Topic
Fresnel zone
About: Fresnel zone is a research topic. Over the lifetime, 2337 publications have been published within this topic receiving 37650 citations.
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Patent•
30 Sep 1980
TL;DR: In this article, a pinhole plate and a photo detector are moved together along the optical axis to find such a position of the photo detector that an ammeter reads the highest value in the reading.
Abstract: PURPOSE:To achieve a simultaneous measurement of a focal distance and diffusing property in a handy and accurate manner for a Fresnel lens of a single lens reflex camera CONSTITUTION:A light from the pin hole of a chart 4 is made parallel with a collimeter lens 5 and enters a Fresnel lens 6 to be measured The parallel light flux converges on a certain point after passing the Fresnel lens 6 A pinhole plate 7 and a photo dtector 8 are moved together along the optical axis to find such a position of the photo detector 8 that an ammeter 9 rises to the highest value in the reading At this point, the distance between the Fresnel lens 6 and the photo detection surface of the pin hole plate 7 is measured to obtain the focal distance of the lens 6 When the peak of the measured value is compared with the peak value previously obtained from a sample master having a mat surface arranged to be varied in the roughness, the diffusion peroperty of the Fresnel lens can be determined as well
10 citations
TL;DR: In this article, a tunable dye laser was used for the illumination of a single piece of frosted glass and for pairs with controlled separation to obtain the intensity versus frequency data.
10 citations
Patent•
19 Jan 1988
TL;DR: A Fresnel zone-plate reflector of a transmitting/receiving antenna contains a flat metal reflector and a plurality of concentrically arranged metal circular rings in a plane parallel to the reflector at a spacing of a quarter of a wavelength.
Abstract: A Fresnel zone-plate reflector of a transmitting/receiving antenna contains a flat metal reflector and a plurality of concentrically arranged metal circular rings in a plane parallel to the reflector and at a spacing of a quarter of a wavelength, such that the wave elements of a spherical wave front reflected on the circular rings are added in the correct phase to the wave elements reflected (in the ideal case) on the reflector surface, to form a flat wave front.
10 citations
TL;DR: In this article, conditions for the removal of unwanted diffraction orders by a combination of an axial stop and a pinhole are examined, and the effect of these obstructions on the image quality is discussed.
Abstract: Fresnel zone plates are considered as imaging elements for soft X-ray microscopy. Conditions for the removal of unwanted diffraction orders by a combination of an axial stop and a pin-hole are examined. The effect of these obstructions on the image quality is discussed.
10 citations
01 Jun 2017
10 citations