optical design with zemax for phd - basics · 2013. 5. 21. · optical design with zemax for phd -...
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Optical Design with Zemax
for PhD - Basics
Lecture 3: Properties of optical systems II
2013-05-30
Herbert Gross
Summer term 2013
2
Preliminary Schedule
No Date Subject Detailed content
1 02.05. Introduction
Zemax interface, menus, file handling, system description, editors,
preferences, updates, system reports, coordinate systems, aperture, field,
wavelength, glass catalogs, layouts, raytrace, system insertion, scaling,
component reversal
2 16.05. Fundamentals Diameters, stop and pupil,pick ups, solves, variables, ray fans, quick focus,
3D geometry, ideal lenses, vignetting, footprints, afocal systems,
3 23.05. Properties of optical systems I Aspheres, gratings and diffractive surfaces, special types of surfaces,
telecentricity
4 30.05. Properties of optical systems II Ray aiming, Delano diagram, lens catalogs
5 06.06. Aberrations I Representations, geometrical aberrations, spot, Seidel, transverse aberration
curves, Zernike wave aberrations
6 13.06. Aberrations II PSF, MTF, ESF
7 20.06. Imaging Fourier imaging, geometrical images
8 27.06. Advanced handling I Slider, universal plot, I/O of data, multi configurations
9 04.07. Optimization Algorithms, merit function, methodology, correction process, examples
10 11.07. Correction I Principles, simple systems
1. Ray aiming
2. Delano diagram
3. Lens catalogs
4. Afocal and telecentric systems
5. Slider and universal plots
3
Contents
Userdefined diameter at a surface in
the Lens Data Editor (U)
- serves also as drawing size in the
layout (for nice layouts)
- if the diameter of the system stop is fixed, the initial aperture can be computed automatically by
General / Aperture Type /
Float by Stop Size
This corresponds to a ray aiming on the rim of the stop surface. The aperture values in the PRESCRIPTION DATA list then changes with the diameter
A more general aiming and determination of the opening for all predefined diameters is not possible in Zemax
4
Ray Aiming
Delano Diagram
Special representation of ray bundles in
optical systems:
marginal ray height
vs.
chief ray height
Delano digram gives useful insight into
system layout
Every z-position in the system corresponds
to a point on the line of the diagram
Interpretation needs experience
CRyy
lens
y
field lens collimatormarginal ray
chief ray
y
y
y
lens at
pupil
position
field lens
in the focal
plane
collimator
lens
MRyy
Pupil locations:
intersection points with y-axis
Field planes/object/image:
intersectioin points with y-bar axis
Construction of focal points by
parallel lines to initial and final line
through origin
y
y
object
plane
lens
image
plane
stop and
entrance pupil
exit pupil
y
y
object
space
image
space
front focal
point Frear focal
point F'
Delano Diagram
Delano Diagram
Influence of lenses:
diagram line bended
Location of principal planes
y
y
strong positive
refractive power
weak positive
refractive power
weak negative
refractive power
y
y
object space image space
principal
plane
yP
yP
Delano Diagram
Afocal Kepler-type telescope
Effect of a field lens
y
y
lens 1
objective
lens 2
eyepiece
intermediate
focal point
y
y
lens 1
objective
lens 2
eyepiece
field lensintermediate
focal point
Delano Diagram
Microscopic system
y
y
eyepiece
microscope
objective tube lens
object
image at infinity
aperture
stop
intermediate
image
exit pupil
telecentric
Conjugated point are located on a
straight line through the origin
Distance of a system point from
origin gives the systems half
diameter
Delano Diagram
y
y
object
space image
space
conjugate
line
conjugate line
with m = 1
principal point
conjugate
points
y
y
maximum height of
the coma ray at
lens 2
curve of
the system
lens 1lens 2
lens 3
D/2
10
Location of principal planes in the Delano diagram
Triplet Effect of stop shift
Delano Diagram
y
y
object
plane
lens L1
lens L2
lens L3
image
plane
stop shift
y
y
object
spaceimage
space
principal plane
yP
yP
Kepler telescope with field lens
Microscopic illumination
Delano Diagram
y
y
lens 1
objective
lens 2
eyepiece
field lens
intermediate
image
y
source
field
stop
aperture
stopcondenser
collector
Tele system Galilean telescope
Retro focus objective
Delano Diagram
y
y
negative
lens
positive
lens
pupil
image
y
y
negative
lens
positive
lens
pupil
image
Vignetting :
ray heigth from axis
Marginal and chief ray considered
Line parallel to -45° maximum diameter
yya
Delano Diagram
object
pupil
chief ray
marginal ray
coma ray
yyy + y
y
y
maximum height at
lens 2
system polygon line
lens 1
lens 2
lens 3
D/2
Vignettierung :
Delano Diagram
y
y
line of the Delano
diagram
aperture
bundle
y
yradius free of
vignetting
D/2 = 2 y + y
position of the
system surface
maximum height of
the coma ray
MR
CR
Delanos y-ybar diagram
Simple implementation in Zemax
16
Delano Diagram in Zemax
Example:
- Lithographic projection lens
- the bulges can be seen by characteristic arcs
- telecentricity: vertical lines
- diameter variation
- pupil location
17
Delano Diagram in Zemax
telecentric
image
telecentric
object
pupil
largest beam
diameter: surface 19
Dmax/2
1
23456
78
910
11
12
13
1415
16171819
2021
22
2324
2526
27
28
29
3031
32333435
3637
3839
40
41
42
430
smallest
beam
diameter:
surface 25
yMR
yCR
negative
lenses
positive
lenses
Lens catalogs:
Data of commercial lens vendors
Searching machine for one vendor
Componenets can be loaded or inserted
Preview and data prescription possible
Special code of components in brackets
according to search criteria
18
Lens Catalogs
Some system with more than one lens available
Sometimes:
- aspherical constants wrong
- hidden data with diameters, wavelengths,...
- problems with old glasses
Data stored in binary .ZMF format
Search over all catalogs not possible
Catalogs changes dynamically with every release
Private catalog can be generated
19
Lens Catalogs
Image in infinity:
- collimated exit ray bundle
- realized in binoculars
Object in infinity
- input ray bundle collimated
- realized in telescopes
- aperture defined by diameter
not by angle
object at
infinity
image in
focal
plane
lens acts as
aperture stop
collimated
entrance bundle
image at
infinity
stop
image
eye lens
field lens
Object or field at infinity
Angle Aberrations
Angle aberrations for a ray bundle:
deviation of every ray from common direction of the collimated ray bundle
Representation as a conventional spot diagram
Quantitative spreading of the collimated
bundle in mrad / °
perfect
collimated
real angle
spectrum
real beamDu
z
Special stop positions:
1. stop in back focal plane: object sided telecentricity
2. stop in front focal plane: image sided telecentricity
3. stop in intermediate focal plane: both-sided telecentricity
Telecentricity:
1. pupil in infinity
2. chief ray parallel to the optical axis
Telecentricity
telecentric
stopobject imageobject sides chief rays
parallel to the optical axis
22
Double telecentric system: stop in intermediate focus
Realization in lithographic projection systems
Telecentricity
telecentric
stopobject imagelens f1 lens f2
f1
f1
f2
f2
23
Special Cases of Wave Aberrations
3. afocal system
- exit pupil in infinity
- plane wave as reference
4. telecentric system
chief ray parallel to axis
24
yp
z
reference
plane
wave front
image in
infinity
yp
z
y'
reference
sphere
wave front
pupil
planeideal
image
plane
axial
chromatic
1.Telecentric object space
Set in menue General / Aperture
Means entrance pupil in infinity
Chief ray is forced to by parallel to axis
Fixation of stop position is obsolete
Object distance must be finite
Field cannot be given as angle
2.Infinity distant object
Aperture cannot be NA
Object size cannot be height
Cannot be combined with telecentricity
3.Afocal image location
Set in menue General / Aperture
Aberrations are considered in the angle domain
Allows for a plane wave reference
Spot automatically scaled in mrad
25
Telecentricity, Infinity Object and Afocal Image
Slider option in menue: Tools / Miscellaneous / Slider
Dependence of chosen window output as a function of a varying parameter
Automatic scan or manual adjustment possible
Example 1: spot for changing the aspherical constant of 4th order of a lens
Example 2: Optical compensated zoom system
26
Slider
Possibility to generate individual plots for special properties during changing one or two
parameters
Usually the criteria of the merit function are shown
Demonstration: aspherical lens, change of Strehl ratio with values of constants
The sensitivity of the correction can be estimated
It is seen, that the aspherical constants on one side are enough to
correct the system
27
Universal Plot
One-dimensional: change of 4th
order coefficient at first surface
Two-dimensional case: dependence on
the coefficients on both sides
28
Universal Plot
Universal plot configurations can be saved and called later
Useful example: spot diameter as a function of a variable: operator RSCH
29
Universal Plot