The effectiveness of global optimizers for non-zoomed lenses has been steadily improving, but until recently their application to zoom lens design has been less successful. Although some methods have been able to make minor improvements to initial design forms, the algorithms have not consistently discovered new solutions with different group power distributions in a single run. In many cases, the difficulty appears related to how effective focal length (EFL) is controlled across zoom positions. Improvements made to the Global SynthesisTM (GS) algorithm in Code VTM, together with a revised strategy for controlling the EFL via weighted constraints, have significantly improved the ability of GS to discover distinct zoom lens solutions, including those with different group powers. We offer a plausible explanation for the success of these changes, and we discuss an example zoom lens design problem based on a 2-group, 7-element patent design.
Recent progress in global optimization has raised new interest in the application of global methods to lens design. This paper has several goals. We describe the attributes of a new global algorithm, Global SynthesisTM (GS), and we distinguish it from previously reported methods on the basis of efficiency and the ability to handle many (i.e., > 50) variables and comparable numbers of active, nonlinear, equality, and inequality constraints. Many experienced designers doubt, often with good reason, that multiple minima exist for practical problems, so we present meaningful examples showing additional minima often do exist. These test cases, some with known optimal solutions, can be used to study and benchmark the performance of different methods, and we describe recent results with GS on these test problems. We discuss what is meant by `success' in global optimization, and point out the practical limits of current methods. Finally, we discuss what impact global optimization may have on optical design as it becomes a mainstream tool of designers.
Recent progress in global optimization has raised new interest in the application of global methods to lens design. This paper has several goals. We describe the attributes of a new global algorithm, Global Synthesis (OS), and we distinguish it from previously reported methods on the basis of efficiency and the ability to handle many (i.e., >50) variables and comparable numbers of active, nonlinear, equality and inequality constraints. Many experienced designers doubt, often with good reason, that mu1ple minima exist for practical problems, so we present meaningful examples showing additional minima often do exist. These test cases, some with known optimal solutions, can be used to study and benchmark the performance of different methods, and we describe recent results with OS on these test problems. We discuss what is meant by "success" in global optimization, and point out the practical limits of current methods. Finally, we discuss what impact global optimization may have on optical design as it becomes a mainstream tool of designers.
This paper is part of a session that is aimed at briefly describing some of today''s optical design software packages with emphasis on the program''s philosophy and technology. CODE V is the ongoing result of a development process that began in the 1960''s it is now the result of many people''s efforts. This paper summarizes the roots of the program some of its history dominant philosophies and technologies that have contributed to its usefulness and some that drive its continued development. ROOTS OF CODE V Conceived in the early 60''s This was at a time when there was skepticism that " automatic design" could design lenses equal or better than " hand" methods. The concepts underlying CODE V and its predecessors were based on ten years of experience and exposure to the problems of a group of lens designers in a design-for-manufacture environment. The basic challenge was to show that lens design could be done better easier and faster by high quality computer-assisted design tools. The earliest development was for our own use as an engineering services organization -an in-house tool for custom design. As a tool it had to make us efficient in providing lens design and engineering services as a self-sustaining business. PHILOSOPHY OF OVTIM!ZATION IN CODE V Error function formation Based on experience as a designer we felt very strongly that there should be a clear separation of
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