Vertical LED Chip Layout With Diagonal Current and Edge Pad
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional small-sized vertical light emitting diode (LED) chips have low energy efficiency due to light shielding and poor heat dissipation, and their reliability is compromised by micro-cracks and defects caused by wire bonding, especially in automotive applications where high reliability is demanded.
Innovation Solution
A small-sized vertical LED chip design featuring a P-type electrode, chip conductive base structure, interface structure with a highly conductive and reflective metal layer, PN junction structure, insulating layer, bridging connected metal layer, N-type ohmic contact electrode, and N-type electrode pad, where the current is conducted diagonally to avoid shielding and light-absorbing substances, and the N-type electrode pad is not directly wired on the PN junction structure to prevent defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the N-type electrode pad is provided in a central region on the N-type semiconductor to conduct current, then the current conduction is improved, but the central light emission is shielded and wire bonding causes micro-cracks and defects
Solution Approach 1:
The patent moves the N-type electrode pad from a planar position above the active layer to a lateral position at the edge of the chip, utilizing the third dimension (lateral vs. vertical positioning) to resolve the conflict between current conduction and light emission. This dimensional repositioning allows the electrode pad to conduct current effectively while being positioned outside the light emission path, eliminating both light shielding and wire bonding defects.
Solution Approach 2:
The patent extracts the N-type electrode pad from its traditional position above the active layer and relocates it to the lateral edge of the chip. This extraction removes the harmful interaction between the electrode pad and the light emission region, allowing the light emitting surface to be completely free of shielding substances while maintaining effective current conduction through the relocated electrode pad.
2Productivity
If the chip size is reduced to achieve small-sized LED displays, then the display density is improved, but the electrode pads become too small and close together causing short-circuits
Solution Approach 1:
The patent utilizes lateral positioning of the N-type electrode pad at the chip edge, moving the electrode connection to a different spatial dimension (lateral vs. vertical). This dimensional change allows the electrode pad to be positioned far from the P-type electrode in the lateral direction, maintaining adequate spacing and preventing short-circuits even when the chip size is reduced for high-density displays.
3Volume of moving object
If the electrode pad area is reduced to achieve smaller chip size, then the chip dimensions are improved, but the heat dissipation performance deteriorates
Solution Approach 1:
The patent positions the N-type electrode pad laterally at the chip edge rather than vertically above the active layer. This dimensional repositioning allows the electrode pad to maintain a sufficient area for heat dissipation while the chip overall size is reduced. The lateral placement provides access to the chip perimeter, enabling effective thermal management without compromising the compact chip dimensions.
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 design enhances energy efficiency by eliminating light shielding and improving heat dissipation, while ensuring high reliability by reducing the risk of micro-cracks and defects during the wire bonding process, making it suitable for high-contrast automotive displays.
Implementation Method 1
a lower reflecting surface... free of shielding and light-absorbing substances
Implementation Method 2
PN junction structure 5 comprises a P-type semiconductor 5A, an active layer 5B and an N-type semiconductor 5C
Implementation Method 3
light emitting diodes (LED)... light-emitting efficiency
Implementation Method 4
the heat dissipation of the electrode pad of the small-sized chip is worse than that of the vertical LED, wherein the electrode pad of the vertical LED is on the whole surface of the bottom
Data Source
AI summary
The invention is a small-sized vertical light emitting diode chip with high energy efficiency, wherein a PN junction structure is arranged on a light-emitting region platform of an interface structure; a highly reflective metal layer is arranged under the light-emitting region platform; the interface structure is provided with a P-type ohmic contact area under an outwardly extending platform adjacent to the light-emitting region platform; an insulating layer is formed on the outwardly extending platform; an N-type ohmic contact electrode is in ohmic contact with the PN junction structure and covers the border covering region at a position opposite to the outwardly extending platform; the current conduction is achieved diagonally on the opposite sides by locally diagonally symmetric geometric positioning of the N-type ohmic contact electrode and the P-type ohmic contact area.