Multi-layer holographic notch filter

• US 5,103,323 A
• Filed: 04/18/1990
• Issued: 04/07/1992
• Est. Priority Date: 04/18/1990
• Status: Expired due to Term

• Current Assignee: Holographic Optics Incorporated
• Original Assignee: Holographic Optics Incorporated
• Inventors: Cueva, John F., Magarinos, Jose R.
• Primary Examiner(s): Arnold, Bruce Y.
• Assistant Examiner(s): RYAN, JAY
• Application Number:
  US07/510,546
• Time in Patent Office: 720 Days
• Field of Search: 350/3.6, 350/3.65, 350/3.7, 350/3.77, 350/3.81, 351/44
• US Class Current: 359/8
• CPC Class Codes: A42B 3/22 Visors
• CPC Class Codes: A61F 9/022 Use of special optical filters, e.g. multiple layers, filters for protection against laser light or light from nuclear explosions, screens with different filter properties on different parts of the screen; Rotating slit-discs optical filters per se G02B5/20
• CPC Class Codes: G02B 27/0018 with means for preventing ghost images anti-reflection coatings G02B1/11
• CPC Class Codes: G02B 5/32 Holograms used as optical elements

Abstract

A holographic member for a helmet visor comprising a first holographic layer having planes of diffraction oriented in a first direction in a given local area is disclosed. A second holographic layer disposed over said first holographic layer has planes of diffraction oriented in said local area in the opposite direction. The first holographic layer is transferred from a slanted planar holographic mirror. The second holographic layer comprises the holographic analog of an oppositely slanted transferred planar mirror. The slant and the opposite slant have substantially the same magnitude of slant but opposite orientation, providing for diffractive ghost compensation. A third holographic layer, unslanted, is transferred from an unslanted planar holographic mirror. The three holographic layers provide practical total eye coverage with minimum diffractive unwanted ghosts.

Claims

1. A holographic optical element comprising a first holographic layer having planes of diffraction oriented in a first direction in a given local area and a second holographic layer disposed over said first holographic layer and having planes of diffraction oriented in said local area in the opposite direction, said first holographic layer comprising the holographic analog of a slanted mirror and said second holographic layer comprising the holographic analog of an oppositely slanted mirror, said slant and said opposite slant having substantially the same magnitude of slant but opposite orientation, said first and second holographic layers conforming to and adhered to the visor of a helmet and said slant and said opposite slant being substantially constant with respect to a tangent to the surface of said visor, said visor being disposed about a pair of eyes of a person wearing said visor, said slanted mirrors being constructed as planar mirrors, and then bent to conform to a curve disposed about said pair of eyes to act as non-planar slanted mirrors.

2. A holographic optical element comprising a first holographic layer having planes of diffraction oriented in a first direction in a given local area and a second holographic layer disposed over said first holographic layer and having planes of diffraction oriented in said local area in the opposite direction, said first holographic layer comprising the holographic analog of a slanted mirror and said second holographic layer comprising the holographic analog of an oppositely slanted mirror, said slant and said opposite slant having substantially the same magnitude of slant but opposite orientation, said holographic analogs of slanted mirrors being locally planar.

3. A holographic optical element, as in claim 2, wherein the magnitude of the slant is about 20 degrees inside each layer.

4. A holographic optical element comprising a first holographic layer having planes of diffraction oriented in a first direction in a given local area and a second holographic layer disposed over said first holographic layer and having planes of diffraction oriented in said local area in the opposite direction, said planes of diffraction in said first and second holographic layers being of substantially equal magnitude but opposite orientation in substantially all areas where said first holographic layer overlies said second holographic layer.

5. A holographic optical element comprising a first holographic layer having planes of diffraction oriented in a first direction in a given local area and a second holographic layer disposed over said first holographic layer and having planes of diffraction oriented in said local area in the opposite direction, said first holographic layer comprising the holographic analog of a slanted mirror and said second holographic layer comprising the holographic analog of an oppositely slanted mirror, said slant and said opposite slant having substantially the same magnitude of slant but opposite orientation, and a third holographic layer secured to said first and second holographic layers and defining planes of diffraction substantially parallel to the surface of said third holographic optical layer.