Toshiba T4700CS Maintenance Manual page 56

Pressing the Fn+arrow key increases or decreases the brightness of color LCD
Check 3
panels.
Pressing the Fn+arrow key increases or decreases the contrast of STN color
Check 4
LCD.
2-36
Increases the brightness of the LCD panel.
Decreases the brightness of the LCD panel.
Increases the contrast of the STN color LCD panel.
Decreases the contrast of the STN color LCD panel.
T4700CS, T4700CT, T4800CT