Electrochromic Dimming Device for AR Head-Mounted Display
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Solution Overview
Problem
Display apparatuses used in augmented reality head-mounted displays often fail to provide sufficient contrast in bright environments, making it difficult for users to safely navigate and recognize their external surroundings while wearing the device.
Innovation Solution
Incorporating a dimming device with a configuration of electrodes and a dimming layer using electrochromic materials, where the light blocking ratio is adjustable across different regions, allowing for higher contrast and improved visibility of the external environment by preventing the overlap of projection images from the electrodes, and utilizing an optical shutter for color change through oxidation-reduction reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a dimming device with electrochromic materials is added to improve contrast and visibility, then the light blocking ratio can be adjusted to enhance virtual image display, but the device complexity increases due to additional electrodes and dimming layer structure
Solution Approach 1:
The patent combines the dimming device with the image forming device by integrating the first and second electrodes directly into the image forming device structure. The dimming layer is positioned between these electrodes within the same device housing, merging two separate functions (image display and dimming control) into a single integrated unit, thereby reducing overall system complexity despite adding dimming functionality
Solution Approach 2:
The first and second electrodes serve dual purposes: they function as electrode structures for the electrochromic dimming mechanism while also serving as conductive elements for the image forming device. This multi-functionality allows the same components to control both light blocking and image display operations, reducing the need for separate dedicated components
2Illumination intensity
If the light blocking ratio is increased to improve virtual image contrast, then visibility of virtual images is enhanced, but the ability to recognize the external environment deteriorates
Solution Approach 1:
The patent implements dynamic control of the light blocking ratio through independently controllable first and second electrodes. The control device can adjust the dimming level in real-time based on environmental conditions and user needs, allowing the system to switch between high contrast mode for virtual images and high transparency mode for external environment visibility, rather than being fixed at a single dimming level
Solution Approach 2:
The dimming layer is positioned specifically between the first and second electrodes in a localized region of the optical path. This localized dimming approach allows selective control of light blocking in specific areas, enabling the system to enhance virtual image contrast where needed while maintaining external visibility in other regions, rather than uniformly blocking light across the entire field of view
3Ease of operation
If electrodes are positioned to create projection images for dimming control, then light blocking functionality is achieved, but the projection images from electrodes may overlap and cause interference
Solution Approach 1:
The patent positions the first electrode and second electrode asymmetrically within the image forming device, with the first electrode on one side and the second electrode on the opposite side. This asymmetric arrangement ensures that their respective projection images do not overlap, as each electrode projects its image in a different spatial region, thereby eliminating interference while maintaining effective light blocking control
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 enables high contrast virtual image display and safe navigation in real environments by adjusting the light blocking ratio, ensuring the observer can clearly see their feet and surroundings, thus enhancing safety and usability.
Implementation Method 1
a dimming layer interposed between the first transparent electrode and the second transparent electrode... the light blocking ratio of the dimming device is changed... utilizing an optical shutter for color change through oxidation-reduction reactions
Implementation Method 2
the light blocking ratio of the dimming device is changed... by preventing the overlap of projection images from the electrodes
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
A display apparatus includes a frame mounted on an observer' s head, an image display device attached to the frame and a dimming device 700, the image display device includes an image forming device and an optical device 120, 320 having a virtual image forming region 140, 340 where a virtual image is formed on the basis of light emitted from the image forming device, the optical device 120, 320 overlaps with a portion of the dimming device 700, at the time of operation of the dimming device 700, a light blocking ratio of the dimming device 700 is changed over a range of from an upper region 701U to a lower region 701D and/or over a range of from an inner region 701C to an outer region 701S, and a virtual image forming region facing region 701 has a light blocking ratio higher than the light blocking ratio of the lower region 701D or the outer region 701S.