LED Pixel Device Chip Stack Structure
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Solution Overview
Problem
Current LED display technologies face challenges in chip bonding due to the small size and high number of red, green, and blue LED chips, leading to low yield and increased defects, particularly with the PKG-on-module technology, which also struggles with reducing pixel or sub-pixel size and distance between sub-pixels.
Innovation Solution
An LED pixel device with a chip stack structure where light-emitting cells of different wavelengths are stacked into an integrated chip, with each cell located in distinct regions and heights on separate light-transmitting substrates, allowing for emission of different wavelengths through different areas of the upper surface, utilizing gallium nitride and gallium arsenide epilayers for blue, green, and red light emission respectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple small R, G, and B chips are bonded together to produce full-color LED displays, then the display can achieve full-color emission, but the chip bonding process becomes very difficult and yield decreases
Solution Approach 1:
The patent merges multiple LED chips (R, G, and B chips) into a single integrated LED chip structure. The first, second, and third LED chips are bonded together in an integrated manner, eliminating the need to bond numerous separate chips. This merging approach maintains full-color emission capability while significantly improving manufacturing yield by reducing the complexity of the bonding process.
Solution Approach 2:
The patent employs a nested structure where multiple LED chips are stacked vertically within a single integrated chip footprint. The first LED chip is positioned at a first height, the second LED chip at a second height, and the third LED chip at a third height, creating a three-dimensional nested arrangement. This nesting approach reduces the horizontal space required and simplifies the bonding process compared to planar arrangements.
2Device complexity
If PKG-on-module technology is used to produce RGB light, then integration is achieved, but additional packaging processes are required and chips are likely to be tilted during packaging, increasing defects
Solution Approach 1:
The patent combines the LED chip integration and packaging functions into a single integrated LED chip structure. By bonding multiple LED chips together before final module assembly, the invention eliminates the need for separate packaging processes that cause chip tilting and defects. The integrated structure is directly mounted onto the module, simplifying the manufacturing process.
Solution Approach 2:
The patent performs the chip bonding and integration process before the final module assembly, creating a pre-integrated LED chip unit. This preliminary integration action allows the chips to be securely bonded in their correct positions before mounting, preventing tilting and defects that would occur during subsequent packaging operations.
3Ease of operation
If traditional LED chip arrangements are used, then sub-pixels can be formed, but the size of pixels or sub-pixels cannot be reduced and distances between sub-pixels are large
Solution Approach 1:
The patent transitions from a two-dimensional planar arrangement of LED chips to a three-dimensional stacked configuration. By positioning LED chips at different heights (first height, second height, third height) within a vertical stack, the invention充分利用 the third dimension to reduce the horizontal footprint of each pixel. This dimensional change enables significant pixel size reduction while maintaining adequate spacing for light emission.
Solution Approach 2:
The patent nests multiple LED chips vertically within a compact three-dimensional structure, allowing sub-pixels to be arranged in a space-efficient manner. The nested vertical arrangement reduces the horizontal distance between sub-pixels compared to traditional planar layouts, enabling higher pixel density and smaller pixel sizes.
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 solution enables efficient emission of light beams of different wavelengths through distinct areas of the chip surface, improving yield and reducing defects by integrating multiple LED chips into a single structure, thus overcoming the limitations of existing technologies in size reduction and sub-pixel spacing.
Implementation Method 1
a first light-emitting cell underlying the first light-transmitting substrate, a second light-emitting cell interposed between the first light-transmitting substrate and the second light-transmitting substrate, and a third light-emitting cell interposed between the second light-transmitting substrate and the third light-transmitting substrate wherein the first light-emitting cell, the second light-emitting cell, and the third light-emitting cell emit light of different wavelengths
Data Source
AI summary
An LED pixel device is disclosed. The LED pixel device includes a first light-transmitting substrate, a second light-transmitting substrate overlying the first light-transmitting substrate, a third light-transmitting substrate overlying the second light-transmitting substrate, a first light-emitting cell underlying the first light-transmitting substrate, a second light-emitting cell interposed between the first light-transmitting substrate and the second light-transmitting substrate, and a third light-emitting cell interposed between the second light-transmitting substrate and the third light-transmitting substrate. The first light-emitting cell, the second light-emitting cell, and the third light-emitting cell emit light of different wavelengths.