EP2387864B1 - Method for producing a component that can be activated to emit light - Google Patents

Description

The invention relates to a method for producing a light-emission activatable component, wherein the light emission by electroluminescence (EL) takes place.

First of all, it should be stated that electroluminescence is the property of certain materials or combinations of materials, according to which light is emitted in the visible range when an electrical alternating voltage is applied. Electroluminescent films are known in practice, in which the electroluminescent material is excited by an alternating electric field in a special capacitor configuration. Such electroluminescent films are often also called luminescent films, light foils or capacitor luminescent films. In technical application, they serve to convert electrical energy into light.

Furthermore, there is a need in practice to illuminate or backlight components with any desired surface / topography. For example, reference is made to display instruments in the cockpit of a motor vehicle, on control buttons, buttons and other components, for example. Also information boards, etc ..

The abovementioned electroluminescent films can be used in an outstanding manner if the components to be illuminated or backlit and, if necessary, also to be transilluminated are components with simple geometries. With a complicated structure, in particular with a three-dimensional, strongly structured surface, the use of electroluminescent films is only possible to a limited extent. For example, the IMD technology (In Mold Decoration, cf. DE 197 17 740 C2 ), according to which films, such as, for example, electroluminescent films, are back-injected in order to produce moldings by injection molding technology. However, highly structured surfaces, in particular in the case of miniaturized components having an electroluminescent surface, can not be produced by this known method.

In particular, in classical Tachoadeln previously light-conducting systems are used to illuminate, it being necessary to couple the light in the rotating or oscillating / pivoting Tachonadel. This is technically complicated. Nevertheless, this technique has so far been predominantly realized.

From the DE 101 52 919 A1 For example, a method for producing an organic electroluminescent display is previously known. In this case, a first electrode layer 5A is produced on a substrate 1 and a first insulating layer is applied to the substrate 1 or the first electrode layer 5A. Subsequently, the first insulating layer is patterned into strip-like webs 10 such that they delimit a region provided for functional layers. In this area, the functional layers 20 are applied over a large area, for example by pad printing processes, and then a large area of a second electrode layer 25A is produced on the functional layers 20.

The present invention is based on the object of specifying a method for producing a component which can be activated for the emission of light, in which the light emission is effected by electroluminescence (EL). With the method according to the invention, it should be possible to provide almost arbitrarily structured surfaces, in particular also very small or filigree components, with electroluminescent layers, so that it is possible, in this way any functional parts on the surface, inside the material or behind to illuminate the workpiece / component.

According to the invention, a carrier is firstly produced or provided, wherein the carrier essentially comprises or comprises the shape of the component and its mechanical and electrical interfaces, the carrier comprising a region serving as a mechanical interface, which is equipped at least with parts of the electrical interface is. It is essential that the carrier is a kind of blank for the component to be produced, namely a blank which does not yet possess the electroluminescent property. Mechanical interfaces, for example in the form of an integral coupling part, can be an integral part of the carrier. Electrical interfaces can also already from be provided in advance or would be produced in the course of the manufacturing process on the surface - at the appropriate place.

With regard to the method according to the invention, it is of very particular importance that the carrier is provided with functional layers of the EL illumination, wherein at least one of the functional layers, namely the light-emitting layer or layers, as a whole or at least partially, is produced by the pad printing method. become. The electrical interfaces are - at least in the field of functional layers - involved in the printing, so that simultaneously with the printing technology production of the light-emitting layer / layers an electrical contact is created. A subsequent contact, usually with a considerable design or manufacturing effort, is not required.

After the functional layers of the EL illumination have been produced, a transparent or translucent cover is applied to the EL layers, which on the one hand serves as moisture protection and on the other hand as electrical and mechanical encapsulation. Consequently, with the application of the cover, the light-emission activatable component, for example a tachometer needle, is completed.

As already stated above, at least the light-emitting layer is produced by means of pad printing. This is an indirect printing process, which works according to the so-called gravure printing principle. The tampon absorbs the color according to the outer contour of the cavity of the plate and forms it when printing on a component of any surface. These can be bounded or sequential regions and various shapes, also sequentially limited.

While the tampon printing process has hitherto usually been used predominantly for printing plastic bodies in the advertising industry, it has been recognized here that this process is particularly suitable for producing a light-emitting layer in the context of EL lighting, especially since the color is also used in this process on three-dimensional surfaces, for example, in deeper areas, is printed. As part of the application of the Pad printing is also of particular importance that the color transfer to the respective carrier is close to 100%, namely due to the pad printing process underlying technology. Already by the manufacturing costs can be significantly reduced. It is also conceivable to print in several layers, resulting in brighter and darker light emissions.

The carrier may have almost any topology on the surface. In principle, this may be a rigid or inherently flexible material, for example in the form of an MID or metal-containing flexible plastics. On structured surfaces, the electroluminescent layer can be applied by means of the pad printing method, the carrier in front of it already being provided with the electrical connections. Thus, simultaneously with the application of the EL layer, a contacting and also insulation between the different EL layers can be carried out, wherein insulation layers can be applied or produced as desired. In addition to printing technology processes for the realization of the contact surface, the injection molding technique can be applied without further ado.

The electrical connections or the electrodes of the EL functional layers can be produced in different ways, for example by injection molding and / or printing technology. It is conceivable to produce the electrical connections on and / or in the carrier. By overprinting or coating the connections, these can be electrically coupled or insulated, depending on the material used. It is also possible to produce mask-like coatings or layers on the electrical connections / electrodes.

The light-emitting layer (s) is / are printed in the form of word and / or picture information as needed. Tampon printing can be used to produce structured surfaces along the surface profiles as well as strictly delimited areas with and without light-emitting layers. The variety of information that can be produced in this way has no limits. In particular, the light-emitting layer can optionally be formed on different levels, for example in such a way that any interruptions and repeated electrical connections are made by directly printing the electrical connections possible are. Wherever necessary, insulating intermediate areas or intermediate layers can also be produced by printing technology or injection molding technology.

The functional layers are printed in any case with the interposition of insulators, namely to produce the full functionality of the EL functional layers.

It should be noted at this point that, according to the method according to the invention, at least the light-emitting layer (s) is / are produced by the pad printing method. In principle, it is conceivable to produce further functional layers, including further light-emitting layers, both by means of pad printing and by injection molding, lacquer technology, etc. The same applies to the insulators that are absolutely necessary for the construction of the EL functional layers. Furthermore, it should be noted at this point that EL lighting, using EL functional layers, means any structure of such functional layers, for the production of so-called EL lamps. It is not considered necessary to describe at this point a concrete structure or a concrete interconnection, especially as these are well known from numerous reference works. By way of example only - in addition - on the DE 102 34 125 A1 referred to, according to which the EL functional layers are provided in the form of an EL film.

The EL functional layers, or at least the cover which encapsulates the light-emitting layer, can be produced in the so-called 2K reaction process, the CCM process (clear coat moldering) being particularly suitable. With the aid of this method, a kind of macroencapsulation of the EL functional layers is possible, whereby the outer contour of the component can be masked or even a shape realized. The material used here can be made crystal clear so that it is transilluminated by the underlying EL lamp generated by the EL functional layers. It is also conceivable to color the material of the cover or encapsulation. This makes it possible to generate a color filter in an ideal way.

It is also conceivable to coat the EL functional layers with a translucent lacquer, wherein a so-called laser lacquer can be drawn over it. With the help of a laser, the lasable paint is literally burned off, so that any luminous geometries and thus overall the contour of the luminous surface can be generated on the surface of the component.

The cover, which can be generated at any time, can be applied with contours and / or reworked with respect to the surface. Finally, even a processing of the outer contour is possible. This measure (s) also makes it possible to produce any desired surface structures, in which case the EL functional layers are located underneath.

It should also be noted that the carrier can comprise or contain any desired electronic components, in particular in a highly miniaturized form. It is also conceivable to associate the carrier with its own current / voltage source, for example using solar-thermal layers, namely to create a quasi-self-sufficient component. In particular, it is conceivable that the support, for example, by vacuum casting, any functional elements are incorporated or become. Again, there are no limits.

Fig. 1

in einer schematischen Ansicht den grundsätzlichen Aufbau eines Ausführungsbeispiels eines erfindungsgemäßen Bauteils mit den zur Lichtemission erforderlichen EL-Funktionsschichten,

Fig. 2

in einer schematischen Ansicht den beispielhaften Aufbau eines eine sog. EL-Lampe umfassenden Bauteils mit mechanischer und elektrischer Schnittstelle und

Fig. 3

in einem Flussdiagramm, schematisch, mögliche Verfahrensschritte zur Herstellung eines zur Lichtemission aktivierbaren Bauteils.

There are now various possibilities for designing and developing the teaching of the present invention in an advantageous manner. For this purpose, on the one hand to the claims subordinate to claim 1 and on the other hand to refer to the following explanation of preferred embodiments of the invention with reference to the drawings. In conjunction with the explanation of the preferred embodiments of the invention with reference to the drawings, also generally preferred embodiments and developments of the teaching are explained. In the drawing shows

Fig. 1

2 is a schematic view of the basic construction of an exemplary embodiment of a component according to the invention with the EL functional layers required for light emission,

Fig. 2

in a schematic view of the exemplary structure of a so-called. EL lamp comprehensive component with mechanical and electrical interface and

Fig. 3

in a flowchart, schematically, possible process steps for producing a light-emitting activatable component.

Fig. 1 shows an embodiment of a device produced by the method according to the invention, which comprises an activatable for light emission EL lamp.

The in Fig. 1 The construction shown reveals that the component initially comprises a carrier 1. This can be any plastic substrate. The concrete form does not matter.

On the carrier 1, a back electrode 2 is applied. Furthermore, a ground line 3 is provided. These are the electrical connections of the component.

The back electrode 2 is covered by a dielectric 4. Through the dielectric 4, the rear electrode 2 is also isolated from the ground line 3.

On the dielectric 4, an electroluminescent layer 5 is applied, by pad printing. The electroluminescent layer 5 is covered by a conductive ink 6, which simultaneously electrically contacts the ground line 3. All functional layers of the EL lighting can be printed.

Furthermore, the entire arrangement is covered with a sealing encapsulation 7, which acts as a macro-encapsulation, namely in the sense of moisture protection and for electrical and mechanical encapsulation of the entire structure.

Fig. 2 shows a schematic view of another component, which has been produced by the process according to the invention, namely also with an integrated EL lamp.

The carrier 1 comprises electrical and mechanical coupling means 8, wherein the contacting with an AC voltage source 9 is indicated. Between the carrier element 1 and an electrically conductive connection pin 10, an insulation 11 made of plastic is provided. Consequently, it is possible to do so in Fig. 2 at the same time coupled mechanically and electrically, namely due to the electrical / mechanical coupling means 8 provided there.

The EL lamp of the in Fig. 2 shown component is similar to the EL lamp of in Fig. 1 constructed component. The return electrode 2 is formed by the connection pin 10. On it sits the dielectric 4, which surrounds the connection pin 10 together with the insulation 11. On the dielectric 4, the EL layer 5 is applied, which in turn is surrounded with conductive ink 6.

At the in Fig. 2 selected embodiment, a color layer 12 is applied to the conductive ink 6, which serves in terms of the light emission from the EL layer 5 as a color filter.

The entire assembly is CCM overmolded, whereby the outer shape of the component is more or less defined according to the predetermined basic shape. The CCM encapsulation 13 is made of a transparent material.

The whole is provided on the surface with a coating 14, which does not let light through. The coating 14 is again - partially and with any structure / shape - recessed, namely with at least one viewing window 15, through which the light can emit. Due to the shape of the viewing window 15, the "luminous" surface and thus the information to be conveyed can be defined as desired.

Fig. 3 shows in a flowchart the implementation of the method according to the invention with alternative method steps. Due to the caption is Fig. 3 of course.

Thus, for example, it is conceivable that the carrier is first inserted into a tool holder, wherein the carrier may comprise mechanical and electrical coupling means.

In a next step, the individual functional layers, for example, in the pad printing process, printed on the two-dimensional or three-dimensional electrical contact surfaces of the carrier or the substrate. Thereafter or at the same time it is possible to refine the carrier according to the IMD technique already discussed above, wherein it is conceivable to incorporate electrical components into the carrier.

After generation of the EL lamp, a pluggable, ready-to-assemble or insertable or castable macro-encapsulation is possible, for example according to the CCM method. It is also conceivable to put a prefabricated housing over the entire arrangement.

Thereafter, a translucent cover can be produced on the printed carrier or substrate. A seal of the interface between the printed carrier / substrate and the encapsulation is advantageous. Such a seal can be produced by gluing, hot stamping, ultrasonic welding, etc. Subsequently, the component can be painted or printed again as well as lasers.

Alternatively, the component carrying the EL layers is painted / lasered and then overmolded in accordance with CCM or encapsulated in accordance with CCM and subsequently painted / lasered. It is an activatable for light emission component corresponding to the description of the Fig. 1 and 2 emerged.

It should be noted at this point that the method discussed above merely schematically depicts the inventive concept. Any further method steps, in particular for the refinement of the method, are conceivable.

With regard to the teaching according to the invention, it should be stated once again that any components which comprise EL functional layers can be produced by the method according to the invention. These can be any display and control elements with integrated EL lighting. In particular it is conceivable to realize miniaturized, movable components according to the inventive method, which allow a rotational or linear movement.

The EL devices in question here can have information / symbols with the highest position accuracy, which is extremely difficult to implement in the application of the IMD method. It is possible to realize a simplified production with a minimum number of components.

In the method according to the invention, the shape of the EL component, in particular the desired light exit surface, can be freely defined in terms of shape and size. There are hardly any restrictions with regard to the electrical and optical or lighting requirements.

The method according to the invention makes it possible to produce a simple, safe and temperature-changeable and corrosion-resistant contacting between the electrical connections of a voltage source and the electrodes of the EL lamp.

The enclosing macroencapsulation prolongs the life of the component, for example by the use of clear casting. In addition, the EL pigments in the light-emitting layer are spared during the manufacturing process. It is possible to produce an improved UV protection of the EL pigments by coloring the encapsulation material or potting material.

Of very particular importance is the producible according to the inventive EL device, which meets the specifications and the popular decor of the automotive industry. It's easy to create a day and night design.

For example. For example, the component activatable for light emission could be a tachometer needle whose construction is characterized by a few parts. Particularly in the case of such a tachometer needle, previously known light guidance systems can be substituted by the EL lamp being printed directly on the blank. This allows a much simpler structure and a streamlined, process-reliable and inexpensive manufacturing possible. In particular in terms of their functionality, such EL pointers are superior to the conventional components.

In concrete terms, the tachometer needle can achieve optimal illumination or illumination over the entire illuminated area and length. Also, mechanical requirements can be justified by the method according to the invention, in particular with respect to a jerk-free movement of the tachometer needle. The weight distribution is almost freely definable.

LIST OF REFERENCE NUMBERS

1

carrier

2

back electrode

3

ground line

4

dielectric

5

electroluminescent layer (EL layer)

6

Leitlack

7

encapsulation

8th

electrical / mechanical coupling means

9

AC voltage source

10

Connection pin

11

insulation

12

coat of paint

13

encapsulation

14

paintwork

15

window

Claims (10)

1. Method for producing a component which can be activated for light emission, wherein the light emission is carried out by means of electroluminescence (EL),
   having the following method steps:

   providing or producing a carrier, substantially in the form of the component and the mechanical and electrical interfaces thereof, wherein the carrier comprises a region which acts as a mechanical interface and which is provided at least with portions of the electrical interface,

   printing the carrier with functional layers of the EL illumination, wherein at least one of the functional layers, that is to say, the light emitting layer or layers - on the whole or at least partially - is/are produced using the pad printing method and wherein the electrical interfaces are incorporated in the printing,

   producing a transparent or translucent cover as moisture protection and for electrical and mechanical encapsulation.
2. Method according to claim 1, characterised in that the carrier is constructed to be rigid or flexible per se, for example, with rigid or flexible printed conductors.
3. Method according to claim 1 or claim 2, characterised in that the electrical connections or electrodes are produced and overprinted on and/or in the carrier using injection-moulding technology and/or printing technology.
4. Method according to any one of claims 1 to 3, characterised in that the light emitting layer is printed in the form of word and/or image information.
5. Method according to any one of claims 1 to 4, characterised in that the light emitting layer is constructed in a zonal manner and optionally in different planes.
6. Method according to any one of claims 1 to 5, characterised in that the functional layers are imprinted with insulators being interposed.
7. Method according to claim 6, characterised in that the insulators are produced using injection-moulding technology, painting technology or printing technology.
8. Method according to any one of claims 1 to 7, characterised in that the covering is applied with a 2K reaction method, in particular a CCM method (Clear Coat Moulding).
9. Method according to any one of claims 1 to 8, characterised in that the covering is applied with contours and/or is finished with respect to the surface.
10. Method according to any one of claims 1 to 9, characterised in that the carrier comprises electronic modules and/or a current/voltage source.

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