Abstract: Anti-veiling-glare glass input window for an optical device. The window has throughout a shallow surface layer over its peripheral surfaces radiation absorbent free-metal-induced color centers. A method for preparation of such a window, such is particularly suited to be used as an input window for an image intensifier, involves pre-shaping the window from clear glass and forming color centers in a shallow surface layer over at least the peripheral surfaces of the window. If the clear glass contains reduceable metal oxides the color centers are formed by subjecting at least the peripheral surfaces of the clear glass to a reducing atmosphere at a temperature high enough to cause the reducing atmospheres reducing component to diffuse into a shallow surface layer of the window and to reduce the metal oxides to free metal atoms.

Abstract: Anti-veiling-glare glass input window for an optical device. The window has throughout a shallow surface layer over its peripheral surfaces radiation absorbent free-metal-induced color centers. A method for preparation of such a window, which is particularly suited to be used as an input window for an image intensifier, involves preshaping the window from a clear glass and forming color centers in a shallow surface layer over at least the peripheral surfaces of the window. If the clear glass contains reduceable metal oxides the color centers are formed by subjecting at least the peripheral surfaces of the clear glass to a reducing atmosphere at a temperature high enough to cause the reducing atmospheres reducing component to diffuse into a shallow surface layer of the window and to reduce the metal oxides to free metal atoms.

Abstract: Anti-veiling-glare glass input window for an optical device. The window has throughout a shallow surface layer over its peripheral surfaces radiation absorbent free-metal-induced color centers. A method for preparation of such a window, which is particularly suited to be used as an input window for an image intensifier, involves preshaping the window from clear glass and forming color centers in a shallow surface layer over at least the peripheral surfaces of the window. If the clear glass contains reduceable metal oxides the color centers are formed by subjecting at least the peripheral surfaces of the clear glass to a reducing atmosphere at a temperature high enough to cause the reducing atmospheres reducing component to diffuse into a shallow surface layer of the window and to reduce the metal oxides to free metal atoms.

Abstract: A photocathode arrangement comprises a body of semiconductor material, such as gallium arsenide which is bonded to a fiber optic face plate. A thin anti-reflection coating of silicon nitride is positioned between the body and the plate and forms an integral part of the bond. The properties of the glasses from which the fiber optic face plate is made are carefully chosen to minimize crystal dislocations which can be introduced into the body of gallium arsenide when it is bonded to the face plate. Such crystal dislocations can seriously impair the performance of the photocathode. It has been found that it is advantageous to use a glass having an annealing temperature of about 575.degree. C. or less. Because of high temperature processing steps, its softening temperature must be about 680.degree. C. or greater. The photocathode arrangement so formed is intended to constitute the input port of an image intensifier.

Abstract: An image intensifier device is provided with color filters on its input and output surfaces so as to intensify a color image without losing the color content. Each filter consists of an array of red, green and blue elements and these elements are precisely aligned in both input and output filters to avoid degradation of the color content. A method of producing the output filter in situ is described to provide the required accuracy of alignment.