Hitachi, Ltd.

Sachiko Okuzaki

Ken Takahashi

Motoyasu Terao

Takashi Naito

Hiroki Yamamoto

Toshimichi Shintani

Sumio Hosaka

Fumiyoshi Kirino

Takashi Namekawa

Tetsuo Nakazawa

Eiji Koyama

Masahiro Nishizawa

Takao Ishikawa

Tomoji Oishi

Norikazu Uchiyama

Daigoro Kamoto

The object of the present invention is to provide an optically functional element having a large change in refractive index with temperature change and a fast change rate in refractive index, a production method for the same and optical switch, temperature sensor and optical information recording medium using the same. The present invention provides a thin film formed directly on a substrate or via other layers, and the film is composed of particles with an average diameter of not larger than 13 nm, observed at film surface. The present invention also provides an optically functional element having an amount of change in refractive index of not less than 2.0&#xd7;10/&#xb0; C. The present invention further provides a production method for said thin film by sputtering under reduced pressure in an inert gas atmosphere containing 3-15% by volume of oxygen, and optical switch, temperature sensor and optical information recording medium using said element.

Optically functional element and production method and application therefor

An anti-reflection film is in the form of a laminated film composed of an uppermost film layer containing coloring matter having an absorbing peak in a region near the infrared region of 700 nm-900 nm, or coloring matter having an absorbing peak in a region of 600 nm-700 nm, or both of the above coloring matter, and the next film layer to the uppermost layer containing coloring matter having an absorbing peak in a region of 500 nm-600 nm. The anti-reflection film utilizes a variation of the refractive indexes based on abnormal refractive index dispersion by the films containing the coloring matter. The anti-reflection film having a low reflectivity all over the visible light region can be manufactured by utilizing the abnormal refractive index dispersion of the next layer to the uppermost layer caused by an absorption of red coloring matter and a balance with the refractive indexes of the uppermost layer containing red color matter having an absorption in the region near the infrared wavelength, or blue coloring matter, or both of the above coloring matter. Furthermore, red coloring matter, having an absorbing peak in the region of 500 nm-600 nm and contained in the next layer to the uppermost layer, absorbs side bands of green and red, and accordingly, color purity is improved.

Anti-reflector film, and a display provided with the same

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Hitachi, Japan

Sachiko Okuzaki