The invention provides a method and apparatus to obtain accurate gradation by obtaining an accurate ratio of light emitting parts in a display device which implements gradation by forming a plurality of TFTs and a plurality of OELDs in each pixel, directly connecting the TFTs and OELDs, and switching an on and off state of the TFTs, and controlling a light emitting area of the OELDs. In one aspect, a coil is configured generate a voltage in response to magnetic field generated by a transmitter. An inlet hopper is connected to the inlet opening and a blow back shield is mounted in the upper end portion of the hopper with the shield including an outer layer of clear synthetic material extending across the hopper and an inner layer of synthetic material extending part way underneath the length of the layer of clear synthetic material.