Non-contact lens center thickness measurement increases throughput
OptiSurf® LTM
High precision center thickness and sag value measurement of single lenses and doublets
In optics production, the high quality of the single lens is the prerequisite for high-precision optical systems. With the OptiSurf® LTM (Lens Thickness Measurement), TRIOPTICS offers a precise center thickness measurement system for single lenses and doublets that seamlessly integrates into any production process. The high precision low-coherence interferometry is based on the established OptiSurf® technology and measures single lenses and doubles with a glass thickness of up to 150 mm with a precision of ±0,5 µm. The non-contact measurement system is gentle on sensitive surfaces and coatings. In addition to the center thickness, the sag value can also be determined.
The optimization for use in production is particularly evident in its simple and stable handling. The OptiSurf® LTM is equipped with vibration damping and a self-centering mechanical clamping chuck. Two clamping chucks are available to choose from depending on the sample size (standard: 8 mm … 200 mm, micro: 1 mm … 30 mm). This eliminates any adjustment of the sample and the measuring process can be carried out safely, quickly and independently of the operator.
Simple operation is ensured by an integrated touch screen. For a straightforward data input a database can be called up via a network connection. The customer-specific connection of a barcode scanner is possible.
Applications
OptiSurf® LTM allow the measurement of:
Center thickness of lenses
Center thickness of single lenses on an arbor
Overall thickness of doublets and individual thickness of the cemented lenses.
Sag value of concave lens surfaces
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Software
OptiSurf® LTM Software
Simple handling – fast results
Just like the remaining design of OptiSurf® LTM, the software is also optimized for the quick measurement of single lenses as needed for smooth daily usage in optical workshops. The measurement settings are easy to configure and the results are presented in a way that is simple to understand. In addition, a pass/fail analysis of the measurement result is performed.
Technical Data
Parameter | OptiSurf® LTM |
---|---|
Sample diameter | 200 mm, optionally 300mm |
Glass thickness | Up to 50 mm, optionally expandable to 150 mm |
Accuracy of center thickness measurement (geometric thickness) | ± 0.5 µm |
Dimensions (h x w x d) | 560 mm x 500 mm x 350 mm |
Weight | 29.5 kg |
Type | table top device |
Parameter | OptiSurf®LTM LensGage |
---|---|
Max. Sample diameter | 200 mm |
Measurement accuracy | ng: ~10-4 for dgeom > 6 mm dgeom: 1.5 µm |
Maesurement wavelength | 1310 nm; spectral band width of 85 nm |
Thickness range for LensGage Module | Up to 55 mm optical thickness (larger on request) |
Upgrades & Accessories
LensGage module
Knowledge Base
Group refractive index
The OptiSurf® measuring system is used for the non-contact determination of the geometric distance between two surfaces. This is calculated from the measured optical path length (OPL) and the refractive index n of the material.
d = OPL / n
The refractive index n describes the change in the speed of light of monochromatic light in a material compared to the speed of light in vacuum.
Since the refractive index is wavelength-dependent, the propagation speed of monochromatic light differs from that of spectrally broadened light. This results in the so-called group refractive index ng, which can be determined from the refractive index n, according to:
ng (λ) = n (λ) – dn (λ) / dλ
ng Group refractive index
n Refractive index
λ Wavelength
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