Importance

Loading Importance Indicators...

Abstract

Optical measuring apparatus for determining chromaticity of thin films on a substrate includes a light source for illuminating the substrate and a measuring apparatus for dispersing light into various wavelengths and making wavelength dependent intensity measurements. Radiation from the light source is reflected or transmitted by the substrate to the measuring apparatus along a first beam path having a first diaphragm for cutting off the radiation from the substrate in a leak-tight manner. Radiation from the light source is also transmitted to the measuring apparatus directly along a second beam path having a second diaphragm for cutting off radiation from the light source in a leak-tight manner. The light source (6a) consists of a globe photometer (6a), in which a lamp (4) is provided. A steadily burning light source, especially a halogen lamp, is used as the lamp (4). Long-term instabilities are corrected essentially by means of a white reference standard, whereas short-term instabilities are corrected under consideration of the characteristic emission spectrum of the selected lamp (4). For determining the chromaticity of reflecting and transparent thin-film layers applied to substrate, a process for reflectance curve determination is used, in which apparatus-related instabilities interfering with the chromaticity measurement are corrected by normalization of the measured relative spectral energy distributions to the current measurement light spectrum and by taking into consideration the effects of foreign light on the measurement light spectrum.

Loading the Abstract Image...

First Claim