I'm planning to design HMI for a product that i want to design. but, I've questions that I couldn't find answers to:

1- TFT or OLED screens, are they reliable? do they last for > 10 years? (ok, yes within their rated temperature) (i guess they have lighting hours so i'll need also to turn them off as well until the user use them.. but on general, do they last?

2- there are controllers famous that can have libraries on the internet like SSD13xx .. the last xx i belive for different sizes as they have different gram and stuff? but are they compatible in code? for example can i find some code for ssd13xx library and run it on ssd13yy controller (of course i need to redefine columns and rows in the other one right)? but is it hard to deploy that code on different ssd controller?

3- which screen you recommend, type , brand , .. etc (in my mind new-heavin)

4- about boxes and housing for the product, is their guide for that ? for the screen? how about protection glass? which ones? supplier?

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    \$\begingroup\$ Have you designed any similar products in volume that lasted for >10 yrs witout failure? If not what makes you think one can generalize a technology without being aware of brand reputation, model number and price? ( -1 not me, just asking...) \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Jun 14 '18 at 14:30
  • \$\begingroup\$ no i didn't design a product even, im asking if someone with experience can give me hints, if you are talking about "new-heavin" part that is just an assumption from me because i think they are widely used but not sure \$\endgroup\$ – Hasan alattar Jun 14 '18 at 14:32
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    \$\begingroup\$ I suggest you read every design tear down and do some of your own and spend a year doing this before trying to design, with so many unknowns. Look at any old monitor and ask yourself, why did they do this, what are all the criteria of designing or choosing this part or using this way for electrical, mechanical, thermal and optical. This is a prerequisite to be perfect... i.e. meet spec. Of course if you enjoy learning by failure go ahead,. \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Jun 14 '18 at 14:44

OLED is horrible for long life, it degrades in storage and just degrades faster in use, don't go there. TFT or similar is the way to go, but run the (LED) backlights at maybe half or rated current, it will be a bit dim, but will last much better.

The last display driver part number do not really refer to sizes and while the chips are mostly broadly similar they are generally NOT fully compatible, and even when the chip is the same you will usually find that you need a different initialisation to get things like Vcom right for contrast and the gamma stuff if you change the module manufacturer.

Best bet is to anticipate needing to change screen every few years and make sure that there is a way for your front panel to tell the system software what it is fitted with, because you will be having to change screens.

We don't do shopping questions here, and besides anyone I would recommend today might be gone tomorrow.

Look into "Optical Bonding" for panel to glass interfaces, it makes 'em look good.

I would note that high rel design for long service can be somewhat specialised, attention to ESD, EFT, component lifetime Vs temperature, derating everything, attention to ringing on signal lines, PCB footprints, PCB surface finish (If not doing fine pitch or BGA then gold is NOT a good idea), vibration modes.... The list goes on, do you actually have the experience to pull this off?

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  • \$\begingroup\$ no experience, new to the field.. i guess i would go for somthing like 16x2 modules for now while experimenting TFT designs for a while, thank you very much all the info was helpful \$\endgroup\$ – Hasan alattar Jun 14 '18 at 15:04

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