Patent ID: 6327806
Filing Date: 2001-12-11
Classification: F41G,G02B

Abstract:
An optical device for sighting a target to be aimed at in the line of sight of a user, comprising:an optical element of transparent material having a first surface to be in use directed towards the target and a second surface in which the user views an image of the target, anda source of light directed at and reflected back from the second surface to create a sighting image for the user to align with the image of the target as viewed in the optical element,wherein the optical element is a thick meniscus optical element--namely one having a thickness at least approximately 25% of the effective diameter of the optical element--and is composed of a base element which(a) provides said second surface as a parabolic aspherical surface and defines it as one of short focal length, namely less than 5 cm (2 inches), and which(b) has an aspherical correcting surface that constitutes said first surface and is to minimize aberrations in the image of the target as viewed by the user.