Optical Filter Assembly for Under-Display Fingerprint Sensor Visibility
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Solution Overview
Problem
In portable electronic devices, the integration of a fingerprint sensor below the display causes visibility issues and degradation of the screen, as the sensor can be visible and affect the display's reflectance, leading to a dimly displayed fingerprint sensing region.
Innovation Solution
The implementation of a filter and an organic material, including a polarizing layer and phase delay layers, is used to prevent the fingerprint sensor from being visible and to maintain screen visibility by managing light reflection and transmission, ensuring the sensor is not visible and the screen remains clear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fingerprint sensor is disposed below the display, then user authentication functionality is improved, but the fingerprint sensor becomes visible and screen visibility is degraded
Solution Approach 1:
A polarizing member and phase delay member are introduced as intermediary optical elements between the display and the fingerprint sensor. These members selectively control light transmission: they allow light from the display to pass through to the sensor while blocking reflected light from the sensor that would otherwise be visible on the screen, thus resolving the visibility conflict
Solution Approach 2:
The optical properties of light are changed by using polarizing and phase delay members to alter the polarization state and phase of light waves. This enables differential transmission: light traveling from the display to the sensor has different polarization characteristics than reflected light, allowing selective blocking of reflected light while maintaining sensor functionality
2Measurement precision
If an opening is formed through sheets at the fingerprint sensing region, then the fingerprint sensor can recognize user fingerprints, but the fingerprint sensor becomes visible to the naked eye when the screen is off
Solution Approach 1:
The polarizing member and phase delay member act as optical intermediaries positioned at the opening region. They enable the fingerprint sensor to receive light for recognition while simultaneously blocking reflected light from being visible, as the reflected light has different polarization properties that the intermediary members are designed to block
3Illumination intensity
If a polarizing member and phase delay member are added to block reflected light, then screen visibility is improved, but device complexity increases
Solution Approach 1:
The polarizing member and phase delay member are combined into a single integrated optical assembly that performs both functions simultaneously. This merging reduces the number of separate components and simplifies the overall structure while maintaining the dual functionality of enabling sensor operation and blocking reflected light
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 effectively blocks the fingerprint sensor from being visible and prevents visibility degradation of the screen, enhancing user authentication functionality while maintaining the display's clarity and functionality.
Implementation Method 1
a polarizing layer and a phase delay layer disposed below the polarizing layer
Implementation Method 2
a first phase delay member disposed, corresponding to the opening, below the display panel, to enable at least a part of light passing through the polarizing layer and the phase delay layer of the display panel and rotating circularly in a first direction, to vibrate linearly in the first direction
Implementation Method 3
a second phase delay member disposed below the polarizing member to enable at least a part of the light vibrating linearly in the first direction, the light having been transmitted through the polarizing member, to rotate circularly in a second direction
Implementation Method 4
a polarizing member disposed below the first phase delay member to enable at least a part of the light vibrating linearly in the first direction, to be transmitted therethrough
Implementation Method 5
the second phase delay member has an optical property such that at least a part of the light rotating circularly in the second direction collides with the image sensor to be reflected toward the second phase delay member, and the reflected light rotating circularly in the second direction is changed to the light vibrating linearly in the second direction different from the first direction by means of the second phase delay member so as to be blocked by the polarizing member
Data Source
AI summary
The present invention relates to a method for improving the visibility of a display and an electronic device for implementing same, the electronic device comprising: a display panel including a polarization layer and a phase delay layer; an impact absorbing member disposed below the display panel and having an opening; an image sensor disposed corresponding to the opening; a first phase delay member disposed below the display panel to correspond to the opening such that a part of the light passed through the display panel and rotating in a circular direction of a first direction vibrates linearly in the first direction; a polarizing member disposed below the first phase delay member; and a second phase delay member disposed below the polarizing member such that a part of the light transmitted through the polarizing member and vibrating linearly in the first direction may rotate in a circular direction of a second direction.