Photon Counting Image Sensor with Synchronized Sub-Pixel Pulse Serialization
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Solution Overview
Problem
Existing image sensors face challenges in accurately counting photons in high illumination conditions due to varying pulse numbers, which requires large memory counters and complicates accurate photon calculation, while in low illumination, the number of pulses decreases, making it difficult to select appropriate counter sizes.
Innovation Solution
The image sensor employs a pixel structure with multiple sub-pixels, where pulse signals from each sub-pixel are synchronized and serialized on a time axis, allowing for accurate counting of photons in both low and high illumination conditions by generating pulse signals based on incident photons and using a counter to output the synchronized and serialized pulse counts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large memory counter is used to accurately count photons in high illumination conditions, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The pixel is divided into multiple sub-pixels, each generating pulse signals independently. By segmenting the photon counting function across multiple sub-pixels with smaller counters, the patent achieves accurate photon measurement in high illumination conditions without requiring a single large memory counter, thus reducing overall device complexity while maintaining measurement precision
Solution Approach 2:
The patent introduces a time dimension by serializing pulse signals from multiple sub-pixels over time. Instead of counting all photons simultaneously requiring large memory, the system processes and counts pulses sequentially in time, enabling accurate photon counting with smaller counters by utilizing temporal dimension for signal integration
2Device complexity
If the counter size is reduced for low illumination conditions, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
By dividing the pixel into multiple sub-pixels, each with its own counter, the system can use smaller counters in low illumination conditions while still achieving accurate overall photon counting through the combined output of multiple sub-pixels, thus reducing device complexity without sacrificing measurement precision
Solution Approach 2:
The patent merges the output signals from multiple sub-pixels through synchronization and serialization. By combining the counting results from multiple smaller counters across sub-pixels, the system achieves the equivalent measurement precision of a single large counter while using smaller, less complex individual counter units
3Measurement precision
If multiple sub-pixels are used to improve photon counting accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent introduces a synchronizer and serializer as intermediary components that manage the output signals from multiple sub-pixels. These intermediaries coordinate the pulse signals from different sub-pixels, enabling accurate photon counting across multiple sub-pixels while simplifying the overall circuit design through standardized signal integration mechanisms
Solution Approach 2:
The synchronizer and serializer serve multiple functions: they synchronize timing across sub-pixels, serialize parallel outputs into sequential signals, and enable universal integration of pulse signals from any number of sub-pixels. This multi-functionality allows the system to improve measurement precision through multiple sub-pixels while managing circuit complexity through a versatile signal processing interface
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 enables accurate photon counting in various illumination conditions, simplifies circuit design, and enhances high-resolution photon counting capabilities, effectively addressing the limitations of existing image sensors.
Implementation Method 1
a photodiode, and a pulse generator respectively connected to the plurality of sub-pixels; pulse generators which are respectively connected to the plurality of sub-pixels, and are configured to generate pulse signals based on electric signals generated based on photons incident on the plurality of sub-pixels
Data Source
AI summary
According to an embodiment, an image sensor using photon counting includes: a plurality of sub-pixels arranged in one pixel; pulse generators which are respectively connected to the plurality of sub-pixels, and are configured to generate pulse signals based on electric signals generated based on photons incident on the plurality of sub-pixels; a synchronizer and serializer configured to synchronize and serialize pulse signals respectively output from the pulse generators; and a counter configured to count and output a number of the pulse signals that are synchronized and serialized.