Optical apparatus, film to be provided on surface of optical apparatus, paint to be used for optical apparatus

#The present invention relates to a film and paint to be provided on a lens barrel of an optical apparatus such as a camera, a video camera, a broadcasting device or the like, and on the surface of an optical apparatus such as a camera main body, a video camera main body, a surveillance camera, a weather camera or the like to be possibly used outdoors, and to an optical apparatus.

#A film to be provided on the surface of an optical apparatus is a film which has a function of suppressing a temperature rise of a member due to sunlight when it is used outdoors. Conventionally, as a method of suppressing the temperature rise of the member due to sunlight, as illustrated in FIG. 1, there has been known a method of reflecting incident light 1 by the sun as reflected light 2 by an infrared reflection film 4 on a base material 5′. In this method, heat generation due to transmitted light 3 can be suppressed by increasing a ratio of the reflected light 2 to the incident light 1. As a material to be used for increasing a reflectance, titanium oxide having a high reflectance from a visible light region to an infrared region is often used. In addition, a solar energy distribution is 47% in the visible light region and 50% in the infrared region, so that a high reflectance in a wide range from the visible light region to the infrared region is required.

#Besides, since the optical apparatus is often used outdoors, in addition to heat-shielding performance, also lightfastness (light resistance) under a severe sunlight condition such as a midsummer condition, an equatorial condition or the like is required. Moreover, there is a case where a tape such as a cellophane adhesive tape, a masking tape, a gummed tape, a Tepra™ tape or the like may be stuck to a part of the surface of the film provided on the surface of the optical apparatus. On this account, in some cases, the lightfastness is required also when oxygen is no longer supplied from the outside because the tape has been stuck and thus it becomes an anoxic state.

#FIG. 1 is a cross-section schematic diagram for illustrating a state of reflection and absorption of sunlight when a film to be provided on the surface of an optical apparatus is formed on an upper surface of a base material.

#FIG. 2 is a cross-section schematic diagram for illustrating a state that sunlight is irradiated to a film made of titanium oxide and a resin.

#FIG. 3 is a cross-section schematic diagram for illustrating a state that sunlight is irradiated to a film made of titanium oxide coated with second silica, and a resin.

#Preferred embodiments of the present invention will now be described in detail in accordance with the accompanying drawings.

#First, a method of suppressing discoloration and reflectance deterioration in an anoxic atmosphere will be described. Then, paint (coating material) to be formed on the upper surface of an optical apparatus for suppressing the discoloration and the reflectance deterioration in the anoxic atmosphere, a film to be formed on the upper surface of the optical apparatus for the same purpose, and the optical apparatus will be described.

#[Method of Suppressing Discoloration and Reflectance Deterioration in Anoxic Atmosphere]