CN1111833C - High brightness large LED display screen and its driving method - Google Patents

Abstract

The present invention belongs to display techniques for televisions, which is especially provided for the purpose of overcoming the problems that all the existing LED display screens are in dynamic driving modes and a luminous tube has insufficient luminance. The present invention is composed of a main control unit, a secondary control unit and a display unit, wherein the main control unit comprises a signal source, a synchronous signal and a luminance controlling voltage conveyer, and the secondary control unit comprises a video input part, a luminance regulating part and a row address generating circuit; the display unit comprises a high-speed analog switching circuit and a driving circuit. The scheme of the present invention is characterized in that the present invention uses a dynamic scanning and static driving mode, and therefore, the present invention has advantages of high integral luminance, no-stage regulation of gray scale, reasonable structural design and economy.

Description

High brightness, large LED display screen and driving method thereof

Technical field: the invention belongs to the display technique of video, it relates to the structure of driving method and this kind display screen of the dynamic scan static drive in a kind of large display screen.

Background technology: since the mid-80, large colour electronic display technology has obtained development at full speed, and the colour advertisement screen that the early stage magnetic that occurs is convertible can show 4 kinds of colors, though form various color graphicss and literal. it has adopted robot calculator control, but the terminal display element is an electromechanical, and the color kind is few, and pace of change is slow, can't show quick animation and video image, display screen itself is not luminous, and at the weak effect at night, this technology is eliminated.What occur later on is the display screen of full electronic, the large electronic display of Chu Xianing is that Sony corporation of Japan is built the earliest, adopt the fluorescence pixel pipe of hot cathode, it forms a full color pixel with red, green, blue three kinds of pixel pipes, be used for playing television image, have image quality preferably, but its existing problem is: 1. power consumption is big; 2. the fluorescent tube life-span is not long, thereby restricted in the use.The technology of ultra-high brightness LED light emitting diode obtains remarkable progress to the later stage eighties, has brightness height, bright in luster by the red and green large colour electronic display of forming with blue look LED diode, the advantage that power consumption is little, become the main flow of electronic display, and the large display screen of some other type, as projection TV, video wall etc., because brightness is low, can only be in the more weak indoor use of light.Though at present popular various types of LED display characteristics are arranged respectively, but required vision signal is all taken from the video signal of computing machine output, in the final drive circuit of LED, for showing the picture intelligence of different gray shade scales, a digital-to-analog conversion D/A circuit must be arranged, converting different digital signals to different aanalogvoltage goes the driving LED pipe to send the light of different brightness, because the D/A circuit cost is higher, can not all dispose one to each pixel pipe, and to realize whenever-individual pixel pipe continuous drive, luminous continuously, promptly realize its static drive, also need an independently data latches to be set for each picture element, therefore this will further increase cost, no matter be the type of drive that the final stage of the display screen of any type all adopts dynamic scan.Luminotron on the each point is only lighted a flash on scanning is swept like this, and the time is of short duration, is to extinguish state At All Other Times, and the performance of LED pipe can't be fully played, and the result is that the brightness on the screen does not reach requirement.

For the application this patent has carried out novel sex cords March nineteen ninety-five in Patent Office of the People's Republic of China, therefrom obtain the file of three pieces of correlation techniques:

" 1.CN1037423A matrix display ", its centre point is the skill that has proposed to be used for the arrangement wiring of the non-linear resistance that selected liquid crystal display is made up of many diodes in LCDs, increased and intersected the fault-tolerance that just can improve circuit behind two lines of round-robin greatly, can improve yield rate and reduced failure rate;

" 2.CN1033894A matrix display ", the scope of this patent is identical with precedent, but it has proposed new departure of common sparing diode in the cover non-linear resistance, and it can save the quantity of diode, reaches the purpose that reduces failure rate, improves yield rate;

" 3.US4652782 the drive system of matrix display panel ", this patent is applicable to array liquid crystal display, for solving long problem of required duration of charging of display element, reverse charging is carried out in the display element unification promptly refreshed principle, can realize rapid charge, realize the demonstration of high-speed and low-power consumption.

What above in a word three pieces of associated documents all related to is some technical schemes of matrix addressing, LCDs, and they do not relate to the structure of LED display, do not relate to the content of the driving method of LED display.

Yet, when on April 12nd, 2002 substantive examination, two pieces of United States Patent (USP)s of new discovery.Be respectively US5198803A (mandate on March 30th, 1993) and US3902078 (mandate on August 26th, 1975).Wherein US5198803A is the technology that more requires near this patent than the file that obtains three pieces of correlation techniques in the novelty search of entrusting March nineteen ninety-five Patent Office of the People's Republic of China to carry out.Therefore further specify at US5198803A " large-scale image display system " with multi-stage grey scale.

4.US5198803A " the large-scale image display system with multi-stage grey scale " great advantage is to utilize the maintenance effect of capacitor C to electric charge, might realize the static drive under the dynamic scan, overcome the problem of the LED display luminance shortage of common dynamic scanning.But the deficiency of this patent maximum is not jump out from the circle of LCD.Simply remove to drive large LED display screen with the mode that drives small-sized LCD.There are several problems, make that this patent in fact is difficult to realize.

A. at first, be the difference of liquid crystal display cells and LED light emitting diode.The two not only has greatest differences on geometric scale, electrical specification is also different fully.Liquid crystal display cells belongs to the device of driven, produce electric current hardly under the effect of two ends driving voltage, and the LED light emitting diode belongs to the device of current drives.The similar voltage stabilizing diode of the forward characteristic of LED light emitting diode, a little of both end voltage increase can produce great forward current.The MOS-FET driving tube then is voltage-controlled device, a little of voltage on the control grid increases and can produce bigger voltage at its drain electrode load (being the LED light emitting diode) two ends, thereby the very big electric current of generation, very easily cause the overcurrent of LED pipe to burn, and be not only luminous non-linear.Therefore, in the FIG.3 that this patent proposes, if the LED tubing like liquid crystal display cells, belongs to the device then no problem (danger that does not exist overcurrent to burn) of driven.But as mentioned above, the LED light emitting diode belongs to the device of current drives, and a little of two ends forward voltage increases and can produce great forward current.Therefore, in the output loop of LED pipe, a current-limiting resistance is indispensable.Resemble the Rs (it is not only a negative feedback resistor) among the FIG.1A, and in FIG.3, this current-limiting resistance has been cancelled but.If what FIG.3 represented is the indicator light circuit of a LED pipe,, still can allow the LED pipe normal luminous by careful selection G1.Yet FIG.3 provides the display unit circuit of a large LED display screen.In this case, each display unit circuit can not resemble the LCD integrated on a large scale on a substrate.That is to say, can not resemble the consistance that guarantees each display unit circuit the LCD.In fact, the dispersiveness of MOS-FET tube grid cut-in voltage also is bigger, adds the dispersiveness of LED light emitting diode forward voltage drop.So, can not find one and can satisfy the different G1 that require of each display unit.That is to say that the FIG.3 circuit can't guarantee the safety of large LED display screen, effectively work.So there is the defective of a principle in FIG.3.Being fit to the display unit circuit that large LED display screen requires should be FIG.1A, but because the deviation on author's understanding, in this patent, final employing be that the author thinks the better FIG.3 of performance.

B. secondly, be the whole type of drive of the large LED display screen that proposes of this patent.In FIG.5, as can be seen, when number of display elements was N*M, control circuit had M D/A converter to provide the capable signal of M to drive, and the selection of N column selection control signal driving N row is arranged, and then realized that whole screen drives.This type of drive is for LCD, though each D/A converter will drive numerous display units, the actual physics length of delegation has only several centimetres (now big tens centimetres only), the problem that does not exist long line to drive.But for large LED display screen, the actual physics length of delegation is several meters at least, even reaches tens meters.Transmit fast-changing wideband video signal with a D/A converter on so long distance, the problem that long line drives is serious.A large amount of reflected signals can flood normal signal, can't see normal image on screen.And the notion that this patent even company commander's line drive is not all mentioned.Simultaneously, the integrated type of drive of this LCD formula is to several ten thousand of whole screen, even a hundreds of thousands led display unit proposed the requirement that must keep consistency, and in fact this be difficult to realize.

C. it is more that this patent adopts D/A converter quantity, thereby cost is also higher.From FIG.7, each horizontal drive circuit all comprises a D/A converter and corresponding support circuit.The image that for example will show a 640*480 pixel then needs 480 D/A converter driving circuits.And this is nothing but the demand of monochromatic display screen.In fact, large LED display screen all is colored basically, so the actual demand amount is a 3*480 D/A converter driving circuit.For LCD, substrate much more integrated have the D/A converter driving circuit of same structure, cost is not obviously improved.Then to increase many independently D/A converter driving circuits for large LED display screen, cost is produced more significantly influence.Simultaneously, this patent adopts measures such as double display-memory and corresponding driving circuit to go to improve the speed that image shows in FIG7, and this has also further increased cost.And for having adopted signal to keep the large LED display screen of principle, this is unnecessary.Because for LCD, though all have one to keep electric capacity at each display unit, owing to be on integrated circuit, the capacity of each electric capacity has only several pf, hold facility to signal is limited, and therefore the refresh rate that image is shown still has certain requirement.But for large LED display screen, because the space is big, this keeps the capacity of electric capacity hundreds of to be arranged more than the pf, and is unquestionable to the hold facility of signal.Therefore the refresh rate that image is shown has not needed the display as other types, reaches 60-100Hz even higher.As long as there is 25Hz just can show the image of flicker free as film.

5.US3902708 the electrical schematic diagram of " analog switch " is seen FIG.7, though this patent is a high-speed analog switch mentioning this at the beginning, in fact this analog switch is applicable to professional blattnerphone.Its feature is a low noise, and for high speed, i.e. switch dynamic perfromance, and time domain or frequency-domain analysis that this patent is basic even all do not have.Therefore, this high speed is just for the control action of the tonal range of its work and blattnerphone.It can't be competent at several million even the two-forty of tens megahertzes switch the task of wideband video signal.And this analog switch belongs to the technotron switch, and its insulation resistance is than little two orders of magnitude of MOS type fet switch.Be unsuitable for as the sampling maintained switch.Therefore, it both be not suitable for patent US5198803A, was not suitable for this patent yet.

Summary of the invention: the LED display that the objective of the invention is to overcome before only adopts the mode of dynamic driving to make the problem of LED pipe of short duration luminance difference of running time.Though in documents 4, among the US5198803A " large-scale image display system " a solution has been proposed with multi-stage grey scale, but because this scheme is not jumped out the characteristics of LCD, on large LED display screen, realize having any problem the special static drive mode that proposes my large LED display screen.And provide a cover to adopt the organization plan of static drive mode large display screen.

By as above design, high brightness provided by the present invention, the driving method of large LED display screen, it has adopted the computer digit signal, the mode of movement of digital-to-analog conversion technology and dynamic scan, the signal of display screen is introduced point and is outputed to the D/A end of convert from the computer digit vision signal, vision signal before distributing, each pixel unit is converted to simulating signal, switching and distribution with the digital form control signal, finish the transmission of signal with analog form and pass through field effect transistor driven for emitting lights diode with static driving, maintenance electric capacity on the fet gate and the difference of the biasing resistor on source electrode ground connection, the mode that it is characterized in that its employing dynamic scan, realize static drive, comprise maintenance electric capacity in each display unit of this display screen, it adopts long line to drive and the sub-module control method, the VGA VT of the computing machine that induces one a little to connect of signal, in each branch control module, comprise one group of display unit, bag Chinese juniper high-speed analog switch in each display unit is by field effect transistor driven for emitting lights diode.

In this programme, realize the high brightness of the described driving method of claim 1, the feature of large LED display screen is that its main control unit is by signal source, vision buffer amplifier I and synchronizing signal and brilliance control voltage forwarder and adjustable brightness power supply constitute, its adjustable brightness power supply is made of the adjustable regulator block of three ends, its control end makes the manual control output voltage that is formed by the automatic control of light activated element control or adjustable resistance, the other end of regulator block is made up of the capacitor of input, its signal source comprises colour television set, video recorder, video disc player, the VGA output and the colour decoding separated in synchronization part of computing machine are formed, be provided with the signal source selector switch of five dpdt double-pole double-throw (DPDT)s during output, vision buffer amplifier I exports the signal amplification frequently of isolated trichromatic vision in order to long line, synchronizing signal and brilliance control voltage forwarder comprise the polarity adjustment of capable field sync signal and synthetic synchronously, after amplifying, exports by line driver with the synthetic single line of adjustable brightness electric current, main control unit is the adjusting control core of total system, being the source of each minute controlling unit clock signal and synchronizing signal, also is the signal source of each minute control unit video signal; Its branch control unit is by video input and brightness regulation part, the luminous point rank addresses forms circuit and forms, wherein the input of its video is by the vision buffer amplifier II of three looks synthetic with the DC voltage of control brightness again through coupling electric capacity separately, the adjusting part of its brightness proposes the DC component the synchronizing signal of single line through a resistance capacitance from long line interface, having protection on a base circuit exports the luminance voltage emitter-base bandgap grading with the triode of stabilivolt, through capacitance-resistance filter luminance voltage is added to three looks dc bias circuit separately again, the following inclined to one side resistance of its biasing circuit is adjustable, the electric adjustable resistance that last inclined to one side resistance is made up of a fixed resistance and a triode is formed in parallel, form the vision signal of band brilliance control voltage, it is to be received after separate the row field by row head line that its luminous point rank addresses forms circuit, carry out the phase place adjustment synchronously for row, it is provided with synchro control oscillator kind signal when obtaining, with make a gift to someone the respectively clear terminal of column address counter and line address counter of a row signal that separates, crystal oscillation clock signal X is sent to the counting end of address counter, the row signal is sent into the counting end of line address counter, column address counter is through the A of three low levels of buffering driver output, B, the column address signal of C is A0, A1, A2, A3 produces each row left column signal during for low level, A3 produces the right column signal of each row during for high level, this with regard to may command about each 8 row totally 16 column signals, the high eight-bit of column address connects 8 and ranks address comparator, four capable signals of low level of line address counter output, its high eight-bit connects 8 row address comparers, choose the back positive pulse that is produced with the column address comparer, low four the capable signal A12 that swings to pulse and row address that the row address comparer is chosen, A13, A14, A15 sends into four of two three to eight code translators compositions and arrives the selection of sixteen bit code translator work row, the 4th signal A3 of the capable signal of selecting and the low level of column address counter sends into the selection that two to four code translators carry out row about each row, promptly finish rank addresses and select, each divides the control unit controls N*N display unit; Its display unit is made up of the driving circuit of high-speed analog switch and LED luminotron, position and row address were received respectively on one to eight high-speed analog switch of three looks to drive the luminotron on each picture element about it added selected column address, its driving circuit is that the vision signal of band brilliance control is delivered on the grid of field effect transistor, maintenance electric capacity is arranged between grid and the ground, the source class resistance grounded, luminotron of all kinds is the load of field effect transistor on each picture element, three kinds of colors of its display element are red, green, blue luminescent diode is provided with different quantity by the requirement of luminance balance, can adopt typical two red luminotrons, the pixel pipe of a green luminotron and a blue look luminotron.

Adopt this programme can embody following superiority: 1. to adopt new driving circuit, use field effect transistor safety driven for emitting lights pipe, maintenance electric capacity is arranged on its grid circuit, except that the instantaneous ignition of choosing in scanning, before choosing,, increase the working time of luminotron next time, can significantly improve the brightness of screen by keeping electric capacity to keep the field effect transistor conducting, perhaps under the condition that guarantees equal brightness, can adopt more cheap LED pipe, can reduce cost significantly; 2. owing to realized the breakthrough of static drive, simulating signal can change continuously, realize stepless grey scale change easily, and general display screen system generally can only be realized 16 grades gray scale adjustment for reducing cost, and has created the condition of being convenient to use; 3. after signal source was selected, its row field signal was synthetic, was merged into the long line transmission of a single line again with the d. c. voltage signal of adjustable brightness power supply, and it had both reduced failure rate, has simplified plate face structure, can also reduce cost; 4. this programme has adopted each to divide the control unit to be made of 16 * 16 picture elements, it is 0.5 meter * 0.5 meter that each unit accounts for display panel, if adopt 6 meters * 4 meters screen, its column address has only 12 groups, but its row, column address counter capacity is 12, its row, column ground batch comparer capacity is 8, so this programme has very big capacity reserve, adapts to the needs that the ultra-large type display screen is built fully; The selection of column address adopt three and about the mode of row, in display unit, can select eight high-speed analog switch for use, reduced cost, be a kind of selection of optimization.

Description of drawings: Fig. 1 is the electrical schematic diagram of the main control unit of this programme large LED display screen.

Fig. 2 is the electrical schematic diagram of branch control unit.

Fig. 3 is the electrical schematic diagram of display unit.

Fig. 4 is the electrical schematic diagram of adjustable brightness power unit in the main control unit.

Embodiment: the embodiment of existing accompanying drawings this programme.Signal source comprises colour TV, video recorder, video disc in main control unit, they can through colour decoding synchronously, the trichromatic vision that obtains analog quantity after the separating digital signal of signal and row frequently.They also can be delivered to computing machine ten multimedias and export through VGA, the pulse signal of the three primary colours simulating signal of video and row field, select through the selector switch that five cuttves two are thrown, trichromatic vision signal frequently amplifies the long line conveying of reserve through vision buffer amplifier I with it, row field signal is earlier through the polarity adjustment, by adopting negative absolute value circuit to convert the negative polarity signal to the positive polarity of computing machine or the synchronizing signal unification of negative polarity in the future, carry out the signal superposition by logic gates and door then and realize synthesizing synchronously, amplify output through line driver again.Adjustable brightness power supply is to be barricaded as by the adjustable regulator block of three ends (as L M317), the adjustable control terminal voltage, and the voltage divider that feeds back by output terminal comes control output voltage.The DC voltage of this output is exactly the dc offset voltage of the whole screen mean flow rate of control.By the RC coupled circuit that DC voltage and synchronizing signal is synthetic, to transmit with a single line, it can be simplified the plate face, reduce failure rate.Main control unit is the long line transmission interface between defeated state end of computing machine V GA and the LED display in a word.

For the ease of installation and maintenance, entire display screen adopts modular construction, is made up of the basic module of 16 * 16 picture elements, promptly is called branch control unit.Three look R, G, the B separating video signal sent by main control unit, deliver to each branch control unit of whole LED screen simultaneously, but which divides the control unit pixel should accept this vision signal constantly, depends on that then this divides control unit residing row number and row number on large-size screen monitors whether to be consistent with the video luminous point present position that main control unit sends.The residing column position of luminous point is relevant with the length that each line frequency begins the back time on the screen, and the line position of luminous point is relevant with the time length after the beginning.Divide the control unit by video input and brightness regulation partly and the luminous point rank addresses form circuit and formed.The video importation is made of the vision buffer amplifier II of three high input impedances, low output impedance, each road video output terminals is connected to dc bias circuit, the resistance of biasing resistor just can change the DC level of video output terminals by regulating up and down, thereby changes the overall brightness of screen.The following inclined to one side resistance of biasing circuit is adjustable resistance, go up inclined to one side resistance by a fixed resistance and-electric adjustable resistance that individual npn triode is formed is formed in parallel.After synchronous input end is through RC filtering, synchronization pulse is by filtering, only kept the DC level in the signal, therefore a brightness direct-current control voltage has appearred in the output terminal at luminance voltage, this voltage is again through being added to the base stage of electric adjustable resistance triode after the RC filtering, can change the conduction resistance value of diode by the variation of luminance voltage, promptly changed the whole resistance that inclined to one side resistance, the DC level of video output terminals is changed, and the overall brightness of the high more then screen of this DC level is big more.Form in the circuit in the luminous point rank addresses, if the horizontal synchronizing pulse cycle of the VGA vision signal of input is 32 μ S, wherein transmitting the time that vision signal takies is about 26 μ S, if this display screen is 6 * 4 meters, the pixel line density is 32 point/rice, then horizontal direction pixel number is 6 * 32=192 point, the time t=line period that each pixel takies (26 μ S)/horizontal direction pixel number (192)=0.1354166 μ S/ point, the clock frequency f=1/t=7.3846153MHz of this time point column address counter, that is to say each oscillation period, it is t=0.1854166 μ S that the cyclic address change of counter output, corresponding luminous point move time of one.The synchronization pulse of synchronous input end input is delivered to capable field synchronization separation vessel through long line receptacle, utilize the frequency difference of row, field pulse to be separated into Hang Hechang synchronizing pulse separately again, be expert at and adopt in the clock circuit RC variable delay circuit that line synchronizing phase is adjusted, so that adjust because the variant and problems of locking phase that transmission line length difference causes.Line synchronizing signal is delivered to capable synchro control crystal oscillator, make the vibration and the synchronous phase-locking of row of output.Simultaneously, each horizontal synchronizing pulse all makes the column address counter zero clearing.So time clock of every generation, the column address of counter output just adds one, make luminous point move in the horizontal direction one, column address from 0-191. in like manner in line period, field system chronizing impulse makes the zero clearing of luminous point row address register at every turn, horizontal synchronizing pulse of every then appearance, the row address of row address register output just adds one.In expert address of field duration from 0-500. because basic display unit is 16 row * 16 row, so 4 row, column address date need respectively be provided display unit.Development is considered by capacity, the rank addresses counter is all got 12, its low four A0, A1, A2, A3 is a column address, the A4-A12 high eight-bit is high-order column address or high-order row group number, its A12, A13, A14, A15 is low four row addresses, A16-A23 is high-order row address or high-order row group number, OK, the defeated attached high eight-bit of column address is sent into the comparer of eight row and column respectively, the data that eight toggle switches of the opposite side of comparer input are set, the data that toggle switch is set in the row and column comparer should with the row of this unit on entire display screen, the column position data are consistent.Positive pulse of this comparer output represents that this unit is selected when two comparers are all exported positive pulse when the data consistent of both sides.A12-A15 is low 4 row addresses, delivers to four to 16 the decoder of being made up of two three to eight code translators, controls the capable selection of 1-16 of display unit.Rank the high level Enable Pin G that comparer output positive pulse is delivered to four to 16 code translators when eight, and the positive pulse of 8 capable comparer outputs is when phase inverter is delivered to the low level Enable Pin R of four to 16 code translators simultaneously, and this code translator is enabled then to produce to go effectively and selects signal.Low three A0-A2 of A0-A3 column address are called A, B, C signal through behind the buffering drivers, can control the work of one to eight analog switch, A3 then control all each row about two to four code translators of row.0 exportable low level of left column of each two to four code translator when A3=0,1 of each code translator exportable low level when A3=1, but the restriction of the low level signal of the row that each two to four code translator is also chosen, so in 16 two to four code translators of 16 row, have only one two to four code translator to be enabled, promptly finally can only have the picture element of certain a certain row of delegation to be driven at every turn at every turn.Its display unit is made of the driving circuit of high-speed analog switch and luminotron.In the high-speed analog switch circuit, in each row the vision signal of each look is formed one to 16 high-speed analog switch by two eight analog switch, every row has Zuo Balie and right eight row, have six one to eight high-speed analog switchs, 16 row are totally 96 high-speed analog switchs, in these switches, send into the vision signal of VB, VG, VR and A, B, C column address signal simultaneously, under the combined action of each row left and right sides column signal, some speed-sensitive switches are enabled, the vision signal of analog quantity is delivered in the luminotron driving circuit of this point.Deliver to the grid of field effect transistor when vision signal, make Lou, produce the Ids electric current that is proportional to video amplitude between the source, make the LED pipe luminous, the time of its moment conducting is 0.135 μ s, it should be to extinguish state to the time between this point in next field scan, but keep electric capacity owing to be connected to sampling at grid circuit t, and fet gate input resistance and analog switch to cut-off resistance high, generally all greater than 10000M ohm.Therefore drive signal voltage remains unchanged substantially during this period, has realized static drive.

The design of circuit and element are selected in line with dependable performance in this programme, guarantee development needs, reducing cost is principle.The address counter of row and column respectively selects for use 3 74LS163 to be barricaded as.8 row, column address comparators are selected two 74LS85 or a 74LS688 for use.Four to 16 code translators that row is selected select for use two 74LS138 to be barricaded as.The left and right sides column selection of each row has adopted eight two to four code translator 74LS139 to be barricaded as.High-speed analog switch has selected for use 96 74HC4051 to be barricaded as, and field effect transistor is selected 768 of miniwatt VDMOS field effect transistor, IDM＞=0.1A, the pipe of VDS＞=30V for use.

The display screen technology of this programme is good through simulated experiment proof performance, and brightness height, gray scale can reach stepless variation, have rational in infrastructure, lower-cost characteristics in addition.

Claims (4)

1. high brightness, the driving method of large LED display screen, it has adopted the computer digit signal, the mode of movement of digital-to-analog conversion technology and dynamic scan, the signal of display screen is introduced point and is outputed to the D/A end of convert from the computer digit vision signal, vision signal before distributing, each pixel unit is converted to simulating signal, switching and distribution with the digital form control signal, finish the transmission of signal with analog form and pass through field effect transistor driven for emitting lights diode with static driving, maintenance electric capacity on the fet gate and the difference of the biasing resistor on source electrode ground connection, the mode that it is characterized in that its employing dynamic scan, realize static drive, comprise maintenance electric capacity in each display unit of this display screen, it adopts long line to drive and the sub-module control method, the VGA VT of the computing machine that induces one a little to connect of signal, in each branch control module, comprise one group of display unit, bag Chinese juniper high-speed analog switch in each display unit is by field effect transistor driven for emitting lights diode.

2, a kind of high brightness of realizing the described driving method of claim 1, large LED display screen, the main control unit that it is characterized in that it is by signal source, vision buffer amplifier I and synchronizing signal and brilliance control voltage forwarder and adjustable brightness power supply constitute, its signal source comprises colour television set, video recorder, video disc player, the VGA output and the colour decoding separated in synchronization part of computing machine are formed, be provided with the signal source selector switch of five dpdt double-pole double-throw (DPDT)s during output, vision buffer amplifier I exports the signal amplification frequently of isolated trichromatic vision in order to long line, synchronizing signal and brilliance control voltage forwarder comprise the polarity adjustment of capable field sync signal and synthetic synchronously, after amplifying, exports by line driver with the synthetic single line of adjustable brightness electric current, main control unit is the adjusting control core of total system, being the source of each minute controlling unit clock signal and synchronizing signal, also is the signal source of each minute control unit video signal; Its branch control unit is by video input and brightness regulation part, the luminous point rank addresses forms circuit and forms, wherein the input of its video is by the vision buffer amplifier II of three looks synthetic with the DC voltage of control brightness again through coupling electric capacity separately, the adjusting part of its brightness proposes the DC component the synchronizing signal of single line through a resistance capacitance from long line interface, having protection on a base circuit exports the luminance voltage emitter-base bandgap grading with the triode of stabilivolt, through capacitance-resistance filter luminance voltage is added to three looks dc bias circuit separately again, the following inclined to one side resistance of its biasing circuit is adjustable, the electric adjustable resistance that last inclined to one side resistance is made up of a fixed resistance and a triode is formed in parallel, form the vision signal of band brilliance control voltage, it is to be received after separate the row field by row head line that its luminous point rank addresses forms circuit, carry out the phase place adjustment synchronously for row, it is provided with synchro control oscillator kind signal when obtaining, with make a gift to someone the respectively clear terminal of column address counter and line address counter of a row signal that separates, crystal oscillation clock signal X is sent to the counting end of address counter, the row signal is sent into the counting end of line address counter, column address counter is through the A of three low levels of buffering driver output, B, the column address signal of C is A0, A1, A2, A3 produces each row left column signal during for low level, A3 produces the right column signal of each row during for high level, this with regard to may command about each 8 row totally 16 column signals, the high eight-bit of column address connects 8 and ranks address comparator, four capable signals of low level of line address counter output, its high eight-bit connects 8 row address comparers, choose the back positive pulse that is produced with the column address comparer, low four the capable signal A12 that swings to pulse and row address that the row address comparer is chosen, A13, A14, A15 sends into four of two three to eight code translators compositions and arrives the selection of sixteen bit code translator work row, the 4th signal A3 of the capable signal of selecting and the low level of column address counter sends into the selection that two to four code translators carry out row about each row, promptly finish rank addresses and select, each divides the control unit controls N*N display unit; Its display unit is made up of the driving circuit of high-speed analog switch and LED luminotron, position and row address were received respectively on one to eight high-speed analog switch of three looks to drive the luminotron on each picture element about it added selected column address, its driving circuit is that the vision signal of band brilliance control is delivered on the grid of field effect transistor, maintenance electric capacity is arranged between grid and the ground, the source class resistance grounded, luminotron of all kinds is the load of field effect transistor on each picture element

3. according to the described LED display of claim 2, the adjustable brightness power supply that it is characterized in that it is made of the adjustable regulator block of three ends, its control end makes the manual control output voltage that is formed by the automatic control of light activated element control or adjustable resistance, and the other end of regulator block is made up of the capacitor of input.

4. according to the described LED display of claim 2, the three kinds of colors of display element that it is characterized in that it are red, green, blue luminescent diode is provided with different quantity by the requirement of luminance balance, adopt typical two red luminotrons, the pixel pipe of a green luminotron and a blue look luminotron.

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