DE102019204061A1 - Component with at least one backlit surface and method for producing a backlit facing of a surface - Google Patents

Abstract

A component with at least one backlit surface, with a flexible substrate layer, a light-guiding layer arranged on the substrate layer and a light source for illuminating an end face of the light-guiding layer is characterized in that the light-guiding layer consists at least predominantly of a highly viscous, optically transparent material , and that the light-conducting layer has optically transparent micro-bodies.
Furthermore, a method for producing a backlit facing of a surface is proposed, with the following steps
a. Providing a flexible substrate
b. Arranging a light source on the substrate
Application of a flexible, highly viscous and optically transparent layer on the substrate in such a way that a light exit opening of the light source points to an end face of the transparent layer, the transparent layer having optically transparent micro-bodies.

Description

The invention relates to a component with at least one backlit surface, with a flexible substrate layer, a light-guiding layer arranged on the substrate layer and a light source illuminating an end face of the light-guiding layer. The invention also relates to a method for producing a backlit facing of a surface.

Such components are known from the prior art and are used, for example, to cover switches or as key caps, for example on steering column switches. Modern variants use a light-guiding film here as the light-guiding layer, since this can be bent and thus enables the entire component to be deformed, at least within certain limits. The component can thus be adapted to a specific geometry. It is thus possible to arrange illuminated surfaces or illuminated symbols at a wide variety of locations, for example on a motor vehicle, the lighting generally being backlighting.

Backlighting is generally understood to mean lighting that at least gives the impression that the backlit surface or the backlit component would light up independently.

For this purpose, light, for example from an LED, is coupled laterally into the film that is applied to the substrate. For example, a pattern corresponding to the symbol to be displayed can then be embossed on the film, so that the light is then coupled out in the area of the embossing and the desired symbol becomes visible.

Other concepts are also known in which the light is not coupled laterally into a light guide, but a light source is arranged directly behind the symbols to be displayed or behind the surfaces to be illuminated. From the DE 20 2017 104 082 U1 For example, a molded part or trim part for a vehicle interior is known which has a transparent or light-scattering carrier on which an opaque layer is arranged. A decorative layer and a protective layer are arranged above this opaque layer, the opaque layer and the decorative layer each being interrupted by congruent cutouts. A translucent filler material is introduced into the recesses, the color of which is matched to the decorative layer, so that in the non-illuminated state a viewer perceives a largely homogeneous surface. If a light source arranged behind the cutouts in the viewing direction is now switched on, the light is thus transmitted through the translucent filler material and the cutouts or the symbol formed by the cutouts becomes visible. Microscopic scattering bodies, for example microscopic glass spheres, can be introduced 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 they are only deformable to a limited extent if light-guiding foils are used as light-guiding elements. Such films regularly have the property that, starting from a planar configuration, they can be curved around an axis and thus deformed, but no further deformation around an axis other than the first axis is possible after such a curvature. Put simply, the most complex shape that can be represented using such a light guide film is a cylinder. Only a so-called 2.5-dimensional deformation is therefore possible.

It is therefore the object of the present invention to provide a generic component which can be deformed more flexibly, the deformability also being retained after the individual layers of the component have been joined together. It is also the object of the present invention to provide a generic method with which such a component can be manufactured.

The object is achieved according to the invention by a component with at least one backlit surface of the type described above, which is characterized in that the light-guiding layer consists at least predominantly of a highly viscous, optically transparent material, and that the light-guiding layer has optically transparent micro-bodies.

The component can, for example, be a panel for a switch or other operating element. It can also be a flat paneling of any structure, for example within a motor vehicle interior. A substrate is understood to mean, in particular, a carrier material that can form a base of the component. It usually takes on structural tasks. At the same time, other functions, such as electronic circuits and, for example, sensors or the like, can also be fulfilled via the substrate. For example, the substrate can be a printed circuit board, in particular a flexible printed circuit board.

The fact that a layer or a substrate is flexible is understood in particular to mean that the layer or the substrate is deformable, in particular bendable, is. This creates only little or no elastic restoring forces, so that there is plastic deformability.

The embodiment according to the invention has the advantage that a three-dimensional post-deformation of the entire component is now possible, since a relatively rigid component such as a plate-shaped light guide or a light guide film is no longer used. Instead, a flexible, highly viscous material is used as the light guide, which remains freely deformable even after being joined to the other layers.

A highly viscous material is understood to mean, in particular, a material that, in the form of a thin layer, has very low rigidity and / or is viscous. It is therefore an amorphous material that has only hardened to such an extent that it reversibly changes its shape under the action of forces, the elasticity of the material being very low.

According to a preferred embodiment, the light-conducting layer consists at least predominantly of an OCA adhesive. An OCA adhesive is understood to mean, in particular, a so-called “optically clear adhesive”. Such materials are known in particular from the mobile phone industry, where they are used to connect different layers of a display to one another. For example, with such a display, the outermost glass layer can be attached to the actual display by means of an OCA adhesive. Here, OCA adhesives are used, among other things, to avoid unwanted light reflections at the boundaries of different display layers.

An OCA adhesive is characterized in particular by the fact that it has a high transmission for light in the optically visible range of, for example, more than 90%, more than 95%, more than 98% or more than 99%, in particular more than 99.5% , and in particular by the fact that it still remains flexible and deformable even after curing. OCA adhesives are also generally very temperature-resistant, so that temperatures above 85 ° C and below -40 ° C, for example, have no negative impact on the material for a period of more than 500 hours. A suitable OCA adhesive can have a refractive index in the range from 1.4 to 1.6, in particular in the range from 1.45 to 1.5. Furthermore, OCA adhesives have high adhesive forces and thus high adhesive strength and high cohesive strength. OCA adhesives can be made, for example, on an acrylic or silicone basis and cured by means of ultraviolet radiation, by means of visible light, high-energy radiation or catalytically.

The optically transparent micro-bodies can be at least partially embedded in the light-conducting layer and at least partially protrude from the light-conducting layer on one side thereof. Such a structure simplifies the production of the optically transparent layer, since, for example, an OCA adhesive can be produced in large format as a thin layer and made available for further use, as well as being brought into the shape according to the invention by subsequently applying the optically transparent micro-bodies. OCA adhesives are regularly produced in large quantities as thin layers and transported in this form to the processing plant for further processing. The modification to the effect that the OCA adhesive is prepared for further processing according to the invention can then take place directly in the processing company. For this purpose, the OCA adhesive can be sprinkled with the optically transparent micro-bodies, for example. Likewise, a surface of the OCA adhesive can be brought into contact with the micro-bodies in other ways, for example the surface can be immersed in a large amount of the micro-bodies. The micro-bodies then adhere to the OCA adhesive due to the adhesive properties of the adhesive. Excess micro-bodies can then, for example, be brushed off, wiped off or removed from the OCA adhesive by a tilting movement.

Depending on the embodiment, it can be advantageous if the micro-bodies protrude from the light-conducting layer on the side facing away from the substrate layer. It can also be advantageous if the micro-bodies protrude from the light-conducting layer on the side facing the substrate layer. The surface from which the micro-bodies protrude is at least partially passivated with regard to the adhesive effect of the OCA adhesive, which can be advantageous, but also disadvantageous, depending on the intended use or the specific configuration of the component. For example, it is advantageous for a surface light if the micro-bodies are arranged in the area of the surface of the optically transparent layer facing away from the substrate.

The micro-bodies can be spheres, hollow spheres, ellipsoids or polyhedra made of glass or plastic. Spheres or hollow spheres made of glass are inexpensive to manufacture, robust and easy to use. Other materials, for example plastics, are also possible for producing the micro-bodies.

In a further development of the invention, the micro-bodies form an essentially as densely packed layer as possible in the sense of a monolayer. The passivating effect on the adhesive effect of the OCA glue is thus maximized. At the same time, the overall scattering effect of the micro-bodies is increased.

It has proven to be expedient if the micro-bodies have a diameter in the range between 50 μm and 300 μm, preferably between 100 μm and 200 μm.

A good result is also achieved if the light-conducting layer has a thickness between 0.5 mm and 2 mm, preferably between 1 mm and 1.5 mm. Thinner layers, for example between 0.2 mm and 1 mm and in particular between 0.2 mm and 0.5 mm thick, are also possible.

According to a further development of the invention, the light-conducting layer consists of a first sub-layer and a second sub-layer which are separated from one another by a film, only one of the sub-layers having micro-bodies. The film can prevent the micro-bodies from moving unhindered in the light-guiding layer and thus, for example, unintentionally sink from the surface facing away from the substrate to the surface of the light-guiding layer facing the substrate, or vice versa. Otherwise, this may be possible due to the viscosity of the material of the light-conducting layer. The two sub-layers can be dimensioned in such a way that their total thickness corresponds to the previously mentioned thickness of the light-guiding layer from the exemplary embodiments with only a single light-guiding layer. It is also possible for both sub-layers to have a corresponding thickness and the total thickness of the light-conducting layer thus increases. The total thickness can then be up to twice the aforementioned thicknesses.

It is advantageously possible for the light to be coupled into the partial layer which has no micro-bodies. The light can then initially propagate unhindered in precisely that sublayer before it is decoupled from the light guide element after passing into the sublayer provided with micro-bodies.

An LED, for example a so-called sidefire LED, can be used as the light source. Any other light source, for example a diode laser or another light source, can however also be used. Due to the high luminous efficiency and the inexpensive manufacturing possibility, LEDs are currently preferred over other light sources in most applications.

According to an advantageous development, no micro-bodies are arranged in surface areas in which no light is to be coupled out. It is thus possible, by structuring the light-conducting material alone, to achieve a configuration in which only certain areas of the surface of the component emit light towards the viewer so that, for example, illuminated symbols can be displayed.

In order to increase the light yield of the overall system, the side of the substrate layer facing the light-conducting layer can have light-reflecting properties. In other words, the substrate layer can be reflective.

1. a. Bereitstellen eines flexiblen Substrats
2. b. Anordnen einer Lichtquelle auf dem Substrat
3. c. Aufbringen einer flexiblen, hochviskosen und optisch transparenten Schicht auf dem Substrat derart, dass eine Lichtaustrittsöffnung der Lichtquelle zu einer Stirnseite der transparenten Schicht hinweist, wobei die transparente Schicht optisch transparente Mikrokörper aufweist.

The object is also achieved by a method for producing a backlit facing of a surface, with the steps

1. a. Providing a flexible substrate
2. b. Arranging a light source on the substrate
3. c. Application of a flexible, highly viscous and optically transparent layer on the substrate in such a way that a light exit opening of the light source points to an end face of the transparent layer, the transparent layer having optically transparent micro-bodies.

With such a method, any surface can be clad or veneered simply and inexpensively, it being possible for the surface to be selectively backlit.

• d. Aufbringen einer Verblendungsschicht auf der optisch transparenten Schicht, wobei die Verblendungsschicht bereichsweise ebenfalls optisch transparent ist und/oder bereichsweise Ausnehmungen aufweist.

erweitert werden. Es wird so ein fertiges Bauteil erhalten, dass eine nutzbare Oberfläche aufweist, die hinterleuchtet und/oder mit beleuchteten Symbolen versehen sein kann. Ein solches Bauteil kann ein Bedienelement oder ein Anzeigeelement, insbesondere in einem Kraftfahrzeug, sein.The inventive method can by the additional step

• d. Application of a facing layer on the optically transparent layer, the facing layer also being optically transparent in some areas and / or having recesses in some areas.

be expanded. A finished component is thus obtained that has a usable surface 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 accessible to the method according to the invention can be increased by, after step c. a three-dimensional deformation of the surface is carried out. This additional step makes use of further advantages of the method according to the invention. The backlit surface can also be deformed after production or after the individual layers have been joined, which creates a multitude of new application possibilities.

As already described above in a similar form, the method can be expanded in this way that before step c. the transparent layer is produced by producing a section from a plate-shaped quantity of a highly viscous, optically transparent material provided and sprinkling it with transparent micro-bodies. It is thus possible in a simple manner to modify an OCA adhesive in the commercially available form in such a way that it can be used according to the invention. Such an OCA adhesive can also be referred to as an OCA tape.

The method according to the invention can also be developed by applying an additional layer of a highly viscous, optically transparent material that does not contain any transparent micro-bodies 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 of a system with a multi-part structure of the optically transparent layer then result, as already described above.

• 1: ein erstes Ausführungsbeispiel eines erfindungsgemäßen Bauteils in einer geschnittenen Seitenansicht,
• 2: ein zweites Ausführungsbeispiel eines erfindungsgemäßen Bauteils in einer geschnittenen Seitenansicht,
• 3: ein drittes Ausführungsbeispiel eines erfindungsgemäßen Bauteils in einer geschnittenen Seitenansicht, und
• 4: eine Draufsicht auf ein Ausführungsbeispiel einer erfindungsgemäßen optisch transparenten Schicht.

Embodiments of the invention are explained in more detail with reference to the drawings and the following description. Show it:

• 1 : a first embodiment of a component according to the invention in a sectional side view,
• 2 : a second embodiment of a component according to the invention in a sectional side view,
• 3 : a third embodiment of a component according to the invention in a sectional side view, and
• 4th : a plan view of an embodiment of an optically transparent layer according to the invention.

1 shows a first embodiment of a component according to the invention 2 in a sectioned side view. The base of the component 2 is made from a substrate 4th formed, which can be a flexible substrate. For example, the substrate 4th a PCB (English "printed circuit board", German circuit board) or an FCB (English "flexible circuit board", German flexible circuit board). On the substrate 4th is a light source 12 arranged. This light source 12 is preferably a light-emitting diode, for example a so-called sidefire LED. At one of the light sources 12 opposite end of the substrate 4th is a mirror element 14th , for example a mirror film, arranged. The mirror element 14th is optional and can improve the light output.

The light source 12 , the substrate and the mirror element 14th form a roughly U-shaped delimitation of a space in which the transparent layer is shown 8th , which can for example consist of an OCA adhesive, is arranged. In the transparent layer 8th are glass beads 10 embedded, which is located near the the substrate 4th remote surface 18th the transparent layer 8th are located. This surface 18th in the present case is the surface from which the light source 4th irradiated light from the optically transparent layer 8th and thus from the entire component 2 should be decoupled. It is also referred to below as the decoupling surface 18th designated.

In the figure on top of the transparent layer 8th is the delusion 6th arranged. The delusion 6th forms the visible side of the component 2 and closes the component from the outside. The substrate is in the installed state of the component 2 usually arranged on another component or connected to it. That of the optically transparent layer 8th facing side of the substrate 4th can have a reflective coating, so that in this way too the proportion of light that leaves the component as desired through the coupling-out surface is maximized.

Between the the substrate 4th and the optically transparent layer 8th a further layer, for example a film or other layer, can be arranged. The optically transparent layer 8th but can also be in direct contact with the substrate 4th and / or the veneer 6th stand. You can also choose between the veneer 6th and the optically transparent layer 8th another layer, for example a film, can be arranged.

In the illustrated embodiment, the optically transparent layer encloses 8th the glass balls completely. But it is also possible that the glass balls 10 partly or predominantly from the optically transparent layer 8th stick out. During an operating phase with activated lighting or backlighting, this is done by the light source 12 emitted light through the face 16 the optically transparent layer 8th coupled into this. The light is possibly on the mirror element 14th and or on that of the optically transparent layer 8th facing side of the substrate 4th reflected and finally on the glass balls 10 scattered and through the decoupling surface 18th from the component 2 decoupled. The decoupling surface 18th or not from the veneer 6th Covered areas are now perceived as luminous by a viewer. The veneer covers in the cross-section shown 6th the decoupling surface 18th completely off. In the case of a complete, three-dimensional representation or in a two-dimensional one A plan view of the component would, of course, be seen that the facing 6th Has recesses or optically transparent areas that can represent a symbol, for example.

2 shows a second embodiment of a component according to the invention in a sectional side view. Again, it is the substrate 4th , the light source 12 , the mirror element 14th , the delusion 6th and the transparent layer 8th with the glass balls 10 recognizable. The second embodiment shown differs from that in FIG 1 illustrated first embodiment in that the glass balls 10 near the the substrate 4th facing surface of the transparent layer 8th are arranged. This can be achieved, for example, by the transparent layer 8th , for example the OCA adhesive, when applied to the substrate 4th compared to the in 1 shown situation is turned around before joining.

3 shows a third embodiment of a component according to the invention in a sectional side view. Here, too, are the substrate 4th , the light source 12 , the mirror element 14th , the delusion 6th and the transparent layer 8th with the glass balls 10 to see. In this exemplary embodiment, the layer is optically transparent 8th executed in two parts. It consists of a lower OCA layer 20th and a top OCA layer 22nd that in turn through a slide 24 separated from each other. In the illustrated embodiment, only the upper OCA layer has 20th Glass balls 10 while the lower OCA layer 22nd free of glass balls 10 is. Depending on the viscosity of the OCA layers 20th , 22nd or. 8th can the glass balls 10 mobile within the layer 20th , 22nd or 8th be. The foil 24 forms a barrier between the two viscous layers 20th and 22nd that the glass balls cannot overcome and restricts the whereabouts of the glass balls 10 thus on the upper OCA layer 20th . Alternatively, the glass balls can also be in the lower OCA layer 22nd be arranged.

4th shows a plan view of an embodiment of an optically transparent layer according to the invention 8th . It's the OCA glue 8th to recognize on which the glass balls 10 are distributed. The glass balls 10 are packed as closely as possible so that only small spaces between the glass spheres 10 available. The glass balls 10 are arranged in the manner of a monolayer. In other words, there are only very small spaces between the glass spheres. Most of the glass balls 10 is in direct contact with at least one other glass ball 10 . At the same time, there is only a slight overlap between the individual glass spheres 10 . In other words, within the scope of the production accuracy, there are no areas in which several glass spheres are arranged one above the other, “one above the other” means here in an arrangement or sequence perpendicular to the main direction of extent of the coupling-out surface.

List of reference symbols

2

backlit component

4th

Substrate

6

Delusion

8th

OCA glue

10

Glass beads

12th

Light source

14th

Mirror foil

16

Interface

18th

Interface

20th

lower OCA layer

22nd

upper OCA layer

24

foil

26th

OCA layer with glass beads

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 202017104082 U1 [0005]

Claims (10)

Component (2) with at least one backlit surface, with 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 face (16) of the light-guiding layer (8) , characterized in that the light-guiding layer (8) consists at least predominantly of a highly viscous, optically transparent material, and that the light-guiding layer (8) has optically transparent micro-bodies (10). Component (2) after Claim 1 , characterized in that the light-conducting layer (8) consists at least predominantly of an OCA adhesive (8, 20, 22). Component (2) according to one of the preceding claims, characterized in that the optically transparent micro-bodies (10) are at least partially embedded in the light-guiding layer (8) and at least partially protrude from the light-guiding layer (8) on one side thereof. Component (2) according to one of the preceding claims, characterized in that the micro-bodies (10) form an essentially as densely packed layer as possible in the sense of a monolayer. Component (2) according to one of the preceding claims, characterized in that the micro-bodies (10) have a diameter in the range between 50 µm and 300 µm, preferably between 100 µm and 200 µm. Component (2) according to one of the preceding claims, characterized in that the light-guiding layer (8) consists of a first partial layer (20) and a second partial layer (22) which are separated from one another by a film (24), only one of which the sub-layers (20, 22) have micro-bodies (10). Component (2) after Claim 6 , characterized in that the light is coupled into the partial layer (20, 22) which has no micro-bodies Component (2) according to one of the preceding claims, characterized in that no micro-bodies (10) are arranged in surface areas in which no light is to be coupled out. Method for producing a backlit veneer for a surface, comprising the steps a. Providing a flexible substrate (4) b. Arranging a light source (12) on the substrate (4) c. Application of a flexible, highly viscous and optically transparent layer (8) on the substrate (4) in such a way that a light exit opening of the light source (12) points to an end face (16) of the transparent layer (8), the transparent layer (8) being optical has transparent micro-bodies (10). Procedure according to Claim 9 , characterized in that after step c. a three-dimensional deformation of the surface is carried out.

Images