UV light-emitting diodes as a radiation source in a device for the artificial weathering of samples

Abstract

The usual xenon radiation source in conventional weathering testers is replaced by UV light-emitting diodes (LEDs) ( 6 ). These can be used to provide a good approximation of the UV component of the solar spectrum, in particular when different types of UV light-emitting diodes ( 6 ) with different emission characteristics are employed. Optionally, further light-emitting diodes in the visible spectral range may also be used in order to cover other parts of the solar spectrum. The light-emitting diodes ( 6 ) may be mounted on a flexible printed circuit board ( 5 ), which may in turn be fitted on a tubular holding body ( 4 ). The flexible printed circuit board carrying the light-emitting diodes may also be placed on other substrates ( 7 ) which are pliable in a geometrically stable way, so that that they can be arranged at a uniform distance from material samples with a particular surface topology, in order to obtain uniform exposure.

Description

technical field [0001] The invention relates to a device for artificially weathering samples. In this device, the weather-dependent aging of test samples, in particular test samples of flat material, is evaluated by artificially weathering the test samples. For this purpose, such devices generally have a weathering chamber containing a support for the sample to be aged; and a radiation source for applying radiation, especially UV radiation, to the sample. Background technique [0002] This device for artificially weathered specimens is used to assess the lifetime of materials that are subjected to climatic influences such as sunlight, solar heat, humidity, etc. due to their constant exposure to natural weathering environments during use. In order to obtain a good simulation of natural weathering conditions, the spectral energy distribution of the light generated in the installation should be as close as possible to that in natural solar radiation, for which purpose xenon ra...

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Problems solved by technology

However, due to the relatively low magnitude of the spectral exposure on the specimen itself, relatively long exposure times are required

[0007] Another disadvantage of the aforementioned radiation sources commonly used in weathering detectors is that, due to the way they are designed and operated, they are relatively inflexible, e.g. the inability to adjust optimal conditions to the sample surface of the sample of material to be exposed

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