Holographic Optical Element Aberration Compensation for HUD
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Solution Overview
Problem
Existing head-up display (HUD) systems face challenges in maintaining image quality at long distances due to aberrations caused by the projection optical system, which degrades the image displayed on the HUD image plane.
Innovation Solution
A method for fabricating a holographic optical element (HOE) that measures and compensates for aberrations in the projection optical system by recording the aberrated wavefront on a master HOE, allowing it to interfere with a spherical wave and correct the image focus on the HUD image plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the projection optical system is used to focus the image on the HUD image plane, then the image can be displayed at a long distance, but the aberration caused by the optical system degrades the image quality
Solution Approach 1:
The patent applies preliminary anti-action by pre-compensating for the optical aberrations in the projection system. A compensation HOE is designed and fabricated with wavefront characteristics that are opposite to the aberrations introduced by the projection optical system. This pre-compensation ensures that when the light passes through the projection system and interacts with the compensation HOE, the aberrations are corrected, maintaining high image quality at long display distances
Solution Approach 2:
The compensation HOE serves as an intermediary element between the projection optical system and the HUD image plane. It mediates the optical path by introducing a counteracting wavefront that compensates for the aberrations generated by the projection system, thereby preserving image quality without requiring modification to the projection system itself
2Ease of operation
If the HOE is designed to focus the image at a long distance, then the user convenience is enhanced, but the aberration from the projection system causes image quality degradation
Solution Approach 1:
The compensation HOE is designed with wavefront characteristics that pre-compensate for the projection system's aberrations. By embedding the compensation function into the HOE fabrication process itself, the system maintains high image quality while enabling long-distance display for enhanced user convenience
Solution Approach 2:
The patent changes the wavefront parameters of the light by using the compensation HOE to modify the phase and amplitude distribution. This parameter transformation compensates for the aberrations introduced by the projection system, allowing the system to achieve both long display distance and high image quality
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 method enhances the quality of the HUD image by effectively compensating for aberrations, enabling clear image projection at long distances.
Implementation Method 1
causing the reproduced aberrated wavefront and a spherical wave emitted from an HUD image plane on which the image of the display device is focused to interfere with each other, and recording the wavefront on the HOE
Data Source
AI summary
Provided is a method in which, when configuring an HUD that produces a holographic image at a distance using a holographic optical element (HOE), an HOE capable of correcting aberrations generated by a projection optical system is manufactured and used to improve the quality of an HUD image. A method for manufacturing an HOE for HUD according to an embodiment of the present invention comprises the steps of: measuring aberrations generated by an optical system that projects an image of a display device; recording the measured aberrations in a master HOE; reproducing an aberrated wavefront of the optical system by playing the master HOE on a display plane on which the image of the display device is expressed; and causing an interference of the reproduced aberrated wavefront and a spherical wavefront irradiated from the HUD image plane on which the image of the display device is created, and recording the interference in the HOE. Accordingly, when configuring the HUD producing an image at a distance using the HOE, the quality of the HUD image can be improved by measuring aberrations in the projection optical system, creating a master HOE that reproduces the measured aberrations, and manufacturing a HOE that corrects the aberrations, and correcting aberrations generated in the projection optical system.