Phase-Shifted Ranging Sensor for Cyclic Error and IR Drop Control
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Solution Overview
Problem
Existing ranging sensors face challenges in simultaneously reducing cyclic errors and dispersing drive current, leading to issues like IR drops, electromagnetic interference, and cyclic errors due to the processing of rectangular light waves as sine waves.
Innovation Solution
A ranging sensor with a phase shift circuit that generates phase-shifted drive pulse signals to distribute pixel drives in a time division manner, accumulating charges based on these signals and outputting detection signals, thereby approximating a sine wave and dispersing drive current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If all pixels are driven simultaneously to increase productivity, then the number of pixels can be increased, but concentration of drive current generates intense charge/discharge current causing IR drop and measurement errors
Solution Approach 1:
The patent divides the pixel array into multiple groups that are driven in sequential time slots rather than simultaneously. Each group of pixels is activated at different times within a frame period, which disperses the drive current and prevents intense charge/discharge currents that cause IR drop. This segmentation of the drive timing allows high-resolution pixel arrays to be operated without measurement errors.
Solution Approach 2:
The patent implements periodic driving of pixel groups in a time-division manner, where each group is activated in alternating time slots within a frame period. This periodic activation pattern ensures that drive current is distributed over time rather than concentrated, preventing IR drop while maintaining the ability to drive a large number of pixels for high productivity.
2Measurement precision
If phase shift is applied to reduce cyclic errors, then measurement accuracy can be improved, but drive current dispersion is not achieved leading to IR drop
Solution Approach 1:
The patent combines phase shift technology with time-division drive segmentation. Pixels are not only phase-shifted for cyclic error reduction but also divided into multiple groups that are activated in different time slots. This dual approach ensures both measurement precision through phase shifting and reliable current distribution through temporal segmentation of the drive signal.
Solution Approach 2:
The patent implements periodic driving of pixel groups in alternating time slots within a frame period. This periodic activation pattern ensures that drive current is distributed over time rather than concentrated, preventing IR drop while maintaining the ability to drive a large number of pixels for high productivity.
3Productivity
If large number of pixels are driven simultaneously to improve productivity, then output can be increased, but electromagnetic interference and IR drop occur reducing device stability
Solution Approach 1:
The patent segments the pixel array into multiple groups that are driven in sequential time slots. This segmentation disperses the electromagnetic emissions over time, preventing the intense simultaneous switching that causes EMI and IR drop. The segmented approach maintains high output capability while ensuring electromagnetic compatibility and system stability.
Solution Approach 2:
The patent implements periodic driving of pixel groups in alternating time slots within a frame period. This periodic activation pattern ensures that drive current is distributed over time rather than concentrated, preventing IR drop while maintaining the ability to drive a large number of pixels for high productivity.
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 effectively reduces cyclic errors and drive current, preventing IR drops and electromagnetic interference, and maintaining electromagnetic compatibility, while achieving accurate depth measurements.
Implementation Method 1
a pixel that accumulates electric charges on the basis of the phase-shifted drive pulse signal and outputs a detection signal corresponding to the accumulated electric charges, the electric charges being obtained by photoelectrically converting reflected light
Data Source
AI summary
Ranging sensors with reduced cyclic errors and drive current dispersion are disclosed. In one example, a ranging sensor includes a phase shift circuit that generates a phase-shifted drive pulse signal by shifting a drive pulse signal to a plurality of phases in a time division manner within one frame period, with the drive pulse signal being generated in response to a light emission control signal indicating an irradiation timing of a light emission source. A pixel accumulates electric charges on the basis of the phase-shifted drive pulse signal and outputs a detection signal corresponding to the accumulated electric charges, with the electric charges being obtained by photoelectrically converting reflected light by a predetermined object. The technology can be applied to a ranging module or the like that measures a distance to a predetermined object, for example.