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Old 11-17-2018, 12:33 AM   #7
DNSB
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Join Date: Jul 2010
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Device: Kobo Sage, Libra Colour, Lenovo M8 FHD, Paperwhite 4, Tolino epos
Quote:
Originally Posted by m_j View Post
About the flickering, although my cellphone can catch the flickering, but I cannot perceive the flickering with my bare eyes, so I am ok with it. However, it would be better to use other less controversial techniques. I have no idea why Kobo utilizes this controversial method on its premium model.
Hmmm... have you looked at the two main methods for controlling LED brightness? If so, you may notice that variable current has issues with non-linearity between current and brightness not to mention colour shifting as you dim the LEDs. As for the flickering, I found it interesting that we have a claim that no flickering was recorded at 50% brightness yet flickering was recorded at 100% brightness. The designs I have seen for PWM brightness control have all used a 100% duty cycle at 100% brightness so no on/off and no flickering.

I've attached two images showing light output using variable current and PWM. Sadly, the site with the original images is no longer there.
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