Helmet mounted display having dual interchangeable optical eyepieces

Claim 2

Helmet mounted display apparatus, comprising: a helmet, adapted to be worn by an observer, having an outer surface with an opening provided in proximity to the eyes of the observer; an image source disposed on said helmet outer surface for providing images of varying luminance; relay optic means, comprising a plurality of optical components and being disposed on said helmet outer surface, for receiving said images at an entrance pupil thereof and for guiding the images along an optical path to an intermediate image focal plane located in proximity to said outer surface opening, the images in proximity to said focal plane being in the form of the images as focused at said entrance pupil, the focused images in proximity to said focal plane being a magnification of the images at said entrance pupil, said relay optic means being adapted to engage an eyepiece; and a pair of separate interchangeable eyepiece means, each of said eyepiece means having one or more optical components and being adapted to releasably engage said relay optic means, each of said eyepiece means comprising means, when engaged, for receiving the images at an input aperture thereof and for presenting, in the observer's forward field of view, the images as focused on the optical path in proximity to said focal plane.

Claim 3

The helmet mounted apparatus of claim 1, wherein said one or more optical components of a first one of said pair of separate interchangeable eyepiece means are catadioptric.

Claim 4

The helmet mounted apparatus of claim 2, wherein said catadioptric optical components include a beamsplitter component and a combiner component, said beamsplitter component and said combiner component each having the optical characteristics of partial transmission and partial reflection, said beamsplitter component disposed in the observer's forward field of view nearest to the observer to project the images at said input aperture into the observer's forward field of view, said combiner disposed to simultaneously transmit, into the observer's forward field of view, the scenic image disposed in the observer's forward field of view beyond said combiner and to reflect the images projected by said beamsplitter component into the observer's forward field of view.

Claim 5

The helmet mounted apparatus of claim 3, wherein a surface of said beamsplitter component farthest from the observer is coated with a partially reflective, partially transmissive optical coating having optical reflectivity in the range of twenty to sixty percent.

Claim 6

The helmet mounted apparatus of claim 3, wherein a surface of said combiner component nearest to the observer is coated with a partially reflective, partially transmissive optical coating having optical reflectivity in the range of twenty to sixty percent.

Claim 7

The helmet mounted apparatus of claim 3, wherein said beamsplitter component and said combiner component are each comprised of a light weight plastic material.

Claim 8

The helmet mounted apparatus of claim 1, wherein a second one of said pair of separate interchangeable eyepiece means includes an optical reflecting component disposed in the observer's forward field of view to reflect the focused images at said input aperture into the observer's forward field of view, said reflecting component being opaque to optical signals representing the external scene disposed in the observer's forward field of view beyond said reflecting component.

Claim 9

The helmet mounted apparatus of claim 1, wherein said relay optic optical components includes a plurality of lenses of different material composition disposed in proximity to one another, whereby each of said plurality of lenses reduces chromatic abberrations of the images that are guided through said lenses.

Claim 10

The helmet mounted apparatus of claim 1, wherein said relay optic optical components includes a mirror disposed to reflect the images along the optical path in the direction of said intermediate image focal plane.

Claim 11

The helmet mounted apparatus of claim 1, wherein the length of the optical path from said entrance pupil to said focal plane is in the range of 100-400 millimeters.

Claim 12

The helmet mounted apparatus of claim 1, wherein said relay optic optical components are comprised of a lightweight glass material.

Claim 13

The helmet mounted apparatus of claim 1, wherein said relay optic optical components are comprised of a lightweight plastic material.

Claim 14

Head mounted apparatus for use in a display system, comprising: helmet means, adapted to permit attachment of optical components, having an opening in proximity to the eyes of the observer; image source means, adapted to be mounted to said helmet means, for providing an image, the average brightness of said image source means being variable over a substantial range of luminance values; and optic means, adapted to be mounted to said helmet means, for presenting a virtual image of said image source means at a focus of from one meter to infinity in the observer's visual field, said optic means comprising relay segment optic means and two separate interchangeable optical eyepiece segment means, each said eyepiece means comprising an arrangement of optical components, said relay optic means comprising an arrangement of optical components common for usage with each said eyepiece means, each said eyepiece means being adapted to releasably engage said relay optic means.

Claim 15

Head mounted apparatus for use in a display system, comprising: helmet means, adapted to permit attachment of optical components, having an opening in proximity to the eyes of the observer; image source means, adapted to be mounted to said helmet means, for providing an image, the average brightness of said image source means being variable over a substantial range of luminance values; and optic means, adapted to be mounted to said helmet means, for presenting a virtual image of said image source means at a focus of from one meter to infinity in the observer's visual field, said optic means comprising relay segment optic means and two separate interchangeable optical eyepiece segment means, each said eyepiece means comprising an arrangement of optical components, said relay optic means comprising an arrangement of optical components common for usage with each said eyepiece means, each said eyepiece means being adapted to releasably engage said relay optic means.

Claim 16

The apparatus of claim 13, wherein said relay optic means comprises means for forming an intermediate real image of said image source means at a distance of up to 400 millimeters from said image source means, said intermediate real image having a magnification of from 0.5 to 4.0.

Claim 17

The apparatus of claim 14, wherein each said eyepiece means comprises means for presenting a virtual image of said intermediate real image at a focus of from one meter to infinity in the observer's forward visual field.

Claim 18

The apparatus of claim 15, wherein the optical path length of said arrangement of relay segment optical components together with said arrangement of optical components comprising either of said eyepiece means ranges up to a maximum of 400 millimeters.

Claim 19

The apparatus of claim 16, wherein a first one of said arrangements of optical components comprising a corresponding one of said eyepiece means is catadioptric, said catadioptric eyepiece comprising partially reflective, partially transmissive optical components for superimposing said virtual image in the observer's view of the external scene, said virtual image occupying a portion of the observer's visual field having a minimum subtense of 10 degrees at the observer's eye, whereby said catadioptric eyepiece is optimized for daytime luminance conditions.

Claim 20

The apparatus of claim 17, wherein said catadioptric eyepiece comprises a partially transmissive, partially reflective plane beamsplitter disposed in front of the observer's eye, and a second partially transmissive, partially reflective curved combiner optical component disposed in front of said plane beamsplitter along the observer's line of sight.

Claim 21

The apparatus of claim 18, wherein a surface of said combiner nearest to the observer's eye is coated with a partially reflective, partially transmissive optical coating having reflectivity in the range of 20-60 percent for visible light in the wavelength range of 400-700 nanometers.

Claim 22

The apparatus of claim 19, wherein a surface of said plane beamsplitter farthest from the observer's eye is coated with a partially reflective, partially transmissive optical coating having reflectivity in the range of 20-60 percent for visible light in the wavelength range of 400-700 nanometers.

Claim 23

The apparatus of claim 20, wherein a secondary surface of each of said plane beamsplitter and said combiner is coated with an antireflective optical coating for visible light in the wavelength range of 400-700 nanometers, whereby said antireflective coating reduces spurious reflections of visible light in the wavelength range of 400-700 nanometers.

Claim 24

The apparatus of claim 18, wherein said combiner comprises a lightweight glass material such as fused silica.

Claim 25

The apparatus of claim 18, wherein said plane beamsplitter comprises a lightweight glass material such as fused silica.

Claim 26

The apparatus of claim 18, wherein said combiner comprises optical plastic material such as polycarbonate or acrylic.

Claim 27

The apparatus of claim 18, wherein said plane beamsplitter comprises optical plastic material such as polycarbonate or acrylic.

Claim 28

The apparatus of claim 18, wherein said image source means includes an output image surface, said relay optic means optical components including a plurality of lenses and a plane folding mirror, said catadioptric eyepiece optical components including at least one field lens, said catadioptric eyepiece optical components together with said output image surface and said relay optic means optical components having the following optical prescription characteristics and inter-component spacing: ______________________________________ Sur- Component face Radius Curve Thick/ Type No. (mm) Type Dist (mm) Mat'l ______________________________________ Image Source 84 40.000000 CV 61.863200 AIR Lens 85 35.488000 CX 3.000000 F4 " 86 21.770000 CV 1.792300 AIR Lens 87 33.991000 CX 6.000000 SIO2 " 88 85.875000 CX 21.905600 AIR Lens 89 201.985000 CV 5.500000 SIO2 " 90 24.617000 CX 5.209200 AIR Lens 91 175.000000 CX 4.500000 SIO2 " 92 54.941000 CX 1.433000 AIR Lens 93 30.044000 CV 3.000000 F4 " 94 384.855000 CX 34.294000 AIR Mirror 95 -- -- 19.000000 AIR Lens 96 221.803000 CV 5.000000 SIO2 " 97 74.673000 CX 81.356900 AIR Lens 98 2000.000000 CX 5.000000 ACRYL " 99 221.803000 CV 33.643100 AIR Beamsplitter 100 -- -- 34.801353 AIR Combiner 101 128.165000 CV 35.941353 AIR Beamsplitter 100 -- -- 3.000000 ACRYL " 102 -- -- 51.420000 AIR " 103 -- -- -- -- ______________________________________

Claim 29

The apparatus of claim 18, wherein said image source means includes an output image surface, said relay optic means optical components including a plurality of lenses and a plane folding mirror, said catadioptric eyepiece optical components including at least one field lens, said catadioptric eyepiece optical components together with said output image surface and said relay optic means optical components having the following optical prescription characteristics and inter-component spacing: ______________________________________ Sur- Component face Radius Curve Thick/ Type No. (mm) Type Dist (mm) Mat'l ______________________________________ Image Source 84 40.000000 CV 42.360000 AIR Lens 130 149.880000 CX 3.000000 POLYC " 131 53.660000 CV 18.418400 AIR Lens 132 110.449000 CX 7.000000 ACRYL " 133 57.279000 CX 21.000000 AIR Mirror 134 -- -- 43.000000 AIR Lens 135 316.793000 CX 4.000000 ACRYL " 136 316.793000 CX 69.000000 AIR Lens 137 163.725000 CX 7.000000 ACRYL " 138 42.692000 CX 0.000000 AIR Lens 139 42.692000 CV 2.000000 POLYC " 140 135.158000 CX 130.000000 AIR Mirror 141 -- -- 76.000000 AIR Lens 142 65.596000 CV 4.200000 ACRYL " 143 55.139000 CX 64.000000 AIR Beamsplitter 144 -- -- 25.300000 AIR Combiner 145 135.158000 CV 26.500000 AIR Beamsplitter 144 -- -- 3.000000 ACRYL " 146 -- -- 47.000000 AIR " 103 -- -- -- -- ______________________________________

Claim 30

The apparatus of claim 17, wherein the effective focal length of said relay optic means optical components together with said catadioptric eyepiece optical components is the range of 15-55 millimeters.

Claim 31

The apparatus of claim 16, wherein a second one of said arrangements of opitcal components comprising a corresponding one of said eyepiece means is refractive, said refractive eyepiece comprising a totally reflective plane mirror disposed in front of the observer's eye in the observer's line of sight and at least one lens disposed between the observer's eye and said plane mirror, said plane mirror and said lens disposed to present said intermediate real image into the observer's visual field, said intermediate real image occupying a portion of the observer's visual field having a minimum subtense of 20 degrees at the observer's eye, whereby said refractive eyepiece is optimized for nighttime luminance conditions.

Claim 32

The apparatus of claim 29, wherein the effective focal length of said relay optic means optical components together with said refractive eyepiece optical components is in the range of 15-55 millimeters.

Claim 33

The apparatus of claim 29, wherein said image source means includes an output image surface, said relay optic means optical components including a plurality of lenses and a plane folding mirror, said refractive eyepiece optical components including at least one eyepiece lens, said refractive eyepiece optical components together with said output image surface and said relay optic means optical components having the following optical prescription characteristics and inter-component spacing: ______________________________________ Sur- Component face Radius Curve Thick/ Type No. (mm) Type Dist (mm) Mat'l ______________________________________ Image Source 84 40.000000 CV 61.863200 AIR Lens 85 35.488000 CX 3.000000 F4 " 86 21.770000 CV 1.792300 AIR Lens 87 33.991000 CX 6.000000 SIO2 " 88 85.875000 CX 21.905600 AIR Lens 89 201.985000 CV 5.500000 SIO2 " 90 24.617000 CX 5.209200 AIR Lens 91 175.000000 CX 4.500000 SIO2 " 92 54.941000 CX 1.433000 AIR Lens 93 30.044000 CV 3.000000 F4 " 94 384.855000 CX 34.294000 AIR Mirror 95 -- -- 19.000000 AIR Lens 96 221.803000 CV 5.000000 SIO2 " 97 74.673000 CX 93.000000 AIR Lens 112 1863.457201 CX 7.000000 ACRYL " 113 39.515000 CX 21.000000 AIR Mirror 114 -- -- 20.500000 AIR Lens 115 -- -- 4.000000 ACRYL " 116 83.478000 CX 0.500000 AIR Lens 117 39.515000 CX 4.500000 ACRYL " 118 -- -- 25.000000 AIR 103 -- -- -- -- ______________________________________

Claim 34

The apparatus of claim 29, wherein said image source means includes an output image surface, said relay optic means optical components including a plurality of lenses and a plane folding mirror, said refractive eyepiece optical components including at least one eyepiece lens, said refractive eyepiece optical components together with said output image surface and said relay optic means optical components having the following optical prescription characteristics and inter-component spacing: ______________________________________ Sur- Component face Radius Curve Thick/ Type No. (mm) Type Dist (mm) Mat'l ______________________________________ Image Source 84 40.000000 CV 42.360000 AIR Lens 130 149.880000 CX 3.000000 POLYC " 131 53.660000 CV 18.418400 AIR Lens 132 110.449000 CX 7.000000 ACRYL " 133 57.279000 CX 21.000000 AIR Mirror 134 -- -- 43.000000 AIR Lens 135 316.793000 CX 4.000000 ACRYL " 136 316.793000 CX 69.000000 AIR Lens 137 163.725000 CX 7.000000 ACRYL " 138 42.692000 CX 0.000000 AIR Lens 139 42.692000 CV 2.000000 POLYC " 140 135.158000 CX 130.000000 AIR Mirror 141 -- -- 114.000000 AIR Lens 173 84.312000 CX 8.000000 POLYC " 174 84.312000 CX 23.000000 AIR Mirror 175 -- -- 21.000000 AIR Lens 176 34.836000 CX 5.000000 ACRYL " 177 -- -- 24.000000 AIR 103 -- -- -- -- ______________________________________

Claim 35

The apparatus of claim 13, wherein said image source means comprises a miniature cathode ray tube having an active image diameter in the range of 16-25 millimeters.

Claim 36

The apparatus of claim 13, wherein said optical components comprising said relay optic means are comprised of different optical materials so as to control chromatic aberrations of visible light.

Claim 37

The apparatus of claim 34, wherein said different optical materials include fused silica glass and F4 glass.

Claim 38

The apparatus of claim 34, wherein said different optical materials include acrylic and polycarbonate.

Claim 39

The apparatus of claim 13, wherein said optical components comprising said relay optic means are disposed so as to allow said optic means to conform to the contour of said helmet means.

Claim 40

The apparatus of claim 13, wherein said optical components comprising said relay optic means are mounted in a modular assembly, said modular assembly being attached to an outer surface of said helmet means.

Claim 41

The apparatus of claim 13, wherein said optical components comprising each said eyepiece means are mounted in a goggle assembly, said goggle assembly disposed to releasably engage said relay optic means.