US2810857A - Electrostatic storage of information - Google Patents

Electrostatic storage of information Download PDF

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Publication number
US2810857A
US2810857A US237000A US23700051A US2810857A US 2810857 A US2810857 A US 2810857A US 237000 A US237000 A US 237000A US 23700051 A US23700051 A US 23700051A US 2810857 A US2810857 A US 2810857A
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United States
Prior art keywords
pulses
oscillations
phase
signal
spot
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Expired - Lifetime
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US237000A
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English (en)
Inventor
Williams Frederic Calland
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National Research Development Corp UK
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Nat Res Dev
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    • 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
    • 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
    • H01J31/58—Tubes for storage of image or information pattern or for conversion of definition of television or like images, i.e. having electrical input and electrical output
    • H01J31/60—Tubes for storage of image or information pattern or for conversion of definition of television or like images, i.e. having electrical input and electrical output having means for deflecting, either selectively or sequentially, an electron ray on to separate surface elements of the screen

Definitions

  • the presentinvention relates to a method of storing digital information of the type in which a Cathode ray beam is caused to explore areas of asurface of an electric charge retaining screen and to liberate secondary electrons from the areas, these secondary electrons being' collected by a collecting electrode, whereby the areas become charged, in which the information to be stored is applied to control the charge produced upon the respecscribed inthe two earlier of these three specifications involves bombarding each of the areas with the cathode ray beam to produce on each area a first state of positive charge representative of one digit and, when required, to represent another digit causing, with the aid of the cathode ray beam, a further, later emission of secondary electrons to the area to decrease the positive charge on the area.
  • later emission of secondary electrons is arranged to take place either from an area outside of and near the area first bombarded or else, in the method known as defocus-focus from an area within that first bombarded.
  • the beam is first directed in a defocused condition upon a relatively large area and is subsequently focused sharply so that it bombards a relatively small area within the first area.
  • the size of the area of the screen made use of in the process of storing each digit is substantially larger than that of the. spot produced by a fccused'beam, even though the stored information is contained in an area United States Patch r11;
  • the present method of recording is an improvement upon this previous method of recording upon a single spot.
  • the present invention has for its object to provide a new or improved method of and means for theelectrostatic storage of digital information in which, as in the method last above referred to, the area required to store each digit may be of minimum size, as abovedefined.
  • a method of storing digital information of the type set forth including the steps of holding the beam stationary or substantially stationary upon each said area during each digit interval (that is to say the time allotted to the storage of each digit) applying two electrical oscillations of high frequency during such interval one to switch the beam on and off at each positive or negative peak of the oscillation and the other to vary the potential dilference between the said areas of the screen surfaceand the collectingelectrode, the two oscillations having at least two different conditions in which the range of said potential difference at the times during which the beam is switched on has'different values respectively, and recording one digit by the use during the said interval of only one of said conditions and recording another digit by the use during the said interval of the same one of the said conditions followed by the other.
  • high frequency is meant a frequency sufficiently high in relation to the frequency at which digits are stored to permit adequate separation of the high frequency. from the frequencies concerned in the digit storage.
  • the different conditions are preferably phasedifierences and for storing binary digits the two conditions of approximately in-phase and approximately anti-phase are preferably used.
  • the invention also provides apparatus forcarrying out the method set forth. i
  • Figure 1 is a block circuit diagram ofone embodiment of the invention and Figure 2 shows waveforms of voltages present at various points on Figure l, the frequency of the oscillations shown in Figure 2(d)' to" (f) being reduced below their usual value for clearness.
  • the spot will have to be stabilised to E0 from a potential E0 -50 volts, that is a positive charge equivalent to 50 volts will have to be produced on the spot and the production of this charge will give rise to a signal in the signal plate which may be fed through a filter to the amplifier and utilised in the normal way to indicate that the spot under examination had previously been subjected to bombar' ment under the control of both A and B pulses.
  • this shows a cathode ray tube 10 provided with a regenerative loop connecting hte signal or pick-up plate 11 and control grid 12, the loop including an amplifier 13 and a reading and writing unit 14 which may have the form shown in Figure 3 of the specification of co-pending U. S. application Ser. No. 93,612 filed May 16, 1949, now Patent No. 2,777,971.
  • the dot, strobe and dash pulses are applied to the read and write unit 14 as described in the last-mentioned specification.
  • the idealised wave form of the dot and dash pulses is shown in Figure 2 at (a) and (b) respectively, the former having a duration t, and the latter a duration t,.
  • the duration t is what is previously referred to as the digit interval.
  • the reading and writing unit 14 is as follows: The unit normally transmits to its output dot pulses from dot generater 16. If a positivegoing signal is generated on the pickup plate 11, this signal is amplified at amplifier 13 and fed to the unit 14, where a desired part is selected by a strobe pulse from strobe generator 17, this desired part serving to pass to the'output of the unit 14a dash pulse from the generator '18.
  • a dash pulse is 4 fed to the unit 14 through a write terminal 28.
  • the pick-up plate 11 has applied to it from an R. F. oscillator 1.9 a continuous ZO-megacycle oscillation, filters 20 and 21 being provided to isolate the amplifier 13 from R. F. oscillations and to prevent read signals reaching the R. F. oscillator respectively.
  • a modulator 22 is connected to the output of the unit 14 and is thus inserted between the unit 14 and the control grid 12; a ZO-megacycle signal from the oscillator 19 is fed to the modulator 22 by two paths one including a gate device 23 and the other a phase-reversing circuit 24 and another gate device 25.
  • the oscillator 19 together with the phase inverter 24 constitute oscillation generating means generating at two output terminals thereof respectively, namely at the outputs connected to the inputs of the gates 23 and 25, two high-frequency oscillations having the same frequency and different phase.
  • Dot pulses are fed to the gating device 25 to open this gate for the duration z of each dot pulse and dash minus dot pulses, having the form shown in Figure 2(c), and derived in a generator 26 by the subtraction of dot pulses from dash pulses, are fed to the gating device 23 to open this gate for the duration z,,-t of the pulses 27.
  • the modulator 22 acts as a form of gate to pass R. F. oscillations from 23 or 25 only while positive pulses are applied thereto from the unit 14.
  • the cathode ray beam is deflected to scan a raster on the screen of the tube 10 by saw-tooth oscillations generated by X-scan and Y-scan generators 29 and 30 respectively, controlled by the pulses from 15, these oscillations being applied for example to coils 31 and 32 respectively.
  • the X-scan generator is arranged to generate a stepped wave form so that the beam remains stationary at least throughout each digit interval (t2).
  • the collector of secondary electrons is a conducting wall coating 33 which is earthed, so that E0 is approximately earth potential, and the cathode 34 is maintained at a suitable negative potential with respect to earth.
  • the modulator is rendered operative for the whole of a dash interval 12 to pass oscillations from gates 23 or 25.
  • the gate 25 is open for the first part ii of this interval and passes A pulses to the grid 12
  • the gate 23 is open for the last part t2-t1 of the period and passes B pulses to the grid 12.
  • the first part of the bombardment is with antiphase pulses at 11 and 12 and the last part is with inphase pulses at 11 and 12.
  • the filter 20 may be found suffici'ent or the response of the amplifier 1 3 may be arranged to achieve the desired result.
  • the effect of the electron cloud pulses can be made much smaller than in previous devices of the type referred to because of the greater magnitude which can be given to the signal representative of the dash condition; This can be explained as follows:
  • the positive signal derived on reading a dash is derived from the creation on a dot area of a positive charge of potential amounting to only a few volts.
  • the potential which is produced when reading is determined primarily by the peak to peak amplitude of the R. F. voltage which is applied to the pick-up plate, and the read signal may, within reason, be made as large as is desired.
  • the conventional dot and dash time intervals may-be replaced by two dot intervals, information of one sort being written by the illumination only during the first dot interval which corresponds also to the reading interval, information of the second sort being recorded by illumination during the first (reading) dot interval followed by illumination during the following (modifying) dot interval.
  • the polarity of the read signal developed may be arranged to be negative. If a negative read signal is employed, the effect of negative cloud pulses may be eliminated by integration as described in U. S. application Serial No. 193,772 filed November 3, 1950, now patent 2,749,439.
  • phase of the R. F. oscillations applied to switch the beam may be maintained constant and the phase 'of the R. F. oscillations applied to the pick-up plate or collector electrode may be varied between the in-phase and anti-phase condition.
  • Gate circuits such as 23 and '25 may be provided for this purpose.
  • the R. F. oscillations applied to the pick-up plate and control grid (or cathode) differ in frequency by an amount equal to the digit repetition rate.
  • the beat effect between the two frequencies can be caused to give approximately in-phase bombardment for illumination during the periods a and approximately antiphase bombardment during the periods t2ti.
  • a third state of charge may, for example, be obtained by providing a circuit for generating an oscillation in phase quadrature and employing with this circuit a further gate circuit such as 23 and 25.
  • means may be provided for applying to the pick-up plate oscillations from the oscillator 19 modulated to any desired number of fixed amplitudes, the desired one of these fixed amplitudes being selected according to the nature of the information to be stored.
  • a number of different conditions greater than two may of course be obtained by providing means for varying the phase of the oscillations applied to the pick-up plate and the grid or cathode of the tube or for modulating the amplitude of the oscillations applied to the pick-up plate and also providing means to vary the phase of the oscillations applied to the grid or cathode of the tube.
  • a method of storing digital information employing a cathode ray tube having an electric charge-retaining recording surface positioned to be explored by the cathode ray beam and a collecting electrode positioned to collect secondary electrons from said surface, the method comprising directing the beam successively towards spaced areas of said surface and maintaining the beam substantially stationary in such directions, recording one digit by applying a first burst of high frequency oscillation to switch 'said beam on and ofl?
  • Apparatus for storing digital information comprising a cathode ray tube, an electric charge-retaining recording surface in said tube, beam-intensity control means for said tube, beam deflecting means to direct the cathode ray beam successively on spaced areas of said surface, a signal pick-up electrode capacitively coupled to said surface, a collecting electrode positioned to collect secondary electrons from said surface, oscillation generating means generating a first and a second high frequency oscillation, said first and second oscillations having the same frequency and different phase, coupling means between said oscillation generating means and one of said electrodes applying said first oscillation to vary the potential difference between said electrodes, and coupling means between said oscillation generating means and said beam-intensity control means applying said second oscillation to vary the intensity of said beam.
  • Apparatus according to claim 4 comprising a pulse generator generating beam intensity controlling pulses to vary a bias .upon said beam-intensity control electrode between conditions in which said high frequency oscillations applied to said control electrode do and do not switch said beam on and off, a selective control device to permit and prevent application of pulses from said pulse generator to said beam-intensity control electrode and means rendering said selective control device operative and inoperative in response to information to be stored.
  • Apparatus according to claim 6, comprising coupling means between said signal pick-up electrode and said selective control device to apply voltage from said pick-up electrode to control the application of pulses from said pulse generator to said beam intensity control electrode and thereby to regenerate electrostatic charges on said surface.
  • Apparatus for storing digital information comprising a cathode ray tube, an electric charge-retaining recording surface in said tube, a beam-intensity control electrode for said tube forming part of a first control system, beam deflecting means to direct the cathode ray beam successively on spaced areas of said surface, a second control system comprising a signal pick-up electrode capacitively coupled to said surface and a collecting electrode positioned to collect secondary electrons from said surface, oscillation generating means having two output terminals and generating at said terminals respectively two high frequency oscillations of a predetermined frequency and of difierent phases, switching means connecting two input terminals in succession to an output terminal thereof, couplings between the two outputs of said generating means and said two input terminals respectively, a coupling between said output terminal of said switching means and an electrode of one of said control systems, and a coupling between one of the terminals of said generating means and an electrode of the other of said control systems.
  • said switching means connect a first of said input terminals to the output terminal of said switching means during a first recurrent time interval and connect the second of said input terminals to the output terminal of said switching means during a second recurrent time interval following said first time interval
  • said apparatus comprising a pulse generator generating pulses extending over at least part of said second time interval, and means coupling said pulse generator to said beam-intensity control electrode, said coupling means including selective switch means responsive to signals to be stored to control the application of said pulses to said beam-intensity control electrode and thereby to render said beam operative on peaks of said high frequency oscillations during at least part of said second time interval only in response to a signal of a predetermined character.
  • Apparatus according to claim 10 comprising coupling means between said signal pick-up electrode and said selective switch means to apply voltages from said pick-up electrode to said selective switch means, whereby electrostatic charges on said surface are regenerated.

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  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)
  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
  • Optical Recording Or Reproduction (AREA)
US237000A 1950-07-20 1951-07-16 Electrostatic storage of information Expired - Lifetime US2810857A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB18204/50A GB705502A (en) 1950-07-20 1950-07-20 Improvements in and relating to the electrostatic storage of information

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US2810857A true US2810857A (en) 1957-10-22

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US (1) US2810857A (d)
BE (1) BE504758A (d)
CH (1) CH298555A (d)
DE (1) DE923094C (d)
FR (1) FR1048349A (d)
GB (1) GB705502A (d)
NL (1) NL90305C (d)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2863090A (en) * 1953-05-26 1958-12-02 Ibm R. f. modulation system for barrier grid storage tubes
US3619704A (en) * 1969-07-09 1971-11-09 James W Schwartz Signal storage tube system with enhanced signal-to-noise ratio

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1060907B (de) * 1950-02-21 1959-07-09 Charles Ferencz Pulvari Schaltungsanordnung zum Registrieren und/oder Reproduzieren von binaeren Informationen
DE1183942B (de) * 1955-08-06 1964-12-23 Telefunken Patent Verfahren zur Vereinfachung des Verarbeitens eines aus einem Speicher durch Abtastung entnommenen elektrischen Signals
DE1272370B (de) * 1964-01-13 1968-07-11 Tektronix Inc Speicherverfahren fuer eine mit bistabiler Ladungsbildspeicherung arbeitende Kathodenstrahlroehre

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2130134A (en) * 1937-01-30 1938-09-13 Rca Corp Oscillograph apparatus
US2241809A (en) * 1937-07-13 1941-05-13 Ruth C Gilman Television radial scanning system employing cathode beam
US2290581A (en) * 1939-02-17 1942-07-21 Rca Corp Light valve
US2465364A (en) * 1945-09-14 1949-03-29 Standard Telephones Cables Ltd Oscillograph system
US2472165A (en) * 1947-04-29 1949-06-07 Philco Corp Automatic focus control for cathode-ray tubes
US2474628A (en) * 1948-05-20 1949-06-28 Hurvitz Hyman Indicator
US2523328A (en) * 1948-06-30 1950-09-26 Gen Electric Cathode-ray mapping system
US2552022A (en) * 1945-06-08 1951-05-08 Nat Res Dev Expanded sweep and calibrated marker for cathode-ray tube trace
US2576040A (en) * 1948-03-10 1951-11-20 Bell Telephone Labor Inc Cathode-ray device
US2589460A (en) * 1948-06-18 1952-03-18 Melpar Inc Electronic commutator
US2617963A (en) * 1949-05-26 1952-11-11 Int Standard Electric Corp Storage tube system
US2639425A (en) * 1943-12-16 1953-05-19 James L Russell Cathode-ray tube timing pulse generator for radar systems and the like

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2130134A (en) * 1937-01-30 1938-09-13 Rca Corp Oscillograph apparatus
US2241809A (en) * 1937-07-13 1941-05-13 Ruth C Gilman Television radial scanning system employing cathode beam
US2290581A (en) * 1939-02-17 1942-07-21 Rca Corp Light valve
US2639425A (en) * 1943-12-16 1953-05-19 James L Russell Cathode-ray tube timing pulse generator for radar systems and the like
US2552022A (en) * 1945-06-08 1951-05-08 Nat Res Dev Expanded sweep and calibrated marker for cathode-ray tube trace
US2465364A (en) * 1945-09-14 1949-03-29 Standard Telephones Cables Ltd Oscillograph system
US2472165A (en) * 1947-04-29 1949-06-07 Philco Corp Automatic focus control for cathode-ray tubes
US2576040A (en) * 1948-03-10 1951-11-20 Bell Telephone Labor Inc Cathode-ray device
US2474628A (en) * 1948-05-20 1949-06-28 Hurvitz Hyman Indicator
US2589460A (en) * 1948-06-18 1952-03-18 Melpar Inc Electronic commutator
US2523328A (en) * 1948-06-30 1950-09-26 Gen Electric Cathode-ray mapping system
US2617963A (en) * 1949-05-26 1952-11-11 Int Standard Electric Corp Storage tube system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2863090A (en) * 1953-05-26 1958-12-02 Ibm R. f. modulation system for barrier grid storage tubes
US3619704A (en) * 1969-07-09 1971-11-09 James W Schwartz Signal storage tube system with enhanced signal-to-noise ratio

Also Published As

Publication number Publication date
CH298555A (de) 1954-05-15
DE923094C (de) 1955-02-03
GB705502A (en) 1954-03-17
NL90305C (d)
BE504758A (d)
FR1048349A (fr) 1953-12-21

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