Intensities from the Michelson Beamsplitter

[Identity]

(A laser monochromatic laser is shone in from the left, that's E_{in}.)

http://img820.imageshack.us/img820/6184/beamsplitter.png

In the lecture notes, it says that:

E_{out1}=rE_2+tE_1, where E_1=-rE_{in}e^{i\phi} and E_2=tE_{in}e^{i\phi}

I don't really understand the signs (+/-) here.

According to the Fresnel equations, light reflecting off a material with a higher refractive index will experience a 180 degree phase shift, hence the minus sign in the E_1 equation. But then why isn't there also a minus sign here: E_{out1}=(-)rE_2+tE_1, is E_2 not also reflecting off a material with higher refractive index?

Thanks