TOF Sensor Multiple Capacitor Segmentation for Extended Range
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Solution Overview
Problem
Time of Flight (TOF) optical sensors face challenges in accurately measuring distance due to limitations in reliable recovery and representation of reflected light pulse time-related characteristics, especially with single-capacitor architectures requiring multiple cycles and pulses, and issues with capacitor mismatches affecting measurement accuracy.
Innovation Solution
A TOF sensor device employing multiple measuring capacitors per pixel, where each capacitor is used in a specific role for each measuring sequence, and the roles are permuted across sequences to aggregate data for accurate distance determination, minimizing the need for extensive calibration and compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple measuring sequences with permuted capacitor roles are used, then measurement precision and detection range are improved, but device complexity increases
Solution Approach 1:
The photo-detector is divided into multiple independent measuring capacitors (first, second, and third measuring capacitors), each capable of independent charge storage. This segmentation allows parallel measurement of different time intervals, enabling extended detection range and improved precision without requiring sequential measurements that would increase temporal complexity.
Solution Approach 2:
The roles of the measuring capacitors are dynamically permuted across different measuring sequences. In the first sequence, the first capacitor measures a first time interval, in the second sequence the second capacitor measures a second time interval, and in the third sequence the third capacitor measures a third time interval. This dynamic role assignment allows the system to cover extended time ranges while maintaining a fixed hardware architecture.
2Device complexity
If single-capacitor architecture is used, then device complexity is reduced, but measurement precision and detection range are limited
Solution Approach 1:
Multiple measuring capacitors are merged within a single photo-detector pixel, allowing simultaneous charge storage from multiple time intervals. The first, second, and third measuring capacitors collectively capture reflected light pulses across extended time ranges, achieving precision and range improvements while maintaining integration within a compact sensor architecture.
Solution Approach 2:
The system performs periodic measuring sequences with different gating signal timing configurations. Each sequence permutes which capacitor measures which time interval, allowing the system to systematically cover extended detection ranges through repeated measurements with varying configurations, thereby improving precision through multiple sampling opportunities.
3Measurement precision
If extensive pixel-level calibration is performed, then measurement precision is improved, but time and computing resources are consumed
Solution Approach 1:
The multiple measuring capacitors with permuted roles enable the sensor to self-calibrate through intrinsic measurement redundancy. By comparing measurements from different capacitors across different sequences, the system can identify and compensate for capacitor mismatches automatically, reducing the need for external calibration procedures and minimizing calibration time and computational overhead.
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 enhances the accuracy and extends the detection range of TOF sensors without requiring extensive pixel-level calibration, saving time, memory, and computing resources, while improving sensor response time.
Implementation Method 1
an emitter component configured to emit a light pulse
Implementation Method 2
measuring the time of flight of the light
Implementation Method 3
a photo device configured to generate electrical energy in proportion to a quantity of received light
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A time of flight sensor device is capable of extending its total sensing distance using multiple measuring sequences for each distance measuring operation. Such embodiments can execute two or more iterations of a measuring sequence, where the gating signal control sequence for each measuring sequence is offset in time relative to a previous sequence. This yields a greater number of sampling points within which a reflected pulse can be detected and measured, resulting in a total measurable time of flight range that is greater than a measuring operation that uses a fixed timing for the gating signals.