The Screen — Pixels, LCD vs OLED and Touch

What you'll learn

• Your screen is a grid of pixels — a 1080 × 2400 phone has about 2.6 million. Each pixel is three tiny lights: red, green and blue. A drop of water on the screen acts like a magnifying glass, so you can see them.
• Your eye mixes them: red + green looks yellow; all three at full power look white.
• Each light has 256 brightness steps → 256 × 256 × 256 ≈ 16.7 million colours. The picture is redrawn 60 or 120 times a second (120 Hz = smoother scrolling).
• LCD: one white backlight, always on, and liquid crystals that twist to pass or block the light — so black always leaks a little light.
• OLED: every tiny light makes its own glow; black = switched off → true black, and it saves battery on dark pixels. Many phones today use OLED; many cheaper phones and most laptops use LCD.
• Touch: an invisible grid of see-through wires under the glass, checked 100+ times a second. Your finger conducts and pulls a little charge from the nearby crossings, so the phone knows where you touched. A normal glove doesn't conduct, so nothing happens; touchscreen gloves have conductive threads.