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OT: LCD BIAS understanding

Started by Unknown June 22, 2005
Hi guys,

 

Firts off all, thansk for your're replies. Secondly as mentioned I could not
get my lcd working with an MSP so I choose for renesas, sorry. And that did
the trick for me very easy. But as far as understanding the whole topic..
nah. Sorry.

 

As far I can see the bias is indeed for setting the contrast but that is in
conjuction with the waveform. And that is where Ti could not help me,
unortunatly.

 

But as mentioned thanks.

 

b.t.w al thanks for the document I'll go though it and hopefully this will
answer my questions. Thanks guys.

 

martijn 

 

  _____  

From: msp430@msp4... [mailto:msp430@msp4...] On Behalf Of
Onestone
Sent: woensdag 13 juli 2005 14:41
To: msp430@msp4...
Subject: Re: [msp430] OT: LCD BIAS understanding

 

Well according to some texts I have it will destroy the crystals,  which 
is a reasonable interpretation of making the pixels non viewable I 
guess. hey, I didn't profess to be an expert.

Al

Lou C wrote:

>>LCD crystals require a AC drive signal, DC
would kill them.
>>    
>>
>
>Really?  What do you mean "kill them"?  I would think an improper
DC bias 
>MIGHT make the segments non-viewable, but not destroy the LCD.
>
>Lou
>
>
>
>
>.
>
> 
>>  Terms of Service. 

 

  _____  






Beginning Microcontrollers with the MSP430

Lou C wrote:
>>LCD crystals require a AC drive signal, DC
would kill them.
> 
> 
> Really?  What do you mean "kill them"?  I would think an improper
DC bias 
> MIGHT make the segments non-viewable, but not destroy the LCD.

I've heard that sustained DC across an LCD unit does some kind of 
electrolysis thing to the electrodes.  With AC the electrolysis effects 
during any half-cycle cancel out on the next half-cycle before any harm 
is done, but with DC there may be a point of no return where the display 
is ruined.

I would expect at least some LCD manufacturers to have something about 
this up in their Web stuff.  If they don't, some engineering schools might.


-- 
                      Tom Digby
                      http://www.well.com/~bubbles/