Stacked LED Sub-Pixels with Conductive Adhesive Layers
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Solution Overview
Problem
LED displays face challenges in reducing the size of LED chips while maintaining luminous area and efficiency, leading to increased manufacturing time and complexity due to the need for precise mounting of multiple sub-pixels in a restricted area.
Innovation Solution
A light emitting device comprising multiple stacked LED sub-units with conductive adhesive layers for electrical connection, allowing for reduced chip size and increased luminous area, and a protection layer for handling and packaging, enabling efficient color mixing and simplified manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If individual LED chips are arranged in each sub-pixel on a two-dimensional plane, then color display capability is achieved, but the number of LED chips increases and mounting time increases
Solution Approach 1:
The patent transitions from a two-dimensional arrangement of LED chips to a three-dimensional stacked structure. Multiple LED chips are vertically stacked and bonded together, utilizing the third dimension (height) to accommodate multiple light-emitting elements within the same planar footprint. This dimensional transition allows multiple sub-pixels to be integrated in a compact volume without increasing the mounting area or time significantly.
Solution Approach 2:
The patent combines multiple LED chips into a single stacked assembly that functions as an integrated unit. The LED chips are bonded together with adhesive layers and electrically connected through conductive structures, merging them into a compact module that occupies less space and simplifies the mounting process compared to arranging individual chips separately.
2Area of stationary object
If LED chip size is reduced to fit more sub-pixels in restricted area, then pixel density increases, but mounting difficulty increases and luminous area decreases
Solution Approach 1:
Multiple small LED chips are merged into a stacked assembly where they are bonded together with adhesive layers. This consolidation creates a single manageable unit that is easier to handle and mount than individual microscopic chips, reducing mounting difficulty while maintaining high pixel density.
Solution Approach 2:
The LED chips are nested vertically in a stacked configuration, with each chip positioned above the other along the vertical axis. This nesting arrangement maximizes the use of vertical space within the restricted pixel area, achieving high pixel density without requiring extremely small individual chip sizes.
3Area of stationary object
If LED chip size is reduced to fit more sub-pixels, then area per pixel decreases, but luminous area of each chip decreases further
Solution Approach 1:
The patent compensates for the reduced planar area of each LED chip by utilizing the vertical dimension. Multiple chips are stacked vertically, allowing each chip to maintain adequate luminous area while the overall pixel footprint is minimized through the stacked configuration.
Solution Approach 2:
The light-emitting function of each pixel is segmented across multiple LED chips stacked vertically. Instead of relying on a single large chip, the total luminous output is distributed across several smaller chips arranged in stack, maintaining adequate luminous area per chip while achieving compact pixel 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
The solution allows for a larger effective area per sub-pixel within a restricted space, reducing manufacturing time and complexity, while maintaining or improving luminous efficiency and color mixing ratios.
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 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, 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, in which the second light emitting stack is disposed between the first light emitting stack and the third light emitting stack, and one of the first adhesive layer and the second adhesive layer electrically connects adjacent light emitting stacks.