Patent Publication Number: US-2023152928-A1

Title: Touch sensor and display device including the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority under 35 U.S.C. § 119(a) to Korean patent application 10-2021-0158018, filed on Nov. 16, 2021 in the Korean Intellectual Property Office, the entire disclosure of which is herein incorporated by reference. 
     TECHNICAL FIELD 
     The present disclosure generally relates to a display device, and more particularly, to a display device including a touch sensor having multiple touch sensing areas. 
     DISCUSSION OF THE RELATED ART 
     Display devices are often configured as touch-screen display devices that include a display panel along with a touch sensor to register a touch of a user. 
     The touch sensor may be attached to one surface of a display panel, for example, a display surface of the display panel. Alternatively, the touch sensor may be integrally formed with the display panel. A user may input information by pressing or touching the touch sensor while viewing an image implemented on the display panel. 
     SUMMARY 
     A touch sensor includes first touch cells disposed in a first touch sensing area, the first touch cells each including a first touch pattern and a first dummy pattern that is disposed within a first dummy pattern area, and second touch cells disposed in a second touch sensing area, the second touch cells each including a second touch pattern and a second dummy pattern that is disposed within a second dummy pattern area. An area of the first dummy pattern area is greater than an area of the second dummy pattern area. 
     The first touch pattern may be disposed within a first touch pattern area, the second touch pattern may be disposed within a second touch pattern area, and an area of the first touch pattern area may be smaller than an area of the second touch pattern area. 
     The touch sensor may further include first sensing lines each including a first portion connected to a portion of the first touch cells and extended in a first direction in a non-sensing area, and second sensing lines each including a second portion connected to a portion of the second touch cells and extended in the first direction in the non-sensing area. 
     A thickness of the first portion may be greater than a thickness of the second portion. 
     A width of the first portion may be greater than a width of the second portion. 
     A size of the first dummy pattern area in the second touch sensing area may be gradually changed in the first direction. 
     The first touch sensing area may include first sub-touch sensing areas each including the first dummy pattern area. The second touch sensing area may include second sub-touch sensing areas each including the second dummy pattern area. The first sub-touch sensing areas and the second sub-touch sensing areas may be alternately disposed in the first direction. 
     Each of the first touch pattern, the second touch pattern, the first dummy pattern, and the second dummy pattern may include a mesh pattern formed with fine conductive lines. 
     A thickness of the fine conductive lines of the first touch pattern may be greater than a thickness of the fine conductive lines of the second touch pattern. 
     A width of the fine conductive lines of the first touch pattern may be greater than a width of the fine conductive lines of the second touch pattern. 
     A thickness of the fine conductive lines of the first dummy pattern may be greater than a thickness of the fine conductive lines of the second dummy pattern. 
     A width of the fine conductive lines of the first dummy pattern may be greater than a width of the fine conductive lines of the second dummy pattern. 
     The touch sensor may further include a sensor driver configured to determine a touch position, based on a difference between raw data provided from the first touch cells and the second touch cells and a value of a baseline corresponding to a base capacitance of the first and second touch cells, and update the value of the baseline, based on a change in the raw data in a state in which there is no touch input. 
     A display device includes a display panel including a display area having pixels, and a touch sensor including a first touch sensing area and a second touch sensing area. The touch sensor is configured to sense a touch input. The first touch sensing area and the second touch sensing area each overlap the display area. The touch sensor incudes first touch cells disposed in the first touch sensing area, the first touch cells each including a first touch pattern and a first dummy pattern disposed within a first dummy pattern area, and second touch cells disposed in the second touch sensing area, the second touch cells each including a second touch pattern and a second dummy pattern disposed within a second dummy pattern area. An area of the first dummy pattern area is greater than an area of the second dummy pattern area. 
     The first touch pattern may be disposed within a first touch pattern area. The second touch pattern may be disposed within a second touch pattern area. An area of the first touch pattern area may be smaller than an area of the second touch pattern area. 
     The touch sensor may further include first sensing lines each including a first portion connected to a portion of the first touch cells and extended in a first direction in a non-sensing area, and second sensing lines each including a second portion connected to a portion of the second touch cells and extended in the first direction in the non-sensing area. A width of the first portion may be greater than a width of the second portion. 
     The touch sensor may further include first sensing lines each including a first portion connected to a portion of the first touch cells and extended in a first direction in a non-sensing area, and second sensing lines each including a second portion connected to a portion of the second touch cells and extended in the first direction in the non-sensing area. A thickness of the first portion may be greater than a thickness of the second portion. 
     The display device may further include a fingerprint sensor overlapping the second touch sensing area. 
     The display panel may display a keypad image overlapping the second touch sensing area. 
     A display device includes a display panel including a display area having pixels, and a touch sensor including a first touch sensing area and a second touch sensing area. The touch sensor is configured to sense a touch input. The first touch sensing area and the second touch sensing area each overlap the display area. The touch sensor includes first touch cells disposed in a first touch sensing area, second touch cells disposed in a second touch sensing area, first sensing lines each including a first portion connected to a portion of the first touch cells and extended in a first direction in a non-sensing area, and second sensing lines each including a second portion connected to a portion of the second touch cells and extended in the first direction in the non-sensing area. A width and/or a thickness of the first portion is greater than a width and/or a thickness of the second portion, respectively. 
     Each of the first touch cells may include a first touch pattern and a first dummy pattern, and each of the second touch cells may include a second touch pattern and a second dummy pattern. 
     Each of the first touch pattern and the second touch pattern may include a mesh pattern formed with fine conductive lines. A width and/or a thickness of the fine conductive lines of the first touch pattern may be greater than a width and/or a thickness of the fine conductive lines of the second touch pattern, respectively. 
     The display device may further include a fingerprint sensor overlapping the second touch sensing area. The display panel may display a keypad image overlapping the second touch sensing area. 
     The touch sensor may further include a sensor driver configured to determine a touch position, based on a difference between raw data provided from the first touch cells and the second touch cells and a value of a baseline corresponding to a base capacitance of the first and second touch cells, and update the value of the baseline, based on a change in the raw data in a state in which there is no touch input. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of the present disclosure and many of the attendant aspects thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
         FIG.  1    is a diagram illustrating a display device in accordance with embodiments of the present disclosure; 
         FIG.  2    is a cross-sectional view illustrating an example of a portion of a display area of the display device shown in  FIG.  1   ; 
         FIGS.  3 A to  3 D  are plan views illustrating examples of a touch sensor included in the display device shown in  FIG.  1   ; 
         FIG.  4    is a plan view illustrating an example of sensing cells included in the touch sensor shown in  FIG.  3 A ; 
         FIG.  5    is a diagram illustrating an example of updating a baseline according to a change in raw data corresponding to a touch sensing signal; 
         FIG.  6    is a diagram illustrating an example of a change in raw data according to a touch input in a low temperature condition and a baseline updated according the change in raw data; 
         FIG.  7    is a plan view illustrating an example of a first touch cell and a second touch cell, which are included in the touch sensor shown in  FIG.  3 A ; 
         FIG.  8    is a plan view illustrating an example of the first touch cell and the second touch cell, which are included in the touch sensor shown in  FIG.  3 A ; 
         FIG.  9    is a schematic diagram illustrating an example of the touch sensor shown in  FIG.  3 A ; 
         FIG.  10    is a cross-view illustrating an example taken along line I-I′ of the touch sensor shown in  FIG.  9   ; 
         FIG.  11    is an enlarged view illustrating an example of area EA of the first touch cell; 
         FIG.  12    is an enlarged view illustrating an example of the area EA of the second touch cell; 
         FIG.  13    is a cross-sectional view illustrating an example of a fine conductive line of the first touch cell and a fine conductive line of the second touch cell; 
         FIG.  14    is a plan view illustrating an example of a touch area of the touch sensor included in the display device shown in  FIG.  1   ; 
         FIG.  15    is a plan view illustrating an example of the touch area of the touch sensor included in the display device shown in  FIG.  1   ; 
         FIG.  16    is a plan view illustrating an example of the touch area of the touch sensor included in the display device shown in  FIG.  1   ; and 
         FIG.  17    is a plan view illustrating an example of the touch area of the touch sensor included in the display device shown in  FIG.  1   . 
     
    
    
     DETAILED DESCRIPTION 
     Example embodiments will now be described more fully hereinafter with reference to the accompanying drawings; however, they may be embodied in different forms and should not necessarily be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the example embodiments to those skilled in the art. 
     In the drawing figures, dimensions may be exaggerated for clarity of illustration. It will be understood that when an element is referred to as being “between” two elements, it can be the only element between the two elements, or one or more intervening elements may also be present. Like reference numerals may refer to like elements throughout the specification and the drawings. 
     Throughout the drawings, the same reference numerals may be given to the same elements, and to the extent that a detailed description for one or more elements has been omitted, it may be assumed that those elements are at least similar to corresponding elements that have been described elsewhere within the present disclosure. 
       FIG.  1    is a diagram illustrating a display device in accordance with embodiments of the present disclosure.  FIG.  2    is a cross-sectional view illustrating an example of a portion of a display area of the display device shown in  FIG.  1   . 
     Referring to  FIGS.  1  and  2   , the display device  1000  may include a display panel DP, a touch sensor TS, a fingerprint sensor FS, and a driver DRV. The driver DRV may include a display driver DDR and a sensor driver SDR. 
     In an embodiment, the display device  1000  may further include a printed circuit board on which at least a portion of the driver DRV is mounted. 
     The whole or at least a portion of the display device  1000  may be flexible. As used herein, the term “flexible” may mean that the element so-described may be bent, folded, rolled, and/or stretched to a non-trivial extent without cracking or otherwise sustaining damage. The display device  1000  may be implemented as a self-luminous display device including a plurality of self-luminous elements. For example, the display device  1000  may be an organic light emitting display device including organic light emitting elements, a display device including inorganic light emitting elements, or a display device including light emitting elements configured with a combination of inorganic and organic materials. However, the display device  1000  may be implemented as a liquid crystal display device, a plasma display device, a quantum dot display device, or the like. Light emitting elements included in the display panel DP of the quantum dot display device may include a quantum dot and/or a quantum rod. 
     The display device  1000  may be a flat panel display device, a flexible display device, a curved display device, a foldable display device, or a bendable display device. Also, the display device  1000  may be applied to a transparent display device, a head-mounted display device, a wearable display device, and the like. 
     A display surface on which an image is displayed may be parallel to a surface defined by a first direction DR 1  and a second direction DR 2 . A normal direction of the display surface, i.e., a thickness direction of the display device  1000  may be expressed as a third direction DR 3 . 
     The display panel DP includes a display area AA and a non-display area NA. The display area AA is an area in which a plurality of pixels PX are provided and may be referred to as an active area. Each of the pixels PX may include at least one light emitting element. The display device  1000  drives the pixels PX, corresponding to image data input from an external source, to display an image in the display area AA. 
     The non-display area NA is an area disposed at the periphery of the display area AA and may be referred to as a non-active area. For example, the non-display area NA includes a pad area, and may further include a line area, various dummy areas, and the like. The printed circuit board may be attached to the pad area. 
     In an embodiment, the display area AA may include a touch sensing area TSA. The touch sensing area TSA may be implemented by the touch sensor TS. For example, the touch sensor TS may be disposed corresponding to the display area AA of the display panel DP, and the touch sensing area TSA may be formed throughout the entire surface of the display area AA as shown in  FIG.  1   . 
     For example, as shown in  FIG.  2   , the touch sensor TS may be disposed corresponding to the touch sensing area TSA on the display panel DP. The touch sensor TS may include touch electrodes configured with touch cells arranged corresponding to the touch sensing area TSA. In an embodiment, the touch sensor may be a capacitance type touch sensor. For example, some of the touch electrodes (e.g., driving electrodes) may receive a touch driving signal, and other some of the touch electrodes (e.g., sensing electrodes) may output, as a touch sensing signal TSS, a variation in capacitance between the touch electrodes. When a portion of the body of a user is disposed on electrostatically coupled touch electrodes, a capacitance between the touch electrodes may be changed. 
     In addition, the display area AA may include a fingerprint sensing area FSA. The fingerprint sensing area FSA may be implemented by the fingerprint sensor FS. For example, the fingerprint sensor FS may include a plurality of sensor pixels SPX. The fingerprint sensing area FSA may be an area overlapping with the sensor pixels SPX. 
     In an embodiment, the touch sensing area TSA may include a first touch sensing area TSA 1  and a second touch sensing area TSA 2 . At least a portion of the second touch sensing area TSA 2  may overlap with the fingerprint sensing area FSA. In an embodiment, an RC delay of a touch sensing signal TSS provided in the second touch sensing area TSA 2  may be greater than an RC delay of a touch sensing signal TSS in the first touch sensing area TSA 1 . For example, a touch sensitivity of the second touch sensing area TSA 2  may be lower than a touch sensitivity of the first touch sensing area TSA 1 . This arrangement may be able to reduce the occurrence of touch malfunctions and touch misrecognitions of the second touch sensing area TSA 2  at a low temperature environment (e.g., 0° C. or lower), in touch sensor driving to which a baseline tracking method is applied. The driving using the baseline tracking method will be described below with reference to  FIGS.  5  and  6   . 
     The fingerprint sensing area FSA may overlap with at least a portion of the touch sensing area TSA. In an embodiment, as shown in  FIG.  1   , a portion of the display area AA may be set as the fingerprint sensing area FSA. For example, the fingerprint sensing area FSA may have a size similar to a fingerprint area of a thumb of an average-sized adult male. 
     However, the touch sensing area TSA and the fingerprint sensing area FSA may be formed in at least a portion of the non-display area NA of the display panel DP. 
     In an embodiment, the sensor pixels SPX may be configured with a photo sensor for sensing light. When light emitted from a light source (or pixel PX) provided in the display device  1000  is reflected by skin of a finger or the like of a user, the sensor pixels SPX may sense the reflected light and output a corresponding electrical signal (e.g., a voltage signal). An electrical signal of each of the sensor pixels SPX may constitute one dot in a fingerprint image (i.e., a dot of light and shade or a pixel as a minimum unit constituting the fingerprint image). Reflected light incident onto the respective sensor pixels SPX may have different optical characteristics (e.g., different frequencies, different wavelength, different intensities, or the like) according to whether the reflected light is caused by valleys or ridges of a fingerprint (or skin pattern) formed at the finger (or palm or skin) of the user. Therefore, the sensor pixels SPX may output sensing signals SS having different electrical characteristics, corresponding to the optical characteristics of the reflected light. 
     When the sensor pixels SPX are disposed in the fingerprint sensing area FSA, the sensor pixels SPX may overlap with the pixels PX or be disposed at the periphery of the pixels PX. For example, some or all of the sensor pixels SPX may overlap with the pixels PX or be disposed between the pixels PX. In various embodiments, the sensor pixels SPX and the pixels PX may have sizes equal to or different from each other. The relative size and arrangement of the sensor pixels SPX and the pixels are not necessarily limited to the arrangements described herein. 
     In an embodiment, the sensor pixels SPX may constitute an ultrasonic senor for sensing ultrasonic waves. The sensor pixels SPX may release an ultrasonic signal and sensing ultrasonic waves reflected by the finger of the user, thereby outputting corresponding electrical signals (or sensing signals SS). 
     In an embodiment, the sensor pixels SPX may constitute a capacitance sensor of which capacitance is changed according to shapes of fingerprints. 
     In an embodiment, as shown in  FIG.  2   , the fingerprint sensor FS including the sensor pixels SPX may be disposed on the other surface (e.g., a rear surface) opposite to one (e.g., a front surface) of both surfaces of the display panel DP, on which an image is displayed. However, the present disclosure is not necessarily limited thereto. For example, the sensor pixels SPX (i.e., the fingerprint sensor FS) may be disposed between the touch sensor TS and the display panel DP or be embedded in a backplane structure of the display panel DP. Also, the sensor pixels SPX may be disposed between the touch electrodes of the touch sensor TS. 
     In an embodiment, the display driver DDR and the sensor driver SDR may be disposed on the printed circuit board. However, a component having a function of at least a portion of the display driver DDR and the sensor driver SDR may be disposed directly on the display panel DP. 
     The display driver DDR may drive the display panel DP. For example, the display driver DDR may output a data signal DS corresponding to image data to the display panel DP. 
     The sensor driver SDR may drive the touch sensor TS and the fingerprint sensor FS. 
     In an embodiment, the sensor driver SDR may provide the touch sensor TS with a touch driving signal for driving the touch sensor TS. The sensor driver SDR may calculate a coordinate of a touch position by detecting a changed capacitance of a touch sensing signal TSS received from the touch sensor TS. 
     In an embodiment, the sensor driver SDR may output a driving signal (e.g., a control signal) for the sensor pixel SPX of the fingerprint sensor FS and receive sensing signals SS received from the sensor pixels SPX. 
       FIGS.  3 A to  3 D  are plan views illustrating examples of the touch sensor included in the display device shown in  FIG.  1   . 
     Referring to  FIGS.  1 ,  3 A,  3 B,  3 C, and  3 D , the touch sensor TS may include sensing electrodes RX 1  to RX 5 , first signal lines SL 1 - 1  to SL 1 - 5  connected to the sensing electrodes RX 1  to RX 5 , driving electrodes TX 1  to TX 4 , and second signal lines SL 2 - 1  to SL 2 - 4  connected to the driving electrodes TX 1  to TX 4 . 
     However, the sensing electrodes RX 1  to RX 5  and the driving electrodes TX 1  to TX 4  are not necessarily limited to a corresponding function. For example, the driving signals may be provided to the sensing electrodes RX 1  to RX 5  according to a form connected to the sensor driver SDR, and a touch position may be sensed based on signals provided from the driving electrodes TX 1  to TX 4 . 
     An external input may be sensed in a mutual capacitance manner using a capacitance change between the sensing electrodes RX 1  to RX 5  and the driving electrodes TX 1  to TX 4 . 
     In an embodiment, the touch sensor TS may further include an optical dummy electrode disposed in a boundary area between the sensing electrodes RX 1  to RX 5  and the driving electrodes TX 1  to TX 4 . 
     The sensing electrodes RX 1  to RX 5  and the driving electrodes TX 1  to TX 4  intersect each other. The sensing electrodes RX 1  to RX 5  are arranged in substantially parallel to the first direction DR 1 , and each of the sensing electrodes RX 1  to RX 5  has a shape extending in parallel to the second direction DR 2 . 
     In an embodiment, the sensing electrodes RX 1  to RX 5  and the driving electrodes TX 1  to TX 4  may have a shape (e.g., a bar shape) in which touch cells TSE and a connection part connecting the same are not distinguished from each other. Although a rhombic touch cells TSE are exemplarily illustrated, the present disclosure is not necessarily limited thereto, and the touch cells TSE may each have another polygonal shape. 
     In an embodiment, the sensing electrodes RX 1  to RX 5  and the driving electrodes TX 1  to TX 4  may be formed in a mesh pattern. 
     In an embodiment, a touch sensing area TSA may include a first touch sensing area TSA 1  and a second touch sensing area TSA 2 . For example, first to third sensing electrodes RX 1  to RX 3  may be included in the first touch sensing area TSA 1 , and fourth and fifth sensing electrodes RX 4  and RX 5  may be included in the second touch sensing area TSA 2 . Each of first to fourth driving electrodes TX 1  to TX 4  may be formed throughout the first touch sensing area TSA 1  and the second sensing area TSA 2 . 
     Each of the sensing electrodes RX 1  to RX 5  and the driving electrodes TX 1  to TX 4  may include touch cells TSE. The touch cells TSE may include a first touch cell TSE 1  formed in the first touch sensing area TSA 1  and a second touch cell TSE 2  formed in the second touch sensing area TSA 2 . 
     For example, the first touch cell TSE 1  may include a first sensing touch cell RX_SE 1  and a first driving touch cell TX_SE 1 . The second touch cell TSE 2  may include a second sensing touch cell RX_SE 2  and a second driving touch cell TX_SE 2 . 
     The first sensing touch cell RX_SE 1  may constitute the first to third sensing electrodes RX 1  to RX 3  of the first touch sensing area TSA 1 , and the second sensing touch cell RX_SE 2  may constitute the fourth and fifth sensing electrodes RX 4  and RX 5  of the second touch sensing area TSA 2 . The first driving touch cell TX_SE 1  may constitute a portion at which the first to fourth driving electrodes TX 1  to TX 4  overlap with the first touch sensing area TSA 1 , and the second driving touch cell TX_SE 2  may constitute a portion at which the first to fourth driving electrodes TX 1  to TX 4  overlap with the second touch sensing area TSA 2 . 
     The first driving touch cell TX_SE 1  and the second driving touch cell TX_SE 2  are components electrically and physically connected to each other. In an embodiment, it may be understood that the first driving touch cell TX_SE 1  and the second driving touch cell TX_SE 2  are components substantially identical to each other. 
     Configurations and/or shapes of the first sensing touch cell RX_SE 1  and the second sensing touch cell RX_SE 2  may be equal to each other and be designed differently from each other. 
     The first sensing touch cell RX_SE 1  or the second sensing touch cell RX_SE 2  may be arranged along the second direction DR 2  in one sensing electrode. For example, the first sensing touch cell RX_SE 1  may be arranged along the second direction DR 2  in the first sensing electrode RX 1  of the first touch sensing area TSA 1 , and the second sensing touch cell RX_SE 2  may be arrange along the second direction DR 2  in the fourth sensing electrode RX 4  of the second touch sensing area TSA 2 . 
     The first driving touch cell TX_SE 1  may be arranged along the first direction DR 1  in one driving electrode (e.g., the first touch sensing area TSA 1  of the first driving electrode TX 1 ), and the second driving touch cell TX_SE 2  may be arranged along the first direction DR 1  in the driving electrode (e.g., the second touch sensing area TSA 2  of the first driving electrode TX 1 ). 
     As shown in  FIG.  3 A , the first signal lines SL 1 - 1  to SL 1 - 5  are respectively connected to a single end of the sensing electrodes RX 1  to RX 5 . In addition, the second signal lines SL 2 - 1  to SL 2 - 4  are connected to opposite ends of the driving electrodes TX 1  to TX 4 . 
     In an embodiment, as shown in  FIG.  3 B , the first signal lines SL 1 - 1  to SL 1 - 5  may be connected to opposite ends of the sensing electrodes RX 1  to RX 5 . 
     In an embodiment, as shown in  FIG.  3 C , the second signal lines SL 2 - 1  to SL 2 - 4  may be respectively connected to only a single end of the driving electrodes TX 1  to TX 4 . 
     In an embodiment, as shown in  FIG.  3 D , the first signal lines SL 1 - 1  to SL 1 - 5  may be alternately connected respectively to opposite ends of the sensing electrodes RX 1  to RX 5 . For example, odd-numbered first signal lines SL 1 - 1 , SL 1 - 3 , and SL 1 - 5  may be respectively connected to first ends of odd-numbered sensing electrodes RX 1 , RX 3 , and RX 5 , and even-numbered first signal lines SL 1 - 2  and SL 1 - 4  may be respectively connected to second ends (e.g., end portions of the opposite surfaces of the one ends) of even-numbered sensing electrodes RX 2  and RX 4 . 
     However, the connections between the signal lines SL 1 - 1  to SL 1 - 5  and SL 2 - 1  to SL 2 - 4  and the electrodes TX 1  to TX 4  and RX 1  to RX 5  are not necessarily limited thereto. 
     In an embodiment, a line resistance of the first signal lines SL 1 - 4  and SL 1 - 5  corresponding to the second touch sensing area TSA 2  may be greater than a line resistance of the first signal lines SL 1 - 1 , SL 1 - 2 , and SL 1 - 3  corresponding to the first touch sensing area TSA 1 . For example, a line width of the first signal lines SL 1 - 4  and SL 1 - 5  may be narrower than a line width of the first signal lines SL 1 - 1 , SL 1 - 2 , and SL 1 - 3 . A line thickness (e.g., thickness in the third direction DR 3 ) of the first signal lines SL 1 - 4  and SL 1 - 5  may be smaller than a line thickness of the first signal lines SL 1 - 1 , SL 1 - 2 , and SL 1 - 3 . Therefore, an RC delay of a touch sensing signal TSS corresponding to the second touch sensing area TSA 2  may be greater than an RC delay of a touch sensing signal TSS corresponding to the first touch sensing area TSA 1 . 
     The first signal lines SL 1 - 1  to SL 1 - 5  and the second signal lines SL 2 - 1  to SL 2 - 4  may include pad parts SL-P. The pad parts SL-P may be aligned in a pad area NDA-PD. 
     However, the planar shape of the touch sensor TS is not necessarily limited thereto. 
       FIG.  4    is a plan view illustrating an example of the sensing cells included in the touch sensor shown in  FIG.  3 A . 
     Referring to  FIGS.  3 A and  4   , touch cells TSE may include driving touch cells TX_SE and sensing touch cells RX_SE. 
     The driving touch cells TX_SE and the sensing touch cells RX_SE, which are shown in  FIG.  4   , may be included in the first touch sensing area TSA 1  and/or the second touch sensing area TSA 2 . 
     The driving touch cells TX_SE may be arranged in the first direction DR 1  and may be electrically connected to each other by a first connection pattern CNP 1 . The sensing touch cells RX_SE may be arranged in the second direction DR 2  and may be electrically connected through the second connection pattern CNP 2 . The driving touch cells TX_SE and the first connection pattern CNP 1  may form the driving electrode TX 1  to TX 4 , and the sensing touch cells RX_SE and the second connection pattern CNP 2  may form the sensing electrodes RX 1  to RX 5 . 
     In an embodiment, the second connection pattern CNP 2 , the driving touch cells TX_SE, and the sensing touch cells RX_SE may be disposed in the same layer, and the first connection pattern CNP 1  may be disposed in a layer different from the layer of the second connection pattern CNP 2 , the driving touch cells TX_SE, and the sensing touch cells RX_SE. Accordingly, the driving electrodes TX 1  to TX 4  and the sensing electrodes RX 1  to RX 5  are not short-circuited with each other. 
     In an embodiment, each of the driving touch cells TX_SE and the sensing touch cells RX_SE may include a touch pattern area TPA including a touch pattern and a dummy pattern area DPA including a dummy pattern. The touch pattern and the dummy pattern are insulated from each other. For example, the dummy pattern may be disposed in a floating state. Therefore, the dummy pattern might not include a path along which current may flow. In addition, a plurality of dummy pattern areas DPA respectively including dummy patterns may be included in each of the driving touch cells TX_SE and the sensing touch cell RX_SE. The dummy pattern areas DPA may be regularly arranged or be randomly arranged. 
     The dummy pattern of the dummy pattern area DPA decreases a difference in external light reflexibility, so that the probability that a pattern blur of the touch cell TSE will be visible to a user can be reduced. 
     In an embodiment, the touch pattern areas TPA configured with the touch pattern as a conductor may be integrally formed. The touch pattern and the dummy pattern are spaced apart from each other. 
     In an embodiment, the touch pattern area TPA and the dummy pattern area DPA may include a mesh pattern configured with fine conductive lines so as to increase image visibility and image quality. 
       FIG.  5    is a diagram illustrating an example of updating a baseline according to a change in raw data corresponding to a touch sensing signal. 
     Referring to  FIGS.  1 ,  3 A, and  5   , the sensor driver SDR may set (e.g., update) a baseline BL, based on a touch sensing signal TSS. 
     In an embodiment, the touch sensing signal TSS may be defined or generated based on a difference between raw data provided from the first signal lines SL 1 - 1  to SL 1 - 5  and the baseline BL. The raw data may be changed according to a touch input, in proportion to a mutual capacitance between a sensing electrode and a driving electrode, which are formed in the touch sensing area TSA. Also, the raw data (i.e., the mutual capacitance) may be changed in response to a peripheral temperature change. 
     The baseline BL may be understood as a reference value of a capacitance formed in each of the sensing electrodes RX 1  to RX 5  and the driving electrodes TX 1  to TX 4  or a base capacitance (or reference capacitance). For example, a base capacitance of each of the sensing electrodes RX 1  to RX 5  may be a capacitance between each of the sensing electrodes RX 1  to RX 5  and a system ground in a state in which there is no user input. In addition, a base capacitance of each of the driving electrodes TX 1  to TX 4  may be a capacitance between each of the driving electrodes TX 1  to TX 4  and the system ground in a state in which there is no user input. The system ground may be set as a conductor, to which a DC power source is provided, or a real ground. 
     In an embodiment, the system ground may be integrally formed in the display area of the display panel DS on the bottom of the touch sensor TS and may be set as a common electrode constituting the light emitting element (e.g., a cathode electrode of the light emitting element). A voltage of the DC power source for light emission of the light emitting element may be provided to the common electrode of the display panel DP. 
     The sensor driver SDR may recognize a touch of the user, based on a variation in raw data with respect to the baseline BL. For example, a reference for determining a variation dCM in mutual capacitance may be the baseline BL. When the variation dCM in mutual capacitance is greater than a predetermined reference value, the sensor driver SDR may determine that a touch input has occurred. 
     The raw data is influenced by not only the touch input but also a peripheral environment factor (particularly, a peripheral temperature change). Similarly, a value of the baseline BL understood as the base capacitance may also be influenced by the peripheral temperature change. Therefore, when a fixed value of the baseline BL is compared with the raw data, an accurate variation in mutual capacitance, which is caused by the touch, may be calculated. 
     For example, the mutual capacitance may be proportional to a dielectric constant of an insulator between the sensing electrode and the driving electrode, and the dielectric constant may be changed with temperature. Accordingly, the mutual capacitance and the base capacitance corresponding to the baseline BL may become greater as the temperature becomes higher. 
     Therefore, the sensor driver SDR may reset the baseline BL by cyclically or non-cyclically determining a change in the raw data or a value of the raw data. 
     For example, the sensor driver SDR may update an existing first baseline BL 1  to a second baseline BL 2  by using raw data calculated at a first time TP 1 . The baseline BL used during a predetermined period after the first time TP 1  may be a value of the second baseline BL 2 . 
     When the raw data is changed as a touch is input at a second time TP 2 , a variation in raw data with respect to the second baseline BL 2  may be output as the variation dCM in mutual capacitance. Accordingly, the sensor driver SDR can sense a touch input at a corresponding position. 
     When the first baseline BL 1  is maintained at the second time TP 2 , the variation dCM in mutual capacitance may be calculated as a much smaller value, and touch recognition might not be made. 
     As described above, the sensor driver SDR may determine a touch input by using a baseline tracking method of updating the value of the baseline BL by reflecting a touch peripheral temperature change. Thus, the accuracy of touch recognition may be increased. 
       FIG.  6    is a diagram illustrating an example of a change in raw data according to a touch input in a low temperature condition and a baseline updated according the change in raw data. 
     Referring to  FIGS.  1 ,  3 A,  5 , and  6   , the value of the baseline BL may be changed by a sudden change in temperature according to occurrence of a touch input in a low temperature condition. 
     For example, the low temperature condition may be an environment of 0° C. or lower. However, the low temperature condition is not necessarily limited thereto. 
     A first period P 1  and a third period P 3  are in a state in which no touch input exists, and a touch input is made during a second period P 2 . For example, the second period P 2  may be a period in which a contact of a finger with respect to the touch sensing area TSA is maintained during a relatively long time. 
     At a third time TP 3 , a value of raw data corresponding to the mutual capacitance may be decreased by the touch input. In addition, during the second period P 2  in which a touch state is maintained, a temperature of a touched portion may increase due to a body temperature, and the value of the raw data may increase. 
     When the touch is released at a fourth time TP 4 , the raw data may again increase by a magnitude of the mutual capacitance which was dropped at the third time TP 3 . Accordingly, the baseline BL may be updated from a value of a third baseline BL 3  to a value of a fourth baseline BL 4  by driving using the baseline tracking method. 
     In addition, during the third period P 3 , a temperature of the touch sensor TS may be rapidly lowered by a peripheral temperature, and therefore, the raw data (i.e., the mutual capacitance) may be rapidly changed (e.g., represented by a first curve L 1  in  FIG.  6   ). When the raw data is rapidly decreased before the baseline is again updated, the sensor driver SDR may misrecognize a touch. For example, in the third period P 3  in which no touch input exists, a touch may be recognized at a corresponding position (referred to as a ghost touch). 
     To reduce touch misrecognition in a low temperature environment by using the baseline tracking method, a variation in mutual capacitance per time may be decreased, which is used to prevent a sudden change in raw data in the third period. For example, when a change in raw data such as the first curve L 1  in the third period P 3  becomes gradual such as a second curve L 2  until the baseline BL is again updated, touch misrecognition can be reduced. 
     In an embodiment, an RC delay of a corresponding touch sensing area may be increased so as to decrease the variation in mutual capacitance per time. However, an RC delay of the entire touch sensing area is increased, touch sensitivity and accuracy may be decreased, and accordingly, a method of increasing an RC delay only in a required partial area. 
     In particular, the area in which the fingerprint sensor FS is disposed may be used for releasing a lock state of an electronic device including the display device  1000 , and the structure of the touch sensor TS may be modified such that touch recognition of the corresponding part in an extreme environment of a low temperature or high temperature is easily made (e.g., touch recognition may be resilient against a temperature change). 
     For example, a structure in which a resistance component and/or a capacitance component of the corresponding part is increased may be applied so as to increase an RC delay of a touch sensing signal TSS in the area in which the fingerprint sensor FS is disposed. 
       FIG.  7    is a plan view illustrating an example of the first touch cell and the second touch cell, which are included in the touch sensor shown in  FIG.  3 A .  FIG.  8    is a plan view illustrating an example of the first touch cell and the second touch cell, which are included in the touch sensor shown in  FIG.  3 A . 
     Referring to  FIGS.  1 ,  3 A,  4 ,  7 , and  8   , the first touch cell TSE 1  may include a first area (or, a first touch pattern area) TPA 1  in which a first touch pattern is disposed and a first dummy pattern area DPA 1  in which a first dummy pattern is disposed, and the second touch cell TSE 2  may include a second area (or, a second touch pattern area) TPA 2  in which a second touch pattern is disposed and a second dummy pattern area DPA 2  in which a second dummy pattern is disposed. 
     A total area of the first dummy pattern area DPA 1  of each first touch cell TSE 1  may be greater than a total area of the second dummy pattern area DPA 2  of each second touch cell TSE 2 . In an embodiment, as shown in  FIG.  7   , an area of each first dummy pattern area DPA 1  may be greater than an area of each second dummy pattern area DPA 2 . In an embodiment, as shown in  FIG.  8   , a number of first dummy pattern areas DPA 1  may be greater than a number of second dummy pattern areas DPA 2 . 
     Accordingly, an area of the first area TPA 1  of the first touch cell TSE 1  may be smaller than an area of the second area TPA 2  of the second touch cell TSE 2 . For example, a magnitude of a base capacitance of the second touch cell TSE 2  may be greater than a magnitude of a base capacitance of the first touch cell TSE 1  actually involved in touch recognition. 
     Therefore, an RC delay of a touch sensing signal TSS provided in the second touch sensing area TSA 2  may be greater than an RC delay of a touch sensing signal TSS provided in the first touch sensing area TSA 1 . Accordingly, touch misrecognition of the second touch sensing area TSA 2  in an extreme environment of a low temperature condition or the like can be reduced. 
     In an embodiment, the touch patterns and the dummy patterns may include a mesh pattern formed with fine conductive lines. 
     In an embodiment, the first touch cell TSE 1  may include a first sensing touch cell RX_SE 1  and a first driving touch cell TX_SE 1 . The second touch cell TSE 2  may include a second sensing touch cell RX_SE 2  and a second driving touch cell RX_SE 2 . 
     However, the first and second dummy pattern areas DPA 1  and DPA 2  shown in  FIG.  7    and/or  FIG.  8    may be applied exclusively to the first sensing touch cell RX_SE 1  and the second sensing touch cell RX_SE 2 . For example, the first driving touch cell TX_SE 1  and the second driving touch cell TX_SE 2 , which are electrically connected to each other, may have the same shape. 
       FIG.  9    is a schematic diagram illustrating an example of the touch sensor shown in  FIG.  3 A .  FIG.  10    is a cross-sectional view illustrating an example taken along line I-I′ of the touch sensor shown in  FIG.  9   . 
     Referring to  FIGS.  1 ,  3 A, and  9   , the touch sensor TS may include touch electrodes configured with touch cells arranged corresponding to a touch sensing area TSA and sensing lines SSL 1  and SSL 2  connected to the touch electrodes. 
     In  FIG.  9   , for convenience of description, illustration of the sensing electrodes RX 1  to RX 5 , the driving electrodes TX 1  to TX 4 , and the second signal lines SL 2 - 1  to SL 2 - 4 , which are shown in  FIG.  3 A , will be omitted. However, it is to be understood that these omitted elements may indeed be present within the displayed apparatus. 
     The touch sensing area TSA may include a first touch sensing area TSA 1  and a second touch sensing area TSA 2 . 
     First sensing lines SSL 1  and second sensing lines SSL 2  may include the first signal lines SL 1 - 1  to SL 1 - 5  shown in  FIG.  3 A . The first sensing lines SSL 1  may be connected to sensing electrodes of the first touch sensing area TSA 1 , and the second sensing lines SSL 2  may be connected to sensing electrodes of the second touch sensing area TSA 2 . As described above, an RC delay of a touch sensing signal TSS corresponding to the second touch sensing area TSA 2  may be greater than an RC delay of a touch sensing signal TSS corresponding to the first touch sensing area TSA 1 . To this end, a line resistance of the second sensing lines SSL 2  may be designed to be greater than a line resistance of the first sensing lines SSL 1 . 
     Each of the first and second sensing lines SSL 1  and SSL 2  may include a part extending in the second direction DR 2  and a part extending in the first direction DR 1 . Each of the first and second sensing lines SSL 1  and SSL 2  may extend to the pad area NDA-PD. 
       FIG.  10    illustrates a section of a first portion PO 1  of one (hereinafter, referred to as a first sensing line SSL 1   a ) of the first sensing lines SSL 1  and a second portion PO 2  of one (hereinafter, referred to as a second sensing line SSL 2   a ) of the second sensing lines SSL 2 . In an embodiment, the first sensing line SSL 1   a  and the second sensing line SSL 2   a  may be disposed on a first insulating layer IL 1 . 
     The first insulating layer IL 1  may be disposed on an encapsulation layer of the display panel DP. The first insulating layer IL 1  may include an organic insulating material and/or an inorganic insulating material. For example, the first insulating layer IL 1  may include silicon oxide, silicon nitride, and/or silicon oxynitride. 
     The first sensing line SSL 1   a  and the second sensing line SSL 2   a  may include a conductive material. The conductive material may include a transparent conductive oxide or a metal material. For example, the first sensing line SSL 1   a  and the second sensing line SSL 2   a  may include molybdenum, silver, titanium, copper, aluminum, and/or alloys thereof. Alternatively, the first sensing line SSL 1   a  and the second sensing line SSL 2   a  may include a transparent conductive oxide such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), and/or indium tin zinc oxide (ITZO). The transparent conductive material may include conductive polymer such as PEDOT, metal nanowire, graphene, and the like. 
     In an embodiment, as shown in  FIGS.  9  and  10   , a width of the first sensing line SSL 1   a  in a horizontal direction may be greater than a width of the second sensing line SSL 2   a  in the horizontal direction. For example, the width of the second sensing line SSL 2   a  may be equal to or smaller than 70% of the width of the first sensing line SSL 1   a.    
     In an embodiment, a thickness (e.g., a thickness in the third direction DR 3  shown in  FIG.  2   ) of the first sensing line SSL 1   a  may be greater than a thickness of the second sensing line SSL 2   a . For example, the thickness of the second sensing line SSL 2   a  may be equal to or smaller than 70% of the thickness of the first sensing line SSL 1   a.    
     Therefore, a resistance of the second sensing line SSL 2   a  may be greater than a resistance of the first sensing line SSL 1   a.    
     In an embodiment, the first sensing line SSL 1   a  and the second sensing line SSL 2   a  may have different thicknesses through a sputtering process of directly depositing a conductive pattern. Alternatively, in an embodiment, the first sensing line SSL 1   a  and the second sensing line SSL 2   a  may have different thicknesses and/or different widths through process such as dry etching or wet etching with respect to an entirely deposited conductive material. 
     A second insulating layer IL 2  covering the first sensing line SSL 1   a  and the second sensing line SSL 2   a  may be disposed on the first insulating layer IL 1 . The second insulating layer IL 2  may include silicon oxide, silicon nitride, and/or silicon oxynitride. 
     Although a case where the width and thickness of the first sensing line SSL 1   a  are respectively greater than the width and thickness of the second sensing line SSL 2   a  is illustrated in  FIG.  10   , the present disclosure is not necessarily limited thereto. For example, the width of the first sensing line SSL 1   a  and the width of the second sensing line SSL 2   a  may be substantially equal to each other, and the thickness of the first sensing line SSL 1   a  may be greater than the thickness of the second sensing line SSL 2   a . Alternatively, the thickness of the first sensing line SSL 1   a  and the thickness of the second sensing line SSL 2   a  may be substantially equal to each other, and the width of the first sensing line SSL 1   a  may be greater than the width of the second sensing line SSL 2   a.    
     As described above, a resistance of the second sensing lines SSL 2  is greater than a resistance of the first sensing lines SSL 1 , so that an RC delay of a touch sensing signal TSS provided in the second touch sensing area TSA 2  can be greater than an RC delay of a touch sensing signal TSS provided in the first touch sensing area TSA 1 . Thus, touch recognition of the second touch sensing area TSA 2  can be strong and resilient to a temperature change. 
     In an embodiment, the configuration of the first and second sensing lines SSL 1  and SSL 2  shown in  FIG.  9    and the configuration of the dummy pattern areas DPA 1  and DPA 2  described with reference to  FIG.  8    may be designed to be combined with each other. 
       FIG.  11    is an enlarged view illustrating an example of area EA of the first touch cell.  FIG.  12    is an enlarged view illustrating an example of the area EA of the second touch cell.  FIG.  13    is a cross-sectional view illustrating an example of a fine conductive line of the first touch cell and a fine conductive line of the second touch cell. 
     Referring to  FIGS.  3 A,  4 ,  11 ,  12 , and  13   , the first touch cell TSE 1  may include a first touch pattern TCP 1  and a first dummy pattern DMP 1 , and the second touch cell TSE 2  may include a second touch pattern TCP 2  and a second dummy pattern DMP 2 . 
     The first touch pattern TCP 1  and the first dummy pattern DMP 1  may be spaced apart from each other and may be electrically insulated from each other. Similarly, the second touch pattern TCP 2  and the second dummy pattern DMP 2  may be spaced apart from each other and may be electrically insulated from each other. 
     In an embodiment, the first touch cell TSE 1  may include a first sensing touch cell RX_SE 1  and a first driving touch cell TX_SE 1 . The second touch cell TSE 2  may include a second sensing touch cell RX_SE 2  and a second driving touch cell RX_SE 2 . 
     The first touch pattern TCP 1  and the first dummy pattern DMP 1 , which are shown in  FIG.  11   , may be applied to only the first sensing touch cell RX_SE 1 , and the second touch pattern TCP 2  and the second dummy pattern DMP 2 , which are shown in  FIG.  12   , may be applied to only the second sensing touch cell RX_SE 2 . For example, the first driving touch cell TX_SE 1  and the second driving touch cell RX_SE 2 , which are electrically connected to each other, may have the same shape. 
     In an embodiment, the first touch pattern TCP 1  and the second touch pattern TCP 2  may include a mesh pattern. The first touch pattern TCP 1  may include a first fine conductive line CFL 1  and a second fine conductive line CFL 2 , which intersect each other. The second touch pattern TCP 2  may include a third fine conductive line CFL 3  and a fourth fine conductive line CFL 4 , which intersect each other. 
     In an embodiment, as shown in  FIGS.  11  and  12   , a width of the first and second fine conductive lines CFL 1  and CFL 2  may be greater than a width of the third and fourth fine conductive lines CFL 3  and CFL 4 . Therefore, a resistance of the second touch pattern TCP 2  may be greater than a resistance of the first touch pattern TCP 1 , and an RC delay of a touch sensing signal TSS corresponding to the second touch sensing area TSA 2  may be greater than an RC delay of a touch sensing signal TSS corresponding to the first touch sensing area TSA. 
     For example, the width of the third and fourth fine conductive lines CFL 3  and CFL 4  may be equal to or smaller than 70% of the width of the first and second fine conductive lines CFL 1  and CFL 2 . The second fine conductive line CFL 2  and the fourth fine conductive line CFL 4  may be disposed in the same layer as the first fine conductive line CFL 1  and the third fine conductive line CFL 3 . The conductive material constituting the first to fourth fine conductive lines CFL 1 , CFL 2 , CFL 3 , and CFL 4  may include a transparent conductive material, a transparent conductive oxide, or a metal material. 
     In an embodiment, the first fine conductive line CFL 1  and the second fine conductive line CFL 2  may be thicker than the third fine conductive line CFL 3  and the fourth fine conductive line CFL 4 . Therefore, a resistance of the second touch pattern TCP 2  may be greater than a resistance of the first touch pattern TCP 1 , and an RC delay of a touch sensing signal TSS corresponding to the second touch sensing area TSA 2  may be greater than an RC delay of a touch sensing signal TSS corresponding to the first touch sensing area TSA. 
     For example, a thickness of the third and fourth fine conductive lines CFL 3  and CFL 4  may be equal to or smaller than a thickness of the first and second fine conductive lines CFL 1  and CFL 2 . 
     In an embodiment, the first touch pattern TCP 1  and the second touch pattern TCP 2  may have different thicknesses through a sputtering process of directly depositing a conductive pattern. In an embodiment, the first touch pattern TCP 1  and the second touch pattern TCP 2  may have different thicknesses and/or different widths through a process such as dry etching or wet etching with respect to an entirely deposited conductive material. 
     In an embodiment, the first dummy pattern DMP 1  and the second dummy pattern DMP 2  may include a mesh pattern. The first dummy pattern DMP 1  may include a first dummy fine conductive line DCFL 1  and a second dummy fine conductive line DCFL 2 , which intersect each other. The second dummy pattern DMP 2  may include a third dummy fine conductive line DCFL 3  and a fourth dummy fine conductive line DCFL 4 , which intersect each other. 
     In an embodiment, as shown in  FIGS.  11  and  12   , a width of the first and second dummy fine conductive lines DCFL 1  and DCFL 2  may be greater than a width of the third and fourth dummy fine conductive lines DCFL 3  and DCFL 4 . In addition, a thickness of the first and second dummy fine conductive lines DCFL 1  and DCFL 2  may be greater than a thickness of the third and fourth dummy fine conductive lines DCFL 3  and DCFL 4 . For example, in terms of process convenience, the first and second dummy fine conductive lines DCFL 1  and DCFL 2  may have the substantially same width and thickness as the first and second fine conductive lines CFL 1  and CFL 2 , and the third and fourth dummy fine conductive lines DCFL 3  and DCFL 4  may have the substantially same width and thickness as the third and fourth fine conductive lines CFL 3  and CFL 4 . 
     As described above, the resistance of the second touch pattern TCP 2  is formed greater than the resistance of the first touch pattern TCP 1 , so that an RC delay of a touch sensing signal TSS provided in the second touch sensing area TSA 2  can be greater than an RC delay of a touch sensing signal TSS provided in the first touch sensing area TSA 1 . Touch recognition of the second touch sensing area TSA 2  can be resilient to a temperature change. 
     In an embodiment, the configuration of the first and second touch cells TSE 1  and TSE 2  shown in  FIGS.  11  to  13    may be designed to be combined with the configuration of the first and second sensing lines SSL 1  and SSL 2  and/or the configuration of the dummy pattern areas DPA 1  and DPA 2  described with reference to  FIGS.  7  and  8   . 
       FIG.  14    is a plan view illustrating an example of a touch area of the touch sensor included in the display device shown in  FIG.  1   .  FIG.  15    is a plan view illustrating an example of the touch area of the touch sensor included in the display device shown in  FIG.  1   .  FIG.  16    is a plan view illustrating an example of the touch area of the touch sensor included in the display device shown in  FIG.  1   .  FIG.  17    is a plan view illustrating an example of the touch area of the touch sensor included in the display device shown in  FIG.  1   . 
     Referring to  FIGS.  1 ,  3 A,  14 ,  15 ,  16 , and  17   , the touch sensing area TSA of the touch sensor TS may include a first touch sensing area TSA 1  and a second touch sensing area TSA 2 . 
     An RC delay of a touch sensing signal TSS corresponding to the second touch sensing area TSA 2  may be greater than an RC delay of a touch sensing signal TSS corresponding to the first touch sensing area TSA 1 . In an embodiment, as described with reference to  FIGS.  7  and  8   , a total area of a dummy pattern area of an individual touch cell of the second touch sensing area TSA 2  may be smaller than a total area of a dummy pattern area of an individual touch cell of the first touch sensing area TSA 1 . In an embodiment, as described with reference to  FIGS.  11  and  12   , a resistance of the second touch pattern TCP 2  of the second touch sensing area TSA 2  may be greater than a resistance of the first touch pattern TCP 1  of the first touch sensing area TSA 1 . 
     In an embodiment, as shown in  FIG.  14   , a second touch sensing area TSA 2  may have a size corresponding to the shape of a fingerprint sensing area FSA. In a normal condition, the second touch sensing area TSA 2  having a relatively large RC delay has a touch sensitivity lower than a touch sensitivity of the first touch sensing area TSA 1 . Thus, the area of the second touch sensing area TSA 2  is minimized, thereby minimizing lowering of the entire touch sensitivity. 
     In an embodiment, as shown in  FIG.  15   , a first touch sensing area TSA 1  may include a plurality of first sub-touch sensing areas TSA 1   a , TSA 1   b , TSA 1   c , and TSA 1   d , and a second touch sensing area TSA 2  may include a plurality of second sub-touch sensing areas TSA 2   a , TSA 2   b , and TSA 2   c . The first sub-touch sensing areas TSA 1   a , TSA 1   b , TSA 1   c , and TSA 1   d  and the second sub-touch sensing areas TSA 2   a , TSA 2   b , and TSA 2   c  may be alternately disposed in the first direction DR 1 . An area of the second touch sensing area TSA 2  is decreased, so that the lowering of the entire touch sensitivity can be reduced. RC delays respectively corresponding to the second sub-touch sensing areas TSA 2   a , TSA 2   b , and TSA 2   c  may be equal to or different from one another. 
     In an embodiment, as shown in  FIG.  16   , a second touch sensing area TSA 2  may include a plurality of sub-touch sensing areas S_TSA 1 , S_TSA 2 , S_TSA 3 , S_TSA 4 , and S_TSA 5 . An RC delay corresponding to the sub-touch sensing areas S_TSA 1 , S_TSA 2 , S_TSA 3 , S_TSA 4 , and S_TSA 5  may be gradually changed in the first direction DR 1 . For example, an area of a dummy pattern area of an individual cell of each of the sub-touch sensing areas S_TSA 1 , S_TSA 2 , S_TSA 3 , S_TSA 4 , and S_TSA 5  may gradually decrease (i.e., an increase in base capacitance). Alternatively, a width and/or a thickness of a touch pattern of each of the sub-touch sensing areas S_TSA 1 , S_TSA 2 , S_TSA 3 , S_TSA 4 , and S_TSA 5  may gradually decrease (i.e., an increase in resistance). 
     Thus, touch sensitivity in the second touch sensing area TSA 2  may be maintained. 
     In an embodiment, as shown in  FIG.  17   , the display panel DP may display a keypad image IMG. A second touch sensing area TSA 2  may overlap with an area in which the keypad image IMG is displayed. Thus, the accuracy of a key input using a touch in an extreme situation of a low temperature condition or the like can be increased. 
     As described above, the touch sensor and the display device including the same in accordance with the embodiments of the present disclosure may include a second touch sensing area TSA 2  overlapping with a fingerprint sensor FSA and/or a keypad image IMG. A capacitance of the touch cells, a resistance of the touch cells, and/or a resistance of the sensing lines may be designed differently for each touch sensing area such that an RC delay of a touch sensing signal corresponding to the second touch sensing area TSA 2  is greater than an RC delay of a touch sensing signal corresponding to another touch sensing area. Thus, in the touch sensor and the display device including the same, which are driven by using the baseline tracking method, lowering of touch sensitivity can be minimized, and simultaneously, touch misrecognition/malfunction of the second touch sensing area TSA 2  in an extreme environment of a low temperature or high temperature condition can be reduced (e.g., resilience against a temperature change). 
     Further, the design of a touch sensor structure is partially changed in a hardware manner, so that malfunction in a low temperature environment can be prevented. Accordingly, cost for software touch compensation driving to prepare for a low temperature environment and manufacturing cost can be reduced. 
     In some instances, as would be apparent to one of ordinary skill in the art as of the filing of the present application, features, characteristics, and/or elements described in connection with a particular embodiment may be used singly or in combination with features, characteristics, and/or elements described in connection with other embodiments unless otherwise specifically indicated. Accordingly, it will be understood by those of skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present disclosure.