who can supply standard Fresnel lens?

who can provide standard Fresnel lens? I have to buy from www.fresneltech.com/ which is very expensive. you can find their catalog at http://www.fresneltech.com/pdf/FresnelLenses.pdf

please send me your catalog to fwang@asmpt.com. you can find we are a worthy customer.

Please don't ask me for the mass production, what we need is small amount but versatility.

我知道山东有一家在给3M配套做书写投影仪上的fresnel透镜，实力应该不错。

这是一个什么样的产品啊？有什么作用？

成像

了解的人越來越多,應用也越來越廣,但是光損失的部份不知道有沒有人能解決?