Copying lens for microfilm photography.
A new lens design for precise copying exemplifies the success of the rms error function as a suitable criterion for the design of high resolution lenses. The design, a 145-mm f/4.0, gives 400-line/mm, high contrast,white-light visual resolution throughout a 30-mm flat image when used at 20:1 conjugates. On high resolution plates, a resolution of 320 lines/mm is obtained. The five-glass design has no vignetting of the marginal beams, presents no manufacturing problems, and gave full resolution when first assembled. The prescriptionwas found by the LASL 1972 Lens Design Program.
Faster LASL Lens Design Program.
The following improvements have made the LASL lens design system much faster, though less versatile, and have maintained the calculation accuracy: an increment-vector damping technique optimized by a search procedure, analytic differentiation, simultaneous design on all variables, reliable convergence criteria, vignette control by biased violation errors, bounds for the variables, and an enlarged weighting procedure. The designing system optimizes the sizes and positions of many-ray image spots without consideringthe classical aberrations. As a sample problem the symposium lens has been redesigned.
Automatic Optical Design of Desired Image Distributions using Orthogonal Constraints
The weighting of image errors in an automatic lens design code directly affects the resolution and contrast characteristics of the resulting optical system. The automatic lens design method used employs a least-squares approach. A method of constraining the least-squares solution in an orthogonal vector space which eliminates the need for a damping factor is described. A method of automatically weighting image errors is also described which allows the designer to control the distribution of intensity in the image of a point source. A specific design example is given which illustrates the effect of the image distribution weighting function on the final design.