How does a screen work?

Original Article ↗ Hacker News Discussion ↗

Overall reception of the article and site

  • Many readers loved the page: interactive zoom “pop/pip,” ruler with sound, and overall visual polish were repeatedly praised.
  • The site is seen as a standout explainer for semi-technical readers; several people say they joined the mailing list or want to show it to teenagers.
  • Illustrations are described as “crisp” and “stunning,” on par with other high-end interactive explanations.
  • A minority finds it “coffee-table infotainment”: visually great but too shallow for truly understanding CRTs or the history and physics behind displays.

CRTs: illusion, persistence, and color

  • Several comments dwell on CRT “magic”: one bright dot scanning the raster, persistence of phosphors, and how human vision integrates it into a stable image.
  • Debate over phosphor decay times: some argue slow-motion videos understate how much of the image is visible at once; others counter that brightness decays within ~1 ms, key to CRT motion clarity versus LCD/OLED sample-and-hold blur.
  • Discussion of CRT advantages in motion (stroboscopic pulses vs continuous hold), and how VR headsets try to mimic this with backlight strobing or black-frame insertion.
  • Color CRT shadow masks are explained via parallax/pinhole-camera behavior and convergence coils. Monochrome CRTs are noted as having continuous phosphor layers and no “pixels.”
  • Vector CRTs and arcade games (e.g., Asteroids, Star Wars) are lauded for razor-sharp, extremely bright lines that modern emulation struggles to reproduce.
  • Nostalgia clashes with practicality: CRTs are heavy, noisy, and inconvenient, but many still find them aesthetically and technically “cool.”

LCD/OLED technology, efficiency, and image quality

  • Some argue LCDs reaching consumer scale is unsurprising; others emphasize the manufacturing difficulty of large, uniform, defect-free panels.
  • Modern high-end LCD TVs are considered “pretty damn good,” with fast response, wide color, and wide viewing angles; but critics stress LCD’s inherent contrast and efficiency limits due to backlight filtering.
  • Counterpoint: LED backlights can be more energy-efficient than OLED emitters, so LCDs may use less power except on very dark content.
  • OLEDs are praised for contrast, compactness, and lower power in many workloads, but concerns include burn-in and efficiency of blue emitters.
  • Some wish the article covered more: circular polarizers on OLEDs (important for black levels), common subpixel layouts (e.g., PenTile), tandem OLED stacks, and reflective/transflective LCDs.

Digital vs analog, pixels vs scanlines

  • Several commenters object to treating CRT “pixels” like fixed digital pixels; CRTs fundamentally draw analog scanlines with continuous voltage modulation.
  • Color triads and aperture pitch are acknowledged, but there’s no strict one-to-one digital addressing as on LCD/OLED.
  • Resolution flexibility on CRTs (e.g., using higher horizontal resolutions than “spec”) is highlighted as a lost capability.

Refresh model and technical nitpicks

  • The article’s claim that modern displays “light every pixel simultaneously” is challenged: LCDs and OLEDs typically refresh line by line (scanning), not globally.
  • This can be verified by filming a monitor in slow motion and observing the moving refresh band.
  • Some readers wanted deeper treatment of phosphor decay, LCD multi-layer designs, quantum-dot tradeoffs, and driving electronics.

Driving millions of pixels from a serial link

  • Multiple readers express curiosity about how a serial HDMI/DVI/DisplayPort signal becomes millions of parallel pixel voltages.
  • Explanations:
    • A scaler chip decodes the digital stream and outputs over a few high-speed differential lanes (LVDS, eDP, etc.).
    • TCON and row/column driver ICs, bonded around the glass, perform serial-to-parallel conversion and address pixels using shared row/column lines rather than individual wires per pixel.
    • This architecture makes global, instantaneous refresh impractical; scanning is inherent.

Miscellaneous observations

  • People enjoy zooming in on subpixel patterns with magnifiers, water drops, or microscopes.
  • Some initially misread the title as referring to the Unix screen program or a football “screen” play.
  • Feedback on UX: disabled chapter links are confusing without an indication of whether they’re locked, incomplete, or upcoming; the right-side ticker sound felt oddly “inside the head” to at least one reader.