LCD Backlight LED Matrix Segmentation for Brightness Control
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Solution Overview
Problem
Liquid crystal display devices with large size screens using direct-lit backlights face challenges in reducing thickness without increasing the number of LEDs, leading to higher power consumption, while edge-lit backlights require more LEDs to achieve comparable brightness, resulting in increased power consumption and manufacturing costs.
Innovation Solution
A liquid crystal display device with a backlight featuring a rectangular light guide plate divided into matrix-form blocks, where the number of LEDs and block sizes are adjusted to optimize light intensity and distribution, with more LEDs and larger blocks in central areas and fewer LEDs and smaller blocks in peripheral areas, reducing overall LED count and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If direct-lit backlight with LEDs is used to increase screen brightness, then brightness is improved, but thickness cannot be reduced
Solution Approach 1:
The light guide plate is divided into multiple blocks arranged in a matrix pattern, with different numbers of LEDs assigned to different blocks. This segmentation allows selective lighting of specific areas, enabling brightness control while reducing overall LED count and thickness requirements compared to uniform direct-lit configurations.
Solution Approach 2:
Different regions of the light guide plate are assigned different densities of LEDs. Central areas have higher LED density for brighter display, while peripheral areas have lower density. This local variation optimizes brightness where needed without uniformly increasing LED count across the entire backlight, thereby reducing overall thickness and power consumption.
2Length of stationary object
If edge-lit backlight is used to reduce thickness, then thickness is reduced, but more LEDs are required achieving comparable brightness
Solution Approach 1:
The light guide plate is segmented into multiple blocks that can be independently controlled. This allows the system to function as an edge-lit backlight with reduced thickness while using fewer LEDs overall, since not all blocks need to be illuminated at full intensity simultaneously.
Solution Approach 2:
Instead of requiring LEDs across the entire edge to achieve uniform brightness, the invention uses partial illumination of specific light guide blocks. By assigning different numbers of LEDs to different blocks and controlling them selectively, the system achieves comparable brightness with fewer total LEDs than traditional edge-lit designs.
3Ease of manufacture
If uniform LED density is used across the light guide plate, then manufacturing is simplified, but brightness nonuniformity occurs
Solution Approach 1:
The invention deliberately creates non-uniform LED density distribution across the light guide plate, with higher density in central blocks and lower density in peripheral blocks. This local variation compensates for the natural light distribution characteristics of light guide plates, achieving uniform brightness across the display screen while maintaining manageable manufacturing complexity through modular block design.
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 configuration allows for a thinner backlight with reduced power consumption without compromising screen brightness, achieved through area control for brightness and efficient LED placement, facilitating cost reduction and improved contrast.
Implementation Method 1
Each of the light guide plate blocks receives light emitted from a corresponding light source of the light sources, and redirects the light toward the liquid crystal display panel
Data Source
AI summary
An LCD device using LEDs as light sources provided herein is capable of reducing the manufacturing cost and the power consumption by a reduction in the number of LEDs used. A backlight according to the present invention includes LEDs mounted on a wiring board and a light guide plate having a matrix array of light guide plate blocks assigned the LEDs. The number of LEDs assigned to the block located in a peripheral area is smaller than the number assigned to the block located around the center to reduce the number of LEDs used in the backlight. If a ratio of the brightness in a peripheral area of the screen to the brightness in a central area is 60% or higher, the human eye does not perceive non-uniform luminance. Thus, the manufacturing cost and the power consumption of the LCD device can be reduced.