What are quality factors of display devices? Discuss types of display devices.

Display quality decides readability of X-ray images and reports — critical in hospitals.

Quality factors:

1. Resolution — Pixels (1920×1080 Full HD); higher = sharper text/X-ray detail.
2. Size and aspect — 22–27 inch, 16:9 for reports; larger for radiology.
3. Brightness/Contrast — cd/m² and ratio (1000:1); high contrast shows subtle fractures.
4. Colour accuracy/gamut — True skin/X-ray tones; IPS panels better than TN.
5. Response/Refresh — ms and Hz; 60 Hz fine for office, higher for video.
6. Viewing angle and eye care — IPS wide angle; low blue-light/flicker-free for long duty.

Types:

1. CRT — Old electron-gun tubes; bulky, flicker, now obsolete.
2. LCD (CCFL) — Liquid crystal + backlight; slim, low power; standard office upgrade from CRT.
3. LED (LED-backlit LCD) — Bright, thin, energy-saving; most common in Nepal offices/hospitals today.
4. Plasma — Gas cells, vivid but heavy/power-hungry; discontinued.
5. OLED — Self-lit pixels, perfect black, best for imaging but costly.

For exam: recommend LED-IPS Full HD for wards (cost + eye care), high-resolution IPS/OLED for radiology.