Eye Refractive Power Measurement Using 850-940 nm Light Source
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing eye refractive power measurement apparatuses face challenges in accuracy due to luminance decrease, light noise, and insufficient light amount, particularly with infrared light sources, which result in low sensitivity and measurement errors.
Innovation Solution
An eye refractive power measurement apparatus utilizing a super-luminescent diode or laser diode as a light source with a center wavelength between 850 nm and 940 nm, combined with a two-dimensional imager device and a prism to reduce speckle noise, projects a focused measurement light onto the fundus and receives a ring-pattern image, allowing for accurate refractive power determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If an infrared LED is used as a light source, then the light source can be compact, but the measurement accuracy deteriorates due to luminance decrease and light noise effect
Solution Approach 1:
The patent changes the wavelength parameter of the light source from conventional infrared (around 780-850 nm) to short-wavelength infrared region (900-1064 nm). This parameter change resolves the contradiction by providing both sufficient luminance for accurate measurement and compact light source dimensions, as the new wavelength range offers better luminous efficiency while maintaining small form factor
2Quantity of substance
If the measurement light diameter is increased, then the light amount increases, but the measurement accuracy worsens due to light noise effect
Solution Approach 1:
The patent changes the wavelength parameter to short-wavelength infrared (900-1064 nm), which provides higher luminous efficiency. This allows obtaining sufficient light amount at the light-receiving element without increasing the measurement light diameter, thereby avoiding light noise effects while maintaining measurement accuracy
3Volume of moving object
If infrared light is used for measurement, then the light source can be compact, but the light-receiving sensitivity is considerably low resulting in light-amount deficiency
Solution Approach 1:
The patent changes the wavelength parameter from conventional infrared to short-wavelength infrared (900-1064 nm). This parameter change resolves the contradiction by selecting a wavelength range where both the light source can remain compact and the light-receiving sensitivity is significantly improved, eliminating light-amount deficiency at the imager device
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 apparatus achieves improved measurement accuracy by minimizing noise and ensuring sufficient light amount, providing precise determination of refractive power with reduced errors, and is less burdensome for patients during ocular characteristic acquisition.
Implementation Method 1
the light source is a super-luminescent diode or a laser diode that emits light having a center wavelength in a range of approximately 850 nm to 940 nm
Implementation Method 2
receives the measurement light reflected from the fundus
Implementation Method 3
a light-projecting optical system that includes a light source and projects measurement light onto a fundus of the patient's eye
Implementation Method 4
a light-receiving optical system that includes an imager device serving as a two-dimensional light-receiving element and receives the measurement light reflected from the fundus
Data Source
AI summary
An eye refractive power measurement apparatus for objectively measuring eye refractive power of a patient's eye, includes: a light-projecting optical system that includes a light source and projects measurement light onto a fundus of the patient's eye; a light-receiving optical system that includes an imager device serving as a two-dimensional light-receiving element and receives the measurement light reflected from the fundus; and an operating section that determines the eye refractive power of the eye based on a two-dimensional pattern image by the measurement light imaged by the imager device. The light source is a super-luminescent diode or a laser diode that emits light having a center wavelength in a range of approximately 850 nm to 940 nm.