TWI798693B - Capacitive fingerprint sensing device, touch display panel and information processing device using it - Google Patents

Abstract

A capacitive fingerprint sensing device, which has: a capacitive sensor array, located in a fingerprint sensing area, which performs a fingerprint scanning operation on the fingerprint sensing area in a working mode, and in a sleep mode Stopping the fingerprint scanning operation in a first stage, and performing a touch detection operation on a partial area of the fingerprint sensing area in a second stage of the sleep mode to generate a second wake-up signal; at least one capacitance sensing circuit, Distributed on at least one periphery of the fingerprint sensing area, each of the capacitance sensing circuits has a charge-to-voltage circuit and a comparator, wherein, in the first stage, the charge-to-voltage circuit generates a voltage signal, and the comparator compares the voltage signal according to a reference voltage to generate a first wake-up signal to enable the capacitive sensor array to enter the second stage; and a control unit for receiving the first wake-up signal The second wake-up signal drives the capacitive sensor array into the working mode.

Description

Capacitive fingerprint sensing device, touch display panel and information processing device using it

The present invention relates to fingerprint verification, in particular to a capacitive fingerprint sensing device with power saving function.

With the popularity and vigorous development of mobile devices, touch display panels have become an indispensable component, and fingerprint authentication has also become an essential function.

A general mobile device will be provided with a capacitive fingerprint unlocking key at the bottom of the screen to facilitate the user to perform fingerprint unlocking operations. Since the capacitive fingerprint unlocking key only performs fingerprint scanning during the period when fingerprint verification is required, such as when powering on or conducting online financial transactions, the general capacitive fingerprint unlocking key will be in a dormant state during other periods to save power consumption.

In addition, in order for the capacitive fingerprint unlocking key to start a fingerprint verification process, a touch sensing mechanism must be set inside it to start the fingerprint verification process when a finger pressing operation is detected. The general method is to judge whether there is a finger pressing operation by detecting a plurality of sensing electrodes in a central area of the capacitive fingerprint unlocking key, and if so, enter a fingerprint scanning procedure.

However, because the detection circuit matched with each sensing electrode in a capacitive fingerprint unlocking key is generally composed of a charge-to-voltage circuit and an analog-to-digital circuit, and the analog-to-digital circuit consumes a considerable amount of power, therefore, existing The energy-saving performance of the capacitive fingerprint unlocking key still has room for improvement.

In order to solve the above problems, there is an urgent need in the art for a novel capacitive fingerprint sensing device.

An object of the present invention is to disclose a capacitive fingerprint sensing device, which can provide a first-stage wake-up function with low power consumption by arranging a capacitive sensing circuit around a fingerprint sensing area.

Another object of the present invention is to disclose a capacitive fingerprint sensing device, which can detect a plurality of sensing electrodes in a central area of the fingerprint sensing area when the aforementioned capacitive sensing circuit detects a touch event. A second-stage wake-up function is provided to execute a fingerprint scanning procedure while saving power consumption and avoiding misjudgment.

To achieve the aforementioned purpose, a capacitive fingerprint sensing device is proposed, which has:

a capacitive sensor array located in a fingerprint sensing area, which performs a fingerprint scanning operation on the fingerprint sensing area in an active mode, stops the fingerprint scanning operation in a first stage of a sleep mode, and performing a touch detection operation on a partial area of the fingerprint sensing area in a second stage of the sleep mode to generate a second wake-up signal;

At least one capacitance sensing circuit is distributed in at least one periphery of the fingerprint sensing area, each of the capacitance sensing circuits has a charge-to-voltage circuit and a comparator, wherein, in the first stage, the charge-to-voltage circuit is generating a voltage signal according to a touch operation, and the comparator compares the voltage signal according to a reference voltage to generate a first wake-up signal to enable the capacitive sensor array to enter the second stage; and

A control unit is used for driving the capacitive sensor array into the working mode when receiving the second wake-up signal.

In one embodiment, the capacitive sensor array has a plurality of fingerprint detection circuits, each of the fingerprint detection circuits has a charge-to-voltage circuit to generate an output voltage according to a partial fingerprint, and analogously The digital converter generates a digital output value according to the output voltage.

In one embodiment, the fingerprint sensing area is a square area.

In one embodiment, the capacitive fingerprint sensing device has a substrate for carrying the capacitive sensor array, the at least one capacitive sensing circuit and the control unit.

In one embodiment, the number of the fingerprint detection circuits is greater than the number of the capacitive sensing circuits.

To achieve the aforementioned purpose, the present invention further proposes a touch display panel, which has a touch screen and a capacitive fingerprint sensing device, and the capacitive fingerprint sensing device has:

a capacitive sensor array located in a fingerprint sensing area, which performs a fingerprint scanning operation on the fingerprint sensing area in an active mode, stops the fingerprint scanning operation in a first stage of a sleep mode, and performing a touch detection operation on a partial area of the fingerprint sensing area in a second stage of the sleep mode to generate a second wake-up signal;

At least one capacitance sensing circuit is distributed in at least one periphery of the fingerprint sensing area, each of the capacitance sensing circuits has a charge-to-voltage circuit and a comparator, wherein, in the first stage, the charge-to-voltage circuit is generating a voltage signal according to a touch operation, and the comparator compares the voltage signal according to a reference voltage to generate a first wake-up signal to enable the capacitive sensor array to enter the second stage; and

A control unit is used for driving the capacitive sensor array into the working mode when receiving the second wake-up signal.

In one embodiment, the capacitive sensor array has a plurality of fingerprint detection circuits, each of the fingerprint detection circuits has a charge-to-voltage circuit to generate an output voltage according to a partial fingerprint, and analogously The digital converter generates a digital output value according to the output voltage.

In one embodiment, the fingerprint sensing area is a square or circular area.

In one embodiment, the capacitive fingerprint sensing device has a substrate for carrying the capacitive sensor array, the at least one capacitive sensing circuit and the control unit.

In one embodiment, the number of the fingerprint detection circuits is greater than the number of the capacitive sensing circuits.

In a possible embodiment, the display of the touch screen may be a liquid crystal display, a light emitting diode display, a mini light emitting diode (Mini-LED) display, a micro light emitting diode (Micro-LED) display, a quantum dot Light Emitting Diode (Q-LED) displays or Organic Light Emitting Diode displays.

To achieve the aforementioned purpose, the present invention further proposes an information processing device, which has a central processing unit and the aforementioned touch display panel, wherein the central processing unit is used to communicate with the control unit.

In a possible embodiment, the information processing device may be a smart phone, a portable computer, a vehicle computer or an access control device.

In order to enable your review committee members to further understand the structure, features and purpose of the present invention, drawings and detailed descriptions of preferred specific embodiments are hereby attached.

Please refer to FIG. 1 , which is a schematic diagram of an embodiment of a capacitive fingerprint sensing device of the present invention. As shown in FIG. 1 , a capacitive fingerprint sensing device 100 has a capacitive sensor array 110 , at least one capacitive sensing circuit 120 and a control unit 130 .

the capacitive sensor array 110 is located in a fingerprint sensing area, performs a fingerprint scanning operation on the fingerprint sensing area in an active mode, stops the fingerprint scanning operation in a first stage of a sleep mode, and In a second stage of the sleep mode, a touch detection operation is performed on a partial area of the fingerprint sensing area to generate a second wake-up signal V _WK2 .

At least one capacitance sensing circuit 120 is distributed on at least one periphery of the fingerprint sensing area, and each capacitance sensing circuit 120 has a detection circuit 121 and a sensing electrode 122 . Please refer to FIG. 2 , which shows a circuit diagram of an embodiment of the detection circuit 121 in FIG. 1 . As shown in FIG. 2 , the detection circuit 121 has a charge-to-voltage circuit 121a and a comparator 121b, wherein, in the first stage, the charge-to-voltage circuit 121a generates a voltage signal V _S according to a touch operation, and The comparator 121b compares the voltage signal V _S with a reference voltage V _REF to generate a first wake-up signal V _WK1 to enable the capacitive sensor array 110 to enter the second stage.

The control unit 130, after receiving the first wake-up signal V _WK1 , outputs a first enable signal EN1 to drive the capacitive sensor array 110 into the second stage, and it receives the second wake-up signal V _WK2 will output a second enable signal EN2 to drive the capacitive sensor array 110 into the working mode.

In addition, the capacitive sensor array 110 has a plurality of fingerprint detection circuits. Please refer to FIG. 3 , which shows a circuit diagram of an embodiment of each fingerprint detection circuit of the capacitive sensor array 110 in FIG. 1 . As shown in FIG. 3 , a fingerprint detection circuit 111 has a sensing capacitor 111a, a charge-to-voltage circuit 111b and an analog-to-digital converter 111c, wherein the charge-to-voltage circuit 111b is based on a part of the pressing sensing capacitor 111a The fingerprint generates an output voltage V _FP , and the analog-to-digital converter 111c generates a digital output value D _OUT according to the output voltage V _FP under the control of a clock signal CLK.

In addition, the fingerprint sensing area can be a square, circular or other geometric area.

In addition, the capacitive fingerprint sensing device 100 has a substrate (not shown in the figure) to carry the capacitive sensor array 110 , the at least one capacitive sensing circuit 120 and the control unit 130 .

In addition, the number of the fingerprint detection circuits 111 is greater than the number of the capacitive sensing circuits 120 .

According to the above description, the capacitive fingerprint sensing device of the present invention can first use the capacitive sensing circuit 120 to provide a touch event prediction function under the condition of low power consumption, and then use the fingerprint detection circuit The touch sensing function provided by 111 confirms the touch event, so as to execute a fingerprint scanning process while saving power consumption and avoiding misjudgment.

According to the above description, the present invention further provides a touch display panel. Please refer to FIG. 4 , which shows a block diagram of an embodiment of the touch display panel of the present invention. As shown in FIG. 4, a touch display panel 200 has a touch screen 210 and a capacitive fingerprint sensing device 220, wherein the capacitive fingerprint sensing device 220 is realized by the capacitive fingerprint sensing device 100, and the touch The display of the control panel 210 can be a liquid crystal display, a light-emitting diode display, a mini light-emitting diode (Mini-LED) display, a micro-light-emitting diode (Micro-LED) display, a quantum dot light-emitting diode (Q-LED) ) displays or organic light emitting diode displays.

In addition, according to the above description, the present invention further discloses an information processing device. Please refer to FIG. 5 , which shows a block diagram of an embodiment of the information processing device of the present invention. As shown in FIG. 5, an information processing device 300 has a central processing unit 310 and a touch display panel 320, wherein the touch display panel 320 is realized by the touch display panel 200 (which has the control unit 130) , and the central processing unit 310 is used to communicate with the control unit 130 .

In addition, in a possible embodiment, the information processing device 300 can be a smart phone, a portable computer, a vehicle computer or an access control device.

With the design disclosed above, the present invention has the following advantages:

1. The capacitive fingerprint sensing device of the present invention can provide a first-stage wake-up function with low power consumption by disposing capacitive sensing circuits around a fingerprint sensing area.

2. The capacitive fingerprint sensing device of the present invention can provide a second-stage wake-up by detecting a plurality of sensing electrodes in a central area of the fingerprint sensing area when the aforementioned capacitive sensing circuit detects a touch event function, thereby executing a fingerprint scanning procedure while saving power consumption and avoiding misjudgment.

What is disclosed in this case is a preferred embodiment. For example, any partial changes or modifications derived from the technical ideas of this case and easily deduced by those who are familiar with the technology are within the scope of the patent right of this case.

To sum up, regardless of the purpose, means and efficacy of this case, it shows that it is very different from the conventional technology, and its first invention is practical, and it does meet the patent requirements of the invention. I implore your review committee to understand it clearly and grant a patent as soon as possible. Society is for the Most Prayer.

100: capacitive fingerprint sensing device 110: capacitive sensor array 111: Fingerprint detection circuit 111a: sensing capacitance 111b: Charge-to-voltage circuit 111c: Analog-to-Digital Converter 120: Capacitive sensing circuit 121: Detection circuit 121a: Charge-to-voltage circuit 121b: Comparator 122: Induction electrode 130: Control unit 200: touch display panel 210: touch screen 220: capacitive fingerprint sensing device 300: information processing device 310: central processing unit 320: touch display panel

FIG. 1 is a schematic diagram of an embodiment of a capacitive fingerprint sensing device of the present invention. FIG. 2 is a circuit diagram of an embodiment of the detection circuit of the capacitive fingerprint sensing device in FIG. 1 . FIG. 3 is a circuit diagram of an embodiment of each fingerprint detection circuit of the capacitive sensor array of the capacitive fingerprint sensing device in FIG. 1 . FIG. 4 shows a block diagram of an embodiment of the touch display panel of the present invention. FIG. 5 is a block diagram of an embodiment of an information processing device of the present invention.

100: capacitive fingerprint sensing device

110: capacitive sensor array

120: Capacitive sensing circuit

121: Detection circuit

122: Induction electrode

130: Control unit

Claims (11)

A capacitive fingerprint sensing device, which has: a capacitive sensor array, located in a fingerprint sensing area, which performs a fingerprint scanning operation on the fingerprint sensing area in a working mode, and in a sleep mode Stopping the fingerprint scanning operation in a first stage, and performing a touch detection operation on a partial area of the fingerprint sensing area in a second stage of the sleep mode to generate a second wake-up signal; at least one capacitance sensing circuit, Distributed on at least one periphery of the fingerprint sensing area, each of the capacitance sensing circuits has a charge-to-voltage circuit and a comparator, wherein, in the first stage, the charge-to-voltage circuit generates a voltage signal, and the comparator compares the voltage signal according to a reference voltage to generate a first wake-up signal to enable the capacitive sensor array to enter the second stage; and a control unit for receiving the first wake-up signal When a wake-up signal drives the capacitive sensor array into the working mode; wherein, the capacitive sensor array has a plurality of fingerprint detection circuits, and the number of the fingerprint detection circuits is greater than that of the capacitive sensing circuits number. The capacitive fingerprint sensing device as described in Item 1 of the scope of the patent application, wherein each of the fingerprint detection circuits has a charge-to-voltage circuit to generate an output voltage according to a partial fingerprint, and an analog-to-digital conversion The device generates a digital output value according to the output voltage. The capacitive fingerprint sensing device as described in item 1 of the scope of the patent application, wherein the fingerprint sensing area is a square or circular area. According to the capacitive fingerprint sensing device described in claim 1 of the patent application, it has a substrate for carrying the capacitive sensor array, the at least one capacitive sensing circuit and the control unit. A touch display panel, which has a touch screen and a capacitive fingerprint sensing device, the capacitive fingerprint sensing device has: a capacitive sensor array, located in a fingerprint sensing area, which is tied to a working In this mode, a fingerprint scanning operation is performed on the fingerprint sensing area, and the fingerprint scanning operation is stopped in one of the first stages of a dormant mode. and perform a touch detection operation on a partial area of the fingerprint sensing area in a second stage of the sleep mode to generate a second wake-up signal; at least one capacitive sensing circuit is distributed in the fingerprint sensing area At least one periphery, each of the capacitance sensing circuits has a charge-to-voltage circuit and a comparator, wherein, in the first stage, the charge-to-voltage circuit generates a voltage signal according to a touch operation, and the comparator is comparing the voltage signal with a reference voltage to generate a first wake-up signal to cause the capacitive sensor array to enter the second stage; and a control unit for driving the capacitive sensor array when receiving the second wake-up signal The sensor array enters the working mode; wherein, the capacitive sensor array has a plurality of fingerprint detection circuits, and the number of the fingerprint detection circuits is greater than the number of the capacitive sensing circuits. The touch display panel as described in item 5 of the scope of the patent application, wherein the capacitive sensor array has a plurality of fingerprint detection circuits, and each of the fingerprint detection circuits has a charge-to-voltage circuit according to A partial fingerprint generates an output voltage, and an analog-to-digital converter generates a digital output value according to the output voltage. The touch display panel as described in item 5 of the scope of the patent application, wherein the fingerprint sensing area is a square or circular area. The touch display panel as described in claim 5 of the patent application, wherein the capacitive fingerprint sensing device has a substrate for carrying the capacitive sensor array, the at least one capacitive sensing circuit and the control unit. The touch display panel as described in item 5 of the scope of patent application, wherein the display of the touch screen is composed of a liquid crystal display, a light-emitting diode display, a mini-light-emitting diode (Mini-LED) display, a micro light-emitting diode A display selected from the group consisting of Micro-LED (Micro-LED) display, Quantum Dot Light-Emitting Diode (Q-LED) display and Organic Light-Emitting Diode display. An information processing device has a central processing unit and a touch display panel as described in any one of items 5 to 9 of the scope of the patent application, wherein the central processing unit is used to communicate with the control unit. The information processing device described in item 10 of the scope of the patent application is a device selected from a group consisting of a smart phone, a portable computer, a vehicle-mounted computer and an access control device.

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