Pixel Modulation Drivers for Time-of-Flight Cameras
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Time-of-flight cameras face challenges in power consumption and electromagnetic interference due to high switching frequency and peak current requirements, especially when only partial image acquisition is needed, leading to inefficiencies in modulation and read-out processes.
Innovation Solution
The implementation of pixel modulation drivers that drive sub-arrays of pixels with individual demodulation signals and enable control, allowing for multiphase modulation schemes and selective region-of-interest (RoI) activation, reducing peak switching current and electromagnetic interference while optimizing power usage through sub-readout modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common demodulation input is used for all pixels, then the device complexity is reduced, but the power consumption increases due to high switching frequency and peak current requirements
Solution Approach 1:
The pixel array is divided into multiple sub-arrays, each driven by its own pixel modulation driver with individual demodulation signals. This segmentation allows independent control of switching moments across sub-arrays, distributing peak current demands and reducing overall power consumption while maintaining adequate depth calculation accuracy.
2Measurement precision
If high switching frequency is used for demodulation, then the depth calculation accuracy is improved, but the electromagnetic interference increases
Solution Approach 1:
The illumination and demodulation processes are organized into periodic frames with multiple phases. By distributing switching moments across different phases and sub-arrays within each frame, the system maintains high switching frequencies necessary for accurate depth calculation while reducing instantaneous electromagnetic interference through temporal distribution of switching events.
3Manufacturing precision
If full array read-out is performed, then the image quality is maintained, but the productivity decreases when only partial acquisition is needed
Solution Approach 1:
The system enables selective activation of specific sub-arrays corresponding to regions of interest within the scene. By activating only the necessary sub-arrays rather than the entire pixel array, the system maintains image quality for the relevant regions while significantly improving acquisition speed and reducing power consumption for partial acquisition scenarios.
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 significantly reduces power consumption and electromagnetic interference, enabling more efficient and robust time-of-flight imaging by distributing switching moments and allowing for higher frame rates in partial acquisition modes without compromising depth calculation accuracy.
Implementation Method 1
a pixel array that collects light reflected from the same region of interest
Implementation Method 2
an illumination unit that illuminates a region of interest with modulated light
Implementation Method 3
determines the distance of objects measuring the time-of-flight (ToF) of a light signal between the camera and the object
Data Source
AI summary
An electronic device (200) having an array of pixels (210; 400; 500; 810), and pixel modulation drivers (D1 to D8), each pixel modulation drivers (D1 to D8) being configured to drive a sub-array (R1 to R8) of the pixels.