Off-axis Measurement Optical System for Subjective Optometry
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Solution Overview
Problem
Existing subjective optometry apparatuses fail to objectively and satisfactorily measure optical characteristics of the subject eye due to interference from the optometry unit, as measurement light is reflected on the optical member and detected along with the subject's eye reflections.
Innovation Solution
The apparatus sets the optical axis of the measurement optical system off-axis from the optical axis of the optometry unit's optical member, preventing detection of reflected light from the optical member and allowing for accurate measurement of the subject's eye characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If measurement light is applied to the subject eye through the optometry unit, then the measurement can be performed, but the optical characteristics cannot be objectively and satisfactorily measured due to reflection interference
Solution Approach 1:
The measurement optical system is extracted from the subjective examination optical path. The measurement light is applied to the subject eye through a different path that does not pass through the optometry unit's optical member, thereby eliminating the reflection interference from the optical member while still enabling objective measurement of the subject eye's optical characteristics
Solution Approach 2:
The optical system is segmented into separate measurement and examination paths. The measurement optical system operates independently from the optometry unit's optical path, allowing measurement light to reach the subject eye without passing through the optical member that causes reflection interference during subjective examination
2Device complexity
If the measurement optical system uses the same optical path as the optometry unit, then the device structure is simplified, but the measurement accuracy deteriorates due to detected reflected light from the optical member
Solution Approach 1:
The optical system is divided into separate measurement and examination paths. The measurement optical system uses a distinct optical path from the optometry unit, preventing reflected light from the optical member from entering the measurement system while maintaining reasonable device complexity through integrated design
Solution Approach 2:
The measurement function is extracted from the subjective examination optical path. By separating the measurement light path from the examination light path, the system eliminates measurement errors caused by optical member reflections while preserving the overall device structure
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 enables objective and satisfactory measurement of optical characteristics, such as refractive power, contrast sensitivity, and binocular function, by isolating the subject's eye reflections from the optometry unit's reflections.
Implementation Method 1
measurement light of the measurement optical system is applied to the subject eye... the reflected light of the measurement light reflected on the subject eye... the light receiving optical system receives the reflected light
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
A subjective optometry apparatus includes an optometry unit having an optical member, being located in front of a subject eye, and changing optical characteristics of a target light flus with using the optical member, and a measurement optical system that has a light projecting optical system for applying measurement light emitted from a measurement light source to a fundus of the subject eye through the optometry unit, and a light receiving optical system in which a detector receives reflected light of the measurement light reflected on the fundus of the subject eye through the optometry unit, and that objectively measures the optical characteristics of the subject eye. An optical axis of the measurement optical system is set to be off-axis from an optical axis of the optical member in the optometry unit.