• We recently switched our forum platform. If you experience any issues please email support@crystalfontz.com

CFAH2002A-RMC-JP backlighting issue

Fishtech

New member
We are using the CFAH2002A-RMC-JP, red characters, negative mode in a panel product that's used in a light intolerant area (i.e., bright displays are distracting and not desirable to the client). We selected the above display because red characters on a dark background seemed to be the lowest reasonable visual profile, and the product literature shows nice, crispy red letters on a more-or-less black background.

In application, we're getting a great deal of light transmission over the whole display. Characters are showing as sort of pink on a red background, rather than red on a dark background. Adjusting the contrast just makes the characters more and less visible, but doesn't seem to do anything to decrease the light transmission in the non-character areas.

Any thoughts? Is this just what these look like and that's what you get, or is there something else we can do to darken the background?
Looking for additional LCD resources? Check out our LCD blog for the latest developments in LCD technology.
 
Rambling thoughts:

The data sheet says the contrast ratio is a whopping "3". So you may not be able to do much better at extinguishing the background. You migh try a wider range of Vo (LCD voltage), perhaps a few volts negative, but I suspect it won't be a big improvement, if any.

You can put a red filter or ND filter to reduce the visibility.

You can reduce the backlight intensity by using a larger current limit resistor.

You could investigate the OLED/PLED light emitting displays (CFAP2002A-Y-JCV), and set the brightness level to your customer's liking, or set it for best life and use ND filter to get the brightness you need.
 
Top