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2005-10-20 17:19 |
Optical system alignment system and method with high accuracy and simple operati
Optical system alignment system and method with high accuracy and simple operation Nq/,41 xa[<k>r3 Abstract !k)}p_e A system for aligning of optical components includes an interferometer and a first diffractive alignment element. A housing is used for positioning a first optical element being aligned. A detector is used for detecting fringes produced by reflections off surfaces of the first optical element. A grating pattern on the first diffractive alignment element is designed to produce a retro-reflected wavefront or a wavefront transmitted or reflected in a predetermined direction when the first optical element is in alignment. The first diffractive alignment element includes a first region for alignment of the interferometer, a second region for alignment of one surface of the first optical element, and a third region for alignment of another surface of the first optical element. The first, second and third regions can be of any shape such as circular, rectangular, triangular, or the like. 5? &k? v@ -------------------------------------------------------------------------------- rW0# 6 Inventors: Harned, Robert D.; (Redding, CT) ; Harned, Nora-Jean; (Redding, CT) CS)&A4`8 Correspondence Name and Address: STERNE, KESSLER, GOLDSTEIN & FOX PLLC G|Yw
a= 1100 NEW YORK AVENUE, N.W. L= O,OS+ WASHINGTON &cV$8*2b^ DC Oz#$x 20005 dE7 kd=.o US fIu5d6;' N6S0(% 7hZCh,O Assignee Name and Adress: ASML Holding N.V. ~}q"M[{ Veldhoven _r0oOp E NL ZSuUmCm d kHcG&) >9'G>~P~I= Serial No.: 938954 };o6|e:2E Series Code: 10 bHH{bv~Z Filed: September 13, 2004 CkE@Ll3Z ,%w_E[2 U.S. Current Class: 356/508 ^>gRK*, U.S. Class at Publication: 356/508 'S@% Intern'l Class: G01B 009/02 FbO-K- LY'_U0y4 -------------------------------------------------------------------------------- z9}rT<hy d/!sHr69 Claims gdT3,8`#[ Ir|Q2$W2^c -------------------------------------------------------------------------------- D|/Azy.[ "aHY]E{ What is claimed is: \:mx Ri 1. A system for aligning of optical components, comprising: an interferometer; a reference optic; a first diffractive alignment element having a grating pattern thereon; a housing that positions a first optical element being aligned; and a detector that detects fringes produced by reflections off surfaces of the first optical element, wherein the grating pattern produces diffracted wavefronts that align the first diffractive alignment element to the reference optic and that align the first optical element. 5V!L~# 3Bee6N> 2. The system of claim 1, wherein the first diffractive alignment element comprises: a first region that aligns the interferometer; a second region that aligns one surface of the first optical element; and a third region that aligns another surface of the first optical element. }jBr[S5 JryDbGc8 3. The system of claim 2, wherein the first, second and third regions are generally circular. 7Te`#" M8X*fYn 4. The system of claim 3, wherein the circular regions are non-concentric. VQ5T$,& [wG?&l$.KB 5. The system of claim 3, wherein the circular regions are decentered relative to an optical axis of the system. t_6sDr'. tuo'4%]i 6. The system of claim 1, wherein the first diffractive alignment element is capable of being replaced by a second diffractive optical alignment that aligns a second optical component. !/znovoD [7q~rcf,Z 7. The system of claim 1, wherein the first diffractive alignment element comprises a plurality of regions, each region used for alignment of a different surface of a plurality of optical components being aligned within the housing. 3P 3x^NI Vh$~]>t:f 8. The system of claim 7, wherein at least one of the regions is used for alignment of an aspheric surface. ?`V%[~4_I EgM.wQHR] 9. The system of claim 1, wherein the plurality of regions correspond to a plurality of surfaces of a multi-element lens being aligned. 7m_Jb5 d!7cIYVZ 10. The system of claim 1, wherein the first optical element is a reflective element. rQg7r>%Q yS p]+ 11. The system of claim 1, wherein the first optical element is a refractive element. 3.U5Each- Rcs7 'q5 12. The system of claim 1, wherein the first optical element is an off-axis optical element. ';us;xR# >DVjO9Kf 13. The system of claim 12, further comprising a second diffractive alignment optical element that produces interference fringes in the interferometer using a reflection off the off-axis optical element. 3GUO ftq&<8 14. The system of claim 13, wherein the second diffractive alignment optical element is a transmissive grating. !^cQPX2< gm~Ka%O|F 15. The system of claim 13, wherein the second diffractive alignment optical element is a reflective grating. $J"}7+ I&Q.MItW 16. The system of claim 1, wherein the first optical component has a spherical surface. I$xfCu oNY;z-QK 17. The system of claim 1, wherein the first optical component has an aspheric surface. vT"T*FKh: &MsnQP 18. The system of claim 1, further comprising any one of a transmission flat, a transmission sphere, or a lens between the interferometer and the first diffractive alignment element. 2#~5[PtP^ -------------------------------------------------------------------------------- kKAK;JQ <^6|ZgR Description zRN_`U L3iYZ>] -------------------------------------------------------------------------------- Lo
_5r T" Bi/=cI +Rn]6}5m\ CROSS-REFERENCE TO RELATED APPLICATIONS c7X5sMM, %$|=_K)Ks [0001] This application claims priority to U.S. Provisional Application No. 60/554,420, filed Mar. 19, 2004, titled "OPTICAL SYSTEM ALIGNMENT SYSTEM AND METHOD WITH HIGH ACCURACY AND SIMPLE OPERATION," which is incorporated herein by reference in its entirety. A+w51Q (|L0s) BACKGROUND OF THE INVENTION |_/q0#" [R*UPa [0002] 1. Field of the Invention RX}6H<5R hE0
p>R8 [0003] The present invention relates to alignment of optical components, and more particularly, to alignment of reflective and refractive optical components in high precision optical systems. [}q6bXM* \M(0@#-$C [0004] 2. Related Art ~K]5`(KV &+;z`A'|8 [0005] Most multiple lens assemblies are currently aligned using one (or more) of the following methods: +F$c_
\> hZf0q 2 [0006] (a) Mechanical indicators are used for either (or both) centering the outside diameter and minimizing the apparent wedge between lens surfaces relative to the lens cell; <o,]f E[ yM>:,T S [0007] (b) Alignment telescopes can be used for aligning centers of curvatures of the lens elements to a common optical axis; URS6
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8CP [0008] (c) Fabricating the lens elements and the lens cell to very tight optical and mechanical tolerances, so that a "slip fit" of the elements in the cell results in an aligned system; and 1^^<6e `K37&b | |