Single-Mirror HUD Optics for Compact Distortion-Corrected Projection
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Solution Overview
Problem
Conventional head-up display (HUD) apparatuses face limitations in size reduction due to the need for two mirrors, which restricts layout possibilities and increases the overall apparatus size, and fail to effectively correct distortion and aberration in the virtual image.
Innovation Solution
A HUD apparatus design using a single concave mirror and a distortion correcting lens to project images onto a windshield, eliminating the optical path return mirror and optimizing the housing structure to reduce size while correcting distortion and aberration, with a modular and heat-dissipating image display system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two mirrors are installed between observer and display apparatus, then the virtual image can be displayed, but the apparatus size is increased due to layout restrictions and clearance requirements
Solution Approach 1:
The patent removes the optical path return mirror from the conventional two-mirror configuration, retaining only the essential concave mirror to form the virtual image. This extraction of the non-essential component reduces the number of mirrors from two to one, thereby decreasing the apparatus size while maintaining the core functionality of virtual image display.
Solution Approach 2:
The patent employs an aspherical concave mirror with specifically designed curvature radii in different directions (Rx = 300mm in the horizontal direction, Ry = 450mm in the vertical direction). This dimensional differentiation allows the single mirror to compensate for distortion and aberration that would normally require multiple mirrors, achieving the same optical correction function in a more compact configuration.
2Volume of stationary object
If two mirrors are closely disposed to reduce size, then apparatus capacity is reduced, but reflected light flux is shielded by the second mirror
Solution Approach 1:
By removing the optical path return mirror entirely, the patent eliminates the problem of light flux shielding that occurs when two mirrors are closely disposed. The single concave mirror configuration ensures that all reflected light reaches the observer without being blocked by a second mirror, thus preventing energy loss while maintaining compact apparatus capacity.
3Adaptability or versatility
If conventional two-mirror configuration is used, then layout flexibility is limited, but distortion and aberration correction is insufficient
Solution Approach 1:
The patent uses an aspherical concave mirror with different curvature radii in horizontal (Rx = 300mm) and vertical (Ry = 450mm) directions. This dimensional asymmetry provides superior distortion and aberration correction compared to conventional spherical mirrors, while the single-mirror design offers greater layout flexibility than two-mirror configurations.
Solution Approach 2:
The patent optimizes specific parameters of the concave mirror including its focal length (f = 150mm), curvature radii (Rx = 300mm, Ry = 450mm), and the distance from the display apparatus to the mirror (100mm). These parameter changes enable effective distortion and aberration correction while maintaining layout flexibility and compact size.
4Volume of stationary object
If single concave mirror and distortion correcting lens are used, then apparatus size is reduced, but optical path management becomes more challenging
Solution Approach 1:
The patent removes the optical path return mirror to reduce apparatus size, compensating for the simplified optical path management through the use of an aspherical concave mirror that inherently corrects distortion and aberration, eliminating the need for complex multi-element optical systems.
Solution Approach 2:
The patent combines a concave mirror with aspherical surfaces with a distortion correcting lens in a composite optical system. This combination leverages the focusing capability of the mirror and the distortion correction capability of the lens to achieve superior image quality in a compact configuration, managing optical path complexity through synergistic component integration.
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 solution enables a more compact HUD apparatus with improved image quality by reducing distortion and aberration, enhancing user experience through a smaller, more efficient, and reliable display system.
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 generated by the concave mirror
Implementation Method 3
a light source provided with heat dissipating means
Implementation Method 4
heat dissipating means
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.