Karsten Eichhorn

Indirect blue light does not suppress nocturnal salivary melatonin in humans in an automobile setting

Abstract:  In 2007, the International Agency for Research on Cancer (IARC) classified shift work that involves circadian disruption as being probably carcinogenic to humans (Group 2A). In this context, light exposure during the night plays a key role because it can suppress nocturnal melatonin levels when exposures exceed a certain threshold. Blue light around 464 nm is most effective in suppressing melatonin because of the spectral sensitivity of melanopsin, a recently discovered photopigment in retinal ganglion cells; the axons of these cells project to the suprachiasmatic nucleus, a circadian master clock in the brain. Due to advances in light technologies, normal tungsten light bulbs are being replaced by light‐emitting diodes which produce quasi‐monochromatic or white light. The objective of this study was to assess whether the light–melanopsin–melatonin axis might be affected in automobiles at night which employ the new generation diodes. To this end, we have tested in an experimental automobile setting whether indirect blue light (λmax = 465 nm) at an intensity of 0.22 or 1.25 lx can suppress salivary melatonin levels in 12 male volunteers (age range 17–27 years) who served as their own controls. Daytime levels were low (2.7 ± 0.5 pg/mL), and night‐time levels without light exposure were high (14.5 ± 1.1 pg/mL), as expected. Low‐intensity light exposures had no significant effect on melatonin levels (0.22 lx: 17.2 ± 2.8 pg/mL; P > 0.05; 1.25 lx: 12.6 ± 2.0 pg/mL; P > 0.05). It is concluded that indirect blue light exposures in automobiles up to 1.25 lx do not cause unintentional chronodisruption via melatonin suppression.

LEDs in automotive lighting

Light emitting diodes (LED) are becoming more and more significant in interior and exterior automotive lighting. The long service life, energy and space savings, shock and vibration resistance and new styling potential are the main advantages of using LEDs in automotive applications. Today, most central high mounted stop lamps use LEDs. In rear combination lamps the number of LEDs in amber and red is increasing rapidly. This year, a first rear combination lamp using LEDs for all functionalities including the back-up lamp function was realized. In addition, first signal functions in headlamps using white High Power LEDs were launched onto the market. The long service life characteristic makes LEDs especially predestined for the DRL function combined with the position/parking light. Exterior automotive applications, including requirements and performance will be discussed and an outlook will be given on future scenarios.

Aktives Licht: Innovative Ansätze für die nächste Scheinwerfer-Generation

Neue optische Technologien erlauben in der naechsten Scheinwerfer-Generation eine noch gezieltere Verteilung des Lichtes im Strassenraum. Gepaart mit der Intelligenz von Sensoren und Datenverarbeitung, die zunehmend ins Fahrzeug Einzug finden, werden Lichtfunktionen ueber Adaptive Frontlighting Systems (AFS) hinaus realisierbar. Im Fokus steht dabei die situationsangepasste Modulation der Lichtverteilung oberhalb der heutigen Hell-Dunkel-Grenze (HDG). Markierungslicht und blendfreies Fernlicht zeigen exemplarisch, wie das naechtliche Fahren in Zukunft sicherer und komfortabler gestaltet wird.

Blinkleuchtenintegration in Scheinwerefern

Die zunehmenden Bestrebungen der Automobilhersteller, den vorderen Fahrtrichtungsanzeiger in den Scheinwerfer einzubinden, haben viele Grunde. Nicht zuletzt sind Stylingvorgaben und Aerodynamik dafur verantwortlich, dass die Frontflachen moderner Kraftfahrzeuge immer kleiner werden. Somit werden Funktionen wie das Blinklicht zwangslaufig in den Scheinwerfer integriert. In Zukunft schaffen alternative Lichtquellen, gekoppelt mit anspruchsvollen optischen Systemen, die Voraussetzungen fur vollig neuartige Scheinwerferkonzepte und Erscheinungsbilder, die bisher nicht realisierbar waren.