scispace - formally typeset
Search or ask a question
Topic

Angular aperture

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


Papers
More filters
Patent
18 Jan 2001
TL;DR: In this paper, a highly reflective diffusely illuminated cavity source (11) has apertures (12) which allow the selected radiation to pass through directly over a first range of angles, and any radiation not entering an aperture is reflected inside the reflective cavity from the wall which has low absorption and is diffusely reflected from another cavity wall.
Abstract: This invention concerns the production of a large-area collimated beam of radiation for use in displays. A highly reflective diffusely illuminated cavity source (11) has apertures (12) which allow the selected radiation to pass through directly over a first range of angles. Each aperture (12) has a finite depth and angled sides tapering outwardly so that the radiation which enters the aperture at a second, larger range of angles impinges on the walls (6) of the aperture and is redirected into a preferred direction by reflection at the walls of the aperture. Any radiation not entering an aperture is reflected inside the reflective cavity from the wall which has low absorption and is diffusely reflected from another cavity wall (30), so that it has a finite probability of entering any one of the array of apertures. In this way the light that has not entered an aperture will be randomly reflected back to try again.

6 citations

Journal ArticleDOI
TL;DR: In this article, the chromatic and aperture aberrations of crossed five-aperture lenses are analyzed by direct ray tracing, and it is shown that the first-order properties of the crossed lens are similar to those of a quadrupole doublet.
Abstract: The chromatic and aperture aberrations of crossed five‐aperture lenses are analyzed by direct ray tracing. The apertures are rectangular and the voltages are applied in such a way that the first‐order properties of the crossed lens are similar to those of a quadrupole doublet. It is shown that in astigmatic modes the chromatic and aperture aberrations of one of the linear images can be simultaneously eliminated or made negative. It is also shown that stigmatic modes exist in which the magnification is different in two perpendicular planes and in which the image blurring caused by the chromatic and aperture aberrations in the direction of smaller magnification is ten times smaller than that given by a round lens of the same focal length and the blurring in the other direction is at least two times smaller. The stigmatic crossed lens also gives a larger working distance than the equivalent round lens. The crossed lens will therefore be preferable for many probe forming systems.

6 citations

Patent
30 Apr 2003
TL;DR: In this article, a purely refractive projection lens comprising an extremely large aperture was proposed, which is characterized by a high numeric aperture, few chromatic aberrations and a compact, material-saving structure.
Abstract: The invention relates to a purely refractive projection lens comprising an extremely large aperture. Said projection lens is embodied as a double-convexity system having one convexity on the object side, one convexity on the image side, and a throat (7) which is located between the same. The system diaphragm (5) is arranged at a distance from the image plane in the convexity on the image side. A negative group (LG5) is arranged between the throat and the system diaphragm in the region of the divergent radiation, said negative group having an effective swell with a concave side oriented towards the image plane. The system is characterised by a high numeric aperture, few chromatic aberrations and a compact, material-saving structure.

6 citations

Patent
13 Feb 1990
TL;DR: In this article, a wide-angle objective for a picture-taking lens of an aerial mapping camera, consisting of 11 lenses and 14 glass-air surfaces, is presented, where the first optical element of which after the center aperture on the picture side is a converging fluorspar or fluorpar-like lens.
Abstract: A wide-angle objective for a picture-taking lens of an aerial mapping camera, consisting of 11 lenses and 14 glass-air surfaces, the first optical element of which after the center aperture on the picture side is a converging fluorspar or fluorspar-like lens. Due to the large refractive index difference between this lens and the following meniscus lens and due to the provision of a triple group of high refractive index on the object side before the center aperture, a high resolution, low residual distortion and minimal lateral chromatic aberration are achieved.

6 citations

Journal ArticleDOI
TL;DR: In this paper, the authors discussed the importance of the aperture size in determining the off-axis behavior of a spherically spreading, conical primary beam of finite initial aperture.
Abstract: It is well known that the beam pattern of a parametric acoustic source whose difference frequency is generated largely within the nearfield of the primary beam includes a multiplicative aperture factor that can be important at large angles when ka≳1 (k is the difference frequency wave number, a is the aperture radius). Not so well known, however, is the fact that the same aperture factor arises in the case of a spherically spreading, conical primary beam of finite initial aperture. The importance of the aperture size in determining the off‐axis behavior of parametric sources is discussed.Subject Classification: [43]25.35; [43]20.30; [43]30.75.

6 citations


Network Information
Related Topics (5)
Amplifier
163.9K papers, 1.3M citations
70% related
Resonator
76.5K papers, 1M citations
70% related
Photonic crystal
43.4K papers, 887K citations
69% related
Polarization (waves)
65.3K papers, 984.7K citations
69% related
Optical fiber
167K papers, 1.8M citations
68% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20234
20224
20217
20207
20195
201811