US 5,179,630 AGranted

Laser protection window with tilted modulated index of refraction filter elements

AssigneeKaiser Optical Systems

InventorsByung J. Chang, James M. Tedesco

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Abstract

The present invention is a technique for construction of a laser protection window providing broadened angular protection. Plural modulated index of refraction filter elements are constructed to reflect incident light at a predetermined laser threat wavelength over a cone of protection. The plurality of modulated index of refraction filter elements are disposed in tandem at angles to a direction of primary view through the laser protection window which are symmetrical with respect to the direction of primary view. In a first embodiment, a first optional modulated index of refraction filter element is disposed perpendicular to the direction of primary view; the other modulated index of refraction filter elements are disposed in pairs at opposing angles to the direction of primary view. In an alternative embodiment, the angled modulated index of refraction filter element plates are formed of angled segments. The plural modulated index of refraction filter elements may be angled in two planes to provide extended angular coverage both horizontally and vertically.

Claims25

Dependent claims

A laser protection window comprising:

a first planar modulated index of refraction filter element having a spatially modulated index of refraction therein for reflecting light at a predetermined wavelength which has an angle of incidence to the perpendicular of said first modulated index of refraction filter element of less than a first blocking angle, said first planar modulated index of refraction filter element disposed perpendicular to the direction of primary view through the laser protection window;
a set of a plurality of second planar modulated index of refraction filter element segments, each second planar modulated index of refraction filter element segment having a spatially modulated index of refraction therein for reflecting light at said predetermined wavelength which has an angle of incidence to the perpendicular of said second planar modulated index of refraction filter element segment of less than a second blocking angle, each of said second planar modulated index of refraction filter element segments disposed at a predetermined angle to the direction of primary view through the laser protection window in tandem with a unique portion of said first planar modulated index of refraction filter element;
and
a set of a plurality of third planar modulated index of refraction filter element segments, each third planar modulated index of refraction filter element segment having a spatially modulated index of refraction therein for reflecting light at said predetermined wavelength which has an angle of incidence to the perpendicular of said third planar modulated index of refraction filter element segment of less than said second blocking angle, each of said third planar modulated index of refraction filter element segments disposed at an angle to the direction of primary view through the laser protection window opposite to said predetermined angle in tandem with a unique portion of said first planar modulated index of refraction filter element.

1 more element

A laser protection window comprising:

a set of a plurality of first planar modulated index of refraction filter element segments, each first planar modulated index of refraction filter element segment having a spatially modulated index of refraction therein for reflecting light at said predetermined wavelength which has an angle of incidence to the perpendicular of said first planar modulated index of refraction filter element segment of less than a blocking angle, each of said first planar modulated index of refraction filter element segments disposed at a predetermined angle to the direction of primary view through the laser protection window;
and
a set of a plurality of second planar modulated index of refraction filter element segments, each second planar modulated index of refraction filter element segment having a spatially modulated index of refraction therein for reflecting light at said predetermined wavelength which has an angle of incidence to the perpendicular of said second planar modulated index of refraction filter element segment of less than said blocking angle, each of said second planar modulated index of refraction filter element segments disposed at an angle to the direction of primary view through the laser protection window opposite to said predetermined angle, said plurality of second planar modulated index of refraction filter element segments together being disposed in tandem with said plurality of first planar modulated index of refraction filter element segments.

A laser protection window comprising:

a plurality of planar modulated index of refraction filter elements, each having a corresponding depth and a spatially modulated index of refraction therein solely dependent on depth for reflecting light at a predetermined wavelength which has an angle of incidence to the perpendicular of said planar modulated index of refraction filter element of less than a respective blocking angle, said plurality of planar modulated index of refraction filter elements disposed in tandem at corresponding angles to a direction of primary view through the laser protection window, the set of corresponding angles of said plurality of planar modulated index of refraction filter elements being fixed upon manufacture, symmetrical with respect to the direction of primary view through the laser protection window and selected in related to said respective blocking angles, wherein said plurality of planar modulated index of refraction filter elements consists of
a first modulated index of refraction filter element disposed perpendicular to the direction of primary view through the laser protection window,
a second modulated index of refraction filter element disposed at a predetermined angle within a horizontal plane to the direction of primary view through the laser protection window, and
a third modulated index of refraction filter element disposed at an angle within a horizontal plane to the direction of primary view through the laser protection window opposite to said predetermined angle,
whereby light having an angle of incidence to the perpendicular of said laser protection window within an extended continuous angular range is within said blocking angle of at least one of said planar modulated index of refraction filter elements.

2 more elements

A laser protection window comprising:

a plurality of planar modulated index of refraction filter elements, each having a corresponding depth and a spatially modulated index of refraction therein solely dependent on depth for reflecting light at a predetermined wavelength which has an angle of incidence to the perpendicular of said planar modulated index of refraction filter element of less than a respective blocking angle, said plurality of planar modulated index of refraction filter elements disposed in tandem at corresponding angles to a direction of primary view through the laser protection window, the set of corresponding angles of said plurality of planar modulated index of refraction filter elements being fixed upon manufacture, symmetrical with respect to the direction of primary view through the laser protection window and selected in related to said respective blocking angles, wherein said plurality of planar modulated index of refraction filter elements includes
at least one first modulated index of refraction filter element disposed at a corresponding first predetermined angle within a horizontal plane to the direction of primary view through the laser protection window,
at least one second modulated index of refraction filter element, each second modulated index of refraction filter element corresponding to one of said first modulated index of refraction filter elements, each second modulated index of refraction filter element disposed at an angle within a horizontal plane to the direction of primary view through the laser protection window opposite to said first predetermined angle of said corresponding first modulated index of refraction filter element,
at least one third modulated index of refraction filter element disposed at a corresponding second predetermined angle within a vertical plane to the direction of primary view through the laser protection window, and
at least one fourth modulated index of refraction filter element, each fourth modulated index of refraction filter element corresponding to one of said third modulated index of refraction filter elements, each fourth modulated index of refraction filter element disposed at an angle within a vertical plane to the direction of primary view through the laser protection window opposite to said third predetermined angle of said corresponding third modulated index of refraction filter element,
whereby light having an angle of incidence to the perpendicular of said laser protection window within an extended continuous angular range is within said blocking angle of at least one of said planar modulated index of refraction filter elements.

3 more elements

A method of construction of a laser protection window comprising the steps of:

constructing first, second, and third substantially identical planar modulated index of refraction filter elements, each planar modulated index of refraction filter element having a corresponding depth and a spatially modulated index of refraction therein solely dependent on depth for reflecting light at a predetermined wavelength which has an angle to the perpendicular of said planar modulated index of refraction filter element of less than a respective blocking angle;
and
disposing said planar modulated index of refraction filter elements in tandem at corresponding angles to a direction of primary view through the laser protection window such that said first modulated index of refraction filter element is disposed perpendicular to the direction of primary view through the laser protection window, said second modulated index of refraction filter element is disposed in tandem with said first modulated index of refraction filter element at a predetermined angle to the direction of primary view through the laser protection window, and said third modulated index of refraction filter element is disposed in tandem with said first and second modulated index of refraction filter elements at an angle to said direction of primary view through the laser protection window opposite to said predetermined angle, the set of corresponding angles of said plurality of planar modulated index of refraction filter elements being fixed and manufactured, symmetrical with respect to the direction of primary view through the laser protection window and selected in relation to said respective blocking angles,
whereby light having an angle of incidence to the perpendicular of said laser protection window within an extended continuous angular range is within said blocking angle of at least one of said planar modulated index of refraction filter elements.

1 more element

A method of construction of a laser protection window comprising the steps of:

constructing a plurality of substantially identical planar modulated index of refraction filter elements, each planar modulated index of refraction filter element having a corresponding depth and a spatially modulated index of refraction therein solely dependent on depth for reflecting light at a predetermined wavelength which has an angle to the perpendicular of said planar modulated index of refraction filter element of less than a respective blocking angle;
disposing said plurality of planar modulated index of refraction filter elements in tandem at corresponding angles to a direction of primary view through the laser protection window, the set of corresponding angles of said plurality of planar modulated index of refraction filter elements being fixed and manufactured, symmetrical with respect to the direction of primary view through the laser protection window and selected in relation to said respective blocking angles;
disposing a first transparent plate formed of shatter proof material at an exterior end of the tandem arrangement of said plurality of modulated index of refraction filter elements;
and
disposing a second transparent plate formed of a shatter proof material at an interior end of the tandem arrangement of said plurality of modulated index of refraction filter elements,
whereby light having an angle of incidence to the perpendicular of said laser protection window within an extended continuous angular range is within said blocking angle of at least one of said planar modulated index of refraction filter elements.

3 more elements

A method of construction of a laser protection window comprising the steps of:

constructing a plurality of substantially identical planar modulated index of refraction filter elements, each planar modulated index of refraction filter element having a corresponding depth and a spatially modulated index of refraction therein solely dependent on depth for reflecting light at a predetermined wavelength which has an angle to the perpendicular of said planar modulated index of refraction filter element of less than a respective blocking angle;
said step of constructing each of said plurality of substantially identical modulated index of refraction filter elements including
disposing a layer of photosensitive material on one surface of a transparent supporting substrate thereby forming a photosensitive layer having an open surface,
disposing a reflecting surface on said open surface of said photosensitive layer,
exposing said photosensitive layer to coherent light illumination via said transparent supporting substrate thereby forming interference fringes therein from light directly incident upon said photosensitive layer and light reflected from said reflecting surface,
removing said reflecting surface from said open surface of said photosensitive layer after said exposure, and
developing said exposed photosensitive layer thereby forming a modulated index of refraction filter element having interference fringes corresponding to the interference fringes of said exposure;
and
disposing said plurality of planar modulated index of refraction filter elements in tandem at corresponding angles to a direction of primary view through the laser protection window, the set of corresponding angles of said plurality of planar modulated index of refraction filter elements being fixed and manufactured, symmetrical with respect to the direction of primary view through the laser protection window and selected in relation to said respective blocking angles;
whereby light having an angle of incidence to the perpendicular of said laser protection window within an extended continuous angular range is within said blocking angle of at least one of said planar modulated index of refraction filter elements.

7 more elements

Dependencies are inferred from the claim text.