Stacked Micro LED Pixel Structure for Brightness and Color Purity
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Solution Overview
Problem
Conventional micro LED display devices face challenges in manufacturing due to the small form factor of micro LEDs, leading to difficulties in handling and mounting large numbers of LEDs, which can result in reduced brightness and increased complexity in achieving high color purity and reproducibility.
Innovation Solution
A stacked light-emitting diode structure with inclined side surfaces to maximize light reflection using an optically non-transmissive film, allowing for easier manufacturing and increased luminous area without expanding pixel size, and incorporating hydrophilic and shock-absorbing layers for enhanced reliability and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If micro LEDs are arranged on a two-dimensional plane to correspond to each sub-pixel, then the display can achieve high resolution and full color, but the area occupied by one pixel becomes relatively large and handling the micro LEDs becomes difficult due to their small form factor
Solution Approach 1:
The patent transitions from a two-dimensional arrangement of micro LEDs to a three-dimensional stacked structure where red, green, and blue LED chips are vertically stacked. This dimensional change allows multiple sub-pixels to occupy a smaller footprint area while maintaining high color purity and display resolution, effectively resolving the contradiction between high resolution and ease of handling.
Solution Approach 2:
The patent merges multiple micro LED chips (red, green, blue) into a single stacked unit that functions as one pixel. By combining multiple LEDs vertically, the system reduces the total number of discrete components that need to be handled and mounted, thereby improving ease of operation while maintaining display quality.
2Area of stationary object
If the area of each LED chip is reduced to arrange sub-pixels within a limited area, then more sub-pixels can fit in the display, but the brightness of sub-pixels deteriorates due to reduction of light emitting area
Solution Approach 1:
The patent stacks LED chips vertically in the third dimension, allowing multiple high-brightness LEDs to be positioned within a small horizontal footprint. This vertical stacking enables the display to maintain limited pixel area while preserving brightness by utilizing the z-axis for additional light-emitting elements.
Solution Approach 2:
The patent employs a composite structure combining multiple LED chip types (red, green, blue) with different material compositions in a stacked configuration. This composite approach allows each LED to contribute its optimal brightness characteristics while the overall structure maintains a compact pixel area.
3Ease of manufacture
If conventional LEDs are used as backlight sources, then the display can achieve simple manufacturing, but the display cannot generate images directly from light emitting diodes
Solution Approach 1:
The patent segments the display into individually controllable micro LED stacks, where each stack contains red, green, and blue LEDs that can be independently driven. This segmentation enables direct image generation from the LEDs themselves rather than using them as a unified backlight, providing versatility while maintaining manufacturing simplicity through standardized stack construction.
Solution Approach 2:
The stacked LED structure serves multiple functions: it acts as both the light source and the image-generating element. The same LED stacks that could function as backlights can also be individually controlled to produce images directly, providing adaptability without requiring separate manufacturing processes.
4Measurement precision
If a large number of micro LEDs are mounted on a substrate to achieve high resolution, then the display quality improves, but the manufacturing complexity and time increase significantly
Solution Approach 1:
The patent merges multiple micro LEDs into stacked units that can be handled and mounted as single components. By combining red, green, and blue LEDs into one stack, the system reduces the total component count by a factor of three, directly improving manufacturing productivity while maintaining high display resolution through the vertical arrangement.
Solution Approach 2:
By moving from a two-dimensional array of individual LEDs to a three-dimensional stacked structure, the patent reduces the number of mounting locations required on the substrate. This dimensional reorganization allows high-resolution displays to be manufactured with fewer discrete mounting operations, thereby increasing productivity.
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 approach simplifies the manufacturing process, enhances the reliability of micro LED displays by reducing disconnection risks and peeling issues, and maintains brightness while achieving high color purity and reproducibility.
Implementation Method 1
the light reflection effect of the optically non-transmissive film may be maximized or substantially increased
Implementation Method 2
incorporating hydrophilic and shock-absorbing layers for enhanced reliability and adhesion
Implementation Method 3
incorporating hydrophilic and shock-absorbing layers for enhanced reliability and adhesion
Data Source
AI summary
A display apparatus including a substrate, and pixel regions and at least one separation region between the pixel regions, each pixel region including a first LED stack, a second LED stack adjacent to the first LED stack, a third LED stack adjacent to the second LED stack and each having a side surface forming a first angle, a second angle, and a third angle with the substrate, respectively, electrode pads electrically connected to the first, second, and third LED stacks, and an insulation layer disposed on at least one of the first, second, and third LED stacks, in which the first LED stack is configured to emit light having a longer peak wavelength than that emitted from the second and third LED stacks, and the first angle is different from the second and third angles.