How to set a variable to a string with special characters?

I want to set a variable to

<cfset inputstring = "<img src="../../../server/win/form/stamp/string_1" />"/>

but i keep getting error:

 Invalid CFML construct found on line 184 at column 32.
ColdFusion was looking at the following text:


.

I have try it different ways , what i'm i doing wrong?