Micro-LED Reflective Electrode Structure for Side Lobe Control
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Solution Overview
Problem
Micro-LED displays face challenges in quickly and accurately transferring millions of micro-LEDs to a display panel, leading to increased transfer error rates and reduced yield, while also struggling with luminance side lobes, sensitivity to chip geometry, and low light efficiency, which affect color viewing angle and ambient contrast ratio.
Innovation Solution
The semiconductor light emitting device incorporates a first reflective electrode layer on the side surface and a scattering structure layer at the bottom, along with a light absorbing layer under the pixel structure, to improve light efficiency, reduce luminance side lobes, and enhance color viewing angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a micro-LED chip with large side surface area is used, then the light output in side direction increases, but luminance side lobes occur and light efficiency decreases
Solution Approach 1:
The patent converts the harmful side emission light into beneficial upward light by placing a reflective electrode layer on the side surface of the micro-LED chip. This reflective layer reflects the side-emitted light upward toward the viewer, transforming the harmful lateral light distribution into a beneficial vertical light distribution that improves both light efficiency and viewing angle characteristics
Solution Approach 2:
The patent employs a composite structure combining the micro-LED chip with a reflective electrode layer made of specific materials (such as aluminum or silver) on its side surface. This composite structure modifies the light emission pattern by combining the LED's inherent emission characteristics with the reflective properties of the electrode material, achieving optimized light distribution
2Ease of manufacture
If the micro-LED chip geometry varies, then manufacturing becomes easier, but light output profile becomes sensitive and color viewing angle deteriorates
Solution Approach 1:
The patent changes the geometric parameters of the reflective electrode layer (such as its height, width, and position) to optimize light reflection. By carefully designing these parameters, the system achieves insensitivity to minor variations in micro-LED chip geometry while maintaining consistent light output profile and color viewing angle characteristics across different chips
Solution Approach 2:
The patent applies local quality modification by placing the reflective electrode layer specifically on the side surface of the micro-LED chip rather than uniformly across the entire structure. This localized approach allows precise control over light reflection in critical areas while maintaining manufacturing tolerance for chip geometry variations
3Productivity
If self-assembly method is used for transfer, then large-screen display assembly is enabled, but transfer error rate increases
Solution Approach 1:
The patent enables self-assembly of micro-LED chips on the display panel by designing the chip structure with integrated electrodes and reflective layers that facilitate automatic positioning and alignment. The chips can find their own assembly positions through fluid manipulation, achieving high-speed assembly of millions of chips while maintaining acceptable transfer accuracy through structural design rather than complex external positioning mechanisms
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 enhances light output efficiency, reduces sensitivity to chip geometry, improves color viewing angle, and increases yield by addressing luminance side lobes and ambient contrast ratio.
Implementation Method 1
Incorporating a first reflective electrode layer on the side surface and a scattering structure layer at the bottom of the micro-LED chip, along with a light absorbing layer under the pixel structure, to control light emission and reduce side lobes
Implementation Method 2
Incorporating a first reflective electrode layer on the side surface and a scattering structure layer at the bottom of the micro-LED chip
Data Source
AI summary
The embodiment relates to a semiconductor light emitting device for a display panel and a display device including the same. The semiconductor light emitting device can include a light emitting structure comprising a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer, a first electrode layer electrically connected to the first conductivity type semiconductor layer, a second reflective electrode layer electrically connected to the second conductivity-type semiconductor layer, a passivation layer disposed on the light emitting structure, a first reflective electrode layer disposed on a side surface of the light emitting structure. The first reflective electrode layer can include a first-first reflective electrode layer in contact with a side surface of the light emitting structure and a first-second reflective electrode layer connected to the first-first reflective electrode layer and disposed on the passivation layer.