Spectral Interferometry Apparatus for Portable Eye Length Measurement
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Solution Overview
Problem
Current spectral low coherence interferometry systems for measuring optical path differences are bulky, costly, and require computational power, making them unsuitable for portable and low-cost applications such as industrial measurements and ophthalmology, where they are needed for tasks like eye length measurement.
Innovation Solution
A spectral interferometry method and apparatus that measures optical path differences using a minimal setup without digital displays or computational power, utilizing sound or light indicators to adjust for maximum signal intensity, allowing for portable and cost-effective measurements by adjusting a length device until a specific sound frequency or light intensity is reached, using a broadband source, linear array, or tunable narrow band source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spectral low coherence interferometry systems use standard methods with photodetector linear arrays and FFT processing, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts and removes the FFT processing component and digital display requirements from the system. By using a swept source to directly scan the channelled spectrum and displaying it on an oscilloscope, the system eliminates the need for complex computational processing while maintaining measurement precision through direct spectral observation.
Solution Approach 2:
The patent replaces expensive, complex computational systems with simpler, more affordable components. The use of a swept source combined with direct oscilloscope display substitutes for costly FFT processors and high-end digital display systems, making the apparatus more accessible for portable and clinical applications.
2Measurement precision
If spectral low coherence interferometry systems use standard methods with processors and PC displays, then measurement precision is improved, but device size and weight increase
Solution Approach 1:
The patent removes the PC and heavy processing components from the system. By using a swept source to directly generate and display the channelled spectrum on an oscilloscope, the system achieves the same measurement precision without the weight burden of computational hardware.
3Measurement precision
If spectral low coherence interferometry systems use standard methods with FFT processing, then measurement precision is improved, but cost increases
Solution Approach 1:
The patent replaces expensive FFT processing hardware and PC-based systems with more affordable components. The swept source directly scanning the spectrum and displaying it on an oscilloscope provides a cost-effective alternative that maintains measurement precision while reducing system cost for portable and clinical use.
4Measurement precision
If spectral low coherence interferometry systems use standard methods with digital displays, then measurement precision is improved, but ease of operation in complex environments decreases
Solution Approach 1:
The patent introduces an acoustic intermediary by converting the optical measurement signal into audible sound through a loudspeaker. This allows operators to perceive measurement data through hearing rather than sight, enabling operation in visually complex environments such as operating rooms where visual attention is occupied by surgical tasks.
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, portable, and cost-effective measurement of optical path differences without the need for complex computational systems, suitable for industrial and ophthalmological applications, with improved accessibility and reduced size and weight.
Implementation Method 1
spectral low coherence interferometry (LCI) methods are based on the measurement of periodicity of the channelled spectrum of the optical signal coming from a two beam interferometer
Implementation Method 2
employing a dispersing element, such as a prism or a diffraction grating, to disperse respectively diffract light
Implementation Method 3
to disperse respectively diffract light on a linear photodetecting camera to transduce the channelled spectrum of the interferometer output into a temporal signal
Data Source
AI summary
A spectral interferometry apparatus and method are disclosed, that can be used to monitor or measure an unknown length by following a characteristic of an indicating signal. The measurement is performed by adjusting an optical path difference (OPD) in an interferometer part of an interferometer configuration until sound or light or both are obtained with the desired strength and pitch. Embodiments are presented where the unknown length is the eye length. Spectral interrogation of the interferometer optical output is achieved by reading the signal of an analogue photodetector array in a spectrometer or by tuning a swept source and processing the signal of a photodetector. Sound of different pitches are produced either directly in this process, or by using a nonlinear amplifier, or a mixer. For enhanced signal, the array may be driven by a nonlinear clock or the swept source may be driven by a distorted driving signal.