Inclined Optical Sensor Module for Accurate Fingerprint Detection
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Solution Overview
Problem
Conventional on-display fingerprint sensing using optical sensors often experiences partial or inaccurate detection due to light being redirected by layers in the display panel, leading to unreliable fingerprint recognition.
Innovation Solution
The electronic device incorporates an optical sensor module positioned at an inclination angle relative to the cover layer's axis, overlapping with the fingerprint sensing area, and utilizing a prism layer and diffuser layer to optimize light capture, ensuring accurate and reliable fingerprint detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an optical sensor is positioned directly below the fingerprint sensing area in a conventional on-display configuration, then the device structure is simple and compact, but light is redirected by display panel layers causing partial or inaccurate fingerprint detection
Solution Approach 1:
The optical sensor module is positioned at an inclined angle (e.g., 45 degrees) relative to the display panel surface rather than directly below the fingerprint sensing area. This dimensional change in sensor orientation allows light to reach the sensor after passing through the display layers without being redirected, thereby improving fingerprint detection accuracy while maintaining a relatively compact device structure.
2Reliability
If the optical sensor module is positioned at an inclination angle to improve light capture, then fingerprint sensing accuracy is improved, but the alignment and positioning complexity increases
Solution Approach 1:
The optical sensor module is pre-positioned at a specific inclination angle (e.g., 45 degrees) during the display panel manufacturing process. This preliminary positioning ensures that the sensor is correctly aligned before final assembly, simplifying the manufacturing process and reducing the need for complex post-assembly alignment procedures while maintaining high fingerprint sensing reliability.
3Productivity
If the optical sensor module overlaps with the fingerprint sensing area, then light capture efficiency is improved, but the device thickness increases
Solution Approach 1:
The optical sensor module is positioned at an inclination angle relative to the display panel surface, allowing it to overlap with the fingerprint sensing area in the planar dimension while maintaining a compact thickness profile. This angular positioning enables efficient light capture without significantly increasing the overall device thickness, as the sensor extends diagonally rather than perpendicular to the display surface.
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 enhances the capture of fingerprint information, resulting in improved reliability and performance of the optical sensor module, providing faster and more accurate fingerprint sensing.
Implementation Method 1
one or more light sources configured to produce an illuminating light that passes through the LCD panel to illuminate the predetermined fingerprint sensing area
Implementation Method 2
an optical sensor module for receiving a light from the predetermined fingerprint sensing area to detect the fingerprint
Implementation Method 3
an optical sensor module for receiving a light from the predetermined fingerprint sensing area to detect the fingerprint
Data Source
AI summary
An electronic device (200) includes a liquid crystal display (LCD) panel (204), a cover layer (218), one or more light sources (224), and an optical sensor module (226). The LCD panel (204) receives a contact input associated with a fingerprint of a user. The cover layer (218) includes a first major surface (228) and a second major surface (230) opposite to the first major surface (228), and is disposed on the LCD panel (204). The cover layer (218) defines a first axis (AA′) normal to the first major surface (228). The optical sensor module (226) receives a light from the predetermined fingerprint sensing area (222) to detect the fingerprint. The optical sensor module (226) at least partially overlaps with the predetermined fingerprint sensing area (222) along the plane of the first major surface (228). The optical sensor module (226) defines a second axis (BB′) normal to a surface of the optical sensor module (226). The second axis (BB′) is inclined at an inclination angle relative to the first axis (AA′) of the cover layer (218).