Viipemärgid

Viipemärgid, often translated as "flicker marks" or "wave marks," are a phenomenon observed in certain types of visual displays, particularly early cathode ray tube (CRT) televisions. They manifest as subtle, fleeting lines or patterns that appear to flicker or wave across the screen, especially in areas of high contrast or rapid motion. This effect is not a defect in the content being displayed but rather a characteristic of the technology used to create the image.

The origin of viipemärgid lies in the way CRT screens generate images. An electron beam scans across the phosphorescent screen, exciting pixels to produce light. The speed and precision of this scanning process, combined with the persistence of the phosphor material and the refresh rate of the display, can lead to these transient visual artifacts. In essence, the eye perceives these marks as the individual scan lines briefly persist or interact in the viewer's perception.

Modern display technologies, such as LCD, LED, and OLED, do not produce viipemärgid because they operate on fundamentally different principles. These technologies do not rely on scanning electron beams. Instead, each pixel is individually controlled and updated, eliminating the interlacing or scanning artifacts characteristic of CRTs. Consequently, viipemärgid are largely a relic of older display technology and are rarely encountered on contemporary screens.