Buried Numerical Aperture Expander for Compact HUDs
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Solution Overview
Problem
The challenge in creating a head-up display (HUD) with a larger field of view is the need for larger displays or bulky optics, which are often not feasible due to space constraints in vehicles, and existing diffraction elements do not effectively address this issue.
Innovation Solution
A buried numerical aperture expander is used, comprising a light transmissive first layer with a micro lens array and a reflective layer, allowing for the expansion of incident light rays to provide a larger field of view while maintaining transparency for ambient light, enabling a virtual display on a glass surface like a windshield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If larger displays or bulky optics are used to achieve a larger field of view, then the field of view is improved, but the device size and space requirements increase
Solution Approach 1:
The patent applies dimensionality change by transitioning from a planar display approach to a three-dimensional optical expansion approach. The micro lens array creates a virtual three-dimensional image space that expands the field of view without increasing the physical footprint of the display device, allowing a larger effective display area in the angular dimension while maintaining a compact form factor.
Solution Approach 2:
The patent uses optical copying through the micro lens array to create multiple virtual images of the same display content at different angular positions. This allows a single physical display to present information across a wider field of view by copying and redistributing the light paths, eliminating the need for a larger physical display area.
2Volume of moving object
If traditional flat panel displays are used, then the display size is reduced, but the field of view remains limited
Solution Approach 1:
The patent resolves this contradiction by introducing angular dimensionality through the micro lens array. Instead of increasing the physical display area, the system expands the field of view by creating multiple angular pathways for light, effectively adding a dimensional degree of freedom that allows a compact display to present a wide field of view.
3Reliability
If a transparent display is used to maintain visibility, then transparency is improved, but the display brightness and contrast may be reduced
Solution Approach 1:
The patent applies segmentation by using an array of discrete micro lenses that individually control light paths. Each micro lens segment can be optimized to direct specific portions of the display image to different angular positions, allowing the system to maintain high brightness and contrast in the displayed regions while preserving transparency in other areas through selective optical routing.
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 solution allows for a larger field of view in HUDs without the need for bulky optics, while maintaining transparency for the driver to see through the windshield, enhancing situational awareness and safety features like adaptive cruise control and collision avoidance.
Implementation Method 1
A buried numerical aperture expander is used, comprising a light transmissive first layer with a micro lens array and a reflective layer, allowing for the expansion of incident light rays to provide a larger field of view
Implementation Method 2
A buried numerical aperture expander is used, comprising a light transmissive first layer with a micro lens array and a reflective layer
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
Briefly, in accordance with one or more embodiments, a buried numerical aperture expander (100) may be utilized to provide a head-up or virtual display at a larger field of view without requiring a larger amount of space, larger sized display, or larger sized optics. The buried numerical aperture expander is capable of selectively reflecting light emanating from a display such that the reflected light is expanded into a larger field of view, while simultaneously allowing other light to be transmitted through the buried numerical aperture expander without expansion so that the buried numerical aperture expander may be deployed in conjunction with a windshield or window without adversely affecting the ability to see through buried numerical aperture expander.