Application Notes – Custom Designed Systems, Vol. 10Spectral Analyzer for Film Thickness Determination of Optical
Filters by Combined Transmittance and Reflectance Measurements
PartnerThe instrument was developed and manufactured for Prinz Optics
GmbH, a subsidiary of the PRINZ GROUP. Prinz Optics is a supplierof light guides and dichroic coatings for the filtering and reflecting oflight. Prinz Optics carries out a 100 % final inspection to ensure thehigh quality demands and to achieve that the standards according toDIN EN ISO 9001 are being met. The tec5 UV/VIS/NIR spectrometersystem is used for production control and the final inspection of the
optical filters and performed for 2 years now without any problem.

Application
The optical filters are produced using a wet-chemical coating procedure (Sol-Gel Dip CoatingProcess). Filter systems with up to 19 layers are produced, with product tolerances better than ± 2 nm
for each layer. Because of a continuous reaction in the alcoholic solutions, it is necessary for processcontrol to perform several film thickness measurements per day. There is a linear relationship between
film thickness and withdrawal speed.

Spectrometer System
The measurement setup is based on a tec5 MultiSpec systemusing a Zeiss MCS spectrometer module and a deuterium /halogen shine-through light source covering the spectral rangeof 200-1000 nm. It is equipped with a special designed opticalunit to perform transmittance measurements on plain samples
under an angle of incidence from 0° or 45° and reflectancemeasurements under 0° in milliseconds. The film thickness iscalculated iteratively. Long-term stability is checked once a daywith a special zirconium film test sample, which shows that thesystem reproducibility is better ± 1nm for film thicknessdetermination.
Small filters can be placed into a sample holder inside ameasurement chamber. For production control also filters withbigger dimensions has to be measured non -destructively. A
special design allows to insert the panes directly into a slit.

株式会社

スペクトラ・コープ〒164‑0011 東京都中野区中央4‑4‑5第一小林ビル
Tel:03‑5328‑2858 Fax:03‑5328‑2859
URL http://www.spectra.co.jp

Application Notes – Custom Designed Systems, Vol. 10

SoftwareA special application software was written under Visual Basic on basis of the tec5 function library forspectral data acquisition and processing. The following special functionality was implemented:
dynamic switching of the optical channels for reflectance and transmittance measurements
color determination with 10 standard illuminants predefined and choice of
2° or 10° standard observation
custom module for film thickness determination
2 user levels for operation and administration
special data archiving functionality
linear regression functionality for the calculation and extrapolation of withdrawal speed vs. film
thickness

Spectrum of filter type FS yellow 515

SupportBy working closely with our customers and according to their application specific experience, wedevelop and produce custom designed components, (sub)assemblies or complete instrumentation formany different optical measurement tasks with the emphasis on 'optical spectroscopy'.
tec5 offers the performance of all hardware and software related functions:§§§§Contract development
Instrument conception, design and development
Functional units / prototyping
Serial production

For more information please contact:
Steffen Piecha
tec5 AGIn der Au 25
61440 Oberursel
Deutschland / Germany
Tel.: +49-6171-9758-0
FAX: +49-6171-9758-50
Email: info@tec5.com
www.tec5.com