Photodiode Detection Device Dynamic Range Expansion
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Solution Overview
Problem
Detection devices face limitations in utilizing their full potential due to a narrower dynamic range for detecting brightness and darkness, where the second dynamic range is narrower than the first, preventing the sensor from making full use of its ability.
Innovation Solution
A detection device configuration that includes photodiodes with a reset potential higher than the reference potential, and a detection circuit that receives outputs in two distinct periods with different bias currents and potentials, allowing for signal intensity adjustment to expand the dynamic range recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single dynamic range is used for detection, then the circuit design is simple, but the sensor cannot make full use of its ability
Solution Approach 1:
The detection process is divided into multiple periods (first period and second period) with different reference potentials and reset potentials. This segmentation allows the sensor to operate in different dynamic ranges at different times, fully utilizing the sensor's capability while keeping the overall circuit design manageable through time-multiplexed operation.
Solution Approach 2:
The reference potential and reset potential are dynamically changed between different detection periods. By switching between different potential configurations, the system adapts the detection range to match the actual light intensity conditions, allowing the sensor to operate optimally across a wider range of conditions than a fixed circuit design would permit.
2Reliability
If the second dynamic range is narrower than the first dynamic range, then the circuit input constraints are satisfied, but the sensor cannot make full use of its ability
Solution Approach 1:
The reference potential and reset potential parameters are changed between different detection periods. In the first period, one set of potentials is applied, and in the second period, different potentials are applied. This parameter switching enables the system to overcome the limitation of the narrower circuit dynamic range by effectively utilizing the full sensor dynamic range through temporal multiplexing of different potential configurations.
3Adaptability or versatility
If dual-period detection with different potentials is implemented, then the sensor can make full use of its ability, but the detection device complexity increases
Solution Approach 1:
The detection is performed periodically in two distinct periods with different reference and reset potentials. This periodic switching allows the system to capture signals in different dynamic ranges, fully utilizing the sensor's capability. The periodic nature of the operation simplifies the control logic compared to continuous adjustment mechanisms, as the system simply alternates between two predefined states.
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
Enables the detection device to fully utilize its sensor capabilities by adjusting signal levels, overcoming the limitations of the narrower dynamic range and improving the detection of light intensity variations.
Implementation Method 1
a photodiode configured to detect light and is configured to generate an output corresponding to a degree of the detected light
Data Source
AI summary
According to an aspect, a detection device includes: sensors each of which includes a photodiode configured to detect light and is configured to generate an output corresponding to a degree of the detected light; and a detection circuit configured to receive the output of each sensor. The photodiode has an anode to which a reference potential is applied and a cathode to which a reset potential higher than the reference potential is applied. Each sensor is configured to generate the output corresponding to the degree of the light detected by the photodiode after the reset potential is applied to the cathode and before the reset potential is applied to the cathode again. The outputs of the sensors are received in a first period and a second period after the first period. The reference potential and the reset potential in the first period are different from those in the second period.