Array Substrate Frame Refresh Lines for Back Light Utilization
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Solution Overview
Problem
Conventional Field Sequential Color (FSC) type TFT-LCDs suffer from low back light utilization efficiency due to the need to turn off the back light during row scanning and liquid crystal response periods, leading to reduced image brightness and increased power consumption, especially at high frame frequencies and resolutions.
Innovation Solution
The array substrate incorporates frame refresh lines and working storage elements to separate row scanning signal refresh from image refresh, allowing the back light to remain on during the next image frame period by storing image voltage signals in working storage capacitors and controlling display refresh switches with frame refresh signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If row scanning and liquid crystal response are performed during each image sub-frame period, then image refresh is completed, but back light must be turned off during these periods causing low utilization efficiency
Solution Approach 1:
The pixel electrode is divided into a display electrode and a storage electrode. The display electrode receives image voltage signals during row scanning for display refresh, while the storage electrode holds the voltage during back light illumination. This segmentation allows independent control of signal input and voltage holding, enabling back light to remain ON during row scanning without causing color mixing.
Solution Approach 2:
Image voltage signals are pre-input to the pixel electrode during row scanning before the back light turns ON. The liquid crystal response is completed during the row scanning period, so when the back light turns ON, the image is already ready for display. This preliminary action eliminates the need to turn off the back light waiting for liquid crystal response.
2Illumination intensity
If back light is turned off during row scanning and liquid crystal response periods, then color mixing is prevented, but image brightness decreases
Solution Approach 1:
The pixel electrode is divided into a display electrode and a storage electrode. The display electrode receives image voltage signals during row scanning for display refresh, while the storage electrode holds the voltage during back light illumination. This segmentation allows independent control of signal input and voltage holding, enabling back light to remain ON during row scanning without causing color mixing.
Solution Approach 2:
The back light remains continuously ON throughout the entire image sub-frame period, including during row scanning and liquid crystal response. The segmentation of the pixel electrode ensures that continuous back light illumination does not cause color mixing, as the display electrode already has the correct voltage applied during row scanning. This continuous illumination improves image brightness and back light utilization efficiency.
3Manufacturing precision
If high frame frequency and high resolution are implemented, then display quality is improved, but back light utilization efficiency decreases further
Solution Approach 1:
The pixel electrode is divided into a display electrode and a storage electrode. The display electrode receives image voltage signals during row scanning for display refresh, while the storage electrode holds the voltage during back light illumination. This segmentation allows independent control of signal input and voltage holding, enabling back light to remain ON during row scanning without causing color mixing.
Solution Approach 2:
Image voltage signals are pre-input to the pixel electrode during row scanning before the back light turns ON. The liquid crystal response is completed during the row scanning period, so when the back light turns ON, the image is already ready for display. This preliminary action eliminates the need to turn off the back light waiting for liquid crystal response.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution extends the back light 'ON' time, enhancing utilization efficiency and maintaining image display stability, preventing color mixing and increasing image brightness without increasing power consumption.
Implementation Method 1
each pixel unit comprising: a drive switch, a pixel electrode, a working storage element connected with the drive switch and used to hold image voltage signals
Implementation Method 2
a display refresh switch connected with the working storage element and the pixel electrode; frame refresh lines, used to input frame refresh signals including a frame refresh 'ON' signal and a frame refresh 'OFF' signal to the corresponding pixel unit so as to control the display refresh switch
Implementation Method 3
Liquid crystal is driven to be rotated by an electrical field formed between the array substrate and the color filter substrate, thus the light transmissivity is changed
Data Source
AI summary
A driving method for an array substrate of a liquid crystal display, the method comprising: performing a display refresh operation on each pixel unit on the array substrate in a row sequence so as to refresh working storage elements in each pixel unit row by row, until the working storage elements of the pixel units in all rows in one image frame is refreshed, thus image voltage signals corresponding to the pixel units in each row are inputted to the working storage elements to be held; inputting a frame refresh “ON” signal to display refresh switches of the pixel units in each row, and inputting the image voltage signals held in the working storage elements of the pixel units in each row to the pixel electrodes of the pixel units in each row as image signal voltages, so that one image frame is refreshed; after charging for pixel capacitors of the pixel units in each row has completed in each row, inputting a frame refresh “OFF” signal so as to turn off the display refresh switch, so that the working storage elements of the pixel units in each row prepare to the storage for the image voltage signals for the next frame.