Ophthalmologic Apparatus Diopter Correction Focus Detection
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Solution Overview
Problem
Existing ophthalmologic apparatuses face prolonged focus detection times when diopter correction lenses are inserted, as they require searching for a peak evaluation value, which lengthens the focusing process, especially for highly myopic or hyperopic eyes.
Innovation Solution
An ophthalmologic apparatus and method that includes a diopter correction unit with convex and concave lenses, a focus index projection unit, and a system control unit to determine if a diopter correction lens is needed, allowing the focusing lens to move to a predetermined position and insert the appropriate diopter correction lens into the optical path, thereby reducing the time required for focus detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If focus detection is performed using contrast method after diopter correction lens insertion, then focusing can be achieved for highly myopic or hyperopic eyes, but the focus detection time becomes significantly longer
Solution Approach 1:
The system performs preliminary focus detection using focus index images before diopter correction lens insertion to predict the required focusing amount. This preliminary action allows the system to pre-calculate the focusing position, so when the diopter correction lens is inserted, the focusing lens can be directly positioned at the predetermined location without time-consuming contrast search, thus resolving the time delay while maintaining focusing capability
Solution Approach 2:
The patent introduces focus index images as an intermediary tool for preliminary focus detection. These focus index images serve as a mediator that enables the system to obtain focus information before lens insertion, which then guides the subsequent focusing operation after diopter correction lens insertion, avoiding the need for slow contrast-based search
2Measurement precision
If focusing lens is driven to search for peak evaluation value, then accurate focus can be detected, but the focusing process takes longer time
Solution Approach 1:
The system performs preliminary focus detection using focus index images to calculate the predicted focusing amount before actual focusing. This preliminary calculation provides an accurate starting position, eliminating the need for slow peak-searching while maintaining focus detection accuracy
Solution Approach 2:
The patent replaces the mechanical peak-searching process with an optical calculation method using focus index images. Instead of physically driving the focusing lens through a search range to find the peak contrast point, the system uses optical principles to calculate the optimal focus position directly from focus index image analysis, significantly improving focusing speed while maintaining accuracy
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 solution enables faster focus detection and completion, preventing the lengthening of focusing time even for highly myopic or hyperopic eyes, allowing for quicker transition to imaging without the need for extensive peak evaluation searches.
Implementation Method 1
automatic focusing system using a positional relationship between two focus index images obtained by return light of divided focus indexes projected onto a fundus of a subject's eye
Implementation Method 2
If a subject's eye is highly myopic (near-sighted) or highly hyperopic (far-sighted), it is known that a diopter correction lens is inserted into an observation imaging optical system
Data Source
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AI summary
An ophthalmologic apparatus includes a focusing lens provided in an optical path connecting a subject's eye and an imaging unit, a diopter correction lens provided in the optical path to be insertable and removable, and a position determination unit configured to determine a position of the focusing lens on the optical path in a state where the diopter correction lens is inserted, based on an in-focus state where the diopter correction lens is not inserted.