Imaging Device Pixel Exposure Timing Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Imaging devices with multiple photoelectric converters face image quality degradation due to unintended photoelectric conversion from invisible illuminating light, particularly when near-infrared light affects photoelectric converters sensitive to visible light wavelengths, causing color shifts and distortion in images of moving objects.
Innovation Solution
The implementation of an imaging device with separate first and second photoelectric converters, each sensitive to different wavelength ranges, where the exposure period of the second converter does not overlap with the light-emitting period of the lighting, and the use of a global shutter method controlled by voltage changes to prevent unintended signal charge generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple photoelectric converters are used to capture different wavelength ranges, then imaging capability is improved, but image quality deteriorates due to unintended photoelectric conversion from invisible illuminating light
Solution Approach 1:
The imaging device segments the photoelectric conversion function into multiple converters with different spectral sensitivities. Each converter is dedicated to specific wavelength ranges (visible, near-infrared, etc.), allowing simultaneous capture of different spectral bands while preventing cross-contamination from illuminating light through temporal separation of exposure periods
Solution Approach 2:
The patent implements periodic action by sequentially controlling the exposure periods of different photoelectric converters. The exposure period of each converter is timed to avoid overlap with the light-emitting period of illumination sources, creating a periodic on/off pattern that prevents unintended photoelectric conversion while maintaining imaging capability across multiple wavelength ranges
2Measurement precision
If exposure period of second photoelectric converter overlaps with light-emitting period, then signal charge is generated, but unintended photoelectric conversion occurs causing color shifts and distortion
Solution Approach 1:
The system applies preliminary anti-action by proactively controlling the exposure timing of the second photoelectric converter to prevent unintended photoelectric conversion before it occurs. The exposure period is set to avoid overlap with the light-emitting period of illumination sources, thereby preemptively eliminating the harmful effect of color shifts and distortion caused by near-infrared light affecting visible light-sensitive converters
3Ease of operation
If rolling shutter method is used for sequential row exposure, then pixel-by-pixel accessibility is achieved, but distorted images result for high-speed moving objects
Solution Approach 1:
The patent merges the exposure operation of multiple photoelectric converters to achieve simultaneous exposure across all pixels. By coordinating the exposure periods of different converters and using a global shutter mechanism, the system captures the entire scene at one moment, eliminating the temporal distortion that occurs with sequential row-by-row exposure while maintaining pixel accessibility
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 configuration reduces image quality degradation by preventing unintended photoelectric conversion and improves image clarity, especially in capturing near-infrared and visible light images simultaneously, while also reducing distortions from moving objects.
Implementation Method 1
a first photoelectric converter that generates first signal charge by photoelectric conversion and that has sensitivity to a first wavelength range that is invisible
Implementation Method 2
a second photoelectric converter that generates second signal charge by photoelectric conversion and that has sensitivity to a second wavelength range
Data Source
AI summary
An imaging device includes a first pixel and a second pixel. The first pixel includes a first photoelectric converter that generates first signal charge by photoelectric conversion and that has sensitivity to a first wavelength range that is invisible and a first signal detection circuit connected to the first photoelectric converter. The second pixel includes a second photoelectric converter that generates second signal charge by photoelectric conversion and that has sensitivity to a second wavelength range and a second signal detection circuit connected to the second photoelectric converter. An exposure period of the second photoelectric converter does not overlap a light-emitting period of light based on lighting, the light being incident on the first photoelectric converter and having a luminescence peak in the first wavelength range. A readout period during which the second signal detection circuit reads out the second signal charge does not overlap the light-emitting period.