There has been customer complaints on the iPhone X and XS models that they aggravate headaches and eye strain and PWM (pulse width modulation) has been indicated as a possible contributor to this. LCD models from Apple do not use PWM, Only the OLED models do. A likely reason for PWM is that OLED is highly susceptible to image retention (burn-in). On a TV, image retention can be prevented through various techniques (e.g., pixel shift) coupled with the fact that home-theater TVs generally aren't displaying static images constantly. With smartphones static images are displayed constantly. To me it seems that OLED is a poor choice of display technology for smartphone displays. Although OLED certainly gives better quality image and battery life, it is very expensive to manufacture and requires PWM to prevent ruining the screen. I'm a huge OLED fan on home-theater TV but I don't think it makes good sense putting it on a smartphone. A smartphone is something you stare at constantly and something that can get broken from dropping. So dramatically raising the cost for OLED and having to deal with a pulsating light going off in your face seems bad choice to me. What are your thoughts?