Alps Electric Co., Ltd.

Ikuo Ouchi

Kazuo Hasegawa

Hisashi Murata

Junichi Ouchi

Hironobu Watanabe

This invention relates to a photoelectric switch and a photoelectric detector for detecting the presence or absence of an object by using a light, and more particularly to prevention of mutual interference in the case of using a plurality of photoelectric switches. For example, an LED in a light emitting unit intermittently emits a sensing light at the timing of an output pulse from a pulse generator. The resultant pulse is divided in frequency by a frequency divider and then delayed by a one-shot circuit. At the timing of an output pulse from the one-shot circuit, another LED emits a transmission light to a photoelectric switch at next stage. Therefore, the transmission light is always delayed from the sensing light. The transmission light from the preceding photoelectric switch of the same construction is received by a photodiode, and an output pulse is outputted from a pulse generator in synchronism with a synch timing signal produced from the light receiving unit. Thus, the sensing lights from the respective photoelectric switches are emitted at the timings shifted from one another through delays effected by the one-shot circuits.

Photoelectric switch including synch timing signal emitter and detector

An illumination type optical recorded information reading device including a plurality of light emitting elements, a photo detector for detecting optical indication on a media and converting the detected indication to electrical information, a plurality of driving elements for driving the light emitting elements, a driving current detector for detecting a total value of driving currents flowing through the driving elements, and a controller for comparing the total value with a reference value and generating a control signal to the driving elements so as to make a difference between the total value and the reference value constant. Further, a distribution of an illuminance of the light to be applied to the media is set in such a manner that the illuminance at positions spaced away from a central portion of a maximum detectable range of the photo detector is higher than that at the central portion, and that the illuminance at opposite end portions of the maximum detectable range is lower than that at the positions spaced away from the central portion.

Illumination type optical recorded information reading device

In a code reading device, which receives reflected light obtained by scanning a code represented on a recording medium with a laser light beam and decodes it to obtain the code, the reading probability is improved by varying the focusing position for every scanning period with the laser light beam.

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Miyagi, Japan

Ikuo Ouchi