US2773216A - Animated display device - Google Patents

Description

Dec. 4, 1956 T. EDMONDS ANIMATED DISPLAY DEVICE Filed Jan. 9, 1953 TO COMMUTRTOR THEoDo E EDM oNDS,

INVENTOR.

ATToRA/E United States Patent ANIIVIATED DISPLAY DEVICE Theodore Edmonds, Danvers, Mass., assignor to Sylvania Electric Products Inc., Salem, Mass., a corporation of Massachusetts Application January 9, 1953, Serial No. 330,513

11 Claims. (Cl. 315-169) This invention relates to electroluminescent display devices.

Electroluminescent lamps generally comprise a layer of electroluminescent phosphor, or of phosphor embedded in a dielectric material, between two electrodes which can be connected to an appropriate source of voltage, the layer containing the phosphor being referred to herein as a screen. One such lamp is shown, for example, in U. S. Patent 2,566,349, issued September. 4, 1951, to Eric L. Mager.

An object of the present inventionis the production of a pattern on such a screen.

Another object is to make the pattern variable, and a particular object is to make it variable in color.

In one embodiment of the invention, these results are achieved by coating a piece of so-called conducting glass with a layer of phosphor embedded in a dielectric mate rial, and making the other electrode a conductive coating over said phosphor layer and formed into the desired pattern. If the pattern contains two electrically insulated coatings, and the phosphor used is one whose color changes with frequency, such as the copper and lead activated zinc sulphide of copending application Serial No. 180,783, filed August 22, 1950, by Elmer C. Payne, then one of the coatings will luminesce one color if connected to low frequency, such as 60 cycles per second, and the other coating will luminesce another color if connected to a higher frequency, such as 500 cycles or more per second. The color of either or both coatings can be changed, for the same phosphor, by changing the frequency.

If the coating is divided into several areas, insulated from each other, then the color of any or all of the areas can be changed. For example, if the coating consists of a general background area, with several other areas spaced apart from it laterally in the form of a series of figures of some sort, then a figure can be made to seem to move from one position to another, by switching the figures in sequence from one frequency to the other.

Other objects, advantages and features of the invention will be apparent from the following specification, taken in connection with the accompanying drawings, in which Fig. l is a back view of one embodiment of the invention, showing the pattern of the coating on the back, and its connections to the power source; and Fig. 2 is a side view of the lamp of said device.

In the figures, the glass plate 1 carries the transparent conductive coating 2 of stannous chloride or the like, as is now well-known in the art, thus forming a so-called conductive glass. A coating 3 of a mixture of phosphor and dielectric material, such as shown for example in copending application Serial No. 230,596, filed June 8, 1951 by Lowry, Mager and Butler, is placed over the conductive coating 2, which is at ground potential. The metal coating 4, broken up into the areas 5, 6, 7, 8, 9, which are spaced from each other by an amount suflicient to electrically insulate them from each other by the spacing 'ice 2 shown as lines 10, -11, 12, 13, is placed over the phosphordielectric coating 3. t

In the particular embodiment shown, a copper and lead activated electroluminescent zinc sulfide is used as the phosphor, and the metal area 6 is then connected to a potential of low frequency, say cycles per second, to luminesce green, representing a grass-covered hill, for example, and the area 5 is connected to a potential of 500 cycles or higher, torepresent' the sky. The areas 7, 8 and 9 which represent a car in successive positions going down the hilland out into space, will then be connected to a potential of 60 cycles per second when the car is to be shown and to a source of 500 cycles per second when the car is not to be shown. Thus by connecting area 7 to a potential of 60 cycles per second, the pattern of a car appears in area 7 and it will not appear in the areas 8 and 9 if the latter are at that time connected to a potential of 500 cycles per second, so that areas 8 and 9 fade into the background of blue area 5. If then the area 7 is switched to 500 cycles, the car disappears there, and if the area 8 is changed to 60 cycles the car appears in area 8, as if it had moved downward from 7 to 8. By then switching area 8 to the higher frequency and 9 to the lower, the car will appear to move to position 9, as if it had jumped off the hill and out into space.

The area 6 is permanently connected to a 60-cycle source to represent the green hill, and area 5 to 500cycles to represent the blue sky. The potentials of the areas 8, 9 and 10, representing the car, are switched from one frequency to another by the commutator 14, rotated by the motor 15, thetwo being connected by the shaft 16. The commutator drum 17 is of insulating material with the metal segments 18, 19, 20, 21, 22 set therein in position to contact the brushes 23, 24, 25, connected respectively to areas 7, 8, 9 of the lamp. The segment 20 is long enough to contact both brushes 24 and 25, and segments 19 and 22 are connected together inside the drum 17. Rings 26 and 27 extend around the circumference of drum 17, ring 26 being connected to segments 19, 20 and 22, and ring 27 to segments 18 and 21. Brushes 28, 29 bear, respectively, on rings 26, 27, connecting the latter, respectively, to sources of power of 500 cycles per second and of 60 cycles per second, as shown, the other sides of the lines being grounded for convenience, or connected back to the transparent conduction coating 2. The commutator segments 18, 19, 20, 21, 22 for the first two steps of the cars progress are shown in the figure.

Although for convenience the invention has been described in connection with the particular embodiment above, its usefulness is more general, and it can be used in various places where a luminous pattern of more than one color is desired, or a pattern variable with time. The device can be used to present not only pictures, but also other information in the form of lettering, numbering or other symbols.

In the foregoing specification the frequency for the blue color has been taken as 500 cycles per second for convenience, but the light will ordinarily be much more blue it a frequency of 5000 cycles per second is used.

What I claim is:

1. An electroluminescent display device comprising a layer of electroluminescent material whose emission color varies with the frequency of the field applied thereto, at least one electrode on one side of said layer, and at least two electrodes on the other side of said layer and electrically insulated from each other.

2. The combination of claim 1, and means for supplying a potential of different frequency to each of said electrodes.

3. An electroluminescent display device comprising a layer of electroluminescent material whose emission color varies with the frequency of the applied field, at least one electrode on one side of said layer and at least two 'lec trodes on the other side of said layer and electrically in- 7. The combination of claim 6, and means for applymg a potential sequentially to some of ai coatings in the series. I

8. The combination of claim 6, means for displaying a potential to at least some of the areas, and means for changing the frequency of th potential applied to some of the areas.

9. The combination of claim 6, i n which the coatings in the series are arranged in a predetermined design.

10. An electroluminescent display devieecomprising a layer of 'copper-and-le 'ad activated 'z'in'c sulfide electroluminescent material whose emission color varies With the en at the ,fl lda pliqd th eto at. least. oae trode on one side of said layer, and at lea st two electrodes on the other side of said layer and electrically insulated from each other.

11. An electroluminescent display device comprising a er q ve le trq um ae a nt m te lrv lh e emis vefipl varies with the frequency of the field applied thereto, meansfor rnaking. electrical connection to one sidle of saidv 9i eefis d l a i t' s l c i i t a uflk a P9 vn bf theb h l d q j al, 1' l mite e sr q mf ks ifig elesti a aectiqa an th r Pqr qm Sai ethe side electrically insulated from 'said first-mentioned portion.

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