Patent Grant
7686664
This application is related to co-pending application CML03478T, U.S. patent application Ser. No. 11/275,373, entitled “CUSTOMIZED ELECTROLUMINESCENT DISPLAY”, filed even date herewith and assigned to Motorola, Inc.
This invention relates generally to luminescent displays. More particularly, this invention relates to methods of manufacturing electroluminescent display devices that allow them to be easily customized.
Electroluminescent panels, lamps, and displays are light-emitting displays for use in many applications. Electroluminescent (EL) panels are essentially a capacitor structure with an inorganic phosphor sandwiched between two electrodes. The resistance between the two electrodes is almost infinite and thus direct current (DC) will not pass through it. But when an alternating voltage is applied, the build-up of a charge on the two surfaces effectively produces an increasing field (called an electric field) and this causes the phosphor to emit light. The increase in voltage in one direction increases the field and this causes a current to flow. The voltage then decreases and rises in the opposite direction. This also causes a current to flow. The net result is that current flows into the electroluminescent panel and thus energy is delivered to the panel. This energy is converted to visible light by the inorganic phosphor, with little or no heat produced in the process. Application of an alternating current (AC) voltage across the electrodes generates a changing electric field within the phosphor particles, causing them to emit visible light. By making one or both of the electrodes so thin that light is able to pass through and be emitted to the environment, an optically transmissive path is available.
One particular area in which electroluminescent panels can be useful is in lighted advertising displays at the point of product purchase. In today's competitive global environment, local customization of the advertising display is often desirable to accommodate language nuances, local regulations, and cultural mores. However, prior art displays must be fabricated at a dedicated facility, and variations or changes in the display require costly tooling changes and lengthy lead times. This makes local customization very costly and/or impractical. Additionally, small volumes of a single display are also costly, due to the fixed cost of tooling.
The accompanying figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate various embodiments and to explain various principles and advantages all in accordance with the present invention. The drawings are intentionally not drawn to scale in order to better illustrate the invention.
As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting; but rather, to provide an understandable description of the invention. The terms a or an, as used herein, are defined as one or more than one. The term plurality, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more. The terms including and/or having, as used herein, are defined as comprising (i.e., open language).
An electroluminescent display device is fabricated by bonding a generic electroluminescent base laminate containing an electrode and an electroluminescent layer, to a custom graphic arts film containing a graphic element and a corresponding electrode. The generic electroluminescent base laminate is made at a first location or time, and the custom graphic arts film is made at a second location or time. Referring now to
A graphic arts laminate or graphic arts film 200 contains a second electrode 220 and a graphic element 260 disposed on a second substrate 210. The graphic arts laminate is fabricated at a place or time that is different from that which the generic EL base laminate 100 was produced. The graphic arts laminate 200 is then bonded to the generic EL base laminate 100 to form the customized EL display. The bonding can be achieved by, for example, a clear adhesive 270, or by heat and pressure. Typically, the graphic arts laminate 200 is made “locally” using, for example, commonly available printing techniques e.g. screen, flexo, gravure, litho, etc. Referring now to
In one embodiment, the second electrode 220 is disposed on one side of the second substrate 210 and a graphic element 260 that corresponds to the second electrode is disposed on an opposite side of the second substrate. Subsequently, the graphic arts laminate 200 is bonded to the generic base EL laminate 100 such that the second electrode faces the EL layer 140 on the generic base laminate. Referring now to
In another configuration, the graphic element 260 does not overlie the second electrode, such that the light emitted by the active portion of the EL layer 140 is not altered by a graphic element.
In still another configuration, the graphic element 260 is disposed directly over the second electrode 220, and both are on the same side of the second substrate 210.
In summary, without intending to limit the scope of the invention, the generic EL base layer has only one electrode and can be manufactured in bulk at low cost with low resolution screen printing techniques. The conductive layer that serves as the second electrode is printed on back surface of the graphic arts substrate using high resolution graphic arts printing well known in the graphic arts field e.g. flexo, gravure, litho, etc. This conductive electrode is patterned to correspond to the lighted area in the graphic arts image. Since the second conductive layer is printed on high resolution presses, the registration is superior to prior art method of creating EL displays. In one embodiment, conductive adhesive can be printed on top of the conductive layer. Non-conductive adhesive covers rest of the back surface on the graphic arts layer.
This novel method of fabricating a custom EL display facilitates significantly lower costs, especially at small volumes, and permits local customization of EL displays. The graphic arts elements can be changed and printed in each local market. This provides a competitive advantage in the highly brand specific, high turnover consumer space.
Having described several embodiments of our invention, it should be obvious that other arrangements of the various layers can be envisioned, yet still fall within the scope and intent of our invention. While the invention has been described in conjunction with specific embodiments, it is evident that many alternatives, modifications, permutations and variations will become apparent to those of ordinary skill in the art in light of the foregoing description. Accordingly, it is intended that the present invention embrace all such alternatives, modifications and variations as fall within the scope of the appended claims.
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| 20040195576 | Watanabe et al. | Oct 2004 | A1 |
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| Number | Date | Country | |
|---|---|---|---|
| 20070164658 A1 | Jul 2007 | US |
