Abstract: A display device includes a projector and a translucent hemispherical screen disposed in a black box, with the axis of the hemisphere extending perpendicular to a surface on which an image from the projector is cast. A semitransparent mirror is disposed on the opposite side of the image-receiving surface of the hemispherical screen, aslant to the axis of the hemisphere and opposite a viewer. The image of an spherical object projected on the hemispherical screen can be seen in stereoscopic spatial vision. The image viewed through the semitransparent mirror appears as if it was floating in space.

Abstract: A method and apparatus for forming a fog screen for use in the projection for display of an optical image which comprises disposing a pair of substantially parallel air curtains and blowing a fog into the space defined by and between the air curtains. The fog screen is high and uniform in density and can be utilized for forming a well-defined image thereon that is free from distortions or interruptions.

Abstract: An air floater comprises a balloon body which seals a gas therein and balancing means detachably attached to the balloon body. The balloon body comprises a film composed of a central layer made of ethylene-vinyl alcohol copolymer-resin, an aluminum evaporated layer provided outside the central layer, and a heated adhesive layer provided inside the central layer. The balancing means comprises a plurality of magnetic cards which are attracted by an attraction portion composed of a magnetic body attached to the balloon body. The plurality of magnetic cards includes one card having a reference weight matched with the buoyant force of the balloon body, first weight balancing cards having weight heavier by stages than the reference weight, and second weight balancing cards having weight lighter by stages than the reference weight. The balancing means may comprise sublimate sealed in a bag body.