Wide angle high speed lens

• Publisher: Elsevier Science
• Year: 1931
• Tongue: English
• Weight: 384 KB
• Volume: 212
• Category: Article
• ISSN: 0016-0032
• DOI: 10.1016/s0016-0032(31)90800-4

✦ Synopsis

This is a wide angle doublet lens designed to cover a wide field with flatness of field, with freedom from distortion and flare, corrected for astigmatism and for both chromatic and spherical aberration.

This objective is designed for astronomical work and is of the type that includes two spaced components each of which may be a compound lens, one element being positive and the other negative.

The United States patent shows two combinations of lenses that meet the requirements. Figure I, made from a drawing in the patent, shows one form in which the negative lens of the doublet is on the left and is the front lens of the telescope.

The three parts of this component are in contact and consist of L', a biconvex lens of highly refractive flint glass, a biconcave lens, L 3, of the same, and between them a positive meniscus lens, L 2, of crown glass of low refractive index. The positive component of this doublet includes a positive lens L 5, of barium crown glass and a negative lens, L 4, of glass having a much lower index of refraction.

Wideness of field is secured by making the components of considerable thickness and the inventor finds that the errors are best compensated by placing this thickness in the meniscus lens of the negative component.