Patent Publication Number: US-2023152916-A1

Title: Electronic device having fingerprint sensing function

Description:
TECHNICAL FIELD 
     The present invention relates to a device, and in particular to an electronic device having a fingerprint sensing function. 
     DESCRIPTION OF RELATED ART 
     In recent years, fingerprint recognition technology has been widely used in various electronic devices to provide various identity login or authentication functions. At present, the technical principles of conventional fingerprint recognition include optical, capacitive, thermal, ultrasonic, etc. In this regard, since a fingerprint sensor for the above manners is disposed in the electronic device, the fingerprint sensor usually needs to occupy a part of the device volume of the electronic device. The general fingerprint sensor may be, for example, disposed or externally mounted under the screen, the home button, the back of the body, etc. of the electronic device. In other words, the general fingerprint sensor increases the overall device volume or thickness of the electronic device, thereby causing an increase in the manufacturing cost of the electronic device. In view of this, solutions of several embodiments will be provided below. 
     SUMMARY 
     The present invention is directed to an electronic device that can provide a large-area fingerprint sensing function. 
     According to an embodiment of the present invention, an electronic device of the present invention includes a touch display panel and an integrated chip. The touch display panel includes a pixel array. The integrated chip is electrically connected to the pixel array. The integrated chip includes a fingerprint sensing circuit and a display driving circuit. The fingerprint sensing circuit and the display driving circuit are electrically connected to a plurality of display data lines and a sensing data line by means of the same pin. The display data lines are respectively electrically connected to a plurality of color sub-pixels of the pixel array. The sensing data line is electrically connected to a plurality of fingerprint sensing pixels of the pixel array. The color sub-pixels are a plurality of organic light emitting diode pixels. 
     Based on the above, the electronic device of the present invention can realize the full-screen fingerprint sensing function through forming the fingerprint sensing pixels in the pixel array of the touch display panel, and since the fingerprint sensing pixels are embedded in the touch display panel, the electronic device of the present invention can effectively reduce the functional module space required for fingerprint sensing, thereby reducing the overall device volume or thickness of the electronic device. 
     In order for the features and advantages of the present invention to be more comprehensible, the following specific embodiments are described in detail in conjunction with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic diagram of an electronic device according to an embodiment of the present invention. 
         FIG.  2    is a schematic circuit diagram of a part of a pixel array according to an embodiment of the present invention. 
         FIG.  3    is a schematic circuit diagram of an integrated chip and a switching circuit according to an embodiment of the present invention. 
         FIG.  4    is a schematic diagram of an internal functional circuit of an integrated chip according to an embodiment of the present invention. 
         FIG.  5    is a signal timing diagram of a plurality of signals for operating an integrated chip according to an embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE REFERENCE SIGNS 
       100 : electronic device; 
       110 : touch display panel; 
       120 : pixel array; 
       130 : integrated chip; 
       131 : fingerprint sensing circuit; 
       131 _ 1 : amplifier; 
       131 _ 2 : analog-to-digital converter; 
       131 _ 3 : digital processor; 
       132 : display driving circuit; 
       132 _ 1 : source amplifier; 
       132 _ 2 : timing control circuit; 
       133 : control circuit; 
       141 ,  142 ,  143 ,  144 ,  145 : demultiplexer; 
     D 1 -D 4 , D 6 : display data line; 
     D 5 : sensing data line; 
     DS: display driving signal; 
     G 1 , G 2 : gate line; 
     GS 1 : scanning signal; 
     FS: sensing signal; 
     M 1 -M_ 5 , S 1 , S 2 : switching signal; 
     N 1 : pin; 
     T 1 -T 7 : transistor; 
     t 0 -t 6 : time. 
     DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS 
     Reference will now be made in detail to the exemplary embodiments of the present invention, examples of which are illustrated in the drawings. Wherever possible, the same reference numerals are used in the drawings and the description to refer to the same or similar parts. 
       FIG.  1    is a schematic diagram of an electronic device according to an embodiment of the present invention. Referring to  FIG.  1   , an electronic device  100  includes a touch display panel  110 , a pixel array  120 , and an integrated chip (IC)  130 . The pixel array  120  is electrically connected to the integrated chip  130 . In the embodiment, the touch display panel  110  may include, for example, a glass substrate and a touch panel, wherein the pixel array  120  is formed on the glass substrate of an active area (AA) of the touch display panel  110 . The integrated chip  130  is formed in a peripheral area (PA) of the touch display panel  110 . In the embodiment, the integrated chip  130  includes a fingerprint sensing circuit  131  and a display driving circuit  132 . It should be noted that the touch display panel  110  of the embodiment may adopt an in-cell fingerprint, touch, and display panel structure. The integrated chip  130  may be a fingerprint, touch, and display driver integrated (FTDDI) chip. 
     In the embodiment, the integrated chip  130  may be electrically connected to a plurality of display pixels and a plurality of fingerprint sensing pixels in the pixel array  120  by means of the same pin, and the integrated chip  130  drives a display module of the touch display panel  110  and the touch display panel  110  in a time-sharing manner. In other words, the integrated chip  130  of the embodiment may drive the display module and a fingerprint sensing module in the touch display panel  110  through fewer pins, thereby effectively reducing the space occupied by the pins and wiring in the electronic device  100 . 
     In the embodiment, the electronic device  100  is, for example, a smart phone, a tablet computer, a game console, or other electronic products having a fingerprint recognition function. The touch display panel  110  may include, for example, an organic light emitting diode (OLED) display panel, so a plurality of color sub-pixels of a plurality of pixel units of the pixel array  120  are a plurality of organic light emitting diode pixel units. In detail, in the embodiment, the pixel units of the pixel array  120  may be composed of a plurality of first color sub-pixels, a plurality of second color sub-pixels, a plurality of third color sub-pixels, and a plurality of fingerprint sensing pixels. The first to third color sub-pixels may be, for example, red color sub-pixels, green color sub-pixels, and blue color sub-pixels, but the present invention is not limited thereto. In an embodiment, the pixel units of the pixel array  120  may further include a plurality of fourth color sub-pixels, wherein the fourth color sub-pixels may be, for example, white color sub-pixels, but the present invention is not limited thereto. It should be noted that in the embodiment, the color sub-pixels may be formed on a first semiconductor layer of the touch display panel  110 , and the fingerprint sensing pixels may be formed on a second semiconductor layer of the touch display panel  110 . 
       FIG.  2    is a schematic circuit diagram of a part of a pixel array according to an embodiment of the present invention. Referring to  FIG.  1    and  FIG.  2   , a pixel unit  120 P of  FIG.  2    is a configuration result of one pixel in the pixel array  120 . In the embodiment, the pixel unit  120 P includes a first color sub-pixel  121 , a second color sub-pixel  122 , a third color sub-pixel  123 , a fourth color sub-pixel  124 , and a fingerprint sensing pixel  125 . The first color sub-pixel  121 , the second color sub-pixel  122 , the third color sub-pixel  123 , the fourth color sub-pixel  124 , and the fingerprint sensing pixel  125  are electrically connected to a gate line G 1 . A gate line G 2  is used to electrically connect to the next column of pixel units, and so on. The first color sub-pixel  121  to the fourth color sub-pixel  124  are respectively electrically connected to display data lines D 1  to D 4 . The fingerprint sensing pixel  125  is electrically connected to a sensing data line D 5 . A display data line D 6  is used to electrically connect to the next row of sub-pixels, and so on. 
     In the embodiment, the gate line G 1  may be used to receive a scanning signal to turn on the first color sub-pixel  121 , the second color sub-pixel  122 , the third color sub-pixel  123 , the fourth color sub-pixel  124 , and the fingerprint sensing pixel  125 . In the embodiment, the display data lines D 1  to D 4  are used to transmit a plurality of display driving signals (display data) provided by the integrated chip  130  to the first color sub-pixel  121 , the second color sub-pixel  122 , the third color sub-pixel  123 , and the fourth color sub-pixel  124 , so that the first color sub-pixel  121 , the second color sub-pixel  122 , the third color sub-pixel  123 , and the fourth color sub-pixel  124  respectively provide a display function according to the corresponding display driving signals (display data). In the embodiment, the sensing data line D 5  is used to transmit a sensing signal of the fingerprint sensing pixel  125  to the integrated chip  130 , so that the integrated chip  130  may generate a corresponding fingerprint sensing image according to the sensing signal. The arrangement order of the color sub-pixels of the present invention is not limited to the above. Moreover, the placement location of the fingerprint sensing pixel  125  may also be set between any two color sub-pixels. 
       FIG.  3    is a schematic circuit diagram of an integrated chip and a switching circuit according to an embodiment of the present invention. Referring to  FIG.  1    to  FIG.  3   , the integrated chip  130  includes the fingerprint sensing circuit  131  and the display driving circuit  132 . In the embodiment, the fingerprint sensing circuit  131  and the display driving circuit  132  are electrically connected to one terminal of switch transistors T 1  to T 5  by means of a same pin N 1  (that is, forming a common pin), and the other terminals of the switch transistors T 1  to T 5  are electrically connected to the display data lines D 1  to D 4  and the sensing data line D 5 . Control terminals of the switch transistors T 1  to T 5  are respectively electrically connected to demultiplexers (DMUX)  141  to  145 . In the embodiment, the demultiplexers  141  to  145  output switching signals at different timings to the switch transistors T 1  to T 5  to receive signals from the color sub-pixels  121  to  124  or the fingerprint sensing pixel  125  during different periods. The demultiplexers  141  to  145  may be respectively composed of one or more transistors or switch circuits, and the demultiplexers  141  to  145  may form a demultiplexer circuit. 
     In the embodiment, the display data lines D 1  to D 4  and the sensing data line D 5  are electrically connected to a row pixel group of the pixel array  120 , wherein the row pixel group may include a plurality of pixel units  120 P as in the above embodiment of  FIG.  2    arranged in sequence along the data line. In other words, the fingerprint sensing circuit  131  and the display driving circuit  132  of the integrated chip  130  provide a plurality of data signals to a plurality of color sub-pixels in the row pixel group electrically connected to the display data lines D 1  to D 4  by means of the same pin N 1 , and receive sensing results of a plurality of fingerprint sensing pixels in the row pixel group through the sensing data line D 5 . However, in an embodiment, the pin N 1  may also be electrically connected to other row pixel groups in the pixel array  120 , or the integrated chip  130  may be electrically connected to other row pixel groups in the pixel array  120  by means of other pins similar to the pin N 1 . In addition, the timings of the switching signals, the display driving signals, and the sensing signal of the embodiment will be described in detail with reference to the embodiment of  FIG.  5    below. 
       FIG.  4    is a schematic diagram of an internal functional circuit of an integrated chip according to an embodiment of the present invention. Referring to  FIG.  4   , the integrated chip  130  includes the fingerprint sensing circuit  131 , the display driving circuit  132 , and a control circuit  133 . In the embodiment, the control circuit  133  is electrically connected between the pin N 1  and the fingerprint sensing circuit  131  by means of a first switching circuit, and is electrically connected between the pin N 1  and the display driving circuit  132  by means of a second switching circuit. The control circuit is used to alternately turn on the first switching circuit and the second switching circuit. In the embodiment, the first switching circuit may be a switch transistor T 6 , and the second switching circuit may be a switch transistor T 7 , but the present invention is not limited thereto. One terminal of the switch transistor T 6  is electrically connected to the pin N 1 , and one terminal of the switch transistor T 7  is electrically connected to the pin N 1  and one terminal of the switch transistor T 6 . Control terminals of the switch transistor T 6  and the switch transistor T 7  are electrically connected to the control circuit  133 . The control circuit  133  may output two switching signals Si and S 2  to the switch transistor T 6  and the switch transistor T 7  to control the switch transistor T 6  and the switch transistor T 7 . 
     In the embodiment, the fingerprint sensing circuit  131  includes an amplifier  131 _ 1 , an analog-to-digital converter  131 _ 2 , and a digital processor  131 _ 3 . An input terminal of the amplifier  131 _ 1  is electrically connected to the other terminal of the switch transistor T 6 . An input terminal of the analog-to-digital converter  131 _ 2  is electrically connected to an output terminal of the amplifier  131 _ 1 . The digital processor  131 _ 3  is electrically connected to an output terminal of the analog-to-digital converter  131 _ 2 . In the embodiment, the display driving circuit  132  includes a source amplifier  132 _ 1  and a timing control circuit  132 _ 2 . An input terminal of the source amplifier  132 _ 1  is electrically connected to the timing control circuit  132 _ 2 , and an output terminal of the source amplifier  132 _ 1  is electrically connected to the other terminal of the switch transistor T 7 . In the embodiment, the pin N 1  is electrically connected to the switch transistors T 1  to T 5  on one side opposite to the pin N 1 . The switch transistors T 1  to T 5  are electrically connected to the display data lines D 1  to D 4  and the sensing data line D 5 . 
     In the embodiment, the amplifier  131 _ 1  may receive the sensing signal and provide a sensing signal FS after signal amplification to the analog-to-digital converter  131 _ 2 . The analog-to-digital converter  131 _ 2  may provide a digital signal of a fingerprint sensing result to the digital processor  131 _ 3 , so that the digital processor  131 _ 3  may generate fingerprint sensing information, for example, generate a fingerprint sensing image, according to the digital signal provided by the analog-to-digital converter  131 _ 2 . In the embodiment, the timing control circuit  132 _ 2  of the display driving circuit  132  may provide the timing control signal to the source amplifier  132 _ 1 , so that the source amplifier  132 _ 1  outputs a display driving signal DS according to the designed display timing. 
       FIG.  5    is a signal timing diagram of a plurality of signals for operating an integrated chip according to an embodiment of the present invention. Referring to  FIG.  2    to  FIG.  5   , a time t 0  to a time t 6  are a driving period of the pixel unit  120 P (or the driving period of one row pixel group), wherein the driving period includes a display driving period and a fingerprint sensing period, and the display driving period and the fingerprint sensing period do not overlap. For example, the display driving period is from the time t 0  to the time t 5 . The fingerprint sensing period is from the time t 5  to the time t 6 . In an embodiment, the color sub-pixels  121  to  124  and the fingerprint sensing pixel  125  of the pixel unit  120 P receive a scanning signal GS 1  by means of the gate line G 1 , and are turned on from the time t 0  to the time t 5 . In the embodiment, the switch transistor T 7  receives the switching signal S 1 , and the switch transistor T 6  receives the switching signal S 2 . The switch transistors T 1  to T 5  respectively receive switching signals M_ 1  to M_ 5  respectively provided by the demultiplexers  141  to  145 . 
     In the embodiment, the switch transistor T 6  is turned off during the display driving period (the time t 0  to the time t 5 ), and the switch transistor T 7  is turned on during the display driving period (the time t 0  to the time t 5 ). During the display driving period, the display driving period includes four sub-display driving periods, wherein the four sub-display driving periods are respectively from the time t 1  to the time t 2 , from the time t 2  to the time t 3 , from the time t 3  to the time t 4 , and from the time t 4  to the time t 5 . The switch transistors T 1  to T 4  respectively receive the switching signals M_ 1  to M_ 4  during the four sub-display driving periods and are turned on during different periods, and the switch transistor T 5  is turned off. Signal waveforms of the switching signals M_ 1  to M_ 4  do not overlap in time. Therefore, during the four sub-display driving periods, the display driving circuit  132  respectively outputs first to fourth display driving signals (square waveforms of the display driving signal DS during the four sub-display driving periods as shown in  FIG.  5   ) to the display data lines D 1  to D 4  by means of the pin N 1  during different periods. 
     In this regard, during the display driving period, the display driving circuit  132  may output the display driving signal DS to the color sub-pixels  121  to  124  by means of the display data lines D 1  to D 4 , so that the pixel unit  120 P performs the display function. However, it should be noted that the display driving signal DS of  FIG.  5    only represents the timing relationship of the signal waveforms, instead of the actual signal waveforms. In this regard, the voltage level or the potential level of the display data of the display driving signal DS may be determined by different display effects or individual sub-pixel types, which is not limited by the present invention. 
     In the embodiment, the switch transistor T 5  is turned on during the fingerprint sensing period (the time t 5  to the time t 6 ), and the switch transistor T 6  is turned off during the fingerprint sensing period (the time t 5  to the time t 6 ). During the fingerprint sensing period, the switch transistors T 1  to T 4  are turned off, and the switch transistor T 5  is turned on. The signal waveform of the switching signal M_ 5  and the signal waveforms of the switching signals M_ 1  to M_ 4  do not overlap. Therefore, the fingerprint sensing circuit  131  may receive the sensing signal FS from the fingerprint sensing pixel  125  by means of the sensing data line D 5 , so that the pixel unit  120 P performs the fingerprint sensing function. However, it should be noted that the sensing signal FS of  FIG.  5    only represents the timing relationship of the signal waveforms, instead of the actual signal waveforms. In this regard, the voltage level or the potential level of the sensing data of the sensing signal FS may be determined by different sensing results. 
     In summary, the electronic device of the present invention implements an in-cell fingerprint, touch, and display panel structure, and uses the fingerprint, touch, and display driver integrated chip to drive the touch display panel embedded with the fingerprint sensing pixels. Therefore, the electronic device of the present invention can save the space occupied by the driving circuit in the peripheral area of the panel. Alternatively, the integrated chip of the present invention may transmit the display driving signal and the sensing signal by means of the same pin, which can effectively save the space occupied by the pins and wiring in the peripheral area of the panel. 
     Finally, it should be noted that the above embodiments are only used to illustrate, but not to limit, the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, persons skilled in the art should understand that the technical solutions described in the above embodiments can still be modified or some or all of the technical features thereof can be equivalently replaced. However, the modifications or replacements 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.