Abstract: A device for emitting electromagnetic radiation, in particular UV radiation, including at least one radiating unit that only emits radiation at visible wavelengths. The device further includes a unit for detecting a functional error of the radiating unit. In practice, the radiating unit is provided for emitting only UV radiation and/or IR radiation and is formed by a light diode. The detection unit is designed to continuously monitor the radiating unit for functional errors, and the device includes an open-loop and/or closed-loop control unit which is provided to automatically switch off the radiating unit and/or display the functional error, upon detection of the functional error by the detection unit.

Abstract: A light, in particular for testing workpiece surfaces using a fluorescent marking device, which light has at least two lighting elements that emit electromagnetic radiation with different wavelength ranges. The intensity with which the lighting element irradiates can be adjusted separately for at least one of the lighting elements. Expediently, the light is configured to increase or reduce the intensity of at least one of the lighting elements and at the same time to keep the intensity of at least one other of the lighting elements constant, or to reduce it or increase it in the opposite way to the first-mentioned lighting element. The light is configured to adjust the intensity at such a speed that the human eye can adapt to a change in the intensity during the adjustment without adverse effects on the person's sight.

Abstract: A device for emitting electromagnetic radiation, in particular UV radiation, including at least one radiating unit that only emits radiation at visible wavelengths. The device further includes a unit for detecting a functional error of the radiating unit. In practice, the radiating unit is provided for emitting only UV radiation and/or IR radiation and is formed by a light diode. The detection unit is designed to continuously monitor the radiating unit for functional errors, and the device includes an open-loop and/or closed-loop control unit which is provided to automatically switch off the radiating unit and/or display the functional error, upon detection of the functional error by the detection unit.

Abstract: A light, in particular for testing workpiece surfaces using a fluorescent marking device, which light has at least two lighting elements that emit electromagnetic radiation with different wavelength ranges. The intensity with which the lighting element irradiates can be adjusted separately for at least one of the lighting elements. Expediently, the light is configured to increase or reduce the intensity of at least one of the lighting elements and at the same time to keep the intensity of at least one other of the lighting elements constant, or to reduce it or increase it in the opposite way to the first-mentioned lighting element. The light is configured to adjust the intensity at such a speed that the human eye can adapt to a change in the intensity during the adjustment without adverse effects on the person's sight.