Driving Method Of LCD Segment Code Screen
Aug 20, 2023| 1. Static drive method
The static driving method is the most basic method to obtain the best display quality, and it is suitable for the driving of pen-segment liquid crystal display devices. In the electrode structure of this type of liquid crystal display device, when multiple digits are combined, the back electrodes BP of each bit are connected together. In the circuit of the static driving method, the pulse signal of the oscillator is directly applied to the back electrode BP of the liquid crystal display device after frequency division; and the pulse signal of the segment electrode is generated by the synthesis of the display selection signal and the timing pulse.
When a certain display pixel is selected for display, the pulse voltage phase difference between the two electrodes on the display pixel is 1800, and a 2V voltage pulse sequence is generated on the display pixel, so that the display pixel exhibits display characteristics; when a certain display pixel is non-display When selected, the phases of the pulse voltages of the two electrodes on the display pixel are equal, and the combined voltage pulse on the display pixel is 0V, thereby realizing the display effect. This is the static drive method. In order to improve the contrast, the voltage of the pulse may be appropriately adjusted.
Advantages/disadvantages of static drive:
The advantage is that the connection between the LED display components is very simple, and all LEDs can be connected in series with only 5-6 lines, which is convenient for debugging and maintenance. The display brightness is good, and suitable driving components can be used to drive LEDs below 2 meters, which is suitable for making large outdoor digital screens.
The disadvantage is that each LED requires 1-2 driver ICs, and a display component PCB board needs to be made. The power consumption is slightly larger (5 times that of the scan drive). The cost is slightly higher (the average cost of the display driver per bit is 0.4-1 yuan higher than that of the scan driver).
2. Dynamic drive method
The advantage is that the display driving circuit is simple, 2 ICs can drive 8 LEDs below 10", and the cost is low. LEDs of various sizes can be directly connected to the main control board, driver board, and expansion board, even without using a PCB board. Low power consumption. The time-sharing scanning display mode is adopted, and the power consumption is only 1/5 of the static display.
The disadvantage is that there are many connections between the LED and the driver board (a total of 8+LEDs). When the number of digits is large, the connection and maintenance are inconvenient.
The difference between the two:
The characteristics of static driving are high contrast, high brightness, and fast response speed. The characteristics of dynamic driving are that the driving of each bit display is staggered and driven in sequence by time division, and the same driving element can be used!