LED Display Microlens Structure for Uniform Subpixel Output
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Solution Overview
Problem
Existing display apparatuses using LEDs as pixels face challenges in achieving high light uniformity between subpixels due to variations in luminous efficiency across different color-emitting LED cells, particularly those emitting longer wavelengths.
Innovation Solution
The display apparatus is designed with LED cells of varying widths and active layer quantum well layer configurations to match luminous efficiency, where cells emitting longer wavelengths have larger areas and more quantum well layers, and microlenses are used to converge light uniformly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If LED cells of different colors are used in display apparatuses, then color diversity is achieved, but light uniformity deteriorates due to variations in luminous efficiency across different color-emitting LED cells
Solution Approach 1:
The patent applies local quality by configuring different numbers of quantum well layers in different colored LED cells. Specifically, red LED cells are configured with 5 quantum well layers, green LED cells with 3 quantum well layers, and blue LED cells with 2 quantum well layers. This localized differentiation in structural quality compensates for the inherent luminous efficiency variations across different colors, thereby achieving uniform light output while maintaining color diversity.
2Use of energy by moving object
If the number of quantum well layers is increased in LED cells emitting longer wavelengths, then luminous efficiency is improved, but device complexity increases
Solution Approach 1:
The patent applies parameter changes by systematically varying the number of quantum well layers based on the emission wavelength of each LED cell. Red LED cells (longer wavelength) are configured with 5 quantum well layers, green LED cells with 3 layers, and blue LED cells (shorter wavelength) with 2 layers. This parameter differentiation optimizes luminous efficiency for each color while maintaining a manageable structural complexity through a systematic configuration approach.
3Illumination intensity
If microlenses are used to converge light uniformly, then light uniformity is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by configuring microlenses with different focal lengths corresponding to different colored LED cells. Red LED cells are equipped with microlenses having a first focal length, green LED cells with microlenses having a second focal length, and blue LED cells with microlenses having a third focal length. This localized optimization of microlens parameters achieves uniform light convergence while following systematic manufacturing processes.
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 design enhances light uniformity and reduces output variations among subpixels, improving color reproduction and overall display quality.
Implementation Method 1
a reflective layer on the passivation layer, the reflective layer configured to emit light toward upper surfaces of the plurality of LED cells
Implementation Method 2
a plurality of microlenses respectively on the plurality of subpixels
Data Source
AI summary
A display apparatus includes a circuit board including a driving circuit, a pixel array on the circuit board and including unit pixels, each of the unit pixels including a plurality of subpixels, and a plurality of microlenses respectively on the plurality of subpixels, where the pixel array further includes a plurality of light-emitting diode (LED) cells each respectively including a first conductivity-type semiconductor layer, an active layer, and a second conductivity-type semiconductor layer that are sequentially stacked, a passivation layer on side surfaces and lower surfaces of the plurality of LED cells, a reflective layer on the passivation layer, the reflective layer configured to emit light toward upper surfaces of the plurality of LED cells, a gap-fill insulating layer on the side surfaces and lower surfaces of the plurality of LED cells, and a first connection electrode on the gap-fill insulating layer, and connected to the first conductivity-type semiconductor layers.