Display Driver Preparatory Write for Liquid Crystal Response Time
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Solution Overview
Problem
Liquid crystal display devices face challenges in achieving high response characteristics, particularly in applications like Virtual Reality and Augmented Reality, where they lag behind self-luminous devices like OLEDs due to their light shutter operation principle, and methods like overdrive and backlight control have limitations in uniform voltage adjustment and visibility improvement.
Innovation Solution
A display driver system that employs a preparatory write operation, where a predetermined gradation voltage is written to liquid crystal pixels before the main image signal, allowing the liquid crystals to respond fully before the backlight is turned on, thereby improving response time and visibility without increasing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If overdrive method is used to improve response time, then response characteristics are improved, but uniform voltage adjustment across pixels becomes difficult
Solution Approach 1:
The patent applies preliminary action by writing a preparatory voltage to pixels before the actual image signal. This preparatory voltage is written in advance to ensure that liquid crystal molecules are ready to respond quickly when the backlight turns on, thereby improving response time without compromising voltage uniformity across the display panel.
2Speed
If backlight lighting time is shortened to improve visibility, then response characteristics are improved, but pixels written in the latter half may show visible response operations
Solution Approach 1:
The patent writes a preparatory voltage to pixels before the backlight turns on, ensuring that liquid crystal molecules are already in their target state when illumination begins. This eliminates visible response operations during backlight illumination while maintaining short effective response time and consistent display visibility across all pixels.
3Speed
If liquid crystal response time is reduced for VR/AR applications, then display performance is improved, but the light shutter operation principle limits achievable speed
Solution Approach 1:
The patent applies preliminary action by pre-writing voltages to liquid crystal pixels before backlight illumination. This allows the liquid crystal molecules to complete their reorientation in advance, achieving effectively zero visible response time during the display period. This resolves the speed limitation inherent in liquid crystal's physical reorientation mechanism while maintaining high display performance for VR/AR applications.
Data Source
AI summary
According to one embodiment, a display driver configured to control a display operation of an active-matrix display device, wherein the display device includes a display area in which liquid crystal pixels are arranged in a matrix form, a plurality of scanning lines arranged along rows, a plurality of signal lines arranged along columns, a plurality of switching elements arranged in the vicinities of positions at which the scanning lines and the signal lines intersect each other, and a backlight, and the display driver controls preparatory write of writing a signal of a predetermined gradation to the liquid crystal pixels, thereafter controls sequential write of an image signal to the liquid crystal pixels, and at the time after an elapse of a predetermined time from the preparatory write, makes the backlight light up.