1 November 1991 Optical glass selection using computerized data base
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The selection of optical glasses by the lens designer should, by all rights, be a scientifically sound and straightforward task. Unfortunately, this is not the case. The designer is faced with a myriad of potential glass types to use, and in reality, the task is both a science as well as an art. Part of the problem lies in the fact that while the basic optical parameters, namely the refractive index and the Abbe number or V-number are readily accessible in the catalogue or on the standard glass map, many other attributes regarding the specific glasses such as physical properties, resistance to stain or bubbles, and many other parameters, are somewhat buried away on the individual data sheets for each glass. The designer is therefore faced quite often with the dilemma of which glass to select. This becomes particularly challenging when the designer has varied the refractive index and the Abbe number in his or her optimization, and the glass has settled into a moderately unpopulated region of the glass map. And to further complicate the task, the designer simply does not have the time or the patience to labor over hundreds of glass data sheets. Of the three major glass manufacturers (Schott, Ohara, and Hoya) Schott's glass map presents the user with glasses printed in red and glasses printed in black. The red glasses are "preferred," which means that the glasses are more readily available. It does not mean that the glasses are lower in cost, have better stain or bubble characteristics, or are easier to work. It simply means that they are more likely to be on the shelf. This may not be an optimum criteria from a producibility or a cost standpoint. The Hoya glass map presents the designer with glasses that are shown as either big red dots, big yellow dots, smaller green dots, very small purple dots, and lastly, very small blue dots. The large red dot glasses are "melted monthly in a large mass," the large yellow dot glasses are "melted monthly in a medium mass," and eventually the very small blue dot glasses are "melted rarely and may be discontinued in the future." In addition, the Hoya glass map adds the cost relative to that of BK7 in any of the large dot glasses. This is a very useful form of glass map; however, it still does not contain any information whatsoever regarding stain, bubbles, physical characteristics, or others. We decided it was time to come up with a comprehensive visually-based data base of optical glasses, and this paper will describe the GlassView program.
© (1991) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Robert E. Fischer, Michael J. Thomas, and Russell M. Hudyma "Optical glass selection using computerized data base", Proc. SPIE 1535, Passive Materials for Optical Elements, (1 November 1991); doi: 10.1117/12.48305; https://doi.org/10.1117/12.48305

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