US2745033A - Display surface for color television tube - Google Patents

Display surface for color television tube Download PDF

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US2745033A
US2745033A US399753A US39975353A US2745033A US 2745033 A US2745033 A US 2745033A US 399753 A US399753 A US 399753A US 39975353 A US39975353 A US 39975353A US 2745033 A US2745033 A US 2745033A
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strips
color
grid
screen
electrodes
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Ernest O Lawrence
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Chromatic Television Laboratories Inc
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Chromatic Television Laboratories Inc
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Priority to CA553317A priority Critical patent/CA553317A/en
Priority to BE534344D priority patent/BE534344A/xx
Priority to DENDAT1050367D priority patent/DE1050367B/de
Priority to NL193469D priority patent/NL193469A/xx
Priority to IT529461D priority patent/IT529461A/it
Priority to SE526053A priority patent/SE160882C1/xx
Application filed by Chromatic Television Laboratories Inc filed Critical Chromatic Television Laboratories Inc
Priority to US399753A priority patent/US2745033A/en
Priority to FR1137763D priority patent/FR1137763A/fr
Priority to GB36999/54A priority patent/GB777868A/en
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/16—Picture reproducers using cathode ray tubes
    • H04N9/22—Picture reproducers using cathode ray tubes using the same beam for more than one primary colour information
    • H04N9/26—Picture reproducers using cathode ray tubes using the same beam for more than one primary colour information using electron-optical colour selection means, e.g. line grid, deflection means in or near the gun or near the phosphor screen

Definitions

  • This invention relates to cathode-ray tubes for displaying-television images in natural color. Specifically, it relates to display surfaces for tubes of the type wherein three component colors which, additively, produce white light when mixed in appropriate proportions, are displayed in succession so rapidly that the eye views them as if simultaneous. The change from color to color is accomplished by directing a beam of cathode-rays successively to elemental areas of phosphors emissive of the different primary colors chosen, deflection being accom that of the display screen and closely adjacent thereto.
  • each set is connected, but the two sets are mutually insulated so that alternate electrodes are of the same potential while different potentials may be applied to the two sets.
  • the spacing of adjacent electrodes is of the order of magnitude of one picture element as defined above and the electrodes are sub stantially parallel to the phosphor strips on the screen.
  • the strips are so spaced with relationtov the electrodes that a cathode ray beam, scanning the target area occupied by the display screen and the color controlgrid and centered between any pair of electrodes of the two sets of the grid will also be substantially centered on a phosphor strip emissive of light of one of the three component colors, preferably green; i. e., the stripsjof phosphor emissive of this one color are electroroptically centered behind the mid-point between each pair of impact and excite a phosphor of a single 'color only,
  • Such constriction can be accomplished by a mask, which can be either part of or sep-- arate from grid electrodes, but preferablyit is-accomplished by utilizing the grid electrodes ascomponents "nited States Patent 2,745,033 Patented May 8, 1956 "ice of electron lenses having, as an additional element, a film or electron permeable layer of conducting material, suchas aluminum, deposited over the phosphor surface.
  • An electron beam may be developed by a conventional approximately four times that of the color control grid with respect to .the, cathode, all electrons entering between the electrodes of any pair will be focused, in the dimension normal to the length of the grid electrodes, to a narrow line whose length is substantially equal to the diameter of the beam but whose width is only a small fraction thereof, so that practically the entire energy of the beam is concentrated in a small area at the focus.
  • Tubes of this type can be used to display color television images transmitted by any of the conventional systems, whether the system used be designated as field sequentialf? line sequential, dot sequential or simultaneous, the designation referring to whether information relative to the respective colors is transmitted se-' quentially or simultaneously.
  • N. T. S. C. National Television Systems Committee
  • tubes of the character herein considered have only a single electron gun'and only one (or at most two) of the component colors can be displayed at any one instant, simultaneous signals must be broken down into dot sequential signals fordisplay upon the screen.
  • therelative potentials of the electrodes composing the grid are alternated rapidly about the mean potential'thereof, so that the beam falls on the colors successively in the order red, green, blue, green, red, etcQ'at a frequency of several million cycles per second.- Over'intervals of one color cycle at this frequency the'eye integrates the light of each component color-over the time during which it is received, so that the apparent intensity which it registers is pro portional not only to the intensity of the electron beam itself but also to the period during which it falls upon any one'color.
  • the electrical capacity between the two sets of electrodes of the color grid is relatively high, and in order tov achieve the necessary deflection of the beam with a moderate amount of powerin the deflecting circuit, it is practically necessary to connect the sets of electrodes in a resonant oscillating circuit, tuned to the frequency 'of the color deflection.
  • the relative potential of the two sets'of electrodes varies substantially in accordance with a sine law. Accordingly, the velocity of the spot of illumination produced by the electron beam, as itis deflected by the color control potentials in the direction transverse to the long dimension of the phosphor strips, is constantly varying. To produce the proper color balance the beam should impact a strip of each color through one-third of each cycle of the color sequence, or as nearly as possible, for
  • the beam ideally, should fall on the green strip for 60 electrical degrees out of each half cycle, or 30 electrical degrees on either side of the undeflected position. Since the amount of deflection is proportional to the voltage, which varies sinusoidally, and since the sine of 30 is equal to one-half, the width of the green strip should be equal to one-half of the total color deflection of the beam at its point of impact if pro-per color balance is to be achieved and the television image reproduced with its true color values.
  • the criterion just statcd is an ideal which assumes that the width of the line focus of the beam approaches zero. In practice, although small, its width is finite, and during the time when it is traversing the junction between adjacent strips it will excite the emission of two colors. In order to prevent color dilution it is therefore advisible to blank out the beam during the transition period. If the deflection of the beam is not in the proper proportion to the width of the intermediate strip, balance can still be achieved by prolonging the blanking interval, thus achieveing the balance at the expense of a diminution in the total light emitted by the screen.
  • the objects of this invention are to avoid the difliculties above enumerated; i. e., to provide a display surface for tubes of the character described with which color balance may be substantially maintained over the entire surface of the display screen irrespective of the system of color transmission employed; to provide a display screen which permits the presentation of true, color values with minimum periods of blanking of the beam; to provide a display surface for use with a single gun televsion tube and hence avoid all problems of registration as, between various components of a color television image; to provide a color tube having a display screen which will deliver maximum light intensity for a given electron current in the cathode-ray beam; to provide a display screen having the above stated characteristics which can be manufactured economically and sold at a reasonable price, and especially to provide a tube which will display blackand-white images of uniform tone throughout the screen without the necessity of gating the signal.
  • the screen of the present invention corresponds to that described above, but is characterized by the fact that the strips which are electro-optically centered midway between adjacent electrodes are Wider at their ends than in their central portions.
  • the strips which emit green light which are shaped in the manner described, although this is for reasons apart from the present invention and color balance can be achieved regardless of which color is emitted by the phosphor so disposed.
  • the strips which are electro-optically centered directly behind the electrodes of the grid are correspondingly narrower at their ends and wider in their middle portions.
  • the electrodes and the strips of phosphor may be disposed either in the direction of the shorter or the longer dimension of the screen and preferably the widths of the strips at their ends are substantially uniform.
  • the outward flare of the intermediate strips from their centers to their ends may be made rectilinear, and such a conformation of the strips will give improved results with any degree of scanning deflection; preferably, however, the sides of the strips are curved, so that the outward flare of the intermediate strips increases towards their ends, or the curve may be approximated by a succession of straight lines.
  • Fig. l is a schematic diagram, in longitudinal section, of a cathode-ray tube embodying the instant invention.
  • Fig. 2 is a face view of the central portion of a display screen embodying the invention, together with the color control electrodes controlling the portion of the screen shown, thewidths of the strips of various phosphors comprising the screen being very greatly exaggerated in comparison with their lengths.
  • Fig. 3 is a fragmentary cross section through the display screen and the grid electrodes, in a plane perpenducular to the latter.
  • Fig. 4 is a series of graphs illustrating the optimum widths of the intermediate strips of phosphor in terms of the percentage difference in the widths of these strips from the minimum width of the strip crossing the center of the screen.
  • Fig. 5 is a schematic showing of the form of the display surface, illustrating the directions in which the variation of intermediate strip-width is plotted in the various graphs of Fig. 4.
  • the tube schematically shown in Fig. l is conventional except for the color control and display surfaces. It comprises the usual evacuated envelope 1, generally of I funnel shape, with the window 2 through which the dis- (indicated by the dotted line 11) with respect to the axis of the tube.
  • the path of the beam from a center of deflection indicated by point 13 is straight, so that its angle of incidence at the color control structure adjacent the viewing screen 5 is equal to the angle 6 included be tween the beam and the tube axis. T his assumption simplifies the description but it is the angle of incidence which is actually important.
  • the color control grid is mounted closely adjacent to the screen 5. It comprises two sets of electrodes, designated respectively as 15 and 15. In the present instance these electrodes are Wires, tightly stretched on a suitable supporting frame, not shown here since structure of the grid is not a feature of this invention.
  • This wires 15 are interconnected to a common lead 17 which is brought out through a suitable seal in the walls of the envelope 1.
  • the wires 15' are similarly connected to a lead 17.
  • the total number of wires used will be from 400 to 500 or more, one-half being connected in each set.
  • the spacing between adjacent wires will therefore be of the order of magnitude of one picture g element as displayed upon the tube.
  • these wires are so disposed that they run vertically when the tube is in normal viewing positon, but this is not an essential feature of the invention; other factors may make a horizontal disposition preferable.
  • the screen comprises a transparent base plate 19, on which is deposited a layer 21 of phosphors, and, in the tube shown, the phosphor layer is covered by a thin, electron-permeable layer 23 of conducting material, preferably aluminum.
  • the connection 25 is brought out from the'layer 23 through the walls of the tube.
  • the layer 21 of phosphors is composed of strips of different phosphors, emissive, upon impact by the electron beam, of light of the different component colors which additively produce white.
  • the phosphors will hereinafter'be referred to as being of the color of the light as emitted, although, in general, when viewed by reflected light, all will appear very nearly white.
  • Fig. 2 The arrangement of the phosphors is shown in greatly exaggerated form in Fig. 2. This exaggeration is necessary because the actual shape of the strips could not be made apparent in a patent drawing.
  • the particular tube shown has a 20-inch screen, i. e., a viewing area measuring 20 inches across its longest diagonal, and has an aspect ratio of 3:4, with the grid wires disposed vertically, the length of the strips will be 12 inches.
  • the theoretical number of elements per line actually displayed is about 435, so there will be this number of inter-electrode spaces across the 16 inch width of the screen, and the number of phosphor strips will be double this figure or 870.
  • the average width of each strip in this instance will be less than 20 mils, making the ratio of length to average width over 600:1.
  • To show strips of this aspect ratio is obviously impractical,.and therefore the width of those shown in Fig. 2 is exaggerated in comparison with their length. Since this invention is concerned with the ratio of the width of each strip at its center to its width at its ends the actual aspect ratio illustrated is unimportant as long as the fact of the exaggeration of the showing is kept in mind.
  • Fig. 2 the lines 15 and 15 represent the electrodes of the sets similarly marked in Fig. 1.
  • application Serial No. 265,366, now United States Patent No. 2,669,675, dated February'16, 1954 if the average potential of the two sets of electrodes with respect to the cathode of the electron gun be maintained at approximately 25% of the potential between the film 23 and the cathode, the interspace between each pair of grid electrodes becomes the aperture of a cylindrical electron lens which converges the beam from :the gun to a focus at the plane of impact with the screen.
  • Phosphor strips 27 are electro-optically centered under the center of each aperture formed by the grid.
  • the United States patent above identified defines the term electro-optic-ally centered and describes the relative placement of focusing electrodes and strips required to accomplish it.
  • the term means that when no potential diiference is applied between the electrodes 15 and 15' and the beam is so deflected that it is centered on the aperture between such a pair of electrodes, the focal point will be centered upon the strip in question. If the screen be viewed through the grid with the eye at the center of deflection, strips 27 will not appear to be alined with the centers of the aperture, since the focusing field bends the beam passing through the grid toward the screen to .a degree which depends upon the angle of deflection. The center of the aperture is therefore neither perpendicularly in 'front of the centers of the strips throughout the field nor are they optically centered with respect thereto.
  • the center of the aperture is therefore neither perpendicularly in 'front of the centers of the strips throughout the field nor are they optically centered with respect thereto.
  • the strips 27 are characterized by the fact that they I are materially broader at their ends than they are at their central portions. Between each pair of strips 27 there is a strip of one of the other two phosphors, strips 29, of the red phosphor, being electro-optically centered'under each of the electrodes 15 and strips 31, of the blue phosphor, so centered under each of the electrodes 15', so that, considered in order in the direction of scanning deflection of the beam, the colorcycle is red, green, blue, green, red, etc. termined by that of the strips 27, their shape being such that they are contiguous to the intermediate strips 27 throughout their lengths.
  • the sensitivity of the beam, to deflection by electric fields established between the two sets of electrodes of the grid, varies with its angle of incidence to the grid, being greatest at maximum deflection and least when its angle of incidence 0 is zero.
  • the color-control deflection is always in a plane normal to the grid wires, and the variation in deflection sensitivity varies with both the angle a the component of the angle of incidence 0 parallel to the grid wires, and the angle 5, perpendicular thereto.
  • the angles are related by the equation:
  • Vh is proportional to the time spent by the beam in traversing the deflection field and can be written:
  • the grid deflection is proportional to the electric charge on grid wires produced by deflection voltage VI) and is inversely proportional to the [3 plane component of beam velocity, Vs, at the grid. Therefore cos 6 m cos B (S) q: /2C VD where C is the capacity between adjacent electrodes per cm. length of electrode of one polarity.
  • Vn/ V1 is an operating parameter which may be chosen as desired, and is uniform throughout the target area. If the spacing of the grid wires is also uniform the first term on the right-hand side of the equation becomes a constant. It is convenient to treat it as such, since as is shown in the copending applications cited, variation in grid wire spacing (where it is resorted to in order to correct for beam refraction) is always small, is preferably accomplished in steps, and is in any event a minor factor in the equation.
  • the quantity which is actually desired for the purposes of the present invention is the relative deflection sensitivity Sr, which is the ratio of the sensitivity at any point of the target to that at the center, where 0:0. If the electrode spacing is constant,
  • the location indicated by the reference character 41 which is substantially at the point of intersection of the sensitivity curves, marks the maximum relative sensitivity with a 90 tube, substantially constant along the edges of the screen.
  • Points 43 and d3 indicate maximum sensitivity for deflection along the horizontal screen axis for the same tube.
  • Points 45 and 47 indicate the loci of maximum sensitivity for vertical scanning angles, on the vertical axis and at the corners of the screen respectively for a 72 tube while points 49 and 49' indicate maximum sensitivity for deflection along the horizontal screen axis.
  • the widths of the strips 27 should vary with variations in the angle or in accordance with the values plotted in Fig. 4. It will be seen, however, that for a 72 tube the graph 51, comprising two straight lines, nowhere departs from either curve 33 or curve 35 by more than 3.5%. Therefore a very satisfactory approach to the optimum shape of strip can be achieved by giving the edges of the strips a straight-line contour, all of the strips 27 being of the same shape and dimensions, it being understood that the widths of the strips vary with length in proportion to the ratio of the values plotted to its minimum value. The errors will be least in the zones where ,8 is about 22% or about of the total horizontal deflection. Alternatively, strips of two, three or more different contours can be used in successive zones, from the center outward. This will be necessary in any case with tubes using wider deflection angles if the suggested tolerances are tobe maintained. It
  • the strips 27 and 31 may be made only slightly more than l/z the width of strips 29 at their ends.
  • the actual size of the spot that can be produced is also a factor.
  • the focusing potentials which theoretically should reduce the spot to a geometrical line, without width, actually give a spot width of about 3 mils, owing to scattering of electrons in the metal layer and the phosphor, scattering of light in the phosphor, and to a minorextent, electron lens aberrations.
  • the convergence is about 1.165, which means that the theoretical width of the spot is 16.5% of the width of the aperture between the electrodes.
  • the spacing of the grid wires is 30 mils on centers, and the wires are 6 mils in diameter, this gives a theoretical spot size of .165 X24 mils or about 4 mils.
  • the spot size will vary between 3 mils atthe center and 7 mils at the corners of the screen.
  • the maximum spot width With a 90 tube the maximum spot width, with the same electrode spacing, would be 9 mils if the maximum constriction is at the center of the screen.
  • the desideratum is that the dwell on the strips 27 shall be uniform throughout the picture field. Therefore the optimum method of employing the invention is to compute the proportional widths of the strips 27 on the basis of Equation 11 or the curves of Fig. 4 and then add to the widths thus computed the width of the spot.
  • the width added may be either graduated to accord with the actual width at various angles of deflection, or it may be the maximum spot width which is added throughout the entire length ofthe strip. Iii the latter case if the blanking period is adjusted to prevent the spot'falling on two phosphors simultaneously at the positions of maximum spot size no overlap will occur at any part of the field.
  • the dwell on the strips 27 will be uniform throughout the picture field to within the degree of approximation to which the strip widths approach their theoretical values. This will be so regardless of the amplitude of color deflection. If this amplitude is too low there will be some color dilution and the color balance will tend toward the green, if the amplitude is too great there will again be some dilution and the color balancewill tend toward the purple. By proper adjustment of deflection amplitude an accurate color balance and minimum blanking period can be attained.
  • Equation 11 is no longer a constant, but must be recomputed for each zone in which the spacing is varied. If the width of the color cells is varied the variation mustbe confined to the strips 29 and 31.
  • Thescreen in either case may be constructed by machining metal masks to the required contour and moving them, step-by-step, across a surface from which a master pattern is to be prepared, for example a silk screen which is to form a wax stencil, or a photographic plate which is exposed line-by-line.
  • a more elegant method of preparing the screen is to construct a target using a grid of the same form as is to be empoyed in the commercial tubes, but to replace the screen with either a photographic plate or a monochrome fluorescent screen.
  • This target is placed in a demountable tube having the same structural parameters as those in which the targets are to be used. Focusing voltage and scanning deflection ratios are adjusted to optimum values. The color deflection voltage, however, is reduced so that the excursion of the spot is limited to the desired width of the strips 27 at the positions of maximum deflection sensitivity.
  • aphotographic plate is used as the target the beam itself accomplishes the exposure. If a fluorescent screen is used it is photographed in the usual manner. In the latter event great care must be exercised to ensure that aberrations due to the tube window and the screen itself do not cause distortion. In either case a master negative is produced of the strips 27, including all corrections for refraction, deflection sensitivity and spot size. Duplicate negatives on glass provide patterns from which the stencils or other printing media for the strips 29 and 31 may be prepared by blanking out alternate white lines.
  • the amplitude is reduced to 26 mils, increasing the dwell on the green to nearly 70 out of the half cycle and reducing the dwell on each or the others to 55.
  • the 15% difference in deflection sensitivity increases the green by a factor of 1.20 and reduces the other two colors by 9% each. From another point of View, the green, instead of being equal in value to each of the other two color components, is about 27% greater, which is enough to be unpleasant to the viewer.
  • the width of the green strips at the center of the field will be reduced from 15 mils to somewhere between 12.6 mils and 13.4 mils, and nominal value being 13 mils. Taking the maximum value of 13.4 mils, the dwell on the green will be 62 and that on the other two 59 each. The green is therefore only 5% greater than the other two, a 51l reduction in unbalance. Since the small amount of unbalance varies gradually over the screen it is practically unnoticeable. Therefore, although the complete correction is to be preferred even rougher approximations than those here suggested will give materially better resuits than the use of straight phosphor strips.
  • the screen To present the proper illusion of color the screen must be viewed from a suflicient distance so that the spots of illumination from adjacent color cells merge.
  • the total average illumination from adjacent color cells remains sensibly the same and the only effect of the inaccuracy, as far as color balance is concerned is a displacement of the red and blue elements from their proper positions by one mil, which is undetectable.
  • the effect may be somewhat greater if the blanking period is reduced to its theoretical minimum.
  • the blanking pulses will be displaced from their theoretically proper positions by electrical degrees and it might be expected that this would have serious effects.
  • Such effects are reduced, however, by two factors; first, the spot is not of constant intensity throughout its cross section, but is brighter in the center, and second, the pulses used for blanking the spot have a finite rise time.
  • the center or green strips will be about 12 mils wide at their centers without the barrel correction and 12.012 mils wide when the correction is made, while the contiguous strips of red and blue emitting phosphors will be 17.988 mils wide at their centers.
  • the only observable effect of employing the barrel correction together with the present invention is the slighttbowing of the outer strips of'the' phosphor pattern; thebarrel correction is so small as to be completely masked by the correction herein described as far as any individual strip is concerned. Even the outward bowing of the strips is so slight as to be almost invisible unless compared with a straight edge.
  • the photo graphic method of forming the screen is employed, as described above, both the correction of color-cell spacing and of deflection sensitivity. are accomplished simultaneously. I
  • the variations from color-cell to cell are extremely minute; smaller, on the, average, than the tolerances that can be met in commercial tube manufacture.
  • the cell-to-cell variations are cumulative.
  • the intent of the present invention as well as that of the companion appli cation is to compensate the cumulative variations within the limits of manufacturing tolerances.
  • To build a tube exactly conforming to the equations set' forth herein would require a degree of precision far beyond that normally attained in tube manufacture. Tubes wherein the cumulative variations intended to be compensated are less or, at least no greater than the individual manufacturing tolerances, thus substantially conforming to the equations given, can be manufactured economically in quantity using presently available. techniques.
  • a cathode-ray tube for displaying television images in natural color which includes an electron gunfor directing a beam of cathode-rays toward a target area within said tube over which area said beam is adapted to be deflected in two dimensions to trace a raster and.
  • a substantially planar color control'grid comprising two interleaved sets of linear electrodes the interspaces between which are of the order of magnitude of one elemental area of the television images to be reproduced: a display screen defining said target area comprising a base plate mounted in a plane substantially parallel and adjacent to said target area, and a coating on said display screen comprising strips of three diiferent phosphors respectively emissive on electron impact of light ofthree component colors additive to produce white, the strips of one of said phosphors being elect ve-optically centered behind the interspaces between the electrodes of said grid and being "wider at their ends than at their central portions and the strips of the other two of said phosphors being electro-optically centered respectively behind the electrodes of said two sets and forming with said first-mentioned strips a substantially continuous coating.
  • a cathode-ray tube for displaying television images in natural color which includes an electron gun for directing a beam of cathode-rays toward a target area within said tube over which area said beam is adapted to be deflected in two dimensions to trace a raster and a substantially planar color control grid comprising two' interleaved sets of linear electrodes the interspaces between which are of the order of magnitude of one elemental area of the television images to be reproduced: a display screen defining said target areacomprising a base plate mounted in a plane substantially parallel and adjacent to said target area, and a coating on said display screen comprising strips of three different phosphors respectively emissive On electron impact of light of three component colors additive to produce white, the strips of one of said phosphors being electro-optically centered behind the inters'paces between the electrodes of said grid and being wider at their ends than at their central portions andthe strips of the other two of said phosphors beingelectro-optically centered
  • a cathode-ray tube for displaying television images in natural color which includes an electron gun including an electron emitting cathode for directing a beam 'of cathode-rays toward a target area within'said tube over which area said beam is adapted to be "deflected'in'two dimensions to trace a raster and a substantiallyplanar color control grid comprising two interleaved sets of linear electrodes the interspaces between which are of the order of magnitude'of one elemental-area of the television images to'be reproduced; a display screen defining said target area comprising a base plate mounted in a plane substantially parallel and adjacent to saidtarget area, and a coating on said display screen comprising strips of three difierent phosphors respectively emissive onelectron impact of light of three component colors additive to produce white, the strips of one of said phosphors being electro-optically centered behind the interspaces between the electrodes of said grid and widths of said strips varying along the lengths thereof so that the
  • a cathode-ray tube for displaying television images in natural color which includes an electron gun including an electron emissive cathode for directing a beam of cathode-rays toward a target area within said tube over which area said beam is adapted to be deflected in two dimensions to trace a raster and a substantially planar color control grid comprising two interleaved sets of linear electrodes the interspaces between which are of the order of magnitude of one elemental area of the television images to be reproduced; a display screen defining said target area comprising a base plate mounted in a plane substantially parallel and adjacent to said target area, and a coating on said display screen comprising strips of three different phosphors respectively emissive on electron.
  • the strips of one of said phosphors being electro-optically centered behind the interspaces between the electrodes of said grid and increasing in width progressively from their central portions outwardly to their ends substantially by increments cos d tan?
  • a cathode-ray tube for displaying television images in natural color which includes an electron gun including an electron emissive cathode for directing a beam of cathode raystoward a target area within said tube over which area said beam is adapted to be deflected in two dimensions to trace .
  • a raster and a substantially planar color control grid comprising two interleaved sets of linear electrodes the interspaces between which are of the order of magnitude of one.
  • a display screen defining said target area comprising a base plate mounted in a plane substantially parallel and adjacent to said target area, and a coating on said display screen comprising strips of three different phosphors respectively emissive on electron impact of light of three component colors additive to produce White, the strips of one of said phosphors being electro-optically centered behind the interspaces between the electrodes of said grid and increasing in width from the centers to the ends thereof substantially in proportion to the increase of said beam in sensitivity to deflection by said grid with increase in angle of incidence thereto, and strips of the other two of said phosphors disposed alternately in the spaces between said first described strips.
  • a cathode-ray tube for displaying television images in natural color
  • an electron gun including an electron emissive cathode for directing a beam of cathode rays toward a target area within said tube over which area said beam is adapted to be deflected in two dimensions to trace a raster and a 1 5 substantially planar color control grid comprising two interleaved sets of linear electrodes the interspaces between which are of the order of magnitude of one elemental area of the television images to be reproduced;
  • a display screen defining said target area comprising a base plate mounted in a plane substantially parallel and adjacent to said target area, and a coating on said dis play screen comprising strips of three different phosphors respectively emissive on electron impact of light of three component colors additive to produce white, the strips of one of said phosphors being electro-optically centered behind the interspaces between the electrodes of said grid and increasing in width from the centers to the ends thereof substantially in proportion to the sum of the increase in sensitivity of the beam
  • a display screen for cathode-ray tubes for producing television images in color and employing lens-grids comprising a multiplicity of generally parallel linear conductors for establishing a system of electron lenses adjacent to said display screen, comprising a supporting base, and a phosphor coating on said base consisting of generally parallel strips of three dilferent phosphors respectively emissive on electron impact of light of three component colors additive to produce white light and arranged in a repeating pattern, alternate strips being wider at the end portions than at the central portions thereof and the intervening strips being wider at the centralportions than at the ends thereof.
  • Target structure for color television display tubes comprising a grid formed of two interleaved and mutually insulated sets of generally parallel elongated linear conductors, the conductors of each set being interconnected, a base mounted adjacent to said grid, a coating on said base consisting of three different phosphors which are respectively emissive on electron impact of light of different colors additive to produce White light, said phosphors being disposed in a repeating pattern of strips generally parallel to said conductors and the number of strips being twice the number of int rspaces between said conductors, alternate strips being Wider at the end portions than at the central portions thereof and the intervening strips being wider at the central portions than at the end portions thereof, and a conductive coating deposited on said phosphor coating.
  • Target structure for cathode-ray tubes adapted for displaying television imagesin substantially natural color comprising a color-control and lens-grid formed of two interleaved and mutually insulated sets of generally parallelly strung elongated linear conductors, the conductors of each set being electrically interconnected, a base positioned adjacent to said grid, a coating on the case surface adjacent to said grid comprising phosphors of three different light producing characteristics forming a color triplet the colors of which are developed upon electron impact and are additive to produce white light, the phosphors being disposed on the base in a repeating pattern of strips generally parallel to the linear conductors of the grid, alternate phosphorcoated strips being wider at the end portions than at the central portions thereof and the intervening phosphor-coated strips being wider at the central portions than at the end portions thereof, the linear conductors of the grid being supported in generally juxtaposed relationship'to the phosphor coatings with the electrodes of the grid electro-optically centered relative to alternate phosphor-coated
  • lll arget structure for cathode-ray tubes adapted for di television images in substantially natural color
  • comprising aggregated and lens-grid formed of two interleaved and mutually insulated sets of generally paral 17 lelly strung elongated linear conductors, the conductors of each set being electrically interconnected, a target surface supported adjacent to said grid, phospor coatings on the target surface adjacent to said grid, the said phosphor coatings being of three different light color pro ducing characteristics collectively forming color triplets which upon electron impact are light-emissive additively to produce White light, the different characteristic phosphors being disposed on the target surface in a repeating pattern of strips generally parallel to the linear conductors With alternate phosphor-coated strips being Wider at the end portions than at the central portions thereof and the intervening phosphor-coated strips being Wider at the central portions than at the end portions thereof, the linear conductors of the grid being supported in generally juxtaposed relationship to the phosphor coatings, and electro-optically

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
  • Video Image Reproduction Devices For Color Tv Systems (AREA)
US399753A 1953-12-22 1953-12-22 Display surface for color television tube Expired - Lifetime US2745033A (en)

Priority Applications (9)

Application Number Priority Date Filing Date Title
BE534344D BE534344A (en(2012)) 1953-12-22
DENDAT1050367D DE1050367B (en(2012)) 1953-12-22
NL193469D NL193469A (en(2012)) 1953-12-22
IT529461D IT529461A (en(2012)) 1953-12-22
CA553317A CA553317A (en) 1953-12-22 Display surface for color television tube
SE526053A SE160882C1 (en(2012)) 1953-12-22 1953-06-06
US399753A US2745033A (en) 1953-12-22 1953-12-22 Display surface for color television tube
GB36999/54A GB777868A (en) 1953-12-22 1954-12-22 Improvements in or relating to display surface for colour television tubes
FR1137763D FR1137763A (fr) 1953-12-22 1954-12-22 Surface de reproduction pour tubes de télévision en couleurs

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US399753A US2745033A (en) 1953-12-22 1953-12-22 Display surface for color television tube

Publications (1)

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US2745033A true US2745033A (en) 1956-05-08

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US399753A Expired - Lifetime US2745033A (en) 1953-12-22 1953-12-22 Display surface for color television tube

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Country Link
US (1) US2745033A (en(2012))
BE (1) BE534344A (en(2012))
CA (1) CA553317A (en(2012))
DE (1) DE1050367B (en(2012))
FR (1) FR1137763A (en(2012))
GB (1) GB777868A (en(2012))
IT (1) IT529461A (en(2012))
NL (1) NL193469A (en(2012))
SE (1) SE160882C1 (en(2012))

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3041489A (en) * 1958-09-26 1962-06-26 Siemens Und Halske Ag Berlin A Single-beam color television picture tube

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1270077B (de) * 1966-11-10 1968-06-12 Werk Fernsehelektronik Veb Verfahren zur Vermeidung von Farbfehlern bei Farbfernsehbildroehren

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2429849A (en) * 1945-09-15 1947-10-28 Rca Corp Color television system
US2619608A (en) * 1950-09-14 1952-11-25 Rca Corp Post-deflected color kinescope
US2669675A (en) * 1952-01-08 1954-02-16 Chromatic Television Lab Inc Display surface for color television tubes

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2429849A (en) * 1945-09-15 1947-10-28 Rca Corp Color television system
US2619608A (en) * 1950-09-14 1952-11-25 Rca Corp Post-deflected color kinescope
US2669675A (en) * 1952-01-08 1954-02-16 Chromatic Television Lab Inc Display surface for color television tubes

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3041489A (en) * 1958-09-26 1962-06-26 Siemens Und Halske Ag Berlin A Single-beam color television picture tube

Also Published As

Publication number Publication date
BE534344A (en(2012))
IT529461A (en(2012))
NL193469A (en(2012))
SE160882C1 (en(2012)) 1957-10-15
DE1050367B (en(2012))
GB777868A (en) 1957-06-26
FR1137763A (fr) 1957-06-04
CA553317A (en) 1958-02-18

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