Image projection device
Provided is a technology for improving the resolution and the angle of view of an image projection device. The image projection device includes an optical waveguide element including at least one incident port on which a laser beam is incident and a plurality of emission ports from which the laser beam is emitted, and a scanning mirror that performs scanning with the laser beam emitted from the optical waveguide element, in which the laser beam with which the scanning mirror performs the scanning reaches a projection target. The image projection device further includes a hologram element that condenses the laser beam with which the scanning mirror performs the scanning on a vicinity of a pupil to allow the laser beam to reach a retina.
1. An image projection device, comprising:
an optical waveguide element including:
at least one incident port on which a laser beam is incident; and
a plurality of emission ports from which the laser beam is emitted;
a scanning mirror configured to perform scanning operation with the laser beam emitted from the optical waveguide element; and
a switching unit configured to switch at least one emission port, of the plurality of emission ports, from which the laser beam is emitted, wherein
the laser beam that reaches the switching unit is a combined laser beam in which a plurality of laser beams is combined,
a scanning line of the laser beam emitted from the at least one emission port of the plurality of emission ports is shifted from a scanning line of a laser beam emitted from another emission port, and
the laser beam with which the scanning mirror performs the scanning operation reaches a projection target.
2. The image projection device according to claim 1 , wherein the switching unit includes at least one optical switch.
3. The image projection device according to claim 1 , wherein the switching unit includes at least one Mach-Zehnder type optical switch.
4. The image projection device according to claim 1 , wherein an arrangement of the plurality of emission ports is such that a scanning line of a laser beam emitted from a first emission port of the plurality of emission ports is between facing parts of a scanning line of a laser beam emitted from a second emission port of the plurality of emission ports.
5. The image projection device according to claim 4 , wherein the second emission port and the first emission port are such that a line connecting the second emission port and the first emission port is perpendicular to a scanning direction of the scanning mirror.
6. The image projection device according to claim 1 , wherein an arrangement of the plurality of emission ports is such that a scanning range of a laser beam emitted from a first emission port of the plurality of emission ports is shifted from a scanning range of a laser beam emitted from a second emission port of the plurality of emission ports.
7. The image projection device according to claim 1 , wherein the at least one emission port from which the laser beam is emitted is switched for every specific number of frames.
8. The image projection device according to claim 1 , wherein a collimator lens that collimates the emitted laser beam is on an optical path between the optical waveguide element and the scanning mirror.
9. The image projection device according to claim 1 , further comprising a hologram element configured to condense the laser beam with which the scanning mirror performs the scanning operation, on a vicinity of a pupil to allow the laser beam to reach a retina.
10. The image projection device according to claim 1 , wherein the laser beam with which the scanning mirror performs the scanning operation reaches a projection surface without or through a projection optical system.