Raster display
A raster display is the most common type of CRT display. It draws an entire grid, a horizontal line at a time, constantly varying the intensity of the beam to draw the image. CRT television sets, video terminals, and computer monitors are all forms of raster display. Viewed up close, you can make out their distinct horizontal lines.
Even when displaying theoretically crisp digital images made of pixels, they somewhat blur them together, connecting them horizontally as the beam is relatively slow to increase and decrease its intensity to match the value of each new pixel. (Dithering exploits this.) Conversely, they leave a gap between each row. Because they glow, they have dimmer areas tapering off around each bright point, somewhat compensating for these gaps, and making for a slightly fuzzy image.
This is all less noticeable when viewed from a sensible distance, as with watching television. But people using video terminals or home computers, sitting close enough to read the text, can see the scanlines.
CRT displays: Oscilloscope | Raster display | Vector display
