US3413513A - Method and apparatus for increasing writing rate of storage tube - Google Patents

Method and apparatus for increasing writing rate of storage tube Download PDF

Info

Publication number
US3413513A
US3413513A US659826A US65982667A US3413513A US 3413513 A US3413513 A US 3413513A US 659826 A US659826 A US 659826A US 65982667 A US65982667 A US 65982667A US 3413513 A US3413513 A US 3413513A
Authority
US
United States
Prior art keywords
voltage
storage
target
charge image
flood
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US659826A
Other languages
English (en)
Inventor
James J Donoghue
Jr Richard B Mcmillan
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Tektronix Inc
Original Assignee
Tektronix Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tektronix Inc filed Critical Tektronix Inc
Priority to US659826A priority Critical patent/US3413513A/en
Application granted granted Critical
Publication of US3413513A publication Critical patent/US3413513A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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
    • H01J31/122—Direct viewing storage tubes without storage grid
    • 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

  • HOR 22 swEEi, RASTER p54 GEN. S
  • ABSTRACT OF THE DISCLOSURE A bistable storage tube and a method of operating the same to increase its writing rate.
  • An enhancement pulse is applied to the flood gun cathode which is much greater than the first crossover voltage to enable storage of written charge images of initially low voltage.
  • the pulse is terminated at such time as to prevent the potential of the unwritten background areas of the storage dielectric from increasing above the first crossover voltage. This is possible because the more positive voltage portions of the storage dielectric charge at a faster rate than the more negative unwritten background target areas.
  • the subject matter of the present invention relates generally to electron image storage apparatus, and in particular to methods and apparatus for operating a bistable storage tube to increase its Writing rate so that the electron beam within such tube may be moved across its storage target at a faster rate and still produce a charge image which is stored an indefinite controlable time.
  • one embodiment of the method of operation of the present invention involves turning off the flood electron guns within such tube to prevent low velocity flood electrons produced by such flood gun from striking the storage target during the time such target is bombarded by a beam of high velocity writing electrons to produce the charge image on such target. Then the target is bombarded with flood electrons of increased velocity immediately after the charge image is formed by the writing electrons after which the velocity of such flood electrons is decreased below that which will drive the potential of the background areas of the storage target above the first cross over voltage of the secondary emission characteristic of such target at which the secondary emission ratio is one.
  • the first cross over voltage is the minimum voltage difference between the bombarded rear surface of the storage dielectric of the target and the flood gun cathode which is necessary to enable bistable storage.
  • the present method of operating the storage target to increase its writing rate is especially useful when employed for a cathode ray oscilloscope having a direct viewing bistable storage tube as its signal display device.
  • This enables high frequency input signals or those having extremely fast rise times to be stored on the target of the storage tube of such oscilloscope even though such signals are above the normal writing rate of such target achieved by conventional operation.
  • the method of the present invention may be employed for storing both repetitive signals and transient signals. However high frequency repetitive signals may be stored by charge image inte- 3,413,513 Patented Nov.
  • the method of operation of the present invention has several advantages over conventional methods of operating storage tubes including increasing the frequency response of the storage tube by effectively increasing th writing rate of the storage target of such tube in a simple and efficient :manner.
  • the present method may be applied to all conventional storage tubes including direct readout tubes employing a grid control or transmission type storage target and a separate phosphor screen spaced from such target, as Well as nonconventional tubes employing phosphor storage targets such as are described in copending US. patent applications Ser. No. 180,457, filed Mar. 19, 1962, by Robert H. Anderson, and entitled, Electron Discharge Display Device, now Patent No. 3,293,473, and Ser. No. 299,422, filed Aug. 1, 1963, by Charles B. Gibson, entitled, Storage Target for Cathode Ray Tube and Photographic Method of Manufacture, now Patent No. 3,293,474.
  • Apparatus for carrying out the method of operation of the present invention is simple and inexpensive.
  • one embodiment of this apparatus is in the form of a manual switch having a movable contact connected to the cathodes of the flood guns within the storage tube with one of its fixed contacts connected to a source of positive D.C. voltage source above cut off and another of its fixed contacts connected to the common terminal of a capacitor and a charging resistance which are connected in series between a negative DC. voltage source and ground.
  • the apparatus may be of a type to provide automatic operation, in which case it may include a blanking signal generator which is triggered by the input signal applied to the vertical deflection plates of the storage tube, and applies a negative voltage blanking pulse to the control grids of the flood guns to cut off such flood guns so that a capacitor connected to the cathode of each flood gun charges to a suitable negative DC voltage to increase the velocity of the flood electrons when such flood gun is turned back on by termination of the blanking pulse.
  • This automatic or triggered operation has the advantage that it enables the writing rate enhancement pulse to be applied immediately after the input signal has written its charge image on the storage target before the potential of such charge image decreases appreciably due to leakage. Therefore, such triggered operation is very desirable when storing high speed transient signals whose charge images are initially of very low potential.
  • target areas of different initial voltage potential charge at different rates when low velocity flood electrons bombard such target areas have also been discovered that target areas of different initial voltage potential charge at different rates when low velocity flood electrons bombard such target areas.
  • a target area of higher potential charges at a faster rate than a target area of lower potential so that the potential difference between such target areas increases with time during charging.
  • the waveform charge image produced on the storage target is of only a slightly greater potential than the background areas of the storage targets, it is still possible to store such charge image bistably by increasing the potential of the charge image and the background areas by applying a negative enhancement pulse to the flood gun cathode until the potential of the charge image is greater than the first cross over voltage but terminating the enhancement pulse before the potential of the background areas exceed the first cross over voltage.
  • this increased potential difference between written target areas and unwritten target areas due to their different charging rates may be further increased by employing a spike enhancement pulse having an amplitude greater than the first cross over voltage and exponential trailing edge which can be produced by discharging a suitable capacitor through resistance of the proper value.
  • Another object of the present invention is to provide an improved method and apparatus for operating a bistable storage tube which allows such tube to store higher speed transient signals as well as repetitive signals of greater frequency.
  • a further object of the invention is to provide a simple method of increasing the writing rate of a bistable storage tube by preventing low velocity holding electrons from striking the storage target during the time the charge image is produced on such target by high velocity writing electrons and momentarily increasing the velocity of the holding electrons striking the storage target immediately after the charge image is produced.
  • An additional object of the present invention is to provide a simple and inexpensive electrical circuit which may be operated by a manual switch for increasing the writing rate of any bistable storage tube.
  • a still further object of the present invention is to provide an electrical circuit for increasing the writing rate of a bistable storage tube automatically by triggering such circuit in response to the input signal to be stored.
  • FIG. 1 is a schematic diagram of one embodiment of the apparatus made in accordance with the present invention.
  • FIG. 2 is a curve of the voltage applied to the cathode of the flood guns employed in the storage tube of FIG. 1;
  • FIG. 3 is a schematic diagram of another embodiment of a circuit for operating the flood guns in the storage tube of FIG. 1 by automatic triggering;
  • FIG. 4 shows the voltage Waveforms applied to the cathode and control grid of the flood gun of FIG. 3;
  • FIGS. 5A, 5B and 5C are diagrams of the waveforms of different types of writing speed enhancement voltage pulses which may be applied to the flood gun cathodes of FIG. 1 and the potentials of written and background target areas effected by such enhancement pulses.
  • FIG. 1 One embodiment of the charge image storage apparatus of the present invention is shown in FIG. 1, and includes a conventional bistable storage tube 10 or a direct viewing bistable storage tube similar to that described in the copending U.S. patent application Ser. No. 180,457, referred to above, so that such tube will not be discussed in detail.
  • the electrical input signals to be displayed are applied across a pair of vertical deflection plates 12 at least one of which is connected to an input terminal 14 through a vertical amplifier 16 and a two position selector switch 18.
  • the movable contact of the selector switch 18 is moved to the WRITE position shown, to apply the input signal to the vertical deflection plates during the writing operation of the storage tube.
  • a pair of horizontal deflection plates 20 are also provided within the storage tube and are connected to a horizontal sweep generator 22 through a second selector switch 24 whose movable contact is ganged to that of switch 18.
  • the horizontal sweep generator 22 applies a conventional saw tooth or ramp shaped sweep signal across the horizontal deflection plates 20 when the selector switch 24 is in the WRITE position shown.
  • a storage target 26 at one end of the tube 10 is bombarded by a narrow beam of high velocity writing electrons which are emitted from a cathode 28 at the other end of such tube.
  • the writing beam is deflected by the signals on the horizontal and vertical deflection plates so that it produces a charge image on the storage dielectric of such target which corresponds to the waveform of the vertical input signal applied to input terminal 14.
  • the potential of the charge image produced on the storage target 26 will be sufficient to enable bistable storage of such charge image for an indefinite controlable time.
  • This bistable storage is caused in a conventional manner by bombarding such storage target substantially uniformly with low velocity flood electrons emitted by a pair of flood guns 30.
  • the holding or flood electrons drive the potential of the charge image up to a stable voltage near the voltage of the collector electrode of such storage target.
  • the unwritten background areas of the storage target whose potential is below the first cross over voltage are driven downward to a stable voltage adjacent the voltage of the cathodes 31 of the flood guns. In this manner, all areas of the rear surface of the storage target are held at one of these two stable voltages. It has been discovered that the effective first cross over voltage varies with the field produced across the storage dielectric, at least for the phosphor target referred to below, so that this term will be used to indicate the minimum charge voltage necessary for storage and may vary in value with the voltage applied to the target electrode.
  • the storage target 26 may be similar to the direct viewing target disclosed in copending U.S. patent application Ser. No. 180,457, referred to above, or the split screen target shown in copending U.S. patent application Ser. No. 214,877, filed on Aug. 6, 1962, by Robert H. Anderson, entitled Storage Tube, now Patent No. 3,214,631.
  • the storage dielectric is a thin layer of phosphor material which serves the dual functions of storing the charge image bistably and of converting the charge image into a light image for direct viewing. This phosphor storage dielectric is supported over a light transparent electrical conductive film of tin oxide coated on the rear surface of the face plate of the tube envelope.
  • This conductive film serves as the collector electrode for the secondary electrons emitted by the phosphor layer due to the porous structure of such layer and is connected to a target voltage produced across a fixed load resistor 32.
  • the load resistor 32 is connected in series with a variable resistor 33 be- I tween a source of positive D.C. supply voltage of about age above which the storage target is driven to a uniformly positive or completely Written condition by the flood electrons.
  • the low velocity holding or flood electrons emitted from the cathodes 31 are normally transmitted through control grid 34 and anode 36 of the flood guns onto the surface of the storage target 26 after passing through at least one wall band electrode 38 of silver or other conductive material coated on the inner surface of the funnel portion of the envelope.
  • the wall band electrode 38 is connected to a positive DC bias voltage of about +50 volts when the flood gun cathode 31 is normally grounded, in order to spread the flood electrons substantially uniformly over the surface of the storage target and to collimate such flood electrons so that they strike the target at substantially right angles thereto. It should be understood that while the Wall band electrode 38 is shown as a single electrode it may be provided as a plurality of spaced wall bands of varying potential for more precise control of the flood electrons.
  • this flood gun type storage tube may be replaced by one in which the holding electrons are provided in the form of a narrow beam similar to that of the writing beam but of lower velocity, which is deflected over the surface of the storage target in a TV raster pattern to enable storage of the charge image in a similar manner to the flood electrons.
  • the input signal is a repetitive signal it is possible to increase the potential of the charge image even more by maintaining the flood guns turned off during several successive cycles of the input signal so that charge image of these successive input signals are superimposed on the storage target and their potentials effectively added together to increase the total potential of the resulting charge image over the first cross over voltage.
  • This charge image integration technique is described in greater detail in copending US. patent application Ser. No. 302,880, by Robert H. Anderson, filed Aug. 19, 1963, entitled Improved Storage Tube and Method of Operation.
  • the increase in the potential of the charge image achieved by preventing the holding or flood electrons from striking the storage target during writing is due to the fact that such holding electrons oppose the writing operation since they tend to drive the potential of the charge image downward to the voltage of the flood gun cathode. This opposing action continues until the potential of such charge image is increased above the first cross over voltage. After this the holding electrons aid writing by driving the potential of such charge image upward to the voltage of the collector electrode.
  • the writing speed enhancement technique described above is accomplished in FIG. 1 by means of a manual switch 44 having three different positions with its movable contact connected to the flood gun cathodes 31.
  • the fixed contact of switch 44 labeled WRITE is connected to a source of positive DC. bias voltage of about volts through an isolating resistor 46 so that the flood guns are cut off when the switch 44 is in the WRITE position due to the fact that the control grids 34 are connected to negative DC bias voltages of about 20 volts and such flood gun cathodes are therefore reverse biased by about volts. This prevents the flood electrons from bombarding the storage target 26 during the time the writing beam emitted by cathode 28 is producing the charge image on the storage target.
  • the flood gun cathodes are connected across a capacitor 48 having one terminal connected to ground and its other terminal connected to a source of negative D.C. supply voltage of about 70 volts through a fixed resistor 50 and a variable resistor 52 connected in series.
  • the capacitor 48 is initially charged to -70 volts bu current flowing through resistors 50 and 52 so that by moving the switch 44 to the STORE position the voltage on the flood gun cathode changes initially to 70 volts.
  • This causes the flood guns to be rendered conducting since their cathodes are then forward biased by 50 volts.
  • flood electrons are transmitted to the storage target of a higher voltage initially.
  • the capacitor 48 immediately begins discharging toward the voltage set at the common connection of such capacitor with resistor 50 to decrease the velocity of the flood electrons exponentially.
  • the voltage of the flood gun cathode 31 after discharge of capacitor 48 may be set to 0 by adjusting the setting of resistor 52 to vary the current so that the voltage drop across resistors 50 and 52 is 70 volts.
  • the storage tube 10 operates in a conventional manner to store the charge image.
  • An electrical readout signal may be produced on the target coating electrode by scanning the phosphor layer of the storage target with a reading beam of electrons as described in copending US. patent application Ser. No. 245,716, filed Dec. 19, 1962, by Robert H. Anderson and entitled Electrical Readout for Storage Tube, now Patent No. 3,219,316.
  • This reading beam may be produced by the same electron gun which provided the writing beam merely by changing the position of the switches 18 and 24 to the READ position indicated so that a raster signal generator 54 is connected to the horizontal and vertical deflection plates of tube 10 to move the beam in a TV raster pattern over the surface of the target.
  • the electrical readout signal produced on the conductive film of the storage target is transmitted through a coupling capacitor 58 to a low input impedance preamplifier 60.
  • the output of preamplifier 60 is connected through a conventional voltage amplifier 62 before being transmitted to the Z-axis input at the control grid or cathode of a remote TV monitor tube 64.
  • the horizontal and vertical deflection plates of the monitor tube 64 are also connected to the raster signal generator 54 so that the same or related saw tooth raster signals may be applied to these deflection plates as are applied to the horizontal and vertical deflection plates of the storage tube during the readout operation.
  • the wave form image stored on the storage target 26 is reproduced on the fluorescent screen of the monitor tube 64.
  • electrical readout is not necessary when a direct viewing storage target is employed but the present method may also be employed with storage tubes having nondirect readout targets.
  • the wave form image stored on the target 26 may be removed by a conventional erase operation merely by varying the resistor 33 so that the voltage across load resistor 32 is first increased above the fade positive voltage to enable the flood electrons to cause the storage target to fade uniformly positive. Then the target voltage is decreased below the first cross over or retention threshold voltage to cause the potential of the rear surface of the storage dielectric to be driven negative back to the voltage of the flood gun cathode. Next, the voltage across resistor 32 is slowly increased above the first cross over voltage so that the conductive film target electrode is provided with a voltage within the stage range without causing the rear surface of the storage dielectric to follow such target electrode voltage. This erase operation may also be accomplished by pulsing the target electrode.
  • flood gun cathode to a source of positive DC. bias voltage of, for example, about +50 volts during the erase operation. This may be accomplished by rotating the movable contact of switch 44 to the ERASE position.
  • the potential of the flood gun cathode during the operation of the tube of FIG. 1 is shown by the curve 66 in FIG. 2.
  • the writing rate enhancement pluse portion 68 is applied immediately after the WRITE operation during which the flood gun cathode is cut off.
  • This enhancement pulse 68 decreases to a negative voltage which may be substantially below the first cross over voltage and then rises in an exponential manner towards volts at a rate determined by the RC. time constant of the circuit including capacitor 48 and resistors 50 and 52.
  • the width of such enhancement pulse is approximately equal to 3 RC and should be inversely proportional to the voltage amplitude of such enhancement pulse.
  • a large voltage writing rate enhancement pulse will cause the background areas of the target to charge more rapidly in a positive direction due to the increased secondary emission caused by the greater velocity of the flood electrons so that the enhancement pulse must be terminated sooner to prevent the voltage of such background areas from exceeding the first cross over voltage.
  • the proper values of resistance and capacitors must be selected for resistors 50 and 52 and capacitor 48.
  • FIG. 3 Another embodiment of the method and apparatus for increasing the writing rate of the storage tube of FIG. 1, is shown in FIG. 3.
  • the flood guns 30 are automatically turned off at the start of the vertical input signal applied through the vertical amplifier 16 to the vertical deflection plates of the storage tubes. This may be accomplished by transmitting a portion of the vertical input signal through a sweep trigger generator 69 to produce trigger pulses at the start of such vertical signal which are transmitted to the horizontal sweep generator 22 to start the operation of such sweep generator in a conventional manner.
  • the sweep trigger generator 69 may also be connected to the input of a flood gun blanking multivibrator 70 to trigger such multivibrator so that it produces a negative voltage output pulse 72.
  • This negative output pulse is then transmit-ted to the control grid 34 of the flood gun and functions as a blanking pulse to reverse bias the cathode of such flood gun to cut 01?.
  • the blanking pulse 72 is terminated to return the control grid 34 to a more positive voltage so that the flood gun is again rendered conducting.
  • the voltage on the flood gun cathode 31 is equal to the 70 volts of the fully charged capacitor 48.
  • thi cathode voltage decreases as the capacitor discharges to a more positive voltage which may be set to zero by varying resistor 52 until the beam current produces a voltage drop of 70 volts across resistor 50 and 52.
  • the flood gun blanking pulse generator 70 may be a monostable multivibrator whose frequency is separately controlled so that it is considerably lower than the frequency of the input signal applied to input terminal 14 in order to enable charge image integration by maintaining the flood gun cut off during several successive cycles of such vertical input signal. However, it may also be desirable to connect the flood gun blanking pulse generator 70 as a bistable multivibrator which is triggered by sweep trigger pulses and is reverted to its initial stable state by a signal from the horizontal sweep generator corresponding to the retrace portion of the horizontal sweep signal so that the blanking pulse 72 is discontinued immediately after the horizontal sweep signal. This bistable flood gun blanking multivibrator may be desirable when operating the storage tube to store transient vertical input signals.
  • a different type of signal generator may be employed in place of the blanking multivibrator 70 and the output of this signal generator may be connected to the flood gun cathode 31 to apply a positive voltage blanking pulse as well as a writ ing speed enhancement pulse to such cathode without employing the separate pulse forming circuit of resistors 50 and 52 and capacitor 48.
  • the flood gun blanking pulse 72 produced by the apparatus of FIG. 3, is shown in time relation to the flood gun cathode voltage 74 in FIG. 4.
  • the flood gun cathode voltage gradually decreases from "0 to about -70 volts as the capacitor 48 charges.
  • the flood gun cathode voltage then increases from 70 volts to 0 volts as the capacitor 48 discharges.
  • This positive going portion of the flood gun cathode voltage 74 provides the writing speed enhancement pulse.
  • the flood gun blanking multivibrator 70 of FIG. 3 is provided with a lock out control which prevents such multivibrator from being retriggered during storage and until after the charge image has been erased from the storage target.
  • FIGS. A, 5B and 5C The effect of operating a storage target in accordance with the methods of the present invention is shown by the curves of FIGS. A, 5B and 5C.
  • the writing speed enhancement pulse applied to the flood gun cathode is in the form of a negative spike voltage 76 as shown in FIG. 5A
  • the best results are obtained. This is due to the separation of the charge image voltage 78 from the background voltage 80 of unwritten target areas by a greater amount Y when the charge image voltage exceeds the first cross over voltage V
  • the charge image voltage 78 differs from the background voltage 80 by a small amount X after such charge image is written on the storage target, but before the flood electrons strike such target.
  • the enhancement pulse 76 When the enhancement pulse 76 is applied to the flood gun cathode, the potential of the charge image and the potential of the background target areas begin to rise due to the charging action of the flood electrons. As stated previously, the charge image voltage increases at a faster rate than the background voltage due to the fact that it was initially at a higher potential. Therefore, at some time after the enhancement pulse is applied, the charge image voltage 78 and the background voltage 80 are separated by a greater voltage difference than X. This enables the enhancement pulse 76 to be terminated within a wider time range without causing background to fade positive since the charge image voltage 78 exceeds the first cross over voltage V much sooner than the background voltage. Of course, the writing speed enhancement pulse 76 must be terminated or decreased in voltage to such a value that it can no longer increase the background voltage above the first cross over voltage, before such background voltage exceeds V in order to cause bistable storage.
  • the flood electrons cause such charge image voltage to be driven upward to a high voltage stable state V which is slightly greater than the voltage applied to the collector electrode At the same time such flood electrons cause the background voltage 80 of the unwritten target areas charged to a potential below V to decrease in voltage to a potential approximately equal to thatof the flood gun cathode.
  • the width W of the rectangular enhancement pulse 82 is more critical than the width of the spike enhancement pulse 76, so that such rectangular enhancement pulse must terminate immediately after the charge image voltage 78' exceeds V
  • the maximum amplitude V of both of the enhancement pulses 76 and 82 may also exceed the amplitude of the first cross over voltage V because they are maintained above that voltage for only a short time.
  • a negative stair step enhancement pulse 84 is applied to the flood gun cathode. Since this stair step enhancement pulse is maintained at its maximum voltage V and does not return to 0 its amplitude must be less than that of the first cross over voltage V Also, the sum of the voltage V of the enhancement pulse and the initial voltage A of the charge image voltage 7 8" must be greater than the first cross over voltage, while the sum of V and the initial voltage A of the background voltage 80" must be less than the first cross over voltage. In other words, A must be greater and A less than the difference in the voltage AV between the stair step enhancement voltage V and the first cross over voltage -V in order to enable bistable storage.
  • the initial voltage difference X between the charge image voltage and the background voltage must be sufficient to enable the enhancement voltage 84 to cause the charge image voltage to exceed the first cross over voltage immediately without causing the background voltage to exceed the first cross over voltage.
  • any appreciable fiuctation in the voltage V of the enhancement pulse 84 would prevent the bistable storage of charge images of very low initial potential due to the fact that there is always some noise in the background voltage.
  • this noise voltage is less for smooth surface storage targets such as the phosphor storage target shown in copending US. patent application Ser. No. 180,457, described above, than it is for conventional direct viewing storage targets of the current transmission type employing a mesh structure, due to the fact that the thickness of the phosphor target is substantially uniform while the thickness of the mesh target varies considerably.
  • flood electrons may be allowed to strike target areas charged above such first cross over voltage at this time since they do not oppose writing in these areas. This may be accomplished by increasing the potential of the flood gun cathodes with respect to the rear surface of the target dielectric in the positive direction until it is slightly above the first cross over voltage. The potential of the control grid of the flood gun is also increased so that flood electrons are still emitted therefrom. However most of these flood electrons are collected by the Wall band electrodes 38 and no flood electrons strike the storage target except in those written areas which the writing beam has driven above the first cross over voltage. As in the other methods described above, the negative writing rate enhancement pulse is applied to the flood gun cathodes after the writing operation to enable flood electrons to strike all target areas. Therefore, the scope of the present invention should only be determined by the following claims.
  • a method of increasing the writing rate of a bistable storage tube comprising the steps of:
  • a method in accordance with claim 3 in which a substantially constant voltage is applied to a target electrode over which the storage dielectric is supported, during the time the holding electrons are prevented from striking the storage dielectric.
  • a method in accordance with claim 3 in which a repetitive input signal is applied to the tube to modulate the writing electrons and form a charge image of the input signal, and several successive cycles of said input signal are applied during the time the holding electrons are prevented from striking the storage dielectric to enable integration of the superimposed charge images of said succcessive cycles.
  • the enhancement voltage is a spike shaped pulse whose trailing edge decreases at a slower rate than its leading edge increases.
  • Electron image storage apparatus comprising:
  • a storage target including a secondary emissive storage dielectric capable of bistable storage
  • means including a holding cathode for bombarding said storage dielectric with low velocity holding electrons so that said holding electrons cause bistable storage of said charge image when its potential is above said first crossover voltage;
  • An apparatus in accordance with claim 9 which also includes means for preventing the holding electrons from striking the storage dielectric during the bombardment of said storage dielectric by said writing electrons to form the charge image.
  • An apparatus in accordance with claim 10 which also includes means for applying a repetitive input signal to the storage tube to modulate the writing electrons and form a charge image of the input signal, and for applying several successive cycles of said input signal to said tube during the time the holding electrons are prevented from bombarding the storage dielectric to enable integration of the superimposed charge images of said successive cycles.
  • An apparatus in accordance with claim 10 which also includes means for applying a substantially constant voltage to a target electrode over which the storage dielectric is supported.
  • An apparatus in accordance with claim 10 which includes a switch means for applying a negative bias voltage between the holding cathode and its control grid to cut off the flow of holding electrons to the storage dielectric, and for applying the enhancement voltage to the holding cathode.
  • the storage dielectric is a layer of phosphor material provided over a light transparent conductive film coated on the inner surface of the face plate of the storage tube.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
US659826A 1964-01-13 1967-04-07 Method and apparatus for increasing writing rate of storage tube Expired - Lifetime US3413513A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US659826A US3413513A (en) 1964-01-13 1967-04-07 Method and apparatus for increasing writing rate of storage tube

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US33737064A 1964-01-13 1964-01-13
US659826A US3413513A (en) 1964-01-13 1967-04-07 Method and apparatus for increasing writing rate of storage tube

Publications (1)

Publication Number Publication Date
US3413513A true US3413513A (en) 1968-11-26

Family

ID=23320290

Family Applications (1)

Application Number Title Priority Date Filing Date
US659826A Expired - Lifetime US3413513A (en) 1964-01-13 1967-04-07 Method and apparatus for increasing writing rate of storage tube

Country Status (7)

Country Link
US (1) US3413513A (nl)
JP (1) JPS5245187B1 (nl)
CH (1) CH421314A (nl)
DE (1) DE1272370B (nl)
FR (1) FR1422475A (nl)
GB (1) GB1085811A (nl)
NL (1) NL146979B (nl)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3693040A (en) * 1970-12-16 1972-09-19 Iwatsu Electric Co Ltd Method of reading bistable storage tubes by increasing luminescence where information is stored
US3798494A (en) * 1971-12-08 1974-03-19 Tektronix Inc Non-storage electron multiplier operation of transmission storage tube
US4232250A (en) * 1979-04-19 1980-11-04 Tektronix, Inc. No-flash erase of direct viewing bistable storage CRT
US4335380A (en) * 1980-06-16 1982-06-15 Wright David Y Multi-beam raster scan display monitor

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3259791A (en) * 1962-05-31 1966-07-05 Westinghouse Electric Corp Stored signal enhancement electron discharge device

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL90305C (nl) * 1950-07-20

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3259791A (en) * 1962-05-31 1966-07-05 Westinghouse Electric Corp Stored signal enhancement electron discharge device

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3693040A (en) * 1970-12-16 1972-09-19 Iwatsu Electric Co Ltd Method of reading bistable storage tubes by increasing luminescence where information is stored
US3798494A (en) * 1971-12-08 1974-03-19 Tektronix Inc Non-storage electron multiplier operation of transmission storage tube
US4232250A (en) * 1979-04-19 1980-11-04 Tektronix, Inc. No-flash erase of direct viewing bistable storage CRT
US4335380A (en) * 1980-06-16 1982-06-15 Wright David Y Multi-beam raster scan display monitor

Also Published As

Publication number Publication date
GB1085811A (en) 1967-10-04
NL6500398A (nl) 1965-07-14
CH421314A (fr) 1966-09-30
JPS5245187B1 (nl) 1977-11-14
NL146979B (nl) 1975-08-15
FR1422475A (fr) 1965-12-24
DE1272370B (de) 1968-07-11

Similar Documents

Publication Publication Date Title
US3710173A (en) Direct viewing storage tube having mesh halftone target and nonmesh bistable target
US3325673A (en) Charge integrating bistable storage tube
US3002124A (en) Display storage tube
US3413513A (en) Method and apparatus for increasing writing rate of storage tube
US2259506A (en) Cathode ray tube oscillograph
US2788466A (en) Direct-viewing storage tube
US3594607A (en) Direct viewing bistable storage tube having fast erase speed
US3611000A (en) Selective erasure of a bistable storage tube
US2998541A (en) Transmission storage tube
US3312850A (en) Relatively thick phosphor storage target having spaced holes for electron passage
US3430093A (en) Method of write-through operation of direct viewing bistable storage tube to produce nonstored image of high brightness during shortage of another image
US2967969A (en) Direct view storage tube with controlled erasure
US4139800A (en) Bistable storage target having interdigitated target electrode for selective erasure
US3277333A (en) Storage tube system and method
US2795727A (en) Direct-viewing electronic storage tubes
US3710179A (en) Storage tube having transmission target with low differential cutoff
US3408531A (en) Storage system
US2785328A (en) Storage tube
US2856559A (en) Picture storage tube
US3470414A (en) Direct view storage system
US3753129A (en) Stabilization of prepare voltage of transmission storage target
US3717786A (en) Post-deflection acceleration storage tube
US2931938A (en) Storage tube circuit
GB896544A (en) Improvements in or relating to signal storage tubes
US3317782A (en) Image intensifier storage tube