VR Backlight Driving Method Eliminates Residual Images
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Solution Overview
Problem
Liquid crystal display assemblies in VR applications face challenges in achieving high response speed and frame rates, leading to residual images due to the existing methods of backlight control, which either require high driving capability or cause image flickering.
Innovation Solution
A driving method for a backlight with multiple rows of light sources, where each row is lit at least twice with progressively changing brightness, and the backlight is divided into regions for adaptive brightness control based on frame-to-frame brightness differences, ensuring smooth transitions without causing flickering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the backlight is lit continuously at high brightness to maintain image quality, then the display brightness is sufficient, but residual images appear due to the liquid crystal response time limitation
Solution Approach 1:
The backlight is divided into multiple rows that are lit periodically in sequence rather than continuously. Each row is lit for a specific duration and then turned off, creating a time-division multiplexing effect. This periodic lighting pattern allows the liquid crystal to complete its response cycle before the next row is activated, eliminating residual images while maintaining sufficient display brightness through the persistence of vision.
Solution Approach 2:
The backlight is segmented into multiple independent rows that can be controlled separately. By dividing the backlight into discrete segments (rows) and activating them in sequence, the system can control the timing and duration of each segment's illumination. This segmentation enables the backlight to adapt to the liquid crystal's response characteristics, preventing residual images while maintaining overall display brightness.
2Reliability
If the backlight rows are lit in sequence to eliminate residual images, then residual images are reduced, but image flickering occurs due to the sequential lighting pattern
Solution Approach 1:
The backlight rows are lit in rapid succession with minimal or no gap between consecutive rows, creating a continuous perception of illumination. By ensuring that the lighting action continues without interruption across all rows within the frame period, the system eliminates flickering while maintaining the benefits of sequential lighting for residual image reduction. The human eye perceives this rapid sequence as continuous illumination.
Solution Approach 2:
The sequential lighting of backlight rows is performed within a time period shorter than the human visual persistence threshold, creating a periodic pattern that is perceived as stable. By controlling the timing and duration of each row's illumination within the frame period, the system achieves a periodic action that eliminates both residual images and flickering.
3Use of energy by moving object
If the backlight is dimmed to reduce power consumption, then energy efficiency improves, but the display brightness becomes insufficient
Solution Approach 1:
The backlight uses periodic illumination with time-division multiplexing, where each row is lit for a specific duration and then turned off. This periodic action reduces the total illumination time compared to continuous lighting, thereby reducing power consumption. Meanwhile, the sufficient brightness is maintained during the active lighting periods and perceived continuously through visual persistence.
Solution Approach 2:
The backlight is segmented into multiple rows that are activated in sequence rather than simultaneously. This segmentation allows the system to reduce overall power consumption by lighting only one row at a time, while the cumulative effect of sequential row activation maintains sufficient display brightness throughout the frame period.
4Speed
If the liquid crystal response speed is increased to eliminate residual images, then the frame rate can be higher, but the display complexity and cost increase
Solution Approach 1:
Instead of increasing the liquid crystal response speed through complex materials or structures, the patent uses periodic backlight lighting to synchronize with the liquid crystal's natural response cycle. By controlling the backlight to activate after the liquid crystal has responded, the system eliminates residual images without requiring faster liquid crystal response, thereby avoiding increased display complexity and cost.
Solution Approach 2:
The backlight lighting timing is synchronized with the liquid crystal response characteristics, creating a feedback-like relationship where the backlight activation is timed based on the liquid crystal's response cycle. This synchronization allows the system to work with the liquid crystal's natural response speed rather than forcing it to be faster, avoiding increased complexity.
Data Source
AI summary
The preset disclosure provides a driving method of a backlight, a backlight driving device, a backlight, a display assembly and a virtual reality apparatus. The backlight includes multiple rows of light sources arranged in an array. The driving method includes: after a preset time has elapsed from receipt of a synchronous display signal for each frame of image, lighting the light sources row by row, wherein each row of light sources is successively lit at least twice.