CN111731184A

CN111731184A - Component having at least one surface that can be backlit and corresponding production method

Info

Publication number: CN111731184A
Application number: CN202010219099.XA
Authority: CN
Inventors: K.迈尔林; M.特里恩; A.阿布的拉齐兹
Original assignee: Volkswagen AG
Current assignee: Volkswagen AG
Priority date: 2019-03-25
Filing date: 2020-03-25
Publication date: 2020-10-02
Also published as: DE102019204061B4; DE102019204061A1

Abstract

The component has at least one surface that can be backlit, and the component has a flexible substrate layer, a light-guiding layer arranged on the substrate layer, and a light source for illuminating the end face of the light-guiding layer. Furthermore, a method for producing a backlit covering for a surface is proposed, which method comprises the steps of: a. providing a flexible substrate; b. the light source is arranged on a substrate, and a flexible, highly adhesive and optically transparent layer is applied to the substrate in such a way that a light exit opening of the light source is directed to an end side of the transparent layer, wherein the transparent layer has optically transparent micro-bodies.

Description

Component having at least one surface that can be backlit and corresponding production method

Technical Field

The invention relates to a component having at least one surface that can be backlit (Hinterleakbar), a flexible substrate layer, a light-conducting layer arranged on the substrate layer, and a light source for illuminating an end face of the light-conducting layer. The invention also relates to a method for producing a backlit covering (Verbledung) for a surface.

Background

Such components are known from the prior art and are used, for example, for covering switches or as push-button covers, for example, on column switches. Today's variants use light-conducting films as light-conducting layers, since they can be bent and thus deform the entire component at least within established limits. The component can thus be adapted to a defined geometry. Thus making it possible to: the illuminated surface or the illuminated symbol is arranged at the most different location, for example, the most different location of a motor vehicle, wherein the lighting device is usually a backlight (hinderleuchtonng).

A backlight is generally understood here to mean a lighting device which at least gives the impression that: the backlit surface or member appears to be self-illuminating.

In this case, light, for example of an LED, is coupled into the film applied to the substrate from the side. A pattern corresponding, for example, to the symbol to be displayed can then be embossed on the film, so that the coupled-out light is coupled out in the embossed region and the desired symbol is made visible.

Likewise, other solutions are known in which the light is not coupled into the light guide at the side, but rather the light source is arranged directly behind the symbol to be shown or behind the surface to be illuminated. DE 202017104082U 1 discloses, for example, a molded part or covering part for a vehicle interior, which has a transparent or light-scattering carrier on which a light-impermeable layer is arranged. A decorative layer and a protective layer are arranged above the light-impermeable layer, wherein the light-impermeable layer and the decorative layer are each interrupted by congruent recesses. Translucent filler material is introduced into these recesses, which filler material is matched in color to the decorative layer, so that the viewer perceives a surface that is as homogeneous as possible in the non-illuminated state. If the light source arranged behind the recesses in the viewing direction is now switched on, the light is thus transmitted through the translucent filling material and the recesses or the symbols formed by the recesses become visible. Microscopic scatterers, such as microscopic glass spheres, can be incorporated into the translucent material as a scattering aid.

The components known from the prior art are either not deformable if inflexible light-guide plates or other inflexible materials are used, or are only limitedly deformable if light-guide films are used as light-guide elements. Such films typically have the following characteristics: although these membranes can be bent around an axis and thus deformed based on a planar configuration, no other deformation around an axis different from the first axis is possible after such bending. In short, the most complex shapes that can therefore be formed with such light-guiding films are cylindrical. Only a so-called 2.5-dimensional deformation is achieved.

Disclosure of Invention

The task of the invention is therefore: this type of component is described, which can be deformed more flexibly (flexipler), wherein this deformability is to be maintained also after joining the individual layers of the component. The object of the invention is also to specify a method of this type, by means of which such a component can be produced.

This object is achieved according to the invention by a component having at least one surface that can be backlit, of the type described at the outset, which component is distinguished in that: the photoconductive layer is at least mainly composed of a highly viscous, optically transparent material and has optically transparent microbodies (Mikrok nanoppers).

The member may for example be a cover for a switch or other operating element. It can also be a planar covering of any structure, for example, within the interior of a motor vehicle. A substrate is to be understood to mean, in particular, a carrier material which can form the basis of a component. Here, they usually assume a structural task. At the same time, other functions, such as electronic circuits and for example sensors or the like, can also be fulfilled by the substrate. For example, the substrate can be a circuit board, in particular a flexible circuit board.

"layer or substrate is flexible" is to be understood in particular as: the layer or the substrate is deformable, in particular bendable. In this case, only a small elastic restoring force or no elastic restoring force is generated, so that plastic deformability is present.

The embodiment according to the invention has the following advantages: a three-dimensional reshaping of the monolithic component is now made possible, since comparatively rigid components such as plate-like light conductors or light conductor films are no longer used. Instead, a flexible, highly adhesive material is used as the light guide, which remains freely deformable even after being combined with other layers.

A highly viscous material is to be understood here to mean, in particular, a material which, in the form of a thin layer, is very little rigid and/or viscous. It therefore relates to an amorphous material which is only hardened to such an extent that it reversibly changes its shape under the action of a force, wherein the elasticity of the material is very low.

According to a preferred embodiment, the light-guiding layer consists at least predominantly of OCA glue. The OCA glue is understood here in particular to mean the so-called "Optically Clear Adhesive". Such materials are known in particular from the mobile phone industry, where they are used in order to interconnect different layers of a display device. For example, in the case of such a display device, the outermost glass layer can be fixed to the actual display device by means of OCA paste. In this case, an OCA paste is used for this purpose, in particular, in order to avoid undesirable light reflections at the boundaries of the different display device layers.

OCA glues are particularly distinguished by this: OCA glue has a high transmission, for example greater than 90%, greater than 95%, greater than 98% or greater than 99%, in particular greater than 99.5%, for light in the optically visible range, and is distinguished inter alia by: the OCA glue also remains flexible and deformable after hardening. OCA glues are furthermore generally very resistant to temperature changes, so that temperatures above 85 ℃ and below-40 ℃ for example, respectively, do not have a negative effect on the material over a period of more than 500 hours. Suitable OCA glues may have a refractive index in the range of 1.4 to 1.6, in particular in the range of 1.45 to 1.5. Furthermore, OCA glue has high adhesion and therefore high adhesive strength as well as high cohesive strength. OCA glues can be produced, for example, on the basis of acrylic (acryl) or silicon (silikon) bases and hardened by means of uv radiation, by means of visible light, high-energy radiation or in a catalytic manner.

Optically transparent micro-bodies may be at least partially embedded in and at least partially protruding from the light guiding layer on one side of the light guiding layer. Such a structure simplifies the production of the optically transparent layer, since, for example, OCA glue can be produced as a thin layer in large size (gro β format) and is provided for further use, and can be brought into the form according to the invention by subsequently loading the OCA glue with optically transparent microspheres. OCA glue is typically manufactured in a number of ways as thin layers and transported in that shape to a processing plant for reprocessing. The modification can then take place directly in the factory where the processing takes place, so that the OCA gum is pre-processed for reprocessing according to the invention. For this purpose, the OCA can be, for example, glued (bestreuen) with optically transparent micro-bodies. Likewise, the surface of the OCA glue may be in contact with the microbodies in other ways, for example the surface may be submerged in a large number of microbodies. These micelles are then attached to the OCA glue due to the adhesive properties of the OCA glue. Excess microbodies can then be removed from the OCA paste, for example by brushing, scraping or by a tumbling motion.

Depending on the embodiment, it may be advantageous to make the micro-bodies protrude from the light-guiding layer on the side facing away from the substrate layer. It may also be advantageous to have the micro-bodies protrude from the light guiding layer on the side facing the substrate layer. The surface from which the microcapsules project is at least partially passivated in view of the adhesive effect of the OCA glue, which may be advantageous but may also be disadvantageous depending on the purpose of use or the specific configuration of the component. For example, it is advantageous for a floodlight (Fl ä chenleucht) that the microcapsules are arranged in a region of the surface of the optically transparent layer facing away from the substrate.

These micro-bodies may be spheres, hollow spheres, ellipsoids or polyhedrons made of glass or plastic. The glass spheres or hollow spheres are cost-effective to produce, robust and simple to handle. But other materials, such as plastic, may be used to fabricate the microbodies as well.

In one embodiment of the invention, the microbodies form a layer which is filled as close as possible (packer) in the sense of a single layer (Monolage). The passivation effect on the adhesion of the OCA glue is maximized. At the same time, the overall scattering effect of the microbodies is increased.

It has proven expedient for the microspheres to have a diameter in the range from 50 μm to 300 μm, preferably from 100 μm to 200 μm.

Good results are likewise achieved if the light-guiding layer has a thickness of between 0.5mm and 2mm, preferably between 1mm and 1.5 mm. However, thinner layers, for example, between 0.2mm and 1mm and in particular between 0.2mm and 0.5mm in thickness are likewise possible.

According to one embodiment of the invention, the light-guiding layer is composed of a first sublayer and a second sublayer, which are separated from one another by a film, wherein only one of the sublayers has micro-bodies. Here, the film can prevent: the micro-bodies move in the light-guiding layer in an unimpeded manner and thus, for example, unintentionally sink from the surface of the light-guiding layer facing away from the substrate to the surface of the light-guiding layer facing the substrate or vice versa. This may be possible otherwise due to the viscosity of the material of the photoconductive layer. The two sublayers may be dimensioned (dimensionieren) in such a way that the total thickness of the sublayers corresponds to the aforementioned thickness of the light-guiding layer in the exemplary embodiment with only a single light-guiding layer. It is also possible for the two sublayers to have a corresponding thickness and thus for the total thickness of the light-guiding layer to be increased. The total thickness may then be up to twice the thickness previously mentioned.

It is advantageously possible for the light to be coupled in into a sublayer which does not have a microbody. After the light has been transferred (Ü bertritt) into the layer provided with the micro-bodies and before it is outcoupled from the light-guiding element, the light can then first propagate in the very same sub-layer without micro-bodies in an unimpeded manner.

As light source, LEDs, for example so-called side-emitting (Sidefire) LEDs, can be used. However, every other light source, such as a diode laser or other light source, may be used as well. Due to the high light output and the low-cost manufacturing possibilities, LEDs are currently preferred for most applications in relation to other light sources.

According to an advantageous embodiment, no micro-bodies are arranged in the area in which no light is to be coupled out. It is thus possible to implement, merely by structuring the light-conducting material, a design in which only certain regions of the surface of the component emit light toward the observer, so that, for example, illuminated symbols can be shown.

To increase the light output of the total system, the side of the substrate layer facing the light guiding layer may have reflective properties. In other words, the substrate layer may be mirrored.

The object is also achieved by a method for producing a backlit covering of a surface, comprising the following steps:

a. providing a flexible substrate;

b. disposing a light source on a substrate;

c. a flexible, highly adhesive and optically transparent layer is applied to the substrate in such a way that the light exit opening of the light source is directed toward the end side of the (hinweisen) transparent layer, wherein the transparent layer has optically transparent micro-bodies.

In this way, any surface that can be selectively backlit can be covered or covered in a simple and cost-effective manner.

The method according to the invention can be extended by the following additional steps:

d. a cover layer is applied to the optically transparent layer, wherein the cover layer is likewise optically transparent region by region and/or has a recess (Ausnehmung) region by region.

A component manufactured in such a way is obtained that it has a surface available that can be backlit and/or provided with illuminated symbols. Such a component can be an operating element or a display element, in particular in a motor vehicle.

The number of components available for use with the method according to the invention can be increased by performing a three-dimensional deformation of the surface after step c. The advantages according to the invention are fully exploited by this additional step. The backlit surface can also be deformed after manufacture or after the merging of the various layers, which creates a large number of new application possibilities.

As already described above in a similar manner, the method can be extended in such a way that a transparent layer is produced before step c.by producing a section (Ausschnitt) from a supplied, sheetlike, highly viscous, optically transparent material in bulk (platten foster range) and by applying transparent microcapsules to the section. In a simple manner, it is possible to modify the OCA glue present in a commercially available form such that it can be used according to the invention. Such OCA adhesive may also be referred to as OCA tape.

Likewise, the method according to the invention can be enhanced (fortbulin) in that an additional layer consisting of a highly adhesive optically transparent material, which does not contain transparent micro-bodies, is applied to the substrate or to the optically transparent layer before or after the application of the optically transparent layer. The additional layer can be separated from the first optically transparent layer by a film. The advantages already described above of a system of a multi-part (mehrteilig) construction with an optically transparent layer are thus obtained.

Drawings

Embodiments of the invention are further elucidated on the basis of the figures and the following description. Wherein:

fig. 1 shows a first embodiment of a component according to the invention in a sectional side view;

FIG. 2 shows a second embodiment of a component according to the invention in a sectional side view;

FIG. 3 shows a third embodiment of a component according to the invention in a sectional side view; and

fig. 4 shows a top view of an embodiment of the optically transparent layer according to the invention.

Detailed Description

Fig. 1 shows a first embodiment of a component 2 according to the invention in a sectional side view. The basis of the component 2 is formed by a substrate 4, which may be a flexible substrate. For example, the substrate 4 may be a PCB (printed circuit board), a leiterplane, or an FCB (flexible circuit board). A light source 12 is arranged on the substrate 4. The light source 12 is preferably a light emitting diode, for example a so-called side-emitting LED. At the end of the substrate 4 opposite the light source 12, a mirror element 14, for example a mirror film (spiegelfoil), is arranged. The mirror element 14 is optional and may improve the light output.

The light source 12, the substrate and the mirror element 14 form a substantially U-shaped boundary of a space in the illustrated cross section, wherein a transparent layer 8, which may consist of, for example, OCA glue, is arranged in the space. Glass beads 10 are embedded in the transparent layer 8, which glass beads are located near a surface 18 of the transparent layer 8 facing away from the substrate 4. This surface 18 is in the present case the surface from which the light from the optically transparent layer 8 injected by the light source 4 is outcoupled and thus from the monolithic component 2. This surface is also referred to as outcoupling surface 18 hereinafter.

Above in the figure, the cover 6 is arranged on a transparent layer 8. The cover 6 forms the visible side of the component 2 and closes it to the outside. In the mounted state of the component 2, the substrate is usually arranged on or connected to other components. The side of the substrate 4 facing the optically transparent layer 8 can have a reflective coating, so that the proportion of light leaving the component as desired through the outcoupling surface is also maximized in this way.

Other layers, such as films or other layers, may be disposed between the substrate 4 and the optically transparent layer 8. However, the optically transparent layer 8 can likewise be in direct contact with the substrate 4 and/or with the cover 6. Likewise, other layers, such as films, can also be arranged between the cover 6 and the optically transparent layer 8.

In the embodiment shown, the optically transparent layer 8 completely surrounds the glass spheres. It is also possible, however, for the glass spheres 10 to protrude partially or predominantly from the optically transparent layer 8. During the operating phase with the activated lighting device or backlight, the light emitted by the light source 12 is coupled into the optically transparent layer 8 via the end face 16 thereof. The light is optionally reflected at the mirror element 14 and/or at the side of the substrate 4 facing the optically transparent layer 8 and is finally scattered at the glass spheres 10 and outcoupled from the component 2 via the outcoupling surface 18. This outcoupling surface 18 or the area not covered by the cover 6 is now perceived by the viewer as luminous. In the shown cross-section, the cover 6 completely covers the outcoupling surface 18. However, it should of course be seen in the complete, three-dimensional representation or in the two-dimensional plan view of the component: the cover 6 has openings or optically transparent regions, which can show symbols, for example.

Fig. 2 shows a second exemplary embodiment of a component according to the invention in a sectional side view. Also visible are the substrate 4, the light source 12, the mirror element 14, the cover 6 and the transparent layer 8 with the glass spheres 10. The difference between the illustrated second embodiment and the first embodiment illustrated in fig. 1 is: glass spheres 10 are arranged near the surface of the transparent layer 8 facing the substrate 4. This can be achieved, for example, by the transparent layer 8, for example OCA glue, being turned over (umdrehen) before being combined when applied to the substrate 4 compared to the case shown in fig. 1.

Fig. 3 shows a third embodiment of the component according to the invention in a sectional side view. Here, it should also be observed that: a substrate 4, a light source 12, a mirror element 14, a cover 6 and a transparent layer 8 with glass spheres 10. In this exemplary embodiment, the optically transparent layer 8 is embodied in two parts. The optically transparent layer is composed of an underlying OCA layer 20 and an overlying OCA layer 22, which are in turn separated from each other by a film 24. In the embodiment shown, only the upper OCA layer 20 has glass spheres 10, while the lower OCA layer 22, by contrast, has no glass spheres 10. Depending on the viscosity of the

OCA layer

20, 22 or 8, the glass spheres 10 are movable within the

layer

20, 22 or 8. The membrane 24 constitutes a barrier between the two

adhesive layers

20 and 22, which glass spheres cannot cross the barrier and thus limit the resting place of the glass spheres 10 on the upper OCA layer 20. Alternatively, the glass spheres can also be arranged in the underlying OCA layer 22.

Fig. 4 shows a top view of an embodiment of the optically transparent layer 8 according to the invention. It will be seen that the OCA glue 8, on which the glass spheres 10 are distributed. The glass spheres 10 are filled as densely as possible in this case, so that only small gaps are present between the glass spheres 10. The glass spheres 10 are arranged here in a single layer. In other words, there is only a very small gap between the glass spheres. The majority of the glass spheres 10 are in direct contact with at least one other glass sphere. At the same time, there is little overlap between the individual glass spheres 10. In other words, in the context of production accuracy, there are no areas in which a plurality of glass spheres are arranged one above the other, where "one above the other" means here: perpendicular to the main extension direction of the outcoupling surface (hauptasdehnngsrichtung) in terms of layout or sequence.

List of reference numerals

2 members capable of backlighting

4 substrate

6 cover

8 OCA glue

10 glass bead

12 light source

14 mirror film

16 interface

18 interface

OCA layer under 20

22 of OCA layer

24 film

26 have a layer of OCA of glass beads.

Claims

1. A component (2) having at least one backlit surface, said component having a flexible substrate layer (4), a light-guiding layer (8) arranged on the substrate layer (4) and a light source (12) for illuminating an end side (16) of the light-guiding layer (8), characterized in that the light-guiding layer (8) is composed at least predominantly of a highly viscous, optically transparent material and the light-guiding layer (8) has optically transparent micro-bodies (10).

2. Component (2) according to claim 1, characterized in that the light guiding layer (8) is at least mainly composed of OCA glue (8, 20, 22).

3. A member (2) according to one of the preceding claims, characterized in that said optically transparent micro-bodies (10) are at least partially embedded in said light guiding layer (8) and at least partially protrude from said light guiding layer (8) on one side thereof.

4. Component (2) according to one of the preceding claims, characterized in that the microcapsules (10) constitute a layer which is substantially packed as densely as possible in the sense of a single layer.

5. Component (2) according to one of the preceding claims, characterized in that the microbodies (10) have a diameter in the range between 50 μm and 300 μm, preferably between 100 μm and 200 μm.

6. A structure (2) according to one of the preceding claims, characterized in that said light guiding layer (8) is composed of a first sub-layer (20) and a second sub-layer (22), said sub-layers being separated from each other by a film (24), wherein only one of said sub-layers (20, 22) has micro-bodies (10).

7. An arrangement (2) according to claim 6, characterized in that the light is incoupled into the sub-layers (20, 22) which do not have micro-bodies.

8. Component (2) according to one of the preceding claims, characterized in that no micro-bodies (10) are arranged in the region of the surface in which no light shall be outcoupled.

9. Method for producing a backlit covering for a surface, having the following steps:

a. providing a flexible substrate (4);

b. -arranging a light source (12) on the substrate (4);

c. a flexible, highly adhesive and optically transparent layer (8) is applied to the substrate (4) in such a way that the light exit openings of the light sources (12) are directed toward the end face (16) of the transparent layer (8), wherein the transparent layer (8) has optically transparent microcapsules (10).

10. The method of claim 9, wherein the three-dimensional deformation of the surface is performed after step c.