Backlight Unit With Gradually Increasing Light Source Spacing
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Solution Overview
Problem
LED backlight units for large-size LCD devices face issues with abrupt light efficiency variations due to heat, leading to color balance collapse and increased manufacturing costs due to the large number of LEDs required.
Innovation Solution
A backlight unit design with a bottom cover featuring light source groups where the spacing between adjacent groups increases gradually from the central portion to the edges, reducing the number of light sources and heat generation, allowing for low-current driving and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a large number of LEDs are used in large-size LCD backlight units, then the luminance coverage is improved, but the heat generation increases and color balance stability deteriorates
Solution Approach 1:
The patent divides the backlight unit into multiple light source groups arranged in specific patterns (e.g., alternating odd and even groups, or groups at different heights). This segmentation allows better heat distribution and reduces the concentration of heat in one area, thereby improving color balance stability while maintaining adequate luminance coverage across the display area.
Solution Approach 2:
The patent employs different driving currents for different light source groups based on their positions. Central light source groups receive higher driving currents to compensate for the distance from edges, while edge groups receive lower currents. This local quality adjustment ensures uniform luminance distribution and prevents color balance issues caused by uniform high-current driving of all LEDs.
2Illumination intensity
If a large number of LEDs are used in large-size LCD backlight units, then the luminance coverage is improved, but the manufacturing cost increases
Solution Approach 1:
The patent uses a reduced number of light source groups compared to conventional designs, activating only necessary LED groups based on display size and luminance requirements. By calculating and implementing the minimum required number of light source groups (e.g., using fewer groups for smaller displays), the patent reduces manufacturing costs while maintaining adequate luminance coverage through optimized current distribution and reflective structures.
3Ease of manufacture
If the spacing between light source groups is uniform, then the manufacturing simplicity is improved, but the luminance uniformity deteriorates
Solution Approach 1:
The patent implements asymmetric spacing between light source groups, where the spacing varies depending on the position (e.g., smaller spacing near edges, larger spacing in the center). This asymmetric arrangement compensates for the geometric distribution of light and reflective surfaces, achieving uniform luminance across the display area while maintaining reasonable manufacturing simplicity through standardized group structures.
Data Source
AI summary
A backlight unit capable of preventing a degradation in luminance, while achieving a reduction in heat generation and a reduction in manufacturing costs by adjusting the arrangement of the light sources while reducing the number of the light sources is disclosed. The disclosed backlight unit includes a bottom cover formed with a plurality of light source groups each including a plurality of light sources arranged in one direction. The spacing of the adjacent light source groups increases gradually from a central portion of the bottom cover to opposite edges of the bottom cover.