Adjustable-Tint Lenses for Head-Mounted Displays
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Head-mounted devices struggle to effectively balance the visibility of both real-world and computer-generated images in bright environments, as ambient light often overwhelms the projector images, leading to reduced visibility of virtual content.
Innovation Solution
The integration of an electrically adjustable light modulator with electrode structures using portions of the waveguide and/or outer lens elements as substrates, allowing dynamic adjustment between higher transmission for real-world visibility and lower transmission for enhanced projector image visibility, utilizing electrochromic or liquid crystal materials to control light transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the light modulator is set to higher transmission state to enhance real-world visibility, then real-world object visibility is improved, but projector image visibility deteriorates due to ambient light overwhelming the virtual content
Solution Approach 1:
The light modulator is designed to be dynamically adjustable between different transmission states (higher and lower transmission modes). This allows the system to adapt its light transmission properties in real-time based on environmental conditions and usage requirements, resolving the contradiction by enabling the user to switch between optimizing for real-world visibility versus projector image visibility
Solution Approach 2:
The light modulator changes its transmission parameter electrically between distinct states. By controlling the transmission parameter of the light modulator, the system can adjust the amount of ambient light passing through the lens element, thereby resolving the contradiction between allowing sufficient ambient light for real-world visibility and blocking enough ambient light to make projector images visible
2Reliability
If the light modulator is set to lower transmission state to enhance projector image visibility, then projector image visibility is improved, but real-world object visibility deteriorates due to reduced ambient light transmission
Solution Approach 1:
The light modulator's dynamic adjustability allows the system to switch to a lower transmission state when projector image visibility is the priority. This dynamic state change enables the system to overcome the contradiction by temporarily reducing ambient light transmission to make faint projector images visible, while preserving the ability to switch back when real-world visibility is needed
Solution Approach 2:
By electrically controlling the transmission parameter of the light modulator to a lower state, the system reduces the amount of ambient light that passes through the lens element. This parameter change directly addresses the contradiction by filtering out sufficient ambient light to enable projector image visibility while maintaining the optical path integrity for when real-world visibility is required
3Reliability
If a fixed tint layer is used to reduce ambient light, then projector image visibility is improved in bright environments, but adaptability to different lighting conditions deteriorates
Solution Approach 1:
The invention replaces a fixed tint layer with a dynamically controllable light modulator that can electrically switch between different transmission states. This dynamic capability resolves the contradiction by enabling the system to adapt to different lighting conditions (bright environments, dim environments, indoor/outdoor transitions) while maintaining the ability to reduce ambient light when projector image visibility is required
Solution Approach 2:
The light modulator serves multiple functions: it can enhance projector image visibility in bright environments by reducing ambient light transmission, and it can maintain full real-world visibility in dim or indoor environments by switching to higher transmission state. This multi-functionality resolves the contradiction between optimizing for bright environment performance and maintaining adaptability across diverse lighting conditions
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 enhances the visibility of computer-generated images by reducing ambient light interference, ensuring that virtual content remains visible and comfortable to view in bright conditions without compromising real-world object clarity.
Implementation Method 1
an adjustable tint layer that can be used to dynamically attenuate real-world image light
Implementation Method 2
electrically adjustable light modulator... utilizing electrochromic or liquid crystal materials to control light transmission
Data Source
AI summary
A head-mounted device may have eyeglass lenses. Each eyeglass lens may have an optical system with inner and outer lens elements and a waveguide and light modulator between the inner and outer lens elements. The waveguide of each system may be configured to receive and guide an image from a projector. The waveguide may have a may have an output coupler configured to direct the image out of the waveguide through the inner lens element to an eye box for viewing by a user. The light modulator in each optical system may be electrically adjustable between a higher transmission state that enhances the visibility of real-world objects through the lens and a lower transmission state that dims ambient light to enhance the visibility of the image from the projector. The light modulator layer may have electrode structures that use portions of the waveguide and/or outer lens element as substrates.