Kabushiki Kaisha Toshiba

Hironori Fukuda

Tomokazu Domon

Kenji Sano

Taeko I Urano

Hideo Nagai

Masashi Sahashi

Koichiro Inomata

Tadahiko Kobayashi

An article including a substrate and an invisible symbol on the substrate is disclosed. The invisible symbol is formed by a compound which includes a cyano group and has an infrared absorption wavelength apart from that of the substrate when heated.

Method and apparatus for reading invisible symbol

An invisible symbol reading apparatus includes a heating unit for heating an invisible symbol formed on a sample and containing a material which emits infrared light when heated, a detecting unit for detecting infrared light emitted from the invisible symbol, and an arithmetic operation unit for binarizing a detection signal from the detecting unit. The arithmetic operation unit calculates a differential coefficient of the detection signal, that corresponds to a position on the sample. On the basis of upper and lower threshold values set for the differential coefficient, the arithmetic operation unit determines a maximum value of the differential coefficient in a region exceeding the upper threshold value and a minimum value of the differential coefficient in a region smaller than the lower threshold value. The arithmetic operation unit binarizes the detection signal by using the maximum or minimum value as a leading or trailing edge of a binary function.

In a torque sensor of a noncontact type for sensing a torque applied to a shaft, a magnetic ribbon is bonded to a circumferential portion of the peripheral surface of the shaft, and a core member made of a magnetic material is arranged above the shaft surface so that its end faces are faced to the magnetic ribbon. A exciting coil and a detecting coil wound around the core so that a magnetic flux produced by the exciting coil and delivered to the detecting coil is detected by the detecting coil. The magnetic ribbon has a length L0 equal to or smaller than one half of the circumferential length Ls of the shaft 4 and satisfying an inequality given by

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Kawasaki, Japan

Hironori Fukuda