Agency of Industrial Science and Technology

Ministry of International Trade & Industry

Naotake Ooyama

Kiyofumi Matsuda

Thomas H Barnes

Takashi Imai

Shuntetsu Matsumoto

Kiyoko Shigeta

A high stability interferometer is capable of continuous measurement of small changes in the refractive index of a sample. The interferometer has a diffraction grating placed to be movable sideways or radially, and diffract laser light into beams which include +1, -1 and zero order beams. The diffraction grating is in the input plane of a Fourier Transform lens. The beams are brought to a focus in the output plane of the lens and are reflected back towards the lens by a mirror placed in the transform plane of the lens. The sample whose refractive index is to be measured is placed in the path of the +1 or -1 order beam, between the diffraction grating and the mirror.

High stability interferometer for measuring small changes in refractive

Optical spatial phase modulation is achieved by positioning a liquid crystal layer in the path of a light beam to be modulated and controlling the spatial distribution of refractive index of the liquid crystal layer by controlling the spatial distribution of the electrical field generated across the liquid crystal layer.

Method and device for achieving optical spatial phase modulation

The system for collection and transmission of road traffic information comprises a lens system installed on a tall structure such as on the roof of a building and angled vertically or diagonally to include in its field of view a road area subjected to observation and a plurality of photoelectric conversion elements disposed on the focal plane of the lens system along the image of the road area to be formed on the focal plane. The plurality of photoelectric conversion elements are formed in shapes successively decreased in width and length in conformity with the perspective view of the road area formed on the focal plane of the lens system. This system operates on the principle that when a vehicle enters the road area under observation by this system, it causes a change in the brightness of the image of the road area formed on the focal plane of the lens system, the changed brightness of the image induces a corresponding change in the outputs of the photoelectric conversion elements, and the resultant change in the outputs on being processed by scanning gives rise to a series of pulse signals, which are transmitted to a traffic control center.

Growing community of inventors

Tsukuba, Japan

Naotake Ooyama