Apple is planning to start using its own custom displays in mobile devices as early as 2024, an effort to reduce its reliance on technology partners like Samsung and LG and bring more components in-house.The company aims to begin by swapping out the display in the highest-end Apple Watches by the end of next year, according to people with knowledge of the matter. The screens upgrade the current OLED standard to a technology called microLED, and Apple plans to eventually bring the displays to other devices, including the iPhone.