Chip-Mounted Board Luminance Uniformity via Local Quality Segmentation
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Solution Overview
Problem
Luminance unevenness in display devices caused by different emission characteristics of micro light-emitting chips from various semiconductor wafers used in the production of chip-mounted boards, leading to noticeable differences in display quality, especially in large or high-definition screens.
Innovation Solution
A chip-mounted board design with a light-emitting region structured into three distinct areas: a first region with a specific luminance, a second region with a lower luminance, and a third region with a luminance intermediate between the first two, where micro light-emitting chips from different wafers are arranged in a specific ratio, controlled by formulas (1) and (2), to minimize luminance differences and enhance display uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If micro light-emitting chips from different semiconductor wafers are used in the light-emitting region, then productivity is improved by utilizing multiple wafers, but luminance uniformity deteriorates due to different emission characteristics of LEDs from different wafers
Solution Approach 1:
The light-emitting region is divided into multiple regions (first, second, and third regions) where different ratios of LEDs from different wafers are arranged. Specifically, the third region positioned between the first and second regions contains a mixed arrangement of LEDs from both wafers, creating local variation in composition to achieve gradual luminance transition and reduce visible boundaries while maintaining high productivity through multi-wafer utilization
2Manufacturing precision
If a large screen or high-definition display device is produced, then display quality is improved, but luminance unevenness worsens due to the extended light-emitting region formed by transferring and rearranging micro light-emitting chips
Solution Approach 1:
Different regions of the large light-emitting area are assigned different compositions of LEDs from different wafers. The third region specifically designed with mixed LEDs creates local luminance compensation that counteracts the cumulative luminance unevenness that would otherwise occur across the extended display area, enabling high-definition large screens while maintaining luminance uniformity
Solution Approach 2:
The light-emitting region is segmented into multiple distinct regions with different LED composition ratios. This segmentation allows independent optimization of each region's luminance characteristics, preventing the propagation of luminance unevenness across the entire large display area and enabling high manufacturing precision in the final display quality
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
The solution effectively reduces luminance unevenness by controlling the mixing ratio of micro light-emitting chips in the third region, ensuring the contrast sensitivity exceeds acceptable limits, thereby improving the uniformity and image quality of the display screen.
Implementation Method 1
micro light-emitting chips arranged in a matrix pattern in a light-emitting region
Implementation Method 2
different emission characteristics (efficiencies, current-voltage characteristics) of the LEDs
Data Source
AI summary
A chip-mounted board including: micro light-emitting chips arranged in a matrix pattern in a light-emitting region; and a conductive line electrically connected to the micro light-emitting chips, the light-emitting region including a first region having a first luminance, a second region having a second luminance lower than the first luminance, and a third region having a third luminance lower than the first luminance and higher than the second luminance, the luminances being values determined with the same magnitude of current supplied to the micro light-emitting chips, the third region being positioned between the first region and the second region and satisfying the following formulas (1) and (2):(1+k)/(1−k)≤63.895×tan(0.5°)×500/W+6.0525 (1)L2=k×L1 (2)wherein L1 represents the first luminance, L2 represents the second luminance, and W represents a width (unit: mm) of the third region.