In Situ alignment system for phase-shifting point-diffraction interferometry
First Claim
Patent Images
1. An optical system defining an optical path that comprises:
- (a) a source of electromagnetic energy in the optical path;
(b) an optical element in the optical path;
(c) at least one of an object mask that is located near the object plane of the optical system or an image mask that is located near the image plane of the optical system wherein the at least one object mask or image mask comprises a patterned screen that defines an array of different sized apertures and a corresponding set of symbols that identify the different sized apertures in said array; and
(d) an intensity detector.
4 Assignments
0 Petitions
Accused Products
Abstract
A device and method to facilitate the gross alignment of patterned object- and image-plane masks in optical systems such as the phase-shifting point diffraction interferometer are provided. When an array of similar pinholes or discreet mask fields is used, confusion can occur over the alignment of the focused beams within the field. Adding to the mask pattern a circumscribed or inscribed set of symbols that are identifiable in situ facilitates the unambiguous gross alignment of the object- and/or image-plane masks. Alternatively, a system of markings can be encoded directly into the window shape to accomplish this same task.
61 Citations
36 Claims
-
1. An optical system defining an optical path that comprises:
-
(a) a source of electromagnetic energy in the optical path; (b) an optical element in the optical path; (c) at least one of an object mask that is located near the object plane of the optical system or an image mask that is located near the image plane of the optical system wherein the at least one object mask or image mask comprises a patterned screen that defines an array of different sized apertures and a corresponding set of symbols that identify the different sized apertures in said array; and (d) an intensity detector. - View Dependent Claims (2, 3)
-
-
4. A phase-shifting point diffraction interferometer system that defines an optical path, said system comprising:
-
(a) a source of electromagnetic energy in the optical path; (b) a beam divider in the optical path for dividing electromagnetic radiation from the source into a reference beam and a test beam; (c) an image mask that is positioned in the image plane of an optical element under test wherein the image mask defines an array of test window and reference beam pinhole pairs and a corresponding set of first symbols that identify the different pairs in said array; and (d) means for detecting an intensity pattern created by the set of first symbols. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
-
-
19. A method of aligning an optical system defining an optical path that includes (i) a source of electromagnetic energy in the optical path, (ii) an optical element in the optical path and (iii) means for detecting an intensity pattern created by the set of symbols that comprises the steps of:
-
(a) providing at least one of an object mask that is located near the object plane of the optical system or an image mask that is located near the image plane of the optical system wherein the at least one object mask or image mask comprises a patterned screen that defines an array of apertures and a corresponding set of symbols that identify at least one of (i) the aperture locations in said array or (ii) the pinhole locations in said array and (b) moving the image mask; and (c) detecting intensity patterns created by the set of symbols. - View Dependent Claims (20, 21)
-
-
22. A method of aligning a phase-shifting point diffraction interferometer defining an optical path that includes (i) a source of electromagnetic energy in the optical path, (ii) a beam divider in the optical path for dividing electromagnetic radiation from the source into a reference beam and a test beam, and (iii) an optical element under test in the optical path, wherein the method comprises the steps of:
-
(a) positioning an image mask in the image plane of the optical system under test wherein the mask defines an array of test window and reference beam pinhole pairs and a corresponding set of first symbols that identify the different pairs in said array; (b) moving the image mask; and (c) detecting intensity patterns created by the set of first symbols. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
-
Specification