US3165665A - Direct viewing storage tube arrangements producing "black and white" pictures - Google Patents

Direct viewing storage tube arrangements producing "black and white" pictures Download PDF

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Publication number
US3165665A
US3165665A US166303A US16630362A US3165665A US 3165665 A US3165665 A US 3165665A US 166303 A US166303 A US 166303A US 16630362 A US16630362 A US 16630362A US 3165665 A US3165665 A US 3165665A
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United States
Prior art keywords
mesh
insulator
flood
potential
storage
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Expired - Lifetime
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US166303A
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English (en)
Inventor
Firmin Jervois Campbell
Sinclair Ian Robertson
Davies Norman John
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Teledyne UK Ltd
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English Electric Valve Co Ltd
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Publication date
Application filed by English Electric Valve Co Ltd filed Critical English Electric Valve Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J31/00—Cathode ray tubes; Electron beam tubes
    • H01J31/08—Cathode ray tubes; Electron beam tubes having a screen on or from which an image or pattern is formed, picked up, converted, or stored
    • H01J31/10—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes
    • H01J31/12—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes with luminescent screen
    • H01J31/18—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes with luminescent screen with image written by a ray or beam on a grid-like charge-accumulating screen, and with a ray or beam passing through and influenced by this screen before striking the luminescent screen, e.g. direct-view storage tube

Definitions

  • This invention relates to storage tube circuit arrangements and more specifically to arrangements including storage tubes of the kind comprising an electric charge storage structure having a backing grid or mesh with an insulator on one side thereof, a so-called writing gun adapted to scan said structure with a signal-modulated electron beam to produce on said insulator stored electric charges controlled by said signals, a so-called flood gun adapted to cover the working area of said structure with a collimated substantially uniform density flood beam of electrons, and a fluorescent viewing screen positioned to receive electrons of the flood beam which pass through said structure.
  • the stored charge pattern on the storage structure determines whether or not flood beam electrons will pass through it at any particular point to reach the viewing screen on which, accordingly, appears a visible picture determined by the signals.
  • tubes of this kind will hereinafter be referred to as direct viewing storage tubes.
  • This result may be achieved by a circuit arrangement which will cause the tube to operate in a bistable manner so that signals above a predetermined strength applied to modulate the writing beam will result in stored charges which will cause flood beam electrons to pass through the storage grid or mesh at full strength at the points where such charges are stored while signals below said predetermined strength will cause the appropriate points on said structure substantially to cut off the flood beam electrons.
  • the present invention seeks to provide improved, simple and reliable circuit arrangements which will produce such bi-stable operation.
  • a storage tube circuit arrangement comprises a direct viewing storage tube of the determined potential such as to permit the passage of flood beam electrons therethrough.
  • the flood gun cathode potential is held constant and said recurrent potentials applied to the backing grid or mesh.
  • these potentials are applied as successively different valued pulses, the amplitudes of which are so chosen in relationto the secondary emission ratio-voltage characteristic curve of the storage mesh that, in the absence of stored charges, the storage mesh is stabilized at a predetermined potential sufficient to prevent the passage of flood beam electrons and, in the presence of stored charges, the storage mesh is stabilized at a potential tha permits the passage of flood beam electrons.
  • said two different potentials occur for equal time periods and are so chosen that in the absence of stored charges the larger of said potentials alone produces a secondary emission ratio, in relation to flood beam electrons, which is approximately as much above unity as the corresponding secondary emission ratio produced by the smaller of said two potentials alone is below unity.
  • the aforesaid potentials are applied in the form of two time-spaced approximately rectangular pulses. This, although preferred, is not a necessity and other waveforms inwhich the required two potentials successively occur may be used. For example there may be a single pulse having two different successive potential values such as would be obtained by reducing to zero the time spacing between the aforesaid two approximately rectangular pulses.
  • the repetition frequency should be high enough not to result in visible flicker of the produced pictures and the duration of and time interval between the successively occurring potential values should be so chosen as to result in a duty ratio (ratio of duration of the said potential values to the repetition period) such as will result in pictures of the required brightness and good light-dark contrast.
  • a duty ratio ratio of duration of the said potential values to the repetition period
  • FIGURE 1 is a schematic simplified view of one embodiwriting gun audaflood gun on one side of said mesh
  • means for modulating the writing electron beam of said tube by means of input signals and means for applying between the backing grid or mesh, which has an insulator on one side thereof, and the flood gun cathode of said tube different successively recurrent potentials so chosen in relation to the secondary emission rangement comprises a cathode FC and electrodes FGl,
  • the writing gun arrangement comprises a cathode WC, control electrodes or so-called grids WGl, WGZ and WG3 (the last being for focussing) and mutually perpendicular deflecting pairs of plates D for causing the writing beam spot to scan over the stor age mesh in a predetermined manner;
  • the flood gun ar- FGZ and F63, F83 being constituted by wall deposit and FG2 being in part constituted by wall deposit.
  • a second ary electron collector mesh CM arranged to collect secondary electrons from the storage mesh SM is positioned on the gun side of the storage mesh adjacent thereto.
  • both said potenr Signals to be displayed are applied from a signal source SS to the writing gun control electrode WGl to modulate the scanning Writing beam in intensity and a recurrent waveform consisting of two approximately rectangular pulses of different amplitudes and equal durations are applied from a source PS together with a D.C. potential, whose value is best found by trial and error, to the backing electrode (not separately shown) of the storage mesh SM.
  • the upper part of FIGURE 2 is a desired characteristic curve connecting secondary emission ratio R (ratio of emitted secondary electrons to incident primary electrons) as ordinates, with voltage V of the insulating surface of the storage mesh referred to the flood gun cathode potential as abscissae, of a direct viewing storage tube such as is shown in FIGURE 1.
  • the horizontal line X represents unity secondary emission ratio.
  • the lower part of FIG- URE 2 is represented, in conventional manner, the effects of pulses applied from the source PS.
  • the vertical axis is time, T and against it, horizontally, are plotted values of voltage V at the insulating surface of the storage mesh SM referred to the potential of the flood gun cathode, assuming the flood gun to be in operation. Assume for the moment that no charges have been written on the mesh. Then if a succession of small voltage pulses of suitable amplitude like that of the pulse P1 is alone applied to the storage mesh backing electrode, the insulating surface thereof will receive electrons from the flood beam during the occurrence of the pulses and will set itself to a negative voltage, approximately equal to the amplitude of the pulses, of, say 4 volts, such voltage being more negative than that corresponding to black (i.e. fully dark) on the viewing screen. Under these conditions no flood gun electrons will pass through the mesh to the viewing screen in the intervals between the pulses. This is the initial tube-setting operation.
  • the amplitude of pulse P2 is such as to produce a secondary emission ratio R just above unity (i.e. the amplitude is such that the insulator potential just exceeds the so-called first crossover potential at which the secondary emission characteristic curve of FIGURE 2 crosses the line X), with the result that during the occurrence of pulse P2 the landing of flood beam electrons on the storage insulator causes its potential to increase positively.
  • the succeeding pulse P1 will now drive the storage insulator positive by a small amount such as to produce a secondary emission ratio R which is less below unity than the comparable value of R during pulse P2 was above it.
  • the potential of the storage insulator drifts negatively during the occurrence of pulse P1 but by an amount which is less than the positive drift during the occurrence of pulse P2.
  • the secondary emission characteristic of the insulator surface has a slope, at a potential of V, which is of opposite sense to, and greater in Value than, that at the first crossover potential, a point is reached at which the positive drift during pulse P2 is compensated by the negative drift during pulse P1 (i.e.
  • pulse P2 produces a secondary emission ratio R which is as much above unity as that due to pulse P1 is below it), and the insulator surface adopts a substantially stabilized potential, between pulses, corresponding to black on the Viewing screen.
  • R secondary emission ratio
  • the peak of pulse P2 will correspond to a value of secondary emission ratio R which is in excess of unity by an amount greater than that by which the value of R corresponding to the peak of pulse P1 is below unity. Consequently, the written areas will increase positively in potential until they are stabilised at zero potential.
  • the pulses P1 and P2 need not be of equal duration, in which case the amplitudes of the pulses need not be such as to correspond, when the insulator surface of the storage electrode carries no written charge, to values of secondary emission ratio R which are equally and oppositely disposed about unity but will have values such that, in these conditions, the amount of positive charge acquired by the insulator during the larger pulse equals that lost during the shorter pulse.
  • the amplitudes of the pulses must also be such that when the insulator is at flood-gun cathode potential the amount of positive charge acquired during the larger pulse exceeds that lost during the smaller pulse.
  • the different potentials applied to the backing grid or mesh may be in the form of a single pulse such as would be obtained if the time-spacing between the aforesaid two pulses, whether of equal duration or not, were reduced to zero.
  • Stored signal patterns written on the mesh can obviously be expunged when desired by omitting the larger amplitude pulses in the recurrent double pulse waveform. If desired, means may be provided for adjusting the amplitude of one or both of the pulses included in the waveform.
  • a storage tube circuit arrangement including a direct viewing storage tube comprising an electric charge storage structure having a backing grid or mesh with an insulator on one side thereof, a writing gun adapted to scan said structure with a signal-modulated electron beam to produce on said insulator stored electric charges controlled by said signals, a flood gun adapted to cover the working area of said structure with a collimated substantially uniform density flood beam of electrons, and a fluorescent viewing screen positioned to receive electrons of the flood beam which pass through said structure, means for modulating the writing electron beam of said tube by means of input signals, and means for applying between the backing grid or mesh and the cathode of said flood gun successively diflerent recurrent potential values so chosen in relation to the secondary emission ratio-voltage characteristic curve of said insulator that, in the absence of stored charges produced by said signals, said insulator is stabilized at a predetermined potential suflicient to prevent the passage of flood beam electrons therethrough and, in the presence of stored charges produced by said signals, said insulator is stabilized at a second

Landscapes

  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
  • Manufacture Of Electron Tubes, Discharge Lamp Vessels, Lead-In Wires, And The Like (AREA)
US166303A 1961-01-13 1962-01-15 Direct viewing storage tube arrangements producing "black and white" pictures Expired - Lifetime US3165665A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1522/61A GB944112A (en) 1961-01-13 1961-01-13 Improvements in or relating to storage tube circuit arrangements

Publications (1)

Publication Number Publication Date
US3165665A true US3165665A (en) 1965-01-12

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US166303A Expired - Lifetime US3165665A (en) 1961-01-13 1962-01-15 Direct viewing storage tube arrangements producing "black and white" pictures

Country Status (5)

Country Link
US (1) US3165665A (nl)
CH (1) CH391902A (nl)
DE (1) DE1464544B2 (nl)
GB (1) GB944112A (nl)
NL (2) NL142015B (nl)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3325673A (en) * 1962-08-06 1967-06-13 Tektronix Inc Charge integrating bistable storage tube
US3753129A (en) * 1972-01-24 1973-08-14 Tektronix Inc Stabilization of prepare voltage of transmission storage target

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2843799A (en) * 1953-08-14 1958-07-15 Rca Corp Direct-view electrical storage tube and methods of operating same

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2843799A (en) * 1953-08-14 1958-07-15 Rca Corp Direct-view electrical storage tube and methods of operating same

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3325673A (en) * 1962-08-06 1967-06-13 Tektronix Inc Charge integrating bistable storage tube
US3753129A (en) * 1972-01-24 1973-08-14 Tektronix Inc Stabilization of prepare voltage of transmission storage target

Also Published As

Publication number Publication date
CH391902A (fr) 1965-05-15
GB944112A (en) 1963-12-11
NL273499A (nl)
DE1464544A1 (de) 1969-04-10
DE1464544B2 (de) 1971-01-21
NL142015B (nl) 1974-04-16

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