MobileRead Forums - View Single Post - Kobo Clara HD and Libra 2 Comparisons and Questions

DNSB · 12-28-2021, 02:32 PM

I just tried that waving hand suggestion on my Kobo Forma which does have a PWM front light. The Forma uses 1KHz PWM and even in a dark room waving a pencil in front of the display, I do not see any flickering/strobing. I then tried using a photodetector good up to 130KHz to detect any variation. I could notice a very minor effect on the oscilloscope display but given even moderate persistence in the phosphors used to convert the LED light to white, that was pretty much as expected.

12-28-2021, 02:32 PM	#7
DNSB Bibliophagist Posts: 36,753 Karma: 146617620 Join Date: Jul 2010 Location: Vancouver Device: Kobo Sage, Libra Colour, Lenovo M8 FHD, Paperwhite 4, Tolino epos	I just tried that waving hand suggestion on my Kobo Forma which does have a PWM front light. The Forma uses 1KHz PWM and even in a dark room waving a pencil in front of the display, I do not see any flickering/strobing. I then tried using a photodetector good up to 130KHz to detect any variation. I could notice a very minor effect on the oscilloscope display but given even moderate persistence in the phosphors used to convert the LED light to white, that was pretty much as expected.