Abstract: A cartridge consists of a case and a disk housed therein. The case has a case body in which a head access window and a drive spindle access window are formed. The case has a shutter to open and close the head access window and the drive spindle access window. The case body has in its rear side an opening through which the disk is taken out of and put into the case body. The opening is fitted with a lid that can be taken out of and put into the opening in the direction in which the disk is taken out of and put into the case body. One of the halves constituting the case body has a stopper removal hole, a stopper rest linked to the inner surface of the hole through thin bridges and formed seamlessly therewith, and a stopper whose one end is fixed on the inner surface of the stopper rest and which stops the lid from sliding.

Abstract: A cartridge consists of a case and a disk housed therein. The case has a case body in which a head access window and a drive spindle access window are formed. The case has a shutter to open and close the head access window and the drive spindle access window. The case body has in its rear side an opening through which the disk is taken out of and put into the case body. The opening is fitted with a lid that can be taken out of and put into the opening in the direction in which the disk is taken out of and put into the case body. One of the halves constituting the case body has a stopper removal hole, a stopper rest linked to the inner surface of the hole through thin bridges and formed seamlessly therewith, and a stopper whose one end is fixed on the inner surface of the stopper rest and which stops the lid from sliding.

Abstract: A hologram recording method wherein a transparent member for introducing a light beam into a recording material is designed so that the transparent member and the recording film can be uniformly brought into close contact with each other through an index matching liquid without damaging the recording film, and it is possible to stably carry out uniform and continuous exposure without failure of recording nor occurrence of unnecessary interference fringes. Also disclosed is a recorded hologram. A transparent member (3) is disposed at one surface of a recording film (2). A surface (5) of the transparent member (3) that is brought into close contact with the recording film (2) is convexly curved only in the direction of feed of the recording film (2). In addition, the space between the contact surface (5) and the recording film (2) is filled with an index matching liquid (4) so that the recording film (2) is brought into close contact with the transparent member (3) through the index matching liquid (4).

Abstract: A method for producing a thick film type of non-fogging sheets having a thickness of 30 .mu.m or more comprises the steps of: preparing a solvent-free composition comprising (a) a polymer, (b) a hydrophilic monomer and (c) a surface active agent and having a viscosity of 50,000 cP or less, applying this composition as a coating on the surface of a backing film without recourse to any solvent, and crosslinking the thus coated composition by exposure thereof to ionizing radiation, thereby forming a hydrophilic film having a thickness of 30 .mu.m or more.