Two-Dimensional Local Dimming for LCD Power Reduction
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Solution Overview
Problem
Liquid crystal display devices face challenges in reducing power consumption, particularly in local dimming systems where one-dimensional and direct-illumination type backlights are inefficient, leading to higher power consumption.
Innovation Solution
A liquid crystal display device employing a two-dimensional local dimming method with an edge-illumination type backlight, where light sources are strategically positioned to emit block lights to specific sub-frames and row/column blocks, with brightness determined by light source data, allowing adaptive dimming and reduced power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If one-dimensional local dimming or direct-illumination type backlight is used, then the backlight can provide uniform illumination, but power consumption increases
Solution Approach 1:
The backlight is divided into multiple independent light source groups arranged in a matrix configuration, where each group can be independently controlled to illuminate specific pixel blocks. This segmentation allows only the necessary light sources to be activated based on the display content, reducing overall power consumption while maintaining illumination uniformity where needed.
Solution Approach 2:
Different regions of the display panel receive different illumination levels according to the local brightness requirements of the pixel blocks. The light source brightness data is determined based on the maximum brightness values of corresponding pixel blocks, enabling adaptive local dimming that reduces power consumption in dark regions while maintaining brightness in luminous regions.
2Use of energy by moving object
If direct-illumination type backlight is used, then illumination coverage is improved, but the number of light sources increases leading to higher power consumption
Solution Approach 1:
The patent transitions from one-dimensional light source arrangement to a two-dimensional matrix arrangement of light sources. This dimensional change allows for more efficient spatial utilization of light sources, where each light source group can cover a specific pixel block area, reducing the total number of light sources needed while maintaining comprehensive illumination coverage.
Data Source
AI summary
According to some embodiments of the inventive concept, there is provided a liquid crystal display device including a backlight including a light source configured to emit first to N-th block lights respectively to first to N-th sub-frames, in a first direction, the first to N-th sub-frames being obtained by dividing a frame in time, and a display panel including pixels arranged in a matrix form and grouped into first to N-th row blocks along the first direction, the pixels being configured to display an image using the first to N-th block lights, and operations of the first to N-th row blocks being respectively synchronized with the first to N-th sub-frames, wherein a brightness of a K-th block light among the first to N-th block lights is determined on a basis of light source brightness data of a K-th row block among the first to N-th row blocks.