WO2000075912A2

WO2000075912A2 - Large display apparatus of modular construction

Info

Publication number: WO2000075912A2
Application number: PCT/IL2000/000306
Authority: WO
Inventors: Ronny Niezni; Gideon Pesah
Original assignee: Comview Graphics Ltd.
Priority date: 1999-06-06
Filing date: 2000-05-29
Publication date: 2000-12-14
Also published as: CA2338597A1; JP2003529090A; AU4776400A; IL130314A0; KR20010072285A; WO2000075912A3

Abstract

Large display apparatus includes a plurality of modular display units each having an image projector for projecting a section of a large composite display, and a light-transmissive screen located and dimensioned with respect to its projector to receive its respective section of the display in a slightly contracted form with respect to the overall display to be viewed, so as to leave a bare margin around the outer edge of a size such that the refraction of the light when transmitted through the screen will diverge the light to the outer edges of the viewing side of the screen, thereby minimizing mullions between adjacent screens without losing any part of the image content of the respective sections of the composite display.

Description

LARGE DISPLAY APPARATUS OF MODULAR CONSTRUCTION

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to large display apparatus of the type comprising a plurality of modular display units each including an image projector and a screen for projecting and displaying a section of a large composite image.

Display systems based on a single image projector are limited in the number of pixels they can display (currently the limit is approximately one million), and in their brightness (the amount of light emitted from a unit image area). In order to exceed these limits, it is necessary to combine several image projectors to create a single image, for example, by arranging a plurality of image projectors with their screens arrayed in a side-by-side array to produce a combined display. The quality of the resulting image, however, critically depends on the ability to suppress discontinuities that may occur at the boundaries of the individual image generators.

One of the contributions to these discontinuities is dark lines or seams between the individual images arising from the overlapping of the edges of the images. These dark lines, commonly called "mullions", produce a "tile" appearance in the overall display and are disturbing to the viewer when visually combining the separate images into one single image. Various techniques have been proposed to reduce the thickness of these mullions without losing image content, but at the present time the mullions are generally in the order of 0.8-8 mm in thickness.

OBJECTS AND BRIEF SUMMARY OF THE INVENTION

An object of the present invention is to provide a large display apparatus having advantages in the above respects.

The large display apparatus of the present invention is of the type comprising a plurality of modular display units each including an image projector for projecting a section of a large composite display, and a light-transmissive screen having a projector side facing its respective projector for receiving its section of the composite display, and a viewing side for viewing its section of the composite display; and a mounting structure for mounting the screens contiguously to each other for viewing the composite display. Such display apparatus will hereinafter be referred to as "large display apparatus of the type herein described".

According to one aspect of the present invention, there is provided large display apparatus of the type herein described, wherein each of the screens is located and dimensioned with respect to its projector to receive, on its projector side, its respective section of the display in a slightly contracted form with respect to the overall display to be viewed, so as to leave a bare margin around the outer edge of the projector side of the screen of a size such that the refraction of the light when transmitted through the screen will diverge the light to the outer edges of the viewing side of the respective screen, thereby minimizing mullions between adjacent screens without losing any part of the image content of the respective sections of the composite display viewed through the viewing sides of the screens.

According to further features described with respect to this aspect of the invention, the mounting structure includes screen frame elements located on the projector sides of the screens. Each of the screens is formed with tapered sides tapering outwardly from the projector side of the screen towards the viewing side of the screen. The screen frame elements are interposed between the edges of adjacent screens and are of a complementary tapered thickness, decreasing to zero at the viewing sides of the screens.

According to another aspect of the present invention, there is provided large display apparatus of the type herein described, wherein the plurality of screens are mounted in a side-by-side relationship to define at least one horizontal row, one of the screens being fixed to the mounting structure, and the remaining screens in the horizontal row being movably mounted to the mounting structure and being urged towards the fixed screen, to accommodate differences in expansion and contraction between the screens and the mounting structure due to temperature fluctuations. According to a further aspect of the invention, there is provided large display apparatus of the type herein described wherein each of the screens is mounted for adjustment towards and away from its respective image projector to permit all the screens to be individually adjusted such that their viewing sides are substantially aligned with each other and occupy a common plane.

As will be described more particularly below, large display apparatus may be constructed in accordance with the foregoing features wherein the size of the mullions between two adjacent screens is reduced from about 0.8-8 mm, as in the existing systems, to about 0.2-0.3 mm. Mullions of such reduced size are practically non-discemable from the normal viewing distance of this type of large display apparatus, e.g., of about three meters or more; and therefore the large display viewed from such a screen is substantially mullions-free. Moreover, such a mullion-free display is attainable without losing any part of the information content to be displayed. Further, this mullion-free condition is maintained despite differences in expansion and contraction between the screens and the mounting structure arising from fluctuations in the ambient temperature. Finally, each of the screens may be initially adjusted, and readjusted whenever desired, to produce a substantially flat, continuous, non-interrupted view of the composite display produced by all the screens.

Further features and advantages of the invention will be apparent from the description below.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:

Fig. 1 is a three-dimensional view illustrating one form of large display apparatus constructed in accordance with the present invention constituted of a plurality of modular display units mounted on a common mounting structure; Fig. 2 illustrates a ball-type mounting element, and Fig. 2a illustrates a roller-type mounting element, for mounting the screens to the mounting structure in the display apparatus of Fig. 1;

Fig. 3 illustrates one of the plurality of modular display units in the apparatus of Fig. 1, including its image projector and its respective screen;

Fig. 4 more particularly illustrates the construction of one of the screens in the modular display unit and two side frame elements for holding the respective screen;

Fig. 5 illustrates the manner in which two adjacent screens are held together by the frame elements;

Fig. 6 illustrates one manner of securing together the two panels of each screen by the use of adhesive tape;

Fig. 7 is an enlarged fragmentary view more particularly illustrating the use of adhesive tape for securing the two panels of a screen;

Fig. 8 illustrates another manner of securing together the two panels of a screen, namely by the use of pins;

Fig. 9 is an enlarged sectional view through a portion of Fig. 8;

Fig. 10 illustrates the manner of adjusting each screen with respect to its projector to provide a flat, uniform, viewing face in the screen array;

Fig. 11 is an enlarged side view of a portion of Fig. 10; and

Fig. 12 illustrates a screen array including a large common screen overlying the individual screens of the individual modular units.

DESCRIPTION OF PREFERRED EMBODIMENTS

The large display apparatus illustrated in Fig. 1 includes a plurality of modular display units, each generally designated 2, mounted on a common mounting structure 3. Each modular unit includes a housing 4 housing an image projector 5 (Fig. 3), and a screen 6 for displaying the image projected by its projector.

There may be any desired number of modular display units 2, according to the size of the overall display. For purposes of example, Fig. 1 illustrates six such units 2 mounted in a rectangular array of two horizontal rows and three vertical columns.

The projector housings 4 are bolted to each other and to the mounting structure 3, such that they are relatively immovable with respect to each other and to the mounting structure. The screens 6 of the projector units 4, however, are secured by frames 7 (Figs. 4 and 5) in a manner to form an overall array 8 which: (1) is virtually mullion-free; (2) maintains the mullion-free appearance in the overall screen even during temperature fluctuations producing different expansions and contractions between the individual screens and the mounting structure 3 and projector units 4; and (3) permits each screen to be individually adjusted towards or away from its respective modular unit, to enable initially prefixing, and later re-fixing whenever desired, each of the screens 6 to produce a flat, uniform appearance in the overall screen array.

The construction of each of the screens 6, and the manner in which the plurality of screens are held by frames 7 to form the common screen array 8, are shown on Figs. 3-7.

With reference first to Fig. 3, it will be seen that each screen 6 is constructed of an inner light-transmissive panel 10 facing the projector 5, and an outer light-transmissive panel 11 facing away from the projector. Thus, the inner face 10a of panel 10, facing the projector 5, constitutes the projector side of the screen 6; and the outer face 11a of the outer panel 11 constitutes the viewing side of the screen.

Face 10b of panel 6 (facing face lib of panel 11) is of a Fresnel construction to collimate the light before reaching panel 11. Panel 11 is made to be light-diffusive so as to scatter the light passing through this panel. There may be a small air gap between faces 10b, lib of the two panels 10, 11. Panel 10 which imparts strength to the screen assembly 8, is preferably from 3-10 mm in thickness; whereas panel 11 is preferably in the order of 3 mm in thickness. The air gap between the two panels is preferably 0-1 mm.

As shown in Fig. 3, the light from projector 5 received on the projector face 10a of panel 10 is refracted as it passes through panel 10 before reaching the Fresnel face 10b, where the light is collimated so as to proceed along parallel paths towards panel 11. It will thus be seen from Fig. 3 that the light reaching the outer edge 10c of the collimating face 10b of panel 10 will enter panel 10 along entry line lOd of the projector face 10a of panel 10. Entry lines lOd are inwardly spaced from the panel outer edge 10c such that a bare margin lOe is produced around the outer edges of the projector face 10a of panel 10. This bare margin lOe around the outer edges of the projector face 10a of panel 10 is used for framing each screen so that the plurality of screens 6 are held in the common screen assembly 8 in a manner which minimizes mullions between adjacent screens without losing any part of the displayed information from the respective projector 5.

Thus, as shown in Figs. 4 and 5, each of the panels 10 is formed with outer edges lOf which taper outwardly from the projector side 10a towards side 10b of panel 10 facing the viewing side 11a of the screen 6 according to the light-refraction line lOd-lOc in Fig. 3. In addition, each of the screen frames 7 is of a complementary tapered thickness, as shown at 7a, such that the thickness of these decreases to zero at the viewing face 10b of panel 10. The screen frames 7 may be fixed to the respective screens 6 by adhesive applied to faces 7a of the frames, and/or to faces lOf of the screen panels 10.

Fig. 4 illustrates the manner of using the frames 7 for framing one of the screens 6; whereas Fig. 5 illustrates the mullion-free appearance resulting when two such screens are supported in a side-by-side relationship.

The two panels 10, 11 of each screen 6 may be attached together in any suitable manner. Figs. 6 and 7 illustrate the use of a thin adhesive tape 12 for this purpose. The adhesive tape should be as thin as possible, preferably about 0.05 mm, so as to maintain the mullion-free appearance in the screen assembly 8 when viewed from the normal viewing distance of 3 meters or more.

Figs. 8 and 9 illustrate another possible manner of fixing the two panels 10, 11 of each screen. In this case, the two panels are fixed by pressure-fitted pins 13 inserted through the two panels to retain the two panels together by friction.

The manner of mounting the screen assembly 8 illustrated in Figs. 1 and 2 maintains the mullion-free appearance during temperature fluctuations producing differences in expansion and contraction between the individual screens 6 and the mounting structure 3 and modular units 4. Thus, only the screen 6 at the center of the lowest horizontal row in the screen assembly 8 is fixed, at its bottom center point, to the mounting structure 3, to which the modular units 4 are also fixed; whereas the remainder of that screen on the opposite sides of its bottom center point, as well as the other screens in the lower horizontal row, are movabiy mounted with respect to the modular units and their mounting structure.

This is shown in Fig. 1, except that the center screen 6 in the lowest horizontal row has been omitted to better illustrate this construction. Thus, as shown in Fig. 1, the center screen 6 is secured at location 15, which is the bottom center of that screen, to the modular units 4 and their mounting structure 3, whereas the remaining portions of the center screen, as well as the other screens on its opposite sides, are supported on mounting structure 3 by balls 16. As shown in Fig. 2, each of these balls 16 is mounted within a housing 17 carried by the mounting structure 3 and supports the respective portion of screen 6 in a manner permitting the screen array to move along two axes. Each of the ball mounting 16 is provided at each of the corners of the screens 6.

Fig. 2a illustrates the modification wherein rollers 18 are used permitting the screen array to move along an axis.

As further shown in Fig. 1, the movable end screens 6 are urged towards the fixed middle screen 6 by leaf springs 19 at the opposite ends of the horizontal row of screens. One end 19a of each leaf spring 19 is fixed to the respective modular unit 4, whereas the opposite end 19b engages the outer edge of the outer screen 6 urging it towards the center screen fixed at 15 to the modular units 4 and their mounting structure 3, as described above. It is only necessary to provide the leaf springs 19 for the lower row of screens 6 since the weight of the screens in the higher row produce sufficient friction acting on the screens in the lower row to cause the higher row screens to move with those of the lower row.

Figs. 10 and 11 illustrate the manner in which each screen 6 may be adjusted towards or away from its respective projector unit 4 in order to produce a flat, uniform appearance in the screen assembly 8.

As shown in Fig. 10, the frame 7 of each screen 6 is provided, at each of its four corners, with a tongue 20 passing through an opening 21 in the respective projector housing 4 and connected by spring 22 to a fixed element 23 of the projector housing. The springs 22 at the four corners of each screen 6 thus urge the screen towards its respective projector housing 4.

Each screen, however, is adjustably spaced from the projector housing 4 by a threaded pin 24 having an enlarged head 25 engageable with the respective corner of the screen frame 7 under the action of spring 22. Head 25 may be manually rotated to preset it towards or away from its projector housing 4 and locked by lock nut 26. Each screen frame 7 is coupled to its respective modular unit housing 4 by a loop 27 fixed to each corner of the modular unit engaging a hook 28 carried by the frame 7, permitting the movement of the respective framed screen 6 toward, away from, or laterally with respect to, housing 4 of its respective modular unit 2. As shown by the side view of Fig. 4, the loop 7 and hook 28 are oriented upwardly at one side and downwardly at the opposite side.

Fig. 12 illustrates a further variation wherein each of the screens for each of the projector units 34 is of a single panel construction, namely including the Fresnel panel corresponding to panel 10 of Figs. 3-5. In this modification, each of the screens, shown at 36 in Fig. 11, is mounted in the same manner utilizing the screen fixing frames, therein designating 37, as described above with respect to Figs. 3-5 to produce the mullion-free screen assembly. However, instead of providing a separate diffusive panel, corresponding to panel 11 in Figs. 3-5, for each modular projector unit 34, a large, common diffusive panel 38 is provided overlying all the screens 36 of the modular projector units 34.

As shown in Fig. 12, the large common screen 38 is spaced from the Fresnel screens 36. Therefore, the Fresnel screens 36 should produce a slight divergence of the light, as shown in Fig. 12, so as to produce the mullion-free display on the common screen 37 without loss of any image content from the respective projector unit 34.

While the invention has been described with respect to several preferred embodiments, it will be appreciated that these are set forth merely for purposes of example, and that many other variations, modifications and applications of the invention may be made.

Claims

WHAT IS CLAIMED IS:

1. Large display apparatus, comprising: a plurality of modular display units each including an image projector for projecting a section of a large composite display, and a light-transmissive screen having a projector side facing its respective projector for receiving its section of the composite display, and a viewing side for viewing its section of the composite display; and a mounting structure for mounting said screens contiguously to each other for viewing the composite display; each of said screens being located and dimensioned with respect to its projector to receive, on its projector side, its respective section of the display in a slightly contracted form with respect to the overall display to be viewed, so as to leave a bare margin around the outer edge of the projector side of the screen of a size such that the refraction of the light when transmitted through the screen will diverge the light to the outer edges of the viewing side of the respective screen, thereby minimizing mullions between adjacent screens without losing any part of the image content of the respective sections of the composite display viewed through the viewing sides of the screens.

2. The apparatus according to Claim 1, wherein said mounting structure includes screen frame elements located on the projector sides of said screens.

3. The apparatus according to Claim 2, wherein each of said screens is formed with tapered sides tapering outwardly from the projector side of the screen towards the viewing side of the screen; said screen frame elements being interposed between the edges of adjacent screens and being of a complementary tapered thickness, decreasing to zero at the viewing sides of the screens.

4. The apparatus according to Claim 1, wherein each of said screens includes a Fresnel panel on the projector side of the respective screen for collimating the light received from the respective projector, and a diffuser panel on the viewing side of the screen for viewing the respective section of the composite display.

5. The apparatus according to Claim 4, wherein the face of said diffuser panel facing said Fresnel panel is formed with a diffusing surface.

6. The apparatus according to Claim 5, wherein said Fresnel panel and diffuser panel are secured to each other by thin adhesive tape applied along the edges of the two panels.

7. The apparatus according to Claim 5, wherein said Fresnel panel and diffuser are secured to each other by pins passing through the two panels.

8. The apparatus according to Claim 1, wherein each of said screens includes a Fresnel panel, said apparatus further including a common screen overlying all said Fresnel panels; said Fresnel panels producing a slight divergence of the light passing therethrough to said common screen such as to minimize the mullions between adjacent sections of the display thereon without losing any part of the composite display received on said common screen.

9. The apparatus according to Claim 1, wherein said plurality of screens are mounted in a side-by-side relationship to define at least one horizontal row.

10. The apparatus according to Claim 9, wherein one of said screens is fixed to said mounting structure, and the remaining screens in the horizontal row are movably mounted to the mounting structure and are urged towards the fixed screen, to accommodate differences in expansion and contraction between the screens and the mounting structure due to temperature fluctuations.

11. The apparatus according to Claim 10, wherein said movably-mounted screens are urged towards said fixed screen by springs at the opposite ends of the horizontal row of screens.

12. The apparatus according to Claim 11, wherein said movably-mounted screens are supported on rolling elements permitting movement of the screens along at least one axis.

13. The apparatus according to Claim 11, wherein said fixed screen is fixed at a central portion thereof to said mounting structure, the remaining portion of said fixed screen also being supported such as to permit movement thereof with respect to said fixed portion of the fixed screen.

14. The apparatus according to Claim 10, wherein said plurality of screens are mounted in side-by-side relation to define a rectangular matrix of a plurality of horizontal rows and a plurality of vertical columns, the center screen in the lowermost row being fixed at one point to the mounting structure.

15. The apparatus according to Claim 1, wherein each of said screens is mounted for adjustment towards and away from its respective image projector to permit all the screens to be individually adjusted such that their viewing sides are substantially aligned with each other and occupy a common plane.

16. The apparatus according to Claim 15, wherein each of said screens includes a spring urging it towards its projector, and an adjustable spacer element permitting adjustment of the space between the screen and its respective projector.

17. The apparatus according to Claim 16, wherein said adjustable spacer elements are threaded pins having heads threadedly adjustable towards and away from the respective projector.

18. The apparatus according to Claim 16, wherein each of said screens is provided with an adjustable spacer element at each of its corners.

19. Large display apparatus, comprising: a plurality of modular display units each including an image projector for projecting a section of a large composite display, and a light-transmissive screen having a projector side facing its respective projector for receiving its section of the composite display, and a viewing side for viewing its section of the composite display; and a mounting structure for mounting said screens contiguously to each other for viewing the composite display; said plurality of screens being mounted in a side-by-side relationship to define at least one horizontal row; one of said screens being fixed to said mounting structure, and the remaining screens in the horizontal row being movably mounted to the mounting structure and urged towards the fixed screen, to accommodate differences in expansion and contraction between the screens and the mounting structure due to temperature fluctuations.

20. The apparatus according to Claim 19, wherein said movably-mounted screens are urged towards said fixed screen by springs at the opposite ends of the horizontal row of screens.

21. The apparatus according to Claim 20, wherein said movably-mounted screens are supported on rolling elements permitting movement of the screens along at least one axis.

22. The apparatus according to Claim 21, wherein said fixed screen is fixed at a central portion thereof to said mounting structure, the remaining portion of said fixed screen also being supported such as to permit movement thereof with respect to said fixed portion of the fixed screen.

23. The apparatus according to Claim 19, wherein said plurality of screens are mounted in side-by-side relation to define a rectangular matrix of a plurality of horizontal rows and a plurality of vertical columns, the center screen in the lowermost row being fixed at one point to the mounting structure.

24. Large display apparatus comprising: a plurality of modular display units each including an image projector for projecting a section of a large composite side facing its respective projector for receiving its section of the composite display, and a viewing side for viewing its section of the composite display; and a mounting structure for mounting said screens contiguously to each other for viewing the composite display; said plurality of screens being mounted in a side-by-side relationship to define at least one horizontal row; each of said screens being mounted for adjustment towards and away from its respective image projector to permit all the screens to be individually adjusted such that their viewing sides are substantially aligned with each other and occupy a common plane.

25. The apparatus according to Claim 24, wherein each of said screens includes a spring urging it towards its projector, and an adjustable spacer element permitting adjustment of the space between the screen and its respective projector.

26. The apparatus according to Claim 25, wherein said adjustable spacer elements are threaded pins having heads threadedly adjustable towards and away from the respective projector.

27. The apparatus according to Claim 24, wherein each of said screens is provided with an adjustable spacer element at each of its corners.

28. The apparatus according to Claim 24, wherein each of said screens is coupled to its respective image projector by a hook and loop coupling which permits movement of the screen toward, away from, and laterally with respect to its respective modular unit.