WO2019127577A1

WO2019127577A1 - Optical sensing method for photosensitive device

Info

Publication number: WO2019127577A1
Application number: PCT/CN2017/120405
Authority: WO
Inventors: 李问杰
Original assignee: 深圳信炜科技有限公司
Priority date: 2017-12-30
Filing date: 2017-12-30
Publication date: 2019-07-04
Also published as: CN108124484A; CN108124484B

Abstract

An optical sensing method for a photosensitive device, the photosensitive device (20) comprising a plurality of photosensitive pixels (22), said method comprising: providing a first scanning driving signal and a second scanning driving signal for all the photosensitive pixels (22), so that all the photosensitive pixels (22) start to perform optical sensing when a first predetermined time arrives and stop performing optical sensing when a third predetermined time arrives, so as to latch electrical signals generated by the photosensitive pixels (22) when performing optical sensing; and when all the photosensitive pixels (22) have stopped performing optical sensing, successively providing output control signals for the plurality of photosensitive pixels (22), so as to control the output of the latched electrical signals corresponding to the plurality of photosensitive pixels (22).

Description

Photosensitive method of photosensitive device

Technical field

The present invention relates to a light sensing method for a photosensitive device for sensing biometric information.

Background technique

At present, fingerprint recognition has gradually become a standard component of electronic products such as mobile terminals. Since optical fingerprint recognition has stronger penetrability than capacitive fingerprint recognition, the application of optical fingerprint recognition to mobile terminals is a future development trend. However, the existing optical fingerprint recognition structure applied to mobile terminals still needs to be improved.

Summary of the invention

The embodiments of the present invention aim to at least solve one of the technical problems existing in the prior art. Therefore, embodiments of the present invention need to provide a photosensitive device, a light sensing method thereof, and an electronic device.

A light sensing method of a photosensitive device according to an embodiment of the present invention, the photosensitive device includes a plurality of photosensitive pixels, wherein the light sensing method comprises the following steps:

Providing a first scan driving signal and a second scan driving signal to all of the photosensitive pixels such that all of the photosensitive pixels start performing light sensing when the first predetermined time arrives, and ending performing light sensing when the third predetermined time arrives, Latching an electrical signal generated when performing light sensing on the photosensitive pixel;

After all the photosensitive pixels finish performing the light sensing, an output control signal is sequentially provided to the plurality of photosensitive pixels to control the latched electrical signal output corresponding to the plurality of photosensitive pixels.

The photosensitive driving circuit of the embodiment of the present invention drives all the photosensitive pixels of the photosensitive device to simultaneously perform light sensing, and controls all the photosensitive speed limit ends to perform light sensing to lock the electrical signals generated when the photosensitive pixels perform light sensing. Save, giving the output control of the light signal enough time and flexibility. Moreover, the control timing of the photosensitive pixels in the photosensitive device is simple, and the photosensitive time is short, thereby improving the sensing speed. In addition, all the photosensitive pixels perform light sensing at the same time, thereby avoiding the influence of the movement of the object on the light sensing, thereby resisting the image distortion ability, thereby improving the sensing precision.

In some embodiments, the plurality of photosensitive pixels are arranged in an array; and after the step of performing the light sensing, the step of sequentially providing the output control signal to the plurality of photosensitive pixels comprises:

After all the photosensitive pixels finish performing the light sensing, the output control signals are provided to the plurality of photosensitive pixels row by row or interlaced until the latched electrical signals corresponding to all the photosensitive pixels are output. The output control signal is supplied to the second scan line row by row or interlaced, thereby realizing the output of the entire line of the photosensitive signal, thereby improving the sensing speed.

After all the photosensitive pixels finish performing the light sensing, the output control signals are provided row by row to the plurality of photosensitive pixels from beginning to end according to the distribution order of the plurality of photosensitive pixels, and then provided from the end to the top by line. The output control signal is sent to the plurality of photosensitive pixels to accumulate the electrical signals that are output twice to obtain a final electrical signal.

The embodiment of the invention can output the photosensitive signal twice, so that the photosensitive signal can be read twice, thereby balancing the readout waiting time of different photosensitive pixels, thereby solving the influence of charge leakage on the photosensitive signal collection, and improving the effect. Sensing accuracy.

In some embodiments, the step of sequentially providing the output control signal to the plurality of photosensitive pixels after the photo sensing is completed by all the photosensitive pixels includes:

After all the photosensitive pixels finish performing the light sensing, the output control signals are provided to the plurality of photosensitive pixels point by point according to the distribution order of the plurality of photosensitive pixels. In this way, the electrical signal latched by the photosensitive pixel is outputted point by point, so that the signal reading channel can be set one, thereby saving the cost of the photosensitive device.

In some embodiments, the photosensitive pixel includes a photosensitive unit and a switching unit electrically connected to the photosensitive unit, and the photosensitive unit includes at least one photosensitive device and a first capacitor, and the switching unit includes the first a switch and a third switch; the step of providing the first scan driving signal and the second scan driving signal to all the photosensitive pixels further comprises:

Providing the first scan driving signal to the first switch of all the photosensitive pixels while providing a second scan driving signal to the third switch of all the photosensitive pixels to control the first switch and the third switch of all the photosensitive pixels Closing, and when the first predetermined time arrives, controlling the first switch to be turned off, the photosensitive unit starts performing light sensing; and when the third predetermined time arrives, controlling the third switch to be turned off, the light sensing The unit ends performing light sensing.

In some embodiments, the photosensitive pixel further includes a signal output unit electrically connected to the photosensitive unit, the signal output unit includes a second switch; after all the photosensitive pixels finish performing light sensing, The step of sequentially providing an output control signal to the plurality of photosensitive pixels further includes:

After the third switch of the switch unit is turned off, the output control signal is sequentially supplied to the second switch to control the second switch of the signal output unit to be closed, and the photosensitive unit in the photosensitive pixel is output to perform light. The electrical signal generated during sensing.

In some embodiments, the photosensitive pixel includes a photosensitive unit and a switch unit electrically connected to the photosensitive unit; the photosensitive unit includes at least one photosensitive device, a first capacitor and a second capacitor, and the switch unit includes The fourth switch, the fifth switch, and the seventh switch; the step of providing the first scan driving signal and the second scan driving signal to all the photosensitive pixels further includes:

Providing the first scan driving signal to the fourth switch and the fifth switch of all the photosensitive pixels while providing a second scan driving signal to the seventh switch of all the photosensitive pixels to control the fourth switch of all the photosensitive pixels And the fifth switch and the seventh switch are closed, and when the first predetermined time arrives, the fourth switch and the fifth switch are controlled to be turned off, the photosensitive unit starts to perform light sensing; when the third predetermined time arrives, The seventh switch is controlled to be turned off, the photosensitive unit ends performing light sensing, and the first capacitance latches an electrical signal generated when the photosensitive unit performs light sensing.

In some embodiments, the photosensitive pixel further includes a signal output unit electrically connected to the photosensitive unit, the signal output unit includes a sixth switch and a conversion circuit; the end of performing light perception at all of the photosensitive pixels After the measurement, the step of sequentially controlling the output of the electrical signals generated when the plurality of photosensitive pixels perform photo sensing further comprises:

After the seventh switch of the switch unit is turned off, the output control signal is sequentially provided to the sixth switch to control the sixth switch of the signal output unit to be closed, so that the conversion circuit receives a constant electrical signal. And converting the constant electrical signal into two different electrical signals according to an electrical signal latched by the photosensitive unit, and outputting.

In some embodiments, the third predetermined time is dynamically adjusted based on the intensity of the received optical signal.

In some embodiments, the greater the intensity of the received optical signal, the shorter the third predetermined time; the smaller the intensity of the received optical signal, the longer the third predetermined time.

The embodiment of the invention adjusts the reading time of the electrical signal generated by the photosensitive pixel in time according to the intensity of the optical signal, thereby ensuring accurate reading of the electrical signal, thereby improving the sensing accuracy.

In certain embodiments, the constant electrical signal is a constant current signal.

In some embodiments, the light sensing method further comprises:

Predetermining biometric information of an object contacting or approaching the photosensitive device is acquired based on the electrical signals generated when the plurality of photosensitive pixels are read to perform light sensing.

Additional aspects and advantages of the embodiments of the invention will be set forth in part in

DRAWINGS

The above and/or additional aspects and advantages of the embodiments of the present invention will become apparent and readily understood from

1 is a schematic view showing an array distribution of photosensitive pixels in a photosensitive device according to an embodiment of the present invention;

2 is a schematic diagram showing the circuit structure of an embodiment of the photosensitive pixel shown in FIG. 1;

3 is a timing diagram of signals at respective nodes when the photosensitive pixel shown in FIG. 2 performs light sensing;

4 is a structure of a connection relationship between a photosensitive pixel and a scanning line, a data line, and a signal reference line in the photosensitive device according to an embodiment of the present invention, and the photosensitive pixel is a photosensitive pixel structure shown in FIG. 2;

Figure 5 is a block diagram showing the structure of an embodiment of the photosensitive driving unit shown in Figure 4;

6 is a signal timing diagram of an embodiment in which the photosensitive device shown in FIG. 4 performs light sensing;

7 is a signal timing diagram of another embodiment in which the photosensitive device shown in FIG. 4 performs light sensing;

8 is a schematic circuit diagram of another embodiment of the photosensitive pixel shown in FIG. 1;

FIG. 9 is a timing chart of signals at each node when the photosensitive pixel shown in FIG. 8 performs light sensing; FIG.

FIG. 10 is a schematic diagram showing the circuit structure of still another embodiment of the photosensitive pixel shown in FIG. 1; FIG.

11 is a structure of a connection relationship between a photosensitive pixel and a scanning line, a data line, and a signal reference line in the photosensitive device according to an embodiment of the present invention, and the photosensitive pixel is a photosensitive pixel structure shown in FIG. 8;

Figure 12 is a block diagram showing the structure of an embodiment of the photosensitive driving unit shown in Figure 11;

FIG. 13 is a schematic structural view of a photosensitive panel in a photosensitive device according to an embodiment of the present invention; FIG.

14 is a schematic flow chart of a light sensing method of a photosensitive device according to an embodiment of the present invention;

15 is a schematic structural view of an electronic device to which a photosensitive device according to an embodiment of the present invention is applied;

16 is a cross-sectional view of an embodiment of the electronic device shown in FIG. 15 taken along line I-I, and FIG. 16 shows a partial structure of the electronic device;

17 is a schematic view showing a corresponding position of a display area of a display panel and a sensing area of the photosensitive panel according to an embodiment of the present invention;

18 is a cross-sectional view of another embodiment of the electronic device shown in FIG. 15 taken along line I-I, and FIG. 18 shows a partial structure of the electronic device.

Detailed ways

The embodiments of the present invention are described in detail below, and the examples of the embodiments are illustrated in the drawings, wherein the same or similar reference numerals indicate the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the drawings are intended to be illustrative of the invention and are not to be construed as limiting.

In the description of the present invention, it is to be understood that the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, features defining "first" or "second" may include one or more of the described features either explicitly or implicitly. In the description of the present invention, the meaning of "a plurality" is two or more unless specifically and specifically defined otherwise. "Contact" or "touch" includes direct or indirect contact.

In the description of the present invention, it should be noted that the terms "installation", "connected", and "connected" are to be understood broadly, and may be fixed or detachable, for example, unless otherwise explicitly defined and defined. Connected, or integrally connected; may be mechanically connected, or may be electrically connected or may communicate with each other; may be directly connected or indirectly connected through an intermediate medium, may be internal communication of two elements or interaction of two elements relationship. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood on a case-by-case basis.

The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of the specific examples are described below. Of course, they are merely examples and are not intended to limit the invention. In addition, the present invention may be repeated with reference to the numerals and/or reference numerals in the various examples, which are for the purpose of simplification and clarity, and do not indicate the relationship between the various embodiments and/or settings discussed. Moreover, the present invention provides examples of various specific processes and materials, but one of ordinary skill in the art will recognize the use of other processes and/or the use of other materials.

Further, the described features, structures may be combined in one or more embodiments in any suitable manner. In the following description, numerous specific details are set forth However, those skilled in the art will appreciate that the technical solution of the present invention can be practiced without one or more of the specific details or other structures, components, and the like. In other instances, well-known structures or operations are not shown or described in detail to avoid obscuring the invention.

Embodiments of the present invention provide a photosensitive device disposed in an electronic device, particularly disposed under a display screen of an electronic device. The display screen has a display device that emits an optical signal, such as, but not limited to, an OLED display panel. When the electronic device is working, the display emits an optical signal to perform the corresponding image display. At this time, if the target object touches or touches the electronic device, the light signal emitted by the display screen reaches the target object and reflects, and the reflected light signal passes through the display screen and is received by the photosensitive device, and the light receiving device receives the light signal. Converting to an electrical signal corresponding to the optical signal to form predetermined biometric information of the target object based on the electrical signal generated by the photosensitive device.

The biometric information of the target object is, for example but not limited to, skin texture information such as fingerprints, palm prints, ear prints, and soles, and other biometric information such as heart rate, blood oxygen concentration, and veins. The target object, such as but not limited to a human body, may also be other suitable types of objects.

In some embodiments, the electronic device can also provide a light source for biometric information sensing. When the electronic device performs biometric information sensing, the light source emits a corresponding optical signal, such as infrared light, to achieve sensing of heart rate, blood oxygen concentration, veins, and the like of the target object.

Electronic devices such as, but not limited to, suitable types of electronic products such as consumer electronics, home electronics, vehicle-mounted electronic products, and financial terminal products. Among them, consumer electronic products such as mobile phones, tablets, notebook computers, desktop monitors, computer integrated machines. Home-based electronic products such as smart door locks, TVs, refrigerators, wearable devices, etc. Vehicle-mounted electronic products such as car navigation systems, car DVDs, etc. Financial terminal products such as ATM machines, terminals for self-service business, etc.

Please refer to FIG. 1. FIG. 1 shows an array distribution structure of photosensitive pixels in a photosensitive device. The photosensitive device 20 includes a plurality of photosensitive pixels 22, and the plurality of photosensitive pixels 22 are arrayed in a matrix to form a photosensitive array 201. . Specifically, the photosensitive array 201 includes a plurality of rows of photosensitive pixels and a plurality of columns of photosensitive pixels, and each row of photosensitive pixels is spaced apart in the X direction, and each column of the photosensitive pixels is spaced apart in the Y direction. When the photosensitive device 20 performs image sensing, each row of the photosensitive pixels 22 can be driven to perform light sensing from the X direction, and the electrical signals generated by the respective photosensitive pixels 22 to perform light sensing can be read from the Y direction. Of course, each of the photosensitive pixels 22 forming the photosensitive array 201 is not limited to the vertical relationship shown in FIG. 1, and may be distributed in other regular manners or in an irregular manner.

In some embodiments, each photosensitive pixel 22 includes a sensing unit and a signal output unit. The sensing unit is configured to receive a light sensing control signal, perform light sensing when receiving the light sensing control signal, and generate a corresponding light sensing signal; the signal output unit is configured to receive an output control signal, And receiving the light sensing signal generated when the sensing unit performs light sensing when receiving the output control signal.

Specifically, referring to FIG. 2, FIG. 2 shows a circuit configuration of one photosensitive pixel 22 of FIG. 1. A photosensitive pixel 22 in the embodiment of the present invention has a first input terminal In1, a second input terminal In2, a third input terminal In3, a fourth input terminal In4, and a first output terminal Out1. The light sensing control signal includes a first scan driving signal and a second scan driving signal. The photosensitive pixel 22 includes a sensing unit and a signal output unit 223. The sensing unit further includes a switching unit 221 and a photosensitive unit 222. The photosensitive unit 222 is connected between the switching unit 221 and the signal output unit 223. The switch unit 221 receives a reference signal Vref through the third input terminal In3. In addition, the switch unit 221 further receives a first scan driving signal through the first input terminal In1, and receives a second scan driving through the fourth input terminal In4. And transmitting, when receiving the first scan driving signal and the second scan driving signal, the reference signal Vref to the photosensitive unit 222 to drive the photosensitive unit 222 to perform light sensing, and start performing light perception at the photosensitive unit 222 The light sensing is terminated after a predetermined time period, and the photosensitive signal generated by the light sensing by the photosensitive unit 222 is latched. The photosensitive unit 222 receives the optical signal and converts the received optical signal into a corresponding electrical signal upon receiving the optical signal. The signal output unit 223 receives the output control signal through the second input terminal In2, and outputs the electrical signal generated by the photosensitive unit 222 from the first output terminal Out1 according to the output control signal.

Optionally, the first scan driving signal and the second scan driving signal and the output control signal are both a pulse signal, and the duration of the high level signal in the first scan driving signal is a first predetermined time, and the output control signal is in a high level. The duration of the signal is a second predetermined time, the duration of the high level signal in the second scan driving signal is a third predetermined time, and the third predetermined time is greater than the first predetermined time.

In some embodiments, the photosensitive unit 222 includes a photosensitive device including a first electrode for receiving the reference signal Vref transmitted by the switching unit 221 and a second electrode for receiving A fixed electrical signal. A driving voltage for driving the photosensitive device is formed by applying a reference signal Vref and a fixed electrical signal to both electrodes of the photosensitive device. The photosensitive device is, for example but not limited to, a photodiode D1, which may alternatively be a photo resistor, a phototransistor, a thin film transistor or the like. It should be noted that the number of photosensitive devices may also be two, three, and the like. Taking photodiode D1 as an example, the photodiode D1 includes a positive electrode and a negative electrode, wherein the positive electrode receives a fixed electrical signal, such as a ground signal NGND; and the negative electrode serves as a first electrode of the photosensitive device for receiving the reference signal Vref transmitted by the switching unit 221. . It should be noted that as long as the reference signal Vref is applied to both ends of the photodiode D1 corresponding to the fixed electrical signal, a reverse voltage can be formed across the photodiode D1, thereby driving the photodiode to perform photo sensing.

When the switch unit 221 is closed, the reference signal Vref is transmitted to the negative terminal of the photodiode D1 through the closed switch unit 221, and since the photodiode D1 has an equivalent capacitance inside, the reference signal Verf performs the equivalent capacitance inside the photodiode D1. Charging, so that the voltage Vg on the negative electrode of the photodiode D1 gradually rises and reaches the first predetermined time, the voltage Vg reaches the voltage value of the reference signal Vref and remains unchanged. At this time, the voltage difference across the photodiode D1 will reach the reverse voltage at which the photodiode is driven, that is, the photodiode D1 is in operation. Since the first scan driving signal is turned from the high level to the low level when the first predetermined time is reached, the switching unit 221 is turned off, and a discharge loop is formed inside the photodiode D1. At this time, if an optical signal is incident on the photodiode D1, the reverse current of the photodiode D1 rapidly increases, so that the voltage Vg on the negative node of the photodiode D1 changes, that is, as the discharge time gradually decreases. Since the intensity of the optical signal is larger, the reverse current generated by the photodiode D1 is also larger, and the lowering speed of the voltage Vg on the negative node of the photodiode D1 is faster.

Further, the photosensitive unit 222 further includes a first capacitor c1. The first capacitor c1 is used to form a discharge loop with the photosensitive device when performing light sensing to obtain a corresponding photosensitive signal. Specifically, as shown in FIG. 2, the first capacitor c1 is disposed in parallel with the photosensitive device, that is, the first plate of the first capacitor c1 is connected to the cathode of the photodiode D1, and the second plate of the first capacitor c1 is grounded. When the reference signal Vref is transmitted to the negative electrode of the photodiode D1, the first capacitor c1 is also charged, and when the switch unit 221 is turned off, the first capacitor c1 forms a discharge loop with the photodiode D1, and the first capacitor c1 The voltage of one plate (ie, voltage Vg) also gradually decreases with discharge time. By setting the first capacitor c1, the capacitance capacity of the photosensitive unit 222 is increased, thereby reducing the voltage drop speed on the negative electrode of the photodiode D1, thereby ensuring that an effective photosensitive signal is obtained, and the sensing accuracy of the photosensitive device 20 on the target object is improved. .

Further, the first capacitor c1 is a variable capacitor, for example, a capacitor array formed by a plurality of capacitors, and the plurality of capacitors are disposed in parallel, and the capacity change of the first capacitor c1 is realized by controlling whether the plurality of capacitors are connected. Since the first capacitor c1 is set as a variable capacitor, the capacity adjustment of the first capacitor c1 is adapted to the change of the received optical signal, thereby obtaining an accurate and effective photosensitive signal. Specifically, if the intensity of the received optical signal is larger, the capacity of the first capacitor c1 is larger, and if the intensity of the received optical signal is smaller, the capacity of the first capacitor c1 is smaller.

In some embodiments, the switch unit 221 includes a first transistor T1 and a fourth transistor T4, such as but not limited to any one or several of a transistor, a MOS transistor, and a thin film transistor. . Taking the MOS transistor as an example, the first transistor T1 includes a first control electrode C1, a first transfer electrode S1, and a second transfer electrode S2, wherein the first control electrode is a gate of the MOS transistor, and the first transfer electrode S1 is a MOS transistor. The drain of the second transfer electrode S2 is the source of the MOS transistor. The fourth transistor T4 includes a fourth control electrode C4, a seventh transfer electrode S7 and an eighth transfer electrode S8, wherein the fourth control electrode C4 is the gate of the MOS transistor, and the seventh transfer electrode S7 is the drain of the MOS transistor, The eight transfer electrodes S8 are the sources of the MOS transistors.

Further, the first control electrode C1 is connected to the first input terminal In1 for receiving the first scan driving signal; the first transmitting electrode S1 is connected to the third input terminal In3 for receiving the reference signal Vref; and the second transmitting electrode S2 It is connected to the negative electrode of the photodiode D1 in the photosensitive unit 222. When the first scan driving signal is input through the first input terminal In1, the first transistor T1 is turned on according to the first scan driving signal, and the reference signal Vref is transmitted to the cathode of the photodiode D1 via the first transfer electrode S1 and the second transfer electrode S2. . The fourth control electrode C4 is connected to the fourth input terminal In4 for receiving the second scan driving signal; the seventh transfer electrode S7 is connected to the first electrode of the photosensitive device (for example, the negative electrode of the photodiode), and the eighth transfer electrode S8 and the A first plate of a capacitor c1 is connected. Moreover, the first plate of the first capacitor c1 is used to connect the signal output unit 223', that is, the first plate of the first capacitor c1 is connected to the third control electrode C3 of the third transistor T3. When the second scan driving signal is input through the fourth input terminal In4, the fourth transistor T4 is turned on according to the second scan driving signal, and the reference signal Vref is transmitted to the first pole of the first capacitor c1 via the first transistor T1 and the fourth transistor T4. board. Since the first scan driving signal turns to a low level signal when the first predetermined time arrives, the first transistor T1 is turned off, and at this time, the first capacitor c1 forms a discharge loop with the photodiode D1, and starts performing light sensing.

In some embodiments, signal output unit 223 includes a second transistor T2 and a buffer circuit. The snubber circuit is used to buffer the electrical signal generated by the photosensitive unit 222. The second transistor T2 is, for example but not limited to, one or more of a triode, a MOS transistor, and a thin film transistor. Taking the MOS transistor as an example, the second transistor T2 includes a second control electrode C2, a third transfer electrode S3, and a fourth transfer electrode S4, wherein the second control electrode C2 is the gate of the MOS transistor, and the third transfer electrode S3 is the MOS transistor. The drain of the fourth transfer electrode S4 is the source of the MOS transistor. The second control electrode C2 is connected to the second input terminal In2 for receiving an output control signal; the third transmission electrode S3 is connected to the buffer circuit for receiving an electrical signal output by the buffer circuit; and the fourth transmission electrode S4 is The first output terminal Out1 is connected for outputting an electrical signal buffered by the buffer circuit.

Further, a buffer circuit is connected between the photosensitive unit 222 and the second transistor T2 for buffering the electrical signal converted by the photosensitive unit 222, and outputs a buffered electrical signal when the second transistor T2 is turned on. In this embodiment, the buffer circuit includes a third transistor T3, such as but not limited to any one or several of a triode, a MOS transistor, and a thin film transistor. Taking the MOS transistor as an example, the third transistor T3 includes a third control electrode C3, a fifth transmission electrode S5, and a sixth transmission electrode S6, wherein the third control electrode C3 is the gate of the MOS transistor, and the fifth transmission electrode S5 is the MOS. The drain of the tube, the sixth transfer electrode S6 is the source of the MOS tube. The third control electrode C3 is connected to the negative electrode of the photodiode D1 for receiving an electrical signal generated when the photodiode D1 performs photo sensing; the fifth transmission electrode S5 is for receiving a voltage signal Vcc; and the sixth transmission electrode S6 is second. The third transfer electrode S3 of the transistor T2 is connected for outputting a buffered electrical signal when the second transistor T2 is turned on.

In the third transistor T3, the voltage Vs of the sixth transfer electrode S6 changes according to the voltage Vg of the third control electrode C3, that is, the sixth transfer electrode S6 is not affected regardless of the circuit load connected to the sixth transfer electrode S6. Voltage. Moreover, due to the characteristics of the third transistor T3, the voltage Vs is always lower than the voltage Vg by a threshold voltage which is the threshold voltage of the third transistor T3. Therefore, the buffer circuit functions as a buffer isolation to isolate the electrical signal generated when the photosensitive unit 222 performs light sensing, thereby preventing other circuit loads from affecting the photosensitive signal generated by the photosensitive unit 222, thereby ensuring accurate execution of the photosensitive pixel 22. The light sensing improves the sensing accuracy of the photosensitive device 20 on the target object.

Please refer to FIG. 3. FIG. 3 shows the signal timing at each node when the photosensitive pixel 22 shown in FIG. 2 performs light sensing, wherein Vg is the voltage on the negative electrode of the photodiode D1, and is also the third of the third transistor T3. The voltage on the electrode C3 is controlled; Vs is the voltage on the sixth transfer electrode S6 of the third transistor T3.

At time t1, the first scan driving signal is input through the first input terminal In1 while the second scan driving signal is input through the fourth input terminal In4. The first transistor T1 is turned on for a first predetermined time (ie, t2-t1) according to the first scan driving signal, and the reference signal Vref is applied through the first transfer electrode S1 and the second transfer electrode S2 during the first predetermined time To the negative pole of photodiode D1. Since the photodiode D1 has an equivalent capacitance inside, the reference signal Verf charges the equivalent capacitance inside the photodiode D1, so that the voltage on the cathode of the photodiode D1 gradually rises and remains after reaching the voltage value of the reference signal Vref. constant. According to the second scan driving signal, the fourth transistor T4 is turned on for a third predetermined time Δt2 (ie, t3-t1), and the reference signal Vref is applied to the first pole of the first capacitor c1 via the first transistor T1 and the fourth transistor T4. The board, thereby charging the first capacitor c1, the voltage on the first plate of the first capacitor c1 gradually rises and remains unchanged after reaching the voltage value of the reference signal Vref.

At time t2, the first scan driving signal changes from a high level to a low level, and the second scan driving signal remains at a high level. At this time, the first input terminal In1 becomes a low level signal, the first transistor T1 is turned off, and the first capacitor c1 forms a discharge circuit with the photodiode D1, that is, the first capacitor c1 discharges the photodiode D1, and the first capacitor c1 The voltage Vg on the first plate gradually decreases. If there is no light signal on the photodiode D1, the current inside the photodiode D1 is very weak, so that the voltage Vg on the first plate of the first capacitor c1 remains substantially unchanged; if there is an optical signal on the photodiode D1, the photoelectric A current signal proportional to the optical signal is generated inside the diode D1, and the stronger the optical signal, the larger the current generated by the photodiode D1, so the faster the voltage Vg on the first plate of the first capacitor c1 falls. Due to the characteristics of the third transistor, the voltage Vs on the sixth transfer electrode S6 of the third transistor T3 varies with the voltage Vg on the first plate of the first capacitor c1, and the voltage Vs is always lower than the voltage Vg by Vth, which Vth is the threshold voltage of the third transistor T3.

At time t3, the second scan driving signal changes from a high level to a low level. At this time, the fourth input terminal In4 becomes a low level signal, the fourth transistor T4 is turned off, and the first capacitor c1 cannot form a discharge loop, and the voltage Vg on the first plate of the first capacitor c1 remains unchanged. Then, the photosensitive signal generated when the photosensitive unit 222 performs light sensing is latched.

At time t4, the output control signal is input and output through the third input terminal In3, and the output control signal is a pulse signal, and the duration of the high level in the pulse signal is the second predetermined time. According to the output control signal, the second transistor T2 is turned on, at which time the voltage Vg on the first plate of the first capacitor c1 passes through the sixth transfer electrode S6 of the third transistor T3, the third transfer electrode S3 of the second transistor T2, and The fourth transfer electrode S4 is output from the first output terminal Out1. The voltage outputted by the first output terminal Out1 is gradually increased from a low level to a voltage Vs on the sixth transfer electrode S6, and then changes in accordance with a change in the voltage Vs on the sixth transfer electrode S6. Since the start of time t3, the first capacitor c1 latches the voltage Vg, and the voltage Vs on the sixth transfer electrode S6 will remain unchanged, so the voltage outputted by the first output terminal Out1 will be maintained at the amplitude of the voltage Vs.

At time t5, the output control signal changes from a high level to a low level, the third input terminal In3 becomes a low level signal, the second transistor T2 is turned off, and the voltage outputted from the first output terminal Out1 gradually decreases or remains unchanged. In order to ensure the effective output of the next signal, the output voltage of the first output terminal Out1 needs to gradually drop to a low level. Since the voltage outputted by the first output terminal Out1 reflects the electrical signal converted by the photodiode D1, by reading the voltage signal of the first output terminal Out1, the photodiode D1 can be obtained by changing the received optical signal. The signal size, which in turn generates biometric information of the target object.

In the embodiment of the present invention, the switch unit 221 is not only used to drive the photosensitive unit 222 to perform light sensing, but also controls the photosensitive unit 222 to end performing light sensing, and locks the electrical signal generated when the photosensitive unit 222 performs light sensing. Therefore, the photosensitive pixels in different rows can perform light sensing at the same time, and even all the photosensitive pixels simultaneously perform light sensing, thereby providing sufficient time and flexibility for the output control of the light sensing signal.

Further, the third predetermined time Δt2 may be a fixed value or a change value. Due to the larger the optical signal received by the photodiode D1, the faster the voltage Vg falls, and the faster the voltage Vs falls. Therefore, in order to achieve accurate and efficient acquisition of the photosensitive signal, according to the intensity of the received optical signal. Adjust the size of Δt2. Specifically, the greater the intensity of the optical signal, the shorter the third predetermined time Δt2; the smaller the intensity of the optical signal, the longer the third predetermined time Δt2 is increased.

In some embodiments, referring to FIG. 4, FIG. 4 shows a connection structure of the photosensitive pixels 22 in the photosensitive device 20 with respective scan lines, data lines, and signal reference lines, and the photosensitive pixels are the circuit structure shown in FIG. . The photosensitive device 20 further includes a scan line group, a data line group, and a signal reference line group electrically connected to the plurality of photosensitive pixels 22. The scan line group includes a first scan line group composed of a plurality of first scan lines, a second scan line group composed of a plurality of second scan lines, and a third scan line group composed of a plurality of third scan lines. The data line group includes a plurality of data lines, and the signal reference line group includes a plurality of signal reference lines. Taking the photosensitive array 201 in FIG. 1 as an example, in the photosensitive array 201, a row of photosensitive pixels in the X direction includes n photosensitive pixels 22 arranged at intervals, and a column of photosensitive pixels in the Y direction includes m photosensitive pixels 22 arranged at intervals, thereby The photosensitive array 201 includes a total of m*n photosensitive pixels 22. Correspondingly, the first scan line group includes m first scan lines, and the m first scan lines are arranged in the Y direction, for example, G11, G12, . . . G1m; and the second scan line group includes m second scan lines. And the m second scan lines are also arranged in the Y direction, for example, G21, G22, ..., G2m; the third scan line group includes m third scan lines, and the m third scan lines are also spaced along the Y direction. Arrange, for example, G31, G32, ... G3m; the signal reference line group includes m signal reference lines, and the m signal reference lines are arranged along the Y direction, for example, L1, L2, ... Lm; the data line group includes n data lines And the n data lines are arranged in the X direction, for example, Sn1, Sn2, ... Sn-1, Sn. Of course, the scan line group, the data line group, and the signal reference line group of the photosensitive device 20 may also be distributed in other regular manners or in an irregular manner. In addition, since the first scan line, the second scan line, the third scan line, the signal reference line, and the data line have conductivity, the first scan line, the second scan line, the third scan line, and the signal reference at the intersection position The wire and the data line are separated by an insulating material.

Specifically, the first scan line is connected to the first input end In1 of the photosensitive pixel 22, the second scan line is connected to the second input end In2 of the photosensitive pixel 22, and the signal reference line is connected to the third input end In3 of the photosensitive pixel 22. The third scan line is connected to the fourth input terminal In4 of the photosensitive pixel 22, and the data line is connected to the first output terminal Out1 of the photosensitive pixel 22. For convenience of wiring, the first scan line, the second scan line, the third scan line, and the signal reference line are all drawn from the X direction, and the data line is taken out from the Y direction.

In some embodiments, the photosensitive device 20 further includes a photosensitive driving circuit that drives the plurality of photosensitive pixels to perform light sensing, and the photosensitive driving circuit is configured to: drive all of the photosensitive pixels to simultaneously perform light sensing, and in the After the photosensitive pixels start performing the light sensing, controlling all the photosensitive pixels to end performing the light sensing to latch the electrical signals generated when the photosensitive pixels perform the light sensing; after all the photosensitive pixels finish performing the light sensing And sequentially controlling the latched electrical signal output corresponding to the plurality of photosensitive pixels. The photosensitive driving circuit causes all the photosensitive pixels to simultaneously perform light sensing, and latches the electrical signals generated when the photosensitive pixels perform light sensing, and then sequentially controls the latched electrical signal output corresponding to the photosensitive pixels. In this way, the control timing of the photosensitive pixels is made simple, and the light sensing time is short, thereby improving the sensing speed. In addition, all the photosensitive pixels perform light sensing at the same time, thereby avoiding the influence of the movement of the object on the light sensing, thereby resisting the image distortion ability, thereby improving the sensing precision.

Further, referring to FIG. 4, the photosensitive driving circuit includes a photosensitive driving unit 24, and the first scanning line, the second scanning line, the third scanning line, and the signal reference line are all connected to the photosensitive driving unit 24. Specifically, please refer to FIG. 5. FIG. 5 shows the structure of an embodiment of the photosensitive driving unit 24 of FIG. The photosensitive driving unit 24 includes a first driving circuit 241 that supplies a first scan driving signal, a second driving circuit 242 that provides an output control signal, a reference circuit 243 that supplies a reference signal Vref, and a third driving circuit that provides a second scan driving signal. 244. The circuits of the photosensitive driving unit 24 can be integrated into one control chip through a silicon process. Of course, the circuits of the photosensitive driving unit 24 can also be formed separately. For example, the first driving circuit 241 and the second driving circuit 242 and the third driving circuit 244 are formed on the same substrate together with the photosensitive pixels 22, and the reference circuit 243 is connected to the plurality of signal reference lines on the photosensitive device 20 through the flexible circuit board. .

In some embodiments, the reference circuit 243 is configured to provide a reference signal Vref that is selectively traversable by the first switch (eg, the first transistor T1 in the switching unit 221 shown in FIG. 2) The photosensitive unit 222 is electrically connected. When the first switch is closed, the reference signal Vref is transmitted to the corresponding photosensitive unit 222 through the closed first switch.

The first driving circuit 241 is electrically connected to the first scan line of the photosensitive device 20 for providing a first scan driving signal to the first switch of all the photosensitive pixels 22 to control the first switch to be closed, and at the first predetermined time ( For example, when t2-t1) shown in FIG. 3 arrives, the first switch is controlled to be turned off, thereby driving the photosensitive cells 222 in all of the photosensitive pixels 22 to start performing light sensing.

The third driving circuit 244 is electrically connected to the third scan line of the photosensitive device 20 for providing the second scan driving signal to the first of all the photosensitive pixels 22 while the first driving circuit 241 provides the first scanning driving signal. a three switch (eg, the fourth transistor T4 in the switching unit 221 shown in FIG. 3) to close the third switch while the first switch is closed, and to close the third switch for a third predetermined time (eg, When t3-t1) shown in FIG. 3, the third switch is controlled to be turned off, thereby controlling the photosensitive unit 222 in all the photosensitive pixels to end performing light sensing, and the electric signal generated when the photosensitive unit 222 performs light sensing is The first capacitor c1 is latched.

The second driving circuit 242 is electrically connected to the second scan line of the photosensitive device 20 for controlling the photosensitive unit 222 to finish performing light sensing, for example, when the third switch is turned off and reaches a fifth predetermined time (for example, FIG. 3 At time t4), a second switch for outputting a control signal to the plurality of photosensitive pixels (for example, the second transistor T2 in the signal output unit 223 shown in FIG. 3) is sequentially provided, and the second switch is controlled to be closed and continued. The second predetermined time is to sequentially output the latched electrical signals corresponding to the photosensitive cells 222 of the plurality of photosensitive pixels.

Further, in some embodiments, the second driving circuit 242 is configured to: after all the photosensitive pixels finish performing the light sensing, provide the output control signal to the plurality of second scan lines row by row or interlaced, The latched electrical signals corresponding to all the photosensitive pixels are output. The output control signal is supplied to the second scan line row by row or interlaced, thereby realizing the output of the entire line of the photosensitive signal, thereby improving the sensing speed.

Referring to Fig. 6, there is shown a timing when the photosensitive device shown in Fig. 4 performs light sensing, and the photosensitive device performs light sensing in such a manner that simultaneous photosensitive output signals are outputted line by line. Specifically, t ₁ time, to provide a first scan driving signal and a second scan driving signals to the photosensitive pixels of all rows to control all the photosensitive pixels perform light sensing, and time t ₂ the control end of the execution of all the photosensitive pixels of light Sensing, and latching an electrical signal generated when the photosensitive pixel performs photo sensing. time t _11, the photosensitive pixel row to provide the first output control signal, outputs an electrical signal to drive the latch photosensitive pixel corresponding to the first row 1, t ₁₂ time, to the photosensitive pixels of the second row provides an output control signal to drive photosensitive pixel row corresponding to the second electrical output latch ... and so on, t _1m time, the photosensitive pixel of the m-th row to provide an output control signal to drive the latch photosensitive pixel outputs an electrical signal corresponding to the m-th row. It can be seen that the time required for all the photosensitive pixels in the photosensitive device 20 to perform light sensing and output the photosensitive signal is t _1m -t ₁₁ . Since the photosensitive time of the photosensitive pixels is saved, the sensing speed of the photosensitive device 20 is improved.

Further, in some embodiments, the second driving circuit 242 is configured to provide the line by line from the beginning to the end in the order of the plurality of second scanning lines after all the photosensitive pixels finish performing the light sensing. Outputting a control signal to the plurality of second scan lines, controlling the output of the latched electrical signals corresponding to the plurality of photosensitive pixels; and providing the output control signals to the plurality of second scan lines line by line from the end to the end, Controlling a latched electrical signal output corresponding to the plurality of photosensitive pixels.

Referring to Fig. 7, there is shown a timing when the photosensitive device shown in Fig. 4 performs light sensing, and the photosensitive device performs light sensing by simultaneously sensitizing the output of the photosensitive signal twice. Specifically, t ₁ time, to provide a first scan driving signal and a second scan driving signals to the photosensitive pixels of all rows to control all the photosensitive pixels perform light sensing, and time t ₂ the control end of the execution of all the photosensitive pixels of light Sensing, and latching an electrical signal generated when the photosensitive pixel performs photo sensing. t ₂₁ controls the latched electrical signal output corresponding to the photosensitive pixel of the 1st line, t ₂₂ controls the latched electrical signal output corresponding to the photosensitive pixel of the 2nd row, and so on, and controls the photosensitive pixel of the mth line at time t _2m Corresponding latched electrical signal output; t ₃₁ controls the latched electrical signal output corresponding to the photosensitive pixel of the mth row, t ₃₂ controls the latched electrical signal output corresponding to the photosensitive pixel of the m-1th row, and so on, At t _3m , the latched electrical signal output corresponding to the photosensitive pixel of the 1st line is controlled. As can be seen from the foregoing, after the photosensitive signal is turned off by the third switch, the first capacitor c1 cannot form a loop, thereby realizing the latching of the photosensitive signal, but due to the characteristics of the transistor, even if the fourth transistor T4 is turned off, there is still a small amount. The charge is leaked through the fourth transistor T4. Therefore, when the output time of the photosensitive signal is different, the collected photosensitive signal will affect the consistency of the photosensitive information due to the charge leakage, especially the photosensitive signal with a large output time interval. Therefore, the embodiment of the present invention allows the photosensitive signal to be read twice by means of outputting the photosensitive signal twice, thereby balancing the readout latency of the different photosensitive pixels. The two readout photosensitive signals are accumulated to obtain the final photosensitive signal. Taking the photosensitive pixels of the first row and the second row as an example, the waiting time of the photosensitive pixels in the first row is t ₂₁ -t ₂ when the first signal is read, and the waiting time of the photosensitive pixels in the second row is t ₂₂ -t ₂ The waiting time of the photosensitive pixel in the first row is t _3m -t ₂ when the second signal is read, and the waiting time of the photosensitive pixel in the second row is t _3m-1 -t ₂ . Therefore, after the two signals are read, the total waiting time of the photosensitive pixels in the first row is t ₂₁ -t ₂ +t _3m -t ₂ , and the total waiting time of the photosensitive pixels in the second row is t ₂₂ -t ₂ +t _{3m- 1} -t ₂ . It can be seen that the total waiting time of the photosensitive pixels in the first row is equal to the total waiting time of the photosensitive pixels in the second row, that is, the total waiting time of each photosensitive pixel is equal, so the same line is read twice. The pixel's sensitization signal solves the effect of charge leakage on the sensitized signal acquisition, thereby improving the sensing accuracy.

Further, in some embodiments, the second driving circuit 242 is configured to provide an output control signal to the plurality of photosensitive pixels point by point in a distribution order of the plurality of photosensitive pixels after all the photosensitive pixels finish performing the light sensing. The latched electrical signal output corresponding to the plurality of photosensitive pixels is controlled. In the embodiment of the invention, the latched electrical signal corresponding to the photosensitive pixel is outputted point by point, so that the signal reading channel can be set one, thereby saving the cost of the photosensitive device. Moreover, since the signal reading speed is fast, the rapid reading of the signal can also avoid the influence of charge leakage on the photosensitive signal acquisition to a certain extent.

In some embodiments, referring to FIG. 4, the photosensitive driving circuit further includes a signal processing unit 25, and the data lines in the photosensitive device 20 shown in FIG. 4 are connected to the signal processing unit 25, and the signal processing unit 25 can be Integrated in a test chip by a silicon process. Of course, the signal processing unit 25 can also be integrated with the photosensitive driving unit 24 in one processing chip. Specifically, the signal processing unit 25 is configured to read an electrical signal output by the photosensitive pixel 22, and obtain predetermined biometric information of a target object contacting or approaching the photosensitive device 20 according to the read electrical signal. It can be understood that since the electrical signal generated when the photosensitive pixel 22 performs light sensing is latched, the signal reading of the signal processing unit 25 provides more time and flexibility, and also saves the sensing time. Speed up the sensing speed. In addition, in order to collect an accurate and effective electrical signal, the signal processing unit 25 may perform a plurality of readings on the latched electrical signals corresponding to the photosensitive pixels 22 for a second predetermined time.

In some embodiments, the signal processing unit 25 includes a plurality of processing channels, and optionally each processing channel is connected to a data line. However, it is also possible to change at least two data lines corresponding to each processing channel, and to select an electrical signal on one data line each time by means of time division multiplexing, and then select another data line. Electrical signals, and so on, until the electrical signals on all data lines are read. In this way, the number of processing channels can be reduced, thereby saving the cost of the photosensitive device 20.

Please refer to FIG. 8. FIG. 8 shows another circuit structure of one photosensitive pixel 22 in FIG. A photosensitive pixel 22 in the embodiment of the present invention has a first input terminal In1', a second input terminal In2', a third input terminal In3', a fourth input terminal In4 and a fifth input terminal In5, and a first output terminal. Out1' and second output Out2. The light sensing control signal includes a first scan driving signal and a second scan driving signal. The photosensitive pixel 22 includes a sensing unit and a signal output unit 223', and the sensing unit includes a switching unit 221' and a photosensitive unit 222'. The switch unit 221' receives a reference signal Vref through the third input terminal In3'. In addition, the switch unit 221' receives a first scan driving signal through the first input terminal In1' and receives through the fourth input terminal In4'. a second scan driving signal, and when receiving the first scan driving signal and the second scan driving signal, respectively transmitting the reference signal Vref to the first branch circuit 2221 and the second branch circuit 2222 of the photosensitive unit 222' to drive The photosensitive unit 222' performs light sensing. The photosensitive unit 222' is configured to receive an optical signal when performing light sensing, and convert the received optical signal into a corresponding electrical signal upon receiving the optical signal. The light sensing is terminated after the photosensitive unit 222' performs light sensing for a predetermined time, and the photosensitive signal generated by performing the light sensing is latched. While providing the light sensing control signal, the output control signal is provided, that is, the signal output unit 223' receives a constant current signal Is through the fifth input terminal In5, and receives the output control signal through the second input terminal In2', thereby making the constant The current signal Is is transmitted to the conversion circuit 2231, and the conversion circuit 2231 converts the constant current signal Is into two different currents according to the electrical signal of the first end of the first branch circuit 2221 and the electrical signal of the first end of the second branch circuit 2222. The signal is outputted from the first output terminal Out1' and the second output terminal Out2.

In some embodiments, the photosensitive unit 222' includes a first branch circuit 2221 and a second branch circuit 2222. The first branch circuit 2221 is configured to perform light sensing, that is, receive the optical signal, and convert the received optical signal into a corresponding electrical signal; the second branch circuit 2222 is configured to use the first end of the second branch circuit 2222. The electrical signal is maintained at the amplitude of the reference signal Vref. Specifically, the photosensitive unit 222' is similar in structure to the photosensitive unit 222 shown in FIG. 2. The photosensitive unit 222' includes a second capacitor c2 in addition to the structure of the photosensitive unit 222 shown in FIG. The first capacitor c1 is the first branch circuit 2221 of the photosensitive unit 222', and the second capacitor c2 is the second branch circuit 2222 of the photosensitive unit 222'.

Regarding the first branch circuit 2221, the first electrode of the photodiode D1 and the first plate of the first capacitor c1 are defined as the first end of the first branch circuit 2221, the anode of the photodiode D1 and the second plate of the first capacitor c1. It is the second end of the first branch circuit 2221. The working principle of the first branch circuit 2221 can be implemented by referring to the foregoing description. In the second branch circuit 2222, the first plate of the second capacitor c2 is used for receiving the reference signal Vref transmitted from the switch unit 221', and the second plate is for receiving a fixed electrical signal, such as the ground signal NGND. The reference signal Vref charges the second capacitor c2 such that the voltage Vn on the first plate of the second capacitor c2 gradually rises and remains unchanged after reaching the amplitude of the reference signal Vref. It should be noted that the first plate defining the second capacitor c2 is the first end of the second branch circuit 2222, and the second plate of the second capacitor c2 is the second end of the second branch circuit 2222.

Further, in some embodiments, the switching unit 221 includes a fifth transistor T5 and a sixth transistor T6, and an eighth transistor T8. The fifth transistor T5 and the sixth transistor T6 and the eighth transistor T8 are, for example but not limited to, one or more of a triode, a MOS transistor, and a thin film transistor. Taking the MOS transistor as an example, the fifth transistor T5 includes a fifth control electrode C5, a ninth transmission electrode S9, and a tenth transmission electrode S10, wherein the fifth control electrode C5 is the gate of the MOS transistor, and the ninth transmission electrode S9 is the MOS. The drain of the tube, the tenth transmission electrode S10 is the source of the MOS tube. The sixth transistor T6 includes a sixth control electrode C6, an eleventh transfer electrode S11, and a twelfth transfer electrode S12, wherein the sixth control electrode C6 is the gate of the MOS transistor, and the eleventh transfer electrode S11 is the drain of the MOS transistor. The twelfth transmission electrode S12 is the source of the MOS transistor. The eighth transistor T8 includes a fifth control electrode C8, a fifteenth transfer electrode S15 and a sixteenth transfer electrode S16, wherein the eighth control electrode C8 is the gate of the MOS transistor, and the fifteenth transfer electrode S15 is the drain of the MOS transistor. The sixteenth transmission electrode S16 is the source of the MOS transistor.

The fifth control electrode C5 and the sixth control electrode C6 are both connected to the first input terminal In1' for receiving the first scan driving signal; the ninth transmitting electrode S9 and the eleventh transmitting electrode S11 are both connected to the third input terminal In3' Connected for receiving the reference signal Vref; the tenth transfer electrode S10 is connected to the first end of the first branch circuit 2221 of the photosensitive unit 222' for transmitting the reference signal Vref to the photosensitive unit when the fifth transistor T5 is turned on The first branch circuit 2221 of the 222' is connected to the first end of the second branch circuit 2222 of the photosensitive unit 222' for transmitting the reference signal Vref to the photosensitive signal when the sixth transistor T6 is turned on. The second branch circuit 2222 of unit 222'.

The eighth control electrode C8 is connected to the fourth input terminal In4' for receiving the second scan driving signal; the fifteenth transmission electrode S15 is connected to the first plate of the first capacitor c1, and the sixteenth transmission electrode S16 and the photosensitive device The first electrode (for example, the negative electrode of the photodiode) is connected. Moreover, the first plate of the first capacitor c1 is used to connect the signal output unit 223', that is, the first plate of the first capacitor c1 is connected to the signal transmission unit 223'.

In some embodiments, the signal output unit 223' in the present embodiment includes a seventh transistor T7 and a conversion circuit 2231. The seventh transistor T7 is, for example but not limited to, one or more of a triode, a MOS transistor, and a thin film transistor. Taking the MOS transistor as an example, the seventh transistor T7 includes a seventh control electrode C7, a thirteenth transmission electrode S13, and a fourteenth transmission electrode S14, wherein the seventh control electrode C7 is the gate of the MOS transistor, and the thirteenth transmission electrode S13 The drain of the MOS transistor, the fourteenth transfer electrode S14 is the source of the MOS transistor. The seventh control electrode C7 is connected to the second input terminal In2' for receiving the output control signal; the thirteenth transmission electrode S11 is connected to the fifth input terminal In5 for receiving a constant current signal Is, and the fourteenth transmission electrode S14 It is connected to the conversion circuit 2231. The seventh transistor T7 is turned on according to the output control signal to transmit the constant current signal Is to the conversion circuit 2231.

Further, the conversion circuit 2231 includes a differential pair tube having three input terminals and two output terminals, wherein one input terminal is connected to the fourteenth transmission electrode S14 of the seventh transistor T7 for receiving the seventh transistor The constant current signal Is transmitted by T7; the other two inputs are correspondingly connected to the first end of the first branch circuit 2221 (ie, the negative pole of the photodiode D1 and the first plate of the first capacitor c1) and the second branch circuit 2222 a first end (ie, a first plate of the second capacitor c2); the two outputs are based on the electrical signal Vp of the first end of the first branch circuit 2221 and the electrical signal Vn of the first end of the second branch circuit 2222 The constant current signal Is is converted into two different current signals Ip and In, and the sum of the amplitudes of the two different current signals is equal to the amplitude of the constant current signal Is.

Specifically, the conversion circuit 2231 includes a ninth transistor T9 and a tenth transistor T10. The ninth transistor T9 and the tenth transistor T10 are, for example but not limited to, any one or several of a triode and a MOS transistor. Taking the MOS transistor as an example, the tenth transistor T10 includes a tenth control electrode C10, a nineteenth transmission electrode S19, and a twentieth transmission electrode S20, wherein the ninth control electrode C9 is the gate of the MOS transistor, and the nineteenth transmission electrode S19 is the drain of the MOS transistor, and the twentieth transfer electrode S20 is the source of the MOS transistor. The ninth transistor T9 includes a ninth control electrode C9, a seventeenth transmission electrode S17, and an eighteenth transmission electrode S18, wherein the ninth control electrode C9 is the gate of the MOS transistor, and the seventeenth transmission electrode S17 is the drain of the MOS transistor. The eighteenth transmission electrode S18 is the source of the MOS transistor.

The ninth control electrode C9 of the ninth transistor T9 is connected to the first end of the first branch circuit 2221 (for example, the first plate of the first capacitor c1); the fourteenth transmission of the seventeenth transfer electrode S17 and the seventh transistor T7 The electrode S14 is connected to receive the constant current signal Is transmitted by the seventh transistor T7; the eighteenth transmission electrode S18 is connected to the first output terminal Out1' for outputting a current signal Ip. The tenth control electrode C10 of the tenth transistor T10 is connected to the first end of the second branch circuit 2222 (for example, the first plate of the second capacitor c2); the fourteenth transmission of the nineteenth transfer electrode S19 and the seventh transistor T7 The electrode S14 is connected for receiving the constant current signal Is transmitted by the seventh transistor T7; the twentieth transmission electrode S20 is connected to the second output terminal Out2 for outputting another current signal In.

Further, the tenth transistor T10 and the ninth transistor T9 form a differential pair tube when the voltage Vp on the ninth control electrode C9 of the ninth transistor T9 and the voltage Vn on the tenth control electrode C10 of the tenth transistor T10 are equal. The differential pair tube is in an equilibrium state, and the eighteenth transfer electrode S18 of the ninth transistor T9 and the twentieth transfer electrode S20 of the tenth transistor T10 output current signals of equal amplitude. When there is a voltage difference between the voltage Vp on the ninth control electrode C9 of the ninth transistor T9 and the voltage Vn on the tenth control electrode C10 of the tenth transistor T10, the differential pair tube outputs two differential electrical signals having different amplitudes. By inputting differential electrical signals of different magnitudes to the two input terminals of the differential amplifier, a corresponding amplified electrical signal can be obtained.

Please refer to FIG. 9. FIG. 9 shows the signal timing when the photosensitive pixel 22 of FIG. 8 performs light sensing, wherein Vp is the voltage on the first plate of the first capacitor c1, that is, the voltage on the negative terminal of the photodiode D1. Vn is the voltage on the first plate of the second capacitor c2; In is the current signal outputted by the first output terminal Out1', and Ip is the current signal outputted by the second output terminal Out2.

At time t1, the first scan driving signal is input through the first input terminal In1' while the second scan driving signal is input through the fourth input terminal In4'. The fifth transistor T5 and the sixth transistor T6 are turned on according to the high level signal, and the eighth transistor T8 is turned on according to the high level signal.

When the fifth transistor T5 is turned on, the reference signal Vref is transmitted to the negative electrode of the photodiode D1 via the ninth transfer electrode S9 and the tenth transfer electrode S10. Since the photodiode D1 has an equivalent capacitance inside, the reference signal Verf charges the equivalent capacitance inside the photodiode D1, so that the voltage on the cathode of the photodiode D1 gradually rises and remains after reaching the voltage value of the reference signal Vref. constant. Meanwhile, when the eighth transistor T6 is turned on, the reference signal Vref passes through the fifth transistor T5, and then is transmitted to the first plate of the first capacitor c1 via the eighth transistor T8, thereby charging the first capacitor c1. The voltage Vp on the first plate of a capacitor c1 gradually rises and remains unchanged after reaching the voltage value of the reference signal Vref.

When the sixth transistor T6 is turned on, the reference signal Vref is transmitted to the first plate of the second capacitor c2 via the eleventh transfer electrode S11 and the twelfth transfer electrode S12, thereby charging the second capacitor c2, and second The voltage Vn on the first plate of the capacitor c2 gradually rises and remains unchanged after reaching the voltage value of the reference signal Vref.

At time t2, the first scan driving signal is switched from a high level to a low level, and the second scan driving signal is still a high level signal. Therefore, the first input terminal In1' becomes a low level signal, and the fourth input terminal In4' is still a high level signal, and the fifth transistor T5 and the second transistor T2 are both turned off, and the eighth transistor T8 is still turned on. The first capacitor c1 forms a discharge loop with the photodiode D1, that is, the first capacitor c1 discharges the photodiode D1, and the voltage Vp on the first plate of the first capacitor c1 gradually decreases. If there is no light signal on the photodiode D1, the current inside the photodiode D1 is very weak, so that the voltage Vp on the first plate of the first capacitor c1 remains substantially unchanged; if there is light signal on the photodiode D1, the photoelectric A current signal proportional to the optical signal is generated inside the diode D1, and the stronger the optical signal, the larger the current generated by the photodiode D1, so the faster the voltage Vp on the first plate of the first capacitor c1 falls. When the sixth transistor T6 is turned off, the second capacitor c2 cannot form a discharge loop, and the voltage Vn on the first plate of the second capacitor c2 will remain unchanged, that is, the reference signal Vref is maintained unchanged.

At time t3, the second scan driving signal is converted from a high level signal to a low level signal. Therefore, the fourth input terminal In4' becomes a low level signal, the eighth transistor T8 is turned off, and the first capacitor c1 cannot form a discharge loop, and the voltage Vp on the first plate of the first capacitor c1 remains unchanged. Then, the photosensitive signal obtained by the photosensitive unit 222' is latched.

At time t4, an output control signal is input through the second input terminal In2', and the output control signal is a high level signal. Since the output control signal is a high level signal, the seventh transistor T7 is turned on, and the conversion circuit 2231 converts the constant current signal into a two-electric signal and outputs it. If the amplitudes of the voltage Vp and the voltage Vn coincide, the differential pair tube of the conversion circuit 2231 is in an equilibrium state, and the electrical signal output by the first output terminal Out1' is equal to the electrical signal outputted by the second output terminal Out2. If the amplitudes of the voltage Vp and the voltage Vn do not match, that is, there is a certain difference, the differential pair of the conversion circuit 2231 outputs two current signals having different amplitudes. And the sum of the amplitudes of the two current signals is equal to the amplitude of the constant current signal. After the light sensing unit 222' performs light sensing, the electrical signal Vp at the first end of the first branch circuit 2221 is gradually decreased, and the electrical signal Vn at the first end of the second branch circuit 2222 is maintained at Vref, the electrical signal Vn is There is a voltage difference between the electrical signals Vp, and the more the electrical signal Vp falls, the larger the voltage difference. Therefore, as shown in FIG. 9, since the eighth transistor T8 is turned off from the time t3, the voltage Vp is maintained constant by the first capacitor c1, and the voltage Vn is also maintained by the second capacitor c2. Therefore, when the seventh transistor T7 is turned on at time t4, the amplitude of the current signal Ip outputted by the first output terminal Out1' corresponds to the amplitude of the electrical signal Vp, and the amplitude and power of the current signal In output by the second output terminal Out2 The amplitude of the signal Vn corresponds. Further, since the voltage of the electric signal Vp drops, the amplitude of the current signal In rises compared to the current amplitude at the equilibrium state, and the magnitude of the current signal Ip decreases compared to the current amplitude at the equilibrium state. The two differential signals are input to the differential amplifier and the electrical signal output is doubled compared to the one electrical signal, thereby achieving signal amplification.

At time t5, the output control signal is changed from the high level signal to the low level signal, so the second input terminal In2' becomes a low level signal, and the seventh transistor T7 is turned off, then the first output terminal Out1' and the second output terminal Out2 stops outputting the electrical signal, which becomes a low level signal. During the period between time t5 and time t4, the corresponding current signal is read from the first output terminal Out1' and the second output terminal Out2, and the photosensitive unit 222 can be obtained according to the two current signals. 'Perform a current signal generated by light sensing to obtain biometric information of the target object.

Further, in the third predetermined time Δt2 between the time t3 and the time t2, the photosensitive unit 222' performs light sensing, and latches an electric signal generated when performing light sensing at time t3. Moreover, the third predetermined time Δt2 may be a fixed value or a change value. Since the optical signal received by the photodiode D1 is larger, the rate of decrease of the voltage Vp is faster. Therefore, in order to achieve accurate and efficient acquisition of the photosensitive signal, the magnitude of Δt2 is adjusted according to the intensity of the received optical signal. Specifically, the larger the optical signal intensity is, the shorter Δt2 is; the smaller the optical signal intensity is, the longer Δt2 is.

Further, since the photosensitive signal generated when the photosensitive unit 222' performs light sensing is latched, the interval between the time t4 and the time t3 can be flexibly set, and all the photosensitive cells 222' can simultaneously perform light sensing, so that The control timing is simple, and the entire sensitized readout time is short, which is advantageous for shortening the sensing time and improving the user experience. Optionally, in order to prevent charge leakage of the latch signal during the readout waiting process, the latched signal is controlled when each of the photosensitive cells 222' ends performing light sensing and reaches a fifth predetermined time (eg, t4-t3). Output.

In the embodiment of the present invention, the switch unit 221' is not only used to drive the photosensitive unit 222' to perform light sensing, but also controls the photosensitive unit 222' to finish performing light sensing, and the photosensitive unit 222' performs light sensing. The electrical signals are latched, so that the photosensitive pixels in different rows can simultaneously perform light sensing, and even all of the photosensitive pixels simultaneously perform light sensing, thereby providing sufficient time and flexibility for the output control of the light sensing signal. In addition, the photosensitive pixel 22 passes through the structure of the differential pair tube, so that the current signal generated by the photosensitive unit 222' performing the light sensing is outputted as two differential signals, thereby realizing the amplification of the electrical signal, and adding the two differentials. The signals are outputs of the current signal relative to the voltage signal, which improves the anti-interference ability of the signal, thereby improving the sensing accuracy of the photosensitive device 20.

In some embodiments, referring to FIG. 10, the difference from the photosensitive pixel 22 shown in FIG. 8 is that, in the photosensitive pixel 22 in the embodiment of the present invention, the tenth transmission electrode S10 of the fifth transistor T5 and the first capacitance c1 The first plate is connected. After the fifth transistor T5 and the sixth transistor T6 are turned off, due to the characteristics of the transistor, even if the transistor is in an off state, the transistor may have a certain leakage phenomenon, so a part of the charge on the second capacitor c2 will be from the sixth transistor T6. Leakage, which will cause leakage imbalance. In this regard, the embodiment of the present invention is connected to the first plate of the first capacitor c1 through the first transistor T1, so that after the fifth transistor T5 and the sixth transistor T6 are turned off, even if there is leakage phenomenon, the first capacitor c1 and the second The leakage of the capacitor c2 is uniform, that is, the problem of leakage imbalance is solved, and the sensing accuracy of the photosensitive device 20 is improved.

Further, referring to FIG. 11 , the photosensitive device 20 further includes a scan line group, a data line group, and a signal reference line group electrically connected to the plurality of photosensitive pixels 22 . The scan line group includes a first scan line group composed of a plurality of first scan lines, a second scan line group composed of a plurality of second scan lines, and a third scan line group composed of a plurality of third scan lines. The data line group includes a plurality of data lines, and the signal reference line group includes a plurality of signal reference lines. Taking the photosensitive array 201 in FIG. 1 as an example, in the photosensitive array 201, a row of photosensitive pixels in the X direction includes n photosensitive pixels 22 arranged at intervals, and a column of photosensitive pixels in the Y direction includes m photosensitive pixels 22 arranged at intervals, thereby The photosensitive array 201 includes a total of m*n photosensitive pixels 22. Correspondingly, the first scan line group includes m first scan lines, and the m first scan lines are arranged in the Y direction, for example, G11, G12, . . . G1m; and the second scan line group includes m second scan lines. And the m second scan lines are also arranged in the Y direction, for example, G21, G22, ..., G2m; the third scan line group includes m third scan lines, and the m third scan lines are also spaced along the Y direction. Arrange, for example, G31, G32, ... G3m; the signal reference line group includes m signal reference lines, and the m signal reference lines are arranged along the Y direction, for example, L1, L2, ... Lm; the data line group includes n data lines And the n data lines are arranged in the X direction, for example, Sn1, Sn2, ... Sn-1, Sn. Of course, the scan line group, the data line group, and the signal reference line group of the photosensitive device 20 may also be distributed in other regular manners or in an irregular manner. In addition, since the first scan line, the second scan line, the third scan line, the signal reference line, and the data line have conductivity, the first scan line, the second scan line, the third scan line, and the signal reference at the intersection position The wire and the data line are separated by an insulating material.

Specifically, the first scan line is connected to the first input end In1 ′ of the photosensitive pixel 22 , the second scan line is connected to the second input end In 2 ′ of the photosensitive pixel 22 , and the signal reference line and the third input end In 3 of the photosensitive pixel 22 . 'Connected, the third scan line is connected to the fourth input terminal In4' of the photosensitive pixel 22, the first data line is connected to the first output end Out1' of the photosensitive pixel 22, and the second data line is connected to the second output end of the photosensitive pixel 22. The Out2' is connected, and the third data line is connected to the wth input terminal In5 of the photosensitive pixel 22. The first scan line, the second scan line, the third scan line, and the signal reference line are all drawn from the X direction, and the first data line, the second data line, and the third data line are extracted from the Y direction. .

In some embodiments, the photosensitive device 20 further includes a photosensitive driving circuit, the photosensitive driving circuit is further configured to: drive all photosensitive pixels in the photosensitive device to simultaneously perform light sensing, and start performing light sensing on the photosensitive pixels. After that, all the photosensitive pixels are controlled to end the light sensing; after all the photosensitive pixels finish performing the light sensing, the latched electrical signal outputs corresponding to the plurality of photosensitive pixels are sequentially controlled.

Further, referring to FIG. 11 , the photosensitive driving circuit includes a photosensitive driving unit 24 , and the first scanning line, the second scanning line, the third scanning line, and the signal reference line are all connected to the photosensitive driving unit 24 . Specifically, referring to FIG. 12, the photosensitive driving unit 24 includes a first driving circuit 241' that provides a first scan driving signal, a second driving circuit 242' that provides an output control signal, and a signal reference circuit 243' that provides a reference signal Vref. And a third driving circuit 244' that provides a second scan driving signal. The circuits of the photosensitive driving unit 24 can be integrated into one control chip through a silicon process. Of course, the circuits of the photosensitive driving unit 24 can also be formed separately. For example, the first driving circuit 241' and the second driving circuit 242', the third driving circuit 244' are formed on the same substrate together with the photosensitive pixels 22, and the signal reference circuit 243' passes through the flexible circuit board and the photosensitive device 20 Strip signal reference lines are connected.

In some embodiments, the reference circuit 243' is used to provide a reference signal Vref that passes through a fourth switch of the photosensitive pixel 22 (eg, the fifth transistor T5 in the switching unit 221' shown in FIG. 8) The first branch circuit 2221 of the photosensitive unit 222' is selectively electrically connected. When the fourth switch is closed, the reference signal Vref is transmitted to the first branch circuit 2222 of the photosensitive unit 222' through the closed fourth switch. Meanwhile, the reference circuit 243' is further selectively connected to the second branch of the photosensitive unit 222' through a fifth switch of the photosensitive pixel 22 (for example, the sixth transistor T6 in the switching unit 221' shown in FIG. 8). Circuit 2222 is electrically connected. When the fifth switch is closed, the reference signal Vref is transmitted to the second branch circuit 2222 of the photosensitive unit 222' through the closed fifth switch.

The first driving circuit 241 ′ is electrically connected to the first scan line of the photosensitive device 20 for providing a first scan driving signal to the fourth switch and the fifth switch of all the photosensitive pixels 22 , and the third driving circuit 244 ′ and the photosensitive device The third scan line of the device 20 is electrically connected for providing a second scan drive signal to the seventh switch of all the photosensitive pixels 22 while the first drive circuit 241' provides the first scan drive signal (for example, FIG. 8 The eighth transistor T8) of the switch unit 221' is shown to control the fourth switch, the fifth switch and the seventh switch to be closed, and when the first predetermined time arrives, the fourth switch and the fifth switch are controlled to be turned off, thereby driving The photosensitive unit 222' starts to perform light sensing; when the third predetermined time arrives, the seventh switch is controlled to be turned off, thereby controlling the photosensitive unit 222' to end performing light sensing, and the photosensitive unit 222' is generated by the first capacitor c1. The light sensing signal is latched.

The second driving circuit 242 ′ is electrically connected to the second scanning line of the photosensitive device 20 for controlling the photosensitive unit 222 to end performing the light sensing, for example, when the seven switches are turned off and reach the fifth predetermined time (as shown in FIG. 7 ). At time t4 shown), an output control signal is sequentially provided to the sixth switch of the plurality of photosensitive pixels 22 to control the sixth switch (for example, the seventh transistor T7 of the signal output unit 223' shown in FIG. 6) to be closed, and When the second predetermined time arrives, the sixth switch is controlled to be turned off. During the second predetermined time, the conversion circuit 2231 converts the constant current signal into two different current signals according to the electrical signal generated when the photosensitive unit 222' performs light sensing, and outputs the same.

Further, the second driving circuit 242 ′ controls the plurality of photosensitive pixels 22 in the same manner as the second driving circuit 242 controls the plurality of photosensitive pixels 22 , that is, provides an output control signal to the plurality of rows or rows. The sixth switch of the photosensitive pixels 22 is controlled to output the latch signals of the plurality of photosensitive pixels 22 row by row or interlaced. And according to the distribution order of the photosensitive pixels 22, the output control signals are provided row by row to the plurality of photosensitive pixels 22, and the output control signals are provided to the plurality of photosensitive pixels 22 from the end to the end to lock the same photosensitive pixels 22. The signal is read twice. And outputting a control signal to the sixth switch of the plurality of photosensitive pixels 22 point by point according to the distribution order of the photosensitive pixels to control the latching signals of the plurality of photosensitive pixels 22 to be output point by point. For specific control processes and benefits, please refer to the previous embodiments.

In some embodiments, please continue to refer to FIG. 11 , the photosensitive driving circuit further includes a signal processing unit 25 , and the data lines in the photosensitive device 20 shown in FIG. 11 are connected to the signal processing unit 25 , and the signal processing unit 25 can be Integrated in a test chip by a silicon process. Of course, the signal processing unit 25 can also be integrated with the photosensitive driving unit 24 in a processing chip. Specifically, the signal processing unit 25 is configured to read a current signal output by the photosensitive pixel 22 from the first output terminal Out1' and the second output terminal Out2, and obtain contact or proximity to the photosensitive device 20 according to the read electrical signal. Predetermined biometric information of the target object. It can be understood that since the electrical signal generated when the photosensitive pixel 22 performs light sensing is latched, the signal reading of the signal processing unit 25 provides more time and flexibility, and also saves the sensing time. Speed up the sensing speed. In addition, in order to collect an accurate and effective electrical signal, the signal processing unit 25 may perform a plurality of readings on the latched electrical signals corresponding to the photosensitive pixels 22 for a second predetermined time.

In some embodiments, please refer to FIG. 13, which shows the structure of a photosensitive device according to another embodiment of the present invention. The photosensitive device 20 further includes a photosensitive panel 200. The photosensitive panel 200 further includes a substrate 26 on which a plurality of photosensitive pixels 22 are disposed. Optionally, the photosensitive pixels 22 are distributed in an array. The photosensitive driving circuit is configured to drive the plurality of photosensitive pixels to perform light sensing, and control an electrical signal output generated when the photosensitive pixel performs light sensing. When the photosensitive pixel 22 performs light sensing, it is used to receive the above-mentioned optical signal, and convert the received optical signal into a corresponding electrical signal, so that the photosensitive regions of the plurality of photosensitive pixels 22 define the sensing region 203, and the sense The area other than the measurement area 203 is the non-sensing area 202. In order to facilitate the wiring, the non-sensing area 202 is used to set a driving circuit required for the photosensitive pixel 22 to perform light sensing, such as the above-described photosensitive driving circuit. Alternatively, the non-sensing area 202 is used to set a line bonding area to which the power supply connector is connected. For example, taking the photosensitive device 20 shown in FIG. 11 as an example, the first driving circuit 241' and the second driving circuit 242', the third driving circuit 244', and the reference circuit 243' are both formed on the substrate 26. Alternatively, the first driving circuit 241 ′, the second driving circuit 242 ′, the third driving circuit 244 ′, and the reference circuit 243 ′ are electrically connected to the photosensitive pixels 22 through electrical connectors (eg, flexible circuit boards).

In some embodiments, the signal processing unit 25 described above can be selectively formed on the substrate 26 depending on the type of the substrate 26, or can be selectively electrically connected to the photosensitive pixel 22, for example, by an electrical connector (eg, a flexible circuit board). For example, when the substrate 26 is a silicon substrate, the signal processing unit 25 may be selectively formed on the substrate 26, or may be electrically connected to the photosensitive pixel 22, for example, by a flexible circuit board; when the substrate 26 is an insulating substrate The signal processing unit 25 then needs to be electrically connected to the photosensitive pixels 22, for example, via a flexible circuit board.

In some embodiments, the photosensitive device 20 is a photosensitive chip for sensing biometric information of a target object that contacts or approaches the photosensitive device 20. Optionally, the photosensitive device 20 is a fingerprint sensing chip for sensing a fingerprint image of a user's finger.

Further, based on the above-mentioned photosensitive device, an embodiment of the present invention further provides a light sensing method of the photosensitive device. Referring to FIG. 14, FIG. 14 shows specific steps of a photo sensing method of a photosensitive device according to an embodiment of the present invention. The photo sensing method of the photoreceptor includes the following steps:

S11, providing a first scan driving signal and a second scan driving signal to all the photosensitive pixels, so that all the photosensitive pixels start to perform light sensing when the first predetermined time arrives, and end the execution of the light sense when the third predetermined time arrives. Measuring, latching an electrical signal generated when performing light sensing on the photosensitive pixel;

S12, after all the photosensitive pixels finish performing the light sensing, sequentially providing an output control signal to the plurality of photosensitive pixels to control the latched electrical signal output corresponding to the plurality of photosensitive pixels.

The light sensing method is applied to collect predetermined biometric information of an object on the photosensitive device, and determines whether the identity of the object is legal according to the collected predetermined biometric information, such as fingerprint recognition. Specifically, based on the photosensitive device 20 shown in FIG. 4 and the photosensitive pixel structure shown in FIG. 2, step S11 is specifically: providing a first scan driving signal to the first switch of all the photosensitive pixels 22 (for example, FIG. 2 The first transistor T1) in the illustrated switching unit 221 simultaneously supplies a second scan driving signal to a third switch of all the photosensitive pixels 22 (for example, the fourth transistor T4 in the switching unit 221 shown in FIG. 3) to Controlling that the first switch and the third switch of all the photosensitive pixels 22 are closed, and when the first predetermined time arrives, controlling the first switch to be turned off, the photosensitive unit 222 starts performing light sensing; at the third predetermined When the time arrives, the third switch is controlled to be turned off, and the photosensitive unit 222 ends performing light sensing.

Step S12 is specifically: after the third switch of the switch unit 221 is turned off, sequentially providing the output control signal to the second switch (for example, the second transistor T2 in the signal output unit 223 shown in FIG. 3) The second switch that controls the signal output unit 223 is closed, and the electrical signal generated when the photosensitive unit 222 of the photosensitive pixel 22 performs light sensing is output.

Based on the photosensitive device 20 shown in FIG. 11 and the photosensitive pixel structure shown in FIG. 8, step S11 is specifically to provide the first scan driving signal to the fourth switch of all the photosensitive pixels 22 (for example, as shown in FIG. The fifth transistor T5) and the fifth switch (for example, the sixth transistor T6 in the switching unit 221' shown in FIG. 8) of the switching unit 221' simultaneously provide a second scan driving signal to the first of all the photosensitive pixels 22. a seven switch (such as the eighth transistor T8 of the switching unit 221' shown in FIG. 8) to control the fourth switch and the fifth switch and the seventh switch of all the photosensitive pixels 22 to be closed, and arrive at the first predetermined time Controlling that the fourth switch and the fifth switch are turned off, the photosensitive unit 222' starts to perform light sensing; when the third predetermined time arrives, the seventh switch is controlled to be turned off, and the photosensitive unit 222' ends. Light sensing is performed, and the first capacitor c1 latches an electrical signal generated when the photosensitive unit 222' performs light sensing.

Step S12 is specifically: after the seventh switch of the switch unit 221' is turned off, sequentially providing the output control signal to the sixth switch (for example, the seventh transistor T7 of the signal output unit 223' shown in FIG. And closing the sixth switch of the signal output unit 223' to cause the conversion circuit to receive a constant electrical signal, and converting the constant electrical signal into two according to the electrical signal latched by the photosensitive unit 222' Different electrical signals and outputs.

Further, in some embodiments, step S12 includes: after all the photosensitive pixels finish performing the light sensing, providing the output control signal to the plurality of photosensitive pixels row by row or interlaced until all the photosensitive pixels correspond to The latched electrical signals are all output.

Continuing to refer to FIG. 6, the photosensitive device performs light sensing by simultaneously sensing the output of the photosensitive signal line by line. Specifically, t ₁ time, to provide a first scan driving signal and a second scan driving signals to the photosensitive pixels of all rows to control all the photosensitive pixels perform light sensing, and time t ₂ the control end of the execution of all the photosensitive pixels of light Sensing, and latching an electrical signal generated when the photosensitive pixel performs photo sensing. time t _11, the photosensitive pixel row to provide the first output control signal, outputs an electrical signal to drive the latch photosensitive pixel corresponding to the first row 1, t ₁₂ time, to the photosensitive pixels of the second row provides an output control signal to drive photosensitive pixel row corresponding to the second electrical output latch ... and so on, t _1m time, the photosensitive pixel of the m-th row to provide an output control signal to drive the latch photosensitive pixel outputs an electrical signal corresponding to the m-th row. It can be seen that the time required for all the photosensitive pixels in the photosensitive device 20 to perform light sensing and output the photosensitive signal is t _1m -t ₁₁ . Since the photosensitive time of the photosensitive pixels is saved, the sensing speed of the photosensitive device 20 is improved.

Further, in some embodiments, step S12 includes: after all the photosensitive pixels finish performing the light sensing, providing the output control signal to the station line by line from the beginning to the end according to the distribution order of the plurality of photosensitive pixels The plurality of photosensitive pixels are further provided, and the output control signal is provided to the plurality of photosensitive pixels from the end to the beginning, so that the electrical signals outputted twice are accumulated to obtain a final electrical signal.

Continuing to refer to FIG. 7, the photosensitive device performs photo sensing by simultaneously sensitizing the output of the photosensitive signal twice. Specifically, t ₁ time, to provide a first scan driving signal and a second scan driving signals to the photosensitive pixels of all rows to control all the photosensitive pixels perform light sensing, and time t ₂ the control end of the execution of all the photosensitive pixels of light Sensing, and latching an electrical signal generated when the photosensitive pixel performs photo sensing. t ₂₁ controls the latched electrical signal output corresponding to the photosensitive pixel of the 1st line, t ₂₂ controls the latched electrical signal output corresponding to the photosensitive pixel of the 2nd row, and so on, and controls the photosensitive pixel of the mth line at time t _2m Latched electrical signal output; t ₃₁ controls the latched electrical signal output corresponding to the photosensitive pixel of the mth line, t ₃₂ controls the electrical signal output of the photosensitive pixel latch of the m-1th line, and so on, t _3m The electric signal output of the photosensitive pixel latch of the 1st line is controlled at all times. As can be seen from the foregoing, after the photosensitive signal is turned off by the third switch, the first capacitor c1 cannot form a loop, thereby realizing the latching of the photosensitive signal, but due to the characteristics of the transistor, even if the fourth transistor T4 is turned off, there is still a small amount. The charge is leaked through the fourth transistor T4. Therefore, when the output time of the photosensitive signal is different, the collected photosensitive signal will affect the consistency of the photosensitive information due to the charge leakage, especially the photosensitive signal with a large output time interval. Therefore, the embodiment of the present invention allows the photosensitive signal to be read twice by means of outputting the photosensitive signal twice, thereby balancing the readout latency of the different photosensitive pixels. The two readout photosensitive signals are accumulated to obtain the final photosensitive signal. Taking the photosensitive pixels of the first row and the second row as an example, the waiting time of the photosensitive pixels in the first row is t ₂₁ -t ₂ when the first signal is read, and the waiting time of the photosensitive pixels in the second row is t ₂₂ -t ₂ The waiting time of the photosensitive pixel in the first row is t _3m -t ₂ when the second signal is read, and the waiting time of the photosensitive pixel in the second row is t _3m-1 -t ₂ . Therefore, after the two signals are read, the total waiting time of the photosensitive pixels in the first row is t ₂₁ -t ₂ +t _3m -t ₂ , and the total waiting time of the photosensitive pixels in the second row is t ₂₂ -t ₂ +t _{3m- 1} -t ₂ . It can be seen that the total waiting time of the photosensitive pixels in the first row is equal to the total waiting time of the photosensitive pixels in the second row, that is, the total waiting time of each row of photosensitive pixels is equal, so that the same row of photosensitive pixels is read twice. The sensitization signal solves the effect of charge leakage on the sensitization signal acquisition, thereby improving the sensing accuracy.

Further, in some embodiments, step S12 includes: after all the photosensitive pixels finish performing light sensing, providing the output control signal to the plurality of points point by point according to a distribution order of the plurality of photosensitive pixels Photosensitive pixels.

In the embodiment of the invention, the electrical signal latched by the photosensitive pixel is outputted point by point, so that the signal reading channel can be set one, thereby saving the cost of the photosensitive device. Moreover, since the signal reading speed is fast, the rapid reading of the signal can also avoid the influence of charge leakage on the photosensitive signal acquisition to a certain extent.

15 and FIG. 16, FIG. 15 shows a structure of an electronic device according to an embodiment of the present invention, and FIG. 16 shows a cross-sectional structure of an embodiment of the electronic device shown in FIG. Fig. 16 shows only a partial structure of an electronic device. The electronic device includes the photosensitive device of any of the above embodiments, which is used for image display of an electronic device and for sensing biometric information of a target object contacting or approaching the electronic device.

Electronic devices such as, but not limited to, suitable types of electronic products such as consumer electronics, home electronics, vehicle-mounted electronic products, and financial terminal products. Among them, consumer electronic products such as mobile phones, tablets, notebook computers, desktop monitors, computer integrated machines. Home-based electronic products such as smart door locks, TVs, refrigerators, wearable devices, etc. Vehicle-mounted electronic products such as car navigation systems, car DVDs, etc. Financial terminal products such as ATM machines, terminals for self-service business, etc. The electronic device shown in FIG. 15 is exemplified by a mobile terminal of the mobile phone type. However, the bio-sensing module can also be applied to other suitable electronic products, and is not limited to mobile terminals.

Specifically, a display device (not shown) is disposed on the front surface of the mobile terminal 3, and the display device includes a display panel 300. The protective cover 400 is disposed above the display panel 300. Optionally, the screen of the display panel 300 is relatively high, for example, 80% or more. The screen ratio refers to the ratio of the display area 305 of the display panel 300 to the front area of the mobile terminal 3. In the photosensitive device 20 (see FIGS. 4 and 8 ), the photosensitive panel 200 is a panel structure that is adapted to the display panel 300 and is disposed below the display panel 300 . If the display panel 300 is in the form of a flexible curved surface, the photosensitive panel 200 is also in the form of a flexible curved surface. Therefore, the photosensitive panel 200 not only has a planar structure but also a curved surface structure. In this way, the lamination of the photosensitive panel 200 and the display panel 300 is facilitated.

Since the photosensitive panel 200 is located below the display panel 300, the display panel 300 has a light-transmitting region through which an optical signal reflected from the target object passes, so that the photosensitive panel 200 can receive the optical signal passing through the display panel 300 and receive The incoming optical signal is converted into an electrical signal, and predetermined biometric information of the target object contacting or approaching the electronic device is acquired according to the converted electrical signal.

In the embodiment of the present invention, in addition to the effect of the photosensitive device 20 described in the above embodiments, the electronic device utilizes the optical signal emitted by the display panel 300 to realize the biometric information sensing of the target object, without additionally providing a light source. Not only does the cost of the electronic device be saved, but biometric information sensing of the target object in the display area 305 of the touch or touch display panel 300 is also achieved. In addition, the photosensitive device 20 can be independently fabricated, and then assembled with an electronic device, thereby accelerating the preparation of the electronic device.

When the mobile terminal 3 is in a bright screen state and is in the biometric information sensing mode, the display panel 300 emits an optical signal. When an object contacts or approaches the display area, the photosensitive device 20 receives the optical signal reflected by the object, converts the received optical signal into a corresponding electrical signal, and acquires predetermined biometric information of the object according to the electrical signal. For example, fingerprint image information. Thereby, the photosensitive device 20 can realize sensing of a target object that contacts or approaches an arbitrary position of the display area.

In some embodiments, the display panel 300 is, for example but not limited to, an OLED display device, as long as a display device capable of realizing a display effect and having a light-transmitting region through which an optical signal passes is within the scope of the present invention. In addition, the display panel 300 can be a bottom emission structure, a top emission structure, and a double-sided light transmission structure. Moreover, the display screen can be a rigid screen of a rigid material or a flexible screen of a flexible material.

In some embodiments, the photosensitive panel 200 is configured to perform biometric information sensing of a target object at any position within the display area of the display panel 300. For example, specifically, for example, referring to FIG. 15, FIG. 16, and FIG. 17, the display panel 300 has a display area 305 and a non-display area 306 defined by the light-emitting areas of all the display pixels 32 of the display panel 300. The area other than the display area 305 is a non-display area 306 for setting a circuit such as a display driving circuit for driving the display pixels 32 or a line bonding area for connecting the flexible circuit boards. The photosensitive panel 200 has a sensing area 203 and a non-sensing area 204 defined by the sensing areas of all the photosensitive pixels 22 of the photosensitive panel 200, and the area other than the sensing area 203 is the non-sensing area 204. The non-sensing area 204 is for setting a circuit such as the photosensitive driving unit 24 that drives the photosensitive pixel 22 to perform light sensing or a line bonding area for connecting the flexible circuit board. The shape of the sensing region 203 is consistent with the shape of the display region 305, and the size of the sensing region 203 is greater than or equal to the size of the display region 305, such that the photosensitive panel 200 can be placed at any position adjacent to or adjacent to the display region 305 of the display panel 300. Sensing of predetermined biometric information of the target object. Further, the area of the photosensitive panel 200 is less than or equal to the area of the display panel 300, and the shape of the photosensitive panel 200 is consistent with the shape of the display panel 300, so that the assembly of the photosensitive panel 200 and the display panel 300 is facilitated. However, in some embodiments, the area of the photosensitive panel 200 may also be larger than the area of the display panel 300.

In some embodiments, the sensing area 203 of the photosensitive panel 200 may also be smaller than the display area 305 of the display panel 300 to achieve the sense of predetermined biometric information of the target object of the display area 300 displaying the local area of the area 305. Measurement.

Further, the display device is further configured to perform touch sensing, and after the display device detects the touch or proximity of the target object, the control display panel emits light corresponding to the position of the touch region.

However, in some embodiments, please refer to FIG. 18. FIG. 18 shows a cross-sectional structure of another embodiment of the electronic device shown in FIG. 15 along line II, and FIG. 18 only shows the electronic Part of the structure of the device. The photosensitive module of the embodiment of the present invention is applied to a mobile terminal 3, and a display panel 300 is disposed on the front surface of the mobile terminal, and a protective cover 400 is disposed above the display panel 300. The screen of the display panel 300 is relatively high, for example, 80% or more. The screen ratio refers to the ratio of the actual display area 305 of the display panel 300 to the front area of the mobile terminal. A bio-sensing area for the target object touch is provided at a middle-lower position of the actual display area 305 of the display panel 300 to perform biometric information sensing of the target object. For example, if the target object is a finger, the bio-sensing area is Fingerprint identification area for fingerprint recognition. Correspondingly, a photosensitive device 20 is disposed at a position corresponding to the fingerprint recognition area below the display panel 300, and the photosensitive device 20 is configured to acquire a fingerprint image of the finger when the finger is placed on the fingerprint recognition area. It can be understood that the middle and lower positions of the display panel 300 are for the convenience of the finger to touch the position of the display panel 300 when the user holds the mobile terminal. Of course, it can also be placed at other locations that are convenient for finger touch.

In some embodiments, the electronic device further includes a touch sensor (not shown) by which the touch area of the target object on the protective cover 400 can be determined. The touch sensor adopts capacitive touch sensing technology, and of course, other methods, such as resistive touch sensing, pressure sensitive touch sensing, and the like. The touch sensor is configured to determine a touch area of the target object when a target object contacts the protective cover 400 to drive a display pixel corresponding to the touch area to light and the photosensitive pixel to perform light sensing.

In some embodiments, the touch sensor is either integrated with the protective cover 400, or integrated with the photosensitive panel 200, or integrated with the display panel 300. The integrated touch sensor not only realizes the touch detection of the target object, but also reduces the thickness of the electronic device, which is beneficial to the development of the electronic device in the direction of thinning and thinning.

In the description of the present specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiment", "example", "specific example", or "some examples", etc. The specific features, structures, materials or characteristics described in the embodiments or examples are included in at least one embodiment or example of the invention. In the present specification, the schematic representation of the above terms does not necessarily mean the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples.

Although the embodiments of the present invention have been shown and described, it is understood that the above-described embodiments are illustrative and are not to be construed as limiting the scope of the invention. The embodiments are subject to changes, modifications, substitutions and variations.

Claims

A light sensing method of a photosensitive device, the photosensitive device comprising a plurality of photosensitive pixels, wherein the light sensing method comprises the following steps:

Providing a first scan driving signal and a second scan driving signal to all of the photosensitive pixels such that all of the photosensitive pixels start performing light sensing when the first predetermined time arrives, and ending performing light sensing when the third predetermined time arrives, Latching an electrical signal generated when performing light sensing on the photosensitive pixel;

After all the photosensitive pixels finish performing the light sensing, an output control signal is sequentially provided to the plurality of photosensitive pixels to control the latched electrical signal output corresponding to the plurality of photosensitive pixels.
The light sensing method of the photosensitive device according to claim 1, wherein the plurality of photosensitive pixels are arranged in an array; and after all the photosensitive pixels finish performing light sensing, the output control signals are sequentially provided. The step of giving the plurality of photosensitive pixels specifically includes:

After all the photosensitive pixels finish performing the light sensing, the output control signals are provided to the plurality of photosensitive pixels row by row or interlaced until the latched electrical signals corresponding to all the photosensitive pixels are output.
The light sensing method of the photosensitive device according to claim 1, wherein the plurality of photosensitive pixels are arranged in an array; and after all the photosensitive pixels finish performing light sensing, the output control signals are sequentially provided. The step of giving the plurality of photosensitive pixels specifically includes:

After all the photosensitive pixels finish performing the light sensing, the output control signals are provided row by row to the plurality of photosensitive pixels from beginning to end according to the distribution order of the plurality of photosensitive pixels, and then provided from the end to the top by line. The output control signal is sent to the plurality of photosensitive pixels to accumulate the electrical signals that are output twice to obtain a final electrical signal.
The light sensing method of the photosensitive device according to claim 1, wherein the step of sequentially providing the output control signal to the plurality of photosensitive pixels after the photo sensing is completed is completed. include:

After all the photosensitive pixels finish performing the light sensing, the output control signals are provided to the plurality of photosensitive pixels point by point according to the distribution order of the plurality of photosensitive pixels.
The photosensitive sensing method of the photosensitive device according to claim 1, wherein the photosensitive pixel comprises a photosensitive unit and a switching unit electrically connected to the photosensitive unit, and the photosensitive unit comprises at least one photosensitive device and a first capacitor, the switch unit includes a first switch and a third switch; the step of providing the first scan driving signal and the second scan driving signal to all the photosensitive pixels further includes:

Providing the first scan driving signal to the first switch of all the photosensitive pixels while providing a second scan driving signal to the third switch of all the photosensitive pixels to control the first switch and the third switch of all the photosensitive pixels Closing, and when the first predetermined time arrives, controlling the first switch to be turned off, the photosensitive unit starts performing light sensing; and when the third predetermined time arrives, controlling the third switch to be turned off, the light sensing The unit ends performing light sensing.
The photosensitive sensing method of the photosensitive device according to claim 5, wherein the photosensitive pixel further comprises a signal output unit electrically connected to the photosensitive unit, the signal output unit comprising a second switch; After all the photosensitive pixels finish performing the light sensing, the step of sequentially providing an output control signal to the plurality of photosensitive pixels further includes:

After the third switch of the switch unit is turned off, the output control signal is sequentially supplied to the second switch to control the second switch of the signal output unit to be closed, and the photosensitive unit in the photosensitive pixel is output to perform light. The electrical signal generated during sensing.
The photosensitive sensing method of the photosensitive device according to claim 1, wherein the photosensitive pixel comprises a photosensitive unit and a switching unit electrically connected to the photosensitive unit; the photosensitive unit comprises at least one photosensitive device, a capacitor and a second capacitor, the switch unit includes a fourth switch, a fifth switch, and a seventh switch; the step of providing the first scan driving signal and the second scan driving signal to all the photosensitive pixels further includes:

Providing the first scan driving signal to the fourth switch and the fifth switch of all the photosensitive pixels while providing a second scan driving signal to the seventh switch of all the photosensitive pixels to control the fourth switch of all the photosensitive pixels And the fifth switch and the seventh switch are closed, and when the first predetermined time arrives, the fourth switch and the fifth switch are controlled to be turned off, the photosensitive unit starts to perform light sensing; when the third predetermined time arrives, The seventh switch is controlled to be turned off, the photosensitive unit ends performing light sensing, and the first capacitance latches an electrical signal generated when the photosensitive unit performs light sensing.
The light sensing method of the photosensitive device according to claim 7, wherein the photosensitive pixel further comprises a signal output unit electrically connected to the photosensitive unit, the signal output unit comprising a sixth switch and a conversion circuit After the photo sensing is completed, the step of sequentially controlling the output of the electrical signals generated when the plurality of photosensitive pixels perform photo sensing further comprises:

After the seventh switch of the switch unit is turned off, the output control signal is sequentially provided to the sixth switch to control the sixth switch of the signal output unit to be closed, so that the conversion circuit receives a constant electrical signal. And converting the constant electrical signal into two different electrical signals according to an electrical signal latched by the photosensitive unit, and outputting.
The light sensing method of a photosensitive device according to claim 5 or 7, wherein the third predetermined time is dynamically adjusted in accordance with the intensity of the received optical signal.
The light sensing method of the photosensitive device according to claim 6, wherein the greater the intensity of the received optical signal, the shorter the third predetermined time; the smaller the intensity of the received optical signal, The third predetermined time is longer.
A light sensing method of a photosensitive device according to claim 8, wherein said constant electric signal is a constant current signal.
The light sensing method of the photosensitive device according to claim 1, wherein the light sensing method further comprises:

Predetermining biometric information of an object contacting or approaching the photosensitive device is acquired based on the electrical signals generated when the plurality of photosensitive pixels are read to perform light sensing.