Front surface cyl - SF blanks

**Jamie Brady** · 01-25-2007, 09:39 AM

Does anyone know of any lens manufacturer that currently manufacturers a semi-finished blank with front surface cylinder?

Yes, I realize that front surface cyl was the way it used to come "back in the day", however, this is a for real question as I need to create a lens with front surface cylinder. My generator cannot generate on the + surface and I don't want to farm the job out.

CR-39 is my material of choice, however any will do.

Thanks for your collective knowledge.

**Jacqui** · 01-25-2007, 12:28 PM

Augen makes some in Trivex

**Audiyoda** · 01-25-2007, 12:36 PM

Resolution Poly has a Atoric front surface.

The Augen lens is atoric as well - curves are equaled from and back.

**Jamie Brady** · 01-25-2007, 12:49 PM

Nope, not what I'm looking for. Not looking for an aspheric or atoric front surface, but a front surface with with a toric curve in one meridian.

Thanks for the input, just not what I'm looking for.

**Audiyoda** · 01-25-2007, 12:55 PM

Jamie - I called my lab. There's nothing on the market like you are describing. He said they could do it - depending on the back curve you'd need they can generally give you about a 3 or 4 diopter curve over the back curve.

**Fezz** · 01-25-2007, 01:01 PM

Try fellow Optiboarder=Awtech. His company can do just about anything. I imagine this would be a piece of cake.

**CME4SPECS** · 01-25-2007, 01:53 PM

I understand what you want. But why?

**Jamie Brady** · 01-25-2007, 02:17 PM

I need to make a meridianal magnifying lens. One which has no refracting power but, magnifies in only one meridian. The lens has value for research in the condition of aniseikonia as well as a teaching device to demonstrate just what aniseikonic patients actually see to optometry students. If the lens was cut and edged into a round frame it could then be marked with the meridian of magnification and twisted with the rule, against the rule and oblique so one could wear the frame and "see" how this condition affects the vision of someone with this condition. I will make lenses in 1%,2%,4%,6% magnification. At roughly 6% a patient will begin to suppress vision and become monocular. Simply put -- a teaching tool.

I realize that I can order from a lab that can surface the front surface of a lens. I just wanted to do it myself and save the $$.

**FVCCHRIS** · 01-25-2007, 03:10 PM

Jamie, I'd love to know who you get to surface that + cyl. The demonstration sounds interesting. Are you going to mount it(them) in a trial frame? Chris..

**allanon** · 01-25-2007, 03:27 PM

I recently had a non-adapt ... come to find out, his old glasses (2002) were front cylinder.

**Chris Ryser** · 01-25-2007, 03:28 PM

You can find that finished and in stock at Edmund Optics:

TECH SPEC™ High Performance Cylinder Lenses

[ Specification Table | Related Products | Helpful Literature | Product Matrix | Technical Images ] Focuses light in only one dimension. Similar to a PCX lens in profile, but is a portion of a cylinder instead of a sphere. Cylinder lenses can transform a point of light into a line image. This is useful for making laser line generators. The lens magnifies in one dimension so it can be used for stretching images. Can be used for focusing light into a slit or converging light for a line scan detector. Due to a tighter tolerance on tilt and wedge, high performance imaging lenses will give straighter lines and better images than our standard cylinder lenses. All dimensions are in mm. :D

website at: http://www.edmundoptics.com/onlineca...productid=2053

**Jamie Brady** · 01-25-2007, 03:57 PM

Yes, I intend to mount these lenses into a frame. Thickness may prevent this in the higher magnification. The magnification will result from thickness not refractive power.

Chris, thanks for the Edmund info, however, none of their lenses will work as they all have too much magnification (or too short of a focal length). Great info none the less. I've ordered the Edmund catalog, cool stuff.

Old Coburn 113 generators could generate front surface curves and I'm sure many others. There are labs currently that can do this work easily. As I mentioned earlier I was just hoping to do it myself and thought perhaps someone might know of a product that I didn't.

Thanks all,

Jamie

**DragonLensmanWV** · 01-26-2007, 03:23 PM

The Optronics generator we have can do a limited amount of front cyl,, sa up to 3D, depending on the base curve. I had to do a 4D cyl on some blended myodisks, but the generator would not cut it all and I had to hand-fine them.
I would bet any lab with a freeform generator could do that with their eyes closed.

RT · 01-26-2007, 04:57 PM

Any Gerber SG8/SGX generator can not only cut the front cyl, but can also cut a lap to match.

**Jacqui** · 01-26-2007, 05:10 PM

Originally Posted by RT

Any Gerber SG8/SGX generator can not only cut the front cyl, but can also cut a lap to match.

Ditto with the Optek, but freeform would be the way to go.

**gemstone** · 01-26-2007, 06:36 PM

Originally Posted by Jacqui

Ditto with the Optek, but freeform would be the way to go.

Have you ever tried that? Has anyone ever tried that? What is the higest convex curve you have successfully surfaced? What kind of surfacer? That aint no gimmi!

**Jacqui** · 01-26-2007, 08:40 PM

Originally Posted by gemstone

Have you ever tried that? Has anyone ever tried that? What is the higest convex curve you have successfully surfaced? What kind of surfacer? That aint no gimmi!

The highest curve I personally have done is about an 11.00. It's basically the same as doing a saddle back. It's an Optek SL generator and FB cylinder machines.

**HarryChiling** · 01-28-2007, 05:17 PM

Originally Posted by RT

Any Gerber SG8/SGX generator can not only cut the front cyl, but can also cut a lap to match.

if you have any directions on how I would be interested, becasue my SGX keeps giving me errors when I try to cut any front curves. I have mentioned it to some of the support people and the farthest I have gotten is it shouldn't do that. :(

**Audiyoda** · 01-29-2007, 09:48 AM

When I was in the lab working on a SGX we had to manually enter the curve information but it worked. I think the highest we could get was 5D and that was a limitation of the block that needed to be cut, not the lens.

**HarryChiling** · 01-29-2007, 09:59 AM

I tried manually entering it and it does not work. Thanks for the suggestion though.

**Lab Guy** · 07-12-2007, 10:26 AM

the SG-8 would do saddle backs but there was some limitation on the combinations of curves. You often need to change the axis by 90 degrees and transpose the curves,also just because the gen will cut the curve doesn't always mean your cylinder machines will run them. High plus curves and Accuity or 506 machines and abrasive fining pads don't mix well(the lenses tend to rock on the lap tables).