EP1656818A1 - Polychromatic electrolumeniscent element and method for the production thereof - Google Patents

Polychromatic electrolumeniscent element and method for the production thereof

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Publication number
EP1656818A1
EP1656818A1 EP04763573A EP04763573A EP1656818A1 EP 1656818 A1 EP1656818 A1 EP 1656818A1 EP 04763573 A EP04763573 A EP 04763573A EP 04763573 A EP04763573 A EP 04763573A EP 1656818 A1 EP1656818 A1 EP 1656818A1
Authority
EP
European Patent Office
Prior art keywords
electroluminescent
color
element according
electroluminescent element
film
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP04763573A
Other languages
German (de)
French (fr)
Other versions
EP1656818B1 (en
Inventor
Manfred Hartmann
Oliver Narwark
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Schreiner Group GmbH and Co KG
Original Assignee
Schreiner Group GmbH and Co KG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Schreiner Group GmbH and Co KG filed Critical Schreiner Group GmbH and Co KG
Publication of EP1656818A1 publication Critical patent/EP1656818A1/en
Application granted granted Critical
Publication of EP1656818B1 publication Critical patent/EP1656818B1/en
Not-in-force legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B33/00—Electroluminescent light sources
    • H05B33/12—Light sources with substantially two-dimensional radiating surfaces
    • H05B33/14—Light sources with substantially two-dimensional radiating surfaces characterised by the chemical or physical composition or the arrangement of the electroluminescent material, or by the simultaneous addition of the electroluminescent material in or onto the light source
    • H05B33/145—Arrangements of the electroluminescent material
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B33/00—Electroluminescent light sources
    • H05B33/12—Light sources with substantially two-dimensional radiating surfaces
    • H05B33/22—Light sources with substantially two-dimensional radiating surfaces characterised by the chemical or physical composition or the arrangement of auxiliary dielectric or reflective layers
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B33/00—Electroluminescent light sources
    • H05B33/12—Light sources with substantially two-dimensional radiating surfaces
    • H05B33/26—Light sources with substantially two-dimensional radiating surfaces characterised by the composition or arrangement of the conductive material used as an electrode
    • H05B33/28—Light sources with substantially two-dimensional radiating surfaces characterised by the composition or arrangement of the conductive material used as an electrode of translucent electrodes

Definitions

  • the present invention relates to a multicolor electroluminescent element and a method for its production.
  • Electroluminescence technology has recently become increasingly important. It enables the realization of almost any size, glare-free and shadow-free, homogeneous illuminated surfaces. The power consumption and depth (in the order of a millimeter and below) are extremely low.
  • the typical application also includes the backlighting of transparent films which are provided with lettering and / or image motifs.
  • Electroluminescence is the direct luminescence excitation of luminescent pigments or luminophores by an alternating electrical field.
  • Electroluminescent elements based on the so-called thick-film technology with inorganic luminous pigments or luminophores and AC excitation have largely become established. Compared to thin-film EL elements, thin-film EL elements are less complex and therefore less expensive to manufacture.
  • the luminous pigments or luminophores are embedded in a transparent, organic or ceramic binder.
  • the starting materials are mostly zinc sulfides, which depend on the doping or co-doping and the preparation process generate different, relatively narrow-band emission spectra. The focus of the spectrum determines the respective color of the emitted light.
  • the exciting AC voltage field generally has a frequency of a few hundred Hertz, the effective value of the operating voltage often being in a range from approximately 50 to 150 volts.
  • a higher luminance can generally be achieved, which is usually in a range from approximately 50 to approximately 200 candelas per square meter.
  • Increasing the frequency usually causes a color shift towards lower wavelengths.
  • both parameters must be coordinated to achieve a desired lighting impression.
  • ITO indium tin oxide electrodes
  • plastic films plastic films. They are very thin (some 100 ⁇ ) and offer the advantage of high transparency with a relatively low surface resistance (approx. 60 to 600 ohms). However, they cannot be applied to structured surfaces with steps, are not deformable, and cannot be applied to substrates that easily outgas in a vacuum.
  • printing pastes with ITO or ATO (antimony tin oxides, antimony tin oxide) or intrinsically conductive transparent polymer pastes can be used. With a thickness of approx. 5 to 20 ⁇ m, such electrodes only offer less transparency with a high surface resistance (up to 50 kOhm). However, they can largely be applied in any structure, even on structured surfaces. They also offer relatively good laminatability and limited deformability.
  • the lifespan of an EL element is limited. It mainly depends on the level and frequency of the AC voltage applied, but also on environmental influences, in particular the effects of moisture and UV radiation.
  • the service life of an EL element is usually given as the half-life of the luminescent pigments. This is the time after which the luminance under the influence of the electric field has decreased by half of the initial value under unchanged operating conditions. In practice, the luminance is roughly within 2000 to 3000 operating hours to half of the original value.
  • the emission color of an EL element can be adapted to the desired color impression by a variety of possible measures. These include the doping and co-doping of the luminous pigments, the mixture of two or more EL pigments, the addition of one or more organic and / or inorganic color-converting and / or color-filtering pigments, the coating of the EL pigment with organic and / or inorganic color-converting and / or color-filtering substances, the incorporation of colorants into the polymer matrix in which the luminous pigments are dispersed, and the incorporation of a color-converting and / or color-filtering layer or film into the structure of the EL element.
  • Luminophores which emit a pure white, are not yet available. For this reason, whitish-glowing EL elements are often produced using a mixture of at least two luminescent pigments, the emissions of which add up to (almost) white. In order to obtain pure white, it is usually necessary to use an organic conductive varnish with a light blue color. However, the different aging of the two luminescent pigments causes a change in the color impression over the course of the service life, which is often very disruptive or unacceptable for the planned application. Furthermore, there are almost white luminophores, which, however, contain toxic zinc selenides and are therefore reluctant to use them.
  • Corresponding EL elements are referred to as multicolor electroluminescent elements.
  • Multi-color electroluminescent elements are known, inter alia, from EP-A-104561 8. It describes a multi-colored EL lamp in which different colors result from additive color mixing, in that at least two electroluminescent layers lying one above the other and containing luminescent pigments are appropriately controlled by means of at least three electrode layers.
  • the first electrode is produced by vapor deposition of ITO on a PET substrate, whereas all further layers, that is to say also all further electrodes, are produced by means of screen printing.
  • EP-A-0998171 also describes a multi-layer EL element with different patterns and many luminescent colors.
  • the first transparent electrode is produced by vapor deposition or sputtering onto a PET film. All other electrodes are produced by printing optically transparent pastes.
  • a multi-color EL element is known from EP-A-0973358, which has a plurality of transparent electrode layers and a plurality of luminescent layers with different colors. According to this document too, a multi-layer printing technology is implemented.
  • the multicolor electroluminescent element which, depending on the electrical control, can assume different luminous colors and yet can be produced in a high quality with reasonable effort. Associated with this is the task of providing a suitable manufacturing process for multi-color EL elements, which enables high product quality with little waste. According to one aspect of the present invention, this object is achieved by a multicolor electroluminescent element according to claim 1. Contrary to the prior art, according to which multicolor electroluminescent elements are designed as a multilayer screen printing structure on a film, the multicolor electroluminescent element according to the invention is constructed from at least two electroluminescent films, each with a luminescent layer.
  • An electroluminescent film is to be understood as a coherent film body with a certain dimensional stability, which stems from the fact that the luminous layer of the electroluminescent film is applied to a stable film substrate (as a support) and / or itself consists of a preferably cast film, in the matrix of which the dispersed Luminophores are stored.
  • a stable film substrate as a support
  • / or itself consists of a preferably cast film, in the matrix of which the dispersed Luminophores are stored.
  • Different colors are generated by additive color mixing, in that each luminescent layer, each emitting in a different color, is excited differently by a separately controlled alternating electric field.
  • a separately controlled alternating electric field With three electroluminescent foils in the colors red, green and blue, the entire color spectrum including white can be displayed with appropriate control.
  • the object is achieved by a method for producing a multicolor electroluminescent element according to claim 23.
  • a method for producing a multicolor electroluminescent element according to claim 23 Contrary to the state of the art, not all individual layers of the EL element are applied sequentially, so to speak "from bottom to top", one above the other in terms of printing technology, but at least two prefabricated electroluminescent films, for example by lamination, assembled.
  • the problems described above with the wiring of the electrodes are largely eliminated.
  • the connections of the electrodes on the individual electroluminescent foils can be produced separately prior to assembly according to controllable techniques that are common for conventional single-color electroluminescent elements.
  • 1 a to 1 k show different basic arrangement variants in the layer structure of multicolor electroluminescent elements according to the invention, in each case once before joining the electroluminescent films and afterwards. Any additional insulating or adhesion promoter layers contained in the structure are not shown.
  • FIG. 2 shows an example of a multicolor electroluminescent element composed of three electroluminescent foils, in each case before the electroluminescent foils are joined together and afterwards, each electroluminescent foil having a stable foil substrate.
  • FIG. 3 shows an example of a multicolor electroluminescent element composed of three electroluminescent films, in each case before the electroluminescent films are joined together and afterwards.
  • the structure is similar to that in FIG. 2, but the middle electroluminescent film does not have a film substrate, but its film property stems from the cast matrix of the luminescent layer.
  • 4 shows the structure of an electroluminescent film of a particularly preferred multicolor electroluminescent element according to the invention.
  • Three (possibly also two) similar electroluminescent films of the type shown, which differ only in their luminous color, are combined with one another.
  • FIGS. 1 a to 1 k show examples of various fundamentally possible arrangement variants of the layer structure of multicolor electroluminescent elements according to the invention.
  • the partial representation on the left in each case shows the electroluminescent films 1, 2, 3 before the assembly, and the partial representation on the right shows the layer structure of the multicolor electroluminescent element which has subsequently formed.
  • further layers, in particular dielectric or insulating or adhesion promoter layers can be contained in the respective structure, which are not shown for the sake of clarity.
  • the adhesion promoter layers serve to connect the electroluminescent films to one another.
  • Color filtering or color converting layers and imprints (not shown) can also be included in order to produce a desired color impression. These can also be provided only over part of the area in order to achieve certain graphic designs.
  • Each electroluminescent film 1, 2, 3 has a luminescent layer 1 1, 1 2, 1 3 with disperse electroluminophores 4, which are preferably cast films in whose film matrix 6 the electroluminophores 4 are embedded. Extruded foils are also possible, but these are less advantageous due to the often less favorable distribution of the electroluminophores.
  • the representation of the electroluminophores 4 is to be understood purely schematically. In practice, efforts are made to obtain particles that approximate the spherical shape. Electroluminophores are usually sensitive to the effects of moisture. For this reason, additional layers are usually integrated into the layer structure of conventional electroluminescent elements, which take on the function of a moisture barrier or vapor barrier.
  • Corresponding layers can also be integrated into the structure of the multicolor electroluminescent element according to the invention. However, these can largely be eliminated, in particular, if micro-encapsulated electroluminophores 4 are used.
  • the microencapsulation is usually oxidic or nitridic, however, organic microencapsulation or diamond-like carbon encapsulation ("diamond-like carbon") is also conceivable.
  • the first electroluminescent film 1 has a Qe, largely transparent or reflectively opaque) electrode layer 21 and a largely transparent back electrode layer 31, depending on the application. Together with the first luminous layer 11 arranged in between, they form a first electroluminescent capacitor.
  • the second luminescent layer 1 2 belonging to the second electroluminescent film is provided with only one largely transparent electrode layer 22. In the fully assembled multicolor electroluminescent element, the electrode layer 22 and the second luminescent layer 12 together with the back electrode layer 31 of the first electroluminescent film 1 form a second electroluminescent capacitor.
  • the multicolor electroluminescent element shown in FIG. 1b is largely constructed like the multicolor electroluminescent element in FIG. 1a. However, in order to achieve better controllability, the second luminescent layer 1 2 also has its own back electrode layer 32. Back electrode layer 32 and electrode layer 22 can also be interchanged.
  • the structure shown in FIG. 1b makes it necessary to provide an insulating layer 42 on the connection surface between the first electroluminescent film 1 and the second electroluminescent film 2 in order to avoid short circuits.
  • 1 c and 1 d each show a multicolor electroluminescent element with three electroluminescent films 1, 2, 3.
  • Each of the luminescent layers 11, 12, 13 emits with a different color due to different electroluminophores 4, so that the variety of colors that can be achieved by means of additive color mixing is even greater.
  • red electroluminophores 4 it is possible in principle to display the entire color spectrum.
  • red electroluminophores are usually not used because they contain cadmium, which is toxic.
  • a red fluorescent color can also be achieved by means of color-converting or color-filtering substances.
  • the at least four electrodes required for a "three-color" structure can be distributed differently before being joined together.
  • an electrode layer 22 and a back electrode layer 32 can also be arranged on the second electroluminescent film 2, as shown in FIG. 1 c, while the third, middle electroluminescent film 3 does not necessarily have its own electrode layer is needed. Or the second electroluminescent film 2 does not have a back electrode layer 32, for this the third electroluminescent film 3 is provided with its own electrode layer 23.
  • the structure shown in Fig. 1 e or Fig. 1 f corresponds essentially to the structure shown in Fig. 1 a.
  • the first electroluminescent film 1 (FIG. 1e) or the second electroluminescent film 2 (FIG. 1f) has a stable film substrate 51, 52.
  • the corresponding electrode layer 21, 22, preferably made of ITO (indium tin oxide), can then be sputtered or vapor-deposited onto the film substrate 51, 52, for example by vacuum technology.
  • the transparent or at least partially transparent film substrate 51, 52 consists of a polymeric or copolymeric film, for example made of polycarbonate (PC) or polyalkylene terephthalates or polyamide (PA) or polyacrylate or polymethacrylate or polymethyl methacrylate (PMMA) or polyurethane (PUR) or polyoxymethylene (POM) or ABS graft polymers or polyolefins, such as polyethylene (PE) or polypropylene (PP), or polystyrene (PS) or polyvinyl chloride (PVC) or polyimide (Pl) or polyetherimides (PEI) or polyether or polyether ketones (PEK) or polyvinyl fluoride (PVF) or polyvinylidene fluoride (PVdF) or similar films which have high transparency in the optically visible wavelength range.
  • PC polycarbonate
  • PA polyalkylene terephthalates
  • PA polyamide
  • PMMA polymethacrylate or polymethyl methacrylate
  • the film substrate 51, 52 acts as a stabilizing support, the corresponding luminescent layer 1 1, 1 2 no longer necessarily requires particular intrinsic stability, so that the luminescent layer 1 1, 12 is not only designed as a (cast) film, but instead also as a screen printing layer or the like can be.
  • FIG. 1 g and 1 h show a structure corresponding to FIG. 1 c and FIG. 1 d, the first electroluminescent film 1 having a film substrate 51 of the type described above.
  • the structure of the multicolor electroluminescent element shown in FIG. 1 i largely corresponds to the structure shown in FIG. 1 b, wherein both electroluminescent films 1, 2 have a film substrate 51, 52 of the type described above. It is thus possible to use two almost identical electroluminescent films 1, 2, which differ only in the color of their electroluminophores 4. By adding a third electroluminescent film (not shown) that differs only in its luminescent color, an RGB arrangement for displaying the entire color spectrum is also possible.
  • FIG. 1j and 1k show a structure corresponding to FIG. 1g and FIG. 1h, wherein in addition to the first electroluminescent film 1, the second electroluminescent film 2 also has a film substrate 52 of the type described above.
  • the (rear) electrode layers 21, 22, 23, 31, 32, 33 are generally contacted over the entire edge of the electrode surface by means of conductors which are guided in a ring around the electrode surface. This has the advantage that, despite the not inconsiderable surface resistance of the thin electrode layers 21, 22, 23, 31, 32, 33, there are no excessively large potential differences across the surface, and therefore the homogeneous lighting effect is supported. Furthermore, individual electroluminescent films 1, 2, 3, but also the entire multicolor electroluminescent element can be divided into segments, with individual segments are each separately electrically contacted and can also be controlled separately in order to be used as a segment display for displaying different patterns or graphics or else characters.
  • FIG. 2 A somewhat more detailed illustration of a "three-color" (RGB) emitting multicolor electroluminescent element is shown in FIG. 2.
  • the left partial illustration shows the electroluminescent films 1, 2, 3 before the assembly, and the right partial illustration shows the layer structure of the multicolor electroluminescent element which has subsequently been created.
  • a pressure-sensitive adhesive layer 7 is provided on the first, lowermost electroluminescent film 1 for simplified attachment to a base. Otherwise, the individual electroluminescent films 1, 2, 3 are largely the same and essentially constructed in accordance with FIG. 1 i (only the luminescent layers 1 1, 1 2, 1 3 naturally emit in a different color, expediently red, blue and green):
  • ITO indium tin oxide
  • This electrode layer 21, 22, 23 can be structured conventionally by means of a scratch-cut plotter or by means of etching or by laser action in accordance with the desired formation of several segments and the corresponding connection wiring, or can be used over the entire area. It is also possible to partially ablate the electrode layer 21, 22, 23 in the finished or semi-finished electroluminescent film 1, 2, 3 or even in the finished or semi-finished multi-color electroluminescent element, so to speak, to structure and thus contour it.
  • bus bars i.e. more conductive wiring elements
  • Silver conductive pastes and / or copper conductive pastes and / or carbon conductive pastes are produced.
  • the respective luminescent layer 11, 1, 13 is preferably produced by screen printing in the form of electroluminophores 4 or EL pigments 4 dispersed in a transparent polymer matrix 6 in the desired graphic configuration.
  • suitable EL pigments 4 or EL pigment mixtures 4 are used and / or suitable color-converting and / or color-filtering substances are added to the binder of the matrix 6.
  • color-converting and / or color-filtering effects can also be brought about by applying a corresponding layer 61, 62, 63 to the top of the substrate 51, 52, 53 and / or laminating a corresponding film by means of further printing.
  • a dielectric layer 41, 42, 43 it may be expedient to apply a dielectric layer 41, 42, 43 to the luminescent layer 1 1, 1 2, 1 3. If a screen printing process is used, a second dielectric layer 81, 82, 83 is advantageously applied, as a result of which small imperfections and / or micro-air inclusions are covered and the insulation property is improved.
  • transparent polymeric dielectric layers 41, 42, 43, 81, 82, 83 are preferably used according to the invention, whereby the smallest possible layer thickness must be taken into account, since usually no additions which increase the relative dielectric constant can be added, since such , for example consisting of fine barium titanate pigments, admixtures would have a very strong influence on the transparency and would usually bring about an undesired opacity with strong reflection.
  • the (largely) transparent back electrode 31, 32, 33 is preferably produced by means of screen printing in the form of an intrinsically conductive polymer layer and / or a layer with metal oxides, for example indium tin oxides (ITO) or antimony tin oxides (ATO).
  • ITO indium tin oxides
  • ATO antimony tin oxides
  • the back electrode 31, 32, 33 can be designed largely freely in graphic and functional terms. Since conventional electrically conductive screen printing pastes do not have good surface conductivity, so-called bus bars (not shown) are printed bordering or bordering, especially in the case of larger areas, by means of well electrically conductive pastes. These bus bars can also be used for the execution of the electrical connections are used.
  • the back electrode 31, 32, 33 can also be produced over the entire surface by means of doctor blades, roller coating, curtain casting, spraying and the like.
  • adhesion promoter layers 72, 73 can be applied which bring about and / or improve the bond between the individual electroluminescent films 1, 2, 3.
  • An adhesion promoter layer 71, 72, 73 is primarily understood to mean a transparent polymeric connecting layer. This can create a connection in the cold adhesive process after peeling off a protective film and application by means of pressure. However, hot-melt adhesive coatings can also be used, which bring about an adhesive bond under temperature and pressure. Since a composite that is as optically transparent as possible is required, the adhesive layer 71, 72, 73 must be transparent and the composite must be designed free of air inclusions. Furthermore, the adhesion promoter layer 72, 73 is also intended to compensate for unevenness in the preceding layers.
  • connection of the electroluminescent films 1, 2, 3 by means of cold lamination and / or hot lamination can take place flat or element-wise.
  • connection can also be made only at points or in strips, since if necessary the three electroluminescent films 1, 2, 3 are fixed together when installed in a corresponding application.
  • the dielectric layers 41, 81 and the back electrode 31 of the lowermost electroluminescent film must be made largely transparent, while one or more of the layers mentioned are preferably designed to be opaque or reflective for one-sided light emission upwards, and the back electrode 31 additionally takes on various wiring functions can.
  • the arrangement blue-red-green, with green being arranged on the light exit side was very efficient for generating one as large a variety of colors as possible, and in particular to produce the color white.
  • the EL pigments 4 or the combinations of EL pigments 4 and the use of corresponding color-converting and / or color-filtering substances other arrangements or a different sequence can also be used.
  • the luminescent layer 1 1, 1 2, 1 3 can be formed from an EL cast film.
  • EL cast films are understood to mean thin films produced from the solution by means of casting processes, in which the electroluminescent pigments with a diameter of less than 30 ⁇ m, preferably less than 20 ⁇ m, particularly preferably less than 15 ⁇ m, are embedded.
  • Such EL cast films are relatively dimensionally stable and can preferably be coated in a roll-to-roll process with electrode layers 21, 22, 23 by means of vacuum technology or screen printing or knife coating or roll coating or spraying or curtain casting.
  • the application of the dielectric layers 41, 42, 43, 81, 82, 83 can be dispensed with and thus very good transparency and electrical dielectric strength and excellent surface planicity can be achieved.
  • the disadvantage of this method lies in the full-surface design of the luminescent layers 1 1, 1 2, 1 3 and thus the higher costs due to an increased proportion of EL pigments 4.
  • FIG. 3 shows an alternative embodiment, the reference numbers of corresponding layers being retained compared to FIG. 2.
  • the middle electroluminescent film 3 can be formed using an EL cast film as the luminescent layer 13.
  • the other electroluminescent films 1, 2 can in principle be designed without the film substrate 51, 52 if the luminescent layers 11, 12 are produced accordingly.
  • An advantage of the arrangement shown in FIG. 3 is the saving of one or two electrode layers.
  • a mirror-image structure of the upper and lower electroluminescent films 1, 2 is shown, and the middle electroluminescent film 3 is with cast luminescent layer 1 3 and two Dielectric layers 43, 83 executed.
  • These two dielectric layers 43, 83 can alternatively also be arranged on both sides of the luminescent layer 1 3 and can furthermore be used for promoting adhesion and contain color-converting and / or color-filtering admixtures.
  • the adhesive layers 71, 72 of the upper and lower electroluminescent films 1, 2 can be omitted, and the back electrodes 31, 32 of the upper and lower electroluminescent films 1, 2 form the electrodes for the middle EL capacitor.
  • an electroluminescent film 1 shown in FIG. 4 has proven to be a particularly favorable compromise of reliable function and good manufacturability.
  • Three (possibly also two) similar electroluminescent films of the type shown, which differ only in their luminous color, are combined with one another to form a multicolor electroluminescent element according to the invention.
  • Electroluminescent film 1 essentially consists of a film substrate 51 made of PET or other plastic, onto which the electrode layer 21 is vapor-deposited or sputtered, a luminescent layer 11 and a transparent back electrode 31 applied by screen printing, which is laminated by means of the insulating film 91.
  • substrates are also conceivable which do not consist of a plastic film but of a ceramic material, for example glass.

Abstract

The invention relates to an electroluminescent film providing a particularly advantageous compromise between the safe functioning and simplified production thereof. The inventive polychromatic electroluminescent element consists of three similar electroluminescent films which contain dispersed electroluminophors and whose colors are not different from each other. The different colors are obtainable by an additional color mixture by means of a separate electric excitation of each electroluminescent film. Each of the films essentially comprises a support made of PET or other plastic material on which an electrode layer is vapour-deposited or cathode-sputtered, a luminous layer on which a rear transparent electrode is placed by serigraphy and laminated by means of an insulating foil.

Description

MEHRFARB-ELEKTROLUMINESZENZ-ELEMENT UND VERFAHREN ZU DESSEN HERSTELLUNG MULTICOLOR ELECTROLUMINESCENT ELEMENT AND METHOD FOR THE PRODUCTION THEREOF
Die vorliegende Erfindung betrifft ein Mehrfarb-Elektrolumineszenz-Element und ein Verfahren zu dessen Herstellung.The present invention relates to a multicolor electroluminescent element and a method for its production.
Die Elektrolumineszenztechnologie hat in jüngster Zeit zunehmend an Bedeutung gewonnen. Sie ermöglicht die Realisierung beinahe beliebig großer, blend- und schattenfreier, homogener Leuchtflächen. Dabei sind Leistungsaufnahme und Bautiefe (in der Größenordnung eines Millimeters und darunter) äußerst gering. Zu den typische Anwendung gehört neben der Hintergrundbeleuchtung von Flüssigkristall- Displays die Hinterleuchtung von transparenten Filmen, welche mit Beschriftungen und/oder Bildmotiven versehen sind.Electroluminescence technology has recently become increasingly important. It enables the realization of almost any size, glare-free and shadow-free, homogeneous illuminated surfaces. The power consumption and depth (in the order of a millimeter and below) are extremely low. In addition to the backlighting of liquid crystal displays, the typical application also includes the backlighting of transparent films which are provided with lettering and / or image motifs.
Unter Elektrolumineszenz (kurz: EL) versteht man die direkte Lumineszenzanregung von Leuchtpigmenten bzw. Luminophoren durch ein elektrisches Wechselfeld. Weitgehend durchgesetzt haben sich Elektrolumineszenz-Elemente (kurz: EL- Elemente) auf Basis der sogenannten Dickschichttechnologie mit anorganischen Leuchtpigmenten bzw. Luminophoren und Wechselspannungsanregung. Gegenüber Dünnfilm-EL-Elementen sind Dünnschicht-EL-Elemente weniger aufwendig und somit kostengünstiger in der Herstellung.Electroluminescence (short: EL) is the direct luminescence excitation of luminescent pigments or luminophores by an alternating electrical field. Electroluminescent elements (EL elements) based on the so-called thick-film technology with inorganic luminous pigments or luminophores and AC excitation have largely become established. Compared to thin-film EL elements, thin-film EL elements are less complex and therefore less expensive to manufacture.
Die Leuchtpigmente bzw. Luminophore sind in ein transparentes, organisches oder keramischen Bindemittel eingebettet. Ausgangsstoffe sind meist Zinksulfide, welche in Abhängigkeit von Dotierung bzw. Co-Dotierung und Präparationsvorgang unterschiedliche, relativ schmalbandige Emissionsspektren erzeugen. Der Schwerpunkt des Spektrums bestimmt die jeweilige Farbe des emittierten Lichtes.The luminous pigments or luminophores are embedded in a transparent, organic or ceramic binder. The starting materials are mostly zinc sulfides, which depend on the doping or co-doping and the preparation process generate different, relatively narrow-band emission spectra. The focus of the spectrum determines the respective color of the emitted light.
Das anregende Wechselspannungsfeld besitzt in der Regel eine Frequenz von einigen hundert Hertz, wobei der Effektivwert der Betriebsspannung häufig in einem Bereich von etwa 50 bis 1 50 Volt liegt. Durch Erhöhung der Spannung läßt sich in aller Regel eine höhere Leuchtdichte erzielen, welche üblicherweise in einem Bereich von ungefähr 50 bis etwa 200 Candela pro Quadratmeter liegt. Eine Frequenzerhöhung bewirkt in der Regel eine Farbverschiebung hin zu niedrigeren Wellenlängen. Beide Parameter müssen jedoch aufeinander abgestimmt werden, um einen gewünschten Leuchteindruck zu erzielen.The exciting AC voltage field generally has a frequency of a few hundred Hertz, the effective value of the operating voltage often being in a range from approximately 50 to 150 volts. By increasing the voltage, a higher luminance can generally be achieved, which is usually in a range from approximately 50 to approximately 200 candelas per square meter. Increasing the frequency usually causes a color shift towards lower wavelengths. However, both parameters must be coordinated to achieve a desired lighting impression.
Grundsätzlich bieten sich bei der Herstellung von Dickfilm-EL-Elementen mit Wechselspannungsanregung vor allem zwei Arten von Elektroden an. Zum einen sind dies im Vakuum auf Kunststoffolien gesputterte oder aufgedampfte Indium-Zinn-Oxid- Elektroden (Indium-Tin-Oxide, ITO). Sie sind sehr dünn (einige 100 Ä) und bieten den Vorteil einer hohen Transparenz bei einem relativ geringen Flächenwiderstand (ca. 60 bis 600 Ohm). Allerdings sind sie nicht auf strukturierte Oberflächen mit Stufen applizierbar, wenig verformbar und nicht auf im Vakuum leicht ausgasende Substrate applizierbar. Zum anderen können Druckpasten mit ITO oder ATO (Antimon-Tin-Oxide, Antimon-Zinn-Oxid) oder intrinsisch leitfähige transparente Polymerpasten verwendet werden. Bei einer Dicke von ca. 5 bis 20 μm bieten derartige Elektroden nur geringere Transparenz bei hohem Flächenwiderstand (bis 50 kOhm). Sie sind jedoch weitgehend beliebig strukturiert applizierbar, und zwar auch auf strukturierten Oberflächen. Ferner bieten sie eine relativ gute Laminierbarkeit sowie eingeschränkte Verformbarkeit.Basically, two types of electrodes are particularly suitable for the production of thick film EL elements with AC excitation. On the one hand, these are indium tin oxide electrodes (indium tin oxides, ITO) sputtered or vapor-deposited on plastic films. They are very thin (some 100 Å) and offer the advantage of high transparency with a relatively low surface resistance (approx. 60 to 600 ohms). However, they cannot be applied to structured surfaces with steps, are not deformable, and cannot be applied to substrates that easily outgas in a vacuum. On the other hand, printing pastes with ITO or ATO (antimony tin oxides, antimony tin oxide) or intrinsically conductive transparent polymer pastes can be used. With a thickness of approx. 5 to 20 μm, such electrodes only offer less transparency with a high surface resistance (up to 50 kOhm). However, they can largely be applied in any structure, even on structured surfaces. They also offer relatively good laminatability and limited deformability.
Die Lebensdauer eines EL-Elements ist begrenzt. Sie hängt vor allem von Höhe und Frequenz der angelegten Wechselspannung ab, darüberhinaus jedoch auch von Umwelteinflüssen insbesondere Einwirkung von Feuchtigkeit und UV-Strahlung. Angegeben wird die Lebensdauer eines EL-Elements üblicherweise als Halbwertszeit der Leuchtpigmente. Das ist die Zeit, nach welcher die Leuchdichte unter Einfluß des elektrischen Feldes bei unveränderten Betriebsbedingungen um die Hälfte des Anfangswertes abgenommen hat. In der Praxis geht die Leuchtdichte innerhalb etwa 2000 bis 3000 Betriebsstunden auf die Hälfte des ursprünglichen Werts zurück.The lifespan of an EL element is limited. It mainly depends on the level and frequency of the AC voltage applied, but also on environmental influences, in particular the effects of moisture and UV radiation. The service life of an EL element is usually given as the half-life of the luminescent pigments. This is the time after which the luminance under the influence of the electric field has decreased by half of the initial value under unchanged operating conditions. In practice, the luminance is roughly within 2000 to 3000 operating hours to half of the original value.
Die Emissionfarbe eines EL-Elements kann durch eine Vielzahl möglicher Maßnahmen an den gewünschten Farbeindruck angepasst werden. Hierzu gehören die Dotierung und Co-Dotierung der Leucht-Pigmente, die Mischung von zwei oder mehreren EL- Pigmenten, der Zusatz von einem oder mehreren organischen und/oder anorganischen farbkonvertierenden und/oder farbfiltemden Pigmenten, die Beschichtung des EL- Pigments mit organischen und/oder anorganischen farbkonvertierenden und/oder farbfiltemden Substanzen, die Beimengung von Farbstoffen in die Polymermatrix, in welcher die Leuchtpigmente dispergiert sind, sowie der Einbau einer farbkonvertierenden und/oder farbfiltemden Schicht bzw. Folie in den Aufbau des EL- Elements.The emission color of an EL element can be adapted to the desired color impression by a variety of possible measures. These include the doping and co-doping of the luminous pigments, the mixture of two or more EL pigments, the addition of one or more organic and / or inorganic color-converting and / or color-filtering pigments, the coating of the EL pigment with organic and / or inorganic color-converting and / or color-filtering substances, the incorporation of colorants into the polymer matrix in which the luminous pigments are dispersed, and the incorporation of a color-converting and / or color-filtering layer or film into the structure of the EL element.
Luminophore, welche ein reines Weiß emittieren, sind bisher nicht erhältlich. Aus diesem Grunde werden weißlich leuchtende EL-Elemente häufig mit Hilfe einer Mischung aus mindestens zwei Leuchtpigmenten hergestellt, deren Emissionen in ihrer Addition (annähernd) Weiß ergeben. Um reines Weiß zu erhalten ist üblicherweise die Verwendung eines organischen Leitlacks mit leichter Blaufärbung erforderlich. Allerdings verursacht die unterschiedliche Alterung der beiden Leuchtpigmente im Verlauf der Lebensdauer eine Veränderung des Farbeindrucks, der oft sehr störend oder unakzeptabel für die geplante Anwendung ist. Ferner existieren annähernd weißleuchtende Luminophore, welche jedoch toxische Zinkselenide enthalten und daher nur ungern Anwendung finden.Luminophores, which emit a pure white, are not yet available. For this reason, whitish-glowing EL elements are often produced using a mixture of at least two luminescent pigments, the emissions of which add up to (almost) white. In order to obtain pure white, it is usually necessary to use an organic conductive varnish with a light blue color. However, the different aging of the two luminescent pigments causes a change in the color impression over the course of the service life, which is often very disruptive or unacceptable for the planned application. Furthermore, there are almost white luminophores, which, however, contain toxic zinc selenides and are therefore reluctant to use them.
Häufig besteht das Bedürfnis nach EL-Elementen, welche mehrfarbig, d.h. inThere is often a need for EL elements which are multicolored, i.e. in
Abhängigkeit einer externen Steuerung wechselweise in unterschiedlichen Farben leuchten können. Entsprechende EL-Elemente werden als Mehrfarb- Elektrolumineszenz-Elemente bezeichnet.Depending on an external control can alternately shine in different colors. Corresponding EL elements are referred to as multicolor electroluminescent elements.
Mehrfarb-Elektrolumineszenz-Elemente sind unter anderem aus EP-A-104561 8 bekannt. Darin wird eine vielfarbige EL-Lampe beschrieben, bei welcher sich durch additive Farbmischung unterschiedliche Farben ergeben, indem mindestens zwei übereinander liegende, Leuchtpigmente enthaltende Elektrolumineszenz-Schichten mittels mindestens drei Elektrodenschichten entsprechend angesteuert werden. Die erste Elektrode wird hierfür mittels Aufdampfen von ITO auf ein PET-Substrat erzeugt, wohingegen alle weiteren Schichten, also auch alle weiteren Elektroden, mittels Siebdruck hergestellt werden.Multi-color electroluminescent elements are known, inter alia, from EP-A-104561 8. It describes a multi-colored EL lamp in which different colors result from additive color mixing, in that at least two electroluminescent layers lying one above the other and containing luminescent pigments are appropriately controlled by means of at least three electrode layers. The For this purpose, the first electrode is produced by vapor deposition of ITO on a PET substrate, whereas all further layers, that is to say also all further electrodes, are produced by means of screen printing.
Auch in EP-A-0998171 wird ein mehrlagiges EL-Element mit unterschiedlichen Mustern und vielen lumineszenten Farben beschrieben. Auch hier wird die erste transparente Elektrode mittels Aufdampfen oder Sputtern auf eine PET-Folie hergestellt. Alle weiteren Elektroden werden mittels Druck von optisch transparenten Pasten hergestellt.EP-A-0998171 also describes a multi-layer EL element with different patterns and many luminescent colors. Here, too, the first transparent electrode is produced by vapor deposition or sputtering onto a PET film. All other electrodes are produced by printing optically transparent pastes.
Aus EP-A-0973358 ist ein Mehrfarb-EL-Element bekannt, das mehrere lichtdurchlässige Elektrodenschichten und mehrere lumineszierende Schichten mit unterschiedlichen Farben aufweist. Auch gemäß dieser Druckschrift wird ein drucktechnischer Mehrlagenaufbau realisiert.A multi-color EL element is known from EP-A-0973358, which has a plurality of transparent electrode layers and a plurality of luminescent layers with different colors. According to this document too, a multi-layer printing technology is implemented.
Der Aufbau mit mehreren mittels Siebdruck hergestellten lumineszierenden Schichten, welchen alle aufgeführten bekannten Mehrfarb-EL-Elemente prinzipiell gemeinsam haben, ist mit einigen Problemen verbunden. Bei industriell üblichen und verfügbaren Elektroluminophoren muß üblicherweise mit Partikeldurchmessern von größer 20 Mikrometern, typischerweise zwischen 20 und 35 Mikrometern und einer breiten Partikelgrößenverteilung gerechnet werden. Daher sind Leuchtschichtdicken von 40 bis 60 μm üblich. Wenn nun derartige grobkörnige Pigmente in Siebdruckfarben dispergiert und mehrschichtig auf ein Trägersubstrat appliziert werden, dann ist verständlich, daß bei üblichen Füllgraden von 65 bis 75 Gewichtsprozent eine sehr unebene Oberfläche entsteht. Die Unebenheit wird zum einen durch die Streubreite der Partikelabmessungen bewirkt und zum anderen durch das Verdunsten von Lösemittel während des Trocknungsvorgangs. Zwar kann beispielsweise durch Verwendung von UV-härtbaren polymeren Bindemitteln und/oder . durch Verwendung von feinkörnigen Leuchtpigmenten und/oder Leuchtpigmenten mit enger Partikelgrößenverteilung die Unebenheit der Oberfläche jeder einzelnen Schicht reduziert werden. Bei mit nur einer Leuchtschicht versehenen und somit einfarbig emittierenden EL-Elementen sind diese Probleme somit beherrschbar. Bei Mehrlagenaufbauten addieren sich jedoch die Unebenheiten der einzelnen Schichten statistisch, so daß einen homogenen Leuchteindruck vermittelnde Mehrfarb-EL-Elemente in der Praxis nicht oder nur mit erheblichem Ausschuß auf die beschriebene Weise herstellbar sind.The construction with several luminescent layers produced by means of screen printing, which all the known multicolor EL elements listed have in common, has some problems. With industrially customary and available electroluminophores, particle diameters of greater than 20 micrometers, typically between 20 and 35 micrometers and a broad particle size distribution must usually be expected. Therefore, luminescent layer thicknesses of 40 to 60 μm are common. If such coarse-grained pigments are now dispersed in screen printing inks and applied in multiple layers to a carrier substrate, it is understandable that a very uneven surface is produced at the usual filling levels of 65 to 75 percent by weight. The unevenness is caused on the one hand by the spread of the particle dimensions and on the other hand by the evaporation of solvent during the drying process. This can be done, for example, by using UV-curable polymeric binders and / or. by using fine-grained luminescent pigments and / or luminescent pigments with a narrow particle size distribution, the unevenness of the surface of each individual layer can be reduced. In the case of EL elements provided with only one luminescent layer and thus emitting monochrome, these problems can thus be mastered. In the case of multi-layer structures, however, the unevenness of the individual layers add up statistically, so that in practice multi-color EL elements imparting a homogeneous lighting impression do not or only do so considerable committee can be produced in the manner described.
Ferner könnte zwar auch ein zusätzlicher einebnender Druckvorgang und/oder ein einebnender Laminiervorgang vorgenommen werden. Bei herkömmlichen EL- Elementen überwiegen die Nachteile derartiger Prozeßschritte jedoch deren Vorteile, da jede zusätzliche Schicht das eingeprägte elektrische Wechselfeld reduziert, und bei einem Laminiervorgang hervorstehende Pigmentpartikeln zwar in die darunter liegende polymere Schicht drücken können, jedoch ebenso gut die dielektrische Isolation durchstoßen und somit die Funktion des jeweiligen EL-Elementes sehr nachteilig beinflussen können.Furthermore, an additional leveling printing process and / or a leveling laminating process could also be carried out. In conventional EL elements, however, the disadvantages of such process steps outweigh their advantages, since each additional layer reduces the impressed alternating electrical field, and pigment particles that protrude during a lamination process can press into the polymer layer underneath, but also penetrate the dielectric insulation and thus the Can affect the function of the respective EL element very disadvantageously.
Zusätzlich zu diesen Problemen der Unebenheit kommt noch die Notwendigkeit, die einzelnen flächigen Elektroden zu üblicherweise seitlich angeordneten Anschlußflächen zu führen. Dies führt dazu, daß bei einem durch Siebdruck erzeugten mehrschichtigen Aufbau auf einem Substrat Schichthöhen bis über 100 μm überwunden werden müssen, was mit ITO- oder ATO-Siebdruckpasten durch Einfachdrucke nicht gelöst werden kann und durch Verwendung von sogenannten Bus-Bar Druckgebilden mittels Silberpasten zu einer weiteren Erhöhung der Unebenheit der Oberfläche führt. Denn bereits bei einer einzigen Leuchtschicht der oben genannten typischen Dicke müssen Isolationsschichten beziehungsweise Dielektrikumsschichten sehr sorgfältig über die Schichtkanten geführt werden, um dann auch eine Rückelektrode mit guten elektrisch leitenden Eigenschaften über eine derartige Schichtkante führen zu können.In addition to these unevenness problems, there is also the need to lead the individual flat electrodes to connection surfaces which are usually arranged laterally. This means that in the case of a multilayer structure produced by screen printing on a substrate, layer heights of up to over 100 μm have to be overcome, which cannot be solved with ITO or ATO screen printing pastes by simple printing and by using so-called bus bar printing structures using silver pastes leads to a further increase in the unevenness of the surface. Because even with a single luminescent layer of the above-mentioned typical thickness, insulation layers or dielectric layers must be guided very carefully over the layer edges in order to then be able to also guide a back electrode with good electrically conductive properties over such a layer edge.
Somit ist die gesamte Herstellung herkömmlicher Mehrfarb-EL-Elemente, insbesondere jedoch die Herstellung der elektrischen Beschaltung beziehungsweise der Anschlüsse diverser Felder bei segmentartig aufgebauten Leuchtschichten äußerst schwierig zu beherrschen und sehr fehleranfällig.Thus, the entire production of conventional multi-color EL elements, in particular, however, the production of the electrical circuitry or the connections of various fields in segment-like light layers is extremely difficult to master and very prone to errors.
Angesichts der geschilderten Problematik ist es Aufgabe der vorliegenden Erfindung, ein Mehrfarb-Elektrolumineszenz-Element zu schaffen, das in Abhängigkeit der elektrischen Ansteuerung unterschiedliche Leuchtfarben annehmen kann und dennoch mit vertretbarem Aufwand in hoher Qualität herstellbar ist. Hiermit verbunden ist die Aufgabe, ein geeignetes Herstellungsverfahren für Mehrfarb-EL-Elemente bereitzustellen, welches hohe Produktqualität bei geringem Ausschuß ermöglicht. Gemäß einem Aspekt der vorliegenden Erfindung wird diese Aufgabe durch eine Mehrfarb-Elektrolumineszenz-Element gemäß Patentanspruch 1 gelöst. Entgegen dem Stand der Technik, wonach Mehrfarb-Elektrolumineszenz-Elemente als mehrschichtiger Siebdruckaufbau auf einer Folie ausgeführt sind, ist das erfindungsgemäße Mehrfarb-Elektrolumineszenz-Eiement aus mindestens zwei Elektrolumineszenzfolien mit jeweils einer Leuchtschicht aufgebaut. Unter einer Elektrolumineszenzfolie ist dabei ein zusammenhängender Folienkörper mit einer gewissen Formstabilität zu verstehen, welche daher rührt, daß die Leuchtschicht der Elektrolumineszenzfolie auf ein stabiles Foliensubstrat (als Träger) aufgebracht ist und/oder selbst aus einer vorzugsweise gegossenen Folie besteht, in deren Matrix die dispergierten Luminophoren eingelagert sind. Dies hat den entscheidenden Vorteil, daß bei der Herstellung jede Elektrolumineszenzfolie separat mit der bzw. den benötigten Elektrodenschicht bzw. -schichten versehen werden kann, und nicht der Gesamtaufbau sequentiell gewissermaßen "von unten nach oben" entstehen muß. Die oben geschilderten Probleme mit der Verschaltung der Elektroden entfallen so weitestgehend. Insbesondere können die Anschlüsse der Elektroden auf den einzelnen Elektrolumineszenzfolien separat gemäß beherrschbaren, für herkömmliche einfarbige Elektrolumineszenz-Elemente üblichen Techniken gestaltet sein.In view of the problems outlined, it is an object of the present invention to provide a multicolor electroluminescent element which, depending on the electrical control, can assume different luminous colors and yet can be produced in a high quality with reasonable effort. Associated with this is the task of providing a suitable manufacturing process for multi-color EL elements, which enables high product quality with little waste. According to one aspect of the present invention, this object is achieved by a multicolor electroluminescent element according to claim 1. Contrary to the prior art, according to which multicolor electroluminescent elements are designed as a multilayer screen printing structure on a film, the multicolor electroluminescent element according to the invention is constructed from at least two electroluminescent films, each with a luminescent layer. An electroluminescent film is to be understood as a coherent film body with a certain dimensional stability, which stems from the fact that the luminous layer of the electroluminescent film is applied to a stable film substrate (as a support) and / or itself consists of a preferably cast film, in the matrix of which the dispersed Luminophores are stored. This has the decisive advantage that each electroluminescent film can be provided separately with the required electrode layer or layers during manufacture, and the overall structure does not have to be created sequentially, so to speak, "from bottom to top". The problems described above with the wiring of the electrodes are largely eliminated. In particular, the connections of the electrodes on the individual electroluminescent foils can be designed separately according to controllable techniques that are customary for conventional single-color electroluminescent elements.
Die Erzeugung unterschiedlicher Farben entsteht durch additive Farbmischung, indem jede, jeweils in einer unterschiedlichen Farbe emittierende, Leuchtschicht durch jeweils ein separat gesteuertes elektrisches Wechselfeld unterschiedlich angeregt wird. Bei drei Elektrolumineszenzfolien in den Farben Rot, Grün und Blau läßt sich so das gesamte Farbspektrum einschließlich Weiß bei entsprechender Ansteuerung darstellen.Different colors are generated by additive color mixing, in that each luminescent layer, each emitting in a different color, is excited differently by a separately controlled alternating electric field. With three electroluminescent foils in the colors red, green and blue, the entire color spectrum including white can be displayed with appropriate control.
Bevorzugte Ausführungsformen der vorliegenden Erfindung sind gemäß den Patentansprüchen 2-22 gestaltet.Preferred embodiments of the present invention are designed according to claims 2-22.
Gemäß einem weiteren Aspekt der vorliegenden Erfindung wird die Aufgabe durch ein Verfahren zur Herstellung eines Mehrfarb-Elektrolumineszenz-Elements gemäß Patentanspruch 23 gelöst. Entgegen dem Stand der Technik werden dabei nicht alle einzelnen Schichten des EL-Elements sequentiell, gewissermaßen "von unten nach oben", drucktechnisch übereinander aufgebracht, sondern mindestens zwei vorgefertigte Elektrolumineszenzfolien, beispielsweise durch Laminieren, zusammengesetzt. Die oben geschilderten Probleme mit der Verschaltung der Elektroden entfallen so weitestgehend. Insbesondere können die Anschlüsse der Elektroden auf den einzelnen Elektrolumineszenzfolien vor dem Zusammenfügen separat gemäß beherrschbaren, für herkömmliche einfarbige Elektrolumineszenz- Elemente üblichen Techniken hergestellt werden.According to a further aspect of the present invention, the object is achieved by a method for producing a multicolor electroluminescent element according to claim 23. Contrary to the state of the art, not all individual layers of the EL element are applied sequentially, so to speak "from bottom to top", one above the other in terms of printing technology, but at least two prefabricated electroluminescent films, for example by lamination, assembled. The problems described above with the wiring of the electrodes are largely eliminated. In particular, the connections of the electrodes on the individual electroluminescent foils can be produced separately prior to assembly according to controllable techniques that are common for conventional single-color electroluminescent elements.
Bevorzugte Ausführungsformen des erfindungsgemäßen Verfahrens sind gemäß den Patentansprüchen 24-26 ausgestaltet.Preferred embodiments of the method according to the invention are designed in accordance with patent claims 24-26.
Anhand der zugehörigen Zeichnungen werden Beispiele bevorzugter Ausführungsformen der vorliegenden Erfindung näher erläutert. Die Zeichnungen sind dabei rein schematische und nicht maßstäbliche Schnittdarstellungen, insbesondere sind Schichtdicken aus Anschaulichkeitsgründen stark vergrößert. Der Bereich der Elektrodenanschlüsse ist jeweils nicht dargestellt.Examples of preferred embodiments of the present invention are explained in more detail with reference to the accompanying drawings. The drawings are purely schematic and not to scale sectional views, in particular layer thicknesses have been greatly enlarged for reasons of clarity. The area of the electrode connections is not shown in each case.
Fig. 1 a bis 1 k zeigen verschiedene prinzipielle Anordnungsvarianten im Schichtaufbau erfindungsgemäßer Mehrfarb-Elektrolumineszenz-Elemente, jeweils einmal vor Zusammenfügen der Elektrolumineszenzfolien und danach. Eventuell zusätzlich im Aufbau enthaltene Isolier- oder Haftvermittlerschichten sind nicht dargestellt.1 a to 1 k show different basic arrangement variants in the layer structure of multicolor electroluminescent elements according to the invention, in each case once before joining the electroluminescent films and afterwards. Any additional insulating or adhesion promoter layers contained in the structure are not shown.
Fig. 2 zeigt exemplarisch ein aus drei Elektrolumineszenzfolien zusammengesetztes Mehrfarb-Elektrolumineszenz-Element, ~ jeweils vor Zusammenfügen der Elektrolumineszenzfolien und danach, wobei jede Elektrolumineszenzfolie ein stabiles Foliensubstrat aufweist.FIG. 2 shows an example of a multicolor electroluminescent element composed of three electroluminescent foils, in each case before the electroluminescent foils are joined together and afterwards, each electroluminescent foil having a stable foil substrate.
Fig. 3 zeigt exemplarisch ein aus drei Elektrolumineszenzfolien zusammengesetztes Mehrfarb-Elektrolumineszenz-Element, jeweils vor Zusam- menfügen der Elektrolumineszenzfolien und danach. Dabei ist der Aufbau ähnlich ausgeführt wie in Fig. 2, die mittlere Elektrolumineszenzfolie weist jedoch kein Foliensubstrat auf, sondern deren Folieneigenschaft rührt von der gegossenen Matrix der Leuchtschicht her. Fig.4 zeigt den Aufbau einer Elektrolumineszenzfolie eines besonders bevorzugten erfindungsgemäßen Mehrfarb-Elektrolumineszenz- Elements. Drei (ggf. auch zwei) gleichartige, sich nur durch ihre Leuchtfarbe unterscheidende Elektrolumineszenzfolien der dargestellten Art werden dabei miteinander kombiniert.3 shows an example of a multicolor electroluminescent element composed of three electroluminescent films, in each case before the electroluminescent films are joined together and afterwards. The structure is similar to that in FIG. 2, but the middle electroluminescent film does not have a film substrate, but its film property stems from the cast matrix of the luminescent layer. 4 shows the structure of an electroluminescent film of a particularly preferred multicolor electroluminescent element according to the invention. Three (possibly also two) similar electroluminescent films of the type shown, which differ only in their luminous color, are combined with one another.
In den Figuren 1 a bis 1 k sind exemplarisch verschiedene grundsätzlich mögliche Anordnungsvarianten des Schichtaufbaus erfindungsgemäßer Mehrfarb- Elektrolumineszenz-Elemente dargestellt. Dabei zeigt die jeweils linke Teildarstellung die Elektrolumineszenzfolien 1 , 2, 3 vor dem Zusammenfügen, und die rechte Teildarstellung den Schichtaufbau des danach entstandenen Mehrfarb- Elektrolumineszenz-Elements. Zusätzlich können weitere Schichten, insbesondere Dielektrikums- bzw. Isolier- oder Haftvermittlerschichten im jeweiligen Aufbau enthalten sein, welche der Übersichtlichkeit halber nicht dargestellt sind. Die Haftvermittlerschichten dienen zur Verbindung der Elektrolumineszenzfolien miteinander. Auch (nicht dargestellte) farbfiltemde oder farbumwandelnde Schichten sowie Aufdrucke können enthalten sein, um einen gewünschten Farbeindruck zu erzeugen. Diese können auch nur teilflächig vorgesehen sein um gewisse grafische Gestaltungen zu erzielen.FIGS. 1 a to 1 k show examples of various fundamentally possible arrangement variants of the layer structure of multicolor electroluminescent elements according to the invention. The partial representation on the left in each case shows the electroluminescent films 1, 2, 3 before the assembly, and the partial representation on the right shows the layer structure of the multicolor electroluminescent element which has subsequently formed. In addition, further layers, in particular dielectric or insulating or adhesion promoter layers can be contained in the respective structure, which are not shown for the sake of clarity. The adhesion promoter layers serve to connect the electroluminescent films to one another. Color filtering or color converting layers and imprints (not shown) can also be included in order to produce a desired color impression. These can also be provided only over part of the area in order to achieve certain graphic designs.
Jede Elektrolumineszenzfolie 1 , 2, 3 weist eine Leuchtschicht 1 1 , 1 2, 1 3 mit dispersen Elektroluminophoren 4 auf, wobei es sich bevorzugt um gegossene Folien handelt, in deren Folienmatrix 6 die Elektroluminophoren 4 eingelagert sind. Möglich sind auch extrudierte Folien, diese sind jedoch aufgrund einer oft ungünstigeren Verteilung der Elektroluminophoren weniger vorteilhaft. Insbesondere die Darstellung der Elektroluminophore 4 ist rein schematisch aufzufassen. In der Praxis bemüht man sich um möglichst der Kugelform angenäherte Partikeln. Elektroluminophore sind in der Regel empfindlich gegen Feuchtigkeitseinwirkung. Darum werden in den Schichtaufbau herkömmlicher Elektrolumineszenzelemente meist zusätzliche Schichten integriert, welche die Funktion einer Feuchtigkeitssperre bzw. Dampfsperre übernehmen. Auch in den Aufbau erfindungsgemäßer Mehrfarb-Elektrolumineszenz- Elements können entsprechende Schichten integriert werden. Diese können jedoch insbesondere dann weitgehend entfallen, wenn mikroverkapseite Elektroluminophore 4 verwendet werden. Die Mikroverkapselung ist üblicherweise oxidisch oder nitridisch, allerdings ist auch eine organische Mikroverkapselung oder eine diamantartige Carbonverkapselung ("diamond-like carbon") denkbar.Each electroluminescent film 1, 2, 3 has a luminescent layer 1 1, 1 2, 1 3 with disperse electroluminophores 4, which are preferably cast films in whose film matrix 6 the electroluminophores 4 are embedded. Extruded foils are also possible, but these are less advantageous due to the often less favorable distribution of the electroluminophores. In particular, the representation of the electroluminophores 4 is to be understood purely schematically. In practice, efforts are made to obtain particles that approximate the spherical shape. Electroluminophores are usually sensitive to the effects of moisture. For this reason, additional layers are usually integrated into the layer structure of conventional electroluminescent elements, which take on the function of a moisture barrier or vapor barrier. Corresponding layers can also be integrated into the structure of the multicolor electroluminescent element according to the invention. However, these can largely be eliminated, in particular, if micro-encapsulated electroluminophores 4 are used. The microencapsulation is usually oxidic or nitridic, however, organic microencapsulation or diamond-like carbon encapsulation ("diamond-like carbon") is also conceivable.
Einen besonders einfachen Aufbau eines erfindungsgemäßen Mehrfarb- Elektrolumineszenz-Elements zeigt Fig. 1 a. Die erste Elektrolumineszenzfolie 1 weist eine Qe nach Anwendungsfall weitgehende transparente oder reflektierend opake) Elektrodenschicht 21 und eine weitgehend transparente Rückelektrodenschicht 31 auf. Zusammen mit der dazwischen angeordneten ersten Leuchtschicht 1 1 bilden diese einen ersten ELektrolumineszenzkondensator. Die zur zweiten Elektrolumineszenzfolie gehörende zweite Leuchtschicht 1 2 ist mit nur einer weitgehend transparenten Elektrodenschicht 22 versehen. Im fertig zusammengebauten Mehrfarb- Elektrolumineszenz-Element bilden die Elektrodenschicht 22 und die zweite Leuchtschicht 1 2 zusammen mit der Rückelektrodenschicht 31 der ersten Elektrolumineszenzfolie 1 einen zweiten Elektrolumineszenzkondensator. Dadurch, daß die Elektroluminophoren 4 der ersten Leuchtschicht 1 1 und zweiten Leuchtschicht 1 2 in jeweils einer unterschiedlichen Farbe leuchten, lassen sich durch additive Farbmischung unterschiedliche Leuchtfarben des Mehrfarb-Elektrolumineszenz- Elements erzielen, indem die elektrischen Wechselfelder zwischen den beiden Elektrolumineszenzkondensatoren unterschiedlich eingestellt werden. Selbstredend ist dies nur dann möglich, wenn zumindest die zweite Leuchtschicht 1 2 weitgehend transparent ist. Bei geeignet ausgewählten Elektroluminophoren 4, beispielsweise blauen Elektroluminophoren 4 in der ersten Leuchtschicht 1 1 und orangefarbenen Elektroluminophoren 4 in der zweiten Leuchtschicht 1 2 und geeigneter elektrischer Ansteuerung kann so auch weißes Leuchten bewirkt werden.1 a shows a particularly simple construction of a multicolor electroluminescent element according to the invention. The first electroluminescent film 1 has a Qe, largely transparent or reflectively opaque) electrode layer 21 and a largely transparent back electrode layer 31, depending on the application. Together with the first luminous layer 11 arranged in between, they form a first electroluminescent capacitor. The second luminescent layer 1 2 belonging to the second electroluminescent film is provided with only one largely transparent electrode layer 22. In the fully assembled multicolor electroluminescent element, the electrode layer 22 and the second luminescent layer 12 together with the back electrode layer 31 of the first electroluminescent film 1 form a second electroluminescent capacitor. Characterized in that the electroluminophores 4 of the first luminescent layer 1 1 and second luminescent layer 1 2 shine in a different color, additive color mixing enables different luminescent colors of the multicolor electroluminescent element to be achieved by the electrical alternating fields between the two electroluminescent capacitors being set differently. Of course, this is only possible if at least the second luminescent layer 1 2 is largely transparent. With suitably selected electroluminophores 4, for example blue electroluminophores 4 in the first luminescent layer 11 and orange-colored electroluminophores 4 in the second luminescent layer 1 2 and suitable electrical control, white lighting can also be brought about in this way.
Das in Fig. 1 b dargestellte Mehrfarb-Elektrolumineszenz-Element ist weitgehend wie das Mehrfarb-Elektrolumineszenz-Element in Fig. 1 a aufgebaut. Allerdings weist hier zur Erzielung einer besseren Steuerbarkeit auch die zweite Leuchtschicht 1 2 eine eigene Rückelektrodenschicht 32 auf. Rückelektrodenschicht 32 und Elektrodenschicht 22 können dabei auch vertauscht sein. Der in Fig. 1 b dargestellte Aufbau macht es erforderlich, an der Verbindungsfläche zwischen erster Elektrolumineszenzfolie 1 und zweiter Elektrolumineszenzfolie 2 eine isolierende Schicht 42 vorzusehen, um Kurzschlüsse zu vermeiden. in Fig. 1 c und 1 d ist jeweils ein Mehrfarb-Elektrolumineszenz-Element mit drei Elektrolumineszenzfolien 1 , 2, 3 dargestellt. Jede der Leuchtschichten 1 1 , 12, 13 emittiert aufgrund unterschiedlicher Elektroluminophoren 4 mit einer unterschiedlichen Farbe, so daß die mittels additiver Farbmischung erzielbare Farbenvielfalt noch größer ist. Bei der Verwendung roter, blauer und grüner (RGB) Elektroluminophoren 4 ist prinzipiell die Darstellung des gesamten Farbspektrums möglich. Rote Elektroluminophore werden jedoch üblicherweise nicht eingesetzt, da sie Cadmium enthalten, welches toxisch ist. Eine rote Leuchtfarbe läßt sich jedoch auch mittel farbkonvertierenden oder farbfiltemden Substanzen erreichen. Die für einen "dreifarbigen" Aufbau mindestens erforderlichen vier Elektroden können vor dem Zusammenfügen unterschiedlich verteilt sein. Neben Elektrodenschicht, 21 und Rückelektrodenschicht 31 auf der ersten Elektrolumineszenzfolie 1 kann auch auf der zweiten Elektrolumineszenzfolie 2 je eine Elektrodenschicht 22 und Rückelektrodenschicht 32 angeordnet sein, wie in Fig. 1 c dargestellt, während für die dritte, mittlere Elektrolumineszenzfolie 3 nicht unbedingt eine eigene Elektrodenschicht benötigt wird. Oder aber die zweite Elektrolumineszenzfolie 2 weist keine Rückelektrodenschicht 32 auf, dafür ist die dritte Elektrolumineszenzfolie 3 mit einer eigenen Elektrodenschicht 23 versehen.The multicolor electroluminescent element shown in FIG. 1b is largely constructed like the multicolor electroluminescent element in FIG. 1a. However, in order to achieve better controllability, the second luminescent layer 1 2 also has its own back electrode layer 32. Back electrode layer 32 and electrode layer 22 can also be interchanged. The structure shown in FIG. 1b makes it necessary to provide an insulating layer 42 on the connection surface between the first electroluminescent film 1 and the second electroluminescent film 2 in order to avoid short circuits. 1 c and 1 d each show a multicolor electroluminescent element with three electroluminescent films 1, 2, 3. Each of the luminescent layers 11, 12, 13 emits with a different color due to different electroluminophores 4, so that the variety of colors that can be achieved by means of additive color mixing is even greater. When using red, blue and green (RGB) electroluminophores 4, it is possible in principle to display the entire color spectrum. However, red electroluminophores are usually not used because they contain cadmium, which is toxic. However, a red fluorescent color can also be achieved by means of color-converting or color-filtering substances. The at least four electrodes required for a "three-color" structure can be distributed differently before being joined together. In addition to the electrode layer 21 and back electrode layer 31 on the first electroluminescent film 1, an electrode layer 22 and a back electrode layer 32 can also be arranged on the second electroluminescent film 2, as shown in FIG. 1 c, while the third, middle electroluminescent film 3 does not necessarily have its own electrode layer is needed. Or the second electroluminescent film 2 does not have a back electrode layer 32, for this the third electroluminescent film 3 is provided with its own electrode layer 23.
Der in Fig. 1 e bzw. Fig. 1 f dargestellte Aufbau entspricht im wesentlichen dem in Fig. 1 a gezeigten Aufbau. Hier weist allerdings die erste Elektrolumineszenzfolie 1 (Fig. 1 e) oder die zweite Elektrolumineszenzfolie 2 (Fig. 1 f) ein stabiles Foliensubstrat 51 , 52 auf. Die entsprechende Elektrodenschicht 21 , 22, vorzugsweise aus ITO (Indium-Zinn-Oxid), kann dann auf das Foliensubstrat 51 , 52 beispielsweise vakuumtechnisch aufgesputtert oder aufgedampft sein. Das transparente oder zumindest teiltransparente Foliensubstrat 51 , 52 besteht aus einer polymeren oder copolymeren Folie, beispielsweise aus Polycarbonat (PC) oder Polyalkylenterephthalaten oder Polyamid (PA) oder Polyacrylat oder Polymethacrylat oder Polymethylmethacrylat (PMMA) oder Polyurethan (PUR) oder Polyoxymethylen (POM) oder ABS- Pfropf polymerisaten oder Polyolefinen, wie Polyethylen (PE) oder Polypropylen (PP), oder Polystyrol (PS) oder Polyvinylchlorid (PVC) oder Polyimid (Pl) oder Polyetherimiden (PEI) oder Polyether oder Polyetherketone (PEK) oder Polyvinylfluorid (PVF) oder Polyvinylidenfluorid (PVdF) oder dergleichen Folien, die im optisch sichtbaren Wellenlängenbereich hohe Transparenz aufweisen. Besonders geeignet sind Folien aus Polyethylenterephtalat (PET). Da das Foliensubstrat 51 , 52 als stabilisierender Träger fungiert, benötigt die entsprechende Leuchtschicht 1 1 , 1 2 nicht mehr unbedingt besondere Eigenstabilität, so daß die Leuchtschicht 1 1 , 12 nicht nur als (gegossene) Folie, sondern stattdessen auch als Siebdruckschicht oder dergleichen ausgeführt sein kann.The structure shown in Fig. 1 e or Fig. 1 f corresponds essentially to the structure shown in Fig. 1 a. Here, however, the first electroluminescent film 1 (FIG. 1e) or the second electroluminescent film 2 (FIG. 1f) has a stable film substrate 51, 52. The corresponding electrode layer 21, 22, preferably made of ITO (indium tin oxide), can then be sputtered or vapor-deposited onto the film substrate 51, 52, for example by vacuum technology. The transparent or at least partially transparent film substrate 51, 52 consists of a polymeric or copolymeric film, for example made of polycarbonate (PC) or polyalkylene terephthalates or polyamide (PA) or polyacrylate or polymethacrylate or polymethyl methacrylate (PMMA) or polyurethane (PUR) or polyoxymethylene (POM) or ABS graft polymers or polyolefins, such as polyethylene (PE) or polypropylene (PP), or polystyrene (PS) or polyvinyl chloride (PVC) or polyimide (Pl) or polyetherimides (PEI) or polyether or polyether ketones (PEK) or polyvinyl fluoride (PVF) or polyvinylidene fluoride (PVdF) or similar films which have high transparency in the optically visible wavelength range. Especially Films made of polyethylene terephthalate (PET) are suitable. Since the film substrate 51, 52 acts as a stabilizing support, the corresponding luminescent layer 1 1, 1 2 no longer necessarily requires particular intrinsic stability, so that the luminescent layer 1 1, 12 is not only designed as a (cast) film, but instead also as a screen printing layer or the like can be.
Fig. I g und Fig. 1 h zeigen einen Fig. 1 c bzw. Fig. 1 d entsprechenden Aufbau, wobei die erste Elektrolumineszenzfolie 1 ein Foliensubstrat 51 der oben beschriebenen Art aufweist.1 g and 1 h show a structure corresponding to FIG. 1 c and FIG. 1 d, the first electroluminescent film 1 having a film substrate 51 of the type described above.
Der Aufbau des in Fig. 1 i dargestellten Mehrfarb-Elektrolumineszenz-Elements entspricht weitgehend dem in Fig. 1 b dargestellten Aufbau, wobei beide Elektrolumineszenzfolien 1 , 2 ein Foliensubstrat 51 , 52 der oben beschriebenen Art aufweisen. So lassen sich zwei fast identische, sich nur durch die Farbe ihrer Elektroluminophoren 4 unterscheidende Elektrolumineszenzfolien 1 , 2 verwenden. Durch Hinzunahme einer dritten, sich nur durch ihre Leuchtfarbe unterscheidenden Elektrolumineszenzfolie (nicht dargestellt) ist auch eine RGB-Anordnung zur Darstellung des gesamten Farbspektrums möglich.The structure of the multicolor electroluminescent element shown in FIG. 1 i largely corresponds to the structure shown in FIG. 1 b, wherein both electroluminescent films 1, 2 have a film substrate 51, 52 of the type described above. It is thus possible to use two almost identical electroluminescent films 1, 2, which differ only in the color of their electroluminophores 4. By adding a third electroluminescent film (not shown) that differs only in its luminescent color, an RGB arrangement for displaying the entire color spectrum is also possible.
Fig. 1j und Fig. 1 k zeigen einen Fig. I g bzw. Fig. 1 h entsprechenden Aufbau, wobei neben der ersten Elektrolumineszenzfolie 1 auch die zweite Elektrolumineszenzfolie 2 ein Foliensubstrat 52 der oben beschriebenen Art aufweist.1j and 1k show a structure corresponding to FIG. 1g and FIG. 1h, wherein in addition to the first electroluminescent film 1, the second electroluminescent film 2 also has a film substrate 52 of the type described above.
Neben den in Fig. 1 a bis Fig. 1 k dargestellten Varianten sind auch hieraus gebildete "Mischformen" und weitere erfindungsgemäße Anordnungen möglich.In addition to the variants shown in FIGS. 1 a to 1 k, “mixed forms” formed therefrom and further arrangements according to the invention are also possible.
Die (Rück-)Elektrodenschichten 21 , 22, 23, 31 , 32, 33 werden in der Regel über den gesamten Rand der Elektrodenfläche mittels ringförmig um die Elektrodenfläche herumgeführte Leiter kontaktiert. Dies hat den Vorteil, daß sich trotz des nicht unbeachtlichen Flächenwiderstandes der dünnen Elektrodenschichten 21 , 22, 23, 31 , 32, 33 keine allzugroßen Potentialunterschiede über die Fläche ausbilden, und daher die homogene Leuchtwirkung unterstützt wird. Ferner können einzelne Elektrolumineszenzfolien 1 , 2, 3, ferner aber auch das gesamte Mehrfarb- Elektrolumineszenz-Element segmentartig aufgeteilt sein, wobei einzelne Segmente jeweils separat elektrisch kontaktiert sind und auch separat angesteuert werden können, um als Segmentanzeige zur Darstellung unterschiedlicher Muster bzw. Grafiken oder aber auch Schriftzeichen einsetzbar zu sein.The (rear) electrode layers 21, 22, 23, 31, 32, 33 are generally contacted over the entire edge of the electrode surface by means of conductors which are guided in a ring around the electrode surface. This has the advantage that, despite the not inconsiderable surface resistance of the thin electrode layers 21, 22, 23, 31, 32, 33, there are no excessively large potential differences across the surface, and therefore the homogeneous lighting effect is supported. Furthermore, individual electroluminescent films 1, 2, 3, but also the entire multicolor electroluminescent element can be divided into segments, with individual segments are each separately electrically contacted and can also be controlled separately in order to be used as a segment display for displaying different patterns or graphics or else characters.
Eine etwas detailliertere Darstellung eines "dreifarbig" (RGB) emittierenden Mehrfarb-Elektrolumineszenz-Elements ist in Fig. 2 abgebildet. Auch hier zeigt die linke Teildarstellung die Elektrolumineszenzfolien 1 , 2, 3 vor dem Zusammenfügen, und die rechte Teildarstellung den Schichtaufbau des danach entstandenen Mehrfarb- Elektrolumineszenz-Elements.A somewhat more detailed illustration of a "three-color" (RGB) emitting multicolor electroluminescent element is shown in FIG. 2. Here, too, the left partial illustration shows the electroluminescent films 1, 2, 3 before the assembly, and the right partial illustration shows the layer structure of the multicolor electroluminescent element which has subsequently been created.
Auf der ersten, untersten Elektrolumineszenzfolie 1 ist eine Haftklebstoffschicht 7 zur vereinfachten Anbringung auf einer Unterlage vorgesehen. Ansonsten sind die einzelnen Elektrolumineszenzfolien 1 , 2, 3 weitestgehend gleich und im wesentlichen der Figur 1 i entsprechend aufgebaut (lediglich die Leuchtschichten 1 1 , 1 2, 1 3 emittieren selbstredend in jeweils einer anderen Farbe, zweckmäßigerweise Rot, Blau und Grün):A pressure-sensitive adhesive layer 7 is provided on the first, lowermost electroluminescent film 1 for simplified attachment to a base. Otherwise, the individual electroluminescent films 1, 2, 3 are largely the same and essentially constructed in accordance with FIG. 1 i (only the luminescent layers 1 1, 1 2, 1 3 naturally emit in a different color, expediently red, blue and green):
Eine als Foliensubstrat 51 , 52, 53 dienende Polyesterfolie 51 , 52, 53, beispielsweise von einer Dicke zwischen 100 μm und 250 μm, vorzugsweise zwischen 1 25 μm und 175 μm, ist mit einer als Elektrodenschicht 21 , 22, 23 dienenden elektrisch leitfähigen und weitgehend transparenten Beschichtung in Form einer Indium-Zinn- Oxid (ITO) Beschichtung 21 , 22, 23 versehen. Diese Elektrodenschicht 21 , 22, 23 kann konventionell mittels Schneid-Ritz-Plotter oder mittels Ätzen oder durch Lasereinwirkung gemäß der gewünschten Ausbildung mehrerer Segmente und der entsprechenden Anschlußverdrahtung strukturiert sein oder kann ganzflächig verwendet werden. Möglich ist ferner, die Elektrodenschicht 21 , 22, 23 bei der fertigen oder halbfertigen Elektrolumineszenzfolie 1 , 2, 3 oder gar dem fertigen oder halbfertigen Mehrfarb-Elektrolumineszenzelement mittels Laserstrahl sozusagen innenliegend teilweise zu ablatieren und somit zu strukturieren beziehungsweise konturieren.A polyester film 51, 52, 53 serving as film substrate 51, 52, 53, for example with a thickness between 100 μm and 250 μm, preferably between 1 25 μm and 175 μm, is provided with an electrically conductive and. Serving as electrode layer 21, 22, 23 largely transparent coating in the form of an indium tin oxide (ITO) coating 21, 22, 23 provided. This electrode layer 21, 22, 23 can be structured conventionally by means of a scratch-cut plotter or by means of etching or by laser action in accordance with the desired formation of several segments and the corresponding connection wiring, or can be used over the entire area. It is also possible to partially ablate the electrode layer 21, 22, 23 in the finished or semi-finished electroluminescent film 1, 2, 3 or even in the finished or semi-finished multi-color electroluminescent element, so to speak, to structure and thus contour it.
Ferner können sogenannte Bus-bars, also besser leitfähige VerdrahtungselementeFurthermore, so-called bus bars, i.e. more conductive wiring elements
(nicht dargestellt) mittels beispielsweise Siebdruck und/oder Verwendung von(not shown) by means of, for example, screen printing and / or using
Silberleitpasten und/oder Kupferleitpasten und/oder Carbonleitpasten hergestellt werden. Bei der Herstellung wird die jeweilige Leuchtschicht 1 1 , 1 , 1 3 bevorzugt mittels Siebdruck in Form von in einer transparenten Polymermatrix 6 dispergierten Elektroluminophoren 4 bzw. EL-Pigmenten 4 in der gewünschten grafischen Ausbildung hergestellt. Je nach gewünschter Emissionsfarbe werden geeignete EL- Pigmente 4 oder EL-Pigment-Mischungen 4 verwendet und/oder es werden geeignete farbkonvertierende und/oder farbfiltemde Substanzen dem Bindemittel der Matrix 6 beigegeben. Grundsätzlich können derartige farbkonvertierende und/oder farbfiltemde Effekte auch dadurch bewirkt werden, daß mittels eines weiteren Druckes auf die Oberseite des Substrates 51 , 52, 53 eine entsprechende Schicht 61 , 62, 63 aufgetragen und/oder eine entsprechende Folie laminiert wird.Silver conductive pastes and / or copper conductive pastes and / or carbon conductive pastes are produced. During production, the respective luminescent layer 11, 1, 13 is preferably produced by screen printing in the form of electroluminophores 4 or EL pigments 4 dispersed in a transparent polymer matrix 6 in the desired graphic configuration. Depending on the desired emission color, suitable EL pigments 4 or EL pigment mixtures 4 are used and / or suitable color-converting and / or color-filtering substances are added to the binder of the matrix 6. In principle, such color-converting and / or color-filtering effects can also be brought about by applying a corresponding layer 61, 62, 63 to the top of the substrate 51, 52, 53 and / or laminating a corresponding film by means of further printing.
Es kann zweckmäßig sein, auf die Leuchtschicht 1 1 , 1 2, 1 3 eine Dielektrikumsschicht 41 , 42, 43 aufzubringen. Im Falle der Verwendung eines Siebdruckprozesses wird vorteilhafterweise eine zweite Dielektrikumsschicht 81 , 82, 83 aufgebracht, wodurch kleine Fehlstellen und/oder Mikrolufteinschlüsse überdeckt werden und die Isolationseigenschaft verbessert wird.It may be expedient to apply a dielectric layer 41, 42, 43 to the luminescent layer 1 1, 1 2, 1 3. If a screen printing process is used, a second dielectric layer 81, 82, 83 is advantageously applied, as a result of which small imperfections and / or micro-air inclusions are covered and the insulation property is improved.
Im Gegensatz zu üblichen EL-Folienaufbauten werden erfindungsgemäß vorzugsweise transparente polymere Dielektrikumsschichten 41 , 42, 43, 81 , 82, 83 verwendet, wobei auf eine möglichst geringe Schichtdicke geachtet werden muß, da üblicherweise keine die relative Dielektrizitätskonstante erhöhende Beimengungen hinzugefügt werden können, da derartige, beispielsweise aus feinen Bariumtitanat-Pigmenten bestehende, Beimengungen die Transparenz sehr stark beeinflussen würden und üblicherweise eine unerwünscht Opazität mit starker Reflektion bewirken würden.In contrast to conventional EL film constructions, transparent polymeric dielectric layers 41, 42, 43, 81, 82, 83 are preferably used according to the invention, whereby the smallest possible layer thickness must be taken into account, since usually no additions which increase the relative dielectric constant can be added, since such , for example consisting of fine barium titanate pigments, admixtures would have a very strong influence on the transparency and would usually bring about an undesired opacity with strong reflection.
Vorzugsweise wird die (weitgehend) transparente Rückelektrode 31 , 32, 33 mittels Siebdruck in Form einer intrinsisch leitfähiger Polymerschicht und/oder einer Schicht mit Metalloxiden, beispielsweise Indium-Zinn-Oxiden (ITO) oder Antimon- Zinn-Oxiden (ATO) hergestellt. Durch Applikation mittels Siebdruck kann die Rück- elektrode 31 , 32, 33 in grafischer und funktioneller Hinsicht weitgehend frei gestaltet werden. Da übliche elektrisch leitfähige Siebdruckpasten keine gute Flächenleitfähigkeit aufweisen, werden speziell bei größeren Flächen mittels gut elektrisch leitfähiger Pasten sogenannte Bus-bars (nicht dargestellt) berandend beziehungsweise umrandend gedruckt. Diese Bus-bars können femer für die Herausführung der elektrischen Anschlüsse verwendet werden.The (largely) transparent back electrode 31, 32, 33 is preferably produced by means of screen printing in the form of an intrinsically conductive polymer layer and / or a layer with metal oxides, for example indium tin oxides (ITO) or antimony tin oxides (ATO). By application by means of screen printing, the back electrode 31, 32, 33 can be designed largely freely in graphic and functional terms. Since conventional electrically conductive screen printing pastes do not have good surface conductivity, so-called bus bars (not shown) are printed bordering or bordering, especially in the case of larger areas, by means of well electrically conductive pastes. These bus bars can also be used for the execution of the electrical connections are used.
Grundsätzlich kann jedoch die Rückelektrode 31 , 32, 33 auch vollflächig mittels Rakeln, Rollenbeschichtung, Vorhanggießen, Sprühen und dergleichen Verfahren hergestellt werden.In principle, however, the back electrode 31, 32, 33 can also be produced over the entire surface by means of doctor blades, roller coating, curtain casting, spraying and the like.
Als letzter Einzelschritt in der Herstellung der einzelnen Elektrolumineszenzfolien 1 , 2, 3 können sogenannte Haftvermittlerschichten 72, 73 aufgebracht werden, die den Verbund der einzelnen Elektrolumineszenzfolien 1 , 2, 3 bewirken und/oder verbessern. Unter einer Haftvermittlerschicht 71 , 72, 73 wird in erster Linie eine transparente polymere Verbindungsschicht verstanden. Diese kann im Kaltklebeverfahren nach Abziehen einer Schutzfolie und der Applikation mittels Druck eine Verbindung bewirken. Es können jedoch auch Heißklebebeschichtungen verwendet werden, die unter Temperatur und Druck einen Haftverbund bewirken. Da ein optisch möglichst transparenter Verbund gefordert wird, muß die Haftvermittlerschicht 71 , 72, 73 transparent sein und der Verbund lufteinschlußfrei gestaltet werden. Ferner sollen durch die Haftvermittlerschicht 72, 73 auch Unebenheiten der vorangegangen Schichten ausgeglichen werden.As the last individual step in the production of the individual electroluminescent films 1, 2, 3, so-called adhesion promoter layers 72, 73 can be applied which bring about and / or improve the bond between the individual electroluminescent films 1, 2, 3. An adhesion promoter layer 71, 72, 73 is primarily understood to mean a transparent polymeric connecting layer. This can create a connection in the cold adhesive process after peeling off a protective film and application by means of pressure. However, hot-melt adhesive coatings can also be used, which bring about an adhesive bond under temperature and pressure. Since a composite that is as optically transparent as possible is required, the adhesive layer 71, 72, 73 must be transparent and the composite must be designed free of air inclusions. Furthermore, the adhesion promoter layer 72, 73 is also intended to compensate for unevenness in the preceding layers.
Generell kann die Verbindung der Elektrolumineszenzfolien 1 , 2, 3 mittels Kaltlamination und/oder Heißlamination flächig oder elementweise erfolgen. Wahlweise kann die Verbindung auch nur punktuell oder streifenförmig erfolgen, da gegebenenfalls beim Einbau in einer entsprechenden ' Applikation die drei Elektrolumineszenzfolien 1 , 2, 3 ohnedies zusammenfixiert werden.In general, the connection of the electroluminescent films 1, 2, 3 by means of cold lamination and / or hot lamination can take place flat or element-wise. Optionally, the connection can also be made only at points or in strips, since if necessary the three electroluminescent films 1, 2, 3 are fixed together when installed in a corresponding application.
Ist beidseitige Lichtemission erwünscht, müssen die Dielektrikumschichten 41 , 81 und die Rückelektrode 31 der untersten Elektrolumineszenzfolie weitgehend transparent ausgeführt werden, während für einseitige Lichtemission nach oben eine oder mehrere der genannten Lagen bevorzugt opak beziehungsweise reflektierend ausgebildet werden, und die Rückelektrode 31 zusätzlich diverse Verdrahtungsfunktionen übernehmen kann.If light emission on both sides is desired, the dielectric layers 41, 81 and the back electrode 31 of the lowermost electroluminescent film must be made largely transparent, while one or more of the layers mentioned are preferably designed to be opaque or reflective for one-sided light emission upwards, and the back electrode 31 additionally takes on various wiring functions can.
Erfindungsgemäß wurde die Anordnung Blau-Rot-Grün, wobei Grün an der Lichtaustrittsseite angeordnet ist, als sehr effizient für die Generierung einer möglichst großen Farbvielfalt und insbesondere zur Erzeugung der Farbe Weiß ermittelt. Es können je nach Verwendung der EL-Pigmente 4 beziehungsweise der Kombinationen von EL-Pigmenten 4 und der Verwendung entsprechender farbkonvertierender und/oder farbfilternder Substanzen auch andere Anordnungen beziehungsweise eine andere Reihenfolge zur Anwendung gelangen. -According to the invention, the arrangement blue-red-green, with green being arranged on the light exit side, was very efficient for generating one as large a variety of colors as possible, and in particular to produce the color white. Depending on the use of the EL pigments 4 or the combinations of EL pigments 4 and the use of corresponding color-converting and / or color-filtering substances, other arrangements or a different sequence can also be used. -
Wie oben bereits erwähnt, kann grundsätzlich anstelle der Verwendung eines weitgehend formstabilen Foliensubstrates 51 , 52, 53 die Leuchtschicht 1 1 , 1 2, 1 3 aus einer EL-Gießfolie gebildet werden. Unter EL-Gießfolien werden aus der Lösung mittels Gießverfahren hergestellte Dünnfolien verstanden, in welche die elektrolumineszierenden Pigmente mit einem Durchmesser kleiner 30 μm, bevorzugt kleiner 20 μm, besonders bevorzugt kleiner 1 5 μm, eingelagert sind. Derartige EL- Gießfolien sind relativ formstabil und können bevorzugt im Rolle-zu-Rolle Verfahren mit Elektrodenschichten 21 , 22, 23 mittels Vakuumtechnik oder Siebdruck oder Rakeln oder Rollenbeschichtung oder Sprühen oder Vorhanggießen beschichtet werden. Bei entsprechender Ausgestaltung der Leuchtschichten 1 1 , 1 2, 1 3 kann auf die Anbringung der Dielektrikaschichten 41 , 42, 43, 81 , 82, 83 verzichtet werden und damit eine sehr gute Transparenz und elektrische Durchschlagsfestigkeit und hervorragende Oberflächenplanizität erreicht werden. Der Nachteil dieser Methode liegt in der vollflächigen Ausführung der Leuchtschichten 1 1 , 1 2, 1 3 und damit der höheren Kosten durch einen erhöhten Anteil an EL-Pigmenten 4.As already mentioned above, instead of using a largely dimensionally stable film substrate 51, 52, 53, the luminescent layer 1 1, 1 2, 1 3 can be formed from an EL cast film. EL cast films are understood to mean thin films produced from the solution by means of casting processes, in which the electroluminescent pigments with a diameter of less than 30 μm, preferably less than 20 μm, particularly preferably less than 15 μm, are embedded. Such EL cast films are relatively dimensionally stable and can preferably be coated in a roll-to-roll process with electrode layers 21, 22, 23 by means of vacuum technology or screen printing or knife coating or roll coating or spraying or curtain casting. With a corresponding design of the luminescent layers 1 1, 1 2, 1 3, the application of the dielectric layers 41, 42, 43, 81, 82, 83 can be dispensed with and thus very good transparency and electrical dielectric strength and excellent surface planicity can be achieved. The disadvantage of this method lies in the full-surface design of the luminescent layers 1 1, 1 2, 1 3 and thus the higher costs due to an increased proportion of EL pigments 4.
Fig. 3 zeigt eine alternative Ausführungsform, wobei die Bezugszeichen entsprechender Schichten gegenüber Fig. 2 beibehalten wurden. Wie in Fig. 3 dargestellt und oben bereits erwähnt, kann anstelle der Verwendung eines weitgehend formstabilen Foliensubstrates 53 die mittlere Elektrolumineszenzfolie 3 unter Verwendung einer EL-Gießfolie als Leuchtschicht 13 gebildet werden. Auch die anderen Elektrolumineszenzfolien 1 , 2 können bei entsprechender Herstellung der Leuchtschichten 1 1 , 1 2 grundsätzlich ohne Foliensubstrat 51 , 52 gestaltet sein.FIG. 3 shows an alternative embodiment, the reference numbers of corresponding layers being retained compared to FIG. 2. As shown in FIG. 3 and already mentioned above, instead of using a largely dimensionally stable film substrate 53, the middle electroluminescent film 3 can be formed using an EL cast film as the luminescent layer 13. The other electroluminescent films 1, 2 can in principle be designed without the film substrate 51, 52 if the luminescent layers 11, 12 are produced accordingly.
Ein Vorteil der in Fig. 3 dargestellten Anordnung liegt in der Einsparung von ein oder zwei Elektrodenschichten. In dieser Darstellung wird ein spiegelbildlicher Aufbau der oberen und unteren Elektrolumineszenzfolien 1 , 2 gezeigt, und die mittlere Elektrolumineszenzfolie 3 ist mit gegossener Leuchtschicht 1 3 und zwei Dielektrikaschichten 43, 83 ausgeführt. Diese beiden Dielektrikaschichten 43, 83 können alternativ auch auf beiden Seiten der Leuchtschicht 1 3 angeordnet sein und können ferner für die Haftvermittlung verwendet werden und farbkonvertierende und/ oder farbfiltemde Beimengungen enthalten. Die Haftvermittlerschichten 71 , 72 der oberen und unteren Elektrolumineszenzfolien 1 , 2 können entfallen, und die Rückelektroden 31 , 32 der oberen und unteren Elektrolumineszenzfolien 1 , 2 bilden die Elektroden für den mittlere EL-Kondensator.An advantage of the arrangement shown in FIG. 3 is the saving of one or two electrode layers. In this illustration, a mirror-image structure of the upper and lower electroluminescent films 1, 2 is shown, and the middle electroluminescent film 3 is with cast luminescent layer 1 3 and two Dielectric layers 43, 83 executed. These two dielectric layers 43, 83 can alternatively also be arranged on both sides of the luminescent layer 1 3 and can furthermore be used for promoting adhesion and contain color-converting and / or color-filtering admixtures. The adhesive layers 71, 72 of the upper and lower electroluminescent films 1, 2 can be omitted, and the back electrodes 31, 32 of the upper and lower electroluminescent films 1, 2 form the electrodes for the middle EL capacitor.
Als besonders günstiger Kompromiß aus sicherer Funktion und guter Herstellbarkeit hat sich der in Fig. 4 dargestellte Aufbau einer Elektrolumineszenzfolie 1 erwiesen. Drei (ggf. auch zwei) gleichartige, sich nur durch ihre Leuchtfarbe unterscheidende Elektrolumineszenzfolien der dargestellten Art werden dabei miteinander zu einem erfindungsgemäßen Mehrfarb-Elektroluminseszenzelement kombiniert. DieThe construction of an electroluminescent film 1 shown in FIG. 4 has proven to be a particularly favorable compromise of reliable function and good manufacturability. Three (possibly also two) similar electroluminescent films of the type shown, which differ only in their luminous color, are combined with one another to form a multicolor electroluminescent element according to the invention. The
Elektrolumineszenzfolie 1 besteht im wesentlichen aus einem Foliensubstrat 51 aus PET oder anderem Kunststoff, auf welches die Elektrodenschicht 21 aufgedampft oder aufgesputtert ist, einer Leuchtschicht 1 1 und einer durch Siebdruck darauf aufgebrachten transparenten Rückelektrode 31 , Welche mittels der isolierenden Folie 91 einlaminiert ist. Grundsätzlich sind auch Substrate denkbar, welche nicht aus einer Kunststoffolie, sondern aus einem keramischen Material, beispielsweise Glas, bestehen. Electroluminescent film 1 essentially consists of a film substrate 51 made of PET or other plastic, onto which the electrode layer 21 is vapor-deposited or sputtered, a luminescent layer 11 and a transparent back electrode 31 applied by screen printing, which is laminated by means of the insulating film 91. Basically, substrates are also conceivable which do not consist of a plastic film but of a ceramic material, for example glass.

Claims

PATENTANSPRÜCHE
1 . Mehrfarb-Elektrolumineszenz-Element, aufweisend - eine erste Elektrolumineszenzfolie (1 ), welche eine erste Elektrodenschicht (21 ), eine erste Leuchtschicht (1 1 ) mit dispersen Elektroluminophoren (4) und eine Rückelektrodenschicht (31 ) aufweist, und - eine zweite Elektrolumineszenzfolie (2), welche eine zweite Elektrodenschicht (22) und eine zweite Leuchtschicht (1 2) mit dispersen Elektroluminophoren (4) aufweist, wobei die zweite Elektrolumineszenzfolie (2) zum Emittieren von Licht einer anderen Farbe als die erste Elektrolumineszenzfolie (1 ) ausgebildet ist.1 . Multi-color electroluminescent element, comprising - a first electroluminescent film (1) which has a first electrode layer (21), a first luminescent layer (1 1) with disperse electroluminophores (4) and a back electrode layer (31), and - a second electroluminescent film ( 2), which has a second electrode layer (22) and a second luminescent layer (1 2) with disperse electroluminophores (4), the second electroluminescent film (2) being designed to emit light of a different color than the first electroluminescent film (1).
2. Mehrfarb-Elektrolumineszenz-Element gemäß Anspruch 1 , wobei die zweite Elektrolumineszenzfolie (2) ebenfalls eine Rückelektrodenschicht (32) aufweist.2. Multi-color electroluminescent element according to claim 1, wherein the second electroluminescent film (2) also has a back electrode layer (32).
3. Mehrfarb-Elektrolumineszenz-Element gemäß einem der vorangehenden Ansprüche, ferner aufweisend eine dritte Elektrolumineszenzfolie (3), welche eine dritte Leuchtschicht (1 3) mit dispersen Elektroluminophoren (4) aufweist.3. Multi-color electroluminescent element according to one of the preceding claims, further comprising a third electroluminescent film (3) which has a third luminous layer (1 3) with disperse electroluminophores (4).
4. Mehrfarb-Elektrolumineszenz-Element gemäß Anspruch 3, wobei die dritte Elektrolumineszenzfolie (3) ebenfalls eine Elektrodenschicht (23) aufweist.4. Multi-color electroluminescent element according to claim 3, wherein the third electroluminescent film (3) also has an electrode layer (23).
5. Mehrfarb-Elektrolumineszenz-Element gemäß Anspruch 4, wobei die dritte Elektrolumineszenzfolie ferner ebenfalls eine Rückelektrodenschicht (33) aufweist. 5. Multi-color electroluminescent element according to claim 4, wherein the third electroluminescent film further also has a back electrode layer (33).
6. Mehrfarb-Elektrolumineszenz-Element gemäß einem der vorangehenden Ansprüche, wobei zumindest eine Elektrolumineszenzfolie (1 , 2, 3) ein Foliensubstrat (51 , 52, 53) aufweist, welches mit einer der Elektrodenschichten (21 , 22, 23) versehen ist.6. Multi-color electroluminescent element according to one of the preceding claims, wherein at least one electroluminescent film (1, 2, 3) has a film substrate (51, 52, 53) which is provided with one of the electrode layers (21, 22, 23).
7. Mehrfarb-Elektrolumineszenz-Element gemäß Anspruch 6, wobei zumindest zwei der Elektrolumineszenzfolien (1 , 2, 3) jeweils ein Foliensubstrat (51 , 52, 53) aufweisen, welches mit jeweils einer der Elektrodenschichten (21 , 22, 23) versehen ist.7. Multi-color electroluminescent element according to claim 6, wherein at least two of the electroluminescent films (1, 2, 3) each have a film substrate (51, 52, 53) which is provided with one of the electrode layers (21, 22, 23) ,
8. Mehrfarb-Elektrolumineszenz-Element gemäß Anspruch 7 mit drei Elektrolumineszenzfolien (1 , 2, 3), wobei alle drei Elektrolumineszenzfolien (1 , 2, 3) jeweils ein Foliensubstrat (51 , 52, 53) aufweisen, welches mit jeweils einer der Elektrodenschichten (21 , 22, 23) versehen ist.8. Multi-color electroluminescent element according to claim 7 with three electroluminescent films (1, 2, 3), wherein all three electroluminescent films (1, 2, 3) each have a film substrate (51, 52, 53), each with one of the electrode layers (21, 22, 23) is provided.
9. Mehrfarb-Elektrolumineszenz-Element gemäß einem der Ansprüche 6-8, wobei zumindest ein Foliensubstrat (51 , 52, 53) aus Polyethylenterephthalat besteht.9. Multi-color electroluminescent element according to one of claims 6-8, wherein at least one film substrate (51, 52, 53) consists of polyethylene terephthalate.
1 0. Mehrfarb-Elektrolumineszenz-Element gemäß einem der Ansprüche 6-9, wobei zumindest eine der Elektrodenschichten (21 , 22, 23) auf das zugehörige Foliensubstrat (51 , 52, 53) vakuumtechnisch aufgedampft oder gesputtert ist.1 0. Multi-color electroluminescent element according to one of claims 6-9, wherein at least one of the electrode layers (21, 22, 23) on the associated film substrate (51, 52, 53) is vapor-deposited or sputtered.
1 1 . Mehrfarb-Elektrolumineszenz-Element gemäß einem der vorangehenden Ansprüche, wobei mindestens eine der Leuchtschichten (1 1 , 1 2, 1 3) als gegossene Folie ausgeführt ist.1 1. Multi-color electroluminescent element according to one of the preceding claims, wherein at least one of the luminescent layers (1 1, 1 2, 1 3) is designed as a cast film.
1 2. Mehrfarb-Elektrolumineszenz-Element gemäß einem der vorangehenden Ansprüche, wobei die dispersen Elektroluminophore (4) anorganischer Natur sind.1 2. Multi-color electroluminescent element according to one of the preceding claims, wherein the disperse electroluminophores (4) are inorganic in nature.
1 3. Mehrfarb-Elektrolumineszenz-Element gemäß Anspruch 1 2, wobei die dispersen Elektroluminophore (4) mikroverkapselt sind.1 3. Multi-color electroluminescent element according to claim 1 2, wherein the disperse electroluminophores (4) are microencapsulated.
14. Mehrfarb-Elektrolumineszenz-Element gemäß einem der vorangehenden Ansprüche, das mindestens eine zusätzliche Dielektrikumsschicht (41 , 42, 43) enthält. 14. Multi-color electroluminescent element according to one of the preceding claims, which contains at least one additional dielectric layer (41, 42, 43).
1 5. Mehrfarb-Elektrolumineszenz-Element gemäß einem der vorangehenden Ansprüche, wobei die Elektrolumineszenzfolien (1 , 2, 3) durch mindestens eine Haftschicht (71 , 72, 73) miteinander verbunden sind.1 5. Multi-color electroluminescent element according to one of the preceding claims, wherein the electroluminescent films (1, 2, 3) are interconnected by at least one adhesive layer (71, 72, 73).
1 6. Mehrfarb-Elektrolumineszenz-Element gemäß einem der vorangehenden Ansprüche, wobei mindestens eine Schicht des Mehrfarb-Elektrolumineszenz- Elements mindestens eine farbkonvertierende und/oder farbfiltemde organische und/oder anorganische Beimengung enthält.6. A multicolor electroluminescent element according to one of the preceding claims, wherein at least one layer of the multicolor electroluminescent element contains at least one color-converting and / or color-filtering organic and / or inorganic admixture.
1 7. Mehrfarb-Elektrolumineszenz-Element gemäß einem der vorangehenden Ansprüche, wobei jede Rückelektrodenschicht (31 , 32, 33) weitgehend transparent ausgeführt ist.1 7. Multi-color electroluminescent element according to one of the preceding claims, wherein each back electrode layer (31, 32, 33) is largely transparent.
1 8. Mehrfarb-Elektrolumineszenz-Element gemäß einem der Ansprüche 1 -1 6, wobei die erste Elektrodenschicht (21 ) oder die Rückelektrodenschicht (31 ) der ersten Elektrolumineszenzfolie (1 ) intransparent reflektierend ausgeführt ist.1 8. Multi-color electroluminescent element according to one of claims 1 -1 6, wherein the first electrode layer (21) or the back electrode layer (31) of the first electroluminescent film (1) is made non-transparent reflective.
1 9. Mehrfarb-Elektrolumineszenz-Element gemäß einem der vorangehenden Ansprüche, wobei zumindest eine der Elektrodenschichten (21 , 22, 23) und/oder Rückelektrodenschichten (31 , 32, 33) zumindest teilweise mittels Laserstrahl strukturiert oder konturiert ist.1 9. Multi-color electroluminescent element according to one of the preceding claims, wherein at least one of the electrode layers (21, 22, 23) and / or back electrode layers (31, 32, 33) is at least partially structured or contoured by means of a laser beam.
20. Mehrfarb-Elektrolumineszenz-Element gemäß einem der vorangehenden Ansprüche, wobei jede Elektrolumineszenzfolie (1 , 2, 3) separat elektrisch ansteuerbar ist.20. Multi-color electroluminescent element according to one of the preceding claims, wherein each electroluminescent film (1, 2, 3) is separately electrically controllable.
21 . Mehrfarb-Elektrolumineszenz-Element gemäß Anspruch 1 9 mit 3 Elektrolumineszenzfolien (1 , 2, 3), wobei eine der Elektrolumineszenzfolien (1 , 2, 3) zum Emittieren roten Lichts, eine der Elektrolumineszenzfolien (1 , 2, 3) zum Emittieren grünen Lichts, und eine der Elektrolumineszenzfolien (1 , 2, 3) zum Emittieren blauen Lichts ausgebildet ist.21st Multi-color electroluminescent element according to claim 1 9 with 3 electroluminescent films (1, 2, 3), one of the electroluminescent films (1, 2, 3) for emitting red light, one of the electroluminescent films (1, 2, 3) for emitting green light , and one of the electroluminescent films (1, 2, 3) is designed to emit blue light.
22. Mehrfarb-Elektrolumineszenz-Element gemäß einem der vorangehenden Ansprüche, wobei mindestens eine der Elektrolumineszenzfolien (1 , 2, 3) in unabhängig voneinander elektrisch ansteuerbare Segmente unterteilt ist.22. Multi-color electroluminescent element according to one of the preceding claims, wherein at least one of the electroluminescent films (1, 2, 3) in independently controllable segments is divided.
23. Verfahren zur Herstellung eines Mehrfarb-Elektrolumineszenz-Elements, wobei mindestens zwei Elektrolumineszenzfolien (1 , 2, 3) zusammengefügt werden.23. A method for producing a multicolor electroluminescent element, wherein at least two electroluminescent films (1, 2, 3) are joined together.
24. Verfahren zur Herstellung eines Mehrfarb-Elektrolumineszenz-Elements gemäß Anspruch 23, wobei drei Elektrolumineszenzfolien (1 , 2, 3) zusammengefügt werden.24. The method for producing a multicolor electroluminescent element according to claim 23, wherein three electroluminescent films (1, 2, 3) are joined together.
25. Verfahren gemäß einem der Ansprüche 23-24, wobei das Zusammenfügen mittels Kaltlaminieren und/oder Heißlaminieren und/oder Vakuumlaminieren erfolgt.25. The method according to any one of claims 23-24, wherein the joining takes place by means of cold lamination and / or hot lamination and / or vacuum lamination.
26. Verfahren gemäß einem der Ansprüche 23-25, wobei nach dem Zusammenfügen mindestens eine Schicht des Mehrfarb-Elektrolumineszenz-Elements mit einem Laserstrahl bearbeitet wird. 26. The method according to any one of claims 23-25, wherein after joining together at least one layer of the multicolor electroluminescent element is processed with a laser beam.
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