Distance determining and automatic focusing apparatus

Automatic focusing apparatus, comprising

• primary optical means arranged for producing a primary image of an object on an image plane and capable of adjustment into that position in which said image is in best focus on said plane for the existing object distance,
• a plurality of radiation responsive elements divided into two similar detector arrays, each of said elements being arranged to provide an electrical signal representative of the intensity of radiation impinging thereon,
• first auxiliary optical means defining a first optical path for radiation from the object and for forming a first detection image thereof on solely one of said arrays,
• second auxiliary optical means defining a second optical path for radiation from the object and for forming a second detection image thereof on solely the other of said arrays, the positions and radiation distributions of said detection images on the corresponding arrays changing with changes in the relative positions of said auxiliary means and said arrays, and with changes in the object distance, there being for each such distance a one of the last-mentioned positions at which there is best correspondence of said distributions on said arrays.
• scanning means for relatively moving at least a portion of at least one of said auxiliary means and the corresponding one of said arrays progressively through a predetermined range of relative positions during each of continuously repeated time periods, said range including said one position at which there is said best correspondence of said distributions on said arrays for the existing object distance,
• signal processing means connected to said elements for comparing the signal from each of said elements of one of said arrays with the signal from the positionally corresponding one of said elements of the other of said arrays, and for summing the results of such comparisons to provide an output signal which exhibits a predetermined effect when said best correspondence of said distributions on said arrays is obtained during each of said periods, and
• responsive means coupled to said signal processing means, said scanning means, and said primary optical means, and responsive to said effect and to said relative moving of said auxiliary means and said arrays to effectively ascertain at which of said relative positions in said range said effect is produced during each of said periods, and to adjust said primary optical means into a position corresponding to said ascertained position, this adjusted position of said primary optical means being that in which said primary image is in best focus on said plane.

Apparatus for providing a measure of the distance between the apparatus and an object, comprising

• a plurality of radiation responsive elements divided into two similar detector arrays, each of said elements being arranged to provide an electrical signal representative of the intensity of radiation impinging thereon,
• first auxiliary optical means defining a first optical path for radiation from the object and for forming a first detection image thereof on solely one of said arrays,
• second auxiliary optical means defining a second optical path for radiation form the object and for forming a second detection image thereof on solely the other of said arrays, the positions and radiation distributions of said detection images on the corresponding arrays changing with changes in the relative positions of said auxiliary means and said arrays, and with changes in the object distance, there being for each such distance a one of the last-mentioned positions at which there is best correspondence of said distributions on said arrays,
• scanning means for relatively moving at least a portion of at least one of said auxiliary means and the corresponding one of said arrays progressively through a predetermined range of relative positions during a time period, said range including said one position at which there is said best correspondence of said distributions on said arrays for the existing object distance,
• signal processing means connected to said elements for comparing the signal from each of said elements of one of said arrays with the signal from the positionally corresponding one of said elements of the other of said arrays, and for summing the results of such comparisons to provide an output signal which exhibits a predetermined effect when said best correspondence of said distributions on said arrays is obtained during said period, and
• responsive means including first means coupled to said signal processing means and said scanning means and responsive to said effect and to said relative movement of said auxiliary means and said arrays to effectively ascertain at which of said relative positions in said range said effect is produced during said period, and including a movable member and servo means coupled to said member and to said first means to adjust said member into a position corresponding to said ascertained position, the adjusted position of said member being a measure of said object distance.

Apparatus for automatically focusing the image of an object, comprising

• a plurality of radiation responsive elements divided into two similar detector arrays, each of said elements being arranged to provide an electrical signal representative of the intensity of radiation impinging thereon,
• first auxiliary optical means defining a first optical path for radiation from the object and for forming a first detection image thereof on solely one of said arrays,
• second auxiliary optical means defining a second optical path for radiation from the object and for forming a second detection image thereof on solely the other of said arrays, the positions and radiation distributions of said detection images on the corresponding arrays changing with changes in the relative positions of said auxiliary means and said arrays, and with changes in the object distance, there being for each such distance a one of the last-mentioned positions at which there is best correspondence of said distributions on said arrays,
• scanning means for relatively moving at least a portion of at least one of said auxiliary means and the corresponding one of said arrays progressively through a predetermined range of relative positions during a time period, said range including said one position at which there is said best correspondence of said distribution on said arrays for the existing object distance,
• signal processing means connected to said elements for comparing the signal from each of said elements of one of said arrays with the signal from the positionally corresponding one of said elements of the other of said arrays, and for summing the results of such comparisons to provide an output signal which exhibits a predetermined effect when said best correspondence of said distributions on said arrays is obtained during said period,
• primary optical means arranged for producing a primary image of the object on an image plane and capable of adjustment into any of a plurality of positions, said primary image being in best focus on said plane when the position of said primary optical means corresponds to the one of said relative positions in said range at which said effect is produced during said period, and
• responsive means including first means coupled to said signal processing means and said scanning means and responsive to said effect and to said relative movement of said auxiliary means and said arrays to effectively ascertain at which of said relative positions in said range said effect is produced during said period, and including second means coupled to said primary optical means to effectively ascertain the instantaneous position thereof, to compare said two ascertained positions, and to adjust said primary optical means as necessary to make said ascertained positions correspond.