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LCD Specification

Nolan Hergert edited this page Nov 30, 2024 · 37 revisions
Display Type LCD, >2" and <3"
Likely FSTN or DSTN, but maybe IBN/VA (vertical alignment) mode for darker darks.
Not: TFT (MOQ from Hannstar is 400K for custom size monochrome TFT, there may be display artifacts too) and TN (too low contrast without corrective film)
See https://github.com/nolanhergert/HeadlightBlocker/wiki/LCD-Theory
Viewing Direction 6:00, with ~15 degree bias (draw). What is view angle? (range) image
Display Mode Transmissive, normally white / positive mode
Dot Arrangement / Resolution "Easy" answer is a graphical display with one pixel per square mm. Probably 10 backplanes and 20 segments.
However can optimize portions other than directly ahead gradually down to one pixel per 5 square mm.
Trying to balance requirements of density, pin count, pupil distance compensation, and cost.
Module Size Rectangle/circle for now, >30mm and <60mm viewing dimension on each side. Eventually custom per screen maybe?
Color Monochrome
Driver IC ML1001 preferable, ML2002 is possible too
Route VCC and GND of row ML1001 separate from column-ML1001s so you can try 1/2 bias?
https://github.com/nolanhergert/HeadlightBlocker/wiki/LCD-Theory#12-bias
Operating Temp -10C - 60C
Storage Temp -30C - 80C
Back Light None
Film No diffusion film, should have high optical clarity (see-through). High transparency
Lens Material Needs to not yellow over time. Glass for prototype is fine, PC/PMMA might be preferable long term for impact resistance. Try flexible if possible.
Tolerance ± 0.20mm
Connector ~.3mm pitch is ideal, but .5mm ok. FFC probably, quite short. I don't think it needs FPC, and zebra elastomer strip disallows bending, which will happen in this form factor. Standard pinouts and voltages are fine
Voltage TODO! The "knee" voltage of display for FSTN. Needs to be able to work from 3V down to ~2.7V ideally. > 2.6V. So you can run lic down to bottom without boosting. Any disadvantages to this voltage?
Need to do the math/simulation though, haven't done that yet!
Polarizer Standard polarizer. TODO: Confirm desired polarizer orientation on back and front before and after flipping horizontally when looking at other lcd screens and reflective glare and viewing angle / direction. On your glasses the blocking flipped vertically when you flipped the lens horizontally. I bet that I can have ITO pattern the same on left and right, but need to tweak polarizer orientation between left and right. Need to confirm
ITO Trace Resistance I read 25 ohm max on ML1001. Seems minimum for what I need. Try 5-10X less if possible to see if visual artifacts form and provide backup for 25 ohm ("faster" switching freq, less power lost to resistance)

dynamic_eye_small

View of Dyneye prototype: http://www.youtube.com/watch?v=cSOoYN_iOBY

View of Dyneye blocking sun: https://www.youtube.com/watch?v=PTG62q7hMcY

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