The ornamental design for a displaydevice, as shown and described.
FIG. 1 is a front perspective view of a display device showing our new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a left side elevation view thereof;
FIG. 5 is a right side elevation view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is another front elevation view thereof showing additional unclaimed environment.
The dashed broken lines in the figures represent portions of the display device, or are for environmental purposes only, and form no part of the claimed design. The dot-dash broken lines in the figures represent an unclaimed boundary line and form no part of the claimed design.