Light Shielding Layer for Display Sensor Leakage Current
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Solution Overview
Problem
External light entering a display device can deteriorate the performance of detection modules, such as fingerprint detection modules, by increasing leakage current and potentially affecting the driving performance of transistors in the sensor driving circuit.
Innovation Solution
Incorporating a light shielding layer in the sensor unit of the display device, which blocks external light from entering the sensor driving circuit and applies a light blocking voltage to prevent increased potential differences between electrodes due to hysteresis phenomena.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a light shielding layer is added to block external light, then detection module performance is improved, but device complexity increases
Solution Approach 1:
The light shielding layer is integrated within the existing sensor unit structure, nested between the substrate and the sensor driving circuit. This nesting approach allows the light shielding function to be incorporated without adding external components, thereby improving detection performance while minimizing increases in device complexity.
Solution Approach 2:
The light shielding layer serves multiple functions: it blocks external light from entering the sensor driving circuit, reduces leakage current in transistors, and prevents hysteresis phenomena. By combining these functions into a single component, the patent improves detection module performance without proportionally increasing device complexity.
2Measurement precision
If a light shielding layer is added to block external light, then sensing performance is improved, but manufacturing complexity increases
Solution Approach 1:
The light shielding layer's electrical parameter (voltage) is dynamically adjusted based on operating conditions. By changing the voltage applied to the light shielding layer, the device optimizes sensing performance while using a standard manufacturing process for the layer itself, thus improving performance without significantly increasing manufacturing complexity.
Solution Approach 2:
The light shielding layer is formed as part of the existing sensor unit fabrication process, nested within the established manufacturing workflow. This integration allows the light shielding function to be added without requiring separate manufacturing steps, thereby improving sensing performance while maintaining ease of manufacture.
3Reliability
If light blocking voltage is applied to the light shielding layer, then transistor leakage current is reduced, but energy consumption increases
Solution Approach 1:
The voltage applied to the light shielding layer is dynamically adjusted based on operating conditions. By optimizing the voltage level, the patent achieves effective suppression of transistor leakage current while minimizing the energy required to maintain the light blocking function.
Solution Approach 2:
The light blocking voltage is applied periodically or only when needed, rather than continuously. This periodic application reduces the average energy consumption while still effectively preventing leakage current when external light is present, thus improving reliability without proportionally increasing energy consumption.
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 implementation of a light shielding layer and light blocking voltage effectively prevents the deterioration of detection module performance caused by external light, thereby enhancing the sensing performance and overall reliability of the detection module.
Implementation Method 1
a light shielding layer to block an external light from entering the sensor driving circuit
Implementation Method 2
by applying the light blocking voltage to the light shielding layer, it is possible to prevent the potential difference between the control electrode and the input electrode of the transistor from being increased to a certain level or higher due to a hysteresis phenomenon
Data Source
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AI summary
According to one aspect of the invention, a detection module for a display device, the detection module includes: a substrate; a detector disposed on the substrate to detect an external signal; a sensor driving circuit disposed on the substrate to drive the detector; and a light shielding layer to block an external light from entering the sensor driving circuit and to receive a light blocking voltage.