Retroreflection defeat filter
AssigneeQioptiq Limited
InventorGiles Sheppard
Life of this patent
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Abstract
An optical system providing reduced retroreflection includes an optical element with an optic aperture. A retroreflection defeat filter has a partially obstructing material configured to absorb or reflect a subset of the optical system waveband while transmitting the rest. The partially obstructing material is arranged to occupy a first portion of the optic aperture being at least half of the optic aperture, and the partially obstructing material does not occupy a second portion of the optic aperture for the remainder of the optic aperture.
Claims13
An optical system with reduced retroreflection, comprising:
- an optical element comprising first and second optic apertures;
- first and second retroreflection defeat filters, each comprising a partially obstructing material configured to absorb or reflect a first portion of an optical system waveband while transmitting a second portion of the optical system waveband;
- wherein the partially obstructing material of the first retroflection defeat filter is arranged to occupy a first portion of the first optic aperture comprising at least half of the first optic aperture, and the partially obstructing material of the first retroflection defeat filter does not occupy a second portion of the first optic aperture comprising a remainder of the first optic aperture;
- wherein the partially obstructing material of the second retroflection defeat filter is arranged to occupy a first portion of the second optic aperture comprising at least half of the second optic aperture, and the partially obstructing material does not occupy a second portion of the second optic aperture comprising a remainder of the second optic aperture;
- and
- wherein the first and second retroflection defeat filters are arranged in opposite orientations.
A pair of retroreflection defeat filters for reducing retroreflection in an optical system comprising first and second optic apertures, the first retroflection defeat filter comprising:
- a partially obstructing material configured to absorb or reflect a first portion of an optical system waveband while transmitting a second portion of the optical system waveband, wherein the partially obstructing material of the first retroflection defeat filter is arranged to occupy a first portion of the first optic aperture comprising at least half of the first optic aperture;
- and
- the second retroflection defeat filter comprising:
- a partially obstructing material configured to absorb or reflect a first portion of an optical system waveband while transmitting a second portion of the optical system waveband, wherein the partially obstructing material of the second retroflection defeat filter is arranged to occupy a first portion of the second optic aperture comprising at least half of the first optic aperture;
- and
- wherein the first and second retroflection defeat filters are arranged in opposite orientations.
A method for a reduced retroreflection reduction filter for an optical system, comprising the steps of:
- providing a first retroflection defeat filter, the first retroflection defeat filter further comprising:
- a first portion of partially obstructing material configured to absorb part of an optical system waveband while transmitting another part of the optical system waveband;
- and
- a second portion not occupied by the partially obstructing material;
- positioning a first window within a first optic aperture of the optical system, wherein the window comprises the first retroflection defeat filter, and wherein the first portion occupies at least half of the first optic aperture;
- providing a second retroflection defeat filter, the second retroflection defeat filter further comprising:
- a first portion of partially obstructing material configured to absorb part of an optical system waveband while transmitting another part of the optical system waveband;
- and
- a second portion not occupied by the partially obstructing material;
- positioning a second window within a second optic aperture of the optical system, wherein the second window comprises the second retroflection defeat filter, and wherein the first portion occupies at least half of the second optic aperture;
- and
- wherein the first and second retroflection defeat filters are arranged in opposite orientations.
Dependencies are inferred from the claim text.