LCD brightness and contrast control with PWM
You can use PWM but I'd definitely not risk sending it as raw PWM to the LCD - use a low pass RC network for sure. I guess the risks are not big but neither is the inclusion of a 1k resistor and a 10uF capacitor. Without the filter I can foresee some strange aliasing effects on the screen (unless the LCD has got a filter built-in but how would you know?).