Non-Contiguous Photodiode Layouts for Structured Light Detection
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Solution Overview
Problem
Conventional photosensitive detectors, such as SPAD detector arrays, do not achieve optimal efficiency, particularly when structured light is used, due to inefficiencies in integrating photosensitive and non-photosensitive areas.
Innovation Solution
The apparatus and method involve configuring photosensitive regions, such as macro-pixels, with two or more photodiodes arranged in a defined configuration, separated by non-photosensitive regions, allowing selective enabling/disabling of photodiodes based on the detection of a structured light pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If photosensitive pixels and control logic are integrated onto a single package to increase spatial efficiency, then spatial efficiency is improved, but quantum efficiency deteriorates due to the presence of non-photosensitive areas
Solution Approach 1:
The detector is divided into multiple segments including photosensitive regions, non-photosensitive regions, and guard rings. The photosensitive regions are segmented into multiple zones that can be independently controlled, allowing the system to activate only the necessary segments when structured light is detected, thereby maintaining high quantum efficiency while integrating control logic on the same package
Solution Approach 2:
Different regions of the detector are assigned different functional qualities: photosensitive regions for light detection, non-photosensitive regions for control logic, and guard rings for electrical isolation. The system dynamically adjusts the operational state of different local regions based on whether structured light is present, optimizing quantum efficiency locally while maintaining overall spatial integration
2Use of energy by moving object
If structured light patterns are used to illuminate the environment at lower power levels, then power consumption is reduced, but detection efficiency deteriorates with conventional photosensitive detectors
Solution Approach 1:
The detector continuously monitors for the presence of structured light patterns and prepares the photosensitive regions in advance. When structured light is detected, the system pre-configures the appropriate macro-pixels and photodiodes for optimal detection, ensuring high detection efficiency is ready when the structured light pattern arrives, while maintaining low power consumption during non-structured light periods
Solution Approach 2:
The detector dynamically adjusts its operational mode based on the detected light pattern. When structured light is present, the system activates specific macro-pixels and photodiodes configured for high-efficiency structured light detection. When structured light is absent, the system reduces activation to maintain low power consumption. This dynamic adaptation resolves the contradiction between power efficiency and detection efficiency
3Area of stationary object
If multiple photodiodes are arranged in macro-pixels with non-photosensitive regions between them, then fill factor is improved, but device complexity increases
Solution Approach 1:
Multiple photodiodes are merged into macro-pixel groups that function as unified detection units. The non-photosensitive regions between photodiodes within a macro-pixel are shared rather than duplicated, reducing overall device complexity. The macro-pixels are controlled as grouped units, simplifying the control logic while maintaining high fill factor through the combined photosensitive area of multiple photodiodes
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 configuration enhances quantum efficiency and improves signal handling consistency, enabling higher fill factors and optimized performance with structured light patterns.
Implementation Method 1
A photon may generate a carrier in the SPAD through the photo electric effect
Implementation Method 2
The photo generated carrier may trigger an avalanche current in one or more of the SPADs in an SPAD array
Data Source
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AI summary
An apparatus comprising at least one detector configured to receive return light from an object within a detector field of view the light generated by a light source wherein the detector comprises: at least two photosensitive regions (201) configured to receive the return light from the light source; and at least one non-photosensitive region (203), wherein the at least two photosensitive regions (201) are separated by the at least one non-photosensitive region (203) and the at least one non-photosensitive region (203) is associated with one of the at least two photosensitive regions (201).