Display panel, particularly for interchangeable traffic signs

Description

[0001] Variable message signs have long been widely used in traffic management and information systems, and for decades have been implemented using LED technology. They display switchable symbols and text, as well as graphics and even video sequences, and are subject to numerous standards for use on the road network. These standards stipulate their suitability for outdoor use under all traffic, visibility, and weather conditions, especially in direct sunlight. They differ from general display boards and screens in their focused, bright light emission and mechanical resistance to damage and vandalism, as they operate relatively freely and unattended, yet are electronically monitored, and must reliably provide road users with legally relevant information.For this purpose, they use light points consisting of an LED light source with a collecting optic, which are arranged individually in symbols or in a grid as so-called pixels for graphic representations in individual light colors or controllable color values ​​for image display, emitting their light in a bundled manner towards the road users.

[0002] Since screens are often too small, far too dark, and not weatherproof for this purpose, and a protective housing impairs visibility, specialized designs have been developed for such displays, which can be divided into two groups. On the one hand, the displays form the front of a housing manufactured to a suitable size, containing all necessary components such as power supplies, wiring harnesses, control and monitoring systems, cooling, heating and ventilation, as well as mechanically adjustable mountings. The largest of these housings span all lanes of a highway, are accessible for maintenance, and are delivered by special transport. On the other hand, displays are built modularly, with each module containing all operationally necessary components and auxiliary units. The required number of modules are mounted in a grid pattern on a correspondingly large support frame.The modules are connected to each other and optionally to a connection cabinet via a multitude of cable connections and sealed plugs.

[0003] Both designs have specific advantages and disadvantages. A common feature of all designs is the display surface, which appears black when switched off and can reach a considerable temperature under direct sunlight, in addition to the comparatively lower energy consumption of the LEDs for image display. The color and brightness values ​​of the LEDs are temperature-dependent and may need to be compensated for by adjusting their control. Heat dissipation from the display surface is therefore a crucial factor, not only because of the LEDs themselves, but also because of the optics and materials used, and the resulting problems with differing thermal expansion and sealing. In particular, uneven heating in certain areas, for example due to the displayed image content, or partial shading of the display panel, must be expected, which can lead to further internal thermal stresses within the device.

[0004] A shared housing offers the significant advantage of temperature equalization between the hot, sunlit half and the cooler half, thanks to the possibility of free internal convection and external convection cooling, provided this is supported and not obstructed. An empty housing with a black front panel will never become too hot for an LED display, regardless of the sun's position. If the display is implemented in an energy-efficient and thermally effective manner, additional cooling is often unnecessary. However, if needed, significantly improved internal convection can still be achieved in such a housing with just a few fans, especially if the display surface is not vertically oriented.

[0005] A display module, on the other hand, is too small for free internal convection. The heat must be distributed via conduction and dissipated via external convection, with the functionally necessary components presenting further obstacles to heat flow. Therefore, it must be distributed and dissipated primarily via aluminum or die-cast components on a rear panel with cooling fins, or the light output may need to be reduced. Furthermore, the modules, along with the connectors and sealing costs, are relatively expensive compared to exposed and wired LED boards in a large housing. However, replacing a module in case of damage is possible even for a layperson.

[0006] The historical development of variable message signs, from individual optics with incandescent bulbs and later fiber optic bundles to individual LED optics, has always featured a metallic front panel, which is part of the device housing and has the mounting holes for the optics. A front-mounted lens for sealing has proven ineffective due to sun reflections, fogging, or damage. Therefore, designs remain in use and are even prescribed in which individual optics are inserted, pressed (as described, for example, in EP0757268A1 [Swarco]), or glued (as described in EP1593109A1 [Swarco]) into a blackened metallic front panel with punched openings; a front lens is undesirable. The fully assembled front panel is then inserted into the housing.In larger devices, the front panel must be supported against a rear support structure inside the housing using standoffs located at the intersecting corners of the LED boards. Even larger devices utilize multiple front panels glued together with metal strips, which also feature the necessary perforations or cutouts for the pre-mounted optics. Additional brackets on the front panel or the optics themselves align the LED boards with the optics and connect them to each other, as well as to power supplies and control boards, via exposed cables. The LED boards themselves are the defining, modularly designed components; like the optics and the front panel, they are directly exposed to the convection currents of the surrounding air within the housing.

[0007] This design, due to its uniform cooling, usually produces a uniformly illuminated surface, whereas modules in a housingless design often exhibit noticeable fielding of the display due to varying heat dissipation and distribution, partly because the pixel grid often cannot be precisely maintained across module boundaries. Furthermore, a common housing with a metallic front also forms a Faraday cage to protect the integrated electronics from direct lightning strikes, which can be quite relevant given typical display sizes and high, overhead mounting positions in open fields.

[0008] The visual, thermal, and electrical advantages of a metallic front panel with embedded optics are offset by significant drawbacks. Blackening can only be achieved through surface processes such as anodizing, painting, or powder coating, each of which presents specific problems like patchiness, adhesion issues, scratching, or relatively high solar reflection, as well as dimensional changes in the optic mounting holes. Punching or drilling the mounting holes leads to dents, warping, and bending of the front panel, resulting in difficult alignment. Handling panels fitted with optics is bulky and can damage them without a transport frame due to bending and warping. Automated optics assembly requires large gantry robots with additional equipment such as sorters, presses, and cameras for process monitoring, and involves considerable assembly time due to long travel distances.In addition, there is the problem of different coefficients of expansion between the metallic front panel and the sealed plastic optics, which over time can lead to stress reduction in the plastic parts, embrittlement of seals, detachment of adhesives and thus to leaks, loosening and even twisting of the optics, while permanently elastic adhesives have proven very effective for joining and sealing even large components.

[0009] There had been considerations for some time to redesign the front panel and its mounting, but this is close to a complete redesign and therefore requires at least one further impetus, such as a change in standards, a more suitable LED, an improved process, or a different manufacturer. For example, EP1227458A2 (Zelisko) describes a module made of transparent plastic containing an LED board, mounted in a grid pattern on a perforated front surface using a gasket, and featuring an internal black coating to prevent sunlight reflections. However, this module thus represents a light-permeable connection between all the optics, which is a disadvantage in terms of quality and also lacks a Faraday cage.

[0010] Modular displays on carrying frames are primarily manufactured in China, as evidenced by patents CN115394208A and CN207572010U. These are only a minor topic here, and none of them feature a Faraday cage. Patent CN 203422907 (Yaham) shows a possible configuration of one of the aforementioned modules, consisting of stacked components of approximately the same size: a front panel 200, lens assembly 600, support plate 100, and LED board 300, all within a surrounding housing 400. A gasket 500 seals the rear of the housing, protecting the LED board's electrical connections (not shown) from the elements. These modules can be arranged close together in any number. WO2014 / 0864081 (Thomas) also shows such modules, which hold light guide rows in position relative to the LEDs and exit lenses by means of support and positioning parts.Both applications fail to provide details regarding a design with an arbitrarily large housing. US2013 / 257235A1 (Haliburton) and WO2008 / 085253A1 (Daktronics) show larger modules with frontally arranged LED boards without focusing optics for known video displays. This makes it impossible to meet the very demanding lighting regulations for variable message signs, and the required energy consumption would be far too high compared to existing variable message signs.

[0011] The object of the invention was a cost-effective, modular design of the usually vertically oriented display area of ​​a variable message sign in any desired size, while maintaining a sealed individual housing and complying with all relevant mechanical, photometric, and environmental standards. A housing with a display area according to the invention is disclosed in claim 1 and is dadurch gekennzeichnet, dass The display surface of the housing includes a flat metallic carrier plate, which is stiffened by longitudinal and transverse struts and firmly connected to the housing and has an opening for each optic, as well as locating holes for positioning pins. This carrier plate is covered by preferably rectangular or square plastic tiles in which the optics are densely inserted in a grid arrangement. These tiles also have positioning pins and a surrounding edge with a contact surface as an adhesive surface, along which they are precisely and tightly glued to the carrier plate. The optics protrude inwards through the openings of the carrier plate. LED boards, fitting between the longitudinal and transverse struts, are precisely aligned with the optics from the inside via the protruding positioning pins and their locating holes, into which they shine their light and are held in place by means of spring bridges.which are locked between the longitudinal or transverse struts or attached to the positioning pins, and are pressed against the optics under defined preload.

[0012] In other words, the optics are not mounted directly in the metallic front panel. This panel merely forms a longitudinally and transversely stiffened support and mounting surface with through-holes aligned with the optics and therefore does not require a black coating. It is completely covered by rectangular or square tiles made of black plastic, in which the optics are densely mounted in a grid pattern and protrude to the rear. After adhesive is applied, these tiles are aligned with the locating pins along their surrounding edges and bonded tightly to the backing plate. Sections of the backing plate or extensions of the longitudinal struts and their corresponding locating holes lie directly under the permanently elastic adhesive and are thus also sealed.The result is a dense black front with optics whose plastic surface is geometrically designed with features such as roof prisms, bumps, microprisms, or micro-perforations to either deflect incident sunlight into irrelevant areas or reflect little to no light, absorbing it to a large extent and thus achieving a far superior result compared to a black coating. A small functional gap exists between the tiles to accommodate any differences in thermal expansion between individual tiles and the metallic backing plate.

[0013] On the inside of the mounting plate, the optics protrude through its openings. They are precisely positioned using positioning pins, which are fitted with locating holes between the longitudinal and transverse struts. To ensure that the LEDs make virtually no gap against their optics and minimize light transmission losses, springs attached to rigid bridges press against the LED board at appropriate points. These bridges are snapped into corresponding openings in the longitudinal struts or fixed to the positioning pins using washers or adhesive. Wiring can then be carried out, with cables or other components being attached along the longitudinal and transverse struts.

[0014] It is evident that the tiles, LED boards, and stiffeners of the mounting plate are all subordinate to a higher-level design grid, enabling the modular and cost-effective production of devices of any size. This design grid is based on economically and technically advantageous component sizes, the required pixel grid, and the electronic requirements of LED addressing and LED control modules. For example, a typical 20 mm pixel grid results in a module element with 8x8 = 64 optics and a size of 160x160 mm. An LED board can, however, certainly contain more LEDs, such as 128 or even 256 LEDs, thus reducing the number of cable connections. The longitudinal and transverse struts are then spaced, for example, 320 mm apart. Furthermore, the use of large and small LED boards together can be made electrically feasible.The design grid then determines the appropriate size of the entire display board. Naturally, each common pixel grid requires its own components and design grid specifications, although the optics are used in every grid.

[0015] The size and thickness of the longitudinal and transverse struts depend on static requirements, particularly the maximum wind force acting on the device. In the area of ​​the LED boards, they are only sheet metal thick, but further inwards, they can be better stabilized, for example, by means of folded edges. They feature not only positioning holes and pins, but also air vents near the mounting plate to promote internal convection. They can be placed on the mounting plate and connected with minimal distortion and stability using spot welds or laser welding. Generally, aluminum sheet is recommended for the housing and all metallic components; stainless steel may be used in chemically demanding environments, such as tunnels or near the sea.

[0016] For the enclosures themselves, a continuous C-shaped frame profile is recommended, which is mitered and welded to form a rectangular enclosure frame. The mounting plate fits precisely into this frame and is spot-welded from the inside, along with the longitudinal and transverse braces. The rear consists of one or more adjacent maintenance doors. Enclosures that can be opened as a single unit are also possible. Numerous well-tested enclosure designs, including all necessary components, are available. If the enclosure is to be painted or powder-coated, a light color should be chosen for thermal reasons, and the enclosure should be coated before the mounting plate is installed. Weld marks should be masked or subsequently sanded clean. The mounting plate should be clean and free of grease to ensure dimensional accuracy, especially for the positioning and alignment holes and for adhesive adhesion.Welding points should be positioned and executed in such a way that the coating is only affected in a small, invisible area.

[0017] With a few additional parts, modules can also be produced from the tiles, LED boards and their wiring, so that this market can also be served.

[0018] The invention will now be described in detail with reference to various illustrations and some embodiment variants.

[0019] They show FIG. 1 A und 1 B A clear view of a corner of the housing frame, including the continuous reinforced support plate, from the outside and inside. FIG. 2 A und 2 B The same applies to a carrier plate made of U-profiles. FIG. 3 a clear illustration of a tile including the optics to be fitted, FIG. 4 A the fully loaded tile from the front and FIG. 4 B from behind FIG. 5 A clear image of a tile after the application of adhesive, FIG. 6 A und 6 B A clear illustration of a fully equipped equipment corner with a continuous, reinforced support plate, both from the outside and from the inside. FIG. 7 A und 7 B The same can be clearly demonstrated with a carrier plate made of U-profiles and with alternative spring bridges, FIG. 8 A clear illustration of a modular version of the invention from the rear and FIG. 9 A horizontal section through this module. For all construction representations, tiles with 6x6 optics and a tight 12mm pixel grid were used, which allow for a clearer representation compared to actual production versions. Larger pixel grids offer more space but may require additional supports and fixings for the also larger components.

[0020] FIG. 1 A Figure 1 shows the metallic components in the area of ​​a device corner and their connection by means of indicated weld points in the construction with a continuous carrier plate of standard or necessary sheet thickness. The housing is framed by a surrounding housing profile 9 with mitered corners, which forms the opening on its front for installing the agreed display in the dimensions of the construction grid used. The carrier plate 1 is inserted into this opening, slightly recessed. It has openings 2 for each lens in the agreed pixel grid. Furthermore, it contains rectangular positioning holes 3 for fixing the stiffening longitudinal struts 5 and round locating holes 4 for later receiving the positioning pins 23 of the tiles 21.

[0021] FIG. 1 B The same corner is shown from the inside. It is assumed that the housing lies with the opening facing downwards on a welding table and that the inserted carrier plate 1 is held at this height on a base plate the thickness of the recess d. First, the longitudinal struts 5 with their extensions 5a are inserted into the positioning holes 3 and connected flush to the carrier plate 1 with spot welds 10. Then, the transverse struts 6 with their recesses 6a are inserted into the recesses 5b of the longitudinal struts 5 and welded together. The longitudinal struts 5 have large ventilation holes 8 near the carrier plate 1 and, if necessary, rectangular detent holes 7 for snapping spring bridges (46), as well as possibly further mounting holes for internal components. Finally, the carrier plate 1 itself is connected all around to the adjacent legs of the housing profile 9 by means of spot welds 10. The housing is now ready for optical and electrical assembly.Of course, the carrier plate 1 can also be welded to the longitudinal and transverse struts 5, 6 beforehand. Well-established, clean technologies such as TIG and laser welding are available, which also ensure a good electrical connection of all metallic components and can be used regardless of the material.

[0022] FIG. 2 A and 2 BWe present a design variant that is particularly recommended for larger devices. Here, the support plate is formed by perforated U-shaped support profiles 11 arranged side by side. These profiles are manufactured continuously on stamping and rolling lines and cut to length as required, or they are extruded profiles with subsequent perforation. They can also form a continuous longitudinal stiffener by offsetting them relative to one another. Their width corresponds to the construction grid, and the leg heights to the required stability. They have continuous edges 12, which are necessary to support the adhesive beads. They feature not only the optical openings 2 in the perforation grid and the locating holes 4, but also large ventilation holes 13 near the edges 12, as well as recesses 14 into which the cross braces 6 with their recesses 6a engage. This design is also held together by means of spot welds 10.If necessary, locking holes 7 can also be incorporated into the legs here, but alternative spring bridges are to be demonstrated here.

[0023] Especially with large devices, the housing must withstand considerable forces and deformations, as must its mounting, so a completely different design may be necessary, perhaps incorporating tubular steel. This could also require the construction of sections of profiles and struts. In any case, however, the display surface needs a stable, surrounding frame for protection and mounting, which often also acts as a contrast visor and whose front is then coated in black.

[0024] In FIG. 3 Figure 1 shows an enlarged view of a tile 21 with optical holes 22 for the optics and an optic 24 before insertion. Both tile 21 and optic 24 have a contact surface 25, which is shown here as a cylinder. The optic 24 has a rib 27 that projects into a groove 26 and ensures correct alignment. Before insertion, a drop of adhesive could be applied to one of the surfaces 25, or the optic could simply be pressed in with a slight oversize until it rests against the contact surface 30. Tile 21 can be warmed and optic 24 cooled to facilitate insertion. The contact surfaces 25 can also be more complex, for example, with a non-circular shape instead of a rib for orientation, or slightly conical or with multiple sections, so that the tile does not warp due to the sealing forces.The durability of the connection is achieved by using materials with the same coefficient of thermal expansion. Therefore, the tiles are preferably made of black polycarbonate and the optics of highly transparent Plexiglas. These materials have demonstrated exceptional resistance to weathering for decades, particularly to yellowing caused by UV light, and exhibit very similar thermal expansion behavior.

[0025] The front of tile 21 is provided with a structure 28 that reduces solar reflection while still allowing for easy cleaning. This structure serves to suppress sunlight falling on it for an observer of the display, in order to comply with the standard contrast requirements. Black polycarbonate, even with a rough structure, has a certain surface gloss, similar to a powder coating produced by melting, and as a flat surface, it generates excessive reflection; therefore, additional deflection and absorption structures are necessary. The structure shown here consists of roof prisms that reflect a portion of the sunlight upwards and, especially when the sun is low, almost completely absorb its rays through multiple scattering within the prism grooves.

[0026] FIG. 4 A Figure 21 clearly shows a tile 21 fully equipped with optics 24, the front of which is provided with the structure 28. It has a surrounding border 30 of constant height. Equipping the tile 21 with optics 24 is a relatively simple process to automate.

[0027] FIG. 4 B The same tile 21 is shown from the back. The surrounding edge 30 forms part of a flat mounting surface 31 for the carrier plate. It has small mounting studs 33 around its perimeter, which ensure a minimum gap for the adhesive 32. Long, slightly conical positioning pins 23 are also visible. These serve for the precise positioning of the tile on the carrier plate and are arranged asymmetrically to allow only the correct mounting position. The optics 24 are protected from damage and contamination by displaced adhesive by protective tubes 29. These tubes also provide optical shielding between the optics against stray LED light or intruding sunlight, preventing any overexposure between the pixels.The ends of the protective tubes 29 protrude slightly beyond the ends of the optics 24 and thus not only cover the gap light between the LEDs and the optic ends, but also provide additional centering of the LEDs on the optics.

[0028] FIG. 5 Figure 1 clearly shows the adhesive 32 applied to the contact surface 31 along the surrounding edge 30, representing a semi-automated assembly process. The highly viscous black polyurethane- or polymer-based adhesive remains permanently elastic after curing. Larger tiles 21 may also have additional positioning pins 23, and the contact surface 31 may also have ribs located further inwards, where adhesive is also applied to improve adhesion and prevent subsequent warping of the tile. The contact studs 33 ensure a minimum adhesive thickness, allowing the adhesive to elastically accommodate small temperature-related displacements between the tile and the backing plate.

[0029] FIG. 6 A The mounting of the display in the corner area of ​​a device with a continuous mounting plate 1 is clearly shown from the outside, Fig. 6b from the inside. An automated adhesive application is then applied. Fig. 5 Instead, only one tile 21 is inserted next to the other, determined by the positioning pins 23, which only fit into the locating holes 4 of the carrier plate 1 at the correct positions, and pressed into place, whereby the adhesive 32 is slightly displaced and the entire area under the tile 21 is sealed against the carrier plate 1 and the already existing adjacent tiles.

[0030] When applying the adhesive manually, the adhesive 32 only needs to be injected diagonally into the existing edges of the mounting position. The tile 21 is then inserted, and the adhesive 32 is compressed, thus creating a good seal. For the first tile, the adhesive 32 is injected into the edge of the housing profile 9. The remaining exposed sides of the tile are sealed by injecting the adhesive into the edges when the adjacent tile is installed. The adhesive also creeps into the gaps created by the system studs 33 and is further compressed when the adjacent tile is mounted. A functional gap 34 is created between the tiles, which accommodates the greater thermal expansion of the tiles compared to the metallic support plate 1 and prevents significant internal stresses.

[0031] For most of the tiles, a single application of adhesive at the angle of two edges is sufficient during installation. Only the last few tiles require a U-shaped application, and the very last tile requires an application along all four edges. For large tiles, additional adhesive dots can be applied within the tile itself. To secure the tiles against dents or detachment, standard retaining rings can be slid onto the positioning pins from the rear, thread-forming nuts can be screwed onto them, or the positioning pins can simply be fixed to the backing plate 1 with adhesive.

[0032] After the adhesive has cured, the LED boards 41 are inserted between the longitudinal and transverse struts 5 and 6, their locating holes 45 are placed onto the positioning pins 23, and they are pressed against the tiles 21. The LEDs 42 protrude into the protective tubes 29 until they contact the optics 24. This position is maintained by spring clips 46, which snap into the detent holes 7 of the longitudinal struts 5 and, with their springs 48, exert elastic pressure on the LED board 41 at regular intervals. This ensures that all LEDs 42 are brought into slight contact with the optics 24, despite any curvature of the LED board 41. Excessive pressure could force the optics out of the tiles or deform them before the protective tubes 29 make contact with the LED board 41. The functional components 43 and the connector 44 are arranged on the back of the LED board 41 in such a way that they do not get caught under the springs 48. Two or more connectors may also be present.

[0033] In FIG. 6 B The diagram shows how the LED board 41 is positioned approximately centrally to the ventilation holes 8. This allows convection air to reach both between the mounting plate 1 and the LED board 41, as well as its rear surface, cooling the LED board 41 and functional components 43. There is also ample space for convection air between the cross braces 6 and the LED board 41, allowing the front panel to be installed vertically or horizontally in the device. The diagram also highlights the generous space for wiring and additional components, as well as the easy accessibility. This makes it easy to replace a defective LED board 41 or any component. However, tiles 21 can also be replaced after removing the LED board 41. The surrounding functional gap 34 of the tile to be replaced is cut with a knife blade up to the carrier plate 1, this is pressed forwards with the protective tubes 29 until the adhesive 32 tears, the free space is cleaned of adhesive residue and a new tile 21 is glued in.This requires access to the device from both inside and outside.

[0034] FIG. 7 A and FIG. 7 B The illustrations clearly show the design with support profiles 11, both from the outside and inside. No longitudinal struts are required, as the stiffening is provided by the profile legs with ventilation holes 13; however, the same transverse struts 6 are necessary. The edges 12 of the support profiles 11 lie directly beneath the bonded tiles 21 and are sealed by the adhesive 32. The tiles 21 are mounted in the same way as described previously.

[0035] FIG. 7 B The LED board 41 is shown, which is mounted in the same way as before. Here, however, it is pressed against the optics 24, which are mounted on the positioning pins 23, by spring bridges 47 with springs 48 under slight preload. They can be secured with standard retaining rings, thread-forming nuts, or simply with adhesive. For this purpose, the LED board 41 also requires free space on its back side between functional components 43 and connector 44, where the springs 48 can exert pressure. The spring bridges 46 and 47 are preferably made of fiber-reinforced plastic to maintain the spring forces over the temperature range and over time. The position of the LED board 41 relative to the ventilation holes 13, which allow good airflow, is also shown here, as is the free space between the LED board 41 and the crossbars 6, and the space for wiring and additional components.Replacing LED boards and tiles 21 is done in the same way as described above.

[0036] In principle, it is possible to design a module using similar components in order to meet these market demands as well. FIG. 8 Figure 51 clearly shows the rear view of such a module with the existing LED board 41, which in this case has two connectors 44. This enables electrical "daisy-chaining," i.e., a direct cable connection from module to module without branches or distribution blocks. The modules of a device are connected to a single cable bundle in a line or bus. Of course, a single connector would also be possible, from which a cable runs from each module to a common distribution box, which also houses power supplies and control electronics.

[0037] Module 51 is provided on the rear with a cover 53, which features cooling fins 54 and connector openings 55 for access to the connectors 44. Mounting ribs 56, each with a transverse bore 57, are also shown. Adapters with seals for the cover 53, which serve as passageways for the connecting cables, are located on the support frame (not shown). Module 51 is inserted into these adapters and secured from behind via the transverse bores 67 using set screws, allowing for adjustment of its position within its range of motion. This illustration and description are for illustrative purposes only; numerous mounting options and locking connector systems are known, but these are not part of this application.

[0038] The front view in this case is a frameless arrangement of 4x2 tiles 21 with adhesive 32 applied all around and smoothed out. The carrier plate 1 is only the size of the LED board 41 and is folded over on all sides to form a stiffening frame 52, which is welded or glued at the corners and into which the cover 53 is inserted to fit precisely. Alternatively, the frame can be a separate bent component attached to the flat carrier plate 1 inserted within it by spot welds. The LED board 41 is aligned with the optics 24 via its locating holes 45 and positioning pins 23 and is held elastically on the optics 24 by means of spring clips 47, which are attached to the positioning pins 23. Frame 52 and cover 53 are sealed to each other at the end of frame 52 with adhesive 32; a circumferential adhesive tape may also be glued around as a protective cover.This module differs from competitor versions due to the inclusion of a Faraday cage.

[0039] FIG. 9Figure 51 shows a cross-section through such a module. The less favorable operating conditions are immediately apparent, as ventilation openings are not possible due to the required airtightness. This necessitates the use of spring bridges 47 mounted on the positioning pins 23. The interior does not allow convection and resembles a particularly poorly conductive triple-glazed insulating glass unit. Heat can only be dissipated by external convection, which may, of course, be sufficient for some applications or colder regions. Alternatively, forced internal convection could be implemented, for example, via compressed air hose connections. The electrical connection and control of the modules can, however, be designed identically to a version in a common housing, thus utilizing not only identical tiles 21 but also identical LED boards 41 and spring bridges 47, and thereby very efficiently covering both of the display systems described above.

[0040] Many details are presented in an advantageous design, but only as examples; numerous alternative designs are possible which do not violate the stated requirements.

Claims

1. Housing with a display surface, in particular for graphic variable message signs according to standard EN 12966 of any size, for displaying programmable content by means of full-color capable LED optics arranged in a pixel grid on the stabilized front side of the mostly metallic, sealed housing, which is accessible through rear doors or can be hinged open, characterised in that the display surface of the housing contains a metallic, flat carrier plate (1), which is stiffened by longitudinal and transverse struts (5, 6) and firmly connected to the housing and has an opening (2) for each optic (24) as well as fitting holes (4) for positioning pins (23), in that this carrier plate (1) is covered by preferably rectangular or square plastic tiles (21) in which the optics (24) are sealingly inserted in a grid arrangement, which also have positioning pins (23) and a peripheral edge (30) with a bearing surface (31) as a gluing surface, along which they are glued accurately fitting and sealingly onto the carrier plate (1), wherein the optics (24) protrude inward through the openings (2) of the carrier plate (1), and in that from the inside, LED boards (41) fitting between the longitudinal and transverse struts (5, 6) are precisely aligned with the optics (24) via the protruding positioning pins (23) and their fitting holes (45), into which they radiate their light and are pressed against the optics (24) under a defined pretension by means of spring bridges (46, 47), which are snapped in between the longitudinal or transverse struts (5, 6) or fastened to the positioning pins (23).

2. Housing with a display surface according to claim 1, characterised in that the tiles (21) completely cover the size of an LED board (41) either individually or in a grid arrangement of several tiles, and the LED boards (41) completely cover the size of the display surface either individually or in a grid arrangement of several LED boards.

3. Housing with a display surface according to claim 1 or 2, characterised in that the tiles (21) consist of black, temperature- and weather-resistant plastic, in particular polycarbonate (PC), and the optics (24) consist of highly transparent temperature- and weather-resistant plastic, in particular Plexiglas (PMMA), and the insertion of the optics (24) into the tiles (21) is carried out by pressing in and / or gluing, or preheating the tiles (21) and / or cooling the optics (24) and pressing them in as a shrink-press fit.

4. Housing with a display surface according to claim 1, 2 or 3, characterised in that the tiles (21) have on their front side roof prisms, nubs, microprisms or microholes (28), which direct sunlight into irrelevant areas, or distribute and absorb it by multiple scattering, and have a protective tube (29) formed on their rear side around each optic (24), which protects the optic during assembly against damage, dirt and displaced adhesive, acts as a further centering for the individual LEDs (42), but also prevents a crossover of both the LED light and penetrating sun rays from one optic (24) to the adjacent optics.

5. Housing with a display surface according to at least one of the claims 1 to 4, characterised in that the LED board (41) has the LEDs (42) in a grid arrangement on its front side and at least one plug (44) and functional components (43) on the rear side while keeping the pressure positions of the springs (48) clear, as well as fitting holes (45) for the positioning pins (23), and its outline is slightly smaller than the distances between the longitudinal and transverse struts (5, 6).

6. Housing with a display surface according to at least one of the claims 1 to 5, characterised in that the spring bridges (46, 47) snapped into the longitudinal struts (5) or fastened to the centering pins (23) consist of fiber-reinforced PC, polyester or resiliently formed metal and have a stable body which has elastic springs (48) evenly distributed at several points, which press the LED boards (41) against the optics (24).

7. Housing with a display surface according to at least one of the claims 1 to 6, characterised in that the carrier plate (1) has openings (2) for the optics (24) in the pixel grid, as well as positioning holes (3) for the longitudinal struts (5) regularly arranged therebetween at the grid spacing of the LED boards (41) and fitting holes (4) for their positioning pins (23) at the grid spacing of the tiles (21), and the stiffening longitudinal struts (5) engage with matching extensions (5a) into their positioning holes (3).

8. Housing with a display surface according to at least one of the claims 1 to 6, characterised in that the carrier plate (1) is formed by lining up carrier profiles (11) perforated in the optic grid in the grid width of the LED boards (41), wherein their legs function as stiffening longitudinal struts and the edges (12) form a continuous web to support the adhesive (32) subsequently overlying them.

9. Housing with a display surface according to at least one of the claims 1 to 8, characterised in that at the grid spacing of the LED boards (41), transverse struts (6) are inserted in slight overlap with the longitudinal struts (5) by means of reciprocal recesses (5b, 6a) for exact positioning.

10. Housing with a display surface according to at least one of the claims 1 to 9, characterised in that the inserted longitudinal struts (5) or the legs of the carrier profiles (11) have large ventilation holes (8) near the carrier plate (1) and the transverse struts (6) have a large distance to the carrier plate (1) due to the slight overlap with the longitudinal struts (5), in order to achieve good air circulation along the carrier plate (1) and the LED boards (41) during both horizontal and vertical mounting.

11. Housing with a display surface according to at least one of the claims 1 to 10, characterised in that the carrier plate (1), carrier profiles (11), longitudinal and transverse struts (5, 6) and the housing are made of aluminum, or of stainless steel in aggressive environments, wherein only the housing is painted or powder-coated and the carrier plate (1) and carrier profiles (11) together with stiffeners are bare.

12. Housing with a display surface according to at least one of the claims 1 to 11, characterised in that the cohesion of all metallic components of the display surface together with their fixation in the housing and necessary splices of the carrier plates (1) or the longitudinal and transverse struts (5, 6) is carried out by setting sufficient welding spots (10) with low distortion and / or by means of laser welding, wherein the housing can advantageously already be powder-coated or painted and its welding positions were preferably covered or were ground bare after coating.

13. Housing with a display surface according to at least one of the claims 1 to 12, characterised in that for mounting the tiles (21) a black, weatherproof, permanently elastic and highly viscous adhesive (32), preferably on a polyurethane or polymer basis, is introduced in the form of an adhesive bead into the fillets of the connection sides for the tile (21) to be inserted, preferably by hand, or the adhesive (32) is applied circumferentially with automation support directly onto the contact surface (31) along the edge (30) of the tile (21) prior to insertion.

14. Housing with a display surface according to at least one of the claims 1 to 13, characterised in that the positioning holes (3) for the longitudinal struts (5) and the connecting fillet of the carrier plate (1) to the housing profile (9), as well as in particular splice joints of the carrier plates (1) or carrier profiles (11) in large devices, come to lie exactly under the adhesive beads of the tiles (21) and are sealed by them.

15. Housing with a display surface according to at least one of the claims 1 to 14, characterised in that it only has the size of an LED board (41), the carrier plate (1) has a frame (52) and is fully equipped with tiles (21), the LED board (41) is pressed on with spring bridges (47) fastened to the positioning pins (23) and is covered from behind by a cover (53) with cooling fins (54) and fixed and sealed circumferentially with adhesive (32), which also has plug connections (55) that can be made watertight, adjustable and lockable, which preferably also serve directly as fasteners, and thus forms an exchangeable module (51) for modularly designed displays of any size on a suitable support frame with wiring prepared for this purpose.

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