Alignment mechanism and alignment procedure for tiled displays

Description

[0001] The present invention relates to a tiled display including an intermediary support structure, multiple display tiles and a support structure supporting the multiple display tiles of the tiled display, wherein the intermediary support structure comprises first fastening means for fastening the intermediary support structure to the support structure.Background

[0002] Solutions to align the display tiles of a tiled display are known from the art.

[0003] US10056014 "Positioning and alignment device for tiled displays" describes an alignment mechanism to adjust the relative position of adjacent display tiles as they are assembled to form a tiled display. Figures 1a and 1b show a top view and a section view (along line AB of Fig.1a) of an example of alignment mechanism according to US10,056,014. The alignment mechanism 1 is fastened to a support structure 12 by means of a compliant fastener 2 that is force fitted into an opening 4 present in the support structure 12 and an opening 3 present in the alignment device 1. Two adjacent tiles can be aligned by means of e.g. a pin (on the tile) and hole (like 9 and 10 on the alignment device) combination. The compliance of the fastener 2 allows the compensation of tolerances that affects the position of openings (like 4) in the support structure 12 while the distance between two adjacent tiles is determined by the geometry of the alignment device and in particular the position of the holes (like 9 and 10) in which positioning pins on display tiles will be fitted.

[0004] The alignment mechanism requires extensive manipulation of the tiles and for very small seams (when the distance between adjacent tiles is less than 1 mm), this can become a problem. Indeed, as the dimensions of light emitting elements decrease, they become more fragile and shocks between adjacent tiles during assembly can be enough to damage them and create visual artefacts during operation of the display (dead pixels, discoloration, etc.)

[0005] US20180359426 "Fixture for Aligning Tiled Displays" describes a fixture for adjusting the position of a display tile with respect to adjacent display tiles. The fixture includes a frame that supports a vision system. The vision system is configured to image at predefined display corner positions defined by given display dimensions. As illustrated on Figure 2, the fixture 200 further includes an attachment mechanism configured to attach the frame of the fixture to the display surface 202 of a display tile 201 such that the vision system images positions of the tile and adjacent display corner positions. The fixture can be operated by a technician that will move the tile until its position is nominal (as determined by the vision system). Alternatively, the fixture can be supported by the support structure that supports the display tiles and one or more alignment mechanisms adjust the alignment of the display tile. US20180359426 does not describe where the one or more alignment mechanism can be positioned when the fixture is attached to the front of a display tile nor does it describe how to avoid damaging the LEDs mounted on the display tile (e.g. by scratching the coatings of the LEDs) when the fixture contacts the display tile.

[0006] WO2019 / 034786A1 "Adjustable support structure for display tile" describes a support structure with a built-in tile alignment system wherein collisions between adjacent display tiles are prevented. The support structure comprises several intermediary parts between the load bearing structure (not shown) and the display tile 300. Four elements (only 301, 302 and 303 are shown on Figure 3a) correct irregularities of, for example, a wall to which the display structure will be fastened. A first intermediary part 304 has a fixed position with respect to, for example, the load bearing wall. A second intermediary mechanism 305 allows displacement of the display tile 300 in the display plane xy, a.o. to create a gap around the display tile 300 and grant access to the fastening means 306, that fasten the display tile 300 to the rest of the structure. The fastening means allow movement of the display tile in the z direction. This facilitates, for instance, access to, for example, one or more handles and / or a release mechanism positioned on the lateral sides or backside of the display tile 300, without requiring interaction with the front or display side 307 of the display tile. Shocks between adjacent display tiles are softened by the mechanism 305 (use of, for example, a gas spring, not shown on figure 3a) as well as by corner elements like 308, 309, 310 that can act as bumpers and avoid contact with fragile elements (such as, for example, a glass substrate of a liquid crystal panel or the coating of LEDs) on the display side 307 of the display tile 300.

[0007] As illustrated on Figure 3b, a display tile 300 hangs to fastening means 306 (i.e. no contact with the front surface 307 is required to position the display tile). An operator assembling the tiled display does not have to carry the weight of a display tile while modifying its position in the xy plane. Not having to carry the weight of the tile during assembly means that an operator can concentrate on the precision of the positioning and avoiding shocks to the display surface. The support structure described in WO2019 / 034786A1 limits the risk of damages to the display side of a display tile and facilitates the assembly of display tile into a tiled display, but it requires mechanical precision for the various structures like 301, 304, 305 and 306.

[0008] If there is no access to the back of the tiled display, fastening and unfastening a display tile requires a dedicated mechanism as described in, for instance, WO2019 / 034786A1.

[0009] The art has no solution for using simple and reliable fastening means (like, for example, bolts) that can be accessed from the front of the tiled display, while at the same time allowing to have seams smaller than the fastening means. For instance, using bolts to fasten a display tile to a support structure without access to the back of the support structure, is not possible if the diameter of the bolt is larger than the seam between a tile already fastened to the support structure and an adjacent tile being fastened to the support structure.Summary of the invention

[0010] The invention is defined in claim 1. Optional features are defined in the dependent claims. An intermediary support element can be at least partially or temporarily supported by the support structure during assembly by means of a temporary fastening or fastening means such as magnets, before being fastened in place with a more permanent or semi-permanent joint, such as nuts and bolts. The temporary fastening or fastening means, such as magnets, can be glued or screwed to the intermediary support element. An advantage is that even while the weight of the display tile is supported by the support structure, it is possible to glide the intermediary support element and the display tile attached to it, into position.

[0011] It is an advantage of this aspect of the present invention, that it simplifies the tiling of display tiles when the distance, referred to as the seam between adjacent tiles, is too small to allow access to first fastening means.

[0012] In a further aspect of the present invention, the intermediary support structure has additional fasteningmeans, i.e. second fastening means, to attach the display tile to a tool for alignment of the display tile with one or more display tiles already fastened to the support structure.

[0013] The second fasteningmeans can be on the same side or sides as the fastening or fastening means for fastening to the support structure. In particular, the attachment second fastening means are adjacent to the first fastening means for fastening to the support structure.

[0014] An intermediary support structure can include any of the following. The intermediary support structure can be configured to lie between the display tile and a support structure such as a frame or wall when in operation. The support structure can be a metallic plate. The metallic plate can have first openings optionally located at regular intervals. The first openings are for receiving fasteners or fastening means like e.g. bolts and optionally nuts which are loose or are fixed to the first openings to fasten display tiles to the support structure or to fasten an intermediary structure. The width of a seam, which is the distance between adjacent display tiles, preferably does not allow to access first fastening means through the seam. The intermediary support element has third means for fastening to a support structure. The third fastening means can include second openings. The second openings can each be located on one extremity of three extremities of a Y-shaped or T-shaped device. The intermediary support element can comprise coupling means or fastening means adapted for coupling or fastening the intermediary support element to a display tile. The coupling or fastening means comprises holes that are configured to mate with protrusions such as pins on the display tile. The intermediary support structure can comprise second coupling means configured for manipulating the display tile without risk of damaging the display surface of the display tile. The display tile has a first surface that is a front surface or display surface and a second surface that is a back surface. The back surface has a fastener optionally fastening means to be fastened to the intermediary support element. Once the pins and / or holes of the intermediary support elements and the corresponding holes and pins on the back surface are mated, the display tile and the intermediary support element behave like a solid body. The second coupling means can each be located on one extremity of the Y-shaped or T-shaped device, respectively. The second coupling means include a third opening located adjacent a second opening, respectively.

[0015] A tiled display can include an associated intermediary support structure wherein a first tile is fastened to a support structure by means of its associated intermediary support structure having means of a plurality of fastening means. The plurality of fastening means used to fasten the display tile to the support structure are either on a single side or edge of the display tile or are distributed along two abutting sides or edges. The tiled display can comprise means to manipulate a display tile without having to contact its display surface, the means including a tool fastened to the intermediary support structure by means of fastening means. The display tile in the tiled display is fastened to the tool and is translated and / or rotated by means of one or more motors and the relative position of the display tile with respect to one or two adjacent tiles is monitored by one or more sensors.Brief Description of the figures.

[0016] Figure 1a shows a top view of a tile positioning device according to the prior art. Figure 1b shows a section view of a tile positioning device in accordance with the prior art. Figure 2 illustrates a problem of the prior art (contact with surface of display tile). Figure 3a and 3b illustrate how a complex structure can be used to position a display tile with high precision while limiting contact with the display side of the tile. Figure 4 shows an example of a support structure that can be used with the present invention. Figure 5 shows an example of intermediary support structure according to an embodiment of the present invention. Figure 6 shows an example of a display tile which is assembled according to an embodiment of the present invention. Figures 7a and 7b illustrate an example of fastening means and how they can compensate for the tolerances affecting the support structure. Figures 8a, 8b, 8c, 8d, 8e and 8f show an example of steps to assemble a tiled display in accordance with an embodiment of the present invention. Figures 9a and 9d show how fastening means can be distributed along a single side of the display tile and Figures 9b and 9c show how fastening means can be distributed along two side of the display tile. Figure 10 shows the relative positions of the side that are identified as " top", " bottom" , "left" and "right". Figure 11 shows how spacers can be used to help with the alignment of display tiles. This is not part of the claimed invention. Figure 12 shows examples of parameters than can be used to evaluate the alignment of a display tile with a single adjacent display tile. This is not part of the claimed invention. Figure 13 shows examples of parameters than can be used to evaluate the alignment of a display tile with two adjacent display tiles. This is not part of the claimed invention. Definitions and acronyms

[0017] Display Element. An element of a display may be emissive, i.e. light is emitted from a front surface. The emission can be the result of activating light sources located in the display or the display can be transparent and light from a light source may be transmitted through the display before being emitted from the front surface of the display. Examples of emissive display elements are LED, OLED, plasma display, backlit liquid crystal display or light valve or a reflective liquid crystal display or light valve, etc.

[0018] Examples of reflective display elements are front lit liquid crystal light valve.

[0019] A Pixel is a picture element being an addressable unit, a plurality of which provides the capacity of a display tile or a display to display an arbitrary image.

[0020] A Display Tile has a front side or surface and a back side or surface. The front and back side are first and second major surfaces as these are the largest. The front side is the side which has light emitting pixels. The display tile has lateral sides or edges.

[0021] If a display tile is rectangular in shape, then there are four lateral sides or edges. Pairs of lateral sides oppose each other and are parallel to each other. A lateral side or edge is perpendicular to the adjoining lateral side or edge.

[0022] LED. Light Emitting Diode.

[0023] OLED. Organic light emitting diode.

[0024] Nominal. According to plans, as expected. Relating to a designated or theoretical size. Permanent joint can only be separated by causing damage to the materials used in the joint. A permanent joint is usually designed to be a joint where it is unlikely that the joint will be dismantled under any servicing situation.

[0025] Semi-permanent joint: can be dismantled at least on a limited number of occasions, but may result in loss or damage to the fastening system and / or material included within the joint. Separation may require an additional process, for example plastic deformation. A semi-permanent joint can be used when disassembly is not performed as part of regular servicing, but for specific reasons.

[0026] Non-permanent joint: can be separated without special measures or damage to the fastening system and / or materials included within the joint. A non-permanent joint is suited to situations where regular dismantling is required, for example for regular maintenance.

[0027] Temporary joint: can be assembled and disassembled easily. An example is a magnet and a ferromagnetic material such as a steel sheet, hooks and loops such as Velcro ™< , hook and eye latch, as well as a pin and a hole for the pin or similar. Hook-and-loop fasteners, hook-and-pile fasteners or touch fasteners comprise two components: typically, two fabric strips which have a first component with tiny hooks, and a second component with small loops. Hooks and loops can be made from a plastic material. When the two are pressed together the hooks catch in the loops and the two pieces fasten or bind temporarily.

[0028] A counterbore is a cylindrical flat-bottomed hole allowing entry of a matched head of a bolt.

[0029] A countersink is a cone-shaped hole allowing a matched head of a bolt.Detailed description of embodiments

[0030] In a first embodiment, an intermediary support structure or element is used to fasten a display tile to a support structure.

[0031] The intermediary support element supports a single tile. This allows each tile to be handled separately from each other in a tiled display. For example, it allows to move and / or remove one display tile while leaving the other display tiles in their position. The intermediary support element and its associated tile (usually a single tile) forms a "module". The support element is intermediary because it lies between the display tile and a support structure such as a frame or wall. The support structure supports multiple display tiles to form a tiled display. It is an advantage of embodiments of the present invention to be able to align adjacent display tiles to a high degree of precision and yet allow the support structure to be affected by tolerances worse than the required precision for the alignment. For instance, in one embodiment, the support structure can be a metallic plate as illustrated on Figure 4. The metallic plate 400 has openings 401, 402, 403, for example at regular intervals. The openings 401, 402, 403 are for receiving fasteners or fastening means, like for example, permanent or semi-permanent joints such as bolts to fasten display tiles (footprint 404 indicates the position of a still to be fastened display tile) to the support structure or more precisely, as will be described later, to fasten an intermediary structure, said intermediary structure being able to carry a display tile. The tile and its associated intermediary structure form a module, whereby there is preferably only one tile in a module. The position of the openings like 401, 402, 403 ... is affected by (determined by) tolerances that can be worse than the tolerance or precision required for the relative position of adjacent display tiles.

[0032] In any of the embodiments, the metal plate 400 can have stiffening means not shown (e.g. corrugations, tubes fastened to the metal plate, etc.) as well as additional fastening means (e.g. for fastening the metal plate to a wall or support trusses) not shown on Figure 4. The material with which the metal plate is made, can be a galvanized sheet, for example Zincor. A Zincor plate is an electrolytically galvanized steel sheet. The zinc coating can have a thickness of 2.5 microns. In most cases, DC01 steel type is used as the base material.

[0033] As will be described below, the intermediary support element solves several problems that affects high resolution tiled displays for which the seam (the distance between adjacent display tiles) is typically smaller than 1.2 mm and does not allow to access fastening means through the seam as the gap is too small. The use of an intermediary support structure allows for a greater freedom in selection of functionalities. It is convenient to access a tile from the display or front side (display side) of the tile which makes access easier when the tile is located at a significant height for example.

[0034] Figure 5 shows an example of intermediary support element 500 according to an embodiment of the present invention. This allows the fastening means of the first tile 801 to be hidden while the fastening means of the fourth tile 804 are accessible. This allows scalability.

[0035] The intermediary support element 500 has first fastening means for fastening to a support structure 400. The first fastening means 504A, 504B and 504C can include, for example, openings. Each of these openings can be located at one extremity of a Y-shaped (for example with legs 500A, 500B and 500C) or T-shaped device. fasteners such as bolts (not shown) can / will go through each opening and a corresponding opening, e.g. 401, 402, 403, respectively, in the support structure 400. In the examples of Figures 4 and 5 : a first elongate fastener, which will form a semi-permanent joint or a non-permanent joint such as with a bolt, can go through an opening of a first fastening means 504A and opening 401, a second elongate fastener which will form a semi-permanent joint or a non-permanent joint, such as with a bolt, can go through an opening of a first fastening means 504B and opening 402 and a third elongate fastener which will form a semi-permanent joint or a non-permanent joint, such as with a bolt, which can go through an opening of a first fastening means 504C and opening 403. The intermediary support element 500 has coupling means or fastening means for coupling or fastening to a display tile, e.g. with a non-permanent joint, for example to one display tile. The coupling or fastening means can be for example holes 501, 502, 503 that can mate with protrusions such as pins on the display tile. Alternatively or additionally, the coupling or fastening means can be protrusions such as e.g. pins that can mate with or enter holes on the display tile. A footprint 404 of the display tile that will be coupled to the intermediary support structure 500 is indicated on Figure 4.

[0036] The intermediary support element can be made, for instance, of Sheet-metal aluminium (e.g. EN_AW-5052_ALMG2_5_H32). Other examples of material are injection moulding aluminium (e.g. EN_AC-42000_ALSI7MG_F) or injection moulding glass reinforced plastic (e.g. PPS).

[0037] In another embodiment, another second fastening means 505A, 505B and 505C can be used for manipulating the display tile without risk of damaging the display surface of the display tile coupled to the intermediary support structure 500. Second fastening means 505A, 505B and 505C can comprise holes each located on one of the three extremities of the T or Y-shaped device as illustrated on Figure 5.

[0038] Alternatively, only two second fastening means are used: for instance 505A and 505C.

[0039] Figure 6 illustrates in a perspective view how the intermediary support element 500, e.g. in the form of the T- or Y-shaped device, is coupled to a display tile according to an embodiment of the present invention.

[0040] The display tile 600 has a first surface 601 that is a front surface or display surface. The first surface 601 is the surface on which display elements are visible. The display elements can be protected by a coating like, for instance, an anti-reflection coating. Such coating can, all too often, easily be scratched.

[0041] The display elements can be light sources such as, for example, Light Emitting Diodes or Organic Light Emitting Diodes. A display tile comprises an array of N x M light emitters such as LEDs or OLEDs. In the following, only LEDs will be mentioned, but each such mentioning includes the same disclosure with OLEDs and each such embodiment being herewith included in this disclosure. The array can be an array of sub-arrays with n x m LED where n < N and m < M. A sub-array of n x m LEDs can be mounted on a printed circuit board to form a so-called stamp. Two or more stamps are assembled on a substrate of the display tile 500 to form an array of N x M LED.

[0042] The display tile has a second surface 602 that is a back surface. The back surface 602 can have fasteners such as fastening means to be fastened to the intermediary support element 500. The fastening means form a semi-permanent or non-permanent joint. The fastener or fastening means can be pins and / or holes that will mate with corresponding holes and / or pins on the intermediary support element 500. On Figure 5, holes 501, 502 and 503 are drawn as illustrative examples. Such holes 501, 502 and 503, when the intermediary support element 500 is installed (as shown in Figure 6), do not or do not need to extend outside of the perimeter or footprint of the display tile. Holes of the first fastening means 504A, 504B, 504C and holes of the second fastening means 505A, 505B, 505C do extend outside of the perimeter or footprint of the display tile (as shown in Figure 6). The position of the holes of the first fastening means 504A, 504B, 504C and corresponding holes of the second fastening means 505A, 505B, 505C, respectively, may be as shown as an example in Figure 5 or, alternatively, as shown as another example in Figure 6.

[0043] Alternatively, the intermediary support element 500 can be screwed and / or glued to the back surface 602 of the display tile 600. In yet another alternative embodiment, the intermediary support element 500 can be integral to and with the display tile 600.

[0044] Embodiments of the invention for which the intermediary support element 500 is not an integral part of the display tile 600, have an advantage. Once a tiled display has been assembled, it is then possible to remove a display tile in particular while leaving the corresponding intermediary support element fastened to the support structure and replace the display tile by another display tile, for example, for repair.

[0045] Removing the display tile, while leaving the intermediary support element, can be done in different ways. In a first example, if the seam is large enough, a hook like structure can be inserted to exert a force on the display tile in a direction normal to the display surface (along Z-direction) and "rip" the display tile apart from the intermediary support element.

[0046] If the seam is not large enough and / or if the risk of damaging a neighboring display tile is deemed too high, it is possible to disengage display tiles from their respective intermediary support element in the reverse order with respect to how they were first tiled, until one reaches the display tile that must be replaced. Once that tile has been replaced, the tiles that were removed are fastened again to their respective intermediary support elements. No new alignment needs to be performed, since the intermediary support elements remained fastened to the support structure and since these intermediary support elements compensate for the tolerances affecting the support structure. Once the pins and / or holes of the intermediary support elements 500 and the corresponding holes and / or pins on the back surface 602 are mated, the display tile and the intermediary support elements 500 behave like a solid body, i.e. they form a module.

[0047] The intermediary support element 500 and its display tile can be fastened to the support structure. Fastening to the support structure can be done, for instance, by means of suitable fasteners or fastening means, for example, a semi-permanent or non-permanent joint such as with bolts inserted through the openings of first fastening means 504A, 504B and 504C of the element 500, one bolt being inserted through one opening, and the corresponding openings 401, 402 and 403 of the support structure 400.

[0048] Figure 7a shows a top and side view of an opening like an opening of first fastening means 504A, 504B or 504C. For example, the opening of the first fastening means 504A has a diameter D1 that is larger than the diameter of the opening 401 in the support structure 400.

[0049] A module comprising a display tile is preferably made as separate parts. This is to be able to disassemble a module or a display tile in servicing or maintenance mode, without having to remove the modules or display tile next to it. To achieve this, a module or display tile can be released from its intermediary structure 500, while leaving the intermediary structure 500 mounted.

[0050] This difference is useful to compensate for tolerances affecting the support structure (in particular the position of the openings 401, 402, 403, etc.) and to allow for a nominal alignment of the display tiles. This compensation for tolerances is illustrated in figures 7a and 7b. Even if the opening 401 and the opening of first fastening means 504A (504B, 504C) are not perfectly aligned, a bolt 700 can still be inserted through the opening of first fastening means 504A (504B, 504C) in part 504, which is a fixing part in the intermediary structure 500 and which is counterbored or countersunk, and the opening 401 in the support structure 400. The diameter of the head 701 of the bolt 700 is larger than the diameter D1 of the opening of first fastening means 504A (504B, 504C). Alternatively, a washer 702 with an outside diameter larger than D1 can be used. The diameter of the head 701 and / or of the washer 702 is smaller than a diameter D2 of the outer diameter of fixing part 504.

[0051] The intermediary support element 500 can be partially supported by the support structure 400 during assembly by means of a temporary joint as can be provided by magnets before being fastened in place with bolts. The magnets can be glued or screwed to the intermediary support element 500. An advantage is that even while the weight of the display tile is supported by the support structure 400, it is possible to glide the intermediary support element 500 and the display tile attached to it, into position. This is not part of the claimed invention.

[0052] Magnets are preferably firmly mounted on the module and are attracted magnetically to the support structure which contains ferromagnetic material. The Y- or T-shape is located in between. To form joints, the magnets should be attracted to ferromagnetic material such as steel. The module is attracted magnetically in the Z-direction, e.g. with force of approximately 10 kg to the Zincor plate and can slide over the plate with force of approximately 4 kg. If frictional forces need to be reduced, this can be done with suitable coatings such as PTFE. Indeed, it should be easy to slide during alignment and strong enough to stay in place in Z-direction. In the XY plane, the module remains in place by securing the intermediary support element 500.

[0053] An example of a magnet that can be used, is a Neodymium (NdFeB) pot magnet sold by Webcraft GmbH (Industriepark 206 78244 Gottmadingen, Germany), with properties as indicated below: Article ID: CSN-10 EAN 7640155431576 Material NdFeB Pot diameter D 10 mm Total height H 4,5 mm Borehole d1 3 mm Countersinking d2 4,8 mm Countersinking t 0,9 mm Tolerance + / - 0,1 mm Coating Nickel-plated (Ni-Cu-Ni) Steel Q235 (China) Magnetisation N38 Strength approx. 1,3 kg (approx. 12,7 N) Max. working temperature 80°C Weight 2,0000 g

[0054] A graphic of the force (expressed in kilogram) between the magnet and a sheet of steel or iron in function of the distance between the sheet and the magnet is given in https: / / www.supermagnete.be / eng / pot-magnets-with-countersunk-borehole / countersunk-pot-magnet-10mm_CSN-10. This is representative of the force exerted between such a magnet and the support structure 400. This magnet in a steel pot has a countersunk borehole and can be fastened with a countersunk screw. It is suitable for mounting solutions in the shopfitting and lighting industries as well as for household use.

[0055] Using several magnets fastened to the intermediary support element 500 that support a display tile, an attractive force of + / - 100 N keeps the intermediary support element pressed against the support structure 400 in Zincor (the intermediary support element 500 is "sandwiched" between the magnets and the support structure 400). With typical materials used for the intermediary support element 500, the friction forces that oppose or restrict movement of the intermediary support element 500 in the plane of the support structure 400, are in the range of 20 to 50 N which is well within the range of forces that a manipulator (whether human or robot) can exert without problem. Once the intermediary support element 500 and the associated display tile are at their nominal position, bolts, like bolt 700, are used to fasten the intermediary support element 500 and the associated display tile to the support structure.

[0056] Alternatively or in combination with magnets on the element 500, magnets (like 603) can be distributed across the back surface 602 of the display tile 600. As in the example of Figure 6, magnets (like 603) are distributed along the edges of the back surface 602. Referring to Figure 8a, a first tile 801 is fastened to the support structure 400 by means of its associated intermediary support structure and fastening means 8014A, 8014B and 8014C. The fastening means 8014A, 8014B and 8014C can be part of a T- or Y-shaped device like the one illustrated on Figure 5. Each of the fastening means 8014A, 8014B and 8014C can be located on one extremity of the three extremities of the T- or Y-shaped device.

[0057] A second tile 802 is then placed next to the first tile. The tile 802 is placed, for example, to the right of tile 801. When the second tile 802 is in its nominal position, the fastening means 8014C associated with tile 801 is under the tile 802, but the fastening means 8024A, 8024B and 8024C associated with the tile 802 are still accessible to introduce a bolt and fasten the tile 802 to the support structure 400. This is illustrated on Figure 8b. The openings in the support structure 400 to receive bolts are not shown.

[0058] A third tile 803 is then placed next to the second tile 802. In the example of Figure 8c, the tile 803 is placed to the right of tile 802. When the third tile 803 is in its nominal position, the fastening means 8024C associated with tile 802 is under the tile 803 but the fastening means 8034A, 8034B and 8034C associated with the tile 803 are still accessible to introduce a bolt and fasten the tile 803 to the support structure 400.

[0059] A fourth tile 804 can be placed above the first tile 801 as illustrated on Figure 8d. When the fourth tile 804 is in its nominal position, the fastening means 8014A and 8014B are under the fourth tile 804 but the fastening means 8044A, 8044B and 8044C associated with the fourth tile 804 are still accessible to introduce bolts and fasten the tile 804 to the support structure. This allows the fastening means of the first tile 801 to be hidden while the fastening means of the fourth tile 804 are accessible. This allows scalability.

[0060] A fifth tile 805 can be placed to the right of the fourth tile 804 and above the second tile 802 as illustrated on Figure 8e. When the fifth tile 805 is in its nominal position, the fastening means 8044C associated with the fourth tile 804 and the fastening means 8024A and 8024B associated with the second tile 802 are under the fifth tile 805, but the fastening means 8054A, 8054B and 8054C associated with the fifth tile 805 are still accessible and the fifth tile 805 can be fastened to the support structure 400. This allows scalability. This illustrated on Figure 8e.

[0061] The assembly of the tiled display can be pursued by adding tiles. In this example, the fastening means associated with a display tile are distributed on its top side and right side and, therefore, the assembly is done by assembling tiles from above and / or the right of display tiles already fastened to the support structure.

[0062] Disassembling the tiled display can be done, in the example just given, from the top right corner and will be done towards the left and the bottom side of the assembly, one row at a time.

[0063] It is an advantage of this embodiment of the invention that no complex mechanism is required to access the fastening means during assembly of the tiled display from a front surface of the tiled display device, even though the fastening means are larger than the distance between two adjacent display tiles. Figure 8f shows a cross section of the tiled display along a direction parallel to the axis Y of the tiled display that shows the position and dimensions of the fastening means, like 8024A, relative to the footprint F of the display tile 802 and the seam S between the display tiles 802 and 805. Figure 8f emphasizes the fact that the fastening means 8024A: Are outside of the footprint F of the display tile 802; and Cannot be accessed through the seam S that exists between the adjacent display tiles 802 and 805.

[0064] Accessing the fastening means 8024A from a front side of the display is done either before the adjacent display tile 805 is fastened to the support structure 400 or after the display tile has been removed.

[0065] Alternatively, a defective display tile 600 can be removed from its associated intermediary support element 500 by means of one or more actuators in the display tile and / or in the intermediary support structure 500. The one or more actuators can be controlled by means of the same interface that is used to transmit data and control signals to a display tile or by separate means: using, for example, a wireless communication system such as an NFC connection, a Bluetooth connection, WiFi connection or a simple FM signal or a magnetic signal, positioning a magnet at a specific place. For instance, if a pin and hole combination(s) is used to attach the display tile 600 to the intermediate support structure 500, a linear actuator at the back of the display tile can, when activated, trigger the release of the pin and hole combination(s). In that case, all the other display tiles and the corresponding intermediary support element remain in place. The position of the new display tile replacing the defective display tile is already determined by the pin and hole combination(s) used to fasten the new display tile to the intermediary support structure.

[0066] The same advantages as described above can be obtained if the fastening means are distributed along a single side of the display tile as illustrated on Figures 9a, 9b, 9c and 9d.

[0067] A display tile can be rectangular, for example an oblong or a square. The fastening means used to fasten the display tile to the support structure are either on a single side of the display tile or are distributed along two abutting sides. If two abutting sides are used, they are for instance: (left, top), (top, right) as in the examples of Figures 8a to 8e, (right, bottom) and (bottom, left). The relative positions of the top, right, bottom and left sides are seen on Figure 10.

[0068] The alignment of adjacent display tiles can be done for example with the help of a spacer as illustrated on Figure 11, not part of the claimed invention.

[0069] In its simplest form a spacer like 114a and 114b can be made of, for example, hard rubber with a thickness equal to the nominal seam between adjacent display tiles 112 and 113 and between adjacent display tiles 111 and 113. The spacers 114a and 114b can be attached to each other and form a right angle. The thickness Th of the spacer is equal to the nominal distance between adjacent display tiles.

[0070] To manipulate a display tile without having to contact its display surface, a tool can be fastened to the intermediary support structure by means of second fastening means like 1105A, 1105B, 1105C on Figure 11 and 505A, 505B, 505C on figure 5. The second fastening means 1105A, 1105B, 1105C shown on Figure 11 and second fastening means 505A, 505B, 505C on Figure 5 or Figure 6 can be part of a Y-shaped structure which can include means for fastening to a support structure, namely, for example, openings of first fastening means 504A, 504B and 504C and first fastening means 1104A, 1104B and 1104C.

[0071] The fastening means for fastening to the tool can be distributed along the same side or sides as the fastening means for fastening to the support structure. The number and disposition of fastening means for fastening to the tool can be identical to the number and disposition of fastening means for fastening to the support structure as illustrated on e.g. Figures 5 (and 11 which is not part of the invention).

[0072] The tool can be mere handles that allow manipulation of the display tile by a human agent without contact with the display surface. The fact that the tool is fastened to the intermediary support element and the display tile at the same positions as the fastening means for fastening to the support structure mean that the display tile can be positioned and fastened to the support structure at its nominal position without impediment by the tool, even if the dimensions of the fastening means for fastening to the tool are larger than the size of the seam.

[0073] Alternatively, the positioning of the display tiles can be automated. A display tile fastened to the tool is translated and / or rotated by means of one or more motors and the relative position of the display tile with respect to one or two adjacent tiles is monitored by one or more sensor(s).

[0074] The sensor can be an optical camera or image sensor. Alternatively, the sensor can be any sensor that can evaluate the distance between adjacent display tiles.

[0075] The distance between adjacent display tiles can be evaluated on the basis of the position of adjacent corners of adjacent display tiles.

[0076] In Figure 12, not part of the claimed invention, the alignment of display tile 121 with respect to display tile 120 can be evaluated by: The distance db between the bottom left corner 121b of display tile 121 and the bottom right corner 120b of display tile 120; and The distance da between the top left corner 121a of display tile 121 and the top right corner 120a of display tile 120.

[0077] If the distances da and db are different, then the right side 120R of display tile 120 cannot be parallel to the left side 121L of display tile 121. If the sides 120R and 120L are not parallel, a person or a motor can rotate the display tile by, for example, applying a torque to the display tile by the intermediary of the tool fastened to the display tile 121 by means of the fastening means 1215A, 1215B and 1215C.

[0078] If both distances da and db are equal but different from a nominal distance d0, the display tile 121 can be translated by the intermediary of the tool.

[0079] Once the two tiles are aligned, the display tile 121 can be fastened to the support structure with the fastening means 1214A, 1214B and 1214C as was described earlier.

[0080] As illustrated on Figure 13, not part of the claimed invention, the alignment of a display tile 132 can be made by monitoring the relative positions of three of its corners (132a, 132b, 132c) with respect to the corners of display tile 130 (corners 130a and 130b on the right side of the display tile 130) and / or of display tile 131 (corners 131a and 131b on the top side of display tile 131).

[0081] Similarly, to what was described with the help of Figure 12, not part of the claimed invention, the distances between corners of tile 130 and the corresponding corners of tile 132 can be evaluated as well as the distance between corners of tile 132 and the corresponding corners of tile 131: The distance db1 between the bottom left corner 132b of display tile 132 and the bottom right corner 130b of display tile 130; and The distance da1 between the top left corner 132a of display tile 132 and the top right corner 130a of display tile 130. The distance da2 between the top left corner 131a of display tile 131 and the bottom left corner 132b of display tile 132; and The distance db2 between the top right corner 131b of display tile 131 and the bottom right corner 132c of display tile 132.

[0082] If the right side 130R of display tile 130 is parallel to the left side 132L of display tile 132, then the distances da1 and db1 are equal.

[0083] If the top side 131Top of display tile 131 is parallel to the bottom side 132Bot of display tile 132, then the distances da2 and db2 are equal.

[0084] If these conditions are not met, the display tile 132 must be rotated.

[0085] Additionally, if the distances da1, da2, db1 and db2 are all equal but differ from their nominal value (the nominal value being the value when the seam is as expected), it is necessary to translate the display tile 132.

[0086] For embodiments of the invention wherein the display tile and the intermediary support structure are attached to one another by means of pins and holes, if one of the tiles is damaged, it can be extracted while leaving the intermediary support structure fastened to the support structure. The tile and the intermediary support element being manufactured with a higher precision than the support structure, a new tile can be attached to said intermediary support element without having to adjust the alignment of the tiles.

[0087] A tool can be used to manipulate a display tile without coming into contact with the display surface of the display tile, while aligning that display tile with one or more adjacent display tiles.

[0088] Trusses arching over the display surfaces can interact with the fastening means like disposed around one or two abutting sides of the display tile. Two and preferably three sensors (in particular, the sensors are image sensors) are fastened to the tool so as to have the corners of the display tile in their respective field of view. The corners to be monitored are the corners which will be closest to the display tiles already fastened to the support structure (for example 400) with which the display tile will be aligned. For instance, if the means for fastening to the support structure are along the top and right side of the display tile, the cameras have in their field of view the top left corner, the bottom left corner and the bottom right corner, respectively. In general, the corners that are used to evaluate the seam (or the distance between display tiles) are those corners that are part of the sides where there are no fastening means for fastening to the support structure and no fastening means for fastening to the tool.

[0089] The tool can be fastened to e.g. an XY + rotation motorized gantry mechanism. The motors of the gantry mechanism are controlled by controlling means (such as, for example, a microcontroller) that uses the reading of the sensors to determine how the motors must be driven to bring the readings to their desired value.

[0090] The distances da1, da2 can be derived in any way known to the art. In particular, when the sensors are cameras, ad-hoc image processing is used to determine the distances.

[0091] The distances can be derived from images taken by the image sensor by, for example, counting the number of pixels that separate specific points indicated on the surface of the display tiles in the vicinity of the corners on each display tile. For instance, one pixel at the apex of each corner can be flashed on and off to facilitate its identification (by subtracting two consecutive images and thresholding, only the flashing pixels will be left).

Claims

1. A tiled display including an intermediary support structure (500), multiple display tiles and a support structure supporting the multiple display tiles of the tiled display, characterized in that the intermediary support structure (500) is configured to carry a single display tile (600), said intermediary support structure (500) comprising coupling means (501, 502, 503) for coupling or fastening the intermediary support structure (500) to a back side (602) of the single display tile (600), the single display tile (600) having several edges and a perimeter or footprint, the intermediary support structure (500) further comprising a plurality of first fastening means (504A, 504B, 504C) for fastening the intermediary support structure (500) to the support structure, wherein - the plurality of first fastening means (504A, 504B, 504C) for fastening to the support structure is distributed along one edge of the single display tile (600) or along two adjacent edges of the single display tile (600); and - said plurality of first fastening means (504A, 504B, 504C) for fastening to the support structure is located outside of the perimeter or footprint of the single display tile (600) allowing said plurality of first fastening means (504A, 504B, 504C) to be accessed from a display side (601) of the single display tile (600), - said plurality of first fastening means (504A, 504B, 504C) extends beyond the perimeter or footprint of the single display tile by a distance D that is larger than the nominal seam between two adjacent display tiles of the tiled display.

2. A tiled display according to claim 1, wherein the intermediary support structure (500) comprises a plurality of second fastening means (505A, 505B, 505C; 1105A, 1105B, 1105C) configured to receive a tool to align the single display tile (600) with one or more display tiles of the tiled display.

3. A tiled display according to claim 2, wherein the plurality of second fastening means (505A, 505B, 505C; 1105A, 1105B, 1105C) is on the same edge or edges of the single display tile (600) as the plurality of first fastening means (504A, 504B, 504C) for fastening to the support structure.

4. A tiled display according to any of the previous claims, wherein the plurality of first fastening means (504A, 504B and 504C) include openings.

5. A tiled display according to claim 4, wherein the intermediary support structure (500) is Y-shaped or T-shaped and wherein the plurality of first fastening means (504A, 504B and 504C) comprises three openings which are each respectively located on one of the three extremities of the Y-shaped or T-shaped intermediary support structure (500).

6. A tiled display according to any of the preceding claims, wherein the coupling means (501, 502, 503) comprises pins and / or holes configured to mate with corresponding holes and / or pins on the back side (602) of the single display tile (600).

7. A tiled display according to claim 5, wherein each second fastening means of the plurality of second fastening means (505A, 505B and 505C; 1105A, 1105B, 1105C) is respectively located on one of the extremities of the Y-shaped or T-shaped intermediary support structure (500).

8. A tiled display according to claim 7, wherein the plurality of second fastening means (505A, 505B and 505C; 1105A, 1105B, 1105C) include openings.

9. A tiled display according to any of the claim 2 to 8, wherein the number and disposition of the plurality of second fastening means (505A, 505B, 505C; 1105A, 1105B, 1105C) are the same as the number and disposition of the plurality of first fastening means (504A, 504B, 504C) for fastening to the support structure.

10. A tiled display according to any of the claims 2 to 9, wherein the single display tile (600) is positioned and fastened to the support structure at its nominal position and wherein the second fastening means (505A, 505B, 505C; 1105A, 1105B, 1105C) are larger than the size of the seam between the single display tile (600; 801) and an adjacent display tile of the tiled display.