US3427493A - Direct viewing storage cathode ray tube circuit arrangement - Google Patents

Direct viewing storage cathode ray tube circuit arrangement Download PDF

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Publication number
US3427493A
US3427493A US565950A US3427493DA US3427493A US 3427493 A US3427493 A US 3427493A US 565950 A US565950 A US 565950A US 3427493D A US3427493D A US 3427493DA US 3427493 A US3427493 A US 3427493A
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United States
Prior art keywords
pulses
decay
target
flood
flood beam
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Expired - Lifetime
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US565950A
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English (en)
Inventor
Arthur Mylne Adam
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BAE Systems Electronics Ltd
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Marconi Co Ltd
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Publication date
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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
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S1/00—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith
    • G01S1/02—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith using radio waves
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11C—STATIC STORES
    • G11C11/00—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor
    • G11C11/21—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using electric elements
    • G11C11/23—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using electric elements using electrostatic storage on a common layer, e.g. Forrester-Haeff tubes or William tubes

Definitions

  • a direct viewing storage tube arrangement including a viewing screen, a storage target electrode, a reading electron gun for scanning the target electrode for writing information thereon in the form of stored charges and means for providing a repetitively pulsed flood beam for the production of visible images on the viewing screen. Decay pulses are repetitively applied to the target electrode during alternate pulses of the flood beam and the E. H.T. potential applied to the fluorescent screen in varied between a minimum potential corresponding in time to the applied decay pulses and a maximum potential corresponding in time to the remaining flood beam pulses, corresponding to the production of a visible image.
  • This invention relates to circuit arrangements incorporating direct viewing storage cathode ray tubes and to methods of operating such tubes. More specifically the invention relates to methods of continuously operating direct viewing storage cathode ray tubes (hereinafter termed, for brevity, direct viewing storage tubes) and to circuit arrangements for carrying those methods into effect.
  • the object of the present invention is to provide improved methods of continuously operating direct viewing storage tubes and improved circuit arrangements for carrying out those methods which shall be better suited for the requirements of such equipments as surveillance radars, where good displays, with persistence times of 2 minutes or more, are usually wanted, than are known methods and arrangements.
  • continuous operation of a direct viewing storage tube is meant that form of operation in which information to be displayed-for example information provided by signals derived by a surveillance radaris progressively written in the form of an electrical charge image on the storage target of the tube and this image is continuously decayed or attenuated.
  • the at present usual method of achieving such attention or decay is by simply applying periodically repeated short pulses, hereinafter termed decay pulses to the normally provided backing electrode of said target.
  • decay pulses may be a single train of applied decay pulses or two (or more) trains of pulses of different durations and amplitudes.
  • a train of short duration high amplitude pulses and a train of longer duration lower amplitude pulses may both be applied as decay pulses.
  • continuous operation is in contra-distinction with what is usually called one shot operation in which information is written on the storage target during a scan thereof by the signal modulated writing gun of the tube, the charge image thus obtained being stored indefinitely on the traget and viewable at any time on the fluorescent screen of the tube by switching on the flood gun.
  • a long erasing pulse customarily of about 1 second duration, is applied to the backing electrode of the target.
  • the charge image is attenuated as distinct from being erased. The attenuation being Patented Feb. 11, 1969 effected, in known present day practice, by periodically applying very short pulses to the target backing electrode.
  • the defect termed charge spreading (blurring of the stored image) is apt to occur as a result of the locally increased rate of positive-ion charging, which may reach a value great enough to over-ride the decay action.
  • the persistence time of 3060 seconds is, however, insufficient in many cases e.g. in the case of a surveillance radar, where, as already stated, a radar display with a persistence time of 2 minutes or more is commonly required.
  • the decay pulses tend to degrade the black level of the viewed image, for the screen flashes to full white during each pulse.
  • this defect may not be serious because of the low duty ratio and high repetition rate of the decay pulses usually employed.
  • it does restrict the decay pulses which can be used.
  • the use of a low amplitude high duty-ratio decay pulse train might be preferred, the greater degradation of black produced by such a train as compared with a high amplitude, low duty-ratio decay pulse train may prevent the adoption of the former.
  • the present invention seeks to overcome the foregoing defects and limitations.
  • the flood beam of a direct viewing storage tube having decay pulses applied to its target backing electrode to obtain continuous operation of the tube is pulsed.
  • successively occurring time periods during which the flood beam is effectively pulsed on are employed for the decay phase and for the viewing phase of operation, said phases alternating with one another.
  • apparatus for continuously operating a direct viewing storage tube comprises means for writing information in the form of a charge image on the storage target of the tube, means for applying periodic decay pulses to said target to attenuate the charge images stored thereon and means for translating the said charge images into visible images on the viewing screen of the tube in pulsed fashion by means of a pulsed flood beam which intermittently floods the target and passes therethrough to said screen.
  • the duty-ratio of the pluse flood beam (i.e. the pulse duration for a given pulse repetition frequency) may be adjustable to provide brightness control.
  • the level of decayerase it is possible to reduce the level of decayerase to one corresponding to a persistence time several times as long as that which would be permissible when using the customary known method of continuous operation without causing serious charge spreading or blurring of the charge image.
  • charge spreading as compared to that which occurs when the flood beam is unmodulated, as in normal present day practice, is reduced by a factor of 10.
  • the invention involves a comparative reduction of brightness of the viewed image (approximately in proportion to the duty-rates of the flood beam pulsing), in practice an image bright enough to be viewed in daylight is readily obtainable.
  • the flood gun conditions during on conditions of flood beam pulsing are, of course, those normally specified by the manufacturers for the tube considered.
  • the effective extinction of the Hood beam between pulses can be effected in any of a variety of diflerent ways: for ex ample by reducing, in pulsed fashion, the potential of one or more of the normally provided collimating electrodes of the tube; or, in the case of tubes provided with a space-charge grid in front of the flood gun, by taking this grid to a negative potential; or by taking the normally provided backing electrode of the target to a potential of, say, to volts more negative than the normal value; or (equivalently) by taking the cathode of the flood gun to a potential of, say 5 to 10 volts more positive than the normal value.
  • the flood beam will not be physically cut off but will be diverted to the collector mesh. From the viewpoint of the present invention, however, this may be regarded as the equivalent of cutting off the flood beam.
  • a further improvement is obtained if the E.H.T. applied to the screen of the tube is reduced to a low value or to zero, during a proportion of the flood beam pulses, all decay pulses being confined to periods of low E.H.T.
  • the E.H.T. may be varied so that it is a minimum at the times of alternate flood pulses and a maximum at the times of the remaining flood pulses. If this is done, degradation of the black level of the viewed image by decay pulses can be avoided altogether.
  • the decay pulses may be variable in amplitude and/or in duration.
  • FIGURE 1 is a much simplified schematic representation of one embodiment of the invention and FIGURE 2 is an explantory graphical figure.
  • the tube therein represented is as known per se and comprises with an evacuated envelope 1 a fluorescent screen 2 on the large end wall of the envelope, a storage target or mesh 3, and a collector mesh 4.
  • 5 represents a flood gun system for flooding the storage target with electrons to translate a stored electrical charge image thereon into a corresponding visible image on the screen 2.
  • a writing gun 6 for scanning the target 3 through the mesh 4 and producing stored charge images thereon in well known manner.
  • the tube is provided, on the walls of its enlarged bulb portion, with the customary electrodes 7 for collimating the flood gun electrons.
  • Block 8 represents a source of pulses each of which, when applied, permits the flood beam to flood the target 3 through the collector mesh. Between pulses the flood beam is efiectively cut off. The arrow on block 8 indicates that the pulses are of adjustable duration.
  • Block 9 represents a source of decay pulses which, as indicated by the arrow, may be adjustable in amplitude and/or duration, and which are applied to the target 3. There may be more than one train of applied decay pulses, e.g. a train of short duration high amplitude decay pulses and a train of longer duration lower amplitude decay pulses. Such trains could be obtained from a plurality of pulse generators such as generator 9, operating at different subharmonics of the frequency from generator 8.
  • Block 10 represents a source of periodically varying E.H.T. applied to the viewing screen 2.
  • FIGURE 2 illustrates the operation graphically.
  • pulses in line (a) are two successive pulses from block 8 and represent periods when the flood beam is on.
  • the dotted lines indicate that the pulse widths are adjustable. As will be seen the first of the two pulses of line (a) occurs in a decay phase of operation and the second in a viewing phase.
  • Line (b) of FIGURE 2 shows in full line a decay pulse applied from block 9.
  • the decay pulses can be varied in amplitude, duration or timing (so long as they occur in decay phases) as is indicated by the dotted line pulse shown alongside the full line pulse in line (b) and, as already stated, a plurality of trains of decay pulses of different durations and amplitudes may be applied.
  • Line (0) shows the varying E.H.T. wave applied from block 10 to the screen.
  • the E.H.T. is zero, or approximately so, during the decay phase, and is of approximately normal working value during the viewing phase.
  • the periodicity of flood beam pulsing may be adjustable if desired but if it is the periodicity of the decay pulses should be adjusted therewith to ensure that the decay pulses and flood beam pulses occur in the correct relationship illustrated by FIGURE 2, i.e. the decay pulses must occur within the on period of the flood beam pulses.
  • a direct viewing storage tube arrangement including a tube having a display producing viewing screen, a storage target, means for writing information on the target by the production of a charge image thereon, means for applying periodically recurring decay pulses to said target for attenuating the charge images stored thereon, means for applying a repetitively pulsed flood beam of electrons to said target to produce visible images on said viewing screen, and means for applying to said viewing screen a potential repetitively varying between a maximum potential corresponding in time to the production of images on said viewing screen by the flooding thereof and a minimum potential corresponding in time to the application of decay pulses to said target by said means for applying periodically recurring decay pulses.
  • said means for applying periodically recurring decay pulses to said target comprises means for producing said decay pulses duringalternative applications of said repetitively pulsed flood beam to said target to provide visible image production during the remaining alternative applications of said repetitively pulsed flood beam to said target.
  • said means for applying a repetitively pulsed flood beam comprises means for periodically stopping the production of said flood beam.
  • said means for applying a repetitively varying potential to said viewing screen comprises means for applying said mini mum potential and maximum potential during alternative applications of said pulsed flood beam to said target.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Computer Hardware Design (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
  • Radar Systems Or Details Thereof (AREA)
  • Refuse Collection And Transfer (AREA)
US565950A 1965-08-03 1966-07-18 Direct viewing storage cathode ray tube circuit arrangement Expired - Lifetime US3427493A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB33235/65A GB1129967A (en) 1965-08-03 1965-08-03 Improvements in or relating to direct viewing storage cathode ray tube circuit arrangements

Publications (1)

Publication Number Publication Date
US3427493A true US3427493A (en) 1969-02-11

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US565950A Expired - Lifetime US3427493A (en) 1965-08-03 1966-07-18 Direct viewing storage cathode ray tube circuit arrangement

Country Status (6)

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US (1) US3427493A (xx)
DE (1) DE1564339C3 (xx)
ES (1) ES329830A1 (xx)
GB (1) GB1129967A (xx)
NL (1) NL149036B (xx)
SE (1) SE337630B (xx)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2423901A1 (de) * 1973-05-17 1974-12-19 Tektronix Inc Ladungsbild-speicherroehre
US3925702A (en) * 1974-03-08 1975-12-09 Princeton Electronic Prod Method and apparatus for improving the readout characteristics of electronic storage tubes

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2931938A (en) * 1959-04-09 1960-04-05 Rca Corp Storage tube circuit
US3277333A (en) * 1963-12-13 1966-10-04 Itt Storage tube system and method

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2931938A (en) * 1959-04-09 1960-04-05 Rca Corp Storage tube circuit
US3277333A (en) * 1963-12-13 1966-10-04 Itt Storage tube system and method

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2423901A1 (de) * 1973-05-17 1974-12-19 Tektronix Inc Ladungsbild-speicherroehre
US3925702A (en) * 1974-03-08 1975-12-09 Princeton Electronic Prod Method and apparatus for improving the readout characteristics of electronic storage tubes

Also Published As

Publication number Publication date
DE1564339B2 (de) 1977-09-15
ES329830A1 (es) 1967-09-01
SE337630B (xx) 1971-08-16
NL149036B (nl) 1976-03-15
DE1564339C3 (de) 1978-04-20
NL6610917A (xx) 1967-02-06
DE1564339A1 (de) 1969-09-25
GB1129967A (en) 1968-10-09

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