1. A fiber optic faceplate (FOFP) comprising
a plurality of optical fibers, each including a cladding surrounding an optical fiber core, in which the optical fiber core extends between light input and output surfaces, and
the cladding including first and second portions, in which the first portion surrounds the optical fiber core adjacent to the input surface, and
the second portion surrounds the optical fiber core between one end of the first portion and the output surface,
wherein the first and second portions are of different materials,
the first and second portions include first and second cross-sectional areas, respectively, and
the first cross-sectional area has a value identical to a value of the second cross-sectional area.
2. The fiber optic faceplate of claim 1 wherein
the first portion is formed of an optically absorptive polymer.
3. The fiber optic faceplate of claim 1 wherein
the first portion extends approximately 1 to 20 microns between the input surface and the one end.
4. The fiber optic faceplate of claim 1 wherein
the fiber optic faceplate is a fiber optic cathode plate of an image intensifier tube.
5. The fiber optic faceplate of claim 1 wherein the first portion is formed of an optical absorber material including one of spin-on absorber glass, gallium arsenide (GaAs), gold, other metal, optically absorbing metal oxides, or optically absorbing polymers.
6. A limiter device used as a fiber optic faceplate (FOFP) night vision goggle for limiting laser induced damage on a vacuum side of the FOFP, the limiter device comprising
a plurality of longitudinally extending optical fibers, each bundled to each other to form a light input surface on an external side of the FOFP and a light output surface on the vacuum side of the FOFP,
the optical fibers including fiber optic cores and a glass cladding surrounding each of the cores,
wherein a portion of the glass cladding is replaced by an optical absorber material extending longitudinally away from the light input surface,
the optical absorber material and the glass cladding include first and second cross-sectional areas respectively, and
the first cross-sectional area has a value identical to a value of the second cross-sectional area.
7. The limiter device of claim 6 wherein
the optical absorber material extends longitudinally about 1-20 microns away from the light input surface.
8. The limiter device of claim 6 wherein
the optical absorber material is different from the glass cladding.
9. The limiter device of claim 6 wherein
the optical absorber material includes one of spin-on absorber glass, gallium arsenide (GaAs), gold, other metal, optically absorbing metal oxides, or optically absorbing polymers.
10. A contrast enhancer for a fiber optic imaging device comprising
a plurality of longitudinally extending optical fibers, each bundled to each other to form a light input surface and a light output surface,
the optical fibers including fiber optic cores and a glass cladding surrounding each of the cores,
wherein a portion of the glass cladding is replaced by an optical absorber material extending longitudinally away from the light input surface,
the optical absorber material and the glass cladding include first and second cross-sectional areas, respectively, and
the first cross-sectional area has a value identical to a value of the second cross-sectional area.
11. The contrast enhancer of claim 10 wherein
the optical absorber material extends longitudinally about 1-10 microns away from the light input surface.
12. The contrast enhancer of claim 10 wherein
the optical absorber material is different from the glass cladding.
13. The contrast enhancer of claim 10 wherein
the optical absorber material includes one of spin-on absorber glass, gallium arsenide (GaAs), gold, other metal, optically absorbing metal oxides, or optically absorbing polymers.
14. (canceled)
15. (canceled)
16. (canceled)
17. (canceled)
18. (canceled)
19. (canceled)
20. (canceled)
21. (canceled)
22. (canceled)
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of validating a calibration factor for a material flow, comprising the steps of:
defining at least one density at a reference temperature of said material flow;
determining a compensated line density and a line temperature of said material flow, wherein the step of determining the compensated line density includes temperature compensating a line density by determining the line density when said line temperature corresponds to said reference temperature; and
detecting an error condition, wherein the step of detecting an error condition includes comparing said compensated line density to the at least one density.
2. The method according to claim 1, wherein said at least one density includes upper and lower limits for said compensated line density.
3. The method according to claim 2, wherein said upper and lower limits are determined by determining a reference density for said material flow at said reference temperature and selecting said upper and lower limits so that the reference density is between said upper and lower limits.
4. The method according to claim 1, wherein said at least one density is a reference density for said material flow that is determined at the reference temperature.
5. The method according to claim 1, further comprising the steps of:
measuring the line pressure of said material flow;
determining a pressure compensation factor for said material flow; and
wherein the step of determining the compensated line density includes the step of compensating said temperature compensated line density using said pressure compensation factor.
6. The method according to claim 5, wherein said step of determining the pressure compensation factor includes the steps of:
determining the ratio of changes in density to changes in pressure;
determining a pressure difference between said line pressure and a reference pressure; and
multiplying said ratio by said pressure difference to obtain said pressure compensation factor.
7. The method according to claim 5, further comprises the steps of:
measuring the material composition of said material flow;
determining a material composition compensation factor for said material flow; and
wherein the step of determining the compensated line density includes the step of compensating said temperature and pressure compensated line density using said material composition compensation factor.
8. The method according to claim 1, further comprising the steps of:
measuring the material composition of said material flow;
determining a material composition compensation factor for said material flow; and
wherein the step of determining the compensated line density includes the step of compensating said temperature compensated line density using said material composition compensation factor.
9. The method according to claim 8, further comprising the steps of:
measuring the line pressure of said material flow;
determining a pressure compensation factor for said material flow; and
wherein the step of determining the compensated line density includes the step of compensating said material composition and temperature compensated line density using said pressure compensation factor.
10. A computer program product comprising computer usable medium including executable code for executing a process comprising the steps of:
defining at least one density at a reference temperature of a material flow;
determining a compensated line density and line temperature of said material flow, wherein the step of determining the compensated line density includes temperature compensating a line density by determining the line density when said line temperature corresponds to said reference temperature; and
detecting an error condition, wherein the step of detecting an error condition includes comparing said compensated line density to the at least one density.
11. The computer program product according to claim 10 wherein said at least one density includes upper and lower limits for said compensated line density.
12. The computer program product according to claim 11 wherein said upper and lower limits are determined by determining a reference density for said material flow at said reference temperature and selecting said upper and lower limits so that the reference density is between said upper and lower limits.
13. The computer program product according to claim 10 wherein said at least one density is a reference density for said material flow that is determined at the reference temperature.
14. The computer program product according to claim 10, wherein said process further comprises the steps of:
measuring the line pressure of said material flow;
determining a pressure compensation factor for said material flow; and
wherein the step of determining the compensated line density includes the step of compensating said temperature compensated line density using said pressure compensation factor.
15. The computer program product according to claim 14 wherein said pressure compensation factor is formed by the steps of:
determining the ratio of changes in density to changes in pressure;
determining a pressure difference between said line pressure and a reference pressure; and
multiplying said ratio by said pressure difference to obtain said pressure compensation factor.
16. The computer program product according to claim 14, wherein said process further comprises the steps of:
measuring the material composition of said material flow;
determining a material composition compensation factor for said material flow; and
wherein the step of determining the compensated line density includes the step of compensating said temperature and pressure compensated line density using said material composition compensation factor.
17. The computer program product according to claim 10 characterised in that said method further comprises the steps of:
measuring the material composition of said material flow;
determining a material composition compensation factor for said material flow; and
wherein the step of determining the compensated line density includes the step of compensating said temperature compensated line density said material composition compensation factor.
18. The computer program product according to claim 17, wherein said process further comprises the steps of:
measuring the line pressure of said material flow;
determining a pressure compensation factor for said material flow; and
wherein the step of determining the compensated line density includes the step of compensating said material composition and temperature compensated line density using said pressure compensation factor to derive the compensated line density that has been compensated for material composition, pressure, and temperature.
19. A method of validating a calibration factor for a material flow, comprising the steps of:
defining at least one density at a reference temperature of said material flow;
determining a compensated line density and a line temperature of said material flow, wherein the step of determining the compensated line density includes temperature compensating a line density by determining the line density when said line temperature and said reference temperature differ and compensating the determined line density for the difference between the line temperature and the reference temperature; and
detecting an error condition, wherein the step of detecting an error condition includes comparing said compensated line density to the at least one density.
20. A computer program product comprising computer usable medium including executable code for executing a process comprising the steps of:
defining at least one density at a reference temperature of a material flow;
determining a compensated line density and line temperature of said material flow, wherein the step of determining the compensated line density includes temperature compensating a line density by determining the line density when said line temperature and said reference temperature differ and compensating the determined line density for the difference between the line temperature and the reference temperature; and
detecting an error condition, wherein the step of detecting an error condition includes comparing said compensated line density to the at least one density.