Under-Display Proximity Sensing Without TFT Photoelectric Interference
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Solution Overview
Problem
The increasing display area in electronic devices has led to reduced space for proximity sensors, causing light generated by these sensors to interfere with thin film transistors (TFTs) in the display, resulting in unintended display malfunctions, such as unwanted light emission.
Innovation Solution
The proximity sensor is positioned under the display, and its light emitters are operated in a manner that the energy of the light generated is lower than the work function of silicon in the TFTs, minimizing photoelectric effects and preventing display malfunctions. This is achieved by adjusting the wavelength of the light emitted by the proximity sensor to ensure it does not induce unintended conductivity in the TFTs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the proximity sensor is disposed under the display to increase display area, then the display area is increased, but light generated by the proximity sensor interferes with TFTs causing display malfunction
Solution Approach 1:
The patent changes the energy parameter of the light generated by the proximity sensor to be lower than the work function of silicon in TFTs. This parameter change prevents photoelectric effects in the TFTs while allowing the proximity sensor to be disposed under the display, thus increasing display area without causing display malfunction.
Solution Approach 2:
The patent converts the potentially harmful light from the proximity sensor into a beneficial situation by ensuring the light energy is lower than the work function of silicon. This transforms what would be a harmful photoelectric effect into a safe condition where the light does not interfere with TFT operation, allowing the proximity sensor to be positioned under the display.
2Measurement precision
If light energy from proximity sensor is increased to improve sensor performance, then sensor detection capability is improved, but photoelectric effects in TFTs are triggered causing unintended light emission
Solution Approach 1:
The patent optimizes the light energy parameter within a specific range - high enough to enable effective proximity detection but strictly lower than the work function of silicon to prevent photoelectric effects. This parameter optimization achieves both improved sensor performance and prevention of harmful photoelectric effects in TFTs.
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 solution effectively prevents display malfunctions by suppressing photoelectric effects in the TFTs, ensuring reliable operation even when the proximity sensor is positioned under the display, thereby maintaining display integrity.
Implementation Method 1
light generated by the proximity sensor may have an energy lower than a work function of silicon included in the multiple TFTs of the display
Data Source
AI summary
An electronic device is provided. The electronic device includes a display including a plurality of thin film transistors (TFTs), a proximity sensor disposed under the display and including a plurality of light emitting units, and at least one processor operatively coupled to the display and the proximity sensor. The light generated from the proximity sensor may have a lower energy than the work function of silicon included in the plurality of TFTs of the display.