A computer monitor is an output device that displays information in pictorial form. A monitor usually comprises the display device, circuitry, casing, and power supply. The display device in modern monitors is typically a thin film transistor liquid crystal display (TFT-LCD) with LED backlighting having replaced cold-cathode fluorescent lamp (CCFL) backlighting. Older monitors used a cathode ray tube (CRT). Monitors are connected to the computer via VGA, DVI, HDMI, DisplayPort, Thunderbolt, or USB Type-C cables.
Early electronic computers (such as the ENIAC) used vacuum tube displays and electro-mechanical printers. The first computer monitors used cathode ray tubes (CRT) and were very large and expensive. CRT monitors were the only option available until the late 1970s when CRT technology was improved with the development of the first inexpensive, mass-produced monochrome (black and white) CRT, the IBM 5151. This was followed in 1981 by the color IBM 5153. In 1984, the Compaq SLT/286 introduced the first 16-color CRT, which allowed for much more flexible graphics capabilities than monochrome CRTs. The Apple Macintosh II was the first personal computer to offer an internal color video display, using a 12-bit RGB color palette. The Macintosh II also introduced the first color LCD in a personal computer, the Apple Color Display, which used a passive matrix STN LCD panel.
The first mass-produced color CRT monitor was the IBM 8514, introduced in 1987. CRT monitors were very heavy, bulky and power-hungry compared to modern LCD monitors. The Apple Macintosh Portable was the first battery-powered portable computer with a built-in color LCD in 1989. The first TFT-LCD was the IBM 8514/A, introduced in 1987. The first commercially available color TFT-LCD was the Sony 12.1″ Trinitron, introduced in 1997. The first laptop with a color TFT-LCD was the IBM ThinkPad 770, introduced in 1999. The first TFT-LCD with LED backlighting was the Apple Cinema Display, introduced in 1999. The first widescreen TFT-LCD was the Dell UltraSharp 2001FP, introduced in 2001. The first consumer TFT-LCD with LED backlighting was the Sony BRAVIA KDL-40W2000, introduced in 2005. The first OLED-based computer monitor was the Sony XEL-1, introduced in 2007.
LCD monitors have several advantages over CRT monitors. They are lighter, use less power, generate less heat, and are much thinner. They also do not suffer from screen burn-in. However, LCD monitors are subject to image retention, ghosting, and backlight bleeding. OLED monitors do not suffer from these issues, but they are more expensive.
The resolution of a monitor is the number of pixels in the horizontal and vertical dimensions. The aspect ratio is the ratio of the width to the height of the display. The native resolution is the resolution of the display panel. The dot pitch is the distance between the centers of two adjacent pixels. The refresh rate is the number of times per second that the image is refreshed on the screen. The response time is the time it takes for a pixel to go from black to white and back to black again. The contrast ratio is the ratio of the luminance of the brightest white to the darkest black.
The typical resolutions for computer monitors are 640×480, 800×600, 1024×768, 1280×1024, and 1600×1200. The aspect ratios for computer monitors are 4:3, 5:4, and 16:9. The typical refresh rates for computer monitors are 60 Hz, 75 Hz, and 85 Hz. The typical response times for computer monitors are 5 ms, 8 ms, and 12 ms. The typical contrast ratios for computer monitors are 300:1, 400:1, and 500:1.
Monitors are typically manufactured by LG, Samsung, AUO, Sharp, and Chimei.