Virtual image display apparatus
A virtual image display apparatus includes a display device (image forming unit), a first mirror member configured to reflect imaging light from the display device, a second mirror member configured to reflect imaging light reflected by the first mirror member, and a third mirror member of a transmissive type configured to reflect imaging light reflected by the second mirror member toward a position of an exit pupil. One of the first mirror member and the second mirror member is a refractive reflective optical member that includes a refractive member including a refractive surface, and a mirror surface formed at a non-refractive surface of the refractive member.
1. A virtual image display apparatus comprising:
an image forming unit;
a first mirror member that reflects an imaging light from the image forming unit;
a second mirror member that reflects the imaging light reflected by the first mirror member; and
a third mirror member of a transmissive type that reflects the imaging light reflected by the second mirror member toward a position of an exit pupil, wherein
the second mirror member is a refractive reflective optical member that includes a refractive member including a refractive surface, an antireflective coating provided along the refractive surface, and a mirror surface formed at a non-refractive surface of the refractive member,
the refractive surface is a surface on which the imaging light reflected by the first mirror member is incident, and
the refractive surface emits the imaging light reflected by the mirror surface to the third mirror member.
2. The virtual image display apparatus according to claim 1 , wherein the refractive reflective optical member includes, as the refractive surface, an incidence surface and an emission surface provided independently of each other to transmit imaging light before and after reflection by the mirror surface.
3. The virtual image display apparatus according to claim 1 , wherein a reflecting surface or a mirror surface of the first mirror member, the second mirror member, and the third mirror member is an aspheric surface or a free curved surface.
4. The virtual image display apparatus according to claim 1 , wherein a refractive surface of the refractive reflective optical member is an aspheric surface or a free curved surface.
5. The virtual image display apparatus according to claim 4 , wherein the refractive surface is substantially perpendicular to a principal ray from the center of a screen.
6. The virtual image display apparatus according to claim 1 , wherein
the first mirror member and the third mirror member each are a mirror plate having a structure in which a mirror film is formed at one surface of a plate-like body.
7. The virtual image display apparatus according to claim 1 , further comprising a fourth mirror member on an optical path between the first mirror member and the image forming unit or between the first mirror member and the second mirror member.
8. The virtual image display apparatus according to claim 1 , wherein the image forming unit displays a distorted modification image for correcting a distortion aberration by the first mirror member, the second mirror member, and the third mirror member.
9. The virtual image display apparatus according to claim 1 , wherein the third mirror member covers a position of the exit pupil and has a shape concaved toward the exit pupil.
10. The virtual image display apparatus according to claim 1 , wherein an optical axis passing through the first mirror member, the second mirror member, and the third mirror member is arranged along a plane extending in a substantially vertical direction intersecting a lateral direction in which a pair of pupils of an observer are aligned.
11. The virtual image display apparatus according to claim 10 , wherein the first mirror member and the second mirror member are disposed on an upper side of the third mirror member to correspond to a head side of an observer.
12. The virtual image display apparatus according to claim 1 , wherein the refractive member of the refractive reflective optical member includes a material having an Abbe number greater than or equal to 50.
13. The virtual image display apparatus according to claim 1 , wherein a distance between the second mirror member and a position of the exit pupil is greater than or equal to 14 mm.