Under-Display Infrared Noise-Floor Calibration for Object Detection
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Solution Overview
Problem
Infrared sensors under display screens face challenges in accurately distinguishing background noise from useful signals due to structural deformations caused by thermal expansion and cold contraction, leading to inaccurate object detection.
Innovation Solution
The electronic device employs a transmitter and receiver positioned on the non-display side of the screen to transmit and receive optical signals with varying transmittance, allowing for calibration of background noise using a calibration coefficient determined by a processor, thereby reducing the impact of structural deformations on noise accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the infrared receiving chip is placed under the display screen to enable face reflection detection, then the device can detect approaching objects, but the background noise becomes stronger than the useful signal due to low transmittance of the display screen
Solution Approach 1:
The patent performs background noise calibration in advance by measuring the background noise when no object is approaching and storing it as reference data. This preliminary action allows the system to later compare actual signals against the pre-established baseline, effectively separating useful signals from background noise even when the background noise level is high.
Solution Approach 2:
The system continuously monitors the infrared signals and compares them against the calibrated background noise reference. When a signal exceeds the calibrated threshold by a predetermined margin, the system triggers an object detection event. This feedback mechanism enables reliable detection despite the low signal-to-noise ratio caused by the display screen's low transmittance.
2Ease of manufacture
If the structure is designed with glue for assembly, then the device can be manufactured, but thermal expansion and cold contraction cause gap changes and structural deformation leading to uncontrollable background noise variations
Solution Approach 1:
The patent performs background noise calibration at different temperature conditions in advance and stores multiple reference profiles. When the device operates, it selects the appropriate calibration profile based on current temperature conditions, thereby compensating for thermal expansion and contraction effects that cause structural deformation and background noise variations.
Solution Approach 2:
The system changes the calibration parameters by storing multiple background noise reference profiles corresponding to different temperature conditions. This allows the system to adapt to thermal expansion and cold contraction by selecting the appropriate reference profile, thereby maintaining reliable object detection despite structural deformations caused by temperature variations.
3Manufacturing precision
If calibration is performed to compensate for manufacturing inconsistencies, then batch consistency can be improved, but calibration cannot compensate for dynamic structural deformation during operation
Solution Approach 1:
The system performs preliminary calibration to establish baseline background noise characteristics for manufacturing consistency. Additionally, it implements runtime calibration by continuously monitoring when no object is present and updating the background reference, allowing it to adapt to dynamic structural deformations that occur during operation due to thermal effects or other environmental factors.
Solution Approach 2:
The patent implements a feedback mechanism that continuously monitors the infrared signals and dynamically adjusts the background noise reference during operation. When the system detects that no object is approaching, it uses this period to update the background reference profile, thereby compensating for dynamic structural deformations and maintaining accurate object detection despite changes in the physical structure over time.
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 approach enhances the accuracy of background noise calibration, enabling precise determination of object proximity by compensating for structural changes and improving overall detection reliability.
Implementation Method 1
the transmitter is configured to transmit the first optical signal and the second optical signal to the display screen, and the transmittance of the first optical signal passing through the display screen is greater than that of the second optical signal passing through the display screen
Data Source
Figure 1~2
AI summary
The present invention provides an electronic device and a noise floor calibration method. The electronic device comprises a display screen, and further comprises: a transmitter disposed on the non-display side of the display screen, and used for emitting a first optical signal and a second optical signal to the display screen, the transmittance of the first optical signal through the display screen being greater than the transmittance of the second optical signal through the display screen; a receiver disposed on the non-display side of the display screen, and used for receiving the first optical signal and the second optical signal; and a processor connected to the receiver, and used for determining a calibration coefficient according to the second optical signal received by the receiver and second reference noise floor, and determining calibrated first reference noise floor according to the calibration coefficient and the first reference noise floor, the first reference noise floor being a theoretical value of the first optical signal received by the receiver when no object is close to the display screen, and the second reference noise floor being a theoretical value of the second optical signal received by the receiver when no object is close to the display screen.