LED Array Longitudinal Pitch Consistency via Angled Chip Ends
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Solution Overview
Problem
Existing LED arrays face challenges in maintaining uniform irradiance and high density when multiple chips are abutted to form longer arrays, leading to discontinuities and reduced emitter density, which limits their application in high-speed printing and other applications.
Innovation Solution
The solution involves arranging LEDs on a substrate in a plurality of rows with longitudinal offset and consistent pitch, allowing for the fabrication of LED chips with angled end faces to maintain pitch consistency when adjacent chips are positioned together, enabling the formation of continuous arrays without gaps and enhancing packaging efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If multiple LED chips are abutted to form longer arrays, then the array length is increased, but the emitter density and uniformity deteriorate due to spacing gaps between chips
Solution Approach 1:
The LED array is segmented into multiple individual LED chips that can be manufactured separately and then assembled together. Each chip contains a subset of the total LED emitters, allowing modular construction of longer arrays while maintaining consistent emitter spacing through precise positioning features on each chip segment.
2Length of moving object
If multiple LED chips are abutted to form longer arrays, then the array length is increased, but the illumination uniformity deteriorates due to discontinuities at chip boundaries
Solution Approach 1:
The LED chips are designed with asymmetric positioning features, specifically an angled end face on one chip that complements a corresponding angle on the adjacent chip. This asymmetric geometry ensures precise alignment and eliminates gaps or discontinuities at the boundaries where chips are abutted, maintaining uniform illumination across the entire array length.
3Ease of manufacture
If traditional LED chip packaging is used, then manufacturing is simpler, but the pitch consistency between LEDs across multiple chips deteriorates
Solution Approach 1:
The precise pitch consistency is built into the chip design itself through preliminary geometric features (angled end faces) during manufacturing. This preliminary action embeds the alignment information directly in the chip structure, so that during assembly, the chips naturally self-align to maintain consistent LED pitch across the entire array without requiring complex post-assembly adjustment mechanisms.
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 approach allows for continuous, uniform illumination with increased emitter density and resolution, overcoming the limitations of traditional LED arrays by maintaining consistent pitch between LEDs across multiple chips, thus improving the yield and cost-effectiveness of LED array production.
Implementation Method 1
LEDs are a form of semiconductor material that convert electrical energy into optical energy. In semiconductor LEDs, light is typically generated through recombination of electrons, originating from an n-type doped semiconductor layer, and holes originating from a p-type doped semiconductor layer.
Implementation Method 2
At least part of an end face of the substrate is angled with respect to a transverse axis of the LED chip such that the LED chip is positionable adjacent another LED chip to maintain the longitudinal pitch between adjacent LEDs on different chips.
Data Source
Figure 1a~1b
Figure 2
Figure 3a~3b
AI summary
A display, comprising a light emitting diode (LED) chip (10, 20, 30), including a substrate (12, 22, 32); and an array of LEDs on the substrate arranged in a plurality of rows along a longitudinal direction (38a) of the substrate, LEDs in a row of the array being longitudinally offset from corresponding LEDs in another row, and adjacent LEDs in each row of the array being separated by the same longitudinal pitch (36a), each of the LEDs having a diameter between 1 µm and 50 µm.