Optical Detection Circuit Using Photosensitive Transistor Threshold Voltage
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Solution Overview
Problem
Current optical detection circuits lack efficiency in detecting optical signals within specific wavelength ranges, failing to provide a concise and convenient method for signal detection in various applications.
Innovation Solution
An optical detection circuit comprising a photosensitive transistor, a resetting unit, an energy storing unit, and a detection control unit, where the threshold voltage of the photosensitive transistor changes with the intensity of the optical signal, allowing for detection of the signal's intensity based on an electric signal obtained from the energy storing unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional optical detection circuits are used, then optical signals can be detected, but the detection efficiency and convenience for specific wavelength ranges is insufficient
Solution Approach 1:
The patent changes the operating parameters of the photosensitive transistor by applying different voltages to the gate electrode at different stages (resetting stage with first voltage, detection stage with second voltage). This parameter change enables the transistor to operate optimally for specific wavelength ranges while maintaining high detection efficiency and convenience
Solution Approach 2:
The patent implements a preliminary resetting action before detection by applying a first voltage to the gate electrode to initialize the photosensitive transistor state. This preliminary action ensures the transistor is properly prepared for subsequent optical signal detection, improving both efficiency and convenience
2Measurement precision
If the threshold voltage of the photosensitive transistor changes with optical signal intensity, then photoelectric conversion efficiency improves, but circuit control complexity increases
Solution Approach 1:
The patent dynamically adjusts the gate electrode voltage between two discrete levels (first voltage during resetting, second voltage during detection) based on the operational stage. This dynamic control exploits the threshold voltage change with optical intensity while maintaining manageable circuit complexity through standardized switching control
Solution Approach 2:
The patent employs periodic switching between resetting and detection stages, with each stage having a specific voltage applied to the gate electrode. This periodic action synchronizes with the optical signal detection cycle, enabling precise intensity measurement while simplifying control through rhythmic voltage switching
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 efficient detection of optical signal intensity by utilizing the changing threshold voltage of the photosensitive transistor, effectively achieving photoelectric conversion and suitable for applications in medical instruments, cellular phones, and security systems.
Implementation Method 1
a threshold voltage of the photosensitive transistor changes as an intensity of an optical signal received by the photosensitive transistor changes
Data Source
AI summary
An optical detection circuit, an optical detection method and an optical detection device are provided. The circuit includes a photosensitive transistor, a resetting unit, an energy storing unit, a detection control unit and a detection unit. A threshold voltage of the photosensitive transistor varies with an intensity of an optical signal received by the photosensitive transistor. A wavelength of the optical signal is within a preset wavelength range. The detection control unit is configured to control the first node to be connected to the detection unit under control of a detection control terminal. The detection unit is connected to the first node via the detection control unit and is configured to, when the detection control unit controls the first node to be connected to the detection unit, detect an electric signal from the first node and obtain the intensity of the optical signal based on the electric signal.