[OpenSPIM] The shape of light-sheet from a illumination objective

[胡衍]

Dear openSPIM list,

This is Yan, from China.
I built a light-sheet microscopy following the openSPIM,
but I found the light sheet shape changing from vertical to horizontal.

The optic path followed the openSPIM,
There was a vertical light sheet in front of the illumination objective.
This sheet focused in the position of working distance away from illumination objective,
the thinnest sheet in vertical direction.
But after this position the vertical direction height became smaller, 
and the horizontal direction width became larger. 
There is a position long away from the illumination position, 
the light sheet became thinnest in the horizontal direction.

Is there anyone knowing such thing? What is the problem?
I don't know the reason, so I don't know how to change the optic path.

I am looking forward for your reply.
Best regards,
Yan