Transparent Display Openings for Under-Display Sensor Light and Diffraction
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Solution Overview
Problem
Electronic devices with full-face displays face challenges in sensor performance due to low light transmission through the display stack, which is typically less than 20% in the visible spectrum, limiting the effectiveness of under-display sensors like cameras and ambient light sensors.
Innovation Solution
The implementation of non-pixel regions devoid of thin-film transistors and other display components, referred to as transparent windows, to increase light transmittance, combined with patterns of transparent windows to mitigate diffraction artifacts, and the use of black pixel definition layers and light-absorbing layers to reduce back emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the display covers the entire front face with full pixel density, then the display area is maximized, but light transmission to under-display sensors becomes insufficient
Solution Approach 1:
The display is segmented into two distinct regions: a first region with full pixel density for display purposes, and a second region with reduced or removed pixels (transparent windows) for sensor light transmission. This segmentation allows each region to fulfill its specific function optimally while maintaining overall display coverage.
Solution Approach 2:
Different regions of the display are assigned different optical properties: the first region maintains high pixel density for visual output, while the second region features reduced pixel density or transparent windows to maximize light transmission to underlying sensors. This local differentiation resolves the contradiction between display area and sensor illumination.
2Illumination intensity
If transparent windows are introduced to increase light transmission, then sensor performance improves, but diffraction artifacts are introduced
Solution Approach 1:
The transparent windows in the second region are designed with asymmetric or non-uniform patterns rather than regular grids. This asymmetry disrupts the periodic structure that causes diffraction artifacts, while still maintaining sufficient light transmission pathways to the sensor.
Solution Approach 2:
The transparent windows may employ curved or rounded geometries rather than sharp rectangular edges. This curvature reduces diffraction effects by eliminating sharp boundaries that cause light wave interference, thereby minimizing artifacts while preserving light transmission.
3Illumination intensity
If pixel density is reduced in the second region, then light transmission increases, but display resolution decreases
Solution Approach 1:
The display is divided into functional zones where the first region maintains high pixel density for resolution-critical areas, while the second region accepts reduced pixel density in exchange for enhanced sensor light transmission. This spatial segmentation allows resolution requirements to be met in display areas without compromising sensor performance.
Solution Approach 2:
The second region with reduced pixel density serves multiple functions: it provides light transmission pathways for sensors while still maintaining basic display functionality. This multi-functionality allows the same structure to address both display and sensing requirements simultaneously.
4Ease of manufacture
If standard display components are used throughout, then manufacturing is simplified, but sensor performance is limited due to low light transmission
Solution Approach 1:
The display structure is segmented into a first region with standard components for ease of manufacture and a second region with modified components (reduced pixels, transparent windows) optimized for sensor performance. This segmentation allows the majority of the display to use cost-effective standard manufacturing while specific regions are tailored for sensor functionality.
Solution Approach 2:
Standard display components are used in the first region where display quality is paramount, while the second region employs locally optimized structures with reduced pixel density or transparent windows. This local differentiation balances manufacturing complexity with sensor performance 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
Enhances light transmission to under-display sensors, improving their performance by increasing the transparency of the display to over 25% and reducing diffraction artifacts, thereby enhancing the functionality of sensors like cameras and ambient light sensors.
Implementation Method 1
The plurality of non-pixel regions is configured to increase the transmittance of light through the display to the sensor
Implementation Method 2
Light passing through the transparent windows may have associated diffraction artifacts based on the pattern of the transparent windows
Implementation Method 3
the display may include a black pixel definition layer. Additionally light absorbing layers may be coated on metal layers in the thin-film transistor layer of the display to mitigate back emission
Data Source
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AI summary
An electronic device may include a display and an optical sensor formed underneath the display. The electronic device may include a plurality of transparent windows that overlap the optical sensor. The resolution of the display panel may be reduced in some areas due to the presence of the transparent windows. To mitigate diffraction artifacts, a first sensor (13-1) may sense light through a first pixel removal region having transparent windows arranged according to a first pattern. A second sensor (13-2) may sense light through a second pixel removal region having transparent windows arranged according to a second pattern that is different than the first pattern. The first and second patterns of the transparent windows may result in the first and second sensors having different diffraction artifacts. Therefore, an image from the first sensor may be corrected for diffraction artifacts based on an image from the second sensor.