Head-Up Display Double Reflection Mirror Optical Path Folding
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Solution Overview
Problem
Head-up display devices require a small size and minimal aberration while maintaining a wide vertical eye box range to accommodate varying driver positions and heights, which is challenging due to the need for a long optical path and limited device space.
Innovation Solution
A head-up display device design incorporating a first optical system with a double reflection mirror and a second optical system, including at least one concave mirror, to form an intermediate image and ensure a wide eye box range, while minimizing device size and aberration through the use of a stop and specific mirror configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the optical path length is increased to ensure a wide vertical eye box range, then the eye box range is improved, but the device size increases
Solution Approach 1:
The patent introduces a double reflection mirror that reflects light twice, effectively folding the optical path into a compact configuration. This allows the optical path length to be extended in a dimensional sense without increasing the physical footprint of the device, thereby achieving a wide vertical eye box range while maintaining a small device size.
Solution Approach 2:
The optical system is arranged with multiple mirrors (first concave mirror, second concave mirror, and double reflection mirror) nested within a compact space. The double reflection mirror is positioned to utilize the space between other optical components, allowing the optical path to be folded back on itself and maximizing the use of available space to achieve both long optical path and compact size.
2Manufacturing precision
If the curvature of the concave mirror is reduced to suppress aberration, then the aberration is improved, but the optical path length increases
Solution Approach 1:
The optical system is divided into multiple segments with different functions: the first concave mirror for initial reflection, the second concave mirror for additional optical path folding, and the double reflection mirror for final image formation. This segmentation allows each mirror to have optimized curvature for its specific function, suppressing aberration while maintaining a compact overall optical path length.
Solution Approach 2:
The double reflection mirror acts as an intermediary element between the first and second concave mirrors. It reflects light twice, effectively extending the optical path without requiring a single mirror with excessive curvature reduction, thereby suppressing aberration while controlling the overall optical path length.
3Volume of moving object
If multiple mirrors are combined to bend the optical path, then the device size is reduced, but the device complexity increases
Solution Approach 1:
The double reflection mirror serves multiple functions simultaneously: it reflects light twice to extend the optical path, it acts as a beam steering element, and it helps define the final image position. This multi-functionality reduces the need for additional separate components, thereby reducing device complexity while achieving compact size.
Solution Approach 2:
The patent combines the functions of multiple mirrors into a unified optical system where the first concave mirror, second concave mirror, and double reflection mirror work together in sequence. The optical paths are merged and folded efficiently, creating a compact device without requiring complex separate subsystems for each function.
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 compact head-up display device with reduced aberration and a wide vertical eye box range, allowing for flexible optical system arrangement and improved display contrast.
Implementation Method 1
a first optical system including at least one concave mirror, and a second optical system including at least one concave mirror, arranged along an optical path of display light in order from an image display surface side. An intermediate image is formed between the first and second optical systems on the optical path, and the first optical system includes a double reflection mirror that reflects the display light twice on the optical path.
Implementation Method 2
reflects display light of an image, which is displayed on an image display surface, toward an observer by an image-reflecting surface facing the observer to enlarge and display the image to the observer as a virtual image beyond the image-reflecting surface
Data Source
AI summary
There is provided a head-up display device which has a small size and of which the aberration is small and the range of an eye box in a vertical direction is wide. The head-up display device 10 includes a first optical system that includes at least one concave mirror arranged along an optical path of display light in order from an image display surface 1, and a second optical system that includes at least one concave mirror arranged along the optical path of the display light in order from the image display surface 1 side. An intermediate image is formed between the first and second optical systems on the optical path, and the first optical system includes a double reflection mirror that reflects the display light twice on the optical path.