Nippon Pillar Packing Co., Ltd.

Pillar Inc.

Kentaro Watanabe

Akira Nakatsu

The resistance detection sensor is configured to detect the electrical resistance value of a liquid. This resistance detection sensor includes a pair of electrodes, a DC voltage application unit, an AC voltage application unit, and a control unit. The pair of electrodes are immersed in a liquid. The DC voltage application unit applies a DC voltage having a first polarity between the pair of electrodes. The AC voltage application unit applies an AC voltage between the pair of electrodes. The control unit calculates the electrical resistance value of the liquid, in a state where the DC voltage is applied between the pair of electrodes by the DC voltage application unit. The control unit controls the AC voltage application unit so as to apply an AC voltage starting from a second polarity opposite to the first polarity at a predetermined time interval between the pair of electrodes. The time period for which the AC voltage is applied between the pair of electrodes by the AC voltage application unit is not an integer multiple of the cycle of the AC voltage applied between the pair of electrodes.

Resistance detection sensor

Provided is a liquid sensor or the like that is relatively easy to manufacture. The liquid sensor includes a light emitting element, an optical waveguide, a light receiving element, and a detection circuit. The optical waveguide includes a first pillar portion, a first metal plate, a second pillar portion, and a second metal plate. The first metal plate is embedded in the first pillar portion. The second pillar portion is provided at a position opposing the first pillar portion. The second metal plate is embedded in the second pillar portion. A space for liquid is formed between the first pillar portion and the second pillar portion. The first pillar portion includes a first end surface that faces the light emitting element. The first metal plate includes a first reflecting portion that is tilted relative to the first end surface and reflects light toward the second pillar portion. The second pillar portion includes a second end surface that faces the light receiving element. The second metal plate includes a second reflecting portion that is tilted relative to the second end surface and reflects the light from the first metal plate toward the light receiving element.

Liquid sensor and method for manufacturing optical waveguide

Provided is a liquid sensor that can more accurately detect the state of a liquid. The liquid sensor includes a light emitting element, an optical waveguide, a light receiving element, and a detection circuit. The light receiving element is configured to receive light that was emitted by the light emitting element and passed through the optical waveguide. The detection circuit is configured to detect output of the light receiving element. The optical waveguide includes a first pillar portion that extends straight and a second pillar portion that extends straight. The second pillar portion is provided at a position opposing the first pillar portion. A space for liquid is formed between the first pillar portion and the second pillar portion. The first pillar portion includes a first end surface that faces the light emitting element, and a second end surface that is tilted relative to the first end surface and reflects light toward the second pillar portion. The second pillar portion includes a third end surface that faces the light receiving element, and a fourth end surface that is tilted relative to the third end surface and is configured to reflect light from the second end surface toward the light receiving element.

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Osaka, Japan

Kentaro Watanabe