Angular aperture

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

Confocal arrangement for e.g. three-dimensional tooth shape measurement, has telecentric aperture arranged in internal focal plane of objective lenses to limit numerical aperture of lens, facing object, around specific value

Abstract: The arrangement has a telecentric aperture (7) and a trifocal diffractive lens (8) both arranged in a common internal focal plane of two objective lenses (6, 9). The diffractive lens outputs light beams exhibiting zero refractive power, negative and positive refractive power, respectively, upon receiving a beam from a light source. The aperture (7) limits numerical aperture of the lens (9), facing an object, around 0.025. An independent claim is also included for a confocal procedure.

Diffraction from a small square aperture:approximate aperture fields

Abstract: An approximate solution is presented that represents the first three terms in a more general expansion for the aperture electric field in a single, small square aperture (2a × 2a, ka ≪ 1) in a thin, perfectly conducting plane screen illuminated by a normally incident, linear polarized plane wave. The solution is motivated by physical intuition and the solutions for circular apertures and slits.Copson’s integrodifferential equation formulation [ Proc. R. Soc. London Ser. A202, 277 ( 1950)] of the boundary-value problem applied to small apertures is used to investigate the validity of the solution. Numerical calculations show that the solution for the dominant component of the electric field is valid over most of the aperture; its validity is in doubt in the close vicinity of the corners of the aperture. Higher-order terms are needed to describe the field accurately in this region.

Flexible scanning beam imaging system

Abstract: The present invention is directed to a flexible scanning beam imaging system. In specific embodiments, the scanning beam imaging system comprises a mask, and an objective lens having an objective lens focal point disposed between the mask and the objective lens. A field lens device is disposed before the mask to direct a light beam through the mask and focus the light beam at a field lens focal point. The field lens focal point is located between the field lens and the objective lens. One or more scanning mirrors are disposed at or near the objective lens focal point. As a result, the beam will be directed to different locations across the objective lens by the scanning mirror(s), and will travel from the objective lens substantially collimated and parallel toward a surface illuminated by the beam. This substantially collimated and parallel beam provides a large depth of field of the ablation pattern.