Abstract: The invention relates to a method for monitoring the condition of a medium in a channel, based on the transmission/emission of light, in which a light at a set wavelength is conducted through a medium layer defined by a measuring gap in a measuring head pushed in from an opening in the wall of the channel the intensity of the light passed through medium layer, or a variable proportional to it is measured, and the condition of the medium is evaluated, using measuring electronics, from the change of the intensity, according to established criteria. In the method, the wavelength of light used is such that the resolution of the aging phenomenon of the medium being monitored is optimal and the relationship of the temperature dependence of the medium to the measuring variable is taken into account. In addition, the invention also relates to a corresponding device.

Abstract: The invention relates to a method for monitoring the condition of a medium, based on the transmission/emission of light in a channel, in which a light is conducted through a medium layer defined by a measuring gap in a measuring head pushed in from an opening in the wall of the channel, the intensity of the light, or a variable proportional to it is measured through the medium layer, and the condition of the medium is evaluated, using measuring electronics, from the intensity of the change, according to set criteria. The measurement is performed using a sensor with a compact measuring head, in which the measuring electronics are essentially outside the channel, and in which the light is conducted to the measuring gap and away from the measuring gap by optical-fibre means. In addition, the invention also relates to a corresponding device.

Abstract: Low power consumption display devices are disclosed. Phoactive layers are utilized that both respond to electrical energy to allow a display device to display information and that generate electrical energy in response to incident radiation. Display pixels of a single display device may be divided displaying and generating pixels. The displaying pixels may display information and the generating pixels may generate electrical energy. The generated electrical energy may be used to provide power to drive an image.