OLED Display Optical Fingerprint Sensor Air Gap Spacer Design
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Solution Overview
Problem
Conventional fingerprint recognition systems face challenges in integrating a fingerprint sensor into larger display units due to space constraints, as the size of display units increases and buttons are minimized, making it difficult to secure space for a separate fingerprint recognition unit.
Innovation Solution
Incorporating a fingerprint sensor directly onto the display unit, specifically using an optical fingerprint sensor on the back surface of an organic light emitting diode (OLED) display, which allows light to pass through and enables fingerprint recognition without the need for additional space, and employing spacers to maintain a consistent air gap and prevent the Moire effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a separate fingerprint recognition unit is used, then fingerprint recognition function is achieved, but device size increases and display area is reduced
Solution Approach 1:
The patent combines the fingerprint sensor with the display unit by positioning the sensor beneath the display panel at the finger placement area, allowing the display unit to serve dual purposes as both display and fingerprint recognition interface, thereby eliminating the need for separate fingerprint recognition units and maximizing display area
Solution Approach 2:
The display unit is designed to perform multiple functions: it serves as both the visual display interface and the fingerprint recognition interface by integrating the fingerprint sensor beneath the display panel at the touch area, allowing a single component to fulfill multiple roles
2Area of stationary object
If fingerprint sensor is integrated into display unit, then space is saved, but image quality may be distorted due to Moire effect
Solution Approach 1:
The patent introduces an optical compensation film positioned between the fingerprint sensor and the display panel to compensate for optical distortions and prevent the Moire effect, ensuring that the integrated design does not compromise image quality
Solution Approach 2:
The patent adjusts optical parameters by introducing the compensation film with specific optical properties that modify light transmission characteristics, thereby eliminating Moire patterns and maintaining image quality in the integrated display-sensor structure
3Measurement precision
If air gap between sensor and display is reduced, then recognition accuracy improves, but optical distortion increases
Solution Approach 1:
The optical compensation film serves as an intermediary element that allows the maintenance of an optimized air gap distance for fingerprint recognition accuracy while simultaneously compensating for optical distortions, balancing both requirements
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 solution allows for high recognition rates of fingerprints by ensuring the sensor is integrated seamlessly with the display unit, preventing distortion and maintaining image quality while addressing space constraints and recognition accuracy issues.
Implementation Method 1
an optical fingerprint sensor on the back surface of an organic light emitting diode (OLED) display, which allows light to pass through
Implementation Method 2
employing spacers to maintain a consistent air gap and prevent the Moire effect
Data Source
Figure 1A
Figure 1B~1C
Figure 2(a)~2(b)
AI summary
Disclosed herein is a display device including a display unit, a cover glass protecting the display unit, an optical layer disposed on a back surface of the display unit to form a first air gap, an optical sensor disposed on a back surface of the optical layer to form a second air gap, the optical sensor being mounted on the base substrate, a first spacer positioned between the optical layer and the display unit and arranged around the first air gap, a first sealant applied in a paste state and changed into a hard state to bond the first spacer and the display unit, a second spacer positioned between the optical sensor and the optical layer and arranged around the second air gap, anda controller configured to determine whether information collected by the optical sensor matches the fingerprint information about the user stored in a memory unit.