I think you may have a problem, because not even the same manufacturer
can guarantee the same contrast adjust across manufactured lots.

We buy a lot of LCD modules, and every batch we purchase needs a
different adjust for contrast. The back-light intensity has less variation.

I use two approaches in my products. For the less expensive ones I use a
10K trim-pot from Vo to ground, and for the more sophisticated I use an
analog voltage generator driven by a software-adjusted PWM.

I think you could use a trim-pot, or do you consider adjusting a
trim-pot a modification in the hardware?


Best regards,

Isaac


Em 22/3/2010 09:13, Marcelo R escreveu:
> Hi all,
>
> We will change our LCD supplier and we have to assure that the new LCD wi=
ll
> have the same contrast and backlight bright when I just plug it on my
> circuit, without hardware or software modifications.
>
> The problem is that i don't have any documentation and don't know the
> nominal features of the LCD we use in the moment. All i know is its part
> number "BC-1602C-SDBA-J-B-A00"
>
> I didn't found any datasheet or specification for this Part Number, the f=
ew
> information it says to me is:
>
> A - Normal Temperature Type/6:00
> S - LCD type: STN
> 1602 - 16 columns/2 rows
> B - COB Package
>
> But i'm almost sure that what really plays a role on the contrast and
> backlight bright is the following features:
> - LCD Driver Voltage =

> - Drive Method (DUTY, BIAS)
> - Drive IC =

>
> Do you know how can extract such information of the part number or another
> way to assure that the new LCD will have the sabe bright?
>
> Thanks in advance.
>   =

>

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