Optical Navigation Lens Orientation for MTF Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optical navigation systems face issues with uneven modulation transfer function (MTF) and high distortion due to the non-perpendicular orientation of the image sensor relative to the imaging lens, which degrades tracking performance.
Innovation Solution
The imaging lens is oriented substantially horizontally with respect to the target surface, ensuring its optical axis is perpendicular, thereby enhancing MTF and reducing distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the image sensor is tilted to the angle of specular reflection to capture maximum reflected light, then the light capture efficiency is improved, but the modulation transfer function (MTF) becomes uneven and distortion increases
Solution Approach 1:
Instead of tilting the image sensor to match the specular reflection angle, the patent inverts the approach by keeping the image sensor perpendicular to the imaging lens optical axis and instead tilting the imaging lens itself. This inversion resolves the contradiction by maintaining even MTF and low distortion while still capturing sufficient reflected light through the tilted lens orientation.
Solution Approach 2:
The patent introduces the imaging lens as an intermediary element between the light source and the image sensor. By tilting the imaging lens rather than the image sensor, the system uses the lens as a mediator to capture reflected light at the specular angle while keeping the sensor plane perpendicular to the lens axis, thus maintaining optimal image quality parameters.
2Reliability
If the image sensor is tilted to align with the specular reflection angle, then the tracking performance in terms of light capture is improved, but the image quality metrics (MTF and distortion) deteriorate
Solution Approach 1:
The patent applies the inversion principle by reversing which component is tilted - instead of tilting the image sensor, the imaging lens is tilted. This allows the system to maintain both reliable tracking performance through proper alignment with the reflection angle and high image quality through perpendicular sensor-lens alignment.
Solution Approach 2:
The patent changes the orientation parameter of the imaging lens relative to the optical axis, tilting it by a specific angle (e.g., 45 degrees) to match the specular reflection angle. This parameter change enables the system to capture maximum reflected light while the image sensor remains perpendicular to the lens axis, preserving image quality metrics.
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 improves the overall tracking performance by maintaining high MTF across the field of view and minimizing distortion, resulting in more accurate and consistent image capture and navigation.
Implementation Method 1
The light source is positioned to emit illumination light onto a target surface at a nonzero angle of incidence with respect to the normal to the target surface. The image sensor array is positioned to receive the illumination light reflected from the target surface at a nonzero angle of reflection
Implementation Method 2
The imaging lens is positioned between the target surface and the image sensor array to receive and optically manipulate the illumination light reflected from the target surface
Data Source
AI summary
A system and method for performing optical navigation uses an imaging lens, which is positioned between a target surface and an image sensor array, that is orientated to be substantially horizontal with respect to the target surface such that the optical axis of the imaging lens is substantially perpendicular to the target surface.