The ornamental design for a displaydevice, as shown and described.
FIG. 1 is a perspective view of the display device in a folded state;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top view thereof, with the bottom view being a mirror image;
FIG. 7 is an another perspective view thereof;
FIG. 8 is a perspective of the display device in an unfolded state;
FIG. 9 is a front view thereof;
FIG. 10 is a rear view thereof;
FIG. 11 is a left side view thereof;
FIG. 12 is a right side view thereof;
FIG. 13 is a top view thereof, with the bottom view being a mirror image;
FIG. 14 is another perspective view thereof;
FIGS. 15 to 16 illustrate that images can be displayed on the screen of the display device, but the images are shown for reference only and form no part of the design; and,
FIGS. 17 and 18 represent the display device when the display device is in a partially unfolded state.
The broken lines shown in the drawings are for illustrative purposes only and form no part of the claimed design.