Seiko Precision Inc.

Teruyo Miyata

Hiroyuki Saito

Yoichi Seki

Akira Ito

Tetsumi Kaneoka

In order to improve the accuracy and reliability of a distance measurement device of the light-projecting type, the device is provided with a reference voltage generator for generating a reference voltage having a level dependent upon whether or not a light is being projected. The distance measurement device includes a light projecting circuit for projecting pulsed light onto an object, a light receiving circuit for receiving the light projected by the light projecting circuit and reflected by the object, current-to-voltage conversion circuitry for converting a current output by the light receiving circuit into a corresponding voltage, amplifier circuitry for amplifying the output signals of the current-to-voltage conversion circuits, an integration circuit for integrating the output signal of the amplifier circuit, a level judgement circuit for judging the level of the output signal of the integration circuit by comparing it with a reference voltage, and an arithmetic circuit for switching the reference voltage depending on whether the light-projecting circuit is projecting light and for calculating the distance of the object based on the output of the level judgement circuit.

Distance measuring device

A camera with a battery checking function is provided with a timer for generating an output signal at predetermined time intervals, a memory for storing a calculated time value, an external switch for generating an activating signal for activating the camera, and a microcomputer for activating the camera in response to the activating signal generated by the external switch, for updating the content of the memory in accordance with the output of the timer at first time intervals when the camera is activated, for placing the camera in a standby mode when the activating signal has not been detected for a predetermined period of time, and for updating the content of the memory in accordance with the output of the timer means at second time intervals, longer than the first time intervals, when the camera is in a standby mode. A voltage detector detects the voltage of a battery at third time intervals when the camera is activated and detects the voltage of the battery at fourth time intervals when the camera is in the standby mode. A display indicates the charge level of the battery.

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Yotsukaido, Japan

Teruyo Miyata