Dual photocell range finder apparatus

Claim 2

In range finding apparatus for determining the distance of an object relative to a reference plane and including first and second photosensitive devices disposed in a predetermined spaced relation with respect to each other and each having parameters, the magnitude of which respectively vary as a function of the brightness of incident illumination from the object, the combination comprising: a. means coupled to the first and second photosensitive devices for producing a signal having a level which varies in accordance with changes in the magnitudes of the parameters of the first and second photosensitive devices, said signal having a first predetermined magnitude when the parameters of each of the photosensitive devices are at predetermined first relative magnitudes and a second predetermined magnitude when the parameters are at second predetermined relative magnitudes; and b. means responsive to a transition of said signal from the first predetermined magnitude to the second predetermined magnitude for indicating the distance of the object relative to the reference plane.

Claim 3

In range finding apparatus for determining the distance of an object relative to a reference plane and having first and second photosensitive devices disposed in a predetermined spaced relation with respect to each other and each having parameters, the magnitude of which respectively vary as a function of the brightness of incident illumination from the object, the combination comprising: a. means coupled to the first and second photosensitive devices for producing a signal having a level which varies in accordance with changes in the magnitudes of the parameters of the first and second photosensitive devices, said signal having a first predetermined level when the magnitude of the parameters of the photosensitive devices are equal and a second predetermined level when the parameters are at second predetermined relative magnitudes; and b. means responsive to said signal when the level of said signal changes from the first predetermined level to the second predetermined level for determining the distance of the objective relative to the reference plane.

Claim 4

In range finding apparatus for determining the distance of an object relative to a reference plane and having first and second photosensitive devices disposed in a predetermined spaced relation with respect to each other and each having parameters, the magnitude of which respectively vary as a function of the brightness of incident illumination from the object, the combination comprising: a. means coupled to the first and second photosensitive devices for producing a signal having a level which varies in accordance with changes in the magnitudes of the parameters of the first and second photosensitive devices, said signal having a first predetermined level when the magnitude of the parameters of the photosensitive devices are equal and a second predetermined level when the parameters are at second predetermined relative magnitudes; and b. means responsive to said signal when the level of said signal changes from the first predetermined level to the second predetermined level for determining the distance of the objective relative to the reference plane.

Claim 5

In automatic focusing apparatus having means for forming a beam of light, means for projecting and moving the light beam through a range of positions to illuminate at least a portion of an object to be photographed, an objective lens for forming an image of the object in a primary image plane, and focusing means coupled to the objective lens and adapted to move the objective lens along a predetermined path, the combination comprising: a. first and second photosensitive means disposed in a predetermined spaced relation with respect to each other and each adapted to receive light reflected from the object and having parameters, the magnitude of which respectively vary as a function of the brightness of light incident thereon; b. means coupled to said first aNd second photosensitive means for producing a signal having a level which varies in accordance with changes in the magnitudes of the parameters of said first and second photosensitive means, said signal having a predetermined first level when the magnitude of the parameters are equal and a second predetermined level when the magnitude of the parameters are at predetermined relative levels; and c. means coupled to the focusing means and responsive to said signal when said signal changes from the first predetermined level to the second predetermined level to cause the focusing means to dispose the objective lens at a position along the path to focus an image of the object in the primary image plane.

Claim 6

In automatic focusing apparatus having means for forming a beam of light, means for projecting and moving the light beam through a range of positions to illuminate at least a portion of an object to be photographed, an objective lens for forming an image of the object in a primary image plane, and focusing means coupled to the objective lens and adapted to move the objective lens along a predetermined path, the combination comprising: a. first and second photosensitive means disposed in a predetermined spaced relation with respect to each other and each adapted to receive light reflected from the object and having parameters, the magnitude of which respectively vary as a function of the brightness of light incident thereon; b. means coupled to said first aNd second photosensitive means for producing a signal having a level which varies in accordance with changes in the magnitudes of the parameters of said first and second photosensitive means, said signal having a predetermined first level when the magnitude of the parameters are equal and a second predetermined level when the magnitude of the parameters are at predetermined relative levels; and c. means coupled to the focusing means and responsive to said signal when said signal changes from the first predetermined level to the second predetermined level to cause the focusing means to dispose the objective lens at a position along the path to focus an image of the object in the primary image plane.

Claim 7

In automatic focusing apparatus having means for forming a beam of light, means for projecting and moving the beam of light through a range of positions to illuminate at least a portion of an object to be photographed, an objective lens for forming an image of the object in a primary image plane, and focusing means coupled to the objective lens and adapted to move the objective lens along a predetermined path, the combination comprising: a. a first photosensitive device adapted to receive light reflected from the object and having a parameter which varies as a function of the brightness of incident illumination; b. a second photosensitive device adapted to receive light reflected from the object and having a parameter which varies as a function of the brightness of incident illumination; c. means coupled to said first and second photosensitive devices and responsive to variations in the parameters thereof to produce a signal having a level which is relatively positive when said first photosensitive device receives greater brightness of illumination than said second photosensitive device and relatively negative when said second photosensitive device receives greater brightness of illumination than said first photosensitive device and which undergoes a polarity reversal when a condition of equal brightness of incident light on each of said photosensitive devices is passed; and d. means coupled to the focusing means and responsive to said signal after the magnitude of said signal undergoes polarity reversal and changes to a predetermined level measured from its level at polarity reversal to cause the focusing means to dispose the objective lens at a position along the path to focus an image of the object in the primary image plane.

Claim 8

In automatic focusing apparatus having means for forming a beam of light, means for projecting and moving the beam of light through a range of positions to illuminate at least a portion of an object to be photographed, an objective lens for forming an image of the object in a primary image plane, and focusing means coupled to the objective lens and adapted to move the objective lens along a predetermined path, the combination comprising: a. a first photosensitive device adapted to receive light reflected from the object and having a parameter which varies as a function of the brightness of incident illumination; b. a second photosensitive device adapted to receive light reflected from the object and having a parameter which varies as a function of the brightness of incident illumination; c. means coupled to said first and second photosensitive devices and responsive to variations in the parameters thereof to produce a signal having a level which is relatively positive when said first photosensitive device receives greater brightness of illumination than said second photosensitive device and relatively negative when said second photosensitive device receives greater brightness of illumination than said first photosensitive device and which undergoes a polarity reversal when a condition of equal brightness of incident light on each of said photosensitive devices is passed; and d. means coupled to the focusing means and responsive to said signal after the magnitude of said signal undergoes polarity reversal and changes to a predetermined level measured from its level at polarity reversal to cause the focusing means to dispose the objective lens at a position along the path to focus an image of the object in the primary image plane.

Claim 9

In automatic focusing apparatus having means for forming a beam of light, means for projecting and moving the light beam through a range of positions to illuminate at least a portion of an object to be photographed, an objective lens for forming an image of the object in a primary image plane, and focusing means coupled to the objective lens and adapted to move the objective lens along a predetermined path, the combination comprising: a. first and second photosensitive means disposed in a predetermined spaced relation with respect to each other and each adapted to receive light reflected from the object and having parameters, the magnitude of which respectively vary as a function of the brightness of light incident thereon; b. means coupled to said first and second photosensitive means for producing a signal having a level which varies in accordance with changes in the magnitudes of the parameters of said first and second photosensitive means, said signal having a predetermined first level when the magnitude of the parameters are equal and a second predetermined level when the magnitude of the parameters are at predetermined relative levels; c. means coupled to the focusing means for simultaneously moving the objective lens as the beam of light moves through the range of positions; and d. means coupled to the focusing means and responsive to said signal when said signal changes from the first predetermined level to the second predetermined level to cause the focusing means to arrest the objective lenS at a position along the path to focus an image of the object in the primary image plane.

Claim 10

In automatic focusing apparatus having means for forming a beam of light, means for projecting and moving the light beam through a range of positions to illuminate at least a portion of an object to be photographed, an objective lens for forming an image of the object in a primary image plane, and focusing means coupled to the objective lens and adapted to move the objective lens along a predetermined path, the combination comprising: a. first and second photosensitive means disposed in a predetermined spaced relation with respect to each other and each adapted to receive light reflected from the object and having parameters, the magnitude of which respectively vary as a function of the brightness of light incident thereon; b. means coupled to said first and second photosensitive means for producing a signal having a level which varies in accordance with changes in the magnitudes of the parameters of said first and second photosensitive means, said signal having a predetermined first level when the magnitude of the parameters are equal and a second predetermined level when the magnitude of the parameters are at predetermined relative levels; c. means coupled to the focusing means for simultaneously moving the objective lens as the beam of light moves through the range of positions; and d. means coupled to the focusing means and responsive to said signal when said signal changes from the first predetermined level to the second predetermined level to cause the focusing means to arrest the objective lenS at a position along the path to focus an image of the object in the primary image plane.