Vluminanssikäyrä

Vluminanssikäyrä is a term used in some Finnish-language technical and educational contexts to describe a curve that represents the relation between luminance and a controlling parameter in luminescent systems. The concept is used to analyze how light output from a phosphorescent, fluorescent, or emissive display material responds to changes in stimulus such as irradiance, electric current, or time after excitation. In practice, the curve is plotted with luminance on the vertical axis and the stimulus parameter on the horizontal axis, and it may be adapted to include additional dimensions like wavelength or color coordinates.

Mathematically, vluminanssikäyrä is not tied to a single universal model. Depending on the mechanism, it can resemble an exponential rise or decay, a saturating hyperbola, or a logistic/S-shaped function. Common fitting approaches include L(t) = L0 e^{-t/τ} for decay processes or L(I) = Lmax I/(I + K) for saturation effects. In experimental work, researchers often compare curves by extracting parameters such as peak luminance, rise time, decay constant, and dynamic range to characterize material performance or display response.

Applications of the concept appear in materials science, display engineering, lighting research, and photography calibration. Measurements commonly rely on calibrated photometers or integrating spheres to obtain accurate luminance values, enabling comparisons across materials, devices, and operating conditions. The term vluminanssikäyrä reflects a practical descriptive tool rather than a fixed standard, and its exact definition can vary with the context of study.

Related topics include luminance, luminescence, decay curves, and brightness-response functions.