Final answer:
The iPhone 15 screen may stay on due to settings configured to keep the screen awake, such as 'Auto-Lock' and 'Raise to Wake' features, or potentially due to a malfunction or software bug. Adjusting these settings or seeking professional assistance can help resolve the issue.
Step-by-step explanation:
The iPhone 15 screen stays on due to several potential reasons. It could be due to the settings configured to keep the screen awake for longer periods, or there may be an issue where the screen is not timing out as expected. Common settings that affect this include the 'Auto-Lock' feature, which can be adjusted to make the screen turn off after a certain period of inactivity. Additionally, if the 'Raise to Wake' feature or 'Attention Aware Features' are enabled, the screen might stay on as long as it senses that someone is looking at the screen or as the phone is being held up.
The display technology, typically OLED in newer iPhones, is designed to be energy efficient even when the screen is on for long periods. However, if there's a malfunction or software bug, this might also cause the screen to remain active. If none of the settings adjustments resolve the issue, contacting Apple support or visiting an Apple Store for technical assistance might be necessary.