Ljuskilden

Ljuskilden, or ljuskilden in Swedish and Norwegian, is the term used for any device or natural phenomenon that emits visible light or other forms of electromagnetic radiation. In physics and everyday use, it covers both natural sources such as the sun, fire, and bioluminescent organisms, and artificial sources such as lamps, LEDs, and lasers.

Artificial light sources can be classified by how they produce light. Incandescent sources rely on a filament heated to incandescence, gas discharge sources use excited gases to emit light, and semiconductor-based sources such as LEDs and OLEDs convert electrical energy directly into light. Lasers produce highly coherent light with a narrow spectral range and are used in communications, medicine, and manufacturing.

Key properties used to describe a ljuskilde include luminous intensity (candela), luminous flux (lumen), illuminance (lux), and color temperature (kelvin). The color rendering index (CRI) indicates how faithfully colors appear under a given light. Efficiency and energy use are important considerations, with modern LEDs offering high luminous efficacy and long lifetimes compared with traditional incandescent lamps.

Applications and design consider factors such as glare, color quality, dimming, and control systems. Lighting design often integrates smart controls, energy considerations, and safety standards. Environmental and regulatory aspects cover electrical safety, photobiological safety, and energy labeling.

In practice, ljuskilden encompasses any emitter of light, from the natural glow of the sun to the most advanced artificial lighting technologies, forming a central concept in photometry, lighting engineering, and everyday illumination.