US3043987A

US3043987A - Electric frequency controlled color phosphor screen

Info

Publication number: US3043987A
Application number: US684768A
Authority: US
Inventors: Hyman A Michlin
Original assignee: Individual
Current assignee: Individual
Priority date: 1957-09-18
Filing date: 1957-09-18
Publication date: 1962-07-10
Anticipated expiration: 1979-07-10

Description

H. A. MlCHLlN July 10, 1962 ELECTRIC FREQUENCY CONTROLLED COLOR PHOSPHOR SCREEN Filed Sept. 18. 1957 T/COLOR SIGNAL FIG. I

m R LC! M m m m SR CONVERTER SIGNA L TO \RA DIO FREQ.

CONVERTE R if r ELECTRON GUN 8\ DEFLECTING MEANS RADIATION SOURCE PIC-3.2

RADIO FREQ.-

SOURCE ELECTRIC OR RADIATiON I SOURCE I 3&4338? Patented July 10, 19%2 United States Patent Orifice 3,943,987 ELECTRIC FREQUENCY CONTROLLED EOLGR PHOSPHGR SCREEN Hyman A. Michlin, 1575 Udell St., New York, N.Y.

Filed Sept. 18, 1957, S61. No. 684,768 10 Claims. c1. 31s 2s invention relates to color phosphor screens, and particularly to electroluminescent and electrophotoluminescent different color emitting phosphor screens in which the color is selectively controlled by electric frequencies for use as information display screen.

One object of this invention is to provide method and means for controlled color emission of selected elemental areas by excitation and electric frequency control to produce color images.

Another object of this invention is to provide method and means for controlled color emission to produce color images in sequence by selected electric frequency application. V 7

Another object of this invention is to provide method and means for controlled color emission by a raster of elemental areas .of electric field modulated in intensity and frequency. 7

Another object of this invention is to provide method and means for controlled color image changes efiected in one phosphor screen by changing electric frequencies.

Other features, objects and advantages of the invention .will be apparent from the following specification, taken in connection with the accompanying drawings in which: FIGURE 1 schematically illustrates one mode of the invention; FIGURES '2 and 3 schematically illustrate 'an other mode of the invention in both front'and side views; and FIGURE 4 schematically illustrates anothermode of the invention. a

Referring to FIGURE 1, by way of example. Screen target comprises transparent conductive layer 1 electrically connected to positive potential from potential source 6,- phosphor layer 2 made up of phosphors capable of luminescing in a selective variety of colors independently of the source of excitation and under the control of electric frequencies applied in accordance with phosphors described in Patent No. 2,780,731 and schematically represented in FIGURE 2 thereof, the transparent insulation layer 3, and the anisotropic conductive layer 4. The said anisotropic conductive layer '4 is electrically connected to potential source 6 so as to maintain the potential charge on the anisotropic conductive layer 4 constant The anisotropic conductive layer is defined in this application as an arrangement of substances having the property of having an image in electron charges electri cally or electronically produced on one surface thereon and transmitting and maintaining the said image therethrough. The anisotropic conductive layerfcan be an arrangement of substances such as globules of metal on an insulative surface as in the iconoscope mosaic; such as elemental islands of conductors separated by insulation, for example, the two-sided mosaic described in Television, by Zworykin, page 302; and, such as the two-sided target made up of thin sheet of glass as described on pages 425-426 of the Proceedings Institute of Radio Eng. (1946). The characteristics noted above are known as aeolotropic or anisotropic conductivity.

The picture tube isconventional having electron beam generating, modulating and scanning means. High pres sure mercury lamp 7 irradiates the phosphor layer 2 with ultra-violet rays to excite same to photoluminescence. The source 7 can also be suitably positioned so as to scan the phosphor layer through the transparent conductive layer 1. The color picture signal representative of the resultant color of each color picture element is transmitted from source 10 to radio frequency converter 8,

which can be conventional, for example, Where the color signal varies in intensity or level of potential, then each potential level could be electronically converted by known means to radio frequencies depending on the instant intensity or potential level of the color signal. This radio frequency would then be representative of the color to be produced which impressed on an elemental area of the transparent anisotropic conductive layer 4 would impress the instant radio frequencies on a corresponding elemental area of the phosphor layer 2 so as to reproduce the color; and the signal representative of the degree of light required for the same picture element from source 9 modulates the electron beam simultaneously with the radio frequencies modulating the electron beam to thereby produce a scanning electron beam at that instant of such intensity and radio frequency impacting sequential elemental areas of the anisotropic layer 4, and so to the phosphor layer 2 so as to reproduce the color and the intensity of light emission in corresponding areas of the phosphor layer.

In operation the ultra-violet rays from source 7 excites the phosphor layer 2 to photoluminescence, and positive potential is applied to the anisotropic conductive layer 4 and higher potential is applied to the transparent conductive layer 1 from the source 6; and the instant impacting electron beam 11, modulated by color and light intensity signal from source 9, is scanned to sequentially impact elemental areas of the anisotropic conductive layer 4 so as to impress radio frequency fields in such intensities on corresponding elemental areas of the phosphor layer 2 'so as to cause colors to be emitted representative of each color picture element and to reproduce the intensities of light emissions of each color picture element; so that by synchronous modulation of the electron beam by a linear signal representative of a color picture with the systematic scanning of the electron beam the color picture is reproduced.

To describe one modification reference is made to the schematic illustration in FIGURE 1 where the direct electrical connection between the source 6 and the transparent conductive layer ,1 is omitted, and the signal to radio frequency converter 8, schematically illustrated by dash lines, is inserted in the conducting path between the potential source 6 and the transparent conductive layer 1 so that where the color signal from source 10 is representative of the field-sequential-color-system, then the radio frequencies, in accordance with the color to'be emitted from the phosphor screen, is eifected by the intensity levels of each field-sequential-colorv signal from source 10, and the radio frequencies produced therefrom modulates the. positive potential transmitted to the transparent conductivelayer 1 from source 6 to thereby control the color emission from the phosphor layer 2, while theelectron beam 11 is modulated by the light intensity signal'from source 9 to thereby reproduce the color picture.

Another example of the invention is schematically illustrated in FIGURE 4 where excitation is by ultra-violet rays from source 7, and electrical connection to the anisotropic oraeolotropic conductive layerd is omitted; and the scanning electron beam 11, modulated by light intensity signal and color signal both representative of the color picture elements of a color picture, impacts sequential elemental areas of the anisotropic conductive layer 4 to betransrnitted through elemental areas thereof to be impressed on corresponding elemental areas of the phosphor layer 2 so as to quench or control the light emitted; and, by virtue of the known property of phosphors under excitation/becoming more conductive, the electric charges on each elemental area of the anisotropic or aeolotropic conductive layer 4 isneutrali zed by transmission through the phosphor layer 2.

Referring to FIGURES :2 and 3, for purpose of example. The electroluminescent phosphor screen 13 comprises, for example, electroluminescent phosphor ZnS:Cu,Mn which is caused to progressively change its color emission from yellow to blue on being subjected to increased electric frequencies from 50 c.p.s. to 500 c.p.s., and electroluminescent phosphor ZnS:Cu,Pb which is caused to progressively change its color emission on being subjected from low to 2000 c.p.s. of electric frequencies from green towards the blue part of the spectrum. The letter T is composed of such phosphor mixtures as to emit in greenish yellow at 50 c.p.s. and bluish green at 500 c.p.s. The background 12 is of such phosphor mixture as to emit green at 50 c.p.s. and bluish green at 500 c.p.s., and sufficiently close in color to the bluish green color emitted from the letter T as to cause the letter T not to be very clearly discernible. The electric frequency source 14 can be conventional means for producing electric frequencies in changing cycles per second from 50 c.p.s. to 500 c.p.s. to thereby efiect changing color emission and thereby cause information of the letter to be rendered clearly visible at one time, and to a point of emission where it is hardly discernible at another time. The layer 15 is a metal electrode layer, the layer 1 is a transparent conductive layer, and the layer 3 is an insulation layer.

To describe an example of an operation, reference is made to FIGURES 2 and 3. The electric frequency source 13 generates electric fields varying in frequencies from 50 c.p.s. to 500 c.p.s. so as to produce a changing display of information.

The above is only by way of example and is not intended to be restrictive as many modifications can be made; for example, the phosphors in FIGURE 2 can be used in the example schematically illustrated in FIGURE 1; and the phosphors used in FIGURE 1 can be used in the example schematically illustrated in FIGURE 2.

While the present invention has been described with reference to particular embodiments thereof, it will be understood that numerous modifications may be made by those skilled in the art without actually departing from the invention. Therefore, I aim in the appended claims to cover all such equivalent variations as come within the true spirit and scope of the foregoing disclosure.

I claim:

1. The method for producing a color image in a phos phor target, elemental areas of which emitting in a desired color depending on its excitation to luminescence and on a selected frequency of electric fields impressed thereon, which comprises the step of uniformly exciting the phosphor target, an the step of systematically and se-' lectively applying a frequency varying of potential differences to each elemental area of the phosphor target to vary the. color of emission from each elemental area of the phosphor target.

2. The method for producing colors in a pattern from an intermixture of different color emitting phosphors, each different color emitting phosphor controllable in intensity a selected different frequency of electric fields to each sequential elemental area of the phosphor layer in turn so as to effect an intensity and selection of color from each sequential elemental area thereby producing the In minescent color image.

4. An apparatus for producing an electroluminescent color image comprising an envelope, means to generate, modulate and scan an electron beam therein; and a target comprising an anisotropic conductive layer, a phosphor layer and a conductor layer in the order named with the free side of the anisotropic conductive layer arranged to be impacted by said scanning electron beam; the phosphor layer having the characteristic of varying its color emission in accordance with the frequency of electric fields applied thereto; means for selectively varying the electron energy of the scanning electron beam impacting each elemental area of the anisotropic conductive layer for a successive interval of time thereby impressing an image in electric frequencies in potentials on the anisotropic con ductive layer; and means for applying a potential to the conductor layer thereby on the application of suflicient potential differences between the potentials applied to the anisotropic conductive layer and the potential applied to the conductive layer a color image is produced.

5. The apparatus of claim 4 for producing an electrophotoluminescent color image in which the phosphor layer has the characteristics of being excited to luminescence and changing its color emission in accordance with a selected frequency of electric fields applied thereto; and comprising in addition an excitation source for exciting the phosphor layer to luminescence thereby producing an electrophotoluminescent color image.

6. An apparatus for producing changing electroluminescent colors in at least one pattern comprising a phosphor layer, one conductive layer on one side and one conductive layer on the other side of the phosphor layer; the phosphors in said phosphor layer of such characteristics that a selected frequency of electric fields applied thereto will result in a selected color emission, and on varying the frequency of electric fields applied thereto will effect a varying color emission; the phosphors arranged in such intermixture as to emit in a selected color pattern; and means for applying changing frequencies of potential differences to the conductive layers thereby producing changing electroluminescence colors in at least one pattern.

7. The apparatus of claim 6 in which the phosphors can be excited to luminescence and have the same color emission control characteristics by application of different frequencies of electric fields thereto, and comprising in addition a radiant energy source for exciting the phosphor layer.

8. An apparatus for producing an electrophotoluminescent color image comprising a phosphor layer sandwiched of color emission in accordance With excitation thereof I to lurniniscence and with a selected frequency of electric fields in the radio wave spectrum applied thereto comprising selectively arranging the different color emitting phosphors in a layer to emit in at least one desired color on application of excitation energy thereto; uniformly exciting the phosphor layer; and applying an image in different frequencies of electric potential difi'erences in the radio wave spectrum to the phosphor layer thereby producing colors in a pattern.

3. The method for producing a luminescent color image from a phosphor layer the phosphors of which on excitation thereof are capable of changing color emission under control of selected frequencies of electric fields applied thereto, and the intensity of color emission depending on the potential differences applied thereto comprising uniformly exciting the phosphor layer; and systematically and simultaneously applying such potential differences and between an anisotropic conductive layer and a conductive layer, said phosphor layer after excitation to luminescence emitting in a selected color in accordance with the frequency of electric fields applied thereto; an excitation radiant energy emission source adapted to irradiate the phosphor layer to excite same to luminescence; means for applying a potential to the conductive layer; and means for applying, on the free surface of the anisotropic conductive layer, a pattern in different electric field frequen- 1 cies in potentials different from the potential applied to the conductive layer whereby producing an electro- 5 target comprising a phosphor layer sandwiched between an 2,440,301 anisotropic conductive layer and a conductive layer, said 2,446,248 phosphor layer emitting in a selected color in accordance 2,452,522 with the frequency of electric fields applied thereto; said 2,684,885 anisotropic conductive layer adapted to be impacted by 5 2,773,216 said electron image; means for applying a potential to the 2,780,731 conductive layer; and means for causing the electron 2,795,730 image to be an image in difierent frequencies of varying 2,881,353

electron energies whereby on impacting said electron energies on the anisotropi cconductive layer an image in elec- 10 tn'c potentials difierent from the potential applied to the conductive layer is 'efiected whereby producing an electroluminescent color image.

References Cited in the file of this patent UNITED STATES PATENTS 2,239,887 Ferrant Apr. 29, 1941 a 6 Sharpe Apr. 27, 1948 Shrader Aug. 3, 1948 Leverenz Oct. 26, 1948 Nakken July 27, 1954 Edmonds Dec. 4, 1956 Miller Feb. 5, 1957 From et a1 June 11, 1957 Michlin Apr. 7, 1959 OTHER REFERENCES Destriau: Electroluminescence and Related Topics, Proceedings of the I.R.E., December 1955, vol. 43, No. 12, pages 1911 to 1940.

McKenzie: Electrons at Work, Electronics, November 15 1956, vol. 29, No. 11, pages 190 and 192.