Topic
Moiré pattern
About: Moiré pattern is a research topic. Over the lifetime, 1917 publications have been published within this topic receiving 27176 citations. The topic is also known as: moiré fringes & moire pattern.
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01 Jun 1990
TL;DR: In this paper, a new precise alignment technique using optical phase shifting, Fourier transform and spatial filtering has been developed for registering a symmetric pattern on the substrate to a phase-shifting pattern on reticle.
Abstract: A new precise alignment technique using optical phase-shifting, Fourier transform and spatial filtering has been developed for registering a symmetric pattern on the substrate to a phase-shifting pattern on the reticle. The alignment between two marks was determined by detecting a minimum point in the zero order spatial frequency intensity of the light reflected from the alignment mark on the substrate. The minimum is due to the complete phase-cancellation when the alignment marks co-centered. The theoretical analysis and computer simulations were performed to show that this technique is not affected by variations of linewidth and step height of the alignment mark pattern as well as variations of optical properties of the substrate in which the alignment mark is built. The preliminary experimental results were in good agreement with the calculations. It has been shown that this technique does not have the alignment ambiguity problem existed in the techniques using grating pattern and detecting interference moire image. Current results indicate that the overlay accuracy of the technique can be better than 0. 1 .tm.
01 Jan 1993
TL;DR: Moire principles are applied to the measurement of the spindle radial error motion in this article, where two periodic circular gratings are used, one on a spindle and the other held stationary on the reference frame.
Abstract: Moire principles are applied to the measurement of the spindle radial error motion. As opposed to conventional techniques, no master cylinder or ball is needed in the measurement so that the offset and out—of—roundness errors of the master can be inherently eliminated. Two periodic circular gratings are used, one is made on the spindle and the other is held stationary on the reference frame. When the two gratings are seen superimposed during spindle rotation, an interference fringe pattern is observed from which the information on the eccentricity between the two gratings can be extracted with high precision. The optical design and fringe analysis techniques of a prototype measurement system are described in detail with exemplary measurement results.
TL;DR: A novel method based on monitoring the Moiré pattern using a simple dispersive planoconvex lens (chromatic aberration) for wavelength alteration measurement is reported, which is simple and more reliable, and might find wide applications in spectrometry, optical sensors, and dispersion measurements.
Abstract: For convenient measurements in many applications, wavelength alterations should be translated to the change in intensity of the output light. In this Letter, a novel method based on monitoring the Moire pattern using a simple dispersive planoconvex lens (chromatic aberration) for wavelength alteration measurement is reported. Due to the chromatic aberration of the lens, different wavelengths have different magnifications. This causes rotation in the Moire pattern when the wavelength of the incident light is changed. It is shown that by measuring this rotation it is possible to measure the wavelength alterations. The experimental results obtained from four different laser sources with 450, 532, 630, and 632.8 nm wavelengths show total Moire pattern rotation of about 31.5°, which shows good theory–experimental agreement. This method is simple and more reliable, and might find wide applications in spectrometry, optical sensors, and dispersion measurements.
TL;DR: In this article, a simple method is proposed for obtaining moire patterns, and information is given on the deformation of curved surfaces. The experimental arrangement is based on the projection-moire principle and consists of a projector and a camera.
Abstract: A simple method is proposed for obtaining moire patterns, and information is given on the deformation of curved surfaces. The experimental arrangement is based on the projection-moire principle and consists of a projector and a camera. A transparent object, e.g., a shell with line gratings, is projected onto the focal plane of this projector and superposed there with a reference grating which describes the undeformed state of the curved surface in the form of a transparent picture. Moire patterns are obtained by simultaneously superposing the projected line grating in the shell's deformed state and the reference grating. They present a general picture of the behavior of the object during loading, such as during impact if the patterns are recorded with a high-speed camera.
TL;DR: In this paper, Moire patterns during digital recording and reconstruction of Fresnel holograms have been analyzed for 1-D and 2-D objects, and the elimination of these Moire pattern can be achieved using pulsed, instead of CW, illumination.
Abstract: Moire patterns during digital recording and reconstruction of Fresnel holograms have been analyzed for 1-D and 2-D objects. Elimination of these Moire patterns can be achieved using pulsed, instead of CW, illumination.