Off-Axis Iris Imaging Unit for Ophthalmic Devices
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Solution Overview
Problem
Existing ophthalmic imaging devices face challenges in achieving accurate iris imaging due to off-axis cameras not having their focal plane coincide with the iris plane, leading to reduced light availability and increased complexity with beam splitters, which compromises the optical design and increases device size.
Innovation Solution
An ophthalmic imaging device with an on-axis measuring unit and an off-axis iris imaging unit, where the off-axis unit is arranged at a predetermined angle to the measurement axis, allowing its focal plane to coincide with the iris plane, eliminating the need for additional beam splitters and enhancing the compactness and optical design of the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an off-axis camera is arranged to image the eye, then the device can capture iris images, but the focal plane does not coincide with the iris plane leading to reduced image quality and increased complexity
Solution Approach 1:
The patent transitions from a conventional on-axis camera arrangement to an off-axis camera arrangement positioned at a predetermined angle (e.g., 45 degrees) relative to the measurement axis. This dimensional change in camera positioning allows the focal plane to coincide with the iris plane, improving iris imaging accuracy while eliminating the need for additional beam splitters and reducing optical system complexity
2Adaptability or versatility
If beam splitters are used to direct light to multiple measuring units, then multiple measurements can be achieved, but light availability is reduced and device size increases
Solution Approach 1:
The patent extracts and removes the beam splitter component from the optical system by repositioning the camera off-axis. This eliminates the light loss associated with beam splitters while maintaining the capability to capture iris images, thereby improving light availability for downstream measuring units without sacrificing multi-measurement capability
3Measurement precision
If beam splitters are used to accommodate off-axis imaging, then iris imaging is enabled, but the optical design is compromised and space requirements increase
Solution Approach 1:
The patent positions the camera at an off-axis angle (e.g., 45 degrees) relative to the measurement axis, changing the spatial dimension of camera placement. This allows the camera to capture iris images with proper focus without requiring additional beam splitters or increasing device volume, as the off-axis position naturally aligns the focal plane with the iris plane
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
This configuration allows for a more compact on-axis measuring unit with improved optical design, providing high-resolution iris images and reducing distortion through processing units that correct for optical and geometric distortions, enabling precise iris imaging and characterization of the eye.
Implementation Method 1
The off-axis iris imaging unit comprises an optical system oriented relative to the image plane such that a focal plane of the off-axis iris imaging unit substantially coincides with an iris plane of the iris of the eye
Data Source
AI summary
Disclosed is an ophthalmic imaging device comprising an on-axis measuring unit and an off-axis iris imaging unit, the off-axis iris imaging unit arranged at a predetermined angle to a measurement axis of the ophthalmic imaging device and comprising a sensor defining an image plane, and an optical system oriented relative to the image plane such that a focal plane of the off-axis iris imaging unit substantially coincides with an iris plane of the iris of the eye.