US3680049A - Display device and method for scanning said device - Google Patents

Display device and method for scanning said device Download PDF

Info

Publication number
US3680049A
US3680049A US70119A US3680049DA US3680049A US 3680049 A US3680049 A US 3680049A US 70119 A US70119 A US 70119A US 3680049D A US3680049D A US 3680049DA US 3680049 A US3680049 A US 3680049A
Authority
US
United States
Prior art keywords
column
light emitting
row
pulse
terminal
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
US70119A
Other languages
English (en)
Inventor
Toshihisa Tsukada
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.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
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 Hitachi Ltd filed Critical Hitachi Ltd
Application granted granted Critical
Publication of US3680049A publication Critical patent/US3680049A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
    • G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
    • G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
    • 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
    • H04N3/14—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical by means of electrically scanned solid-state devices

Definitions

  • ABSTRACT A display device comprising a number of light emitting diodes disposed in a matrix array, a switching element being connected in series with each of the horizontal (row) and the vertical (column) scanning lines; said array being scanned in such a manner that the column lines are scanned with a pulse consisting of a negative part and a subsequent positive part while the row lines which are always biased with a negative voltage of a value smaller than that of the said negative part of the column scanning pulse are scanned with a negative pulse of a value larger than that of the said negative part of the column scanning pulse, a trigger pulse being applied to the gate electrode of the switching elements in synchronization with the column scanning pulse for a column which includes a light emitting diode to be energized, thus a light emitting diode which has been transferred to a conductive state being returned to the non-conductive state by the negative
  • the conventional light emitter array which consists of a number of light emitting elements disposed in a matrix array, utilizes light emitting diodes (hereinafter, abbreviated as LED) as the light emitting elements; and the conventional method of scanning such an array for a lighted display is based on the principle that an LED connected at the cross point of the horizontal and vertical scanning lines that are being scanned emits light. With such a scanning method, an LED emits light only for a short instant during which the associated cross lines are being scanned. Therefore, in a large array con sisting of a large number of rows and columns, the lighting period of an LED is rendered to be a small fraction of the whole scanning period of the array, resulting in a display of insuflicient brightness.
  • LED light emitting diodes
  • the lighting period of a single diode is only 112,500 of a frame time, as LED has no persistency.
  • an apparent brightness the same as that of the ordinary cathode ray tube which is 50 foot Lamberts (hereinafter, abbreviated as f.L) or so, the brightness of each LED must be as high as 50X2,50(b 125,000 f.L. Such a high brightness cannot be expected from any known LED, much less the operation with low voltage and small current.
  • An object of this invention is to provide a light emitter array which is capable to exhibit the same overall brightness as that obtained by the above-mentioned line-at-a-time method without using any delay line, this being achieved by connecting an element having the switching characteristics in series with each of the row and column scanning lines of the array.
  • Another object of this invention is to provide a light emitter array having the same capability as mentioned in the preceding paragraph, by constituting the array with light emitting elements which per se have the switching characteristics.
  • a further object of this invention is to provide a method for scanning the above-mentioned arrays for the satisfactory operation, according to which a specially designed combination of scanning pulses are applied respectively to row and column scanning lines.
  • a still further object of this invention is to provide a method for scanning the array consisting of light emitting elements having the switching characteristics, which enables the light emitting element to be energized during most part of a scanning period and therefore to present a display of outstandingly high brightness.
  • FIG. I is a fundamental connection diagram of a light emitter array of the display device of this invention.
  • FIG. 2 is a diagram showing waveforms of the pulses applied to row and column terminals of the array shown in FIG. 1.
  • FIG. 3 is a diagram showing an alternative form of the pulse applied to the column terminals of the array.
  • FIG. 4 is a fundamental connection diagram of another embodiment of the light emitter array according to this invention.
  • FIG. 5 is a diagram showing waveforms of the pulses applied to row and column terminals of the array shown in FIG. 4.
  • indexes X,, X,, X,,,, X designate terminals of the row scanning lines of the number of M, indexes Y,, Y,, Y,,, Y terminals of the column scanning lines of the number of N, index G a gate terminal of the array, indexes SX,, 8X SX SX and indexes SY,, 8Y SY, SY elements having the switching characteristics such as silicon controlled rectifier elements (hereinafter, abbreviated as SCR) connected respectively to the row and column temtinals X,, X,, X,,,, X and Y,, Y ,...Y,,,...Y
  • SCR silicon controlled rectifier elements
  • FIG. 2 which shows waveforms of the row and column scanning pulses
  • the waveforms are presented on orthogonal coordinates, the abscissa standing for the time and the ordinate for voltage.
  • indexes FY FY FY, FY denote the waveforms of pulses to be applied to the terminals Y,, Y Y,,, Y and FX
  • M a m a 1) denote the waveform of a pulse to be applied to a terminal X,,,.
  • Voltage on each of Y Y Y,,, Y is normally at zero level, except that the voltage on Y, (N z n a l) is lowered to V at a time then raised to V;- at a and finally restored to zero level at t,,.
  • the time t,,' may be an arbitrary time between t,, and t,,. However, it will be understood that the time interval (t,.t,.
  • an SCR is used as each of the switching elements such as SX,, 8X SX,,,, SX, and SY,, 8Y
  • the SCR operates with a comparatively low voltage and small current. That is, it preferably be turned to conductive with a gate current at most l00p.A., the operating voltage inthe conductive state being 1 V or so.
  • the gate terminal G is connected with the control terminals of all SCR.
  • the cathodes of all row SCR and all column SCR are connected with the common line of the trigger circuit (not shown) respectively through a diode and a capacitor as shown in FIG. 1.
  • the SCR are controlled by a trigger signal applied to the gate terminal G. Assuming that the voltage applied to an LED is V and the hold voltage of the SCR is V the bias voltage level V L is set so as to be equal to 2V +V,,.
  • this circuit includes two SCR and one LED.
  • a voltage corresponding to V,,-V is first impressed across the terminals X, and Y,,.
  • a voltage VriVy is applied. If this voltage Vn+Vy is applied, theSCR elements which have been unconductive remain unconductive unless a trigger pulse is applied to the terminal G in synchronization with the voltage V'fi'Vy- Accordingly, no current flows through the LED.
  • a trigger pulse In order to cause a current to flow through the LED, a trigger pulse must be applied to the gate terminal G with an appropriate timing. Because of the switching characteristics of the SCR, the once triggered SCR remains conductive even after the time r,,,. In order to prevent any current from flowing through an LED which is connected with a row or column line that is not being scanned, the levels V and Vy are set so that when a voltage V i-V is applied across the terminals X, and Y,, the SCR is not turned to conductive even if the trigger pulse appears at the gate terminal G.
  • the voltage levels V and Vy and the height of the trigger pulse are chosen so that when a voltage V,,+V is applied across the terminals X and Y,,, the SCR is turned to conductive by the trigger pulse applied to the gate -terminal G.
  • V and V - are more preferred.
  • the same difference is desired to be as small as possible from the requirement thatthe amount of the light emission from an LED is not significantly affected bythe application of V
  • the once triggered LED is not returned to the non-conductive state until the associated column is scanned for the next time, when a negative voltage V appears at the terminal Y,,.
  • the bias voltage -V existing at the terminal X,,,, a negative voltage VL Vy is applied across the terminals X,.. and Y,,. Therefore, the SCR elements SX, and SY, are turned to nonconductive, and the LED at the cross point of both relevant lines is no more fed with the current.
  • the duration of the light emission of the LED corresponds to the time required for scanning a row, that is, r,,,-t,,,
  • the waveform of the column scanning pulses has been shown as rectangular waves. However, the waveform can assume other shapes.
  • An example of such waveforms is shown in FIG. 3, in which reference nu-- meral 7 designates a waveform of the output pulse from a shift register, and 8 a waveform obtained by differentiating the waveform 7 and this is the waveform usable for the scanning pulse.
  • Numerals 9, 10, ll designate voltage levels 0, Vy +Vy respectively.
  • the light emitting diodes are Ga As P diodes disposed in a 6mm spaced matrix array of seven rows by five columns; and the switching elements are SCR of type 2SF656.
  • Diodes of type 1S 79H and capacitors of l0p.F are inserted in the gate circuit as shown in FIG. 2.
  • the column scanning pulse is applied to the column terminals through a resistor of 2 k-ohm.
  • a current of 10 'mA. has been observed to flow through a light emitting diode in the conducting state.
  • a brightness of 9 f'L has been obtained.
  • the samearray scanned by the conventional method has presented a brightness of only 2 f-L.
  • FIG. 4 shows another embodiment of this invention.
  • light emitting diodes having the switching characteristics are used as the light emitting elements in the array.
  • terminals of similar functions to those shown in FIG. 1 are indicated with corresponding reference indexes.
  • the waveforms of the scanning signals may be essentially the same as those shown in FIG. 2,,though the peak values or levels of such signals may be different from those in the preceding embodiment depending on the characteristics'of the elements. Further, the manner of the operation is also essentially the same as that described in connection with the first embodiment.
  • the light emitter array shown in FIG. 4 can respectively to the column terminals Y,, Y,, ..Y,,, YM-
  • GX, (M :m a 1) denotes the waveform of the row scanning signal to be applied to the terminal X
  • Reference numerals 11, 12 respectively denote voltage levels zero and +Vy is the waveforms GY,, GY,, GY,, GY and numerals l3, l4, 15, 16 respectively denote, in the waveform GX,,,, levels zero, V,,, V,, and an arbitrary level which is not lower than Vy. It will be seen from the diagram that a voltage of constant level V; is normally applied to the row terminals;
  • the voltage is raised to the level not lower than Vy at a time t,, which is earlier by at least the time required for reversing the state of the element than the time t,,, when the scanning for the mth row begins, therebyrendering all the conducting elements in the mth row non-conductive, and then the voltage is lowered to the level V V,, V, at the time r,,, it being restored to the normal level V,, at the. time t...
  • the potential of the tenninals Y,, Y',, Y,, Y is normally at zero level.
  • a trigger pulse is applied to the gate terminal G in synchronization with thecolumn scanning pulse applied to the column associated with the element to be energized.
  • +Vy is first applied to the terminal X, during a period between t,,, and t ,,,.,to thereby make all elements in the mth row nonconductive. Then the potential of the terminal X, is lowered.
  • a voltage of vV Vy is applied to the element during a period between t,, and t,,. lfthe trigger pulse is not applied to the gate terminal G at this instant, the ele- .ment remains non-conductive and does not emit light.
  • the trigger pulse is applied, the element is turned to conductive and keeps emitting light until the mth row is. scanned for the next time. It may be noted that the duration of the light emission is slightly different for each column, the a is possible to visually equalize the unevenness of the brightness by arranging the sequence of the column scanning in a different mode from the geometrical sequence of the columns.
  • a sample of such a display device has been fabricated, in which PNPN type light emitting elements are disposed in a 6 mm spaced matrix array having seven rows and five columns. This array is scanned by the method described above in connection with FIG. 5.
  • the essential particulars for the operation are as follows:
  • the waveforms of the scanning pulses shown in FIGS. 2 and 5 have been simplified for easy understanding of the fundamental concept of this invention, and that pulses of other various waveforms can be used.
  • the width of the column scanning pulse is l/N of that of the row scanning pulse.
  • the width of the column scanning pulse can be optionally set, so far as it is longer than the time required for reversing the state of the element or otherwise conflicting in the timing relationship.
  • the pulse for making a conducting element non-conductive the negative pulses in FY,, FY FY,,, FY shown in FIG.
  • a display device comprising a light emitter array having a plurality of light emitting diodes disposed in a matrix array, a plurality of terminals each assigned to each of the rows and columns of the array, a plurality of elements having switching characteristics each assigned to each row of said array with the anode thereof connected with the cathode of every light emitting diode in the row and the cathode thereof connected with the terminal of the row, a plurality of elements having switching characteristics each assigned to each column of said array with the cathode thereof connected with the anode of every light emitting diode in the column and the anode thereof connected with the terminal of the column, and a gate terminal connected with the control terminals of all of said elements having switching characteristics.
  • a display device comprising a light emitter array having a plurality of light emitting elements that have switching characteristics, said elements being disposed in a matrix array, a plurality of terminals each assigned to each row of said array and each connected with the cathode of every light emittingelement in the row, a plurality of terminals each assigned to each column of said array and each connected with the anode of every light emitting element in the column, and a gate terminal connected with the control tenninal of very light emitting element in the array.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Led Devices (AREA)
US70119A 1969-09-12 1970-09-08 Display device and method for scanning said device Expired - Lifetime US3680049A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP7199269A JPS5028766B1 (enrdf_load_stackoverflow) 1969-09-12 1969-09-12

Publications (1)

Publication Number Publication Date
US3680049A true US3680049A (en) 1972-07-25

Family

ID=13476453

Family Applications (1)

Application Number Title Priority Date Filing Date
US70119A Expired - Lifetime US3680049A (en) 1969-09-12 1970-09-08 Display device and method for scanning said device

Country Status (5)

Country Link
US (1) US3680049A (enrdf_load_stackoverflow)
JP (1) JPS5028766B1 (enrdf_load_stackoverflow)
DE (1) DE2044909A1 (enrdf_load_stackoverflow)
FR (1) FR2068898A5 (enrdf_load_stackoverflow)
NL (1) NL7013330A (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3760373A (en) * 1971-12-20 1973-09-18 Ibm Optical data entry and display system
US4056733A (en) * 1976-01-02 1977-11-01 Combustion Engineering, Inc. Panel board
EP0410695A3 (en) * 1989-07-25 1992-09-02 Nippon Sheet Glass Co., Ltd. Light-emitting device
EP0335553A3 (en) * 1988-03-18 1994-01-05 Nippon Sheet Glass Co., Ltd. Self-scanning light-emitting element array
US5525810A (en) * 1994-05-09 1996-06-11 Vixel Corporation Self calibrating solid state scanner
US5545886A (en) * 1990-03-13 1996-08-13 Symbol Technologies Inc. Barcode scanner using an array of light emitting elements which are selectively activated

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2748725C2 (de) * 1977-10-29 1982-05-06 Brown, Boveri & Cie Ag, 6800 Mannheim Vorrichtung zur Ansteuerung einer Gruppe von Leuchtdioden

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3397388A (en) * 1963-12-20 1968-08-13 Ibm Matrix control circuit

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3397388A (en) * 1963-12-20 1968-08-13 Ibm Matrix control circuit

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3760373A (en) * 1971-12-20 1973-09-18 Ibm Optical data entry and display system
US4056733A (en) * 1976-01-02 1977-11-01 Combustion Engineering, Inc. Panel board
EP0335553A3 (en) * 1988-03-18 1994-01-05 Nippon Sheet Glass Co., Ltd. Self-scanning light-emitting element array
US5451977A (en) * 1988-03-18 1995-09-19 Nippon Sheet Glass Co., Ltd. Self-scanning light-emitting array and a driving method of the array
EP0917212A1 (en) * 1988-03-18 1999-05-19 Nippon Sheet Glass Co., Ltd. Self-scanning light-emitting element array
EP0917213A1 (en) * 1988-03-18 1999-05-19 Nippon Sheet Glass Co., Ltd. Self-scanning light-emitting element array
EP0410695A3 (en) * 1989-07-25 1992-09-02 Nippon Sheet Glass Co., Ltd. Light-emitting device
US5545886A (en) * 1990-03-13 1996-08-13 Symbol Technologies Inc. Barcode scanner using an array of light emitting elements which are selectively activated
US5912450A (en) * 1990-03-13 1999-06-15 Symbol Technologies, Inc. Bar code scanner utilizing time-multiplexed scan lines
US5525810A (en) * 1994-05-09 1996-06-11 Vixel Corporation Self calibrating solid state scanner

Also Published As

Publication number Publication date
NL7013330A (enrdf_load_stackoverflow) 1971-03-16
JPS5028766B1 (enrdf_load_stackoverflow) 1975-09-18
FR2068898A5 (enrdf_load_stackoverflow) 1971-09-03
DE2044909A1 (de) 1971-03-25

Similar Documents

Publication Publication Date Title
US4021607A (en) Video display system employing drive pulse of variable amplitude and width
US3733435A (en) Integral memory image display or information storage system
US3972040A (en) Display systems
US3647958A (en) Flat-panel image display with plural display devices at each image point
US4194215A (en) Method and apparatus for displaying a video picture on a matrix of light emitting elements
US3686661A (en) Glow discharge matrix display with improved addressing means
US3526711A (en) Device comprising a display panel having a plurality of crossed conductors driven by an amplitude to pulse width converter
GB1494792A (en) Method of driving matrix type liquid crystal display device
US3680049A (en) Display device and method for scanning said device
US3609747A (en) Solid-state display circuit with inherent memory
US4031541A (en) Color video display system
US4253044A (en) Gas discharge display panel, display apparatus comprising the panel and method of operating the display apparatus
US4296375A (en) Level indicator for indication of maximum values
GB1325165A (en) Display systems
US4408223A (en) Beam index color display system
US3754230A (en) Plasma display system
US3987337A (en) Plasma display panel having additional discharge cells of a larger effective area and driving circuit therefor
US3815120A (en) Gas discharge display apparatus having time multiplex operated anode and cathode driver circuits
GB1323577A (en) Information storage arrangements
KR100618293B1 (ko) 매트릭스 디스플레이 패널용 구동기 회로
US3393346A (en) Excitation circuits for an array of electrical elements
GB1506930A (en) Display systems
US4011558A (en) DC gas panel electrical display device
TW273614B (en) A method of driving storage devices for a plasma discharge plate
US3519880A (en) Electroluminescent image display system having improved horizontal scanning