Bias lighting

[1][2] The purpose of bias lighting is to reduce the perceived brightness of the display as a result of the contrast with the slightly illuminated area around it.

[2] In 2002, Philips Consumer Electronics developed and patented[3] a lighting system that allowed the background illumination to follow the brightness and color of the TV image.

As of the 2000s, bias lights often use LEDs, attach to the backside of flat-panel displays, and draw power from a USB port.

[2] Some bias lighting kits even use a webcam pointed at a TV or monitor screen to read colors and change television backlights accordingly.

[1][2] In home cinema, bias lighting that is no brighter than 10% of the display's brightest spot[2] and with a color rendering index of at least 90 is recommended.