Recently, the BOE research team published a paper titled "Novel Package Design Enhances Optical Efficiency of Micro LED Displays" in the journal "Information Display".
This research proposes an innovative Micro LED packaging solution that has becomeIt has successfully solved the technical problems in the industry such as strong side wall luminescence, low light energy utilization and color shift of micro LED chips.
It is reported that as the pixel size shrinks to less than 50 microns, the side wall area of the chip increases relatively, resulting in enhanced side luminescence and weakened top luminescence of Micro LED, resulting in brightness loss and color deviation, which restricts the application of Micro LED in high-definition display scenarios.
In response to this problem, the BOE research team developed a composite packaging structure composed of high refractive index transparent glue, white high-reflective resin, microlens array and patterned black matrix (BM).
By introducing a gradient refractive index layer on the Micro LED chip, the researchers effectively improved the exit angle of light from the top of the chip, increasing the critical angle from 25 degrees to a maximum of 65.9 degrees, which greatly improved the top light extraction efficiency.
At the same time, the white reflective resin forms an isosceles trapezoidal structure between the chips, which can concentrate and scatter light, increasing the brightness at 0° viewing angle by about 27%, and ensures smooth light emission through the plasma removal of residual colloid process.
In the light control section, the team used nanoimprint technology to prepare a high-precision lens array to achieve effective convergence of light within ±60°.
Simulation results show that when the lens curvature is 0.03 and the refractive index is 1.85, the light intensity is increased by more than 53%. In addition, the research also introduced a patterned black matrix in the packaging glass layer to effectively reduce the reflectivity to less than 2% and achieve a high contrast ratio of more than 20,000:1, significantly improving the display quality.
The BOE research team stated that this solution not only achieves breakthroughs in optical efficiency and uniformity, but also takes into account packaging reliability. The combination of the glass cover and the OCA layer improves the waterproof, anti-oxidation and wear-resistant properties, providing a reliable path for the mass production application of Micro LED in automotive displays, AR/VR headsets, wearable devices and other fields.
BOE has not only obtained the latest Micro LED research results, but also continues to promote the development of Mini/Micro LED direct display technology and applications.
ANNA