Method and arrangement for the production of a thin layered structure

[0001] The invention relates to a method of producing a thin laminated construction according to the precharacterizing clause of claim 1, as well as to an apparatus for implementing this method.

[0002] Structures consisting of thin layers supported on large-area, thin carriers are becoming increasingly important in various areas of technology. Known and economically highly significant examples include thin-layer transistor structures, such as are employed in particular in liquid-crystal display arrangements, and other thin-layer systems for display units such as plasma displays. Additional thin-layer devices that are both technically and economically significant are the separator structures of electrochemical elements, in particular primary or secondary elements based on lithium (lithium batteries and lithium-ion accumulators, etc.) as well as highly differentiated membrane systems for separating substances and obtaining energy, for instance fuel cells.

[0003] To produce such thin-layer systems, it is ordinarily necessary for a thin coating in an initial state, following application to a thin carrier, to be converted to a functional layer and firmly bonded to the carrier. The aim here is that the process should be carried out with high reliability, excluding all possibility of damage to the carrier or the coating material, and with high productivity, i.e. a high throughput in terms of unit area per unit time.

[0004] For the various thin-layer systems of this generic kind that are currently of great technological importance, various kinds of manufacturing procedures are known, but they do not entirely satisfy these demands.

[0005] The objective of the invention is thus to disclose an improved method of this generic kind that is nearly universally applicable, can easily be adapted to diverse specific layer structures, and is characterized by potentially high productivity, simplicity and reliability while largely excluding damage to the coating(s) and/or to the carrier.

[0006] This objective is achieved by a method with the characteristics given in claim 1. A useful apparatus to implement this method is disclosed in claim 17.

[0007] The invention incorporates the fundamental idea that the original coating material applied in each case is converted into the functional layer of the laminated construction, and simultaneously bonded to the carrier, by applying electromagnetic radiation in the near-infrared (NIR) region, i.e. the wavelength region between 0.8 and 1.5 m, to the continuously transported product. The effect thereby achievedto different degrees, depending on the specific layer systemis in particular a drying and/or cross-linkage of the original coating material, in many cases combined with melting and hence fusion to the carrier.

[0008] The radiation employed in accordance with the invention can be produced in a simple and economical way by operating a high-power halogen lamp at an elevated temperature.

[0009] In preferred laminated constructions both the original coating material and the carrier have an intermediate thickness in the range between 5 m and 500 m, in particular between 20 m and 200 m.

[0010] Materials used as the carrier in important applications are in particular various plastic films, especially PE, PP or PVC films, or metal foils or fine woven fabrics made of metal, especially aluminum or copper or their alloys. The original coating material is in particular applied in liquid or pasty form, or else as a powder, by means of suitable coating techniques known per se, preferably being spun, rolled, sprayed, sprinkled or blown onto the carrier.

[0011] The spectral composition of the infrared radiation used for processing is adjusted in accordance with the absorption properties of the original coating material, preferably in such a way that the material is heated substantially uniformly over the thickness of the layer, so as to avoid imposing an unacceptable thermal stress on the carrier or on individual regions of the coating. This adjustment can be carried out by way of the operating voltage; furthermore, filters can be inserted. The adjustment of strength of the incident radiation can be accomplished in particular by varying the distance between the radiation source and the surface of the layered structure. The radiation can be sent directly into the coating or through the carrier or be applied from both sides.

[0012] By means of a stream of gas that passes over the surface of the applied original coating material and/or the back surface of the carrier (for which in many cases of application an airstream suffices), it is possible on one hand to make the temperature distribution more uniform and, where desired, to reduce the surface temperature, while on the other hand volatile components of the original coating material can rapidly be removed. As a result, the reliability and efficiency of the method can be further increased. The flowing gas (air) is preferably dry and cold and is applied with high pressure or impetus.

[0013] In a further refinement of the method a means of regulating performance based on feedback of detector signals (e.g., from temperature sensors) is provided.

[0014] The proposed method is suitable for manufacturing thin-layer transistor arrangements, in particular liquid-crystal display arrangements, and separator membranes for electrochemical elements, in particular lithium-ion accumulators, as well as for manufacturing thin-layer structures for plasma displays and membrane structures for fuel cells.

[0015] A preferred apparatus for implementing the method comprises the following: a delivery and forward-feed device suitable for handling a quasi-endless carrier, which in particular can consist of a supply roll of the carrier material and a forward-feed mechanism employing rollers; a delivery and layer producing device to deliver the original coating material and apply it to the carrier surface so as to form a layer; and the NIR irradiation device, which in particular consists of one or more halogen lamps with a large spectral component in the NIR plus an appropriate power supply.

[0016] In preferred embodiments of this apparatus there is additionally provided a flow-generating device to produce and direct the above-mentioned gas stream and/or a device for adjusting or regulating the strength of the incident radiation, the latter preferably comprising means for altering the distance between the radiation source and layered structure.

[0017] The implementation of the invention is not restricted to the particular applications and aspects described above but is also possible in a large number of further applications and with additional aspects, the discovery of which is within the competence of those skilled in the art.