US3337683A

US3337683A - Scanning device

Info

Publication number: US3337683A
Application number: US570139A
Authority: US
Inventors: Lawrence S Sliker
Original assignee: INTERNATIONAL SCANNING DEVICES Ltd
Current assignee: INTERNATIONAL SCANNING DEVICES Ltd
Priority date: 1966-08-02
Filing date: 1966-08-02
Publication date: 1967-08-22
Anticipated expiration: 1984-08-22

Description

Aug. 22, 1967 1 s. SLIKER 3,337,683

SCANNING DEVICE Original Filed May 23, 1963 2 Sheets-Sheet l s 9o 36 38 3 a 40 54 84 N [l/111111111171111 lll/0l! i.m- N Y MWI/111110111111112 r 2s 2O 24 25 82 S FIGA INVENTOR LAWRENCE sisLlHER BY FIG 3 o ATTORN EW Aug- 22', 1967 L. s. SLIKER 3,337,683

SOANNING DEVICE Original Filed May 23, 1963 ,2 Sheetsheet 78 eo 74 7o 7 I6 83 o 27e 2o INVENTOR. LAWRENCE S. SLIHER. 300

ATTORNETl United States Patent O 3,337,683 SCANNING DEVICE Lawrence S. Sliker, Rochester, N.Y., assignor, by mesne assignments, to International Scanning Devices Limited, Chippewa, Ontario, Canada, a corporation of Canada Continuation of application Ser. No. 282,739, May 23,

1963. This application Aug. 2, 1966, Ser. No. 570,139

16 Claims. (Cl. 178-5.4)

ABSTRACT F IHE DISCLOSURE For use in television or the like, a at scanning unit utilizing crossed conductors on opposite sides of an electroluminescent layer in a scanning section, 'and a viewing section including a pair of conductive layers sandwiching therebetween a photoconductive layer, an opaque layer, and a light transducer layer with means for providing a high-frequency potential between the conductive layers, modulated in :accordance With an information signal; an improved means for sequentially energizing the conductors of the scanning array by the provision of aligned gaps and magnetic control means extending along the line of gaps to drive a spark from gap to gap and thus effect sequential energization. In addition, minute conductive elements extending through the opaque layer in the viewing section, and a color reproducing arrangement wherein the uppermost conductive layer is subdivided into strips corresponding to separate colors, with each strip associated with a color being electrically interconnected with each of the other strips of the same color association, the sets of interconnected strips being connected with the first conductive film through high frequency potential producing means modulated in accordance with the separate colors.

Detailed description This is a continuation of application Ser. No. 282,739, iiled May 23, 1963.

This invention relates to an electroluminescent display or photosensitive unit for television, radar and the like.

The display unit commonly used for television and radar is based on the conventional cathode ray tube wherein an electron beam from a hot cathode is caused to scan a fluorescent screen in order to reproduce information transmitted from a distant source. Such tubes are bulky in that considerable `depth is required to accommodate a beam of sutlicient length for deflection purposes necessary to scanning. In addition, such tubes, being evacuated, must be so shaped as to withstand atmospheric pressure particularly over its screen supporting face, necessitating an arched and generally circular configuration. Since the scanning operation is effected over .an area of rectangular shape, the circular shape cannot readily accommodate all of the information transmitted from source, unless the circular size of the screen is made oversize to circumscribe the rectangular area. Such tubes require a high potential between the cathode and screen, and sweep circuits acting through deection coils or plates to effect scanning.

The present invention lis directed to a display unit which may 'be rectangular, fiat or curved as desired :and of uniform and extremely shallow depth, and in which use of a hot cathode and beam in an evacuated envelope, as Well as beam deflection means -are completely eliminated. More particularly the present invention is directed to a at plate layer like display unit having a built in scanning section, and a luminescent display unit actuated by the scanning section, the latter having intensity modulation control means. While the invention is particularly adapted to providing a rectangular display,it may 'be modified for circular display.

3,337,683 Patented Aug. 22, 1967 The above and novel features of the invention will appear more fully hereinafter from the following detailed description when taken in conjunction with the accompanying drawings. Itis expressly understood that the drawings are employed for purposes of illustration only and are not designed as a definition of the limits of the invention, reference being had for this purpose to the appended claims.

In the drawings, cate like parts:

FIGURE 1 is a fragmentary diagrammatic section view through the electroluminescent display unit;

FIGURE 2 is a sectional View taken substantially on the line 2 2 of FIGURE l illustrating the scanning portion of the unit;

FIGURE 3 is a fragmentary diagrammatic view of a modification of the outer layers of the device;

FIGURE 4 is a fragmentary sectional view similar to FIGURE .2, showing modication of the scanning unit to produce interlaced pictures; and

FIGURE 5 is a plan diagrammatic view of a modified form wherein scanning and information control is combined.

Referring to the drawings, there is shown `a rectangular envelope formed of spaced glass plates 20` and 22, which may be peripherally sealed around the edges in any suitable manner as by fusing the glass plates together or by use of an epoxy as at 19. Disposed within the envelope is a scanning section comprising two layers 24 and 26 of parallel conductive lines, or conductors 25 and 27 respectively, arranged perpendicularly with respect to each other, and an yintervening layer of electroluminescent material 28. The layer of conductive lines 25 is supported upon the inside face of the glass plate 20, while the layer of conductive lines 27, is supported on the under face of a gl-ass plate 30. The conductive material of which the lines 27 are composed, is of transparent material such as tin oxide, SnOZ.

Above the scanning section is a light intensity control section constituting an famplier or modulating screen. For this purpose, the upper face of the glass plate 30 is provided with a coating 32 of transparent conductive material, which may likewise be of tin oxide, and the inside face of the envelope plate 22 is provided with a coating of transparent conductive lmaterial 34, which may also be of tin oxide. Disposed between the conductive layers 32 and 34, is a layer of photoconductive material 36, which may be of cadium sulphide, CdS, or the like, and a layer of electroluminescent material 38, which may be of zinc sulphide, ZnS, the layers 36 and 38 lbeing separated by a layer 40` made up of a multiplicity of minute conductive elements each surrounded by a suitable insulating material, such layer being opaque.

Referring again to the scanning section, each of the layers of parallel conductors are alike, with the exception that the conductors 25 of the lower layer 24 need not be of transparent material.

Referring to FIGURE 2 wherein the superimposed layers 24 and'26, separated by electroluminescent material 28, are illustrated, there are shown the conductors 25, of the under layer. At one end, and beyond the screen area, each conductor 25 is provided with a discharge gap 54, and the terminal ends 56 of all the conductors, are connected together as at 60, and to a common lead 62 extending through the envelope.

In a similar manner, all of the transparent conductors 27 of the upper layers are provided with a discharge gap 70. The terminal ends 72 of all of the conductors 27 are connected to a common return 76, which is in turn provided with a connecting lead 7f8 extending through the envelope. Adjacent to one of the end discharge gaps 54, is a triggering discharge gap 58, connected to the lead 60, and to lead 64 extending lthrough the envelope. In

wherein like reference characters indi- 3 the same manner, a triggering discharge gap 74 is provided adjacent to one of the end discharge gaps 70, and is connected to the common return 76, and a lead 80 extending through the envelope.

Magnetic fields, which may be produced :by any suitable means, are established along the line of the gaps 70. Each magnetic eld, which is perpendicular to the plane of the conductors 25 and 27, may be of uniform intensity along the entire line of each row of gaps, and may com-prise a pair of pole pieces. The magnetic field along gaps 54 may comprise pole pieces 82 and 84 disposed along the underside of the plate and the upper side of plate 22, in alignment with the gaps 54, as indicated `in FIGURE 1. The pole pieces may be connected by a yoke 86, extending around the peripheral edge adjacent the gaps 54. A second magnetic field is established along the line of gaps '70, in a similar fashion -by pole pieces 88 and 90. The pole pieces may be bars of permanently magnetized material, or may be of iron, magnetized by the yoke, which may be a permanent magnet, or magnetized by a magnetizing coil. The fields may also be produced 'by other suitable means such as elongated coils energized by direct current, and disposed below (and above if desired) and in alignment with the series of gaps 70. Such coils may be disposed within the envelope adjacent the gaps and may have field concentrating cores. The magnetic field of the vertical scanning, between pole pieces 82 and 84, may be caused to pulse to control the movement of the discharge from one gap to the next, in a precise manner. Thus when a magnetizing coil is used, to produce the field, the direct current potential applied to the coil is momentarily increased, or pulsed, to cause the discharge to move to the next gap.

The envelope will be filled with an inert gas under suitable pressure to permit an ionized glow discharge across the gaps 54 and 70 and triggering gaps 58 and 74, upon application of predetermined potentials thereacross.

Assuming lead 62 is connected to the positive terminal of a source of direct current potential, and lead 78 is connected to the negative terminal, and the potential is just under the value requisite to break down any one of the gaps 54, and any one of the gaps 70, no current flows, between any of the conductors 25, and conductors 27 through the conductive electroluminescent layer 28. Should there be a simultaneous discharge or breakdown across gap 70A and gap 54A, for example, a circuit is completed, see FIGURE 2, from conductor A to conductor 27A at L across the electroluminescent material 28, and luminescense would occur at L.

With such potential applied to the terminals 62 and 78, triggering potentials are simultaneously applied to the leads 64 and 80. A negative triggering potential is momentarily applied to the lead 64, sufficient to discharge at the gap at 58, thereby ionizing the gas in the immediate vicinity thereof. At the same time a positive triggering potential is applied to lead `80, sufiicient to discharge and ionize the gas in the region of gap 74.

Under the influence of the magnetic fields associated with the respective gaps 58 and 54, and gaps 74 and 70, the discharge across the triggering Vgaps 58 and 74 are caused to arc of warp toward the immediately adjacent gaps 54 and 70 respectively, ionizing the gas in the region thereof whereupon discharge across such gaps takes place, causing luminescence t0 occur initially at I due to the circuit completed across the electroluminescent material at the cross over point of the conductors 25 and 27 at I. The magnetic field tends to wa-rp lthe discharge in the gaps 54 and 70 away from the triggering gaps 58 and 74, and into the region of the immediately adjacent or second `gap 70. By providing a relatively strong magnetic field between poles 90 and 88 the triggering discharge may 'be transferred to the gaps 70, and the discharge caused to advance from gap to gap from left to right, while discharge at the initial gap 54 continues, thus causing the luminescent spot I to move along conductor 25 from left to right. The magnetic field strength between pole pieces 84 and 82 is such as to cause the discharge triggered in the first gap 54 to also travel from gap to gap from top to bottom, but at a rate such that the discharge travel from one gap 54 to the next gap occurs in the time interval required for the discharge across gaps 70 to travel the entire sequence. Thus the luminescent spot I travels from left to `right along the initial conductor 25, before the discharge across the initial gap 54 ionizes the gas sufficiently in the vicinity of the adjacent gap 54 to effect discharge. When the discharge across the sequence of gaps 70 reaches the right end gap, the arcing effect due to the magnetic field terminates the discharge. A second triggering impulse is then impressed on lead which initiates a second travelling discharge across gaps 70, and since the discharge across the initial gap 54 has moved to the next gap 54, the luminescent spot travels from left to right along the Second conductor 25. Similarly when the luminescent `spot has travelled the length of the second conductor 25, the discharge in the right hand end gap 70 is extinguished, and a third triggering potential is applied at gap 74 to initiate a third sequential discharge across gaps 70, after the discharge at the second gap 54 has moved on to the third gap 54. Thus the spot of luminescence is caused to scan along the successive lines 25, one at a time from top to bottom. When the discharge across gaps 54 reaches the lower end gap 54, it is extinguished and a triggering impulse is then applied to gap 58 togther with a succession of triggering impulses applied to gap 74 to provide a second complete scanning.

While only a small number of horizontal and vertical conductors 25 and 27 have been shown in FIGURE 2, for illustrative purposes, in scanning for television with no inter-lacing, 263 horizontal lines would be employed, while there would be approximately 350 vertical lines. Thus for 30 pictures per second, gap 58 would be triggered `60 times per second while gap 74 would be triggered 15,750 times per second.

The conductive plates 32 and 34 are connected to a source of high frequency potential, in the order of 18 megacycles or greater, the amplitude of which is varied in accordance with the modulation of the informationcontaining signal, which signal may also contain the triggering pulses applied periodically to leads 64 and 80. The luminescence of screen 28 at the scanning point renders the photoconductive plate conductive immediately adjacent the scanning point, and a condutive path between plates 32 and 34 is thereby effected through the conductive plate, one of the minute isolated conductive elements 39 in the opaque screen 40, and the electroluminescent layer 38. Since the high frequency potential applied to plates 32 and 34 is modulated by the signal strength, the degree of luminescence effected in layer 38 varies in accordance with the modulated potential applied to plates 32 and 34. It will be understood that the brilliance of the scanning trace in layer 28 will be constant, and that its effect on the conductance of the photoconductive plate will be uniform, and thus the degree of luminescence in plate 38 will vary with the signal modulation of the high frequency potential applied to the plates 32 and 34. Since the conductive plate 34 is of a transparent substance such as tin oxide, the modulaetd luminescence visually reproduces the picture or other information carried by the modulated high frequency potential applied to plates 32 and 34, the luminescence of the trace in plate 28 being hidden by the opaque plate 40. The minute conductive elements 39 of plate 40 serve to concentrate the conductive path of current flow between the plates 32 and 34, it being understood that such path continuously moves with the scanning trace.

By subsituting for the conductive plate 34, a plate having a series of separate parallel conductors, two for each scanning line conductor 25, to provide two sets of intermes-hing conductors, and by subdividing the adjacent electroluminescent layer 38 with a number of strips corresponding to the number of parallel conductors of plate 34, with each strip in registry with a corresponding pairallel conductor of plate 34, and with the strips alternating in color luminescence, so that alternate strips are luminescent in one color, and the remaining strips luminescent of a second color of two colors capable of producing full color pictures, a full color picture can be produced by applying separate high frequeny information modulated voltages between each set of the conductois and the conductive plate 32.

As illustrated in FIGURE 3 the conductive plate 34 is subdivided by a series of transparent conductive lines, 100 connected together as at 101, and a second set of conductive lines 102 connected together as at 103. The electroluminescent layer 380 is subdivided into sections 104 in registry with conductive lines 100, and alternate sections 106 in registry with conductive lines 102. The sections 104 luminesce in one color, while the sections 106 luminesce in another color, the two colors being chosen to take yadvantage of the Land system of producing full color pictures from two colors. Each of adjacent conductive lines 100 and 102 will be in registry with a scanning conductive line 25. The high frequency potential modulated in accordance with one color is connected to the lead 101 and plate 32, while the second high frequency potential modulated in accordance with the second color is connected to the .lead 103 and plate 32. For employing conductive material for the lines 100 which is semitransparent and transmits one band of color, and conductive material for the lines 102 which is sernitransparent and transmits a different band of color, of a two color system, the luminescent screen 38 need not be divided into sections, but may be continuous iand generate white light. Thus 'by energizing the lines 100 and 102 by the color con- Itrol signals, a color picture is produced.

The apparatus may be modified so as to operate for television camera use by the substitution of a photoconductive layer for the electroluminescent layer 38 shown in FIGURE 1. Thus as a picture or other information is projected upon the photoconductive layer thus substituted for the electrol'uminescent layer 38, through the transparent conductive layer 34, the conductance between the conductive layers 34 and 32 will vary in accordance with the light intensity at any point in plate 38 coextensive with the photoconductivity in the plate 36 produced by the scanning luminescent spot in electroluminescent layer 28.

By further modification the apparatus may operate as a television camera responsive to color. For this purpose the conductive plate 34 is subdivided in the manner illustrated 'in FIGURE 3, employing conductive semi-transparent light filtering materials, the conductors 100 being, for example, capable of transmitting one color, while the conductors 102 transmit a second color, or a two color Land system. With layer 38 photoconductive and segmented with a separate segment unde-r each conductor, with segments insulated from one another, and with each pair of con'ductors 100 and 102 in registry with a trace conductor 25, it will be seen that during any trace the conductance of the photoconductive layer will respond to the color intensity falling thereon through the light filter conductors 100 and 102. Thus the conductance between plate 32` and conductive lines 100 and lead 101, and the conductance between plate 32 and conductive lines 102 and lead 103 will be made to vary in accordance with the intensity of the two colors at any point corresponding to the scanning trace, the conductive path between conductors 100 and plate 32, and conductors 102 and plate 32, being concentrated by the minute conductive elements 39 in the opaque plate 40. Thus the varying conductances between plate 32, and leads 101 on the one hand and lead 103 on the other hand, may be employed `to modulate the carrier frequencies for transmission of the color information received by the camera as scanned.

It will be understood that any space between the adjacent conductors Iand 102 will be opaque to prevent light entering the photoconductive layer except through the filters. In practice the photoconductive layer, segmented` as above set forth, may have each of its segments subdivided to provide a checkerboard effect, with each individual subdivisions insulated from one another. In such case, the opaque layer 40 may be eliminated.

While a two color system has been referred to for illustration, it will of course appear that by subdividing the conductive film 34 in groups of three, and by subdividing the layer 38 accordin-gly, a three color system, both for producing pictures, or providing a camera receptive to three colors may `be had.

In FIGURE 4, there is shown a schematic view of an upper fragment of the scanning section adapted for interlacing wherein the vertical conductors, and their respective gaps 70 and triggering gap 74 and magnetic field, are the same as in FIGURES 1 and. 2. The horizontal conductors with their gaps 154, adapted to be periodically triggered by the gap 158, alternate with conductors 124 having gaps 153 tri-ggered by a gap 157. It will be seen that the direction 4of the magnetic flux across the gaps 158 and 154 will `be opposite to the direction of the flux in gaps 157 and 153 since the sequential discharge in gaps 154 by gap 158 and the sequential discharge across gaps 153, triggered by the gap 157, will both travel downwardly, and since current flow across gap 154 will be from right to left, whereas current flow in gap 153 is from left to right, the `gaps 153 having been disposed along the opposite edge, to facilitate construction. In operation, the action diifers from that heretofore set forth, in that tors 124. Thus if a complete scanning of the Ione section is. effected in 1/60 of a second followed `by a complete scanning of the other section 1/60 of a second, two interlaced pictures will be produced each 1/30 `'of a second. For standard broadcast, any number of conductive lines 27 may be employed, such as 700, Whereas the total number of conductive lines 125 and 124 may be 525..

any one of gaps 254 during discharge. Similarly `the opposite or right hand ends of the conductors 224 are offset around the area of gaps 254 and each connected to a common return 263 through a resistance 262 of the same value as the resistance of gaps 253 during discharge.

The vertical conductors may be arranged in two sets of conductors 227 and 226, for color picture pnoduction, with gaps 270 and 269 at their respective ends, triggered Aby gaps 274 and 273 respectively. The conductors 227, at their opposite ends are oifset to clear the gaps 269, and are each connected through a resistor 280 to a common return 281, and the conductors 226, at their ends opposite from their gaps 269 are offset to clear gaps 270, and are in turn each connected through a resistor 283 t-o a common return 232. The resistors 280 and 283 have the same value as the resistance of their respective gaps during discharge.

By applying direct current potentials between terminals 261 and 162 and terminal 281 and 276 of equal values and providing means for maintainng the potentials at the terminals 281 and 162, at a predetermined value with reference to ground, `with the potential at terminals 261 and 276 also at a predetermined potential with reference to ground, it will be seenn that as the discharge travels the sequence of gaps 270, the corresponding conductors 227 will be sequentially brought to a mid potential half way between the potential applied at 281 and 276. Also as dischar-ge across any one of gaps 254 takes place the corre sponding conductor 225 will be `brought to the same mid potential. Thus the voltage impressed upon the electroluminescent material between the conductors 225 and 227 at any point where a discharge energized conductor 225 `crosses a discharge energized conductor 227, both of which conductors are a mid potential due to simultaneous dis- `charge in their respective gaps 254 and 270, will be zero. Thus scanning is effected without creating any electroluminescence in the layer 28. By impressing upon terminals 276 and 162 a high frequency signal, amplitude modulated in accordance with picture information, the electroluminescent lmaterial may be caused to luminesce, with brightness in accordance with the modulated amplitude of the high frequency potential impressed across the teryminals 276 and 162. Such modulated signal frequency may be impressed upon the terminals 276 and 162 by inductively coupling the modulated signal frequency as at 290 with an inductance 292 `connected through capacitances 294 and 296 to the terminals 276 and 162. Thus the luminescent material is scanned as a dark spot by the discharge sequences occurring in gaps 270 and gaps 254, and luminescence in varying degree will only be effected at the otherwise dark spot scanned by response of the luminescent material to the amplitude of the signal frequency.

The above description, for illustrative purposes, has been made to scanning as between conductive lines 227 and 225 as though conductive lines 226 and 224 were non-existent, and such Aoperation will produce a black and white picture, viewable from either side, if the conductive lines 227 and 225 are both of transparent conductive lines 227 and 225 are both of transparent conductive material, such as tin oxide. However in practice, viewing would be from one side only such as through the lines 227, since from the other side a reflective, in effect, reverse image would be produced. In order t provide picture interlacing, scanning is effected first by employing a combination of conductive lines 224, the incoming signal frequency being impressed u-pon conductor 265, through the additional capacitance 297. Thus interlacing is effected, as will be understood from a consideration of the description in conjunction with FIGURE 4. It will be understood that the same potential is applied across leads 265 and 263, as was applied across leads 162 and 261 to ground, so that zero voltage scanning results from either set of conductors 225 and 224, in reference to conductors 227.

Color picture utilizing, for example, the two color Land system referred to, may be effected by utilizing two sets of vertical conductors, one set being conductors 227, and the other set being conductors 226. The conductors 227 will be adapted to transmit light of one color of the system, while the conductors 226 will transmit the other color. The same discharge potential as is applied across leads 276 and 281 will be applied across leads 275 and 282 having the same reference to ground, so as to produce zero potential scanning. A carrier frequency, modulated by one color band of information, will be impressed upon inductance 292, by inductance 290, to produce luminescence as between conductors 227 and 225 and 224. A second carrier frequency, modulated by the other color band of information will be impressed upon inductance 302, by inductance 300, and will produce luminescence as between conductors 226, and 225 and 224, the inductance 302 be- 8 ing suitably coupled to conductors 265, 162, and 275, through suitable capacitors 304, 306 and 308 respectively.

The same scanning section illustrated in FIGURE 5 becomes a camera upon substituting a photoconductive layer, for the electroluminescent layer 28. The photoconductive material may be cadmium sulphide. For black and white, camera operation, conductors 227 will be transparent. For color, using the two color system referred to, the conductors 227 and the conductors 226 will be of light filtering material. The conductors 227 will transmit to the photoconductive material 28 one color band, while the conductor 226 will transmit to the photoconductive layer the second band. Thus as an im-age is projected upon the layers of conductors 227 and 226, during scanning, the conductivity of the layer 28 will vary due to the light intensity impressed thereon. The variation in conductance in the photoconductive layer during such scanning may be readily used to modulate a carrier frequency. Instead of the conductors 225 and 224, and the conductors 227 and 226 being brought to the same potential by gap discharge, so that zero potential scanning is effected, a resistor is inserted in each of leads 316 and 318, so that on discharge at a gap such as 270, or 269, the potential of the corresponding conductor 227 or 226 will be at a different voltage level from the particular conductor 225 or 224 at which discharge is taking place, so that there is current iiow, through the photoconductive layer, varying with the conductance thereof at the scanning point. This variable conductance effects a varying voltage drop across each of the resistors inserted in the respective leads 316 and 318 each of which may be employed to modulate two carrier frequencies respectively to transmit color image information.

It will be understood, as before, that the conductors 227 and 226 which act as color band filters will be the only means by which light may reach the photoconductive layer, and will constitute a plane upon which information in the form of pictures, diagrams, written material or the like Will be projected as an image.

As before, the number of sets of conductive lines such as 227 and 226 may be increased from two to three to utilize a three color picture-producing or camera scanning apparatus, as will be readily understood. It will be further understood that the rate of discharge travel from left to right along gaps 270 and gaps 269 will be at the same rate of speed, and that both sets of gaps may be triggered by discharges at gaps 274 and 273, substantially simultaneously, with discharge at gap 273 following discharge at gap 274 by an interval of time no longer than one half the time for the discharge to move from one gap 270 to the next.

While scanning has been described as being effected as unidirectional, that is in one direction horizontally and one direction vertically, it will be understood that bidirectional scanning either horizontally or vertically or both could be employed using the inventive concepts herein set forth. This may be accomplished by periodically reversing the field. If the period of reversal be within the travel time of the discharge through the row of gaps, the discharge may be maintained without triggering, and triggering could be effected anywhere along the line of gaps, for starting purposes. Thus if the field varies sinusoidally the velocity of discharge travel can be made to vary sinusoidally.

It will be apparent to those skilled in the art that the invention may be employed by arranging the conductors in a polar coordinate fashion, utilizing a plurality of concentric circular conductors of gradually increasing radius, in combination with a plurality of radial conductors angularly spaced in a uniform manner, the circular and radial conductor being spaced by a layer of electricallight transducer material, that is photoconductive or electroluminescent material as set forth. The radial conductors would preferably have at their peripheral ends a gap, to produce a circumferential series of gaps, so that the discharge may travel from gap to gap circumferentially. A triggering gap may be used to initiate circumferential discharge, and may be employed to control the period for each 360 of travel. Control may be effected by pulsing the magnetic field which will be associated with the gaps to produce circumferential travel.

The circular conductors may each have a lead extending away from the plane of the conductors and each lead will have a gap, and the gaps will be arranged in a row with uniform spacing and in a suitable magnetic field. As herein referred to, a triggering gap will be provided adjacent an end gap to initiate each travel of the discharge along the row of gaps.

The term electrical-light transducer as used herein is intended to include electroluminescent material as well as photoconductive material.

Although a single embodiment of the invention has been illustrated and described with variations, it is to be understood that the invention is not limited thereto. As various changes in the construction and arrangement may be made without departing fro-m the spirit of the invention, as will be apparent to those skilled in the art, reference will be had to the appended claims for a definition of the limits of the invention.

What is claimed is:

1. A scanning tube, comprising a plurality of parallel layers including, successively, a first layer containing a plurality of spaced first conductors, a second layer of electroluminescent material, a third layer containing a plurality of spaced second conductors, a fourth layer of transparent insulating material, a fifth layer comprising a first transparent conductive film, a sixth layer comprising a photoelectric material, an opaque seventh layer comprising insulating material containing a multiplicity of minute conductive elements insulated one from another, an eighth layer comprising an electrical light transducer material, and a ninth layer comprising a second transparent conductive film, a substantial number of said first conductors overlapping in a predetermined angular relationship a substantial number of said second conductors to provide a scanning area, each of said first and second conductors containing a gap outside of said overlapping area, the gaps of said first and second conductors being disposed in rows extending transversely of said conductors, respectively, first and second common terminal means connecting the ends of said first and second conductors, respectively, beyond the respective gaps, first and second triggering conductor means connected with said first and second common terminals, respectively, each of said triggering conductor means containing a triggering gap disposed adjacent to a gap of said first and second conductors, respectively, an impervious envelope enclosing all of the gaps and containing an ionizable media; means for applying a direct current potential across the first and second common terminals of a value slightly less than that required to create discharge in the gaps of the conductors connected thereto except upon the ionization of the media in the immediate region of and from an established discharge in an adjacent gap, means for periodically applying to said first and second triggering conductor means potentials for creating triggering discharges at said triggering gaps, respectivey, and magnetic control means extending along the lines of the respective gaps for causing a discharge established in each triggering gap to move transversely and sequentially from gap to gap.

2. Apparatus as defined in claim 1, and further including means for applying across said first and second conductive films a high frequency information modulated signal potential.

3. Apparatus as defined in claim 1 wherein said eighth layer of electrical light transducer material comprises an electroluminescent material.

4. Apparatus as dened in claim 1 wherein said eighth layer of electrical light transducer material comprises a photoconductive material.

5. Apparatus as defined in claim 4, and further including means for projecting upon said eighth layer of photoconductive electrical light transducer material an image having varying light intensities.

6. Apparatus as in claim 1 wherein the sequential rate of energization of conductors of one layer is a multiple of the sequential rate of energization ofthe conductors of the other of said layers. i

7. Apparatus as defined in claim l wherein said control means causes a higher rate of movement of the discharge between the gaps of said second conductors than the rate of discharge movement between the gaps of said first conductors.

8. Apparatus as defined in claim 1 and further including third and fourth common terminal means, and a plurality of like resistors connecting the other ends of said first and second conductors with said third and fourth common terminal means, respectively, the resistance value of said resistors substantially matching the resistance of the associated gap during the discharge thereof, whereby any conductor during discharge at the gap associated therewith is substantially at mid-potential of the direct current voltage source to effect substantially zero potential scanning of the electrical transducer material.

9. Apparatus as defined in claim 8, wherein first and second groups of said first conductors contain gaps arranged in transverse rows outside and on opposite sides of said overlapping area, respectively, and first and second groups of said second conductors also contain gaps arranged in transverse rows outside and on opposite sides of said overlapping area, respectively.

10. Apparatus as defined in claim 1 wherein said eighth layer of light transducer material and said ninth layer of conductive film are each divided into separate parallel strips, the strips in one of said layers registering with strips in the other thereof, said strips of each layer being arranged in groups, each strip of a group in one of said layers having a different color characteristic from the adjacent strip of its group, all of the strips of every group being arranged with respect to each other in an identical color relationship, means electrically interconnecting together only the corresponding strips of each group in said ninth layer, means for separately applying between each of the respective sets of interconnected strips and said fifth layer of conductive film a high frequency information signal modulated in accordance with the color characteristic of each set of strips, each one of said groups of strips being in registry with a conductor in one of the first or third conductor layers.

11. Apparatus as in claim 10y wherein each group comprises two side-by-side strips only, each of the strips of a group having a different color characteristic, each of said groups being identical and forming a two-color display means.

12. Apparatus in claim 10' wherein the strips of the ninth layer of conductive film have color characteristics and wherein the strips of the eighth light transducer layer are photoconductive whereby the apparatus functions as a camera. Y

13. Apparatus as defined in claim 1 wherein said ninth layer of conductive film is of semi-transparent material and is divided into sets of alternate strips, each of said sets transmitting one band of color different from another set, means electrically interconnecting together the same strips of each set, means for separately applying between each set of interconnected strips and said fifth layer of conductive film a high frequency information signal modulated in accordance with the color characteristics of said strips, the adjacent strips of the respective sets being in registry with a respective conductor in one of the first conductor layers. 4

14. A scanning tube comprising a plurality of parallel layers including, successively, a first layer containing a plurality of spaced rst conductors, a second layer of electroluminescent material, and a third layer containing a plurality of spaced second conductors, a substantial number of said rst conductors overlapping in angular relationship a substantial number of said second conductors to provide a scanning area, each of said rst and second conductors contains a gap outside of said overlapping area, the gaps of said rst and second conductors being disposed in rows extending transversely of said conductors, respectively, rst and second common terminal means connecting the ends of said rst and second conductors, respectively, beyond the respective gaps, 'rst and second triggering conductor means connected with said first and second common terminals, respectively, each of said triggering conductor means containing a triggering gap disposed adjacent to a gap of said first and second conductors, respectively, an impervious envelope enclosing all of the gapsvand containing an ionizable media; means for applying a direct current potential across the rst and second common terminals of a value slightly less than that required to create discharge in the gaps of the conductors connected thereto except upon the ionization of the media in the immediate region of and from an established discharge in an adjacent gap, means for periodically applying to said first and second triggering conductor means potentials for creating triggering discharges at said triggering gaps, respectively, and magnetic control 12 means extending along the lines of gaps for causing a discharge established in each triggering gap to move transversely and sequentially from gap to gap.

15. Apparatus in accordance with claim 14 wherein said magnetic means comprises pole pieces disposed along the opposite sides of said layers in alignment with the respective lines of gaps.

16. Apparatus in accordance with claim 15 including yokes interconnecting the respective pairs of pole pieces.

References Cited UNITED STATES PATENTS 2,598,392 5/1952 Kaell et al 313-156 2,612,625 9/1952 Hullegard 315-344 2,858,363 10/1958 Kazan 178-5.4 2,944,155 7/1960 Mayer 1785.4 3,012,095 12/1961 Skellett 1785.4 3,042,834 7/1962 Nicoll 315-169 3,142,819 7/1964 Duinker et al. 178-5.4 3,152,222 10/1964 Loebner 178-54 3,264,479 8/1966 Peek 315-169 JOHN W. CALDWELL, Acting Primary Examiner. DAVID G. REDINBAUGH, Examiner.

I. A. OBRIEN, Assistant Examiner.

Claims

1. A SCANNING TUBE, COMPRISING A PLURALITY OF PARALLEL LAYER INCLUDING, SUCCESSIVELY, A FIRST LAYER CONTAINING A PLURALITY OF SPACED FIRST CONDUCTORS, A SECOND LAYER OF ELECTROLUMINESCENT MATERIAL, A THIRD LAYER CONTAINING A PLURALITY OF SPACED SECOND CONDUCTORS, A FOURTH LAYER OF TRANSPARENT INSULATING MATERIAL, A FIFTH LAYER COMPRISING A FIRST TRANSPARENT CONDUCTIVE FILM, A SIXTH LAYER COMPRISING A PHOTOELECTRIC MATERIAL, AN OPAQUE SEVENTH LAYER COMPRISING INSULATING MATERIAL CONTAINING A MULTIPLICITY OF MINUTE CONDUCTIVE ELEMENTS INSULATED ONE FROM ANOTHER, AN EIGHTH LAYER COMPRISING AN ELECTRICAL LIGHT TRANSDUCER MATERIAL, AND A NINTH LAYER COMPRISING A SECOND TRANSPARENT CONDUCTIVE FILM, A SUBSTANTIAL NUMBER OF SAID FIRST CONDUCTORS OVERLAPPING IN A PREDETERMINED ANGULAR RELATIONSHIP A SUBSTANTIAL NUMBER OF SAID SECOND CONDUCTORS TO PROVIDE A SCANNING AREA, EACH OF SAID FIRST AND SECOND CONDUCTORS CONTAINING A GAP OUTSIDE OF SAID OVERLAPPING AREA, THE GAPS OF SAID FIRST AND SECOND CONDUCTORS BEING DISPOSED IN ROWS EXTENDING TRANSVERSELY OF SAID CONDUCTORS, RESPECTIVELY, FIRST AND SECOND COMMON TERMINAL MEANS CONNECTING THE ENDS OF SAID FIRST AND SECOND CONDUCTORS, RESPECTIVELY, BEYOND THE RESPECTIVE GAPS, FIRST AND SECOND TRIGGERING CONDUCTOR MEANS CONNECTED WITH SAID FIRST AND SECOND COMMON TERMINALS, RESPECTIVELY, EACH OF SAID TRIGGERING CONDUCTOR MEANS CONTAINING A TRIGGERING GAP DISPOSED ADJACENT TO A GAP OF SAID FIRST AND SECOND CONDUCTORS, RESPECTIVELY, AN IMPERVIOUS ENVELOPE ENCLOSING ALL OF THE GAPS AND CONTAINING AN IONIZABLE MEDIA; MEANS FOR APPLYING A DIRECT CURRENT POTENTIAL ACROSS THE FIRST AND SECOND COMMON TERMINALS OF A VALVE SLIGHTLY LESS THAN THAT REQUIRED TO CREATE DISCHARGE IN THE GAPS OF THE CONDUCTORS CONNECTED THERETO EXCEPT UPON THE IONIZATION OF THE MEDIA IN THE IMMEDIATE REGION OF AND FROM AN ESTABLISHED DISCHARGED IN AN ADJACENT GAP, MEANS FOR PERIODICALLY APPLYING TO SAID FIRST AND SECOND TRIGGERING CONDUCTOR MEANS POTENTIALS FOR CREATING TRIGGERING DISCHARGES AT SAID TRIGGERING GAPS, RESPECTIVELY, AND MAGNETIC CONTROL MEANS EXTENDING ALONG THE LINES OF THE RESPECTIVE GAPS FOR CAUSING A DISCHARGE ESTABLISHED IN EACH TRIGGERING GAP TO MOVE TRANSVERSELY AND SEQUENTIALLY FROM GAP TO GAP.