Sensor Depth Measurement Using Dynamic Window Time and Charge Overflow Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current light sensors face challenges in accurately measuring the depth of objects within a specific range, particularly in distinguishing between objects within and outside the measuring range, leading to measurement errors and unwanted detection of distant or close objects.
Innovation Solution
The proposed solution involves a sensor system with a pixel array, converting circuit, and driving circuit that generate and manage photo gate signals and overflow control signals to selectively sense light within a defined window time, allowing for precise depth measurement by adjusting the delay and window times based on the selected measuring range, and using an overflow transistor to remove charges outside the measuring range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light sensor continuously senses all reflected light, then it can detect all objects in the field of view, but it cannot distinguish between objects within and outside the measuring range, leading to measurement errors
Solution Approach 1:
The sensing time is segmented into multiple distinct periods: delay time, window time, and masking time. By dividing the continuous sensing period into discrete segments with specific functions, the sensor can selectively process light from different time intervals, enabling it to distinguish objects within the measuring range from those outside it.
Solution Approach 2:
The sensor performs preliminary actions by clearing charges generated during the delay time before the actual measurement window. This preliminary clearing action prevents charges from out-of-range objects from interfering with the depth measurement, ensuring that only charges from the target range are measured.
2Adaptability or versatility
If the sensor uses a fixed sensing time window, then it can maintain simple circuit operation, but it cannot adapt to different measuring ranges and object distances
Solution Approach 1:
The sensor employs dynamic control of the sensing window by adjusting the delay time and window time based on the selected measuring range. The driving circuit generates different photo gate signals dynamically, allowing the sensing system to adapt to various object distances and measuring ranges while maintaining a relatively simple pixel structure.
3Reliability
If the sensor removes all charges outside the window time, then it eliminates interference from out-of-range objects, but it may also remove valid charges from legitimate targets
Solution Approach 1:
The overflow transistor is configured to remove charges selectively based on their generation time. By controlling the overflow transistor to operate only during specific time periods (delay time and masking time), the system achieves local quality differentiation, removing harmful charges from out-of-range objects while preserving valid charges from in-range targets.
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 enhances the accuracy of depth measurement by ensuring that only objects within the specified range are sensed, reducing errors and improving the system's ability to differentiate between objects at close and distant distances.
Implementation Method 1
a photoelectric conversion element configured to generate charges based on the reflected pulses
Data Source
AI summary
According to at least some example embodiments of the inventive concepts, a sensor includes a pixel array including a pixel configured to generate a first pixel signal and a second pixel signal, based on a light sensed during a window time of a sensing time; processing circuitry configured to select a measuring range from among a plurality of measuring ranges and set a width of the window time based on the selected measuring range; a converting circuit configured to convert the first and second pixel signals into digital signals; and a driving circuit configured to generate an overflow control signal, a first photo gate signal, and a second photo gate signal so as to sense the light during the window time, wherein the pixel includes, a photoelectric conversion element, first and second readout circuits configured to receive charges, and an overflow transistor configured to remove charges.