why is my galaxy s4 mini screen using so much battery

[AC Question]

I have recently noticed my battery draining much more quickly, when I checked battery usage in my settings it says my screen is using 48% of my battery

 

[Finn Henderson]

A screen will usually use a fair bit of power (depending on the type of screen). Some screens don't need to be very bright set to be visible, also contributing to low power usage.
Your screen either just uses a lot more power than some in general; or you have it set to maximum brightness settings