DK174827B1 - Back-lit projection screen - Google Patents

Back-lit projection screen Download PDF

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DK174827B1
DK174827B1 DK178191A DK178191A DK174827B1 DK 174827 B1 DK174827 B1 DK 174827B1 DK 178191 A DK178191 A DK 178191A DK 178191 A DK178191 A DK 178191A DK 174827 B1 DK174827 B1 DK 174827B1
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DK
Denmark
Prior art keywords
projection screen
screen according
lenses
light
taillight
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DK178191A
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Danish (da)
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DK178191D0 (en
DK178191A (en
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Johannes Clausen
Erik Clausen
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Dainippon Printing Co Ltd
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Publication of DK178191A publication Critical patent/DK178191A/en
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Abstract

A transparent back-lit projection screen for use in, for example, video projection, consisting of three screen elements, of which the first element, which faces the light source, is a Fresnel lens and the middle element on the input side has lens sections for spreading the light in a horizontal plane, and where in addition the output side has lenses for the paralleling of the light from several sources of light, and where the foremost image-forming element on the input side has horizontally running convex rectilinear lenses, whose focal distance coincides with the output side's slip top, and where this top's face has an inclination which is different from the screen's face.<IMAGE>

Description

i DK 174827 B1in DK 174827 B1

Den foreliggende opfindelse angår en baglysprojektionsskærm bestående af tre skærmelementer, hvoraf det bageste element, som vender mod projektorerne, tjener til parallelisering af lyset fra projektorer-5 ne, det mellemste element tjener til spredning af lyset i horisontalt plan samt parallelisering af lyset fra de tre lysgivere, og det forreste element, som er det billeddannende element, har på sin bagside i skærmens brugsstilling horisontale retlinjede paral-10 lelt forløbende konvekse linser, hvis brændvidde er tilnærmelsesvis lig med skærmelementets tykkelse, og som på sin forside har retlinjede horisontalt forløbende kamme, fra hvis toppe lyset kan udstråle, og hvor disse toppes overflade danner en vinkel med 15 skærmens plan, og hvori der endvidere mellem kammene 1 s toppe er fordybninger, som afdækkes med lysuigennemtrængeligt materiale, f. eks. sort farve, til forøgelse af kontrasten.The present invention relates to a rear light projection screen consisting of three screen elements, the rear element facing the projectors serving to parallelize the light from the projectors, the middle element serving to scatter the light horizontally and parallelizing the light from the three light emitters, and the front member, which is the imaging member, has horizontal rectangular parallel convex lenses at its rear in the position of use, the focal length of which is approximately equal to the thickness of the screen member and which at its front has a rectangular horizontal from which the tops can radiate the light, and where the tops of these peaks form an angle with the plane of the screen, and furthermore, between the tops of the cams 1 s there are recesses covered with light-impervious material, for example black color, to increase the contrast.

Baglysprojektionsskærme anvendes i vidt omfang 20 til videoprojektionsapparater, mikrofilmlæseapparater, datamaskiner og flysimulatorer.Rear light projection screens are widely used for video projection devices, microfilm readers, computers and flight simulators.

Fra beskrivelse US Patent No. 4,923,280 kendes en baglysprojektionsskærm med horisontalt forløbende linsetoppe, og hvor der mellem disse toppe er lysab-25 sorberende farve. Disse toppes overflade er oftest blank, hvilket kan medføre en generende spejling af omgivelserne eller tilbagekastning af lysstråler fra en eller flere lyskilder. Ved forsøg har det vist sig, at denne generende spejling ikke kan fjernes ved 30 f. eks. at coate overfladen semimat eller mat. Det er formålet med den foreliggende opfindelse at forhindre generende spejling fra skærmens overflade.From Description US Patent No. 4,923,280 discloses a taillight projection screen with horizontally extending lens peaks, and where there is light absorbing color between these peaks. The tops of these peaks are usually glossy, which can cause a nuisance reflection of the surroundings or the reflection of light rays from one or more light sources. In experiments, it has been found that this annoying mirror cannot be removed by, for example, coating the surface semi-matte or matte. It is the object of the present invention to prevent nuisance mirroring from the screen surface.

DK 174827 B1 2DK 174827 B1 2

Det er kendt at frembringe et projiceret TV-billede, ved at rette tre projektorer med hver sin grundfarve (rød, grøn og blå) mod en transparent projektionsskærm. De tre projektorer er som regel an-5 bragt ved siden af hinanden horisontalt, og det afgående, forstørrede billede er rettet mod den transparente skærm. På grund af, at de tre projektorer er anbragt ved siden af hinanden, danner deres optiske akser vinkler med hinanden. Normalt danner de optiske 10 akser vinkler med hinanden fra 7° til 12°, afhængigt af billedrorets størrelse og afstanden fra billedror til transmissionsskærm.It is known to produce a projected TV image, by aiming three projectors with each different basic color (red, green and blue) against a transparent projection screen. The three projectors are usually arranged side-by-side horizontally, and the outgoing, magnified image is aimed at the transparent screen. Because the three projectors are arranged side by side, their optical axes form angles with each other. Typically, the optical 10 axes form angles with each other from 7 ° to 12 °, depending on the size of the picture frame and the distance from picture frame to transmission screen.

De fleste konstruktører af projektions-TV placerer det grønne billedror mellem det røde og blå, 15 således at det grønne billedes optiske akse projiceres vinkelret ind på den transmitterende skærm. Dette medfører, at det blå og røde billedrors optiske akser afviger med f. eks. 9° i forhold til det grønne billedrors optiske akse.Most projection TV designers place the green picture frame between the red and blue, 15 so that the optical axis of the green image is projected perpendicular to the transmitting screen. As a result, the optical axis of the blue and red image deviates by, for example, 9 ° from the optical axis of the green image mirror.

2 0 Det er kendt, som vist i fig. 2, at konstruere en TV-baglysprojektionsskærm, der er anbragt i skærmen 7's brugsstilling med de parallelle konvekse linser 9 og 10 vertikalt løbende, og hvor 7a angiver en fresnellinse til parallelisering af lyset, 7b angiver 25 den bi11eddannende skærm med linsen 9, hvis brændpunkt sammenfalder med linsen 10’s overflade, og hvor der mellem de konvekse linser 10 er anbragt kamme 12 til påføring af afdækningsstriberne for at øge kontrasten.It is known, as shown in FIG. 2, to construct a TV rear projection screen positioned in the operating position of the screen 7 with the parallel convex lenses 9 and 10 vertically continuous, and wherein 7a indicates a fresnel lens for parallelizing the light, 7b indicates the image forming screen with the lens 9, the focal point of which coincides with the surface of the lens 10, and where the convex lenses 10 are provided with ridges 12 for applying the cover strips to increase the contrast.

30 Da linsen 9 kun tjener til spredning af lyset horisontalt, kan skærmen tilsættes glaspulver eller Si02 pulver til spredning af lyset i vertikal retning.30 Since the lens 9 serves only for scattering the light horizontally, the screen may be added to glass powder or SiO 2 powder for scattering the light in the vertical direction.

3 DK 174827 B13 DK 174827 B1

Lyset fra skarmen 7b vil blive afbøjet af linse 71, hvis brændpunkt er sammenfaldende med overfladen 73 af linsetoppen 72.The light from the screen 7b will be deflected by lens 71, the focal point of which coincides with the surface 73 of the lens top 72.

Det er blandt fagfolk kendt, at en blank over-5 flade med en mørk baggrund giver en generende spejling i et oplyst rum.It is known to those skilled in the art that a glossy over-5 surface with a dark background provides a nuisance reflection in an illuminated room.

Det er formålet med den foreliggende opfindelse at afbøje indfaldende lysstråler på en sådan måde, at disse reflekteres uden for en iagttagers synsfelt.It is the object of the present invention to deflect incident light rays in such a way that they are reflected outside the field of view of an observer.

10 Baglysprojektionsskærm iflg. den foreliggende opfindelse er kendetegnet derved, at hver enkelt linsetops overflade/krumning danner en vinkel med hele skærmens plan.10 Taillight projection screen according to The present invention is characterized in that the surface / curvature of each lens top forms an angle with the entire screen plane.

Opfindelsen skal herefter forklares nærmere un- 15 der henvisning til tegningen, hvor fig. 1. viser et farveprojektions TV-system, bestående af tredelt projektionsskærm til forklaring af anvendelse af projektionsskærm af den her omhandlede art, 20 fig. 2. viser et perspektivisk udsnit af en kendt udførelsesform, fig. 3. viser en skærm delt i tre sektioner iflg. den foreliggende opfindelse, fig. 4. viser lysrefleksioner af rumlys iflg.The invention will now be explained in more detail with reference to the drawing, in which fig. 1 shows a color projection TV system consisting of three-part projection screen for explaining the use of a projection screen of the kind in question; FIG. 2 is a perspective view of a known embodiment; FIG. 3. shows a screen divided into three sections according to. FIG. 4. shows light reflections of room light according to.

25 den foreliggende opfindelse, fig. 5. viser refleksion af lysstråle til en anden anvendelse for den foreliggende opfindelse, fig. 6. viser et mindre tværsnit af den kendte skærm 7c i fig. 2, 30 fig. 7 viser et mindre udsnit af skærmen i fig.25 of the present invention; FIG. 5. shows reflection of light beam for another application of the present invention; 6 shows a smaller cross-section of the known screen 7c in FIG. 2, FIG. 7 shows a smaller section of the screen of FIG.

3 iflg. den foreliggende opfindelse, fig. 8a viser lystransmissionen gennem et udsnit af skærmen iflg. den foreliggende opfindelse, DK 174827 B1 4 fig. 8b viser en anden udførelsesform af den foreliggende opfindelse, fig. 9 viser et mindre tværsnit iflg. den foreliggende opfindelse, hvor indgangslinsen er asymme-5 trisk, fig. 10. viser et udsnit iflg. den foreliggende opfindelse, hvor linsekammens symmetriakse ikke er normal til billedskærmens plan, fig. 11 og 12 viser andre udførelsesformer, 10 hvor linsernes overflader er krumme, fig. 13 og 14 viser andre udførelsesformer af linsekammenes overfladetoppe, fig. 15 og 16 viser endnu to udførelsesformer af den foreliggende opfindelse, og 15 fig. 17 viser et eksempel på måleforhold iflg.3 according to FIG. 8a shows the light transmission through a section of the screen according to. The present invention, DK 174827 B1 4 FIG. 8b shows another embodiment of the present invention; 9 shows a smaller cross section according to. the present invention wherein the input lens is asymmetrical; 10. shows a section according to. the present invention in which the axis of symmetry of the lens is not normal to the plane of the display screen; 11 and 12 show other embodiments 10 where the surfaces of the lenses are curved; FIG. 13 and 14 show other embodiments of the tops of the lens combs; FIG. 15 and 16 illustrate two further embodiments of the present invention; 17 shows an example of measurement conditions according to.

den foreliggende opfindelse.the present invention.

Fig. 1 viser, hvorledes de tre projektorer 1, 2 og 3 projicerer fjernsynsbilleder mod bagsiden af en projektionsskærm 7. Hver projektor afgiver henholds- 2 0 vis grønt, rødt og blåt lys. De tre projektorer er anbragt ved siden af hinanden horisontalt således, at projektor 2, som oftest er den grønne projektor, har sin optiske akse vinkelret på skærmen 7.FIG. 1 shows how the three projectors 1, 2 and 3 project television images towards the back of a projection screen 7. Each projector emits green, red and blue light respectively. The three projectors are arranged side by side horizontally so that projector 2, most often the green projector, has its optical axis perpendicular to the screen 7.

De optiske akser for projektorerne 1 og 3 dan-25 ner ofte en vinkel på 8° - 12° i forhold til projektor 2.The optical axes of projectors 1 and 3 often form an angle of 8 ° - 12 ° relative to projector 2.

Ved hjælp af de tre projektorer 1, 2 og 3 samt de foran monterede linser 4, 5 og 6 er det muligt at danne et i forhold til projektorerne forstørret bil- 3 0 lede på skærmen. Skærmen 7 kan bestå af akryl eller lign. materiale.With the help of the three projectors 1, 2 and 3 as well as the lenses 4, 5 and 6 mounted in front it is possible to create an enlarged image on the screen relative to the projectors. The screen 7 may consist of acrylic or similar. material.

Fig. 2 viser en udførelsesform i perspektiv af fig. 1.FIG. 2 shows an embodiment in perspective of FIG. First

5 DK 174827 B15 DK 174827 B1

Fig. 3 viser en udførelsesform ifølge den foreliggende opfindelse, hvor 31 betegner en komplet skærm, og 32, 33 og 34 viser udsnit af skærmen til illustration af, at vinklen Vi er forskellig fra V2, 5 som igen er forskellig fra V3.FIG. 3 shows an embodiment of the present invention wherein 31 represents a complete screen and 32, 33 and 34 show sections of the screen to illustrate that the angle Vi is different from V2, 5 which is different from V3.

Fig 4. viser et eksempel på anvendelsen af en projektionsskærm iflg. den foreliggende opfindelse. I fig. 4 angiver 13 et TV-projektionsapparat, 14 angi ver en projektionsskærm af samme konstruktion som 10 fig. 2, dog med den ændring, at linsetoppene 73’s overflade er skrå, som vist på fig. 3 og danner dermed vinkler Vi, V2 og V3 med hele skærmens plan. Som det også fremgår af fig. 4, vil lysstråler fra A og B blive afbøjet på en sådan måde, at disse vil blive 15 reflekteret i retninger, som er uden for en persons synsfelt og derved ikke virker generende.Fig. 4 shows an example of the use of a projection screen according to Figs. the present invention. In FIG. 4 shows 13 a television projection apparatus, 14 indicates a projection screen of the same construction as 10 fig. 2, with the change that the surface of the lens peaks 73 is inclined, as shown in FIG. 3, thus forming angles Vi, V2 and V3 with the entire screen plane. As can also be seen from FIG. 4, light rays from A and B will be deflected in such a way that they will be reflected in directions that are outside a person's field of vision and thus do not appear to be bothersome.

I fig. 7 vises et udsnit 15 af fig. 4 forstørret op. Det fremgår af fig. 7, at de reflekterede stråler fra lyskilderne 18 og 19 bliver reflekteret 20 under større vinkler u3 og u4 end vinklerne u3 og u2 for fig. 4, som er udførelsesformen iflg. den kendte konstruktion.In FIG. 7, a section 15 of FIG. 4 enlarged. It can be seen from FIG. 7, that the reflected rays from the light sources 18 and 19 are reflected 20 at greater angles u3 and u4 than the angles u3 and u2 of FIG. 4, which is the embodiment according to. the known construction.

Fig. 8a viser et forstørret udsnit af skærmen 14 i fig. 4, og som det fremgår af fig. 8a, vil et 25 parallelt lysbundt, som rammer linsen 21 blive transmitteret gennem linsetoppene '20. Derved afbøjes strålerne svarende til hvilket er illustreret med lysstrålen a og a' . En iagttager vil således konstatere større lysintensitet fra et TV-apparatet i brugsstil-30 ling. Det er i øvrigt kendt blandt fagfolk at løfte det udstrømmende lys 6° - 10° i forhold til skærmens normal.FIG. 8a shows an enlarged section of the screen 14 of FIG. 4, and as shown in FIG. 8a, a parallel beam of light striking the lens 21 will be transmitted through the lens peaks '20. Thereby, the rays are deflected correspondingly to that illustrated by the light beam a and a '. Thus, an observer will notice greater light intensity from a television set in use mode. It is also known to those skilled in the art to raise the outgoing light 6 ° - 10 ° relative to the screen normal.

DK 174827 B1 6 I fig. 8b hælder overfladen af linsetoppene 22, modsat fig. 8a, svarende til fig. 5. Ved denne konstruktion vil lysstrålerne fra projektionssystemet blive bøjet ned mod tilskueren, se fig. 5.DK 174827 B1 6 In fig. 8b inclines the surface of the lens peaks 22, opposite to FIG. 8a, similar to FIG. 5. In this construction, the light rays from the projection system will be bent down towards the spectator, see fig. 5th

5 Fig. 9 viser et eksempel på en anden udførel sesform, hvor de v-formede fordybninger mellem forsidelinserne 23 er parallelt forskudt i forhold til fordybningerne mellem de asymmetriske bagsidelinser 24 .FIG. 9 shows an example of another embodiment in which the v-shaped recesses between the front lenses 23 are offset in parallel with the recesses between the asymmetrical rear lenses 24.

10 Fig. 10 viser en udførelsesform, hvor symmetriaksen for linse 25 ikke står vinkelret på skærmens overflade. Ved denne udførelsesform er fordybninger på forside og bagside ud for hinanden.FIG. 10 shows an embodiment in which the axis of symmetry of lens 25 is not perpendicular to the screen surface. In this embodiment, recesses on the front and back are next to each other.

Fig. 11 og 12 viser, at linsetoppene 26 og 27 15 kan være konkave og konvekse samtidig med, at de danner en vinkel i forhold til skærmoverfladen.FIG. 11 and 12 show that the lens peaks 26 and 27 15 can be concave and convex at the same time as they form an angle to the screen surface.

Fig. 13 og 14 viser andre udførelsesformer af linseoverfladerne 28 og 29.FIG. 13 and 14 show other embodiments of the lens surfaces 28 and 29.

Fig. 15 og 16 viser eksempler på andre udform-20 ninger af linsetoppen 30, hvor lyset fra rummet afbøjes og reflekteres ud til siden.FIG. 15 and 16 show examples of other embodiments of the lens top 30, where the light from the room is deflected and reflected to the side.

Fig. 17 viser et eksempel på måleforhold ifølge den foreliggende opfindelse.FIG. 17 shows an example of measurement conditions according to the present invention.

2525

Claims (14)

1. Transparent baglysprojektionsskærm bestående af 3 skærmelementer af den art, hvor det bageste element består af en fresnellinse til parallelisering af 5 bagfra kommende lys, og hvor det mellemste element i skærmens brugsstilling på begge sider af elementet har lodret forløbende, retlinjede konvekse linser, hvis optiske akser i hovedsagen er sammenfaldende, og hvor der mellem de forreste linser er forhøjninger 10 til afmaskning med sort farve, og hvor det forreste bi11eddannende element på sin bagside har retlinjede parallelt forløbende konvekse linser (21; 24), hvis brændvidde tilnærmelsesvis er lig med skærmelementets tykkelse, og som transmitterer bagfra kommende lys 15 til skærmens forside, hvilket lys kun undergår afbøjning ved de linser (23; 25; 30) fra hvis toppes (20; 22; 26; 27; 28; 29; 35; 36) overflade lyset fra linse (21; 24) kan udstråle, og hvorfra der mellem linsernes (23;25,-30) toppe er V-formede fordybninger, som 20 kan afdækkes eller opfyldes med lysuigennemtrængeligt materiale, f. eks. sort farve til forøgelse af kontrasten, kendetegnet ved, at disse toppes overflade hælder i forhold til hele skærmens plan.1. Transparent taillight projection screen consisting of 3 screen elements of the kind in which the rear element consists of a fresnel lens for parallelizing 5 rear-view lights, and wherein the middle element of the display position of use on both sides of the element has vertically extending, rectilinear convex lenses if optical axes are substantially coincident and where between the front lenses are black color masking ridges 10 and the front image forming member at its rear has rectilinear parallel convex lenses (21; 24) whose focal length is approximately equal to the thickness of the screen element and transmitting from behind incoming light 15 to the front of the screen, which light only deflects at the lenses (23; 25; 30) from the top of which (20; 22; 26; 27; 28; 29; 35; 36) the light from lens (21; 24) can radiate, and from which, between the peaks of the lenses (23; 25, -30), are V-shaped recesses that can be uncovered or filled with d light-impervious material, such as black color to increase contrast, characterized by the fact that the tops of these peaks are inclined relative to the entire screen plane. 2. Baglysprojektionsskærm iflg. krav 1 k e n -25detegnet ved, at hældningen af toppenes overflade (20) varierer over skærmens overflade iflg. fig. 3.2. Taillight projection screen according to. Claim 1 characterized in that the inclination of the surface of the peaks (20) varies over the surface of the screen according to. FIG. Third 3. Baglysprojektionsskærm iflg. krav 1 kendetegnet ved, at det mellemste skærmelement 30 indeholder lysbrydende materiale.3. Taillight projection screen according to. Claim 1, characterized in that the middle shield element 30 contains light-breaking material. 4. Baglysprojektionsskærm iflg. krav 1 kendetegnet ved, at det forreste skærmelement indeholder lysbrydende materiale. DK 174827 B14. Taillight projection screen according to. Claim 1, characterized in that the front shield element contains light-breaking material. DK 174827 B1 5. Baglysprojektionsskaerm iflg. krav 1 kendetegnet ved, at fremspringene eller kammene mellem det mellemste forsideelements linser er asymmetriske .5. Taillight projection screen according to. Claim 1, characterized in that the projections or cams between the lenses of the middle front member are asymmetrical. 6. Baglysprojektionsskærm iflg. krav 1-5 kendetegnet ved, at kammenes (12) symmetriakser på forsideelementet ikke er parallelle med linsernes (11) optiske akser.6. Taillight projection screen according. Claims 1 to 5, characterized in that the axes of symmetry (12) of the front element are not parallel to the optical axes of the lenses (11). 7. Baglysprojektionsskaerm iflg. krav 1 k e n -lOdetegnet ved, at det forreste skærmelement har asymmetriske linser (24), se fig. 9.7. Taillight projection screen according to. Claim 1 characterized in that the front shield element has asymmetric lenses (24), see fig. 9th 8. Baglysprojektionsskaerm iflg. krav 7 kendetegnet ved, at de forreste linsekamme (25)'s symmetriakse ikke er parallel med skærmens 15 normal.8. Taillight projection screen according to. Claim 7, characterized in that the axis of symmetry of the front lens combs (25) is not parallel to the normal of the screen 15. 9. Baglysprojektionsskaerm iflg. krav 1 kendetegnet ved, at toppenes overflade er udformet som vist på fig. 13 (28) eller fig. 14 (29).9. Taillight projection screen according to. Claim 1, characterized in that the surface of the peaks is formed as shown in FIG. 13 (28) or FIG. 14 (29). 10. Baglysprojektionsskærm iflg. krav l 20 kendetegnet ved, at overfladen (35) af forsideelementerne toppe er udformet som vist på fig. 15 .10. Taillight projection screen according to. Claim 1 20, characterized in that the surface (35) of the front side peaks is formed as shown in FIG. 15. 11. Baglysprojektionsskærm iflg. krav 1 kendetegnet ved, at overfladen (36) af 25 forsideelementernes toppe er udformet som vist på fig. 16.11. Taillight projection screen according to. Claim 1, characterized in that the surface (36) of the tops of the front side elements is formed as shown in FIG. 16th 12. Baglysprojektionsskærm iflg. krav 1 k e n -detegnet ved måleforhold i henhold til fig. 17.12. Taillight projection screen according. Claim 1 characterized by measurement conditions according to FIG. 17th 13. Baglysprojektionsskærm iflg. krav 1 kendetegnet ved, at overfladen (26) eller (27) af kammenes toppe er konkav eller konveks i henhold til fig. 11 eller fig. 12. DK 174827 B113. Taillight projection screen according to. Claim 1, characterized in that the surface (26) or (27) of the tops of the combs is concave or convex according to FIG. 11 or FIG. 12. DK 174827 B1 14. Baglysprojektionsskærm iflg. krav 1 kendetegnet ved, at linserne på det mellemste skærmelement kan være skiftevis konvekse /konkave . 514. Taillight projection screen according to. Claim 1, characterized in that the lenses on the middle shield element can be alternately convex / concave. 5
DK178191A 1991-10-25 1991-10-25 Back-lit projection screen DK174827B1 (en)

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DK178191A DK178191A (en) 1993-04-26
DK174827B1 true DK174827B1 (en) 2003-12-08

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DK178191A (en) 1993-04-26

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