TWI691906B - Arbitrary position fingerprint detection circuit and electronic device - Google Patents

Abstract

An arbitrary position fingerprint detection circuit, including a control unit, a gate drive unit, a multiplexer unit and a signal readout unit, during operation, the control unit controls the gate drive unit to drive at least a light sensor A fingerprint sensing area in the sensor array; the multiplexer unit divides the plurality of source output terminals of the light sensor array into multiple groups, and performs multiplex connection operation on each group of source output terminals to pass each An output terminal outputs a detection signal; and the signal reading unit reads the plurality of detection signals provided by the multiplexer unit through a plurality of signal readers; wherein each detection signal is composed of a The source output terminal is provided or provided by a common connection of at least two of the source output terminals.

Description

Arbitrary position fingerprint detection circuit and electronic device

The invention relates to the technical field of fingerprint detection, in particular to an arbitrary position fingerprint detection circuit and an electronic device.

Biometric identification (Biometric identification) is based on the collection of inherent physiological characteristics of the human body as the basis for identification of individual organisms, such as: iris (Iris), face (Face), voiceprint (Voice), and fingerprint (Fingerprint) and other physiological characteristics Among them, fingerprint identification technology has been widely seen in various electronic products. Currently, commercially available fingerprint identification devices can be divided into optical, pressure, ultrasonic, and capacitive types. Among them, general optical fingerprint identification devices include a light emitting source, a photodetector array, a fingerprint detection circuit, and fingerprint identification Operation function. It is worth mentioning that the under-screen optical fingerprint recognition device directly uses the self-luminous screen as the light source, and the light-emitting element is omitted in the structural composition.

Please refer to FIG. 1, which shows an architecture diagram of a conventional fingerprint detection circuit. As shown in FIG. 1, a fingerprint detection circuit 1 ′ includes a control unit 10 ′, a gate drive unit 11 ′ electrically connected to the drive side of the photodetector array 2 ′ of a display panel 3 ′ and electrical connection A signal readout unit 12' to the detection side of the photodetector array 2'of the display panel 3'. Please also refer to FIG. 2, which shows an internal structure diagram of the photodetector array 2 ′ of FIG. 1. As shown in FIG. 2, the photodetector array 2 ′ includes n×m photodetectors, n and m are both integers greater than 1, and each of the photodetectors includes a TFT switch 21 ′ and a photodiode 22' and a parasitic capacitance 23'. It is worth noting that the gates of the n×m TFT switches 21′ of the photodetector array 2′ are coupled to the gate driving unit 11′ through the gate lines 211′-21n′, and the photodetector array 2′ The sources of the n×m TFT switches 21′ are coupled to the signal readout unit 12′ through the source lines 221′-22m′.

Before starting the fingerprint detection, the gate driving unit 11' will sequentially input the driving signals to the gate lines 211'-21n' according to the timing control of the control unit 10', and the control unit 10' will control the signal reading unit 12 'In order to discharge the parasitic capacitances 23' through the source lines 221'-22m' in order to clear the accumulated charges in the parasitic capacitances 23'. After completing the charge removal of all parasitic capacitances 23', the gate driving unit 11' turns off all the TFT switches 21', and then starts the fingerprint detection process. Under the action of external light, the photodiode 22' in the photodetector array 2'will generate a photocurrent, and the photocurrent will accumulate charge on the parasitic capacitance 23'. After waiting for the accumulated charge time (about tens of ms to hundreds of ms), the gate driving unit 11' sequentially inputs the driving signal to the gate line 211'-21n1' again, and the signal reading unit 12' sequentially The ground reads the voltage of each parasitic capacitance 23' through the source line 221'-22m'.

The photodetector array 2'shown in Figs. 1 and 2 occupies only a partial area of a display screen. That is to say, for an under-screen optical fingerprint identification device, only this small area composed of the photodetector array 2'can perform fingerprint detection. In order to provide a fingerprint detection function with a larger area, a conventional combination scheme using multiple gate drive units 11' and multiple signal readout units 12' has been known. Please refer to FIG. 3, which illustrates an architectural diagram of another conventional fingerprint detection circuit.

As shown in FIG. 3, 2×3 photodetector arrays 2′ are correspondingly planned in 2×3 blocks, and the fingerprint detection circuit 1′ includes: a control unit 10′, electrically connected to 2× Two gate drive units 11' on the driving side of the three photodetector arrays 2', and three signal readout units 12' electrically connected to the detection side of the 2x3 photodetector arrays 2'. According to this, the fingerprint sensing area can be increased by 6 times. However, for the fingerprint detection circuit 1', the signal driving and signal detection areas are also increased by a factor of 6 at the same time, so it is bound to take more time to complete the fingerprint detection process for all areas. In addition, it is not easy for the control unit 10' to coordinately control the two gate drive units 11' and the three signal readout units 12', and the data that the back-end data processing unit must process The amount will also double. In other words, the architecture shown in Figure 3 is obviously not ideal, and has many practical defects.

Therefore, there is an urgent need for a novel fingerprint detection circuit in the art.

An object of the present invention is to provide an arbitrary position fingerprint detection circuit, which can greatly reduce the number of traces between the panel and the chip and reduce the number of pins of the chip through a multiplex circuit, thereby facilitating the design of full-screen fingerprint detection with a narrow border .

Another object of the present invention is to provide an arbitrary position fingerprint detection circuit, which can improve the fingerprint detection speed by selectively driving the gate line corresponding to a fingerprint sensing area.

To achieve the above objective, a fingerprint detection circuit is proposed, which is electrically connected to a photo sensor array, the photo sensor array including M×N photo detectors, M gate lines, and N source electrodes Line, where M and N are both integers greater than 1, and the arbitrary position fingerprint detection circuit includes:

A control unit;

A gate drive unit, electrically connected to the control unit, and electrically connected to the M gate lines;

A multiplexer unit, electrically connected to the control unit, and including N switches and J multiplex output terminals, J is an integer greater than 1, wherein each of the switches has a control terminal and a first channel terminal And a second channel end, each of the control ends is coupled to the control unit, each of the first channel ends is coupled to one of the source lines, and each of the multiplexed output ends is connected to a plurality of The second channel end is coupled to provide a detection signal when each of the multiplexed output ends is selected; and

A signal reading unit, which is electrically connected to the control unit and the multiplexer unit, and includes J signal reading units;

During operation, the control unit controls the gate driving unit to drive at least a plurality of the gate lines corresponding to a fingerprint sensing area in the photo sensor array, and the signal reading unit passes through the J The signal reader reads the J detection signals provided by the multiplexer unit, wherein the fingerprint sensing area is located in at least one detection area in the light sensor array.

In a possible embodiment, the plurality of switches to which the signal readers are coupled are adjacent or non-adjacent to each other.

In an embodiment, the at least one detection area is in at least one sub-screen of a display screen.

In an embodiment, the control terminals of at least two of the switches are coupled to the same switch control signal.

In one embodiment, the gate driving unit sequentially drives a plurality of the gate lines in each detection area according to a scanning direction.

In an embodiment, the gate driving unit drives a portion of the at least one detection area covering the fingerprint sensing area at a first scanning speed, and drives the at least one detection area at a second scanning speed The part of the fingerprint sensing area is not covered, and the second scanning speed is higher than the first scanning speed.

In an embodiment, the gate driving unit drives two detection areas covering part of the fingerprint sensing area in two scanning directions opposite to each other.

In one embodiment, the gate driving unit includes a gate driving chip or an on-board integrated gate driving circuit.

In addition, the present invention further provides an electronic device having a fingerprint detection circuit at any position as described above.

In one embodiment, the electronic device may be any one of the following: a smart phone, a tablet computer, a notebook computer, an integrated computer, a door phone, an electronic door lock, or a fingerprint identification device.

In order to enable your review committee to further understand the structure, features, purposes, and advantages of the present invention, the drawings and detailed description of the preferred specific embodiments are attached as follows.

FIG. 4 is a schematic diagram of an embodiment of an arbitrary position fingerprint detection circuit of the present invention. As shown in FIG. 4, the fingerprint detection circuit 1 at any position of the present invention is electrically connected to a photo sensor array 2 of a display panel 3, and the photo sensor array 2 includes M×N photo detectors and M strips Gate line and N source lines, where M and N are integers greater than 1.

Continuing to refer to FIG. 4, the arbitrary position fingerprint detection circuit 1 of the present invention mainly includes: a control unit 10, a gate driving unit 11, a multiplexer unit 12, and a signal reading unit 13. And, please also refer to FIG. 5, which illustrates an architectural diagram of an embodiment of the photo sensor array, multiplexer unit, and signal readout unit of FIG. 4. According to the design of the present invention, the gate driving unit 11 is electrically connected to the control unit 10 and electrically connected to the plurality of gate lines. The multiplexer unit 12 is electrically connected to the control unit 10, and includes N switches 121 and J multiplex output terminals, J is a positive integer greater than 1, and the N switches 121 each have a control terminal, a The first channel end and a second channel end are electrically connected to the source line through the first channel end, and each of the multiplexed output ends is coupled to the plurality of second channel ends. On the other hand, the signal reading unit 13 is electrically connected to the control unit 10 and the multiplexer unit 12. As can be seen from FIG. 5, the signal reading unit 13 includes J signal readers 131, and each of the signal readers 131 is coupled to each of the multiplexed output terminals. For example, if the number of source lines is 1440, the multiplexer unit 12 will have 1440 switches 121 coupled to each source line through its first channel end. In the case where the signal reading unit 13 has 200 signal receiving channels, the multiplexer unit 12 will have 200 multiplexing output terminals respectively coupled to the 200 signal reading units 131. In this case, a signal reader 131 is coupled to at least seven switches 121 through the multiplex output terminal. Engineers familiar with the design and manufacture of display circuits should be able to infer that the number of the gate lines and the source lines varies with different resolutions of the display panel 3 and is not a fixed value.

At the same time, FIG. 5 shows that the N switches 121 coupled to the signal readout unit 13 are not adjacent to each other; for example, the 1,201,401,...,1401 switches 121 pass through the multiplexer unit 12 One multiplexer output is simultaneously coupled to the first signal reader 131, and the second, second, 202, 402, ..., 1402 switches 121 are simultaneously coupled through the other multiplexer output of the multiplexer unit 12 To the second signal reader 131. By analogy, all 1440 source lines are connected to the corresponding first channel ends of the switches 121, and the second channel ends of the N switches 121 are connected through the J multiplex output terminals of the multiplexer unit 12. To the corresponding signal reader 131. Here, the signal reader 131 is an analog front end (AFE) element.

Please refer to FIG. 6 again, which shows a connection diagram of the switch and the signal reader of FIG. 5. As shown in FIGS. 5 and 6, the control unit 10 is coupled to a control terminal of the N switches 121 of the multiplexer unit 12. In addition, according to the control of the control unit 10, the gate driving unit 11 sequentially inputs a driving signal into the M gate lines; at the same time, the control unit 10 transmits a switch control signal to the N switches 121 to make the signal read The output unit 13 can read out the detection signal from a detection area 5 through the N number of switches 121 and the N source lines under the control of the control unit 10. SEL<0>, SEL<1>, SEL<2>, and SEL<3> in FIG. 6 are the switch control signals, IO<0>, IO<1>, IO<2>, and IO <3> is the detection signal. Furthermore, as can be seen from the example of FIG. 6, one detection area 5 above the photo sensor array 2 can be dynamically and arbitrarily composed of M (ie, four) gate lines and N (ie, four) ) Determined by the source line. In this design, when the same four gate lines are fixed, the detection area 5 can be moved by one pixel by changing one source line (one switch 121) to the right.

It is worth noting that FIG. 6 shows that each switch 121 receives a set of switch control signals transmitted by the control unit 10 through its control terminal, that is, each switch 121 must be electrically connected to the control unit 10 through a line. It is foreseeable that this method will cause the circuit layout of the circuit chip of the fingerprint detection circuit 1 at any position to become huge and complicated. Therefore, please refer to FIG. 7, which illustrates another connection diagram of the switch and the signal reader of FIG. 5, in which P switches 121 are coupled to the same set of switch control signals, and the P value is greater than 2. For example, in FIG. 7, two switches 121 are coupled to the same set of switch control signals. In this design, when the same four gate lines are fixed, the control unit 10 can control each of the switches 121 with the switch control signal, so that the detection area 5 moves to the right by two pixels. In short, after P switches 121 are coupled to the same set of switch control signals, the circuit layout of the circuit chip of the fingerprint detection circuit 1 at any position can be simplified and the area of the circuit layout can be reduced.

FIG. 8a shows a connection diagram of the photo sensor array, multiplexer unit and signal readout unit of FIG. 5. FIG. Generally, a single set of signal reading unit 13 will include 200 signal readers (ie, AFE) 131. As shown in FIG. 8a, the control unit 10 can simultaneously control 200 signal readers 131, that is, AFE1~40, AFE41~80, AFE81~120, AFE121~160, and AFE161~200, making the signal readout unit 13 one-time Collect all the detection signals of the source lines. However, it is foreseeable that enabling 200 AFE channels at the same time will cause the power consumption of the circuit chip of the fingerprint detection circuit 1 at any location to be too high (may be close to 1W). Therefore, please refer to FIG. 8b, which illustrates another connection diagram of the photo sensor array, the multiplexer unit, and the signal readout unit of FIG. 5 in a manner of reading 200 signals contained in the signal readout unit 13. The output device (ie, AFE) 131 is divided into several groups, and then the signal readout is controlled in a group-enabled manner.

Although the method of FIG. 8b can effectively reduce the power consumption of the AFE channel, there is a better way to reduce the power consumption of the AFE channel. FIG. 8c illustrates another connection diagram of the photo sensor array, multiplexer unit and signal readout unit of FIG. 5. FIG. Comparing FIG. 8b and FIG. 8c, it can be found that FIG. 8b uses time-sharing and grouping to enable different groups of signal readers (ie, AFE) 131 in the signal reading unit 13, while FIG. 8c uses At the same time, a single group of signal readers 131 inside the signal reading unit 13 is activated. Simply put, the method of FIG. 8c can further save the total amount of the signal reader 131 included in the signal reading unit 13.

It must be known that the signal readout unit 13 (that is, Read out IC, ROIC) has very high requirements for noise, and there are three main sources of noise in a fingerprint identification device: the photodiode of the photo sensor array 2 (photodiode) noise, the ROIC IC's own line noise, and the line parasitics from each source line to each of the signal readers (ie, AFE) 131 in the signal readout unit 13 It can be inferred that the more and longer the connection line between the source line and the signal reader 131, the noise derived from the line parasitic may overshadow the detection signal, resulting in the control unit 10 or the signal processor at the back end The detection signal of the signal reader 131 cannot be recognized.

FIG. 9 illustrates a connection architecture diagram of one of the photo sensor array, the multiplexer unit and the signal readout unit of FIG. 5. In order to reduce the line parasitics, as shown in FIG. 9, the second channel ends of adjacent switches 121 are connected to the same signal reader through a multiplexer output of the multiplexer unit 12 at the same time (Ie, AFE)131. In short, the N switches 121 to which the signal reader 131 is coupled are adjacent. FIG. 5 is a schematic diagram of the connection between the light sensor array and the multiplexer unit in FIG. 5. Please refer to FIG. 9 and FIG. 10 at the same time. After the adjacent switch 121 is connected to the same signal reader (ie, AFE) 131, the connection line is greatly shortened, reducing the line parasitic noise. In addition, FIG. 10 is to dynamically turn on the display switch 121 to express the dynamic connection of each of the signal reader 131 and the source line (ie, IO).

Please continue to refer to FIG. 11, which illustrates a schematic diagram of a sensing operation that divides the photo sensor array of FIG. 5 into three regions, in which the display panel 3 has 3360 gate lines, and M of the gate lines and N of the gate lines The source line determines a detection area 5 of the photo sensor array. In particular, in FIG. 11, we mark the part covered by the finger in the detection area 5 as the attention detection area 5RoI (Region of Interest, RoI). The conventional technique is usually to make the gate driving unit 11 sequentially input the driving signal from the first gate line to the 3360th gate line, but this way will make the entire scanning time increase as the number of gate lines increases lengthen. Therefore, as shown in FIG. 11, the present invention specifically allows the gate driving unit 11 to input the detection area covered by a finger (as indicated by a solid arrow) with the driving signal having a first scanning speed, and to have a The driving signal of the second scanning speed is input to the detection area that is not covered by the finger (as indicated by the dotted arrow); the second scanning speed is higher than the first scanning speed. FIG. 12 shows a working timing diagram corresponding to FIG. 11.

In addition, please refer to FIGS. 13-16 together, wherein FIG. 13 illustrates that the light sensor array of FIG. 5 is implemented in a multi-subscreen manner, and a fingerprint sensing area is located in a scanning sense within a subscreen FIG. 14 shows the implementation of the multi-screen method of the light sensor array of FIG. 5, and a fingerprint sensing area is a schematic diagram of the co-scanning sensing operation across two sub-screens; FIG. 15 The light sensor array of FIG. 5 is implemented in a multi-subscreen manner, and a fingerprint sensing area is a schematic diagram of two reverse scanning sensing operations spanning two sub-screens; and FIG. 16 is a schematic diagram of FIG. 5. The light sensor array is implemented in a multi-sub-screen manner, and a fingerprint sensing area is a schematic diagram of a sensing operation spanning three sub-screens. It is worth noting that in FIG. 15, the two reverse scan sensing operations only scan the fingerprint sensing area 5RoI, and the rest are not scanned.

In addition, according to the above description, the present invention further provides an electronic device having a fingerprint detection circuit at any position as described above, and the electronic device may be any of the following: smart phone, tablet computer, notebook computer, integrated Computer, door phone, electronic door lock, or fingerprint identification device.

In this way, the above is a complete and clear description of the fingerprint detection circuit and electronic device of any position of the present invention; and, through the above, the present invention has the following advantages:

(1) The arbitrary position fingerprint detection circuit of the present invention can greatly reduce the number of traces between the panel and the chip and the number of pins of the chip through a multiplex circuit, thereby facilitating the design of full-screen fingerprint detection with a narrow bezel.

(2) The arbitrary position fingerprint detection circuit of the present invention can improve the fingerprint detection speed by selectively driving the gate line corresponding to a fingerprint sensing area.

It must be emphasized that the aforementioned disclosure in this case is a preferred embodiment, and any part of the modification or modification that originates from the technical idea of this case and is easily inferred by those who are familiar with the art, does not deviate from the patent of this case. Power category.

In summary, regardless of the purpose, means and effects of this case, it shows that it is very different from the conventional technology, and its first invention is practical and practical, and it does meet the patent requirements of the invention. I urge your review committee to investigate and give the patent to the AirPlus as soon as possible. Society is for supreme prayer.

<The present invention>

1: Fingerprint detection circuit at any position

2: Light sensor array

3: display panel

10: control unit

11: Gate drive unit

12: Multiplexer unit

13: Signal readout unit

121: Switch

131: signal reader

5: detection area

5RoI: Focus on detection area

<Xizhi>

1’: Fingerprint detection circuit

2’: Photodetector array

3’: Display panel

10’: Control unit

11’: Gate drive unit

12’: Signal readout unit

21’: TFT switch

22’: Photodiode

23’: Parasitic capacitance

21n’: gate line

21n1’: gate line

212’: Gate line

211’: Gate line

221’: source line

222’: source line

22m1’: source line

22m’: source line

FIG. 1 shows an architecture diagram of a conventional fingerprint detection circuit; FIG. 2 shows an internal architecture diagram of the photodetector array of FIG. 1; FIG. 3 shows an architecture diagram of another conventional fingerprint detection circuit; An architecture diagram of an embodiment of an arbitrary position fingerprint detection circuit of the invention; FIG. 5 illustrates an architecture diagram of an embodiment of the photo sensor array, multiplexer unit, and signal readout unit of FIG. 4; FIG. 6 is a schematic diagram 5 is a connection diagram of a switch and a signal reader; FIG. 7 shows another connection diagram of the switch and the signal reader of FIG. 5; FIG. 8a shows the photo sensor array, multiplexer unit and One connection diagram of the signal readout unit; FIG. 8b shows another connection diagram of the light sensor array, multiplexer unit and signal readout unit of FIG. 5; FIG. 8c shows the light sensor array of FIG. 5, Another connection diagram of the multiplexer unit and the signal readout unit; FIG. 9 shows a connection architecture diagram of one of the light sensor array, the multiplexer unit and the signal readout unit of FIG. 5; FIG. 10 shows the connection diagram of FIG. 5. A schematic diagram of the connection between the photo sensor array and one of the multiplexer units; FIG. 11 shows a schematic diagram of a sensing operation that divides the photo sensor array of FIG. 5 into three areas; FIG. 12 shows a working timing corresponding to FIG. 11 FIG. 13 is a schematic diagram of a sensing operation in which the light sensor array of FIG. 5 is implemented in a multi-screen mode, and a fingerprint sensing area is located in a sub-screen; FIG. 14 shows the light of FIG. 5 The sensor array is implemented in a multi-sub-screen mode, and a fingerprint sensing area is a schematic diagram of a sensing operation spanning two sub-screens; FIG. 15 illustrates the light sensor array of FIG. 5 in a multi-sub-screen Implementation, and a fingerprint sensing area is another schematic diagram of another sensing operation spanning two sub-screens; and FIG. 16 shows that the light sensor array of FIG. 5 is implemented in a multi-sub-screen manner, and a fingerprint sensor The measurement area is a schematic diagram of a sensing operation spanning three sub-screens.

1: Fingerprint detection circuit at any position

2: Light sensor array

3: display panel

10: control unit

11: Gate drive unit

12: Multiplexer unit

13: Signal readout unit

Claims (9)

An arbitrary position fingerprint detection circuit, which is electrically connected to a photo sensor array, the photo sensor array includes M×N photo detectors, M gate lines and N source lines, where M and N are all integers greater than 1, and the arbitrary position fingerprint detection circuit includes: a control unit; a gate drive unit, electrically connected to the control unit, and electrically connected to M of the gate lines; more than one The tool unit is electrically connected to the control unit, and includes N switches and J multiplex output terminals, J is an integer greater than 1, wherein each of the switches has a control terminal, a first channel terminal, and a At the second channel end, each of the control ends is coupled to the control unit, each of the first channel ends is coupled to one of the source lines, and each of the multiplexed output ends is connected to a plurality of The second channel end is coupled to provide a detection signal when each of the multiplexed output terminals is selected; and a signal readout unit, which is electrically connected to the control unit and the multiplexer unit, and includes J Signal reader; during operation, the control unit controls the gate drive unit to drive at least a plurality of the gate lines corresponding to a fingerprint sensing area in the photo sensor array, and the signal is read out The unit reads the J detection signals provided by the multiplexer unit through the J signal readers, wherein the fingerprint sensing area is located in at least one detection area in the light sensor array . The fingerprint detection circuit at any position as described in item 1 of the patent application range, wherein the plurality of switches to which each of the signal readers are coupled are adjacent or non-adjacent to each other. An arbitrary position fingerprint detection circuit as described in item 1 of the patent application range, wherein the at least one detection area is in at least one sub-screen of a display screen. An arbitrary position fingerprint detection circuit as described in item 1 of the patent application range, wherein the control terminals of at least two of the switches are coupled to the same switch control signal. An arbitrary position fingerprint detection circuit as described in item 1 of the patent application range, wherein the gate drive unit sequentially drives a plurality of the gate lines in each detection area according to a scanning direction. The fingerprint detection circuit of any position as described in item 1 of the patent application scope, wherein the gate driving unit drives the portion of the at least one detection area covering the fingerprint sensing area at a first scanning speed, and uses a The second scanning speed drives a portion of the at least one detection area that does not cover the fingerprint sensing area, and the second scanning speed is higher than the first scanning speed. An arbitrary position fingerprint detection circuit as described in Item 1 of the patent application range, wherein the gate drive unit drives two detection areas covering a part of the fingerprint sensing area in two scanning directions opposite to each other. The fingerprint detection circuit of any position as described in item 1 of the patent application scope, wherein the gate drive unit includes a gate drive chip or an on-board integrated gate drive circuit. An electronic device having a fingerprint detection circuit at any position as described in any one of claims 1 to 8 and the electronic device is composed of a smart phone, tablet computer, notebook computer, A device selected by the group consisting of an integrated computer, door phone, electronic door lock and fingerprint identification device.

Images