The light-emitting diode, or LED, of devices like the iPhone are designed to reflect light outwards toward the user.

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As a result devices that use them need fewer LEDs (light-emitting diodes) to provide backlighting, allowing the screen to take up less room and use less power.

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There have been several attempts to develop new light-bulbs in recent years - Light Emitting Diodes (LEDs) have come a long way since they were best known for being indicator lights in electronic devices.

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