OLED Fingerprint Sensor Collimator Filter Layer
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Solution Overview
Problem
Fingerprint recognition accuracy is reduced due to the distance between the finger and the fingerprint recognition device, which is exacerbated by components like cover glass, leading to increased production costs and defective rates.
Innovation Solution
A fingerprint recognition device with crisscrossed scanning and signal reading lines, incorporating a photosensitive element with a collimator filter layer that ensures incident light is irradiated parallel onto the photoelectric conversion layer, improving light transmission and reducing scattering, even with increased distance from the finger.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cover glass is provided between the finger and the fingerprint recognition device, then the display device structure is complete and protected, but the recognition accuracy is reduced due to increased distance
Solution Approach 1:
The patent introduces a light guide layer as an intermediary component between the cover glass and the photosensitive element. This light guide layer guides and concentrates the light that passes through the cover glass, ensuring that the light can still effectively reach the photosensitive element despite the increased distance, thereby maintaining recognition accuracy while preserving the protective cover glass structure
Solution Approach 2:
The patent changes the optical parameters of the system by introducing a light guide layer with specific refractive index and optical properties. This parameter change allows the light to be effectively guided and concentrated over the increased distance, compensating for the distance effect without requiring direct contact between finger and sensor
2Measurement precision
If a touch hole is formed on the cover glass to improve recognition accuracy, then the finger can contact the fingerprint recognition device directly, but the production cost increases and defective rate rises due to additional cutting processes
Solution Approach 1:
The patent extracts the light guide function from the traditional touch hole structure and implements it as a separate light guide layer. This eliminates the need for cutting holes in the cover glass, as the light guide layer can be deposited as a continuous film that selectively guides light to the sensor regions, simplifying the manufacturing process while maintaining recognition accuracy
Solution Approach 2:
The patent replaces the mechanical cutting process (forming touch holes) with a deposition process (forming light guide layer). Instead of mechanically removing material to create light paths, the light guide layer is deposited to create optical pathways, substituting a complex mechanical process with a simpler coating process that reduces cost and defects
3Strength
If the distance from the finger to the fingerprint recognition device is increased, then the cover glass can be positioned for protection and display, but the light transmission probability decreases and recognition accuracy is reduced
Solution Approach 1:
The light guide layer acts as an intermediary that bridges the gap created by the cover glass. It captures the scattered light from the finger and redirects it toward the photosensitive element, maintaining high light transmission probability despite the increased distance, thus preserving recognition accuracy while allowing the cover glass to remain in place
Solution Approach 2:
The patent modifies the optical parameters of the light transmission path by introducing the light guide layer with optimized optical properties. This changes the light propagation characteristics, increasing the light transmission probability over the increased distance and maintaining recognition accuracy
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
Enhances fingerprint recognition accuracy by increasing the probability of light transmission to the photoelectric conversion layer, eliminating the need for a touch hole in the cover glass, thus simplifying manufacturing and reducing production costs.
Implementation Method 1
The collimator filter layer is used for making incident light irradiate onto the photoelectric conversion layer in parallel
Implementation Method 2
The photoelectric conversion layer is used for performing photoelectric conversion on the incident light
Data Source
AI summary
A fingerprint recognition device and an OLED display device, which relate to the technical field of display and can solve the problems of a low recognition accuracy due to a large distance from a finger to a fingerprint recognition device. The fingerprint recognition device comprises recognition units alternately defined by a plurality of scanning lines and signal reading lines which are crisscrossed with each other. Each recognition unit is provided with a switching transistor and a photosensitive element. The photosensitive element comprises a photoelectric conversion layer and a collimator filter layer which are stacked successively. The collimator filter layer is used for irradiating incident light onto the photoelectric conversion layer in parallel, and the photoelectric conversion layer is used for performing photoelectric conversion on the incident light.