Abstract: The present invention relates to a control system (10; 30; 50) for a LED luminary (12) including a plurality of LED light sources of multiple colors for producing a mixed color light. The control system comprises means (22) for controlling the LED light sources in accordance with a difference between set point values representing a desired light output and first control data provided by at least one optical sensor (14; 32) responsive to a property of the light produced by the LED light sources. The control system is characterized by means (26; 38) for compensating said set point values in accordance with second control data provided by a temperature sensor (24) responsive to the temperature of the optical sensor(s) (14; 32). The additional temperature sensor makes it possible to compensate for changes in the spectral sensitivity of the optical sensor(s), whereby the color stability of the LED luminary with integrated optical sensors can be increased.

Abstract: A lighting arrangement (100) provides light (117) of a desired color. The arrangement comprises a plurality of light sources (101, 102, 103) that each emit light of a respective color that, when mixed, is perceivable as the desired color. A light detector (197) is configured to receive light (116) reflected by a color reference surface (109) having a specific reference color. The detector also provides a s (105) analyzes the signal from the light detector and recognizes the color of the received light as the color of the reference surface. The controller controls the light sources such that the desired color corresponds to the color of the color reference surface.

Abstract: Low-pressure mercury vapor discharge lamp comprises a light-transmitting discharge vessel (10) enclosing, in a gastight manner, a discharge space (13) provided with a filling of mercury and a rare gas. The discharge vessel comprises discharge means (20a; 20b) for maintaining a discharge in the discharge space. The discharge vessel is provided with a container comprising an amalgam (2). The container is provided with releasing means (4) for the controlled release of mercury vapor from the amalgam. The releasing means is open during lamp operation and is substantially closed when, during lamp operation, the temperature of the amalgam becomes higher than a pre-determined temperature. Preferably, the pre-determined temperature corresponds to a temperature of a range of temperatures at which the mercury-vapor pressure above the amalgam is relatively stable.