The screen has cropped linear polarizers so all the white light will be blocked. The first one lets one direction light pass, but the second would only pass the light that was blocked. Unless the crystal layers sandwiched between them is induced with electrons to turn the polarization of the passed light, so it can pass the 2nd one. It can then turn R G and B independently and to varying degree, so you get shades of grey and colours. This is obviously unlinear as it is about turning the polarization based in a current.
So then you put a 3rd polarizer in front. If it is linear than you can align it with the 2nd polarizer and you pass the same light as the 2nd one did, so its still white (with a slight ND effect). Then you align it with the 1st pol filter and then you block all the light that was turned to pass the 2nd one and it is black.
Then you take a circular polarizer in this "linear Rectified" light. It is less predictable which effect you get. The cir-pol has a quarterwave on one side and a linear polarizer on the other side. if I hold it up with the quarterwave towards the screen, it turns the linear polarized light into circular polarized light, with 2 directions with a phase shift between the two. blue is passed more turned one way , and green and red another way. See C1 and C2 graphs. Blue vs Yellow/Orange is opposites. Orange is yellow with more red. yellow is Red + Green in the additive world. So it is basically opposite from blue, but with more red passed light, as spectrums of polarizers often show is true. So we do have some opposing effects here.
If you hold the quarterwave away from the screen, you get black and white, because how the linear polarizer on the cir-pol filter comes first and the passed light hits the quarterwave and becomes circular polarized instead.
I have both types of pol-filters here and I just tested with both. It is true that linear makes Black/white and the circular makes it blue/yellow when you face the part that is facing the camera towards the screen. If you face that part towards yourself, it acts like the linear polarizer