Tunable Liquid Lenses for Variable-Focus Head-Mounted Displays
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing head-mounted devices lack adjustable lenses that can accommodate users with varying vision needs and image display distances, limiting their versatility and user experience.
Innovation Solution
Incorporation of tunable liquid lenses with adjustable refractive index, actuated by control signals, to dynamically adjust focal length and optical properties, using actuators and refractive-index-adjustment particles to cater to individual vision requirements and image display positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fixed focal length lenses are used in head-mounted devices, then the device structure is simple, but the device cannot accommodate users with varying vision needs and different image display distances
Solution Approach 1:
The patent implements a tunable liquid lens where the focal length can be dynamically adjusted through electrical signals. The lens uses a liquid crystal material whose refractive index can be changed by applying different voltages, allowing the focal length to be tuned to accommodate different vision needs and image distances, transforming a static optical system into a dynamic one that adapts to user requirements
Solution Approach 2:
The patent changes the refractive index parameter of the lens material by using liquid crystal technology. By applying different voltages, the refractive index of the liquid crystal can be adjusted, which directly changes the focal length of the lens. This parameter change approach allows a single lens to provide multiple focal lengths, accommodating various vision corrections and display distances without requiring multiple physical lenses
2Adaptability or versatility
If multiple fixed lenses are provided for different vision needs, then user requirements are met, but the device complexity and number of components increase
Solution Approach 1:
The patent makes a single lens element perform multiple functions by enabling it to adjust its focal length continuously. The tunable liquid lens can serve as different types of corrective lenses (for nearsightedness, farsightedness, presbyopia) and can also adjust for different virtual reality image distances, replacing what would traditionally require multiple separate lens elements. This multi-functionality reduces the number of components while maintaining comprehensive adaptability
3Adaptability or versatility
If adjustable lenses are incorporated, then versatility for different vision needs is achieved, but the device weight and power consumption increase
Solution Approach 1:
The patent uses a liquid crystal-based tunable lens that adjusts focal length by changing the refractive index through electrical fields rather than mechanical movement. This eliminates the need for heavy mechanical adjustment mechanisms, moving parts, or multiple physical lens elements. The liquid crystal material itself is lightweight, and the electrical actuation requires minimal power, thus achieving lens tunability without significantly increasing device weight
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
Enhances user experience by providing adjustable lenses that accommodate different vision defects and image distances, ensuring clear and comfortable viewing of virtual or augmented reality content.
Implementation Method 1
Inorganic dielectric particles or other refractive-index-adjustment particles may be used to adjust the refractive index of the liquid in the lens chamber and thereby adjust the refractive index of the lens
Data Source
AI summary
A head-mounted device may have lenses. A user may view images through the lenses from eye boxes. The lenses may be tunable liquid lenses. Each lens may have a lens chamber. The lens chamber of the lens may have rigid and/or flexible walls that form optical lens surfaces. Actuators and/or pump and reservoir systems may deform the lens surfaces in response to control signals from a control circuit to tune the lens. Each liquid lens may have oil or other liquid in the lens chamber for that lens. Inorganic dielectric particles or other refractive-index-adjustment particles may be used to adjust the refractive index of the lens. The particles may be subwavelength in size.