OPTICAL SYSTEM, VIRTUAL IMAGE DISPLAY DEVICE, AND HEAD-MOUNTED DISPLAY

An optical system includes a light guide, a partial reflector, and a polarizer. The light guide has a light-emission surface; and an outer surface opposite to the light-emission surface. The polarizer is on the outer surface to transmit a part of incident light incident on the polarizer. The polarizer has a first transmittance in a first polarization direction higher than a second transmittance in a second polarization direction orthogonal to the first polarization direction, with respect to vertical incident light incident perpendicularly on the polarizer. The partial reflector has a first reflectance in the first polarization direction lower than a second reflectance in the second polarization direction, with respect to the vertical incident light.