Image intensifying device
An image intensifying device includes a lens that is positioned at a light input that forms an image of a scene. The image intensifying device also includes an image intensifier tube that includes a photocathode that is positioned to receive the image formed by the lens. The photocathode generates photoelectrons in response to the light image of the scene. The image intensifier tube also includes a microchannel plate having an input surface comprising the photocathode. The microchannel plate receives the photoelectrons generated by the photocathode and generating secondary electrons. An electron detector receives the secondary electrons generated by the microchannel plate and generates an intensified image of the scene.
1. An image intensifying device comprising:
a. a lens that is positioned at a light input, the lens forming an image of a scene;
a. an image intensifier tube comprising:
i. a photocathode that is positioned to receive the image of the scene formed by the lens, the photocathode generating photoelectrons in response to the image of the scene; and
ii. a microchannel plate comprising an input surface positioned adjacent to the photocathode and separated by a predetermined distance, and at least one of a substrate, an emissive film, and a resistive film that suppresses the generation of ions, the microchannel plate receiving the photoelectrons generated by the photocathode and generating secondary electrons; and
b. an electron detector that receives the secondary electrons generated by the microchannel plate and generates an intensified image of the scene.
2. The image intensifying device of claim 1 wherein the microchannel plate comprises a reduced lead-glass microchannel plate.
3. The image intensifying device of claim 1 wherein the microchannel plate comprises a semiconductor microchannel plate.
4. The image intensifying device of claim 1 wherein the microchannel plate substrate is formed of at least one of Al 2 O 3 , Silicon, SiO 2 , plastic, and Si 3 N 4 .
5. The image intensifying device of claim 1 wherein the microchannel plate comprises a first and a second emissive layer, the second emissive layer increasing the secondary electron emission efficiency of the microchannel plate.
6. The image intensifying device of claim 5 wherein the second emissive layer in the microchannel plate comprises at least one of Al 2 O 3 , MgO, and NiO 2 .
7. The image intensifying device of claim 5 wherein the microchannel plate further comprises an ion barrier layer that is positioned between the first and the second emissive layer.
8. The image intensifying device of claim 1 wherein the microchannel plate further comprises an ion barrier layer.
9. The image intensifying device of claim 1 wherein the microchannel plate comprises: a substrate defining a plurality of pores extending from a top surface of the substrate to a bottom surface of the substrate, the plurality of pores having a resistive material on an outer surface that forms a resistive layer; and an emissive layer formed over the resistive layer, the emissive layer being chosen to achieve at least one of an increase in secondary electron emission efficiency and a decrease in gain degradation as a function of time.
10. The image intensifying device of claim 1 wherein the microchannel plate comprises a resistive film comprising at least one of Cu 2 O, CuO, ZnO, and SnO 2 .
11. The image intensifying device of claim 1 wherein the microchannel plate comprises an emissive film comprising at least one of Al 2 O 3 , MgO, and NiO 2 .
12. The image intensifying device of claim 1 wherein the electron detector comprises at least one of a phosphor screen and a charge coupled device.
13. An image intensifying device comprising:
a. a microchannel plate having an input window for receiving an image of a scene, the microchannel plate comprising at least one of a substrate, an emissive film, and a resistive film that suppresses the generation of ions;
b. a photocathode that is positioned adjacent to the input window of the microchannel plate and separated by a vacuum gap, the photocathode generating photoelectrons in response to the received image of the scene, the microchannel plate generating secondary electrons in response to the generated photoelectrons; and
c. an electron detector that receives the secondary electrons generated by the microchannel plate and that generates an intensified image of the scene.
14. The image intensifying device of claim 13 wherein the microchannel plate comprises a reduced lead-glass microchannel plate.
15. The image intensifying device of claim 13 wherein the microchannel plate comprises a semiconductor microchannel plate.
16. The image intensifying device of claim 13 wherein the microchannel plate comprises a first and a second emissive layer, wherein the second emissive layer increases the secondary electron emission efficiency of the microchannel plate.
17. The image intensifying device of claim 16 wherein the microchannel plate further comprises an ion barrier layer that is positioned between the first and the second emissive layer.
18. The image intensifying device of claim 13 wherein the microchannel plate further comprises an ion barrier layer.
19. An image intensifying device comprising:
a. a photocathode that is formed directly on a cathode window, the photocathode generating photoelectrons in response to an image of a scene,
b. a microchannel plate having an input surface for receiving photoelectrons generated by the photocathode and being positioned adjacent to the photocathode and spaced from the photocathode by a vacuum gap, the microchannel plate comprising at least one of a substrate, an emissive film, and a resistive film that suppresses the generation of ions, the microchannel plate generating secondary electrons in response to the generated photoelectrons; and
c. an electron detector that receives the secondary electrons generated by the microchannel plate and that generates an intensified image of the scene.