Removing Flicker

Now that we have multiple cool basic light effects it is time to address one of the more annoying issues of pulse width modulated displays. They always seem to flicker. This is because lots of them have cycle rates well below 100 Hz.
At first glance it seems that the human eye can not resolve such frequencies. Indeed this is true for fixed points on the retina. However for moving objects the retinal image will also move. Thus if the cycle rate is to low the image will not appear as one line but as a series of dots. In order to observe this effect run one of the patterns of the previous experiment and move the shield in front of your eyes.

Knight Rider PWM Flicker

Knight Rider PWM Flicker

This effect is also visible if the shield is stationary and you look to the left of the shield and then suddenly to the right.

The same is visible with lots of car tail lights. I find this extraordinary annoying. So if anyone of you has a chance to fix this: read on and learn how.

3 Responses to Removing Flicker

  1. Joghurt says:

    > The same is visible with lots of car tail lights. I find this extraordinary annoying.

    Me, too! I so don’t understand what developers of such low-frequency-blinking backlights think, if their eyes are really slower than ours or what… :(

  2. B. Joe Holcomb says:

    I believe it may be time to consider a class action lawsuite! I have wrote just about every auto manufacturer that has the flicker issue-

    • I have no clue about your legal system and mass action lawsuits. However I have the feeling that this will be somewhat futile as car manufacturers probably have large legal departments. Also it seems that it is unclear for what exactly they could be sued – annoying people?? I doubt that this would have any chance for success.

      On the other side I think that marketing departments should be targeted. Not development or customer relations. Development departments might be aware of the issue but might not fix them due to cost pressure. Since I already see at least some cars that fixed this flicker issue by now I would say that cars with flickering tail lights are outdated. Spread the word. Make it public. Share it on Facebook. Tell it anyone. I assume that any marketing department that learns that their tail lights are outdated will push for a fix. Especially if it costs only some fraction of a cent per car.

      Did I mention that flickering tail lights are annoying AND outdated? Even an amateur could fix this – see my blog post ;) So they are a clear sign of sloppy and outdated engineering. To repeat it once again: flickering LED tail lights are not cutting edge technology but outdated. Any car manufacturer out there that still does not get this?

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