Portable information device case and video picture display device case

A video picture display device case comprising:

• an enclosure for housing a display therein;
• and
• an image-forming optical element,
• the enclosure including a top plate member provided with the image-forming optical element and at least two side plate members each having an upper part supporting the top plate member.
• wherein, when the case is in a usage form in which the top plate member and the two side plate members are combined together to have a predetermined shape, the image-forming optical element is disposed in the upper surface of the top plate member of the enclosure, a display mounting surface that is an inner surface of the side plate members is provided under the image-forming optical element, and the display is held on the display mounting surface, with a display surface of the display held in an attitude inclined at a predetermined angle with respect to the lower surface of the image-forming optical element, so that a video picture on the display surface of the display transmitted through the image-forming optical element is image-formed over the image-forming optical element in a manner floating up.