Abstract: A birefringent film with excellent uniformity in in-plane retardation, retardation in the thickness direction, and alignment axis is provided. The birefringent film is produced in such a manner that, in the step of stretching a polymer film, the polymer film is stretched in a width direction while being shrunk in a longitudinal direction, and assuming that lengths in the width direction and the longitudinal direction of the polymer film before being stretched are 1, a change ratio (STD) of the length in the width direction of the polymer film resulting from the stretching and a change ratio (SMD) of the length in the longitudinal direction of the polymer film resulting from the shrinking satisfy the following formula (1).

Abstract: The invention provides a polarizing film comprising: a long polymer film; and a dichroic substance, wherein the polarizing film has an absorption axis in the TD direction of the polarizing film.

Abstract: A retardation-film integrated polarizing plate includes a polarizing plate stretched in a lengthwise direction thereof and having an absorption angle in the lengthwise direction, and a uniaxial retardation film having a slow axis in a widthwise direction thereof and an Nz coefficient of 0.9-1.1, in which the polarizing plate is laminated with the uniaxial retardation film so as to have the slow axis of the retardation film oriented at an angle of 90 degrees plus or minus 5 degrees to the absorption axis of the polarizing plate. The thus arranged polarizing plate is capable of enhancing the front contrast and the contrast at oblique viewing angles.

Abstract: A method of manufacturing a birefringent film includes stretching a polymer film in a widthwise direction while at the same time shrinking the same in a lengthwise direction so as to satisfy the relational expression: (1/STD)1/2?SMD<1, in which the length in the widthwise direction and the length in the lengthwise direction, of the polymer film before being stretched are respectively designated as 1, and STD represents a change ratio of the length in the widthwise direction of the polymer film due to stretching and SMD represents a change ratio of the length in the lengthwise direction of the polymer film due to shrinking, and make the stretched polymer film have an Nz coefficient of 0.9-1.1.

Abstract: The invention provides a fuel cell which comprises a solid polymer electrolyte sandwiched between a cathode to which an oxidizing agent gas is supplied and an anode to which a reducing agent gas is supplied, wherein at least one of the electrodes has an electroconductive organic polymer which has an oxidation-reduction function as an electrode catalyst. The invention further provides a fuel cell in which the electrode catalyst comprises a mixture of an electroconductive organic polymer and an inorganic oxidation-reduction catalyst, and has a higher output power.

Abstract: When a fiber optic endoscope is exposed to X-ray or .gamma.-ray irradiation, the fiber bundle becomes discolored and there is thus a reduction in light transmittance. This makes observation or examination difficult or impossible. The irradiation-induced reduction in light transmittance of the image transmitting fiber bundle is restored, according to this invention, by visible light radiation endwise therethrough. Visible light radiation having a short wavelength largely restore the light transmittance to that before irradiation in a short period of time.

Abstract: An illumination optical system using optical fiber bundles. The optical fiber bundles are assembled to form an illumination optical system. The exit end faces of the fiber bundles are flat and inclined in different directions to effect a diverging illumination light flux as a whole.

Abstract: An image transmitting optical fiber bundle has at an end of it a field stop for defining the size of image viewed thereby. The field stop is sandwiched between a pair of transparent thin plastic films. The pair of films which sandwiches the field stop is fixed to an end of the optical fiber bundle. A face plate is further fixed on the pair of films on the end face of the fiber bundle. Since the surfaces adhered are all flat, the formation of bubbles in the adhesive is easily precluded.