US2195517A - Gaseous electric discharge device - Google Patents

Description

April 2, 1940. o. FRITZE ET AL 2,195,517

GASEOUS ELECTRIC DISCHARGE DEVICE Filed Oct. 6, 1936 Otto Fritze lfred Ruttenauer ORNEY Patented A r. 2, 1940 UNITED STATES PATENT OFFICE Application October 6,

lin-Halensee, Germany, assignors to General Electric Company, a corporation of New York 1936, Serial No. 104,294

In Germany October 12, 1935 4 Claims.

The present invention relates to gaseous electric discharge devices generally and more particularly the invention relates to such devices having a luminescent material associated therewith to supplement and complement the light emitted by the gaseous electric discharge in the device.

In order to obtain a green colored light from a mercury vapor discharge lamp it is necessary to screen out of the light emitted by the dis-v charge those rays other than the green colored rays. Heretofore this has been accomplished by using a filter or screen in conjunction with the lamp. Of course, when such filters are used the efliciency of the lamp is reduced and in order to avoid this disadvantage resort has been had to a green fluorescing glass, such as uranium glass, which was fabricated into a lamp container, or, when a clear glass container was used, a fluorescent material emitting green colored light, for example, zinc sulphide or zinc silicate, has been associated with the lamp. While such fluorescing glass or, materials have increased the efliciency of the lampthey have not proven entirely satisfactory because they transmit a certain portion of the blue colored rays emittedby the mercury vapor discharge which, of course, is a disadvantage when a typical orpure green light is desired.

The object of the present invention is to provide a gaseous electric discharge device which emits typical green light at high efliciencies. Another object of the invention is to provide a method of making a green colored material which emits green fluorescent light. Still 'i'urther ob- .jects and advantages attaching to the device and to its use and operation will be apparent to those skilled in the art from the following particular description.

The invention attains its object by associating with the device a green colored material which emits green colored light, for example, a green colored zinc sulphide or a green colored zinc silicate coating applied to either the inner or the outer surface of the container of the device, which material not only emits green light when irradiated by the rays emanating from the discharge but also serves as a filter or screen which transmits only the green colored rays emitted by the discharge. When desired, the green colored, green fluoresclng material is placed on a support consisting of a light transmitting material, such as a clear glass support or a celluloid support associatedwith the lamp. A lamp having this structure is a highly efllcient source of typical green colored light. It will be understood, or

course, that where fluorescent material emitting rays of another color is used, such as a material emitting blue rays, the material is colored blue to screen out the light other than the blue light emitted by the discharge.

In the drawing accompanying and forming part of this specification a gaseous electric discharge lamp embodying the invention is shown in a side elevational partly sectional view.

Referring to the drawing the gaseous electric discharge lamp device comprises a tubular container I consisting of the usual container glasses, such as lead or lime glasses. Said container I has therein a starting gas, such as argon, neon,

or xenon, or a mixture of such gases, and a quantity 6 of vaporizable material, such as mercury. An electrode 4 mounted on a current lead 3 is sealed into the pinch 2. at each end of said container I. Each of said electrodes 4 consists of a pressed and sintered mixture of pulverized, high melting point metal, such as tungsten, and a material having high electron emissivity characteristics, such as barium oxide, and is heated to an electron emitting temperature by the discharge incident thereat.

The inner surface of said container I has thereon a coating 5 of fluorescent material, such as zinc sulphide or zinc silicate which emits green colored light during the operation of the lamp device. Said coating 5 is afllxed to said container I by methods now known in the art, such as by applying .a light transmitting enamel to the inner surface of the container and partly embedding particles of the fluorescent material in said enamel. While these materials are white or slightly yellow in appearance we have discovered that they can be made green in appearance to serve as 'a screen or filter for the light other than the green light emitted by said discharge by adding theretoa green coloring material, such as nickel chloride (NiClz) or nickel sulphide (NiS) This green coloring material can also be used in form of a very fine translucent layer or coating arranged with respect to the direction of rays behind the fluorescent material.

While we have shown and described and have pointed out in the annexed claims certain novel features of the invention, it will be understood that various omissions, substitutions and changes in the forms and details of the device illustrated and in its use and operation may be made by those skilled in the art without departing from the spirit and scope of the invention, for example, sheet metal electrodes which remain comparatively cool during the operation of the device are used in place of the thermionic electrodes 4, when desired, or when desired indirectly heated electrodes, such as the Hull type of electrode is used in place of said electrodes 4, or, when desired, any of the well known starting elements, such as auxiliary electrodes or electrically conducting strips, are mounted in said container.

What we claim as new and desire to secure by Letters Patent of the United States, is:

1. A gaseous electric discharge lamp device comprising an elongated, tubular container, electrodes sealed therein at the ends thereof, a gaseous atmosphere therein emissive in visible light of a plurality of wave lengths under excitation by an electric discharge between said electrodes, a coating of fluorescent material on the wall of said container surrounding the discharge path between said electrodes, said material being emissive in visible light of one of the wave lengths of the visible light emitted by the gaseous discharge and a coloring material incorporated in said fluorescent material, said coloring material being in the same spectral range as the light emitted by said fluorescent material to screen out the visible light from the discharge other than that light of a wave length emitted by said fluorescent material whereby said lamp emits light from both the gaseous electric discharge and said fluorescent material which is characteristic of said fluorescent material.

2. A gaseous electric discharge lamp device comprising an elongated, tubular container, electrodes sealed therein at the ends thereof, a gaseous atmosphere therein comprising mercury vapor, a green fluorescent coating of zinc silicate on said container surrounding the discharge path between electrodes and a green colored composition containing nickel incorporated in said zinc silicate.

3. A gaseous electric discharge lamp device comprising an elongated, tubular container, electrodes sealed therein at the ends thereof, a gaseous atmosphere therein comprising mercury vapor, a green fluorescent coating of zinc sulphide on said container surrounding the discharge path between electrodes and a green colored composition containing nickel incorporated in said zinc sulphide.

4. A gaseous electric discharge lamp device comprising an elongated, tubular container, electrodes sealed therein at the ends thereof, a quantity of mercury therein the vapor of which is emissive in visible light of a plurality of wave lengths under excitation by an electric discharge between said electrodes, a coating of fluorescent material on the wall of said container surrounding the discharge path between said electrodes, said material being emissive in visible light of one of the wave lengths of the'visible light emitted by the gaseous discharge and a coloring material incorporated in said fluorescent material, said coloring material being in the same spectral range as the light emitted by said fluorescent material to screen out the visible light from the discharge other than that light of a wave length emitted by said fluorescent material whereby said lamp emits light from both the gaseous electric discharge and said fluorescent material which is characteristic of said fluorescent material.

OTTO FRITZE. ALFRED RUTTENAUER.

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