Fingerprint Module Light Shading Layer Design
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Solution Overview
Problem
Current fingerprint identification modules in display devices suffer from reduced detection accuracy due to the large space occupied by connecting holes for light shading components, which limits the area of photosensitive diodes and thus the light current generated during fingerprint detection.
Innovation Solution
The proposed fingerprint identification module features a light shading layer with a first light shading component connected to the photosensitive diode at the same layer as the fixed potential signal line, eliminating the need for connecting holes and maximizing the photosensitive diode area, while also incorporating a second light shading component above the control transistor to shield external light and maintain transistor performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If connecting holes are used to connect light shading components to fixed potential signal lines, then electrical connection is achieved, but the space occupied by connecting holes reduces the photosensitive diode area and limits light current generation
Solution Approach 1:
The patent merges the light shading component and fixed potential signal line into the same layer, eliminating the need for connecting holes that would penetrate between layers. This integration allows the light shading component to be directly connected to the fixed potential signal line at the same level, maximizing the photosensitive diode area while maintaining electrical connection reliability.
Solution Approach 2:
The patent transitions from a vertical connection approach (using connecting holes to reach fixed potential signal lines in lower layers) to a horizontal same-layer connection approach. By placing the light shading component and fixed potential signal line in the same layer, the electrical connection is achieved without occupying vertical space, thereby maximizing the photosensitive diode area.
2Reliability
If the photosensitive diode area is reduced to accommodate connecting holes, then electrical connection is maintained, but the light current generated during fingerprint detection is limited
Solution Approach 1:
The patent combines the light shading component and fixed potential signal line in the same layer, eliminating the need for connecting holes that would reduce the photosensitive diode area. This merging allows maximum photosensitive diode area to generate sufficient light current while maintaining stable electrical connection through same-layer integration.
Solution Approach 2:
The patent changes the connection dimension from vertical (through connecting holes) to horizontal (same layer), allowing the photosensitive diode to occupy maximum area for light current generation while electrical connection is maintained through same-layer routing of the light shading component to the fixed potential signal line.
3Reliability
If light shading component is added to shield external light, then transistor performance is improved, but device structure becomes more complex
Solution Approach 1:
The patent merges the light shading component with the fixed potential signal line in the same layer, reducing structural complexity compared to using separate connecting holes and multiple layers. This integration maintains the light shielding function to protect the transistor from external light while simplifying the overall device structure.
Solution Approach 2:
The fixed potential signal line serves dual functions: providing a stable electrical connection and acting as part of the light shading structure. By making the light shading component integral to the signal line structure in the same layer, the patent reduces the number of separate components needed, thereby reducing device complexity while maintaining transistor performance stability.
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 design enhances fingerprint detection accuracy by increasing the light current generated and reducing electrical interferences, thereby improving the overall detection performance.
Implementation Method 1
a photosensitive diode for sensing changes in light intensity resulted from fingerprint pressing
Implementation Method 2
a light shading layer above the photosensitive sensing units
Data Source
AI summary
A fingerprint identification module and a display device are disclosed. In the fingerprint identification module, a light shading layer above a photosensitive sensing unit includes a first light shading component above a photosensitive diode of the photosensitive sensing unit, and a fixed potential signal line. The first light shading component is electrically connected to a terminal of the photosensitive diode thereunder and connected to the fixed potential signal line. Since the fixed potential signal line is above the photosensitive diode, and the light shading layer is directly used to form the fixed potential signal line, connecting holes that need to occupy some space can be omitted, and the area occupied by the photosensitive diode can be maximized, thus the light current generated by the photosensitive diode during fingerprint detection can be increased so as to enhance fingerprint detection accuracy.