User’s Guide

Optical glass manufacturers provide detailed technical data for optical glasses via Excel spreadsheets. The opticalglass package provides uniform access to data from different vendors.

Note

The spreadsheets containing the glass data are from the vendor websites. The vendors retain all ownership and copyrights to that data.

Installation

To install opticalglass using pip, use

> pip install opticalglass

Alternatively, opticalglass can be installed from the conda-forge channel using conda

> conda install opticalglass --channel conda-forge

Glass Map Application

A desktop application is installed as part of opticalglass. It is invoked by running glassmap at the command line.

> glassmap

On a Windows machine, the glassmap command will be located in a Scripts directory underneath the install directory. For example, if using a virtual environment named optgla, the command would be

> optgla\Scripts\glassmap

As you hover over the glasses in the map, a pop-up list shows which glasses are under the cursor. Clicking on a glass or glasses in the map will list the glasses and their catalog plus index, V-number and partial dispersion in the table at the right. You can drag glasses from the table and drop the glass, catalog pair on the command line, e.g. as input for the create_glass function.

_images/RefractiveIndex.png

Partial dispersion data can be displayed by clicking on the plot type in the upper right hand panel. Partials may be displayed for one of several different wavebands by making the choice in the Partial Dispersion box.

_images/PartialDispersion.png

Display of different catalogs can be controlled by selecting or unselecting checkboxs in the Glass Catalogs panel on the right.

_images/BuchdahlCoefficients.png

The Buchdahl Dispersion Coefficient display can be used to find glass pairs that can be corrected at 3 wavelengths. Robb and Mercado showed that glasses lying along the same vector from the origin of the dispersion diagram would be color corrected at 3 wavelegths.

_images/BuchdahlDispersion.png

Python Data Model

Two families of objects are provided to manage access to glass data. The GlassCatalogPandas base class manages the generic operations on the catalog. The catalog data is maintained in a DataFrame, accessible via the attribute df. The catalog-specific subclasses of GlassCatalogPandas provide specific mapping information for the vendor spreadsheet format.

The GlassPandas base class manages the generic operations on the individual glass instances. These include refractive index interpolation using either the calc_rindex() or the rindex() methods. The meas_rindex() method, with a spectral line argument, e.g. ‘d’, ‘F’, ‘C’, will return the measured index data from the catalog. The transmission_data() method returns transmission data (10mm sample thickness) for the glass instance.

A factory interface to GlassPandas creation is the function create_glass() that returns a GlassPandas instance of the appropriate catalog type, given the glass and catalog names.

A Glass Map display can be created using the glassmap module. Lists of glasses as well as catalog names can be used to populate the map, using the GlassMapDB class. That is used as input to the GlassMapFigure class that creates the glass map plot.