Depending how you use your phone, you may want to set some form of automatic screen lock to prevent unauthorized access. If a screen lock has been set, the screen locks when your phone's display goes to sleep.
To adjust your phone's lock settings:
- From a Home or All Apps screen, touch the Settings icon
. - Touch Personal > Security > Screen lock.
- Touch the type of lock you want and follow the onscreen instructions.
If you have previously set a lock, you must enter the pattern, PIN, or password to unlock the lock settings.
You can choose among these lock options, listed in approximate order of strength:
- Slide provides no protection, but lets you get to the Home screen quickly, or open Camera and start taking pictures immediately.
- Face Unlock lets you unlock your phone by looking at it. This is the least secure lock option.
Improving Face Unlock: After you select Face Unlock and set it up, you can improve its performance by capturing your face data again under different lighting conditions. To do so, choose Settings > Security again, and then choose Improve face matching. This option is available only when your screen lock is currently set to Face Unlock.
- Pattern lets you draw a simple pattern with your finger to unlock the phone. This is slightly more secure than Face Unlock.
- PIN requires four or more numbers. Longer PINs tend to be more secure.
- Password requires four or more letters or numbers. This is the most secure option, as long as you create a strong password.
Password tips: For best security, specify a password that is
- A least 8 characters long.
- Contains a mixture of numbers, letters, and special symbols
- Doesn't contain any recognizable words or phrases.
Related settings
To change when your phone goes to sleep, touch the Settings icon 
> Device > Display > Sleep.
To see your passwords when you input them, touch the Settings icon > Personal > Security > Make passwords visible.