Browse Prior Art Database

Electron Beam Scanlaser

IP.com Disclosure Number: IPCOM000093507D
Original Publication Date: 1967-Oct-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 3 page(s) / 35K

Publishing Venue

IBM

Related People

Myers, RA: AUTHOR [+2]

Abstract

A scanlaser construction is improved by the addition of a mica, or similar material, plate. In the drawing, a CRT tube is provided with a sandwich of layers at the faceplate location. From front to back, the sandwich consists of antireflective coating 1, electro-optic crystal 2, thin optical cement coating 3, mica plate 4, dielectric mirror 5, and photoconductive layer 6 such as germanium.

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Electron Beam Scanlaser

A scanlaser construction is improved by the addition of a mica, or similar material, plate. In the drawing, a CRT tube is provided with a sandwich of layers at the faceplate location. From front to back, the sandwich consists of antireflective coating 1, electro-optic crystal 2, thin optical cement coating 3, mica plate 4, dielectric mirror 5, and photoconductive layer 6 such as germanium.

Mica plate 4 mechanically isolates the remaining elements from the inside of the CRT. Thus, it protects the CRT gun from the crystal and vice versa. Also, mirror 5 can now be supported on mica 4 instead of crystal 2, permitting the use of optical cement 3 to fill in the surface of crystal 2. The mica can provide the necessary optical bias and thus eliminate the need for the usual phase plate necessary in the scanlaser device.

Mica 4 also serves as an insulator to prevent the charge deposited on layer 6 from leaking to ground via crystal 2. This permits the charge to be stored for a much longer time period than the present 30 microseconds.

This scanlaser construction increases the decay time by a factor of fifty. A still greater increase can be obtained by increasing the thickness of layer 6. Also, mica 4 protects mirror 5 from being destroyed upon use of voltages and currents far higher than previously employed. The resolution obtained with fast sweeps is not significantly, if at all, degraded, as compared with previous devices.

As germanium is a photoconductor, the decay time can be radically increased by making use of an optical flood gun. On the other hand, for certain applications where the long storage time is not a disadvantage, mica 4 can still be used to provide...