Display Driving Method Using Common Voltage Modulation for Sub-4um Pixels
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Solution Overview
Problem
Conventional color-sequential display apparatuses require multiple transistors and capacitors to transmit and temporarily store display data, limiting the size of pixels to above 4 um×4 um, necessitating a novel display driving mechanism for a simpler pixel design without pre-temporary data storage.
Innovation Solution
A driving method for a display apparatus that writes display and reset data into pixel units during the same frame period, modulating the common voltage during frame transitions, allowing for a simple pixel design by maintaining DC balance across liquid crystal capacitors, enabling fast frame switching and good image quality without temporary data storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple transistors and capacitors are used to transmit and temporarily store display data, then data storage function is improved, but pixel size is increased
Solution Approach 1:
The patent extracts the data storage function from the pixel unit by implementing a frame memory outside the pixel array. This allows the pixel to focus solely on display functions while the frame memory handles data storage, thereby reducing pixel size without compromising data storage capability
Solution Approach 2:
The common voltage line is designed to serve multiple functions: it provides the common voltage for liquid crystal capacitors during normal operation and simultaneously serves as a data transmission medium during frame periods. This multi-functionality eliminates the need for separate data storage components within each pixel
2Adaptability or versatility
If multiple transistors and capacitors are used in pixel design, then data transmission and storage capability is improved, but device complexity is increased
Solution Approach 1:
The patent extracts the complex data storage and transmission functions from the pixel unit and implements them in separate external circuits (frame memory and control circuits). This simplifies the pixel design to essential display functions only, reducing device complexity while maintaining full data transmission and storage capability
Solution Approach 2:
The patent employs periodic switching of transmission gates during frame periods to transfer data from the frame memory to the pixel units. This time-division multiplexing approach allows data transmission without requiring permanent storage components in each pixel, simplifying the overall device structure
3Area of moving object
If pixel size is reduced below 4 um×4 um, then area efficiency is improved, but data storage capability is lost
Solution Approach 1:
The patent extracts the data storage function from the pixel unit and implements it in an external frame memory. This allows pixels to be minimized to essential display components only, achieving sub-4um size while maintaining data storage capability through the external memory system
Solution Approach 2:
The patent introduces a frame memory as an intermediary between the data source and the pixel units. This intermediary handles all data storage and transmission functions, allowing the pixel units themselves to be extremely small while still maintaining full data storage capability through the intermediary system
Data Source
AI summary
A driving method for a display apparatus is provided. The display apparatus includes data lines, scan lines and pixel units. Each pixel unit includes a pixel electrode and a common electrode. The driving method includes the following steps: when the display apparatus enters from a first frame period into a second frame period, switching a voltage level of a common voltage from a first common voltage level to a second common voltage level, and simultaneously changing a voltage level of the pixel electrode; during a data period of the second frame period, driving the scan lines according to a scanning sequence so as to write display data transmitted by data lines into the pixel units; and during a reset period of the second frame period, driving the scan lines according to the scanning sequence so as to write reset data transmitted by the data lines into the pixel units.