Patent Publication Number: US-2023152918-A1

Title: Display panel and operation method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of U.S. provisional application Ser. No. 63/278,501, filed on Nov. 12, 2021. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
    
    
     BACKGROUND 
     Technical Field 
     The disclosure relates to an electronic device; more particularly, the disclosure relates to a display panel and an operation method thereof. 
     Description of Related Art 
     After a capacitive active stylus is paired with a display device, a user may operate the active stylus to write and draw on a display panel of the display device. In general, the display panel is divided into a display area and a frame area or a border area. The frame area is configured with a light shielding layer, so that the frame area does not have a display function. In addition, the frame area does not have an active stylus detection function nor a touch detection function. The display area is configured to display an image. Besides, the display area has the active stylus detection function and the touch detection function. During a touch sensing period, the display area emits an uplink signal and/or receives a downlink signal emitted by the active stylus, so as to perform an active stylus touch detection operation. For instance, a sensing electrode in the display area of the display panel may emit the uplink signal to the active stylus for pairing communications. After the pairing operation succeeds, the active stylus may emit the downlink signal to the display panel for reporting/positioning. 
     In order to reduce power consumption of the active stylus, the active stylus generally starts to send a downlink signal to the display panel after the active stylus receives the uplink signal from the display panel. However, such mechanism may lead to issues in some usage scenarios. For instance, when the active stylus draws/moves toward the center from the edge (the frame area) of the display panel, the active stylus in the frame area of the display panel does not receive the uplink signal emitted by the display area of the display panel, and, the active stylus receives the upland signal and starts to perform the pairing operation after entering the display area of the display panel. Therefore, the active stylus is unable to output the downlink signal at the initial stage of entering the display area (a period during which the pairing operation is not yet completed or a period of wakening the active stylus). As a result, the active stylus is unable to write on the edge of the display area when the active stylus draws a line from the frame area to the center. That is, the writing trace of the active stylus is interrupted at the edge of the display area. 
     The information disclosed in this BACKGROUND section merely serves to enhance understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Further, the information disclosed in the BACKGROUND section does not mean that one or more problems to be resolved by one or more embodiments of the disclosure was acknowledged by a person of ordinary skill in the art. 
     SUMMARY 
     The disclosure provides a display panel and an operation method thereof to instantly emit an uplink signal to perform an active stylus touch detection operation. 
     In an embodiment of the disclosure, the display panel includes a display area and a frame area. The display area is configured to display an image. During a touch sensing period, the display area and the frame area emit an uplink signal to perform an active stylus touch detection operation. The frame area is configured to emit the uplink signal during the touch sensing period to perform the active stylus touch detection operation. 
     In an embodiment of the disclosure, the operation method includes displaying an image by a display area and emitting, by the display area and a frame area, an uplink signal during a touch sensing period to perform an active stylus touch detection operation. 
     In view of the above, according to one or more embodiments of the disclosure, the frame area of the display panel may emit the uplink signal to the active stylus during the touch sensing period. While the active stylus draws a line/moves toward a center of the display panel from the frame area of the display panel, the active stylus in the frame area is able to receive the uplink signal emitted by the frame area, and then the active stylus in the display area may continue to receive the uplink signal emitted by the display area. Therefore, before the active stylus enters the display area of the display panel, the active stylus may perform the active stylus touch detection operation (e.g., performing a pairing operation) in advance based on the uplink signal emitted by the frame area. The display panel may instantly emit the uplink signal to perform the active stylus touch detection operation. As such, the active stylus is ready to emit a downlink signal to the display panel before entering the display area, and thus when the active stylus draws a line from the frame area toward the center, the active stylus is able to write on the edge of the display area and on other locations. 
     To make the above more comprehensible, several embodiments accompanied with drawings are described in detail as follows. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the disclosure and, together with the description, serve to explain the principles provided in the disclosure. 
         FIG.  1    is a schematic circuit block view of a display device according to an embodiment of the disclosure. 
         FIG.  2    is a schematic flowchart of an operation method of a display panel according to an embodiment of the disclosure. 
         FIG.  3    and  FIG.  4    are schematic cross-sectional views of a display panel according to an embodiment of the disclosure. 
         FIG.  5    is a schematic top view of a frame area of a display panel according to an embodiment of the disclosure. 
         FIG.  6    is a schematic cross-sectional view of a frame area of a display panel according to an embodiment of the disclosure. 
         FIG.  7    is a schematic cross-sectional view of a frame area of a display panel according to another embodiment of the disclosure. 
         FIG.  8    is a schematic cross-sectional view of a frame area of a display panel according to still another embodiment of the disclosure. 
         FIG.  9    is a schematic top view of a frame area of a display panel according to an embodiment of the disclosure. 
         FIG.  10 A  and  FIG.  10 B  are schematic circuit diagrams of a gate driving circuit according to an embodiment of the disclosure. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     The terminology “coupled” (or connected) may refer to any direct or indirect connection means. For instance, if it is described in the disclosure that a first device is coupled (or connected) to a second device, it should be interpreted that the first device can be directly connected to the second device, or the first device can be indirectly connected to the second device through other devices or some connection means. The terminologies such as “first”, “second”, etc. may be used to name elements or distinguish the elements in different embodiments or scope, but the upper or lower limit of the number of the elements should not be limited by these terminologies, nor should the order of the elements be limited. Besides, wherever possible, the same reference numbers marking the elements/components/steps in the accompanying drawings and following embodiments represent the same or similar elements/components/steps, and the descriptions of the elements/components/steps marked by the same reference numbers in one embodiment may be referred by the relevant descriptions of the elements/components/steps in other embodiments. 
     The following embodiments are provided to explain an improved panel architecture. According to these embodiments, a signal path is placed in a frame area of a display panel to provide an uplink signal to an active stylus. Therefore, the active stylus is able to obtain the uplink signal in the frame area of the display panel (rather than a display area) in advance and complete a pairing operation. According to these embodiments, signal quality of the uplink signal in the frame area may be improved without changing the size of electrodes in the display area, thereby resolving the issue of interrupted writing on the edge of the display panel. 
       FIG.  1    is a schematic circuit block view of a display device  100  according to an embodiment of the disclosure. The display device  100  shown in  FIG.  1    includes a driving circuit  110  and a display panel  120 . The driving circuit  110  is able to drive the display panel  120  to display an image in a display area  122  of the display panel  120 . In some embodiments, the display area  122  further has a touch detection function. The driving circuit  110  may detect a touch event occurring in the display area  122  through a touch electrode in the display area  122 . In the embodiment shown in  FIG.  1   , the display area  122  further has an active stylus touch detection function. The driving circuit  110  may transmit an uplink signal to the active stylus  10  through electrodes in the display area  122  and receive a downlink signal emitted by the active stylus  10  through the electrodes in the display area  122 . 
     In addition, in the embodiment shown in  FIG.  1   , the driving circuit  110  may further transmit the uplink signal to the active stylus  10  through a frame area (or a border area)  121  of the display panel  120 . The frame area  121  is adjacent to a frame (not shown) of the display panel  120  and is located outside the display area  122 . The frame of the display panel  120  is configured to fix the display panel  120  to a specific location within the display device  100 . Generally, the frame area  121  is configured with a light shielding layer, so that the frame area  121  does not have a display function. According to the actual design, the light shielding layer may include a black matrix layer, an opaque printing ink layer, or any other opaque non-conductive material layer. 
       FIG.  2    is a schematic flowchart of an operation method of the display panel  120  according to an embodiment of the disclosure. With reference to  FIG.  1    and  FIG.  2   , in step  5210 , the driving circuit  110  may drive the display panel  120 , so that the display area  122  of the display panel  120  displays the image. In step  5220 , the frame area  121  and the display area  122  of the display panel  120  emit the uplink signal to the active stylus  10  during a touch sensing period to perform an active stylus touch detection operation. Before the active stylus  10  enters the display area  122 , the active stylus  10  may perform the active stylus touch detection operation (e.g., performing a pairing operation) in advance based on the uplink signal emitted by the frame area  121 . Thereby, the active stylus  10  is ready to emit the downlink signal to the display panel  120  before entering the display area  122 . 
       FIG.  3    is a schematic cross-sectional view of the display panel  120  according to an embodiment of the disclosure. The descriptions of the active stylus  10 , the display panel  120 , the frame area  121 , and the display area  122  as illustrated in  FIG.  3    may be referred to as the descriptions of the active stylus  10 , the display panel  120 , the frame area  121 , and the display area  122  illustrated in  FIG.  1    and thus will not be repeated. When the active stylus  10  moves to the top of the frame area  121  of the display panel  120 , the uplink signal may be emitted through a signal path in the frame area  121  during the touch sensing period, so as to perform the active stylus touch detection operation. According to the actual design, the signal path in the frame area  121  may be arranged in a metal layer M 0  (not shown), a metal layer M 1  (not shown), a metal layer M 2  (not shown), a metal layer M 3  (not shown), an indium tin oxide (ITO) layer (not shown), and/or other conductive layers of the display panel  120 . While the active stylus  10  is drawing a line/moving toward the display area  122  from the frame area  121 , the active stylus  10  in the frame area  121  may receive the uplink signal emitted by the frame area  121 . The uplink signal emitted by the frame area  121  may trigger the active stylus  10  to emit the downlink signal, and the display area  122  may receive the downlink signal emitted by the active stylus  10  to perform a positioning operation on the active stylus  10 . 
       FIG.  4    is a schematic cross-sectional view of the display panel  120  according to an embodiment of the disclosure. The descriptions of the active stylus  10 , the display panel  120 , the frame area  121 , and the display area  122  as illustrated in  FIG.  4    may be referred to as the descriptions of the active stylus  10 , the display panel  120 , the frame area  121 , and the display area  122  illustrated in  FIG.  1    and thus will not be repeated. When the active stylus  10  moves to the top of the display area  122  of the display panel  120 , the electrodes in the display area  122  may transmit the uplink signal to the active stylus  10  during the touch sensing period and receive the downlink signal emitted by the active stylus  10  to perform the active stylus touch detection operation. 
     The uplink signal emitted by the frame area  121  and the display area  122  may trigger the active stylus  10  to emit the downlink signal, and the display area  122  may receive the downlink signal emitted by the active stylus  10  to perform the positioning operation on the active stylus  10 . While the active stylus  10  is drawing a line/moving toward the display area  122  from the frame area  121 , the active stylus  10  in the frame area  121  may receive the uplink signal emitted by the frame area  121 , and then the active stylus  10  in the display area  122  may continue to receive the uplink signal emitted by the display area  122 . Therefore, before the active stylus  10  enters the display area  122 , the active stylus  10  may perform the active stylus touch detection operation (e.g., a pairing operation) in advance based on the uplink signal emitted by the frame area  121 . The display panel  120  may instantly emit the uplink signal to perform the active stylus touch detection operation. Thereby, the active stylus  10  is ready to emit the downlink signal to the display panel  120  before entering the display area  122 . Accordingly, when the active stylus  10  draws a line toward the display area  122  from the frame area  121 , the active stylus  10  may write on the edge of the display area  122  and on other locations. 
       FIG.  5    is a schematic top view of the frame area  121  of the display panel  120  according to an embodiment of the disclosure.  FIG.  5    shows a partial enlarged view of the frame area  121 . In the embodiment shown in  FIG.  5   , an electrostatic discharge (ESD) protection conductive wire  510  and an uplink signal wire  520  are arranged in the frame area  121 . The ESD wire  510  is configured for ESD. The ESD wire  510  and the uplink signal wire  520  are arranged in the same conductive layer of the display panel  120 . In some embodiments, the ESD wire  510  and the uplink signal wire  520  are arranged in the metal layer M 1  or M 2  of the display panel  120 . The uplink signal wire  520  is configured to be coupled to a touch detection circuit (e.g., the driving circuit  110 ) to receive the uplink signal. The touch detection circuit may emit the uplink signal to the active stylus  10  through the uplink signal wire  520  in the frame area  121  during the touch sensing period to perform the active stylus touch detection operation. 
       FIG.  6    is a schematic cross-sectional view of the frame area  121  of the display panel  120  according to an embodiment of the disclosure. The display panel  120  shown in  FIG.  6    has a lower substrate SUB 6 . A thin film transistor (TFT) of the display panel  120  may be arranged on the lower substrate SUB 6 . When the display panel  120  is a non-self-luminous panel, the lower substrate SUB 6  may be a transparent substrate, so that the back light may penetrate the display panel  120 . 
     In the embodiment shown in  FIG.  6   , an uplink signal wire  610  and a gate driving circuit  620 , which is alternatively referred to as a gate driver-on-array (GOA), are arranged in the frame area  121 . The descriptions of the uplink signal wire  610  shown in  FIG.  6    may be referred to as and deduced from the descriptions of to the uplink signal wire  520  shown in  FIG.  5    and thus will not be repeated here. The gate driving circuit  620  may drive a plurality of scan lines (not shown) in the display area  122  during a display driving period to display the image. In the embodiment shown in  FIG.  6   , the gate driving circuit  620  and the uplink signal wire  610  are arranged in different conductive layers of the display panel  120 . For instance, the frame area  121  is configured with a light shielding layer, so that the frame area  121  does not have the display function. The uplink signal wire  610  may serve as the light shielding layer. 
       FIG.  7    is a schematic cross-sectional view of the frame area  121  of the display panel  120  according to another embodiment of the disclosure. The display panel  120  shown in  FIG.  7    has an upper substrate SUB 71  and a lower substrate SUB 72 . The upper substrate SUB 71  may be a transparent substrate, such as a glass substrate. The TFT of the display panel  120  may be arranged on the lower substrate SUB 72 . When the display panel  120  is a non-self-luminous panel, the lower substrate SUB 72  may be a transparent substrate, so that the back light may penetrate the display panel  120 . 
     In the embodiment shown in  FIG.  7   , a black matrix layer BM 7  (a light shielding layer) of the upper substrate SUB 71  is arranged in the frame area  121 , so that the frame area  121  does not have the display function. The frame area  121  is further configured with an uplink signal wire  710 . The descriptions of the uplink signal wire  710  shown in  FIG.  7    may be referred to as and deduced from the descriptions of the uplink signal wire  520  shown in  FIG.  5    and thus will not be repeated herein. The uplink signal wire  710  is arranged on a lower side of the black matrix layer BM 7 . According to the actual design, in some embodiments, the uplink signal wire  710  may be a silver paste printed circuit or an adhesive copper foil circuit. The uplink signal wire  710  may be electrically connected to a touch detection circuit (e.g., the driving circuit  110 ) through a conductive material  720  to receive the uplink signal. 
       FIG.  8    is a schematic cross-sectional view of the frame area  121  of the display panel  120  according to still another embodiment of the disclosure. The display panel  120  shown in  FIG.  8    has an upper substrate SUB 81  and a lower substrate SUB 82 . The upper substrate SUB 81  may be a transparent substrate, such as a glass substrate. The TFT of the display panel  120  may be arranged on the lower substrate SUB 82 . When the display panel  120  is a non-self-luminous panel, the lower substrate SUB 82  may be a transparent substrate, so that the back light may penetrate the display panel  120 . 
     In the embodiment shown in  FIG.  8   , the frame area  121  is further configured with an uplink signal wire  810 . The descriptions of the uplink signal wire  810  shown in  FIG.  8    may be referred to as and deduced from the descriptions of the uplink signal wire  520  shown in  FIG.  5    and thus will not be repeated herein. The uplink signal wire  810  may serve as a black matrix layer BM 8  (a light shielding layer) of the upper substrate SUB 81 , so that the frame area  121  does not have the display function. The black matrix layer BM 8  in the frame area  121  may be made of a conductive ink, so that the black matrix layer BM 8  has the characteristics of the uplink signal wire  810 . In the embodiment shown in  FIG.  8   , the upper substrate SUB 81  is coated with the conductive black matrix layer BM 8  and does not need to be coated with other additional conductive layers. The uplink signal wire  810  may be electrically connected to a touch detection circuit (e.g., the driving circuit  110 ) through a conductive material to receive the uplink signal. 
       FIG.  9    is a schematic top view of the frame area  121  of the display panel  120  according to an embodiment of the disclosure.  FIG.  9    shows a partial enlarged view of the frame area  121 . In the embodiment shown in  FIG.  9   , the frame area  121  is configured with a gate driving circuit (or referred to as a GOA)  910 . The gate driving circuit  910  may drive a plurality of scan lines (not shown) in the display area  122  during a display driving period to display the image. 
       FIG.  10 A  and  FIG.  10 B  are schematic circuit diagrams of the gate driving circuit  910  according to an embodiment of the disclosure.  FIG.  10 A  shows a switching status of the gate driving circuit  910  which operates during a display driving period, and  FIG.  10 B  shows a switching status of the gate driving circuit  910  which operates during a touch sensing period. In the embodiment shown in  FIG.  10 A  and  FIG.  10 B , the frame area  121  includes the gate driving circuit  910 , a switch SW 101 , a switch SW 102 , a switch SW 103 , a switch SW 104 , a switch SW 105 , and a switch SW 106 . The descriptions of the gate driving circuit  910  shown in  FIG.  10 A and  10 B  may be referred to as and deduced from the descriptions of the gate driving circuit  910  shown in  FIG.  9   . VGH and VGL shown in  FIG.  10 A  and  FIG.  10 B  respectively represent voltage sources of different levels. 
     A first terminal of the switch SW 101  is coupled to one clock terminal of the gate driving circuit  910 , and a first terminal of the switch SW 102  is coupled to the other clock terminal of gate driving circuit  910 . A first terminal of a clock wire CKW 101  is coupled to a second terminal of the switch SW 101 , and the first terminal of the clock wire CKW 102  is coupled to a second terminal of the switch SW 102 . A first terminal of the switch SW 103  is coupled to a second terminal of the clock wire CKW 101 . A second terminal of the switch SW 103  is configured to be coupled to a gate clock source (not shown) to receive a clock signal CLK_ 1 . A first terminal of the switch SW 104  is coupled to the second terminal of the clock wire CKW 101 . A second terminal of the switch SW 104  and a second terminal of the switch SW 105  are configured to be coupled to a touch detection circuit (e.g., the driving circuit  110 ) to receive an uplink signal UL. A first terminal of the switch SW 105  and a first terminal of switch SW 106  are coupled to the second terminal of the clock wire CKW 102 . A second terminal of the switch SW 106  is configured to be coupled to the gate clock source (not shown) to receive a clock signal CLK_ 2 . 
     During the display driving period shown in  FIG.  10 A , the switch SW 101 , the switch SW 102 , the switch SW 103 , and the switch SW 106  are turned on, while the switch SW 104  and the switch SW 105  are turned off. Therefore, the clock signal CLK_ 1  of the gate clock source may be transmitted to the one clock terminal of the gate driving circuit  910  through the switch SW 103 , the clock wire CKW 101 , and the switch SW 101 , and the clock signal CLK_ 2  of the gate clock source may be transmitted to the other clock terminal of the gate driving circuit  910  through the switch SW 106 , the clock wire CKW 102 , and the switch SW 102 . 
     During the touch sensing period shown in  FIG.  10 B , the switch SW 101 , the switch SW 102 , the switch SW 103 , and the switch SW 106  are turned off, while the switch SW 104  and the switch SW 105  are turned on. Therefore, the clock wire CKW 101  and the clock wire CKW 102  may serve as the uplink signal wire. At this time, the clock wire CKW 101  and the clock wire CKW 102  may emit the uplink signal UL to the active stylus  10  to perform the active stylus touch detection operation. 
     To sum up, the frame area  121  of the display panel  120  in one or more embodiments of the disclosure may emit the uplink signal UL to the active stylus  10  during the touch sensing period. While the active stylus  10  is drawing a line/moving toward the display area  122  from the frame area  121  of the display panel  120 , the active stylus  10  in the frame area  121  may receive the uplink signal UL emitted by the frame area  121 , and then the active stylus  10  in the display area  122  may continue to receive the uplink signal UL emitted by the display area  122 . Hence, before the active stylus  10  enters the display area  122  from the frame area  121 , the active stylus  10  may perform the active stylus touch detection operation (e.g., the pairing operation) in advance based on the uplink signal UL emitted by the frame area  121 . Thereby, the active stylus  10  is ready to emit the downlink signal to the display panel  120  before entering the display area  122 . As a result, when the active stylus  10  draws a line toward the display area  122  from the frame area  121 , the active stylus  10  may write on the edge of the display area  122  and on other locations. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure covers modifications and variations provided they fall within the scope of the following claims and their equivalents.