Hi Michael Cheng,

Your tips are really helpful. I have some following questions related to optimization. Can you please go through those?1

(1) Which operand can be used to set the chief ray incident on a particular point on the image plane?


(2) Is there anyway to fix the variable limit of the lens to vary in that particular limit? Let's say, radius is variable and how this we can limit in a particular range?

Best and Regards,


Faheem Ahmad

Hello Faheem,

Thank you for reply! Both are good questions and please see my answers below.

(1) Probably the easiest way is to define the Field with Real Image Height. There is no way to know where the chief ray would land on image plane if the Field Type is not Real Image Height.

(2) Usually the first method to try is to increase the boundary opearnd's weighting in merit function. However, sometimes this may not work or requires too high weighting that even affect the optimization stability. In case increasing weight doesn't work, I would suggest you just set the limitation to be smaller or larger. For example, assuming you want the Radius to be smaller than 100 in merit function, however you find, after optimization, the resulted Radius is always slightly larger, like '100.1'. And it doesn't work if you set the Weight of the operand to even 100 either. In this case, I would just set the limitation to 99.9. If that doesn't work, try 99.8. 

Hope this works for you!

Michael

Thank you Michael for your helpful response, it is working.

Best,


Faheem

If you are designing a hand-held optics, in terms of tolerancing and manufacturing. it is recommended to select diameter-to-thickness ratio of 8:1

In ZOS we can define those constraints using MNDT and MXDT operands by giving an interval

6< Diameter to thicknes ratio of the lens <10

The  Z-factor (Karow factor) describes the ability of a lens which leads automatically centering itself between bell clamps during centering in the fabrication and testing processes.

The Karow factor (Z factor) is given by 

D1 and D2 are clear apertures of the lens. R1 and R2 are the radii of the lens surfaces.

In ZOS we can define those using the operands below;

You can have a look at the webpage for further details

https://www.photonics.com/Articles/Nuances_in_Optical_Design_for_Manufacturing/a64048

The  Z-factor (Karow factor) describes the ability of a lens which leads automatically centering itself between bell clamps) during centering in the fabrication and testing processes.

 

The Karow factor (Z factor) is given by 

D1 and D2 are clear apertures of the lens. R1 and R2 are the radii of the lens surfaces.

 

In ZOS we can define those using the operands below;

 

 

 

 

You can have a look at the webpage for durther details

https://www.photonics.com/Articles/Nuances_in_Optical_Design_for_Manufacturing/a64048

to mantain the lens ability to self-center between two bell chucks, Karow (Z-factor) is recommended to be greater than 0.56

Hello Everyone,

Optimization is sometimes extremely painstaking in complex designs. I want to share one of my experience;

Decreasing the F/# or field of an existing design can lead to ray failures during lens evaluation and optimization. Sometimes we can get warning from OS as; total internal reflection (TIR) or ray intercept failures (where rays physically miss a surface). The solution is to gradually step by step walk up to the desired aperture or field in small increments, and accordingly optimize the lens at each step.