Stacked RGB Light Emitters With Conductive Adhesive Interconnects
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Solution Overview
Problem
LED displays face challenges in reducing the size of LED chips while maintaining luminous areas and efficiency, leading to increased manufacturing time and complexity due to the arrangement of sub-pixels on a two-dimensional plane.
Innovation Solution
A light emitting device comprising multiple stacked LED sub-units with conductive adhesive layers connecting them, allowing for reduced chip size and increased luminous area, with indium tin oxide (ITO) used for electrical connection, and a protection layer for handling and packaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If one LED chip is arranged in each sub-pixel on a two-dimensional plane, then the display apparatus can show various colors, but the number of LED chips increases excessively, requiring excessive time for the mounting process
Solution Approach 1:
The patent transitions from a two-dimensional arrangement of LED chips to a three-dimensional stacked structure. Multiple LED chips emitting different colors (blue, green, red) are vertically stacked and bonded together, allowing color display while reducing the number of individual mounting operations. The stacked configuration enables multiple chips to be integrated into a single pixel unit, significantly reducing mounting complexity and time.
Solution Approach 2:
The patent merges multiple LED chips into a single integrated stacked structure. Instead of mounting separate LED chips for each sub-pixel, the invention combines blue, green, and red LED chips into a vertically stacked assembly that functions as a unified light-emitting unit. This merging reduces the total number of mounting operations and simplifies the manufacturing process.
2Area of stationary object
If the area of each LED chip is reduced to arrange sub-pixels in a restricted area, then more sub-pixels can fit in the display, but it causes difficulty in mounting LED chips and reduces luminous areas
Solution Approach 1:
The patent resolves the area constraint by moving from two-dimensional chip arrangement to three-dimensional stacking. Multiple LED chips are arranged vertically rather than horizontally, allowing the display to achieve high pixel density without reducing individual chip sizes. This vertical integration maintains adequate chip dimensions for easy mounting while maximizing the number of pixels that can be displayed in a given area.
3Ease of manufacture
If conventional adhesive layers are used to bond LED chips, then the bonding process is simple, but electrical connection between adjacent light emitting stacks is not achieved
Solution Approach 1:
The patent employs adhesive layers that perform dual functions: mechanical bonding and electrical conduction. The conductive adhesive material simultaneously bonds adjacent LED stacks together and provides electrical pathways between them, eliminating the need for separate bonding and wiring steps. This multi-functional approach maintains manufacturing simplicity while ensuring reliable electrical connections.
Solution Approach 2:
The conductive adhesive layer acts as an intermediary between adjacent LED stacks, providing both mechanical support and electrical connectivity. This intermediate material bridges the gap between chips, enabling both structural integrity and electrical signal transmission without requiring complex interconnection structures.
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 enhances the integration of colors in a smaller area, simplifies the manufacturing process, and improves the handling and packaging of micro-LEDs, while maintaining or improving luminous efficiency.
Implementation Method 1
one of the first adhesive layer and the second adhesive layer electrically connects adjacent light emitting stacks
Implementation Method 2
a first light emitting stack, a second light emitting stack, and a third light emitting stack each including a first conductivity type semiconductor layer and a second conductivity type semiconductor layer
Implementation Method 3
The first, second, and third light emitting stacks may be configured to emit red light, blue light, and green light, respectively
Implementation Method 4
a first adhesive layer bonding the first light emitting stack and the second light emitting stack, and a second adhesive layer bonding the second light emitting stack and the third light emitting stack
Data Source
AI summary
A light emitting device including a first light emitter, a second light emitter, and a third light emitter, each including a first conductivity type semiconductor layer and a second conductivity type semiconductor layer. An adhesive layer includes a first adhesive portion disposed between the first light emitter, and the second light emitter, and a second adhesive portion disposed between the second light emitter and the third light emitter, in which the second light emitter is disposed between the first light emitter and the third light emitter, and the first adhesive portion and the second adhesive portion are optically transmitting and connect adjacent light emitters.