HIGH END DIY triplet projection lens

[Hezz]

Guys,

Here is a picture of a computer optimized wide angle cooke triplet which should work with LCD of 17 inch wide screen format. It has 450 mm FL and 40 degrees total field of vision. I will post design information and the lens can be scaled down for use with 15 inch LCD and lower FL.

Hezz

[Hezz]

Guys,

Here is a zip file which is a microsoft word document that has the technical drawings and spacing information for this lens design. If anyone out there needs this file in another word processor format just ask and I can probably put it in any major format as long as the wordprocessor can insert EMF (enhanced meta files) format.

Hezz

[Hezz]

For those interested,

Here is a zip file of a solidworks e-drawing of the lens solid model. With this you can view the lens design in 3D. Here is what you have to do.

1) Go to Solidworks home web page and locate the free e-drawing download.

2) Download solidworks e-drawings onto your computer and install it.

3) Download and unzip the following file.

4) Load it into Solidworks e-drawings and enjoy.

With e-drawing you can manipulate the model in real 3D space but you can not edit it. You can however, mark up notes and questions on the model and perhaps save the screen as a jpeg.

Enjoy.

Hezz

[Hezz]

To anyone who has downloaded the drawing files there is something you need to be aware of. It has to do with the sign conventions for numbers that the optical design software uses.

On the first lens it shows the second surface of the lens as having something like -8xxx.xxx number. Do not construe this to be a negative surface. In fact this is a positive surface but because everything is referenced to the first surface in terms of direction it is a negative number. In other words it is a positive surface but pointing the other direction. That is why it has a negative number. Because the curvature is so small it may appear as a straight or negative surface on a drawing. Hence my need to warn you all.

Hezz

[sullivan18]

How is this different form the regular triplet?

[jcbklyny]

... what makes it "High-end"? I thought you were working on a multi lens design.





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www.diybuildergroup.com

[Hezz]

JCB,

What makes it high end is that it is optimized to the point where it can no longer be improved without making the system more complex by adding more elements or by adding aspheric surfaces. This lens if built to spec would outperform any four element system that you could put together without going through the same computer optimization. In years past it took engineers months doing hundreds of calculations to approach a design like this but a computer can do millions of calculations in only a second or two.

We can also do a computer optimization for a four element lens design also. In fact by modifing this design by making the final lens into a cemented doublet we can make a tessar lens with somewhat better performance.

What I am saying is that using trial and error by mixing four lenses together is realistically going to be very difficult because you don't have enough lens values or time to look at every combination. Granted you could build the lens with stock lenses but it would perform lower than an optimized one of simpler design.

So we have the option of building a non optimized lens out of stock components or of starting with an optimized design and perhaps trying to find stock lenses for a couple of the lenses and leave one lens variable open for a custom made lens. Trying to optimize the design that way.

If you have a way to communicate with me your lens configuration I will model it and we will see how good it is. Perhaps it can be optimized with only one custom lens or something.

Hezz

[sullivan18]

so how do i make and or get one of these lenses?

[Dwiel]

You wouldnt happen to be able to make a zoom lens would you?

[Hezz]

Perhaps in the future but it would be very expensive to have made. The number of elements jumps up to about 8 -12 lenses and some of them would be hard to make. If I am going to design a zoom lens it is going to be a variable compression anamorphic lens which will work like a zoom lens but only in the vertical or horizontal plane.

Now as to making the lens. At this point you have two choices. One is to take the plans to an optical design firm and have them custom grind the lenses for you. I imagine this would not be cheap. The other is to make the lenses yourself by hand and then have them coated somewhere with the AR coating. I was hoping that someone out there had better access and funds to try to have one made. In the future I may try and redesign the lens for use with plastic lenses that can be hand made more easily but there is no reason that the lenses could not be made by hand. It's just work intensive. I may try and come up with a method that is doable in the future. Stay tuned, who knows what the future will bring.


Hezz