Lens meter

An apparatus for measuring at least one component of cylinder of a suspect optical system comprising:

• means for projecting an image of a straight line target along a light path;
• means for holding relative to said light path a suspect optical system including possible components of optical sphere and optical cylinder;
• variable optics in said light path having an optical effect substantially coincident with said suspect optical system, said variable optics including variable spherical optics for varying the spherical correction and variable cylindrical optics for varying cylinder lens power along first intersecting diagonals at substantially equal and opposite angles from the preselected angular alignment of said straight line target;
• said variable optics movable to an optic power of sphere and cylinder equal and opposite to the optic power of said suspect optical system;
• and, means for projecting light passing through said variable optics and said suspect optics to project an image of said straight line target.

A process for measuring the suspect optical system in at least one component of cylinder including the steps of:

• mounting said suspect optical system in a light path;
• projecting light including an image of at least one first straight knife edge of first arbitrary preselected angular alignment without regard to any suspect principal axis of the suspect optical system along said light path;
• providing in said light path variable optics for movement to a power of sphere and cylinder substantially equal and opposite to the components of sphere and cylinder of said suspect optics, said variable optics including variable spherical optics to vary the spherical component of light projected and variable cylindrical optics to vary the cylinder lens power along first intersecting diagonals at substantially equal and opposite angles from preselected angular alignment of said knife edge;
• projecting an image of said knife edge from said collimated light to a knife edge after said light has passed through said variable optics and said suspect optics at least once;
• and, varying said spherical optics and said first cylinder optics to optimize the image of said projected straight knife edge.

A process for measuring the power of a suspect optical system in at least one component of cylinder including the steps of:

• mounting said suspect optical system in a light path;
• projecting light including an image of at least one first straight line target of first arbitrary preselected angular alignment without regard to any suspected principal axis of the suspect optical system along said light path;
• providing in said light path variable optics for movement to a power of sphere and cylinder substantially equal and opposite to the components of sphere and cylinder in said suspect optics, said variable optics including variable spherical optics to vary the spherical component of light projected there through and variable cylindrical optics for varying the cylinder lens power along first intersecting diagonals at substantially equal and opposite angles from the preselected angular alignment of said first straight line target;
• projecting an image of said straight line target from said light passing through said variable optics and said suspect optics;
• and projecting from said light path behind said projected image of said straight line target an image of the suspect optics to a screen;
• and varying said spherical optics and said first cylinder optics to obtain a uniform image of the Focault variety of said suspect optics.

An apparatus for measuring at least one component of cylinder of a suspect optical system comprising:

• means for projecting an image of at least one straight line target along a light path;
• means for holding relative to and in said light path a suspect optical system including possible components of optical sphere and optical cylinder without regard to any suspected principal axis of the suspected optical system along said light path;
• variable optics in said light path for varying the spherical correction and variable astigmatic optics for varying the astigmatic lens power along first intersecting diagonals at substantially equal and opposite angles from the preselected angular alignment of said straight line target, said variable optics movable to an optic power of sphere and astigmatism equal and opposite to the optic power of said suspect optical system;
• means for imaging light passing through said variable optics and said suspect optics to project an image of said straight line target.

An apparatus for measuring at least one component of cylinder of a suspect optical system comprising:

• means for projecting an image of a first knife edge along a light path;
• means for holding relative to said light path a suspect optical system including possible components of optical sphere and optical cylinder;
• variable optics in said light path having an optical effect substantially coincident with said suspect optical system, said variable optics including variable spherical optics for varying the spherical correction and variable cylindrical optics for varying cylinder lens power along first intersecting diagonals at substantially equal and opposite angles from the preselected angular alignment of said straight line target;
• said variable optics movable to an optic power of sphere and cylinder equal and opposite to the optics power of said suspect optical system;
• and, means for projecting an image from the light passing through said variable optics and said suspect optics to a knife edge of said same preselected angular alignment.

An apparatus for measuring at least one component of cylinder of a suspect optical system comprising:

• means for projecting an image of a knife edge along a light path including a light source, a knife edge and optics for projecting light from said source past said knife edge into said optics to emit from said optics light containing an image of said knife edge;
• means for holding relative to said light path a suspect optical system including possible components of optical sphere and optical cylinder;
• variable optics in said light path having an optical effect substantially coincident with said suspect optical system, said variable optics including variable spherical optics for varying the spherical correction and variable cylindrical optics for varying the cylindrical lens power along first intersecting diagonals at substantially equal and opposite angles from the preselected angular alignment of said straight line target;
• said variable optics movable to an optic power of sphere and cylinder equal and opposite to the optical power of said suspect optical system;
• means for projecting light passing through said variable optics and said suspect optics at least once to project an image of said knife edge to a knife edge;
• an imaging screen;
• and, means for imaging to a screen beyond said knife edge an image of said suspect optics.

An apparatus for measuring sphere and cylinder of a suspect optical system comprising:

• means for projecting an image of a first straight line target along a light path;
• means for holding relative to said light path a suspect optical system including possible components of optical sphere and optical cylinder;
• variable optics in said light path having an optical effect substantially coincident with said suspect optical system, said variable optics including variable spherical optics for varying the spherical correction and variable cylindrical optics for varying cylindrical lens power along first intersecting diagonals at substantially equal and opposite angles from the preselected angular alignment of said first straight line target;
• said variable optics movable to an optic power of sphere and cylinder equal and opposite to the optic power of said suspect optical system;
• means for projecting light passing through said variable optics and said suspect optics to project an image of said straight line target at a knife edge;
• means for projecting an image of said suspect optics to a photosensitive surface divided into discrete photosensitive parts over the image of said suspect optical system;
• said discrete parts including outputs indicating differential illumination of said discrete parts of said photosensor;
• means for varying said variable optics including said variable spherical optics and said variable cylinder optics remotely responsive to a differential signal;
• and, means operatively connected between said photosensor segments and said varying means in said variable optics to cause said variable optics to move to create a uniformly illuminated image at said photosensor.

A process for measuring the power of a suspect optical system in prism relative to a preselected point in said suspect optical system including the steps of:

• mounting said suspect optical system in a light path along an axis wherein said point of said suspect optical system is registered to the axis of said light path;
• projecting light including an image of at least one first straight line target of a first arbitrary preselected angular alignment without regard to any suspect principal axis of the suspect optical system along said light path;
• providing variable optics in said light path having variable spherical optics for varying the spherical correction and variable cylindrical optics for varying cylindrical lens power along first intersecting diagonals at substantially equal and opposite angles from the preselected angular alignment of said projected first straight line target;
• providing retroreflecting optics having the property of reflecting and displacing light;
• projecting said light through said suspect optical system and said variable optics to said retroreflecting optics;
• projecting a first image of said straight line target from said reflected and displaced light rebounding from said retrodirective optics to focus the image of said projected straight line target at a preselected location;
• replacing said retrodirecting optics with reflecting means to reflect said light including said image of said first straight line target;
• projecting a second image of said straight line target from said reflected light from said reflecting means;
• and, measuring the displacement of said first and second projected images of said straight line target to determine prism in at least one component at an angle to said straight line.