When you receive a call or receive an email, your iPhone will notify you with sound or vibration. But that's not all. The iPhone also has a function called "LED flash notification" that blinks the LED light on the back to alert you.
This LED flash notification is enabled in iOS 13 by opening the screen in the order of "Settings" → "Accessibility" → "Audio / Visual" and turning on the "LED flash notification" switch (disabled by default). .. Notifying you with light in addition to sound and vibration will prevent you from missing important calls and emails. Its brightness is so great that you will notice the notification in the light reflected by the TV or lighting fixtures.
However, LED flash notifications do not always work. It only glows when the iPhone is in sleep or locked. Even if you receive a notification while operating your iPhone, the LED does not always light up.
The LED flash will not work even if you have disallowed notifications on the lock screen. For example, if other apps flash the LED but only Twitter does not illuminate, open the screen in the order of "Settings" → "Notifications" → "Twitter", and the "Allow notifications" switch is turned on. , Make sure that "Lock screen" is checked.
For some apps such as LINE, the LED flash will not work if the "Sound" switch is turned off. For apps that want to know notifications by light, make sure that "Allow notifications", "Lock screen", and "Sound" are checked.
