Combination reflective and holographic weapon sight
A compact sight device has a housing with a viewing and a target end. A light source projects a light beam along a path. A holographic optical element (HOE) is disposed in the path of the light beam such that the HOE is illuminated by the light beam at an incidence angle defined with respect to a line perpendicular to the surface of the HOE. The HOE reconstructs an object beam with an image of a reticle, the object beam having an object beam angle measured with respect to the line perpendicular to the surface of the HOE. The incidence angle and the object beam angle are substantially equal. The HOE further reflects a portion of the light beam at a reflection angle substantially equal to the object beam angle such that a user viewing the object beam will also see a reflected image of the light source.
1. A compact sight device, comprising:
a housing having a viewing end and an opposing target end, a viewing path being defined from the viewing end to the target end;
a light source operable to project a light beam along a path;
a holographic optical element (HOE) disposed in the path of the light beam such that the HOE is illuminated by the light beam at an incidence angle defined with respect to a line perpendicular to a surface of the HOE, the HOE reconstructing an object beam with an image of a reticle, the reconstructed object beam having an object beam angle measured with respect to the line perpendicular to the surface of the HOE, the incidence angle and the object beam angle defined as being on opposite sides of the perpendicular line, the incidence angle and the object beam angle being substantially equal;
the HOE further reflecting a portion of the light beam at a reflection angle substantially equal to the reconstructed object beam angle such that a user viewing the object beam will also see a reflected image of the light source.
2. The compact sight device of claim 1 , wherein the light source has a laser diode operable to emit the beam of light when energized.
3. The compact sight according to claim 2 , wherein the laser diode is a vertical-cavity surface-emitting laser diode (VCSEL).
4. The compact sight device of claim 1 , further comprising a lens disposed in the path of the beam of light and operable to collimate the beam of light, the collimated beam of light illuminating the HOE.
5. The compact sight device of claim 1 , wherein a reconstructed reticle is without a center dot.
6. The compact sight device of claim 1 , further comprising a mirror disposed in the path of the light beam so as to reflect the beam of light onto the HOE.
7. The compact sight device f claim 1 , wherein the HOE is disposed in the viewing path.
8. The compact sight device of claim 1 , further comprising a non-diffraction element (NDE) reflecting the image of the reticle, the non-diffraction element being disposed in the viewing path such that a user views a target along the viewing path through the non-diffraction element from the viewing end; and the HOE is not disposed in the viewing path.
9. The compact sight device of claim 8 , wherein the non-diffraction element (NDE) is selected from the group consisting of a partial mirror, a glass element and an optical element with a dichroic film coating.
10. The compact sight device of claim 1 , wherein the compact sight is a weapon sight.