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In Step 10, figure 2 (the figure from the patent) the ‘optional’ polarizing filter (2072) is not very optional. And you skipped it in your summary image.
It’s likely a three-wavelength, 1/4-wave retarder used to rotate linearly-polarized light to circularly-polarized light before it bounces off the LCOS. The reflected light goes through another 1/4 wave so it’s now 1/2 a wave from the input light. That is - it’s linearly polarized 90 degrees from the original light. That’s why the polarizing beam splitter cube is able to separate the input field (100% coverage) from the LCOS-reflected fields. They’re 90 deg. different polarization.
Also, that means the RGB emitters aren’t likely LED’s. They’d have to be laser diodes (or VCSEL’s) to have the narrow spectrum necessary for the 1/4 wave retarding film.