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Lighting devices (LD) operated in vibrating conditions result in nonuniform, in terms of time and space, energy density of the light flux generated. As a result, shadow distortions take place on the illuminated surface with varying frequency. For this reason safety of transport vehicles (TV) equipped with LD and operated in darkness hours and in vibrating condition is reduced. LD illuminating parameters are adjusted and controlled in accordance with the relevant documents in static conditions. In this case nonuniformity of LD light flux due to TV vibration is not taken into account. Nonuniformity of LD light flux is increased thanks to roughness of the deformed LD reflective or refracting surface. The purpose of this study is to develop the parameters indicative of nonuniformity of the light flux of LD to dynamic, nonstationary loading. The methodology of the study included two stages: Resonance frequencies were determined for a real-time 3D LD model; for frequencies, the value of which attributed to the frequency range of TV vibrations, deformations of the diffuser for one light source (incandescent lamp) and deformation of the baseplate carrying a set of light-emitting diodes (LEDs) were determined; by applying the laws of geometric optics light fluxes for the deformed diffuser and the deformed baseplate were determined; simulative nonuniformity of the light flux was researched on a screen located at the distance away from LD which is prescribed by the relevant specification documents. Both smooth and rough refracting surfaces of LED secondary optics were studied, as well as the deformed surfaces of LD reflecting diffusers. Digital images of the light flux nonuniformity was converted using mapping method into an information pattern, which constituted a shape with the area of 1 and with borders in the form of orthogonal interval of finite lengths. Isoperimetric parameters – a perimeter and mass center – were used for numerical parametrization of the intervals limited by the borders of the information pattern. The proposed method – using the example of analysis of the designs of a railway locomotive headlamp and an airplane landing light – proved high sensitivity to minimum changes in time and space of the light flux of LD operated in vibrating conditions. The proposed method allows to account for roughness of LD optical surfaces as a contributor to the light flux nonuniformity. Isoperimetric parameters were used for numerical parametrization of nonuniformity of the light flux. This method allows to optimize LD design and the technology for manufacturing its optical elements with the purpose of ensuring the requisite nonuniformity of the light flux generated.
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