TFT liquid crystal display is widely used because of its high contrast, strong sense of layering, and bright colors. Today we will popularize the driving method of TFT liquid crystal display devices. I hope it will be helpful for everyone to understand TFT liquid crystal display:

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According to the writing mechanism of the liquid crystal display device and the arrangement of the display pixel electrodes, the basic conditions for driving it can be determined. There are many types of liquid crystal display devices, so the driving methods are also different.

But no matter what type of device or different driving method is used, they are all used to adjust the phase, voltage, peak value, frequency, timing, effective value, duty cycle, etc. applied to the pixel electrode. Parameters and characteristics establish certain driving conditions to realize display.

There are many main drivers, and only the active matrix driving method used by TFT-LCD is introduced here.

Since each pixel of the TFT-LCD active matrix liquid crystal display device has a set of active devices, it is said that the driving of this device is the driving of the active devices on each pixel.

The external circuit cannot directly apply voltage to the liquid crystal pixel. The voltage applied to the pixel is determined by the characteristics of the TFT transistor. When the on-off ratio of the transistor reaches 106Ω or more, a requirement of the on-off ratio of the liquid crystal functional pixel can be met.

The TFT transistor works like this. When the gate G of the TFT is scanned, VG will be connected to a positive high pulse. At this time, the source signal of the synchronous input addressing is a center value The address data voltage VLD of VC will always be lower than the amplitude of the VG strobe pulse, and the transistor of the TFT is turned on. There is a path from the source to the drain of the liquid crystal pixel, and the voltage is applied to the liquid crystal pixel electrode and the compensation capacitor electrode. Even if the applied electric field is removed at this time, the voltage applied on the pixel will remain for a considerable time due to the effect of the capacitor, until the next strobe comes. If the capacitance value is set so that the pixel strobe time reaches one half frame, and the address signal of the lower half frame is inverted by VC, it can be realized:

The driving waveform applied to the pixel is in AC mode;

The number of driving channels is related to the characteristics of TFT transistors, but has nothing to do with the response characteristics of liquid crystal electro-optics. This will completely solve the big problem of LCD multi-channel driving;

The driving method has no half-strobe waveform, so there is no defect such as cross effect and contrast drop;

In addition, this kind of drive will not be affected by the response speed of liquid crystal electro-optics, and can display the image of video activity without flicker or tailing.

Youyi Vision is a high-tech enterprise integrating R&D, design, production, sales and service. It focuses on the R&D and manufacturing of industrial displays, industrial-grade touch screens and optical bonding products. The products are widely used in medical equipment, industrial handheld terminals, IoT terminals and smart homes. With rich R&D and manufacturing experience in industrial display screens, industrial touch screens, and full lamination, it is a leader in the industrial control display industry.


Driving method of TFT liquid crystal