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Short note: Flat panel displays

Short answer

Flat panel displays are thin, lightweight, low‑power devices. Emissive types (plasma, OLED) generate light directly; non‑emissive types (LCD) modulate a backlight. They offer sharp, geometrially correct images but may have limited viewing angles and fixed native resolution.

Write a short note on flat panel displays.

Flat panel displays are video devices that are much thinner, lighter and consume less power than a CRT. They are used in laptops, mobiles, TVs and monitors. They are divided into two classes.

Emissive displays

These convert electrical energy into light themselves.

  • Plasma panel: gas (neon-xenon) between two glass plates with a grid of vertical and horizontal electrodes; a voltage at a crossing makes the gas glow.
  • LED / OLED: an array of light emitting diodes or organic layers; each pixel emits its own light.
  • Thin-film electroluminescent display: phosphor layer glows when voltage is applied.

Non-emissive displays

These use light from outside (backlight or room light) and modulate it.

  • LCD (liquid crystal display): liquid crystal between two polarizing plates; applied voltage changes crystal orientation, controlling light passing through. A backlight (CCFL or LED) is used.
Backlight -> Polarizer -> Liquid crystal -> Polarizer -> Eye
                          (voltage per pixel)

Advantages: thin, light, low power, no flicker or geometric distortion, sharp image. Disadvantages: limited viewing angle (LCD), costlier, fixed native resolution.

✓ Answer checked by Claude Opus 5.5 (high effort)

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