LCoS Color Pixel Array Fabrication Using Reflective Etching Stops
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Solution Overview
Problem
Conventional LCoS displays face challenges in fabricating micro color filters with different colors on a semiconductor substrate due to complex and costly processes, which hinder the production of small-size reflective color LCoS displays.
Innovation Solution
A method involving the sequential formation of reflective and color filter layers on a semiconductor substrate, using reflective layers as etching stop layers to simplify the process of defining color filter patterns, allowing for the creation of a color pixel array with simple etching processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional methods are used to fabricate micro color filters with inorganic dichroic materials, then color filter layers can be formed, but the fabrication process becomes complicated and expensive with high cost
Solution Approach 1:
The patent introduces a reflective layer as an intermediary etching stop layer between the semiconductor substrate and the color filter layer. This reflective layer serves as a mediator that enables selective etching of the color filter layer without damaging underlying layers, thereby simplifying the fabrication process while maintaining color filter functionality
Solution Approach 2:
The patent segments the color filter structure into multiple layers with different functions: a first color filter layer for light reflection and a second color filter layer for light transmission. This segmentation allows each layer to be optimized independently and simplifies the overall fabrication process by enabling selective etching at different depths
2Adaptability or versatility
If multiple LCoS panels with color separation and combination optical systems are used, then colorful images can be generated, but the device size increases and fabrication cost increases
Solution Approach 1:
The patent merges the color separation functionality into a single LCoS panel by integrating multiple color filter layers (first color filter layer and second color filter layer) with different reflective properties. This combination enables the single panel to perform the color separation function that previously required multiple separate panels and complex optical systems
Solution Approach 2:
The reflective layer is designed to serve multiple functions: it acts as an etching stop layer during fabrication, provides optical reflection for the first color filter layer, and enables selective lighting for different pixel regions. This multi-functionality reduces the need for separate components and simplifies the overall device structure
3Ease of manufacture
If thick transmissive interlayers are formed on color filters, then color filter structures can be built, but the structure becomes too thick to meet small-size requirements
Solution Approach 1:
The patent extracts the etching stop function from a separate thick transmissive interlayer and integrates it directly into the color filter structure itself. The color filter layer is designed to serve as its own etching stop, eliminating the need for additional thick interlayers and reducing overall structure thickness while maintaining fabrication capability
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 approach enables the fabrication of LCoS panels with color pixel arrays using simple processes, reducing fabrication costs and meeting the requirements for small-size displays by allowing the production of colorful images with a single LCoS panel, eliminating the need for complex optical engines.
Implementation Method 1
a first reflective layer, a first color filter layer, a second reflective layer, and a second color filter layer are successively formed on the semiconductor substrate
Data Source
AI summary
A method of fabricating an LCoS display with a color pixel array comprises a step of disposing reflective layers between various color filter layers. The reflective layers are used as etching stop layers between color filter layers so that etching processes are capable of defining patterns of the color filter layers in different sub-pixels for forming the color pixel array.