Powered by Invision Power Board


Forum Rules Forum Rules (Please read before posting)
  Reply to this topicStart new topicStart Poll

> LCD Problems
straightexhaust
Posted: December 21, 2006 08:41 pm
Reply to this postQuote Post


Sr. Member
*****

Group: Trusted Members
Posts: 369
Member No.: 2,704
Joined: June 14, 2005




Ok I just finished making on of these parallel port lcds I bought a lcd with black background with red text. The problem is tht the text isn't bright enough and when i dim the backlight with a pot tht i soldered between the board and the positive led lead it also dims the text. The chip for the lcd is the same as mentioned on the site above. I dont necessarily need the backlight i just want the text to be brighter.

Thanks Jason
PMEmail Poster
Top
kellys_eye
Posted: December 21, 2006 08:48 pm
Reply to this postQuote Post


Forum Addict ++
*******

Group: Spamminator Taskforce
Posts: 10,679
Member No.: 2,735
Joined: June 21, 2005




LCDs don't generate their own light, they only reflect what's already available - failing that they can, as your display does, they pass or block a fixed backlight.

You can only make the display as bright as the backlight goes.

You could always change the backlight LED to something brighter....



--------------------
May contain nuts
PMEmail PosterYahoo
Top
straightexhaust
Posted: December 21, 2006 09:06 pm
Reply to this postQuote Post


Sr. Member
*****

Group: Trusted Members
Posts: 369
Member No.: 2,704
Joined: June 14, 2005




But the broblem is the contrast the backlight illuminates each little segment and you can only read the text at an angle not straight on.
PMEmail Poster
Top
Gorgon
Posted: December 21, 2006 10:24 pm
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 3,009
Member No.: 3,861
Joined: December 18, 2005




Have you got a contrast adjustment, and tuned it to max contrast?

Is the backlight LED current nominal?

TOK wink.gif


--------------------
Light travels faster than sound. That's why some people appear bright until they speak!
PMEmail Poster
Top
straightexhaust
Posted: December 21, 2006 10:34 pm
Reply to this postQuote Post


Sr. Member
*****

Group: Trusted Members
Posts: 369
Member No.: 2,704
Joined: June 14, 2005




how would i adjust contrast
PMEmail Poster
Top
Gorgon
Posted: December 21, 2006 10:38 pm
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 3,009
Member No.: 3,861
Joined: December 18, 2005




Post the type number and manufacturer of your display, I'll need this to get the datasheet.

TOK wink.gif


--------------------
Light travels faster than sound. That's why some people appear bright until they speak!
PMEmail Poster
Top
kellys_eye
Posted: December 21, 2006 10:55 pm
Reply to this postQuote Post


Forum Addict ++
*******

Group: Spamminator Taskforce
Posts: 10,679
Member No.: 2,735
Joined: June 21, 2005




^yup, there's usually a pin on the connector dedicated to the contrast voltage.



--------------------
May contain nuts
PMEmail PosterYahoo
Top
Gorgon
Posted: December 21, 2006 11:09 pm
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 3,009
Member No.: 3,861
Joined: December 18, 2005




You can use this circuit user posted image

The ssc2b16 datasheet say Vdd - Vo = 4.4V -> 0.6V from 0V(Vss) not much but the contrast range is not very great on this displays. I suppose it is way too dark now with 0V in.

TOK wink.gif


--------------------
Light travels faster than sound. That's why some people appear bright until they speak!
PMEmail Poster
Top
Audioguru
Posted: December 22, 2006 01:40 am
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 1,566
Member No.: 6,129
Joined: August 25, 2006




Red on black??
I have an LCD clock with big black numbers on a light grey background. Easy to see.
A backlight or contrast control isn't needed.
It operates from a 1.5V button cell.
PM
Top
tekwiz
Posted: December 22, 2006 09:51 pm
Reply to this postQuote Post


Forum Addict ++
Group Icon

Group: Moderators
Posts: 28,711
Member No.: 5,746
Joined: July 24, 2006




Jason probably has one of those transmission type of 'reversed' LCD, where the segments become clear when energized, & the background remains black. They work like the regular kind of LCD, the difference is in the polarising filter, & how it is aligned. Most LCDs suffer from poor off-axis visibility. Make sure that your backlight isn't made to run from a higher voltage than you are supplying, it may need 12vdc for full brightness. Your display may also have a faulty polarising filter, although that is unlikely. cool.gif


--------------------
Trouble rather the tiger in his lair, than the sage among his books.
For to you, kings & armies are things mighty & enduring.
To him, mere toys of the moment, to be overturned at the flick of a finger.

Fortuna favet fortibus.
PMEmail Poster
Top
straightexhaust
Posted: December 24, 2006 05:36 pm
Reply to this postQuote Post


Sr. Member
*****

Group: Trusted Members
Posts: 369
Member No.: 2,704
Joined: June 14, 2005




Thanks for all the help but....sadly its now fried so im going with the typical black on green style w/ backlight. Ill order that today. I had the red one hooked up to my pc and everything and even had pc specs scrolling across it but the contrast sucked so im going to buy the black on green style. Thanks, Jason
PMEmail Poster
Top
0 User(s) are reading this topic (0 Guests and 0 Anonymous Users)
0 Members:

Topic Options Reply to this topicStart new topicStart Poll

 


:: support us ::




ElectronicsSkin by DutchDork & The-Force