US2213796A - Gaseous electric discharge lamp device - Google Patents

Description

P 1940- 4 ZECHER El Al. 2,213,796

GASEOUS ELECTRIC DISCHARGE LAMP DEVICE Original Filed March 10, 19;?

INVENTORS Gustav Zec her Willem Ua'terhoeve BY 6 AT ORNEY Patented Sept. 3, 1940.

UNITED sTArss G ASEOUS ELECTRIC DISCHARGE LAIVIP DEVICE Gustav Zecher and Willem Uyterhoeven, Eindhoven, Netherlands, assignors to General Electric Company, a corporation of New York ApplicationgMarch 10, 1937, Serial No. 130,154.

Renewed April 5, 1939.

or boric acid. When desired, a fluorescent ma- 6 Claims.

The present invention relates to gaseous electric discharge lamp devices generally and more particularly the invention relates to such devices having a container consistirfg in whole or in part of a fluorescent] glass which transforms certain rays emitted by the gaseous electric discharge into rays of longer wave length to complement and supplement the visible light emit ted by said discharge and to increase the output of visible light from the gaseous electric discharge lamp device. The fluorescent container glass transforms certain invisible rays into visible rays and transforms certain visible rays into other visible rays to which the eye is more sensitive.

We have observed that fluorescent container glasses depreciate rapidly during-the operation of the gaseous electric discharge lamp device and that the depreciation thereof is so great as to terminate the useful life of a lamp device comprising such a container glass after a relatively short period of operation.

The object of the present invention is to provide a long lived gaseous electric discharge lamp device comprising a fluorescent glass container. Another object of the invention is to provide means for minimizing the depreciation of fluorescent glass containers for gaseous electric discharge lamp devices. A further object of the invention is to increase the output of visible light and to improve the color of the light from a gaseous electric discharge lamp. device having a container consisting in whole or in part of fluorescent glass. Still further objects 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.

We have discovered that the fluorescent container glasses are deleteriously affected by the gaseous electric discharge in said lamps which causes a rapid reduction in the fluorescent light output of such glasses and, of course, in the light output of the lamp. The invention attains its objects by covering the inner surface of the fluorescent container glass with a material which is resistant to the effects of the gaseous electric discharge and which transmits the visible light rays from the discharge and the rays which cause light emission by the fluorescent-container glass. The protective covering or coating is applied to the inner surface of the-fluorescent glass container by flowing or spraying during the manufacture of the lamp device and, preferably,

consists, in whole or in part, of. phosphoric acid In Germany March 12,

terial, such as zinc silicate, is applied in or on the protective coating which coating serves as a binder for the fluorescent material. The use of the fluorescent material in or on the protective coating is particularly advantageous because .greater luminous efficiencies and many more striking color effects are attained.

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

Fig. 2 is a pair of curves one showing raphically the light output of a gaseous electric dis.- charge lamp device embodying the invention and the other showing the light output of a similar lamp not embodying the invention;

Referring to Fig. 1 of the'drawing the gaseous electric discharge devicecomprises an elongated,

' tubular container I having electrode chambers 2 and 2 at the ends thereof and electrodes 3 and 3 sealed therein and mounted in said chambers an activating material, such as barium oxide.

Said container I has luminosity producing gaseous atmosphere therein, such as rare gas, metal vapor, or a gas and metal vapor mixture, which emits rays under excitation by the discharge between said electrodes 3 and 3 capable of causing the emission of light from fluorescent glasses. Preferably the gaseous atmosphere consists of a mixture of neon, argon and mercury vapor. The part 4 of the container I surrounding the discharge path between said electrodes 3 and. 3 consists of a boro-silicate, ultra-violet transmitting glass having metal phosphors, such as tin or copper, incorporated therein whichemit light under radiation from the gaseous electric discharge between said electrodes 3 and 3'. The inner surface of the container part4 has a. coating 5 of material, such as boric acid, which is more resistant to the eflects of the discharge than the fluorescent glass of container part 4 and which transmits the visible light and the phosphor exciting radiation emitted by the gaseous electric discharge. While the coating 5 is shown as being of substantial thickness for clarity of illustration, it will be understood that said coating 5 is preferably a thin one. Preferably the coating 5 has a fluorescent coating 6 applied thereto which coating transmits the radiations from the discharge and emits light when irradiated. The coating 5 also transmits the visible light emitted by the fluorescent coating 6. A fluorescent coating 6 of zinc silicate, which emits a whitish yellow light, is desirable.

Curve I of Fig. 2 of the drawing represents the light output of a gaseous electric discharge lamp device similar to that illustrated in Fig. 1 but not having the protective coating 5 nor the fluorescent coating 6 thereon. In plotting the curve the initial light output of the lamp was taken as 100%. As is apparent fromaan inspection of the curve I the light output of the gaseous electric discharge lamp device diminishes rapidly and is only one half its original value after the lamp has been operating only 250 hours. After the lamp has been operating 1000 hours the light output thereof is about A; of its original value. 1

Curve II of Fig. 2 represents the light output of'a gaseous electric discharge lamp device similar to: that shown in Fig. 1 of the drawing and embodying the invention. The light output of.

the lamp was measured in the same manner and the lamp was .operated under the same condi' tions as the lamp from which the values for curve I were taken. From an inspection of the curve II it is apparent that the light output of the lamp decreased at a much slower rate and that the light output thereof was more than 50%' of its original value even after the lamp had been operating 1500 hours. A gaseous electric discharge lamp device embodying the present invention not only depreciates in light output at a slower rate, as indicated by the curves I and II, but also has a greater light output, due to the fluorescent coating 5, than prior lamps in which the fluoresa cent glass of the container was exposed to the discharge and the fluorescent coating 6 was missmg.

While we have shown anddescribed 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 broad spirit and scope of the invention, for example, the container I has the shape of a symbol, or a letter useful in advertising, when desired, thermionic electrodes of the activated type are used in place of the cold electrodes 3 and 3 when desired, and said thermionic electrodes are heated to an electron emitting arc discharge supporting temperature by a separate heater current or by the discharge current flow therethroiugh and the Voltage drop thereat, when de sire What we claim as new and desire to secure by Letters Patent of the United States is:

l. A gaseous electric discharge lamp device comprising a container, electrodes sealed there'- in, a gaseous atmosphere therein rich in ultra violet rays when excited by a discharge betweensaid electrodes and a protective coating on the inner surface of said container, said container consisting of ultra violet transmitting glass having incorporated therein a material capable of light emission under excitation by radiation from the gaseous electric discharge between said electrodes, said container glass being deleteriously affected by said discharge, said coating covering the part of said container incorporating said light emitting material and consisting of a material permeable to said exciting radiation and which is capable of resistingthe effects of said discharge to reduce the depreciation of said lamp.

2. A gaseous electric discharge lamp device comprising a container, electrodes sealed therein, a gaseous atmosphere therein rich in ultra violet rays when excited by a discharge between said electrodes, a protective coating on the inner surface of said container and a quantity of fluorescent material adherent to said coating, said container consisting of ultra violet transmitting glass having incorporated therein a material capable of light emission under excitation by radiation from the gaseous, electric discharge between said electrodes, said container glass being deleteriously affected by said discharge, said coating covering said light emitting container part and consisting of a material permeable to said exciting radiation and which is capable of resisting the effects of said discharge to reduce the depreciation of said lamp.

3. A gaseous electric discharge lamp device comprising a container, electrodes sealed therein, a gaseous atmosphere therein rich in ultra violet rays when excited by a discharge between said electrodes and a protective coating on the inner surface of said container, said container consisting of ultra violet transmitting glass having incorporated therein a material capable of light emission under excitation by radiation from the gaseous electric discharge between said electrodes, said container glass being deleteriously affected by said discharge, said coating covering said light emitting container part and consisting of boric acid to reduce the depreciation of said lamp.

4. A gaseous electric discharge lamp device comprising a container, electrodes sealed therein, a gaseous atmosphere therein rich in ultra violet rays when excited by a discharge between said electrodes and a protective coating on the inner surface of said container, said container consisting of ultra violet transmitting glass having incorporated therein a material capable of light emission under excitation by radiation from the gaseous electric discharge between said electrodes, said container glass being deleteriously affected by said discharge, said coating covering said light emitting container part and consisting of phosphoric acid to reduce the depreciation of said lamp.

5. An article of manufacture consisting of a glass body having a luminescent material incorporated therein and a protective coating on said body, said glass body being deleteriously affected by a gaseous electric discharge, said coating being resistant to said discharge.

6. A gaseous electric discharge lamp device comprising a container, electrodes sealed therein, a gaseous atmosphere therein comprising mercury vapor rich in ultra violet rays when excited by a discharge between said electrodes and a protective coating on the inner surface of said container, said container consisting of ultra violet transmitting glass having incorporated. therein a material capable of light emission under excitation by radiation from the gaseous electric discharge between said electrodes, said container ILLEM UY'I'ERHOEVEN.

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