LED Device with Patterned Substrate Protrusions
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Solution Overview
Problem
Existing light emitting devices face challenges in achieving high luminance due to limited light extraction efficiency, particularly in structures where the sidewall of light emitting regions are inclined, leading to potential disconnection of connection metals and reduced light emitting area.
Innovation Solution
The light emitting device incorporates a substrate with an uneven patterned portion, such as a patterned sapphire substrate, and a buffer layer to reduce lattice constant differences, along with conductive layers and electrodes to increase the area of light emitting regions, enhancing light extraction efficiency and preventing electrical short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sidewall of light emitting regions is inclined to prevent disconnection of connection metals, then reliability is improved, but the light emitting area is reduced
Solution Approach 1:
The patent introduces a vertical dimension by forming a protrusion on the substrate surface. The light emitting region is positioned on this protrusion, effectively utilizing three-dimensional space rather than relying solely on horizontal expansion. This dimensional change allows the light emitting area to be increased without requiring larger lateral dimensions that would conflict with the inclined sidewall structure.
Solution Approach 2:
The substrate surface is pre-formed with an uneven pattern creating protrusions before the light emitting regions are fabricated. This preliminary action of creating the protrusion structure provides a foundation that increases the available area for light emitting regions while maintaining the inclined sidewall configuration for connection metal stability.
2Productivity
If the area of light emitting regions is increased to improve luminous efficacy, then luminous intensity is improved, but current density increases leading to potential reliability issues
Solution Approach 1:
By positioning light emitting regions on vertically protruding structures, the patent increases the effective light emitting area without proportionally increasing the current load on any single region. The three-dimensional configuration distributes current more effectively across multiple regions while maintaining high total luminous output.
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 increases the total light emitting area, leading to improved luminous intensity and reduced current density, thereby enhancing the reliability and efficiency of the light emitting device.
Implementation Method 1
a buffer layer to reduce lattice constant differences
Data Source
Figure 1
Figure 2
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AI summary
A light emitting device is disclosed. The light emitting device includes a substrate, a plurality of light emitting cells disposed on the substrate to be spaced apart from each other, and a connection wire electrically connecting adjacent ones of the light emitting cells, wherein one of the adjacent light emitting cells includes a plurality of first segments, and the other of the adjacent light emitting cells includes a plurality of second segments respectively facing the first segments, wherein a separation distance between first and second segments facing each other, each of which has an end contacting the connection wire is greater than a separation distance between first and second segments facing each other, each of which has an end that does not contact the connection wire.