Array Substrate with Backside Fingerprint Sensors for Full-Aperture Detection
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Solution Overview
Problem
Optical fingerprint recognition sensors in display regions have limited surface area, leading to small light absorption areas and low photocurrents, causing errors in fingerprint detection and recognition due to the need for these sensors to be located in non-display regions, thereby affecting the pixel/aperture ratio.
Innovation Solution
An array substrate design with transparent display elements and auxiliary light emitting elements integrated with fingerprint recognition elements on opposite sides of a dielectric layer, allowing for larger fingerprint recognition elements and increased light absorption, while maintaining pixel aperture ratio through orthogonal projections and separate layers for insulation and reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If fingerprint recognition sensors are positioned in non-display regions, then the sensors have limited surface area and small light absorption areas, but this placement is necessary to maintain display region integrity
Solution Approach 1:
The patent positions fingerprint recognition sensors on the backside of the display panel, utilizing the z-dimension (depth) rather than consuming lateral display space. This allows the sensors to be located in a different spatial dimension, achieving both full display coverage and adequate sensor area for accurate fingerprint detection.
Solution Approach 2:
The fingerprint recognition sensors are integrated within the display panel structure itself, nested between the display layers. The sensors are embedded in the backside substrate, utilizing the existing structural space of the display panel without requiring additional external components.
2Measurement precision
If fingerprint recognition elements are made larger to increase light absorption, then the pixel/aperture ratio is affected, but larger elements improve detection accuracy
Solution Approach 1:
By moving fingerprint recognition elements to the backside of the display panel, the invention eliminates the spatial conflict between sensor size and pixel aperture ratio. The sensors can be made as large as needed on the backside without interfering with the front-side pixel structure, thereby improving photocurrent generation while maintaining display quality.
3Measurement precision
If auxiliary light emitting elements are added to provide light for fingerprint recognition, then the structure becomes more complex, but this enables improved fingerprint detection
Solution Approach 1:
The auxiliary light emitting elements serve dual functions: they provide illumination for fingerprint recognition and can also serve as display pixels when needed. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in overall device complexity while enabling improved fingerprint detection.
Solution Approach 2:
The invention merges the fingerprint recognition layer with the display structure by integrating auxiliary light emitting elements into the existing pixel units. This combination allows the same structural elements to serve both display and fingerprint recognition functions, reducing overall device complexity.
Data Source
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Figure 3A~3B
AI summary
An array substrate may include a dielectric layer(1), a plurality of pixel units(2) on the dielectric layer(1), auxiliary light emitting elements(3), and a fingerprint recognition layer(4) on a side of the dielectric layer(1) opposite from the pixel units(2). Each of the pixel units(2) may comprise transparent display elements(21). The fingerprint recognition layer(4) may comprise fingerprint recognition elements(41). The fingerprint recognition elements(41) may be configured to receive light emitted by the auxiliary light emitting elements(3) and reflected by a touch control body(10) to identify fingerprint information.