I think this is a new feature in my laptop with Windows 8 to change brightness as needed and i ant to disable this option
How can i disable Windows 8 to adjust automatic brightness?
These are the easy steps to adjust the brightness of Windows 8.
1. Click Desktop on the Start Menu.
2. Find the battery icon on the lower right side of your screen. Right click it to select More Power Options.
3. On the currently profile, select Change Plan Settings
4. Click the link labeled,"Advanced Power Settings".
5. Go down and search Display and then look for Enable Adaptive Brightness.
6. Change to Off choosing “Plugged In”, “On Battery” or for both.
