A corner piece for covering or capping a structure corner adjacent shake shingle siding characterized by a lineally variable contour includes a field modifiable trim strip for reflecting and accommodating the contour of the siding adjacent the structure corner. The sheet feeding portion feeds envelopes one-by-one in a state where the envelopes are stacked on a sheet feed table and a rear end portion opposite to a flap portion formed in a front end portion of each of the envelopes is set to a leading portion in a sheet feed direction. With the support yokes struck down into their storage positions, the collapsed container takes on a minimum space configuration and can be densely stored or transported. The gain compensator generates the charge pump reference current by replicating a reference scale current using unit current sources. The first insulating layer is disposed between the flexible substrate and the first patterned conductive layer and directly contacts the flexible substrate. At this time, the lower and lateral sides of the display device are covered without using upper and external cases to cover the upper edge of display device.