Hi Dayong,
First of all light framework page is based on HTMLB that does not support standards mode, so it is not recommended to use it with IE=Edge.
2nd, since it is HTMLB based and HTMLB is only quirks mode HTMLB always add the x-ua-compatible header with EmulateIE7.
To fix the 2nd point SAP Note:
2255492 - X-UA-Compatible response header is set twice in classic framework page
It's also relevant for light framework page, by applying this note you will be able to use the browser document mode iView and whatever you set it on will reflect.
BR,
Saar