US Patent 10302957 Polarizing beam splitter with low light leakage

In some embodiments, a polarizing beam splitter is provided. The beam splitter may comprise an optically transmissive spacer having first and second opposing faces, with a first polarizer on the first opposing face and a second polarizer on the second opposing face. The optically transmissive spacer may separate first and second triangular prisms of a cube-type beam splitter, with the first polarizer between the first triangular prism and the first opposing face of the spacer, and the second polarizer between the second triangular prism and the second opposing face of the spacer.