A rollable display device includes a display panel for displaying an image, a printed circuit board connected to an edge of the display panel, and a roller which the display panel is rolled onto or unrolled from. The roller has a cylindrical shape having an inner space, and the printed circuit board is disposed in the inner space.

Disclosed are techniques for reducing out-of-plane protrusions while singulating an electrode from a web. In some embodiments, feed rollers feed perforated web material from a roll, tear and position rollers receive a portion of the perforated web material from the feed rollers, and a servo motor changes speed of at least one of the feed rollers and tear and position rollers to thereby generate a tearing force, applied to the portion of the perforated web material, that singulates the portion in a predefined shape of an electrode.

A canvas cover launching device to prevent crimps on the canvas and achieve flattening effect on the canvas, having a frame and a mounting rack on one side, a hydraulic control valve operated by control levers is on the mounting rack. Two driving plastic rollers and a surface smoothening plastic roller are rotatably connected to the frame from inside to outside of the frame sequentially; corresponding ends of the two driving plastic rollers on a same side are connected to a transmission component enabling the two driving plastic rollers to rotate towards the same direction. A synchronous transmission gearbox is provided to connect corresponding ends on a same side of the surface smoothening plastic roller and one of the two driving plastic rollers more proximal to the surface smoothening plastic roller. Hooked plates are symmetrically provided on two ends of the surface smoothening plastic roller respectively.