Lenovo A1 Tablet - Manual (Page 6)

"Power off " and touch "OK" to power off your IdeaPad Tablet A1-
07.
*For the 3G-enabled version, be sure to insert or remove the SIM
card in the Power off mode. Doing so when the device is on may
damage the SIM card.
1-4 Turning Screen Backlight On/Off
Turning Screen Backlight On
In the standby mode, you can tap the "Power" button on the upper
right of the IdeaPad Tablet A1-07 to "wake" the screen up. The
device's screen will then light up, indicating that the backlight has
been turned on.
Turning Screen Backlight Off
If your IdeaPad Tablet A1-07 is powered on and you do not use it
temporarily, you can tap the "Power" button on its upper right to
turn off the screen backlight. Your IdeaPad Tablet A1-07 will enter
the standby mode to save power.
1-5 Screen Lock/Unlock
Lock Screen
Auto Lock
You can set Screen timeout in under " Settings". If
there is no operation within the preset standby time, then the
screen backlight will automatically turn off, and the device will be
locked.