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Laser differential confocal lens refractive index measurement
Weiqian Zhao1, Yun Wang, Lirong Qiu
1Key Laboratory of Photoelectronic Imaging Technology and System (Ministry of Education of China), Opto-Electronic College, Beijing Institute of Technology, Beijing 100081, China. zwq669@126.com
Applied Optics
|August 23, 2011
Summary
A novel laser differential confocal method precisely measures lens refractive index. This technique achieves high accuracy (2.5×10⁻⁴) using aberration compensation and ray tracing for noncontact optical measurements.
Area of Science:
- Optics and Photonics
- Materials Science
- Metrology
Background:
- Accurate refractive index measurement is crucial for lens design and manufacturing.
- Existing noncontact methods face limitations in precision and applicability.
Purpose of the Study:
- To introduce a new laser differential confocal method for high-precision lens refractive index measurement.
- To achieve noncontact measurement with enhanced accuracy.
Main Methods:
- Utilizing the absolute zero of the differential confocal axial intensity curve to identify objective positions.
- Employing aberration compensation and ray tracing facet iterative calculation.
- Implementing a noncontact measurement approach within the light-path.
Main Results:
- The proposed method precisely identifies objective positions with and without the test lens.
- Theoretical analysis and preliminary experiments demonstrate high accuracy.
- Achieved accuracy of approximately 2.5×10⁻⁴.
Conclusions:
- The laser differential confocal method offers a viable approach for high-precision, noncontact lens refractive index measurement.
- The technique overcomes limitations of existing methods by combining precise positioning with advanced optical calculations.
- Further validation through extensive experiments is recommended.
