Tunable Lens Test Fixture for HUD Windshield Evaluation
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Solution Overview
Problem
Current test fixtures for evaluating heads-up display (HUD) windshields face challenges due to complex windshield shapes, optical aberrations, and the need for precise spatial measurements, leading to unclear images and difficulties in assessing compliance with performance specifications.
Innovation Solution
A fully automatic test fixture with a tunable lens and computer configuration that compensates for optical and computational limitations, using a tunable lens to modify light and account for windshield curvature and aberrations, and a test matrix to evaluate HUD image quality with higher resolution and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed lens camera is used to capture HUD images, then the device complexity is reduced, but the measurement precision deteriorates due to inability to focus at multiple distances
Solution Approach 1:
The patent employs a tunable lens that can dynamically change its focal length to match different virtual image distances. This dynamic adjustment capability allows the camera to focus sharply on HUD images at various distances without requiring multiple fixed lenses, thereby improving measurement precision while maintaining relatively simple device architecture.
Solution Approach 2:
The tunable lens changes its optical parameter (focal length) based on the virtual image distance. By adjusting the focal length parameter to match the specific distance of the HUD virtual image, the system achieves precise focus for measurements, resolving the contradiction between measurement precision and device complexity.
2Measurement precision
If conventional test fixtures are used for complex windshield shapes, then the device complexity is minimized, but the measurement precision deteriorates due to optical aberrations and focus issues
Solution Approach 1:
The test fixture incorporates a tunable lens that can dynamically adjust its focal length to compensate for variations in windshield curvature and virtual image distances. This dynamic adjustment allows the system to maintain high measurement precision across different windshield shapes and orientations without requiring complex mechanical reconfiguration.
Solution Approach 2:
The system uses a computer to control the tunable lens based on the specific windshield being tested. The computer processes information about the windshield geometry and adjusts the lens focal length accordingly, providing feedback-based optimization that improves spatial measurement accuracy while keeping the overall fixture design manageable.
3Productivity
If manual testing methods are used for HUD windshields, then the device complexity is reduced, but the productivity deteriorates due to time-consuming evaluation processes
Solution Approach 1:
The test fixture is designed to be fully automatic, with the tunable lens and camera system automatically adjusting and capturing images without manual intervention. The computer controls the entire testing process, from lens adjustment to image capture and analysis, enabling rapid sequential testing of multiple windshields and significantly improving productivity.
Solution Approach 2:
The system replaces manual mechanical adjustment with automated electronic control of the tunable lens and camera. This substitution of mechanical operations with automated electronic systems increases testing speed and productivity while managing device complexity through integrated computer control.
4Measurement precision
If a fixed focal length lens is used, then the device complexity is minimized, but the measurement precision deteriorates due to inability to accommodate different virtual image distances
Solution Approach 1:
The patent uses a tunable lens whose focal length parameter can be changed electronically to match different virtual image distances. This parameter adjustment capability allows the system to maintain sharp focus and high measurement precision for HUD images at various distances without requiring a complex array of fixed focal length lenses.
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 test fixture provides accurate and reliable evaluation of HUD windshield performance, overcoming issues of focus and clarity, and enabling faster and more precise testing across various windshield models and orientations.
Implementation Method 1
The tunable lens modifies light that is reflected from the HUD surface and is incident on the lens by modifying an electronic version of the visual image or by modifying the size and/or shape of the lens to vary the visual image.
Implementation Method 2
The tunable lens is situated in the path of the illumination beam that travels from the test matrix to the HUD surface, and from the HUD surface to the camera. When the tunable lens is illuminated by the light beam from the test matrix, it modifies the light beam to compensate for the effects of the windshield's curvature and for optical aberrations in the HUD surface.
Implementation Method 3
The test matrix defines a test pattern that illuminates the HUD surface of the windshield and is reflected from the HUD surface to at least one tunable lens of a camera.
Data Source
AI summary
A test fixture (10) for HUD windshields (12) wherein aspherical devices (26) compensate for complex curvatures and optical aberrations in a heads-up display surface (16) of the windshield. Tunable lenses cooperate with a movable test matrix to improve image resolution and enhance ghost image reduction.