US2302313A - Electrical discharge device, method of making, and electrode therefor - Google Patents

Description

Nov. 17, '1942. D. s. GUSTIN ELECTRICAL DISCHARGE DEVICE, METHOD OF MAKING AND ELECTRODE THEREFOR Filed March is, 1940 INVENTOR .0. G'U'fi/V.

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ATTORNEY forming said anode, and secured Patented Nov. 17, 1942 2,302,313 ELECTRICAL DISCHARGE DEVICE. Mirrnon MAKIN OF FOR G, AND ELECTRODE TRIBE- Daniel S. Gustin, Bloomfield, N. .L, assignor to Westinghouse Electric & Manufact pany, East Pittsburgh, Pa., a com Pennsylvania Comion of Application Marchlil, 1940, Serial No. 324,739 7 9 Claims.

This invention relates to discharge lamps, a method of making, and an anode particularly adapted for such lamps, and more particularly 7 to a type of lamp especially adapted for fumishing instantaneous flashes of light of high intensity which may be synchronized with the movement of an object to be photographed or of stroboscopic light, conveniently and economically manufactured, and adapted for use throughout a long life.

A feature of my invention is the provision of a discharge device in which the clean up is effected by a getter consisting of magnesium and barium, and associated with the anode.

Another feature of my invention is the employmentof a getter preferably enclosed in a cup to an anode lead.

A further feature of my invention is a degasing treatment, employed during the process of manufacture of a discharge. device, which throws off a metallic getter partially on the walls of the envelope, not only effecting clean up during exhaust, but later, after gas is introduced, the seasoning, which can be very brief, further activates the getter and effects a desirable purifying action.

A still further feature of my invention is the employment of a getter which acts during the life of the lamp to eliminate impurities evolved from the bulb walls by the action of the discharge.

Other objects and features of the invention, relating to the particular arrangement and construction of the various parts, will become apparent as the description proceeds.

Referring to the drawing illustrating my invention:

Fig. 1 is an elevational view of a discharge lamp employing my invention.

Fig. 2 is an enlarged longitudinal sectional view of the anode end portion of the lamp, with parts in elevation.

In the Blackburn application, Serial #121,383,

' filed January 21, 1937, and now U. s. Patent No.

provement on that disclosed in said Blackburn application, in that the envelope is preferably U shaped so as to concentrate the light in a smaller space while the anode is of special construction, and a novel form of getteris employed therewith, for not only effecting a quick clean up, but purifying the gas employed and serving to. increase the life of the lamp by eliminating impurities evolved during use.

Referring to the drawing in detail, there is shown a lamp ll, comprising a sealed envelope I I! of glass or other suitable vitreous material.

If it is desired to use the lamp for supplying actinic light, as for taking motion pictures, said pervlous to ultra-violet light.

The envelope I2 is desirably filled with a rare inert monatomic gas, such as neon, at a pressure of about 32 mm. of mercury, some variation, however, being permissible, say from to 32 mm. In the present embodiment it is intended that no mercury shall be included in the envelope, in order to provide for 'a more uniform'operation of the lamp.

The envelope i2 is elongated and desirably bent to U shape, as illustrated in Fig.1, in order to concentrate the light source. .sired, it may be straight, as shown in the Blackburn application referred to. The end portions are of proper sizes to contain a voltage-activated cathode IS in the end portion 13, and an anode iii in the end portion N. The portion l'l between the electrode-containing end portions is preferably so elongated and reduced in diameter as 35 shown, that the ratio between the internal diameter and the length of said attenuated portion,

within the range between A and M In one embodiment of my invention I.have secured good results by making the overall length of the attenuated portion about 9 inches, with the outside diameter of vthe restricted portion about A, thereby giving an inside diameter to said restricted portion of approximately Although the drawing is to scale to show the embodiment referred to, I do not wish to be limited to the specific dimensions which are merely illustrative.-

The cathode l5 of the tube is desirably formed cup-shaped, or as a hollow cylinder opening toward the restricted portion. It may be of nickel about .01 inch in thickness, about 2 inches long and inch in diameter. The outer end of the cylindrical portion is desirably formed by crimping about the lead-in conductor N, which may 55 be 30 mil Dumet pasing through the seal l9 to vitreous material is preferably quartz or glass However, if de- The inner surface of the cathode is desirably coated with electron emission material initially comprising the carbonates of barium and strontium, which are subsequently reduced to the oxides during the process of manufacture.

The anode it may consist of nickel, formed as a cup smaller than the cathode, and desirably opening toward the outer end of the tube. It is conveniently secured to a pair of supports 22 and 2t, desirably formed of 25 or 30 mil nickel, extending from the press 2% of a flare 25, the outer edge of which is sealed to the end of the tube, as indicated at 26. The flare is preferably provided with an exhaust tube 271 for removing the air and supplying the desired, inert gas during the process of manufacture.

The supports 22 and 23' desirably both connect with Dumet lead wires 2t and 29, which after passing through the press, may be connected together and to a brass or other suitable contact cap 3i, as illustrated.

In order to avoid the necessity, heretofore thought unavoidable, of extensive seasoning to effect a good clean-up after exhaust, heating the cathode inductively to decompose the carbonates in the usual manner, and degassing the anode in a similar fashion, I employ a getter tablet 32, desirably consisting of Kemet, which is an alloy or mixture of magnesium and barium in the proportion of 27% Ba 73% Mg. As an alternative the getter material may be held in a pair of small nickel pans telescoping with one another,

, sired manner, as by means of a wire 33 having one end welded to a support 22, and the other welded to the tablet 32.. Although spaced-from the walls of the anode, the tablet is desirably enclosed in the anode cup id, as illustrated, thereby limiting the area of the tube on which the getter material is distributed during clean up.

After the lamp has been exhausted and the gas introduced, the seasoning of said lamp may be very brief as the vaporization of the getter material during the inductive heating of the anode it, throws ofi the getter partially on the walls of the bulb, as indicated at 36, not only effecting a clean up in exhaust, and later after the gas is introduced, but this getter also acts during the life of the lamp to eliminate impurities evolved from the bulb walls by the action of the dis charge,

The lamp embodying my invention, as previously disclosed, may be used to produce continuous light when operated by a continuous current. It is, however, especially adapted to be used like the lamp of the Blackburn application referred to, that is, to produce intense flashes of light spaced at regular intervals. are possible by the use of a condenser discharge, said lamp being triggered by a grid or trigger tube in accordance with well-known practice.

- When such a lamp is used for producing intense fiashes at regular intervals,.the spectrum ofthe gas is changed from that having th characteristic lines, to that of a band superimposed on the line spectrum of the gas. If neon is the gas used, a pinkish white light may be obtained, when employed to produce spaced intense flashes. When used for the production of intense flashes Such intense flashes that modifications may be made within the spirit be of the order of thousands oi amperes rather than units, so that the electrons of the gas atoms through which the current passes, are displaced to a much greater extent than when only a small current is passed through the tube, so that movmentarily the gas is properly considered as dislines may be secured, as distinguished from the line or narrow band spectrum of the gas utilized.

Although a preferred embodiment of my invention has been disclosed, it will be understood and scope of the appended claims.

I claim:

1. A discharge lamp comprising a hollow elongated vitreous envelope, an electrode disposed in each end portion of said envelope, one of said electrodes comprising wall portions forming an I enclosure and being adapted to serve as an anode,

said electrons being adapted to function as an anode, formed hollow, and opening toward its end of the tube, and a getter tablet or capsule enclosed in said electrode but spaced from the walls thereof and consisting oi magnesium and barium.

3. A discharge lamp comprising a hollow elongated vitreous envelope, having a pair of end chambers connected by an attenuated intermediate portion, a hollow, substantially cylindrical electrode in each end chamber, said electrodes each having a diameter at least as great as the inside diameter of theattenuated portion, one of said electrodes being relatively large and oxide coated to serve as a cathode, and the other being relatively small, opeg toward its end of said envelope, containing a tablet spaced from its of light, the current during a particular flash may walls, comprising a magnesium-barium getter, and held in place by means connecting it to a supporting conductor of said anode.

4. The method of manufacturing an electric discharge device, comprising exhausting and gas filling an envelope, activating an electrode-enclosed getter consisting of magnesium and barium, while enclosed in a hollow electrode and spaced from the wall portions thereof, so that it is partially deposited on the adjacent wall portion of the envelope, to not only effect a clean-up action, but purify the gas and serve as a maintenance agent during the life of the lamp. by eliminating impurities as they are evolved, and seasoning for. only a brief period.

5. The method of manufacturing an electric discharge device, comprising placing a hollow metal cylinder in a vitreous envelope to form an electrode therein, supporting a getter consisting of metal so that it is enclosed in said cylinder but spaced from the walls thereof, exhausting and gas filling said envelope, activating said getter so that it is partially vaporized on the adjacent wall portion of the envelope, to not only effect a cleanup action, but purify the gas and serve as a maintenance agent during the life of the lamp by evolved and seasoning for only a brief period.

eliminating impurities as they are evolved, and seasoning for only a brief period.

6. The method of manufacturing an electric discharge device, comprisingv placing a hollow metal cylinder in a vitreous envelope to form an electrode therein, supporting a magnesiumbarium getter tablet so that it is enclosed-in said cylinder but spaced from the walls thereof, exhausting and gas filling said envelope, activating said tablet so that it is partially vaporized on the adjacent wall portion of the envelope, to not only efl'ect a clean-up action, but purify the gas and serve as a maintenance agent during the life of the lamp by eliminating impurities as they are 7. An electrode for a discharge device, comprising a hollow sheet metal member open at one end only; a support for said member extending into said open end, a wire extending from said support into said open end, a metal pan secured to the free end of said wire, and getter material held in said pan. I

8. The method of manufacturing an electric discharge device, comprising exhausting and gasiilling an envelope, and actuating a metallic getter in said envelope while enclosed in a hollow electrode opening toward the adjacent end of said envelope, so that the area of the envelope on which the getter material is deposited is limited to the end portion of said envelope.

9. An electrode for a discharge device comprising a hollow sheet metal member open at one end only, a support for said member, a wire extending from said support into said open end.

and getter material mounted on the free end of a said wire, enclosed in said hollow member, and spaced from the walls thereof.

, DANIEL S. GUSTIN.

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