United States Patent
US Patent 3942901: Optical sighting instrument with means for…
US 3942901 · granted 1976-03-09
| Patent Number | 3942901 |
|---|---|
| Title | Optical sighting instrument with means for producing a sighting mark |
| Filed | 1973-12-07 |
| Granted | 1976-03-09 |
| Inventor(s) | John Arne Ingemund Ekstrand |
| Assignee | Individual |
| CPC Classification | G02B27/30, G02B30/00, G02B26/00 |
| Number of Claims | 2 |
Abstract
An optical instrument comprising a lens means having a concave light reflecting surface serving as a semi-transparent mirror, and a light source for directing light beams to the semi-transparent mirror which is arranged to produce an image of the light source, such that said image to an observer who has his eye directed to the concave mirror surface appears to lie far in front of the mirror to serve as a sighting mark on a sighting line between the observer’s eye and a target; the lens means with the semi-transparent concave mirror surface and the light source being arranged such in relation to each other and in relation to the sighting line that the optical main axis from the light source to the lens means intersects the sighting line substantially on the semi-transparent mirror surface and intersects the theoretical optical main axis of the lens means in a point situated close to the focus of the concave mirror surface, and such that the focus and said point are transversely spaced from the sighting line whereby sighting errors as a result of misalignment of the observer’s eye in relation to said sighting line will be reduced to a minimum.
Claims Summary
1. A sighting instrument having front and rear ends and comprising a lens means mounted at said front end of the instrument and including a semi-transparent concave mirror surface facing said rear end of the instrument to be viewed therefrom and having its axis directed such that the focus of said concave mirror surface is offset from the sighting line of said instrument, and a light source having a light emitting surface positioned substantially at the focus of said concave mirror surface for directing light onto said concave mirror surface to produce a confined image of said light emitting surface, which is useful as a sighting mark and which to an observer who has his eye directed to said mirror surface in a distance rearwardly thereof, appears to lie in front of the mirror on the sighting line between the observer’s eye and a target, said lens means with said concave mirror surface and said light source being arranged such in relation to each other and to said sighting line tha