Electronic circuit having display driving function, touch sensing function and fingerprint sensing function

An electronic circuit adapted to process fingerprint data from a panel including touch sensors and fingerprint sensors is provided. The electronic circuit includes a first circuit, a second circuit and a control circuit. The first circuit is configured to receive touch sensing signals from the touch sensors. The second circuit is configured to receive fingerprint sensing signals corresponding to at least one fingerprint imprint from the fingerprint sensors via fingerprint sensing lines. The control circuit is configured to determine a fingerprint touch area according to the touch sensing signals, and select a subset of the fingerprint sensing lines to form a fingerprint sensing zone adapted for a fingerprint sensing operation and including at least one boundary based on the determined fingerprint touch area. The subset of fingerprint sensing lines is selected based on the at least one boundary of the fingerprint sensing zone. An electronic device and a method for sensing at least one fingerprint imprint from a panel are also provided.

BACKGROUND

Technical Field

The invention relates to an electronic circuit, an electronic device and a sensing method, more specifically, to an electronic circuit and an electronic device adapted to drive a panel including touch sensors and fingerprint sensors, and a method for sensing at least one fingerprint imprint from a panel.

Description of Related Art

In recent years, demands for fingerprint sensing have been gradually increased. In order to reduce a volume of an electronic device, a fingerprint sensing region may overlap with a display region of the electronic device. For example, an under-display fingerprint identification technique is to embed fingerprint sensors to a display panel, and the fingerprint sensor may sense or capture a fingerprint image through the display panel. When a touch event such as fingerprint identification happens, a touch sensing circuit may report it to an application processor of the electronic device via a specified interface. Next, the application processor further controls a display driving circuit to drive the display panel to display image for fingerprint sensing. On the other hand, the application processor further controls a fingerprint sensing circuit to perform the fingerprint sensing operation. The fingerprint sensing circuit transmits sensing information to the application processor for fingerprint identification after the fingerprint sensing operation, and then the application processor completes the fingerprint identification according to the sensing information.

However, the display panel may be divided into a plurality of fingerprint sensing zones in a fingerprint sensing direction X that fingerprint sensing lines are arranged, as illustrated inFIG.18.FIG.18illustrates two display panels that are respectively divided into a plurality of fingerprint sensing zones of different sizes in the fingerprint sensing direction X in the related art. The fingerprint sensing zones have also been partitioned in the scan direction Y. Partition of the fingerprint sensing zones is determined and fixedly configured as the electronic device is manufactured. The size of the fingerprint sensing zones in each display panel is constant. In some cases, the finger may touch many fingerprint sensing zones, and the fingerprint image crosses over the touched fingerprint sensing zones in the fingerprint sensing direction X. The fingerprint sensing circuit has to receive fingerprint sensing signals zone by zone, such that a cross zone problem in receiving the fingerprint sensing signals of a fingerprint image is raised. In case of cross zone receiving, the fingerprint sensing circuit has to spend time for switching and re-initialization. That is to say, it may spend more time for fingerprint sensing and identification since the fingerprint sensing signals are received zone by zone.

SUMMARY

The invention is directed to an electronic circuit and an electronic device, capable of providing an efficient method for fingerprint sensing and identification and good user experience for users. In addition, a method for sensing at least one fingerprint imprint from a panel is also provided.

The invention provides an electronic circuit, adapted to process fingerprint data from a panel including touch sensors and fingerprint sensors. The electronic circuit includes a first circuit, a second circuit and a control circuit. The first circuit is configured to receive touch sensing signals from the touch sensors. The second circuit is configured to receive fingerprint sensing signals corresponding to at least one fingerprint imprint from the fingerprint sensors via fingerprint sensing lines. The control circuit is configured to determine a fingerprint touch area according to the touch sensing signals, and select a subset of the fingerprint sensing lines to form a fingerprint sensing zone adapted for a fingerprint sensing operation and including at least one boundary based on the determined fingerprint touch area. The subset of fingerprint sensing lines is selected based on the at least one boundary of the fingerprint sensing zone.

The invention provides an electronic device including a panel and an electronic circuit. The panel includes touch sensors and fingerprint sensors. The electronic circuit is coupled to the panel. The electronic circuit is adapted to receive touch sensing signals from the touch sensors and receive fingerprint sensing signals corresponding to at least one fingerprint image from the fingerprint sensors via fingerprint sensing lines of the panel. The electronic circuit includes a control circuit. The control circuit is configured to determine a fingerprint touch area according to the touch sensing signals, and select a subset of fingerprint sensing lines to form a fingerprint sensing zone adapted for a fingerprint sensing operation according to the determined fingerprint touch area. Each of the fingerprint sensing lines in the subset of fingerprint sensing lines is selected based on a boundary of the fingerprint sensing zone.

The invention provides a method for sensing at least one fingerprint imprint from a panel comprising touch sensors and fingerprint sensors. The fingerprint sensors are coupled to fingerprint sensing lines. The method includes: determining a touch area according to touch sensing signals from the touch sensors; selecting a subset of the fingerprint sensing lines to form a fingerprint sensing zone having at least a boundary and adapted for a fingerprint sensing operation based on the determined fingerprint touch area, where the subset of fingerprint sensing lines is selected based on the boundary of the fingerprint sensing zone; and receiving fingerprint sensing signals via the subset of fingerprint sensing lines.

DESCRIPTION OF THE EMBODIMENTS

Embodiments are provided below to describe the disclosure in detail, though the disclosure is not limited to the provided embodiments, and the provided embodiments can be suitably combined. The term “coupling/coupled” or “connecting/connected” used in this specification (including claims) of the application may refer to any direct or indirect connection means. For example, “a first device is coupled to a second device” should be interpreted as “the first device is directly connected to the second device” or “the first device is indirectly connected to the second device through other devices or connection means.” In addition, the term “signal” can refer to a current, a voltage, a charge, a temperature, data, electromagnetic wave or any one or multiple signals.

FIG.1is a schematic block diagram illustrating an electronic device according to an embodiment of the invention. Referring toFIG.1, the electronic device100of the present embodiment includes an electronic circuit110and a display panel120. The display panel120includes touch sensors and fingerprint sensors. The electronic circuit110is configurable to be coupled to the display panel120. The electronic circuit110is adapted to drive the display panel120.

In the present embodiment, the electronic device100may be an electronic device having a display function, a touch sensing function and a fingerprint sensing function. In an embodiment, the electronic device100may be, but not limited to, a smartphone, a non-smart phone, a wearable electronic device, a tablet computer, a personal digital assistant, a notebook and other portable electronic devices that can operate independently and have the display function, the touch sensing function and the fingerprint sensing function. In an embodiment, the electronic device100may be, but not limited to, a portable or un-portable electronic device in a vehicle intelligent system. In an embodiment, the electronic device100may be, but not limited to, intelligent home appliances such as, a television, a computer, a refrigerator, a washing machine, a telephone, an induction cooker, a table lamp and so on.

FIG.2is a schematic diagram illustrating the display panel depicted inFIG.1. Referring toFIG.2, the display panel120of the present embodiment includes a plurality of display pixels122, a plurality of touch sensors124and a plurality of fingerprint sensors126. The electronic circuit110drives and controls the display panel120to perform a display operation, a touch sensing operation and a fingerprint sensing operation. To be specific, the electronic circuit110drives and controls the display pixels122to display images via display scan lines GDL and display data lines SDL. The electronic circuit110also drives and controls the touch sensors124to sense a touch event of the display panel120via touch scan lines and touch sensing lines TSL. In an embodiment, the touch sensors124may be touch sensing electrodes in a touch sensing phase, and the touch sensors124may be common electrodes in a display phase. In the present embodiment, in-cell touch sensors are depicted inFIG.2as an example. For the in-cell touch sensors, the display panel120inherently has no touch scan lines. For other type touch sensors, the display panel120may have touch scan lines for transmitting touch driving signals. The electronic circuit110also drives and controls the fingerprint sensors126to sense a fingerprint image on the display panel120via fingerprint scan lines GSL and fingerprint sensing lines FSL.

In an embodiment, the display panel120may be an in-cell fingerprint, touch and display panel that the fingerprint sensors and the touch sensors are embedded, but the invention is not limited thereto. In an embodiment, the electronic circuit110may drive and control the electronic device100to perform an in-display fingerprint identification operation, i.e. fingerprint recognition operation. In an embodiment, the fingerprint sensors126may be optical fingerprint sensors.

FIG.3is a schematic block diagram illustrating the electronic circuit depicted inFIG.1. Referring toFIG.3, the electronic circuit110may include a display driving circuit112, a fingerprint sensing circuit116and a touch sensing circuit114. The display driving circuit112is configured to drive and control the display pixels122to display images via the display scan lines GDL and the display data lines SDL. The display driving circuit112generates display driving signals for driving the display data lines SDL of the display panel120. The display driving circuit112may include a timing controller121, a display driver and other functional circuits for the display operation. The display driving circuit112may also include other controllers or processors123for other control activities of the display operation. The touch sensing circuit114is configured to drive and control the touch sensors124to sense the touch event of the display panel120via the touch sensing lines TSL. The touch sensing circuit114may include a touch controller141, an analog front end (AFE) circuit, an analog-to-digital converter (ADC) circuit and other functional circuits for the touch sensing operation. The fingerprint sensing circuit116is configured to drive and control the fingerprint sensors126to sense the fingerprint on the display panel120via the fingerprint scan lines GSL and the fingerprint sensing lines FSL. The fingerprint sensing circuit116receives fingerprint sensing signals corresponding to a fingerprint image from the fingerprint sensors126and may also process the fingerprint sensing signals to obtain the fingerprint image. The fingerprint sensing circuit116may include a digital circuit161, an AFE circuit, an ADC circuit and other functional circuits for the fingerprint sensing operation.

In an embodiment, when the electronic circuit110is implemented as a single chip integrated circuit that can drive and control the display panel120to perform the display operation, the touch sensing operation and the fingerprint sensing operation, the electronic circuit110may include a control circuit130, and the control circuit130may be a micro-controller based core to perform all of control activities of the display operation, the touch sensing operation and the fingerprint sensing operation. The control circuit130may include at least one of the timing controller121, the touch controller141, the digital circuit161, and the other controllers or processors123of the display driving circuit112.

The display driving circuit112, the touch sensing circuit114and the fingerprint sensing circuit116communicate with one another via signal transmission interfaces, such as Mobile Industry Processor Interface (MIPI), Inter-Integrated Circuit (I2C) Interface, Serial Peripheral Interface (SPI) and/or other similar or suitable interfaces.

Regarding hardware structures of the components in the embodiment ofFIG.3, the timing controller121, the touch controller141and the digital circuit161may be a processor having computational capability. Alternatively, the timing controller121, the touch controller141and the digital circuit161may be designed through hardware description languages (HDL) or any other design methods for digital circuits familiar to people skilled in the art and may be hardware circuits implemented through a field programmable gate array (FPGA), a complex programmable logic device (CPLD), or an application-specific integrated circuit (ASIC). In addition, enough teaching, suggestion, and implementation illustration for hardware structures of the display driving circuit112, the touch sensing circuit114and the fingerprint sensing circuit116can be obtained with reference to common knowledge in the related art, which is not repeated hereinafter.

FIG.4is a schematic diagram illustrating a display panel operating for fingerprint sensing according to an embodiment of the invention. Referring toFIG.1,FIG.3andFIG.4, the electronic circuit110may drive and control the display panel120to sense one or more fingerprint images FPI_1, FPI_2, FPI_3and FPI_4on the display panel120. In the present embodiment, the fingerprint sensing lines FSL extend in the direction Y, e.g. the vertical direction and arranged in the direction X, e.g. the horizontal direction, as shown inFIG.2. The display panel120is not fixedly partitioned into fingerprint sensing zones for fingerprint sensing in the direction X in advance. That is to say, the display panel120has no predetermined fingerprint sensing zones for the fingerprint sensing lines FSL in the arrangement direction X. In related art as illustrated inFIG.18, the display panel is fixedly partitioned into fingerprint sensing zones for fingerprint sensing in the direction X in advance. The fingerprint sensing zones401,402,403and404of the present embodiment can be flexibly formed for fingerprint sensing by selecting a part of the fingerprint sensing lines FSL among a plurality of the fingerprint sensing lines FSL arranged all over the display panel120. Each of the fingerprint sensing lines FSL is selectable to be boundaries of the fingerprint sensing zones401,402,403and404.

To be specific, a control circuit of the touch sensing circuit114, e.g. a touch controller, determines one or more touch areas TSA corresponding to the fingerprint image FPI_1, FPI_2, FPI_3and FPI_4according to a touch sensing signal. The touch controller141(as illustrated inFIG.5) may determine a range for each of the touch areas TSA. Alternatively, the touch controller141may simply determine coordinate information indicating a location of each of the touch areas TSA and informs the fingerprint sensing circuit116of the coordinate information. The determined touch area TSA defines a fingerprint sensing zone for covering a fingerprint image. The fingerprint sensing zone may cover a portion or a full range of the fingerprint image. The portion or the full range of the input fingerprint image includes sufficient fingerprint features for fingerprint identification. The touch controller informs the fingerprint sensing circuit116to select a part of the fingerprint sensing lines FSL and a part of the fingerprint scan lines GSL for the fingerprint sensing operation according to the determined touch area TSA. A part of the fingerprint sensing lines FSL collocated with the touch area TSA on the display panel120is selected among a plurality of the fingerprint sensing lines FSL arranged all over the display panel120. In the present embodiment, the selected part of fingerprint sensing lines FSL may flexibly form a single fingerprint sensing zone401,402,403or404having a range determined by the touch area TSA, such that only a single-turn receiving of fingerprint sensing signals in fingerprint sensing channels is required for the horizontal direction (X direction) of the fingerprint image FPI_1, FPI_2, FPI_3or FPI_4. It is thus to solve cross zone problem in receiving the fingerprint sensing signals of a fingerprint image FPI_1, FPI_2, FPI_3or FPI_4in the horizontal direction. The time for fingerprint sensing is thus reduced.

FIG.5is a schematic block diagram illustrating an electronic device according to another embodiment of the invention. Referring toFIG.5, the electronic device200of the present embodiment includes the electronic circuit110, the display panel120and an application processor230. The electronic circuit110includes the touch sensing circuit114, the fingerprint sensing circuit116, a plurality of interface circuits IF1, IF2and IF3and a plurality of switch circuits117and118. The first interface circuit IF1includes circuits for transmitting and receiving signals arranged in the touch sensing circuit114and/or the fingerprint sensing circuit116. The touch sensing circuit114communicates with the fingerprint sensing circuit116via the first interface circuit IF1. The second interface circuit IF2is coupled between the touch sensing circuit114and the application processor230. The touch sensing circuit114transmits touch information to the application processor230via the second interface circuit IF2. For simplicity and clarity, the display driving circuit112is not depicted in details inFIG.5.

The display panel120includes scan circuits201and203. The scan circuits201and203are coupled to the fingerprint sensors126via the fingerprint scan lines GSL. The fingerprint scan lines GSL (not shown inFIG.5) extend in the direction X. The scan circuits201and203are configured to initiate a fingerprint scanning to a fingerprint sensing zone405via the corresponding fingerprint scan lines GSL, so as to control the fingerprint sensors126of the fingerprint sensing zone405to perform the fingerprint sensing operation.

In the present embodiment, the electronic circuit110co-operates with the display panel120and the application processor230for a fingerprint identification operation, i.e. a fingerprint recognition operation or fingerprint authentication operation. The third interface circuit IF3is coupled between the fingerprint sensing circuit116and the application processor230. The fingerprint sensing circuit116outputs a fingerprint image to the application processor230to perform the fingerprint identification operation via the third interface circuit IF3. Enough teaching, suggestion, and implementation illustration for the fingerprint identification operation can be obtained with reference to common knowledge in the related art, which is not repeated hereinafter. In addition, the interface circuits IF1, IF2and IF3may be Mobile Industry Processor Interfaces (MIPI), Inter-Integrated Circuit (I2C) Interfaces, Serial Peripheral Interfaces (SPI) and/or other similar or suitable interfaces, but the invention is not limited thereto.

The touch sensing circuit114is configured to receive a touch sensing signal S1from the touch sensors124. The touch sensing circuit114includes a touch controller141and a converter circuit143. The converter circuit143includes an analog front end (AFE) circuit, a sample and hold (S/H) circuit and an analog-to-digital converter (ADC) circuit. The converter circuit143receives the touch sensing signal S1from the touch sensors124via the switch circuit117. The switch circuit117is for multiplexing touch sensing signals S1and display driving signals in respective touch sensing phases and display driving phases. The converter circuit143converts the touch sensing signal S1of an analog format into the touch sensing signal S1of a digital format and transmits the touch sensing signal S1of the digital format to the touch controller141. Enough teaching, suggestion, and implementation illustration for the operation and hardware structures of the converter circuit143can be obtained with reference to common knowledge in the related art, which is not repeated hereinafter.

The touch controller141receives the touch sensing signal S1from the converter circuit143. The touch controller141determines the touch area TSA according to the touch sensing signal S1. In the present embodiment, the touch area TSA may correspond to N fingerprint sensing channels in the X direction and cover a plurality of fingerprint scan zones in the Y direction. The touch controller141informs the fingerprint sensing circuit116to select a part of the fingerprint sensing lines FSL and a part of the fingerprint scan lines GSL for fingerprint sensing operation according to the determined touch area TSA. For example, the fingerprint sensing lines FSL and the fingerprint scan lines GSL corresponding to the fingerprint sensing zone405are selected to perform the fingerprint sensing operation. In the present embodiment, the number of the selected fingerprint sensing channels is N, where N is a positive integer.

The fingerprint sensing circuit116is configured to receive a fingerprint sensing signal S3corresponding to a fingerprint image FPI_5from the fingerprint sensors126via the selected part of the fingerprint sensing lines FSL and the switch circuit118. The fingerprint sensing circuit116includes a digital circuit161, a converter circuit163and gate drivers165_1and165_2.

The converter circuit163converts the fingerprint sensing signal S3of an analog format into the fingerprint sensing signal S3of a digital format and transmits the fingerprint sensing signal S3of the digital format to the digital circuit161. The converter circuit163includes a plurality of fingerprint sensing channels coupled to the switch circuit118. The fingerprint sensing channels receive the corresponding fingerprint sensing signal S3from the selected part of the fingerprint sensing lines FSL. Preferably, the fingerprint sensing signal S3carried on the selected part of the fingerprint sensing lines FSL is read out and received by the fingerprint sensing channels at a time. Each of the fingerprint sensing channels may include an AFE circuit and/or an ADC circuit. In the present embodiment, the converter circuit163may include N fingerprint sensing channels, and the display panel120may include M fingerprint sensing lines FSL, where N and M are positive integers, and M is larger than N. That is to say, the number of the fingerprint sensing lines FSL is larger than the number of the fingerprint sensing channels. Enough teaching, suggestion, and implementation illustration for the operation and hardware structures of the converter circuit163can be obtained with reference to common knowledge in the related art, which is not repeated hereinafter.

The touch controller141communicates with the digital circuit161via the first interface circuit IF1. The digital circuit161controls the switch circuit118to select a part of the fingerprint sensing lines for the fingerprint sensing operation via a control signal S5. For example, N fingerprint sensing lines collocated with the touch area TSA on the display panel120is selected among M fingerprint sensing lines arranged all over the display panel120. The switch circuit118is coupled to the fingerprint sensors126via the fingerprint sensing lines FSL. The switch circuit118is configured to receive the fingerprint sensing signal S3from the fingerprint sensors126via the selected fingerprint sensing lines FSL. The switch circuit118may include a plurality of switches, and each of the switches corresponds to a fingerprint sensing line FSL as depicted inFIG.6. The digital circuit161controls the switch circuit118to turn on a part of the plurality of switches corresponding to the N fingerprint sensing lines to establish coupling between the N fingerprint sensing lines and the N fingerprint sensing channels for the fingerprint sensing operation. On the other hand, the digital circuit161controls the switch circuit118to turn off the rest of the plurality of switches corresponding to the rest of the fingerprint sensing lines that is not selected. For example, the switches corresponding to the unselected M-N fingerprint sensing lines are turned off.

The digital circuit161controls the gate drivers165_1and165_2to drive the scan circuits201and203to initiate the fingerprint scanning to the fingerprint sensing zone405via a driving signal S4. In an embodiment, the display panel120may simply include a gate driver, and the number of the gate drivers does not intend to limit the invention. Enough teaching, suggestion, and implementation illustration for the operation and hardware structures of the gate drivers165_1and165_2and the scan circuits201and203can be obtained with reference to common knowledge in the related art, which is not repeated hereinafter.

In the present embodiment, the determined touch area TSA defines the fingerprint sensing zone405for covering a fingerprint image. A part of the fingerprint sensing lines FSL and a part of the fingerprint scan lines GSL are selected for fingerprint sensing operation according to the determined touch area TSA. A part of switches corresponding to the part of fingerprint sensing lines FSL is turned on to couple the part of fingerprint sensing lines FSL to the fingerprint sensing channels to have the fingerprint sensing channels receive the fingerprint sensing signal S3. A part of the fingerprint sensing lines FSL collocated with the touch area TSA on the display panel120is selected among a plurality of the fingerprint sensing lines FSL arranged all over the display panel120. In the present embodiment, the selected part of fingerprint sensing lines FSL may flexibly form a single fingerprint sensing zone405having a range determined by the touch area TSA, and the fingerprint sensing signals S3carried on the selected part of fingerprint sensing lines FSL may be read out at a time, such that only a single-turn receiving of fingerprint sensing signals in fingerprint sensing channels is required for the horizontal direction X of the fingerprint image FPI_5. The time for fingerprint sensing is thus reduced.

In an embodiment, the electronic circuit110is implemented in a single semiconductor chip. In an embodiment, the electronic circuit110is implemented in at least two semiconductor chips. The at least two semiconductor chips include a first semiconductor chip and a second semiconductor chip. The first semiconductor chip includes the touch sensing circuit114. The second semiconductor chip includes the fingerprint sensing circuit116. The second semiconductor chip may also include the switch circuit118.

Regarding hardware structures of the components in the embodiment ofFIG.5, the touch controller141and the digital circuit161may be processors having computational capability. Alternatively, the touch controller141and the digital circuit161may be designed through hardware description languages (HDL) or any other design methods for digital circuits familiar to people skilled in the art and may be hardware circuits implemented through a field programmable gate array (FPGA), a complex programmable logic device (CPLD), or an application-specific integrated circuit (ASIC).

FIG.6is a schematic diagram illustrating a detail structure of the switch circuit118depicted inFIG.5according to an embodiment of the invention. Referring toFIG.6, the switch circuit118is controlled by the digital circuit161. The switch circuit118includes a plurality of switches SW. The switches SW can be separately controlled. The digital circuit161determines which switches to be turned on or turned off according to the touch area TSA. The switches SW that are turned on establish the coupling between the fingerprint sensing lines FSL and the fingerprint sensing channels for the fingerprint sensing operation.

In the present embodiment, the electronic circuit110further includes a wire circuit119coupled between the switch circuit118and the converter circuit163for reducing the circuit area. The wire circuit119groups the fingerprint sensing lines FSL into a plurality of groups, and the groups are correspondingly connected to the fingerprint sensing channels in the converter circuit163. For example, the converter circuit163may be designed to have 200 fingerprint sensing channels, and the number of the fingerprint sensing lines FSL is 1000. The first fingerprint sensing line, the 201thfingerprint sensing line, the 401thfingerprint sensing line, the 601thfingerprint sensing line and the 801thfingerprint sensing line are connected with one another in the same group via the corresponding switches SW and the wire circuit119and coupled to the first fingerprint sensing channel. Similarly, the second fingerprint sensing line, the 202thfingerprint sensing line, the 402thfingerprint sensing line, the 602thfingerprint sensing line and the 802thfingerprint sensing line are connected with one another in the same group via the corresponding switches SW and the wire circuit119and coupled to the second fingerprint sensing channel. The connection relationship of the rest fingerprint sensing lines and the rest fingerprint sensing channels can be deduced by analogy. By controlling the corresponding switches SW, the fingerprint sensing lines FSL in the same group are not shorted at the same time.

The number of the fingerprint sensing lines FSL, the number of the fingerprint sensing channels and the connection relationship of the fingerprint sensing lines FSL and the fingerprint sensing channels are disclosed for example, and the invention is not limited thereto.

FIG.7is a schematic diagram illustrating a method for selecting the fingerprint sensing lines depicted inFIG.5according to an embodiment of the invention. Referring toFIG.6andFIG.7, for example, the converter circuit163may be designed to have 200 fingerprint sensing channels, and the number of the fingerprint sensing lines FSL is 1000. When the touch controller141determines the touch area TSA with a coordinate (X, Y) of (652, 305) indicating a center or near center of the touch area and informs the digital circuit161of the coordinate information, the digital circuit161selects 200 fingerprint sensing lines FSL among 1000 fingerprint sensing lines FSL arranged all over the display panel120for fingerprint sensing, and each of the fingerprint sensing lines is selectable to be a boundary of the fingerprint sensing zone. For example, the digital circuit161controls the switch circuit118to select the 553thfingerprint sensing line FSL_553to the 752thfingerprint sensing line FSL_752to form the fingerprint sensing zone405for fingerprint sensing according to the X coordinate information of the touch area TSA, where the 553thfingerprint sensing line FSL_553and the 752thfingerprint sensing line FSL_752are selectable and selected to be boundaries of the fingerprint sensing zone405. That is to say, the fingerprint sensing lines of the boundaries of the fingerprint sensing zone405are determined according to the touch area TSA.

In the present embodiment, the touch area TSA includes a full range of the fingerprint image FPI_5, and has a center vertical line CL passing through the center or near center of the touch area TSA. The middle fingerprint sensing line FSL_652or FSL_653of the selected fingerprint sensing lines FSL_553to FSL_752is located on or near to the center vertical line CL of the determined touch area TSA. In this case, the fingerprint sensing line FSL_652is located on the center vertical line CL of the determined touch area TSA, and the fingerprint sensing line FSL_653is near to the center vertical line CL of the determined touch area TSA.

On the other hand, according to the Y coordinate information of the determined touch area TSA, the digital circuit161further controls the gate drivers165_1and/or165_2to drive the scan circuits201and/or203to initiate the fingerprint scanning to the fingerprint sensing zone405via the driving signal S4.

FIG.8is a flowchart illustrating steps in a method for sensing at least one fingerprint image according to an embodiment of the invention. Referring toFIG.5andFIG.8, in the present embodiment, the method for sensing the at least one fingerprint image is at least adapted to the electronic device200depicted inFIG.5, but the disclosure is not limited thereto. Taking the electronic device200for example, in step S100, the electronic circuit110determines a touch area TSA according to touch sensing signals S1from the touch sensors124. In step S110, the electronic circuit110selects a part of the fingerprint sensing lines FSL to form the fingerprint sensing zone405for the fingerprint sensing operation according to the determined touch area TSA. In step S120, the electronic circuit110receives fingerprint sensing signals S3via the part of the fingerprint sensing lines FSL.

The method for sensing the at least one fingerprint image described in the embodiment of the invention is sufficiently taught, suggested, and embodied in the embodiments illustrated inFIG.1toFIG.7, and therefore no further description is provided herein.

FIG.9is a flowchart illustrating detail steps in a method for fingerprint identification according to an embodiment of the invention. Referring toFIG.5andFIG.9, in the present embodiment, the method for fingerprint identification is at least adapted to the electronic device200depicted inFIG.5, but the disclosure is not limited thereto. Taking the electronic device200for example, in step S200, the touch controller141performs a touch sensing operation to determine the touch area TSA according to the touch sensing signal S1from the touch sensors124. In step S210, the digital circuit161controls the switch circuit118to select a part of the fingerprint sensing lines FSL for the fingerprint sensing operation. In step S220, the digital circuit161selects a part of the fingerprint scan lines GSL for the fingerprint sensing operation according to the determined touch area TSA. In step S230, the digital circuit161receives the fingerprint sensing signal S3via the part of the fingerprint sensing lines FSL. In step S240, the application processor230receives the fingerprint image from the digital circuit161and performs the fingerprint identification operation.

The method for fingerprint identification described of the embodiment of the invention is sufficiently taught, suggested, and embodied in the embodiments illustrated inFIG.1toFIG.7, and therefore no further description is provided herein.

FIG.10AandFIG.10Bare schematic diagrams illustrating a method for selecting the fingerprint sensing lines and the fingerprint scan lines according to an embodiment of the invention. Referring toFIG.10AandFIG.10B, the converter circuit163may be designed to have 200 fingerprint sensing channels, and the number of the fingerprint sensing lines FSL is 1000. The number of the fingerprint sensing lines FSL and the number of the fingerprint sensing channels are disclosed for example, and the invention is not limited thereto. The touch controller141determines the coordinate (X, Y) of the touch area TSA6as (629,992) and informs the digital circuit161of the coordinate information. The digital circuit161selects the fingerprint sensing lines RX529to RX728for sensing a fingerprint image FPI_6via the switch circuit118according to the X coordinate information of the touch area TSA6, and the fingerprint sensing lines RX529and RX728are selected to be boundaries of the fingerprint sensing zone406. Fingerprint sensing zones of the display panel120are not determined for each of the fingerprint sensing lines in advance. Therefore, the fingerprint sensing lines are flexibly selected to form the fingerprint sensing zone406having a range determined by the touch area TSA6. The digital circuit161selects and drives the fingerprint scan lines ROW960to ROW1056according to the Y coordinate information of the touch area TSA6. The fingerprint sensing signals carried on the fingerprint sensing lines RX529to RX728are read out at a time.

InFIG.10B, the method for selecting the fingerprint scan lines ROW960to ROW1056is further described in detail. In the present embodiment, the display panel120includes a plurality of scan zones. The determined touch area TSA6may cover over three scan zones which are located between the fingerprint scan lines ROW960to ROW1056. The digital circuit161drives the gate drivers165_1and/or165_2as illustrated inFIG.5to output scan signals STV5to STV7to the scan circuits201and/or203according to the Y coordinate information of the touch area TSA6. The scan signals STV5to STV7respectively correspond to the three scan zones covered by the touch area TSA6for the scan circuits201and/or203to initiate scanning of the fingerprint scan lines ROW960to ROW1056. The number of the scan signals are disclosed for example, and the invention is not limited thereto. Responsive to the scan signals STV5to STV7, the scan circuits201and/or203start to scan the fingerprint sensing zone406from the fingerprint scan lines ROW960to ROW1056. The scan circuits201and/or203may complete the scan operation based on the scan signals STV5and STV7.

FIG.11,FIG.12andFIG.13are schematic diagrams illustrating a remapping operation according to an embodiment of the invention. Referring toFIG.11toFIG.13, the fingerprint sensing circuit116generates the fingerprint image FPI_7according to the fingerprint sensing signal S3by a remapping operation. The converter circuit163may be designed to have 200 fingerprint sensing channels, and the number of the fingerprint sensing lines is 1000. The number of the fingerprint sensing lines and the number of the fingerprint sensing channels are disclosed for example, and the invention is not limited thereto.

In the present embodiment, the digital circuit161selects the fingerprint sensing lines RX50to RX249for fingerprint sensing, and the fingerprint sensing lines RX50and RX249are selected to be boundaries of the fingerprint sensing zone. Fingerprint sensing zones of the display panel120are not determined for each of the fingerprint sensing lines RX1to RX1000in advance. The fingerprint sensing signal S3carried on the fingerprint sensing lines RX50to RX249are read out by the converter circuit163at a time. The converter circuit163receives the fingerprint sensing signal S3from the fingerprint sensing lines RX50to RX249in a single-turn receiving manner. That is to say, the converter circuit163receives the fingerprint sensing signal S3from all of the selected fingerprint sensing lines RX50to RX249at once during the same fingerprint sensing phase. After signal conversion operation, the converter circuit163transmits the fingerprint sensing signal S3as depicted inFIG.12from the fingerprint sensing channels CH1to CH200to the digital circuit161.

In the present embodiment, the first part FPI_71of the fingerprint image FPI_7is sensed via the fingerprint sensors connected to the fingerprint sensing lines RX50to RX200and transmitted to the fingerprint sensing channels CH50to CH200. The second part FPI_72of the fingerprint image FPI_7is sensed via the fingerprint sensors connected to the fingerprint sensing lines RX201to RX249and transmitted to the fingerprint sensing channels CH1to CH49. The fingerprint sensing circuit116generates the fingerprint image FPI_7according to the fingerprint sensing signal S3by the remapping operation as depicted inFIG.13. The second part FPI_72is moved from the left side of the first part FPI_71to the right side, such that the remapped fingerprint image FPI_7is generated.

FIG.14andFIG.15are schematic diagrams illustrating display panels operating for sensing multiple fingerprint images according to different embodiments of the invention. Referring toFIG.14andFIG.15, the electronic circuit110may drive and control the display panel120to sense multiple fingerprint images FPI_1and FPI_2on the display panel120at the same time. The fingerprint images FPI_1and FPI_2may be located in different rows as shown inFIG.14, and the fingerprint images FPI_1and FPI_2may be located in the same rows as shown inFIG.15.

InFIG.14, the touch controller141informs the fingerprint sensing circuit116to sense the fingerprint images FPI_1and FPI_2via different parts of the fingerprint scan lines GSL. The fingerprint sensing circuit116receives the fingerprint sensing signal from all of the selected fingerprint sensing lines corresponding to the fingerprint images FPI_1and FPI_2at once during the same fingerprint sensing phase.

InFIG.15, the touch controller141informs the fingerprint sensing circuit116to sense the fingerprint images FPI_1and FPI_2via the same part of the fingerprint scan lines GSL. The fingerprint sensing circuit116receives the fingerprint sensing signal from all of the selected fingerprint sensing lines corresponding to the fingerprint images FPI_1and FPI_2at once during the same fingerprint sensing phase.

FIG.16is a schematic diagram illustrating converter circuit of the fingerprint sensing circuit configured to sense multiple fingerprint images according to an embodiment of the invention. For sensing multiple fingerprint images FPI_1and FPI_2, the converter circuit163may be designed to have N fingerprint sensing channels to receive and process the corresponding fingerprint sensing signal.

InFIG.16, the N fingerprint sensing channels are grouped into two parts CHP1and CHP2. Each part includes part of the fingerprint sensing channels to receive and process the corresponding fingerprint sensing signal. For example, if N is an even number, the fingerprint sensing circuit116may select the fingerprint sensing lines RX(n+1) to RX(n+N/2) to sense the fingerprint image FPI_1, and the fingerprint sensing lines RX(n+1) and RX(n+N/2) are selected to be boundaries of the fingerprint sensing zone. The fingerprint sensing signal corresponding to the fingerprint image FPI_1is transmitted to the first part CHP1with N/2 fingerprint sensing channels. On the other hand, the fingerprint sensing circuit116selects the fingerprint sensing lines RX(m+1) to RX(m+N/2) to sense the fingerprint image FPI_2, and the fingerprint sensing lines RX(m+1) and RX(m+N/2) are selected to be boundaries of the fingerprint sensing zone. The fingerprint sensing signal corresponding to the fingerprint image FPI_2is transmitted to the second part CHP2with N/2 fingerprint sensing channels. The fingerprint sensing signals carried on the selected part of fingerprint sensing lines RX(n+1) to RX(n+N/2) and RX(m+1) to RX(m+N/2) may be read out by the converter circuit163at a time. In an embodiment, the numbers of the fingerprint sensing channels of the two parts CHP1and CHP2are not necessary to be equal. Also, the total number of the fingerprint sensing channels of CHP1and CHP2can be smaller than or equal to N.

FIG.17is a schematic diagram illustrating control of the scan circuit configured to sense multiple fingerprint images according to an embodiment of the invention. Referring toFIG.17, the electronic circuit110controls the display panel120to sense multiple fingerprint images FPI_1and FPI_2. The electronic circuit110determines the coordinates of the touch areas TSA1and TSA2corresponding to the fingerprint images FPI_1and FPI_2. The fingerprint sensing zones401and402are respectively defined by the touch areas TSA1and TSA2. If the multiple fingerprint images FPI_1and FPI_2are not overlapped in the X direction, the electronic circuit110can control the scan circuits201and/or203to scan the fingerprint sensing zones401and402during the same fingerprint sensing phase in the Y direction. The fingerprint sensing zones401and402may be simultaneously scanned to reduce sensing time.

In summary, in the embodiments of the invention, fingerprint sensing zones of the display panel are not determined for each of the fingerprint sensing lines in advance, and the touch area defines the fingerprint sensing zone for covering a fingerprint image. A part of the fingerprint sensing lines and a part of the fingerprint scan lines are selected for fingerprint sensing operation according to the touch area. A part of switches corresponding to the part of fingerprint sensing lines is turned on to couple the part of fingerprint sensing lines to the fingerprint sensing channels. A part of the fingerprint sensing lines collocated with the touch area on the display panel is selected among a plurality of the fingerprint sensing lines arranged all over the display panel. The selected fingerprint sensing lines may flexibly form a single fingerprint sensing zone having a range determined by the touch area, and fingerprint sensing signals carried on the selected fingerprint sensing lines may be read out at a time, such that only a single-turn receiving of fingerprint sensing signals in fingerprint sensing channels is required for sensing one horizontal line of the fingerprint image. The time for fingerprint sensing is reduced. Therefore, the process for fingerprint sensing and identification is more efficient, and users have good user experience.