Everything About LCD Monitor

For a color on a pixel to get activated in an LCD monitor, a current runs through the crystals to change its state and produce color. The response time is the amount of time the crystals in the panel take for them to move to an on state from an off state. The rising response time is the amount of time it takes for the crystals to turn on, and the falling time is the time it takes for the crystals to move to an off state from an on state. The rising time tends to be very fast on LCD monitors, but the falling time is usually slower, causing a blurred effect on vivid, moving images on black backgrounds. The lower the reseponse time, the lower the blurred effect on the monitor. Today, response times also refer to the gray to gray rating that produces a lower speed than the traditional response time.

LCD monitors produce the image through a film with a current running through the pixels. This current activates the shades of color on the pixel. The problem with LCD films is that the colors are only accurately shown when the screen is viewed straight on. When the viewer is looking at it from a perpendicular angle, the colors tend to look washed out. The quality of LCD monitors is rated according to their vertical and horizontal viewing angles. The rating is done in degrees, using the arc of a semicircle with its center perpendicular to the LCD monitor. A 180-degree viewing angle means that the LCD monitor can be viewed from any angle in front of the screen. Higher viewing angles are generally preferred over lower angles.

LCD monitors can only display a single resolution, which is called a native resolution. The native resolution is the physical number of the vertical and horizontal pixels that the LCD matrix display is composed of. When an LCD computer display is set at a resolution lower than the native resolution, the monitor will use only a visible area or it will need to do extrapolation. Extrapolation is when multiple pixels are blended together to come out with a similar image to what would be displayed if the monitor were to were to show it at the given resolution. However, this can result in fuzzy image quality. Some common native resolutions are 1024×768 for 14-15″ monitors and 1920×1200 for 24″ widescreen monitors.

Color washout occurs when the R, G, and B transmittances change because the viewing angles are out of harmony. Specific colors that the human eye can recognize appear pale when the viewing angles increase. This is one of the things that LCD panels need to improve on. AUO Advanced MVA technology or AUO AMVA can increase the viewing angle up to 178 degrees, gives better image quality when viewed from oblique angles and improves color washout. The contrast ratio also dramatically increases, especially when the image is dim. The high contrast technology gives higher transmittance while retaining the optical properties of wide viewing angles and low color washout.

The layer of liquid crystal between CF substrates and TFT substrates rotates into different angles depending on the charge applied to every pixel. When a million pixels receive different charges, the panel obtains a million LC angles in the area. The LC’s standing angle within millions of pixels needs to be controlled because the LC’s optic rotation nature needs to control the amount of light that passes through the LCD panel. Light from back light unit moves from the TFT panel through the ITO electrode, which is turned by Liquid Crystal before it reaches the LCD panel on the top.

The LC angle controls the amount of light that gets rotated. Light that does not get rotated by the LC gets absorbed by the top polarizer. The function of the polarizer is to filter most of the light and allow light traveling at the right direction to pass through.

TFT-LCD is an abbreviation of thin film transistor liquid crystal display. This technology first came about in the 1960’s and continued to undergo substantial modifications until it began to be used for mass-production of laptops and notebook computers in 1991.

A TFT-LCD panel makes use of liquid crystals to control the amount of light that passes through. A basic LCD panel involves two glass panels with a layer of liquid crystal in between. The front glass panel contains a color filter while the back glass panel has transistors attached to it. The liquid crystal gets bent when voltage is applied through the transistors, and light is allowed to pass through and form a pixel. LCD panels contain a light source behind it. The color filter in the front glass panel gives the pixels their own color, and a combination of the pixels forms the image on the screen.