Calendar

Introduction to CODE V
March 19-23, 2007
Pasadena, California
Click here for details and to enroll

Advanced Topics in CODE V
March 26-30, 2007
Pasadena, California
Click here for details and to enroll

LightFair 2007
Booth 200
May 8-10, 2007
New York, New York
http://www.lightfair.com

SID 2007
Booth 1400
May 20-25, 2007
Long Beach, California
http://www.sid.org

Optics and Photonics
Aug. 26-30, 2007
San Diego, CA
http://spie.org

LED 2007
Oct. 24-26, 2007
San Diego, CA

Quick Tip –Obtaining More Precise DN/DT Values for use in CODE V’s Environmental Analysis (ENV)

By default, CODE V assumes your optical designs will be used at room temperature (20º C) and at sea level (760 mm Hg).  However, optics can be subject to temperature and pressure changes which can affect their performance.  CODE V’s Environmental Analysis (ENV) allows you to predict performance degradations due to these changes.  ENV will modify your lens model to account for expansions and contractions of the elements and mounts and index changes that are caused by environmental affects. 

When modeling index changes, ENV uses lookup tables in CODE V’s glass catalog to determine the DN/DT values for the materials in your model.  These lookup tables provide DN/DT values at specific wavelengths and range of temperatures, when available.  For most glasses, DN/DT values are provided at 6 discrete wavelengths across the range of 20º C to 40º C.  Interpolation is performed for wavelengths between these 6 discrete points, but a single DN/DT value for these wavelengths is provided for the entire temperature range.  While this may be accurate enough for many simulations, users sometimes require more accuracy within this range, or may wish to model temperature changes outside the 20º C to 40º C range.  Users can override the use of the DN/DT lookup tables in ENV by entering specific DN/DT values at each wavelength.  To assist in this, the ORA Technical Support Team has written a new macro, DNDTCALC.SEQ, that can be used to calculate more precise DN/DT values, including values outside the 20º C to 40º C temperature range.

Rather than using a look up table, the DNDTCALC macro uses formulas and coefficients provided by Schott and Ohara for more precise calculations of DN/DT values.  Users can request a list of specific DN/DT values, or create a command sequence that can be used in ENV to define DN/DT values.  A copy of the DNDTCALC macro can be downloaded from www.oraservice.com, under CODE V Support > Macros and User-defined Feature Downloads > Macros from ORA Tech Support.  For more details on using this macro, please refer to the comments included in the macro header.

Additional information on using the ENV option can be found in the CODE V Reference Manual, and on ORA’s customer area of the web under Training Materials > Advanced Topics.

Updates to ORA's Customer Service Web Site

The following additions have been recently made to ORA's Customer Service area of the web, www.oraservice.com under CODE V Support:

• The DNDTCALC macro referenced in this month’s Quick Tip is available for download under Macros and User-defined Feature Downloads > Macros from ORA Tech Support.

• New FAQs on using multilayer (MUL) coatings in CODE V have been added to Tech Support FAQs.

• The January 2007 issue of CV Enews, which featured a tip determining the best CODE V algorithm for your needs, is available for download under CODE V Enews & Tips.