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, the intensity distribution of a Gaussian Schell-model (GSM) beam diffracted at an aperture lens is studied. But the authors focus on the system of different Fresnel numbers, which focus GSM beams.
Abstract: Starting from the generalized Huygens-Fresnel diffraction integral, we study the intensity distribution of a Gaussian Schell-model (GSM) beam diffracted at an aperture lens. A great number of numerical calculations have been performed to illustrate the focused field characteristics. Isophote diagrams are given for systems of different Fresnel numbers, which focus GSM beams, and the related analysis is presented.
10 citations
Patent•
23 May 2005
TL;DR: In this paper, a brightness enhancement article (30) has a plurality of light collecting structures (32), wherein each light collecting structure (32) is longitudinally extended in a length direction along the surface.
Abstract: A brightness enhancement article (30) provides light from a two-dimensional surface. The brightness enhancement article (30) has a plurality of light collecting structures (32), wherein each light collecting structure (32) is longitudinally extended in a length direction along the surface. Each light collecting structure (32) has an input aperture (33) optically coupled to a light-providing surface and an output aperture (35) distal from the input aperture (33), wherein the output aperture (35) has a surface area that is larger than the surface area of the input aperture (33). A pair of curved side walls (38) extend from the output aperture (35) toward the input aperture (33). In a cross section taken orthogonally with respect to the length direction, the curved side walls (38) approximate a parabolic curvature.
10 citations
TL;DR: Findings are reexamined, that the point of the principal maximum of axial irradiance is not at the geometrical focus but shifted toward the aperture in systems of different relative aperture and finite value of Fresnel number.
Abstract: In their work on diffraction [J. Opt. Soc. Am.51, 1050 1961], Osterberg and Smith have computed in an exact manner from the Rayleigh-Sommerfeld diffraction integral of the first kind the irradiance distribution along the axis of a converging spherical wave, and they found that in a scalar optical system of high relative aperture and finite value of Fresnel number, the central peak value of the axial irradiance may occur inside, at, or outside the geometrical focal point as the angular semiaperture of the system is less than, equal to, or greater than, respectively, a particular angle that falls near 70°. These findings are now reexamined using a different assumption that takes into account diffraction at the edge of the aperture. Different results are obtained that agree well with the predictions of other theories of diffraction of light and give confidence to the common conclusions drawn by investigators of the effect of focal shift, that the point of the principal maximum of axial irradiance is not at the geometrical focus but shifted toward the aperture in systems of different relative aperture and finite value of Fresnel number.
10 citations
Patent•
24 Apr 1978
TL;DR: In this paper, an improved lens arrangement is provided for a camera of the type having a focal plane and a subject-to-camera distance responsive effective maximum aperture limiting control arrangement operatively disposed with respect to the focal plane.
Abstract: An improved lens arrangement is provided for use in a camera of the type having a focal plane and a subject-to-camera distance responsive effective maximum aperture limiting control arrangement operatively disposed with respect to the focal plane. The improved lens arrangement has a reverse spherical aberration corrective characteristic which operates to reduce the effective circles of confusion associated with each of the images of different subjects within a given range of distances from the camera as formed at the focal plane by the lens arrangement in combination with the effective aperture control arrangement.
10 citations
Patent•
27 Dec 1994TL;DR: In this paper, a 1-st lens unit has a positive refractive power which has at least two positive lens elements and a negative lens element positioned on an image side of said positive lenses.
Abstract: The lens system includes, in order from an object side, a 1-st lens unit having a positive refractive power which has at least two positive lens elements and a negative lens element positioned on an image side of said positive lens elements, a 2-nd lens unit having a positive refractive power and a 3-rd lens unit having a positive refractive power. During focusing, both 1-st and 3-rd lens units are fixed, whereas the 2-nd lens unit is movable along an optical axis. The lens system satisfies at least one of the conditions 1.8
10 citations