Process and apparatus for coating with a liquid

Abstract

In order to save material and evenly coat the substrate, the present invention provides a liquid coating method. In this way, a reservoir (6) is formed by a transversely open channel (5) and a surface (91) of the base (9) facing the transverse opening (47) of this channel (5). Filled by the fluid coating material (35), a gap (7) is maintained between the guide groove (5) and the surface (91) of the substrate (9), the liquid level (36) of the fluid coating material (35) is at the substrate ( 9) the surface (91) forms a meniscus. During the coating process, the substrate (9) moves through the guide groove (5) along a direction (42) with a vertical component, or the guide groove (5) moves through the substrate along a direction (42) with a vertical component ( 9).

Description

technical field [0001] The present invention relates generally to the manufacture of coatings from liquid-applied coating materials, and more particularly to the manufacture of electro-optical components. Background technique [0002] When fabricating layers for organic light-emitting devices (OLEDs), special requirements are layer uniformity and layer thickness. To coat extremely thin functional layers on organic light-emitting devices, such layers are usually applied by evaporative coating, especially in display applications. However, the molecular weight of the organic substrate used in this case cannot be too high. [0003] In contrast, when liquid coating is used, it is possible to apply polymer film layers with higher stability. The advantage of liquid coating compared to vacuum coating is that large surfaces can be coated simply and inexpensively. Vacuum coating of flat panels of several square meters would require uneconomically large vacuum units. Liquid coating...

AI Technical Summary

Problems solved by technology

[0005] However, on the other hand, the problem with liquid coating is how to make thin and uniform film layers

This process also has the problem of how to achieve uniform film thickness when producing uniform large-area coatings

In addition, as a local application process, the inkjet printing process is slower than other liquid coating processes, requiring high process investment, through the work of many parallel printing heads to speed up the process, This leads to an increase in manufacturing costs

[0009] Disadvantages of other printing processes, such as screen printing in particular, are the contact with the surface of the product being coated, which when using sensitive substrates, such as coating onto organic light-emitting devices is typical, leads to increased reject rates

Furthermore, the applied film layer is contaminated by printing press wear

At the same time, the large surface of the printing press can lead to rapid drying of the coating solution and thus contamination of the applied film with dried material

[0010] Finally, casting processes, such as curtain coating, are not suitable for applying thin film layers due to the large amount of coating material applied per unit of time

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