Using phone in the night is the familiar habit of many people nowadays. Especially the flagship mobile phone such as Galaxy Note9 S9 PhoneX G20 and others have high battery capacity and can install many exciting games.
So that many people use phone to play game and web every night.
This may cause eyes feel tired during night and have trouble in sleeping after long time.
The main reason of these is due to blue light (Blue light is a range of the visible light spectrum coming from a variety of technologies including computers smartphones televisions and lights.)
To reduce blue light can protect eye and improve sleep.

The Note9 - S9 screen filter application is to reduce the effect of blue light by blue light filter This will make you comfortably when reading or playing on phone by eye care function.
There are some features:

Turn On or Off Quickly and Easily
You can choose to show or hide a filter icon in the status bar making it easy to adjust the settings.
Screen Dimmer
You can adjust your screen brightness accordingly. Get better reading experience.
Contrast
Adjust the contrast of screen
Filter to protect your eyes.
Turn ON light filter (blue light red green) to start protecting your eyes! Especially effective when you are to stare at the smartphone screen for longer hours & during night.

Let protect your eyes for your beautiful eyes!