CN112183254A

CN112183254A - Photosensitive drive circuit, photosensitive device and electronic equipment

Info

Publication number: CN112183254A
Application number: CN202010970065.4A
Authority: CN
Inventors: 李问杰
Original assignee: Shenzhen Sunwave Technology Co Ltd
Current assignee: Liuzhou Zibo Technology Co.,Ltd.
Priority date: 2017-12-30
Filing date: 2017-12-30
Publication date: 2021-01-05
Also published as: CN108229387A; CN108229387B

Abstract

The invention discloses a photosensitive driving circuit, a photosensitive device and electronic equipment, wherein the photosensitive driving circuit is used for sequentially driving a plurality of photosensitive pixels to perform photosensitive sensing; and after the photosensitive pixel starts to perform light sensing, controlling the photosensitive pixel to perform electric signal output generated during light sensing. The photosensitive device comprises a plurality of photosensitive pixels and the photosensitive driving circuit, and the electronic equipment comprises the photosensitive device.

Description

Photosensitive drive circuit, photosensitive device and electronic equipment

Technical Field

The invention relates to a photosensitive driving circuit for sensing biological characteristic information, a photosensitive device and electronic equipment.

Background

At present, fingerprint identification has gradually become a standard component of electronic products such as mobile terminals. Since optical fingerprint recognition has a stronger penetration ability 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 the mobile terminal still needs to be improved.

Disclosure of Invention

The embodiment of the invention aims to solve at least one technical problem in the prior art. Therefore, the embodiments of the present invention need to provide a photosensitive driving circuit, a photosensitive device, and an electronic apparatus.

The photosensitive driving circuit is used for sequentially driving the plurality of photosensitive pixels to perform light sensing; and after the photosensitive pixel starts to perform light sensing, controlling the photosensitive pixel to perform electric signal output generated during light sensing.

The light sensing method of the embodiment of the invention not only can control the light sensing time of the light sensing pixel, but also realizes the timely and effective output of the electric signal generated by the light sensing unit by outputting the control signal, thereby improving the sensing precision. In addition, the output of the photosensitive signals of the photosensitive pixels is controlled by the output control signals, so that the photosensitive pixels are isolated from the signals of the output end, the photosensitive signals of the photosensitive pixels are prevented from being influenced by other circuit loads, accurate photosensitive signals are obtained, and the sensing precision is further improved.

In some embodiments, the plurality of photosensitive pixels are distributed on a substrate in an array, and the substrate is further provided with a plurality of first scan lines electrically connected with the plurality of photosensitive pixels respectively; the photosensitive driving circuit includes:

and the first driving circuit is correspondingly and electrically connected with the first scanning line and is used for providing a first scanning driving signal to the photosensitive pixels line by line or in an interlaced manner so as to drive the photosensitive pixels to execute light sensing line by line or in an interlaced manner.

In some embodiments, the first drive circuit is further configured to:

after the first scanning driving signal is provided to the photosensitive pixel of the current row, the output control signal is provided to the photosensitive pixel of the current row so as to drive the photosensitive pixel of the current row to perform light sensing, and the electric signal generated in the light sensing execution process is controlled to be output, the first scanning driving signal is provided to the photosensitive pixel of the next row.

When the photosensitive device in the embodiment of the invention performs light sensing, the photosensitive pixels in the current row perform light sensing, and after the photosensitive signals generated during the light sensing are read, the photosensitive pixels in the next row perform light sensing, so that the reading of the photosensitive signals of each row of photosensitive pixels is not interfered with each other, and accurate photosensitive signals can be obtained. In addition, since the time required for the photosensitive device to perform the primary light sensing is long, it can be used as a test mode.

In some embodiments, the first drive circuit is further configured to:

providing the first scanning driving signal to the photosensitive pixels of the next line when the first scanning driving signal is provided to the photosensitive pixels of the current line and a preset time is reached; the predetermined time is at least one clock cycle.

According to the embodiment of the invention, the photosensitive device is in a rolling photosensitive mode, so that the time for the photosensitive device to perform primary photosensitive is short, and the time for all photosensitive pixels to wait for reading photosensitive signals is consistent, namely, the influence of charge leakage on photosensitive signal acquisition is solved, and the sensing precision is improved.

In some embodiments, a plurality of second scan lines electrically connected to the plurality of photosensitive pixels are further disposed on the substrate; the photosensitive driving circuit further comprises: and the second driving circuit is correspondingly and electrically connected with the second scanning line and is used for providing the output control signal to each photosensitive pixel when each photosensitive pixel starts to perform light sensing and reaches a fourth preset time so as to control the output of an electric signal generated when the photosensitive pixel performs the light sensing.

In some embodiments, the second drive circuit is further configured to: and controlling the light sensing pixels to output the electric signals generated when the light sensing pixels perform light sensing and last for a second preset time.

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

The embodiment of the invention adjusts the reading time of the electric signals generated by the photosensitive pixels in time according to the intensity of the optical signals, ensures the accurate reading of the electric signals and improves the sensing precision.

In some embodiments, the substrate is further provided with a data line electrically connected to the plurality of photosensitive pixels; the photosensitive driving circuit further comprises a signal processing unit, wherein the signal processing unit is electrically connected with the data lines and is used for reading the electric signals output by the photosensitive pixels and obtaining preset biological characteristic information of a target object contacting or approaching the photosensitive pixels according to the read electric signals.

In some embodiments, the photosensitive driving circuit is formed on the substrate or electrically connected to the plurality of photosensitive pixels through an electrical connector; or, a part of circuits of the photosensitive driving circuit is formed on the substrate, and the other part of circuits is electrically connected with the plurality of photosensitive pixels through a connecting piece.

The photosensitive device provided by the embodiment of the invention comprises a plurality of photosensitive pixels and the photosensitive driving circuit of any one of the above embodiments, wherein the photosensitive driving circuit is used for driving the plurality of photosensitive pixels to perform photosensitive sensing, and controlling the photosensitive pixels to output electric signals generated when the photosensitive pixels perform photosensitive sensing after the photosensitive pixels start to perform photosensitive sensing.

In some embodiments, the photosensitive device is a fingerprint sensing device for collecting fingerprint information of a finger.

In some embodiments, the photosensitive device is a biosensing chip for acquiring predetermined biometric information of a target object in proximity to or in contact with the photosensitive device.

An electronic device according to an embodiment of the present invention includes the light sensing device according to any one of the above embodiments.

Additional aspects and advantages of embodiments of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of embodiments of the invention.

Drawings

The above and/or additional aspects and advantages of embodiments of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic diagram illustrating an array distribution of photosensitive pixels in a photosensitive device according to an embodiment of the present invention;

FIG. 2 is a schematic circuit diagram of one embodiment of the light-sensing pixel of FIG. 1;

FIG. 3 is a timing diagram of signals at nodes of the photosensitive pixel of FIG. 2 when performing light sensing;

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

FIG. 5 is a block diagram of an embodiment of the photosensitive driving unit shown in FIG. 4;

FIG. 6 is a timing diagram of signals of the embodiment of the photosensitive device shown in FIG. 4 performing photo sensing;

FIG. 7 is a timing diagram illustrating signals of another embodiment of the light sensing apparatus shown in FIG. 4;

FIG. 8 is a schematic circuit diagram of another embodiment of the light-sensing pixel of FIG. 1;

FIG. 9 is a timing diagram illustrating signals at nodes of the photosensitive pixel of FIG. 8 when performing light sensing;

FIG. 10 is a diagram illustrating a connection structure between a photosensitive pixel and a scan line, a data line and a signal reference line in the photosensitive device according to an embodiment of the present invention, wherein the photosensitive pixel is the photosensitive pixel structure shown in FIG. 8;

FIG. 11 is a block diagram of an embodiment of the photosensitive driving unit shown in FIG. 10;

FIG. 12 is a schematic view of a structure of a photosensitive panel in the photosensitive device according to an embodiment of the invention;

fig. 13 is a flowchart illustrating a light sensing method of a light sensing device according to an embodiment of the invention;

FIG. 14 is a schematic structural diagram of an electronic device to which a photosensitive device according to an embodiment of the present invention is applied;

fig. 15 is a schematic sectional view of the electronic apparatus shown in fig. 14 taken along the line I-I, and fig. 15 shows a partial structure of the electronic apparatus;

FIG. 16 is a schematic diagram illustrating a position of a display region of a display panel and a sensing region of a photosensitive panel according to an embodiment of the present invention;

FIG. 17 is a schematic structural diagram of an electronic device to which a photosensitive device according to an embodiment of the present invention is applied;

fig. 18 is a schematic sectional view of the electronic apparatus shown in fig. 17 taken along the line II-II, and fig. 18 shows a partial structure of the electronic apparatus.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

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

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

The following disclosure provides many different embodiments or examples for implementing different features of the invention. To simplify the disclosure of the present invention, the components and settings of a specific example are described below. Of course, they are merely examples and are not intended to limit the present invention. Furthermore, the present invention may repeat reference numerals and/or reference letters in the various examples, which have been repeated for purposes of simplicity and clarity and do not in themselves dictate a relationship between the various embodiments and/or configurations discussed. In addition, the present invention provides examples of various specific processes and materials, but one of ordinary skill in the art may recognize applications of other processes and/or uses of other materials.

Further, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other structures, components, and so forth. In other instances, well-known structures or operations are not shown or described in detail to avoid obscuring the invention.

The embodiment of the invention provides a photosensitive device arranged in electronic equipment, and particularly provides a photosensitive device arranged below a display screen of the electronic equipment. Such as, but not limited to, OLED display panels and the like, have display devices that emit light signals. When the electronic equipment works, the display screen sends out optical signals to execute corresponding image display. At this time, if a target object contacts or touches the electronic device, the optical signal emitted by the display screen is reflected after reaching the target object, the reflected optical signal passes through the display screen and is received by the photosensitive device, and the photosensitive device converts the received optical signal into an electrical signal corresponding to the optical signal, so as to form the predetermined biological characteristic information of the target object according to the electrical signal generated by the photosensitive device.

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

In some embodiments, the electronic device may also be provided with a light source for biometric information sensing. When the electronic equipment executes the biological characteristic information sensing, the light source emits corresponding light signals, such as infrared light, so that the sensing of information of heart rate, blood oxygen concentration, veins and the like of a target object is realized.

Examples of the electronic devices include, but are not limited to, consumer electronics, home electronics, vehicle-mounted electronics, financial terminal products, and other suitable types of electronic products. The consumer electronic products include mobile phones, tablet computers, notebook computers, desktop displays, all-in-one computers, and the like. The household electronic products are intelligent door locks, televisions, refrigerators, wearable equipment and the like. The vehicle-mounted electronic products are vehicle-mounted navigators, vehicle-mounted DVDs and the like. The financial terminal products are ATM machines, terminals for self-service business handling and the like.

Referring to fig. 1, fig. 1 shows an array distribution structure of photosensitive pixels in a photosensitive device, in which the photosensitive device 20 includes a plurality of photosensitive pixels 22, and the plurality of photosensitive pixels 22 are arranged in rows and columns 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, each row of photosensitive pixels being spaced apart along the X-direction, and each column of photosensitive pixels being spaced apart along the Y-direction. When the photosensitive device 20 performs image sensing, each row of photosensitive pixels 22 may be driven line by line in the X direction to perform light sensing, and then an electrical signal generated by each photosensitive pixel 22 performing light sensing may be read in the Y direction. Of course, the photosensitive pixels 22 forming the photosensitive array 201 are not limited to the vertical relationship shown in fig. 1, and may be distributed in other regular or irregular manners.

In some embodiments, each light-sensitive pixel 22 includes a sensing unit and a signal output unit. The sensing unit is used for receiving a light sensing control signal and executing light sensing when receiving the light sensing control signal. When light sensing is performed, the sensing unit receives a light signal and converts the received light signal into a corresponding light sensing signal, namely an electric signal; the signal output unit is used for receiving an output control signal and outputting a photosensitive signal generated when the sensing unit executes photosensitive sensing when receiving the output control signal.

In particular, referring to fig. 2, fig. 2 illustrates a circuit configuration of one of the light-sensitive pixels 22 of fig. 1. Accordingly, the light-sensing pixel 22 may also be referred to as a light-sensing circuit. A light-sensitive pixel 22 of the present embodiment has a first input terminal In1, a second input terminal In2, a third input terminal In3, and a first output terminal Out 1. The light sensing control signal includes a first scan driving signal. The light-sensing pixel 22 includes a sensing unit including a switching unit 221 and a light-sensing unit 222, and a signal output unit 223, and the light-sensing 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, and the switch unit 221 further receives a first scan driving signal through the first input terminal In1 and transmits the reference signal Vref to the photosensitive unit 222 when receiving the first scan driving signal, so as to drive the photosensitive unit 222 to operate. The light sensing unit 222 is configured to receive a light signal and convert the received light signal into a corresponding electrical signal when receiving the light 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 light sensing unit 222 from the first output terminal Out1 according to the output control signal.

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

In some embodiments, the light sensing unit 222 includes a light sensing device, which includes a first electrode and a second electrode, the first electrode is used for receiving the reference signal Vref transmitted by the switch unit 221, and the second electrode is used 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 electric signal to both electrodes of the photosensitive device. Such as, but not limited to, photodiode D1, and alternatively, the light sensing device may also be a photo-resistor, a photo-transistor, a thin film transistor, or the like. It should be noted that the number of the photosensitive devices may also be 2, 3, and so on. Taking the photodiode D1 as an example, the photodiode D1 includes an anode and a cathode, wherein the anode receives a predetermined electrical signal, such as the ground signal NGND; the negative electrode is used as a first electrode of the light sensing device and is used for receiving the reference signal Vref transmitted by the switch unit 221. It should be noted that, when the reference signal Vref is applied to the two ends of the photodiode D1 corresponding to the predetermined signal, a reverse voltage is formed across the photodiode D1, so as to drive the photodiode D1 to perform light sensing.

When the switch unit 221 is closed, the reference signal Vref is transmitted to the cathode of the photodiode D1 through the closed switch unit 221, and since the photodiode D1 has an equivalent capacitance therein, the reference signal Verf charges the equivalent capacitance inside the photodiode D1, so that the voltage Vg on the cathode of the photodiode D1 gradually rises and reaches the voltage value of the reference signal Vref and remains unchanged when the first predetermined time is reached. At this time, the voltage difference across the photodiode D1 reaches the reverse voltage driving the photodiode to operate, i.e., the photodiode D1 is in an operating state. Since the first scan driving signal is converted from the high level signal to the low level signal when the first predetermined time is reached, the switch unit 221 is turned off according to the low level signal, and a discharge loop is formed inside the photodiode D1. At this time, when an optical signal is irradiated to the photodiode D1, the reverse current of the photodiode D1 increases rapidly, and the voltage Vg at the negative electrode node of the photodiode D1 changes accordingly, i.e., decreases gradually. Further, since the larger the intensity of the optical signal, the larger the reverse current generated by the photodiode D1, the faster the voltage Vg on the negative node of the photodiode D1 drops.

Further, the light sensing unit 222 further includes a first capacitor c 1. The first capacitor c1 is used for forming a discharge circuit with the photosensitive device to obtain a corresponding photosensitive signal when performing photosensitive sensing. Specifically, as shown in fig. 2, the first capacitor c1 is disposed in parallel with the photo sensing device, i.e., 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 connected to a predetermined electrical signal, e.g., the ground signal NGND. When the reference signal Vref is transmitted to the cathode of the photodiode D1, the first capacitor c1 is also charged, and when the switch unit 221 is turned off, the first capacitor c1 and the photodiode D1 form a discharge loop, and the voltage of the first plate of the first capacitor c1 (i.e., the voltage Vg) also gradually decreases. By arranging the first capacitor c1, the capacitance capacity of the photosensitive unit 222 is increased, so that the voltage drop speed on the cathode of the photodiode D1 is reduced, an effective photosensitive signal can be acquired, and the sensing precision of the photosensitive device 20 on a 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 arranged in parallel, and the capacitance change of the first capacitor c1 is realized by controlling whether the plurality of capacitors are connected or not. Since the first capacitor c1 is set as a variable capacitor, the capacity of the first capacitor c1 is adjusted to adapt to the change of the received optical signal, so as to obtain an accurate and effective photosensitive signal. Specifically, the capacitance of the first capacitor c1 increases as the intensity of the received optical signal increases, and the capacitance of the first capacitor c1 decreases as the intensity of the received optical signal decreases.

In some embodiments, the switch unit 221 includes a first transistor T1, and the first transistor T1 is, for example, but not limited to, any one or more of a triode, a MOS transistor, and a thin film transistor. Taking a 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, the first transfer electrode S1 is a drain of the MOS transistor, and the second transfer electrode S2 is a source of the MOS transistor. The first control electrode C1 is connected to the first input terminal In1 and is configured to receive a first scan driving signal; the first transfer electrode S1 is connected to the third input terminal In3 for receiving a reference signal Vref; the second transfer electrode S2 is connected to the cathode of the photodiode D1 in the light sensing unit 222. When a 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 applied to the cathode of the photodiode D1 and the first plate of the first capacitor c1 through the first transfer electrode S1 and the second transfer electrode S2; the first transistor T1 is turned on and turned off after a first predetermined time, and the first capacitor c1 and the photodiode D1 form a discharge loop to start performing the photo sensing.

In some embodiments, the signal output unit 223 includes a second transistor T2 and a buffer circuit. The buffer circuit is used for buffering the electrical signal generated by the light sensing unit 222. The second transistor T2 is, for example, but not limited to, any one or more of a triode, a MOS transistor, and a thin film transistor. Taking a 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 a gate of the MOS transistor, the third transfer electrode S3 is a drain of the MOS transistor, and the fourth transfer electrode S4 is a 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 with the buffer circuit and used for receiving the electric signal output by the buffer circuit; the fourth transmission electrode S4 is connected to the first output terminal Out1, and is used for outputting the electric signal buffered by the buffer circuit.

Further, a buffer circuit is connected between the light sensing unit 222 and the second transistor T2 for buffering the electrical signal converted by the light sensing unit 222 and outputting the buffered electrical signal when the second transistor T2 is turned on. In this embodiment, the buffer circuit includes a third transistor T3, and the third transistor T3 is, for example, but not limited to, any one or more of a triode, a MOS transistor, and a thin film transistor. Taking a MOS transistor as an example, the third transistor T3 includes a third control electrode C3, a fifth transfer electrode S5 and a sixth transfer electrode S6, wherein the third control electrode C3 is a gate of the MOS transistor, the fifth transfer electrode S5 is a drain of the MOS transistor, and the sixth transfer electrode S6 is a source of the MOS transistor. The third control electrode C3 is connected to the cathode of the photodiode D1 and is used for receiving an electrical signal generated when the photodiode D1 performs light sensing; the fifth transmitting electrode S5 is for receiving a voltage signal Vcc; the sixth transfer electrode S6 is connected to the third transfer electrode S3 of the second transistor T2, 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 with the change of the voltage Vg of the third control electrode C3, i.e., the voltage of the sixth transfer electrode S6 is not affected regardless of the change of the circuit load connected to the sixth transfer electrode S6. Also, due to the transistor characteristics, the voltage Vs is always lower than the voltage Vg by a threshold voltage of the third transistor T3. Therefore, the buffer circuit plays a role of buffer isolation, and isolates the electrical signal generated when the photosensitive unit 222 performs light sensing, so as to prevent other circuit loads from affecting the photosensitive signal generated by the photosensitive unit 222, thereby ensuring that the photosensitive pixels 22 accurately perform light sensing, and improving the sensing precision of the photosensitive device 20 on the target object.

Referring to fig. 3, fig. 3 shows the signal timing at each node when the photosensitive pixel 22 shown in fig. 2 performs light sensing, where Vg is the voltage at the cathode of the photodiode D1 and is also the voltage at the third control electrode C3 of the third transistor T3; vs is a voltage on the sixth transfer electrode S6 of the third transistor T3.

At time T1, a first scan driving signal is input through the first input terminal In1, such that the first transistor T1 is turned on and turned off after a first predetermined time (i.e., T2-T1) In which the reference signal Vref is transmitted to the cathode of the photodiode D1 and the first plate of the first capacitor c1 via the first transmission electrode S1 and the second transmission electrode S2. Since the photodiode D1 has an equivalent capacitance therein, the reference signal Verf charges the equivalent capacitance inside the photodiode D1, so that the voltage Vg at the cathode of the photodiode D1 gradually rises and remains unchanged after reaching the voltage value of the reference signal Vref. In addition, since the first capacitor c1 is connected in parallel with the photodiode D1, the reference signal Vref charges the first capacitor c1, so that the voltage on the first plate 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 high to low, that is, the first input terminal In1 changes to low, the first transistor T1 is turned off, and a discharge loop is formed between the equivalent capacitor and the first capacitor c1 and the photodiode D1. When the photodiode D1 is illuminated by the optical signal, a current signal proportional to the optical signal is generated inside the photodiode D1, and thus the voltage Vg at the cathode of the photodiode D1 gradually decreases. Also, the stronger the optical signal, the faster the voltage Vg decreases. In addition, due to the voltage following characteristic of the third transistor T3, the voltage Vs on the sixth transfer electrode S6 of the third transistor T3 varies with the voltage Vg on the cathode electrode of the photodiode D1, and the voltage Vs is always lower than the voltage Vg by Vth, which is the threshold voltage of the third transistor T3. It should be noted that the first predetermined time is to ensure that the photodiode in the light sensing unit 22 and the first capacitor c1 are charged to the reference signal Vref.

At time T3, that is, after the light sensing unit 222 starts to perform the light sensing and reaches the fourth predetermined time (i.e., T3-T2), the output control signal is input through the second input terminal In2, the second transistor T2 is turned on according to the high level signal, and the voltage Vs on the sixth transmission electrode S6 of the third transistor T3 is output from the first output terminal Out1 through the third transmission electrode S3 and the fourth transmission electrode S4 of the second transistor T2. The voltage output from the first output terminal Out1 gradually rises from the low level to the voltage Vs on the sixth transmission electrode S6, and then changes with the change of the voltage Vs on the sixth transmission electrode S6. It should be noted that the fourth predetermined time is at least one clock cycle, and the fourth predetermined time cannot be too long, and certainly cannot be too short, so as to ensure that the light sensing signal generated when the light sensing unit 222 performs light sensing can be effectively and timely output.

At time T4, the output control signal changes from a high level signal to a low level signal, that is, the second input terminal In2 changes to a low level signal, the second transistor T2 is turned off, and the voltage output by the first output terminal Out1 gradually drops or remains unchanged. In order to ensure the effective output of the next signal, the output voltage of the first output terminal Out1 is gradually decreased to a low level. During the period between the time T4 and the time T3, that is, during the second predetermined time Δ T1, the voltage Vs on the sixth transfer electrode S6 of the third transistor T3 (i.e., the voltage Vg on the negative electrode of the photodiode D1) is output from the first output terminal Out1, so that the magnitude of the light sensing signal generated by the photodiode D1 due to the light signal received by reading the voltage signal of the first output terminal Out1 can be obtained, and the biometric information of the target object can be generated.

Further, the second predetermined time Δ t1 may be a fixed value or a variable value. Since the larger the light signal received by the photodiode D1, the faster the falling speed of the voltage Vg and thus the voltage Vs, the magnitude of Δ t1 is adjusted according to the intensity of the received light signal in order to achieve accurate and efficient acquisition of the light sensing signal. Specifically, the greater the light signal intensity, the shorter the second predetermined time Δ t 1; the smaller the light signal intensity, the longer the second predetermined time Δ t 1.

In some embodiments, referring to fig. 4, fig. 4 illustrates a connection structure of the photosensitive pixels 22 in the photosensitive device 20 with the respective scan lines, data lines, and signal reference lines, and the photosensitive pixels are in the circuit structure illustrated in fig. 2. 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 scanning line group comprises a first scanning line group consisting of a plurality of first scanning lines and a second scanning line group consisting of a plurality of second scanning lines, the data line group comprises a plurality of data lines, and the signal reference line group comprises a plurality of signal reference lines. Taking the photo-sensing array 201 in fig. 1 as an example, in the photo-sensing array 201, a row of photo-sensing pixels in the X direction includes n photo-sensing pixels 22 arranged at intervals, and a column of photo-sensing pixels in the Y direction includes m photo-sensing pixels 22 arranged at intervals, so that the photo-sensing array 201 includes m × n photo-sensing pixels 22 in total. Correspondingly, the first scan line group includes m first scan lines, and the m first scan lines are arranged at intervals along the Y direction, such as G11, G12, … G1 m; the second scan line group further includes m second scan lines, and the m second scan lines are also arranged at intervals along the Y direction, such as G21, G22, … G2 m; the signal reference line group comprises m signal reference lines, and the m signal reference lines are arranged at intervals along the Y direction, such as L1, L2, … Lm; the data line group comprises n data lines which are arranged at intervals along the X direction, such as S1, S2, … Sn-1 and Sn. Of course, the scan line group, the data line group and the signal reference line group of the light sensing device 20 may be distributed in other regular or irregular manners. In addition, since the first scan line, the second scan line, the signal reference line, and the data line have conductivity, the first scan line, the second scan line, the signal reference line, and the data line at the crossing position are isolated from each other by an insulating material.

Specifically, m first scan lines are correspondingly connected to the first input terminals In1 of the plurality of photosensitive pixels 22, m second scan lines are correspondingly connected to the second input terminals In2 of the plurality of photosensitive pixels 22, m signal reference lines are correspondingly connected to the third input terminals In3 of the plurality of photosensitive pixels 22, and n data lines are correspondingly connected to the first output terminals Out1 of the plurality of photosensitive pixels 22. For convenience of wiring, the first scanning line, the second scanning line and the signal reference line are all led out from the X direction, and the data line is led out from the Y direction.

In some embodiments, the photosensitive device 20 further includes a photosensitive driving circuit, which is configured to sequentially drive the plurality of photosensitive pixels 22 to perform photosensitive sensing; after the photosensitive pixel 22 starts to perform the light sensing, the photosensitive pixel 22 is controlled to perform the output of the electrical signal generated when the light sensing is performed.

Further, with reference to fig. 4, the photo-sensing driving circuit includes a photo-sensing driving unit 24, and the first scan line, the second scan line, and the signal reference line of the photo-sensing device 20 are all connected to the photo-sensing driving unit 24. Referring to fig. 5, fig. 5 shows a structure of an embodiment of the sensing driving unit 24 in fig. 4. The photosensitive driving unit 24 includes a first driving circuit 241 which supplies a first scan driving signal, a second driving circuit 242 which supplies an output control signal, and a reference circuit 243 which supplies a reference signal Vref. The circuits of the photosensitive driving unit 24 can be integrated in one control chip through silicon process, but the circuits of the photosensitive driving unit 24 can also be separately formed in different control chips. For example, the first and

second driving circuits

241 and 242 are formed on the same substrate together with the light-sensing pixels 22, and the reference circuit 243 is connected to a plurality of signal reference lines on the light-sensing device 20 through a connection member (e.g., a flexible circuit board).

In some embodiments, the reference circuit 243 is used for providing the reference signal Vref, and the reference circuit 243 is selectively electrically connected to the light-sensing unit 222 through a first switch (e.g., the first transistor T1 in the switch unit 221 shown in fig. 2) of the light-sensing pixel 22. When the first switch is closed, the reference signal Vref is transmitted to the corresponding light sensing 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, and configured to provide a first scan driving signal to the first switch in the photosensitive pixel 22 line by line or in an interlaced manner, so as to control the first switch to be turned on, and when a first predetermined time is reached, control the first switch to be turned off, so as to drive the photosensitive unit 222 to start performing light sensing.

The second driving circuit 242 is electrically connected to the second scan line of the photosensitive device 20, and is configured to provide an output control signal to a second switch (e.g., the second transistor T2 in the signal output unit 223 shown in fig. 2) in the photosensitive pixel 22 when each photosensitive pixel starts to perform light sensing and reaches a fourth predetermined time (e.g., the first switch is opened and reaches the fourth predetermined time (e.g., T3-T2 shown in fig. 3), and control the second switch to be closed, so that the photosensitive unit 222 performs the output of an electrical signal generated in the light sensing.

Further, in some embodiments, the first driving circuit 241 is further configured to: and after the first scanning driving signal is provided for the photosensitive pixel of the current line and the output control signal is provided for the photosensitive pixel of the current line so as to drive the photosensitive pixel of the current line to perform light sensing and control the photosensitive pixel to perform light sensing, the first scanning driving signal is provided for the photosensitive pixel of the next line after the electric signal generated in the light sensing is output. Here, the photosensitive pixels in the next line are not limited to the photosensitive pixels in a line adjacent to the photosensitive pixels in the current line, and may also refer to the photosensitive pixels in alternate lines.

Specifically, referring to fig. 6, fig. 6 shows a timing when the photosensitive device shown in fig. 4 performs light sensing in a line-by-line sensing, line-by-line readout manner. t is t₁At the moment, providing a first scanning driving signal to the photosensitive pixels of the 1 st line to drive the photosensitive pixels of the 1 st line to perform light sensing, t₂At the moment, providing an output control signal to the photosensitive pixel of the 1 st row to control the photosensitive pixel of the 1 st row to output a photosensitive signal；t₃At the moment, providing a first scanning driving signal to the photosensitive pixels of the 2 nd row to drive the photosensitive pixels of the 2 nd row to perform light sensing, t₄At time, an output control signal is provided to the photosensitive pixel of row 2 to control the photosensitive pixel of row 2 to output a photosensitive signal …, and so on, t_2m-1Providing a first scanning driving signal to the m-th line of photosensitive pixels to drive the m-th line of photosensitive pixels to perform light sensing, t_2mAt the moment, an output control signal is provided to the photosensitive pixel of the mth row to control the photosensitive pixel of the mth row to output a photosensitive signal.

Further, in some embodiments, the first driving circuit 241 is further configured to: providing a first scanning driving signal to photosensitive pixels of a current line when a preset time is reached; the predetermined time is at least one clock cycle.

Specifically, since the photosensitive signals in the photosensitive pixels 22 are output under the control of the output control signal, the photosensitive times of the photosensitive pixels in different rows may overlap, that is, when the photosensitive pixels in a current row perform photosensitive sensing, the first scanning driving signal may be provided to the photosensitive pixels in a next row to drive the photosensitive pixels to perform photosensitive sensing. Here, the photosensitive pixels in the next line are not limited to the photosensitive pixels in a line adjacent to the photosensitive pixels in the current line, and may also refer to the photosensitive pixels in alternate lines.

Referring to fig. 7, fig. 7 shows a timing when the photosensitive device shown in fig. 4 performs light sensing in a rolling sensing, line-by-line readout manner. t is t₁₁Time of day, providing the firstScanning a driving signal to the photosensitive pixels of the 1 st row to drive the photosensitive pixels of the 1 st row to perform light sensing, t₁₂At the moment, providing a first scanning driving signal to the photosensitive pixels of the 2 nd row to drive the photosensitive pixels of the 2 nd row to perform light sensing, t₁₃At the moment, providing a first scanning driving signal to the photosensitive pixels in the 3 rd row to drive the photosensitive pixels in the 3 rd row to perform light sensing, and so on, t_1mAt the moment, a first scanning driving signal is provided for the photosensitive pixels of the mth row so as to drive the photosensitive pixels of the mth row to perform light sensing. And when the photosensitive pixels of each row perform light sensing and reach a preset time, providing output control signals to the photosensitive pixels of the row. E.g. t₂₁Providing an output control signal to the photosensitive pixel of the 1 st row at a moment to control the photosensitive signal output of the photosensitive pixel of the 1 st row, t₂₂And providing output control signals to the photosensitive pixels of the 2 nd row at the moment so as to control the photosensitive signals output by the photosensitive pixels of the 2 nd row.

Therefore, the photosensitive device 20 performs the photosensitive operation in a short time, and the time for all photosensitive pixels to wait for reading the photosensitive signals is consistent, i.e., the influence of charge leakage on photosensitive signal acquisition is solved, thereby improving the sensing accuracy.

In some embodiments, with continued reference to fig. 4, the photo-sensing driving circuit further includes a signal processing unit 25, the data lines of the photo-sensing device 20 shown in fig. 4 are all connected to the signal processing unit 25, and the signal processing unit 25 can be integrated into a detection chip through a silicon process. Of course, the signal processing unit 25 and the photosensitive driving unit 24 may be integrated into a single processing chip. Specifically, the signal processing unit 25 is configured to read an electrical signal generated when the light sensing unit 222 performs light sensing, and obtain predetermined biometric information of a target object contacting or approaching the light sensing panel according to the read electrical signal. It is understood that, in order to acquire an accurate and effective electrical signal, the signal processing unit 25 may read the electrical signal generated when the light sensing unit 222 performs light sensing for a plurality of times within the 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 corresponding data line. However, alternatively, each processing channel may be correspondingly connected to at least two data lines, and the electrical signals on one data line are selected to be read each time, then the electrical signals on the other data line are selected again in a time-division multiplexing manner, and so on until the electrical signals on all the data lines are read. In this way, the number of processing lanes can be reduced, thereby saving the cost of the photosensitive device 20.

Referring to fig. 8, fig. 8 shows another circuit structure of a photosensitive pixel 22 in fig. 1. In the embodiment of the invention, a photosensitive pixel 22 has a first input end In1 ', a second input end In 2', a third input end In3 ', a fourth input end In4, a first output end Out 1' and a second output end Out 2. The light sensing control signal includes a first scan driving signal. Specifically, the light-sensing pixel 22 includes a sensing unit and a signal output unit 223'. The sensing unit specifically comprises a switch unit 221 'and a photosensitive unit 222'. The switch unit 221 'receives a reference signal Vref through a third input terminal In 3', and In addition, the switch unit 221 'receives a first scan driving signal through a first input terminal In 1' and transmits the reference signal Vref to the photosensitive unit 222 'to drive the photosensitive unit 222' to perform photo sensing when receiving the first scan driving signal, and the signal output unit 223 'receives an output control signal through a second input terminal In 2' and receives a constant electrical signal Is through a fourth input terminal In4, so that upon receiving the output control signal, the constant electrical signal Is converted into two different electrical signals according to an electrical signal generated when the photosensitive unit 222 'performs photo sensing and Is output from a first output terminal Out 1' and a second output terminal Out 2.

Optionally, the first scan driving signal and the output control signal are both pulse signals, and a duration of a high level signal in the first scan driving signal is a first predetermined time, and a duration of a high level signal in the output control signal is a second predetermined time. Correspondingly, when receiving the first scan driving signal, the switching unit 221' is turned on according to the high level signal and turned off according to the low level signal. Therefore, the light sensing unit 222 'receives the reference signal Vref transmitted from the switch unit 221', and starts to perform light sensing when the first predetermined time is reached.

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 optical sensing, that is, receive an optical signal, and convert the received optical signal into a corresponding electrical signal; the second branch circuit 2222 is used for maintaining the electric signal of the first end of the second branch circuit 2222 at the amplitude of the reference signal Vref. Specifically, the photosensitive unit 222 'is similar to the photosensitive unit 222 shown in fig. 2, and the photosensitive unit 222' further includes a second capacitor c2 in addition to the structure of the photosensitive unit 222 shown in fig. 2, and the first capacitor c1 and the second capacitor c2 are the first branch circuit 2221 of the photosensitive unit 222 ', and the second branch circuit 2222 of the photosensitive unit 222'.

Regarding the first branch circuit 2221, it is defined that the cathode of the photodiode D1 and the first plate of the first capacitor c1 are the first terminal of the first branch circuit 2221, and the anode of the photodiode D1 and the second plate of the first capacitor c1 are the second terminal of the first branch circuit 2221. The operation of the first branch circuit 2221 can be implemented as described above. 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 used for receiving a fixed electrical signal, such as the ground signal NGND. The reference signal Vref charges the second capacitor c2, so 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, here, the first plate of the second capacitor c2 is defined as the first end of the second branch circuit 2222, and the second plate of the second capacitor c2 is defined as the second end of the second branch circuit 2222.

Further, in some embodiments, the switching unit 221 includes a fourth transistor T4 and a fifth transistor T5. The fourth transistor T4 and the fifth transistor T5 are, for example, but not limited to, any one or more of a triode, a MOS transistor, and a thin film transistor. Taking a MOS transistor as an example, 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 a gate of the MOS transistor, the seventh transfer electrode S7 is a drain of the MOS transistor, and the eighth transfer electrode S8 is a source of the MOS transistor. The fifth transistor T5 includes a fifth control electrode C5, a ninth transfer electrode S9 and a tenth transfer electrode S10, wherein the fifth control electrode C5 is a gate of a MOS transistor, the ninth transfer electrode S9 is a drain of the MOS transistor, and the tenth transfer electrode S10 is a source of the MOS transistor.

The fourth control electrode C4 and the fifth control electrode C5 are both connected to the first input terminal In 1' and are configured to receive the first scan driving signal; the seventh transmission electrode S7 and the ninth transmission electrode S9 are both connected to the third input terminal In 3' for receiving the reference signal Vref; the eighth transmitting electrode S8 is connected to the first end of the first branch circuit 2221 of the light sensing unit 222 'for transmitting the reference signal Vref to the first branch circuit 2221 of the light sensing unit 222' when the fourth transistor T4 is turned on; the tenth transmitting electrode S10 is connected to the first terminal of the second branch circuit 2222 of the light sensing unit 222 'for transmitting the reference signal Vref to the second branch circuit 2222 of the light sensing unit 222' when the fifth transistor T5 is turned on.

In some embodiments, the signal output unit 223' in the present embodiment includes a sixth transistor T6 and a conversion circuit 2231. The sixth transistor T6 is, for example, but not limited to, any one or more of a triode, a MOS transistor, and a thin film transistor. Taking a MOS transistor as an example, the sixth transistor T6 includes a sixth control electrode C6, an eleventh transmission electrode S11 and a twelfth transmission electrode S12, wherein the sixth control electrode C6 is a gate of the MOS transistor, the eleventh transmission electrode S11 is a drain of the MOS transistor, and the twelfth transmission electrode S12 is a source of the MOS transistor. The sixth control electrode C6 is connected to the second input terminal In 2' for receiving the output control signal; the eleventh transmission electrode S11 Is connected to the fourth input terminal In4 for receiving a constant current signal Is, and the twelfth transmission electrode S12 Is connected to the switching circuit 2231. The sixth transistor T6 Is turned on according to the output control signal to transmit the constant current signal Is to the switching circuit 2231.

Further, the switching circuit 2231 includes a differential pair transistor having three input terminals and two output terminals, wherein one input terminal of the differential pair transistor Is connected to the twelfth transmission electrode S12 of the sixth transistor T6, and Is configured to receive the constant current signal Is transmitted by the sixth transistor T6; the other two input terminals are correspondingly connected to the first terminal of the first branch circuit 2221 (i.e., the cathode of the photodiode D1 and the first plate of the first capacitor c 1) and the first terminal of the second branch circuit 2222 (i.e., the first plate of the second capacitor c 2); the two output terminals convert the constant current signal Is into two different current signals Ip and In according to the electrical signal Vp at the first terminal of the first branch circuit 2221 and the electrical signal Vn at the first terminal of the second branch circuit 2222, 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 seventh transistor T7 and an eighth transistor T8. The seventh transistor T7 and the eighth transistor T8 are, for example, but not limited to, any one or more of a triode and a MOS transistor. Taking a MOS transistor as an example, the seventh transistor T7 includes a seventh control electrode C7, a thirteenth transfer electrode S13 and a fourteenth transfer electrode S14, wherein the seventh control electrode C7 is a gate of the MOS transistor, the thirteenth transfer electrode S13 is a drain of the MOS transistor, and the fourteenth transfer electrode S14 is a source of the MOS transistor. The eighth transistor T8 includes an eighth control electrode C8, a fifteenth transmission electrode S15 and a sixteenth transmission electrode S16, wherein the eighth control electrode C8 is a gate of a MOS transistor, the fifteenth transmission electrode S15 is a drain of the MOS transistor, and the sixteenth transmission electrode S16 is a source of the MOS transistor.

The seventh control electrode C7 of the seventh transistor T7 is connected to the first terminal of the first branch circuit 2221 (e.g., the first plate of the first capacitor C1); the thirteenth transfer electrode S13 Is connected to the twelfth transfer electrode S12 of the sixth transistor T6 and Is configured to receive the constant current signal Is transmitted from the sixth transistor T6; the fourteenth transmitting electrode S14 is connected to the first output terminal Out 1' for outputting a current signal Ip. The eighth control electrode C8 of the eighth transistor T8 is connected to the first terminal of the second branch circuit 2222 (e.g., the first plate of the second capacitor C2); the fifteenth transmission electrode S15 Is connected to the twelfth transmission electrode S12 of the sixth transistor T6 and Is configured to receive the constant current signal Is transmitted from the sixth transistor T6; the sixteenth transmission electrode S16 is connected to the second output terminal Out2 for outputting another current signal In.

Further, the seventh transistor T7 and the eighth transistor T8 form a differential pair transistor, which is in a balanced state when the voltage Vp at the seventh control electrode C7 of the seventh transistor T7 and the voltage Vn at the eighth control electrode C8 of the eighth transistor T8 are equal, and the fourteenth transmission electrode S14 of the seventh transistor T7 and the sixteenth transmission electrode S16 of the eighth transistor T8 output current signals with equal amplitudes. When there is a voltage difference between the voltage Vp at the seventh control electrode C7 of the seventh transistor T7 and the voltage Vn at the eighth control electrode C8 of the eighth transistor T8, the differential pair transistor outputs two differential electrical signals having different amplitudes. By inputting the two differential electrical signals with different amplitudes to the two input ends of the differential amplifier, corresponding amplified electrical signals can be obtained.

Referring to FIG. 9, FIG. 9 shows the timing of signals at the nodes of the photosensitive pixel 22 of FIG. 8 performing light sensing, where Vp is the voltage signal at the cathode of the photodiode D1 and the first plate of the first capacitor c 1; vn is a voltage signal on the first plate of the second capacitor c 2; ip is a current signal output from the fourteenth transfer electrode S14 of the seventh transistor T7, and In is a current signal output from the sixteenth transfer electrode S16 of the eighth transistor T8.

At time T1, the first scan driving signal is input through the first input terminal In 1', and the fourth transistor T4 and the fifth transistor T5 are turned on according to a high level signal.

When the fourth transistor T4 is turned on, the reference signal Vref is transmitted to the cathode of the photodiode D1 and the first plate of the first capacitor c1 through the seventh transmission electrode S7 and the eighth transmission electrode S8. Since the photodiode D1 has an equivalent capacitance therein, the reference signal Verf charges the equivalent capacitance in the photodiode D1, so that the voltage Vp at the cathode of the photodiode D1 gradually rises and remains unchanged after reaching the voltage value of the reference signal Vref. In addition, the reference signal Vref charges the first capacitor c1, so that 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.

When the fifth transistor T5 is turned on, the reference signal Vref is transmitted to the first plate of the second capacitor c2 through the ninth transmission electrode S9 and the tenth transmission electrode S10, so as to charge the second capacitor c2, and the voltage Vn across the second plate of the second 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 changes from a high level signal to a low level signal, so the first input terminal In1 changes to a low level signal, and the fourth transistor T4 and the fifth transistor T5 are both turned off. When the fourth transistor T4 is turned off, a discharge loop is formed between the equivalent capacitor and the first capacitor c1 and the photodiode D1. The photosensitive unit 222' starts performing light sensing. At this time, when the photodiode D1 is irradiated with the optical signal, a current signal proportional to the optical signal is generated in the photodiode D1, and thus the voltage Vp at the cathode of the photodiode D1 gradually decreases. Further, the stronger the optical signal, the faster the voltage Vp decreases. When the fifth transistor T5 is turned off, the voltage Vn on the first plate of the second capacitor c2 remains unchanged because the second capacitor c2 cannot form a discharge loop.

At time T3, the control signal Is inputted and outputted through the second input terminal In 2', the sixth transistor T6 Is turned on according to the high level signal, and the constant current signal Is transmitted to the switching circuit 2231. The conversion circuit 2231 outputs two current signals having different amplitudes according to the voltage difference between the voltage Vp and the voltage Vn. As the voltage Vp drops, the voltage difference between the voltage Vn and the voltage Vp becomes larger and larger, so that the differential pair transistor outputs two current signals of different magnitudes. As shown In fig. 9, the amplitude of the current signal Ip output by the first output terminal Out 1' decreases with the decrease of the voltage Vp, and the amplitude of the current signal In output by the second output terminal Out2 gradually increases from a low level to a current value corresponding to the voltage Vn and then increases with the decrease of the current signal Ip due to the characteristics of the differential pair transistor. Moreover, if the two paths of differential signals are input into the differential amplifier and then output electrical signals, the electrical signals are amplified by one time compared with one path of electrical signals, and therefore the signal amplification effect is achieved.

At time T4, the output control signal changes from a high level signal to a low level signal, so that the second input terminal In2 'changes to a low level signal, the sixth transistor T6 is turned off, and the first output terminal Out 1' and the second output terminal Out2 stop outputting electrical signals and change to low level signals. The time between the time t4 and the time t3 is defined as a second predetermined time Δ t1, and during this time, the magnitude of the light sensing signal generated by the light sensing performed by the light sensing unit 222 'can be obtained by acquiring corresponding current signals from the first output end Out 1' and the second output end Out2, and according to the two current signals, the biometric information of the target object can be generated.

Further, the second predetermined time Δ t1 may be a fixed value or a variable value. Since the larger the optical signal received by the photodiode D1, the faster the voltage Vp is decreased, the magnitude of Δ t1 is adjusted according to the intensity of the received optical signal in order to accurately and effectively acquire the photo-reception signal. Specifically, the greater the intensity of the optical signal, the shorter Δ t 1; the smaller the intensity of the optical signal, the longer Δ t 1.

Further, the interval between the time t3 and the time t2 cannot be too long or too short, so as to ensure that the photosensitive signal is output effectively in time. Since the light sensing unit 222 ' starts to perform light sensing at time t2, i.e., a corresponding electrical signal is about to be generated, the light sensing signal may be output in time if the interval is too long, and the light sensing unit 222 ' may not be able to generate an effective light sensing signal if the interval is too short, the electrical signal generated by the light sensing unit 222 ' can be controlled to be output in time and effectively.

The photosensitive pixel 22 of the embodiment of the present invention can ensure timely and effective output of the photosensitive signal through output control of the photosensitive signal, and the current signal generated by the photosensitive unit 222 performing the photosensitive operation is output in the form of two differential signals through the conversion circuit 2231, so that amplification of the electrical signal is achieved, and the sensing accuracy of the photosensitive device 20 is improved. In addition, since the two paths of differential signals are both current signals, the anti-interference capability of the signals is improved relative to the output of voltage signals, and the sensing precision of the photosensitive device 20 is further improved.

Further, referring to fig. 10, fig. 10 shows a connection structure between a photosensitive pixel and a scan line, a data line and a signal reference line in a photosensitive device according to another embodiment of the present invention, and the photosensitive pixel has the circuit structure shown in fig. 8. 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 scanning line group comprises a first scanning line group consisting of a plurality of first scanning lines and a second scanning line group consisting of a plurality of second scanning lines, the data line group comprises a plurality of first data lines, a plurality of second data lines and a plurality of third data lines, and the signal reference line group comprises 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, so that the photosensitive array 201 includes m × n photosensitive pixels in total. The number of scan line groups, data line groups, and signal reference line groups connected to the photosensitive pixels 22 are set correspondingly. Specifically, the first scan line group includes m first scan lines arranged at intervals in the Y direction, such as G11, G12, … G1m, and m second scan lines arranged at intervals in the Y direction, such as G21, G22, … G2 m. The signal reference line group includes m signal reference lines, and the m signal reference lines are arranged at intervals in the Y direction, for example, L1, L2, … Lm. The data line group comprises n first data lines, n second data lines and n third data lines, and the n first data lines are arranged at intervals along the X direction, such as S11, S12, … S1 n; the n second data lines are also arranged at intervals in the X direction, such as S21, S22, … S2 n; the n third data lines are also arranged at intervals in the X direction, for example, S31, S32, … S3 n. Of course, the scan line group, the data line group and the signal reference line group of the light sensing device 20 may be distributed in other regular or irregular manners. In addition, the first scanning line, the second scanning line, the signal reference line, the first data line, the second data line and the third data line are all conductive, so that all lines at the crossing positions are isolated through insulating materials.

Specifically, m first scan lines are correspondingly connected to the first input terminals In1 'of the plurality of photosensitive pixels 22, m second scan lines are correspondingly connected to the second input terminals In 2' of the plurality of photosensitive pixels 22, m signal reference lines are correspondingly connected to the third input terminals In3 'of the plurality of photosensitive pixels 22, n first data lines are correspondingly connected to the first output terminals Out 1' of the plurality of photosensitive pixels 22, n second data lines are correspondingly connected to the second output terminals Out2 of the plurality of photosensitive pixels 22, and the third data line is connected to the fourth input terminal In4 of the photosensitive pixel 22. The first scanning line, the second scanning line and the signal reference line are all led out from the X direction, and the first data line and the second data line are led out from the Y direction.

In some embodiments, the photosensitive device 20 further includes a photosensitive driving circuit, which is configured to sequentially drive the plurality of photosensitive pixels to perform photosensitive sensing; and after the photosensitive pixel starts to perform light sensing, controlling the photosensitive pixel to perform electric signal output generated during light sensing.

In some embodiments, with reference to fig. 10, the photo-sensing driving circuit includes a photo-sensing driving unit 24, and the first scan line, the second scan line, and the signal reference line of the photo-sensing device 20 are all connected to the photo-sensing driving unit 24. Referring to fig. 11, fig. 11 shows functional modules of a photosensitive driving unit according to an embodiment of the invention. The photosensitive driving unit 24 includes a first driving circuit 241 ' for providing a first scan driving signal, a second driving circuit 242 ' for providing an output control signal, and a reference circuit 243 ' for providing a reference signal Vref. The circuits of the photosensitive driving unit 24 can be integrated in one control chip through silicon process, but the circuits of the photosensitive driving unit 24 can also be separately formed in different control chips. For example, the first and second driving circuits 241 ' and 242 ' are formed on the same substrate together with the photosensitive pixels 22, and the reference circuit 243 ' is connected to a plurality of signal reference lines of the photosensitive device 20 through a connector (e.g., a flexible circuit board).

In some embodiments, the reference circuit 243 'is used to provide the reference signal Vref, and the reference circuit 243' is selectively electrically connected to the first branch circuit 2221 of the photosensitive unit 222 'through a third switch (e.g., the fourth transistor T4 in the switch unit 221' shown in fig. 8) of the photosensitive pixel 22. When the third switch is closed, the reference signal Vref is transmitted to the first branch circuit 2221 of the corresponding photosensitive unit 222' through the closed third switch. Meanwhile, the reference circuit 243 ' may be selectively electrically connected to the second branch circuit 2222 of the photosensitive unit 222 ' via a fourth switch (e.g., the fifth transistor T5 in the switch unit 221 ' shown in fig. 8) of the photosensitive pixel 22. When the fourth switch is closed, the reference signal Vref is transmitted to the second branch circuit 2222 of the corresponding photosensitive unit 222' through the closed fourth switch.

The first driving circuit 241 'is electrically connected to the first scan line of the photosensitive device 20, and is configured to provide a first scan driving signal to the third switch and the fourth switch in the plurality of photosensitive pixels 22 line by line or in an interlaced manner, so as to control the third switch and the fourth switch to be turned on and off, and when a first predetermined time is reached, control the third switch and the fourth switch to be turned off, so as to drive the photosensitive unit 222' to start performing light sensing.

The second driving circuit 242 'is electrically connected to the second scanning line of the photosensitive device 20, and is configured to provide an output control signal to the fifth switch (e.g., the sixth transistor T6 in the signal output unit 223' shown in fig. 8) after the photosensitive unit 222 'is driven to start performing the light sensing, for example, when the third switch and the fourth switch are turned off and a fourth predetermined time (T3-T2 shown in fig. 9) is reached, so as to control the fifth switch to be turned on, and when the second predetermined time is reached, to control the fifth switch to be turned off, so that 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 the light sensing, and outputs the two different current signals.

Further, the control manner of the plurality of light-sensitive pixels 22 by the first driving circuit 241' is the same as the control manner of the plurality of light-sensitive pixels 22 by the first driving circuit 241. That is, after the first scanning driving signal is provided to the photosensitive pixel of the current row and the output control signal is provided to the photosensitive pixel of the current row to control the electric signal output generated when the photosensitive pixel of the current row performs the light sensing, the first scanning driving signal is provided to the photosensitive pixel of the next row, so that the line-by-line sensing and the line-by-line reading of the photosensitive pixel 22 are realized; or, when a first scanning driving signal is provided for the photosensitive pixels of the current row and a preset time is reached, the first scanning driving signal is provided for the photosensitive pixels of the next row; the predetermined time is at least one clock cycle to effect rolling sensitization of the sensitized pixels 22 for line-by-line readout.

In some embodiments, with continued reference to fig. 10, the photosensitive driving circuit further includes a signal processing unit 25, and the data lines in the photosensitive device 20 shown in fig. 10 are all connected to the signal processing unit 25. Specifically, the third data line is connected to, for example, a constant current source (not shown) for supplying a constant current signal; the first data line and the second data line are connected to a signal processing circuit (not shown), for example. Of course, the signal processing unit 25 and the photosensitive driving unit 24 may be integrated into a single processing chip. The signal processing unit 25 is used for reading an electrical signal generated when the photosensitive unit 222' performs light sensing, and obtaining predetermined biometric information of a target object contacting or approaching the photosensitive device according to the read electrical signal. The signal processing unit 25 may be integrated in one detection chip through a silicon process. It is understood that, in order to acquire an accurate and effective electrical signal, the signal processing unit 25 may read the electrical signal generated when the photosensitive unit 222' performs light sensing for a plurality of times within the 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 corresponding one of the first data line and the second data line. However, alternatively, each processing channel may be correspondingly connected to at least two first data lines and at least two second data lines, and the electrical signals on one first data line and one second data line are selectively read each time in a time-division multiplexing manner, and then the electrical signals on the other first data line and the second data line are selected, and so on until the electrical signals on all the first data lines and the second data lines are read. In this way, the number of processing lanes can be reduced, thereby saving the cost of the photosensitive device 20.

In some embodiments, referring to fig. 12, fig. 12 shows a structure of a photosensitive device according to another embodiment of the invention. The photosensitive device 20 further includes a photosensitive panel 200, the photosensitive panel 200 further includes a substrate 26, and a plurality of photosensitive pixels 22 are disposed on the substrate 26. Alternatively, the photosensitive pixels 22 are distributed in an array. The photosensitive driving circuit is used for driving the photosensitive pixels to perform light sensing and controlling the photosensitive pixels to output electric signals generated when the photosensitive pixels perform the light sensing. The photosensitive pixels 22 are configured to receive the light signals from the top and convert the received light signals into corresponding electrical signals when performing the light sensing, so that the photosensitive areas of the plurality of photosensitive pixels 22 define a sensing area 203, and the areas outside the sensing area 203 are non-sensing areas 202. For the convenience of wiring layout, the non-sensing region 202 is used to set the driving circuits, such as the above-mentioned photosensitive driving circuits, required by the photosensitive pixels 22 to perform the photosensitive. Alternatively, the non-sensing region 202 is used to set a wire bonding area for electrical connections to connect. For example, taking the photosensitive driving circuit shown in fig. 11 as an example, the first driving circuit 241 ' and the second driving circuit 242 ', the reference circuit 243 ' are formed on the substrate 26. Alternatively, the first driving circuit 241 ', the second driving circuit 242 ', and the reference circuit 243 ' are electrically connected to the photosensitive pixels 22 through electrical connectors (e.g., flexible circuit boards).

In some embodiments, the signal processing unit 25 may be selectively formed on the substrate 26 or electrically connected to the photosensitive pixels 22, for example, through an electrical connector (e.g., a flexible circuit board) according to the type of the substrate 26. For example, when the substrate 26 is a silicon substrate, the signal processing unit 25 may be formed on the substrate 26, or may be electrically connected to the photosensitive pixels 22 through a flexible circuit board, for example; when the substrate 26 is an insulating substrate, the signal processing unit 25 needs to be electrically connected to the photosensitive pixels 22, for example, through a flexible circuit board.

In some embodiments, the photosensitive device 20 is a photosensitive chip for sensing biometric information of a target object contacting or approaching the photosensitive device 20. Optionally, the photosensitive device 20 is a fingerprint sensing chip for sensing a fingerprint image of a finger of a user.

Further, based on the above photosensitive device, the embodiment of the invention further provides a light sensing method of the photosensitive device. Referring to fig. 13, fig. 13 shows specific steps of a light sensing method of a light sensing device according to an embodiment of the present invention, the light sensing method of the light sensing device includes the following steps:

step S21, sequentially providing a first scan driving signal to the plurality of photosensitive pixels, so that the photosensitive pixels start to perform light sensing when a first predetermined time is reached;

in step S22, after the photosensitive pixels start to perform the light sensing, output control signals are provided to the plurality of photosensitive pixels to control the output of the electrical signals generated when the photosensitive pixels perform the light sensing.

Further, the step S21 may specifically include: and driving line by line or in an interlaced mode to provide the first scanning driving signal to the plurality of photosensitive pixels so as to drive the photosensitive pixels to carry out light sensing. Therefore, the photosensitive pixels are driven one row at a time to perform light sensing, and the sensing speed is increased.

Specifically, based on the photosensitive device 20 shown in fig. 4 and the photosensitive pixel structure shown in fig. 2, step S21 specifically includes: the first scan driving signal is sequentially supplied to the first switch (e.g., the first transistor T1 in the switch unit 221 shown in fig. 2) in the plurality of photosensitive pixels 22 to control the first switch to be closed, and when the first predetermined time is reached, the first switch is controlled to be opened, so that the photosensitive unit 222 is driven to start performing the light sensing.

Step S22 specifically includes: after the first switch of the switching unit 221 is opened, an output control signal is supplied to a second switch (e.g., a second transistor T2 in the signal output unit 223 shown in fig. 2) of the plurality of photosensitive pixels 22, which is controlled to be closed, so that the photosensitive unit 222 performs optical sensing to generate an electrical signal output.

Based on the photosensitive device shown in fig. 10 and the photosensitive pixel structure shown in fig. 8, step S11 specifically includes: the first scan driving signal is sequentially supplied to the third switch (e.g., the fourth transistor T4 in the switching unit 221 ' shown in fig. 8) and the fourth switch (e.g., the fifth transistor T5 in the switching unit 221 ' shown in fig. 8) in the plurality of photosensitive pixels 22 to control the third switch and the fourth switch to be turned on and off, and when the first predetermined time arrives, the third switch and the fourth switch are controlled to be turned off, so that the photosensitive unit 222 ' is driven to start performing the light sensing.

Step S22 specifically includes: when the third switch and the fourth switch are turned off and a fourth predetermined time (T3-T2 shown in fig. 9) is reached, an output control signal is supplied to the fifth switch (e.g., the sixth transistor T6 in the signal output unit 223 'shown in fig. 8) to control the fifth switch to be turned on, and when the second predetermined time is reached, the fifth switch is controlled to be turned off, so that the conversion circuit 2231 converts the constant current signal into two different current signals according to the electric signal generated when the light sensing unit 222' performs the light sensing, and outputs the two different current signals.

Further, in some embodiments, the step S21 further includes: after the first scanning driving signal is provided to the photosensitive pixel of the current row and the output control signal is provided to the photosensitive pixel of the current row to control the electric signal output generated when the photosensitive pixel of the current row performs the light sensing, the first scanning driving signal is provided to the photosensitive pixel of the next row. Here, the photosensitive pixels in the next line are not limited to the photosensitive pixels in a line adjacent to the photosensitive pixels in the current line, and may also refer to the photosensitive pixels in alternate lines.

Specifically, with continued reference to fig. 6, the photosensitive device performs light sensing in a line-by-line photosensitive, line-by-line readout manner. t is t₁At the moment, providing a first scanning driving signal to the photosensitive pixels of the 1 st line to drive the photosensitive pixels of the 1 st line to perform light sensing, t₂At the moment, providing an output control signal to the photosensitive pixel of the 1 st row so as to control the photosensitive pixel of the 1 st row to output a photosensitive signal; t is t₃At the moment, providing a first scanning driving signal to the photosensitive pixels of the 2 nd row to drive the photosensitive pixels of the 2 nd row to perform light sensing, t₄At time, an output control signal is provided to the photosensitive pixel of row 2 to control the photosensitive pixel of row 2 to output a photosensitive signal …, and so on, t_2m-1Providing the first scanning driving signal to the m-th line of photosensitive pixels to drive the m-th line of photosensitive pixels to perform light sensing，t_2mAt the moment, an output control signal is provided to the photosensitive pixel of the mth row to control the photosensitive pixel of the mth row to output a photosensitive signal.

Further, in some embodiments, the step S21 further includes: providing a first scanning driving signal to photosensitive pixels of a current line when a preset time is reached; the predetermined time is at least one clock cycle.

With continued reference to fig. 7, the light sensing device performs light sensing in a rolling light sensing, line-by-line readout manner. t is t₁₁At the moment, providing a first scanning driving signal to the photosensitive pixels of the 1 st line to drive the photosensitive pixels of the 1 st line to perform light sensing, t₁₂At the moment, providing a first scanning driving signal to the photosensitive pixels of the 2 nd row to drive the photosensitive pixels of the 2 nd row to perform light sensing, t₁₃At the moment, providing a first scanning driving signal to the photosensitive pixels in the 3 rd row to drive the photosensitive pixels in the 3 rd row to perform light sensing, and so on, t_1mAt the moment, a first scanning driving signal is provided to the photosensitive pixels of the mth row to drive the mth rowThe light sensing pixels perform light sensing. And when the photosensitive pixels of each row perform light sensing and reach a preset time, providing output control signals to the photosensitive pixels of the row. E.g. t₂₁Providing an output control signal to the photosensitive pixel of the 1 st row at a moment to control the photosensitive signal output of the photosensitive pixel of the 1 st row, t₂₂And providing output control signals to the photosensitive pixels of the 2 nd row at the moment so as to control the photosensitive signals output by the photosensitive pixels of the 2 nd row.

Further, referring to fig. 14 and 15, fig. 14 shows a structure of an electronic apparatus according to an embodiment of the present invention, fig. 15 shows a cross-sectional structure of the electronic apparatus shown in fig. 14 along the line I-I, and fig. 15 shows only a partial structure of the electronic apparatus. The electronic device comprises the photosensitive device with any one of the implementation structures, and is used for displaying images of the electronic device and sensing the biological characteristic information of a target object contacting or approaching the electronic device.

Examples of the electronic devices include, but are not limited to, consumer electronics, home electronics, vehicle-mounted electronics, financial terminal products, and other suitable types of electronic products. The consumer electronic products include mobile phones, tablet computers, notebook computers, desktop displays, all-in-one computers, and the like. The household electronic products are intelligent door locks, televisions, refrigerators, wearable equipment and the like. The vehicle-mounted electronic products are vehicle-mounted navigators, vehicle-mounted DVDs and the like. The financial terminal products are ATM machines, terminals for self-service business handling and the like. The electronic device shown in fig. 14 is a mobile terminal such as a mobile phone, but the above-mentioned biometric sensing module can also be applied to other suitable electronic products, and is not limited to the mobile terminal such as a mobile phone.

Specifically, the front surface of the mobile terminal 3 is provided with a display device (not shown) including a display panel 300, and a protective cover 400 is disposed over the display panel 300. Optionally, the screen ratio of the display panel 300 is high, for example, more than 80%. The screen occupation ratio refers to a ratio of the display area 305 of the display panel 300 to the front area of the mobile terminal 3. The photosensitive panel 200 in the photosensitive device 20 (see fig. 4 and 10) is a panel structure adapted to the display panel 300 and is correspondingly disposed below the display panel 300. If the display panel 300 is a flexible curved surface, the light sensing panel 200 is also a flexible curved surface. Therefore, the light-sensing panel 200 may have a curved surface structure, instead of a flat surface structure. Thus, the lamination assembly of the photosensitive panel 200 and the display panel 300 is facilitated.

Since the photo sensing panel 200 is located below the display panel 300, the display panel 300 has a light transmission region through which the light signal reflected by the target object passes, so that the photo sensing panel 200 can receive the light signal passing through the display panel 300, convert the received light signal into an electrical signal, and acquire predetermined biometric information of the target object contacting or approaching the electronic device 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 embodiment, the electronic device further uses the optical signal emitted by the display panel 300 to sense the biometric information of the target object, and no additional light source is needed, so that not only the cost of the electronic device is saved, but also the biometric information of the target object in the display area 305 contacting or touching the display panel 300 is sensed. In addition, the photosensitive device 20 can be independently manufactured and then the electronic equipment is assembled, thereby accelerating the manufacturing of the electronic equipment.

When the mobile terminal 3 is in a bright screen state and in the biometric information sensing mode, the display panel 300 emits a light signal. When an object contacts or approaches the display area, the light sensing device 20 receives the light signal reflected by the object, converts the received light signal into a corresponding electrical signal, and obtains predetermined biometric information of the object, such as fingerprint image information, according to the electrical signal. Thus, the light sensing device 20 can sense a target object contacting or approaching any position of the display area.

In some embodiments, the display panel 300 is not limited to an OLED display device, but any display device that can achieve a display effect and has a light-transmitting region through which a light signal passes is within the scope of the present invention. In addition, the display panel 300 may be a bottom emission structure, a top emission structure, or a double-sided light-transmitting structure, and the display screen may be a rigid screen made of a rigid material or a flexible screen made of a flexible material.

In some embodiments, the light sensing panel 200 is used to perform biometric information sensing of a target object anywhere within the display area of the display panel 300. For example, specifically, for example, please refer to fig. 14, fig. 15 and fig. 16 in combination, the display panel 300 has a display area 305 and a non-display area 306, the display area 305 is defined by light emitting areas of all the display pixels 32 of the display panel 300, an area outside the display area 305 is the non-display area 306, and the non-display area 306 is used for setting circuits such as a display driving circuit for driving the display pixels 32 or a circuit bonding area for connecting a flexible circuit board. The photosensitive panel 200 has a sensing region 203 and a non-sensing region 204, the sensing region 203 is defined by the sensing regions of all the photosensitive pixels 22 of the photosensitive panel 200, the region outside the sensing region 203 is the non-sensing region 204, and the non-sensing region 204 is used for setting circuits such as the photosensitive driving unit 24 for driving the photosensitive pixels 22 to perform optical sensing or a circuit bonding region for connecting a 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 larger than or equal to the size of the display region 305, so that the light sensing panel 200 can sense the predetermined biometric information of the target object contacting or approaching any position of the display region 305 of the display panel 300. Further, the area of the photosensitive panel 200 is smaller 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, alternatively, in some embodiments, the area of the photosensitive panel 200 may be larger than that of the display panel 300.

In some embodiments, the sensing region 203 of the light sensing panel 200 may also be smaller than the display region 305 of the display panel 300, so as to realize sensing of the predetermined biometric information of the target object in a local region of the display region 305 of the display panel 300.

Further, the display device is further used for performing touch sensing, and when the display device detects the touch or the proximity of the target object, the position of the control display panel corresponding to the touch area emits light.

However, alternatively, in some embodiments, please refer to fig. 17 and 18, in which fig. 17 illustrates a structure of an electronic device according to an embodiment of the present invention, fig. 18 illustrates a cross-sectional structure of the electronic device illustrated in fig. 17 along a line II-II, and fig. 18 illustrates only a partial structure of the electronic device. The photosensitive module of the embodiment of the invention is applied to a mobile terminal 3, the front of the mobile terminal is provided with a display panel 300, and a protective cover 400 is arranged above the display panel 300. The screen ratio of the display panel 300 is high, for example, 80% or more. The screen occupation ratio refers to a ratio of an actual display area 305 of the display panel 300 to a front area of the mobile terminal. A biological sensing area S for a target object to touch is disposed at a middle-lower position of the actual display area 305 of the display panel 300 for sensing biological characteristic information of the target object, for example, if the target object is a finger, the biological sensing area S is a fingerprint identification area for fingerprint identification. Correspondingly, a photosensitive device 20 is disposed below the display panel 300 at a position corresponding to the fingerprint identification area S, and the photosensitive device 20 is configured to obtain a fingerprint image of a finger when the finger is placed in the fingerprint identification area S. It is understood that the middle-lower position of the display panel 300 is a position where a user can conveniently touch the display panel 300 with a finger when the user holds the mobile terminal. Of course, the touch panel can be arranged at other positions which 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 employs capacitive touch sensing technology, but may be implemented in other ways, such as resistive touch sensing, pressure-sensitive touch sensing, and so on. The touch sensor is configured to determine a touch area of a target object when the target object contacts the protective cover 400, so as to drive display pixels corresponding to the touch area to be lit and light sensing pixels to perform light sensing.

In some embodiments, the touch sensor is integrated with either the protective cover 400, the light-sensing panel 200, or the display panel 300. Through the integrated touch sensor, not only is the touch detection of a target object realized, but also the thickness of the electronic equipment is reduced, and the development of the electronic equipment towards the direction of lightness and thinness is facilitated.

In the description herein, references to the description of the terms "one embodiment," "certain embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and not to be construed as limiting the present invention, and those skilled in the art can make changes, modifications, substitutions and alterations to the above embodiments within the scope of the present invention.

Claims

1. A photosensitive driving circuit is characterized in that: the photosensitive driving circuit is used for sequentially driving the plurality of photosensitive pixels to perform light sensing; and after the photosensitive pixel starts to perform light sensing, controlling the photosensitive pixel to perform electric signal output generated during light sensing.

2. A photo sensing driving circuit according to claim 1, wherein: the photosensitive pixels are distributed on a substrate in an array manner, and the substrate is also provided with a plurality of first scanning lines which are respectively and electrically connected with the photosensitive pixels; the photosensitive driving circuit includes:

3. A photo sensing driving circuit according to claim 2, wherein: the first drive circuit is further configured to:

4. A photo sensing driving circuit according to claim 2, wherein: the first drive circuit is further configured to:

5. A photo sensing driving circuit according to claim 2, wherein: the substrate is also provided with a plurality of second scanning lines which are electrically connected with the plurality of photosensitive pixels; the photosensitive driving circuit further comprises: and the second driving circuit is correspondingly and electrically connected with the second scanning line and is used for providing the output control signal to each photosensitive pixel when each photosensitive pixel starts to perform light sensing and reaches a fourth preset time so as to control the output of an electric signal generated when the photosensitive pixel performs the light sensing.

6. A light sensing driving circuit as defined in claim 5, wherein: the second drive circuit is further configured to: and controlling the light sensing pixels to output the electric signals generated when the light sensing pixels perform light sensing and last for a second preset time.

7. A photo sensing driver circuit according to claim 6, wherein: and the second preset time is dynamically adjusted according to the intensity of the received optical signal.

8. A photo sensing driver circuit according to claim 7, wherein: the greater the intensity of the received optical signal, the shorter the second predetermined time; the smaller the intensity of the received optical signal, the longer the second predetermined time.

9. A photo sensing driving circuit according to claim 2, wherein: the substrate is also provided with a data line electrically connected with the plurality of photosensitive pixels; the photosensitive driving circuit further comprises a signal processing unit, wherein the signal processing unit is electrically connected with the data lines and is used for reading the electric signals output by the photosensitive pixels and obtaining preset biological characteristic information of a target object contacting or approaching the photosensitive pixels according to the read electric signals.

10. A light sensing driving circuit as defined in claim 9, wherein: the photosensitive driving circuit is formed on the substrate or is electrically connected with the plurality of photosensitive pixels through an electrical connecting piece; or, a part of circuits of the photosensitive driving circuit is formed on the substrate, and the other part of circuits is electrically connected with the plurality of photosensitive pixels through a connecting piece.