Offset-Gate Light Sensor Layout for Residual Charge Reset
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Solution Overview
Problem
Residual charges in photoelectric sensors can affect the accuracy of light sensing, as they are not effectively eliminated after converting light into electrical signals, impacting subsequent sensing cycles.
Innovation Solution
A light sensing device is designed with a reset electrode that contacts the semiconductor layer, allowing for the removal of residual charges, and can also function as a switch device, with a gate electrode controlling part of the channel to achieve simultaneous light sensing and switching capabilities. The device is integrated with display panels, enabling manufacturing alongside pixel electrodes to save masks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a photoelectric sensor converts light into electrical signals, then light sensing capability is achieved, but residual charges remain in the sensor affecting subsequent sensing cycles
Solution Approach 1:
The patent extracts the harmful residual charges from the semiconductor layer by introducing a reset electrode that contacts the semiconductor layer. This reset electrode provides a dedicated path to remove accumulated charges, thereby eliminating the adverse effect on subsequent sensing cycles while preserving the light sensing capability.
Solution Approach 2:
The patent applies preliminary action by using the reset electrode to clear residual charges before the next sensing cycle begins. This preliminary charge removal ensures that each sensing cycle starts with a clean state, improving both sensing accuracy and consistency across multiple cycles.
2Measurement precision
If a reset electrode is added to remove residual charges, then sensing accuracy is improved, but device complexity increases
Solution Approach 1:
The gate electrode is designed to perform multiple functions: it controls the channel for light sensing operation and also serves as the reset electrode to remove residual charges. By making the gate electrode multi-functional, the patent improves sensing accuracy without adding extra structural elements, thus avoiding increased device complexity.
3Adaptability or versatility
If the gate electrode controls part of the channel, then switching capability is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by having the gate electrode control only a portion of the semiconductor layer channel rather than the entire channel. This partial control approach enables switching capability while being more tolerant to manufacturing variations, as the gate does not require perfect alignment with the entire channel length, thus reducing manufacturing precision requirements.
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 reset electrode improves sensing accuracy and sensitivity by eliminating residual charges, while the gate-controlled channel enables dual functionality in light sensing and switching, enhancing the performance of light sensing display panels.
Implementation Method 1
Photoelectric sensors can convert light into current or voltage signals. The photoelectric sensor may include a semiconductor thin film having a suitable band gap corresponding to the wavelength of light to be absorbed.
Data Source
AI summary
A light sensing device includes a substrate, a gate electrode, a semiconductor layer, a dielectric layer, a first source/drain electrode, a second source/drain electrode, and a reset electrode. The gate electrode is over the substrate. The semiconductor layer is over the substrate and at least partially overlapping the gate electrode. The dielectric layer spaces the gate electrode from the semiconductor layer. The first source/drain electrode and the second source/drain electrode are respectively connected to the semiconductor layer. The semiconductor layer has a first region and a second region between the first source/drain electrode and the second source/drain electrode, the first region overlaps the gate electrode, and the second region does not overlap the gate electrode. The reset electrode is in contact with the semiconductor layer.