Voltage sensing fingerprint recognition device and fingerprint recognition method thereof

Abstract

The present invention provides a voltage sensing fingerprint recognition device and a fingerprint recognition method thereof. The voltage sensing fingerprint recognition device comprises: a sensor, which is arranged on a substrate, and the sensor comprises a plurality of sensing pads, the sensing pads are arranged in a plurality of rows, and each row has at least two sensing pads, and each sensing pad receives a trigger voltage; and a voltage capturer, which is electrically connected to each sensing pad; when the voltage capturer captures a sensing voltage value of the sensing pads in any row, the sensing pads in the row will stop receiving the trigger voltage. The present invention does not require an additional frame, so it can be applied to the display surface of electronic products.

Description

Technical Field

[0001] This invention relates to the field of fingerprint recognition, and more particularly to a voltage-sensing fingerprint recognition device and a fingerprint recognition method thereof. Background Technology

[0002] Currently, active capacitive fingerprint recognition devices require an additional frame (such as a metal frame) to provide voltage to the sensing pad. When a touch event occurs, the user's finger generates capacitance with the sensing pad, and the voltage of the sensing pad after the touch is measured to perform fingerprint sensing. However, when such fingerprint recognition devices are attached to the display surface of electronic products, they reduce the visibility of the display surface, thus limiting the application of fingerprint recognition devices to specific locations on electronic products. Furthermore, the additional frame also increases the manufacturing cost of fingerprint recognition devices.

[0003] In view of the aforementioned improvements in the prior art, the inventors provide a voltage-sensing fingerprint recognition device and a fingerprint recognition method thereof to overcome the shortcomings of conventional fingerprint recognition devices. Summary of the Invention

[0004] The main objective of this invention is to provide a voltage-sensing fingerprint recognition device that can be applied to the display surface of electronic products without the need for an additional outer frame.

[0005] Another objective of the present invention is to provide a voltage-sensing fingerprint recognition device and a fingerprint recognition method thereof, which can enhance fingerprint sensing.

[0006] This invention provides a voltage-sensing fingerprint identification device and a fingerprint identification method thereof. The voltage-sensing fingerprint identification device of this invention includes: a substrate; a sensor disposed on the substrate, the sensor including a plurality of sensing pads arranged in a plurality of columns, each column having at least two sensing pads, each sensing pad receiving a trigger voltage; and a voltage extractor electrically connected to each sensing pad; when the voltage extractor extracts a sensing voltage value of the sensing pads in any column, the sensing pads in that column will stop receiving the trigger voltage.

[0007] In one embodiment of the voltage-sensing fingerprint recognition device of the present invention, the sensing pads in adjacent columns of the sensing pads in one column also stop receiving the trigger voltage.

[0008] In one embodiment of the voltage-sensing fingerprint recognition device of the present invention, the sensing pads, which are stopped from receiving trigger voltages, further receive an enhanced trigger voltage.

[0009] In one embodiment of the voltage-sensing fingerprint recognition device of the present invention, when the trigger voltage stops, the enhanced trigger voltage is simultaneously received, and the voltage values ​​of the trigger voltage and the enhanced trigger voltage are opposite in sign.

[0010] An embodiment of the voltage sensing fingerprint recognition device of the present invention, wherein the voltage extractor includes a sample-and-hold circuit (S / H) or a correlated double sampling (CDS) circuit.

[0011] One embodiment of the voltage-sensing fingerprint recognition device of the present invention further includes a dielectric layer encapsulated on the sensor.

[0012] The fingerprint recognition method of the voltage-sensing fingerprint recognition device of the present invention includes the following steps: providing a trigger voltage to a plurality of sensing pads, the sensing pads being arranged in a plurality of columns, each column having at least two sensing pads, and the sensing pads in each column being electrically connected to a voltage extractor; when the voltage extractor extracts at least one sensing voltage value of any column, the sensing pads in that column will stop receiving the trigger voltage; and the at least one sensing voltage value of the sensing pads in that column corresponds to the fingerprint shape on the sensing pads in that column.

[0013] In one embodiment of the fingerprint recognition method of the voltage sensing fingerprint recognition device of the present invention, the adjacent sensing pads of the sensing pads storing the sensing voltage values ​​also stop receiving the trigger voltage.

[0014] In one embodiment of the fingerprint recognition method of the voltage-sensing fingerprint recognition device of the present invention, the sensing pads that are stopped from receiving the trigger voltage further receive an enhanced trigger voltage.

[0015] In one embodiment of the fingerprint recognition method of the voltage sensing fingerprint recognition device of the present invention, when the trigger voltage stops, the enhanced trigger voltage is received simultaneously, and the voltage values ​​of the trigger voltage and the enhanced trigger voltage are opposite in sign.

[0016] Another voltage-sensing fingerprint recognition device of the present invention includes: a substrate;

[0017] A sensor disposed on the substrate includes a plurality of sensing pads arranged in a plurality of columns, each column having at least two sensing pads. Each sensing pad synchronously or asynchronously receives a trigger voltage and a boost trigger voltage.

[0018] A voltage sensor is electrically connected to each sensing pad;

[0019] When the voltage extractor extracts a sensing voltage value of the sensing pads in any column, the sensing pads in that column will stop receiving the trigger voltage and receive the enhanced trigger voltage. When the voltage extractor extracts another sensing voltage value of the sensing pads in that column, the sensing pads in that column will receive the trigger voltage and stop or receive the enhanced trigger voltage. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a side view of an embodiment of the voltage-sensing fingerprint recognition device of the present invention when touched by a finger.

[0022] Figure 2 This is a top-view schematic diagram of an embodiment of the voltage-sensing fingerprint recognition device of the present invention.

[0023] Figure 3 This is a circuit diagram of a voltage-sensing fingerprint recognition device according to an embodiment of the present invention, showing the finger touching the sensing pad.

[0024] Figure 4A for Figure 3 Circuit diagram Figure 1 Timing waveform diagram of the driving method.

[0025] Figure 4B for Figure 3 The circuit diagram shows the timing waveforms of another driving method.

[0026] Figure 5 This is a side view of another embodiment of the voltage-sensing fingerprint recognition device of the present invention when touched by a finger.

[0027] Figure 6 This is a top-view schematic diagram of another embodiment of the voltage-sensing fingerprint recognition device of the present invention.

[0028] Figure 7A This is a circuit diagram of the sensing pad of another embodiment of the voltage sensing fingerprint recognition device of the present invention.

[0029] Figure 7B This is a circuit diagram of another embodiment of the voltage-sensing fingerprint recognition device of the present invention when a finger touches the sensing pad.

[0030] Figure 8A for Figure 7A and 7B The timing waveform diagram of a synchronous drive circuit is shown in the schematic diagram.

[0031] Figure 8B for Figure 7A and 7B A circuit diagram showing the timing waveforms of an asynchronous drive.

[0032] Figure 8C for Figure 7A and7B Another asynchronous drive timing waveform diagram of the circuit schematic.

[0033] Figure 9 This is a flowchart illustrating the steps of a fingerprint recognition method of the voltage-sensing fingerprint recognition device of the present invention.

[0034] Among them, 1 is a substrate; 2 is a sensor; 21, 22 are sensing pads; 3 is a voltage harvester; 4 is a dielectric layer; 5 is a finger; C FG Finger capacitance; Cp capacitance; Cpar parasitic capacitance; Cplate capacitance; Cpump enhanced trigger capacitance; Cs_total sensing total capacitance; PIXEL sensing pixel; ROW1~ROWn sequence; S / H1 first sample-and-hold circuit; S / H2 second sample-and-hold circuit; S1 switch; V1 DC voltage; V2 finger voltage; Vpix sensing voltage value; Vpix_ph1 first phase sensing voltage; Vpix_ph2 second phase sensing voltage; Vtrig trigger voltage; Vtrig_BT enhanced trigger voltage. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Please refer to Figure 1 and Figure 2 An embodiment of the voltage-sensing fingerprint recognition device of the present invention includes: a substrate 1; a sensor 2 disposed on the substrate 1, and the sensor 2 including a plurality of sensing pads (21, 22), the sensing pads (21, 22) being arranged in a plurality of columns (ROW1 to ROWn), and each column having at least two sensing pads, each sensing pad receiving a trigger voltage Vtrig. Figure 2 The diagram only shows the state of the trigger voltage Vtrig applied to the sensing pad 21 at a certain time (in reality, the trigger voltage Vtrig can change over time and be supplied to each column); and a voltage extractor 3, electrically connected to each sensing pad (21, 22) (for simplicity and ease of description, the diagram is not shown). Figure 1 and Figure 2Only the multiple sensing pads 22 of column ROW3 are shown electrically connected to the voltage extractor 3. In fact, the multiple sensing pads (21, 22) of columns ROW1 to ROWn are all electrically connected to the voltage extractor 3 for accurate fingerprint sensing. When the voltage extractor 3 extracts a sensing voltage value Vpix of the sensing pads 22 in any column (such as ROW3), the sensing pads 22 in that column (ROW3) will stop receiving the trigger voltage Vtrig.

[0037] Furthermore, in order to ensure that the voltage extractor 3 can capture the sensing voltage Vpix of each row of sensing pads without interference, in this embodiment, the sensing pads 22 of the adjacent rows (ROW2 and ROW4) of the sensing pads 22 of ROW3 also stop receiving the trigger voltage Vtrig. This avoids interference from the trigger voltage Vtrig on the sensing pads 21 of ROW1 and ROW5, so as to more accurately measure the sensing voltage value Vpix on each row of sensing pads and identify the fingerprint on each row of sensing pads.

[0038] Furthermore, these sensing pads (21, 22) are composed of a plurality of sensing pixels. In this embodiment, the trigger voltage Vtrig can be provided to a plurality of columns of different regions of the sensor 2 in a time-division and sequential manner (similar to a scanning manner). For example, the trigger voltage Vtrig is provided in the aforementioned manner in some columns (ROW1 and ROW5 to ROWn), while the voltage is not provided in another part of the columns (ROW2 to ROW4). The voltage capture unit 3 captures and stores the sensing voltage of the plurality of sensing pads 22 in the middle column (ROW3) of the other part of the columns (ROW2 to ROW4) generated when touched. The voltage value Vpix is ​​then applied to the first row (ROW1-ROW2 and ROW6-ROWn), while the voltage is stopped for the second row (ROW3-ROW5). The voltage extractor 3 then captures and stores the sensing voltage value Vpix of the multiple sensing pads 22 in the middle row (ROW4) of the second row (ROW3-ROW5) generated during touch. This process is repeated to sense the sensing voltage value Vpix on each row of sensing pads and identify the fingerprint on each row of sensing pads.

[0039] The voltage acquisition unit 3 includes a sample-and-hold circuit (S / H) or a correlated double sampling circuit (CDS). Furthermore, it includes a dielectric layer 4 encapsulated on the sensor 2.

[0040] Please refer to this again. Figures 1 to 3When the sensing pad 21 receives the trigger voltage Vtrig, a sensing capacitance Cs is generated between a finger 5 and the sensing pad 22 in column ROW3 upon touch. A capacitance Cplate exists between the sensing pad 22 and the substrate 1, while another capacitance Cp exists between the finger 5 and the substrate 1, generating a finger capacitance C. FG And the voltage V2 of a finger. In addition, the sensing voltage value Vpix of the sensing pad 22 in ROW3 column is captured and stored by the voltage extractor 3. Based on the change of the obtained sensing voltage value Vpix, the occurrence of a touch event is determined and the fingerprint is sensed.

[0041] The relationship between the voltage and capacitance mentioned above is expressed in the following formula, where Cs_total is the total sensing capacitance of the sensing capacitance Cs:

[0042]

[0043]

[0044] Please refer to this again. Figure 2 , Figure 3 , Figure 4A and Figure 4B , Figure 4A for Figure 3 Circuit diagram Figure 1 Timing waveform diagram of the driving method, Figure 4A Before collecting the sensing voltage Vpix of the sensing pad 22 in the ROW3 column, a phase reset operation is required to remove residual charge from the time-division drive. Figure 4A In the initial state, switch S1 is off, and the second sensing pad 22 of column ROW3 is floating. At time t0, switch S1 is on, providing a DC voltage V1 to the sensing pad 22 of column ROW3 and resetting it. Then switch S1 is off, and at time t1, the trigger voltage Vtrig (not shown) couples with the finger 5 to generate the finger voltage V2. Figure 4B for Figure 3 The circuit diagram shows the timing waveforms of another driving method. Figure 4B The display is in the initial state, with switch S1 on (ON), and the DC voltage V1 is applied to the sensing pad 22 in column ROW3. Switch S1 is off (OFF) at time t0, and is turned on again at time t2. The finger voltage V2 is generated at time t1, at which point switch S1 is off.

[0045] also, Figures 5 to 8CAnother embodiment of the voltage-sensing fingerprint recognition device of the present invention is provided, which differs from the previous embodiment in that the sensing pads (21, 22) of each row (ROW1 to ROWn) in this embodiment further receive an enhanced trigger voltage Vtrig_BT, thereby enhancing fingerprint sensing. Furthermore, the sensing pads 22 of the row (ROW3) that are stopped from receiving the trigger voltage Vtrig further receive the enhanced trigger voltage Vtrig_BT (see [link to documentation]). Figure 6 and Figures 8A-8C Furthermore, the voltage values ​​of the trigger voltage Vtrig and the enhanced trigger voltage Vtrig_BT are opposite in sign.

[0046] Please refer to this again. Figures 5 to 8C More specifically, another embodiment of the voltage-sensing fingerprint recognition device of the present invention includes: a substrate 1; a sensor 2 disposed on the substrate 1, the sensor 2 including a plurality of sensing pads (21, 22), the sensing pads (21, 22) being arranged in a plurality of columns (ROW1~ROWn), and each column having at least two sensing pads, all sensing pads being synchronized (see [link to documentation]). Figure 8A ) or asynchronous (see Figure 8B and Figure 8C The sensor receives the trigger voltage Vtrig and the enhanced trigger voltage Vtrig_BT; and the voltage extractor 3 is electrically connected to each sensing pad (21, 22). (For simplicity of the diagram and ease of description, ...) Figure 5 and Figure 6 Only the multiple sensing pads 22 of column ROW3 are shown electrically connected to the voltage extractor 3. In fact, the multiple sensing pads (21, 22) of columns ROW1 to ROWn are all electrically connected to the voltage extractor 3 for accurate fingerprint sensing. When the voltage extractor 3 extracts a sensing voltage value Vpix of the sensing pads 22 in any column (such as ROW3), the sensing pads 22 in that column (ROW3) will stop receiving the trigger voltage Vtrig and receive the enhanced trigger voltage Vtrig_BT (see [link to relevant documentation]). Figures 8A-8C (See the schematic diagram of the first sample-and-hold circuit S / H1 in the diagram). When the voltage extractor 3 extracts another sensing voltage value Vpix of the sensing pads 22 in that row (ROW3), the sensing pads 22 in that row (ROW3) will receive the trigger voltage Vtrig (see [reference]). Figures 8A-8C (See the schematic diagram of the second sample-and-hold circuit S / H2 in the diagram), and stop (see...) Figure 8A (See the schematic diagram of the second sample-and-hold circuit S / H2) or receive the enhanced trigger voltage Vtrig_BT (see [link]). Figure 8B and 8C (Schematic diagram of the second sample-and-hold circuit S / H2).

[0047] Please refer to this again. Figure 5 , Figure 6 , Figure 7A and 7B The enhanced trigger voltage Vtrig_BT is applied to the sensing pad 22, generating an enhanced trigger capacitor Cpump, and a reference... Figure 7A and 7B The sensing pad 22 in ROW3 column has a parasitic capacitance Cpar between it and the substrate 1.

[0048] Figure 8A for Figure 7A and 7B The timing waveform diagram of the same-phase drive in the circuit diagram. Figure 8B for Figure 7A and 7B A timing waveform diagram of a non-inverting drive in the circuit schematic. Figure 8C for Figure 7A and 7B Another out-of-phase drive timing waveform diagram from the circuit schematic. Figure 8A In this process, the enhanced trigger voltage Vtrig_BT and the trigger voltage Vtrig are emitted simultaneously at the same time, so the enhanced trigger voltage Vtrig_BT and the trigger voltage Vtrig are synchronously driven. Figure 8B and Figure 8C The enhanced trigger voltage Vtrig_BT and the trigger voltage Vtrig are emitted at different times, so the enhanced trigger voltage Vtrig_BT and the trigger voltage Vtrig are asynchronously driven.

[0049] Figure 7A The finger 5 was not placed on the sensor pad 22 in column ROW3, ​​in combination with Figure 8A Taking synchronous drive as an example, first close the switch S1 to reset the sensing pad 22 of ROW3 column with a DC voltage V1, then open it to remove residual charge. Then, at time t1, simultaneously issue the enhanced trigger voltage Vtrig_BT and the trigger voltage Vtrig, and store the sensing voltages Vpix at different times in a first sample-and-hold circuit S / H1 and a second sample-and-hold circuit S / H2. At this time, Figure 5 The voltage extractor 3 is composed of the first sample-and-hold circuit S / H1 and the second sample-and-hold circuit S / H2.

[0050] like Figure 7A and Figure 8A Taking synchronous driving as an example, when the finger 5 is not placed on the sensing pad 22 in column ROW3, ​​the first sample-and-hold circuit S / H1 and the second sample-and-hold circuit S / H2 respectively capture the first phase sensing voltage Vpix_ph1 and the second phase sensing voltage Vpix_ph2 (not shown). The relationship between the two and related voltages and capacitances is as follows:

[0051] When switch S1 is turned on, V pix_ph1 =V1…(3)

[0052]

[0053] Equation (4) assumes that the parasitic capacitance Cpar is very small. Close to 1.

[0054] like Figure 7B and Figure 8A Taking synchronous driving as an example, when the finger 5 is placed on the sensing pad 22 in column ROW3, ​​the relationship between the voltage and capacitance is as follows:

[0055] When switch S1 is turned on, V pix_ph1 =V1…(5)

[0056]

[0057]

[0058] Equation (7) represents the value of ΔV when touched by a finger. pix Depend on The increased trigger voltage Vtrig_BT can increase the sensing voltage Vpix, thus enhancing the fingerprint recognition effect of each row of sensing pads 22.

[0059] Please refer to Figure 1 , Figure 2 and Figure 9 An embodiment of the fingerprint recognition method of the voltage-sensing fingerprint recognition device of the present invention includes the following steps:

[0060] Step 1: Provide a trigger voltage Vtrig to a plurality of sensing pads (21, 22), which are arranged in a plurality of columns (ROW1 ~ ROWn), each column having at least two sensing pads, and the sensing pads (21, 22) in each column are electrically connected to a voltage acquisition device 3.

[0061] Step 2: When the voltage acquisition unit 3 acquires the voltage value Vpix of a sensing pad in any column, the sensing pads 22 in that column (e.g., ROW3) will stop receiving the trigger voltage Vtrig; and

[0062] Step 3: The sensing voltage value Vpix of the sensing pads 22 in this column (ROW3) corresponds to the fingerprint shape on this column (ROW3).

[0063] Among them, the adjacent sensing pads (such as ROW2 and ROW4) of the sensing pads 22 in the column (ROW3) where the sensing pad voltage value Vpix is ​​captured also stop receiving the trigger voltage Vtrig. Furthermore, the sensing pads (such as ROW2 to ROW4) that have stopped receiving the trigger voltage Vtrig, such as... Figure 6 As shown, a reinforced trigger voltage Vtrig_BT is further received, and the voltage values ​​of the trigger voltage Vtrig and the reinforced trigger voltage Vtrig_BT are opposite in sign.

[0064] In summary, the voltage-sensing fingerprint recognition device and its fingerprint recognition method of the present invention do not require an additional outer frame and can be applied to the display surface of electronic products, thereby enhancing the fingerprint recognition effect.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A voltage sensing fingerprint recognition device, characterized in that: include: a substrate; a sensor disposed on the substrate, the sensor comprising a plurality of sensing pads, the sensing pads being arranged in a plurality of rows, each row having at least two sensing pads, each sensing pad receiving a trigger voltage; and A voltage collector electrically connected to each sensing pad; When the voltage capturer captures a sensing voltage value of the sensing pads in any row, the sensing pads in the row will all stop receiving the trigger voltage, and the sensing pads in the adjacent rows of the sensing pads in the row will also all stop receiving the trigger voltage.

2. The voltage sensing fingerprint recognition device according to claim 1, characterized in that: The sensing pads that stop receiving the trigger voltage further receive an enhanced trigger voltage.

3. The voltage sensing fingerprint recognition device according to claim 2, characterized in that: When the trigger voltage stops, the enhanced trigger voltage is received at the same time, and the voltage values ​​of the trigger voltage and the enhanced trigger voltage are opposite in sign.

4. The voltage sensing fingerprint recognition device according to claim 1, characterized in that: The voltage capture device includes a sample-and-hold circuit (S / H) or a correlated double sampling circuit (CDS).

5. The voltage sensing fingerprint recognition device according to claim 1, characterized in that: The invention further comprises a dielectric layer packaged on the sensor.

6. A fingerprint recognition method of a voltage sensing fingerprint recognition device, characterized in that the steps include: Providing a trigger voltage to a plurality of sensing pads, wherein the sensing pads are arranged in a plurality of rows, each row having at least two sensing pads, and the sensing pads in each row are electrically connected to a voltage capture device; When the voltage capturer captures at least one sensing voltage value of any column, the sensing pads of the column will all stop receiving the trigger voltage, and the adjacent sensing pads of the sensing pads storing the sensing voltage value will also all stop receiving the trigger voltage; and At least one sensing voltage value of the sensing pads in the row corresponds to the fingerprint shape on the sensing pads in the row.

7. The fingerprint recognition method according to claim 6, characterized in that: The sensing pads that stop receiving the trigger voltage further receive an enhanced trigger voltage.

8. The fingerprint recognition method according to claim 7, characterized in that: When the trigger voltage stops, the enhanced trigger voltage is received at the same time, and the voltage values ​​of the trigger voltage and the enhanced trigger voltage are opposite in sign.

9. A voltage sensing fingerprint recognition device, characterized in that: include: a substrate; a sensor disposed on the substrate, the sensor comprising a plurality of sensing pads arranged in a plurality of rows, each row having at least two sensing pads, each sensing pad receiving a trigger voltage and an enhanced trigger voltage synchronously or asynchronously; and A voltage collector electrically connected to each sensing pad; When the voltage capturer captures a sensing voltage value of the sensing pads in any column, the sensing pads in the column will all stop receiving the trigger voltage and receive the enhanced trigger voltage, and the sensing pads in adjacent columns of the sensing pads in the column will also all stop receiving the trigger voltage. When the voltage capturer captures another sensing voltage value of the sensing pads in the column, the sensing pads in the column will receive the trigger voltage and stop or receive the enhanced trigger voltage.

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