TFT-display: description, operating principle

In modern household appliances are widely usedAn element such as a TFT display. It is used in various types of devices: computer monitors, televisions, cell phone screens, video cameras and cameras, as well as many other devices. What is this technology, what are its advantages? In this article we will examine what constitutes a TFT-display, its advantages and disadvantages.

Thin-film transistor (TFT) in translation fromEnglish means thin film transistor. These elements are made of a thin film with a thickness of 0.1-0.01 microns. It is with such transistors that the TFT-matrix is controlled, it is also called "active". To passive carry liquid crystal devices. Active TFT-display, in contrast to LCD technology, has great speed, much higher definition and contrast of the image and a much larger viewing angle. These devices have no flicker of the screen, from which the eyes get tired. In active matrices, pixels generate light emission with a given color, therefore the TFT display is much brighter than passive liquid crystal matrices. All these advantages are explained by the fact that the described technology has a higher refresh rate of the image. This is due to the fact that each point of the display is controlled by a separate thin-film transistor. The number of such elements in TFT-technology is three times more than the number of pixels. Therefore, three color cells correspond to one point: red, green and blue (RGB system). For example, consider the matrix: a TFT display (color) with a resolution of 1280x1024 pixels, respectively, the number of transistors in such a device will be 3840x1024.

The first liquid crystal matrix appeared morein 1972. Since then, these technologies have evolved and changed significantly. However, all the shortcomings could not be eliminated. For example, because of the large number of pixels, it is often possible to find “broken” ones among them, that is, non-working ones. Such damaged points cannot be repaired. It is worth noting that on active matrices "broken" pixels are less noticeable than on passive devices or dual-scan displays. The constant development of TFT-technologies has significantly reduced the cost of producing such monitors, now the "expensive exotic" has become a common phenomenon. An important factor in the wide distribution of active matrices in the industry has become ease of use. Nowadays, no one will be surprised by the TFT touchscreen display, but twenty years ago it was the ultimate dream. The proliferation of touchscreen monitors was preceded by the appearance of models capable of operating in harsh operating conditions. As a result, a TFT-display was developed, combining a means of displaying visual information, as well as an input device (keyboard). The efficiency of such a system is provided by a serial interface controller. This device is connected to the monitor on the one hand, and to the serial port (COM1 - COM4) on the other. PIC controllers are used to control and decode signals from the sensor, as well as suppress "bounce". They are able to provide high speed, as well as the accuracy of determining the points of contact.