Publish Time: 2024-03-29 Origin: Site
The LCD display is mainly composed of two transparent organic thin films, the structure group is filled with liquid crystal liquid between glass, and a layer of the conductor is coated on the bottom transparent film, which can effectively form conductive electrodes. Most importantly, after the electrode is charged, a corresponding electric field effect can be formed with the lower conductor, the light transmittance of the liquid crystal will also change, and the external light will be absorbed to establish a shape display similar to the shape of the electrode.
l Drive voltage
l Electrode connection
l Passive Matrix Electrode Arrangement
l Dynamic Drive Technology of Passive Matrix
(1) The LCD display will be electrolyzed under DC voltage, so it must be driven by AC and limit the amount of DC component of AC to no more than tens of millivolts.
(2) Since the change of the optical properties of the LCD display under the action of the electric field, the elastic deformation depends on the liquid crystal as an elastic continuum, and the response time is long. Therefore, the influence of the AC driving voltage does not depend on the transmission rate of the liquid crystal at a frequency whose peak value is less than 103Hz. Variation of it is only related to the RMS value of the applied voltage.
3) The liquid crystal cell is a capacitive load, which is non-polar and the effect of positive and negative pressure is the same.
The LCD display device can be divided into multiple parts on the display pixel. The latter is divided into the passive matrix and the active matrix. Segment display pixel means that the display pixel is a long strip, also called a penned segment, the most common one is seven segments the display shows numbers, English letters, Chinese characters, etc. The capacity is static, similar to the digital tube, but the power consumption is relatively small compared to the core tube, which is very low.
The passive matrix consists of two sets of ITO linear electrodes etched inside the LCD display in the X and Y directions. Pixels are placed at the intersection of the X and Y electrodes. Usually, the x-direction electrodes are called row electrodes, also called scan electrodes. The y-direction electrodes are called column electrodes, also called signal electrodes. Typically, electrodes have no gaps between rows or columns. In an active matrix, each LCD display pixel is connected to an active device (diode, transistor, or FET). The matrix electrodes and active devices are located on the lower glass substrate, while there is only one common electrode on the upper glass substrate. For a passive matrix liquid crystal display device, the driving voltage is synthesized by the synchronously input row and column electrode voltages. The driving voltage is a driving technology directly applied to the pixel electrodes so that the liquid crystal display directly corresponds to the driving voltage signal. Also known as the direct-drive method. According to the different addressing modes, it can be divided into static drive and dynamic drive. Static driving refers to the display state when a voltage signal is applied to the front and rear electrodes of the pixel, and the display state when no voltage is applied. When the number of leads is relatively small, it is usually simple to use a static drive and does not require a field scan.
(1) Scan each pixel on the line at the same time, and the voltage of all pixels on the line disappears after scanning, which is different from the point-by-point scanning of CRT.
(2) Pixels in each row of the LCD display are selected in different periods, which may result in uneven image brightness.
(3) Duty cycle: The ratio of the electrode gate time to the frame period of each scan line. It is equal to the inverse of the scan electrode. The more scanning lines, the smaller the duty cycle, and the smaller the response of the liquid crystal according to the power accumulation effect of the LCD display device; otherwise, the larger the response.
The above is the relevant content about LCD display drive technology. If you are interested in an LCD display, you can contact us. Our website is www.smartboardfactory.com.