Angular aperture

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

Evaluation of Pupil-Filtering in High-Numerical Aperture I-Line Lens

Abstract: The pupil-filtering lens system for optical lithography experimentally evaluated in this study is based on an i-line stepper lens with a numerical aperture (NA) of 0.5, and its pupil function can be set arbitrarily to change the image characteristics. With the previously proposed super-FLEX filter, the depth of focus was three times that of the system without the filter, and the resolution for window patterns was 20% higher. Image characteristics of the filter, such as the edge-enhancing effect and the proximity effect, are discussed and were experimentally evaluated. The optical and mechanical tolerances required for this system are shown to be within ranges that are attainable in practical stepper systems.

Optical head device and optical information apparatus using the same

Abstract: An optical head device includes a focusing optical system for focusing a laser beam emitted from a semiconductor laser light source on an optical information medium with an objective lens. A chromatic aberration correction element for correcting chromatic aberration occurring in the objective lens is provided between the semiconductor laser light source and the optical information medium. A light distribution correction element in which the transmittance increases with the distance from the center of the aperture surface of the objective lens is provided so as to correct a reduction of the intensity of the light incident on the aperture surface of the objective lens with the distance from the center of the aperture surface.

Infrared radiation detector with integral fresnel lens window

Abstract: An infrared radiation detector comprises a pyroelectric detector element in a hermetically sealed housing. The housing comprises a base and cover with an aperture. A Fresnel lens, for example made of polyethylene transmissive in the 8-14 μm wavelength range, is fastened over the aperture on the inside of the cover for condensing the radiation to be detected onto the detector element. In one example the Fresnel lens is held against a flange surrounding the aperture by a press-fit ring. Alternatively, the Fresnel lens is glued to a silicon window which in turn is fastened to the flange surrounding the aperture. The Fresnel lens thus forms an integral part of the detector housing avoiding the need for external mirrors or lenses.