COMPACT HEADS-UP DISPLAY

An optical system includes a reflective polarizer (20), and a display (10), first mirror (30a), and second mirror (30b) disposed on a same side of the reflective polarizer (20). The reflective polarizer (20) transmits an image emitted by the display (10) after the image is reflected by the first and second mirrors (30a, 30b). A mid-plane defined by intersection points between an optical axis of the system and the display (10), reflective polarizer (20), and second mirror (30b) has one-pass through four-pass regions having respective areas, A1 through A4. The one-pass region includes portions of the emitted image rays (15) that pass at least one time across the one-pass region, the two-pass region includes portions of the image rays (15) that pass at least two times across the two-pass region, the three-pass region includes portions of the image rays (15) that pass at least three times across the three-pass region, and the four-pass region includes portions of the image rays (15) that pass four times across the four-pass region, such that the ratio A4/A3 is between approximately 0.15 and approximately 0.40.