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ECE 4616 Deslis
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Introduction• Past Homework solution
• Zemax Examples using Third Order Aberration theory
• Monochromatic Design
• Polychromatic Design
• Homework
ECE 4616 Deslis
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HomeWorkDesign a single lens using Zemax and show performance using Spot Diagrams
•Focal ratio f/5.6
•Glass is N-BK7
•Focal Length is 100mm
•Field of view is 8 degrees
•Central Lens thickness 2mm to 12mm
•Wavelength 632.8nm (HeNe)
•Edge thickness minimum 2mm
•Lens should be optimized for smallest RMS
•Object is at infinity
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HOMEWORKSurface (Radius=R1)
concentric to STOP( B=0)
STOP
Aplanatic surface (Radius=R2)
Δ(u/n)=0
Specifications
EFL=150 mm
F/#=5.6
WL=0.55
Find.
1. Refractive index of lens
2. Radii of lens –use Lens Maker formula
3. Determine which aberrations are present for each surface
R2=R1
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Solution to Homework - 1For the first surface where s1=∞, n=1, n’=μ
Rnn
sn
sn −
+='
''
11
1'1 −=μμRs
For the second surface 11
'12 −=−
−=−=
μμμ RRRRss
Since the second surface is aplanatic then 11'
2 −=
+=
+= μμ
μ RRRn
nns
012 =−− μμ From where we get μ=1.618034
⎥⎦
⎤⎢⎣
⎡ −+−−=
2121
)1(11)1(1RR
dRRf μ
μμ R1=R2=d with f=150 mm we get R=35.4102
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Solution to Homework - 2
(SI)1
0
0
(SIV)1=X
0
0
0
0
(SV)2
Surface1 Surface2
(SIV)2=-X
TOTAL
(SI)1
0
0
0
(SV)2
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ZEMAX SetupAdd F/# (EFL Later)
Set up Units
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Wavelength data
Add Wavelength data
Add FOV
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Zemax Setup
Add Radius for surface 1Add Radius for surface 2 to be equal to Radius of surface 1Add Thickness equal to the radius for surface 1Add a Glass that will be changed later – Start with N-BK7Then Use glass solve and allow index to vary
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Zemax Setup
To make it concentric to the STOP we use s thickness solve where the thickness is always equal to the radius of surface 1
Make the second surface aplanatic by using the aplanatic solve on the second surface
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Zemax Setup
Allow Radius of Surface 1 to vary
Now we have two more things to constrain
1.EFL2.Radius of surface 1 has to be equal to radius of surface 2
These two items will be controlled in the merit function
Find Paraxial focal plane using the thickness solve on surface 2
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Zemax Setup
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The Merit Function Setup
EFFL is set to 150 mm
The two curvatures are set to be the same, by subtracting each other first andThen by multiplying that difference with a large number
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Optimize
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Set up Merit Function for best focusAllow defocus to vary and add rays in the merit function so that we optimize with respect to RMS spot size
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Shift from Paraxial to Best Focus
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Allow for asphericity at pupil
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Two lenses-Monochromatic DesignGlass is N-PSK53A nd=1.61800
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Monochromatic Seidel coefficients
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Add Color
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Move Stop to correct CT
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Stop Shift FormulaeII SS =*
IIIII ESSS δ+=*
IIIIIIIII SEESSS 2* 2 δδ ++=
IVIV SS =*
IIIIVIIIVV SESESSESS 32* 3)3( δδδ ++++=
LL CC =*
LTT ECCC δ+=*
These powerful formulae enable us to calculate the effect of a stop shift on the aberrations of any system.
TOTAL
0
0
0
0
SV
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Add Buried Surfaces
N-PSK3A(620635) and F9(620381) for both doublets
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Modify Merit Function
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Performance of Lens
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Remember Project
Homework due next class
Next Homework covers use of Zemaxand is out on Thursday
Selection: Pick your device. If you have no ideas, look on the website at the old examples or come see me. Duplicates are OK. Ihave topics from work I can suggest if you’re interested. This report should give a brief background on what the device is, what it’s good for etc and (important) a list of the relevant external specs with, where possible, guesses on reasonable values.
DUE: October 15th
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