Photography – With exposure objective focusing means – focusing aid – or... – Having auxiliary illumination
Reexamination Certificate
1999-09-15
2001-01-09
Perkey, W. B. (Department: 2851)
Photography
With exposure objective focusing means, focusing aid, or...
Having auxiliary illumination
C396S120000, C396S129000, C356S003040
Reexamination Certificate
active
06173123
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a rangefinder apparatus used in a camera or the like.
2. Related Background Art
In an autofocus mechanism (AF mechanism) of a camera or the like, a rangefinder apparatus for measuring the distance to an object by a trigonometric system is used in general. In this rangefinder apparatus, a light-emitting device projects an infrared ray toward the object, a light-receiving device receives reflected light of the ray and outputs a signal according to a position at which the light is received, and a signal processing circuit or the like measures the distance to the object according to this signal.
In the rangefinder apparatus, since a predetermined power source voltage is necessary for actuating the signal processing circuit and the like, the voltage of the battery contained in the camera is raised by a step-up regulator, and thus raised voltage is supplied to the signal processing circuit and the like.
SUMMARY OF THE INVENTION
However, the above-mentioned rangefinder apparatus has a problem that it may fail to obtain accurate range-finding results.
Therefore, it is an object of the present invention to resolve this problem and provide a range finder apparatus which can carry out accurate range-finding.
In order to achieve this object, the rangefinder apparatus in accordance with one aspect of the present invention comprises light-emitting means for projecting a ray toward a range-finding object; light-receiving means for receiving reflected light of the ray projected from the light-emitting means to the range-finding object and outputting a signal according to a position at which the light is received; arithmetic means for carrying out an arithmetic operation according to the signal from the light-receiving means and outputting a signal corresponding to a distance to the range-finding object; integrating means for integrating the signal from the arithmetic means by discharging or charging an integrating capacitor a plurality of times with a predetermined period in response to the signal from the arithmetic means, so as to output a signal corresponding to a result of the integration; detecting means for detecting the distance to the range-finding object according to the signal from the integrating means; a battery for supplying a power source voltage; and step-up means for raising the power source voltage of the battery through an oscillating action and outputting thus raised voltage; wherein the raised voltage is supplied to at least one of the light-emitting means, light-receiving means, arithmetic means, integrating means, and detecting means; and wherein the predetermined period of the integrating means is kept from being a constant period.
The rangefinder apparatus in accordance with another aspect of the present invention comprises light-emitting means for projecting a ray toward a range-finding object; light-receiving means for receiving reflected light of the ray projected from the light-emitting means to the range-finding object and outputting a signal according to a position at which the light is received; arithmetic means for carrying out an arithmetic operation according to the signal from the light-receiving means and outputting a signal corresponding to a distance to the range-finding object; integrating means for integrating the signal from the arithmetic means by discharging or charging an integrating capacitor a plurality of times with a predetermined period in response to the signal from the arithmetic means, so as to output a signal corresponding to a result of the integration; detecting means for detecting the distance to the range-finding object according to the signal from the integrating means; a battery for supplying a power source voltage; and step-up means for raising the power source voltage of the battery through an oscillating action and outputting thus raised voltage; wherein the raised voltage is supplied to at least one of the light-emitting means, light-receiving means, arithmetic means, integrating means, and detecting means; and wherein the predetermined period of the integrating means is asynchronous to an oscillating period of the step-up means.
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not to be considered as limiting the present invention.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
REFERENCES:
patent: 5832324 (1998-11-01), Shimizu et al.
patent: 7-181038 (1995-07-01), None
patent: 7-229735 (1995-08-01), None
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