Range Sensor Segmented Charge Regions for Distance Accuracy
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Solution Overview
Problem
The existing Time-Of-Flight (TOF)-type range image sensors face issues with charge transfer efficiency due to potential gradients, leading to inaccurate distance detection, as charges migrate to incorrect regions, and background light accumulation causes saturation, reducing the accuracy of distance measurement.
Innovation Solution
A range sensor design with a charge generating region, signal charge collecting region, and unnecessary charge collecting region, utilizing photogate and transfer electrodes to control charge migration, improving transfer efficiency and reducing background light accumulation, thereby enhancing distance detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a potential gradient is formed across the charge generating region, then charges migrate to the charge collecting region, but some charges migrate to the charge discharging region causing deteriorated transfer efficiency
Solution Approach 1:
The charge collecting structure is segmented into an inner charge collecting region surrounded by the charge generating region and an outer charge discharging region surrounding the charge generating region. This segmentation allows selective collection of signal charges in the inner region while directing unnecessary charges to the outer region, improving charge transfer efficiency and distance detection accuracy.
Solution Approach 2:
Different regions are assigned different functions: the inner charge collecting region collects signal charges from specific directions, while the outer charge discharging region collects unnecessary charges. The gate electrodes are also differentiated into inner and outer gates with different control signals, creating local quality variations that optimize charge collection efficiency.
2Productivity
If the outside discharge gate electrode has a relatively large area to discharge unnecessary charges, then charge discharge capability is improved, but charge transfer efficiency to the charge collecting region deteriorates
Solution Approach 1:
The charge collecting structure is segmented into an inner charge collecting region surrounded by the charge generating region and an outer charge discharging region surrounding the charge generating region. This segmentation allows selective collection of signal charges in the inner region while directing unnecessary charges to the outer region, improving charge transfer efficiency and distance detection accuracy.
Solution Approach 2:
The charge generating region acts as an intermediary structure between the inner charge collecting region and the outer charge discharging region. It generates charges in response to incident light and directs them to appropriate regions based on the potential gradients created by the gate electrodes, enabling both efficient signal charge collection and unnecessary charge discharge.
3Reliability
If background light charges accumulate in the charge discharging region, then the charge discharge function is maintained, but the accumulation capacity saturates causing deteriorated distance detection accuracy
Solution Approach 1:
The outer charge discharging region is designed to actively discard unnecessary charges including those from background light by maintaining a potential gradient that directs these charges away from the inner charge collecting region. This prevents saturation and maintains distance detection accuracy over extended operation periods.
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
The improved charge transfer efficiency and reduced background light accumulation enhance the accuracy of distance detection, increasing spatial resolution and reducing deviations in distance calculation.
Implementation Method 1
a charge generating region configured to generate charges in response to incident light
Implementation Method 2
a transfer electrode disposed between the signal charge collecting region and the charge generating region, and configured to cause the signal charges from the charge generating region to flow into the signal charge collecting region in response to an input signal
Implementation Method 3
an unnecessary charge collecting gate electrode disposed between the unnecessary charge collecting region and the charge generating region, and configured to cause the unnecessary charges in the charge generating region to flow into the unnecessary charge collecting region in response to an input signal
Data Source
AI summary
A signal charge collecting region is disposed inside a charge generating region so as to be surrounded by the charge generating region, and collects signal charges from the charge generating region. An unnecessary charge collecting region is disposed outside the charge generating region so as to surround the charge generating region, and collects unnecessary charges from the charge generating region. A transfer electrode is disposed between the signal charge collecting region and the charge generating region, and causes the signal charges from the charge generating region to flow into the signal charge collecting region in response to an input signal. An unnecessary charge collecting gate electrode is disposed between the unnecessary charge collecting region and the charge generating region, and causes the unnecessary charges from the charge generating region to flow into the unnecessary charge collecting region in response to an input signal.