Rear aperture sight for rifle

Abstract

A rear aperture sight for use in conjunction with a front sight post sight on a rifle. The front sight post has a horizontal top edge and vertical side edges. The rear aperture sight comprises a rear sight adapted to be mounted on the rifle. The rear sight has a horizontally elongated aperture formed therein having height and width dimensions. The width dimension is greater than the height dimension. The aperture is defined by two circular segments s1 and s2 having chords c1 and c2, respectively, defined by included angles θ1 and θ2, respectively, of circles having radii R1 and R2, respectively. The chords c1 and c2 have heights h1 and h2, respectively. Radii R1 and R2 and angles θ1 and θ2 are selected such that chords c1 and c2 are of equal length. The circular segments are positioned such that chords c1 and c2 are co-linear and oriented horizontally. In another aspect, the rear sight has at least one aperture plate having an aperture formed therein which defines an entrance pupil for an eye of a shooter of the rifle. The entrance pupil is horizontally elongated having a height h and a width w, the width w being at least about 125% of the height h, the height h being smaller than a diameter of a pupil of the eye of the shooter and of such a value that the entrance pupil is adapted to cause the horizontal top edge of the front sight post and a horizontal edge of a target to be more sharply focused than if viewed by an unaided eye, the width w being of such a value that an area defined by the entrance pupil is greater than an area defined by a circular entrance pupil having a diameter equal to the height h, thereby permitting more light to pass through the entrance pupil than through the circular entrance pupil, and causing the front sight post and the target to appear brighter than if viewed through the circular entrance pupil.

Description

RELATED APPLICATIONS[0001]This application is a continuation-in-part of application Ser. No. 11 / 957,963, which is a continuation-in-part of application Ser. No. 11 / 619,953, and a continuation-in-part of application Ser. No. 11 / 619,953, both of which are hereby incorporated by reference herein as if fully set forth in their entirety.FIELD OF THE INVENTION[0002]This invention relates generally to firearms, and more particularly to sighting systems for firearms.BACKGROUND OF THE INVENTION[0003]The depth of field of an optical system, including the human eye, is defined in part by the diameter of the “entrance pupil” to that optical system. The entrance pupil diameter is that dimension which is used, along with a lens focal length, to calculate a lens f-ratio, and which is in turn used to calculate depth of field. An entrance pupil is the projection along the optical axis, towards the first lens surface of an optical system, of an aperture which limits the entry of light beams into that...

AI Technical Summary

Benefits of technology

"The present invention is a rear aperture sight for use in conjunction with a front sight post on a rifle. The rear aperture sight has a horizontal top edge and vertical side edges. It includes a rear sight with a round aperture that is formed at an angle to the face of the rear sight. The aperture has a width dimension that is greater than its height dimension. The width dimension is greater than the pupil of the eye, which creates a horizontally elongated entrance pupil that allows for sharp focusing on the front sight post and target. The rear aperture sight also includes a front sight post with a horizontal top edge and vertical side edges. The front sight post has a round aperture with the same dimensions as the rear aperture sight. The rear aperture sight and front sight post work together to provide a more precise and accurate sight for hunting and targeting."

Problems solved by technology

A distinct disadvantage in using the smaller rear circular aperture is that less light is permitted to pass through the aperture.

Thus, even though the horizontal top edge and vertical side edges of the front sight post and target are clearly focused, which enhances accuracy in aiming and hence accuracy in shot placement, the front sight post and target are nevertheless dim, which hinders accuracy in aiming ability and hence accuracy in shot placement.

A problem with traditional round aperture sights is that once the aperture is reduced in size to provide optimal focus on the horizontal top edge of the front sight post and the horizontal bottom edge of the target, the amount of light passing through the opening is so limited that the target and the front sight post appear dim to the shooter.

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