Optical Design Compensation from Engineering to Production Manufacturing C. Theodore Tienvieri, Tim Rich Corning Tropel Corporation 60 O’Connor Rd Fairport, NY 14450 [email protected], [email protected] Abstract: This paper will discuss transitioning a precision optical system from engineering to a manufacturing process stream. OCIS codes: (220.3620) Lens design; (220.3630) Lenses; (220.4610) Optical fabrication 1. Introduction Many optical systems for precision applications such as optical inspection, micro-lithography, DVD mastering, and projection printing require significant optical engineering involvement to support the manufacturing team in fabricating these systems. Performance demands placed upon lenses used in these industries often dictate diffraction limited wavefront quality, minimal image distortion, and resolution of very small features. Achieving the necessary “as-built” performance requirements for the lens assembly can mean optical designer involvement to select and compensate manufactured parts, prior to release to the component assembly team. This level of detailed engineering involvement is suitable for proto-type quantities but can constrain the manufacturing stream when the system transitions to sizeable production quantities. Support in the manufacture of volume assemblies can require a dedicated team of optical design engineers to manage the day to day project needs of lens selection and compensation in order to keep pace with the program’s delivery rate. A second option to manage the engineering duties of precision optical systems is to develop a manufacturing stream which enables transferring and transitioning designer project support to the assembly and fabrication teams. 2. Manufacturing Philosophy and Key Components In producing many state of the art optical systems, the manufacturing strategy hinges around a philosophy whereby each fabricated objective is first modeled and simulated in optical design software prior to committing to assembling the components (figure 1). A group of lens elements will first be custom selected from the population of manufactured parts to minimize aberration build up. The component’s measured fabrication properties (radius, thickness, index,…) will be modeled in design code and further performance gains achieved by optimizing with pre- determined air spaces. SELECTION of MANUFACTURED SYSTEM EVALUATE RELEASE to COMPONENTS COMPENSATION PERFORMANCE MANUFACTURING Fig. 1 Manufacturing Philosophy International Optical Design Conference 2006, edited by G. Groot Gregory, Joseph M. Howard, R. John Koshel, SPIE Vol. 6342, 63422S, © 2006 SPIE-OSA · 0277-786X/06/$15 · doi: 10.1117/12.692220 SPIE-OSA/ Vol. 6342 63422S-1 Downloaded From: http://spiedigitallibrary.org/ on 05/28/2013 Terms of Use: http://spiedl.org/terms Mechanical parts will be adjusted accordingly to achieve desired lens spacings. This manufacturing concept allows for looser optical fabrication tolerances as opposed to building a static objective. Fine tuning and computer simulation of each optical assembly has often been the task of the optical designer. This methodology is fine for small quantity production, but how might it be applied to producing optical systems with sizeable volume? A manufacturing strategy has been developed to create a Volume Manufacturing Compensation Platform (VMCP) for quantity production of high performance optical systems. A suitable software platform and suite of compensation tools has been implemented to integrate optical design support duties to a volume manufacturing stream (VMS). The key components of the platform (figure 2) consist of an integrated computer network accessible to design and manufacturing, electronic fabrication records stored in a Lens Manufacturing Database (LMD)[1], optical design analysis/compensation software, and lens assembly report specific to each manufactured lens unit. This infrastructure lends itself to automating the design compensation process, which allows for incorporation into a production VMS. Lens Manufacturing Database (LMD) Optical Design Code OPTICAL DESIGN Build Solution Compensation Assembly Mechanical MANUFACTURING Report Fig. 2. Volume Manufacturing Compensation Platform 3. Project Requirements for VMCP There are basic requirements the project must fulfill to be integrated into the VMCP. The volume must be large enough to justify spending time and effort to develop the underlying software code to manage the data collection, design optimization, solution tracking, and reporting. In many optical projects if more than one to two dozen lenses are to be manufactured, the investment effort will be re-couped. The design compensation strategy must be robust, well understood, and characterized. This means the system compensation algorithm does not need to be fine tuned or adjusted on a set by set basis to yield an acceptable solution. The tolerance budgets need to be carefully assigned to different manufacturing parameters such as optics, mechanics, assembly, and test. This aids in establishing acceptance threshold criteria to judge if a lens solution can be released to assembly for building. 4. VMCP and Operation The VMCP is developed to be compatible with a variety of different lens systems, complexities, compensation paths, and manufacturing requirements. Each lens system has its own unique built in performance metrics and compensation processes which need to be adhered to. These parameters are decided jointly between the lens design SPIE-OSA/ Vol. 6342 63422S-2 Downloaded From: http://spiedigitallibrary.org/ on 05/28/2013 Terms of Use: http://spiedl.org/terms and manufacturing teams. Necessary process information is committed to work procedures and flow diagrams. An optical designer generally oversees the project’s development and integration into the VMCP. The design quality metrics computed in the software consist of parameters utilized to judge adherence to design tolerances, specification, and any merits which may be quantified in the test laboratory. For example, theoretical performance merits evaluated could include wavefront RMS and spherical aberration, which could then be verified by interferometry in the test lab. Running design compensations with the VMCP is relatively simple. The optical elements to be assembled are selected from the Lens Manufacturing Database. An implemented LMD facilitates this process by a simple point and click user interface (figure 3). Components are grouped by their project designated set number or available stock elements. Each lens component is compared to manufacturing specifications and the impact to performance computed. This information is utilized to quickly determine the performance change due to a particular component being placed into a lens assembly. The lens set’s specific manufactured data (radius, ct, index,…) can easily be exported to optical design code for optimization and analysis. E!SdIImfllthI LSy%ISIOS 063Tiger Objective System & Set # St 1093 ..:J Designation DST I L9 30.1167 30.0000 0.116756.4%0.00 0.00 0.00 0.707 -0.006 -0.0096-0.0225-0.02460.00660.0014 2 FIB 16.4064 16.3500 0.056477.9%0.00 -0.03 -0.05 1.063 -0.017 0.1606 -0.0464-0.01330.0233-0.0102 3 72 9.0600 9.0000 0.060060.0%0.00 -0.02 -0.05 0.969 -0.0110.1379 -0.0156-0.01530.00470.0075 4 194-04 25.009625.00000.0096l9.2T 0.00 -0.01 -0.01 0.301 -0.025 0.0429 -0.0051-0.0069-0.0035-0.0005 5 64-04 30.5616 30.5500 0.031663.6%0.01 CURRENT-0.04 -0.03 1.141 SET-0.097 0.09360.01650.0050-0.0036-0.0064 6 L4-04 22.564922.50000.064966.5%0.00 0.00 0.04 -0.142 0.002 0.0069 -0.0079-0.00740.00660.0026 Export to 719426.506726.50000.00676.9T 0.00 DESIGNATION0.00 0.00 0.072 -0.002 0.0514 -0.0100-0.02160.0074-0.0019 6 15.756015.72000.0360 0.00 0.01 -0.01 0.013 -0.001 -0.01000.0126 -0.01440.00160.0039 36.0% Design Code 9 UI1910 15.0014 15.0000 0.0014 1.4% 0.00 0.00 0.00 0.000 -0.001 0.05790.00330.00450.00ll -0.0015 10 M4-046k5.622955.56500.037937.9% 5] 0.0 -0.1 -0.1 4.144 -0.1560.5520-0.0753 -0.09420.0464-0.0051 Stock – Set ZSF RdiidCT DCdS Controls J!11± 6 STOCK EI ID CT NCTDI%CT%©1T©I SF6 CMA 650 650 1966 6FL 29 216 225 236 237 2 66 16.345316.3500 -0.0047 -6.3% 0.00 0.00 0.00 -0.066 0.00' 0.0030 -0.04540.0092 -0. 00620.0039 2 610 16.354016.3500 0.0040 5.3% 0.00 0.00 0.00 0.073 -0.001 0.1261 -0.0567 -0.00670.0151-0.0030 V 2 35 16.355316.3500 0.0053 7.1% 0.00 0.00 0.00 0.096 -0.002 -0.0065-0.036' -T.01330.00400.0107— 2 67 16.355616.3500 0.0056 7.7% 0.00 0.00 -0.010.106 -0.002 -0.0067-0.0270 -T.02110.01900.0043 2 36 16.362616.3500 0.0126 17.1%0.00 -0.01 -0.010.233 I -0.004 0.0406 -T.03300.01330.0201I-o.ooss 2 34 16.365616.3500 0.0156 20.6%0.00 -0.01 -0.010.264 -0.005 0.0196 -0.0027 1-0.0299 1-0.00030.0040 2 12 16.369516.3500 0.0195 26.0% STOCK0.00 -0.01 -0.020.355 ELEMENTS-0.006 0.0194 -T.05640.01360.0117-0.0064 2 HI 16.374916.3500 0.0249 33.2%0.00 -0.01 -0.020.453 -0.007 0.0526 -0.0176 -0.01690.0246-0.0076 3 ITS 6.93069.0000 -0.0692 -92.3%0.00 0.03 0.06 -1.140 0.012 0.14560.0110-0.01660.0299-0.0333 3 lIT 6.96469.0000 -0.0352 -46.9%0.00 0.0' 0.03 -0.560 0.006 0.1046 -0.0027 -T.03260.01460.0079 S F:9 6H1Srnhl -57(04-Tc%Tr•1Tr•1T70 -0707 57(0 0147007074-57607-Tr6TSTfllSO Fig.