. The sensing unit 124 is set to the forward integration configuration, therefore, the number of the sensing units set to the forward integration configuration is one, which is greater than zero. Furthermore, the number of sensing units set to the negative integration configuration is different from the number of sensing units set to the positive integration configuration. In this embodiment, the number of sensing units set in the negative integration configuration is more than the number of sensing units set in the positive integration configuration. However, the present disclosure is not limited to this. In some embodiments, the number of sensing units set in a negative integration configuration is less than the number of sensing units set in a positive integration configuration.

table 3

<First sensing operation>

Referring to FIG. 7 supplemented by FIG. 11, the operation method 40 proceeds to operation 404, in which the first sensing operation is performed. The first sensing operation is described in detail below.

Referring to FIG. 7 in conjunction with operation 500 of FIG. 12, the switch 144 is not turned on so that the conduction path between the sensing unit group 12 and the reading circuit 14 is not turned on.

Referring to FIG. 7 supplemented by operation 502 of FIG. 12, during the first exposure, the sensing unit 120 charges the node n0 to provide its own sensing result (charge+Q1) to the node n0; the sensing unit 122 charges the node n0 To provide its own sensing result (charge+Q2) to the node n0; and, the sensing unit 124 discharges the node n0 to provide its own sensing result (charge-Q3) to the node n0. Therefore, the node n0 will be simultaneously affected by the sensing results of the sensing units 120 and 122 and correspondingly generate a common sensing result

<First read operation>

Referring to FIG. 7 supplemented by FIG. 11, the operation method 40 proceeds to operation 406, in which the first reading operation is performed. The following details the first read operation.

Referring to FIG. 7 supplemented by operation 600 of FIG. 13, the switch 144 is turned on to turn on the conduction path between the sensing unit group 12 and the reading circuit 14.

Referring to FIG. 7 supplemented by operation 602 of FIG. 13, the sensing units 120, 122, and 124 charge the capacitor 142 of the reading circuit 14 according to the common sensing result on the node n0.

The calculation unit 30 stores the voltage of the output terminal of the amplifier 140 in the first fingerprint sensing cycle.

The operation method 40 proceeds to operation 408. Since all the sensing operations and reading operations have not been completed, the operation method 40 returns to operation 402 to perform the second fingerprint sensing cycle.

<Second fingerprint sensing loop>

FIG. 8 is a schematic diagram of the operation of the sensing unit group 22 and the reading circuit 14 of the image sensor 15 in FIG. 7 in the second fingerprint sensing cycle. Referring to FIG. 8, the configuration combinations related to the second fingerprint sensing cycle of FIG. 8 are shown in Table 4 below. Operation 402 of FIG. 11 further includes: each of the multiple configuration combinations generated by repeatedly performing the operation of setting the configuration combination of the sensing unit group has the same number of the negative integral configuration Sensing units, and the same number of sensing units in the forward integration configuration. Therefore, in the embodiment of FIG. 8, the number of sensing units set to a negative integration configuration remains two, and the number of sensing units set to a positive integration configuration remains one. In addition, operation 402 in FIG. 11 further includes: each time the configuration combination of the sensing unit group is set to be different from each other. In this embodiment, the sensing unit set to the forward integration configuration rotates among the sensing units 120, 122, and 124. In the embodiment of FIG. 8, the sensing unit set to the forward integration configuration is rotated to the sensing unit 122.

The sensing unit 120 is set to a negative integration configuration (marked as "-" in Figure 8) to charge the node n0 that provides a common sensing result, and the sensing unit 122 is set to a positive integration configuration (Figure 8). 8 is marked as "+") to discharge the node n0 that provides a common sensing result, and the sensing unit 122 is set to a negative integration configuration (marked as "-" in FIG. 8) to provide common sensing The resulting node n0 is charged.

Table 4

It can be seen from Table 3 and Table 4 that the configuration combination related to the second fingerprint sensing cycle is different from the configuration combination related to the fingerprint sensing cycle.

<Second Sensing Operation>

Referring to FIG. 8 supplemented with FIG. 11, the operation method 40 proceeds to operation 404, and in operation 404, a second sensing operation is performed. The second sensing operation is described in detail below.

Referring to FIG. 8 in conjunction with operation 500 of FIG. 12, the switch 144 is not turned on so that the conduction path between the sensing unit group 12 and the reading circuit 14 is not turned on.

Referring to FIG. 8 supplemented by operation 502 of FIG. 12, during the second exposure, the sensing unit 120 charges the node n0 to provide its own sensing result (charge + Q1) to the node n0; the sensing unit 122 discharges the node n0 To provide its own sensing result (charge-Q2) to node n0; and, the sensing unit 124 charges the node n0 to provide its own sensing result (charge+Q3) to node n0. Therefore, the node n0 will be simultaneously affected by the sensing results of the sensing units 120, 122 and 124 and correspondingly generate a common sensing result

<Second reading operation>

Since the operation mode of the second read operation is the same as the operation mode of the first read operation, it will not be repeated here.

The calculation unit 30 stores the voltage of the output terminal of the amplifier 140 in the second fingerprint sensing cycle.

The operation method 40 proceeds to operation 408. Since all the sensing operations and reading operations have not been completed, the operation method 40 returns to operation 402 to perform the third sensing operation and the third reading operation.

<Third fingerprint sensing loop>

9 is a schematic diagram of the operation of the sensing unit group 22 and the reading circuit 14 of the image sensor 15 in FIG. 7 in the third fingerprint sensing cycle. Referring to FIG. 9, the configuration combinations related to the third fingerprint sensing cycle of FIG. 9 are shown in Table 5 below. In Figure 9, the sensing unit set to the forward integration configuration is rotated to the sensing unit 120

The sensing unit 120 is set to a positive integration configuration (marked as "+" in Figure 9) to discharge the node n0 that provides a common sensing result, and the sensing unit 122 is set to a negative integration configuration (Figure 9). 9 marked as "-") to charge the node n0 that provides a common sensing result, and the sensing unit 122 is set to a negative integration configuration (marked as "-" in FIG. 9) to provide common sensing The resulting node n0 is charged.

table 5

<The third sensing operation>

Referring to FIG. 9 supplemented with FIG. 11, the operation method 40 proceeds to operation 404, and in operation 404, a third sensing operation is performed. The third sensing operation is described in detail below.

9 with reference to operation 500 of FIG. 12, the switch 144 is not turned on so that the conduction path between the sensing unit group 12 and the reading circuit 14 is not turned on.

Referring to FIG. 9 supplemented by operation 502 of FIG. 12, during the third exposure, the sensing unit 120 discharges the node n0 to provide its own sensing result (charge-Q1) to the node n0; the sensing unit 122 charges the node n0 To provide its own sensing result (charge+Q2) to node n0; and, the sensing unit 124 charges the node n0 to provide its own sensing result (charge+Q3) to node n0. Therefore, the node n0 will be simultaneously affected by the sensing results of the sensing units 120, 122 and 124 and correspondingly generate a common sensing result

<Third reading operation>

Since the operation mode of the third reading operation is the same as the operation mode of the first reading operation, it will not be repeated here.

The calculation unit 30 stores the voltage of the output terminal of the amplifier 140 during the third sensing operation and the third reading operation.

The operation method 40 proceeds to operation 408. Since all the sensing operations and reading operations have been performed, the operation method 40 proceeds to operation 410.

In operation 410, the calculation unit 30 is based on the common sensing result obtained in the first fingerprint sensing cycle, the common sensing result obtained in the second fingerprint sensing cycle, and the common sensing result obtained in the third fingerprint sensing cycle. Calculated by the obtained common sensing result, the configuration combination related to the first fingerprint sensing cycle, the configuration combination related to the second fingerprint sensing cycle, and the configuration combination related to the third fingerprint sensing cycle The magnitudes of the charges Q1, Q2, and Q3 of the sensing results of the sensing units 120, 122, and 124 are obtained.

FIG. 10 is a circuit diagram of an equivalent circuit of the sensing unit group 22 of FIG. 7 under the first fingerprint sensing cycle. 10, similar to the illustration in FIG. 6, the sensing unit 120 is set to a negative integration configuration, and the photocurrent I1 provided by the sensing unit 120 flows into node n0; the sensing unit 122 is set to negative To the integration configuration, the photocurrent I2 provided by the sensing unit 122 flows into the node n0; and, the sensing unit 124 is set to the forward integration configuration, and the photocurrent I3 provided by the sensing unit 124 flows from the node n0.

The photocurrent I1 provided by the sensing unit 120 and the photocurrent I2 provided by the sensing unit 122 both flow in opposite directions to the photocurrent I3 provided by the sensing unit 124. Either photocurrent I1 and I2 is ideally the same as photocurrent I3. Therefore, either of the photocurrents I1 and I2 can effectively offset the photocurrent I3. Accordingly, the change of the reverse bias voltage of the photodiode 16 of each sensing unit 120, 122, 124 is relatively insignificant, so that the photoelectric conversion efficiency is relatively not adversely affected, thereby improving linearity. Therefore, when the sensing units 120, 122, 124 are applied to under-screen sensors, the accuracy can be improved.

In addition, it is assumed that the photocurrent I1 and the photocurrent I3 effectively offset, but there is still the photocurrent I2. However, because the sensing unit 120 and the sensing unit 122 are both set to a negative integration configuration, the capacitor 18 of the sensing unit 120 and the capacitor 18 of the sensing unit 122 are connected in parallel with respect to the node n0. Since the equivalent capacitance of the two capacitors in parallel is greater than the capacitance of a single capacitor, the equivalent capacitance of the node n0 is greater than the capacitance of the capacitor 18 of the single sensing unit 120 or the capacitance of the capacitor 18 of the single sensing unit 122. Accordingly, even if there is a photocurrent I2, the equivalent capacitance charged by the photocurrent I2 is relatively large, so the change in the voltage of the node n0 is relatively insignificant, so that the photodiode 16 of each sensing unit 120, 122, 124 is The change of the reverse bias voltage is relatively insignificant, so it does not adversely affect the photoelectric conversion efficiency, thereby improving linearity. Therefore, when the sensing units 120, 122, 124 are applied to under-screen sensors, the accuracy can be improved.

FIG. 14 is a schematic diagram of an embodiment of the handheld device 50 of this application. The handheld device 50 includes a display screen assembly 52 and an image sensor 15. The handheld device 50 can be used for optical under-screen fingerprint sensing to sense the fingerprint of a specific object. The handheld device 50 can be any handheld electronic device such as a smart phone, a personal digital assistant, a handheld computer system, or a tablet computer.

FIG. 15 is a cross-sectional view of an embodiment of the handheld device 50 of FIG. 14. 15, the display screen assembly 52 includes a display panel 54 and a protective cover 56. The display panel 54 has a first side and a second side opposite to the first side. The protective cover 56 is disposed on the second side of the display panel 54, that is, the protective cover 56 is disposed above the display panel 54. The thin film semiconductor structure 10 is disposed on the first side of the display panel 54, that is, the thin film semiconductor structure 10 is disposed under the display panel 54 so that the display panel 54 is located between the thin film semiconductor structure 10 and the protective cover 56. In this embodiment, the display panel 54 may be an organic electroluminescent display panel (OLED), but is not limited to this.

The above description briefly presents the features of certain embodiments of the present application, so that those with ordinary knowledge in the technical field to which the present application belongs can more fully understand the various aspects of the present disclosure. Those who have ordinary knowledge in the technical field to which this application belongs can 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 as the embodiments described herein. To achieve the same advantages. Those with ordinary knowledge in the technical field to which this application belongs should understand that these equal implementations still belong to the spirit and scope of the disclosure, and various changes, substitutions and alterations can be made without departing from the spirit of the disclosure. With scope.

Claims (17)

A thin film semiconductor structure is coupled to a reading circuit outside the thin film semiconductor structure, the reading circuit includes a capacitor, and is characterized in that the thin film semiconductor structure includes: Substrate; and The sensing unit group is configured on the substrate, the sensing unit group and the reading circuit are operated together in a sensing operation or a reading operation, and the sensing unit group includes a plurality of sensing units, Each of the sensing units can be set to a positive integration configuration or a negative integration configuration under the sensing operation to generate a common sensing result, wherein the multiple sensing units are under the reading operation The capacitor of the reading circuit is charged or discharged according to the common sensing result. The thin film semiconductor structure of claim 1, wherein each of the sensing units includes a photodiode. 3. The thin film semiconductor structure of claim 2, wherein each of the sensing units further comprises: A capacitor in parallel with the photodiode; A first switch component for controlling the conduction path where the cathode of the photodiode is coupled to the capacitor of the reading circuit and the conduction path where the anode of the photodiode is coupled to the first voltage; and The second switch component is used to control the conduction path of the cathode of the photodiode being coupled to the second voltage and the conduction path of the capacitor of the photodiode coupled to the reading circuit, wherein The first voltage is lower than the second voltage. The thin film semiconductor structure according to claim 3, Wherein the first switch component includes: The first sub-switch is coupled between the cathode of the photodiode and the capacitor of the reading circuit; and The second sub-switch is coupled between the anode of the photodiode and the first voltage; Wherein the second switch assembly includes: The third sub switch is coupled between the cathode of the photodiode and the second voltage; and The fourth sub switch is coupled between the anode of the photodiode and the capacitor of the reading circuit. The thin film semiconductor structure of claim 4, wherein when the sensing unit is set to the negative integration configuration, the first sub switch and the second sub switch are not conductive and the The third sub switch and the fourth sub switch are turned on, so that the photodiode charges the node that provides the common sensing result. The thin film semiconductor structure of claim 4, wherein when the sensing unit is set to the forward integration configuration, the first sub switch and the second sub switch are turned on and the first The three sub-switches and the fourth sub-switch are not turned on, so that the photodiode discharges the node that provides the common sensing result. An operating method for operating the thin film semiconductor structure according to any one of claims 1-6, wherein the operating method comprises: Performing the sensing operation includes: Making the conduction path between the sensing unit group and the reading circuit non-conductive, and exposing the photodiodes of the plurality of sensing units to generate the common sensing result; and Performing the read operation includes: The sensing unit group and the reading circuit are turned on, and the plurality of sensing units are caused to charge or discharge the capacitor of the reading circuit according to the common sensing result. The operation method according to claim 7, further comprising: The number of operations of the sensing operation and the reading operation is determined according to the number of the plurality of sensing units, wherein the operation method further includes: According to the number of operations, the sensing operation and the reading operation are repeatedly performed. 8. The operation method of claim 8, wherein the number of operations is the same as the number of the plurality of sensing units. The operation method according to claim 9, further comprising: Before performing the sensing operation, setting the configuration combination of the sensing unit group, wherein the operation of setting the configuration combination of the sensing unit group includes: Setting each sensing unit to the positive integration configuration or the negative integration configuration; and The operation of causing the plurality of sensing units to charge or discharge the capacitor of the reading circuit according to the common sensing result includes: Charging the sensing unit set to the negative integration configuration to the node of the capacitor coupled to the reading circuit; and Discharge the node by the sensing unit set to the forward integration configuration. The operation method of claim 10, wherein the operation of setting the positive integration configuration or the negative integration configuration of each sensing unit comprises: Setting the number of sensing units configured for the forward integration among the plurality of sensing units to be at least greater than zero; and The number of the sensing units configured for the negative integration among the plurality of sensing units is set to be at least greater than zero. 11. The operation method of claim 11, wherein the number of sensing units set in the positive integration configuration is different from the number of sensing units set in the negative integration configuration. The operation method of claim 12, wherein the operation of repeatedly performing the sensing operation and the reading operation according to the number of operations includes: The operation of setting the configuration combination of the sensing unit group, the sensing operation, and the reading operation are repeatedly performed, wherein the configuration combination of setting the sensing unit group is different from each other each time. The operation method according to claim 13, wherein each of the plurality of configuration combinations generated by repeatedly performing the operation of setting the configuration combination of the sensing unit group has the same number of the negative points Configured sensing units, and the same number of sensing units in the forward integration configuration. The operation method according to claim 14, further comprising: Calculated based on repeated execution of the operation of setting the configuration combination of the sensing unit group, multiple common sensing results generated by the sensing operation and the reading operation, and the multiple configuration combinations The respective sensing results of the multiple sensing units are obtained. A handheld device with fingerprint sensing function for sensing fingerprints of a specific object, characterized in that the handheld device includes: Display assembly; and The thin film semiconductor structure according to any one of claims 1-6. The handheld device according to claim 16, wherein the display screen assembly comprises a display panel and a protective cover, the display panel has a first side and a second side opposite to the first side, the The protective cover is disposed on the second side of the display panel, and the thin film semiconductor structure is disposed on the first side of the display panel, so that the display panel is located between the thin film semiconductor structure and the protective cover .

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