Convertible Eye Imaging with a Unity-Magnification Afocal Relay
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Solution Overview
Problem
Existing optical systems for ocular imaging, particularly those based on mobile devices, face challenges such as inability to provide optical conjugation, insufficient field-of-view, severe residual aberrations, and limited adaptability for imaging both posterior and anterior eye surfaces, often resulting in complex and expensive designs.
Innovation Solution
A portable optical system comprising a first lens system housed in a mobile device and an afocal relay with two identical lenses that form a conjugate relationship, allowing for interchangeable imaging of posterior and anterior eye surfaces with unity magnification and diffraction-limited performance, using a simple and cost-effective design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a slit-lamp-based optical system with an ophthalmic lens is used to image both anterior and posterior portions of the eye, then imaging capability is improved, but device complexity and manufacturing cost increase significantly
Solution Approach 1:
The patent implements a single optical system that can image both anterior and posterior portions of the eye by using a removable lens assembly. The lens system is designed to be interchangeable between two configurations: one for anterior segment imaging and another for posterior segment/fundus imaging. This universal design eliminates the need for separate slit-lamp and fundus camera systems, reducing overall device complexity while maintaining versatile imaging capability.
Solution Approach 2:
The optical system is divided into separable components: a fixed lens system in the mobile device and a removable lens assembly that can be attached or detached. This segmentation allows the system to switch between imaging modes by simply changing the lens assembly, rather than requiring a completely different optical path for each imaging type. The segmentation principle reduces the complexity of the overall system architecture.
2Adaptability or versatility
If traditional ophthalmic lenses are added to the slit-lamp system for fundus imaging, then posterior chamber imaging is enabled, but chromatic aberrations and optical performance deteriorate
Solution Approach 1:
The patent merges the anterior segment imaging lens and the fundus imaging lens into a single integrated removable lens assembly. Both lens configurations are designed with complementary optical characteristics that work harmoniously with the fixed lens system in the mobile device. The merging of design considerations for both imaging modes into a single lens assembly ensures consistent optical performance and minimizes chromatic aberrations across both anterior and posterior segment imaging.
Solution Approach 2:
The patent employs parameter changes in the lens design, specifically using different optical powers and focal lengths for the anterior and posterior segment lenses. The removable lens assembly includes a first lens with optical power between +20D to +60D for anterior imaging and a second lens with optical power between +50D to +100D for fundus imaging. These parameter changes are optimized to maintain diffraction-limited performance and minimize chromatic aberrations in both imaging modes.
3Ease of operation
If mobile device-based fundus cameras are used, then portability is improved, but field-of-view and optical conjugation are insufficient
Solution Approach 1:
The patent uses asymmetric lens designs where the removable lens assembly is optimized for specific imaging geometries. The lens shapes and curvatures are asymmetrically configured to maximize the field-of-view for fundus imaging while maintaining optical conjugation with the mobile device camera. The asymmetric design allows the system to achieve a wide field-of-view (50-60 degrees) despite the compact mobile device form factor.
Solution Approach 2:
The patent addresses the field-of-view limitation by introducing angular dimension optimization in the lens design. The removable lens assembly is configured to capture light rays from a wide angular range and redirect them to the mobile device camera sensor. This dimensional approach to light routing enables a wide field-of-view in a compact portable system, overcoming the inherent limitations of mobile device-based imaging.
4Ease of operation
If existing mobile device optical systems are used for ocular imaging, then portability is improved, but residual aberrations and imaging quality worsen
Solution Approach 1:
The patent uses a high-quality optical reference design from traditional ophthalmic instrumentation and replicates its optical performance characteristics in the removable lens assembly. By copying the proven optical design principles and lens configurations from slit-lamp and fundus camera systems, the patent achieves diffraction-limited imaging quality in a portable mobile device platform. The lens assembly is designed to reproduce the optical performance of traditional instruments while maintaining portability.
Solution Approach 2:
The patent optimizes imaging quality by carefully selecting and adjusting optical parameters of the removable lens assembly. The lens materials, curvatures, thicknesses, and spacing are precisely controlled to minimize spherical aberration, coma, and chromatic aberration. The optical power and focal length parameters are optimized to achieve diffraction-limited performance across the visible spectrum, ensuring high imaging quality despite the compact portable form factor.
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 system achieves diffraction-limited imaging with wide field-of-view, minimizing manufacturing costs and operational complexity, enabling easy reconfiguration between posterior and anterior eye imaging modes without chromatic aberrations.
Implementation Method 1
an afocal relay including first and second lenses that possess equal optical properties, the afocal relay configured to have a unity magnification and to provide diffraction-limited imaging
Implementation Method 2
provide diffraction-limited imaging within a spectral range from at least 486 nm to at least 656 nm
Implementation Method 3
a first lens system of an first optical system housed in a body of a mobile telecommunication device, said first lens system having a first optical axis
Data Source
AI summary
An reconfigurable optical arrangement for imaging posterior and anterior surfaces of a visual system. The optical arrangement includes a relay containing first and second lenses each having a positive optical power and detachably cooperated with one another such that the first lens and the second lens form an afocal system configured to form a conjugate relationship between the first plane and the second plane. In a related embodiment, the optical arrangement may include a first lens system of an first optical system housed in a body of a mobile telecommunication device and an afocal relay including first and second lenses that possess equal optical properties. Here, the afocal relay is configured to have a unity magnification and to provide diffraction-limited imaging within a spectral range from at least 486 nm to at least 656 nm. The method for imaging with the use of the optical arrangement.