Refractometer Optics Using 2D Sensing for Compact Accurate Measurement
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Solution Overview
Problem
Existing refractometers face challenges in miniaturization and accuracy due to the need for large linear sensor arrays and sensitivity to ambient light, which are exacerbated by the requirement for a wide measurement range and high precision, leading to increased costs and installation complexities.
Innovation Solution
A refractometer design incorporating a lens module to decouple emitting position and direction of optical beams using a two-dimensional array sensor, allowing self-calibration and enabling the use of a smaller, less costly CMOS sensor, and employing a second medium for temperature compensation to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a slit is used to decouple emitting position and direction of optical beams, then the incident angles of optical beams on the photosensitive linear array can be defined, but the size of the photosensitive linear array becomes very large
Solution Approach 1:
The patent transitions from a one-dimensional linear array to a two-dimensional array sensor. This dimensional change allows the system to capture both the angular information (for incident angle definition) and positional information (for beam direction) simultaneously, eliminating the need for a large slit-based one-dimensional array while maintaining measurement precision.
Solution Approach 2:
The two-dimensional array sensor serves multiple functions: it acts as both the light detector and the angular resolution element. By combining the functions of the slit (angular selection) and the linear array (light detection) into a single two-dimensional sensor, the patent reduces the overall system size while maintaining the ability to define incident angles precisely.
2Adaptability or versatility
If a large measurement range of refractive index is required, then the divergence angle of outgoing light must be larger, but the size of the photosensitive linear array must be increased
Solution Approach 1:
By using a two-dimensional array instead of a one-dimensional linear array, the patent achieves wide angular coverage (for large refractive index measurement range) without proportionally increasing the sensor area. The second dimension allows the sensor to capture light from a broader range of angles while maintaining compact form factor.
3Measurement precision
If clear water calibration is performed before measuring liquids, then measurement accuracy can be ensured, but the process requires additional time and steps
Solution Approach 1:
The system performs self-calibration by automatically detecting the refractive index of the liquid being measured and using that information to adjust the measurement parameters. The two-dimensional array sensor captures the light distribution pattern, and the processor automatically determines the calibration state without requiring external clear water calibration, thereby maintaining accuracy while eliminating the time-consuming calibration step.
4Ease of manufacture
If a linear array sensor is used, then cost can be reduced, but the sensor is easily affected by ambient light and mechanical deviations
Solution Approach 1:
The two-dimensional array provides additional spatial information that can be used to distinguish between light from the sample and ambient light. By analyzing the angular distribution of light across the two-dimensional sensor, the system can filter out ambient light interference and mechanical deviations, improving measurement stability while maintaining the cost-effectiveness of array sensor technology.
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 design achieves miniaturization, reduces costs, enhances accuracy, and improves measurement robustness against ambient light interference, enabling precise refractive index measurements across varying temperatures and liquid conditions.
Implementation Method 1
a lens module configured to converge reflected optical beams from the reflecting module onto a focal plane of the lens module
Implementation Method 2
an array sensor located on the focal plane and configured to detect received optical beam and generate a detection image
Implementation Method 3
a processor configured to identify a first stripped area where distinct brightness discontinuity caused by TIR of the first optical beam locates in the detection image
Data Source
AI summary
A refractometer and a method for measuring refractive index is disclosed. The refractometer comprises a light source, a reflecting module, a lens module, an array sensor, and a processor, wherein the reflecting module is configured to receive optical beams from the light source, the reflecting module comprises a detection surface configured to totally reflect at least part of the optical beams; the lens module is configured to converge optical beams from the detection surface onto a focal plane of the lens module; and the array sensor is located on the focal plane of the lens module.