LCD Row-Group Driving With Pre-Charge for Flicker Control
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Solution Overview
Problem
Existing liquid crystal display technologies face issues with image quality degradation due to flicker and luminance deviation, particularly in high-resolution and high-speed applications such as small head-mounted displays and VR devices, which are exacerbated by capacitive coupling between adjacent pixels during image signal writing.
Innovation Solution
A driving method that includes a pre-charge period to uniformly set pixel potentials, followed by a gate-grouping approach where adjacent rows are driven simultaneously, reducing capacitive coupling effects and ensuring accurate gradation across pixels, combined with a backlight control mechanism to enhance image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional driving method is used to drive liquid crystal displays, then the display can operate, but image quality degrades due to flicker and luminance deviation
Solution Approach 1:
The patent applies preliminary action by introducing a pre-charge period before the main image signal writing period. During this pre-charge period, all pixels are simultaneously charged to a predetermined potential, preparing them in advance for the subsequent image signal writing. This preliminary charging action ensures that all pixels start from the same potential state, preventing potential differences that cause luminance deviation and flicker during the image display period.
2Measurement precision
If high-resolution and high-speed display is implemented, then display performance improves, but capacitive coupling between adjacent pixels causes gradation differences
Solution Approach 1:
The patent applies segmentation by dividing the pixel array into multiple row groups, where each row group consists of multiple rows that are driven simultaneously. This segmentation allows the display to process and write image signals to different row groups in sequence rather than all pixels simultaneously, reducing the capacitive coupling effects between adjacent pixels while maintaining high resolution and speed performance.
3Reliability
If a pre-charge period is added to uniformly set pixel potentials, then capacitive coupling effects are reduced, but the frame period increases
Solution Approach 1:
The patent applies periodic action by implementing a cyclic driving sequence that includes the pre-charge period followed by multiple sub-frames for image signal writing. This periodic structure ensures that all pixels are uniformly charged before each image display cycle, maintaining gradation uniformity while the overall frame period remains manageable through efficient timing control and sequential processing of row groups.
Data Source
AI summary
A display device includes a backlight unit, a plurality of pixels, a gate-line driver circuit, a signal-line driver circuit, and a control substrate. The plurality of pixels is so that light from the light-emitting element is incident and is arranged in a matrix form with a plurality of row and a plurality of columns. The control substrate is electrically connected to the backlight unit, the gate-line driver circuit, and the signal-line driver circuit. The plurality of rows is composed of a plurality of row groups having the same number of rows and sequentially arranged in a column direction. The control substrate is configured to, in a first frame period, to supply the same potential to all of the plurality of pixels to supply the gate-line driver circuit and the signal-line driver circuit with a control signal for performing a pre-charge.