Posts Tagged ‘LED. flicker. modulation’

PRAD | Reportage | Flimmerndes Backlight – nur ein Mythos?.

Hier werden die Lichtmodulationen erklärt, die bei modernen Displays auftreten können.

„We’ve collected studies with hundreds of pages of research material that show no evidence other than speculative statistics to support claims that luminous modulation over 100Hz is visible or harmful to human health.

viaLEDs Magazine – Once Innovations intends to challenge DOE Energy Star requirements for integral LED lamps.

Note: The visibility of flicker and light modulation depends on a number of parameters. While it will not be easy to PROVE the harmful effects of flicker frequencies lower than 1000 Hz, it is easy to check if modulation frequencies above 100 Hz can be seen. As soon as you move the light source and/or the eyes of the watcher, even frequencies above 300 Hz become visible. This is an annoying aspect of most types of automotive rear lights based on LED technology. Many drivers can see the stroboscopic effects of the taillight of a car in front, if the distance is large enough or if the front car moves up and down quickly (e.g. driving over an unevenness). Even letting the view glide from the road scene to instruments and back brings the flicker into awareness for some drivers.

Note: Focussing a flickering light source deminishes flicker visibility, peripheral vision enhances the flicker visibility.

Note: In ophthalmology flickering light is used for example for diagnosis of the capillary damage in the eyes of patients with diabetes. Flickering light causes capillaries in the retina to change caliber which has profound effects on blood circulation as well as metabolic activity.

Note: Again industry tries anything to make sure that they can go on with the conventional practice to manufacture the cheapest, not the best light sources.

Note: There is no flicker in daylight or sunlight.