CN1003973B - Video display system - Google Patents

Abstract

The present invention relates to a video display system which comprises a group of display units, a video signal source used for providing a digital video signal and a pulse width modulator, wherein the display units are ranged according to an X-Y matrix, and the pulse width modulator is connected with the video signal source and can deduces a required pulse width modulation (PWM) signal according to the brightness level of the digital video signal. The pulse width modulator comprises a counter, a clock signal generator and a signal transmission circuit, wherein the counter uses the digital video signal as a data signal, the clock signal generator provides a clock signal for the counter, and the signal transmission circuit is connected with the pulse width modulator and used for providing a PWM signal for a display device in order to display an image on the display deice.

Description

Video display system

Briefly, the present invention is relevant with video display devices, specifically, the invention relates to a kind of like this video display system, in this display system, display unit is arranged by the X-Y matrix form in other words conj.or perhaps by two dimensional form, and for showing required image, above-mentioned display unit is encouraged by desired data (vision signal) respectively.

The video display devices of now having used, its display unit is arranged by the X-Y matrix form, and for showing required image, these display units are encouraged by desired data respectively.

Same applicant has proposed can be used for the following display unit of above-mentioned video display devices.

With reference to figures 1 through accompanying drawing 4, the profile that they are respectively the front views of fluorescence display unit, cut off along the A-A line, the perspective view after profile that cuts off along the B-B line and display unit partly cut.In these figure, the glass envelope of label 1 expression display unit, they are made of header board 1A, bonnet 1B and sidewall 1C.One group of fluorescence display segment 2(2R, 2G, 2B are housed in glass envelope 1 the inside), one group of negative electrode K(KR, KG, KB relative with above-mentioned fluorescence display segment is arranged) and one group of corresponding first grid G1(G _1R, G _1G, G _1B), and a public second grid (accelerating electrode) G2.On the display segment each section all is to be made of the phosphor layer that is coated on the glass front plate 1A inwall.Have three display segment 2R, 2G and 2B on inwall, they send respectively corresponding to three kinds of red, green, blue fluorescence.Do more detailed description below with reference to accompanying drawing 5, carbon coating 3 is conductive layers, and it is that form with frame is printed on the inwall of header board 1A.Fluorescent material with red, green and blue look adopts the method for printing to be coated in the carbon coating 3 formed frames to form display segment again.Phosphor layer also partly is overlapped on the carbon coating 3.Above-mentioned phosphor layer is topped by metal back layer (being the aluminizing layer) institute by one deck glued membrane again.

In addition, corresponding display segment 2R, the 2G that above-mentioned phosphor layer constituted, 2B are furnished with filamentary cathode KR, KG, KB and first grid G on bonnet 1B inwall _1R, G _1GAnd G _1BOn the inwall of same bonnet 1B, also be furnished with corresponding to first grid G _1R, G _1G, G _1BPublic second grid G2.For instance, the structure of each filamentary cathode is such, promptly is the material carbonate that coating one deck can emitting electrons on a heating tungsten filament.Each filamentary cathode is collapsed tightly frame again between conducting bracket 6 and 7.Support 6 and 7 is distributed in the both sides of bonnet 1B respectively.One end of each filamentary cathode is fixed on the conducting bracket 6, and on another conducting bracket 7, be flexible pillar 7A, the other end of each filamentary cathode then is to be fixed on the 7A, according to above-mentioned structure, the problem that the filamentary cathode that causes owing to the temperature rising evenly extends, because of the compensation that elastic support 7A has been arranged has obtained solution, thereby above-mentioned filamentary cathode can not relax.First grid G _1R, G _1GAnd G _1BAll make half garden tubular, the cylinder of garden tube on above-mentioned cylinder, longitudinally is carved with many long and narrow groovings 8 by preset space length facing to each corresponding filamentary cathode again.The effect of long and narrow grooving 8 is can make the electronics that emits from filamentary cathode pass grooving to be transmitted.First grid G in the second grid correspondence _1R, G _1G, G _1BThat part ofly be made into the cylinder that has long and narrow grooving, the position of each grooving all faces the position of the long and narrow grooving of first grid.According to above-mentioned introduction, the long and narrow cylinder grooving 9R of second grid, the structure of 9G, 9B are as described below, the first grid G that promptly their cylinder is corresponding with each _1R, G _1G, G _1BBe to be in same garden in the heart.By above-mentioned structure, just can make the grooving 8 and 9 that passes first grid and second grid by filamentary cathode electrons emitted bundle as the crow flies, and scatter along the direction of grooving.On the other hand, long and narrow cylinder grooving is that part of not to be made into cylindrical shape if do on the second grid, but is made into flat shape (as shown in Figure 6).In this case, by the electron beam of cathode emission after passing second grid, though also be to scatter along the direction of grooving, but the formed curve of its scattering curves inwardly (shown in dotted line 30' among the figure).

On the other hand, around display segment (or display element) 2R, 2G and 2B, arranged the cage 10 that constitutes by electric conducting material.The effect of cage is maskable secondary emission electron 31 not only, in order to avoid it falls on the fluorescent material of adjacent display element, (seeing accompanying drawing 6), and can constitute dispersing lens.Above-mentioned secondary emission electron comprises because the secondary emission electron that is produced behind the electron beam hits first grid of cathode emission and second grid G1 and the G2.The effect of dispersing lens is to make by the electrons emitted bundle diffusion of each filamentary cathode K institute to come, and lives whole corresponding display segment 2 so that electron beam is topped.In addition, cage 10 is also as the electric supply installation that 10 kilovolts of high pressure are provided.From assembly structure, cage 10 is to stand between the header board 1A and sidewall 1C of glass envelope 1, and combines with the method for frit sintering.The more detailed diagram of cage as shown in Figure 7, cage 10 is made of three frameworks that are arranged side by side, each framework is round the display segment of correspondence.In the upper end of a pair of bogie side frame of framework, do the leg 11 of outside protrusion symmetrically, then do the anode pin 12 of introducing high pressure (anode voltage) in another upper end to bogie side frame.In addition, done outwardly-bent and whippy angle 13 in the both sides of cage 10.When cage 10 from top to bottom when glass envelope sidewall 1C packs into (as shown in Figure 8) leg 11 be close to the upper surface of sidewall 1C, thereby supporting whole isolated cover 10.And forniciform angle 13 near the medial surface of sidewall 1C so that cage 10 is in the center.The bogie side frame upper end of cage 10 has also been done aduncate lug 14 symmetrically, at each boss 15 is arranged all above the lug.After in cage is packed sidewall 1C into, again glass front plate 1A is placed above the sidewall 1C, and seal.The effect of convex 15 is to guarantee cage and carbon coating 3 and with metal back layer 5 excellent contact (as shown in Figure 9) is arranged.As a result, the required high pressure of display segment 2R, 2G and 2B is just introduced from anode pin 12 publicly.At assembling stage, the anode pin 12 of introducing high pressure is outwardly directed from the sealing-in part between header board 1A and the sidewall upper face 1C, and filamentary cathode K.The pin of first grid G1 and second grid G2 is outwardly directed from the sealing-in part between bonnet 1B and the sidewall 1C.The pin of negative electrode K, first grid G1 and second grid G2 is jointly drawn from a direction and has also been played the effect of supporting.For example, each first grid G _1R, G _1GAnd G _1BAll draw two pins, pin 16G1,17G1 and 18G1 as shown in accompanying drawing 4 in the both sides of glass envelope.There are four pin 16G2 to draw as for second grid G2 from four angles of bonnet 1B.The pin 20F of negative electrode from supported on both sides frame 6 and 7 left, draw to the right in groups.Negative electrode pin 20F links to each other with 7 with each side stand 6 publicly.Equally, corresponding to each first grid G1 and second grid G2, corresponding pin is connected also publicly.

By means of glass burn-back material 22(as shown in Figure 9), header board 1A, sidewall 1C and bonnet 1B reciprocally are packaged into one and have just formed glass envelope 1.There is an exhaust to cut hole 21 on the bonnet 1B, also seals with glass burn-back material.

Begin to narrate the operation principle of display unit now with said structure.Anode voltage (i.e. 10 kilovolts high pressure) adds to red, green and display segment 2R, 2G and 2B blue look by anode pin 12.The voltage that adds to first grid is 0 to 30 volt voltage, and the voltage that adds to second grid is 300 volts.The consumed power of every filamentary cathode KR, KG and KB is approximately 60 to 70 milliwatts.Press said structure, the service voltage of negative electrode and second grid G2 is constant, and the service voltage of first grid G1 is a variable, so that optionally control the opening and closing of each display segment.More particularly, when the service voltage of first grid is 0 volt, be cut off by the electron beam of cathode emission, thereby its corresponding display segment is not luminous.And when the supply power voltage of first grid G1 is 30 volts, pass first grid G1 by the electron beam of cathode emission after, quickened by second grid G2 again, collide at last on the fluorescent material of corresponding display segment 2, so that it is luminous.At this moment, the fluorescent brightness of display dot is to control by the pulse duration (duration) that control adds to first grid G1 voltage (30 volts).In addition, as shown in Figure 6, expand because of the effect of cage 10 by the electron beam of cathode emission and to come, so the face of whole display segment 2 is all topped by electron beam institute.When the electron beam hits of cathode emission is on first grid and second grid, just collision place at two grids produces secondary electron 31, but the electronics of Secondary Emission is subjected to stopping of cage 10.So they can not collide on the adjacent display segment.According to said method, by selectively controlling the supply power voltage that adds to first grid, just make display segment 2R, 2G and 2B send stronger fluorescence selectively.

This fluorescence display unit 40, with regard to one generally, its structure has thin form.In addition, the pin (for example pin of the pin of negative electrode and first grid and second grid) of supplying with low-voltage is to draw from the limit of the bonnet of glass envelope 1, and the anode pin 12 of high-pressure side then is to draw from the preceding utmost point 1A end of glass envelope 1.Because high voltage pin and low-voltage pin are drawn from both sides respectively, thereby just avoided the danger that may cause between interdischarge interval or wiring, just guaranteed that so also display unit can provide stable fluorescence to show.

In addition, owing to introduced anode high voltage to being centered around each display segment 2 cage 10 on every side, cage 10 has just been formed one group of dispersing lens.Therefore, even just the shape of first grid G1 is a cylinder bending, and second grid G2 is plane (as shown in Figure 6), be still laterally expansion by negative electrode K electrons emitted bundle and come (along the direction of grooving), and the topped firmly whole fluorescent surface of display segment 2.Simultaneously, also stopped because of the secondary electron that collision produces, so isolated adjacent display segment can be because of not luminous by the excitation of the electron institute of Secondary Emission by cage 10 by first grid and second grid.

Under the situation that colour shows the situation of 9300 ° of K white maps (for example), the mixing ratio of fluorescence is: be green glow for blue streak, about 13% for ruddiness and about 80% about 7%.When using filamentary cathode as the situation of electron emission source, in many application occasions,, the filamentary cathode that is employed gives fixed working life for being had, and their working temperature has certain limited field.Thereby the problem that the fluorescent intensity that green fluorescence negative electrode (below be called the shade of a tree utmost point) is produced will be higher than other the fluorescent intensity that negative electrode produced can solve by the number that increases the shade of a tree utmost point.For example: can use two shade of a tree utmost point K _G, and only use a red negative electrode K _RWith a blue negative electrode K _BAs a result, the total electron amount that produces green fluorescence is more than the electron amount that produces red fluorescence and Lan Se fluorescence, causes the colour that might influence demonstration.Self-evident, also can adopt a plurality of red negative electrodes and blue negative electrode, this also is effective for the working life that prolongs them.So by increasing the method for negative electrode number, but the number that the shade of a tree utmost point increases is more than the number that other negative electrode increases, this is to the briliancy of strengthening green fluorescence and be that the white light balance of obtaining is desirable method.Therefore, applied negative electrode can not form the overload phenomenon, and the life-span of fluorescence display unit just can be extended.In fact, two shade of a tree utmost points spacing of arranging each other is 0.8 to 1 millimeter.As for two shade of a tree utmost point electrons emitted total amounts, because electron scattering effect although the emitting electrons recruitment is not one times of single shade of a tree utmost point emitting electrons quantity, can give the recruitment of phase 70% to 80%.Another way, the briliancy of green fluorescence also can be made to such an extent that the bigger method of ratio area red and blue look fluorescence coating strengthens by the area that makes the green fluorescence layer.

Because filamentary cathode is to work in the temperature limited region of defined, burnt red for fear of oxide coated cathode exactly, the capacity value of oxide coated cathode be decided to be its maximum allow capacity value 1/10th to a few tenths of, therefore the electron amount of every filamentary cathode is less.A solution to the problems described above can strengthen the surface area of oxide fully, as spirality ground coiling tungsten filament.But, with regard to a long spiral, the defect that negative electrode is loose or vibrate most likely takes place.Consider this point, the structure shown in accompanying drawing 10 and 11 is adopted in suggestion.

In the example of suggestion, heart line 35 is made by exotic material, for example with tungsten or the such material of molybdenum.The surface of heart line scribbles picture AL ₂O ₃Such insulating material 36.Be used as the outside of the tungsten filament helix shape ground of heater, then with electronic emission material 38(such as carbonate compound around heart line) be bonded in the helicoid outside with spraying or electric plating method, direct-heated cathode has just been made.With spot welding or other suitable method of attachment, an end of heart line 35 is fixed on the support 6, the other end then is fixed on the elastic support 7A of support 7.Heart line 35 is to be anchored between support 6 and the elastic support 7A stretchingly.And spiral tungsten filament also is to be fixed between second support 6' of support 6 and opposite side with spot welding or other suitable method of attachment.

Thereby by above-mentioned version, promptly the skin of negative electrode scribbles insulating material 36, the spirality ground outside around heart line 35.Heart line 35 is tightened up by means of the elastic force of elastic support, can be excluded such as the short circuit problem between adjacent two spirals in helicoid inside and the thermal deformation problem of spiral like this.In addition, oxide surface is long-pending have been increased fully, and because the temperature difference of negative electrode two ends and its middle body has diminished, the uniform temperature distribution on the negative electrode has just broadened.As a result, the electron number by cathode emission has increased.As a complete unit, the maximum heating current that allows of each negative electrode just may increase.Curve I shown in the accompanying drawing 11 has represented temperature distribution history.

Like this, the fluorescence display unit just has been made into.In this example, cage has been installed to the location around a plurality of display segments, since on the cage with high pressure be exactly the same high pressure that adds on the display segment, thereby formed dispersing lens around the display segment, just expand to the whole fluorescent surface of each display segment or display element thereby the demonstration that just might obtain high brightness by the electron beam of cathode emission along horizontal direction.In addition, the effect of cage also can barrier by the secondary electron that produces because of collision on control grid or the accelerating electrode, be unlikely and fall adjacently by on the fluorescence coating of the display segment of barrier, thereby can realize that stable fluorescence shows.

When image display apparatus is to utilize above-mentioned fluorescence display unit to constitute, just need to adopt following assembly method.

The many fluorescence display unit 40(for example number of display unit are: the 6(row) * and 4(is capable)=24) will be assembled in the display unit box 41, to constitute parts as shown in figure 12.In the process that so many display units is assembled in the display unit box 41, display unit 40 is fixed on the part cartridge 41 by resin glue or sticking the applying of similar adhesive.Yet, since the anode high voltage of display unit 40 up to 10 kilovolts about.If so install not firmly, when connecting high voltage source or using liquid cleaning agent when removing the foul of spot on the display unit adhesive surface and so on, display unit 40 will split away off from adhesive surface.When service condition changes, also can cause this class fault equally.Therefore display unit must be packed on the display unit box securely.For reaching this purpose, each display unit should be made by following shape, and the header board 1A that is exactly glass envelope 1 should be protruding outside sidewall 1C.In this example, header board 1A can stretch out in outside the sidewall from four sides as accompanying drawing 13A, perhaps can be as accompanying drawing 13A outside both sides stretch out in sidewall.From another point of view, display unit box 41 should be made into as shown in Figure 14, being exactly that should make in a plurality of these illustrated devices of fenestra 43(on the position of front panel 42 corresponding to fixing display unit 40 of display unit box 41 is 24) back side at each fenestra edge done step 44, and the size of step should match with the marginal portion of each display unit 40 header board.Display unit 40 is from the installing previously of front panel, so that header board 1A is pro towards fenestra 43, and then uses the back side that is coated in front panel such as the cement of resin glue one class, and display unit is fixed.In this example, because header board 1A has protruding part 50, it is sandwiched between the front panel of cement 45 and display unit box 41, and whole like this display unit just is fixed on the display unit box securely.If necessary, can be as shown in accompanying drawing 15 and 16, when assembling, increase by a stator 53 again, this stator can rotate so that header board extension 50 is clipped between the front panel of it and display unit box 41 around axle 52.And then with the cement of resin glue one class they are sticked together, be fixed more firmly to guarantee display unit.Owing to will send very strong light on display unit, the temperature that applies the fluorescence coating side at header board 1A is easy to rise very highly, therefore is necessary to take cooling provision to make its cooling.For example use liquid coolant.In order to realize this measure, when being packed in each display unit on the display unit box, packing ring 54(such as silicone rubber gasket) should be sandwiched between the step part 44 and display unit header board 1A of front panel 52 of display unit box 41 transparent panel 55 that the dress lastblock is made by the transparent material of polycarbonate one class on them again.So just can in by transparent panel 55, header board 1A and display unit box fenestra 43 formed spaces, inject cooling fluid 56.In this example, on the front panel 42 of display unit box 41, do the cooling fluid that is communicated with fenestra 43 and inject groove 57.If, also can adopt fan that display unit is carried out air cooling without the cooling fluid cooling.

After the assembling of finishing above-mentioned display unit, just many above-mentioned display units are arranged by the X-Y matrix-style, for example by 7(row) * 5(is capable)=35 mode arranges to form a display module, 5 groups of display modules laterally arranged, to form a submodule again.And then many above-mentioned submodules are combined by the X-Y dot matrix way, for example by the 9(row) * 4(is capable)=36 mode makes up.Submodule after more some being made up like this always is fitted together, and a huge vision charactron has for example just been made successfully 25 meters (row) * 40 meter (OK).In this example, the sum of display unit is:

36×5×35×24＝151，200

The sum of display segment then is three times of display unit, thereby is approximately 450000

Figure 17 A and Figure 17 B are respectively front view that has huge image display apparatus building and the cross section views after building up.For example this building that has image display apparatus is of a size of 42 meters high, 47 meters wide.The top that has the image apparatus building is image display portion, and its branch builds up for nine layers, and the height of each layer is 2.688 meters.Each layer have 4 submodules in a lateral direction.Have the central control room that stage, lobby and the operation, control chart image display device and the stage facility that carry out performing active and use are used in the bottom of this building.

By above-mentioned approach, image display apparatus has just built up.In this example, because the process of assembling is: before this 24 display units were consisted of a display unit, and then several display units always are fitted together constitute a complete image display apparatus, thereby display unit just becomes and is convenient to operation and maintenance, also is convenient to install.The shape of the display unit of (be above-mentioned example in) made is that height and width all are 40 centimetres square in this example.

Should point out in passing, concerning above-mentioned this image display apparatus, when the shows signal corresponding to each display unit will be transmitted, can not concurrently shows signal be sent to about 450000 visual displaying monomers (or being called pixel) simultaneously.So the transmission of signal can only realize with the mode of scanning, yet in this example, display device adopts display unit to be assembled, if use the mode of known line program scanning, wiring workload between the adjacent display unit of then transversely arranged each is very big, and therefore the installation of whole image display apparatus just becomes very complicated.

In addition, because display unit is a sort of huge image display apparatus as previously described, if the transmission of signal is carried out according to the analog signal load mode.Visual display error such as accurate mistake when just being easy to cause visual colour contamination.Thereby can consider to transmit signal by the form of digital signal.If yet being used as signal transmssion line with common such flat cable, the highest signal velocity can be above about 300 kilo hertzs.Consider that from another point of view the time of transmitting the view picture picture intelligence should be shorter than a thirtieth second again.

Yet, with regard to above-mentioned display unit, if display unit normally be installed in outdoor like this, the suitable display brightness of device is different with the difference of application conditions: for example be use at night or use by day, be fine, be the cloudy day, or the weather condition on rainy day under use.For example in background light very strong fine day under the application conditions, suitable display brightness has been adjusted, but just becomes too strong at the display brightness that mixed up night, so that the image that is shown can not be watched satisfactorily.Therefore the control of the briliancy of display unit should realize by aforesaid method, and that then installs display brightness differentially also dies down along with background light and reduce, and so just can not expectation obtain high-quality image demonstration.

An object of the present invention is to provide a kind of video display system of being convenient to transmit signal.

Another object of the present invention is that a kind of video display devices will be provided, and image demonstration briliancy can enough easier methods be controlled in this display unit.

Narrate from one aspect of the present invention, video display system provided by the present invention should comprise:

One has many display units of arranging by the X-Y matrix-style;

A video signal source that is used to provide digital video signal;

A pulse-width modulator that is connected with described video signal source, this modulator can provide the pulse-modulated signal corresponding to the different in width of the different brightness degrees of described digital video signal, a counter and a clock-signal generator are arranged in the described pulse-width modulator, and the data-signal that counter is added with is exactly that the clock signal of digital video signal counter is then from described clock-signal generator.

Also have a conveyer that is connected with described pulse-width modulator, this conveyer provides pulse width modulating signal so that demonstrate image on display unit for described display unit; Apparatus of the present invention are characterised in that:

A control device that is connected with described clock-signal generator is arranged, and this control device can be controlled the clock signal frequency of delivering to counter, thereby also can control the brightness that image shows on the display unit.

Other purposes of the present invention, characteristics and superiority thereof will be obvious by the narration below in conjunction with accompanying drawing.In all accompanying drawings, adopt identical label with parts for components identical.In the accompanying drawing.

Fig. 1 is the front view of the applied fluorescence display unit of the present invention;

Fig. 2 is the profile after the fluorescence display unit cuts off along the A-A line among Fig. 1;

Fig. 3 is the profile after the fluorescence display unit cuts off along the B-B line among Fig. 1;

Fig. 4 is the perspective view after partly the cutting of fluorescence display unit among Fig. 1;

Fig. 5 is the amplification profile of display segment;

Fig. 6 is the profile of explanation cage operation principle;

Fig. 7 is the perspective view of cage;

Fig. 8 is the plane graph that places the cage of capsule one side;

Fig. 9 is the profile of display segment and part cage;

Figure 10 is the profile of the another kind of filamentary cathode of expression;

Figure 11 is a filamentary cathode shown in Figure 10 perspective view at assembling stage;

Figure 12 is by view before the display unit of a plurality of display unit assembling usefulness;

Figure 13 A and Figure 13 B represent the perspective view of other form display units respectively;

Figure 14 is the profile after the display unit among Figure 12 cuts off along the C-C line;

Figure 15 is the profile of the another kind of assemble method of expression display unit;

Figure 16 is the bottom view of display unit assemble method shown in Figure 15;

Figure 17 A and Figure 17 B are respectively the front view and the profile that have * type display unit building;

Figure 18 is the square principle figure of video signal display system provided by the present invention;

Figure 19 and Figure 21 are respectively the schematic diagram of expression signal feed system provided by the present invention;

Figure 20 A to Figure 20 G is respectively the signal waveforms of relative section in the video display system provided by the present invention;

Figure 22 is the principle schematic of the applied pulse-width modulation exciting circuit of the present invention;

Figure 23 is the frame principle figure of the side circuit of the applied timing signal device of the present invention.

We do one to the present invention and describe with reference to accompanying drawing now.

Figure 18 is the systematic square frame schematic diagram, is used for illustrating a concrete instance of video display system proposed by the invention.In this example, vision signal can be selected the input equipment of wherein arbitrary input equipment as vision signal by selector switch 104 from input equipments such as television camera 101, video tape recorder (VTR) 102 or tuners 103.The vision signal that is provided by above-mentioned input equipment all belongs to composite video signal, for example the synthetic signal of looking of balanced quadrature modulation (NTSC) system.Vision signal by selector switch 104 inputs is at first delivered to decoder 105, and this decoder is decoded the composite video signal of sending here, can get the signal component of red, green and three kinds of colors of blue look thus.The signal component of these three kinds of colors is connected to each self-corresponding analog to digital converter (A/D converter) 106R, 106G and 106B again respectively, and in described A/D converter, the signal component of three kinds of colors is converted into 8 parallel digital signal respectively.

Described parallel digital signal is alternately delivered to memory sets 171(171R, 171G, 171B) and memory sets 172(172R, 172G, 172B), each memory all has a field pattern and resembles the required memory capacity of demonstration, each memory in the above-mentioned memory sets 171 and 172 also all becomes a scan converter, and each scan converter can convert 5 row input signals to 4 line output signals.In addition, in the sweep signal of the every field pattern elephant after conversion, choose the horizontal line signal of 189 behavior displayed image again, again the described horizontal line signal of every triplex row is made up and obtain one group of scan converter output signal, concerning showing that every field pattern resembles, always have 63 groups of (* 8 parallel-by-bit) scan converter output signals so.

In this example, the order of scan converter output signal is specific, Here it is after the process that transmits signal to a display unit (as previously mentioned) is finished, and the process that transmits signal to next (adjacent in other words conj.or perhaps) display unit just begins to carry out.Accompanying drawing 19 has provided two adjacent display unit U ₁And U ₂The schematic diagram of signal transport process, each blockage is represented respective display unit among the figure, a map in the time a certain section numerical data of corresponding a certain display unit provide in turn by a memory, the order of sending data is by that display unit of numerical order on the left side U represented among the figure ₁In after corresponding three horizontal line 201 to 204,205 to 208 and 209 to 212 segment data send in the memory fully, send again corresponding to the right that display unit U ₂Triplex row 213 to 216,217 to 220 and 221 to 224 segment data.Memory is sent the required segment data of that triplex row display unit in the adjacent display unit in the right one by one.The required segment data of each row display unit that is indicated with upper right left-falling stroke " ' " in the accompanying drawing 19 is provided by another memory in the time in next interleaved map.

These segment datas are provided by each self-corresponding memory 171 or 172 simultaneously respectively.The process of sending above-mentioned segment data from memory is such, is to send simultaneously corresponding to 63 groups of data of every triplex row.The data of being sent are connected to data selector 108.Segment data red, green and blue look is chosen from the data that memory is sent here selector 108 pointwises ground in the time at every reflection, so that form 63 groups of new (* 8 parallel-by-bit) data-signals.Selected memory can not carry out write operation simultaneously.Multiplexer 109 will become corresponding serial data signal from 8 parallel-by-bit conversion of signals of selector 108.Optical signal converter 110 will convert corresponding light signal again from the serial data signal of multiplexer to.

The pairing 63 groups of optical signal datas of every triplex row horizontal signal by optical cable 301,302 ... 363 deliver to transversely arranged parts group circuit 401,402 respectively ... 463 core, each parts group circuit is represented whole display units transversely arranged in the display unit.

For example topmost one arrange in the pairing cross member group of the display unit circuit 401 in display unit, from light signal feed-in one optical-electrical converter 111 of optical cable 301, this optical-electrical converter converts this signal to the corresponding signal of telecommunication again.Data-signal after this conversion is fed in the demultiplexer 112 and goes, and separator converts the serial data signal of sending here to 8 parallel data signal again.This parallel data signal is through data/address bus 113 simultaneously (for example) and 100 transversely arranged component circuitry 114 concurrently ₁, 114 ₂... 114 ₁₀₀Parallel linking to each other.

Deliver to sync separator 115 simultaneously from the parallel data signal of optical-electrical converter 111 and in separator, form required synchronizing signal by the effect of giving fixed circuit such as survey view pattern generator.This synchronizing signal is connected to timing signal and forms circuit 116.This timing signal forms circuit can form following timing signal respectively: frame pulse signal FP, this signal are every paraphase once (shown in accompanying drawing 20A); Parts clock signal UCK, this signal during the half period of described frame pulse signal (1) have 255 weeks (shown in accompanying drawing 20B); Pixel clock signal ECK, in the cycle of per two parts clock signal UCK, form 38 cycles (shown in accompanying drawing 20C) altogether, and initial pulse Ssup, the pulse duration of this initial pulse is the width of a pixel clock signal, the latter forms (shown in accompanying drawing 20D) constantly in the frame pulse signal paraphase, above-mentioned frame pulse signal, parts clock signal, pixel clock signal and foregoing data-signal all are to deliver to corresponding components circuit 114 separately concurrently by data/address bus 113 ₁, 114 ₂... 114 ₁₀₀) and initial pulse is to deliver to first component circuitry 114 individually ₁.

63 cross member group circuit (401,402 ... the course of work of each the parts group circuit 463) all is identical.

The formation of the signaling conversion circuit of the arbitrary component circuitry in the cross member group circuit as shown in Figure 21.In accompanying drawing 21,121 represent a shift register that has 38 grades.In this example, the pixel clock signal ECK that forms circuit 116 from timing signal adds to the input end of clock of shift register 121 through data/address bus 113, and initial pulse Ssup adds to its data input pin.Like this, under the effect of pixel clock signal, corresponding to different shift clock signals, the shift register adjoining land is sent shift signal S ₁, S ₂... S ₁₈) shown in accompanying drawing 20E).S in these signals ₁To S ₃₆Be connected to respectively each self-corresponding display unit 201 to 212 pixel circuit 201R, 201G, 201B, 202R, 202G, 202B ... to 212R, 212G, 212B and corresponding display unit 201 ' to 212 ' pixel circuit 201'R, 201'G, 201'B, 202'R, 202'G, 202'B ... 212'R, 212'G, 212'B.In accompanying drawing 21, represent these circuit to have identical circuit structure with the represented square frame of dot-dash center line.

Data-signal from data/address bus 113 is connected to all pixel circuit 210R to 212'B(concurrently shown in accompanying drawing 20F).Frame pulse signal FP delivers to 201R to 212B, and the signal of frame pulse signal after inverter 122 is anti-phase delivered to 201'R to 212'B.

Shift signal S from shift register 121 ₃₈Be sent to d type flip flop 123, this d type flip flop forms an initial pulse Ssup'(again shown in accompanying drawing 20G), this initial pulse Ssup' is connected to next adjacent component circuitry.

The formation that is used to encourage the luminous signal circuit of each pixel as shown in Figure 22.In accompanying drawing 22, one 8 latch circuit of 131 expressions, this latch circuit is added with data-signal from data/address bus 113 at its data input pin.AND circuit 132 has two inputs, an input incoming frame pulse signal FP or its inversion signal.Another input and S ₁To S ₃₆In a certain shift signal link to each other.The output signal of AND circuit 132 then adds to the control end of latch circuit 131.8 reciprocal counters of in the accompanying drawing 22 133 expression.The data of this counter are given and are put end and link to each other with the output of latch circuit 131, the counter input be added with input pulse (signal S from shift register 121 ₃₈) and the input end of clock of counter is added with the parts clock signal UCK from data/address bus 113.When counter 133 was in state beyond complete zero, it produced output signal all the time.This output signal is connected to the first grid G of aforementioned each display unit ₁The output signal of counter 133 adds to it after inverter 134 is anti-phase counting stops end.

Therefore in each pixel circuit of each component circuitry, at signal S ₁To S ₃₆Particular moment, the latch circuit 131 of corresponding unit pins and keeps data-signal from data/address bus 113, maintained data-signal is put data at signal S as giving of counter 133 ₃₈The time engrave and be selected into counter 133.Then 133 pairs of reciprocal counters this give put data begin reciprocal till counter is in all-zero state, so the output of counter 133 just obtain one with the corresponding pulse width modulating signal of each data-signal.In this example, counter 133 is along with parts clock signal UCK is falling counting to giving the data of putting.Because the parts clock signal has 255 cycles in time field duration, so when data-signal was maximum, corresponding pixel showed in a field time continuously, and when data-signal was minimum value, corresponding pixel did not show.The demonstration briliancy of pixel can be divided into 256 grades like this.The first grid of each display unit pixel can be encouraged by described pulse width modulating signal PWM.

In addition, at signal S ₃₈Formation constantly, the initial pulse signal of next adjacent component circuitry has produced simultaneously.100 one of transversely arranged component circuitry are followed the process that a ground is repeating above-mentioned excitation display element.The time of data latching operation is two cycles of parts clock signal UCK in each component circuitry, and 100 transversely arranged component circuitry are repeatedly finished the cycle of the time of aforesaid operations with regard to 200 parts clock signal UCK of needs so.Like this, also 55 UCK cycles of remainder just can be used to transmit such as special control signals such as synchronizing signals in the time at a reflection.

Because the frame pulse signal FP of next reflection is the inversion signal of a last reflection frame pulse signal, the process of motivation of interleaved another part pixel is identical with the process of motivation noted earlier.At this time, give and put pulse and deliver to once more in the pixel circuit that produces a last reflection and go, thus continuous two reflection in the time each pixel repeat twice ground and finish identical demonstration.

How to have narrated on 100 transversely arranged display units parallel simultaneously the carrying out of process of displayed image above, the demonstration of view picture image has also just been finished thus.

In the described display unit, the actual composition of timing signal formation circuit 116 as shown in Figure 23.Reference oscillator 501 is crystal oscillators in accompanying drawing 23, its frequency of oscillation is 4,646549 megahertzes, this oscillator signal are sent in the frequency divider 502 to 505 of two divided-frequency of 4 polyphones and remove frequency division, and the signal frequency of being sent by frequency divider 505 is approximately 300 kilo hertzs and be added to latch circuit 506.Be connected to latch circuit 506 by switch 507 through the frequency divider 508 of 19 frequency divisions and the frequency divider 509 of two divided-frequency by reference oscillator 501 and frequency divider 502 to 504 output signal separately, and the output signal of frequency divider 505 is connected to latch circuit 506 through the frequency divider 511 of frequency divider 510,255 frequency divisions of 19 frequency divisions and the frequency divider 512 of two divided-frequency.Be connected to from the synchronizing signal of sync separator 115 and go in the latch circuit 506 to realize synchronously.

Form in the circuit 116 at above-mentioned timing signal, the pixel clock signal (ECK) that is approximately 300 kilo hertzs is from frequency divider 505, and this pixel clock signal is connected to latch circuit 506 again.In 506, deliver to terminals 513 again synchronously with synchronizing signal.The cycle of frame pulse signal FP is 255 * 38 times from the pixel clock signal cycle of frequency divider 512.This frame pulse signal and synchronizing signal are delivered to terminals 515 synchronously.

When the travelling contact of change over switch 507 was linked that contact, the top, the cycle of frequency divider 509 formed parts clock signals (UCK) was 19 times of pixel clock signal cycle.This parts clock signal is delivered to terminals 514 with synchronizing signal synchronously in latch circuit 506.When changed downwards the position of the travelling contact of moving point type change over switch 507, the frequency of parts clock signal also and then became the twice, four times and eight of frequency divider 509 pairing parts clock signal frequencies.

When these clock signals are connected to the clock signal input terminal of aforesaid reciprocal counter 133, along with the width of increase pulse width modulation (PWM) signal of frequency also along with becoming 1/2,1/4 and 1/8 of former pwm signal width.

Therefore, the briliancy that image shows is controlled, and promptly briliancy can correspondingly become 1/2,1/4 and 1/8 of former briliancy.At this moment, the luminance level scope of pulse width modulating signal control still has the 0-255 level, and this might be avoided reducing owing to the briliancy grade that briliancy control causes.

Thereby demonstrate the huge image of 25 meters (row) * 40 meter (OK).Press the graphical presentation system of said structure, since map data be a display unit then the mode of a display unit transmit, the transmission of the visualization data of next display unit, to after finishing, a last display unit Image Data transport process just begin to carry out, so visual procedure for displaying is undertaken by parts ground.As a result, the connection between the adjacent component circuit only needs a line just can send the initial pulse signal Ssup of a last component circuitry to next component circuitry, so the connection between the display unit becomes very simple.The transmission of the data-signal from bus to each parts etc. can adopt the multiple-contact connector to realize.Thereby after display unit interconnected, if changing the work that connects between them has again become simply, the assembling of display device and maintenance work were very easy too.For example, be out of order, only need have changed that out of order display unit just with a good display unit as a display unit.When changing, because the quantity of electrical connecting wires seldom, so can realize quickly and easily more changing jobs.And because line is less, so can reduce equipment fault obstructed because of contact or that loose contact causes.

Be pointed out that also following method can be used as the emergency measures of maintenance of equipment, inserting one exactly between the input of fault display unit initial pulse and output, to count to 38 counter just much of that, just can take the display unit of fault then away.Taked above-mentioned emergency measures, can't produce harmful effect other display unit.In addition, when need be check the time to operation of certain display unit itself, because the formation of various signals and transmit and all realize in components interior, so the maintenance of a display unit is also become very easy.

Because visual data presented is to send each transversely arranged display unit concurrently to.So the transmission of data can be carried out on low speed ground.That is to say that the speed of data transmission becomes in the above-described embodiments:

60 * 255 * 38/2=290,7(kilohertz)

The maximum that this transfer rate is lower than flat cable (data/address bus) allows transfer rate (300KHz), transmits data so just may use conventional flat cable.

The transmission of the map data of above-mentioned image display apparatus is undertaken by following mode, be exactly to transmit two interleaved data-signals in the frame reflection time, thereby pictorial data only needs to rewrite once on each pixel circuit in the frame reflection time.Yet repeat to show once in visual two vertical intervals that are presented in succession.And image shows that repetition rate is 60 hertz, so can get rid of the scintillation that image shows.

In addition, in above-mentioned display unit, by changing the frequency of clock pulse in the pulse width modulation circuit, just can control the brightness that image shows at an easy rate, thereby no matter be this display unit of application under which type of weather condition, the demonstration briliancy that always can obtain to suit, thus can prevent to show the minimizing of the progression of briliancy.

According to said apparatus of the present invention, the transmission of signal has become simply, and the briliancy control that image shows also realizes easily.

Above description is based on to be carried out on the basis to a most preferred embodiment proposed by the invention.But what show that face easily sees is that an one of skill in the art may make many modifications and changes and not break away from the spirit or scope of novel concept proposed by the invention the present invention, so scope of the present invention only should decide by the accompanying Claim book.

Claims (11)

1, video display system it have:

A display unit that comprises many display units of arranging according to the X-Y matrix form;

A video signal source that is used to provide digital video signal;

A pulse-width modulator that links to each other with described video signal source, the pulse width modulating signal that this pulse-width modulator provided is corresponding with the brightness degree of described digital video signal, described pulse-width modulator comprises a counter and a clock-signal generator, counter utilizes the data-signal of described digital video signal as it, and the clock signal of counter is provided by clock-signal generator;

With a conveyer that links to each other with described pulse-width modulator, this conveyer sends described pulse width modulating signal to described display unit so that displayed image on this display unit.

The invention is characterized in:

Have a control device to be connected with described clock-signal generator, this control device can change the frequency of the clock signal that offers counter so that can be controlled at the brightness of displayed image on the display unit.

2, by the described video display system of claim 1, wherein said control device comprises the frequency divider and the switching device of many polyphones, the polyphone frequency divider be link to each other with clock signal and switching device is to be used to select the frequency division output of multistage frequency divider and this frequency division exported offer described counter as clock signal.

3, by the described video display system of claim 1, wherein said counter is falling to count to clock signal.

4, by the described video display system of claim 3, wherein said 〈 ﹠﹠〉degree modulator also comprise locking devicen and conveyer, locking devicen is used to pin the digital video signal from described video signal source, and conveyer is used for being sent to described counter by the vision signal of being locked to give as it and put data.

5, by the described video display system of claim 1, wherein said frequency is looked signal source an analog to digital conversion circuit, and this analog to digital conversion circuit is used for the analog video signal of input is converted to digital video signal.

Images