Core Technology: Electrophoretic Display Principle
The core of E Ink screen is electrophoretic electronic ink, which works based on the motion of charged particles in an electric field. The specific structure and process are as follows:
Microstructure: The core layer of the screen is composed of millions of microcapsules (with a diameter approximately equal to a human hair), each containing a transparent liquid and suspended with charged particles (black and white particles for a dual color screen, and corresponding color particles for a multi-color screen).
Electric field drive: Below the microcapsule is a thin film transistor (TFT) array, and the driving IC controls the TFT to generate a directional electric field. When a positive voltage is applied, positively charged white particles move towards the top of the microcapsule, displaying white color; When a reverse voltage is applied, negatively charged black particles move to the top and display black.
Image formation: By controlling the direction of the electric field pixel by pixel, black and white (or color) particles are arranged in an orderly manner to form text and images. Due to the stability of particles, they maintain their original position even after the electric field disappears, achieving bistable display.
Addendum: The principle of multi-color screen is consistent with that of dual color screen, which only achieves multi-color display by adding colored particles with different charges and applying different voltage combinations to control particle movement.
Key components and workflow
The E Ink screen is not a single device and requires multiple components to work together. The complete system includes:
Core layer: electronic ink film (including microcapsules), front substrate (transparent electrode), rear substrate (TFT array), responsible for particle driving and image imaging;
Control components: driver IC (controls electric field direction and intensity), timing controller (coordinates pixel refresh sequence), affecting screen refresh rate and display stability;
Interface components: SPI/I2C interface (connecting to the main control board), flexible circuit board (FPC, transmitting signals), are the core connection parts of hardware development.
Complete workflow: The main control device (such as development board, mobile phone) sends display instructions → the driver IC parses the instructions, controls the TFT array to generate the corresponding electric field → particles inside the microcapsule move to form a picture → power off after refreshing is completed, and the picture is retained.
The underlying reasons for technical characteristics
The core characteristics of E Ink can be explained by combining principles:
Low power consumption: Only power is required for particle movement (refresh), and there is no power consumption after particle stabilization. The power consumption is only 1/100~1/1000 of LCD;
Eye protection effect: No direct backlight, light reflection method consistent with paper, no blue light or flicker;
Slow refresh: It takes time for particles to move in liquid (usually 0.5~2 seconds/frame), and multiple rounds of voltage calibration are required to avoid residual images, making it unsuitable for video playback;
Residual image problem: When particles move incompletely, some pixels may leave traces from the previous frame, which need to be eliminated through "full refresh" (overall refresh), while "partial refresh" (local refresh) can improve speed but may easily leave residual images.
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