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Angular aperture

About: Angular aperture is a research topic. Over the lifetime, 1771 publications have been published within this topic receiving 27257 citations.


Papers
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Patent
20 Sep 2004
TL;DR: In this paper, the authors present a projection lens assembly with an initial negative lens (20), a second positive lens (22), a third biconvex lens (24), a fourth biconcave lens (26), a fifth biconceve lens (28), a sixth biconciax lens (30), a seventh biconciaux lens (31), and a twophase lens (32).
Abstract: The lens for a cinema projector has a short focal length and a high start opening. The sum of the lens length and the back focal distance is 2.8-4.5 times the total focal length. The entry pupil is 100-300 mm from the final lens surface (62) towards the illumination mirror. The minimum diaphragm opening is 1.7, and can be used with an illuminating mirror with an opening angle up to 17[deg]. The projection lens assembly has an initial negative lens (20), a second positive lens (22), a third biconvex lens (24), a fourth biconcave lens (26), a fifth biconcave lens (28), a sixth biconvex lens (30) and a seventh biconvex lens (32).

22 citations

Patent
16 Oct 2013
TL;DR: An optical imaging lens assembly includes, in order from the object side to the image side, a first lens element, a second lens, a third lens, an aspheric lens element and a sixth lens element as mentioned in this paper.
Abstract: An optical imaging lens assembly includes, in order from the object side to the image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element and a sixth lens element The first lens element with positive refractive power has a convex object-side surface in a paraxial region The fourth lens element with negative refractive power has a concave object-side surface in a paraxial region The fifth lens element with positive refractive power has a convex image-side surface in a paraxial region The sixth lens element with negative refractive power has a concave object-side surface in a paraxial region, a concave image-side surface in a paraxial region and at least one convex shape in the off-axial region of the image-side surface of the sixth lens element The fifth lens element and the sixth lens element are aspheric lens elements

22 citations

Journal ArticleDOI
TL;DR: In this article, the effects of such phase and amplitude coatings on the imaging properties of a lens can be achieved by using suitably oriented polarization masks on the lens aperture, which can be continuously varied by changing the orientation of the polarizing devices included in the system.
Abstract: It is well known that circular symmetric phase and amplitude coatings on the lens aperture modify the imaging qualities of a lens. The present paper shows that the effects of such phase and amplitude coatings on the imaging properties of a lens can be achieved by using suitably oriented polarization masks on the lens aperture. The fact that the response of such a system can be continuously varied by changing the orientation of the polarizing devices included in the system lends it a versatility unobtainable by the use of conventional phase and amplitude coatings on the lens aperture.

22 citations

Journal ArticleDOI
Ting-Chung Poon1
TL;DR: In this paper, a simple Fourier-Optic approach is used to calculate the field distribution around the geometrical focus of a plane wave through an annular aperture lens, and the results indicate that the amount of focal shift depends on the Fresnel number of the circular aperture lens as well as the central obscuration ratio of the annulus.

22 citations

Patent
04 Apr 1981
TL;DR: In this paper, a curved reflector of electro-magnetic radiation formed of an elastic, reflective membrane (14) which utilizes a partial vacuum to provide the curvature to the membrane and an adjustablevalve (20) to vary such curvature, and therefore the focal length of the reflector.
Abstract: A curved reflector (10) of electro-magnetic radiation formed of an elastic, reflective membrane (14) which utilizes a partial vacuum to provide the curvature to the membrane (14) and an adjustablevalve (20) to vary such curvature, and therefore the focal length of the reflector (10). The valve (20) comprises a central aperture in the membrane (14) and a body adjustably mounted above the aperture with a flow restricting surface thereon which overlies the aperture.

22 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20234
20224
20217
20207
20195
201811