US2215440A - Gaseous discharge tube and method of producing same - Google Patents

Description

p 7, 1940. c. R. RUSE 2,215,440

1 GASEOUS DISCHARGE TUBE AND METHOD OF PRODUCING SAME Filed April 14, 1938 120 FIG: .Z. Y /9 Car/ /5. flud INVENTOR ATTORNEY Patented Sept. 17, 1940 GASEOUS DISCHARGE TUBE AND METHOD OF PRODUCING SAME Carl R. Ruse, Toledo, Ohio, assignor to Plastic Lights, Inc., Toledo, Ohio, a corporation of Ohio Application April 14, 1938, Serial No. 202,021

cation of a color characteristic is imparted when the sign becomes illuminated by the conduction 5 of electricity through a rare gas and a different colorcharacteristic is producedwhen no luminosity is present.

Anotherobject of the invention is the provision of a sign having means for giving a vis- 20 ual indication of one color characteristic and emitting when illuminated diffused light of another color characteristic.

Another object of the invention resides in the provision of a material capable of difiusing light fl'rays passing therethrough providing a uniform distribution of light without objectionable glare.

Still another object of the invention is the provision of composite translucent means comprising materials having difierent color charac- N teristics and different light transmitting values.

Another object of the invention is the provision of an electric sign wherein the envelope is of contour to give a predetermined indication and is constructed of frangible material and 88 coated with a materiai haviag light difiusing characteristics whereby when the sign isenergized the envelope visually appears to be the source of illumination.

Still another object of the invention is the Q provision of an envelope for a gas filled sign fabricated of materials having different color characteristics and different light transmitting values.

. Still another object ofthe invention is the 4' method of coating a gas filled sign so as to form a color screen which when illuminated produces a uniformly lighted area of certain color characteristics and which serves to enhance the visibility of the sign and which imparts a distinctive l0 visual indication when the luminant is not energized.

Another object of the invention includes the method of coating a gaseous discharge tube by covering the envelope with a suitable covering 86 having non-current-conducting characteristics and which has a suitable color light diffusing pigment.

The invention also contemplates a method of applying to the outer surface of a gaseous discharge tube a covering having electrical insulating properties and which is not affected by high temperatures.

Further objects and advantages are within the scope of this invention such as relate to the arrangement, operation and' function of the related elements of the structure, to various details of construction and to combinations of parts, elements per se, and to economies of manufacture and numerous other features as will be apparent from a consideration of the specification and drawing of a form of the invention, which may be preferred, in which:

Figure l is an elevational view of a sign utilizing a tubecontaining a gas which is rendered luminescent by high tension current passing through the gas within the tube;

Figure 2 is a sectionalview through a tube of the sign structure of my invention, the view being taken on the line 2--2 of Figure 1;

Figure 3 is an isometric view of a portion of a tube embodying a modified form of the invention.

In the form of the invention of Figure 1, which illustrates a typical sign utilizing gas which is rendered luminescent by the passage of electric current, the arrangement consists of 'a tube It, in the illustration the same being bent to the configuration of atypical sign formed of .the letters G and O, the connecting portion or cross-over l2 of the tube 10 and the portions of the tube I3 and M which are connected to the current supply are coated with opaque paint or suitable coating to render them substantially, non-luminescent, thus emphasizing the sign proper. The

, ends of the tube l5 and 16 contain suitable electrodes l1 and I8 which are connected to current supply wires l9 and 20, the latter being fused or sealed into the extremities of the tube.

In the fabrication of gaseous discharge tube signs, the tube or envelope is preferably made of a frangible material such as, for example, glass and especially lead glass is employed as it is not brittle and may be easily bent under the heat of a gas flame to configurations of advertising signs. The gas within the tube may be any inert gas as, for example, neon, krypton, argon, or the like, which will be renderedluminescent by the passage of high tension current through the tube which has been attributed to electronic and ionic interchange commonly identified as electronion combination or bombardm'ent.- The color characteristic of such light so given off by the gas depends upon the particular gas used in the tube. For example, neon gas emits a light having high red color characteristics, while other gases so used have different color characteristics. Signs of this character made of substantially clear'or transparent glass tubing have little or no advertising value when they are not rendered luminescent by passing current therethrough, and in order that they may have an advertising value in the day time, it is essential that they be illuminated by energizing the gas with a high tension electric current, which increases the cost of operation. I have also found that signs of this character have an attendant apparent glare or reflection, which does not render the sign distinctive and clear and greatly depreciates its visibility from a distance. I have found, that by coating the effective sign indicating portion of the tube Ill with a covering 25, which has the faculty of diffusing substantially uniformly-the light emanating from the luminescent gas, such coating having a color characteristic which imparts to the sign distinctive utility in the day time without the necessity of expenditure of current to render the sign luminescent. I have also found that a coating which will diffuse the light renders such sign more distinctive ,to a degree as such tube or envelope coated according to my invention appears to constitute a complete or enlarged source of light as compared with a transparent glass tube, which makes the sign understandably visible from a much greater distance than has been heretofore possible, as the glare normally attendant with the use of transparent glass tubing has been eliminated, and the visual appearance of the tube enlarged.

To produce a sign of the character of my invention, it is desirable to use a covering material or coating whichis substantially a non-conductor of electricity and which will satisfactorily withstand the bombardment set up by the high voltage current passing through the tube. I have found that a coating containing the following constituents has proven very satisfactory. The coating employed is preferably a synthetic resin base enamel in which the pigment consists of titanium and antimony oxide to the extent of about 25.5% by weight of the mixture, there being about twice as much titanium oxide as antimony oxide. The balance of the mixture is the vehicle of which any synthetic resin may be used in amount of 30% by weight of the mixture and a volatile thinner in an amount of about 43.6% by weight of the mixture. While I have found a coating of the above composition to be entirely satisfactory, coatings may be utilized having pigment oxides to the extent of from 20% to 30% of the composition with the balance synthetic resins and thinner. The coating may be applied bydipping the sign into the composition and either air dried or baked on under a suitable heat. This type of application I have found produces a substantially uniform coating and therefore a uniform diffusion of the colored light emanating from the luminescent gas. The coating may be applied with a brush, but great care must be taken to assure uniformity of coating to insure proper diffusion of the light.

Figure 3 illustrates a form of coating for the glass tube ID in which the coating material 25' is a suitable color bearing ceramic which may be applied in fluid form and hardened under heat. While" this. form of the invention may be slightly more expensive to manufacture, the hard ceramic material makes an exceptionally durable surface. I have found the following composition of ceramic coating, which may be baked, fired or fused to an ordinary transparent glass tube at a temperature of around 1000 F. to 1500- F., a coating which will stand severe weather conditions. Particularly because of the fusion, it forms a glazed coating which is substantially as weather resistant as the glass itself. A suitable ceramic fusible glass enamel preferably including as constituents molybdic acid, a. low lead flux, lead molybdate, and a suitable ceramic color oxide will give a very satisfactory and uniform coating. The fusible coating may be applied to the glass tubing by immersing the tubing in the ceramic composition or by spraying the composition on the tubing. This coating may be applied to inexpensive glass tubing as, for example, clear lead glass tubing in straight lengths or may be applied to such type of tubing after it is bent to a sign configuration. I have found that the glass tubing to which the ceramic coating has been applied may be heated in a suitable flame and bent to sign configuration without materially inv nous sign. The ceramic material is then applied.

to the portion of the sign which will be rendered luminous by the current conducting gas and the sign placed in a suitable oven and heated to a temperature to fuse or fire the ceramic material to the glass, a temperature of around 1000 F.

to 1500 F. for a period of about six minutes being satisfactory to form this function. The electrodes may then be sealed in the ends of the sign tube and the sign tube connected to a vacuum pump byjmeans of the tubulation coupling mentioned above, the vacuum pump operated to withdraw as much of the air from the tube as is possible with a pump. A current of high tension is then applied to the electrodes to heat the tube simultaneously with the introduction into the sign tube of the proper amount of the rare gas such as neon, helium, and the like, which is to be rendered luminous for sign purposes. This energization of the tube with current at the time the rare gas is injected is for the purpose of burning out all impurities in the tube and is often termed bombardment. The tubulation connection is then sealed off as indicated at 30 in Figure 1 of the drawing, thus completing the formation of the finished sign.

In order to provide gaseous discharge tube signs with different color characteristics, it has heretofore been the practice to use different gases. In this connection, argon gas emits a purple color, neon a red color, and helium a pinkish white color. With my invention of covering the effective sign portion of the tube with a coating, I am enabled to impart to such coating various color pigments and thus eliminate to a large degree the use of different kinds of gases when a change in color is desired.

After considerable test and experimentation, I have found that the sign produced in accordance with my present invention wherein the luminescent portion of the envelope is surrounded with a light diffusing colored covering produces a distinctive sign indication, the visibility of which far surpasses any sign produced such as, for example, those in which the rear portions of the tube are provided with reflective surfaces or partially coated with reflective material, or in which separate reflectors are used adjacent the rear of gaseous tube signs. The sign following my present invention appears to give to the eye of an observer the impression that the entire envelope is a full source of illumination and appears to glow as such, imparting a material contrast to the surrounding medium and is understandably visible from great distances.

A fairly satisfactory result of light diffusing arrangement may be secured by coating the front half or forward visualportion of the tube structure of the sign, as such partial coating has been found to give a fairly satisfactory light diffusing characteristic. It is to be understood that my invention is inclusive of a sign of this character.

By the-use of my invention, I am enabled to produce luminous gas signs wherein very inexpensive clear lead glass tubing of small diameter may be employed which is of a character readily bendable to sign configurations by unskilled workmen in a comparatively short time, and which when coated according to my invention gives the appearance of a much larger sign, and also one which is visible from comparatively great distances and which gives a day time indication without the necessity of rendering the gas luminous by the passage of current.

I have also found that it is entirely practical to apply an opaque coating of a ceramic enamel upon the cross-overs, bend-backs, or the nonindicating portion of the sign, such as shown at l2 in Figure 1 and the bend-backs or connectors l3 and M, which may also-be fired, fused or baked to the tube. This opaque coating for cross-overs and the like may be applied over the colored ceramic coating for the sign proper after such colored coating has been applied and fused.

It is apparent that within the scope of the invention, modifications and different arrange ments may be made other than is herein disclosed, and the present disclosure is illustrative merely, the invention comprehending all variations thereof.

What I claim is:

1. In combination an envelope of light transmitting lead glass; a coating of ceramic material fused to the surface of said envelope, said coating including molybdic acid and a color oxide; a source of illumination surroundedby said envelope, said coating being of light transmitting and diffusing characteristics to prevent glare when the source of illumination is rendered lumi- 2. In combination a glass envelope of light transmitting material of a contour to give a predetermined visual indication; a gas within said envelope through which an electrical discharge takes place to render said gas luminous and illuminate said envelope to emit light rays having a color characteristic; 3, ceramic coating covering the forward visual surface portion of said envelope and fused thereto, said coating including as some of its constituents molybdic acid, a low lead flux, lead molybdate and a color oxide so as to produce a different color indication when the envelope does not emit light rays.

3. A luminous gas discharge sign or the like comprising a glass tube bent into desired configuration, electrodes sealed in opposite ends of translucent, light dispersive vitreous coating the tube and gas within the tube through which electrical discharge between the electrodes may take place to render suchgas luminous, the outer-,- surface of said tube having applied thereto a firmly adherent translucent, light dispersive coating, said coating constituting a predominant, clearly defined, source of luminosity of desired color when such gas is rendered luminous by such electrical discharge and including a low lead flux, the melting point of said coating being approximately the same as the melting point of said tube.

4. A luminous gas discharge sign or the like comprising a lead glass tube bent into desired configuration, electrodes sealed in opposite ends of the tube and gas within the tube through which electrical discharge between the electrodes may take place to render such gas luminous, the outer surface of said tube having applied there to a translucent, light dispersive coating, said coating constituting a predominant, clearly de-, fined, source of luminosity of desired color when. such gas is rendered luminous by such electrical discharge, said coating also being reflective to light from an external source, in the absence'of such discharge and including a low lead flux, the melting point of said coating being approximate ly the same as the melting point of said tube.

5. A luminous gas discharge sign or the like comprising a glass tube bent into desired configuration, electrodes sealed in opposite ends of the tubeand gas within the tube through which. electrical discharge between the electrodes may" take place to render such gas luminous, the outer surface of said tube having joined thereto a mutual fusion of said coating and said surface; said coating constituting a predominant, clearly: defined, source of luminosity of desiredf coloi when such gas is rendered luminous by such 'e lectrical discharge.

6. A luminous gas discharge sign or ithelike comprising a glass tube bent into desired configuration, electrodes sealed in opposite endsv of the. itube and gas within the tube through which electrical discharge between the electrodes may take 3 v place to render such gas .luminous, the outer, surface of said tube having joined thereto a translucent, light dispersive coating of ceramic enamel constituting a predominant, clearly defined, source of luminosity of desired color when such gas is rendered luminous by such electrical discharge said coating being joined to said sur face by mutual fusion of said coating and sur-' face.

7. A luminous gas discharge sign or the like comprising a glass tube bent into desired configuration, electrodes sealed in opposite ends of the tube and gas within the tube through which electrical discharge between the electrodes may take place to render such gas luminous, the outer surface of said tube having joined thereto a translucent, light dispersive coating of ceramic enamel constituting a predominant, clearly defined, source of luminosity of desired color when such gas is rendered luminous by such electrical discharge, said coating also being reflective to light from an external source, in the absence of such discharge said coating being joined to said surface by mutual fusion of said coating and surface.

8. A luminous gas discharge-sign or the like comprising a lead glass tube bent into desired configuration, electrodes sealed in opposite ends of the tube and gas within the tube through which electrical discharge between the electrodes 76 may take place to render such gas luminous, the outer surface of said tube having applied thereto a firmly adherent translucent, light dispersive coating, said coating constituting a predominant. clearly defined, source of luminosity of desired color when such gas is rendered luminous by such electrical discharge, the color of said gas inside of said tube when rendered luminous being different from the color of said coating in the absence of such discharge and the color of said coating being difl'erent from either of said colors when the gas is rendered luminous, said coating including a low lead flux and a coloring oxide, the melting point of said coating being approximately the same.as the melting point of said tube.

9. A luminous gas discharge tube comprising a glass tube in desired configuration, electrodes sealed in opposite ends of the tube and gas within the,tube through which electrical discharge between the electrodes may render the gas luminous, the outer surface of said tube having bound thereto a translucent vitreous coating by mutual fusion on portions of the tube which are to be luminous, and an opaque vitreous coating fused on said tube at portions where luminosity is to be suppressed.

10. A luminous gas discharge tube comprising 10 a glass tube in desired configuration, electrodes sealed in opposite ends of the tube and gas within the tube through which electrical discharge between the electrodes may render the gas luminous, and an opaque ceramic enamel bound by 15 mutual fusion onto portions of said tube where luminosity is to be suppressed.

CARL R. RUSE.

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