DE20311142U1 - Multilayer sheet for use in keyboards and displays has front layer with raised sections which have coating of solvent-free, low viscosity polymer or polyurethane on reverse side, below which LEDs are fitted - Google Patents

Abstract

Multilayer sheet has a front layer (1) with raised sections (2). These have a coating (3) of solvent-free, low viscosity transparent or colored polymer and/or polyurethane on the reverse side. Light emitting diodes (LED) (15) and optical fibers (17) are fitted between the front layer and a printed backing sheet (11).

Description

Richard Wöhr GmbH

Graefenau 58 - 60

75339 Hofen

Full-surface and/or partially segmented 3D designed multilayer film with light guide chamber for point and/or area illumination for operating and/or design surfaces

The invention relates to a full-surface and/or partially segmented 3D-designed multilayer film with a light guide chamber for point and/or area illumination for operating and/or design surfaces for film-covered keyboards and/or membrane keyboards and/or displays and/or front panels, wherein the 3D design is achieved by integrating elastic caps and/or filling in domes in the elevations of the covering film, wherein the elevations are achieved by a deep-drawing process and the caps and/or domes have a spherical depression on the underside and the front film with the caps is covered by a further film and/or spacer layer, wherein this film and/or spacer layer has one and/or more LEDs in the area of the point and/or area illumination and the area around the LEDs is designed as a flat and/or recessed reflector surface.

Previously known front and/or design foils for foil-covered keyboards and/or membrane keyboards and/or displays and/or are flat and/or slightly embossed. This means that blind operation of the foil-covered keyboards and/or membrane keyboards is not possible, and no raised logo or similar is possible on front panels. In addition, it is very difficult to achieve surface illumination with these keyboards.

DE 297 03 194.5 describes membrane keyboards with domes made of polyurethane mass, whereby the domes are glued to the membrane or cast directly onto it. However, these domes do not hold permanently and come off when solvents are used. In addition, the interfaces are susceptible to dirt. Surface illumination is not possible.

Furthermore, full-surface and/or partially segmented 3D-coated films for operating and/or design surfaces are known, in which the coating is based on polymers with thioether structural units and the mechanical properties of the coating can be varied from soft elastic to hard by structural variations of the starting components and/or their molar ratios as well as the hardening, depending on the requirements of the respective application, so that transparent, soft elastic to hard, protective and/or decorative 3D coatings are produced, with the film being coated over the entire surface and/or only in certain predefined segments. The disadvantage of this solution is that, on the one hand, edge embossing is required and, on the other hand, because the coating is applied on the outside, the coating can be removed by solvents or by mechanical processes. In addition, the interfaces are susceptible to dirt.

DE 298 10 862 U1 describes a method for deep-drawing films made of thermoplastic or cold-stretchable plastic. The decorative film is embossed and a plastic inlay is inserted into the embossing during the embossing process, which results in better load distribution on the snap-action disk. The disadvantage of this solution is that the base of the plastic inlay is flat and therefore does not achieve good tactile behavior and that the key stroke is not mechanically limited by the plastic inlay. In the worst case, the snap-action disk can be destroyed.

DE 198 51 731 C1 discloses a deep-drawing process for films made of thermoplastic or cold-stretchable plastic, in which the film is provided with fillers before deep-drawing at the points where the deep-drawing profiles are produced in the subsequent deep-drawing process, the contours and profile thicknesses of which are each designed and aligned approximately to match the contours and/or profile depths of the deep-drawing cavities. The disadvantage of this process is that, since it is a negative molding process, the film is stretched very strongly at the edges and thus becomes very thin and can no longer be subjected to great mechanical stress, i.e. the keyboard is not very durable. A further disadvantage is that the use of dimensionally stable, non-form-fitting fillers does not achieve elastic behavior of the film and the film can easily be destroyed in the area of the edges. In addition, no lens effect and no surface illumination can be achieved.

The object of the invention is therefore to create a full-surface and/or partially segmented 3D-designed multilayer film with a light-guiding chamber for point and/or area illumination for operating and/or design surfaces of the type mentioned at the beginning, which gives the user an extremely good tactile switching feeling when pressing keys on film-covered keyboards and/or membrane keyboards and enables blind operation, in which the 3D-designed elevation is achieved by a deep-drawing and/or thermoforming process and the elevations are filled with an inlay and/or a coating, wherein the inlay and/or the coating is flat on the underside and/or has a spherical and/or conical depression and/or recesses for the LEDs and is designed to be transparent and/or translucent, so that luminous, optically magnifying displays are possible and that a covering, back-printed film is applied to the underside of the film, which has LEDs and light-guiding chamber integrated on the surface, wherein the The light guide chamber is flat and/or recessed so that both point and/or area illumination of the touch fields is possible and the surface has raised decorative logos and/or symbols. In addition, the 3D coating should be simple, reproducible and inexpensive.

These problems are solved with the full-surface and/or partially segmented 3D designed multilayer film with a light guide chamber for point and/or area illumination for operating and/or design surfaces, as set out in claim 1, in that a front and/or design film, which can consist of PVC, polyester, metallic, polycarbonate and polyurethane films, has one or more tangible full-surface and/or partially segmented 3D designed elevations in the form of domes and/or surfaces and/or logos and/or symbols, wherein these 3D designed elevations are achieved by a thermoforming process of the design and/or front film and the elevations obtained by this process are coated on the back and/or filled with inlays and the coating is carried out with a solvent-free, low-viscosity, crystal-clear and/or colored polymer coating material and/or with polyurethane and wherein the inlays and/or the coating on the underside are flat and/or have a spherical and/or conical depression and/or recesses for the LEDs and a further PVC, polyester, metallic, polycarbonate and polyurethane film and/or spacer layer is mounted on the 3D-designed film with the filled-in domes, wherein this film and/or layer is printed according to the design and has LEDs integrated in the places which have point and/or area illumination, wherein the areas around the LEDs are designed as light guide chambers with a flat and/or recessed conical and/or convex surface.

The full-surface and/or partially segmented 3D-designed multilayer film according to the invention with a light-guiding chamber for point and/or surface illumination for operating and/or design surfaces is therefore uneven and has one or more peaks and/or raised surfaces and/or volumetric shapes, i.e. outward-facing projections that are so high that they can be clearly felt. The peaks can mark places on film-covered keyboards and membrane keyboards where a key is pressed by pressing down the 3D-coated front and/or design film. The peaks on keyboards are therefore preferably arranged above the keys, which enables blind operation, which is not possible with conventional film-covered keyboards.

The 3D protective coating can also be located on other parts of the film that are not motivated by keystrokes, especially due to the possible optical effect of the 3D design and the creation of logos and symbols.

The full-surface and/or partially segmented 3D-designed film according to the invention for operating and/or design surfaces offers all the advantages of previously used films. It is characterized by good mechanical and chemical resistance, has excellent point and/or surface illumination of the touch fields, and can be used in practically all application areas of conventional front and/or design films for film-covered keyboards and/or membrane keyboards and/or displays and/or front panels.

A preferred embodiment of the full-surface and/or partially segmented 3D-designed multilayer film with light guide chamber for point and/or area illumination for operating and/or design surfaces has one and/or several 3D-designed domes on the front side, which are produced by positive molding under vacuum, whereby domes with a depth/diameter ratio of 4:1 are to be formed. These raised domes are fitted with inlays from the back, which have a spherical depression and recesses on the underside.

for LEDs. Another film with printing for the light guide chamber as well as back printing and conductively bonded LEDs is mounted on the film with the inlays, so that the inlays are integrated between the films.

The inlays are preferably made as injection-molded parts and are colorless and/or translucent. Depending on the type of lighting, they have one and/or more recesses on the underside for the LEDs.

An improvement in the tactile response is achieved by coating the raised areas from the back with a material that varies structurally from elastically soft to hard depending on the mechanical properties and adhesion, and forms a flat 3D surface with recesses in the 3D-designed areas. Because the material is soft and elastic, the deforming raised area, which generally means a mechanical weakening of the material, is not stressed when a key is pressed, so that the service life of the film is significantly extended.

An optical improvement with a magnification effect for reading the lettering on the film is achieved by creating an optical lens effect through the design of the elevation and/or domes in partially convex curves. The domes are therefore also suitable for optically supporting signal lights and control lights.

Viewing windows, for example above display panels, open up another area of application. Up to now, structured films have usually been used for full-surface and/or partially segmented 3D films for operating and/or design surfaces, which only allow a blurred view through the film in the case of displays or similar. By applying a 3D coating to the back in the form of a flat dome in the window area, crystal-clear transparency and a slight magnification effect can be achieved, which significantly improves the readability of low-contrast display elements.

Thus, in preferred embodiments, the domes are also arranged above signal lights or display elements.

Preferably, the 3D protective coating in the domes between the films is so firmly bonded that it cannot be removed from them without causing damage and consists of a solvent-free, low-viscosity, crystal-clear, polymeric coating material that enables transparent and very flexible protective coatings with a three-dimensional effect and high brilliance through UV irradiation.

The layout of the 3D-designed elevation and/or domes on the foil can be designed almost freely and can take into account both the shape of the key or the design form. For example, the layout can be circular, oval, rectangular or square with or without rounded corners or can represent symbol outlines or logo outlines and surfaces. However, all possible layouts are also conceivable here.

The invention is explained in more detail below in exemplary embodiments with reference to figures. They show:

Fig. 1 a sectional view of an embodiment of the full-surface and/or partially segmented 3D-designed multilayer film with light guide chamber for point and/or area illumination for operating and/or design surfaces

Fig. 2 a top view of the full-surface and/or partially segmented 3D designed multilayer film with light guide chamber for point and/or area illumination for operating and/or design surfaces

Fig. 3 a sectional view of an embodiment of the full-surface and/or partially segmented 3D-designed multilayer film with light guide chamber for point and/or area illumination for operating and/or design surfaces with a film-covered keyboard with snap-on disks

Figure 1 shows a section of the full-surface and/or partially segmented 3D-designed multilayer film according to the invention with a light-guiding chamber for point and/or area illumination for operating and/or design surfaces. The base film is a polyester film 1 which has a raised area 2, whereby the area of the raised area 2 in membrane keyboards and/or

foil-covered keyboards are arranged above the key. The area of the raised area 2 is filled from the back with the solvent-free, low-viscosity, crystal-clear, polymer coating material 3 and UV radiation gives it its three-dimensional effect and high brilliance. The coating has a spherical depression 16 on the underside and recesses 13 in the area of the LEDs 12. The polyester film 1 is stuck with a printed design film 11 from the underside 14, with LEDs 15 integrated into the film in the area of the point and/or surface illumination and the printing for the light guide chamber 17 based on reflector material on the top of the film 11 and the design printing on the back of the films.

Figure 2 shows a possible top view of the inventive full-surface and/or partially segmented 3D-designed multilayer film with a light guide chamber for point and/or surface illumination for operating and/or design surfaces. The elevations in the form of the domes 4 on the covering film 1 are circular in plan and in the shape of a spherical segment. The middle domes 5 on the film have a square plan with rounded corners, being flat at the top and convexly curved at the edge with a curvature of approx. 90°. The logo 5 is designed in the form of a glass.

In Figure 3, the inventive full-surface and/or partially segmented 3D-designed multilayer film with light guide chamber for point and/or area illumination for operating and/or design surfaces is shown in section as a design film with a film-covered keyboard with integrated contact-making snap disks on a carrier plate. A stable carrier plate 6 serves as the lower stabilizing element. The contact-making snap disks 7 are inserted into the recesses 8 of the spacer film 9 and fixed in position. The covering film 1 with the raised areas 2, which is filled with an inlay 16 that has recesses 17 for the LED 12 on the underside and a conical raised area 18 as a light guide chamber 19, is covered on the underside with a design film 11 printed on the back, with LEDs 12 integrated into the covering film 11 at the points to be illuminated and the covering film having a conically recessed light guide chamber and the light guide chamber being coated with a reflector print, is laminated onto the switching film 10 with the spacer film 9. The side of the covering film 1 facing the user has peaks 5, 6 on the outside.

Claims (21)

1. Full-surface and/or partially segmented 3D-designed multilayer film with a light guide chamber for point and/or area illumination for operating and/or design surfaces, characterized in that the outside of the film has a decorative 3D design, which is achieved by a deep-drawing process and/or thermoforming process of the design and/or front film and the elevation obtained by these processes is coated on the back and/or filled with inlays and the coating is carried out with a solvent-free, low-viscosity, crystal-clear and/or colored polymer coating material and/or with polyurethane and wherein the inlays and/or the coating on the underside are flat and/or have a spherical and/or conical and/or volumetric depression and/or elevation and/or recesses for the LEDs and the design and/or front film with the coated and/or equipped elevations has a covering film and/or layer which, at the points where the point and/or area illumination has one and/or more LEDs integrated and is designed in this area as a light guide chamber and/or light guide element. 2. Full-surface and/or partially segmented 3D designed multilayer film with light guide chamber for point and/or area illumination for operating and/or design surfaces according to claim 1, characterized in that polycarbonate film and/or polyester film and/or a polyurethane film are used as films. 3. Full-surface and/or partially segmented 3D-designed multilayer film with light guide chamber for point and/or area illumination for operating and/or design surfaces according to one of the preceding claims, characterized in that the multilayer film results in a compact elastic unit with point and/or area illumination of the touch field. 4. Full-surface and/or partially segmented 3D-designed multilayer film with light guide chamber for point and/or area illumination for operating and/or design surfaces according to one of the preceding claims, characterized in that the light guide chamber is produced on the covering film as a reflector print. 5. Full-surface and/or partially segmented 3D designed multilayer film with light guide chamber for point and/or area illumination for operating and/or design surfaces according to one of the preceding claims, characterized in that the light guide chamber is integrated as a recessed light guide chamber with a conical shape in the covering film. 6. Full-surface and/or partially segmented 3D designed multilayer film with point and/or area illumination for operating and/or design surfaces according to one of the preceding claims, characterized in that the design and/or front film has printing from the back and/or front side. 7. Full-surface and/or partially segmented 3D designed multilayer film with light guide chamber for point and/or area illumination for operating and/or design surfaces according to one of the preceding claims, characterized in that the film is matt structured at the factory. 8. Full-surface and/or partially segmented 3D-designed multilayer film with light guide chamber for point and/or area illumination for operating and/or design surfaces according to one of the preceding claims, characterized in that the film is selectively glossy at the factory. 9. Full-surface and/or partially segmented 3D-designed multilayer film with light guide chamber for point and/or area illumination for operating and/or design surfaces according to one of the preceding claims, characterized in that the inlays are manufactured as injection-molded parts. 10. Full-surface and/or partially segmented 3D designed multilayer film with light guide chamber for point and/or area illumination for operating and/or design surfaces according to one of the preceding claims, characterized in that the inlays on the underside have recesses and/or light guide chambers for the LEDs. 11. Full-surface and/or partially segmented 3D-designed multilayer film with light guide chamber for point and/or area illumination for operating and/or design surfaces according to one of the preceding claims, characterized in that vacuum deep drawing and/or positive molding and/or match-mold molding and/or pressure stretch molding and/or vacuum positive molding are used as the hot-forming process. 12. Full-surface and/or partially segmented 3D-designed multilayer film with light guide chamber for point and/or area illumination for operating and/or design surfaces according to one of the preceding claims, characterized in that the 3D design is implemented by elevations in the form of spherical caps and/or domes. 13. Full-surface and/or partially segmented 3D-designed multilayer film with light guide chamber for point and/or area illumination for operating and/or design surfaces according to one of the preceding claims, characterized in that the domes are arranged above the keys in membrane keyboards and/or membrane-covered keyboards. 14. Full-surface and/or partially segmented 3D-designed multilayer film with light guide chamber for point and/or area illumination for operating and/or design surfaces according to one of the preceding claims, characterized in that the domes and the front and/or design film are partially and/or completely transparent or translucent. 15. Full-surface and/or partially segmented 3D-designed multilayer film with light guide chamber for point and/or area illumination for operating and/or design surfaces according to one of the preceding claims, characterized in that the domes have optical lens effects. 16. Full-surface and/or partially segmented 3D-designed multilayer film with light guide chamber for point and/or area illumination for operating and/or design surfaces according to one of the preceding claims, characterized in that the domes are arranged above signal lights and/or LEDs. 17. Full-surface and/or partially segmented 3D-designed multilayer film with light guide chamber for point and/or area illumination for operating and/or design surfaces according to one of the preceding claims, characterized in that the domes are elastic. 18. Full-surface and/or partially segmented 3D designed multilayer film with light guide chamber for point and/or area illumination for operating and/or design surfaces according to one of the preceding claims, characterized in that the domes are circular or oval in plan and have the shape of a spherical element. 19. Full-surface and/or partially segmented 3D-designed multilayer film with light guide chamber for point and/or area illumination for operating and/or design surfaces according to one of the preceding claims, characterized in that the domes are rectangular or square in plan and are flat at the top, and have an approximately 90° curvature of convex shape at the edge. 20. Full-surface and/or partially segmented 3D-designed multilayer film with light guide chamber for point and/or area illumination for operating and/or design surfaces according to one of the preceding claims, characterized in that the domes are rounded-rectangular or rounded-square in plan and are flat at the top, and have an approximately 90° curvature of convex shape at the edge. 21. Full-surface and/or partially segmented 3D-designed multilayer film with light guide chamber for point and/or area illumination for operating and/or design surfaces according to one of the preceding claims, characterized in that the 3D design is in the form of lettering and logos with a 3-dimensional effect, whereby the shape of the logos can be freely designed.