High speed LCD backlight modulation and sync

[Benjamin Smith]

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Hey microscopists,

For anyone who needs to do high-speed monitor modulation, or sync the
backlight of a monitor to a peripheral device (such as a 2P microscope), I
just tested the Qualia bare driver from Adafruit driving the LG LP097QX1 -
iPad 3/4 Retina Display, and it worked exceptionally well:
Driver board:  https://www.adafruit.com/product/1716
Monitor: https://www.adafruit.com/product/1751

There are a pair of nice through-holes in the driver board to allow you to
attach your own external PWM (see photo - http://bit.ly/2pdsJYp).  I then
measured the on and off slew rates of the LCD backlight using a PMT and
found both to be well under a microsecond:
Backlight rise time (ns): http://bit.ly/2ovcgyj
Backlight fall time (ns): http://bit.ly/2onTJnO
Original test scan (25 ns pixels): http://bit.ly/2p7GoQG

For details on the measurement, an Arduino was used to drive both a 2P
microscope (line sync output to microscope) and the LCD backlight (PWM
output to driver), so that the two would stay more or less perfectly in
sync.  One hundred 2048x2048 scans were summed together to make the
"original test scan" image, and then the sum projection was binned in the
Y-axis to create the rise time and fall time intensity profiles.

If you have any questions, please feel free to ask.

Cheers,
   Ben Smith

--
Benjamin E. Smith, Ph. D.
Imaging Specialist, Vision Science
University of California, Berkeley
195 Life Sciences Addition
Berkeley, CA  94720-3200
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https://vision.berkeley.edu/faculty/core-grants-nei/core-grant-microscopic-imaging/