LED Rank Layout for Uniform LCD Backlight Brightness
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Solution Overview
Problem
Existing liquid crystal displays (LCDs) face issues with brightness degradation due to non-uniform distribution of light-emitting devices (LEDs) with varying characteristics, leading to stains on the backlight unit (BLU) when devices with the same rank are mounted at overlapping mounting points.
Innovation Solution
A method and device for determining the ranks of LEDs on a substrate using a block group-based random rank pattern, ensuring even distribution by calculating block group types and mounting points per rank, and allocating ranks to minimize redundant arrangements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If light-emitting devices are mounted on substrate without rank consideration, then manufacturing process is simple, but brightness uniformity deteriorates causing stains
Solution Approach 1:
The patent applies preliminary action by determining the ranks of light-emitting devices before mounting them on the substrate. The control device calculates rank values based on luminous flux measurements and pre-arranges mounting positions according to rank patterns, ensuring that devices of the same rank are properly distributed before the actual mounting process begins. This prevents brightness non-uniformity from the outset while maintaining manufacturing efficiency.
Solution Approach 2:
The patent implements local quality by assigning different rank patterns to different regions of the substrate. The control device divides the substrate into multiple regions and applies specific rank distribution patterns to each region based on the characteristics of light-emitting devices allocated to that region. This ensures optimal brightness uniformity in each local area while considering the overall distribution across the entire substrate.
2Ease of operation
If light-emitting devices of same rank overlap on substrate, then mounting is straightforward, but brightness degradation occurs causing stains
Solution Approach 1:
The patent applies parameter changes by using rank values as a key parameter to control the mounting arrangement. The control device calculates rank values based on luminous flux measurements and uses these parameters to determine mounting positions. By changing the arrangement parameter from simple sequential mounting to rank-based positional assignment, the system prevents same-rank device overlap while maintaining operational simplicity through automated control.
Solution Approach 2:
The patent implements feedback by measuring the luminous flux of each light-emitting device, calculating its rank value, and using this information to determine the appropriate mounting position. The control device receives luminous flux data, processes it to determine ranks, and then assigns mounting positions accordingly. This closed-loop feedback mechanism ensures that devices are mounted in positions that prevent brightness degradation while maintaining ease of operation through automated decision-making.
Data Source
AI summary
Provided is a method of determining ranks of a light-emitting devices each mounted at a plurality of respective mounting points on a substrate. The method of determining ranks of light-emitting devices each mounted at a plurality of respective mounting points on a substrate includes obtaining a size of a block including at least one mounting point, and obtaining a number of rank types, determining a number of block group types and a number of mounting points per rank included in an individual block group, determining, by using the number of block group types, arrangements of a plurality of block groups at the plurality of mounting points, and determining the ranks of the light-emitting devices each mounted at the plurality of respective mounting points based on the arrangements of the plurality of block groups and the number of mounting points per rank.