Sensor Device Dynamic Range Expansion via Reset Counting
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Solution Overview
Problem
Conventional sensor devices have a limited dynamic range due to the sensitivity of their optical sensors, which restricts their ability to accurately detect a wide range of light intensities, leading to inadequate performance in applications such as fingerprint and vein imaging.
Innovation Solution
The sensor device incorporates a two-dimensional array of optical sensors with a reset circuit, counter, and arithmetic operation circuit to calculate incident light based on sense signal values and reset counts, enhancing the dynamic range through a configuration that includes an AFE circuit and data processing circuit, and utilizes MOSFETs and photodiodes to expand the voltage range and improve signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional optical sensors are used in sensor devices, then the device structure remains simple, but the dynamic range is small and sensitivity is limited
Solution Approach 1:
The patent segments the sensing function by introducing a reset circuit that operates independently from the optical sensor array. The reset circuit counts the number of resets required to bring the sensor output within a measurable range, effectively dividing the dynamic range measurement into manageable segments that can be processed individually.
Solution Approach 2:
The patent introduces a reset circuit as an intermediary component between the optical sensor and the output stage. This reset circuit acts as a mediator that adjusts the sensor output by counting resets, enabling extended dynamic range measurement without directly modifying the optical sensor structure.
2Reliability
If the dynamic range of optical sensors is increased to improve sensitivity, then the ability to detect a wide range of light intensities improves, but the conventional sensor structure becomes inadequate
Solution Approach 1:
The reset circuit serves multiple functions: it resets the sensor output when it exceeds the measurable range, counts the number of resets required, and provides this count information for dynamic range calculation. This multi-functionality achieves extended dynamic range without proportionally increasing device complexity.
Solution Approach 2:
The patent changes the measurement parameter from direct sensor output voltage to the number of resets required to bring the output within range. This parameter transformation enables the system to measure light intensities across a wider dynamic range by converting an absolute measurement problem into a relative counting problem.
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 enhanced dynamic range allows for improved detection of light intensities, enabling more accurate fingerprint and vein imaging by increasing the sensitivity and resolution of the sensor device, effectively addressing the limitations of conventional systems.
Implementation Method 1
optical sensors provided in a two-dimensional array... The optical sensors detect the reflected light or transmitted light of the object. For example, the optical sensors are photodiodes
Data Source
AI summary
According to one embodiment, a sensor device comprises a sensor configured to output a sense signal, a value the sense signal changing over time based on incident light, a first reset circuit configured to set the value of the sense signal to a reset value when the value of the sense signal exceeds a threshold, a counter configured to count a first number of times of reset by the first reset circuit, and an arithmetic operation circuit configured to calculate an amount of incident light of a certain period based on the value of the sense signal, the reset value, and the first number of times of reset.