US2431115A - Color television system - Google Patents

Description

NW. 18, 1947. N, GOLDSMITH 2,431,115

COLOR TELEVISION SYSTH Filed Aug. 5, 1944 2 Sheets-Shoot 1 IllIIIIllIIIlllWllIlIIIllIIIIIIIIIIIIIHIHIHIHIll lllllll"IlllllllllllllllllllllIllllllllllllll |IIllIlllIlllllIIIllllllllllllllllllllllllmll mum:munmuummnmumnnmmu I ALFREDN-GOIDSMITH.

G R B BY ATTORNEY.

Y- 1947. A. N.'GOLDSMITH 2,431,115

COLOR TELEVIS ION SYSTEM Filed Aug. 5, 1944 2 Sheets-Sheet 2 LINE 7 SAW Team FREQUENCY REQUENCY WAVE lmppuszs MULTIP-IER FENERAIDR 7 APERIODIC AMPLIFIER vm-zo camel; l I Tim:

--D SIGNAL (man) J31 115 LIMITER ,5 129 117 121 TIME vlfizo SIGNAL 1 5 RED cumum. 161

ACTIVATING EIGNAL L 161 H' "to 1mm: vmzo SIGNAL ggwucmw qasmcumm 157 115 I l ACTIVATIN'G slGNAL vmzo SIGNAL l we cmmum. F1

ACTIVATING SIGNAL m m1 INVENTOR. ALFRED N. qowsmrrn.

monm Patented Nov. 18, 1947 UNITED STATES PATENT OFFICE COLOR TELEVISION SYSTEM Alfred N. Goldsmith, New York, N. Y.

Application August 5, 1944, Serial No. 548,240

27 Claims. 1

This invention is directed to television systems and is particularly concerned with improvements in electronic forms of television systems making use of cathode ray electro-optical image producing devices.

In its preferred embodiment, the invention is concerned with improvements in forms of apparatus of the type above stated where electro-optical images are made visible in colors closely approximating those of an original subject or scanned image. The image production in systems of this character is carried forward by socalled additive color combination method. To this end, provision is made for additively combining two or three, or even more, selected color components. By relating the color components in suitable manner and through suitable registry of the separate images a group of luminous color component images result, where the several individual component color images closely approximate the color separation images of the original in the several selected colors, and the complete image which results from the additive combination provides a reasonably acceptable approach to the natural overall luminous color density and color gradations of the original image.

By two concurrently filed applications for Letters Patent entitled respectively Color television, Ser. No. 548,238, and Multicolor television systems," Ser. No. 548,239, this applicant has disclosed two forms of color television systems wherein provision is made for both scanning and reproducing images in substantially their natural colors. While certain portions of these applications will have reference to the present disclosure, as will herein after be pointed out, the

present invention is concerned primarily with a means for producing color television images as electro-optical image reproductions on a single luminescent or fluorescent target or screen provided at one end of a cathode ray image producing tube.

Further, the invention is concerned with the provision of either one or two or three, or more, related and suitably controlled scanning electron beams for producing in registry the several component color images of a series to form additive color image representations within the cathode ray tube.

In the present form a camera the invention is concerned primarily with controlling circuits operating in conjunction with a cathode ray tube having a viewing target area formed of a great many long narrow strips of luminescent material arranged closely adjacent each other, A form of tube having a laminated color-striped target area formed from suitable compounds which luminesce in desired selected component colors has been disclosed in United States Patent No. 2,310,863, granted on February 9, 1943, to H. W. Leverenz. According to the disclosure in the Leverenz patent, which may be referred to herein for the purpose of illustrating one convenient method of target formation, a tricolor image may be produced to provide tricolor additive image pro-1 1:;- tion through the use of luminescent compounds intended to produce light under electron beam activation in three selected component or primary colors, such as red, green, and blue. As disclosed by the Leverenz patent, the red luminescent efiects may be achieved by a target formation of chromium activated aluminum berylliate or zinc cadmium sulphide activated with silver. achieved by providing alpha willemite activated with manganese and zinc cadmium sulphide activated with silver. Lastly, the blue effects may be caused to result from electron beam activation of a target area formed from silver activated zinc sulphide, zinc silicate and zirconium silicate. The particular luminescent compounds herein chosen for illustration are all disclosed in the Leverenz patent above named, as well as the general method to form the laminated screen and, per se, form no part of the present invention.

The present invention is primarily concerned, therefore, with ways and means to improve the operation of such systems and to provide controls whereby the various color target areas may be activated in the desired sequence to produce the multicolor image representations,

In a preferred form of operation of such a system, the target area of the tube, which is impacted by the scanning electron beam, is formed as a laminated or superficially color-striped structure, with the combined width of various laminated areas or longitudinal strips being such that the target sequence providing the red, the green, and the blue luminescent effects, for instance, shall all be confined within the width of a single normal width scanning trace, or even in a fraction thereof. Thus, for reference purposes, each of the strips or laminations from which the complete target is formed is to be considered as being no wider than A; that of the normal scanning trace. To practice the method and operation herein disclosed, the scanning electron beam, which is to produce activation of the target, shall have a cross sectional area no wider, in the direction of travel, than the width of each individual The green luminescent eilects may be strip. However, the height or length dimension, for instance, of the scanning electron beam may be greater than its width and may approach, or even equal, the width of one complete'scanning trace, which leads to the formation of a rectangular or elliptical scanning spot. Furthermore, according to the present invention, provision is made so that the scanning beam or beams which produce the difierent color electro-optical images shall be active only at times when sweeping or traversing the particular related color luminescent strip which is to produce the desired component or primary color image for combination with the other images to produce the complete fluorescent or luminescent combination, adding together to form the complete color image.

Various ways by which this control of the beam and the recording may be achieved are possible,

but the application will set forth, as one of the examples of such control, a system by which the deflected scanning beam or beams are controlled by a saw-tooth wave overcoming suitable biasing voltages so that the recording on difierent color strips or laminations ofthe target is possible.

Various modifications may be made whereby the phase of the controlling sawtooth wave is adjusted by suitable non-frequency discriminative means so as to shift thereby theactive point or active location of the scanning spot appropriately in order to provide the desired degree of registration on any component color. Thus, by the use of suitable biasing control means, the actu-' ating electron beam serving to produce the separate color images may be so controlled that successive effective registrations or impacts are located upon like color responsive areas of the target. The time and place of activation of the respective component-color scanning electron beams are thus individually and accurately controllable. In the case of simultaneous multicolor recordings, the successive impacts of the scanning beam follow, from one to another of the component colors in any desired sequence, but the beam control is successively switched from one controlling source to another so that the effect of simultaneous scanning of multicolor images is achieved by means of a uniformly moving scanning beam which i sequentially controlled as to its intensity. The correct phase relationship by which the video signals produce the desired color markings or recordings is so controlled that the signal modulated electron scanning beam traverses the desired component color strip or laminated area of the target in the desired manner.

The invention is also of such nature that simultaneous scanning of the striped or laminated target area may be achieved by a plurality of independent scanning beams each signal controlled or modulated by one only of the video signals representative of the several component colors. A system of this character utilizes at least two scanning electrons which impinge obliquely upon the target area. Compensation for the angle of impact is provided by way of special deflection control introduced along with the normal deflection wave operative on the usual electron beam deflection means. All foreshorteningeffects of red traced raster area are removed readily by one modification of the deflection wave and all lengthening effects are removed by a'diiferent or opposite modification of the deflection of the beam. Systems to accomplish this type of control efiect are disclosed in my above mentioned concurrently filed patent applications and, accordingly, are not discussedherein in any great detail.

Accordingly, it becomes an object of this invention to provide an impacted target surface within an electro-optical image producing tube which shall have produced thereon a plurality of component color images when activated by one or more suitably controlled scanning electron beams.

Another object of the invention is that of providing a system of tricolor or mutlicolor television image production wherein the images result in a plurality of chosen component colors which may be additively combined to produce a color image viding improvements in color television image producing systems by which television images in substantially natural colors may result with a simplification of the image producing apparatus; with a reduction in the number of component parts required by the installation; with a greater cheapness of installation, and yet with a higher degree of operational efficiency.

Other objects and advantages become apparent and will at once suggest themselves to those skilled in the art when the following description is read in' conjunction with the accompanying drawings, wherein:

Fig. 1 represents conventionally a section of a laminated target and shows, in schematic form, the scanning direction and scanning area of that target;

Fig. 2 represents a modification of the arrangement of Fig. 1, insofar as the general form of scanning is concerned;

Fig. 3 represents conventionally, by the portions a, b and 0 thereof, three separate controlled waves for influencing the scanning beam and for controlling the cycle of operation;

Fig. 4 schematically represents the general method adopted for simultaneous multicolor scanning of a target area in a tricolor system;

Fig. 5 diagrammatically represents one form of control system for utilizing the scanning arrangements of Figs. 1 or 2;

Fig. 6 represents a modification of the arrangement of Fig. 5 and provides a difierent form of signal scanning beam control; and

Fig. 7 schematically represents one form of amplifier and limiter combination suited for use with a system of Fig. 5.

Considering now Fig. l of the drawings, there has been disclosed a section of a target area i l intended for use Within a cathode ray, image producing tube of substantially known configuration. The tube, per se, is not shown for reasons of simplicity, but it will be understood that the target area, i I is positioned either as a separate element at the end of the tube or that the several striped or laminated sections of the target area i i are formed on the tube end wall in substantially the same manner luminescent target areas are depounds or upon which are mounted the various luminescent compounds carrying strips or filaments. Such a target then may be provided within a tube envelope in a manner closely approximating that represented, for instance, by the tube shown in the above mentioned Leverenz United States Patent No. 2,310,863. I

For the purpose of explanation it will be assumed that the target II as shown by Fig. 1, is formed from a series of strips l3, l3, and 11, respectively, which are formed of such compounds or materials, as aforesaid, to produce. when activated by a scanning electron beam l9, luminescent effects in red, green, and blue.

The impacting electron scanning beam l9, which is developed within the cathode ray tube according to known methods, and likewise suitably focused to the configuration shown, may be of circular formation as it strikes the target area. The beam deflection path is substantially that shown by the arrow 2| and thus is transverse to the direction of lamination of the target area. For all practical purposes the width of any one elemental area, or the height thereof, as it is formed in producing the color television image, shall be assumed to be equal to three strip widths, that is, equal to the combined transverse width of the strips l3, l5, and I! which is indicated immediately there beneath, by the dimension x. Likewise, if a substantially square elemental area is assumed, the height thereof, which is represented by the dimension y, will be equal to the width represented as 3st.

According to the method herein to be disclosed, the scanning spot I9, in the position shown in Fig. 1, may be assumed to be recording and tracing a path on the target area I I such that the red areas only are represented, in which event the beam will move between impact area l9 (shown in solid outline) and impact area l9 (shown in dotted outline) according to the directional path 2|. The dotted outlines between the impacting areas I9 and I9 indicate a conventional suppression long dimension thereof representative of the height of any one elemental area of the ultimately to be produced image, which has been assumed to be 11. The width of any one elliptical or rectangular scanning area will then, under the same assumed conditions, be equal to :c or, stated in terms of height, will equal one-third y. This narrow dimension corresponds also to the diameter of the scanning spot |9 as it impacts the target area l.

Where the operation and control is in accordance with the assumed sequential scanning pattern, the successive red areas will be impacted and the scanning spot having a shape such as the spot 20 will impact only the red responsive areas l3 and will fall successively at areas 20, 20', 20", and so on, along the scanning path 23. Electron beam suppression takes place at areas along the scanning path 23, indicated by dotted outline as separating the impact areas 20, 20', 20'', and so on. The manner of beam control to produce this suppression will later be explained herein.

In the modified showing of Fig. 2, elliptical scanning spots have also been represented for impact of areas |3, I3 and I! respectively, representing the red, the green, and the blue responsive sections of the target. However, in the arrangement shown by Fig. 2, it will be assumed that three separate scanning spots 30, 40 and 50. all of elliptical shape and of a type corresponding to the spot 20 shown by Fig. 1. are simultaneously active so that the red, the green, and the blue images may be produced at the impacted areas simultaneously. In this arrangement, as the scanning spots move successively to different strips or laminations of the target, they will follow the paths designated conventionally as 3|, 4| and BI, with a complete scanning direction being constituted in a direction transverse to the laminations and as represented schematicall by the arrow. While the spot 30 moves along the path 3|, for instance, to the next succeeding red responsive area; while the spot 40 moves along the path 4| to the next green responsive area; and while the blue spot 5|) moves similarly to the next blue responsive area, the electron beam producing the spot should be suppressed so that the beam which impacts the area 30, for instance, shall not be effective on any green or blue responsive strip of the target but shall next become operative in fact when the next red responsive target portion is reached. Provision is made for suppressing the scanning beam during this portion of the cycle as will be explained in reference to Fig. 3. Likewise, the scanning beams producing the impact areas 40 and 50 are controlled and suppressed in a motion from strip to strip of this target area.

In the scanning operations as described in reference to Figs. 1 and 2, the general method of controlling the electron beam or scanning spot so as to produce the desired color fluorescent effect need not be discussed -in any substantial detail, for in principle the method of controlling electron beam motion and the operational periods thereof has been set forth by my Patent No. 2,219,149, granted October 22, 1940, for "Television system. However, reference may be had to the showing of Fig. 3 of this application for general understanding of the broad principles of this method, although the aforesaid patent is to be considered also in this connection for such features as are shown therein.

Generally, a sawtooth wave, such as that represented by the wave formation 21, 29, 3|, 33, 35, 31, and so on, shall be utilized for controlling the cathode ray beam or scanning ray as it moves along the path represented, for example, at 2| on Fig. 1. The general deflection of the electron beam across the target area I may be controlled electromagnetically or electrostatically, as desired, this being, per se, no specific part of the present invention and disclosed, for example, in my above named patent.

Control of the electron beam as it passes between points I9 and I9, as in Fig. 1, or 20 and 20' in the same figure is provided by subjecting the scanning beam to a control by a voltage wave of sawtooth formation, as above represented. In this ,way, the time period, which is represented along the abscissa of Fig. 3, by the distance betweenthe points 21 and 3|, or 3| and 35, for instance, shall be regarded as the time required normally to move the scanning spot of the red component color image between the point [9 and the point l9, or, in other words, the time to move the scanning spot across three adjacent color strips I3, l5 and I1. During all the time that the scanning beam is thus being moved in the direction represented by the arrow 2|, 9. negative voltage of constant value. represented, for instance, by the magnitude of voltage between points 39 and 4|, is added to the sawtooth wave 21, 29, 3|, and so on, to produce thereby a new wave formation generally designated 43, 39, 29, 45, 41, 33, 49, 5!, 31, and so on. This wave, last named, then is impressed, in addition to the red component video signal modulation, on the control electrode of the electron gun forming the scanning beam so that during periods represented by time periods 63 to 39 and 45 to 47, for instance, the scanning beam is just suppressed, while during periods represented in time between the points 39 and 45, for instance, the scanning beam is effectively released and exists with an intensity then controlled given the cutofi bias value 39, 4!, the amplitude of the sawtooth wave 2?, 29, 3i is of course determined and the Video signal amplitude thus satisfactorily'controls the beam intensity between 39 and 45, during such time periods by the video signal modulation.

It thus becomes evident that with an arrangement of this general character the scanning beam for producing the image in any one component color (in a tricolor system) is active for approximately one-third of the total time, and inactive for approximately two-thirds of the total time, provided the subtractive biasing potential represented at 39, ii is properly selected. Furthermore, the scanning beam, under such circumstances, will become active to produce luminescent eifects in the target area it at exactly the correct time in the passage of the scanning beam over red responsive areas, while the beam is moved under the influence of suitable deflecting fields along the path 2!, as indicated.

In general, to insure this accuracy and registration, where the scanning beam is modulated during the time period 39 to 65, for instance, by the video signal, suitable phase shifting or phase adjusting elements should be provided in the signal controlled channel, it being understood that such phase shifting arrangements are non discriminative as regards to frequency. Phase shifting networks of this type then serve to shift the actual points of impact of the scanning spot on the target or screen area to the right or to the left in such fashion that the tive during the time period represented at 39, 65 shall register exactly with the corresponding component color strip. Phase shifting networks of various types are well known for this purpose and, accordingly, are not specifically illustrated. Reference may well be made, however, to the inclusion of any suitable phase shifting network arranged in the control circuit of the electron beam in such manner as to effect the desired function.

The deflection waves represented by curves b and c of Fig. 3 are similar in character to that wave above described and represented by curve a. However, the wave formations of Fig. 3 (b) and Fig. 3 (c) are marked similarly to the wave of Fig. 3 (a), but with prime or double prime, depending upon the curve. The Wave of Fig. 3 (b) is displaced relative to the wave of Fig. 3 (a) so that it leads Fig. 3 (a) by 120 electrical degrees and, accordingly, shall be regarded as controlling the image production of the video signal of those areas of the laminated target I I, which shall represent the blue color intensity, Likewise, the wave formation represented. by Fig. 3 (0) may be regarded as lagging the wave of Fig. 3 (a) impacting spot eflecr by 120 so that when the scanning electron beam is influenced by the last named wave, the image production shall be made to represent the green component color, so that if the scanning beam is active or signal controlled in the time period between 39' and 45', for instance, a. blue color representation shall be formed on the screen while, it active or released in the time period between 39" and 45", a green color representation shall result on the impacted target area ii.

Following a control of the ype hereinabove explained, further reference may now be made again to Fig. 2 which represents a method whereby any color component scanning spot skips the width of two color strips before reappear-lug, so that the scanning spot 30, for instance, moves while suppressed from the red fluorescent strip i3 to the next succeeding fluorescent strip i3, and so on.

A method of this character generally applies to simultaneous scanning of all of the adjacent component colors so that all of the signals representing the selected color components are always simultaneously variable, even though not all simultaneously utilized. Various ways to accomplish scanning in this form may be provided within the scope of the present invention.

One method to achieve this objective is to have the single scanning spot 30 of Fig, 2, for instance, controlled for a period corresponding to the period 39, d5, of Fig. 3 (a) of the red component color video signal. Then, this is to be followed by a control during the time period represented at ll, 39', for instance, of the blue color component signal, and so on. Here it is unnecessary to show the means by which the red, the green, and the blue component color signals are commutated electrically by means of the method generally represented by Fig. 3, nor yet the method by which these various signals may be briefly and serially applied in proper timed relationship to effect the desired control action, nor yet to illlustrate graphically the suitable duration of the signal control on the individual single scanning gun.

Another method by which the scanning pattern may be effective is to provide within the scanning tube three separate electron guns, as shown, for instance, by the general form of tube represented in my two above named concurrently filed patent applications. In a method where three electron guns, and consequently, three separate scanning spots of the type generally represented by the spots 23 of Fig. l, for instance, or 3d, 40 and 50, for instance, of Fig. 2, are provided, one of the scanning guns is arranged to project its scanning beam till of Fig. 4, for instance, in a plane as represented by the arrow immediately below the beam such that it strikes the target area it (such as along strip l3), substantially normally throughout the range of its motion or deflection. The result is that a substantially rectangular pattern, such as that conventionally represented within the rectangular area 53, 55, 51, 59 is usually traced, where the aspect ratio of the produced image area or raster is of the order of the customarily adopted four to three. Similarly, the scanning beam 70 from one of the other two scanning guns (not shown) which may be assumed to trace the scanning spot 40 representative of the green video signal modulation, will impinge upon the target area H at a point very closely adjacent that at which the beam 60 impacts the target, with theactual separation between the two spots 30 and 40 being of the order represented, for instance, by Fig.

' 2. With the scanning beam 10 emanating from to the side 53, 59 of the rectangle, with the displacement therefrom to the right substantially as represented by the spacin between the red and the green responsive areas i3 and 15 of Fig. 2. Likewise, the scanningbeam 80 shall impact the target area II at a point such as that represented at 50 in'Fig. 2, and it will, accordingly, trace also a trapezium shaped area conventionally marked 69, H, 13, I5, with the longest side H, 13 now being assumed to be substantial y contiguous to the side 55, 51 of the rectangle R, but displaced therefrom by two strip widths to the right so as to form the blue color image. Then the shorter side 69, 15 shall be contiguous with the long side BI, 61 of the rectangle G, but displaced therefrom to the right by the width of one color responsive strip.

To correct for this distortion. various methods and means were shown and particular y described in connection with my copending application entitled Color telev sion, Ser. No. 548.238, filed concurrently'herewith. and further detailed reference thereto need not be made. Any foreshortening for lengthening of the border or boundary areas of the formed image raster for any selected component color may be modified through the addition of suitable correcting voltages or currents in the deflecting wave form which is applied to the deflecting coils or plates for effecting an electro-magnetic or an electrostatic defiection of a cathode ray beam within a tube.

Accordingly, for the purpose of this disclosure it should be understood that the desire is to provide a system wherein the image rasters traced by all of the scanning beams 60, Ill and 80, tracing for instance, the red, the green, and the blue images, shall be corrected so as to coincide substantially and be displaced laterally one from the other by the width each of one-third of the maximum dimension of any one image point.

If reference is now made further to the method of operation disclosed by Fig. 3 which, for instance, might be suitable to control scanning beams such as those represented at 60, ill, and Bil of Fig. 4, there is included in the arrangement a suitable generator of sawtooth waves which will produce the waves 21, 29. 3|; 3|, 33, 35; 35, 31 and so on, as represented by Fig:3 (a) and, similarly the sawtooth wave formations represented by Fig. 3 (b) and Fig. 3 (c). The period of the sawtooth wave, as represented by the time conventionally represented between points 21 and 3|, for instance, will be equal to the time required to scan three strips of the laminated target area Ii, that is, the strips I3, i and I1. The scanning of these strips or laminations of the target I i is assumed to be along a path transverse to the strips as represented, for instance, by 2!, so that the sawtooth waves occur at a frequency closely approximating or equalling one-third of the total number of scanned strips or laminations per traversal of the scanning electron beam or ray along any linear path.

To achieve the object of controlling the scanl0 ning ray or beam in the desired fashion to produce tricolor image representations for instance, three separate sawtooth waves must be developed and these must be made to be capable of adjustment to the correct phasal position to represent the correct color scanning with the phasing being as above stated 120 electrical degrees from each other. The amplitude of the sawtooth wave, in each instance, shall be of such value that there can be added thereto a constant negative bias equal, in the case of tricolor images, to approximately two-thirds of the peak amplitude. The

, resulting brief sawtooth peaks, so to speak, are

then arranged to be passed through an A.-C. amplifier of either aperiodic or non-frequency discrirninative character within the range of frequencies required properly to reproduce the sawtooth peaks. Of course, as an optional arrangement the sawtooth peaks might be sent through "a limiter whereby they are converted essentially to square waves of a length equal to the time of scanning one elemental strip or lamination approximately, and then suitably sequentially phased. The peaked sawtooth waves or square waves then are preferably applied to an amplifier in the video signal circuit leading to the control electrode of the image producing tube in such fashion as to release the cutofi bias during the desired time period of operation, as represented by the selected sawtooth or square wave peaks.

Reference may now be made to the schematic diagram of Fig. 5 where a source of line frequency impulses is schematically represented at iii. The line frequency impulses so developed may be produced in any desired manner and preferably are triggered under the control of incoming line synchronizing impulses, or the pulse source may be constituted by the actual received line synchronizing impulses. Signal impulses at this frequency are then supplied to an appropriate frequency multiplier unit 83 in which they are suitably multiplied.

Generally speaking, the unit 83 consists of a plurality of stages in that its object is that of developing impulses at multiples of the line frequency which correspond to the number of image elements or points which are to be produced within the raster traced by the scanning cathode ray beam.

In a system wherein thirty complete scannings occur per second, and where an image raster having four to three aspect ratio is produced with 525 separate scanning lines, it will be apparent that, for purposes of calculation, each scanning trace or line may be assumed to be composed of 700 elemental areas or points. With the scanning beam being required to trace, in the production of each elemental point of the resultant image, three separate component color areas, such as I3, [5, and IT, for instance, it will be apparent that the frequency at which the sawtooth waves energy, such as 21, 29, 3|, 33, 35, and so on, are developed, shall correspond to the line frequency multiplied by the number of points per line, so that, in the illustrated example, frequency multiplication of 700 to 1 may be assumed to take place within the frequency multiplier unit 83. The unit is represented schematically since, per se, the circuits included do not constitute a part of the invention and any well known form of frequency multiplier unit which will produce the same general form of output in the nature of pulses may be utilized.

The output signals occurring at the multiple frequency and appearing in the output of the frequency multiplier 03 are then supplied to a suitable sawtooth wave generator unit 85 for the purpose of triggering it'and producing the sawtooth wave form of the general configuration represented, for instance, by any one of the curves of Fig. 3. The output energy or voltage waves from the sawtooth generator 85 are then passed through suitable conductors 81 and 89 which connect with quarter-phase coils 9| and 93, with coil 9| being connected to the conductors 81, 89 I through a capacitor 90 so that a rotating field is developed by the coils. Separate pickup 00115 95, 96 and 91, of which the schematic representation of Fig. 5 shows a proposed circuit for .one only of these coils, are located 120 electrical degrees apart from each other within this electrical field.

In order to adjust the exact phase of the output of the coils 95, 96 and 97! to a proper relationship with respect to each other and the several component color image reproductions which are instantaneously to be produced in the luminescent strips I3, I5, I! of Fig. 1, for instance, which strips from the target area of the image producing tube I 00, the several coils 95, 96 and 9'! are accurately rotatably adjusted in the directions shown by the arrows about a central point within the rotating field of the coils 9| and 93, The foregoing constitutes an additional manner over that herein before suggested for producing the several wave forms represented for instance, by the curves a, b, and c of Fig. 3, thereby to induce into the load circuits connected to the several pickup coils 95, 96 and 91, electrical waves bearing the desired phaseai relationship with respect to each other and at the same time being of the desired wave configuration.

The method shown for providing the sawtooth electrical waves of the appropriate frequency and of appropriate phaseal relationship relative to each other is merely one of several which may be adopted for the purpose of this invention. Accordingly, the form shown is to be considered as illustrative and it will be realized that alternative electrical methods, already known in the art, may be used within the scope of the invention.

The output energy from the pickup coil 95 is suitably amplified in an amplifier IOI which may be of any desired and conventional design, such as is well known in the art. Output energy from the amplifier I is then supplied to a further aperiodic a p fi r I03 also of conventional character. The output signals passing from amplifier I M to the aperiodic amplifier I03 are supplied through a potentiometer I05 to which the variable tapping point I01 leading from amplifier IN is connected.

The drawings illustrate a biasing source I09 in the form of a usual battery arrangement so poled that a suitable negative bias, represented in Fig. 3 by the line 39, 4I and in the wave diagram is effective upon the aperiodic amplifier I03 an electrical wave which may be considered as being the wave form 39, 29, 45, 41, 33, 49, 5i, and so on. This is not however directly applied to the video control grid of tube I I,

This activating wave form is then further distortionlessly amplified in the aperiodic amplifier I03 until this wave form may be considered, for illustrative purposes, as corresponding to the wave form represented in Fig. 5 adjacent that portion of the conductor between the aperiodic amplifier I03 and a limiting device II3. In the limiting device I I3, desired limiting effects may be achieved whereby in the output a generally square wave formation, diagrammatically represented at H5, H1 in the output of the limiter H3, may result.

Figure 7 shows one form of circuit to illustrate suitable amplifier and limiter units for use as the elements I03 and H3 of Figure 5. In this arrangement, the incoming signals which overcome the biasing voltage applied by the source I09 are fed to the input of the wideband amplifier tube I02. This tube is preferably, though not essentially, one of the so-called pentode variety. Usually, the tube is self-biased, as indicated. The output circuit of the tube may include the peaking coil I04 to prevent a falling response char acteristic with increasing frequency of the input signal. The usual load resistor I06 is connected in series with this peaking coil to a suitable source of voltage not shown. Output signals which appearacross the load resistor I06 are then supplied, by way of the condenser I08 and the resistor I I0, to the control electrode of a clipper or limiter tube II2. This tubepreferably has its cathode connected to ground as well as the grid resistor II4, which connects between the junction of the coupling condenser I08 and the input resistor I I0. With this arrangement, it will be apparent that the resistor H0 functions to prevent the grid from going very positive during the peak input pulses, such as those indicated in Figure 5. When the grid does become slightly positive, grid current flows through the resistor IIO, as well as the grid resistor H4, and a negative voltage is developed which acts as the bias to limit the positive voltage on the grid. During periods when peak pulses are not present, electrons in the grid condenser I08 flow to ground through the grid resistor I I 4 and set the bias level. The time constant of the condenser I08 and the resistor I I4 is usually, large compared with the period of the input voltage. The square wave output signals from the tube H2 are then supplied to the conductor I29,- as indicated more particularl by Figure 5. The dotted outline rectangles I03 and H3 show the corresponding parts in Figure 5.

It is, of course, optional whether or not the limiter I I3 be used, for the output of the aperiodic immediately adjacent amplifier IOI as the value :1: must be overcome before any wave energy is applied to the aperiodic amplifier I03. Thus, a biasing voltage which may be assumed to be equal to two-thirds or the peak amplitude of the sawtooth wave output from amplifier IOI may be azsumed to be effective in the aperiodic amplifier For illustrative purposes, in Fig. 5 the wave form shown to represent the output from amplifier IN is assumed to have the same characteristics as that wave form represented by Fig. 3 (a), and, accordin ly, like numerals refer to like operations of the electrical wave assull'ifi r Thus, there amplifier I03 may be assumed to be the controlling wave where desired, but for practical consideration it is usually convenient to depend upon the square wave form illustrated H5, H1, and so on.

The amplitude of the square wave I I5, I I1, and so on, is usually made greater than the cut-off bias of the controlled tube later to be described, so that the tube controlled may be carried to a cut-off state under conditions when signal is lacking in the amplifier channel associated with pickup coil 95, but which will become effective during signalling periods.

In order that images may be produced on the target area II of the image-producing cathode ray tube I00, an electron beam, conventionally represented at H9, is developed within the tube between the cathode I 2| and the anode I23 for instance, and this beam is then directed toward the target area II in the'well known manner. Control of the developed electron beam or cathode ray H9 is effected by means of a control electrode or grid element I25 usually Placed Within the tube intermediate the cathode and the anode and formed as a part of the beam developing electron pin.

Biasing voltages are applied to the control electrode I25 from the biasing source conventionally represented at I21. Accordingly, with the biasing source I21 being poled relative to the control electrode I25 so as normally to carry'the control electrode negative, it is apparent that the electron beam II9 will normally be suppressed in the absence of some triggering voltage where the bias voltage supplied fromthe source I21 is equal to a cut-off value for the tube.

Thus, it may be assumed for illustrative purposes that the electron beam developed within the tube I III) is normall suppressed and ineffective to reach the screen or target I I by the action of the biasing source I21. However, due to the output from the limiter II3 being connected to the control electrode I25 through conductor I29 and the biasing source I21, it becomes apparent that during periods represented by the time of occurrence'of the square wave pulses H and II1, for instance, in the output of the limiter IIB, the biasing effect of the biasing source I21 may be overcome and electron beam II9 duly formed.

Thus, the signal output from the limiter II3 serves to cause the electron beam or cathode ray I is alternately to be formed and then suppressed,

' with the period of suppression being twice as long in the example illustrated as the period of beam formation.

Simultaneously with the control of the formation of the electron beam H9 under the influence of the output signal or square wave pulse from the limiter H3, a video signal is assumed to be supplied at the input terminal I3I and to be fed through conductor I33 to the bias source I21 and the control electrode I25. If the video control signal (which is assumed to be developed from any suitable receiver which is not shown) applied at the input terminal I3I is to represent a red version of the image, then it is apparent that during periods of time that the electron beam H9 is formed (that is, during time periods corresponding to the duration of the pulses II5 and H1 for instance), the formed electron beam will be modulated under the control of the red video signal. 7

Suitable means for deflecting the formed electron beam I IS in bi-directional paths across the target area II to form the desired image raster are provided by way of the conventionally represented deflecting coils I35 which are customarily formed in a yoke surrounding the tube neck.

It is of course evident that the showing of Fig. 5 is purely illustrative of a conventional means of controlling an electron beam in a tricolor image-producing system insofar as the control of one of the component color images only is concerned. For the control of the two other color components of the tricolor image-producing system, and for the purpose of showing more directly the relationship of all the component colors with respect to each other, reference may be made more particularly to the showing of Fig. 6, in that the method illustrated by Fig. 5 is more particularly applicable to the control of a herein by Fig. 4) which each direct an electron beam toward the target area II. Thus, Fig. 5 illustrativeiy represents the control or one only of the produced electron beams; the control of the other two electron beams, i. e., for instance, the electron beam forming the green and the blue color components of the complete tricolor image, may be assumed to become efl'ective under the influence of the signal generated in the pickup coils 86 and 91, which are each positioned 120 (electrical degrees) out of phase relative to the pickup coil 85.

Control of the auxiliary electron beams. such for instance as those represented at 10 and II for the green and the blue images, may then be assumed to be developed by way or control systems, which are counterparts of that hereinabove explained in connection with the assumed red color control as derived from pickup coil 95, except that the 120 electrical degrees phase displacement exist between their respective outputs as previously described.

Referring now, however, more particularly to Fig. 6 for a description of a system wherein a single electron beam forming means only is utilized to direct a formed electron beam or cathode ray toward an image-producing target or screen area II, there has been shown a control efiected through a series of independent amplifier units. These amplifiers may be represented at I for the red signal, at I43 tor the green signal, and at I45 for the blue signal. Each ampliher is purely of conventional design and corresponds to those used customarily as the output amplifiers in the usual forms of known television image-producing arrangements.

To eifect a control of the amplifier units Ill, each may be provided in the initial stage, for instance, with a multi-grid control tube, to the inner grid of which a biasing signal is customarily applied and to an outer grid to which a video modulation signal of the corresponding component color is customarily applied. It can be assumed the video signal representative of the red component color image is now applied at an input terminal conventionally represented at I 5|, and then directed by way of a conductor I53 to the amplifier unit MI. The amplifiers HI, I43, I45 must be capable of amplifying substantially distortionlessly at frequencies at least as high as the activating impulse frequency.

The activating signal. which will correspond to the square wave control signal shown as appearing in the output of the limiter II3 (Fig. 5 for example) is then applied to the activating signal input terminal I 55, and then supplied by way of conductor I51, and bias source I59 to the inner control electrode of the first tube of the amplifier unit Ill. The bias battery or bias source I59 then may be assumed to be of magnitude sufficient normally to drive the first amplifier tube of the amplifier unit Ill to a cut-oil state in the absence of any control signal adequate to overcome the effect of the bias source.

The control signal applied at the terminal III, which signal is represented by the square wave f l5 output of the limiter such as H3, is of the magnitude suflicient to overcome the effect of the bias source I59 driving the amplifier I to cutoil'. Accordingly. during periods of time when square wave pulses such as H5 or II! are applied at terminal I55, the amplifier MI .is brought to an operative state and the video signal applied at terminal I5I is then capable of controlling the amplifier and developing a suitable controlled signal output therefrom which is applied through the output conductors IBI and I63 to an output terminal I65 herein assumed to be connected to the control electrode I25 of a tube such as that shown by Fig. 5.

This last named connection may be efiected through the intermediary of any suitable biasing means for the image producing tube. I which will initiate an optimum state of operation therein.

So that the green image representation is produced to follow in sequence the red image production, the video signal representative of green is continuously applied to the video signal input terminal I6! and directed to the amplifier I43 through a. conductor I69. This amplifier I43 is of the same general character as that above explained in connection with amplifier lit for the red signal channel. So that the amplifier I 4! shall normally and in the absence of a control signal pulse be biased to a cut-ofi state, a biasing source *III is connected intermediate the amplifier and an activating signal input terminal W3. A. control pulse of the general character of that shown, appearing in the output of the limiter H3 in Fig. 5, is assumed to be applied at the activating signal input terminal I13, it being understood however, that the activating signal is delayed 120 electrical degrees in phase relative to that signal applied at the activating signal input terminal I55 above mentioned.

Accordingly, during periods of time when the activating signal applied at the terminal I13 causes the amplifier H433 to become active over the efiect of the 'cut-ofi bias applied from the source H I; any video signals which are applied at the input terminal I61 will be suitably amplified and appear in the output conductor I75, from which they are supplied to conductor I63 and caused to control the modulation of a suitable electron beam through the control electrode of the cathode ray tube which is connected to the terminal I55.

With the control system efiective on the green channel being delayed with regard to the red signal by 120, it is apparent that the green signal becomes effective to modulate the developed cathode ray beam at a time when the red image signal amplification is interrupted, so that the sequence of operations brings the red signal modulation to be followed by the green signal modulation.

The remaining one-third of the complete cycle thenis to be effected by the blue image signal production, which is brought about by supplying the blue video signal to the input terminal ill and directing itto the amplifier I45 through conductor I19. A biasing source I8I, connecting intermediate amplifier H and the activating signal input terminal I83, holds the amplifier I45 in operation or at a cut-off state during periods of operation of each of the red and the green signal amplifiers MI and I 43. But where the activating signal applied at the input terminal I83 is delayed 240 electrical degrees relative to the signal applied at the terminal I35 and is delayed 120 electrical degrees relative to the signal supplied at the activating signal input terminal I13, and all of the activating signals are of the same time duration, it is apparent that amplifier I45 will follow the operation of amplifier I43 and its output signal may then be supplied by Way of conductors I83 and I63 to take over the control of the image production in the tube I00; after which the complete cycle above will be repeated.

In this way the eifect of image production, of the general type illustrated by Fig. 2, is achieved with the production of the image points 30, it and 50 for instance being determined in accordance with the operative periods of the red, green and blue amplifiers I4I, I43 and I45; and the blanking periods between successive like image color representations, such as those periods represented in Fig. 2 at 3|, 4| and 5| for instance, are determined by the periods during which the biasing sources I59, Ill and I8I for instance hold the amplifiers I4I, I43 and I45 in a cut-ofi state.

An arrangement of the type last described is, of course, one in which the formed electron beam M9, for instance, is continually subjected to the action of deflecting period tending to cause it to trace a sequence of lines across the target area II, and then after each line is traced the beam is moved downwardly for instance to trace the next succeeding parallel trace. Obviously the traces across the target area I I may be such that the rapid component of motion is horizontal (the present customary method for scanning), or vertical as desired. Further, each component-color video signal is active and in control of the scanning beam at times when that beam impinges on a fluorescent line of the corresponding color. As previously stated, adjustment means may be provided to secure initially and to maintain the cor responding registry.

An arrangement of the type last described, and particularly referred to by Fig. 6, of course does not necessitate the elaborate area distortion corrections which would be required in the case of a multi-beam tube of the character noted by Fig. 4, and the application of a series of controlling or activating signals, such as those derived from the pick-up coils 95, 96 and 91, being made to become efiective at the input terminals I55, I13 and I 83 causes the effect of electronic switchin between the successive controlling colors.

In the foregoing description and in the claims to follow it will be understood that reference to the term element may mean either a linear or a point element. Accordingly, an element in an area having at least one extremely small dimension which is significant and relevant to the described process so that a point or element may, for general consideration, be regarded as a minute circle, a square, a rectangle, an ellipse or the like, having the major dimension of minute size. Further in this connection, it will be understood that a linear element is essentially a narrow strip and is usually straight. It is to be considered as having one finite dimension along its length and one extremely minute dimension (theoretically infinitesimal), which may be regarded as being along its width. In this way the significant and relevant dimension of a linear element as related to television scanning must be its minute width so that, in effect, a linear element acts and appears as a linear assembly of a multiplicityof point elements.

Further, in the foregoing description it might be assumed, at least by inference, that the target strips across which the electron beam is to scan are each of equal width or substantially such thereso. When the target strips are actually of equal width, it will be appreciated that the luminescent compound coatings thereon must be of such character that for any given beam current and any given period of beam impact on each strip of the target, intensities of light will be developed in the several chosen component or primary colors which will summationally add to white or shades of neutral gray. When such is the case, then it becomes evident that the pulses controlling the times of successive beam formation in the case of multiple beam tubes, or signal modulation of one beam by signals representative of one color in the case of a single beam tube controlled in sequence by signals of the several component colors, will be delayed in phase with regard to their active periods relative to each other by a phase delay equal to 21r/C, where represents the number of component colors in the color series.

However, it sometimes happens that the luminescent materials or compounds which produce light in the several component colors such as the red, the green and the blue, for instance, do not always develop light with relative intensities meeting the condition for an additive efiect of white or neutral gray. Therefore, to compensate for such variances in order that white or gray light may result from the complete color series, it occasionally becomes necessary or at least desirable to vary the Width of the several strips of each color strip series relative to each other, or simultaneously to vary the current in the diiferent beams of a multiple beam system, or the beam velocity or current from time to time in a single beam system, so that substantial color equality is produced. Under these circumstances, if a system of additive color be assumed where the red, the green, and the blue follow each other in se quence to form one color series, then it may be assumed that the width of the red strips will each be equal to dr, the width of the green strip 1 being represented by dg, and the width of the blue strip being represented by db. Now, under such circumstances, the phase displacement of the control pulses hereinabove described for the several beams or the pulses for controlling the time periods when the impressed modulation signal energy is effected on one beam may be considered, for instance, as being zero (0) for the red beam; but, for the green beam, under these circumstances, it will be displaced from the red by an amount which is equal to while the blue beam will be displaced from the red beam by an amount equal to r+ g+ i) The foregoing will be apparent in view of the fact that the phase displacement now becomes determined in accordance with the tim required for one or a multiplicity of electron beams to scan or traverse each of the several strip elements in directions transverse to the strip length and then to enter upon the next adjacent strip.

Accordingly, for the purpose of this invention,

as it is defined in the claims to follow, it will be understood that references to the phase delay shall be broadly considered on the basis that the strips are actually of equal width notwithstanding the fact that this condition may not always be prevalent; and further within the meaning of the claims herein presented, it will be appreciated that reference to the periods of beam formation and beam suppression shall be broadly construed as applicable to systems with equal width target strips as well as to systems with unequal width target strips. Likewise, references to the method and/0r means of synthesizing the modulation control with beam impact or the concatenation of the scanning with a modulation control shall be such that the proper impressed signal or the proper impacting beam strikes the target at areas to produce the desired color response.

While the invention has been described in its preferred forms, it is of course to be understood that many and various modifications may be made within the spirit and scope of what is hereinabove set forth, and I therefore believe myself rightly to be entitled to make and use any and all of these modifications as fairly suggest themselves from what has hereinabove been set forth.

Having now described the invention, what is claimed and desired to be secured by Letters Patent is the following:

1. A color television system comprising an electron tube having a built-up target area formed as a repeating series of strip-like elements with the target elements of each series being of materials adapted to fluoresce upon electron beam impact in each of a predetermined number of component colors to provide additive color images, means to deflect and concurrently modulate the electron beam under the sequential control of separate video signals equal in number to and representative of each of the selected component colors of the additive color system to provide intensity control of the color response in each color, means for developing beam control energy having a predetermined relationship to the line frequency at which produced color images are to be developed to limit the periods of active beam response and suppression, means to gen erate from the control energy a series of control pulses out of phase with respect to each other by predetermined amounts, and means for utilizing the said phase shifted pulses to control the time periods during which signals representative of the several component colors are applied to control the image production.

2. A color television system comprising an electron tube having a built-up target area formed as a repeating series of strip-like elements with the target elements of each series being of materials adapted to fluoresce upon electron impact in each of a predetermined number of component colors to provide additive color images, mean to develop an electron beam, means to deflect the electron beam relative to the target area to cause the beam to trace a scanning raster thereover,

means to modulate the deflected electron beam in sequence under control of video signals representative of each of the selected component colors of the additive color system to provide in sequence intensity control of the beam in different color response, means for developing beam control energy having a predetermined relationship to the line frequency at which produced color images are to be developed to limit the periods of active beam response, means to generate from the control energy a series of control pulses out of phase with respect to each other by predetermined amounts and means for utilizing the said phase shifted pulses to control the time periods during which signals representative of the several component colors are applied to control the image production.

3. In a tricolor television system wherein is included an electron tube having a target area formed as a repeating series of elongated strips adapted to luminesce, under electron beam impact, to produce light effects in the several component colors of a tricolor additive system, and

wherein a plurality of electron beams equal in direction transverse to the lengthwise dimension of the elongated strips and a relatively slow deflection being in a direction lengthwise of the strips, generating controlling wave energy for controlling the time of formation and suppression of each of the deflected electron beams, shifting the phaseal relationship of the developed wave energy for controlling the plurality electron beams so that the beams are formed in sequence to reach the impacted target area so that each formed electron beam impacts strips of one character only in the series and remains inactive during remaining periods of deflection transverse to other predetermined color image producing strips of the target, and modulating the formed electron beams by signal energy representative of the coordinated color response indications developed upon the target area, by the impacting beam.

4. A color television system comprising an electron tube having a built-up target area formed as a repeating series of strip-like elements with the target elements of each series being of materials adapted to fluoresce upon electron impact in a predetermined number of component colors to provide additive color images, means to develop an electron beam and deflect it to trace a scanned raster on the target, means to modulate the deflected electron beam under control of video signals representative in sequence of each of the selected component colors of the additive color system to provide intensity control of each color response, means for developing beam control energy having a predetermined relationship to 20 of a single color response only with the scanning being in a direction transverse to the strip elements and means to restrict the scanning of the target by individual electron beams each to areas of a single color response only.

6. Electronic apparatus of the class described comprising a support surface element, a multiplicity of elongated coated and color responsive impact strips each of a sub-elemental width and each secured to said support surface element, said coatings of the impact elements of the sub-elemental width strips being of a plurality of materials adapted to effect a response under electron impact which closely approximates predetermined colors of a multicolor additive color system, the said groupings of the said sub-elemental width strips being such that substantially at least one coated element of each color response is included within an area corresponding to an elemental area of finite size, and means for developing a plurality of modulatable electron beams each adapted to be directed toward the said support surface element to scan individually the sub-elemental width coated strips of a single color response only with the scanning being in a, direction transverse to the strip elements.

the line frequency at which produced color image raster is developed, means to utilize said control energy to limit the periods of active beam response by generating from the control energy a series of control pulses out of phase with respect to each other by predetermined amounts and means for utilizing the said pulses to control the time periods during which signals representative of the several component colors are applied to control the image production.

5. Electronic apparatus of the class described comprising a support surface element, a multiplicity of elongated coated and color responsive impact strips each of a sub-elemental width and each secured to said support surface element, said coatings of the impact elements of the sub-elemental width strips being of a plurality of luminescent materials adapted to produce a color response under electron impact which closely approximates predetermined colors of amulticolor additive color system, the said groupings of the '7. Electronic apparatus of the class described comprising a support surface element, a multiplicity of elongated coated and color responsive impact strips each of a sub-elemental area width and each secured to said support surface element, said coatings of the impact elements of the subelemental width strips being of a plurality of materials adapted to effect a response under electron impact which closely approximates predetermined colors of a multicolor additive color system, the said groupings of the sub-elemental Width strips being such that substantially at least one coated element of each color response is included within an area corresponding to an elemental area of finite size, and means for developing a plurality of modulatable electron beams each adapted to be directed toward the said support surface element to scan individually the sub-elemental width coated strips of a single color response only,

8. In combination with electronic apparatus of the class described comprising a support surface element and a multiplicity of elongated coated and color responsive luminescent impact strips each of a sub-elemental area width secured to said support surface element, said'coatings of the impact elements of the sub-elemental width strips being of aplurality of materials adapted to luminesce under electron impact which closely approximates predetermined colors of a multicolor additive color system and the said groupings of the said sub-elemental width strips being such that substantially at least one coated element of each color response is included within an area corresponding to an elemental area of finite size, means for developing a plurality of modulatable electron beams equal in number to the number of separate color luminescent impact strips in each series and each adapted to be directed toward the said support surface element to impact the surface approximately orthogonally and each to scan individually the sub-elemental width coated strips of a single color response only with the scanning being in a direction transverse to the strip elements, and interlocked and interrelated means to modify the uncorrected scanning path for each beam to establish uniformity in path length separately from the deflection,

thereby to establish registry of pattern of each scanning.

9 Electronic apparatus of the class described comprising a support surface element, a multiplicity of elongated coated and color responsive impact strips each of a sub-elemental width and each secured to said support surface element, said coatings of the impact elements of the sub-elemental width strips being of a plurality of luminescent materials adapted to produce a color response under electron impact which closely approximates predetermined colors of a multicolor additive color system, the said groupings of the said sub-elemental width strips being such that substantially at least one coated element of each color response is included within an area corresponding to an elemental area of finite size, and means for developing a plurality of modulatable electron beams each adapted to be directed toward the said support surface element to scan individually the sub-elemental width coated strips of a single color response only with the scanning being in a direction transverse to the strip elements.

10. In a tricolor television system wherein is included an electron image producing tube having a target area formed as a repeating series of elongated strips adapted to luminesce, under elec-. tron beam impact, to produce light in the several component colors of an additive tricolor system and wherein an electron beam is developed within the tube for scanning the component color producing strips along paths transverse to the strip length at a relatively high rate and along the length of a relatively slow rate to trace an image raster, the method of producing cyclically additive color images which comprises supplying modulation signal energy representative of each of the selected component colors to modulate the developed electron beam, continuously applying to the electron beam control a series of biasing voltages normally tending to nullify the modulation effect of signals supplied, generating control wave energy pulses, producing from the control wave energy pulses a plurality of phase shifted variances thereof with the phase shift between the different signals being equal to 21r/C where c is the number of component colors in the additive system, and utilizing the phase shifted variances in the control wave energy pulses for sequentially overcoming the biasing efiect on each of the impressed component color modulation signals so that the component color signals sequentially modulate the developed electron beam and luminescent effects in the selected component colors on the target area are developed with the intensity thereof controlled in accordance with the applied signal energy. 4

11. A tricolor television system wherein is included an electron tube having a target area formed as a repeating series of elongated strips adapted to luminesce in the several component colors of a tricolor additive system when the component color sections are activated by an electron beam impacting thereon and wherein a plurality of electron beams equal in number to the number of different component color producing strips in the series are developed with each electron beam being adapted to impact the target,

the method of producing additive color imagesv on the target area which comprises deflecting each of the developed electron beams simultaneously across the target in directions substantially normal to the elongated dimension of each of the strips of the luminescent material, con- 22 catenating the deflections so that the different electron beams impact adjacent color responsive strips and so that like strips of each component color responsive section of the series are sequentially located in the path of one of the developed electron beams, applying modulation signals of one component color only to each of the developed electron beams, generating control wave energy, producing phase shifted variations of the control energy and applying control wave energy of a different phase individually to each of the developed electron beams so that as all of the beams are deflected relative to the target one only is active to cause target luminescence with the other being transverse to the length of the strips of the target and with a relatively slow motion of deflection being lengthwise of the strips, means for developing control pulses of energy for controlling in sequence the suppression and the formation of the said electron beams so that during the simultaneous deflection of all of the electron beams one only-is instantaneously active upon one component color response section of the target and the sequence of activity and suppression is coordinated with a number of color response strips in the target and means for applying modulation signals to the independent electron .beams so that the plurality of electron beams are modulated by signals representative of one component color for time periods during which action of the related component color target area is interrupted.

1 3.' A tricolor additive television system including a cathode ray tube having a target area formed of repeating series of elongated strips adapted individually to luminesce under electron beam impact in each of three primary colors of an additive tricolor sequence, means for developing three independent electron beams and for directing the said electron beams toward the target area along a plurality of beam projection paths each angularly disposed relative to a normal to the target area and to each other, means for deflecting each of the said electron beams relative to the target along bidirectional paths with the deflection in the direction transverse to the strip elements of the target being relatively rapid and the deflection in a direction lengthwise of the target strips being relatively slow, means for developing control wave energy for controlling the time period of formation and suppression of the individual electron beams, said formation periods being related to the time duration required to transverse, in the direction of rapid motion, the target strip corresponding to one primary color only of three strips forming each series, means to develop three phase shifted variations of the said control energy to control in a predetermined cycle the periods of formation of electron beams so that during active periods of one beam the remaining beams are suppressed, means for applying modulation signals to modulate the electron beams to produce color responses in the primary color response areas of the targets in accordance with the modulation signals applied and means for adding predetermined increments of control energy to the deflection energy to control the rates of beam deflection for each of the said electron beams to modify the scanning trace and rate and to provide a substantially orthogonal target traces from each of the scanning beams.

14. In a tricolor television system wherein is included an electron tube having a target area formed as a repeating series of elongated strips adapted to luminesce, under electron beam impact, in three chosen component colors of a tricolor additive system, and wherein three distinct electron beams are developed to impact the target each from a difierent angle relative to each other and each at an acute angle to a. normal to the target, the method of producing additive color images which comprises simultaneously and relatively rapidly deflecting each of the developed electron beams across the target area in a direction transverse to the direction of the elongated strips and relatively slowly longitudinally of the strips to scan an image raster area, generating a series of three distinct controlling wave energy pulses from the deflection controls for controlling the time periods of formation and suppression of each of the deflected electron beams, shifting the phaseal relationship of each of the control wave energy pulses developed from the deflected wave energy so that the several electron beams become active in sequence to impact the target area while traversing strips of one character in the series and remain inactive during remaining periods of deflection transverse to predetermined color image producing areas of the target, modulating each electron beam by image signals representative of one only of the component colors, and synthesizing the periods of signal application with periods of beam formation and target area impact of the electron beams and resulting color response indications on the target area. I

15. A tricolor additive television system including a cathode ray tube having a target area formed of repeating series of elongated strips adapted individually to luminesce, under electron beam impact, in each of a plurality of primary colors of an additive color sequencmmeans for developing three independent electron beams and for directing the said electron beams toward the target area along a plurality of projection paths each angularly disposed relative to each other and to a normal to the impacted target, means for deflecting each of the said electron beams relative to the target along bidirectional paths with the deflection in a, direction transverse to the strip elements of the target being relatively rapid and the deflection in a direction lengthwise of the target strips being relatively slow, means for developing control wave energy for controlling the time period of formation and suppression of the individual electron beams, said beam suppression periods being related to the time duration required to traverse each color responsive series of the target in the direction of rapid motion of the target strip corresponding substantially to of the time required to traverse the color strips forming each series, where represents the number of component colors in the additive series, means to develop three phase-shifted variations of the control energy to control the developed electron beams with the phase shift between each 24 being 21/0 where 0 again represents the number of component colors and 21 represents the time to traverse one series of color response strips, and means for applying modulation signals to modulate the electron beams to produce color response in the component color response areas of the targets in accordance with the modulation signals applied so that signal modulation beams impact 7 the strips in sequence. a

' 16. In a multi-color television system wherein is included an electron tube having a target area formed as a repeating series of elongated strips adapted to luminesce, under electron beam im pact,'in the several component colors of an additive color system, and wherein a plurality of electron beams equal in number to the number of component color producing strips in the series are developed with each electron beam being adapted to impact the target, each from a different angle relative to each other and along a path at an acute angle to a normal to the target area, the system for producing additive color imdeflected electron beams, means for shifting the 7 phaseal relationship of the deflected wave energy, pulses developed relative to each other through an angle of 21r/C where 0 represents the number of component colors in the multi-color series, so that the plurality of electron beams become active in sequence to impact the target area while traversing strips of one character in the series and remain inactive during remaining periods of deflection transverse to predetermined component color image producing areas of the target whereby different sections of the target are impacted by difierent electron beams and color response indications, means to modulate each electron beam by color signals of one color component only for each beam, and means to synthesize periods of 'beam formation and modulation in desired color so that color responses in the several colors are appropriately coordinated.

17. In a tricolor additive television system, a cathode ray image producing tube having therein a target area formed from a repeating series of luminescent strips adapted to luminesce in each till of three component colors and having means to develop electron beams of a number corresponding to the number of component colors of the target area, each of said beams being of a width substantially equal to the width of each strip and of a length substantially equal to the width of three color strips, means for deflecting each of the electron beamsrelative to the target in bidimensional path traces with a rapid motion of deflection being transverse to the length of the strips of the target and the beam long dimension and with a, relatively slow motion of deflection in a direction lengthwise of the strips and of the long dimension of the beam, means for developing control pulses of energy for controlling in sequence the suppression and the formation of the said electron beams so that during the simultaneous deflection of all of the electron beams one only is instantaneously active upon one component color response section of the target and the sequence of activity and suppression is c0or- 25 dinated with a number of color response strips in the target and means for applying modulation signals to the independent electron beams so that the plurality of electron beams are modulated by signals representative of one component color for time periods during which action of the related component color target area is occurred.

18. In a tricolor television system wherein is included an electron tube havin a target area formed as a repeating series of elongated strips adapted to luminesce, under electron beam impact, in the several component colors of a tricolor additive system, and wherein av plurality of electron beams equal in number to the number of component color producing strips in the series are developed with each electron beam being adapted to impact the target, the method of producing additive color images which comprises deflecting each of the developed electron beams across the laminated target area in a direction transverse to the direction of the elongated strips. generating controllin wave energy for controlling the time of formation and suppression of each of the deflected electron beams. shifting the phaseal relationship of the deflected wave image so that the plurality of electron beams become active in sequence upon impacting the target area while traversing strips of one character in the series and remain inactive during remaining periods of deflection transverse to predetermined color image producing areas of the target whereby different sections of laminations are impacted by different electron beams and color response indications on the laminations will appropriately coordinate.

l9. In a tricolor television system wherein is included an electron image producing tube having a tar et area formed as a repeating series of eiongated strips adapted to luminesce. under electron beam impaet, in the component colors of an additive tricolor system. and wherein an electron beam is developed within the tube for scanning the component color light producing strips along paths transverse to the length, the method of producing cyclically additive color images which comprises supplying modulation signal energy in each of the selected component colors to modulate the developed electron beam, a plying biasing voltages normally tending to nullify the modulation effect of si nals supplied, generating control wave ener y pulses, producing from the control wave energy pulses a plurality of phase shifted variances thereof with the phase shift between the ifferent signals being substantially 120 and utilizing the phase shifted variances in. the control wave energy pulses for sequentially overcoming the biasing effect on each of the impressed component color modulation signals so that received signals sequentially modulate the developed electron beam and cau e the development of luminescent effects on the target area which represent color images in accordance with the ap lied signal energy.

20. In a tricolor television system wherein is included an electron image producing tube having a target area formed as a repeating series of elon ated strips adapted to luminesce. under electron beam impact, in the several component colors of an additive tricolor system. and wherein an electron beam, is developed within the tube forscanning the component color light producing strips along paths transverse to the length, a,

system for producing cyclically additive color images which comprises signal input means for supplying modulation signal energy in each of the selected component colors to modulate the developed electron beam, a plurality of biasing voltage sources connected with the signal input for normally tending to nullify the modulation effect of signals supplied, a control wave energy generating source for producing control pulses, means for producing from the control wave energy pulses a series of three phase shifted variances with a substantially like phase shift between each of the difierent pulses and means for supplying the separate phase shifted variances of the control wave energy pulses to the signal input for sequentially overcoming the biasing effect on eachof the impressed component color modulation signals so that the input signals sequentially modulate the developed electron beam and develop luminescent effects on the target area in accordance with the color representations portrayed by the applied signal energy.

21. In a color television system wherein a color image appears on the target area of an electron tube, which target is formed as a repeating series of elongated strips adapted to luminesce, under electron beam impact, in selected and chosen component colors of an additive color system, and wherein a plurality of independently controllable electron beams equal in number to the number of component colors of the additive system are developed and arranged to be focused upon and to impact the target each from a different angle relative to each other and each at an acute angle relative to a normal to the target, the combination for developing additive color images which comprises means for relatively rapidly deflecting each of the developed electron beams across the target area in directions transverse to the direction of the elongated strips and relatively slowly deflecting each beam longitudinally of the strips to scan an image raster area, means for deriving energy of a frequency related to the rapid defiection frequency and for generating from such energy a plurality of distinct controlling wave energy pulses equal in number to the number of separate electron beams for controlling the time periods of formation and suppression of each of the developed electron beams, phase shifting means to control the phase relationship of each of the control wave energy pulses relative to each other so that the several electron beams become active in predetermined sequence and for predetermined'time periods to impact the target area while traversing strips of one character only in the series and remain inactive during remain ing periods of deflection transverse to predetermined other color image producin areas of the target, means for supplying modulating control signals for modulating each electron beam by image signals representative of one only of the selected component colors, means for synthesizing the periods of signal modulation with periods of beam formation and the relationship of the target area impacted by the electron beams to provide color response indications on the target area coordinated with the signal modulation.

22. In a multi-color television system wherein is included an electron tube having a target area formed as a repeating series of elongated strips adapted to luminesce, under electron beam impact, in the several component colors of an additive system, and wherein a plurality of electron beams equal in number to the number of component color producing strips in the series are developed with each electron beam being adapted to impact the target, each from a different angle relative to each other and each along a e 27 .path at an acute angle to a normal to the target area, the system for producing additive color images which comprises means for simultaneously and relatively rapidly deflecting each of the developed electron beams across the strips of the target area in a direction transverse to the elongated dimensions of the elongated strips and relatively slowly longitudinally of the strips to scan an image raster area, means for generating controlling wave energy pulses for controlling the time periods of formation and suppression of each of the deflected electron beams, means for shifting the phaseal relationship of the deflected wave energy pulses developed relative to each other through an angle of 21r/c, where c represents the number of component colors'in the multi-color series, so that the plurality of electron beams become active in sequence to impact the target area while traversing strips of one character in the seriesand remain inactive during remaining periods of deflection transverse toother predetermined component color image producing areas of the target whereby different sections of the target are impacted by different electron beams and color response indications, means to modulate each electron beam by color signals of one color component only for each beam, and means to limit the periods of signal modulation of each electron beam so that signal controlled beam modulation occurs only at time periods when the said modulated beam impacts sections of the target producing luminescent color effects corresponding to those initiating the modulation.

23. A tricolor additive television system including a cathode ray tube. having a target area formed of repeating series of elongated strips adapted individually to luminesce under electron beam impact, in each of a plurality of primary colors of an additive color sequence, means for developing three independent electron beams and for directing the said electron beams toward the target area along a plurality of projection paths each angularly disposed relative to each other and each at an acute angle to a normal to the impacted target, means for deflecting each of the said electron beams relative to the target along bidirectional paths with the deflection in a direction transverse to the strip elements of the target being relatively rapid and at a substantially uniform rate and the deflection in a direction lengthwise of the target strips being relatively slow, means for developing control wave energy for alternately controlling the time period of formation and suppression of the individual electron beams, said beam suppression periods being for time periods of the order of twice the beam formation periods where the beam formation period corresponds substantially to the time required to traverse-one of the color strips forming each series, means to develop three substantially 120 phase-shifted variations of the control energy to control in sequence the formation periods of each of the electron beams, and means for applying modulation signals to modulate the electron beams to produce color response in the component color response areas of the targets, in accordance with the modulation signals applied so that signal modulation beams impact the strips in sequence.

24. A color television system comprising an electron tube having a built-up target area formed as a repeating series of strip-like elements with the target elements of each series being of materials adapted to fluoresce upon electron impact in each of a predetermineil Iillmber of com- 28 ponent colors to provide additive color images, means to modulate the deflected electron beam in sequence under control of video signals representative of each of the selected component colors of the additive color system to provide intensity control of each color response, means for developing beam control energy having a predetermined relationship to the line frequency at which produced color images are to be deflected to limit the periods of active beam response, means to generate from the control energy a series of control pulses out of phase with respect to each other by predetermined amounts and means for utilizing the said pulses to control the time periods during which signals representative of the several component colors are applied to control the image production.

25. A color television system including an electron tube having included therein a target area formed from a plurality of series of strip-like elements each of a width which is a fractional part of one dimension of each image point to be produced and wherein the plurality of strips are collectively arranged to produce, under excitation by an electron scanning beam, light cheats in each of a predetermined number of component colors to provide additive color images, means to deflect and concurrently modulate the electron beam under the sequential control of separate video signals equal in number to and representative of each of the selected component colors of the additive color system to provide an intensity control of the lightefiects produced in each color, means for deriving electron beam control energy having a predetermined relationship to the instantaneously produced color image points, means to derive from the produced control energy a plurality of controlling signals to determine the time period during which the sep arate'video signals are effective individually to control and modulate the said electron beam.

26. A color television system comprising an electron tube having a target area formed as a repeating series of strip-like elements arranged to be impacted by an electron beam developed within the tube and at time periods of electron beam impact to initiate light effects at the point of impact in a predetermined number of component colors to provide collectively additive color images, means to deflect the electron beam to cause it to trace a scanned raster in a linefor-line manner on the target, each line trace of the raster being substantially in a direction transverse to the long dimension of each striplike element, means to modulate the deflected electron beam under the control of video signals representative of each of the selected component colors of the additive color system so as to provide intensity control of each color response, means for developing concurrently with the electron beam deflection a series of control signals bearing a predetermined relationship to the electron beam deflection in each line as it forms the raster, and means to utilize the produced control signals to limit the periods of electron beam modulation by the individual signals and thereby effect a rapid sequential switching of the beam modulation control by the several component color signals during each traverse of each line of the scanning beam traces forming the image raster so that for each scanned line trace of the image raster light effects representing the produced image in each selected component color are developed for each scanned element.

27. Electronic color television apparatus com- 29 prising a cathode ray tube having a target area and'having developed therein an electron scanning beam arranged to be deflected in a bidirectional pattern relative to the target area to trace an image raster comprising a multiplicity of elongated coated beam-impact strips each of subelemental width as compared to one dimension of each image point to be produced and each secured to form a part of the target area, each of said impact strips when activated by the impacting electron beam being adapted to cause the production of light in one of a plurality of selected component colors of an additive color system and collectively arranged to form substantially uniforrnly repeating sequences of color response areas so that at least one response in each selected component color is brought about by electron beam upon its impacting each elemental area of image recreation on the image raster, means to deflect the developed electron beam relative to the beam impact strips to trace the image raster in a series of substantially parallel lines with the direction of line production being substantially transverse to the direction of strip length, means for developing electron beam control signal during the traverse of the scanning 30 beam along each direction of line traverse and transverse to each strip of the target, means to utilize the developed beam control signal energy to limit the instantaneous intensity modulation of the electron beam to the control of a single component color signal only which is representative of one related and selected component color.

ALFRED N. GOLDSMITH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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