Patent Publication Number: US-3878430-A

Title: Self shift display panel driving system

Description:
United States Patent Hirose 5] Apr. 15, 1975 [54] SELF SHIFT DISPLAY PANEL DRIVING 3.795.908 3/1974 McDowell et al 340/324 M SYSTEM [75] Inventor: Tadatsugu Hirose, Akashi, Japan Primary V. Rolinec [73] Assignee: Fujitsu Limited, Kawasaki. Japan Assistant EXaml&#39;n@r-E- ROChC [22] Filed: June 19, 1973 Appl. N0.: 371,477  
 Foreign Application Priority Data June 22, 1972 Japan 47-62768 U.S. Cl. 315/169 TV; 315/846; 315/323; 340/324 M Int. Cl H01j65/00; HOSb 41/30 Field of Search 315/846, 169 R, 169 TV, 315/323; 340/324 M References Cited UNITED STATES PATENTS Gaur ..3l5/l69RX [57] ABSTRACT A self shift display panel driving system in which a discharge spot produced by written information is shifted by sequential switching of an impression voltage; a stationary display of the written information by the discharge spot is provided by the application of the impression voltage to a predetermined electrode; and the shift action is effected at high speed and stabilized by the impression of a voltage higher than a sustain voltage for the stationary display.  
 11 Claims, 8 Drawing Figures PATENTEBAPR 1 5197s SHEET 1 BF 3 FIG. I PRIOR ART FIG.2.  
 Vsm  
 I X2 X3 X4 X5 X6 X? X8 PATENTEDAPR 1 5191s saw 3 5 3 91 SEE 3 9m mvwt SEE SELF SHIFT DISPLAY PANEL DRIVING SYSTEM BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a self shiftdisplay panel driving system in which display information is written while sequentially shifting a discharge spot.  
 2. Description of the Prior Art A self shift display panel has a construction such. for example. as depicted in FIG. I, in which electrodes w. a1, bl, (&#39;1, a2, are disposed on a first base plate I of glass and covered with a dielectric layer 2; electrodes vi and write electrodes Ri (i=1, 2, are disposed on a second base plate 3 and covered with a dielectric layer 4&#39;. and a discharge gas such as neon or the like is sealed in the space 5 defined between the base plates 1 and 3. The electrodes it. al, a2, bl, b2, and cl, (&#39;2, are connected to buses W. A. B and C. respectively, and the electrodes \&#39;1&#39; are interconnected. By the application of a write voltage higher than a firing voltage between a selected one of the write electrodes R1 and the electrode W. a discharge spot is produced at their intersecting point. Then. in such a state that the electrodes yi are all grounded or supplied with a predetermined voltage, the impression of a voltage between the electrodes vi and the bus A. which is slightly higher than the firing voltage of neighboring electrodes. which is lowered under the influence of the primary current effect by the first discharge spot pro duced between the electrodes R1 and W, causes a dis charge spot between the electrodes a1 and vi. Then. by impressing a similar voltage to the bus B and cutting off the voltage to the bus A, the discharge spot is shifted between the electrodes b1 and yi. Namely. the information written in the selected one of the electrodes Ri is shifted in the form of a discharge spot to the left. as seen in FIG. I, by the sequential voltage impression to the buses A. B and C. When the changeover of the voltage is stopped at a desired shift position. the discharge spot also is stopped on the electrode leading to the bus being supplied with the voltage at that time. thus providing a display in a stationary condition. Namely, in this type of self shift pane], it is possible to shift serially written information in the form of a discharge spot from one side of the panel and provide its stationary display at any time by making use of the memory function due to a wall charge.  
  There has also been proposed the so-called surface discharge type self shift panel which does not employ the electrodes yi in FIG. I and which is adapted such that a discharge spot is produced between adjacent ones of the electrodes a1, bl, c1, and shifted.  
  Incidentally, in the above-described self shift panel, it is necessary that wall charges remaining in the wall at positions corresponding to electrodes energized previously be sequentially erased in accordance with the shift operation. If the wall charge remains alive, when a voltage of the next cycle is impressed through the common bus. the discharge spot is likely to be produced again to cause an erroneous display although no information has been shifted to the corresponding intersecting point of the electrodes. To avoid this, it is the practice in the prior art to impress an erasing pulse to the preceding electrode at the instant the discharge spot is shifted to an adjacent electrode intersecting point or prolong the cycle of voltage changeover to such an extent as to be equal to the time necessary for neutralization and extinction of the wall charge; but, in either case. the shift action is unstable and high-speed shift is difficult.  
 SUMMARY OF THE INVENTION The present invention is to provide a novel self shift display panel driving system which is free from the aforementioned defects experienced in the prior art and which utilizes the fact that a firing voltage and a minimum sustain voltage at adjacentelectrode intersecting points differ in accordance with&#39;the magnitude of an impressed voltage, thereby ensuring and facilitating the shift action and automatically erasing a wall charge following each step of the shift action.  
  Briefly stated, the self shift display panel driving system of this invention is of the type in which a discharge spot is shifted by sequential changeover of an impression voltage and written information is displayed with a predetermined sustain voltage at any time and which is characterized in that the discharge spot is shifted while impressing a voltage higher than the sustain voltage for the display.  
 BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of the principal part of a prior selt shift display panel;  
  FIG. 2 shows characteristic curves for explaining the principle of this invention;  
  FIG. 3 is a circuit diagram illustrating an embodiment of this invention; and  
  FIGS. 4A and 4E show a series of waveforms for explaining the operation of the embodiment of FIG. 3.  
 DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention has found. in connection with such a self shift display panel as described previously. that where a discharge is being produced between opposing electrodes. the firing voltage and the minimum sustain voltage beween neighboring opposing electrodes are affected by the discharge in accordance with the magnitude of the impression voltage for the discharge. For example, in FIG. 2, where a discharge is being produced between the electrodes y and x1, if the impressed voltage therebetween is high, the firing voltage Vf and the minimum sustain voltage Vsm between the other adjacent electrodes become that as indicated respectively by the curves b and b, and if the impression voltage is low, they become as indicated by the curves a and a. Namely. if the impressed voltage is raised, the firing voltage Vf between adjacent electrodes y and .v2 lowers, for example, from Vfa to Vfb. allowing ease in the self shift action. At the same time, the minimum sustain voltage Vsm rises, so.that an increase in the voltage for discharging after shifting. decreases wall charges between previously energized electrodes to facilitate erasing of the wall charges. Further, the difference between the firing voltage between subsequent electrodes y and x3 and that between those y .\2 adjacent to them is A Ml when the impressed voltage between the electrodes y-and .vl between which the discharge spot is being produced is low and the difference is A M2 when the impressed voltage is high. The greater the difference A M becomes, the more stable the self shift action becomes. An increase in the impressed voltage causes an increase in the difference A M.  
  In order that the discharge spot being displayed stationary by the sustain voltage V1 between the electrodes and .rl may be shifted to electrodes y and .\2 by utilizing the above-described phenomenon. first a voltage V2 higher than that V1 is impressed between the electrodes and .\&#39;l, and y and .\&#39;2 to provide a discharge spot on the electrodes .\&#39;1 and .\&#39;2 in common; thus. first the voltages V1 and V2 are impressed to the electrodes .\&#39;1 and 12, respectively; and then the voltage impressed upon the electrode .\&#39;I is removed. Thus, the discharge spot is shifted and, at the same time. the discharge spot between the electrodes y and .\&#39;l is extinguished so that the wall charge is reduced. Consequently. the wall charge remaining in the wall at the position corresponding to the previous electrode .rl can be erased positively by a neutralizing action in a relatively short time or by the impression of an erasing pulse. Further, shifting of the discharge spot between the pair of electrodes y and .\&#39;2 to between electrodes y and .\&#39;3 also is achieved by similar procedures. This facilitates the shifting and ensures erasing of the remaining wall charge. In the prior art. the sustain voltage for the display operation and the shift voltage for the shift operation both are selected to be higher than the firing voltage at the position of adjacent electrodes subject to the primary current effect but, in the present invention. the impressed voltages V1 and V2 for both operations are different from each other.  
  FIG. 3 is a circuit diagram of one embodiment of this invention. which is shown to be applied to a self shift display panel SSP of two-dimensional shift. Reference characters V V V designate write pulse voltages; Va: a voltage of the bus W; V V and V voltages applied to the buses A, B and C; V V V and V voltages applied to buses D, AL, BL and CL; and  
 V1, V2 and V3 voltages shown in FIG. 2 are selected the buses AL. BL. CL and D serve as a display part 22.  
 In the input part 20, written information is shifted sequentially in a horizontal direction as seen in FIG. 3 and, in the display part 22, the information is shifted in a vertical direction as seen in FIG. 3 from the input part to provide a display.  
  During the shift action in the input part 20, the buses A, B and C are supplied sequentially with combined pulse voltages V V, and V of the voltages V1 and V2 and the buses AL, BL and CL are grounded through a transistor 03. In the shifting of the information to the display part 22, the buses AL, BL and CL are supplied sequentially with combined pulse voltages V V and V of the voltages V1 and V2 and the buses A, B, C and D are grounded through transistors Q2 and QD2. In the case of providing a stationary display in the input and display parts, the pulse voltages V and V or V,, and V of the voltage V1 are impressed only between the buses AL and A or between buses D and AL.  
  The voltages V1, V2 and V3 bear such a relation that V1 V2 V3. In the shift action in the input part 20, the voltages, for example, V and V are selected at V2 to facilitate shifting from the electrode connected with the bus B to that connected with the bus C. Then,  
 the voltages V, and V are selected at V1 and V2, respectively, and the impression of the voltage V is stopped to erase the discharge on the electrode connected to the bus B. In this case, after transistors QB2 and QC 2 are turned on to impress the voltage V2, transistors Q2 and Q4 are turned on to discharge the stored charges. Then. transistors Q81 and QC2 are turned on and transistors Q2 and Q4 are turned off. Thereafter, by repeating the same procedures, the discharge spot can be shifted from the electrode connected with the bus C to that connected with the bus A. Further, by repeatedly impressing the pulse of the voltage V1 to a desired bus, written information can be displayed stationary by the wall charge.  
  FIGS. 4A to 4E are a series of waveform diagrams for explaining writing and shifting in the input part 20. After transistors QRl QRi are turned on selectively by the written information to be supplied with a voltage -(V3Vl a transistor QRSl is turned on and then a transistor OR is turned on to be supplied with the voltage V1 and. further, a transistor QRS2 is turned on and, as a result of this, a voltage of a waveform V in FIG. 4A is impressed. Further, after a transistor QWl is turned on to be supplied with the voltage Vl, transistors Q2 and Q4 are turned on and a transistor QWZ is turned on to be supplied with the voltage V2, after which the transistors Q2 and Q4 are turned off and, further, the transistor QWZ is turned on and then the transistors Q2 and Q4 are turned on, thus impressing a voltage having a waveform Vw in FIG. 48 to the bus W. In thismanner, the write electrodes opposing the electrodes connected to the bus W are selected to produce a discharge. At the instant when the pulse of the voltage V2 has been impressed to the bus W. a transistor QB2 is turned on to impress the pulse V2 of the voltage V, to the bus B, performing the shift action. Thereafter, voltages of waveformes V,,,, V and V in FIGS. 4C to 4E are impressed by controlling the transistors 0A1, 0A2, QBl, QB2, QCI, QC2, Q2 and 04 as described above, by which the shift operation is achieved in a sequential order.  
  The vertical shift to the display part 22 is the same as described above and the voltages V V and V similar to the aforementioned are impressed to the buses AL, BL and CL by controlling transistors OARI, QAR2, QBRl, QBR2, QCRl, QCR2, QDl, Q1 and O3 to achieve thereby the shift operation.  
  In the case of a stationary display in the display part 22, the display is continuously provided with the voltage Vl as a sustain voltage by the control of the transistors QD, QD2, QARl and Q3.  
  As has been described in the foregoing, in the present invention, at the time of shift operation, the voltage V2 lower than a usual firing voltage but higher than the sustain voltage in the case of the stationary display is impressed to adjacent electrodes to facilitate shifting of the discharge spot, and in this case, the minimum sustain voltage of the adjacent electrodes is raised by the formation of the discharge spot by the impression of the voltage V2, but the voltage V1, which is higher than the usual sustain voltage but lower than the raised minimum sustain voltage, is impressed to the preceding electrodes to erase the wall charge, so that the shifting speed can be enhanced. Since the voltages V2 and V1 are different only in magnitude and can be made identical in pulse width with each other, the control is simple and easy as compared with the system of impressing an erasing pulse. Further. the circuit such as shown in FIG. 3 has theconstruetion of a low impedance circuit. so that voltage fluctuation due-to a discharge current is little and hence the operation is stable.  
  Numerous changes may be made in the abovedescribed apparatus and the different embodiments of the invention may be made without departing from the spirit thereof; therefore. it is intended that all matter contained in the foregoing description and in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.  
 What is claimed is:  
  1. An energizing system for a gas discharge display panel including a first base plate and a first set of electrodes disposed thereon. and a second base plate and second set of electrodes disposed thereon to traverse said first set of electrodes for defining a discharge region at each of the intersections of said electrodes of said first and second sets, and said first and second base plates confining a discharge gas therebetween, said display panel having the characteristics that a firing voltage of a first magnitude applied between said electrodes of said first and second sets causes a discharge spot in the discharge region and a sustain voltage of a second magnitude less than the first magnitude applied between said electrodes of said first and second sets sustains said discharge spot in the discharge region, said energizing system comprising:  
 means for supplying a shift voltage pulse of a third magnitude less than the first magnitude and greater than the second magnitude.  
 means for applying said shift pulse. in a given time interval. between the electrodes of said first and second sets defining a discharge region at which a discharge spot exists and which is to be shifted to an adjacent discharge region and simultaneously applying a shift pulse between the electrodes of said first and second sets defining said adjacent discharge region and, in a successive time interval, ap-  
 plying a shift pulse only to said electrodes defining said adjacent discharge region and thereby to shift the discharge spot to the said adjacent discharge region.  
  2. The energizing system as claimed in claim 1 wherein there is further provided means for applying a voltage pulse ofa lower magnitude than that of the shift pulse during said successive time interval between the electrodes of said first and second sets intersecting at said given discharge region from which said discharge spot was shifted, thereby to positively extinguish the discharge spot at said given discharge region.  
  3. The energizing system as claimed in claim 2, wherein said lower magnitude pulse is of the second magnitude.  
  4. The energizing system as claimed in claim 3, wherein there is further provided a plurality of first buss electrodes and said first set of electrodes is divided into a plurality of groups of electrodes, the corresponding electrodes of each of said groups being connected 6 to respectively associated ones of said plurality of first buss electrodes.  
  5. The energizing system as claimed in claim 4 wherein said sustain voltage applying means includes a first plurality of switch means, each connected to said sustain voltage supplying means for applying selectively the sustain voltage to a corresponding one of said first buss electrodes, and said shift pulse applying means includes a second plurality of switch means. each connected to said shift voltage pulse supplying means for applying selectively the shift voltage pulse to a corresponding one of said first buss electrodes.  
  6. The energizing system as claimed in claim 4, wherein there is further provided a plurality of second buss electrodes, and said second set of electrodes is divided into a plurality of groups of electrodes, corresponding electrodes of each of said groups of electrodes of said second set being connected to respectively corresponding ones of said plurality of second buss electrodes.  
  7. The energizing system as claimed in claim 6, wherein there is included a third plurality of switch means, each connected to a corresponding one of said second buss electrodes for applying the sustain voltage thereto, and a fourth plurality of switch means, each connected to a corresponding one of said second buss electrodes for selectively applying the shift voltage pulse thereto.  
  8. An energizing system for a gas discharge display panel including a first base plate and a first set of electrodes disposed thereon. and a second base plate and a second set of electrodes disposed thereon to traverse said first set of electrodes for defining a discharge region at each of the intersections of said electrodes of said first and second sets and said first and second base plates confining a discharge gas therebetween, said display panel having the characteristics that a firing voltage of a first magnitude applied between said electrodes of said first and second sets causes a discharge spot in the discharge region and a sustain voltage of a second magnitude less than the first magnitude applied between said electrodes of said first and second sets sustains said discharge spot in the discharge region. said energizing system comprising:  
 means for supplying said sustain voltage of the second magnitude;  
 means for applying said sustain voltage during predetermined time intervals. between the electrodes of said first and second sets defining a discharge region at which a discharge spot exists and which said discharge spot is to be shifted to a discharge region thereto;  
 means for supplying a shift voltage pulse of a third magnitude less than the first magnitude and greater than the second magnitude; and  
 means for applying said shift voltage pulse to the electrodes of said first and second sets defining said adjacent discharge region during at least the last of said predetermined&#39;time intervals in which the sustain voltage is applied to said discharge region at which said discharge spot exists, thereby to shift the discharge spot to said adjacent discharge region.  
  9. The energizing system as claimed in claim 8, wherein each of said first and second sets of electrodes includes first and second pluralities of said electrodes, and wherein:  
 said first plurality of electrodes of said first set traverses said first plurality of electrodes of said second set, defining discharge regions at the intersections thereof, and comprising an input portion of said display panel, and  
 said second plurality of electrodes of said first set traverses said second plurality of electrodes of said second set defining discharge regions at the inter- 7 sections thereof comprising a display portion of said display panel. 7 10. The energizing system as claimed in claim 9,  
 - wherein there is further provided a common write electrode disposed upon said first base plate and a plurality of write selection electrodes disposed upon said second base plate and traversing said common write electrode, each of said write selection electrodes being associated write selection electrodes.