Moiré deflectometer including non-mechanical, transparent, spatial light modulators for demonstrating two-axis rulings
AssigneeLSA, Inc.
InventorsDale R. Tyczka, John G. Lehman, Jr., Alvin B. Cabato, Daniel Stern
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Abstract
A Moiré deflectometer includes at least three non-mechanical, transparent, spatial light modulators for demonstrating two sets of patterns on two parallel planes on two of the modulators thereby creating a Moiré fringe pattern and a method for using the same. More particularly, each of the spatial light modulators may be a liquid crystal display, an electrochromic device, a micromirror array, a microlouvre array, an electro-optic device, or a holographic device.
Claims21
A resolution-variable Moiré deflectometer comprising:
- a light source;
- a beamsplitter;
- an image recorder aligned with the a beamsplitter to define an optical axis of said deflectometer;
- at least three non-mechanical, transparent, spatial light modulators placed along said optical axis of said deflectometer with gaps in-between,
- distance varying means which selectively turns on at least two of said spatial light modulators and turns off at least one of said spatial light modulators to demonstrate each of two sets of parallel lines on one corresponding plane therein at a variable distance so as to create a Moiré fringe pattern.
A method for measuring a surface contour or a phase-shifting character of an object, comprising:
- providing at least three non-mechanical, transparent, spatial light modulators placed along an optical axis;
- selectively demonstrating two sets of parallel lines in two of said spatial light modulators respectively on one corresponding plane therein thereby varying a distance between the planes demonstrating said two sets of parallel lines, said planes are parallel to each other;
- projecting light onto the object;
- guiding a reflected light reflected by a surface of the object or a mirror behind the object toward the planes;
- detecting a Moiré pattern behind said spatial light modulators;
- and
- comparing a pattern demonstrated on said spatial light modulators with the Moiré pattern to determine the surface contour or the phase-shifting character of the object.
Dependencies are inferred from the claim text.