Optics: measuring and testing – Lens or reflective image former testing – Focal length measuring
Patent
1976-03-26
1978-01-24
Clark, Conrad J.
Optics: measuring and testing
Lens or reflective image former testing
Focal length measuring
356127, G01D 900
Patent
active
040701158
ABSTRACT:
A lens meter is disclosed in which continuously variable spherical and astigmatic corrective optics are manipulated to measure the prescription of a suspect optical system. A target including a straight line is focused for maximum clarity, the target being arbitrarily aligned without respect to the axis of the suspect optical system. Continuously variable spherical and first astigmatic optics are juxtaposed to the suspect optics and the image of the target projected through both the suspect optics and the continuously variable optics. Spherical and first astigmatic corrections along at least one axis diagonal to the line target is made until maximum sharpness of a projected image of the line results. A first component of astigmatic correction results. A second target, again consisting of a straight line, is introduced; this target is angularly inclined with respect to the first target preferably at 45.degree.. Spherical adjustment is made together with a diagonally aligned second astigmatic correction along at least one axis diagonal to the second line target until maximum sharpness of the projected image of the line results. A second component of astigmatic correction and final spherical correction results. Provision is made for remote manipulation of the continuously variable optics to determine prescription automatically.
REFERENCES:
patent: 3822932 (1974-07-01), Humphrey
patent: 3832066 (1974-08-01), Cornsweet
patent: 3841760 (1974-10-01), Guyton
patent: 3947097 (1976-03-01), Humphrey
Clark Conrad J.
Humphrey Instruments Inc.
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