Fingerprint Identification Device with Photosensitive Array
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Solution Overview
Problem
Conventional fingerprint identification devices require a large space due to the presence of prisms, focusing lenses, and image processors, and have a significant distance between components, making them bulky and costly.
Innovation Solution
A fingerprint identification device with intersecting gate lines and read signal lines forming fingerprint identification units, each equipped with a photosensitive element and a transistor, which generates currents based on light reflected from finger ridges and valleys, eliminating the need for prisms and image processors by using a PN junction and depletion layer to differentiate ridge and valley lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional components (prism, focusing lens, image processor) are used for fingerprint identification, then fingerprint identification function is achieved, but device thickness and occupied space increase significantly
Solution Approach 1:
The patent extracts and eliminates the prism, focusing lens, and image processor from the traditional fingerprint identification system. Instead, it uses a photosensitive element array directly coupled with a fingerprint sensor layer, removing unnecessary components while maintaining the core fingerprint identification function. This extraction principle directly resolves the contradiction by reducing device thickness without sacrificing functionality.
Solution Approach 2:
The patent replaces the mechanical/optical system (prism + focusing lens + image processor) with a direct photosensitive detection system. The photosensitive element array converts optical signals directly into electrical signals through the photoelectric effect, eliminating the need for mechanical focusing components and reducing device thickness while maintaining identification reliability.
2Reliability
If conventional components are used, then fingerprint identification is achieved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges multiple functions into a single integrated structure. The photosensitive element array serves both as the light detection component and the fingerprint sensing component, eliminating the need for separate prism, lens, and image processor components. This merging principle reduces device complexity while maintaining the fingerprint identification function.
Solution Approach 2:
The photosensitive element array performs multiple functions simultaneously: it detects reflected light, converts optical signals to electrical signals, and directly senses fingerprint patterns. This multi-functionality eliminates the need for multiple specialized components, reducing overall device complexity and component count while maintaining identification reliability.
3Manufacturing precision
If conventional components with required spacing are used, then proper light focusing is achieved, but device area and volume increase
Solution Approach 1:
The patent replaces the mechanical focusing system (lens with specific focal length requiring spacing) with a direct photosensitive detection approach. Each photosensitive element directly detects light intensity at its position, eliminating the need for optical focusing and the associated spacing requirements, thus reducing device area while maintaining detection precision.
Solution Approach 2:
The patent transitions from a three-dimensional optical path requiring spacing (prism-lens-image processor) to a two-dimensional planar array of photosensitive elements. This dimensional change allows direct light detection without requiring vertical or horizontal spacing for optical components, reducing overall device area while maintaining manufacturing precision through the array configuration.
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 reduces the thickness and cost of the device while maintaining high fingerprint identification accuracy, allowing for integration into display apparatuses without compromising aperture ratios or display effects.
Implementation Method 1
each fingerprint identification unit is provided with a photosensitive element and a first transistor. The photosensitive element includes a first electrode layer, and a first doped semiconductor layer, a second doped semiconductor layer and a second electrode layer which are sequentially positioned on a surface of the first electrode layer. An electric field is formed between the first electrode layer and the second electrode layer, and a PN junction is formed between the first doped semiconductor layer and the second doped semiconductor layer
Data Source
AI summary
A fingerprint identification device and a manufacturing method thereof, an array substrate and a display apparatus are provided. The fingerprint identification device comprises first gate lines and read signal lines. The first gate lines and the read signal lines intersect with each other to define a plurality of fingerprint identification units, and each fingerprint identification unit is provided with a photosensitive element and a first transistor. The photosensitive element includes a first electrode layer, and a first doped semiconductor layer, a second doped semiconductor layer and a second electrode layer which are sequentially positioned on a surface of the first electrode layer.