Virtual Image Optical System with Adjustable Reflective Surfaces
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing virtual image display devices face issues with viewability due to changes in the incident angle of light rays when the movable mirror is moved, leading to differences in brightness and reduced visibility for the occupant.
Innovation Solution
A virtual image optical system with a first and second reflective surface, where the optical path length from the display surface to the second reflective surface is adjustable, allowing the position of the pupil to be changed through rotation of the second reflective surface, and the angle between the moving direction of the first reflective surface and the principal ray is maintained at 5° or less to minimize changes in incident angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the movable mirror is moved to change the relative position between the occupant and the virtual image, then the position adaptability is improved, but the incident angle of light rays changes greatly causing brightness difference and viewability reduction
Solution Approach 1:
The patent applies dynamics by making the first reflective surface movable along the optical path direction to change the optical path length, and the second reflective surface rotatable to change the pupil position. This dynamic adjustment allows the system to adapt to different viewing positions while maintaining optimal light incident angles through coordinated movement, thereby preserving brightness consistency across different virtual image positions.
2Adaptability or versatility
If the movable mirror is moved to adjust the virtual image position, then the viewability adaptability is improved, but the device complexity increases due to additional adjustment mechanisms
Solution Approach 1:
The patent segments the adjustment function into two independent parts: the first reflective surface handles optical path length adjustment along the optical path direction, while the second reflective surface handles pupil position adjustment through rotation. This segmentation allows each component to perform a specific function with simple movement, avoiding the need for complex multi-degree-of-freedom mechanisms and reducing overall device complexity.
3Adaptability or versatility
If the angle between the moving direction of the first reflective surface and the principal ray is increased to allow larger movement range, then the adjustment range is improved, but the incident angle change becomes significant causing brightness variation
Solution Approach 1:
The patent resolves the contradiction by introducing a second dimension of adjustment through the rotatable second reflective surface. The first reflective surface moves strictly along the optical path direction (one dimension) to maintain incident angle and brightness, while the second reflective surface rotates to adjust the pupil position in a different dimension. This dimensional separation allows large adjustment range without compromising brightness stability.
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
This configuration ensures consistent viewability by reducing the difference in brightness and maintaining optimal positioning of the virtual image, even when the user's visual point changes, thereby enhancing the overall visibility of the virtual image.
Implementation Method 1
a first reflective surface 102 arranged to reflect the light from the display surface 101
Implementation Method 2
a second reflective surface 103 arranged to reflect light from the first reflective surface 102
Data Source
AI summary
A virtual image optical system with which a virtual image is formed by introducing light from a display surface to a pupil includes a first reflective surface arranged to reflect the light from the display surface, and a second reflective surface arranged to reflect light from the first reflective surface. An optical path length from the display surface to the second reflective surface is changeable with movement of the first reflective surface, a position of the pupil is changeable with rotation of the second reflective surface in a direction having a component in a direction perpendicular to an optical path of a principal ray incident on the pupil, and an angle formed between a moving direction of the first reflective surface and the principal ray incident on the first reflective surface is 5° or less.