Multi-step Microlens Array for AR Display Brightness
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Solution Overview
Problem
Current AR display products using optical waveguides face low light efficiency, requiring luminous brightness greater than 2000 nits, which is not met by existing display devices with microlens arrays, especially for smaller microlens sizes below 10 microns, as traditional manufacturing processes like laser processing or hot-melt become complicated and costly.
Innovation Solution
A display apparatus with a multi-step structured microlens array manufactured using an overlay lithography process, where the microlens regions are divided into sampling regions based on a phase-transform function, forming a multi-step structure that enhances light convergence and brightness, reducing manufacturing complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional laser processing or hot-melt process is used to manufacture microlens with large size (above tens of microns), then the microlens can be manufactured, but the manufacturing complexity and cost increase significantly for smaller microlens sizes below 10 microns
Solution Approach 1:
The microlens manufacturing process is segmented into multiple lithography steps, where each step forms a portion of the final microlens structure. This allows precise control over microlens dimensions down to sub-10 micron scales by dividing the complex shaping process into manageable patterning stages, thereby maintaining manufacturing precision while controlling process complexity through standardized lithography techniques.
Solution Approach 2:
The invention transitions from conventional single-step lens shaping to a multi-layered approach where microlens structures are built up through sequential lithography steps creating different height levels. This dimensional approach allows precise control of microlens optical properties by manipulating the vertical profile through multiple patterning layers, achieving high precision manufacturing for small microlens sizes.
2Illumination intensity
If optical waveguide is used for AR display product, then the product can be made thin and light, but the light efficiency is relatively low requiring luminous brightness greater than 2000 nits
Solution Approach 1:
The microlens array implements local quality optimization by creating regions with different optical properties. Each microlens is precisely engineered with specific curvature and height characteristics tailored to its position in the array, enabling localized light concentration and direction control. This allows the system to achieve high luminous brightness at specific viewing angles while maintaining overall energy efficiency of the optical waveguide system.
Solution Approach 2:
The invention employs composite optical structures combining the optical waveguide material with microlens array structures. The microlens array acts as an optical coupling layer that efficiently transfers light from the display device into the waveguide, minimizing energy loss at the interface and enhancing overall light efficiency while enabling the thin and light product form factor.
3Illumination intensity
If microlens array layer is provided on display device to enhance luminous brightness at central viewing angle, then display requirements are met, but the manufacturing process becomes more complex
Solution Approach 1:
The multi-step lithography process serves multiple functions simultaneously: it defines the microlens footprint, controls the lateral dimensions, and creates the vertical height profile through selective etching or deposition at each step. This multi-functional approach consolidates what would otherwise require separate manufacturing processes into a single integrated lithography workflow, reducing overall manufacturing complexity while achieving the required luminous brightness enhancement.
Solution Approach 2:
The lithography process performs preliminary structuring by pre-defining the microlens pattern and height profile before final assembly. By establishing the complete microlens architecture through sequential patterning steps prior to waveguide integration, the invention simplifies subsequent manufacturing steps and reduces the complexity of assembling the final AR display product.
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 increases light brightness by about 10-40% within ±9 degrees, meeting display requirements while enabling thinner and lighter AR products with improved user experience, and simplifies the manufacturing process for smaller microlens sizes.
Implementation Method 1
each microlens in the microlens array includes a multi-step structure having a plurality of steps
Implementation Method 2
enhances the luminous brightness at a central viewing angle (±9 degrees) of the display device
Data Source
AI summary
A display apparatus and a method of manufacturing the same are provided. The display apparatus includes a substrate, and a plurality of display devices, an encapsulation layer, a microlens array and a protective layer which are sequentially provided on the substrate, and the microlens array includes a plurality of microlenses corresponding to the plurality of display devices, and each microlens in the microlens array comprises a multi-step structure including a plurality of steps.