Display apparatus, moving body, and method for mounting display apparatus

1. A display apparatus to project a light flux including image information toward one eye, the apparatus comprising:

an image formation unit configured to emit the light flux; and

a projection unit including;

a projection region limiting unit to limit a width of the light flux emitted from the image formation unit, the projection region limiting unit having a reflective surface, the reflective surface having a concave configuration; and

a semi-transmissive reflective unit to reflect the light flux emitted from the projection region limiting unit,

a distance between the semi-transmissive reflective unit and an imaging plane of the light flux being not more than 250 mm.

2. The apparatus according to claim 1 , wherein the projection region limiting unit includes a reflecting unit and a limiting unit, the reflecting unit having the reflective surface, the limiting unit being provided at a rim of the reflecting unit absorbing a light incident on the rim.

3. The apparatus according to claim 1 , wherein the projection region limiting unit limits a width in a lateral direction of the light flux reflected by the semi-transmissive reflective unit and projected toward a human viewer to be not more than 70 mm at a position of a head of the human viewer when viewed by the human viewer.

4. The apparatus according to claim 1 , wherein the distance between the semi-transmissive reflective unit and the imaging plane of the light flux is shorter than a distance between the imaging plane of the light flux and an eye of a human viewer, the light flux being reflected by the semi-transmissive reflective unit and being projected toward the human viewer.

5. The apparatus according to claim 1 , wherein the distance between the semi-transmissive reflective unit and the imaging plane of the light flux is not more than 1/2 of a distance between the semi-transmissive reflective unit and an eye of a human viewer, the light flux being reflected by the semi-transmissive reflective unit and being projected toward the human viewer.

6. The apparatus according to claim 1 , wherein

the image formation unit includes a light flux modulator to produce the light flux including the image information by modulating a light, and

the projection region limiting unit is disposed between the light flux modulator and the semi-transmissive reflective unit on an optical path of the light flux, and a position of the light flux modulator and a position of the semi-transmissive reflective unit have an imaging relationship.

7. The apparatus according to claim 1 , wherein

the image formation unit includes a light flux modulator to produce the light flux including the image information by modulating a light; and

an optical axis of a light emitted from the light flux modulator is tilted with respect to a normal of a major surface of the light flux modulator.

8. The apparatus according to claim 7 , wherein an angle between the optical axis and the normal is not less than 3 degrees and not more than 20 degrees.

9. The apparatus according to claim 1 , wherein

the image formation unit includes

a light source including:

a light producing device to produce a light; and

a tapered light guide, the light produced by the light producing device being incident on the tapered light guide, and

a light flux modulator to produce the light flux including the image information by modulating a light emitted from the tapered light guide.

10. The apparatus according to claim 9 , wherein

the tapered light guide has an emission surface opposing the light flux modulator, and

the emission surface is tilted with respect to an optical axis of the tapered light guide.

11. The apparatus according to claim 1 , wherein the semi-transmissive reflective unit includes at least one of a metal thin film and a dielectric thin film.

12. The apparatus according to claim 1 , wherein the display apparatus is configure not to project the light flux on other eye of an observer having the one eye.

13. The apparatus according to claim 1 , wherein

the projection unit further includes a first light-concentrating element, a second light-concentrating element, and a reflective mirror,

on an optical path of the light flux, the first light-concentrating element is provided between the image formation unit and the reflective mirror, the projection region limiting unit is provided between the image formation unit and the first light-concentrating element, and the second light-concentrating element is provided between the image formation unit and the projection region limiting unit,

the first light-concentrating element has a first focal distance,

the second light-concentrating element has a second focal distance,

a distance between the projection region limiting unit and the first light-concentrating element is set to be the first focal distance, and

a distance between the projection region limiting unit and the second light-concentrating element is set to be the second focal distance.

14. The apparatus according to claim 13 , wherein

an intermediate image is formed at a position between the reflective mirror and the first light-concentrating element, and

a distance between the position. and the first light-concentrating element is the first focal distance.

15. A moving body, comprising:

a display apparatus to project a light flux including image information toward one eye; and

a vehicle body, the display apparatus being mounted in the vehicle body,

the display apparatus including:

an image formation unit to emit the light flux; and

a projection unit including:

a projection region limiting unit to limit a width of the light flux emitted from the image formation unit, the projection region limiting unit having a reflective surface, the reflective surface having a concave configuration; and

a semi-transmissive reflective unit to reflect the light flux emitted from the projection region limiting unit,

a distance between the semi-transmissive reflective unit and an imaging plane of the light flux being not more than 250 mm.

16. The body according to claim 15 , wherein the projection region limiting unit limits a width in a lateral direction of the light flux reflected by the semi-transmissive reflective unit and projected toward a human viewer to be not more than 70 mm at a position of a head of the human viewer when viewed by the human viewer.

17. The body according to claim 15 , wherein

the image formation unit includes a light, flux modulator to produce the light flux including the image information by modulating a light, and

the projection region limiting unit is disposed between the light flux modulator and the semi-transmissive reflective unit on an optical path of the light flux, and a position of the light flux modulator and a position of the semi-transmissive reflective unit have an imaging relationship.

18. The body according to claim 15 , wherein

the image formation unit includes a light flux modulator to produce the light flux including the image information by modulating a light; and

an optical axis of a light emitted from the light flux modulator is tilted with respect to a normal of a major surface of the light flux modulator.

19. A method comprising:

mounting a display apparatus to project a light flux including image information toward one eye with a distance between an imaging plane of the light flux emitted from the projection region limiting unit and a semi-transmissive reflective unit to reflect the light flux emitted from the projection region limiting unit being 250 mm, the display apparatus including an image formation unit and a projection unit, the image formation unit to emit the light flux, the projection unit including a projection region limiting unit to limit a width of the light flux emitted from the image formation unit, the projection region limiting unit having a reflective surface, the reflective surface having a concave configuration.