Topic
Angular aperture
About: Angular aperture is a research topic. Over the lifetime, 1771 publications have been published within this topic receiving 27257 citations.
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TL;DR: In this article, a free-form lens design is presented that can realize wide-angle imaging in conjunction with conventional imaging devices, and the surface profile of the freeform lens can be generated through solving a differential equation expressing the camera-viewing angle as a function of the angle of incidence on the free form lens surface.
15 citations
Patent•
02 Dec 1985TL;DR: In this article, a photographic objective comprising six lens elements is well-corrected for both monochromatic and chromatic aberrations, and is colorcorrected at four wavelengths in a band extending from the visible to the near infrared regions of the electromagnetic spectrum with only negligible secondary and high order spectra at wavelength between those for which color correction is achieved.
Abstract: A photographic objective comprising six lens elements is well-corrected for both monochromatic and chromatic aberrations, and is color-corrected at four wavelengths in a band extending from the visible to the near infrared regions of the electromagnetic spectrum with only negligible secondary and high-order spectra at wavelength between those for which color correction is achieved. The design form for the objective has been optimized for a focal length of 200 mm at an aperture ratio of f/4 and a field of view of 12° without vignetting.
15 citations
Patent•
14 Nov 2001
TL;DR: In this paper, the authors disclosed an objective lens for an optical disk, comprising a bi-aspherical single lens having a numerical aperture of 0.7 or more, wherein a center thickness of the lens is larger than a focal distance.
Abstract: There is disclosed an objective lens for an optical disk, comprising a bi-aspherical single lens having a numerical aperture of 0.7 or more, wherein a center thickness of the lens is larger than a focal distance.
15 citations
TL;DR: In this article, infrared images at 1.06 µm are up-converted in KDP with an angular aperture of more than 20° by scanning the orientation of the KDP, which is applicable when noncritical phase matching does not allow sufficient angular aperture.
Abstract: Infrared images at 1.06 μ are up-converted in KDP with an angular aperture of more than 20°. The images are up-converted by scanning the orientation of the KDP. The technique is applicable when noncritical phase matching does not allow sufficient angular aperture.
15 citations
TL;DR: It is generally accepted for optical apertures that obstructions of small proportions are relatively harmless for good imaging performance and that larger aperture obstructions should be avoided.
Abstract: It is generally accepted for optical apertures that obstructions of small proportions are relatively harmless for good imaging performance and that larger aperture obstructions should be avoided. This work presents some quantitative data on this subject. Optical simulation was used to measure parameters of images created by different families of aperture configurations. Twenty-four apertures were selected, and the following data given: aperture shape, energy portion within an area equivalent to the Airy disk and to a circle including the third bright ring of the ideal diffraction image, modulation transfer function, and a photograph of the diffraction image. Design criteria are discussed for aperture configurations of large telescope systems.
15 citations