Patent Publication Number: US-2023147678-A1

Title: Flexible electronic device

Description:
BACKGROUND OF THE DISCLOSURE 
     1. Field of the Disclosure 
     The present disclosure relates to a flexible electronic device, and more particularly to a flexible electronic device including a protruding unit. 
     2. Description of the Prior Art 
     In recent years, flexible electronic devices are widely applied in various electronic products, such as smart phones, tablets, notebook computers, televisions, vehicle displays or wearable devices. With the wide application of electronic products, manufacturers keep on researching and developing for new flexible electronic devices, and have higher expectations for the user experience and reliability of products. 
     SUMMARY OF THE DISCLOSURE 
     Some embodiments of the present disclosure provide a flexible electronic device, through the design of the appropriate proportion for the area of the deformation region of the flexible substrate and the area of the sensing unit disposed on the flexible substrate, the sensing units may not be easily damaged by the deformation of the flexible substrate when the flexible substrate is deformed by the protruding unit and also provide a good sensing effect. 
     Some embodiments of the present disclosure provide a flexible electronic device including a protruding unit, a flexible substrate and a plurality of sensing units. The flexible substrate is disposed on the protruding unit and has a deformation region corresponding to the protruding unit. The sensing units are disposed on the flexible substrate, and at least one of the sensing units is overlapped with the deformation region. A ratio of an area of the deformation region to an area of one of the at least one of the sensing units is greater than or equal to 1.4 and less than or equal to 2222. 
     These and other objectives of the present disclosure will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the embodiment that is illustrated in the various figures and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a cross-sectional view schematic diagram of a flexible electronic device according to a first embodiment of the present disclosure. 
         FIG.  2    is a three-dimensional schematic diagram of the flexible electronic device according to the first embodiment of the present disclosure. 
         FIG.  3    to  FIG.  6    are schematic diagrams of sensing units according to some embodiments of the present disclosure. 
         FIG.  7    is a cross-sectional view schematic diagram of a flexible electronic device according to a second embodiment of the present disclosure. 
         FIG.  8    is a three-dimensional schematic diagram of the flexible electronic device according to the second embodiment of the present disclosure. 
         FIG.  9    is a cross-sectional view schematic diagram of a flexible electronic device according to a third embodiment of the present disclosure. 
         FIG.  10    is a cross-sectional view schematic diagram of a flexible electronic device according to a fourth embodiment of the present disclosure. 
         FIG.  11    is a top-view schematic diagram of a portion of a flexible electronic device according to a fifth embodiment of the present disclosure. 
         FIG.  12    is a cross-sectional view schematic diagram corresponding to the section line A-A′ of  FIG.  11   . 
         FIG.  13    is a top-view schematic diagram of a flexible electronic device according to a sixth embodiment of the present disclosure. 
         FIG.  14    is a top-view schematic diagram of a flexible electronic device according to a seventh embodiment of the present disclosure. 
         FIG.  15    is a cross-sectional view schematic diagram of a flexible electronic device according to an eighth embodiment of the present disclosure. 
         FIG.  16    is a cross-sectional view schematic diagram of a flexible electronic device according to a ninth embodiment of the present disclosure. 
         FIG.  17    is a cross-sectional view schematic diagram of a flexible electronic device according to a tenth embodiment of the present disclosure. 
         FIG.  18    is a cross-sectional view schematic diagram of a flexible electronic device according to an eleventh embodiment of the present disclosure. 
         FIG.  19    is a cross-sectional view schematic diagram of a flexible electronic device according to a twelfth embodiment of the present disclosure. 
         FIG.  20    is a cross-sectional view schematic diagram of a flexible electronic device according to a thirteenth embodiment of the present disclosure. 
         FIG.  21    is a cross-sectional view schematic diagram of a flexible electronic device according to a fourteenth embodiment of the present disclosure. 
         FIG.  22    is a top-view schematic diagram of a vibrator substrate according to the fourteenth embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure may be understood by reference to the following detailed description, taken in conjunction with the drawings as described below. It is noted that, for purposes of illustrative clarity and being easily understood by the readers, various drawings of this disclosure show a portion of the electronic device, and certain elements in various drawings may not be drawn to scale. In addition, the number and dimension of each element shown in drawings are only illustrative and are not intended to limit the scope of the present disclosure. 
     Certain terms are used throughout the description and following claims to refer to particular components. As one skilled in the art will understand, electronic equipment manufacturers may refer to a component by different names. This document does not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms “include” and “comprise” are used in an open-ended fashion, and thus should be interpreted to mean “include, but not limited to . . . ”. 
     The directional terms mentioned in this document, such as “up”, “down”, “front”, “back”, “left”, “right”, etc., are only directions referring to the drawings. Therefore, the directional terms used are for illustration, not for limitation of the present disclosure. In the drawings, each drawing shows the general characteristics of methods, structures and/or materials used in specific embodiments. However, these drawings should not be interpreted as defining or limiting the scope or nature covered by these embodiments. For example, the relative size, thickness and position of each layer, region and/or structure may be reduced or enlarged for clarity. 
     It should be understood that when an element or layer is referred to as being “on”, “disposed on” or “connected to” another element or layer, it may be directly on or directly connected to the other element or layer, or intervening elements or layers may be presented (indirect condition). In contrast, when an element is referred to as being “directly on”, “directly disposed on” or “directly connected to” another element or layer, there are no intervening elements or layers presented. In addition, the arrangement relationship between different elements may be interpreted according to the contents of the drawings. 
     The terms “about”, “equal”, “identical” or “the same”, and “substantially” or “approximately” mentioned in this document generally mean being within 20% of a given value or range, or being within 10%, 5%, 3%, 2%, 1% or 0.5% of a given value or range. 
     Although terms such as first, second, third, etc., may be used to describe diverse constituent elements, such constituent elements are not limited by the terms. The terms are used only to discriminate a constituent element from other constituent elements in the specification. The claims may not use the same terms, but instead may use the terms first, second, third, etc. with respect to the order in which an element is claimed. Accordingly, in the following description, a first constituent element may be a second constituent element in a claim. 
     It should be noted that the technical features in different embodiments described in the following can be replaced, recombined, or mixed with one another to constitute another embodiment without departing from the spirit of the present disclosure. 
     The electronic device of the present disclosure may include a display device, a backlight device, an antenna device, a sensing device or a tiled device, but not limited herein. The electronic device may include a bendable, flexible or rollable electronic device. The display device may include a non-self-emissive display device or a self-emissive display device, but not limited herein. The antenna device may include a liquid crystal antenna device or an antenna device without liquid crystal, and the sensing device may include a sensing device used for sensing capacitance, light, heat, pressure, electromagnetic waves or ultrasonic waves, but not limited herein. 
     Electronic elements or electronic units may include passive elements and active elements, such as capacitors, resistors, inductors, diodes, transistors, light-emitting elements, etc. The diodes may include light-emitting diodes or a photodiodes, but not limited herein. The light-emitting elements may be light-emitting diodes. The light-emitting diodes may include, for example, organic light-emitting diodes (OLEDs), inorganic light-emitting diodes or a combination thereof. The inorganic light-emitting diodes may be mini light-emitting diodes (mini LEDs), micro light-emitting diodes (micro LEDs), or quantum dot light-emitting diodes (quantum dot LEDs), but not limited herein. The tiled device may be, for example, a display tiled device or an antenna tiled device, but not limited herein. It should be noted that the electronic device may be any arrangement and combination of the above, but not limited herein. 
     A direction X (a first direction), a direction Y (a second direction) and a direction Z (a third direction) are labeled in the following drawings. The direction Z may be a normal direction or a top-view direction, the direction X and the direction Y may be horizontal directions and perpendicular to the direction Z, and the direction X may be perpendicular to the direction Y, but not limited herein. The following drawings may describe the spatial relationship of structures according the direction X, the direction Y and the direction Z. 
     Please refer to  FIG.  1    and  FIG.  2   .  FIG.  1    is a cross-sectional view schematic diagram of a flexible electronic device according to a first embodiment of the present disclosure.  FIG.  2    is a three-dimensional schematic diagram of the flexible electronic device according to the first embodiment of the present disclosure. The flexible electronic device  10  may include a protruding unit  100 , a flexible substrate  102  and a plurality of sensing units  104 , but not limited herein. The flexible substrate  102  may be disposed on the protruding unit  100  and have a deformation region  106 , and the deformation region  106  may correspond to the protruding unit  100 . For example, the deformation region  106  is capable of being stuck out by the protruding unit  100 , but not limited herein. In some embodiments, the cross-sectional shape of the protruding unit  100  may be rectangular, but not limited herein. The protruding unit  100  may have different shapes according to different designs. As shown in  FIG.  1    and  FIG.  2   , the sensing units  104  may be disposed on the flexible substrate  102 , and at least one of the sensing units  104  may be overlapped with the deformation region  106  in the direction Z. 
     In some embodiments, a ratio of an area of the deformation region  106  to an area of one of the sensing units  104  may be within a suitable range, for example, greater than or equal to 1.4 and less than or equal to  2222 , but not limited herein. Thus, through the design of the appropriate proportion for the area of the deformation region  106  of the flexible substrate  102  and the area of the sensing unit  104  disposed on the flexible substrate  102 , the sensing units  104  may not be easily damaged by the deformation of the flexible substrate  102  when the flexible substrate  102  is deformed by the protruding unit  100  and also provide a good sensing effect, thereby improving the user experience and reliability of the flexible electronic device  10 . For example, the sensing unit  104  may correctly sense the touch when the user&#39;s finger touches the deformation region  106 . 
     As shown in  FIG.  2   , in some embodiments, the area of the deformation region  106  may be greater than or equal to 26 square millimeters and less than half of the area of the flexible substrate  102 , so that the user experience and reliability of the flexible electronic device  10  may be improved. In some embodiments, the area of the deformation region  106  may be less than 26 square millimeters, and the stress generated by the deformation may be too large, which may cause the wires or other electronic elements on the flexible substrate  102  to be easily damaged. In some embodiments, the area of the deformation region  106  may be greater than half of the area of the flexible substrate  102 , and the effect of deformation may be poor, which may make the user&#39;s finger feel the deformation region  106  less easily. However, in the present disclosure, the design of size described above may still be adopted according to practical requirements. 
     A method of defining the area of the deformation region  106  described above may be interpreted through  FIG.  1   . In  FIG.  1   , the flexible electronic device  10  may include a panel  108 , and the panel  108  may include a flexible substrate  102  and a sensing unit  104 , but the present disclosure is not limited herein. A height H 1  exists between the highest point N 1  of an upper surface of the panel  108  and the lowest point N 2  of the upper surface of the panel  108  in the direction Z when the deformation region  106  is stuck out by the protruding unit  100 . The upper surface of the panel  108  in  FIG.  1    is indicated by an upper surface of the sensing unit  104 , but the present disclosure is not limited herein. 
     Then, a height H 2  may be calculated. The height H 2  is 0.9 times the height H 1  (i.e. H 2 =0.9H 1 ), and the height H 2  may be measured upward from the lowest point N 2  of the upper surface of the panel  108  in the direction Z. In  FIG.  1   , the position of the height H 2  is indicated by a line D 1 . The line D 1  may be a virtual straight line parallel to the direction X, and a range R 1  may be defined by the intersections of the line D 1  and the upper surface of the panel  108 . An area of the projection of the flexible substrate  102  within the range R 1  on a plane parallel to the direction X (e.g., a XY-plane, which is a plane defined by the direction X (the first direction) and the direction Y (the second direction)) may be defined as the area of the deformation region  106  of the flexible substrate  102 . The deformation region  106  is also shown in  FIG.  2   . In addition, the definition of the area of the deformation region  106  described above may be applied to other embodiments of the present disclosure. 
     In addition, in some embodiments, the height H 1  may be greater than or equal to 0.5 millimeters (mm) and less than or equal to 50 mm (i.e., 0.5 mm&lt;H 1 &lt;50 mm), so that the user experience and reliability of the flexible electronic device  10  may be improved. In some embodiments, the height H 1  may be greater than 50 mm, and the stress generated by the deformation may be too large, which may cause the wires or other electronic elements on the flexible substrate  102  to be easily damaged. In some embodiments, the height H 1  may be less than 0.5 mm, and the effect of deformation may be poor, which may make the user&#39;s finger feel the deformation region  106  less easily. However, in the present disclosure, the design of size described above may still be made according to practical requirements. 
     In some embodiments, a portion of one of the sensing units  104  may be overlapped with the deformation region  106 , but not limited herein. In some embodiments, one of the sensing units  104  may be completely overlapped with the deformation region  106 , but not limited herein. In some embodiments, the sensing units  104  are capable of sensing a touch, but not limited herein. In some embodiments, the sensing units  104  may sense biometric characteristics such as fingerprints, but not limited herein. 
     In some embodiments, the area of the deformation region  106  may be greater than or equal to 26.01 square millimeters and less than or equal to 10000 square millimeters. Additionally, among at least one of the sensing units  104  overlapped with the deformation region  106 , the area of one of the sensing units  104  may be greater than or equal to 4.5 square millimeters and less than or equal to 18 square millimeters. 
     In some embodiments, the sensing units  104  may include capacitance sensors, pressure sensors, electromagnetic sensors, optical sensors or a combination of the capacitance sensors, the pressure sensors, the electromagnetic sensors and the optical sensors. In some embodiments, the plurality of sensing units  104  in the flexible electronic device  10  may be a plurality of sensors of the same type described above, such as a plurality of capacitance sensors. In some embodiments, the plurality of sensing units  104  in the flexible electronic device  10  may be a plurality of sensors of different types described above, such as a plurality of capacitance sensors and a plurality of optical sensors. 
     In some embodiments, the sensing unit  104  may be the smallest unit capable of conducting sensing. Please refer to  FIG.  3    to  FIG.  6   , which are schematic diagrams of sensing units according to some embodiments of the present disclosure. As shown in  FIG.  3    and  FIG.  4   , the sensing units  104  may include capacitance sensors, but not limited herein. In some embodiments, the capacitance sensors may be used as touch sensors and include self-sensing or mutual-sensing touch sensors, but not limited herein. As shown in  FIG.  3   , in some embodiments, a plurality of sensing electrode series Tx and a plurality of sensing electrode series Rx may constitute a plurality of capacitance sensors  104 , but not limited herein. One of the sensing electrode series Tx may include a plurality of sensing electrodes  110  arranged along the direction X and electrically connected to each other. One of the sensing electrode series Rx may include a plurality of sensing electrodes  112  and a plurality of bridging electrodes  114 , the sensing electrodes  112  may be arranged along the direction Y, and two adjacent sensing electrodes  112  may be electrically connected to each other through one bridging electrode  114 . The sensing electrodes  110  and the sensing electrodes  112  may include transparent conductive materials, but not limited herein. As shown in  FIG.  3   , one of the sensing electrodes  110  or one of the sensing electrodes  112  may be used as one sensing unit (capacitance sensor)  104 , so an area of one sensing unit  104  may be an area of one sensing electrode  110  or an area of one sensing electrode  112 , but not limited herein. 
     As shown in  FIG.  4   , in some embodiments, a plurality of sensing electrodes  116  and a plurality of sensing electrodes  118  are disposed on the flexible substrate  102  and electrically insulated from each other to constitute a plurality of capacitance sensors, but not limited herein. The sensing electrodes  116  may extend in the direction X, and the sensing electrodes  118  may extend along the direction. The sensing electrodes  116  may intersect the sensing electrodes  118 , and a portion that the sensing electrode  116  is overlapped with the sensing electrode  118  may be used as one sensing unit (capacitance sensor)  104 , so an area of one sensing unit  104  may be an area of the portion that the sensing electrode  116  is overlapped with the sensing electrode  118 , but not limited herein. In addition, the sensing electrodes  116  may intersect the sensing electrodes  118  to form a plurality of openings  120 , and the flexible electronic device  10  may include a plurality of light-emitting elements  122  disposed in the openings  120 , but not limited herein. The type of the light-emitting elements  122  may be referred to the previous paragraphs, and will not be described redundantly. 
     In some embodiments, the sensing units  104  may include optical sensors, but not limited herein. As shown in  FIG.  5   , the flexible electronic device  10  may include at least one light-emitting element  124  and at least one optical sensor  126  disposed on the flexible substrate  102 . The type of the light-emitting elements  124  may be referred to the previous paragraphs, and will not be described redundantly. As shown in  FIG.  5   , the light-emitting element  124  may include an inorganic light-emitting diode, such as a light-emitting diode, but not limited herein. The optical sensor  126  may include a photodiode, such as a PIN photodiode, but not limited herein. In some embodiments, one optical sensor  126  may be used as one sensing unit  104 , and an area of one sensing unit  104  may be an area of one optical sensor  126  viewed from the direction Z, but not limited herein. The flexible electronic device  10  may further include at least one thin film transistor  128  and at least one thin film transistor  130 . The thin film transistor  128  may be disposed between the light-emitting element  124  and the flexible substrate  102 , and the thin film transistor  130  may be disposed between the optical sensor  126  and the flexible substrate  102 . The thin film transistor  128  may be electrically connected to the light-emitting element  124 , and the thin film transistor  130  may be electrically connected to the optical sensor  126 , but not limited herein. 
     In some embodiments, the sensing units  104  may include pressure sensors, but not limited herein. As shown in  FIG.  6   , the pressure sensor may include a piezoelectric material layer  132 , an insulating layer  134 , an insulating layer  136 , a plurality of electrodes  138  and a plurality of electrodes  140 , but not limited herein. The piezoelectric material layer  132  may be disposed between the plurality of electrodes  138  and the plurality of electrodes  140 . The piezoelectric material layer  132  may be disposed between the insulating layer  134  and the insulating layer  136 , the electrodes  138  may be disposed between the piezoelectric material layer  132  and the insulating layer  134 , and the electrodes  140  may be disposed between the piezoelectric material layer  132  and the insulating layer  136 . In addition, the electrode  140  may be overlapped with the electrode  138  in the direction Z, but not limited herein. In some embodiments, one electrode  140  or one electrode  138  may be used as one sensing unit  104 , and an area of one sensing unit  104  may be an area of one electrode  140  or an area of one electrode  138  viewed from the direction Z, but not limited herein. In other embodiments, the sensing units  104  may include electromagnetic sensors, but not limited herein. 
     Please refer to  FIG.  1   . The flexible substrate  102  may have an inclined side  102   i,  and an included angle a may exist between the inclined side  102   i  and a horizontal direction (e.g., the direction X). In some embodiments, a length of the inclined side  102   i  may be greater than or equal to 0.53 mm and less than or equal to 2.87 mm, the included angle a may be greater than or equal to 10 degrees and less than or equal to 70 degrees, and the number of the sensing units  104  disposed on the inclined side  102   i  may be greater than or equal to 0.2 and less than or equal to 1.9, so that the user experience and reliability of the flexible electronic device  10  may be improved, but not limited herein. 
     In some embodiments, the length of the inclined side  102   i  may be less than 0.53 mm or the included angle a may be greater than 70 degrees, and the number of the sensing units  104  may be less than 0.2, which may cause the sensing units  104  on the inclined side  102   i  to be easily damaged. In some embodiments, the length of the inclined side  102   i  may be greater than 2.87 mm or the included angle a may be less than 10 degrees, and the number of the sensing units  104  may be greater than 1.9, so that the deformation effect may be poor, which may make the user&#39;s finger feel the deformation region  106  less easily. However, in the present disclosure, the design of size described above may still be made according to practical requirements. 
     In some embodiments, the flexible substrate  102  may be a complete substrate without an opening disposed therein (as shown in  FIG.  1   ), but not limited herein. In other embodiments, the flexible substrate  102  may have an opening disposed therein (as shown  FIG.  11   , etc.), but not limited herein. The flexible substrate  102  may include flexible or stretchable materials. For example, the flexible substrate  102  may include a polymer material, such as polyimide (PI), polyethylene terephthalate (PET), other suitable materials or a combination of the above materials, but not limited herein. The flexible substrate  102  may be a substrate used for carrying the sensing units  104  and may not include the circuit layer above it, but not limited herein. 
     In some embodiments, the protruding unit  100  may include an actuator, and the actuator is configured to provide haptic feedback, but not limited herein. For example, the protruding unit  100  of  FIG.  1    may be stuck out in the direction Z by the actuator to generate haptic feedback, and the deformation region  106  is capable of being stuck out by the protruding unit  100 , but not limited herein. The actuator may include a motor or other elements capable of generating vibration, but not limited herein. 
     According to some embodiments, the protruding unit  100  may be an actuator as an example for illustration. For example, the flexible substrate  102  is not stuck out by the actuator (protruding unit  100 ) when the actuator is not started, so the flexible substrate  102  may be flat at this time. The flexible substrate  102  may be stuck out by the actuator (protruding unit  100 ) when the actuator is started, so that the flexible substrate  102  forms the deformation region  106 , but not limited herein. In other words, the portion of the flexible substrate  102  that is stuck out by the protruding unit  100  is the deformation region  106 . In other embodiments, the position of the protruding unit  100  may be designed to be fixed, and the protruding unit  100  does not need to be started. That is to say, the flexible substrate  102  is stuck out by the protruding unit  100  to form the deformation region  106  when the flexible substrate  102  is initially disposed on the protruding unit  100 , but not limited herein. 
     According to some embodiments, a portion of the flexible substrate  102  can be stuck out by the protruding unit  100 , and the user may easily touch and feel the protruding portion of the flexible substrate  102 . Therefore, the sensing unit  104  corresponding to the protruding unit  100  may be easily touched, thereby enhancing the correctness of sensing. 
     Other embodiments of the present disclosure will be disclosed in the following. In order to simplify the illustration, the same elements in the following would be labeled with the same symbol. For clearly showing the differences between various embodiments, the differences between different embodiments are described in detail below, and repeated features will not be described redundantly. In order to highlight the relevant features of other elements in the flexible electronic device  10 , the sensing units  104  in the flexible electronic device  10  may be omitted in the following drawings (as shown in  FIG.  7   , etc.). However, the flexible electronic device  10  in the following drawings may still include the sensing units  104  in the flexible electronic device  10  of the first embodiment, and the functions that the flexible electronic devices of the following embodiments may achieve may be referred to the functions of the first embodiment described above, which will not be described redundantly herein. 
     Please refer to  FIG.  7    and  FIG.  8   .  FIG.  7    is a cross-sectional view schematic diagram of a flexible electronic device according to a second embodiment of the present disclosure.  FIG.  8    is a three-dimensional schematic diagram of the flexible electronic device according to the second embodiment of the present disclosure. In some embodiments, the flexible electronic device  10  may include a plurality of protruding units, such as a protruding unit  100  and a protruding unit  200 , but not limited herein. As shown in  FIG.  7   , the cross-sectional shapes of the protruding unit  100  and the protruding unit  200  may be bullet-shaped, but not limited herein. In some embodiments, the protruding unit  100  and the protruding unit  200  may have different shapes or sizes. 
     Another method of defining the area of the deformation region  106  may be interpreted through  FIG.  7   . Taking the protruding unit  100  as an example, a height H 1  exists between the highest point N 3  of a lower surface of the panel  108  and the lowest point N 4  of the lower surface of the panel  108  in the direction Z when the deformation region  106  is stuck out by the protruding unit  100 . The lower surface of the panel  108  in  FIG.  7    is indicated by a lower surface of the flexible substrate  102 , but the present disclosure is not limited herein. 
     Then, a height H 2  may be calculated. The height H 2  is 0.9 times the height H 1  (i.e. H 2 =0.9H 1 ), and the height H 2  may be measured upward from the lowest point N 4  of the lower surface of the panel  108  in the direction Z. In  FIG.  7   , the position of the height H 2  is indicated by a line D 2 . The line D 2  may be a virtual straight line parallel to the direction X, and a range R 2  may be defined by the intersections of the line D 2  and the lower surface of the panel  108 . An area of the projection of the flexible substrate  102  within the range R 2  on a plane parallel to the direction X (e.g., a XY-plane, which is a plane defined by the direction X and the direction Y) may be defined as the area of the deformation region  106  of the flexible substrate  102 . The deformation region  106  is also shown in  FIG.  8   . In addition, the definition of the area of the deformation region  106  described above may be applied to other embodiments of the present disclosure. 
     As shown in  FIG.  7    and  FIG.  8   , the flexible electronic device  10  may further include a plurality of electronic units  142  disposed on the flexible substrate  102 . According to some embodiments, a ratio of the area of the deformation region  106  to an area of one of the plurality of electronic units  142  may be greater than or equal to 53.08 and less than or equal to 1000000, but not limited herein. 
     According to some embodiments, the electronic unit  142  may be a display unit. According to some embodiments, the electronic unit  142  may be a non-display unit with no display function. For convenience of illustration, the electronic unit  142  is a display unit  142  as an example for illustration in the following. The flexible electronic device  10  may include the panel  108 , and the panel  108  may include the flexible substrate  102 , a plurality of display units  142  and a plurality of sensing units  104  (not shown in  FIG.  7   ), but the present disclosure is not limited herein. In addition, at least one of the plurality of display units  142  may be overlapped with the deformation region  106 . For example, the least one of the plurality of display units  142  may be overlapped with the deformation region in the direction Z. In some embodiments, a portion of one of the display units  142  may be overlapped with the deformation region  106 , but not limited herein. In some embodiments, one of the display units  142  may be completely overlapped with the deformation region  106 , but not limited herein. 
     For convenience of illustration, merely a plurality of display units  142  are shown on the flexible substrate  120  in  FIG.  7   . However, it should be understood that a plurality of sensing units  104  may also be disposed on the flexible substrate  120 , as shown in  FIG.  1   . According to some embodiments, as shown in  FIG.  8   , a plurality of display units  142  and a plurality of sensing units  104  may be disposed on the flexible substrate  102 . For convenience of illustration, the small squares shown in  FIG.  8    may indicate the plurality of display units  142  and the plurality of sensing units  104 . The number of the display units  142  and the number of the sensing units  104  are not limited. The number of the display units  142  may be the same as or different from the number of the sensing units  104  within a given area. For example, according to some embodiments, the number of the display units  142  may be greater than the number of the sensing units  104 . The area of the display unit  142  and the area of the sensing unit  104  are not limited and may be the same or different. For example, according to some embodiments, the area of the display unit  142  may be less than the area of the sensing unit  104 . For example, according to some embodiments, the area of the display unit  142  may be greater than the area of the sensing unit  104 . 
     In some embodiments, the area of the deformation region  106  may be greater than or equal to 26.01 square millimeters and less than or equal to 10000 square millimeters. Among at least one of the display units  142  overlapped with the deformation region  106 , the area of one of the display units  142  may be greater than or equal to 0.01 square millimeters and less than or equal to 0.49 square millimeters. Furthermore, a ratio of the area of the deformation region  106  to the area of one of the plurality of display units  142  may be greater than or equal to 53.08 and less than or equal to 1000000, but not limited herein. In some embodiments, the amount of the display units  142  included in the area of the smallest deformation region  106  may be at least 53.08, and the display units  142  may be less easily to be damaged by the stress generated by the deformation. 
     In some embodiments, a display unit  142  may be a pixel, and a pixel may include a plurality of sub-pixels. One pixel may include sub-pixels of different colors, such as including red sub-pixels, green sub-pixels and blue sub-pixels, but not limited herein. In the condition that the flexible electronic device  10  is an organic light-emitting diode display device, the sub-pixel may include an anode, an organic light emitting layer and a portion of a cathode. In the condition that the flexible electronic device  10  is an inorganic light-emitting diode display device, the sub-pixel may include a light-emitting element, such as a light-emitting diode. The type of the light-emitting element may be referred to the paragraphs above, but not limited herein. In the condition that the flexible electronic device  10  is a liquid crystal display device, the sub-pixel may include a pixel electrode, a portion of liquid crystal and a portion of a common electrode. 
     According to some embodiments, for example, one display unit  142  may include a rectangular region, an area of this rectangular region may be the product of two sides perpendicular to each other, one of the sides may be a pitch between one sub-pixel and the next sub-pixel of the same color in a direction, and the other of the sides may be a pitch between the sub-pixel and the next sub-pixel of the same color in another direction. The two directions described above may be perpendicular to each other, and the area of this rectangular region may be used as the area of the display unit  142 , but not limited herein. 
     As shown in  FIG.  8   , the protruding unit  100  and the protruding unit  200  may be disposed along a direction (e.g., the direction X). The protruding unit  100  and the protruding unit  200  may have a pitch P 1  in the direction X, the flexible substrate  102  may have a length P 2  in the direction X, and the pitch P 1  may be greater than or equal to 3 centimeters (cm) and less than or equal to 0.8 times of the length P 2 , so that the user experience of the flexible electronic device  10  may be improved, but not limited herein. In some embodiments, the pitch P 1  may be less than 3 cm, and the deformations of the protruding unit  100  and the protruding unit  200  may be more easily interfered with each other. In some embodiments, the pitch P 1  may be greater than 0.8 times of the length P 2 , and the deformation effect of the protruding unit  100  and the protruding unit  200  may be poor. However, in the present disclosure, the design of size described above may still be made according to practical requirements. 
     Please refer to  FIG.  9   , which is a cross-sectional view schematic diagram of a flexible electronic device according to a third embodiment of the present disclosure. In some embodiments, the cross-sectional shape of the protruding unit  100  may be rectangular, and the display units  142  are disposed on the flexible substrate  102 , but not limited herein. An upper surface of the display unit  142  in  FIG.  9    may be used as an upper surface of the panel  108 , and a height H 1  exists between the highest point of the upper surface of the display unit  142  and the lowest point of the upper surface of the display unit  142  in the direction Z. A height H 2  may be measured upward from the lowest point of the upper surface of the display unit  142  in the direction Z, but the present disclosure is not limited herein. The definition of the deformation region  106  in  FIG.  9    is the same as definition of the deformation region  106  in  FIG.  1    in the first embodiment, which may be referred to the above description, and will not be described redundantly herein. 
     In some embodiments, a length of the inclined side  102   i  may be greater than or equal to 0.53 mm and less than or equal to 2.87 mm, but not limited herein. A length L 1  of the display unit  142  may be, for example, about 0.115 mm when the display unit  142  has a smaller size, but not limited herein. The length L 1  of the display unit  142  may be, for example, about 0.628 mm when the display unit  142  has a larger size, but not limited herein. Therefore, the number of the display units  142  disposed on the inclined side  102   i  may be greater than or equal to 0.8 and less than or equal to 25, so that the user experience and reliability of the flexible electronic device  10  may be improved, but not limited herein. 
     In some embodiment, the length of the inclined side  102   i  may be less than 0.53 mm or the included angle a may be greater than 70 degrees, and the number of the display units  142  may be less than 0.8, which may cause the display units  142  on the inclined side  102   i  to be easily damaged. In some embodiments, the length of the inclined side  102   i  may be greater than 2.87 mm or the included angle a may be less than 10 degrees, and the number of the display units  142  may be greater than 25, resulting in the deformation effect may be poor at this time, which may make the user&#39;s finger feel the deformation region  106  less easily. However, in the present disclosure, the design of size described above may still be made according to practical requirements. 
     In some embodiments, the flexible electronic device  10  may include a central region Q 1  and a plurality of side regions Q 3 . As shown in  FIG.  9   , the central region Q 1  may be disposed between two side regions Q 3  in the direction X, but not limited herein. The side region Q 3  may include a curved portion of the flexible substrate  102 , a portion of a flat portion adjacent to the curved portion and display units  142  disposed on the above portions, and the central region Q 1  may include the remaining portion of the flat portion of the flexible substrate  102  and display units  142  disposed on this portion, but not limited herein. The display units  142  in the central region Q 1  may be turned on, and the display units  142  in the side regions Q 3  may be turned off, so that the range that emits light may be smaller than the protruding range. Therefore, the display units  142  in the side regions Q 3  may be prevented from causing halo due to different viewing angles of emitted light. 
     In some embodiments, the flexible electronic device  10  may include a central region Q 2  and a plurality of side regions Q 4 . As shown in  FIG.  9   , the central region Q 2  may be disposed between two side regions Q 4  in the direction X, but not limited herein. The side region Q 4  may include a curved portion of the flexible substrate  102  and display units  142  disposed on this portion, and the central region Q 2  may include a flat portion of the flexible substrate  102  and display units  142  disposed on this portion, but not limited herein. The display units  142  in the central region Q 2  may be turned off, and the display units  142  in the side regions Q 4  may be turned on, so that the edge of the protruding range emits light. Therefore, when the flexible electronic device  10  is used as a button, the range of the button may be highlighted in an annular shape, but not limited herein. 
     Please refer to  FIG.  10   , which is a cross-sectional view schematic diagram of a flexible electronic device according to a fourth embodiment of the present disclosure. The protruding unit  100  of the present disclosure may have different shapes according to different designs. For example, in some embodiments, a protruding unit  100  may include a portion  100   a  and a portion  100   b,  and the portion  100   a  may be disposed on the portion  100   b  in the direction Z, but not limited herein. The portion  100   a  may have a width Wa in the direction X, the portion  100   b  may have a width Wb in the direction X, and the width Wa may be different from the width Wb. For example, the width Wb may be greater than the width Wa, but not limited herein. 
     Please refer to  FIG.  11    and  FIG.  12   .  FIG.  11    is a top-view schematic diagram of a portion of a flexible electronic device according to a fifth embodiment of the present disclosure.  FIG.  12    is a cross-sectional view schematic diagram corresponding to the section line A-A′ of  FIG.  11   . In some embodiments, the flexible substrate  102  may include a patterned substrate. For example, the flexible substrate  102  may include a plurality of main portions  144  and a plurality of connecting portions  146 , and one of the main portions  144  may be disposed between two adjacent connecting portions  146 . According to some embodiments, two adjacent ones of the plurality of main portions  144  are connected to each other. In detail, two adjacent main portions  144  may be connected to each other through one of the connecting portions  146 , but not limited herein. In addition, the flexible substrate  102  may include a plurality of openings  148 , and the openings  148  may be surrounded by the main portions  144  and the connecting portions  146 , but not limited herein. In some embodiments, the entire flexible substrate  102  may be patterned to have a plurality of openings  148 , a plurality of main portions  144  and a plurality of connecting portions  146 , but not limited herein. In the flexible substrate  102  of some embodiments, the openings  148  of different shapes and sizes may be designed according to requirements. 
     In addition, the deformation region  106  may include at least one of the plurality of main portions  144 . In some embodiments, as shown in  FIG.  11   , the deformation region  106  may include a plurality of main portions  144 . In the flexible substrate  102 , the range of one main portion  144  may be a unit that the display unit  142  is disposed on, and the openings  148  adjacent to the main portion  144  may define the boundary of the main portion  144 . For example, in the flexible substrate  102 , a rectangular unit (such as the portion framed by the dotted line in  FIG.  11   ) including the display unit  142  may be the range of the main portion  144 , and the openings  148  adjacent to the main portion  144  may define the boundary of the main portion  144 . For example, at least one side or at least one corner of the rectangular unit may intersect the boundary of the corresponding opening  148 . For example, as shown in  FIG.  11   , three sides of the rectangular unit framed by dotted line intersect the boundaries of the corresponding three openings  148 , but the present disclosure is not limited herein. Therefore, in some embodiments, an area of one main portion  144  may be an area of the rectangular unit on the flexible substrate  102  that the display unit  142  is disposed on, and the boundary of the rectangular unit may be defined by the corresponding openings  148 . 
     In some embodiments, an area of the deformation region  106  may be greater than or equal to 26.01 square millimeters and less than or equal to 10000 square millimeters. An area of one of the plurality of main portions  144  may be greater than or equal to 0.02 square millimeters and less than or equal to 1 square millimeter. In some embodiments, a ratio of the area of the deformation region  106  to the area of one of the plurality of main portions  144  may be greater than or equal to 26.01 and less than or equal to 500000, but not limited herein. Thus, the display units  142  are not easily damaged by the stress generated by the deformation when the flexible substrate  102  is deformed (e.g., when the flexible substrate  102  is stuck out by the protruding unit). Furthermore, the sensing units  104  are not easily damaged by the stress generated by deformation and may correctly sense. When the flexible substrate  102  is stuck out by the protruding unit  100  to form the deformation region  106 , the following conditions may occur: the shape and/or the size of the openings  148  may be changed, the relative positions of the main portions  144  may be changed, the connecting portions  146  may be elongated, or a combination of the above conditions may occur, but not limited herein. 
     In some embodiments, one or plural display units  142  may be disposed on one main portion  144 . As shown in  FIG.  11   , one display unit  142  may be disposed on one main portion  144 , but not limited herein. No display unit  142  is disposed on the connecting portion  146 . The sensing units  104  are not shown in  FIG.  11    and  FIG.  12   , but one or plural sensing units  104  or at least a portion of one sensing unit  104  may be disposed on one of the main portions  144 . 
     The structure of one sub-pixel in the display unit  142  on the main portion  144  is illustrated, for example, in the following, but the present disclosure is not limited herein.  FIG.  12    is a cross-sectional view schematic diagram corresponding to the section line A-A′ of  FIG.  11   , which shows the structures on two main portions  144 . The display unit  142  may include a plurality of sub-pixels, such as three sub-pixels.  FIG.  12    merely shows the structure of one sub-pixel in the display unit  142  respectively on two main portions  144 . The display unit  142  may include a light-emitting element  154  and a driving element  152 . The driving element  152  may be electrically connected to the light-emitting element  154 . For example, the driving element  152  may be a thin film transistor. 
     The structure on the main portion  144  is detailed in the following. A buffer layer  150  may be disposed on the main portion  144 , and a thin film transistor  152  may be disposed on the buffer layer  150 . The thin film transistor  152  may include a gate GE, a source SE, a drain DE and a semiconductor layer SC. The semiconductor layer SC may be disposed on the buffer layer  150 , an insulating layer IN 1  may be disposed on the semiconductor layer SC, the gate GE may be disposed on the insulating layer IN 1 , and an insulating layer IN 2  may be disposed on the gate GE. The source SE and the drain DE may be disposed on the insulating layer IN 2  and electrically connected to the semiconductor layer SC. An insulating layer IN 3  may be disposed on the source SE and the drain DE, and the light-emitting element  154  may be disposed on the insulating layer IN 3 . 
     The light-emitting elements  154  in  FIG.  12    may be light-emitting diodes as an example, but the present disclosure is not limited herein. The light-emitting element  154  may include a first electrode  156 , a second electrode  158 , a first semiconductor layer  160 , a light-emitting layer  162  and a second semiconductor layer  164 . The light-emitting layer  162  may be, for example, a multiple quantum well (MQW) layer, but not limited herein. The first electrode  156  may be electrically connected to a common electrode (not shown) through a bonding pad  166 . The second electrode  158  may be electrically connected to the drain DE through a bonding pad  168 . 
     A pixel definition layer  170  may be disposed on the insulating layer IN 3 , and the light emitting element  154  may be disposed in an opening of the pixel definition layer  170 . A protective layer  172  may cover the light emitting element  154 , and the protective layer  172  may protect the light emitting element  154 , so as to reduce the influence of air or humidity, for example. In addition, an insulating layer IN 4  may be disposed on the protective layer  172 . 
     In some embodiments (as shown in  FIG.  11    and  FIG.  12   ), the flexible electronic device  10  may include a middle substrate  174  disposed between the flexible substrate  102  and the protruding unit  100 , but not limited herein. The middle substrate  174  may include elastic, stretchable or bendable materials, but not limited herein. For example, the middle substrate  174  may include silicone rubber or elastomer, the silicone rubber may include polydimethylsiloxane (PDMS), and the elastomer may include polyurethane (PU) or polytetrafluoroethylene (PTFE), but not limited herein. The middle substrate  174  may reduce the probability of causing damage to the flexible electronic device  10  during deformation. According to some embodiments, an area of the middle substrate  174  may be greater than an area of the protruding unit  100 , and the area of the protruding unit  100  may be greater than an area of the main portion  144 , but not limited herein. 
     Please refer to  FIG.  13   , which is a top-view schematic diagram of a flexible electronic device according to a sixth embodiment of the present disclosure. In some embodiments, the flexible electronic device  10  may include a plurality of protruding units, such as a protruding unit  100  and a protruding unit  200 . The flexible substrate  102  includes a deformation region  106 A and a deformation region  106 B. The deformation region  106 A corresponds to the protruding unit  100 , and the deformation region  106 B corresponds to the protruding unit  200 . An area of the deformation region  106 B may be different from an area of the deformation region  106 A. For example, the area of the deformation region  106 B may be greater than the area of the deformation region  106 A, but not limited herein. In addition, in the direction Z, the number of the main portions  144  corresponding to (or overlapped with) the protruding unit  200  is different from the number of the main portions  144  corresponding to (or overlapped with) the protruding unit  100 . For example, the number of the main portions  144  corresponding to (or overlapped with) the protruding unit  200  may be greater than the number of the main portions  144  corresponding to (or overlapped with) the protruding unit  100 , but not limited herein. 
     Please refer to  FIG.  14   , which is a top-view schematic diagram of a flexible electronic device according to a seventh embodiment of the present disclosure. In order to highlight the features of this embodiment, the middle substrate  174  is omitted in  FIG.  14   . In some embodiments, the flexible substrate  102  may include one or plural patterned portions (such as a patterned portion K 1  and a patterned portion K 2  in  FIG.  14   ). The patterned portion may include openings  148 , main portions  144  and connecting portions  146 . The patterned portion may be correspondingly disposed on the protruding unit  100  in the direction Z, and the number of the patterned portions may be the same as the number of the protruding units  100 , but the number of the patterned portions and the number of the protruding units  100  of the present disclosure are not limited to those in  FIG.  14   . In addition, as shown in  FIG.  14   , a plurality of display units  142  may be disposed on one main portion  144 , but not limited herein. Therefore, a portion of the flexible substrate  102  may be patterned and another portion of the flexible substrate  102  may not be patterned, but not limited herein. 
     Please refer to  FIG.  15   , which is a cross-sectional view schematic diagram of a flexible electronic device according to an eighth embodiment of the present disclosure. In some embodiments, a plurality of display units  142  may be disposed between the flexible substrate  102  and a plurality of sensing units  104  in the direction Z, but not limited herein. The protective layer  172  may include a flat upper surface, and a plurality of sensing electrodes  176  in the sensing unit  104  may be disposed on the upper surface of the protective layer  172 , but not limited herein. In some embodiments, the sensing electrode  176  may be a metal wire in a metal mesh structure, but not limited herein. In some embodiments, a plurality of light-emitting elements  154  may be disposed on one main portion  144 , but not limited herein. 
     The flexible electronic device  10  may further include a plurality of signal lines  178  and a plurality of signal lines  180  disposed on the connecting portion  146 . The signal lines  178  may be disposed on the buffer layer  150 , the insulating layer IN 2  may be disposed on the signal lines  178 , and the signal lines  180  may be disposed on the insulating layer IN 2 , but not limited herein. In addition, the insulating layer IN 4  may include elastic filling materials, but not limited herein. The signal lines  178  and the gate GE in the thin film transistor  152  may be formed by the same layer, and the signal lines  180  and the drain DE in the thin film transistor  152  may be formed by the same layer, but not limited herein. 
     Please refer to  FIG.  16   , which is a cross-sectional view schematic diagram of a flexible electronic device according to a ninth embodiment of the present disclosure. In some embodiments, a plurality of sensing units  104  may be disposed between the flexible substrate  102  and a plurality of display units  142 , but not limited herein. The flexible electronic device  10  may further include an insulating layer IN 5 , and the insulating layer IN 5  may be disposed on the insulating layer IN 3 , but not limited herein. The insulating layer IN 5  may include a flat upper surface, and the sensing electrodes  176  in the sensing unit  104  may be disposed on the upper surface of the insulating layer IN 5 . The sensing electrodes  176  may be disposed on the main portion  144  and the connecting portion  146 , but not limited herein. The flexible electronic device  10  may further include an insulating layer IN 6  disposed on the insulating layer IN 5 . A portion of the sensing electrodes  176  may be disposed between the insulating layer IN 5  and the insulating layer IN 6 , and the light-emitting elements  154  may be disposed on the insulating layer IN 6 , but not limited herein. 
     Please refer to  FIG.  17   , which is a cross-sectional view schematic diagram of a flexible electronic device according to a tenth embodiment of the present disclosure. In some embodiments, the sensing units  104  and the display units  142  may be disposed on opposite sides of the flexible substrate  102  in the direction Z, so that the flexible substrate  102  may be disposed between the sensing units  104  and the display units  142 , but not limited herein. The sensing electrodes  176  in the sensing units  104  may be disposed on the middle substrate  174 , that is, the sensing units  104  may be disposed between the middle substrate  174  and the flexible substrate  102 , but not limited herein. The flexible electronic device  10  may further include an insulating layer IN 7 , and the insulating layer IN 7  may be disposed on the middle substrate  174  and cover the sensing electrodes  176 , but not limited herein. The flexible electronic device  10  may further include an adhesive layer  182  disposed between the flexible substrate  102  and the insulating layer IN 7 , but not limited herein. 
     Please refer to  FIG.  18   , which is a cross-sectional view schematic diagram of a flexible electronic device according to an eleventh embodiment of the present disclosure. In some embodiments, the protruding unit  100  may include a haptic actuator, and the protruding unit  100  may include a substrate  186 , a piezoelectric material layer  188 , an insulating layer  190 , an insulating layer  192 , a plurality of electrodes  194  and a plurality of electrodes  196 , but not limited herein. The piezoelectric material layer  188 , the plurality of electrodes  194  and the plurality of electrodes  196  may be disposed on the substrate  186 . The piezoelectric material layer  188  may be disposed between the plurality of electrodes  194  and the plurality of electrodes  196 . The insulating layer  190  may be disposed on the substrate  186 , the piezoelectric material layer  188  may be disposed on the insulating layer  190 , and the electrodes  194  may be disposed between the piezoelectric material layer  188  and the insulating layer  190 . The insulating layer  192  may be disposed on the piezoelectric material layer  188 , and the electrodes  196  may be disposed between the insulating layer  192  and the piezoelectric material layer  188 . The electrode  196  may be overlapped with the electrode  194  in the direction Z, but not limited herein. 
     In addition, the flexible electronic device  10  may include an adhesive layer  184  disposed between the insulating layer  192  and the middle substrate  174 , so that the protruding unit  100  may be attached to the middle substrate  174  through the adhesive layer  184 , but not limited herein. The protruding unit  100  may be deformed by deforming the piezoelectric material layer  188  via applying voltage through the electrodes  194  and the electrodes  196 . 
     Please refer to  FIG.  19   , which is a cross-sectional view schematic diagram of a flexible electronic device according to a twelfth embodiment of the present disclosure. In some embodiments, the protruding unit  100  may include a haptic actuator, and the protruding unit  100  may include a substrate  186 , a piezoelectric material layer  188 , an electrode  194  and an electrode  196 , but not limited herein. The electrode  194  and the electrode  196  may be disposed on the substrate  186 , and the piezoelectric material layer  188  may be disposed between the electrode  194  and the electrode  196 . The protruding unit  100  may be deformed by deforming the piezoelectric material layer  188  via applying voltage through the electrode  194  and the electrode  196 , and an air gap  198  may be generated between the substrate  186  and the middle substrate  174 , but not limited herein. 
     Please refer to  FIG.  20   , which is a cross-sectional view schematic diagram of a flexible electronic device according to a thirteenth embodiment of the present disclosure. In some embodiments, the flexible electronic device  10  may include a plurality of vibrators, such as a vibrator  2021 , a vibrator  2023  and a vibrator  2025 , but not limited herein. For example, the vibrator  2021  may be disposed between the protruding unit  100  and the flexible substrate  102  in the direction Z. The vibrator  2023  may be disposed on one side Si of the protruding unit  100  in the direction X and not overlapped with the protruding unit  100  in the direction Z. The vibrator  2025  may be disposed on another side S 2  of the protruding unit  100  in the direction X and not overlapped with the protruding unit  100  in the direction Z, but not limited herein. In some embodiments, the flexible electronic device  10  may include one vibrator, such as a vibrator  2021 , but not limited herein. The vibrator may include a vibration motor, but not limited herein. 
     The flexible electronic device  10  may include a plurality of adhesive layers, such as an adhesive layer  2041 , an adhesive layer  2043  and an adhesive layer  2045 , but not limited herein. For example, the adhesive layer  2041  may be disposed between the vibrator  2021  and the flexible substrate  102 , the adhesive layer  2043  may be disposed between the vibrator  2023  and the flexible substrate  102 , and the adhesive layer  2045  may be disposed between the vibrator  2025  and the flexible substrate  102 , but not limited herein. In some embodiments, an adhesive layer (not shown) may be disposed between the vibrator  2021  and the protruding unit  100 , but not limited herein. 
     The protruding unit  100  may include a side  2061  and a side  2063  opposite to the side  2061 , and the flexible electronic device  10  may include a region J 1  and a region J 2 . The side  2061  may be disposed in the region J 1 , the side  2063  may be disposed in the region J 2 , and the vibrator(s) may not be disposed in the region J 1  and/or the region J 2 , so as to prevent the vibrator from being damaged due to the deformation of the protruding unit  100 . That is to say, according to some embodiments, no vibrator is disposed at the positions of both of the side  2061  and the side  2063  of the protruding unit  100  in the direction Z. 
     Please refer to  FIG.  21    and  FIG.  22   .  FIG.  21    is a cross-sectional view schematic diagram of a flexible electronic device according to a fourteenth embodiment of the present disclosure.  FIG.  22    is a top-view schematic diagram of a vibrator substrate according to the fourteenth embodiment of the present disclosure. In some embodiments, the flexible electronic device  10  may include a vibrator substrate  208  and an adhesive layer  210 , but not limited herein. For example, the vibration substrate  208  may be disposed on the display units  142 , and the adhesive layer  210  may be disposed between the vibration substrate  208  and the display units  142 , but not limited herein. The vibration substrate  208  may be disposed on an upper surface of the panel  108 . The upper surface of the panel  108  is indicated by the upper surface of the display unit  142  in  FIG.  21   , but the present disclosure is not limited herein. As shown in  FIG.  22   , a patterned piezoelectric material layer  220  may be disposed on the vibration substrate  208 , and a voltage may be applied to the patterned piezoelectric material layer  220  to generate vibration, but not limited herein. 
     In some embodiments, although not shown in the drawings, a vibration layer (such as a piezoelectric material layer) may be disposed as an entire plane on the upper surface of the panel  108  (or on the display units  142 ). That is to say, the vibration layer may have no pattern. The vibration layer may be formed by a coating process, but not limited herein. In some embodiments, although not shown in the drawings, a plurality of vibration layers may be disposed on the upper surface of the panel  108 . For example, one of the vibration layers may be disposed on one of the light-emitting elements. In some embodiments, although not shown the drawings, one vibration layer may be disposed on one of the main portions  144 , and the vibration layer may be formed by a coating process, but not limited herein. For example, a plurality of vibration layers may be respectively disposed on a plurality of light-emitting elements in the panel  108 . For example, three vibration layers may be respectively disposed on the three light-emitting elements  154  in  FIG.  18   , specifically, disposed on three separate portions of the insulating layer IN 4  on the three light-emitting elements  154  in  FIG.  18   . 
     In the present disclosure, the electrode may include metal, alloy, transparent conductive materials, other suitable conductive materials or a combination of the above materials, but not limited herein. The insulating layer may include inorganic insulating materials, organic insulating materials, other suitable insulating materials or a combination of the above materials, but not limited herein. 
     In some embodiments, the flexible electronic device  10  may be applied in a vehicle. For example, the flexible electronic device  10  may be applied to a steering wheel, a gear shift, a center console, a dashboard, other suitable positions or a combination of the above objects in a vehicle, but not limited herein. 
     From the above description, in the flexible electronic device according the embodiments of the present disclosure, through the design of the appropriate proportion for the area of the deformation region of the flexible substrate and the area of the sensing unit disposed on the flexible substrate, the sensing units may not be easily damaged by the deformation of the flexible substrate when the flexible substrate is deformed by the protruding unit and also provide a good sensing effect, thereby improving the user experience and reliability of the flexible electronic device. 
     Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the disclosure. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.