Imaging Element Charge Emitter Dynamic Range Photon Counting
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Solution Overview
Problem
Distance measurement devices using light-receiving arrays with single-photon avalanche diodes face challenges in achieving high dynamic range photon counting, especially under strong background light conditions due to nonlinear compression ratios and limitations in charge storage.
Innovation Solution
The implementation of a light-receiving element with a charge emitter that outputs charges to a storage element over a time-varying potential barrier, allowing for precise control of charge emission and storage, enabling photon counting across a higher dynamic range without altering the voltage value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light receiving unit performs photon counting by storing charge amounts corresponding to the number of photons received in a capacitor, then the device can measure distance by counting reflected photons, but the nonlinear compression ratio of the charge amount is insufficient, making it difficult to perform photon counting in a high dynamic range under strong background light
Solution Approach 1:
The patent applies the dynamics principle by introducing a time-varying potential barrier that dynamically adjusts the charge emission rate from the charge emitter. The potential barrier varies over time to control the flow of charges to the storage element, enabling the system to adapt to different light conditions and achieve high dynamic range photon counting. This dynamic control allows the nonlinear compression ratio to be optimized for both weak and strong background light environments.
2Measurement precision
If pulse light is emitted multiple times in one exposure period to perform photon counting, then the distance measurement can be performed, but the charge storage capacity limits the ability to accurately count photons under strong background light conditions
Solution Approach 1:
The patent applies the parameter changes principle by modifying the potential barrier parameter over time. The time-varying potential barrier controls the emission rate of charges from the charge emitter, effectively changing the charge storage dynamics. This allows the system to handle varying quantities of photons under different background light conditions while maintaining accurate distance measurement, overcoming the limitation of fixed charge storage capacity.
3Adaptability or versatility
If the nonlinear compression ratio is increased to improve dynamic range, then photon counting in high dynamic range becomes possible, but the complexity of the charge emission control mechanism increases
Solution Approach 1:
The patent resolves the complexity issue by using a time-varying potential barrier that can be controlled through a relatively simple temporal modulation scheme. Rather than requiring complex spatial or structural modifications, the system achieves high dynamic range through temporal dynamics of the potential barrier, which controls the charge emission rate in a manageable way while maintaining device simplicity.
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 the dynamic range of photon counting to twice that of existing systems, allowing for accurate measurement in environments with varying light conditions, effectively overcoming the limitations of previous technologies.
Implementation Method 1
a light-receiving element; a first storage element; and a charge emitter provided in each of the plurality of pixels, the charge emitter being configured to emit charges to the first storage element for a certain period of time when the light-receiving element detects light emitted from the light source and reflected by a subject
Implementation Method 2
the charge emitter being configured to emit charges to the first storage element for a certain period of time when the light-receiving element detects light emitted from the light source and reflected by a subject over a time varying potential barrier
Data Source
AI summary
An imaging element includes a light source and a plurality of pixels. Each of the plurality of pixels includes: a light-receiving element; a first capacitor, and a charge emitter provided in each of the plurality of pixels, the charge emitter being configured to emit a charge to the first capacitor for a certain period of time ΔT when the light-receiving element detects light emitted from the light source and reflected by a subject.