Dual Photosensor Light Detection for Mobile Terminals
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Solution Overview
Problem
The decreasing non-display area on mobile devices makes it difficult to design and stack light sensors effectively, and ambient light sensors (ALS) near OLED/LCD panels suffer from noise interference due to direct or indirect light leakage, leading to low detection accuracy.
Innovation Solution
A device comprising a controller and two photosensitive sensors spaced apart in the same illumination environment, where the controller calculates light intensity by comparing illumination parameters between the sensors, with a light passage guiding external light to the first sensor and a light shading frame separating the sensors to prevent interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the light sensor is stacked on the mobile terminal with increasing screen-to-body ratio, then the non-display area decreases, but it becomes difficult to stack and design light sensors
Solution Approach 1:
The patent transitions from a single-point light sensor design to a two-point spatial arrangement. By positioning the first photosensitive sensor at the front surface and the second photosensitive sensor at the rear surface of the display assembly, the solution utilizes the depth dimension of the device structure. This dimensional transition allows both sensors to coexist within the constrained non-display area while maintaining their functional independence, thereby resolving the stacking design difficulty.
Solution Approach 2:
The patent divides the light detection function into two separate sensor components: a first photosensitive sensor for detecting external beam light intensity and a second photosensitive sensor for detecting ambient light. This segmentation allows each sensor to be optimized for its specific function while physically separated to avoid mutual interference, solving the design complexity issue in the constrained space.
2Area of moving object
If the ambient light sensor approaches the light emitting panel, then the screen-to-body ratio increases, but light leakage from the panel illuminates the sensor causing large noise floor and low detection accuracy
Solution Approach 1:
The patent extracts the ambient light detection function from the vicinity of the light emitting panel by positioning the second photosensitive sensor at the rear surface of the display assembly. This spatial extraction removes the sensor from the harmful light leakage environment, eliminating the noise floor issue while preserving the ability to detect ambient light intensity for display brightness control.
Solution Approach 2:
The patent introduces a light-shading structure as an intermediary element between the light emitting panel and the photosensitive sensors. This intermediary blocks the direct light leakage path from the panel to the sensors, preventing contamination of the detection signal while allowing the sensors to accurately measure ambient light conditions.
3Device complexity
If a single light sensor is used, then the device complexity is low, but the detection accuracy is insufficient due to noise interference
Solution Approach 1:
The patent merges two photosensitive sensors into a unified detection system where both sensors work together to achieve accurate light intensity measurement. The first sensor detects external beam light while the second sensor detects ambient light, and their combined information allows the system to calculate accurate light intensity by compensating for noise and interference, thereby improving precision without excessive complexity.
Solution Approach 2:
The patent implements a feedback mechanism where the controller continuously monitors the signals from both photosensitive sensors and adjusts the light intensity calculation accordingly. By using the second sensor's ambient light detection as a reference and compensation signal, the system feedback-corrects the measurements from the first sensor, eliminating noise floor effects and improving detection accuracy.
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 configuration enhances light intensity detection accuracy by isolating the second sensor from external light and using it as a reference to eliminate noise, allowing for precise ambient light sensing and dynamic display brightness adjustment.
Implementation Method 1
a first photosensitive sensor and a second photosensitive sensor which are electrically coupled to the controller, the first photosensitive sensor and the second photosensitive sensor being spaced apart and located in a same illumination environment, and the controller is configured to, when an external beam illuminates the first photosensitive sensor
Implementation Method 2
the display screen layer being provided with a light passage for guiding incidence of an external beam
Data Source
AI summary
A device for detecting light intensity, a display screen and a mobile terminal are provided. The device for detecting light intensity includes a controller, and a first photosensitive sensor and a second photosensitive sensor which are electrically coupled to the controller, the first photosensitive sensor and the second photosensitive sensor being spaced apart and located in a same illumination environment, and the controller is configured to, when an external beam illuminates the first photosensitive sensor, perform calculation based on a difference value between illumination parameters of the first photosensitive sensor and the second photosensitive sensor to obtain a light intensity of the external beam.