A display device of the present invention is configured in such a manner that a liquid crystal module is inserted in the inside of a positioning frame that is attached to a top window. The method includes initiating a predetermined uncontrolled liquid fuel prefill flow rate through the liquid fuel system, sensing an onset of the uncontrolled liquid fuel flow to the combustor nozzles, and initiating transfer from gas fuel operation to liquid fuel operation when the flow of uncontrolled liquid fuel at the combustor nozzles is sensed. Similarly, the fixity members are held by the insulator. It will thus be possible to place and anchor one tile assembly in relation to another in as many positions as the number of sides of the tiles. Reflected light from the \u201cON\u201d and \u201cOFF\u201d states are thus separated and the contrast ratio is improved. The side of the slot facing the bottom surface during use includes a lower surface which is inclined at an angle which is at least virtually equal to the angle of inclination of the inclined bottom surface and, in coupled condition, abuts at least against a planar central part of the inclined bottom surface.