Abstract A light amplification device such as an image intensifier or low level sensing device is disclosed which includes a photocathode spaced from an aluminized target electrode and a microchannel plate intermediate said cathode and target. A thin non-selfsupporting substantially optically transparent layer of material of a substance and thickness so as to be essentially transparent to high energy electrons, on the order of 100 to 1,000 electron volts, and light is situated atop the front end of the microchannel plate, covering the passages therein, in order to trap ions, which otherwise would travel to the photocathode, neutral gas ions, and to absorb scattered low energy electrons generated by secondary emission at the rim portion of the individual tubes in said microchannel plate, which would otherwise travel into the microchannel plate passages and to pass any light which passes through the photocathode and transmit any light which penetrates through the photocathode. The microchannel plate is spaced by a predetermined first distance from the photocathode, with its covered end facing the photocathode, and is spaced by a second distance, larger than the first distance, from the aluminized target electrode.
An image intensifier which includes: a phosphor display screen of a predetermined area; a metal backing layer covering the rear surface of said phosphor display screen; a photocathode for emitting electrons in response to incident light; a microchannel plate type electron multiplying element located between said display screen and said photocathode, having a front input side facing said photocathode and a rear output side facing the back surface of said display screen, said electron multiplying element being spaced from said photocathode by a first predetermined distance within the range of 0.005-inches to 0.020-inches and being spaced from said display screen by a second predetermined distance greater than said first predetermined distance in the range of 0.030-inches to 0.050-inches, and a thin non-self-supporting substantially optically transparent layer of material coupled to and covering the front end of said microchannel plate, including the passages therein.
Claim 2
Dependent Claim
143 words
An image intensifier which includes: a phosphor display screen of a predetermined area; a metal backing layer covering the rear surface of said phosphor display screen; a photocathode for emitting electrons in response to incident light; a microchannel plate type electron multiplying element located between said display screen and said photocathode, having a front input side facing said photocathode and a rear output side facing the back surface of said display screen, said electron multiplying element being spaced from said photocathode by a first predetermined distance within the range of 0.005-inches to 0.020-inches and being spaced from said display screen by a second predetermined distance greater than said first predetermined distance in the range of 0.030-inches to 0.050-inches, and a thin non-self-supporting substantially optically transparent layer of material coupled to and covering the front end of said microchannel plate, including the passages therein.
Claim 3
Dependent Claim
24 words
The invention as defined in claim 1 wherein said non-self-supporting layer is of a thickness in the range of 50 A to 400 A.
Claim 4
Dependent Claim
23 words
The invention as defined in claim 2 wherein said material possesses a secondary emission characteristic of at least 3.0 measured at 400 volts.
Claim 5
Dependent Claim
21 words
The invention as defined in claim 2 wherein said material possesses a specific gravity in the range of 1.0 to 4.0.
Claim 6
Dependent Claim
14 words
The invention as defined in claim 2 wherein said material comprises the metal aluminum.
Claim 7
Dependent Claim
36 words
The invention as defined in claim 2 wherein said material consists of a member selected from the group consisting of aluminum, boron, beryllium, boron carbide, silicon oxide, silicon dioxide, magnesium oxide, magnesium fluoride, and aluminum oxide.