Single Pixel Sensor Synchronization for Flickering Light
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Solution Overview
Problem
Current imaging systems face challenges in effectively capturing images under varying lighting conditions, particularly with flickering light sources and ambient light, leading to image artifacts and reduced sensitivity due to parasitic light sensitivity issues.
Innovation Solution
A single pixel sensor with a photosensor, charge storage, and transistors configured for repeated signal accumulation and synchronization with light sources, including flickering objects and ambient light, using a gating module to control exposure and reduce blooming, and employing backside illuminated pixel arrays with spectral filters to enhance sensitivity and reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single pixel sensor accumulates signals multiple times per image frame, then sensitivity is improved, but parasitic light sensitivity increases causing image artifacts
Solution Approach 1:
The patent applies periodic action by implementing multiple discrete accumulation cycles within a single image frame. The sensor performs repeated signal accumulation at specific time intervals, allowing selective integration of periodic light signals (such as flickering light sources) while rejecting non-periodic parasitic light. This temporal sampling approach enables the system to achieve high sensitivity for targeted signals while minimizing the impact of continuous background interference.
Solution Approach 2:
The patent implements preliminary action through a gating mechanism that controls the timing of signal accumulation. The gate selectively opens during specific time windows to allow desired light signals to be accumulated while remaining closed during periods when parasitic light would interfere. This preliminary gating action prevents unwanted light accumulation before it can contaminate the signal, thereby maintaining high sensitivity without the corresponding increase in parasitic light sensitivity.
2Measurement precision
If the sensor synchronizes with flickering light sources, then image quality improves, but device complexity increases due to gating control requirements
Solution Approach 1:
The patent merges the gating control functionality with the existing pixel structure by integrating the gate directly into the pixel circuitry. This integration allows the gating mechanism to be controlled through the same readout infrastructure already present in the sensor, eliminating the need for separate complex control systems. The gate is synchronized with the flickering light source frequency, enabling high-quality image capture while keeping the added complexity minimal through this merging approach.
3Measurement precision
If backside illuminated pixel arrays are used, then quantum efficiency increases, but manufacturing complexity increases
Solution Approach 1:
The patent implements backside illumination by inverting the traditional sensor structure, allowing light to enter through the back of the pixel array rather than the front. This inversion places the photosensitive elements directly in the light path without the obstruction of metal interconnect layers, significantly improving quantum efficiency. While this approach increases manufacturing complexity compared to front-illuminated structures, it enables superior optical performance by eliminating light absorption and reflection losses in the metallization layers.
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 solution enables high sensitivity imaging under diverse lighting conditions, minimizing image artifacts and improving dynamic range by synchronizing with flickering sources and reducing ambient light interference, while maintaining low noise levels and high signal-to-noise ratios.
Implementation Method 1
a photosensor configured to convert light into proportional signals
Data Source
AI summary
A single pixel sensor is provided, comprising a photo sensor configured to convert light into proportional signals; a charge storage configured to accumulate, repeatedly, a plurality of the signals converted by the photosensor; a first transistor coupled between a pixel voltage terminal and the photosensor; a second transistor coupled between the photosensor and the charge storage; and a readout circuit coupled between the charge storage and an output channel, wherein: the single pixel sensor is configured to carry out the repeated accumulations of signals multiple times per each readout by the readout circuit, the single pixel sensor is configured to synchronously convert reflections of light emitted by an associated illuminator or to convert light emitted by non-associated flickering light sources, and wherein the single pixel sensor is backside illuminated by the light.