Projection system

Claim 1

A projection system having a compressed optical path for projecting diapositive film strips comprising: a projection box having a plurality of walls including one wall in the form of a ground glass plate and at least another wall transversely disposed to said one wall, said one wall in the form of a ground glass plate acting as a screen for rear view projections; projector means for providing a projection beam having a principal ray, said projector means being disposed adjacent to said another wall at a location thereon remote from said one wall and including illumination means for generating said projecting beam and an objective having a relatively short focal length for focusing an image being projected upon said one wall, said illumination means having an optical axis along which said principal ray is produced and said objective having an optical axis, an optical center and an imaging cone for incoming radiation provided by said illumination means, said objective having said optical axis thereof parallelly disposed to said another wall and transversely disposed to said one wall and said illumination means being positioned having said optical axis thereof being inclined toward said another wall in a direction in which said principal ray is produced and passing through said optical center of said objective to form an acute angle with said optical axis of said objective and said another wall, said acute angle being limited to enable said projecting beam from said illumination means to be substantially within said imaging cone for incoming radiation; and first and second reflecting mirrors being disposed within said projection box and arranged to project said projecting beam upon said one wall, said first and second reflecting means being substantially parallelly disposed.