Eyeglasses-Worn Ocular Refraction Measurement With Angled Illumination
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Solution Overview
Problem
Existing eye refractive power measurement apparatuses face challenges in accurately measuring refractive power in the presence of eyeglasses due to variations in lens curvature and frame fit, leading to insufficient illumination and alignment issues.
Innovation Solution
An eye refractive power measurement apparatus with an illuminating light source positioned 30° or greater relative to the measurement optical axis, outside the ring target projecting optical system, and capable of switching between eyeglasses-worn and eyeglasses-not-worn states, reduces artifacts from eyeglass lenses and facilitates smooth alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the illuminating light source is placed at a small angle (less than 30°) with respect to the measurement optical axis, then the anterior segment can be sufficiently illuminated, but reflected light from the eyeglass lens is included in the anterior segment image
Solution Approach 1:
The patent resolves the contradiction by changing the angular dimension of light source placement. By positioning the illuminating light source at an angle of 30° or more with respect to the measurement optical axis, the system moves the illumination direction to a different angular dimension that avoids the reflection path into the imaging optical system, thereby eliminating lens reflections while maintaining sufficient anterior segment illumination
2Object-affected harmful factors
If only three infrared light sources are used to illuminate the anterior segment, then reflected light from the eyeglass lens is avoided, but the amount of light is insufficient for proper illumination and alignment
Solution Approach 1:
The patent changes the angular parameter of the illuminating light source placement (setting it at 30° or more with respect to the measurement optical axis) to simultaneously achieve two objectives: avoiding lens reflections by changing the illumination angle, and maintaining sufficient illumination intensity by using an optimized light source configuration at this specific angle
3Ease of operation
If the illuminating light source is placed close to the measurement optical axis, then alignment with the examinee's eye is facilitated, but reflected light from the eyeglass lens enters the observing optical system
Solution Approach 1:
The patent resolves this contradiction by utilizing the angular dimension differently. The illuminating light source is positioned at an angle of 30° or more with respect to the measurement optical axis, which is outside the imaging optical system's field of view, thereby preventing lens reflections from entering the observing optical system while still enabling proper alignment through the ring target projection
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
Enables accurate measurement of refractive power in eyeglasses-worn states by minimizing lens reflections and improving alignment, regardless of lens curvature or frame fit, through optimized illumination and mode switching.
Implementation Method 1
an illuminating light source for illuminating the anterior segment of an examinee's eye in an eyeglasses worn state
Implementation Method 2
a measuring optical system for projecting measurement light onto the fundus of an examinee's eye, receiving reflected light therefrom
Data Source
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AI summary
An eye refractive power measurement apparatus is provided which includes a measuring optical system for projecting measurement light onto the fundus of an examinee's eye, receiving reflected light therefrom, and accordingly objectively measuring the eye refractive power of the examinee's eye. The eye refractive power measurement apparatus includes an illuminating light source for illuminating the anterior segment of the examinee's eye in an eyeglasses worn state, the illuminating light source being placed at a position inclined 30° or greater with respect to a measurement optical axis of the measuring optical system, and an observing optical system configured to observe the anterior segment of the examinee's eye in the eyeglasses worn state, the anterior segment being illuminated by the illuminating light source. The eye refractive power measurement apparatus is capable of objectively measuring the eye refractive power of the examinee's eye in the eyeglasses worn state.