Abstract: A film jacket comprising a base sheet, one or more transparent surface sheets, each having three edges thereof fixed to the base sheet so as to form pockets, and cover members fixed to the base sheet for covering extended portions of films outside the pockets, whereby firmly holding films at desired positions.

Abstract: The disclosed film viewer comprises a box with a bottom and an inclined top having a diffusion plate fitted therein, a light source disposed in the box, and a number of reflectors distributed on the inner surface of the box so as to reflect light beams from the light source in such a manner that uniform brightness is provided throughout the entire surface of the diffusion plate.

Abstract: The disclosed sheet has a plurality of rectangular recesses in rows and columns for holding one transparency in each recess, and an inclined surface portion is formed substantially at the center of the bottom wall of each rectangular recess, so that reflection from the center of the bottom wall of the recess is angularly deviated from reflection from the center of the transparency held by the recess.

Abstract: The disclosed structure holds a rectangular thin-piece such as a photographic transparency on a base sheet between at least two holding portions formed on the base sheet and a thin-piece seat being recessed relative to the holding portions. A push-in area is formed on the base sheet adjacent to both the seat and at least one of the holding portions. One edge of the thin-piece is once pushed in between the push-in area and the holding portion adjacent thereto to an extent sufficient for clearing the thin-piece from the remainder of the holding portions, and then the thin-piece is moved back from the push-in area onto the seat where an abutting member abutts the thin-piece to keep the thin-piece in position. A plurality of the thin-piece holding structures are formed on one base sheet to form a slide filing sheet.

Abstract: A disclosed projector includes a condenser lens, a plurality of light source means having different focal lengths and disposed around the condenser lens, a projecting lens with an adjustable distance from the condenser lens, and a stage glass located between the condenser and projecting lens for carrying a transparent positive thereon. Depending on the size of the transparent positive, one of the light source means is selected and the distance between the condenser and projecting lens is adjusted, so as to project an image of substantially fixed magnitude with a constant brightness regardless of said size of the transparent positive.

Abstract: An overhead projector comprises a stage having at least two guide members fixed to its upper surface and movable longitudinally and transversely above a projector body, a file page having a plurality of slide films fitted therein in rows and columns and pairs of reference edges spaced apart at equidistances from crosswise and lengthwise center axes of the file page and adapted to abut against the guide members of the stage for positioning the file page relative to the stage, and positioning means for determining movements of the stage at determined intervals. The slide films in the file page are spaced apart at distances correspondingly equal to the movement distances determined by the positioning means. The projector is capable of correctly positioning a file page relative to the stage with ease after the file page has been rotated or turned upside down for changing over the projection methods of the projector, such as reflection projection and transmission projection.