VCSEL Pixel Structure with Bright and Dark Sub-Pixels
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
VCSEL arrays face inefficiencies in energy usage and information density due to the need for multiple point sources and the vulnerability of the projected image when one or more point sources are damaged, leading to energy waste and potential defects in the projected image.
Innovation Solution
A pixel structure for VCSELs with a combination of bright-area and dark-area sub-pixels arranged in patterns within the emission window, where only bright-area sub-pixels emit light, and dark-area sub-pixels do not, allowing for improved energy efficiency and increased information density through the use of trench, oxide, ion passivation, metal masking, or high threshold reflection layers to control current paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If multiple VCSEL point sources are arranged in an array to form images, then projection function is achieved, but energy efficiency deteriorates due to sacrificial point sources being occluded during projection
Solution Approach 1:
The emission window is segmented into multiple sub-windows, with each sub-window containing a VCSEL point source. This segmentation allows different regions to have different functions: some sub-windows emit light while others remain occluded, enabling image formation without wasting energy from sacrificial sources.
Solution Approach 2:
Different sub-windows within the emission window have different optical properties. Bright-area sub-pixels emit light while dark-area sub-pixels do not, creating local variations in light emission that form the projected image without requiring all point sources to be active simultaneously.
2Ease of manufacture
If VCSEL point sources are arranged in a simple circular or square hole pattern, then manufacturing is simplified, but information density deteriorates because one emission window can only carry one bit of information
Solution Approach 1:
The invention transitions from binary information encoding (one bit per emission window) to multi-bit encoding by dividing each emission window into multiple sub-windows arranged in patterns. This dimensional expansion within the emission window allows each window to carry multiple bits of information through different light emission patterns.
3Productivity
If one or more VCSEL point sources are damaged, then the system remains operational, but image quality deteriorates causing defects in the projected image
Solution Approach 1:
By segmenting the emission window into multiple independent sub-windows, the failure of one VCSEL point source affects only a small portion of the overall projection. The segmented structure isolates failures, preventing them from compromising the entire image and maintaining system operational continuity.
4Loss of information
If bright-area and dark-area sub-pixels are arranged in patterns within the emission window, then information density increases, but device complexity increases due to additional current path control structures
Solution Approach 1:
The current path control structures (trenches, oxide layers, ion passivation layers, metal masking layers) are nested within the VCSEL device structure. These control elements are integrated into the existing device architecture rather than added as separate external components, managing complexity through nested integration.
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 solution enhances energy efficiency, reduces manufacturing costs, and increases the information density and reliability of VCSEL arrays by allowing independent identification of each pixel, enabling more complex patterns and improved application range without additional external masks.
Implementation Method 1
a patterned trench and an oxide layer extending from the sidewall of the trench toward the vertical cavity surface emitting laser
Implementation Method 2
VCSEL's electro-optic conversion efficiency is more than 35%
Data Source
AI summary
A pixel structure for a vertical cavity surface emitting laser has an emission window. The pixel structure includes a plurality of sub-pixels in the emission window. Bright-area sub-pixels emit light and dark-area sub-pixels having no light emission. The bright-area sub-pixels and the dark-area sub-pixels are arranged in a pattern in the emission window. Various patterns are possible. Different structures for implementing the sub-pixels are described.