Multifocal Display Refractive Focus Actuator for 3D Rendering
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Solution Overview
Problem
Conventional multifocal displays face challenges with mismatched convergence and accommodation cues, leading to visual fatigue and increased system complexity due to the need for high-speed focus actuators and magnification changes.
Innovation Solution
A multifocal display system incorporating a refractive focus actuator, such as a deformable liquid lens, positioned at the pupil plane of an optical imaging system, which allows for rapid focal modulation without significant changes in image size, synchronized with a controller to adjust focus and render 2D images, ensuring constant magnification and reduced system complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional multifocal displays use rapid temporal and focal modulation to render 3D scenes, then 3D perception quality is improved, but visual fatigue increases due to mismatched convergence and accommodation cues
Solution Approach 1:
The patent employs a deformable liquid lens that can dynamically change its focal length in real-time to match the displayed content depth. This dynamic focal adjustment allows the system to provide accurate accommodation cues that correspond to the perceived depth of 3D objects, resolving the convergence-accommodation conflict and reducing visual fatigue while maintaining high 3D perception quality
Solution Approach 2:
The system changes the optical parameter (focal length) of the liquid lens to match the depth of the displayed content. By adjusting the focal length parameter dynamically according to the rendered 3D scene depth, the system provides accurate focus cues that correspond to the perceived depth, thereby improving 3D perception while eliminating the visual fatigue caused by mismatched cues
2Measurement precision
If multifocal displays use a series of 2D images focused at parallel planes at different distances, then 3D scene depth is improved, but system complexity increases due to requirement for high-speed focus actuator
Solution Approach 1:
The patent uses a liquid lens actuated by hydraulic or pneumatic pressure to change its focal length. By applying pressure through a simple pressure source (such as a syringe or pressure regulator), the system achieves focal modulation without requiring complex mechanical actuators, thereby reducing system complexity while maintaining the ability to render multiple focal planes for accurate 3D depth perception
Solution Approach 2:
The system replaces complex mechanical focus actuators with a liquid lens that can be actuated by simple pressure changes. This substitution eliminates the need for high-speed mechanical moving parts, reducing system complexity and reliability issues while maintaining the capability to rapidly modulate focus across multiple planes for accurate 3D depth rendering
3Measurement precision
If the focal plane location is shifted in multifocal displays, then different depth planes are rendered, but magnification changes occur which increase system complexity
Solution Approach 1:
The patent introduces a field lens as an intermediary optical element between the liquid lens and the display. This field lens compensates for the magnification changes that occur when the liquid lens focal length is adjusted. By acting as an optical mediator, the field lens maintains constant image magnification across all focal planes, enabling accurate depth plane rendering without requiring complex computational correction or additional active magnification control mechanisms
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 provides improved visual performance by maintaining constant magnification, reducing visual fatigue, and enhancing the rendering of 3D scenes with increased field-of-view and dynamic range, while minimizing focal jitter and maintaining accurate depth perception.
Implementation Method 1
the refractive focus actuator is a deformable liquid lens and the waveform driving the liquid lens is designed to reduce ringing in the liquid lens
Data Source
AI summary
A multifocal display for rendering a 3D scene as a series of 2D images. In one aspect, the multifocal display includes a display, an optical imaging system, a refractive focus actuator and a controller. The display renders the 2D images. The optical imaging system is image-side telecentric and creates an image of the display. The refractive focus actuator is positioned at the pupil of the optical imaging system. Thus, adjusting the refractive focus actuator alters a location of the image of the display but does not significantly alter a size of the image. The controller coordinates adjustment of the refractive focus actuator with rendering of the 2D images on the display. The waveform driving the focus actuator is preferably designed to reduce ringing and jitter effects.