Virtual image display device and optical unit capable of adjusting display position of virtual image
A virtual image display device includes a first display device for a right eye, a second display device for a left eye, a lens barrel or the like serving as an assembly member configured to assemble the first display device and the second display device, and first and second correction units serving as post-assembly adjustment devices configured to adjust a display state of the first display device and the second display device assembled by the assembly member.
1. A virtual image display device comprising:
a first display device that includes a first display element emitting a first imaging light, a first light-guiding system guiding the first imaging light, and a first projection optical system emitting the first imaging light from the first display element to the first light-guiding system, wherein the first display element and the first projection optical system align along a first optical axis of the first projection optical system;
a second display device that includes a second display element emitting a second imaging light, a second light-guiding system guiding the second imaging light, and a second projection optical system emitting the second imaging light from the second display element to the second light-guiding system, wherein the second display element and the second projection optical system align along a second optical axis of the second projection optical system;
a first assembly member that is assembled to the first display device, wherein the first assembly member adjusts a relative position between the first display element and the first projection optical system along the first optical axis;
a second assembly member that is assembled to the second display device, wherein the second assembly member adjusts a relative position between the second display element and the second projection optical system along the second optical axis; and
a post-assembly adjustment device that adjusts a position of a display area in each of the first display element and the second display element based on a difference between a first incident angle of the first imaging light emitted by the first light-guiding system with respect to a position of a first exit pupil and a second incident angle of the second imaging light emitted by the second light-guiding system with respect to a position of a second exit pupil, wherein
the first assembly member comprises a first case member that houses the first display element and a first lens barrel that houses the first projection optical system, and the first case member is configured to move relative to and attach to the first lens barrel,
the first lens barrel comprises a first excavated portion,
the first case member comprises a first protruding portion configured to insert to the first excavated portion,
a first gap is formed between the first excavated portion and the first protruding portion when the first protruding portion is inserted to the first excavated portion,
the second assembly member comprises a second case member that houses the second display element and a second lens barrel that houses the second projection optical system, and the second case member is configured to move relative to and attach to the second lens barrel,
the second lens barrel comprises a second excavated portion,
the second case member comprises a second protruding portion configured to insert to the second excavated portion, and
a second gap is formed between the second excavated portion and the second protruding portion when the second protruding portion is inserted to the second excavated portion.
2. The virtual image display device according to claim 1 , wherein
in a first direction in which the first display device and the second display device align, the first assembly member adjusts postures of the first display device with relative to postures of the second display device adjusted by the second assembly member.
3. The virtual image display device according to claim 2 , wherein
an adjustment amount of assembly using the first assembly member is greater than an adjustment amount of the post-assembly adjustment device.
4. The virtual image display device according to claim 1 , wherein
the first assembly member adjusts a first relative positions between the first display element and the first light-guiding system, and
the second assembly member adjusts a second relative positions between the second display element and the second light-guiding system.
5. The virtual image display device according to claim 4 , wherein
the display area of the first display element is narrower than a display effective area of the first display element,
the first display element includes a margin region such that the display area is variable in the display effective area, and
the post-assembly adjustment device includes an image processing circuit that converts an input image signal to a first image signal and that outputs the first image signal to the first display element.
6. The virtual image display device according to claim 5 , wherein
the image processing circuit is an enlargement processing circuit that converts the input image signal to the first image signal that is greater a number of pixels than a number of the input image signal.
7. The virtual image display device according to claim 6 , wherein
the post-assembly adjustment device performs one of parallel displacement of a display position and rotation of the display position within a range of the number of pixels of the first image signal increased due to conversion by the enlargement processing circuit.
8. The virtual image display device according to claim 5 , wherein
the image processing circuit is a reduction processing circuit that converts the input image signal to a second image signal that is smaller a number of pixels than a number of pixels of the display effective area in the first display element.
9. The virtual image display device according to claim 8 , wherein
the post-assembly adjustment device performs one of parallel displacement of a display position and rotation of the display position within a range of a difference between the number of pixels of the first image signal decreased due to conversion by the reduction processing circuit and the number of pixels of the display effective area in the first display element.
10. The virtual image display device according to claim 5 , wherein
the post-assembly adjustment device performs conversion processing on the first image signal branched into two, corresponding to the first display device and the second display device, and the conversion processing differs between the two branched signals.
11. The virtual image display device according to claim 5 , wherein
the image processing circuit includes a distortion correction circuit configured to perform distortion correction canceling out distortion generated by the first light-guiding system and
the distortion correction circuit makes corrections to differing extents according to a wavelength region of the first imaging light exiting the first display element.
12. The virtual image display device according to claim 4 , wherein
the first light-guiding system includes:
a projection optical system that converges the first imaging light from the first display element;
a prism that includes an incident surface in which the first imaging light is incident, an exit surface that emits the first imaging light, and a reflection surface that reflects the first imaging light from the incident surface toward the exit surface; and
a mirror that reflects a part of the first imaging light from the prism toward a pupil position and that transmits another part of the first imaging light.
13. The virtual image display device according to claim 12 , wherein
a Z-shaped optical path is formed by two-stage folding obtained by folding an optical path at the reflection surface of the prism and folding the optical path at the mirror.
14. The virtual image display device according to claim 12 , wherein
the first light-guiding system forms an off-axis optical system.
15. The virtual image display device according to claim 1 , wherein
as a position adjustment for a virtual image to be visually recognized, the post-assembly adjustment device makes an adjustment in a second direction that intersects with a first direction in which the first display device and the second display device align.
16. An optical unit comprising:
a first display device that includes a first display element emitting a first imaging light, a first light-guiding system guiding the first imaging light, and a first projection optical system emitting the first imaging light from the first display element to the first light-guiding system, wherein the first display element and the first projection optical system align along a first optical axis of the first projection optical system;
a second display device that includes a second display element emitting a second imaging light, a second light-guiding system guiding the second imaging light, and a second projection optical system emitting the second imaging light from the second display element to the second light-guiding system, wherein the second display element and the second projection optical system align along a second optical axis of the second projection optical system;
a first assembly member that assembles the first display device, wherein the first assembly member adjusts a relative position between the first display element and the first projection optical system along the first optical axis;
a second assembly member that assembles the second display device, wherein the second assembly member adjusts a relative position between the second display element and the second projection optical system along the second optical axis; and
a post-assembly adjustment device that adjusts a position of a display area in each of the first display device and the second display device based on a difference between a first incident angle of the first imaging light emitted by the first light-guiding system with respect to a position of a first exit pupil and a second incident angle of the second imaging light emitted by the second light-guiding system with respect to a position of a second exit pupil, wherein
the first assembly member comprises a first case member that houses the first display element and a first lens barrel that houses the first projection optical system, and the first case member is configured to move relative to and attach to the first lens barrel,
the first lens barrel comprises a first excavated portion,
the first case member comprises a first protruding portion configured to insert to the first excavated portion,
a first gap is formed between the first excavated portion and the first protruding portion when the first protruding portion is inserted to the first excavated portion,
the second assembly member comprises a second case member that houses the second display element and a second lens barrel that houses the second projection optical system, and the second case member is configured to move relative to and attach to the second lens barrel,
the second lens barrel comprises a second excavated portion,
the second case member comprises a second protruding portion configured to insert to the second excavated portion, and
a second gap is formed between the second excavated portion and the second protruding portion when the second protruding portion is inserted to the second excavated portion.