LCD - liquid crystal display. Uses layers of liquid crystal where electrical current can cause crystals to twist differently and polarizes light passing through. Combined with grooved polarized filters, can pass or block light by varying amounts. Normally, polarized filters are perpendicular. Crystal twists light entering from back to match filter in front thus passing light through. When power applied, crystal untwists to varying amounts and polarized light is block proportionally to the twist. Placed behind colored filters to give red, green, blue. Small units similar to CRT pixels set resolution limits. However, many LCDs have certain resolutions that offer best image. LCD pixels can be on or off for the full time they are active, so no flicker at lower refresh rates. On the other hand, switching individual LCD cells on/off is slower than CRT pixels unless you pay $$$$, so moving images are more likely blurred. Response time of < 16 mS. needed for video games and < 10 mS. to become unnoticable (especially with movies). Flat panel TVs often trade the flexibility of multiple resolutions for faster LCD pixel response while keeping reasonable prices. Because the light is polarized, the viewing angle is more restricted than for a crt - with above/below being even worse than side to side. + lightweight and thin. + low power 30%-50% of crt, newer led backlit 10%-30% of crt. + no heat + little flicker (dependent on backlighting) + no refresh flicker (doesn't fade between refresh) + image sharp, especially in native resolution. - motion blur because of slower refresh rate. Improved in newer displays. - "lost" pixels tend to stand out. - can experience image-peristence quickly, not be permanent. - limited climate range, not good in very cold or warm environments. - limited color depth - control of twist limited (?). - black not very black because of back-lighting + newer oled backlighting improves on this. - cost for larger screens still high - can experience burn-in but many devices include a function to slowly shift the image to avoid burn-in and image persistance. * it is suggested that you lower the contrast to < 50% for 1st 100hrs of device's life. Plasma