Photoelectric lens bench and method for testing optical systems

Claim 2

In a method for testing the response of an optical system, which includes the steps of: positioning a spatial-frequency target at a target plane; imaging the target by the optical system under test at an image plane angled with respect to the target plane such that the amplitude of the spatial-frequency target image varies along the direction of increasing distance between the target plane and the image plane; and forming a signal representing the actual spatial frequency of the target; the improvement comprising the step of correcting the signal representing the actual spatial frequency of the target to compensate for perspective error resulting from the angle between the target plane and the image plane.

Claim 3

In a method of testing the response of an optical system at an infinite conjugate, which includes the steps of: positioning a spatial-frequency target at a location displaced from the optical axis of the optical system under test; and forming a signal indicative of the actual spatial frequency of the target; the improvement comprising the step of correcting the signal representing the actual spatial frequency of the target to compensate for magnification error resulting from such displacement of the target from the optical axis of the optical system.

Claim 4

In a method of testing the response of an optical system at an infinite conjugate, which includes the steps of: positioning a spatial-frequency target at a location displaced from the optical axis of the optical system under test; and forming a signal indicative of the actual spatial frequency of the target; the improvement comprising the step of correcting the signal representing the actual spatial frequency of the target to compensate for magnification error resulting from such displacement of the target from the optical axis of the optical system.

Claim 5

In a method of testing the response of an optical component which includes the steps of: positioning a spatial-frequency target at a target Plane at an infinite conjugate with respect to the optical component; imaging the target by the optical component under test at an image plane angled with respect to the target plane such that the amplitudes of the target image vary along the direction of increasing distance between the object plane and the image plane; and generating a response representing the actual spatial frequency of the target; the improvement comprising the steps of correcting the response representing the actual spatial frequency of the target to compensate for perspective error resulting from the angle between the target plane and the image plane, and correcting the response representing the actual spatial frequency of the target to compensate for magnification error resulting from the displacement of the target from the optical axis of the optical components.

Claim 6

In a method of testing the response of an optical component which includes the steps of: positioning a spatial-frequency target at a target Plane at an infinite conjugate with respect to the optical component; imaging the target by the optical component under test at an image plane angled with respect to the target plane such that the amplitudes of the target image vary along the direction of increasing distance between the object plane and the image plane; and generating a response representing the actual spatial frequency of the target; the improvement comprising the steps of correcting the response representing the actual spatial frequency of the target to compensate for perspective error resulting from the angle between the target plane and the image plane, and correcting the response representing the actual spatial frequency of the target to compensate for magnification error resulting from the displacement of the target from the optical axis of the optical components.

Claim 13

An optical bench for testing lens systems having an optical axis, said bench comPrising: means including one or more lines target discs for forming a test object of determinable and variable spatial frequency; means for generating a signal representing the actual spatial frequency of said test object; means for supporting a lens system to be tested; means for adjusting the position of the test object relative to the lens system for locating the test object off the optical axis of the lens system; and at least one function generator operatively connected to said signal generating means for altering said signal to correct for changes in the spatial frequency of the test object as imaged by the lens system which are due to the test object being located off the optical axis of the lens system.

Claim 14

An optical bench for testing lens systems having an optical axis, said bench comPrising: means including one or more lines target discs for forming a test object of determinable and variable spatial frequency; means for generating a signal representing the actual spatial frequency of said test object; means for supporting a lens system to be tested; means for adjusting the position of the test object relative to the lens system for locating the test object off the optical axis of the lens system; and at least one function generator operatively connected to said signal generating means for altering said signal to correct for changes in the spatial frequency of the test object as imaged by the lens system which are due to the test object being located off the optical axis of the lens system.

Claim 15

An optical bench for testing lens systems having an optical axis, in accordance with claim 7, wherein said function generator is a cosine potentiometer.

Claim 16

An optical bench for testing lens systems having an optical axis, comprising: means including at least one lined target for forming a test object of determinable and variable spatial frequency in an object plane; means for establishing a signal representing the actual spatial frequency of said test object; holding means for locating a lens system to be tested; means defining an image plane at which the lens system forms an image of the test object; receiving means for sensing an image of the test object at the image plane; means for adjusting the test object with respect to the test image to establish an angle between the object plane and the image plane; and at least one function generator operatively connected to said signal generating means for altering said signal to compensate for s changes in the spatial frequency of the test image which are due to the angle between the object plane and the image plane.

Claim 17

An optical bench for testing lens systems having an optical axis, comprising: means including at least one lined target for forming a test object of determinable and variable spatial frequency in an object plane; means for establishing a signal representing the actual spatial frequency of said test object; holding means for locating a lens system to be tested; means defining an image plane at which the lens system forms an image of the test object; receiving means for sensing an image of the test object at the image plane; means for adjusting the test object with respect to the test image to establish an angle between the object plane and the image plane; and at least one function generator operatively connected to said signal generating means for altering said signal to compensate for s changes in the spatial frequency of the test image which are due to the angle between the object plane and the image plane.

Claim 18

In an optical bench for testing optical systems having an optical axis and a principal plane, and including a lined test object of variable spatial frequency, electrical means for generating a signal voltage proportional to the variable spatial frequency, means for orienting the test object off the optical axis of an optical system under test and in a plane oriented at an angle to the principal plane of the optical system, the improvement comprising at least one potentiometer means operatively associated with the electrical signal generating means for altering the signal voltage by a cosine function to correct for perspective error resulting from the angle between the object plane and the principal plane and magnification error resulting from the off-axis position of the test object with respect to the optical axis of the optical system.

Claim 19

In an optical bench for testing optical systems having an optical axis and a principal plane, and including a lined test object of variable spatial frequency, electrical means for generating a signal voltage proportional to the variable spatial frequency, means for orienting the test object off the optical axis of an optical system under test and in a plane oriented at an angle to the principal plane of the optical system, the improvement comprising at least one potentiometer means operatively associated with the electrical signal generating means for altering the signal voltage by a cosine function to correct for perspective error resulting from the angle between the object plane and the principal plane and magnification error resulting from the off-axis position of the test object with respect to the optical axis of the optical system.

Claim 20

An optical bench, for testing a lens system having an optical axis and a principal plane, comprising: at least one lined screen defining a plane and for forming a test object of variable spatial frequency; means for developing a first electrical output indicative of the spatial frequency of the test object; means for supporting the lens system with the optical axis of the lens system displaced at an angle from the test object and with the principal plane of the lens system oriented at an angle with respect to the plane of said screen, said support means being located with respect to the test object such that the lens system supported thereby will form a test image of the test object; a photoelectric receiver for sensing a test image formed by the lens system in an image plane parallel to the principal plane of the lens system and for developing a second electrical output indicative of the test image in said image plane; a first cosine potentiometer electrically connected to said means for developing said first electrical output and having a resistance element and a contact movable relative to said element to develop an output potential related to a function of the cosine of the angle by which the principal plane of the lens system is oriented with respect to the plane oF said screen; a second cosine potentiometer electrically connected to said first potentiometer, and having a second resistance element and a contact movable relative to said element to develop an output potential related to a function of the cosine of the angular amount by which the optical axis of the lens system is displaced from the object; first switch means for electrically connecting said first potentiometer to said means for developing said first electrical output to correct for perspective error resulting from the angle by which the principal plane of the lens system is oriented with respect to the plane of said screen; and second switch means for electrically connecting said second potentiometer to said first potentiometer to correct for magnification error resulting from the angular amount by which the optical axis of the lens system is displaced from the object.

Claim 21

An optical bench, for testing a lens system having an optical axis and a principal plane, comprising: at least one lined screen defining a plane and for forming a test object of variable spatial frequency; means for developing a first electrical output indicative of the spatial frequency of the test object; means for supporting the lens system with the optical axis of the lens system displaced at an angle from the test object and with the principal plane of the lens system oriented at an angle with respect to the plane of said screen, said support means being located with respect to the test object such that the lens system supported thereby will form a test image of the test object; a photoelectric receiver for sensing a test image formed by the lens system in an image plane parallel to the principal plane of the lens system and for developing a second electrical output indicative of the test image in said image plane; a first cosine potentiometer electrically connected to said means for developing said first electrical output and having a resistance element and a contact movable relative to said element to develop an output potential related to a function of the cosine of the angle by which the principal plane of the lens system is oriented with respect to the plane oF said screen; a second cosine potentiometer electrically connected to said first potentiometer, and having a second resistance element and a contact movable relative to said element to develop an output potential related to a function of the cosine of the angular amount by which the optical axis of the lens system is displaced from the object; first switch means for electrically connecting said first potentiometer to said means for developing said first electrical output to correct for perspective error resulting from the angle by which the principal plane of the lens system is oriented with respect to the plane of said screen; and second switch means for electrically connecting said second potentiometer to said first potentiometer to correct for magnification error resulting from the angular amount by which the optical axis of the lens system is displaced from the object.