LCD for handset and 3D printing help needed

[Mychaela Falconia]

Hi Serg,

> A couple of notes. Would it be possible to extend the spacer by 1 mm
> outside of the LCD footprint?

Do you mean extend by 1 mm total (extra 0.5 mm on each side), or have
an extra 1 mm on each side?  I would hope that adding just 0.5 mm on
each side should be sufficient - this way there is a full 1 mm of
outer wall at the points where the alignment pins go in.  Or do we
need even more outer wall at those points?

> On the inside at the bottom legs it will be
> just 0.4 mm wall for the pin, with +/-0.1 mm precision it is too close. I
> was thinking that making a notch instead of a hole would be a better
> option. This way I can have reasonable margins on outer side.

Yes, with my original idea the inner wall at the bottom pin hole would
only be 0.2 mm or so (if we leave another 0.2 mm of margin), so that
inner wall would essentially disappear at the widest point of the hole.
You are saying to just replace the hole with a notch, right?  Probably
a good idea.

> I have done a quick draft, does it look like a good candidate?
> https://drive.google.com/file/d/1Xd6pzuXVFUHUF1dC9Sl3Gq-ViYBu-rKJ/view?usp=sharing

Unfortunately I am a cave-dwelling neanderthal and have no idea what
to do with an STL file. :(

> How much space do we have under the LCD

I don't understand the question.  Without the proposed spacer under
consideration, there is essentially zero space under the LCD module if
it is pressed against the PCB - the module is misdesigned in my
opinion.  As to how much space under the LCD we need to *create* by
way of our spacer, my target is 1.5 mm, so we can accommodate a Molex
51296-4594 connector for the FPC tail (1.30 mm height above the PCB,
the thinnest I could find that is compatible with this LCD module's
tail configuration) with a little bit of margin.

> and can we have the spacer sticking
> outside of the screen footprint?

Yes, we can make the spacer footprint extend a little wider than the
38.40 mm width of the LCD module, but we should only extend it as much
as absolutely necessary.

> I made it 2 mm wide

Does it mean that the inner edge of each wall coincides with the
innermost point of the alignment pin on that side while the outer edge
of each wall extends 0.5 mm past the outer edge of the module shell?

> and 1.5 at the bottom
> to accommodate the flat cable.

We need the space not so much for the flat cable (FPC tail), but for
the PCB-mounted connector into which this FPC tail will need to go.

At this point the most effective way for you to help this project
would be to receive a physical LCD module from me and start
experimenting with it hands-on.  Where should I send it?

M~