Tolerated intervals for integral quantities

Design targets for color values or other integrated spectral values may not always be well-defined numbers. You can also search for designs where color values stay within tolerated boundaries, but it does not matter where exactly.

Such design situations can be handled in CODE using so-called ‘penalty shape functions’. However, the use of this concept turned out to be rather complicated.

We have now (starting with version 5.02) introduced a very easy definition of tolerated intervals for integral quantities: Instead of typing in the target value you can define an interval by entering 2 numbers with 3 dots in between, like ’23 … 56′ or ‘-10 … -8’. If the integral value lies within the interval its contribution to the total fit deviation is zero. Outside the interval the squared difference between actual value and closest interval boundary is taken, multiplied by the weight of the quantity.

WOSP-UVIS

Based on the WOSP-LEDO light source we have developed a spectrometer system that can be used to measure reflectance spectra in the wavelength range 270 … 900 nm. The light source is based on LEDs only.

2 array spectrometers (not shown in the images) are used to record the sample signal and a reference signal at the same time. This makes the results independent of light source drifts.

Samples must be positioned within a few mm distance to the sample port of the system. The measured spectra are tolerant against small sample tilts or height differences.

Spectral quality is the same as for WOSP-LEDO. The unit can be used as a light source for transmittance measurements as well.

The system requires an external power supply of 12 V DC.

Introducing MIPSS for parallel computing

Due to the nice competition of AMD and Intel computers with many cores become more and more affordable. Unfortunately, our software products SCOUT and CODE use only one core at a time up to now. In order to benefit from increased computing power of modern processors we have implemented MIPSS which means Multiple Instances for Parallel Spectrum Simulation.

MIPSS can be used to significantly speed up batch control computations. We have published a video tutorial that shows how to do this.

In addition, a new mechanism called ‘Bulk analysis’ has been implemented both in SCOUT and CODE. It is applied when a large number of spectra need to be processed in a short time. A tutorial video about bulk analysis is in preparation.

Leng model for optical constants

We have implemented (starting with object generation 4.99) the Leng oscillator which has been developed to model optical constants of semiconductors. As shown in the original article (Thin Solid Films 313-314 (1988) 132-136) it works well for crystalline silicon:


Warning: While the model works fine in the vicinity of strong spectral features (critical points in the joint density of states) it may generate non-physical n and k values in regions of small absorption.

Error messages in OLE automation

In object generation 4.97 we have implemented a new mechanism to pass error messages from SCOUT and CODE to OLE automation clients.

While it runs the OLE server (i.e. SCOUT or CODE) collects error messages in a list. We have introduced a view object (type ‘Error messages view’) to display the current list of error messages in a view.

Any OLE client (LabView, Excel, …) can retrieve information about the number of error messages, their type and text content. There is also a classification to separate critical errors and warnings. Once the OLE client has finished error handling it can clear the list in the OLE server.

WOSP-LEDO – a new UV-Vis light source based on LEDs only

Our new WOSP-LEDO light source generates a homogeneous area of light emission, covering the spectral range 270 … 900 nm. It uses LEDs only – small power, long lifetime.

You can point a collimated field of view of an array spectrometer to the center of the light source and record transmittance or reflectance spectra in lab quality, within a fraction of the time a lab instrument would need.

The following transmittance spectra (100%, 0%, Schott Borofloat glass) have been recorded in less than 1 second, with a distance of about 1 m between light source and detector:

Zooms into the 0 and 100 percent spectra show excellent spectral quality: