A memory device and a method for managing the memory device is provided. The display device is thus capable of preventing copyright protected video data from being copied by imaging the screen image of the video data at low cost. The curved surface of the mask body is disposed a predetermined distance apart from a curved surface of the roll. A first RF electrode extends over the first waveguide and a second slotted electrode including a first section extends over the second waveguide. Dimensions for baffle array symmetry or asymmetry, parallel spacing, baffle thickness and baffle inset from one of the duct openings are chosen to restrict distance between adjacent baffles to less than a wavelength of windage noise at selected propagation frequencies, yet provide for sufficient cooling airflow through the duct.