Micro Lens LED Display Panel for Light Collimation and Low Crosstalk
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Solution Overview
Problem
Conventional projection systems using passive imager devices like LCDs and DMDs suffer from low efficiency due to the loss of light not transmitted or reflected, requiring complex illumination optics that increase bulkiness and optical loss, while LED displays face issues with light divergence leading to crosstalk and reduced contrast.
Innovation Solution
A monolithically integrated LED display panel with a substrate, pixel driver circuits, an array of LED dies, and a micro lens array that collimates light, combining the light source and image forming functions into a single device to reduce light divergence and enhance efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional passive imager devices (LCD, DMD) are used for projection, then image formation is achieved, but light efficiency is low due to loss of non-transmitted/reflected light and complex illumination optics are required
Solution Approach 1:
The patent merges the light source (LED) and the imager device into a single monolithic integrated structure. Each pixel driver circuit directly controls an LED die, eliminating the need for separate illumination optics and passive modulators. This integration achieves high light efficiency because the LED light is generated directly at the pixel location without being lost through transmission or reflection, while simultaneously reducing device complexity by removing the complex illumination optical system.
Solution Approach 2:
The LED array serves as both the light source and the imager device. Each LED die generates its own light and is directly controlled by its corresponding pixel driver circuit to form images. This self-service approach eliminates the need for external illumination optics to provide light to a separate modulator, thereby improving light efficiency and reducing system complexity.
2Illumination intensity
If LED dies are used as self-emissive imager devices, then light generation is achieved, but light divergence is large causing crosstalk and reduced contrast
Solution Approach 1:
The patent introduces micro lens arrays positioned above the LED array, with each micro lens corresponding to a specific LED die. The micro lens has a localized focusing function that directs the divergent light from its associated LED die into a concentrated beam. This local quality control ensures that light from each pixel is directed precisely, preventing crosstalk with adjacent pixels while maintaining high illumination intensity from each LED.
3Object-affected harmful factors
If micro lens array is added to collimate LED light, then light divergence is reduced and crosstalk is minimized, but device complexity increases
Solution Approach 1:
The micro lens array is monolithically integrated with the LED array and driver circuit array on the same substrate. The micro lenses are positioned in direct alignment with the LED dies through precise patterning processes, forming a unified structure. This integration minimizes the increase in device complexity because the micro lens array becomes an inseparable part of the LED display panel fabrication process, rather than a separate component that needs to be assembled and aligned manually.
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
The solution improves light utilization and reduces crosstalk, increasing the brightness and efficiency of LED-based projection systems while minimizing power consumption and bulkiness.
Implementation Method 1
a micro lens array including a plurality of micro lenses each corresponding to and being arranged over at least one of the LED dies
Data Source
AI summary
A light-emitting diode (LED) display panel includes a substrate, a driver circuit array on the substrate and including a plurality of pixel driver circuits arranged in an array, an LED array including a plurality of LED dies each being coupled to one of the pixel driver circuits, a micro lens array including a plurality of micro lenses each corresponding to and being arranged over at least one of the LED dies, and an optical spacer formed between the LED array and the micro lens array.