Compact HUD Optical Layout Using a Single Concave Mirror
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Solution Overview
Problem
Conventional head-up display (HUD) apparatuses face limitations in size reduction due to the need for multiple mirrors, which restricts layout possibilities and increases housing size.
Innovation Solution
A HUD apparatus design that uses a single concave mirror and a distortion correcting lens to project images onto a windshield, eliminating the need for additional mirrors and optimizing the housing structure for reduced size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If two mirrors are installed between the observer and display apparatus to reduce screen distortion, then the image quality is improved, but the apparatus size and housing capacity increase
Solution Approach 1:
The patent removes one mirror from the optical system, extracting the unnecessary component while maintaining the essential function of image projection. This reduces the number of mirrors from two to one, directly decreasing the apparatus size and housing capacity while still achieving acceptable screen distortion through optimized single-mirror design and optical parameters.
Solution Approach 2:
The patent changes the optical path configuration by eliminating the need for multiple mirror reflections and instead uses a direct projection path with a single mirror. This dimensional simplification of the optical system reduces the spatial requirements and allows for a more compact apparatus design while maintaining image quality.
2Volume of stationary object
If two mirrors are closely disposed to reduce apparatus size, then the housing capacity is reduced, but the layout flexibility is limited and clearance requirements increase
Solution Approach 1:
By removing one mirror from the system, the patent eliminates the clearance requirements and layout constraints associated with positioning multiple mirrors in close proximity. This extraction of the unnecessary mirror component provides greater design freedom and adaptability in arranging the remaining optical elements within the housing.
3Use of energy by moving object
If the clearance between two mirrors is increased to prevent light flux shielding, then the reflected light flux is optimized, but the apparatus size increases
Solution Approach 1:
The patent removes one mirror that was causing light flux shielding issues, thereby eliminating the need for increased clearance between mirrors. This extraction resolves the conflict between optimizing reflected light flux and minimizing apparatus size, as the single-mirror configuration naturally avoids the shielding problem while maintaining a compact form factor.
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 design achieves a further reduction in size and capacity of the HUD apparatus while maintaining image quality and correcting distortion and aberration, enhancing visual confirmation for drivers.
Implementation Method 1
a virtual image optical system configured to reflect the light emitted from the image display apparatus onto a windshield
Implementation Method 2
a distortion correcting lens configured to correct distortion and aberration of the virtual image
Data Source
AI summary
An object of the present invention is to provide a head-up display apparatus further reduced in size, the head-up display apparatus having: an image display apparatus including a light source and a display element; and a virtual image optical system in which light emitted from the image display apparatus is reflected by a windshield or a combiner of the vehicle so that a virtual image is displayed in front of the vehicle, wherein the virtual image optical system has a concave mirror and a distortion correcting lens, and the distortion correcting lens is disposed between the image display apparatus and the concave mirror, the concave mirror is disposed in a housing including an outer case along a shape of an effective light path area of the image light from the image display apparatus, and the image display apparatus is attached to part of an outer periphery of the housing.