US3895371A - Display device - Google Patents

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Publication number
US3895371A
US3895371A US410568A US41056873A US3895371A US 3895371 A US3895371 A US 3895371A US 410568 A US410568 A US 410568A US 41056873 A US41056873 A US 41056873A US 3895371 A US3895371 A US 3895371A
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Prior art keywords
electrodes
source
pulse
discharges
display device
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Expired - Lifetime
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US410568A
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English (en)
Inventor
Tetsunori Kaji
Seiichi Murayama
Masakazu Fukushima
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Hitachi Ltd
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Hitachi Ltd
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N3/00—Scanning details of television systems; Combination thereof with generation of supply voltages
    • H04N3/10—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical
    • H04N3/12—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical by switched stationary formation of lamps, photocells or light relays
    • H04N3/125—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical by switched stationary formation of lamps, photocells or light relays using gas discharges, e.g. plasma
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J17/00—Gas-filled discharge tubes with solid cathode
    • H01J17/38—Cold-cathode tubes
    • H01J17/48—Cold-cathode tubes with more than one cathode or anode, e.g. sequence-discharge tube, counting tube, dekatron
    • H01J17/49—Display panels, e.g. with crossed electrodes, e.g. making use of direct current
    • H01J17/492—Display panels, e.g. with crossed electrodes, e.g. making use of direct current with crossed electrodes
    • H01J17/494—Display panels, e.g. with crossed electrodes, e.g. making use of direct current with crossed electrodes using sequential transfer of the discharges, e.g. of the self-scan type

Definitions

  • the present invention relates to a display device utilizing direct current or d.c. discharges in a gas, and more particularly to a display device employing a plurality of main discharges and a plurality of subsidiary discharges to facilitate the starting of said main discharges.
  • FIG. 1 One of hitherto known display devices has an arrangement of electrodes such as schematically shown in FIG. 1, in which reference numerals l-l, 1-2 and 1-3 indicate anodes for the main discharges, 2-1, 22 and 2-3 indicate cathodes common to the main and subsidiary discharges, while numerals 4-1, 4-2 and 4-3 represent anodes for the subsidiary discharges.
  • the cathodes 2-1, 22 and 2-3 have, respectively, through-holes 3-1, 3-2 and 3-3. All of the anodes l for the main discharges, the cathodes 2 and the anodes 4 for the subsidiary discharges are disposed in the atmosphere of the same type of gas.
  • the function of the subsidiary discharges is to facilitate the starting of the main discharges.
  • electrons or metastable atoms reach the main discharge space or chamber through the holes 3-1, 3-2 and 33.
  • the metastable atoms impinge upon the side wall of the main discharge chamber to cause secondary electrons to be emitted therefrom, which electrons enter the main discharge space to thereby increase the density of electrons therein, as a result of which a relatively lower voltage may be used as the discharge starting voltage.
  • FIG. 2 schematically shows in a partially broken perspective view a typical display device adapted to be energized by a three-phase pulse wave and having main discharge anodes 1 and subsidiary discharge anodes 4. It is to be noted that, while only respective ones of the main and subsidiary discharge anodes are shown in FIG. 2, all the other anodes are also arranged in the same manner.
  • reference numeral 5 indicates a voltage source for a reset operation
  • 6, 7 and 8 represent sources for the scanning pulses.
  • the cathode 2-1 is connected to the voltage source 5, while the pulse sources 6, 7 and 8 are connected to every third one of the other cathodes, respectively.
  • cathodes 2-2, 25, 28, etc. are connected to the voltage source 6, while the cathodes 2-3, 2-6, 2-9 etc. are connected to the voltage source 7.
  • the remaining cathodes 2-4, 27 and 210 etc. are connected to the voltage source 8.
  • the pulse voltages from one and the same pulse source are sequentially applied to every third one of the cathodes to thereby transfer successively the subsidiary discharge in a manner, so to speak, of scanning in three phases.
  • Reference numeral 9 indicates a pulse voltage source to produce signal voltages in accordance with the information to be displayed.
  • This voltage source 9 is connected to the main discharge anode 1-l by way of a resistor l 1.
  • a direct current source 10 is connected to the subsidiary discharge anode 4-1 through a resistor 12.
  • FIG. 3 graphically illustrates voltage wave forms of the reset source 5, the pulse sources 6, 7 and 8 for the three-phase scanning, the pulse source 9 and the dc. sources as well as the wave of the subsidiary discharging current (i flowing through the auxiliary anode 4-1, when the brightness modulation of the display device shown in FIG. 2 is performed by the voltage amplitude modulation.
  • the voltage from the pulse source 9 remains zero for-a period 7 after the scanning pulse voltages are applied from the voltage sources 6, 7 and 8. This period is termed the blanking period or duration.
  • T 1 after the blanking period 7 in the duration T of the scanning pulse voltage
  • a signal voltage is supplied from the pulse source 9 in accordance with the information to be displayed.
  • the purpose of providing the blanking period 1 is to exclude possible erroneous occurrence of the main discharge.
  • FIG. 4 shows characteristics of the discharge cells with the ordinate indicating the time t,, while the voltage difference V ,-V is taken along the abscissa.
  • Curve a represents the characteristic of the cell which is the most difficult to discharge, while the curve a is the characteristic of the cell most ready to begin discharge.
  • the dotted broken line extending in parallel to the abscissa indicates the period during which the voltage from the pulse source 9 is continuously applied. In the region above the dotted line, no main discharge can be produced. It is apparent from the graph of FIG. 4 that, in a low brightness region with the voltage V,, being at a low level, some cells produce main discharges, while others are not in the position to discharge, which thus results in the unevenness of the display brightness.
  • the broken line indicates the corresponding characteristics in case a sufficient number of initial electrons are available.
  • the curve b indicates the characteristics of the cell most difficult to discharge, while b represents the charactc ristics of the cell most ready to discharge. The difference in the time interval t, between the cells having characteristics b and b is reduced, which effect is attributable to the increase of the initial electrons.
  • the quantity or number of the initial electrons can be increased by increasing the current isd.
  • this method brings about the following drawbacks: (l) at first the amount of light leaking into the main discharge areas through the through-holes 3 is increased, whereby the background becomes brighter to deteriorate the contrast of the display; (2) the dissipation of the electrodes is accelerated by the spattering, resulting in the shortening of the life of display elements; and (3) the device becomes more susceptible to erroneous operations.
  • FIG. shows the relationship between the subsidiary discharge current (isd) and the minimum period (T min of the scanning pulse, which does not give rise to the erroneous operation. It can be seen from FIG. 5 that (T min becomes a minimum at a certain value of (isd) and increases at the other values of the latter. Accordingly, if the current (isd) is to be increased, the scanning rate must be decreased. Otherwise, erroneous operation may not be evaded. For this reason, the use of increased current (isd) is not a preferable measure.
  • An object of the present invention is to provide a display device of a high quality to display characters, numerals, figures, patterns or the like wherein the disadvantages and drawbacks of the conventional devices are substantially eliminated.
  • a pulse voltage source is used in place of the direct current source and the resistor 12 of the conventional display device shown in FIG. 2.
  • the dc. component of the subsidiary discharge current can be made smaller.
  • the delay time t, as well as the inequality thereof are considerably reduced.
  • FIG. 1 is a partial perspective view of an electrode arrangement of a known display device used for better understanding of the present invention
  • FIG. 2 schematically shows a structure of the conventionaldisplay device in a partial perspective view
  • FIG. 3 graphically shows wave forms of voltages and currents applied to various electrodes of the apparatus shown in FIG. 2;
  • FIG. 4 is a graph illustrating the relation between the applied voltage and the delay time of the discharge occurrence
  • FIG. 5 is a graph showing the relation between the subsidiary discharge and the minimum scanning pulse period
  • FIG. 6 is a perspective view showing schematically and partially a structure of a display device according to the present invention.
  • FIG. 7 illustrates a typical voltage wave applied to an anode for the subsidiary discharge in the device according to the invention
  • FIG. 8 is a graph to illustrate the relation between the main discharge voltage and the brightness of a display device manufactured according to the invention.
  • FIGS. 9 and 10 graphically show brightness characteristics of the devices embodying the invention.
  • FIG. 1 1 illustrates another example of a voltage wave as applied to an anode for the subsidiary discharge
  • FIGS. 12a, 12b and 120 and FIG. 13 are schematic circuit diagrams of pulse sources which can be employed in the embodiments of the invention.
  • FIG. 6 shows a main portion of an embodiment of the inventive display device
  • a pulse voltage source 10' is employed in place of the dc. source 10 and the resistor 12 of FIG. 2. It is to be noted that the same numerals in FIG. 6 indicate the same or equivalent elements to those shown in FIG. 2.
  • FIG. 7 shows graphically the wave forms of pulse voltage Vsd (two pulses are used in the illustrated example) applied to the anode for the subsidiary discharge from the pulse source 10' by way of a resistor (internal resistor contained in the source 10'), subsidiary discharge current (isd), and the scanning or transfer pulses from the source 6.
  • Vsd pulse voltage
  • FIG. 7 shows graphically the wave forms of pulse voltage Vsd (two pulses are used in the illustrated example) applied to the anode for the subsidiary discharge from the pulse source 10' by way of a resistor (internal resistor contained in the source 10'), subsidiary discharge current (isd), and the scanning or transfer pulses from the source 6.
  • Pulse I of the pulse voltage Vsd is used to produce initial electrons in the main discharge region, while pulse II serves to facilitate the transfer of the discharge in the subsidiary discharge area.
  • the pulse I can be applied to the subsidiary discharge anode 4-1 as a pulse having a relatively greater amplitude (for example, a. 2mA) for a predetermined duration as described hereinafter, so that the application of the pulse from the signal source 9 can bring about the main discharge without fail.
  • the pulse I plays a main role in rein accordance with objects to be displayed, images of 5 very high quality can be displayed.
  • FIG. 8 shows a result of the measurements of 2,000 discharge cells with respect to the relation between the brightness (fL) and the voltage (V) applied across the main discharge anode l and the cathode 2 with T of 6411s, 18,; of l9,u.s, rd. of l9us, 'rd of 62,us, rw and 7W2 both of 2p.s and the peak value i of (isd) set to 2 mA.
  • the unevenness of brightness among cells is neglected.
  • the applied voltage is expressed in terms of the excess voltage beyond the main discharge starting voltage.
  • Solid curves 0 and 0' show the characteristics of the display device according to the invention.
  • the curve c represents the cell most ready to discharge while the curve c is for the cell most difficult to discharge.
  • the dotted lines a and a are the characteristic curves of conventional display devices with the curve 0 for the most easily dischargeable cell and the curve 0 for the cell most difficult to discharge.
  • the maximum brightness of the display device was 13 fL.
  • the subsidiary discharge current on an average can be made smaller and thus the background brightness due to the leakage of light caused by the subsidiary discharge can be decreased to 0.2 fL which is lower than a half of the background brightness of the conventional device, which was 0.5 fL.
  • the contrast attained in the display device according to the present invention is therefore 65 l as expressed in terms of the ratio between the maximum and the minimum brightnesses.
  • the corresponding contrast in the case of the conventional device was 26 l.
  • the brightness at the lowest level which can be discriminated from the background was 0.4 fL at the excess voltage of 20 V.
  • the corresponding brightness level was 1.3 fL at the excess voltage of 37 V.
  • the number of gray scales determined by dividing linearly the brightness between the maximum and the minimum levels is 13 (fL)/0.4(fL) 32.
  • the number of gray scales was only l3(fL)/l.3(fL) 10. As is apparent, the ratio of contrast as well as the number of gray scales can be considerably improved.
  • FIGS. 9 and show results of the measurements concerning the pulse widths and phases of the pulses applied to the subsidiary discharge anodes 4.
  • FIG. 9 shows the relation between the pulse widths of the pulses I in FIG. 7 and the brightness.
  • the background brightnesses at the excess voltage OV applied to the main discharge electrode are indicated by a symbol and the background brightnesses at the excess voltage of 25 V are represented by A.
  • the main discharge is not initiated and the brightness is equal to the level at the excess voltage of CV (background brightness level).
  • the pulse having a pulse width greater than 1 us is impressed, a normal discharge will occur and the production of the normal gray scale is now possible.
  • FIG. 10 shows the relation between the brightness and rd of the discharge cell having the lowest brightness in the measurements shown in FIG. 9.
  • the value of *rw was 2 ,us. It was found that the brightness was at a maximum when rd was selected to be substantially equal to the blanking period rB The range of rd, in
  • FIG. 11 shows the voltage wave form in this case.
  • *rd and TW were the same as those obtained in the measurements shown in FIGS. 9 and 10.
  • the pulses I and II comprise, respectively, a single pulse. However, the same results could be obtained when the pulses I and/or II each composed of a plurality of pulses are employed.
  • FIGS. 12a, 12b show examples of the arrangements of the above-described pulse source 10.
  • the circuit of FIG. 12a is composed of a pulse generator 13 and a resistor 14.
  • the circuit of FIG. 12b comprises a pulse source 13, a transistor 18, a resistor 19 and a dc. source 20 connected to vary the current pulsewise.
  • a combination of the pulse source 13 and the dc. source 17 is employed together with resistors 14 and 16 and a diode 15 to superpose pulses on a small current.
  • the pulse source 10' employed in accordance with the present invention is not to be re stricted to these circuits. Any circuit arrangement which is capable of varying the voltage or current pulsewise may be used.
  • each of the subsidiary discharge anodes of the display device it is not preferable to provide pulse sources for each of the subsidiary discharge anodes of the display device, because the circuit connection is thereby much more complicated.
  • a circuit arrangement such as shown in FIG. 13 may be employed, when a number of the subsidiary discharge anodes are to be driven by the source circuit of the fundamental construction shown in FIG. 12c. Namely, each of the subsidiary discharge anodes is connected to a common pulse source 13 by way of a resistor and a diode 15.
  • the contrast of the image can be remarkably improved and the unevenness in the low brightness region can be greatly reduced.
  • an image display device of high performance has been accomplished.
  • a display device providing discharges in a gas, comprising a plurality of first electrodes for main discharges, a plurality of second electrodes for subsidiary discharges, a plurality of third electrodes disposed so as to intersect said first and second electrodes to produce said main and subsidiary discharges at the points of intersection in cooperation with said first and second electrodes, a gas-filled enclosure containing said first, second and third electrodes, a first electric energy source to supply a pulse wave to said third electrodes with a predetermined period to thereby transfer said discharges between third electrodes, a second electric energy source connected to supply a pulse wave having a predetermined period to said second electrodes to thereby produce said subsidiary discharge, and a third source connected to apply a signal to be displayed to said first electrodes to thereby produce said main discharges simultaneously with said subsidiary discharges.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Gas-Filled Discharge Tubes (AREA)
  • Transforming Electric Information Into Light Information (AREA)
US410568A 1972-10-27 1973-10-29 Display device Expired - Lifetime US3895371A (en)

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JP47107197A JPS5241013B2 (zh) 1972-10-27 1972-10-27

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US (1) US3895371A (zh)
JP (1) JPS5241013B2 (zh)
CA (1) CA999068A (zh)
DE (1) DE2353529C2 (zh)
NL (1) NL160431C (zh)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3981001A (en) * 1975-01-17 1976-09-14 Burroughs Corporation Multi-part display panel and system for operating the panel
US4021851A (en) * 1974-07-08 1977-05-03 Le Coquil Emile F Writing head for facsimile image reproduction
US4066929A (en) * 1975-01-24 1978-01-03 Hitachi, Ltd. Electron-acceleration type flatgas-discharge panel with internal memory functions and method of driving for same
US4325064A (en) * 1978-11-30 1982-04-13 Futaba Denshi Kogyo K.K. Driving circuit for a fluorescent display apparatus having fewer leads

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2702357A (en) * 1950-12-22 1955-02-15 Bell Telephone Labor Inc Multicathode gaseous discharge device
US3526711A (en) * 1966-09-30 1970-09-01 Philips Corp Device comprising a display panel having a plurality of crossed conductors driven by an amplitude to pulse width converter
US3654508A (en) * 1970-03-19 1972-04-04 Burroughs Corp Display panel having a plurality of display registers
US3681754A (en) * 1969-07-28 1972-08-01 Thomas L Baasch Self luminous shift register information display
US3727102A (en) * 1970-08-03 1973-04-10 Owens Illinois Inc Selection and addressing circuitry for matrix type gas display panel
US3795908A (en) * 1972-06-13 1974-03-05 Ibm Gas panel with multi-directional shifting arrangement

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2092441A5 (zh) * 1970-05-18 1972-01-21 Burroughs Corp

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2702357A (en) * 1950-12-22 1955-02-15 Bell Telephone Labor Inc Multicathode gaseous discharge device
US3526711A (en) * 1966-09-30 1970-09-01 Philips Corp Device comprising a display panel having a plurality of crossed conductors driven by an amplitude to pulse width converter
US3681754A (en) * 1969-07-28 1972-08-01 Thomas L Baasch Self luminous shift register information display
US3654508A (en) * 1970-03-19 1972-04-04 Burroughs Corp Display panel having a plurality of display registers
US3727102A (en) * 1970-08-03 1973-04-10 Owens Illinois Inc Selection and addressing circuitry for matrix type gas display panel
US3795908A (en) * 1972-06-13 1974-03-05 Ibm Gas panel with multi-directional shifting arrangement

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4021851A (en) * 1974-07-08 1977-05-03 Le Coquil Emile F Writing head for facsimile image reproduction
US3981001A (en) * 1975-01-17 1976-09-14 Burroughs Corporation Multi-part display panel and system for operating the panel
US4066929A (en) * 1975-01-24 1978-01-03 Hitachi, Ltd. Electron-acceleration type flatgas-discharge panel with internal memory functions and method of driving for same
US4325064A (en) * 1978-11-30 1982-04-13 Futaba Denshi Kogyo K.K. Driving circuit for a fluorescent display apparatus having fewer leads

Also Published As

Publication number Publication date
DE2353529A1 (de) 1974-05-16
NL160431B (nl) 1979-05-15
JPS4965729A (zh) 1974-06-26
NL7314793A (zh) 1974-05-01
DE2353529C2 (de) 1984-09-27
NL160431C (nl) 1979-10-15
CA999068A (en) 1976-10-26
JPS5241013B2 (zh) 1977-10-15

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