Emitter Array Layout for Switchable Spot and Flood Illumination
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Solution Overview
Problem
Existing depth mapping systems face challenges in providing a simple, compact, and low-cost illuminator architecture capable of switching between wide-mode spot illumination and narrow-mode flood illumination efficiently.
Innovation Solution
The proposed optoelectronic device features a semiconductor substrate with three sub-arrays of emitters: a first sub-array in the peripheral area, a second sub-array in the central area, and a third sub-array interleaved with the second sub-array, each with distinct pitches and activation configurations. This setup allows for selective activation of the sub-arrays to project patterns of radiation, achieving both wide-mode spot illumination and narrow-mode flood illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single emitter array is used to provide both wide-mode spot illumination and narrow-mode flood illumination, then device complexity is reduced, but the ability to efficiently switch between illumination modes becomes compromised
Solution Approach 1:
The emitter array is segmented into three distinct sub-arrays: a first sub-array for wide-mode spot illumination, a second sub-array for narrow-mode flood illumination, and a third sub-array for enhanced narrow-mode illumination. Each sub-array has a distinct pitch and is positioned in different regions of the substrate. This segmentation allows independent control and activation of each sub-array, enabling efficient switching between illumination modes while maintaining a compact single-array structure.
Solution Approach 2:
Different regions of the emitter array are assigned different local qualities through varying pitch values and microlens configurations. The first sub-array has a larger pitch optimized for wide-angle spot illumination, while the second and third sub-arrays have finer pitches optimized for narrow-angle flood illumination. This local quality differentiation enables each region to perform its specific function optimally while contributing to the overall multi-mode capability of the single array.
2Adaptability or versatility
If multiple separate emitter arrays are used for different illumination modes, then illumination mode performance is optimized, but device complexity and cost increase
Solution Approach 1:
Multiple emitter sub-arrays with different pitches and functions are merged into a single integrated emitter array structure on one substrate. The first, second, and third sub-arrays are all fabricated on the same semiconductor substrate with shared conductors and support structures. This merging achieves the functionality of multiple separate arrays while reducing overall device complexity, eliminating the need for multiple discrete components, and simplifying the optical path.
Solution Approach 2:
The single emitter array is designed with universal multi-functionality by incorporating sub-arrays that can perform different illumination functions. The same physical array structure can provide wide-mode spot illumination, narrow-mode flood illumination, and intermediate modes by selectively activating different sub-arrays. This multi-functionality eliminates the need for separate specialized arrays while maintaining optimized performance for each mode.
3Manufacturing precision
If emitters with different pitches are used for different sub-arrays, then illumination pattern precision is improved, but manufacturing complexity increases
Solution Approach 1:
The array is segmented into regions with different pitches, but all sub-arrays are fabricated using the same semiconductor manufacturing processes. The segmentation is achieved through photolithography patterns and conductor routing rather than requiring different fabrication processes. This allows precise pitch control in each sub-array while maintaining ease of manufacture through standard semiconductor fabrication techniques.
Solution Approach 2:
The pitch parameter is changed between sub-arrays to optimize different illumination functions, but these parameter changes are implemented within the constraints of a single fabrication process. The first sub-array uses a larger pitch for wide-mode illumination, while the second and third sub-arrays use finer pitches for narrow-mode illumination. These parameter variations are achieved through design rules and patterning rather than requiring different 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 solution enables a multi-mode illuminator that is simple, compact, and cost-effective, requiring only a single emitter array and projection optics, without moving parts. It effectively supports both wide-mode spot illumination and narrow-mode flood illumination, enhancing the versatility and efficiency of depth mapping systems.
Implementation Method 1
The emitters include vertical-cavity surface-emitting lasers (VCSELs)
Implementation Method 2
optical radiation reflected from the object... electromagnetic radiation in any of the visible, infrared and ultraviolet ranges
Implementation Method 3
the microlenses include on-chip lenses formed respectively on the emitters
Implementation Method 4
projection optics mounted over the semiconductor substrate and configured to project first and second beams emitted by the emitters
Data Source
AI summary
An optoelectronic device includes a semiconductor substrate and an array of emitters disposed on the substrate. The array includes a first sub-array, having a first pitch, disposed in a peripheral area of the substrate, a second sub-array, also having the first pitch, disposed in a central area of the substrate, which is contained within the peripheral area, and a third sub-array, having a second pitch finer than the first pitch, interleaved with the second sub-array in the central area of the substrate. Conductors disposed on the substrate are configured to activate the first, second, and third sub-arrays selectively.