Optical Sensor Array Substrate With Wavelength Filtering for Sunlight
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Solution Overview
Problem
Optical fingerprint readers face challenges in resisting intense light, particularly in environments with ambient light disturbances such as sunlight, which affects the accuracy of fingerprint recognition.
Innovation Solution
The optical sensor array substrate and optical fingerprint reader incorporate a filter layer that transmits light within a specific wavelength range (450-500 nm) and includes a hard coating layer with a periodic laminated structure, along with an anti-fingerprint layer and electrostatic discharge units, to enhance light resistance and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the optical sensor array substrate is used in environments with intense ambient light (such as sunlight), then the fingerprint recognition system can operate in more conditions, but the accuracy of fingerprint recognition deteriorates due to light interference
Solution Approach 1:
A wavelength selection filter layer is introduced as an intermediary component between the light source and the photosensitive pixels. This filter layer selectively transmits only specific wavelength ranges (450-500nm for blue light, 600-680nm for red light) while blocking other wavelengths including intense ambient sunlight. This mediator enables the system to operate in diverse lighting conditions while maintaining recognition accuracy by preventing harmful light interference.
2Object-affected harmful factors
If a filter layer is added to the optical sensor array substrate to block intense light, then the resistance to intense light is improved, but the device structure becomes more complex
Solution Approach 1:
The wavelength selection filter layer is integrated directly onto the substrate surface, merging the filtering function with the existing substrate structure. The filter layer uses transparent resin materials with embedded wavelength-selective particles or dyes, combining the structural support function of the substrate with the optical filtering function in a single integrated component rather than separate elements.
Solution Approach 2:
The filter layer's optical parameters (transmission wavelength ranges, absorption characteristics) are specifically designed to match the photosensitive pixels' spectral response. By optimizing the filter's transmission bands to coincide with the photosensitive elements' peak sensitivity (450-500nm and 600-680nm), the system achieves effective light blocking with minimal impact on the overall structure.
3Object-affected harmful factors
If multiple layers (filter layer, hard coating layer, anti-fingerprint layer) are added to enhance light resistance and durability, then the resistance to intense light and durability are improved, but the manufacturing process becomes more complex
Solution Approach 1:
The protective structure is segmented into functionally distinct layers: the filter layer for wavelength selection, the hard coating layer for mechanical durability and scratch resistance, and the anti-fingerprint layer for surface cleanliness. Each layer can be manufactured and optimized independently using specialized processes, then sequentially assembled onto the substrate, simplifying the overall manufacturing complexity compared to attempting to achieve all functions in a single layer.
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 solution significantly improves the resistance to intense light, ensuring high accuracy in fingerprint recognition by filtering out unwanted wavelengths and providing enhanced durability and noise reduction.
Implementation Method 1
incorporate a filter layer that transmits light within a specific wavelength range (450-500 nm)
Implementation Method 2
the optical sensor is a key device for realizing fingerprint acquisition, which converts a received light signal reflected by a finger surface into an electrical signal
Implementation Method 3
a hard coating layer with a periodic laminated structure, along with an anti-fingerprint layer
Data Source
AI summary
An optical sensor array substrate and an optical fingerprint reader are provided. The optical sensor array substrate includes a substrate including a detection area which includes a plurality of photosensitive pixels. Photosensitive pixel includes: a TFT arranged on the substrate; a storage capacitor arranged on the substrate and having a first capacitor plate, and a second capacitor plate electrically connected to the source or drain of the TFT; a photosensitive element located on one side of the storage capacitor away from the substrate, and having one end electrically connected to the second capacitor plate; a first electrode layer located on one side of the photosensitive element away from the substrate and electrically connected to another end of the photosensitive element. An orthographic projection of the second capacitor plate on the substrate at least partially overlaps with an orthographic projection of the first electrode layer on the substrate.