Optical Flow Sensor Pixel Switching for Variable Cover Stacks
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Solution Overview
Problem
Optical flow sensors face performance deterioration due to user modifications of the cover stack, such as the addition of screen protectors or cases, which cause flare, contrast loss, and changes in magnification ratio, affecting target tracking accuracy.
Innovation Solution
Adaptive optical flow sensors that include a transceiver optical design to mitigate flare, maintain optimal depth of field and magnification ratio, and adjust pixel read-out modes based on cover stack thickness, using a processor to analyze flare patterns and determine cover stack thickness for accurate tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the optical flow sensor transmits and receives light through the cover stack, then the sensor can detect target movement, but user modifications to the cover stack (such as adding screen protectors or cases) cause flare, contrast loss, and magnification ratio changes that interfere with tracking accuracy
Solution Approach 1:
The patent implements dynamic adaptation of the optical flow sensor by switching between binned and non-binned pixel modes based on detected cover stack thickness. The system dynamically adjusts its operational parameters to compensate for variations in cover stack thickness, maintaining tracking accuracy across different configurations.
Solution Approach 2:
The patent changes the operational parameters of the image sensor (binning mode) based on the detected cover stack thickness. By adjusting the pixel read-out mode parameter, the system compensates for optical distortions caused by different cover stack configurations, thereby maintaining reliable target tracking.
2Reliability
If the optical flow sensor uses a fixed pixel read-out mode, then the device complexity is reduced, but the sensor cannot accurately track targets through varying cover stack thicknesses
Solution Approach 1:
The optical flow sensor system performs self-diagnosis by analyzing flare patterns in captured images to automatically determine the cover stack thickness. The system then self-adjusts by switching between binned and non-binned pixel modes without requiring external intervention, thereby maintaining tracking accuracy while keeping the adaptation mechanism relatively simple.
Solution Approach 2:
The system uses feedback from image analysis (flare pattern detection) to dynamically adjust the pixel read-out mode. The processor analyzes the captured images, determines the cover stack thickness based on flare characteristics, and adjusts the binning configuration accordingly, creating a closed-loop control system that maintains optimal performance.
3Illumination intensity
If the optical flow sensor operates in non-binned pixel mode, then the image resolution is maintained, but the sensor is sensitive to flare from thin cover stacks; if operated in binned pixel mode, then flare sensitivity is reduced, but image resolution decreases
Solution Approach 1:
The patent dynamically switches between binned and non-binned pixel modes based on the detected cover stack thickness. For thin cover stacks where flare is problematic, the system uses binned mode to reduce flare sensitivity. For thicker cover stacks where flare is less of an issue, the system switches to non-binned mode to maintain full image resolution.
Solution Approach 2:
The system changes the pixel read-out parameter (binning configuration) based on the optical conditions created by different cover stack thicknesses. This parameter adaptation allows the sensor to optimize the trade-off between image resolution and flare sensitivity for each specific operating condition.
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
Ensures consistent optical flow tracking performance and user experience by adapting to various cover stack thicknesses, minimizing flare and maintaining target tracking accuracy.
Implementation Method 1
transmitted light may pass through the cover and be redirected from (e.g., reflected or scattered from) a target. The redirected light may then pass back through the cover and be sensed by the optical flow sensor
Implementation Method 2
a depth of field (DoF) extension lens disposed between the image sensor and the cover stack, in a light reception path of the image sensor
Data Source
AI summary
An opto-electronic device includes an optical sensor. The optical sensor includes an image sensor having a two-dimensional (2D) array of pixels, and a light source operable to illuminate at least a portion of a field of view imaged by the image sensor. The opto-electronic device also includes a cover stack that passes light emitted by the light source and light received by the image sensor, and a processor. The processor is configured to determine a thickness of the cover stack, and operate at least a portion of the 2D array of pixels in one of a binned pixel mode or a non-binned pixel mode, responsive to the determined thickness of the cover stack.