The Working Principle Of TFT LCD Screen

- Jul 19, 2018 -

(1) TFT is how to work the TFT is "Thin Film transistor" abbreviation, generally refers to thin-film liquid crystal display, but actually refers to the thin film transistor (matrix)-Can be "active" on the screen of each independent pixel control, This is the so-called Active matrix TFT (active matrices TFT) of the origin. So how did the image actually come about? The basic principle is simple: the screen consists of a number of pixels that emit light of any color, as long as the control of each pixel to display the corresponding color can be achieved. In the TFT LCD is generally used backlight technology, in order to accurately control the color and brightness of each pixel need to install a shutter-like switch after each pixel, when the "shutters" open when the light can be through, and "shutter" closed after the light will not be through. Of course, technically, it's not as simple as that.

LCD (liquid Crystal Display) is the use of liquid crystal characteristics (when heating for liquid, cooling crystallization as solid), the general liquid crystal has three kinds of forms:

Layered (smectic) liquid crystal, similar to clay

Filiform (nematic) liquid crystals resembling a fine match rod

A cholesterol-like (cholestic) Liquid crystal

The liquid crystal display is filiform, and when the environment changes, its molecular structure changes, which has different physical properties--that can be achieved by allowing the light to pass or block the light--the shutters of the analogy.

We know the three primary colors, so the composition of each pixel on the screen needs to be described above three similar basic components to constitute, respectively, control red, green, blue three colors. The most commonly used is the twisted nematic TFT liquid crystal display (Twisted nematic Tft LCD), the following figure is explained in this type of TFT monitor working principle.

The existing technology is very different, and we will describe it in detail in the second part of this article. There are grooves on the upper and lower floors, where the grooves in the upper layers are arranged vertically, and the lower levels are arranged horizontally.

When no voltage LCD in the natural state, from the light-emitting map 2a twisted to the column TFT display schematic diagram layer divergence of light through the interlayer, will occur 90 degrees of distortion, which can be smoothly through the lower level.

When a voltage is added between the two layers, an electric field is generated, and the liquid crystal is arranged vertically so that the light does not twist--the result is that the light cannot pass through the lower layer. (2) TFT pixel architecture: color filter According to color divided into red, green, blue Three, sequentially arranged on the glass substrate to form a group (dot pitch) corresponding to a pixel each monochrome filter is called Sub Pixel (sub-pixel). In other words, if a TFT monitor supports the 1280x1024 resolution, at least the 1280x3x1024 pixel and the transistor are required.

For a 15-inch TFT monitor (1024x768), a pixel is about 0.0188 inches (equivalent to 0.30mm), and 0.011 inches (equivalent to 0.28mm) for a 18.1-inch TFT display (1280x1024). As you know, pixels are important to the display, and the larger the size of each pixel, the greater the maximum resolution the display may achieve. However, due to the limitations of the transistor physical characteristics, the current TFT per pixel size is basically 0.0117 inches (0.297mm), so for the 15-inch display, the largest resolution only 1280x1024.