Retinal Scan Display Eye Box Segmentation to Prevent Double Images
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Solution Overview
Problem
Existing methods for projecting image content onto the retina using optical systems can result in double images due to variations in the distance between the eye pupil and the redirection unit, causing image distortion.
Innovation Solution
The method employs an optical system with a projector unit, a redirection unit, and an optical segmentation element to project image content via multiple imaging paths, using a MEMS mirror for deflection and holographic elements for redirection, while an image processing device blanks and adjusts image subsets to ensure image content is projected without double images, even with varying pupil positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the distance between the eye pupil and the redirection unit is changed (e.g., by shifting spectacles), then the system becomes more adaptable to different wearing positions, but double images occur because beam bundles fan out outside the exit pupil plane
Solution Approach 1:
The patent divides the exit pupil plane into multiple segmented regions (first exit pupil region and second exit pupil region) and assigns different image data subsets to each region. This segmentation allows the system to maintain reliable single-image display across different pupil positions by ensuring that only one eye box contains active image data for any given pupil location, while still accommodating adaptability to different wearing positions.
2Reliability
If multiple eye boxes are generated to cover the entire pupil region, then complete image content visibility is ensured, but the system complexity increases
Solution Approach 1:
The patent employs dynamic control of image data subsets, where the activation and blanking of different image data subsets is dynamically adjusted based on the detected or assumed pupil position. This dynamic approach allows the system to maintain simple operation by activating only the necessary eye boxes for the current pupil position, rather than permanently maintaining all possible eye boxes, thus ensuring complete image visibility while managing system complexity.
Solution Approach 2:
The patent performs preliminary determination of the pupil position (either through detection or assumption of a reference position) before displaying image content. Based on this preliminary information, the system pre-configures which image data subsets should be active and which should be blanked, ensuring that the correct eye boxes are prepared in advance to cover the pupil region without requiring complex real-time adjustments during image display.
3Reliability
If image data are selectively blanked to prevent double images, then image quality is improved, but the processing complexity increases
Solution Approach 1:
The patent applies local quality control by selectively blanking specific subsets of image data corresponding to specific eye boxes and pupil regions, rather than uniformly processing all image data. The image processing device identifies which local regions (eye boxes) contain active image data and blanks only those subsets that would cause double images for the current or assumed pupil position, thereby improving image quality while minimizing unnecessary processing complexity.
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 ensures clear and distortion-free image projection by generating spatially offset eye boxes, maintaining image visibility and resolution regardless of pupil position, thereby preventing double images.
Implementation Method 1
an optical segmentation element that is arranged between the projector unit and the redirection unit and is designed to project the image content via at least two different imaging paths onto at least one projection region of the redirection unit
Implementation Method 2
an optical replication component, which is arranged in the at least one projection region of the redirection unit and is designed to direct the projected image content onto the eye of the user in a replicated and spatially offset manner, so that a plurality of mutually spatially offset eye boxes with the image content is generated
Data Source
AI summary
A method for projecting image content onto the retina of a user using an optical system. Image data are captured using the image processing device. A first subset of the image data is blanked, thereby generating an active second subset of image data. The first and second subsets make up the total amount of the image data. The projector unit is controlled using the image data such that there is always only one eye box, generated on a common imaging path, with the same active image data arranged in the region of a first pupil region of the user. The first pupil region surrounds the pupil center. A portion of the eye box is arranged with a portion of the active image data within a second pupil region of the user. The second pupil region surrounds the pupil center. The second pupil region is arranged within the first pupil region.