Virtual Image Display Device Optical Path Compensation
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Solution Overview
Problem
Conventional virtual image display devices experience significant differences in resolution across regions due to the warping process used to reduce distortion, leading to varying numbers of pixels and resolutions in expanded and narrowed regions.
Innovation Solution
The virtual image display device employs a translucent screen inclined with respect to the optical axis, combined with a light distribution adjustment part and a reflective system, to adjust the light distribution and optical path lengths, ensuring consistent resolution across regions by minimizing the difference in optical path lengths and projectable areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a warping process is applied to reduce distortion of the virtual image, then the distortion is reduced, but the resolution difference between expanded and narrowed regions increases
Solution Approach 1:
The invention applies local quality by differentiating the optical path configuration for different regions of the image. The light distribution adjustment part creates different optical path lengths for light beams corresponding to expanded regions versus narrowed regions, allowing each region to be optimized independently. This resolves the contradiction by enabling distortion correction through warping while maintaining uniform resolution across all regions through localized optical path compensation.
Solution Approach 2:
The invention changes optical parameters (optical path length, light distribution) to resolve the contradiction. By adjusting the optical path length difference between different regions through the light distribution adjustment part, the system compensates for resolution variations caused by warping. This parameter change approach allows simultaneous achievement of distortion reduction and resolution uniformity.
2Device complexity
If the optical path length difference between regions is large, then the device structure is simpler, but the resolution difference between regions increases
Solution Approach 1:
The light distribution adjustment part serves as an intermediary element between the projection system and the display surface. This intermediary component compensates for optical path length differences by adjusting light distribution, thereby maintaining resolution uniformity without requiring complete redesign of the entire optical system. This resolves the contradiction by providing a relatively simple additional component that achieves the desired precision.
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 reduces the difference in resolution between regions of the virtual image, minimizing distortion and maintaining consistent image quality across the display area.
Implementation Method 1
a translucent screen 20... a first reflection part 30 that reflects display light 200... a second reflection part 40 that reflects the display light 200
Implementation Method 2
a translucent screen 20... disposed inclined with respect to the optical axis 100A... adjusts the light distribution
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The present invention makes it possible to reduce a difference in resolution between respective regions of a virtual image while reducing distortion of an image. A translucent screen 20 is disposed to be inclined with respect to an optical axis 100A of projection light 100 such that a difference between a first optical path length 201L to a first reflection part 30 of the display light 201 emitted from a first end 21 far from display light 200 reflected toward a second reflection part 40 by the first reflection part 30, and a second optical path length 202L of display light 202 emitted from a second end 22 closer to 200 reflected toward the second reflection part 40 by the first reflection part 30 than the first end 21 becomes smaller.