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CFAH2002A-RMC-JP backlighting issue


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?
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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.