Solid-State Image Pickup Device Pixel Timing Control
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Solution Overview
Problem
Existing solid-state image pickup devices require long LED light emission times when separating visible light and infrared light, as they need to be irradiated over two frames for effective signal separation, leading to inefficient light exposure times.
Innovation Solution
A solid-state image pickup device with a pixel array unit and a light exposure control unit that allows for differential light exposure times between pixels, controlling the start and end times of light exposure based on the emission time of predetermined light, enabling one-frame complete operation and reducing background light influence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If infrared light irradiation is performed over two frames to separate visible light and infrared light signals, then light separation precision is improved, but light exposure time increases
Solution Approach 1:
The pixel array is divided into first pixels and second pixels with different light exposure timing. First pixels perform light exposure during both visible light and infrared light periods, while second pixels perform light exposure only during visible light period. This segmentation allows simultaneous acquisition of mixed signals and visible light signals within a single frame, enabling separation without extending total exposure time.
Solution Approach 2:
The patent employs periodic illumination with visible light and infrared light at different time periods within a single frame exposure. By controlling the timing of visible light and infrared light emission in periodic cycles, the system captures different signal components at different time periods, achieving signal separation through temporal multiplexing without requiring multiple frames.
2Reliability
If long LED light emission time is used for infrared light irradiation over two frames, then signal separation completeness is improved, but frame rate decreases
Solution Approach 1:
The system performs preliminary timing coordination by pre-synchronizing the LED light emission periods with the pixel exposure periods. Visible light and infrared light are emitted in predetermined time slots before the actual image capture begins, ensuring that first and second pixels capture the intended signals without requiring extended exposure time or multiple frames.
Solution Approach 2:
The patent implements dynamic control of light exposure timing for different pixel groups. The light exposure control unit dynamically adjusts the exposure start and end times for first pixels versus second pixels based on the illumination timing of visible and infrared light sources. This dynamic timing adjustment enables complete signal separation within a single frame period, maintaining high frame rates while ensuring reliable separation.
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 allows for shortened light exposure times, improved adaptability to moving objects, and increased frame rates by eliminating unnecessary light exposure time, while maintaining effective separation of visible and infrared light signals.
Implementation Method 1
a pixel array unit on which pixels are two-dimensionally arranged
Data Source
AI summary
The present disclosure relates to a solid-state image pickup device that is adapted to enable the light exposure time to be shortened, and an image pickup method, and an electronic apparatus. One pixel and the other pixel differ in the timing in which light exposure is started and in the timing in which the light exposure is ended. During the light exposure time of the one pixel, active light starts light emission, and completes the light emission. For example, before or after the light emission of the active light, the one pixel starts light exposure, and ends the light exposure. The other pixel starts light exposure in the timing in which the time Ta1 has passed after the active light starts light emission (the time Ta2 until the end of irradiation remains), and ends the light exposure after the light exposure of the one pixel ends. The present disclosure can be applied to, for example, an image pickup device that performs image pickup by using active light.