Virtual Image Display Optics for Double-Image Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing virtual image display technologies require a large viewing distance to minimize double images, and there is a need to reduce double images regardless of the viewing distance for improved visibility.
Innovation Solution
A virtual image display device with a projection optical system that includes a projection mirror with a concavely curved surface, where the image display light is incident and reflected diagonally, and the display unit is positioned at the focal point of a composite optical system within a meridional plane, reducing astigmatism and double images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a large viewing distance is used to reduce double images, then the occurrence of double images is reduced, but the adaptability to different viewing distances deteriorates
Solution Approach 1:
The invention applies curved surfaces (concave and convex) to the projection mirror and virtual image presentation plate. The projection mirror has a concavely curved surface that focuses light, while the virtual image presentation plate has a convexly curved surface that presents the virtual image. This curvature configuration reduces astigmatism and eliminates double images by properly focusing the light paths, allowing the system to work effectively at various viewing distances without requiring a large fixed viewing distance.
Solution Approach 2:
The invention changes the optical parameters of the system by using a composite optical system where the display unit is positioned at the focal point. The projection mirror and virtual image presentation plate are configured with specific curvature radii and positions that optimize the light paths. By adjusting these optical parameters (curvature, position, focal length), the system achieves reduced astigmatism and eliminated double images across different viewing distances, improving adaptability.
2Illumination intensity
If a composite optical system with curved surfaces is used to reduce astigmatism, then the visibility of virtual image is improved, but the device complexity increases
Solution Approach 1:
The invention merges the projection mirror and virtual image presentation plate into a composite optical system where both components work together synergistically. The projection mirror with its concavely curved surface and the virtual image presentation plate with its convexly curved surface are integrated to form a unified optical path that reduces astigmatism. This combined approach achieves improved virtual image visibility while managing complexity through functional integration rather than separate corrective components.
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 effectively reduces the occurrence of double images and enhances the visibility of the virtual image without the need for specialized windshield configurations like wedge glass, thereby improving user experience across various viewing distances.
Implementation Method 1
a projection mirror that projects the image display light toward the virtual image presentation plate such that the image display light is incident and reflected on a concavely curved surface
Implementation Method 2
The display unit is provided at a focal point of a composite optical system within a meridional plane, the composite optical system being formed by the virtual image presentation plate and the projection optical system
Data Source
Figure 1~2
Figure 3~4
Figure 5A~5B
AI summary
A virtual image display device 410 includes a projection optical system 414 that includes a projection mirror 416 that projects an image display light L toward a virtual image presentation plate 22 such that the image display light L is incident and reflected on a concavely curved surface of the virtual image presentation plate 22 diagonally. The projection mirror 416 has a convexly curved surface on which the image display light L is incident and reflected diagonally and is arranged such that a direction orthogonal to both a direction of incidence and a direction of reflection of the image display light L on the concavely curved surface and a direction orthogonal to both a direction of incidence and a direction of reflection of the image display light L on the convexly curved surface are parallel to each other. The display unit 12 is provided at a focal point of a composite optical system 414 within a meridional plane, the composite optical system being formed by the virtual image presentation plate L and the projection optical system 22. The focal point of the composite optical system 414 within the meridional plane is a position of convergence of parallel beams assumed to be incident from the user E toward the virtual image presentation plate 22 along the meridional plane of the virtual image presentation plate 22.