CN85200882U - Large screen projection display arrangement with liquid crystal device - Google Patents

Abstract

The utility model belongs to the technical field of liquid crystal display. The device comprises two systems such as an optical system composed of a projector and a screen, and a circuit system including a liquid crystal display element. The utility model is characterized in that the driving electric information to enable the liquid crystal display element to generate changes originates from a computer, an electronic watch, an electronic clock or a circuit capable of generating the character information. Through justifying the image distance of the projector object lens or displacing an objective lens with different focal-length, the displaying area of the large screen projection can be changed. If a single color polarizing film is changeably equipped in the liquid crystal display element of the device, the single color large area display can be realized. Or a liquid crystal display of which the pixel is composed of three primary colors is positioned in the device, and the color displaying in large area can be realized.

Description

Liquid crystal large screen projection display device

One, technical field under the utility model: liquid crystal display,

Two, relevant prior art

Existing display device such as bulb, fluorescence, electroluminescence, plasma, cathode-ray tube (CRT), light emitting diode and electromagnetic and mechanical turnover panel.Above-mentioned device all belongs to the active illuminating device except that the electromagnetic and mechanical turnover panel, therefore must consume enough electric energy for device itself is luminous.And liquid crystal device is passive luminescent device, and is not luminous because of itself, must consume enough energy so do not resemble above-mentioned active illuminating device, only consumes extremely small electric energy when driving liquid crystal device generation electrooptical effect.For example the driving voltage of meander configuration liquid crystal device is 3～6 volts, only about 5～10 microwatts of the power consumption of every square centimeter of display area, and the utmost point is suitable for integrated circuit and matches.

Desire realizes the demonstration of large tracts of land (for example more than a square metre), and as adopting the active illuminating device, because power consumption is bigger, thereby driving circuit is expensive bigger.Form the large display screen that area is about a square metre by 30 electroluminescent devices during for example China just actively manufactures experimently, the equipment expense of one cover driving circuit (can drive two each large display screens of one square metre) only, about seven to 80,000 yuan.The big form character display system of liquid crystal of four units such as Tsing-Hua University cooperation research and development success (seeing in September, 1984 for details) in the big form character display system of the Nn-Ch of Held in Beijing storage type liquid crystal evaluation meeting data, be by totally 138 of the individual devices that varies in size, form the about 3 square metres large display screen of area.This system opened evaluation meeting since development in 1978 in 1984.

The common information display that U.S.'s overseas call telegram element group's microwave and optical electronic device Xi Feierde company (TTT Components Grvoup Microwave and Opto-Electronics Westfield Mill) produced in 1981 is made up of 24 single liquid crystal devices, total about 0.14m of display area ²(1.7 meters in length * high 0.08 meter) is as the information display of boarding lounge.

Chengdu Inst. of Computer Application, Chinese Academy of Sciences is display screen input station, the Chengdu waiting room utilization with railway station Tourist Information disposal system in October, 1984.This screen is formed matrix display panel with the quantity pixel, the about 0.7m of its effective display area by 1596 electromagnetic and mechanical black and white turnover panels ²(1.2 meters * 0.6 meter) can show the ordinal number of train number, name of station, the moment and platform.About 10,000 yuan altogether of equipment of each display screen (comprising driving circuit) and processing charges.12 ticket barriers are provided with 12 display screens.

Writing information light is invested photoconductive liquid crystal light valve abroad, cross light valve projection to screen (A.D.Jacobson, Soc with the stronger transmittance of reading again, Ixform, Display, Symp.San Francisco 1972.70), realize the liquid crystal large screen display.This is to convert the electrical signal to light signal by cathode ray tube (CRT), again light signal is invested photoconductive layer and is converted to electric signal, and this electric signal produces on liquid crystal that electrooptical effect realize to show.

Also making writing information light with laser abroad invests by nematic phase and courage

The small size light valve that the phase liquid crystal is made with the stronger light transmission light valve of reading, is read the information (H.Mclchior etc.Appl.Phys.Lett.21(8) that has write, P.392, and 1972).This is the intensity of transferring infrared laser beam by electric signal, again laser beam is invested liquid crystal, and the realization of generation thermo-optic effect shows on liquid crystal.

Liquid crystal large area display or electroluminescence large area display must be made up of some single small size liquid crystal devices or some single small size electroluminescent devices.Because it is in full accord that the device production process conditions are difficult to guarantee, the result makes each single small size liquid crystal device or electroluminescent device performance parameter also just be difficult to unanimity, when carrying out the large tracts of land demonstration, is prone to each partly deep or light differing.The large area display that electromagnetic and mechanical black and white turnover panel is formed, because when showing is black and white two states, though there is not the deep or light phenomenon that differs, there also have the only a few pixel to show to be undesired, promptly should display white show black on the contrary, display white on the contrary in the time that black should being shown.

The large area display of more than giving an example is to form with some single electroluminescent devices, some single liquid crystal devices, some single magnetic turnover panels respectively, cause the large area display cost to be difficult to reduce, simultaneously again because number of devices is many, power consumption increases, and makes the cost of driving circuit be difficult to reduce again.

Though more than two kinds of liquid crystal light valves belong to single small-area display part, be by several conversions, more complicated is expensive, is used for showing that the image of high-resolution is more suitable, but only shows just uneconomical as character.

Three, the purpose of this utility model

In view of said method realizes that the large tracts of land demonstration is expensive bigger, information such as the character that event shows desire, chart, curve etc., with the electrical signal form small single small size liquid crystal device of power consumption that writes direct, make liquid crystal produce electrooptical effect, just read the information that shows on liquid crystal device, liquid crystal is crossed in light transmission that again will be stronger, amplifies through optics, be projected to screen, also can realize 1m ²Above large tracts of land shows.Certainly require the pixel shown on so single small size liquid crystal device should be suitable with the shown altogether pixel of the large-area liquid crystal device that some single liquid crystal devices are formed.The price of the former a single small size liquid crystal device is than the some liquid crystal devices in single of the latter, and is perhaps more expensive, but the broad area device of forming than some single liquid crystal devices considerably cheaper always; The former driving circuit is also than latter's considerably cheaper; The former only uses several liquid crystal devices with a liquid crystal device than the latter, and the reliability of complete machine is improved greatly.

Four, content of the present utility model

The synoptic diagram of experimental provision such as Fig. 1, this device is made up of optical system and Circuits System (Fig. 1 dotted line partly is Circuits System S, and its block diagram is plotted in Fig. 2 in addition).Liquid crystal display device LCD in the Circuits System places the film gate position of optical system.Optical system is: 1. for reflective mirror (can saturating infrared cold mirror to be advisable), 2. be light source, 3. be condenser, 4. be objective lens, 5. be projection screen; Also has fan (cooling usefulness does not mark) in Fig. 1; Bigger as light source power, the temperature that makes liquid crystal device should add an amount of heat-protecting glass during near its maximum operation (service) temperature between the light path of light source and liquid crystal device; When to the liquid crystal device air blast cooling when invalid, still liquid crystal device should be placed the insulation of cooling capable of circulation and transparent liquid medium; For preventing that ultraviolet ray from playing photochemical reaction to liquid crystal,, can between the light path of liquid crystal device and light source, add and filter ultraviolet optical filter (polaroid of the liquid crystal device that has has the effect of filtering ultraviolet) to prolong liquid crystal serviceable life.

The picture displayed area can be adjusted on the screen, distance is the image distance except that between common change objective lens and screen, also can allow image distance constant substantially, the focal length that only changes object lens promptly (can be with the object lens of different focal with the original object lens of object lens replacement of another kind of focal length, be contained on the garden dish, rotation garden dish can be easily between light path with the object lens embolus of a certain focal length and elephant) instrumentality distance again, make imaging clear, so just adjust the area of display frame on the screen easily, as long as make picture not have bigger distortion and the observation down of the enough prevailing circumstances of brightness.The large tracts of land that some individual devices are formed shows that its picture area can not be adjusted.

Projection screen can adopt front projection screen (being the reflection type projection screen) or bear projection screen (being transmissive projection screen) all can.Screen material has several, selects for use as required.

If desired, can in light path, insert an amount of catoptron, can change optical path direction just changed thing, object lens and resemble between relative position, to reduce the shared space of optical projection system.

The optical projector that adopts is actual to be exactly slide projector, performance on its nameplate is: the focal length of light source rated power 300W, camera lens is that 10CM, relative aperture are f/3.5, bulb rated voltage as light source is 120～125V, does following experiment in order to prolong the voltage that bulb life reality only adds 100～105V.

Start light source, make between optical projector camera lens and screen 2.9 meters of distances, projector's enlargement factor of calculating thus and measuring is about 30 times.Projector's film gate inside casing area of showing slides is 40 * 40cm ², when not letting alone what lantern slide or liquid crystal device in the sheet frame, the about 1.2 * 1.2m of projection light area on the screen ²Under no ambient light interference, record the about 250Lux of illumination on the screen, make transmission-type liquid crystal device LCD put into the film gate place, the electric signal that drives liquid crystal in the Circuits System is added on the liquid crystal device, even the ambient light on the screen is washed away down at 200-250Lux, it is big and clear to be projected in the character that shows on the giant-screen by liquid crystal device, and contrast is enough.Even this Projection Display is under the outdoor situation that sunlight arranged, indoor screen only otherwise over against sunlight, still can obtain comparatively satisfied viewing effect.Screen top and both sides are added a light shield, and the contrast of display degree will improve.If wish to obtain brighter and more large-area demonstration, can select or make by oneself the bigger projector of light source power for use, projector's film gate inside casing area will adapt to the liquid crystal device area.The slide projector of selecting cinema to use, light source power can reach about 1 kilowatt or higher, and should note the cooling of liquid crystal device this moment.In public down, watch for convenience of the masses and walk about, projector should be placed screen last the place ahead or on rear, dead astern.As the desire certain display area of maintenance and again with the distance shortening between projector and screen, can the focal length design of optical lens is short, for example the distance between projector and shielding is 1 meter, the horizontal width of display area also is 1 meter, an integral body can be made by projector and display screen, so that with its shift position.

Selected liquid crystal display device, matrix form is taked in arrangement of the transparency electrode of subtegulum on it, and some parallel banded transparency electrodes that promptly go up substrate are vertical mutually with some parallel banded transparency electrodes of subtegulum, and the point of crossing of upper/lower electrode is pixel.The liquid crystal device of a choosing distortion effect (also optional other effect) shows.Notice that the number of scanning lines that liquid crystal matrix shows should not be too much, otherwise generation cross effect, mostly LCD on the therefore present microcomputer is small size, its area shape is long and the wide bigger rectangle of ratio, and for example the PB-700 type Portable, personal microcomputer of NANHO board or CASIO has just adopted such rectangular matrix LCD.The larger area LCD is also arranged, the STM-PC portable minisize computing machine released of Canada in 1984 for example, its LCD is 250 * 80mm ², display element is 600 * 200 points.The PB-700 type portable minisize computing machine main performance of primary election and configuration are as follows:

Host CPU: HD61917A06, time clock 400CHz

Pay CPU:HD61917A07, time clock 200KHz

RAM:4KB(can add three every 4KB RAM, extends to 16KBRAM altogether)

ROM：25KB

Keyboard: small-sized, by standard ordering

LCD: LCD AC15351, matrix shows 160 * 32 points, effective display area 95 * 19mm ²(white and black displays)

Drawing printer: four looks (black, red, green, orchid), maximum 80 characters of every row, average 11 character per seconds, FA-10 type (band tapereader interface)

Miniature box-like magnetic tape station: CM-1

English words, numeral, chart such as Fig. 2 that the LCD of PB-700 microcomputer is shown; Curve such as Fig. 3 of showing; Game graph such as Fig. 4 of showing.

The configuration of this kind type has constituted a microcomputer system, and price (a complete set of 2700 yuan) is suitable.As only purchasing main frame, keyboard and LCD (altogether in one closes for a short time), estimated price is about below 2000 yuan.

Circuits System S among Fig. 1, the PB-700 microcomputer system with primary election is representative (also can select other microsystem that internal memory is bigger, the liquid crystal display device area is bigger certainly) herein, its Circuits System block diagram 5.The course of work of this experimental provision is: the distinct program of display text (Chinese character or other kind literal) chart, curve and animated graphs is finished in advance, in the random access memory (RAM) (RAM) by keyboard input main frame, deposited in the program of internal memory RAM, also can send into external memory---note on the tape in the miniature box-like magnetic tape station (CM-1), so that the program that writes down on the tape is called in RAM again when needing.Select the P of keypad ₀～P ₉(0～9 program area) key has also just been selected programs different in the internal memory, presses operation (RUN) key again, and the back is by returning (RETURN) key, working procedure.At this moment, on the one hand can be with literal, chart, curve and the animated graphs of desire demonstration, electric signal, be added on the liquid crystal display device by X, Y driver, realized demonstration, the catoptron of LCD should be peelled off in advance, just become the transmission-type liquid crystal device, be placed on the position of LCD among Fig. 1,, realize that on screen large tracts of land shows through optical projection; Also available on the other hand four look drawing printers (FA-10), content displayed is printed on the recording chart simultaneously on the liquid crystal device of optical system inside with placing, and is placed on that shown content ， And gives over to record on the liquid crystal device at a distance so that the operator monitors.

In the course of work of above-mentioned Fig. 5, the display board that imagination railway station, Chongqing, the starting station No. 561 slow trains are left on LCD such as Fig. 6, through No. 303 expresses (on schedule) display board at station, Chongqing such as Fig. 7, through No. 303 express (late) display boards such as the Fig. 8 at station, Chongqing.Each train number to ETAD expected time of arrival and departure and platform ordinal number, person on duty can get final product according to situation operand keyboard at that time.

On LCD, demonstrating is the English bulletin of incoming flight (supplying the foreign guest to watch) of airport, Chengdu imagination again.The arrival of 4102 flights bulletin is as Fig. 9, and wherein ARRlVALS is for approaching, BEIJING-CHENGDU be Beijing to Chengdu, FLTGHT NO. is a flight number, SCHEDULED is for stipulating (arrival) time result such as Figure 10 that the while printer is got; This flight cancellation bulletin is as Figure 11.Wherein CONCELLATIONS is cancellation, result such as Figure 12 that the while printer is got.

If necessary, as among Fig. 5 with an external magnetic tape station, by the socket of FA-10 interface, realize between magnetic tape station (CM-1) and the external magnetic tape station in the PB-700 microsystem transmission data or program mutually.

If necessary, in Fig. 5, with the socket of the FA-10 interface in the PB-700 microsystem, the socket by the FA-10 interface in cable and another PB-700 microsystem links to each other, and can realize between two PB-700 microsystems swap data and program mutually.

Electrical information with X, the output of Y driver in the computing machine is supplied with the matrix type liquid crystal device, and the liquid crystal large screen projection of realizing shows thus, is applicable to all public arenas, such as station, harbour, airport, park, public place of entertainment, gymnasium etc.; Also electronic game, advertisement can be done altogether the propaganda of shopper window or outdoor advertising uses; Also the information of computing machine output can be watched for many people to giant-screen by crystal projection, convenience is provided for occasions such as teaching, lecture, military commanding.

Also the driving electric signal of the decoder driver of electronic timer (as liquid crystal electron table, electronic clock) can be defeated by liquid crystal device and do above-mentioned Projection Display, thus realize month, day, what day, the time, minute, second large screen display, watch for many people.

Change colourless (or sky-blue) polaroid on the LCD polaroid of certain color into, can on same device, realize showing the demonstration that changes certain color word into from surplus.For example the train number of train slow train shows with surplus, and the train number of express shows with The Scarlet Letter.Because of red polaroid falls the visible absorption of the non-redness of major part, only that the numeral of train number is red with red polaroid demonstration as far as possible, other Chinese character and numeral still use colourless (or sky-blue) polaroid to show black, to improve black white contrast.The double replacement mutually of colourless polaroid and red polaroid can adopt a simple mechanical device to realize.The monochrome that just can realize a large-area width of cloth white and black displays or certain color of the width of cloth with projection pattern on giant-screen shows; The perhaps demonstration that haves both at the same time of a width of cloth black and white and certain color, this is that other display mode (except CRT and the four look electromagnetic and mechanical turnover panels) institute is unapproachable.

(for example existing 160 * 64 pixels, display areas are 105 * 42mm also can to adopt matrix form transmission type colour liquid crystal display device by the synthetic color pixel of red, green, blue three primary colours ²The commodity device), can realize on screen that by projection large-area colour shows.

Liquid crystal display device has certain visual angle.As liquid crystal display device is projected on the giant-screen, display view angle greatly improves, thereby is better than the large screen display that other are made up of a plurality of liquid crystal devices, latter visual angle limited (meander configuration is ± 45 °).

If any further needs, can select wide operating temperature range (5 ℃ to 62 ℃) And and be the high mass moment configuration liquid crystal display device of long-life (100,000 hours).

Several large tracts of land commonly used show comparison such as the table 1 that the large tracts of land with a single liquid crystal device projection shows.

By table 1 as seen, the large tracts of land of single liquid crystal device projection shows, show than several large tracts of land commonly used, the former ratio of performance to price ( ^Performance _Price) and reliability more excellent.

Five, realize best way of the present utility model

Less when the information content that shows a width of cloth picture, transformable picture width of cloth number is advisable to adopt less LCD and the less microcomputer of internal memory of area, for example the PB-700 type not for a long time.When the information content that shows a width of cloth picture medium, when transformable picture width of cloth number is medium, be advisable to adopt medium LCD and the bigger microcomputer of internal memory of area, FP-200 type portable microcomputer for example, its liquid crystal display area is about a times of PB-700, Aspect Ratio is reasonable than PB-700, and pixel is 64 * 160 points, and the minifloppy driver is still arranged.When the information content that shows a width of cloth picture a lot, transformable picture width of cloth number is extremely many, is advisable to adopt bigger LCD and the very big microcomputer of internal memory of area, for example STM-PC type portable microcomputer, its liquid crystal display itself is the transmission-type device, the about 80 * 250mm of display area ², pixel is 200 * 600 points, internal memory 512KB has two independently floppy disk drivers.Also can adopt the common microcomputer with the demonstration of CRT do, but will change on circuit, enable and be with X, the LCD of Y driver is suitable.

Liquid crystal device is convenient to match with cmos driver to select being advisable of 90 ° of distortion field effects for use; As adopting dynamic scattering effect, driving voltage and power consumption are all higher.

Claims (3)

1, the variation of its demonstration of a kind of crystal projection large screen display device is produced by a liquid crystal display device between projection light source and screen, it is characterized in that the driving electric signal that liquid crystal device is shown derives from computing machine, electronic watch, electronic clock, can produce the circuit of character information.

2, device according to claim 1 is characterized in that the change of screen display area is to realize by adjusting a garden dish that is loaded with various different focal objective lens.

3, device according to claim 1 is characterized in that the liquid crystal display device that the liquid crystal display device between light source and display screen can select for use colourless polaroid and monochromatic polaroid to make up, or colour LCD device.

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