Behind Display Polarized Optical Transceiver Crosstalk Mitigation
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Solution Overview
Problem
Mobile devices experience degradation in phone call quality due to module crosstalk, where back reflections within the device overwhelm the proximity sensor, leading to erroneous signal detection and dropped calls, especially when the sensor is positioned behind the display stack.
Innovation Solution
A polarized optical transceiver system is integrated behind the display, using polarization control elements to differentiate between crosstalk signals and target signals by aligning the polarization of light with the optical axis of the display stack, reducing crosstalk and improving signal clarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the proximity sensor is positioned behind the display stack, then the device structure is more integrated and compact, but module crosstalk increases due to back reflections within the display stack elements
Solution Approach 1:
A polarization control element is introduced as an intermediary component between the light source and the display stack. This element manipulates the polarization state of light to differentiate between crosstalk signals (which maintain polarization) and target signals (which lose polarization after reflecting off the sample), thereby resolving the crosstalk issue while maintaining the integrated sensor positioning behind the display
Solution Approach 2:
The patent changes the polarization parameter of the light emitted by the light source. By controlling the polarization state and analyzing it at the receiver, the system can distinguish between light that has undergone crosstalk reflections within the display stack and light that has properly reflected off the external target, thus reducing the harmful crosstalk effect
2Measurement precision
If the sensor receives back reflections within the mobile device, then the sensor can detect internal structures, but erroneous signals are produced due to crosstalk overwhelming the target detection
Solution Approach 1:
The polarization control element acts as a mediator that filters and differentiates between crosstalk signals and target signals based on their polarization characteristics. This intermediary component enables the sensor to accurately detect target reflections while rejecting erroneous crosstalk signals, thereby improving measurement precision and preventing information loss
3Measurement precision
If polarization control elements are added to differentiate between crosstalk and target signals, then signal clarity is improved, but device complexity increases
Solution Approach 1:
The polarization control element serves multiple functions: it modifies the polarization state of emitted light, acts as a reference for polarization analysis, and enables signal differentiation. By integrating this multi-functional component, the system achieves improved signal clarity without requiring multiple separate subsystems, thus limiting the increase in overall device complexity
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
The polarized optical transceiver effectively mitigates crosstalk, enhancing the functionality of mobile devices by reducing noise interference and improving the accuracy of proximity detection, leading to fewer dropped calls and better overall performance.
Implementation Method 1
the transmitter polarization control element may change the polarization states of the light and the polarized light may propagate toward the display
Implementation Method 2
the receiver polarization control element may differentiate between the crosstalk signals and the target signal
Implementation Method 3
the polarized light may have a polarization that aligns with an orientation of the optical axis of the thin film transistor stack
Data Source
AI summary
Configurations for display stacks of an electronic device and methods for mitigating crosstalk are disclosed. The display stack may include a transceiver module, which may be located under or behind the display. The transceiver module may include a transmitter module, which may provide polarized light from the transmitter that may suppress module crosstalk. The transceiver module also may include a receiver module, which may include polarization control elements and an analyzer for differentiating between a target signal and a crosstalk signal. The polarization control on both the transmitter module and receiver module sides may suppress the crosstalk signals, which may be due to the reflections between and within the elements of the display stack and resulting from positioning the transceiver module behind the display.