Optical Fingerprint Sensor Layout for Lower-Cost In-Display Sensing
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Solution Overview
Problem
The integration of fingerprint sensors into display devices increases production costs due to the use of photo sensors throughout the display panel, which can be costly and inefficient.
Innovation Solution
Incorporating an optical sensing fingerprint sensor where photo sensors are strategically placed within the display panel, overlapping with or between pixels, and utilizing a pinhole array layer to reduce thickness and production costs, while maintaining fingerprint sensing functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photo sensors are used throughout the display panel to provide fingerprint sensing function, then fingerprint detection capability is improved, but production cost increases
Solution Approach 1:
The display panel is divided into a display area and a non-display area, with photo sensors strategically placed only in the non-display area rather than throughout the entire panel. This segmentation allows fingerprint sensing functionality to be achieved while reducing the total number of photo sensors required, thereby lowering production costs while maintaining detection capability.
Solution Approach 2:
The pixels in the display area serve dual purposes: they function as display elements and simultaneously act as light sources for the fingerprint sensor. This multi-functionality eliminates the need for separate light sources and reduces the overall component count, addressing both the fingerprint detection requirement and cost reduction goal.
2Reliability
If photo sensors are placed throughout the display panel to ensure comprehensive fingerprint sensing, then sensing coverage is improved, but device thickness increases
Solution Approach 1:
The sensor layer is configured with photo sensors only in the non-display area, separating the display function from the sensing function spatially. This allows the display panel to maintain its display quality while incorporating fingerprint sensing capability with reduced thickness, as photo sensors are not placed throughout the entire panel area.
3Measurement precision
If separate light sources are added to the fingerprint sensor to improve detection accuracy, then fingerprint sensing precision is improved, but device complexity and production cost increase
Solution Approach 1:
The pixels in the display area are utilized as light sources for the fingerprint sensor, eliminating the need for separate dedicated light sources. This multi-functional approach maintains fingerprint sensing precision while reducing device complexity and production cost by repurposing existing display components.
Solution Approach 2:
The display pixels serve their primary display function while simultaneously providing the light source function for fingerprint sensing. This self-service approach allows the system to achieve dual functionality without adding external components, thereby reducing complexity while maintaining sensing precision.
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 configuration reduces production costs and thickness by using pixels as light sources for the fingerprint sensor, allowing for effective fingerprint detection without the need for separate light sources, thereby enhancing security and reducing costs.
Implementation Method 1
a light source and at least one photo sensor
Implementation Method 2
The optical sensing fingerprint sensor includes a light source and at least one photo sensor
Data Source
Figure 1~2
Figure 3A~3B
Figure 3C~3D
AI summary
A fingerprint sensor includes: a pixel layer including a plurality of pixels (PXL); a light transmitting hole array layer (PHL) including a plurality of light transmitting holes (PIH) providing light transmitting paths of light rays that are incident through the pixel layer; and a sensor layer (120) including a plurality of photo sensors (PHS) configured to sense the light rays that pass through the light transmitting holes (PIH) and are incident on the sensor layer (120). A resolution at which the photo sensors (PHS) are disposed in first areas (A1) on the sensor layer (120) differs from a resolution at which the photo sensors (PHS) are disposed in second areas (A2) on the sensor layer.