Stacked LED Sub-Units for Compact Pixels and Uniform Color Viewing
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Solution Overview
Problem
LED display apparatuses face challenges in reducing the area occupied by sub-pixels, increasing manufacturing time, achieving uniform RGB mixing ratios, and minimizing viewing angles of different colors, which affect image quality and brightness.
Innovation Solution
The display apparatus includes a substrate with multiple light-emitting devices, each comprising a stack of LED sub-units emitting red, blue, and green light, with a molding layer covering the sides and exposing the top surfaces, allowing for reduced pixel area, faster mounting, and unified viewing angles by adjusting the luminance intensity ratios and light emission characteristics.
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 various colors can be displayed, but the number of LED chips increases and mounting process time becomes excessive
Solution Approach 1:
The patent transitions from a two-dimensional arrangement of LED chips to a three-dimensional stacked structure where multiple LED chips are vertically arranged. This vertical stacking reduces the number of chips per pixel while maintaining full-color display capability, thereby reducing mounting complexity and process time.
Solution Approach 2:
The patent combines multiple LED chips (red, green, blue) into a single integrated light-emitting unit with a unified housing and lens structure. This merging allows the chips to be mounted together as one assembly rather than individually, significantly reducing mounting process time while maintaining color display versatility.
2Adaptability or versatility
If sub-pixels are arranged on a two-dimensional plane, then various colors can be displayed, but a relatively large area is occupied by one pixel and luminous area is reduced when area is restricted
Solution Approach 1:
The patent employs a three-dimensional stacked arrangement of LED chips vertically within each pixel, transitioning from two-dimensional lateral arrangement to vertical stacking. This enables multiple color-emitting chips to occupy the same footprint area, significantly reducing the overall pixel area while maintaining full-color display capability and increasing luminous area within restricted space.
3Ease of operation
If viewing angles of blue, green, and red light emitted within one pixel are large, then light can be seen from wider angles, but interference of light between adjacent pixels occurs and clear image quality is difficult to realize
Solution Approach 1:
The patent applies different properties to different parts of the light emission system: the housing and lens are designed with specific optical characteristics to control and narrow the viewing angles of emitted light. This local optimization of light directionality prevents lateral light spread that causes interference between adjacent pixels, thereby improving image quality while maintaining adequate viewing angles.
4Adaptability or versatility
If viewing angles of blue, green, and red light emitted in one pixel are different from each other, then color characteristics vary with angle, but it is difficult to unify viewing angles and maintain consistent RGB mixing ratio
Solution Approach 1:
The patent designs the housing and lens with specific optical properties that uniformly control the emission angles of all color channels (red, green, blue). This localized optical control ensures that light from each LED chip is directed at consistent angles, maintaining stable RGB mixing ratios across different viewing angles and preventing color shift variations.
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 sub-pixel area, reduces manufacturing time, and unifies the viewing angles of colors, enhancing image quality and brightness while simplifying the manufacturing process.
Implementation Method 1
a first light emitting stack configured to emit red light, a second light emitting stack disposed on the first LED stack and configured to emit blue light, and a third light emitting stack disposed on the second LED stack and configured to emit green light
Data Source
AI summary
A display apparatus including a display substrate, a plurality of light emitting devices disposed on the display substrate, at least one of the light emitting devices including a first LED sub-unit, a second LED sub-unit disposed on the first LED sub-unit, and a third LED sub-unit disposed on the second LED sub-unit, and a molding layer covering side surfaces of the light emitting devices and exposing upper surfaces thereof, in which the third LED sub-unit is disposed closer to an upper surface of the light emitting device than the first LED sub-unit.