CN114155563A - Fingerprint identification device - Google Patents
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- CN114155563A CN114155563A CN202010830997.9A CN202010830997A CN114155563A CN 114155563 A CN114155563 A CN 114155563A CN 202010830997 A CN202010830997 A CN 202010830997A CN 114155563 A CN114155563 A CN 114155563A
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Abstract
The invention provides a fingerprint identification device, which comprises a fingerprint electrode layer, a fingerprint identification unit and a fingerprint identification unit, wherein the fingerprint electrode layer comprises a plurality of fingerprint sensing electrodes; the data lines are respectively clamped by a first capacitance eliminating shielding line and a second capacitance eliminating shielding line which correspond to each other, and the fingerprint detection circuit comprises a driving circuit. In the fingerprint detection stage, the fingerprint detection circuit transmits a capacitance excitation signal to a selected fingerprint sensing electrode, inputs a fingerprint sensing signal from the selected fingerprint sensing electrode through the corresponding data line, processes the fingerprint sensing signal through the driving circuit to output a capacitance elimination shielding signal having the same phase as the fingerprint sensing signal, and transmits the capacitance elimination shielding signal to the first capacitance elimination shielding line and the second capacitance elimination shielding line corresponding to the corresponding data line for fingerprint detection operation. Because the first capacitance eliminating shielding line and the second capacitance eliminating shielding line have the same phase voltage with the corresponding data line, the capacitance value between the first capacitance eliminating shielding line and the second capacitance eliminating shielding line can be reduced, and the measurement accuracy of the fingerprint identification device is improved.
Description
Technical Field
The present invention relates to a fingerprint identification device, and more particularly, to a fingerprint identification device with a capacitance-eliminating masking line.
Background
Since the rise of electronic commerce and the development of remote payment are in the thousands of days, the business demand of biometric identification is rapidly expanding, and fingerprint identification is the preferred technology. When borderless mobile display devices have reached a trend, fingerprint recognition within the display screen becomes a goal of hot-door. Solutions such as ultrasonic or under-screen optical detection are expensive and difficult to align, and are difficult to popularize; the capacitive fingerprint recognition technology, which only applies the TFT technology to arrange the sensing electrode and the selection switch on the protective glass, is economical and practical. However, the thickness of the protective glass is hundreds of micrometers, so that the sensing signal is very tiny, and in addition, the data line (data line) is several centimeters long, the area of the data line is far larger than that of a single sensing electrode, and the distance between the data line and the data line is only several micrometers, so that the mutual crosstalk is serious. The traditional method of isolating the conducting electrode from the ground and blocking the noise can generate huge self-capacitance, so that tiny sensing signals are dispersed invisibly and no snow frost is generated. Therefore, how to solve the noise induced by the data lines becomes a difficult problem to be solved.
Disclosure of Invention
The main object of the present invention is to improve the above-mentioned disadvantages of the prior art in which the data lines sense the respective party noise.
In order to achieve the above object, the present invention provides a fingerprint identification device, comprising: a substrate; a fingerprint electrode layer including a plurality of fingerprint sensing electrodes; a transistor switch layer comprising: a plurality of transistor switch groups, wherein the plurality of transistor switch groups correspond to the plurality of fingerprint sensing electrodes in a one-to-one manner; the data lines are respectively corresponding to a first capacitance elimination shielding line and a second capacitance elimination shielding line, so that the first capacitance elimination shielding line and the second capacitance elimination shielding line are clamped with one corresponding data line; the first capacitance eliminating shielding line is positioned between the corresponding data line and a finger to be detected so as to eliminate the influence of the finger to be detected on the corresponding data line; the fingerprint detection circuit transmits a capacitance excitation signal to a selected fingerprint sensing electrode through one of the transistor switch sets, inputs a fingerprint sensing signal from the selected fingerprint sensing electrode through the corresponding data line, processes the fingerprint sensing signal through the driving circuit to output a capacitance elimination shielding signal which is in the same phase with the fingerprint sensing signal, and transmits the capacitance elimination shielding signal to the first capacitance elimination shielding line and the second capacitance elimination shielding line corresponding to the corresponding data line for fingerprint detection operation.
Optionally, the second capacitive reduction shielding line is located on a side of the corresponding data line opposite to the finger to be tested, so as to eliminate the influence of noise from the side on the corresponding data line.
Optionally, the line widths of the first and second capacitive-elimination shielding lines are not less than the line widths of the corresponding data lines.
Optionally, each of the transistor switch sets comprises at least one thin film transistor.
Optionally, the fingerprint detection circuit further applies the capacitive cancellation shielding signal to the fingerprint sensing electrodes around the corresponding data line during the fingerprint detection operation to prevent other sensing signals and noise from being conducted to the corresponding data line through the surrounding fingerprint sensing electrodes.
Optionally, the fingerprint detection circuit is powered by a first power supply, the fingerprint identification device further comprises a display screen powered by a second power supply, and the plurality of fingerprint sensing electrodes are located in a fingerprint detection and touch display area of the display screen.
Optionally, the plurality of fingerprint sensing electrodes are combined into a touch electrode, which is also used for touch detection.
Optionally, there is no common current loop between the first power and the second power during the fingerprint detection operation or the touch detection operation.
Optionally, a plurality of touch electrodes are disposed in a touch display area of the display screen for touch detection, and an area of each touch electrode is more than 50 times an area of the fingerprint sensing electrode.
Optionally, the touch display device further comprises a plurality of virtual data lines arranged in the touch display area, so that the touch display area and the fingerprint detection and touch display area comprising the plurality of fingerprint sensing electrodes have the same or similar transmittance.
Optionally, the substrate is a cover glass of a display screen, a silicon substrate of an integrated circuit, or a polymer film.
Optionally, the plurality of data lines are metal conductive lines or transparent conductors.
Optionally, the plurality of fingerprint sensing electrodes are made of transparent conductive material.
Optionally, the transparent conductor is indium tin oxide.
In the fingerprint identification device, the first capacitance eliminating shielding line, the second capacitance eliminating shielding line and the corresponding data line have the same-phase voltage, so that the capacitance value between the first capacitance eliminating shielding line and the second capacitance eliminating shielding line can be reduced, and the measurement accuracy of the fingerprint identification device is improved.
Drawings
FIGS. 1A to 1C are schematic diagrams respectively illustrating the fingerprint identification device with the vanishing and masking lines according to the present invention.
Fig. 2 is a schematic diagram illustrating an influence of data lines on touch capacitance detection in a conventional fingerprint recognition device.
Fig. 3 is another schematic diagram illustrating an effect of data lines on touch capacitance detection in a conventional fingerprint recognition device.
FIG. 4 is a schematic diagram illustrating the use of a capacitive blanking line to improve touch capacitance detection according to the present invention.
Fig. 5 is a schematic diagram illustrating distribution of touch display areas and fingerprint detection and touch display areas in a display screen.
Fig. 6 is another schematic diagram illustrating distribution of touch display areas and fingerprint detection and touch display areas in a display screen.
FIGS. 7A and 7B are block diagrams illustrating a fingerprint recognition device with a capacitive elimination mask line according to the present invention.
FIGS. 8A and 8B are block diagrams illustrating a fingerprint recognition device with a capacitive elimination mask line according to the present invention.
Fig. 9 is a schematic diagram illustrating the distribution of touch display areas and fingerprint detection and touch display areas in a display screen.
FIG. 10 is a block diagram illustrating a fingerprint identification device with a capacitive elimination mask line according to the present invention.
FIG. 11A is a schematic diagram illustrating the mutual capacitance of adjacent data lines.
Fig. 11B is a diagram illustrating self-capacitance of the data line.
FIG. 11C is a cross-sectional view illustrating an anti-capacitive masking line structure of a fingerprint identification device with an anti-capacitive masking line according to an embodiment of the invention.
FIG. 11D is a cross-sectional view illustrating an anti-capacitive masking line structure of a fingerprint identification device having an anti-capacitive masking line according to another embodiment of the present invention.
FIG. 11E is a cross-sectional view illustrating an anti-capacitive masking line structure of a fingerprint identification device having an anti-capacitive masking line according to another embodiment of the present invention.
Description of the symbols:
a fingerprint recognition device 10;
a substrate 100;
the fingerprint electrode layer 110 and the fingerprint sensing electrode 112;
first insulating layer 150A second insulating layer 150B;
a third insulating layer 150C;
a first capacitive elimination shielding line 140A and a second capacitive elimination shielding line 140B;
drive circuits a1, a2, A3;
a virtual data line 132;
data lines 11L1, 21L 1-21L 3, 22L 1-22L 3, 23L 1-23L 3, 1mL1, 2mL 1-2 mL3 and 2nL 1-2 nL 3;
gate lines 1Y1 to 1Y3 to 8Y1 to 8Y 3;
a first capacitor C1 and a second capacitor C2;
fingerprint sensing capacitance Cfse;
capacitances Cfdl, Cedl 1, Cedl 2.. Cedln, Cfse 1-Cfsen, Cfsem, Cdl;
a self-capacitance Cself;
a fingerprint sensing electrode SE;
selecting fingerprint sensing electrodes Sem, SEm1 and SEm 2;
unselected fingerprint sensing electrodes SE 1-Sen;
widths W1, W2, W3;
a fingerprint/touch detection circuit 200;
capacitive driving signal source 230 first amplifier 220A;
a second amplifier 220B, a third amplifier 220C;
a first switch SW1 and a second switch SW 2;
a fingerprint sensing signal VS capacitor eliminates a shielding signal VE;
a display control circuit 300;
a display screen 400;
a touch display area 400A, a fingerprint detection and touch display area 400B;
a fingerprint sensing electrode a11.. a 1. n.. am1.. am n;
fingerprint detection and touch display units A, B and C;
touch-control sensing electrode D, E, F, G, H, I, J, K, L.
Detailed Description
The present invention is further described with reference to the following drawings and specific examples so that those skilled in the art can better understand the present invention and can practice the present invention, but the examples are not intended to limit the present invention.
Referring to fig. 1A to 1C, schematic diagrams of the fingerprint identification device with the capacitance-eliminating masking line according to the present invention are respectively illustrated. Referring to fig. 1A, a first capacitive elimination shielding line 140A and a second capacitive elimination shielding line 140B are respectively disposed at adjacent positions of the data line 130, for example, the first capacitive elimination shielding line 140A and the second capacitive elimination shielding line 140B are respectively disposed above and below the data line 130. The above-mentioned upper and lower portions can be, for example, directions that are familiar to the operator when the fingerprint recognition device is used; however, it should be understood that according to the present invention, the first and second capacitive shielding lines 140A and 140B may be disposed at left and right sides of the data line 130 as long as the data line 130 is sandwiched therebetween. In addition, if the noise of the data line 130 mainly comes from one side (e.g., the lower side), the invention can also have only a single capacitive reduction shielding line, as shown in fig. 4, for example, and the efficacy of the invention can also be achieved, and the scope of the invention is not limited by the illustrated embodiment. As shown in fig. 1A, the first capacitive shielding line 140A has a width W1, the second capacitive shielding line 140B has a width W2, and the data line 130 has a width W3. Although the noise interference from the top and bottom can be shielded by the capacitive shielding lines in such a manner that the data lines 130 are sandwiched in the vertical direction, if the first and second capacitive shielding lines 140A and 140B are not appropriately biased, the crosstalk interference problem is serious. In other words, if one end of the first capacitive elimination mask line 140A, one end of the second capacitive elimination mask line 140B, and one end of the data line 130 are all grounded, and the other end of the data line 130 outputs the fingerprint sensing signal through the driving circuit (e.g., an amplifier) a1, the first capacitor C1 is generated between the first capacitive elimination mask line 140A and the data line 130, and the second capacitor C2 is generated between the second capacitive elimination mask line 140B and the data line 130. At this time, the first capacitor C1 and the second capacitor C2 cause the crosstalk of the fingerprint sensing signals, which affects the accuracy of fingerprint detection.
Referring to fig. 1B, if the fingerprint sensing signal of the data line 130 (the capacitance detection result from the selected fingerprint sensing electrode) is amplified into a capacitance canceling shielding signal by a driving circuit (e.g., an amplifier) a2 with a gain greater than or equal to zero and then applied to the first and second canceling shielding lines 140A and 140B, the first capacitance C1 generated between the first canceling shielding line 140A and the data line 130 is zero, and the second capacitance C2 generated between the second canceling shielding line 140B and the data line 130 is also zero, so that the first canceling shielding line 140A and the second canceling shielding line 140B do not cause crosstalk of the output fingerprint sensing signal and do not affect the detection accuracy. The first capacitive-elimination shielding line 140A and the second capacitive-elimination shielding line 140B can also provide the shielding effect of the data line 130, i.e. the fingerprint identification device with the capacitive-elimination shielding lines of the present invention can correctly detect the fingerprint sensing capacitance Cfs (the detection result generated by pressing the finger on the selected fingerprint sensing electrode and output through the data line 130). In the above description, the gain of the driver circuit a2 is greater than or equal to zero; and when detecting the fingerprint, the gain of the driving circuit a2 is greater than zero (e.g. 1) to amplify the fingerprint sensing signal in phase.
Referring to fig. 1C, if the fingerprint sensing signal of the data line 130 is amplified into a capacitance-canceling shielding signal by a driving circuit (e.g., an amplifier) a2 with a gain greater than or equal to zero and then applied to the first capacitance-canceling shielding line 140A, and is amplified into a capacitance-canceling shielding signal by another driving circuit (e.g., an amplifier) A3 with a gain greater than or equal to zero and then applied to the second capacitance-canceling shielding line 140B, the first capacitance C1 generated between the first capacitance-canceling shielding line 140A and the data line 130 is also zero, and the second capacitance C2 generated between the second capacitance-canceling shielding line 140B and the data line 130 is also zero, so that the fingerprint sensing device with capacitance-canceling shielding lines of the present invention does not cause crosstalk of the output fingerprint sensing signal and does not affect the detection accuracy, i.e., the fingerprint sensing capacitance Cfs can be correctly detected by the fingerprint sensing device with capacitance-canceling shielding lines of the present invention. Similarly, in the above description, the gains of the driver circuits a2 and A3 are equal to or greater than zero; and when detecting the fingerprint, the gains of the driving circuits a2 and A3 are greater than zero (e.g., 1) to amplify the fingerprint sensing signal in phase.
Referring to fig. 2, an effect of data lines on touch capacitance detection in a conventional fingerprint recognition device is illustrated. As shown in the figure, since the data line 130 generally has a very long extension length (relative to the fingerprint sensing electrode SE), for example, if the length of the data line 130 is 20,000um, even if its width is only 5um (smaller than the width of the fingerprint sensing electrode SE), the area is still as high as 100,000um2. Area 50x50=2,500um with respect to the fingerprint sensing electrode SE2And 40 times more. In other words, if the data line 130 is adjacent to the fingerprint sensing electrode SE, the capacitance Cfdl between the finger of the user and the data line 130 is 40 times the fingerprint sensing capacitance Cfse, which affects the detection accuracy.
Referring to fig. 3, the influence of data lines on the detection of touch capacitance in the conventional fingerprint recognition device is illustrated. As shown in this figure, in addition to the effect of the data line 130, there are capacitances Cfse 1-Cfsen between the unselected fingerprint sensing electrodes SE1-SEn near the data line 130 and the finger, respectively; there are also capacitances Cfsed 11-Cfsed 1n between the unselected fingerprint sensing electrodes SE1-SEn and the data line 130. these capacitances Cfsed 11-Cfsed 1n also affect the sensing accuracy of the fingerprint sensing capacitance Cfse for the selected fingerprint sensing electrode SEm. Furthermore, the number of non-selected fingerprint sensing electrodes SE1-SEn is much larger than the number of selected fingerprint sensing electrodes SEm, resulting in a more serious disturbance of the fingerprint sensing capacitance Cfse.
Referring to fig. 4, a schematic diagram illustrating an improvement of the influence of data lines on the touch capacitance detection in a fingerprint recognition device by using a capacitive shielding line according to the present invention is shown. Referring to the figure, and referring to fig. 1B and fig. 1C in combination, if at least one capacitive cancellation masking line (e.g., the illustrated first capacitive cancellation masking line 140A) is set up for each data line 130, and the fingerprint sensing signal of the data line 130 is amplified by a driving circuit (e.g., an amplifier) a1 with a gain greater than or equal to zero to generate a capacitive cancellation masking signal in phase with the fingerprint sensing signal. The capacitive blanking signal is applied to the first blanking line 140A, so that there is no capacitance (no potential difference) between the data line 130 and the first blanking line 140A. Similarly, the capacitive blanking signal can be applied to the unselected fingerprint sensing electrodes SE1-SEn, so that there is no capacitance between the unselected fingerprint sensing electrodes SE1-SEn and the data line 130, and thus the fingerprint sensing capacitance Cfse for the selected fingerprint sensing electrode SEm can be more accurately detected. In the embodiment of FIG. 4, although only one erase mask line (i.e., the first erase mask line 140A) is shown, a capacitive erase mask signal is also applied to the unselected fingerprint sensing electrodes SE 1-SEn; however, according to another embodiment of the present invention, in a manner similar to that shown in fig. 1B and fig. 1C, a first capacitive elimination shielding line 140A and a second capacitive elimination shielding line 140B are respectively disposed above and below the data line 130, and capacitive elimination shielding signals are respectively applied to the first capacitive elimination shielding line 140A and the second capacitive elimination shielding line 140B to reduce interference. In the above description, the gain of the driver circuit a1 is greater than or equal to zero; and when detecting the fingerprint, the gain of the driving circuit a1 is greater than zero (e.g. 1) to amplify the fingerprint sensing signal in phase to generate the capacitance-eliminating mask signal.
Referring to fig. 9, a schematic diagram illustrating a touch display area 400A and a fingerprint detection and touch display area 400B in a display screen 400 is shown. In a display screen 400 of a portable electronic product, a touch display area 400A is usually provided for a user to perform touch input and display information; and a fingerprint detection area for user identification. Since the resolution of the fingerprint detection is greater than the touch resolution, according to an embodiment of the present invention, the plurality of fingerprint sensing electrodes a11.. 1n.. am1.. Amn may form a fingerprint detection and touch display unit a, and the plurality of fingerprint detection and touch display units a, B, C may form a fingerprint detection and touch display area 400B. The display screen 400 includes a touch display area 400A (including a plurality of touch sensing electrodes D, e.. K, L) and a fingerprint detection and touch display area 400B. In the above description, the area of each touch sensing electrode is more than 50 times, for example, 50-100 times, or 1000 times the area of the fingerprint sensing electrode. Furthermore, since the density of the fingerprint sensing electrodes a11.. a 1.. am n is much greater than that of the touch sensing electrodes D, e.. K, L, the density of the data lines in the fingerprint detection and touch display area 400B is higher. In order to make the transmittance of the touch display area 400A and the transmittance of the fingerprint detection and touch display area 400B including the plurality of fingerprint sensing electrodes the same or similar, a plurality of dummy data lines (dummy data lines) 132 may be disposed in the touch display area 400A. The arrangement density of the dummy data lines 132 may be similar to that of the data lines 130, for example, and no control circuit is required to be connected, so that the touch display area 400A and the fingerprint detection and touch display area 400B have the same or similar transmittance, thereby increasing the visual comfort of the user during operation.
Referring to fig. 5, the touch area of the display screen 400 can be divided into an upper touch display area 400A and a lower fingerprint detection and touch display area 400B. Referring to fig. 9, the fingerprint detection and touch display unit a in the fingerprint detection and touch display area 400B is composed of a plurality of fingerprint sensing electrodes a11.. a 1. n.. am1.. Amn. Referring to fig. 1B and 1C, a first capacitive elimination shielding line 140A and a second capacitive elimination shielding line 140B are respectively disposed above and below the data line 130 of the fingerprint sensing electrode, and capacitive elimination shielding signals having the same phase as the fingerprint sensing signal are respectively applied to the first capacitive elimination shielding line 140A and the second capacitive elimination shielding line 140B to reduce interference. Therefore, the fingerprint detection and touch display area 400B of the display screen 400 of fig. 5 has a more accurate detection result and can eliminate the crosstalk of data lines.
Referring to fig. 6, the touch area of the display screen 400 also has a touch display area 400A and a fingerprint detection and touch display area 400B. However, compared to the embodiment of fig. 5, the area of the fingerprint detection and touch display area 400B is smaller. Similarly, referring to fig. 9, the fingerprint detection and touch display unit a in the fingerprint detection and touch display area 400B is composed of a plurality of fingerprint sensing electrodes a11.. a1n.. am1.. am n. Referring to fig. 1B and 1C, a first capacitive elimination shielding line 140A and a second capacitive elimination shielding line 140B are respectively disposed above and below the data line 130 of the fingerprint sensing electrode, and capacitive elimination shielding signals having the same phase as the fingerprint sensing signal are respectively applied to the first capacitive elimination shielding line 140A and the second capacitive elimination shielding line 140B to reduce interference. Therefore, the fingerprint detection and touch display area 400B of the display screen 400 of fig. 6 also has a more accurate detection result and can eliminate the crosstalk of the data lines.
Referring to FIG. 7A, a block diagram of a fingerprint identification device with a capacitive elimination mask line according to the present invention is shown. The fingerprint identification device 10 is configured in a self-capacitance structure and has a fingerprint/touch detection circuit 200 and a display control circuit 300, wherein the fingerprint/touch detection circuit 200 has a first power source 210 and a first ground 212; the display control circuit 300 has a second power source 310 and a second ground 312, wherein the first ground 212 is different from the second ground 312. In addition, the fingerprint/touch detection circuit 200 further has a capacitive driving signal source 230, a first amplifier 220A and a second amplifier 220B. The fingerprint recognition device further has a first switch SW1 and a second switch SW 2. Referring to fig. 7A, in the fingerprint detection stage (or the touch detection stage, see fig. 9 in cooperation, a plurality of fingerprint sensing electrodes a11.. a1n.. am1.. Amn may form a fingerprint detection and touch display unit a for touch detection), the first switch SW1 and the second switch SW2 are turned on (closed), so that the capacitive excitation signal of the capacitive excitation signal source 230 may be transmitted to the selected sensing electrode SEm1 through the first switch SW1, and the capacitive induction signal (response to the fingerprint detection result) on the sensing electrode SEm1 may be transmitted to the first amplifier 220A through the second switch SW2, and processed into a fingerprint induction signal VS through the first amplifier 220A; the fingerprint sensing signal VS is transmitted through a corresponding data line (not shown in the figure, see fig. 4). Furthermore, the fingerprint sensing signal VS is also passed through a second amplifier 220B (a driving circuit with a gain greater than or equal to zero) to form a capacitive cancellation mask signal VE in phase with the fingerprint sensing signal VS. Referring to fig. 1B and 1C, a first capacitive elimination shielding line 140A and a second capacitive elimination shielding line 140B are respectively disposed above and below the data line 130 of the fingerprint sensing electrode, and the fingerprint/touch detection circuit 200 applies a capacitive elimination shielding signal VE to the first capacitive elimination shielding line 140A and the second capacitive elimination shielding line 140B, respectively, to reduce interference. Therefore, the fingerprint identification device with the elimination of the shielded lines in FIG. 7A can have more accurate detection results and can eliminate the crosstalk of the data lines. In the above description, the gain of the second amplifier (drive circuit) 220B is greater than or equal to zero; during fingerprint detection, the gain of the second amplifier 220B is greater than zero (e.g., 1) to amplify the fingerprint sensing signal VS in phase to generate the capacitive cancellation masking signal VE. In addition, in the fingerprint detection stage or the touch detection stage, the fingerprint/touch detection circuit 200 and the display control circuit 300 are connected by only a single physical wire, the first ground 212 is a ground different from the second ground 312, and there is no common current loop between the first power 210 and the second power 310, so as to further improve the fingerprint detection or touch detection accuracy.
Referring to FIG. 7B, a block diagram of a fingerprint identification device with a capacitive elimination mask line according to the present invention is shown, wherein the fingerprint identification device is in a non-fingerprint detection phase (e.g., a display phase or a signal communication phase). At this stage, the first switch SW1 and the second switch SW2 are turned off (opened), so that the capacitive driving signal of the capacitive driving signal source 230 is not transmitted to the selected sensing electrode SEm 1. Furthermore, at this stage, the fingerprint/touch detection circuit 200 and the display control circuit 300 can be electrically connected through two wires, so that the display control circuit 300 can charge the fingerprint/touch detection circuit 200, or the display control circuit 300 and the fingerprint/touch detection circuit 200 can communicate with each other.
Referring to FIG. 8A, a block diagram of a fingerprint identification device with a capacitive elimination mask line according to the present invention is shown. The fingerprint identification device 10 is used in a mutual capacitance architecture and has a fingerprint/touch detection circuit 200 and a display control circuit 300, wherein the fingerprint/touch detection circuit 200 has a first power source 210 and a first ground 212; the display control circuit 300 has a second power source 310 and a second ground 312, wherein the first ground 212 is different from the second ground 312. In addition, the fingerprint/touch detection circuit 200 further has a capacitive driving signal source 230, a first amplifier 220A and a second amplifier 220B. The fingerprint recognition device further has a first switch SW1 and a second switch SW 2. Referring to fig. 8A, in the fingerprint detection phase or the touch detection phase, the first switch SW1 and the second switch SW2 are turned on (closed), so that the capacitive excitation signal of the capacitive excitation signal source 230 can be transmitted to the selected sensor electrode SEm1 through the first switch SW 1. Furthermore, the fingerprint/touch detection circuit 200 further receives a capacitive sensing signal (reflecting the fingerprint detection result) from another selected sensing electrode SEm2 through the second switch SW2, and processes the capacitive sensing signal into a fingerprint sensing signal VS through the first amplifier 220A. Furthermore, the fingerprint sensing signal VS is also passed through a second amplifier 220B (a driving circuit with a gain greater than or equal to zero) to form a capacitive cancellation mask signal VE in phase with the fingerprint sensing signal. Referring to fig. 1B and 1C, a first capacitive elimination shielding line 140A and a second capacitive elimination shielding line 140B are respectively disposed above and below the data line 130 of the fingerprint sensing electrode, and the fingerprint/touch detection circuit 200 applies a capacitive elimination shielding signal VE to the first capacitive elimination shielding line 140A and the second capacitive elimination shielding line 140B, respectively, to reduce interference. Therefore, the fingerprint identification device with the elimination of the shielded lines shown in FIG. 8A can have more accurate detection results and can eliminate the crosstalk of the data lines. In the above description, the gain of the second amplifier (drive circuit) 220B is greater than or equal to zero; and during fingerprint detection, the gain of the second amplifier 220B is greater than zero (e.g. 1) to amplify the fingerprint sensing signal in phase, so as to generate the capacitive cancellation mask signal VE. In addition, in the fingerprint detection stage or the touch detection stage, the fingerprint/touch detection circuit 200 and the display control circuit 300 are connected by only a single physical wire, and the first ground 212 is a ground different from the second ground 312, so that there is no common current loop between the first power 210 and the second power 310, thereby further improving the fingerprint detection or touch detection accuracy.
Referring to FIG. 8B, a block diagram of a fingerprint identification device with a capacitive elimination mask line according to the present invention is shown. The fingerprint identification device 10 is used in a self-capacitance/mutual-capacitance architecture and has a fingerprint/touch detection circuit 200 and a display control circuit 300, wherein the fingerprint/touch detection circuit 200 has a first power source 210 and a first ground 212; the display control circuit 300 has a second power source 310 and a second ground 312, wherein the first ground 212 is different from the second ground 312. In addition, the fingerprint/touch detection circuit 200 further has a capacitive driving signal source 230, a first amplifier 220A and a second amplifier 220B. The fingerprint recognition device further has a first switch SW1 and a second switch SW 2. Referring to fig. 8B, in the fingerprint detection phase, the first switch SW1 and the second switch SW2 are turned on (closed), so that the capacitive driving signal of the capacitive driving signal source 230 can be transmitted to the selected sensing electrode SEm1 and the other selected sensing electrode SEm2 through the first switch SW1 (the capacitive driving signal is amplified by the third amplifier 220C and then applied to the other selected sensing electrode SEm 2). Furthermore, the fingerprint/touch detection circuit 200 further receives a capacitive sensing signal (reflecting the fingerprint detection result) from another selected sensing electrode SEm2 through the second switch SW2, and processes the capacitive sensing signal into a fingerprint sensing signal VS through the first amplifier 220A. Furthermore, the fingerprint sensing signal VS is also passed through a second amplifier 220B (a driving circuit with a gain greater than or equal to zero) to form a capacitive cancellation mask signal VE in phase with the fingerprint sensing signal. Referring to fig. 1B and 1C, a first capacitive elimination shielding line 140A and a second capacitive elimination shielding line 140B are respectively disposed above and below the data line 130 of the fingerprint sensing electrode, and the fingerprint/touch detection circuit 200 applies a capacitive elimination shielding signal VE to the first capacitive elimination shielding line 140A and the second capacitive elimination shielding line 140B, respectively, to reduce interference. Therefore, the fingerprint identification device with the elimination of the shielded lines shown in FIG. 8B can achieve more accurate detection results and eliminate the crosstalk of the data lines. In the above description, the gain of the second amplifier (drive circuit) 220B is greater than or equal to zero; and during fingerprint detection, the gain of the second amplifier 220B is greater than zero (e.g. 1) to amplify the fingerprint sensing signal in phase, so as to generate the capacitive cancellation mask signal VE. In addition, in the fingerprint detection stage or the touch detection stage, the fingerprint/touch detection circuit 200 and the display control circuit 300 are connected by only a single physical wire, and the first ground 212 is a ground different from the second ground 312, so that there is no common current loop between the first power 210 and the second power 310, thereby further improving the fingerprint detection or touch detection accuracy.
Referring to fig. 10, a circuit block diagram of a fingerprint identification device with a capacitive reduction masking line according to the present invention is shown, in which a plurality of fingerprint sensing electrodes and a plurality of corresponding transistor switch sets are shown, that is, the plurality of transistor switch sets and the plurality of fingerprint sensing electrodes are in one-to-one correspondence. Although fig. 10 shows three transistor switches for each fingerprint sensing electrode, it should be understood that according to the present invention, only one transistor switch may be provided for each fingerprint sensing electrode, so as to achieve the desired fingerprint sensing electrode selection function.
Referring to fig. 11A, to illustrate the mutual capacitance between the adjacent data lines, there is a mutual capacitance Cdl between the adjacent data lines 21L1 and 21L2, and there is a mutual capacitance Cdl between the adjacent data lines 21L2 and 21L 3. Because the distance between the data lines is very short, the mutual capacitance Cdl is far larger than the fingerprint sensing capacitance Cfs, and the fingerprint sensing accuracy is influenced. Referring to fig. 11B, for illustrating the self-capacitance of the data line, as shown in the figure, if the first capacitive reduction shielding line 140A or the adjacent conductor of the data line 130 is grounded and the first capacitive reduction shielding line 140A (or the adjacent conductor of the data line 130) is not properly biased, the maximum self-capacitance Cself also exists between the data line 130 and the ground.
FIG. 11C is a cross-sectional view of an embodiment of a fingerprint identification device with a mask line for eliminating capacitance. As shown in the figure, the fingerprint identification device may comprise a first capacitive shielding line 140A, a second capacitive shielding line, a third capacitive shielding line, a fourth capacitive shielding line, a fifth capacitive shielding line and a fourth capacitive shielding line from top to bottom,
A first insulating layer 150A, a data line 130 (21L 1, 21L2, 21L 3), a second insulating layer 150B, and a second anti-capacitive shielding line 140B. According to an embodiment of the invention, the widths of the first and second capacitive elimination shielding lines 140A and 140B may be greater than or equal to the width of the data line 130. In addition, since the data lines 130 (21L 1, 21L2, 21L 3) are generally fabricated by etching a metal layer through an etching process to form a space therebetween, there may be a gap between the data lines 21L1, 21L2, and 21L 3. If the first insulating layer 150A and the second insulating layer 150B are extremely thin (e.g., less than 1 um), the peripheries of the data line 21L1, the data line 21L2, and the data line 21L3 are almost shielded by the first and second canceling- capacitance shield lines 140A and 140B, and crosstalk, self capacitance, and mutual capacitance of the data lines can be canceled after the first and second canceling- capacitance shield lines 140A and 140B are appropriately biased.
Referring to FIG. 11D, a cross-sectional view of an anti-capacitive masking line structure of a fingerprint identification device with an anti-capacitive masking line according to another embodiment of the present invention is shown. As shown in the figure, the fingerprint identification device also includes a fingerprint electrode layer 110 (including a plurality of fingerprint sensing electrodes 112), a third insulating layer 150C, a first capacitive elimination shielding line 140A, a first insulating layer 150A, a data line 130 (21L 1, 21L2, 21L 3), a second insulating layer 150B, a second capacitive elimination shielding line 140B and a substrate 100 from top to bottom. However, in this embodiment, the widths of the first and second anti-capacitive shielding lines 140A and 140B are slightly larger than the width of the data line 130. Therefore, both ends of the first capacitive elimination mask line 140A can be slightly recessed to surround the data line 130 together with the second capacitive elimination mask line 140B. In this case, the thicknesses of the first insulating layer 150A and the second insulating layer 150B can be made thicker, which can further reduce the self capacitance and the mutual capacitance of the data line.
FIG. 11E is a cross-sectional view of an embodiment of a fingerprint identification device with a line of the present invention. This illustrated embodiment is similar to the embodiment of FIG. 11D, but the fingerprint electrode layer 110 is fabricated directly on top of the substrate 100. Similarly, the first and second capacitive shielding lines 140A and 140B are slightly larger than the width of the data line 130. Therefore, both ends of the first capacitive shielding line 140A may be slightly recessed to enclose the data line 130 together with the second capacitive shielding line 140B. In this case, the thicknesses of the first insulating layer 150A and the second insulating layer 150B can be made thicker, which can further reduce the self capacitance and the mutual capacitance of the data line. In fig. 11D and 11E, the substrate 100 may be a cover glass of a display screen, a silicon substrate of an integrated circuit, or a polymer film. In the above-described embodiments, the data lines are metal conductive lines or transparent conductors, such as Indium Tin Oxide (ITO); the plurality of fingerprint sensing electrodes are made of transparent conductive materials.
In summary, the fingerprint identification device with the capacitive elimination shielding lines provided by the invention can reduce interference and have more accurate detection result by applying the capacitive elimination shielding signals to the first capacitive elimination shielding line and the second capacitive elimination shielding line respectively and clamping the data line by the first capacitive elimination shielding line and the second capacitive elimination shielding line.
The above-mentioned embodiments are merely preferred embodiments for fully illustrating the present invention, and the scope of the present invention is not limited thereto. The equivalent substitution or change made by the technical personnel in the technical field on the basis of the invention is all within the protection scope of the invention. The protection scope of the invention is subject to the claims.
Claims (14)
1. A fingerprint recognition device, comprising:
a substrate;
a fingerprint electrode layer including a plurality of fingerprint sensing electrodes;
a transistor switch layer, comprising:
a plurality of transistor switch groups, wherein the plurality of transistor switch groups correspond to the plurality of fingerprint sensing electrodes in a one-to-one manner;
the data lines are respectively corresponding to a first capacitance elimination shielding line and a second capacitance elimination shielding line, so that the first capacitance elimination shielding line and the second capacitance elimination shielding line are clamped with one corresponding data line; the first capacitance eliminating shielding line is positioned between the corresponding data line and a finger to be detected so as to eliminate the influence of the finger to be detected on the corresponding data line;
the fingerprint detection circuit comprises a capacitance excitation signal source and a driving circuit, wherein the gain of the driving circuit is greater than or equal to zero;
the fingerprint detection circuit transmits a capacitance excitation signal to a selected fingerprint sensing electrode through one of the transistor switch sets, inputs a fingerprint sensing signal from the selected fingerprint sensing electrode through the corresponding data line, processes the fingerprint sensing signal through the driving circuit to output a capacitance elimination shielding signal which is in the same phase with the fingerprint sensing signal, and transmits the capacitance elimination shielding signal to the first capacitance elimination shielding line and the second capacitance elimination shielding line corresponding to the corresponding data line for fingerprint detection operation.
2. The apparatus of claim 1, wherein the second capacitive-elimination mask is disposed on a side of the corresponding data line opposite to the finger to be tested to eliminate an influence of noise from the side on the corresponding data line.
3. The fingerprint recognition device according to claim 1, wherein the line width of the first descum mask line and the second descum mask line is not smaller than the corresponding line width of the corresponding data line.
4. The fingerprint recognition device of claim 1, wherein each of the transistor switch sets comprises at least one thin film transistor.
5. The fingerprint identification device of claim 1, wherein the fingerprint detection circuit further applies the capacitive cancellation masking signal to the fingerprint sensing electrodes surrounding the corresponding data lines during a fingerprint detection operation to prevent other sensing signals and noise from being conducted to the corresponding data lines via the surrounding fingerprint sensing electrodes.
6. The fingerprint identification device according to claim 1, wherein the fingerprint detection circuit is powered by a first power source, the fingerprint identification device further comprises a display screen powered by a second power source, and the plurality of fingerprint sensing electrodes are located in a fingerprint detection and touch display area of the display screen.
7. The fingerprint recognition device according to claim 6, wherein said plurality of fingerprint sensing electrodes are combined as a touch electrode for touch detection.
8. The fingerprint identification device according to claim 7, wherein there is no common current loop between the first power source and the second power source during fingerprint detection operation or touch detection operation.
9. The fingerprint recognition device according to claim 7, wherein a plurality of touch electrodes are disposed in a touch display area of the display screen for touch detection, and an area of each touch electrode is more than 50 times an area of the fingerprint sensing electrode.
10. The fingerprint identification device according to claim 9, further comprising a plurality of dummy data lines disposed in the touch display area, such that the touch display area has the same or similar transmittance as the fingerprint detection and touch display area including the plurality of fingerprint sensing electrodes.
11. The fingerprint recognition device according to claim 1, wherein the substrate is a cover glass of a display screen, a silicon substrate of an integrated circuit, or a polymer film.
12. The fingerprint recognition device of claim 1, wherein the data lines are metal conductive lines or transparent conductors.
13. The fingerprint identification device of claim 1, wherein the plurality of fingerprint sensing electrodes are made of transparent conductive material.
14. The fingerprint recognition device of claim 12, wherein the transparent conductor is indium tin oxide.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010830997.9A CN114155563A (en) | 2020-08-18 | 2020-08-18 | Fingerprint identification device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010830997.9A CN114155563A (en) | 2020-08-18 | 2020-08-18 | Fingerprint identification device |
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| Publication Number | Publication Date |
|---|---|
| CN114155563A true CN114155563A (en) | 2022-03-08 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010830997.9A Pending CN114155563A (en) | 2020-08-18 | 2020-08-18 | Fingerprint identification device |
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| Country | Link |
|---|---|
| CN (1) | CN114155563A (en) |
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2020
- 2020-08-18 CN CN202010830997.9A patent/CN114155563A/en active Pending
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