Patent Publication Number: US-10789886-B2

Title: Display device

Description:
TECHNICAL FIELD 
     The disclosure relates to a display device that includes a deformable display unit having flexibility. 
     BACKGROUND ART 
     PTL 1 discloses a technology to display images, using a deformable display unit having flexibility (for example: Electro Luminescence (EL) Display). Specifically, PTL 1 discloses a display device in which images are displayed on an unrolled part (unrolled area) of a rollable display unit. 
     CITATION LIST 
     Patent Literature 
     
         
         PTL 1: JP 2016-218326 A (published on Dec. 22, 2016). 
       
    
     SUMMARY 
     Technical Problem 
     A rolled part (rolled area) of the display unit has a smaller heat dissipation area than an unrolled area. Thus, when a current flows in the rolled area, the temperature of the rolled area increases, thus deteriorating the display device. 
     Solution to Problem 
     In order to solve the aforementioned problems, a display device of a first aspect of the disclosure includes: a display unit including a plurality of pixel circuits each including an electro-optic element, the display unit being deformable and having flexibility; a rolling mechanism configured to roll the display unit and store a rolled part of the display unit as a rolled area in an interior of the rolling mechanism; a power source circuit; a first voltage primary wiring line configured to supply a first voltage from the power source circuit to at least one of the plurality of pixel circuits; and a second voltage primary wiring line configured to supply a second voltage lower than the first voltage from the power source circuit to at least one of the plurality of pixel circuits, wherein an area of the display unit excluding the rolled area on the display unit includes an unrolled area, and an end portion of the unrolled area of the display unit positioned on an opposite side with respect to the rolling mechanism includes a lowermost edge portion, and at least one of the first voltage primary wiring line and the second voltage primary wiring line is electrically connected to pixel circuits arranged at the lowermost edge portion first, out of the plurality of pixel circuits. 
     Advantageous Effects of Disclosure 
     In accordance with the display device of one aspect of the disclosure, the deterioration of the display device due to an increase in temperature of the rolled area can be prevented. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1A  is a perspective view illustrating a state where a display unit of a display device of a first embodiment is not rolled, and  FIG. 1B  is a perspective view illustrating a state where part of the display unit is rolled. 
         FIG. 2  is a view schematically illustrating a configuration of the display unit of  FIGS. 1A and 1B . 
         FIGS. 3A to 3C  are views for describing a lowermost edge portion provided in the display unit of  FIGS. 1A and 1B . 
         FIG. 4  is a functional block diagram illustrating a configuration of main components of the display device of  FIGS. 1A and 1B . 
         FIG. 5  is a schematic side view of the display device of  FIGS. 1A and 1B , and  FIG. 5B  is an enlarged view of an area DD 1  in  FIG. 5A . 
         FIG. 6  is a view illustrating one example of a pixel circuit corresponding to one pixel in the display unit of  FIGS. 1A and 1B . 
         FIG. 7  is a view for describing a configuration to supply a voltage from a power source circuit to pixel circuits in the display device of  FIGS. 1A and 1B . 
         FIG. 8  is a cross-sectional view schematically illustrating a configuration of electrically connecting a negative electrode and a second voltage primary wiring line in the display device of  FIGS. 1A and 1B . 
         FIG. 9  is a view for describing control of voltage supply from the power source circuit to the power source circuits in the display device of  FIGS. 1A and 1B . 
         FIGS. 10A and 10B  are views illustrating one example of display control with the display device of  FIGS. 1A and 1B . 
         FIG. 11  is a view illustrating one modification of the display device of  FIGS. 1A and 1B  and illustrating another example of the pixel circuit. 
         FIG. 12A  is a schematic side view of the display device as another modification of the display device of  FIGS. 1A and 1B , and  FIG. 12B  is an enlarged view of an area DD 2  in  FIG. 12A . 
         FIG. 13A  is a view schematically illustrating a configuration of a display device of a second embodiment, and  FIG. 13B  is a view schematically illustrating a configuration of a display unit and its periphery in the display device. 
         FIG. 14  is a view illustrating a display device of a third embodiment. 
         FIG. 15  is a view illustrating a modification of the display device of the third embodiment. 
         FIG. 16  is a view illustrating a display device of a fourth embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     First Embodiment 
     Hereinafter, a description follows regarding a first embodiment of the disclosure, with reference to  FIGS. 1A to 10B . In the first embodiment, a display device  1  that includes two display units (for example, EL display) having flexibility is described. Hereinafter, for the convenience of description, the respective two display units are referred to as display units  10   f  and  10   r  to distinguish between the two display units. Further, when it is not required to distinguish between the two display units  10   f  and  10   r , the display units are collectively referred to as display units  10 . 
     Note that various members of the display device  1  are illustrated in respective drawings described below, but the descriptions of members that are not related to the first embodiment are omitted. It is to be understood that the members, of which the descriptions are omitted, are similar to known members. Note that the purpose of the drawings is to schematically describe the shape, structure, and positional relation of each member and are not necessarily illustrated on the actual scale. 
     Overview of Display Device  1   
     First, an overview of the display device  1  will be described with reference to  FIGS. 1A and 1B . The display device  1  includes the display units  10   f  and  10   r , rolling mechanisms  110   f  and  110   r , and protecting members  120   f  and  120   r . Each of the rolling mechanisms  110   f  and  110   r  includes link members  111   f  and  111   r  (for example, pantograph links). The rolling mechanisms  110   f  and  110   r  may be collectively referred to as rolling mechanisms  110  (see  FIG. 4  described later). 
     Note that the rolling mechanism  110   f , the link member  111   f , and the protecting member  120   f  are members provided to the display unit  10   f . Similarly, the rolling mechanism  110   r , the link member  111   r , and the protecting member  120   r  are members provided to the display unit  10   r.    
     In the description below, unless particularly necessary, only the rolling mechanism  110   f , the link member  111   f , and the protecting member  120   f  are described. Respective functions of the rolling mechanism  110   r , the link member  111   r , and the protecting member  120   r  are similar to those of the rolling mechanism  110   f , the link member  111   f , and the protecting member  120   f , and thus their descriptions are omitted. In this respect, the same goes for other members with the same subscripts “f” and “r” (for example, position sensors  16   f  and  16   r  in  FIG. 4 ), which are described later. 
     Hereinafter, for the convenience of description, the longitudinal direction of the display unit  10   f  (that is, the display unit  10   f  illustrated in  FIG. 1A  described below) in an unrolled state described later is referred to as a Z direction. In the first embodiment, the negative Z direction is referred to as a downward direction. Similarly, the positive Z direction is referred to as an upward direction. The Z direction may be referred to as a height direction (up-and-down direction). The Z direction may be the vertical direction or the horizontal direction (the direction perpendicular to the vertical direction). 
     Similarly, the lateral direction of the display unit  10  in the unrolled state is referred to as a Y direction. The Y direction may be referred to as a width direction. Similarly, the direction orthogonal to the Y direction and Z direction is referred to as an X direction. The X direction may be referred to as a depth direction. 
     The display unit  10   f  (first display unit) is a deformable display unit having flexibility. The display unit  10   f  may be a known EL display (for example, organic EL display). More specifically, the display unit  10   f  is formed in a sheet shape (film shape) to be rollable. 
     A side (side in the negative direction of X-axis in  FIGS. 1A and 1B ) where an active area (displayable area) of the display unit  10   f  is provided is referred to as the front side of the display unit  10   f . Similarly, a side opposite to the front side of the display unit  10   f  is referred to as the back side of the display unit  10   f . The display unit  10   f  displays (shows) images to a user (viewer) facing the front side of the display unit  10   f.    
     In the display unit  10   r  (second display unit), an active area is provided on a side opposite to the display unit  10   f . A side (side in the positive direction of X-axis in  FIGS. 1A and 1B ) where the active area of the display unit  10   r  is provided is referred to as the front side of the display unit  10   r . Similarly, a side opposite to the front side of the display unit  10   r  is referred to as the back side of the display unit  10   r . The display unit  10   r  displays images to the user facing the front side of the display unit  10   r.    
     As illustrated in  FIGS. 1A and 1B , when the display unit  10   f  and the display unit  10   r  are provided, the front side of the display unit  10   r  is positioned on the back side of the display unit  10   f . Similarly, the back side of the display unit  10   r  is positioned on the front side of the display unit  10   f . Thus, the display device  1  can display images on the side in the negative direction and on the side in the positive direction of the X-axis of  FIGS. 1A and 1B . The display device  1 , for example, may be used as a double-sided signage. 
     The rolling mechanism  110   f  is a mechanism to roll up (take up) the display unit  10   f . The rolling mechanism  110   f  rolls up the display unit  10   f  by reducing a length H in the height direction of the link member  111   f . Further, at least part of the rolled area described later is drawn out (sent out) from the rolling mechanism  110   f  to the outside of the rolling mechanism  110   f  by increasing the length H. The rolling mechanism  110   f  includes a driving unit (for example, a motor), not illustrated, to drive the link member  111   f . The structure of the link member  111   f  is known, and thus its description is omitted. 
     In the first embodiment, for the convenience of description, a case where the display unit  10   f  (unrolled area) is drawn out in the downward direction (for example, the vertical direction) of the rolling mechanism  110   f  is exemplified. However, the direction in which the display unit  10   f  is drawn out by the rolling mechanism is not particularly limited to the downward direction. The aforementioned direction, for example, may be a direction opposite to the vertical direction, or may be a direction (horizontal direction) orthogonal to the vertical direction. 
       FIG. 1A  is a perspective view illustrating a state (unrolled state) where the display unit  10   f  is not rolled. Herein, the equilibrium length in the Z direction of the display unit  10   f  is referred to as a length L 0  (maximum length). Further, a length in the height direction from the rolling mechanism  110   f  (more specifically, the lower end of the rolling mechanism  110   f ) to the lower end of the display unit  10   f  is referred to as a length La (exposure length). In the unrolled state, La is equal to L 0 . 
     The rolling mechanism  110   f  operates the link member  111   f  and equates the length H with the length L 0 , thereby rolling down the display unit  10   f  to its maximum. That is, the rolling mechanism  110   f  increases the length La to the length L 0  and puts the display unit  10   f  in the unrolled state. 
     Hereinafter, an unrolled part (part with the length La, hanging in the downward direction of the rolling mechanism  110   f ) of the display unit  10   f  is referred to as an unrolled area. In the unrolled state, the whole of the display unit  10   f  is the unrolled area. In the unrolled state, the whole of the display unit  10   f  is provided for a user as an area (visually recognizable area) on which the user can visually recognize images. 
       FIG. 1B  is a perspective view illustrating a state (partially rolled state) where part of the display unit  10   f  is rolled. The rolling mechanism  110   f  operates the link member  111   f  to reduce the length La, such that the length La is less than the length L 0 . That is, the rolling mechanism  110   f  rolls up the display unit  10   f  and puts the rolled up display unit  10   f  in a rolled state. 
     In the partially rolled state, a rolled part of the display unit  10   f  is referred to as a rolled area. In the partially rolled state, the rolled area of the display unit  10   f  is stored in the interior of the rolling mechanism  110   f . When the length of the rolled area of the display unit  10   f  is represented as Lb (non-exposure length, storage length), Lb=L 0 −La. In the partially rolled state, 0&lt;Lb&lt;L 0  holds true. Note that in the aforementioned unrolled state, Lb=0. 
     In the partially rolled state, the rolled area of the display unit  10   f  is an area (visually unrecognizable area) on which the user cannot visually recognize images. That is, the unrolled area, which is an area excluding the rolled area from the whole of the display unit  10   f , is provided for the user as a visually recognizable area. As described later, the display device  1  displays images only on the unrolled area of the display unit  10   f  in the partially rolled state. 
     The protecting member  120   f  is a plate-shaped member formed of a transparent material such as glass or resin. The protecting member  120   f  is provided to protect the display unit  10   f  without impairing the viewability of a user who views images displayed on the display unit  10   f . For example, the provision of the protecting member  120   f  can prevent the user from touching the display unit  10   f.    
       FIG. 2  is a view schematically illustrating the configuration of the display unit  10 . In  FIG. 2 , for the convenience of description, only the display unit  10   f  in the unrolled state is illustrated. Further, in  FIG. 2 , the illustration of the link member  111   f  and the protecting member  120   f  is omitted. As illustrated in  FIG. 2 , the display unit  10   f  includes an edge portion  11   f  (lowermost edge portion) at the lower end thereof. The edge portion  11   f  is an end portion in the unrolled area that is positioned on the opposite side of the rolling mechanism  110   f.    
     As illustrated in  FIG. 5B  described later, a terminal  12   f  is provided at the edge portion  11   f  of the display unit  10   f . Similarly, as illustrated in  FIG. 5B , an edge portion  11   r  (lowermost edge portion) similar to the edge portion  11   f  is provided in the display unit  10   r . Further, a terminal  12   r  similar to the terminal  12   f  is provided at a U-shaped end portion of the edge portion  11   r . The edge portions  11   f  and  11   r  may be collectively referred to as an edge portion  11  (lowermost edge portion) and the terminals  12   f  and  12   r  may be collectively referred to as a terminal  12 . The terminal  12  provided at the edge portion  11  may be used in the display device  1  as a terminal to receive a signal inputted from outside. 
       FIGS. 3A to 3C  are each views for describing the edge portion  11  (lowermost edge portion). As illustrated in  FIG. 3A , the edge portion  11  includes a primary end portion  1111   h  and side end portions  1111   s.    
     The primary end portion  1111   f  is a portion parallel to the Y direction (second direction, row direction described later) in the edge portion  11 . The side end portions  1111   s  are portions parallel to the Z direction (first direction, column direction described later) in the edge portion  11 . In the display unit  10 , two side end portions  1111   s  connecting to the primary end portion  1111   h  are provided on both sides of one primary end portion  1111   h.    
     As illustrated in  FIG. 3B , the edge portion  11  may be electrically connected to a wire LN extending in the Z direction with the primary end portion  1111   h . The terminal  12  can be electrically connected to the wire LN extending in the Z direction by providing the primary end portion  1111   h.    
     Similarly, as illustrated in  FIG. 3C , the edge portion  11  may be electrically connected to the wire LN extending in the Y direction with the side end portion  1111   s . The terminal  12  can be electrically connected to the wire LN extending in the Y direction by providing the side end portion  1111   s.    
       FIG. 5A  is a view schematically illustrating the configuration of the display device  1  in  FIGS. 1A and 1B  when viewed from the side surface.  FIG. 5B  is an enlarged view of an area DD 1  (area including the vicinity of the lower ends of the display units  10   f  and  10   r ) of  FIG. 5A . As illustrated in  FIG. 5B , the terminal  12   f  is provided at the edge portion  11   f . Specifically, the edge portion  11   f  includes a substantially U-shaped end portion (hereinafter, U-shaped end portion) that curves from the front side to the back side and from the lower side to the upper side of the display unit  10   f . The terminal  12   f  is provided at the aforementioned end portion of the edge portion  11   f.    
     The terminal  12   f  is provided as described above, which prevents the terminal  12   f  from being visually recognized by a user (user who views images displayed on the display unit  10   f ) positioned in front of the display device  1 . Thus, even when the terminal  12   f  is provided, display quality of the display unit  10   f  can be maintained. A wire portion  10   f   1  to connect the terminal  12   f  with other members (in particular, a first voltage primary wiring line  191 H described later and the like) is provided in the interior of the edge portion  11   f.    
     As illustrated above, an edge portion  11   r  similar to the edge portion  11   f  is provided at the lower end of the display unit  10   r . Further, the terminal  12   r  similar to the terminal  12   f  is provided at the U-shaped end portion of the edge portion  11   r . A wire portion  10   r   1  similar to the wire portion  10   f   1  is provided in the interior of the edge portion  11   r.    
     Configuration of Main Components of Display Device  1   
       FIG. 4  is a functional block diagram illustrating a configuration of main components of the display device  1 . The display device  1  further includes a control unit  15 , position sensors  16   f  and  16   r , a power source circuit  19 , and a storing unit  90 . The position sensors  16   f  and  16   r  may be collectively referred to as position sensors  16 . 
     The position sensors  16  are sensors for detecting the unrolled area of the display unit  10 . For example, the position sensors  16  may be electrostatic capacitance type sensors (e.g., touch sensors) or may be optical sensors. When the optical sensor is used as the position sensor  16 , a light emitting element  170  described later (electro-optic element) may be used as the light receiving element of the optical sensor. 
     As illustrated in  FIG. 9  described later or the like, a plurality of position sensors  16  is regularly arranged along the Z direction (first direction, row direction) in the display unit  10 . However, the position sensors  16  may be provided outside the display unit  10 . 
     A power source circuit  19  supplies electric power to respective units of the display device  1 . As described below, the power source circuit  19  supplies a voltage to each of a plurality of pixel circuits  17  described later. 
     A control unit  15  controls respective units of the display device  1  in an integrated manner. The functions of the control unit  15  may be achieved by a Central Processing Unit (CPU) executing programs stored in a storing unit  90 . The storing unit  90  stores various programs to be executed by the control unit  15  and data used by a program. 
     The control unit  15  includes a display control unit  151  and a rolling control unit  152 . The rolling control unit  152  controls the operation of the rolling mechanism  110 . The rolling control unit  152 , for example, may operate the driving unit of the rolling mechanism  110  in accordance with the input operation of a user to change the aforementioned length H (in other words, the length Lb). This allows the aforementioned length La to be changed to any length as desired by the user. That is, the size of the unrolled area (visually recognizable area) can be changed to any size. 
     Note that, it is preferable that the input operation of the user on the display device  1  is performed with wireless communications using a remote control or the like. In this case, it is not required to provide an input unit in the display device  1 , and thus the designability of the display device  1  can be improved. However, an input unit may be provided in the display device  1 . 
     The display control unit  151  controls the operation of the display unit  10 . The display control unit  151  may cause the display unit  10  to display images only on the unrolled area of the display unit  10  on the basis of the detection results of the position sensors  16 . An example of the display control of the display unit  10  by the display control unit  151  is described later. 
       FIG. 6  is a view illustrating one example of the pixel circuit  17  of the display unit  10 . The pixel circuit  17  is a pixel circuit corresponding to one pixel of the display unit  10 . A plurality of pixel circuits  17 , whose number corresponds to the number of pixels of the display unit  10 , is aligned in a spatially regular order in the display unit  10 . 
     Note that other members except for the light emitting element  170 , a high-level voltage terminal (terminal of electric potential VDD), and a low-level voltage terminal (terminal of electric potential VSS), which are described later, are illustrated, but the descriptions of the other members are appropriately omitted. 
     The pixel circuit  17  includes the light emitting element  170 . The light emitting element  170  is a light source to illuminate a pixel corresponding to the pixel circuit  17 . The light emitting element  170  is an electro-optic element in which luminance or transmissivity is controlled by a current. An example of a current-control-type electro-optic element includes Organic Light Emitting Diode (OLED), an inorganic light emitting diode, or Quantum dot Light Emitting Diode (QLED). 
     For example, the OLED includes a first electrode (e.g., positive electrode), a second electrode (e.g., negative electrode) formed on the first electrode, and a light emitting layer between the first electrode and the second electrode). A voltage that is equal to or higher than a threshold value of the light emitting layer is applied between the first electrode and the second electrode to pass a drive current (active current) through the light emitting layer, thereby causing the light emitting layer to emit light. 
     Accordingly, the display device is not particularly limited as long as the display unit  10  has flexibility and includes a bendable light emitting element  170  (electro-optic element). The display unit  10  may be an organic Electro Luminescence (EL) display including the OLED or may be an inorganic EL display including the inorganic light emitting diode. As described above, the display unit  10  may be a known EL display. Alternatively, the display unit  10  may be a QLED display including a QLED. 
     In  FIG. 6 , Di denotes an i-th (i: an integer) data signal wiring line in the display unit  10  (see  FIG. 9  described later). Sj and Sj+1 are j-th (j: an integer) and j+1-th scanning wiring lines of the display unit  10 . Further, Ej is a j-th light emission control wiring line of the display unit  10 . The light emission control wiring line Ej is provided corresponding one-to-one to a scanning wiring line Sj (see  FIG. 9 ). 
     T 1  to T 6  in  FIG. 6  denote Thin Film Transistors (TFTs). The T 1  to T 6  may be used as switching elements. As illustrated in  FIG. 6 , the gates of T 3  and T 4  are connected to the light emission control wiring line Ej. Similarly, the gates of T 2  and T 5  are connected to the scanning wiring line Sj+1. Similarly, the gate of T 6  is connected to the scanning wiring line Sj. 
     When a scanning signal is inputted to the scanning wiring line Sj, the scanning signal is applied to the gate of T 6 , thereby bringing T 6  into an ON (conduction) state. Similarly, when a scanning signal is inputted to the scanning wiring line Sj+1, the scanning signal is applied to the gates of T 2  and T 5 , thereby bringing T 2  and T 5  into an ON state. When a control signal is inputted to the light emission control wiring line Ej, the scanning signal is applied to the gate of T 4 , thereby bringing T 4  into an ON state. 
     A data signal (analog voltage signal) corresponding to an image displayed on the display unit  10  is inputted to a data signal wiring line Di. The data signal from the data signal wiring line Di is inputted to the pixel circuit  17  via T 2 . 
     The anode of the light emitting element  170  is electrically connected to the high-level voltage terminal via T 3 , T 1 , and T 4 . Similarly, the cathode of the light emitting element  170  is electrically connected to the low-level voltage terminal. When a voltage (potential difference) between the anode and the cathode of the light emitting element  170  is represented as VP, VP=VDD−VSS. 
     The high-level voltage terminal is connected to a first voltage primary wiring line  191 H described later via the terminal  12 . A voltage VDD is applied from the power source circuit  19  to the first voltage primary wiring line  191 H as a first voltage. The voltage VDD may be constant voltage, for example, from 5 V to 10 V. 
     The low-level voltage terminal is electrically connected to the second electrode (negative electrode) of the pixel circuit  17 . The negative electrode may be an integrated electrode (so called solid electrode) that is commonly used for the plurality of pixel circuits  17  (at least two pixel circuits  17 ). As illustrated in  FIG. 7  described later, an electrode  900  may be formed as the solid electrode to cover all the light emitting elements  170 . 
     As illustrated in  FIG. 7 , the electrode  900  may be connected to a second voltage primary wiring line  192 L described later in the edge portion  11 . A voltage VSS is applied from the power source circuit  19  to the second voltage primary wiring line  192 L as a second voltage. The second voltage is set to a voltage lower than the first voltage. The voltage VSS may be constant voltage, for example, from −5V to 5V. 
     When a scanning signal is inputted to the scanning wiring lines Sj and Sj+1, a control signal is inputted to the light emission control wiring line Ej, and a data signal is inputted to the data signal wiring line Di (hereinafter, illumination condition), the TFTs T 1  to T 6  are put into an ON state. That is, the voltage VDD can be supplied from the high-level voltage terminal to the anode of the light emitting element  170 . Thus, a drive current to cause (drive) the light emitting element  170  to emit light can be supplied from the high-level voltage terminal to the light emitting element  170 . 
     In contrast, when the aforementioned illumination condition is not satisfied, the supply of the voltage VDD from the high-level voltage terminal to the anode of the light emitting element  170  can be stopped. Thus, the drive current does not flow. As described above, according to the pixel circuits  17 , the drive (generation or no generation of the drive current) of the light emitting element  170  can be selectively switched. 
     Configuration to Supply Voltage from Power Source Circuit to Pixel Circuit 
       FIG. 7  is a view for describing the configuration to supply voltage (first voltage, second voltage) from the power source circuit  19  to each of the plurality of pixel circuits  17 . In  FIG. 7 , for the convenience of description, the unrolled area of the display unit  10  is illustrated in an expanded state. In this respect, the same is applied to  FIG. 9  described later. 
     The display device  1  includes (i) the first voltage primary wiring line  191 H that supplies the first voltage from the power source circuit  19  to the respective pixel circuits  17 , and (ii) the second voltage primary wiring line  192 L that supplies the second voltage from the power source circuit  19  to the respective pixel circuits  17 . 
     As illustrated in  FIG. 7 , the aforementioned electrode  900  (negative electrode, second electrode) is electrically connected to the second voltage primary wiring line  192 L at the lowermost edge portion (the aforementioned edge portion  11 ) of the rolled area. More specifically, the second voltage primary wiring line  192 L is electrically connected to a connection portion  910  which is a wire of a TFT layer electrically connected with the electrode  900 . 
       FIG. 8  is a cross-sectional view schematically illustrating the configuration of electrically connecting the electrode  900  and the second voltage primary wiring line  192 L. As illustrated in  FIG. 8 , the electrode  900  is electrically connected to the second voltage primary wiring line  192 L via a wire (for example, the connection portion  910 ) formed on the TFT layer. Note that the TFT layer, for example, is a layer on which the aforementioned TFTs T 1  to T 6  are provided, out of the layers of the display unit  10 . Besides the TFTs T 1  to T 6 , more TFTs (switching element) may be provided on the TFT layer. 
       FIG. 7  or the like is illustrated as if the connection portion  910  was not provided at the end portion of the display unit  10  on the side of the rolling mechanism  110 . However, the connection portion  910  may be formed on part or whole of the end portion along the end portion of the display unit  10  on the side of the rolling mechanism  110 . 
     The second voltage primary wiring line  192 L may be electrically connected to the connection portion  910  via the side end portion  1111   s  of the edge portion  11  (see also  FIG. 3C ). However, as illustrated in  FIG. 9  described later or the like, the second voltage primary wiring line  192 L may be electrically connected to the connection portion  910  via the primary end portion huh of the edge portion  11  (see also  FIG. 3B ). 
     The display device  1  includes a plurality of first voltage wiring lines H 1  to Hm extending from the first voltage primary wiring line  191 H to the respective plurality of pixel circuits  17 . The first voltage wiring lines H 1  to Hm are provided corresponding one-to-one to data signal wiring lines D 1  to Dm illustrated in  FIG. 7  described later. 
     In  FIG. 7 , the first voltage wiring line H 1  and the data signal wiring line D 1  are respectively a first voltage wiring line and a data signal wiring line positioned at the left end of the display unit  10 . Similarly, the first voltage wiring line Hm and the data signal wiring line Dm are respectively a first voltage wiring line and a data signal wiring line positioned at the right end of the display unit  10 . The first voltage wiring line and the data signal wiring line are numbered such that the number is increased one by one from the left side to the right side of the sheet of  FIG. 7  (in the positive Y direction). 
     Similar to the data signal wiring lines D 1  to Dm, the first voltage wiring lines H 1  to Hm extend in the Z direction (first direction, a direction parallel to the direction in which the display unit  10  is drawn out from the rolling mechanism  110 ) and are provided parallel to each other along the Y direction (second direction, a direction intersecting with the first direction). 
     In the first embodiment, the column direction of the display unit  10  is the Z direction, and the row direction of the display unit  10  is the Y direction. The first voltage primary wiring line  191 H supplies the first voltage to the respective pixel circuits  17  via the plurality of first voltage wiring lines H 1  to Hm. Note that in the display unit  10 , the respective pixel circuits  17  are regularly arranged in a matrix form along the Z direction and the Y direction. It is to be understood that the aforementioned letter m represents the number of pixels in the horizontal direction of the display unit  10 . Similarly, it is to be understood that a letter n described below represents the number of pixels in the vertical direction of the display unit  10 . 
     As illustrated in  FIG. 7 , the respective pixel circuits  17  positioned on the same column (e.g., the first column) are connected in series to one first voltage wiring line (e.g., the first voltage wiring line H 1 ) corresponding to the column. Thus, for example, the pixel circuit  17  (the pixel circuit  17  positioned in the first row) positioned at the lowermost edge portion, out of the plurality of pixel circuits  17  positioned in the first column, is electrically connected to the first voltage wiring line H 1  first. 
     Herein, “the pixel circuit  17  positioned at the lowermost edge portion is electrically connected to the first voltage wiring line H 1  first” means that the pixel circuit  17  positioned at the end portion (strictly speaking, the pixel circuit  17  contributed to the light emission of the display unit  10 ) is connected to the first voltage wiring line H 1  without connecting with other pixel circuits  17  (pixel circuits positioned in the second row onward). 
     However, when a predetermined threshold-value length Lth is determined with respect to the displayable area (active area) of the display unit  10 , “the pixel circuit  17  positioned at the lowermost edge portion is electrically connected to the first voltage wiring line H 1  first” means that the pixel circuit  17  positioned in a range of the threshold-value length Lth from the lowermost edge portion is electrically connected to the first voltage wiring line H 1 . Hereinafter, the same is applied to words “electrically connected first” used in other descriptions. 
     Note that the threshold-value length Lth is a threshold value of the aforementioned length La (exposure length). When the display unit  10  is drawn out from the rolling mechanism  110  by less than threshold-value length Lth, the display control unit  151  may carry out control such as not to illuminate the unrolled area of the display unit  10  even in the case where the display unit  10  is drawn out from the rolling mechanism  110 . In the case where the threshold-value length Lth is determined, when the display unit  10  is drawn out from the rolling mechanism  110  by the threshold-value length Lth or longer, the display control unit  151  may carry out control to illuminate the unrolled area of the display unit  10 . 
     As described above, in the display device  1 , the first voltage primary wiring line  191 H is electrically connected to the pixel circuits  17  positioned at the lowermost edge portion first, out of the plurality of pixel circuits  17  (via the first voltage wiring lines H 1  to Hm). Note that a group of pixel circuits  17  positioned at the lowermost edge portion is illustrated as PIX 1  in  FIG. 9  described below. 
     Alternatively, in the display device in accordance with an aspect of the disclosure, the second voltage primary wiring line  192 L may be provided electrically connected with the pixel circuits  17  positioned at the lowermost edge portion first, out of the plurality of pixel circuits  17 . That is, the display device in accordance with an aspect of the disclosure may be configured such that at least one of the first voltage primary wiring line  191 H and the second voltage primary wiring line  192 L is electrically connected with the pixel circuits  17  positioned at the lowermost edge portion first, out of the plurality of pixel circuits  17 . 
     Note that the display unit  10  may include pixel circuits (dummy pixel circuits) in which the light emitting element is not provided, besides the pixel circuits  17  (hereinafter, light emitting pixel circuits) including the pixel circuit  170 . In this case, at least one of the first voltage primary wiring line  191 H and the second voltage primary wiring line  192 L may be electrically connected to the light emitting pixel circuit nearest to the lowermost edge portion first, out of the plurality of light emitting pixel circuits. Note that, in the explanation of the present Description, “electrically connected” is also simply referred to as “connected”. 
     Configuration to Control Supply of Voltage from Power Source Circuit to Pixel Circuit 
       FIG. 9  is a view for describing control of voltage supply from the power source circuit  19  to the power source circuits  17 . As illustrated in  FIG. 9 , the display device  1  includes a data signal wiring line drive circuit  195  for driving the data signal wiring lines D 1  to Dm (supplying the data signals to the data signal wiring lines D 1  to Dm), a scanning wiring line drive circuit  196  for driving the scanning wiring lines S 1  to Sn (supplying the scanning signals to the scanning wiring lines S 1  to Sn), and a light emission control wiring line drive circuit  197  for driving the light emission control wiring lines E 1  to En (supplying the control signals to the light emission control wiring lines E 1  to En). Each of the data signal wiring line drive circuit  195 , the scanning wiring line drive circuit  196 , and the light emission control wiring line drive circuit  197  is controlled by the display control unit  151 . 
     In  FIG. 9 , the scanning wiring line S 1  and the light emission control wiring line E 1  are the scanning wiring line and the light emission control wiring line positioned at the lower end of the display unit  10 , respectively. Similarly, the scanning wiring line Sn and the light emission control wiring line En are the scanning wiring line and the light emission control wiring line positioned at the upper end of the display unit  10 , respectively. The scanning wiring lines and the light emission control wiring lines are numbered such that the number is increased one by one from the lower side to the upper side of the sheet of  FIG. 9  (in the positive Z direction). In this way, the light emission control wiring lines E 1  to En are provided corresponding one-to-one to the scanning wiring lines S 1  to Sn. 
     As illustrated in  FIG. 9 , the scanning wiring lines S 1  to Sj and the light emission control wiring lines E 1  to Ej correspond to the respective pixel circuits  17  included in the rolled area. Similarly, the scanning wiring lines Sj+1 to Sn and the light emission control wiring lines Ej+1 to En correspond to the respective pixel circuits  17  included in the unrolled area. 
     As described above, the plurality of position sensors  16  are regularly arranged along the Z direction in the display unit  10 . Each of the rolled area and the unrolled area can be detected on the basis of the detection results of the position sensors  16 . For example, the display control unit  151  may obtain the detection results of the position sensors  16  and carry out the aforementioned detection (determination). 
     For example, in the case where the position sensors  16  are optical sensors, when one position sensor  16  detects light which has an intensity equal to or higher than a predetermined value, it may be determined that a position at which the position sensor  16  is provided is in the unrolled area. In contrast, when one position sensor  16  detects light which has an intensity less than a predetermined value, it may be determined that a position at which the position sensor  16  is provided is in the rolled area. 
     The scanning wiring lines S 1  to Sn and the light emission control wiring lines E 1  to Ej intersect with the data signal wiring lines D 1  to Dm. The scanning wiring lines S 1  to Sn and the light emission control wiring lines E 1  to Ej extend to the plurality of pixel circuits  17  in the Y direction (second direction) and are aligned along the Z direction (first direction). 
     The display control unit  151  may control to cause the display unit  10  to display images only on the unrolled area and prevent the display unit  10  from displaying the images on the rolled area. More specifically, the display control unit  151  may control the data signal wiring line drive circuit  195  and the scanning wiring line drive circuit  196  to cause only the light emitting elements  170  provided in the pixel circuits  17  included in the unrolled area to emit light (pass the drive current through only the light emitting elements  170 ). 
     This control can prevent the light emitting elements  170  provided in the pixel circuits  17  included in the rolled area from emitting light (prevent the drive current from passing through the light emitting elements  170 ). For example, the display control unit  151  may perform the control of at least any of (1) to (3) described below. 
     (1) The display control unit  151  may control the scanning wiring line drive circuit  196  and input the scanning signals only to the scanning wiring lines S 1  to Sj corresponding to the pixel circuits  17  included in the unrolled area, out of the scanning wiring lines S 1  to Sn. This prevents the scanning signals from being inputted to the scanning wiring lines Sj+1 to Sn corresponding to the pixel circuits  17  included in the rolled area, out of the scanning wiring lines S 1  to Sn. Thus, images can be displayed only on the unrolled area. 
     (2) The display control unit  151  may control the light emission control wiring line drive circuit  197  and input the control signals only to the light emission control wiring lines E 1  to Ej corresponding to the pixel circuits  17  included in the unrolled area, out of the light emission control wiring lines E 1  to En. This prevents the control signals from being inputted to the light emission control wiring lines Ej+1 to En corresponding to the pixel circuits  17  included in the rolled area, out of the light emission control wiring lines E 1  to En. Thus, images can be displayed only on the unrolled area. 
     (3) The display control unit  151  may control the data signal wiring line drive circuit  195  and input the data signals only to the pixel circuits  17  included in the unrolled area. This prevents the data signals from being inputted to the pixel circuits  17  included in the rolled area. Thus, images can be displayed only on the unrolled area. 
     As described above, the display control unit  151  can determine target pixel circuits  17  to which the signals are inputted, out of the plurality of pixel circuits  17  on the basis of the detection results of the position sensors  16 . Note that “the signals” herein may include any signal. For example, the signals include the data signal, the scanning signal, and the control signal. 
     Note that the magnitude of a voltage (the intensity of a signal) applied to the scanning wiring lines S 1  to Sn and the light emission control wiring lines E 1  to En is typically larger than the magnitude of a voltage applied to the data signal wiring lines D 1  to Dm. As one example, the magnitude of a voltage applied to the scanning wiring lines S 1  to Sn and the light emission control wiring lines E 1  to En is from 10 V to 20 V. Similarly, the magnitude of a voltage applied to the data signal wiring lines D 1  to Dm is from 2 V to 5 V. 
     Further, parasitic capacitance and resistance that are unintended in the process of designing are present in the wire of the display unit  10 , and when the aforementioned voltage is applied, a minute current (passive current) flows due to the voltage. Then, this minute current may generate heat in the display unit  10 . 
     Thus, it is preferable that the scanning wiring lines S 1  to Sn and the light emission control wiring lines E 1  to En (the signal lines to which a high voltage is applied) are provided extending in the Y direction (second direction, row direction) to efficiently prevent generation of heat in the unrolled area of the display unit  10 . Similarly, it is preferable that the data signal wiring lines D 1  to Dm are provided extending in the Z direction (first direction, column direction). 
     One Example of Display Control with Display Control Unit  151   
       FIGS. 10A and 10B  are views illustrating one example of display control of the display control unit  151 . The display control unit  151  may set a section (hereinafter, a display section Ar) for displaying an image IMG 1  on the unrolled area on the basis of the length of the unrolled area and an aspect ratio of the image IMG 1  to be displayed on the display unit  10 . Note that sections on which the image IMG 1  is not displayed in the unrolled area are referred to as non-display sections An. 
     As one example, it is assumed that the aspect ratio of the image IMG 1  is represented as lateral length:longitudinal length=16:9. That is, when a length in the lateral direction of the image IMG 1  is represented as w 1  and a length in the longitudinal direction of the image IMG 1  is represented as t 1 , w 1 :t 1 =16:9. However, the aspect ratio of the image IMG 1  may be set to any ratio. Note that the longitudinal direction (vertical direction) and the lateral direction (horizontal direction) of the image IMG 1  are set in advance. 
     Herein, a length in the lateral direction of the display unit  10  is represented as W 1 . As illustrated in  FIG. 10A , when the length La of the unrolled area is relatively short, the display control unit  151  may set the display section Ar to the entire unrolled area in the up-and-down direction. That is, the display control unit  151  may reduce the size of the image IMG 1  to display the image IMG 1  while maintaining the aspect ratio of the image IMG 1 . In this case, the length w 1  in the lateral direction of the image IMG 1  is set to be shorter than a length W. 
       FIG. 10A  exemplifies a case where the display section Ar is set in the center in the lateral direction of the unrolled area, and the non-display sections An are set on both ends in the lateral direction of the unrolled area (sections excluding the display section Ar in the unrolled area). However, the display section Ar may be set to any position. For example, in  FIG. 10A , the display section Ar may be set to be abutting to the left end or the right end of the unrolled area. 
     Further, as illustrated in  FIG. 10B , when the length La of the unrolled area is relatively long, the display control unit  151  may set the length w 1  in the lateral direction of the image IMG 1  to be equal to the length W while maintaining the aspect ratio of the image IMG 1 . In this case, the length t 1  in the longitudinal direction of the image IMG 1  may be set to be shorter than the length La of the unrolled area. 
       FIG. 10B  exemplifies a case where the display section Ar is set in the center in the longitudinal direction of the unrolled area, and the non-display sections An are set on both ends in the longitudinal direction of the unrolled area (sections excluding the display section Ar in the unrolled area). However, as described above, the display section Ar may be set abutting to the upper end or the lower end of the unrolled area. 
     As described above, the display of the image IMG 1  can be changed in accordance with the length of the unrolled area by setting the display section Ar while maintaining the aspect ratio of the image IMG 1 , so that display quality for the user can be enhanced. 
     Effects of Display Device  1   
     In accordance with the display device  1 , images can be displayed only on the unrolled area of the display unit  10 . More specifically, only the light emitting elements  170  provided in the pixel circuits  17  included in the unrolled area can emit light (the drive current can be passed through the light emitting elements  170 ). 
     That is, the light emitting elements  170  provided in the pixel circuits  17  included in the rolled area (an area having a small heat dissipation area, compared with the unrolled area) can be prevented from emitting light (the drive current is prevented from passing through the light emitting elements  170 ). 
     In particular, in the display device  1 , the terminal  12  is provided at the edge portion  11  of the display unit  10 . Accordingly, the first voltage primary wiring line  191 H is connected to the pixel circuits  17  arranged at the edge portion  11  first. Thus, the aforementioned drive current first flows into the pixel circuits  17  arranged at the edge portion  11  via the first voltage primary wiring line  191 H. 
     Consequently, when images are displayed only on the unrolled area of the display unit  10 , the drive current can be passed through only the pixel circuits  17  included in the unrolled area without passing through the pixel circuits  17  included in the rolled area. 
     As a result, a Joule&#39;s heat attributed to the drive current can be prevented from generating in the rolled area. Consequently, an increase in the temperature of the rolled area can be prevented, and the deterioration of the display device  1  due to the increase in the temperature of the rolled area can be prevented. 
     Modification 
     Hereinafter, a display device  1   u  will be described with reference to  FIG. 11  as one modification of the display device  1 . As illustrated in  FIG. 11 , the display device  1   u  includes a pixel circuit  17   u . The pixel circuit  17   u  is one modification of the aforementioned pixel circuit  17 . 
     The pixel circuit  17   u  includes a light emitting element  170   r  for emitting red (Red) light, a light emitting element  170   g  for emitting green (Green) light, and a light emitting element  170   b  for emitting blue (Blue) light. The light emitting elements  170   r ,  170   g , and  170   b  are electro-optic elements similar to the light emitting elements  170  described above. 
     The anodes of the light emitting elements  170   r ,  170   g , and  170   b  are connected to a common high-level voltage terminal (electric potential: VDD). The common high-level voltage terminal, for example, may be connected to the aforementioned electrode  900  (solid electrode). 
     On the other hand, respective cathodes of the light emitting elements  170   r ,  170   g , and  170   b  are connected to individual high-level voltage terminals. Specifically, the cathode of the light emitting element  170   r  is connected to a first low-level voltage terminal (electric potential; Vssr) via a TFT T 2   r , and the cathode of the light emitting element  170   g  is connected to a second low-level voltage terminal (electric potential: Vssg) via a TFT T 2   g , and the cathode of the light emitting element  170   b  is connected to a third low-level voltage terminal (electric potential: Vssb) via a TFT T 2   b . The voltages Vssr, Vssg, and Vssb correspond to the aforementioned second voltage. 
     As described above, in the display device in accordance with an aspect of the disclosure, at least one of the first voltage primary wiring line  191 H and the second voltage primary wiring line  192 L is electrically connected with the pixel circuits  17  arranged at the lowermost edge portion first, out of the plurality of pixel circuits  17 . Thus, the display device  1   u  including the pixel circuits  17   u  has the same effects as those of the display device  1 . 
     Modification 
     Hereinafter, a display device  1   v  will be described with reference to  FIGS. 12A and 12B  as another modification of the display device  1 .  FIG. 12A  is a schematic side view of the display device  1   v .  FIG. 12B  is an enlarged view of an area DD 2  (area including the vicinity of the lower ends of the display units  10   f  and  10   r ) of  FIG. 12A . 
     Note that the edge portions of the display device  1   v  are referred to as edge portions  11   fv  and  11   rv , and the wire portions of the display device  1   v  are referred to as wire portions  10   flv  and  10   rlv  to be distinguished from the edge portions  11   f  and  11   r  and the wire portions  10   f   1  and  10   r   1  of the display device  1 . 
     As illustrated in  FIGS. 12A and 12B , U-shaped end portions are formed in the edge portions  11   fv  and  11   rv  substantially along an arc. That is, the edge portions  11   fv  and  11   rv  are configured such that the curvature of the edge portions  11   fv  and  11   rv  (in particular, the U-shaped end portions) smoothly (consecutively) changes. Stress can be prevented from concentrating on parts (in particular, parts of the U-shaped end portions) of the edge portions  11   fv  and  11   rv  by smoothly changing the curvature of the edge portions  11   fv  and  11   rv . Consequently, damage of the terminal  12  and the wires in the vicinity of the terminal  12  can be prevented. As a result, the reliability of the display device  1   v  can be improved. 
     Second Embodiment 
     A description follows regarding the second embodiment of the disclosure with reference to  FIGS. 13A and 13B . Note that, for the convenience of description, members having the same function as the components stated in the aforementioned embodiment are appended with the same reference signs, and the description thereof is omitted. 
       FIG. 13A  is a view schematically illustrating the configuration of a display device  2  of the second embodiment. The display device  2  includes only one display unit  20 , in place of the two display units  10   f  and  10   r . That is, the display device  2  is different from the display device  1 , for example, in that the display device  2  is configured as a single-sided signage. The display device  2  is one example of the display device of which the configuration is simplified, compared with the display device  1 . 
     Furthermore, the display device  2  includes a rolling mechanism  210  (rolling mechanism), in place of the rolling mechanism  110  of the display device  1 . The rolling mechanism  210  is a mechanism in which the user manually roll up or roll down the display unit  20 . The configuration of the rolling mechanism  210  is similar to known configuration, and its description is omitted accordingly. In the display device  2 , the rolling control unit  152  of the display device  1  can be omitted. 
       FIG. 13B  is a view schematically illustrating the configuration of the display unit  20  and its vicinity. The rolling mechanism  210  is suspended from a ceiling  92 , for example, with two supporting lines  91 . Note that the edge portion of the display unit  20  is referred to as an edge portion  21 . The edge portion  21  is different from the edge portion  11  in that the edge portion  21  includes a holding part  22 . 
     An opening is formed on the front side of the holding part  22  (the front side of the display unit  20 ). The user can grip the holding part  22 , for example, with two fingers through the opening of the holding part  22 . Then, the user lowers his/her hand downward while gripping the holding part  22 , thereby pulling down (rolling down) the display unit  20 . 
     In the display device  2  also, as is the same with the display device  1 , a current I can be passed through only the unrolled area of the display unit  20  on the basis of the detection results of the position sensors  16 . Consequently, the display device  20  has the same effect as that of the display device  1 . 
     Third Embodiment 
     A description follows regarding a third embodiment of the disclosure with reference to  FIG. 14 .  FIG. 14  is a view illustrating a display device  3  of the third embodiment. The display device  3  has configuration in which the first voltage primary wiring line  191 H of the display device  1  of the first embodiment is replaced with a first voltage primary wiring line  291 H. The first voltage primary wiring line  291 H includes first voltage wiring lines HH 1  to HHn. 
     Similar to the scanning wiring lines S 1  to Sn and the light emission control wiring lines E 1  to En, the first voltage wiring lines HH 1  to HHn extend in the Y direction (row direction, second direction) and are provided parallel to each other along the Z direction (column direction, first direction). The first voltage wiring lines HH 1  to HHn of the first voltage primary wiring line  291 H are provided parallel to and corresponding one-to-one to the scanning wiring lines S 1  to Sn and the light emission control wiring lines E 1  to En. 
     In the display device  3 , the first voltage primary wiring line  291 H is connected to the pixel circuits  17  via the first voltage wiring lines HH 1  to HHn. In this way, the direction in which the first voltage primary wiring line and the first voltage wiring lines are provided is not limited to the direction described in the first embodiment. 
     In the configuration of the display device  3  also, the drive current can be prevented from passing through the pixel circuits  17  included in the rolled area of the display unit  10  by using the drive methods described in (1) to (3) of the aforementioned embodiment. That is, it is possible to allow only the unrolled area of the display unit  10  to illuminate and prevent the rolled area from illuminating. 
     Modification 
       FIG. 15  is a view illustrating a display device  3   v  as the modification of the display device  3  of the third embodiment. In the display device  3   v , switching elements TT 1  to TTn (first switching elements) are provided on the first voltage wiring lines HH 1  to HHn, respectively. In  FIG. 15 , a switching element TTj provided on the j-th first voltage wiring line HHj is illustrated. The switching elements, for example, may be TFTs. 
     In the display device  3   v , when the pixel circuits  17  positioned in the j-th row are included in the unrolled area, the display control unit  151  may bring the switching element TTj into an ON state. Further, when the pixel circuits  17  positioned in the j-th row are included in the rolled area, the display control unit  151  may bring the switching element TTj into an OFF state. This prevents the first voltage from being applied to the pixel circuits  17  included in the rolled area. Thus, the current (passive current) attributed to the aforementioned parasitic capacitance and resistance can be suppressed. This configuration of the display device  3   v  can also prevent generation of heat in the rolled area. 
     As one example, the gate terminal of the switching element TTj may be electrically connected to a light emission control wiring line Ej corresponding to the first voltage wiring line HHj. Then, as described above, a control signal may be inputted only to the light emission control wiring line Ej corresponding to the pixel circuits included in the unrolled area. This configuration can also prevent generation of heat in the rolled area. 
     Fourth Embodiment 
     A description follows regarding a fourth embodiment of the disclosure with reference to  FIG. 16 .  FIG. 16  is a view illustrating a display device  4  of the fourth embodiment. The display device  4  has configuration in which switching elements SS 1  to SSn (second switching elements) are added to the first voltage primary wiring line  291 H in the display device  3  of the third embodiment. The switching elements, for example, may be TFTs. 
     The switching element SSj in the j-th row is interposed between the first voltage primary wiring line  291 H and the first voltage wiring line HHj in the j-th row. That is, the first voltage wiring line HHj in the j-th row is electrically connected to the first voltage primary wiring line  291 H via the switching element SSj. 
     In the display device  4 , when the pixel circuits  17  positioned in the j-th row are included in the unrolled area, the display control unit  151  brings the switching element SSj into an ON state. Similarly, when the pixel circuits  17  positioned in the j-th row are included in the rolled area, the display control unit  151  brings the switching element SSj into an OFF state. Similar to the third embodiment, the aforementioned configuration can also prevent generation of heat in the rolled area. 
     Note that the fourth embodiment exemplifies a case where one switching element is provided for each row. However, in the display device  4 , one switching element may be provided for every plurality of rows (e.g., two rows). 
     Example Implemented by Software 
     A control block (in particular, the control unit  15 ) of the display devices  1  to  4  may be implemented by logic circuits (hardware) fabricated in integrated circuits (IC chips) or may be implemented by software using a Central Processing Unit (CPU). 
     In the case of the latter, the display devices  1  to  4  include the CPU that executes the commands of programs that are softwares for achieving each function, a Read Only Memory (ROM) or a storage device (these are referred to as “storage media”) in which the programs and various data are stored to be readable by a computer (or CPU), a Random Access Memory (RAM) that loads the programs, and the like. Then, a computer (or CPU) reads the programs from the storage media and executes the programs, which achieves an object of the disclosure. As the storage media, “nonvolatile tangible media” such as tapes, disks, cards, semiconductor memories, programmable logic circuits can be employed. Further, the programs may be supplied to the computer via any transmission medium (communication network, broadcast wave, and the like) through which the programs can be transmitted. Note that one aspect of the present disclosure can be achieved in the form of data signals embodied by electronic transmission of the programs and embedded in a carrier wave. 
     Supplement 
     A display device of a first aspect includes: a display unit including a plurality of pixel circuits each including an electro-optic element, the display unit being deformable and having flexibility; a rolling mechanism configured to roll the display unit and store a rolled part of the display unit as a rolled area in an interior of the rolling mechanism; a power source circuit; a first voltage primary wiring line configured to supply a first voltage from the power source circuit to at least one of the plurality of pixel circuits; and a second voltage primary wiring line configured to supply a second voltage lower than the first voltage from the power source circuit to at least one of the plurality of pixel circuits, wherein an area of the display unit excluding the rolled area includes an unrolled area, and an end portion of the unrolled area of the display unit positioned on an opposite side with respect to the rolling mechanism includes a lowermost edge portion, and at least one of the first voltage primary wiring line and the second voltage primary wiring line is electrically connected to at least one pixel circuit arranged at the lowermost edge portion first, out of the plurality of pixel circuits. 
     In a second aspect, the first voltage primary wiring line is electrically connected to at least one pixel circuit arranged at the lowermost edge portion first, out of the plurality of pixel circuits. 
     In a third aspect, the second voltage primary wiring line is electrically connected to at least one pixel circuit arranged at the lowermost edge portion first, out of plurality of the pixel circuits. 
     In a fourth aspect, the display device further includes a plurality of first voltage wiring lines extending from the first voltage primary wiring line to the plurality of pixel circuits in a first direction, wherein the plurality of first voltage wiring lines are provided parallel to each other along a second direction intersecting with the first direction, and the first voltage primary wiring line is electrically connected to at least one pixel circuit arranged at the lowermost edge portion first, out of plurality of the pixel circuits, via the plurality of first voltage wiring lines. 
     In a fifth aspect, the electro-optic element includes a first electrode, a second electrode positioned above the first electrode, and a light emitting layer positioned between the first electrode and the second electrode, the second electrode including an integrated electrode commonly used for at least two of the plurality of pixel circuits, and the second electrode is electrically connected to the second voltage primary wiring line via a wire formed in a Thin Film Transistor (TFT) layer at the lowermost edge portion. 
     In a sixth aspect, the display device further includes: a plurality of data signal wiring lines configured to input an analog voltage signal corresponding to an image to be displayed on the display unit to the pixel circuits; a plurality of scanning wiring lines intersecting with the plurality of data signal wiring lines, and a plurality of light emission control wiring lines intersecting with the plurality of data signal wiring lines and corresponding one-to-one to the plurality of scanning wiring lines, wherein the plurality of data signal wiring lines extend to the plurality of pixel circuits in a first direction and are provided parallel to each other along a second direction intersecting with the first direction, and the plurality of scanning wiring lines and the plurality of light emission control wiring lines extend to the pixel circuits in the second direction and are provided parallel to each other along the first direction, and the plurality of pixel circuits are arranged in a matrix form along the first and second directions, the first direction being a direction parallel to a direction in which the display unit is drawn out from the rolling mechanism. 
     In a seventh aspect, the display device further includes a position sensor configured to detect the unrolled area. 
     In an eighth aspect, a scanning signal is inputted only to at least one scanning wiring line corresponding to the plurality of pixel circuits included in the unrolled area, out of the plurality of scanning wiring lines. 
     In a ninth aspect, a control signal is inputted only to at least one light emission control wiring line corresponding to the plurality of pixel circuits included in the unrolled area, out of the plurality of light emission control wiring lines. 
     In a tenth aspect, the analog voltage signal is inputted only to at least one data signal wiring line corresponding to the pixel circuits included in the unrolled area, out of the plurality of data signal wiring lines. 
     In an eleventh aspect, the display device further includes a display control unit configured to control the display unit, wherein the display control unit is configured to determine at least one target pixel circuit to which a signal is inputted, out of the plurality of pixel circuits, based on detection results of the position sensors. 
     In a twelfth aspect, the display control unit is configured to determine a section of the unrolled area on which the image is to be displayed, based on a length of the unrolled area drawn out from the rolling mechanism and an aspect ratio of the image to be displayed on the display unit. 
     In a thirteenth aspect, only electro-optic elements provided in at least one of the plurality of pixel circuits included in the unrolled area, out of the electro-optic elements, emit light. 
     In a fourteenth aspect, the display unit further includes a terminal configured to receive a signal inputted from outside, wherein the terminal is provided at the lowermost edge portion. 
     In a fifteenth aspect, the terminal is provided on a back side opposite to a front side of the display unit, the front side being a side where an active area of the display unit is provided. 
     In a sixteenth aspect, the lowermost edge portion includes a side end portion parallel to a first direction, and a main end portion parallel to a second direction intersecting with the first direction, the first direction being a direction parallel to a direction in which the display unit is drawn out from the rolling mechanism. 
     In a seventeenth aspect, the display device further includes a plurality of first voltage wiring lines provided parallel to each other along a first direction, wherein the plurality of first voltage wiring lines extend from the first voltage primary wiring line to the pixel circuits in a second direction, and the first voltage primary wiring line is electrically connected to at least one pixel circuit arranged at the lowermost edge portion first, out of the plurality of pixel circuits, via the plurality of first voltage wiring lines. 
     In an eighteenth aspect, first switching elements are provided on the plurality of first voltage wiring lines. 
     In a nineteenth aspect, gate terminals of the first switching elements are electrically connected to the plurality of light emission control wiring lines corresponding one-to-one to the plurality of first voltage wiring lines. 
     In a twentieth aspect, second switching elements are provided on the first voltage primary wiring line. 
     In a twenty-first aspect, a curvature of the lowermost edge portion successively changes. 
     In a twenty-second aspect, the display device includes a first display unit and a second display unit as the display unit, and an active area of the second display unit is provided on an opposite side with respect to an active area of the first display unit. 
     In a twenty-third aspect, the display unit includes an Electro Luminescence (EL) display having a sheet shape. 
     Additional Notes 
     The disclosure is not limited to each of the embodiments stated above, and various modifications may be implemented within a range not departing from the scope of the claims. Embodiments obtained by appropriately combining technical approaches stated in each of the different embodiments also fall within the scope of the technology of the disclosure. Moreover, novel technical features may be formed by combining the technical approaches disclosed in each of the embodiments. 
     REFERENCE SIGNS LIST 
     
         
           1 ,  1   u ,  1   v ,  2 ,  3 ,  4  Display device 
           10 ,  20  Display unit 
           10   f  Display unit (first display unit) 
           10   r  Display unit (second display unit) 
           11 ,  11   f ,  11   r ,  11   fv ,  11   rv  Edge portion (lowermost edge portion) 
           12 ,  12   f  Terminal 
           16 ,  16   f ,  16   r  Position sensor 
           17 ,  17   u  Pixel circuit 
           110 ,  110   f ,  110   r ,  210  Rolling mechanism 
           151  Display control unit 
           170 ,  170   r ,  170   g ,  170   n  Light emitting element (electro-optic element) 
           191 H,  291 H First voltage primary wiring line 
           192 L Second voltage primary wiring line 
           900  Electrode (second electrode) 
           1111   h  Primary end portion 
           1111   s  Side end portion 
         Ar Display section 
         D 1  to Dm Data signal wiring line 
         E 1  to En Light emission control wiring line 
         S 1  to Sn Scanning wiring line 
         SS 1  to SSn Switching element (second switching element) 
         TTj Switching element (first switching element) 
         H 1  to Hm, HH 1  to HHn First voltage wiring line 
         La Length of rolled area 
         Lb Length of unrolled area 
         VDD Voltage (first voltage) 
         VSS, Vssr, Vssg, Vssb Voltage (second voltage)