Photo detecting apparatus for detecting reflected light from an object and excluding an external light componet from the reflected light

A photosensor group, comprising:

• a plurality of photosensors, each photosensor comprising,
• photoelectric conversion means for converting incident light into a photoelectric current, and
• differential electric quantity generation means for calculating a difference between an electric quantity based on a photoelectric current obtained by said photoelectric conversion means in a first period and an electric quantity based on a photoelectric current obtained by said photoelectric conversion means in a second period, said first period being a period in which a light emitting unit is emitting light, and said second period being a period in which the light emitting unit is not emitting light;
• said differential electric quantity generation means including,
• a first storing electrostatic capacitor in which charges serving as electric quantity corresponding to the first period are stored,
• a second storing electrostatic capacitor in which charges serving as electric quantity corresponding to the second period are stored,
• transfer means for subtracting the charges stored in the second storing electrostatic capacitor from the charges stored in the first storing electrostatic capacitor and transferring resultant charges, and
• a holding electrostatic capacitor in which the charges transferred by said transfer means are stored;
• a wire for one- or two-dimensionally connecting said plurality of photosensors to each other;
• and
• a plurality of scanning switches for selecting said plurality of photosensors, respectively.

A photosensor, comprising:

• photoelectric conversion means for converting incident light into a photoelectric current, and
• differential electric quantity generation means for calculating a difference between an electric quantity based on a photoelectric current obtained by said photoelectric conversion means in a first period and an electric quantity based on a photoelectric current obtained by said photoelectric conversion means in a second period, said first period being a period in which a light emitting unit is emitting light, and said second period being a period in which the light emitting unit is not emitting light;
• wherein, said differential electric quantity generation means comprises:
• storage means for storing electric quantity based on a photoelectric current in the first period;
• reproduction means for reproducing, in the second period, the electric quantity stored in said storage means;
• and
• generation means for performing addition or subtraction of electric quantity based on a photoelectric current in the second period and the electric quantity reproduced by said reproduction means to generate a difference therebetween as electric quantity.

A photo detecting apparatus for detecting reflected light from an object and excluding external light component from the reflected light, comprising:

• a light-emitting unit for emitting light;
• and
• a photo detecting unit, having a plurality of pixels, for detecting light reflected from an object;
• the photo detecting unit, for each pixel, having a photoelectric conversion device for converting the detected light into current;
• a high-pass filter or a bandpass filter for passing a time frequency component, having a frequency higher than a predetermined frequency, of an output from said photoelectric conversion means under a state that said light-emitting unit is emitting light on the object;
• and
• a holding electrostatic capacitor in which the charged having passed through the filter are stored.

A method of sensing distance using a light-emitting unit and a photosensor, said photosensor comprising photoelectric conversion means for converting incident light into a photoelectric current and differential electric quantity generation means for calculating a difference between an electric quantity based on a photoelectric current obtained by said photoelectric conversion means in a first period and an electric quantity based on a photoelectric current obtained by said photoelectric conversion means in a second period, said first period being a period in which the light emitting unit is emitting light, and said second period being a period in which the light emitting unit is not emitting light and wherein the incident light related to the first period is regarded as fixed light and the incident light related to the second period is regarded as reflected light related to light emitted from said light-emitting means, wherein said differential electric quantity generation means comprises, storage means for storing electric quantity based on a photoelectric current in the first period, reproduction means for reproducing, in the second period, the electric quantity stored in said storage means, and generation means for performing addition or subtraction of electric quantity based on a photoelectric current in the second period and the electric quantity reproduced by said reproduction means to generate a difference therebetween as electric quantity, said method comprising:

• emitting light from said light emitting unit;
• detecting light reflecting from an object;
• and
• measuring a time from light emission of said light emitting unit to generation of an electric quantity by said generation means.

In a photosensor group including

• a plurality of photosensors, each photosensor comprising
• photoelectric conversion means for converting incident light into a photoelectric current, and
• differential electric quantity generation means for calculating a difference between an electric quantity based on a photoelectric current obtained by said photoelectric conversion means in a first period and an electric quantity based on a photoelectric current obtained by said photoelectric conversion means in a second period, said first period being a period in which a light emitting unit is emitting light, and said second period being a period in which the light emitting unit is not emitting light, wherein said differential electric quantity generation means comprises.
• storage means for storing electric quantity based on a photoelectric current in the first period,
• reproduction means for reproducing, in the second period, the electric quantity stored in said storage means, and
• generation means for performing addition or subtraction of electric quantity based on a photoelectric current in the second period and the electric quantity reproduced by said reproduction means to generate a difference therebetween as electric quantity;
• a wire for one- or two-dimensionally connecting said plurality of photosensors to each other;
• and
• a plurality of scanning switches for selecting said plurality of photosensors, respectively;
• a method for sensing an image, comprising:
• sensing the incident light with said plurality of photosensors;
• processing the incident light related to the first period as noise light;
• and
• processing the incident light related to the second period as imaging light including the noise light and reflected light from an object to be photographed.