Disparity Waveguide Focus Adjustment for AR Display Brightness
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Solution Overview
Problem
Optical lenses in display systems are prone to performance variance due to temperature changes, manufacturing tolerances, and alignment issues, affecting focus and brightness, especially in faster lenses with smaller depth of field.
Innovation Solution
Implementing an adjustable focusing lens system with dual-photodiode disparity image sensors and processing logic to dynamically adjust the focus based on content-based and thermal defocus factors, using MEMS actuators and position sensors to align the lenses accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If faster lenses with smaller F-stop are used to increase brightness, then illumination intensity is improved, but depth of field decreases making the system more sensitive to focal length changes
Solution Approach 1:
The patent implements a dynamic focus adjustment system where the focusing lens can be moved along the optical axis in real-time. A disparity image sensor captures images at different focal planes, and processing logic calculates defocus factors to dynamically adjust the lens position, transforming the static optical system into a dynamic one that adapts to temperature changes and manufacturing variations.
Solution Approach 2:
The system employs a feedback mechanism where the disparity image sensor continuously monitors image quality and the processing logic uses calculated defocus factors to adjust the focusing lens position. This closed-loop feedback system compensates for focal length changes caused by temperature variations and manufacturing tolerances, maintaining optimal focus despite the reduced depth of field from using faster lenses.
2Measurement precision
If manual focus adjustment is used to compensate for temperature changes and manufacturing tolerances, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system implements self-service through automated focus adjustment. The disparity image sensor automatically captures images at different focal planes, the processing logic calculates the appropriate defocus factors, and the focusing lens is adjusted without user intervention. This eliminates the need for manual focus adjustment while achieving high measurement precision, reducing the complexity of user operations though adding automated system components.
3Reliability
If multiple defocus factors are calculated using disparity image sensors to adjust focusing lens, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent segments the focus measurement task into multiple independent defocus factors, each calculated from images captured at different focal planes by the disparity image sensor. This segmentation allows the system to measure different aspects of focus quality separately and combine them for more reliable focus determination, improving reliability through diversified measurement approaches.
Solution Approach 2:
The disparity image sensor serves multiple functions: capturing images at different focal planes, providing data for calculating multiple defocus factors, and enabling both automatic focus adjustment and quality assessment. This multi-functionality improves reliability by using the same sensor for multiple measurement purposes while avoiding the need for separate specialized sensors for each function.
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 image clarity and brightness by compensating for temperature-induced focal shifts and manufacturing variances, ensuring sharper virtual images in augmented and mixed reality displays.
Implementation Method 1
dual-photodiode disparity image sensor that generates a second defocus factor in response to an alignment of a first intensity profile of the adjustment image and a second intensity profile of the adjustment image
Implementation Method 2
Optical lenses are used to focus display light and also used to focus image light onto image sensors for imaging purposes. The focus of an optical lens may change with temperature.
Data Source
AI summary
A device includes a display waveguide, a disparity waveguide, and a sensor. The disparity waveguide is configured to receive a portion of image light from the display waveguide. The sensor is configured to capture a measurement of light received from the disparity waveguide.