Oct. 11, 1932. c. 5', How]; _ 1,882,609

ELECTROLUMINOUS DISPLAY _ Filed June 8. 192a

ggza’rles S?oweINVEN TOR.

- T§LOIRNEYz I Patented Oct. 11, 1932 1,882,609

UNITED STATES PATENT OFFICE

CHARLES S. HOWE, OF LOS ANGELES', CALIFORNIA, ASSIGNOB TO LOS ANGELES TESTING LABORATORY, 01‘ LOS ANGELES, CALIFORNIA, A CORPORATION OF CALIFORNIA ELEGTBOLUMIN'OUS DISPLAY

Application ?led June 8, 1928. Serial K0. 283,883. ‘ This invention relates to improvements in at 3, and its enlar ed ends designated as 4. electro-luminous displays or signs, and refers Within the ends 0% the outer tubes are elec more particularly to concentric tubes in which trodes 5 having-wire connections 6, while the are placed gases rendered refulgent by elec electrodes 7 supply the current to the internal tricity. The invention contemplates not only tube and have wire connections 8. 50 the usual type of commercial sign, but also The electrodes are shown as wire gauze, electro-luminous displays of any character. but electrodes of any suitable type are con The invention involves the application of templated, such as cylindrical members or. the well-known principles of electricity cup-shaped members of metallic plate, in 10 demonstrated by the Geissler tube, namely, place of the wire gauze. that when an induced current is passed The internal tube 3 is sealed from the outer through a tube of transparent or translucent tube and the wire connections are likewise material-containing rare?ed vapor or gas sealed from the outer tube. forming the conductor between the poles of A Geissler tube consisting of a glass vessel 4 the inductor coil, the electrode impulses of comprisin two enlarged ends connected to the induced current produce sparks or glow gether wit a portion of smaller diameter in 60 in the tube, the color of the light varying each of which ends is enclosed an electrode, according to that of the material forming the is well known in the art. Such a tube evacu tube, to change in the current, or to a degree ated and havin introduced thereto a con of rare?cation the kind of ?uid employed. ductive gas which constitutes the sole me 63 The particular novelty in the resent in dium between the electrodes is also well vention lies primarily in the use 0 concentric known. Gases of rare, inert or monatomic tubes containing gases of di?erent or same group including , helium, , kryp characters, and these tubes hermetically and ton and xenon, have been described as gase 2.0 electrically sealed from one another so that ous mediums which on the passage of an their operation is entirely complete in itself; therethrough, each has its the arranging, however, of the tubes concen own characteristic color. trically, permits the producin of e?ects not The invention contemplated herein has to heretofore accomplis ed by t e single tubes do with the use of two or more concentrically 30 used at the present time in commercial, signs positioned tubes which are formed in any de such as the well-known neon tube sign sired con?guration with gases of different Referring to the drawing: types or same in the different tubes and op Fig. 1 represents a diagrammatic showing erated entirely separately by controlled elec of the invention. tric currents of re-determined desirable 35 Fig. 2 is an enlarged section of one end of character to illuminate or render refulgent the tube, showing the electrodes and the elec the ses in the individual tubes. The in trical connections. ' vention also contemplates the variation, ma Fig. 3 is a view taken along the line 3-—3 nipulation or control of the currents so as to ‘ofFi .2. produce continuous or intermittent changes 40 Re erring to the drawing, the intermediate in the light e?ects and color effects of the portion or portion of smaller diameter of the tubes, thereby increasing the attractiveness outer tube is designated as 1, and the enlarged and e?ectiveness of the display. ends of the outer tubes are designated as 2. All gases are electrically conductive and The intermediate tube portion of smaller' glow under the ionizing effect of the cur '45 diameter of the internal‘ tube is designated rent passing between t e electrodes. This 2 1,889,609 current may be either direct or alternating, eter throughout their length. It will be un or pulsating. The particular pressure _at derstood however that the invention is drawn which a gas is at its best conductivity varies to cover any device in which a plurality of with each gas. Speaking generally, the so tubes are used regardless of the size or con~ called active gases are most readily conduc ?guration of the passage ways through which 70 tive at a pressure in the order of {U of a the illuminated ases pass. For instance, the millimeter of . Such active gases are inner tube or t e outer tube may vary in air, nitrogen, carbon-monoxide and carbon diameter or con?guration at different points dioxide, the so-called inert gases are most to produce fantastic e?ects and increase the readily conducted at pressures of 1 milli effectiveness of the display. meter of mercury. These inert or monatomic I claim as my invention; gases are the so-called rare gases of the at 1. An illuminated display comprising in mosphere and comprises helium, argon, neon, ner and outer concentric trans arent tubes krypton and xenon. containing conductive gases and avin bulb In the case of an active gas, the conducting ular ends, and cup-shaped electr es ar 80 , pressure is fairly critical, that is to sayilea ran d within the bulbular ends of the tubes very small change in pressure above or and avin portions concentric with the tubes. low the point of maximum conduction pre 2. An i luminated display comprising in vents the tube from operating. On the other ner and outer concentric transparent tubes 20 hand, ‘in the case of inert gases, the conduct containing conductive gases and having bulb 85 ing pressures extend over a larger relative ular ends, and cup-shaped metallic gauze elec range. For example, in the case of neon, the trodes arranged within the bulbular ends of gas will conduct and glow at pressures as the tubes and having portions concentric with high as 10 millimeters or more, the minimum the tubes. > conductive pressure being somewhat below 1 CHARLES S. HOWE. millimeter. As suggested, the color of the light due to the ionization of the gas by the electric current depends upon the particular gas. In 30 a Geissler tube, for example, air glows with 95 a purple color, carbon-monoxide with a milky white, helium with a yellow color and neon with a ?ery red or oran e color. The color characteristics of the different gases are purely inherent physical properties. 100 While the difference in the color effects will normally be produced by the inherent color characteristics of the gases, itis also contem plated to produce additional color e?ects by the coloring of the tubes themselves, or by 105 adding impurities to the gases which will pro duce the desired coloration. The control and regulation of the light ef fects in the separate tubes will be manipulated ~ by an automatic or mechanically operated 110 circuit-breaking device adapted to produce the intermittent or continuous illumination of a selected tube or of the tubes in series or wave effects in the separate tubes either sin gly or in conjunction with wave e?ects pro duced in the other tubes. . It will be obvious, that innumerable com: binations of effects can be produced by manip ulation of the electric currents passing . through the gases in the separate tubes. 120 In the drawing there is shown but an inner and an outer tube, but the invention contem plates the use of a plurality of tubes contaim ing gases of different or same characters. 61) Furthermore, the control for the manipu lation of the electric currents has been elimi nated in the interest of simplicity. The speci?cations and drawing contem plate a concentric tube arrangement in which the inner and outer tubes are the same diam 130 ‘