Final answer:
Each pixel on a 4K TV consists of three subpixels, with filters for the primary colors red, blue, and green. These subpixels are illuminated by a backlight and controlled by liquid crystals to produce a wide range of colors.
Step-by-step explanation:
Each pixel on the newest 4K resolution TVs and monitors is actually made up of four subpixels. More specifically, in flat screen LCD televisions, each pixel comprises three cells with red, blue, or green filters, each controlled independently. These cells are not yellow but are capable of combining the light they pass to produce a range of colors, including yellow, when different intensities of red, blue, and green are mixed together. The presence of a large light at the back of the TV illuminates the liquid crystals layered over each subpixel's filter. When the voltage applied to a liquid crystal is varied, it changes the intensity of the light passing through, thus controlling the pixel's overall color and brightness.