Assignment Commands

Assignment commands are ones that assign values to internal data. If you want to know the command for assigning a particular item of data in a lens, you can use the menus to accomplish this, then save the file and look at it using a text editor. The listing below shows the file lasrdb1.len file corresponding to the doublet lens example.

A lens file is just a text file containing commands. You can enter lenses by creating lens files off line using a text editor, and then opening them in OSLO. The file below is relatively simple. It consists of a general header line, followed by a line that begins "LEN NEW", and then several lines with the actual lens data. The NXT command indicates that the following data pertains to the next surface. The last line of the main lens file is END, followed by the image surface number. Lenses that have multiconfiguration data or optimization data have additional sections added to them.

// OSLO 5.00 31567     0     0
LEN NEW "He-ne f/2 doublet focusing lens" 60 5
EBR  15.0
ANG  0.0000572957795
DES  "OSLO"
UNI  1.0
SNO1 "This is the completed Lens entry Doublet lens example from the User Guide."
SNO2 "Note that variables and operands have not yet been introduced."
AIR
TH   1.0e+20
AP  9.9999999977e+13
NXT
GLA LASF35
RD   100.0
TH   5.0
NXT
AIR
TH   1.0
NXT
PK  GLA  -2
RD   50.0
TH   5.0
NXT
AIR
PU   -0.25
PY   0.0
NXT
AIR
CALLBACK  1
GPRT On
WV 0.6328
WW 1.0
END  5

The lens input scheme shown above is handled by the L module in OSLO. There is a separate, parallel input scheme called global editing, in which the same commands are used, but a surface number is added as the second argument of surface data. If you want to change the glass on surface 1 to BK7, for example, you could enter gla 1 bk7 directly, eliminating the LEN NEW … END protocol that serves to invoke module L.

The table below summarizes the most common lens data commands. Of course, there are hundreds more that can be found in lens files and/or the help system.

Cmd	Action
cv	Curvature
rd	Radius of curvature
th	Thickness
ap	Aperture
gla	Glass
air	Air
rfl	Reflector
cc	Conic constant
py	Axial ray height solve
pu	Axial ray angle solve
pyc	Chief ray height solve
puc	Chief ray angle solve
pk	Pickup
ebr	Entrance beam radius
nao	Numerical aperture in object space
obh	Object height
ang	Field (half) angle
lid	Lens identification
ast	Aperture stop surface
ims	Image surface
wv_	Wavelength (with number suffix)
ww_	Wavelength weight (with number suffix)
uni	Units
des	Designer

In addition to lens surface data and operating conditions, lens files contain optimization-related data. There are several single-letter commands that allow you to enter such data easily, as follows:

You may wish to use a command just to open a spreadsheet, and then enter data through the spreadsheet. The next table shows the commands for opening the principal spreadsheets.

Cmd	Action
lse	Opens the surface data spreadsheet
pse	Opens the paraxial data spreadsheet
cse	Opens the configuration data spreadsheet
vse	Opens the variables spreadsheet
fse	Opens the field point spreadsheet
rse	Opens the ray set spreadsheet
ose	Opens the operands spreadsheet
tse	Opens the tolerance data spreadsheet
uoc	Opens an operating conditions spreadsheet
wse	Opens the wavelengths spreadsheet
gbm	Opens the Gaussian beam spreadsheet

Cmd	Action
c	Configuration data
f	Field point
r	Ray in ray set
o	Operand
v	Variable