DE20308518U1 - Multi-layered design and/or front film made of plastic, comprises a filling member at the deep drawn points, and an additional film - Google Patents

Abstract

An illuminated multi-layered design and/or front film made of thermoplastic or cold stretch plastic, comprises a filling member at the deep drawn points, with contours that match those of the deep drawn cavity. The profile thickness corresponds to the profile depth and the filling member has one or more cut outs and/or light guide chambers for LED's. The member consists of transparent and/or diffuse and/or translucent material. An additional film is applied to the deformed film with the integral filling member which has one or more surface illuminated design and/or front films. The surface around the LED's is in the form of a reflector. The films consist of polycarbonate or polyester.

Description

Richard Wöhr GmbH

Graefenau 58 - 60

75339 Hofen

06.05.03

Point and/or area illuminated multilayer design and/or front foils made of thermoplastic or cold-stretchable plastic

The invention relates to a point- and/or area-illuminated multilayer design and/or front foil made of thermoplastic or cold-stretchable plastic, which is produced with the aid of a negative mold in which the foil has fillers at the points that are deep-drawn, the contours of which are approximately the same and/or the same as the contour of the deep-drawing cavities, the profile thickness of which corresponds to the thickness of the profile depth of the deep-drawing cavities, the fillers having recesses and/or light-guiding chambers for LEDs on the underside and the fillers being arranged and aligned according to the deep-drawing cavities, and a further foil is glued onto the foil, which is designed in such a way that it has, for example, a design print on the underside and has one and/or more mounted LEDs on the top, which are arranged on the point- and/or area-illuminated touch fields and protrude into the recesses of the fillers, and the fillers being made of transparent and/or diffuse and/or clear and/or made of translucent material.

DE 38 40 542 C1 and DE 37 27 926 C2 disclose deep-drawing processes for films or thin plates made of thermoplastic or cold-stretchable plastic and formed using known vacuum and compressed air processes. Deep-drawing tools with metal matrices are used for this purpose, in which the cavities forming the negative molds are either cast or machined.

DE 198 27 550 A1 describes a process for producing partially reinforced plastic components I ····

known, in which hot-formable \ ·

Reinforcing materials containing fibres with a length > 1 mm are used. These · ·..*

However, components are not used as decoration and/or front foils. *

Furthermore, deep-drawing tools for forming films are known in which the matrix consists of a *...,*

and/or several superimposed plates made of dimensionally stable plastic, in which · ·

the cavities are arranged in the form of cut-out openings. *.,*.*

The films produced using such processes are used as design and/or front films by ····,

foil-covered keyboards, whereby the deep-drawn profiles serve as positive elevations for ·,···*

the manually operated keys of the foil-covered keyboards. A disadvantage of all such _# '

manufactured films is that no surface illumination of the touch fields is possible. ·..'.'

To stabilize and better protect against these films being pushed through, there are known ways of providing the deep-drawn profiles with fillers that are subsequently cast and/or inserted into the hollow profiles after the molding process. These processes are expensive and complicated.

From DE 198 51 731 C1 a deep-drawing process is known in which the film is provided with fillers at the points where the deep-drawing profiles are produced before deep-drawing, wherein the contours and profile thicknesses of the fillers are each designed to correspond at least approximately to the contours and/or profile depths of the deep-drawing cavities into which they are sunk during the deep-drawing process.

The disadvantage of using these films on keyboards covered with film is that the function of the keys is impaired by the cast cavities and that the snap domes are not fixed in position and can be pushed through. In addition, the processes are very complex and expensive to use.

The invention is therefore based on the object of creating a method of the type mentioned at the outset with which multilayer films with hollow profiles can be produced in a simple and cost-effective manner by means of forming processes in deep drawing and adhesive processes, which do not affect the function of the keyboard when the film is used in film-covered keyboards based on snap disks.

and which ensure that point and/or area illumination of the touch fields is possible.

This object is achieved according to the invention in that the film to be deformed, before it is stretched onto the die of the deep-drawing tool, is provided with fillers at the points where the deep-drawing profiles are created, the outer contour of which corresponds approximately to the outer contour of the deep-drawing cavities and the profile thickness of which is approximately matched to the profile depth of the deep-drawing cavities, and wherein the underside of the fillers has additional recesses and/or light-guiding chambers for LEDs and the fillers are made of transparent and/or diffuse and/or clear and/or translucent material, and an additional film is applied to the film to be deformed with the integrated fillers, which film preferably has a design printed on the back and has LEDs on the top that protrude into the recesses in the fillers, and wherein the area around the LEDs is equipped as a reflector.

The main advantage of this design is that after removing the foil from the deep-drawing tool, it only needs to be cut to size and the second foil with the LEDs needs to be glued onto this foil.

It is advantageous that the fillers are firmly fixed to the film by means of an adhesive and/or glue.

It is beneficial if the filler in the upper area adjacent to the film is the same size and adapted to the shape of the deep-drawing cavities.

The design of a reflector on the lower foil in the area of the LEDs has a beneficial effect on the area lighting.

The invention is explained in more detail using some embodiments, some of which are shown schematically in the drawings. It shows:

Fig. 1: Section through a film with filler and integrated filler before deep drawing J *

Fig. 2: Section through the multilayer film with filler and covering film with integrated LEDs after deep drawing

Fig. 3: Design and/or front foil for foil-covered keyboard

Fig. 4: Filler in section with cutout for LED

Fig. 5: Section through a membrane keyboard with filling body and surface illumination of the keypad

Figure 1 shows a section through a film with filler before deep drawing. The base film made of polyester 1 has fillers 2 that are firmly fixed to the base film 1 by means of an adhesive layer 3. The outer contour of the fillers 4 is cylindrical. A recess 6 is integrated on the underside of the filler 5, the outer contour 7 of which is slightly larger than that of the LEDs 8.

Figure 2 shows a section through a multilayer film with filler and integrated recess for the LEDs after deep-drawing. The base film 1 has deep-drawing profiles 10. The filler's contour 4 is slightly smaller than the contour of the deep-drawing profiles 10. The height 11 of the filler is approximately the same as the height 12 of the deep-drawing profiles 10. The underside of the filler has recesses 6, the outer shape of which corresponds to the contour of the LEDs and is slightly larger than the shape of the LEDs. Another film is mounted on this film, which has LEDs at the area-illuminating points that protrude into the recesses of the filler and whose immediate surroundings have a reflector coating. The design is preferably printed on the back of the covering film.

Figure 3 shows the design and/or front foil for foil-covered keyboards. The foil 1 has deep-drawn profiles 10 which are raised on the foil 1 and mark locations for buttons 13. The deep-drawn profiles 10 represent elevations in the form of the domes 14 on the covering foil 1 and are circular in plan and in the shape of a spherical segment. The middle domes 15 on the foil have a square plan with rounded corners, whereby they

are flat at the top and convex at the edge with a curvature of approx. 90°. The logo 16 is designed in the form of a glass.

Figure 4 shows a filling body in section with a milled recess for LEDs. The filling body 17 has a convex surface 18 and one and/or more milled recesses 21 for LEDs on the underside.

Figure 5 shows a section through a membrane keyboard with a filler and surface illumination of the keypad. The filler 24 is designed so that it can be viewed as a key cap and has at least two recesses 25 for LEDs on the underside. A film 32 is laminated onto the covering design film 30 with the integrated key caps 24, which has LEDs at the surface-illuminated points that protrude into the recesses 21 on the underside of the key caps 24. The contact-making snap disks 29 are inserted into the recesses 25 of the spacer layer 26 and fixed in position. The covering design film 30 with the raised areas 31 is laminated onto the switching film 32 with the spacer layer 26.

Claims (10)

1. Point and/or area-illuminated multilayer design and/or front films made of thermoplastic or cold-stretchable plastic, characterized in that the film has fillers at the points that are deep-drawn, the contours of which are approximately the same and/or the same as the contour of the deep-drawn cavities, and the profile thickness of which corresponds to the profile depth of the deep-drawn cavities and which are arranged and aligned in accordance with the deep-drawn cavities, wherein the fillers have one and/or more milled recesses and/or light-guiding chambers for LEDs on their underside, and the fillers are made of transparent and/or diffuse and/or clear and/or translucent material, and wherein an additional film is applied to the deformed film with the integrated fillers, which has one and/or more LEDs on the top that protrude into the recesses in the fillers. 2. Point and/or area-illuminated multilayer design and/or front films made of thermoplastic or cold-stretchable plastic according to claim 1, characterized in that the area around the LEDs on the lower film is equipped as reflectors. 3. Point and/or area-illuminated multilayer design and/or front films made of thermoplastic or cold-stretchable plastic according to one of the preceding claims, characterized in that the recesses and/or light-guiding chambers for the LEDs are arranged in the region of the touch fields. 4. Point and/or area-illuminated multilayer design and/or front films made of thermoplastic or cold-stretchable plastic according to one of the preceding claims, characterized in that the fillers are firmly connected to one and/or both films. 5. Point and/or area-illuminated multilayer design and/or front films made of thermoplastic or cold-stretchable plastic according to one of the preceding claims, characterized in that the fillers are manufactured as injection-molded parts. 6. Point and/or area-illuminated multilayer design and/or front films made of thermoplastic or cold-stretchable plastic according to one of the preceding claims, characterized in that the filling bodies are made of sheet material. 7. Point and/or area-illuminated multilayer design and/or front films made of thermoplastic or cold-stretchable plastic according to one of the preceding claims, characterized in that the filling bodies have integrated light-guiding chambers and/or reflector surfaces. 8. Point and/or area-illuminated multilayer design and/or front films made of thermoplastic or cold-stretchable plastic according to one of the preceding claims, characterized in that the films are made of polycarbonate or polyester. 9. Point and/or area-illuminated multilayer design and/or front films made of thermoplastic or cold-stretchable plastic according to one of the preceding claims, characterized in that the film is a metal foil. 10. Point and/or area-illuminated multilayer design and/or front films made of thermoplastic or cold-stretchable plastic according to one of the preceding claims, characterized in that the LEDs emit light from the side.