Abstract: A process for forming a thin film is described that enables automatic formation of thin films having constant optical properties reliably and in large quantities with excellent reproducibility suitable for mass production. An apparatus for performing the process is also described. Generally, a material for vapor deposition is vaporized by an electron gun and an antireflection film forms by vapor deposition on lenses held by a coat dome. The electric power applied to the electron gun is controlled so that the amount of transmitted or reflected light continuously measured by an optical film thickness meter during thin film formation is compared to a reference amount of measured light stored in a means for storing data until the measured and reference amounts of measured light are close to, or the same as, one another.

Abstract: Hybrid films, such as those having good abrasion-resistance and defogging properties, antireflection films including it, optical products, and methods for restoring the defogging property of the hybrid films are disclosed. The hybrid films having a defogging property may be obtained through vapor deposition of an organic compound having a hydrophilic group and a reactive group along with silicon dioxide or with silicon dioxide and aluminum oxide. The antireflection film may be formed on a substrate having the hybrid film as the outermost layer opposite to the substrate. The optical product may comprise a plastic substrate and the antireflection film having the hybrid film. A method for restoring the defogging property of the hybrid film of the optical product may include washing the hybrid film.

Abstract: A vapor deposition crucible includes a crucible main body which is open to upper and lower sides and has a cavity in which a sintered pellet as a vapor deposition material is stored. The cavity of the crucible main body has two cavity portions. A first cavity portion connected to an opening open to the lower side is formed to make the sintered pellet to be stored fit in the first cavity portion. A second cavity portion connected to an opening open to the upper side is formed to form a gap between the second cavity portion and the sintered pellet to be stored. A step like portion is at least partially formed at a connection portion between the first cavity portion and the second cavity portion.

Abstract: An optical element having a plastic substrate and an antireflection film of a &lgr;/4-&lgr;/2-&lgr;/4 or &lgr;/4-&lgr;/4-&lgr;/2-&lgr;/4 type (&lgr;=500 nm) provided in that order on the plastic substrate, wherein the layer of &lgr;/2 is a high-refraction equivalent film containing at least three layers and having a refractive index of from 1.80 to 2.40, and the even-numbered layer(s) of the equivalent film is an SiO2 layer or a layer in which SiO2 is a main component.

Abstract: A method for producing a composition for vapor deposition comprising sintering a vapor source mixture prepared by mixing vapor sources that contain titanium dioxide and niobium pentoxide. The method is capable of forming a high-refraction layer even in low-temperature vapor deposition on a substrate. An antireflection film is formed having good scratch resistance, good chemical resistance and good heat resistance, of which the heat resistance decreases little with time, that is useful in a variety of optical elements.

Abstract: A method for producing an optical element having a multi-layered antireflection film formed on a synthetic resin substrate, in which the antireflection film formed has good heat resistance, and its heat resistance lowers little with time. At least one high-refraction layer of the multi-layered anti-reflection film contains niobium oxide, zirconium oxide, yttrium oxide, and optionally aluminum oxide. High-refraction layers can be formed within a shorter period of time while not detracting from the good physical properties intrinsic to the layers.

Abstract: An optical element having a plastic substrate and an antireflection film of a &lgr;/4-&lgr;/2-&lgr;/4 or &lgr;/4-&lgr;/4-&lgr;/2-&lgr;/4 type (&lgr;=500 nm) provided in that order on the plastic substrate, wherein the layer of &lgr;/2 is a high-refraction equivalent film containing at least three layers and having a refractive index of from 1.80 to 2.40, and the even-numbered layer(s) of the equivalent film is an SiO2 layer or a layer in which SiO2 is a main component.

Abstract: An optical element having a plastic substrate and an antireflection film provided on the plastic substrate, characterized in that the optical element has a basic layer comprising Nb between the plastic substrate and the antireflection film. The optical element has high adhesiveness between the plastic substrate and the antireflection film and is characterized by excellent resistance to heat, impact, alkali, and abrasion.