Lens design query

[tommurphy73]

Hello,

We currently use the cay033 aspheric lens from Philips for an application. This lens works reasonably well with some limitations.

In our application we are trying to holding 20 plastic optic fibers in a 5X4 grid arrangement. The image from these fibers is focused using the cay033 onto a cmos image sensor (as used in digital cameras) with an amplification of 0.5.

We have found that the image will only be focused at the centre but be blurred at the edges. Is there any way to get an image which has a good focus throughout the image

Any help or recommendations would be appreciated.

Regards
Tom Murphy

 

[IRstuff]

yes, make a smaller image. or chose a better lens


Your chosen optic is a lens for LASER DIODES, which are POINT SOURCES. Why would you expect this lens to image an extended source?

TTFN

 

[tommurphy73]

Hi,

Thanks for the response.

Could you recommend a lens for use with an extended source and still have a short focal length to keep the overall size to a minimum.

Regards
Tom

 

[cev]

Your biggest problem is that the CAY033 is designed for infinite conjugates (collimation), but you are using it for 1:2 conjugate imaging. High-NA lenses perform terribly when used away from their design specifications.

For your application, you may use two aspheric optics back-to-back. One focal length is ~1/2 of the other, so that light is collimated between the two optics.

As per IRstuff's comments, you must verify that the performance of the lenses is acceptable for your maximum object and image heights. The off-axis performance of the CAY033 is plotted on the Thorlabs web site. Units are not included, but I interpret "field radius" in millimeters and "RMS" as spot size in microns.

CV