Rangefinder apparatus
AssigneeFuji Photo Optical Co., Ltd.
InventorsYasuhiro Miwa, Tatsuo Saito
Life of this patent
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Abstract
In a rangefinder apparatus for projecting a light beam toward a target object a number of times; detecting light of the light beam reflected from the target object, and successively integrating output signals corresponding to the distance to the target object to carry out rangefinding; a voltage of an integrating capacitor in a rangefinding routine is detected, and the rangefinding routine is forcibly terminated if the voltage of the integrating capacitor is out of a preset range. Since the rangefinding routine is forcibly terminated if the voltage of the integrating capacitor in the rangefinding routine is outside of the preset range, malfunctions of a signal processing IC can be detected.
Claims8
A rangefinder apparatus comprising:
- light-projecting means for projecting a light beam toward a target object, located at a distance to be determined, a plurality of times;
- light-detecting means for detecting light of the light beam reflected from the target object and outputting a signal corresponding to the distance to the target object;
- signal processing means charging or discharging an integrating capacitor according to the signal output by said light-detecting means and outputting an integrated signal according to voltage of the integrating capacitor;
- detecting means for detecting the voltage of the integrating capacitor before rangefinding;
- and
- a central processing unit (CPU) controlling said light-projecting means, said light-detecting means, and said signal processing means, wherein, before rangefinding,
- said CPU controls said signal processing means to discharge the integrating capacitor,
- said CPU controls said detecting means to detect the voltage of the integrating capacitor after discharging of the integrating capacitor, and,
- when the voltage of the integrating capacitor detected by said detecting means is outside a fixed range, said CPU prevents said light-projecting means from projecting the light beam toward the target object.
Dependencies are inferred from the claim text.