Kuvaputkinäyttö

Kuvaputkinäyttö, often abbreviated as CRT (Cathode Ray Tube) from its English name, is a type of display technology that was dominant for televisions and computer monitors for much of the 20th century. It works by firing a beam of electrons from an electron gun at the back of the tube. This beam is then deflected by magnetic fields, controlled by deflection coils, to scan across the inside surface of the screen. The inner surface of the screen is coated with phosphors, which emit light when struck by the electron beam. The intensity of the electron beam is modulated to create different shades of color, with red, green, and blue phosphors arranged in a pattern (often as triads or stripes) to create the full spectrum of colors. Three electron guns are typically used, one for each primary color, to paint the image line by line, and frame by frame, onto the screen. While offering good contrast and color reproduction for their time, CRT displays are bulky and consume significant power compared to modern flat-panel displays. Their susceptibility to magnetic interference and the inherent limitations in refresh rates also became drawbacks. They have largely been replaced by LCD, LED, and OLED technologies due to their thinner profiles, lower power consumption, and superior resolution capabilities.