Line-of-sight direction control device

Patent metadata

Field	Value
Publication number	US-10481381-B2
Application number	US-201414902996-A
Country	US
Kind code	B2
Filing date	Jun 25, 2014
Priority date	Jul 5, 2013
Publication date	Nov 19, 2019
Grant date	Nov 19, 2019

Abstract

An object of the present invention is to widen a range in which line of sight change is possible, particularly in a pan direction. According to the present invention it is possible to acquire high line of sight changing speed. A pan mirror is capable of rotation in forward and reverse directions about a third rotational axis. Also, the third rotational axis extends in a direction that is substantially parallel to a line of sight direction directed from a tilt direction control section to the pan mirror. An angle α formed by the pan mirror and the third rotational axis is set in a range 0°<α<90°. The tilt direction control section can scan line of sight direction with respect to a virtual plane formed by a rotation locus of the pan mirror. The tilt direction control section can also control tilt angle of the line of sight direction from the pan mirror to a physical object. The pan mirror can control pan angle of the line of sight direction from the pan mirror to the physical object by being rotated about the third rotational axis.

First claim

The invention claimed is:

1. A line of sight direction control device for controlling line of sight direction to be directed from an optical device toward a physical object, comprising:
a tilt direction control section and a pan direction control section,
the tilt direction control section comprising a first tilt mirror and a second tilt mirror, wherein:
the first tilt mirror is rotatable by a drive mechanism in forward and reverse directions about a first rotational axis,
the second tilt mirror is rotatable by a drive mechanism in forward and reverse directions about a second rotational axis, and
the second rotational axis extends in a direction that is perpendicular to the first rotational axis,

the pan direction control section comprising a pan mirror having a rotational axis member disposed on a backside of the pan mirror, wherein:
the pan mirror is rotatable by a drive mechanism coupled to the rotational axis member, in forward and reverse directions about a third rotational axis, and
the rotational axis member extends from the backside of the pan mirror along the third rotational axis in a direction that is parallel to a line of sight direction running from the second tilt mirror of the tilt direction control section toward the pan mirror, and

wherein:
the pan mirror is installed in a direction that is inclined with respect to the rotational axis member,
the tilt direction control section scans a line of sight direction with respect to a virtual surface formed by a rotational locus of a front side of the pan mirror, by rotating the first tilt mirror and the second tilt mirror,
the tilt direction control section controls a tilt angle of the line of sight direction from the front side of the pan mirror to a physical object by rotating the first tilt mirror and the second tilt mirror,
the pan direction control section controls a pan angle of the line of sight direction from the front side of the pan mirror to the physical object, by rotating the pan mirror about the rotational axis member, and
the line of sight direction control device further comprises a pupil shift optical system, and the pupil shift optical system transfers a pupil position of line of sight to the vicinity of any one of the first tilt mirror, the second tilt mirror, and the pan mirror.

2. The line of sight direction control device of claim 1 , wherein the first rotational axis extends in a direction that is perpendicular to a normal vector of the first tilt mirror, and
the second rotational axis extends in a direction that is perpendicular to a normal vector of the second tilt mirror.

3. The line of sight direction control device of claim 1 , wherein a position of the first rotational axis is coincident with a center of a beam of light that is incident on the first tilt mirror, and
a position of the second rotational axis is coincident with a center of a beam of light that is irradiated to the second tilt mirror.

4. The line of sight direction control device of claim 1 , wherein a center of a region in which line of sight direction can be scanned by the tilt direction control section is coincident with a position of the third-rotational axis member.

5. A design method for a line of sight direction control device, provided with a tilt direction control section and pan direction control section, wherein:
the tilt direction control section comprises a first tilt mirror and a second tilt mirror,
the first tilt mirror is rotatable by a drive mechanism in forward and reverse directions about a first rotational axis,
the second tilt mirror is rotatable by a drive mechanism in forward and reverse directions about a second rotational axis,
the second rotational axis extends in a direction that is perpendicular to the first rotational axis,
the pan direction control section comprises a pan mirror having a rotational axis member disposed on a back side of the pan mirror,
the pan mirror is rotatable by a drive mechanism coupled to the rotational axis member, in forward and reverse directions about a third rotational axis, and
the rotational axis member extends from the backside of the pan mirror along the third rotational axis in a direction that is substantially parallel to a line of sight direction running from the second tilt mirror of the tilt direction control section toward the pan mirror, and wherein:
the pan mirror is installed in a direction that is inclined with respect to the rotational axis member,
an angle α formed by the pan mirror and the rotational axis member is set in a range of 0°<α<90°,
the tilt direction control section scans a line of sight direction with respect to a virtual surface formed by a rotational locus of a front side of the pan mirror, by rotating the first tilt mirror and the second tilt mirror,
the tilt direction control section controls a tilt angle of the line of sight direction from the front side of the pan mirror to a physical object by rotating the first tilt mirror and the second tilt mirror,
the pan mirror controls a pan angle of the line of sight direction from the front side of the pan mirror to the physical object, by rotating about the rotational axis member, and
the line of sight direction control device further comprises a pupil shift optical system, and the pupil shift optical system transfers a pupil position of line of sight to the vicinity of any one of the first tilt mirror, the second tilt mirror, and the pan mirror,
the design method further comprising,
(a) a step of calculating shapes of the first tilt mirror, the second tilt mirror, and the pan mirror using ray tracing, so that line of sight directions subjected to direction conversion by the first tilt mirror, the second tilt mirror, and the pan mirror satisfy given required specifications; and
(b) a step of searching for design parameters for the first tilt mirror, the second tilt mirror, and the pan mirror by optimizing evaluation functions of the first tilt mirror, the second tilt mirror, and the pan mirror, with the search for deign parameters being carried out with the fact that collision does not occur between the first tilt mirror, the second tilt mirror, and the pan mirror as a constraint condition.

6. The design method of claim 5 , wherein a constraint condition is further that after line of sight that was directed towards the pan mirror from the tilt direction control section has been reflected at the pan mirror, the line of sight does not strike the first tilt mirror or the second tilt mirror.

7. The design method of claim 5 , wherein the evaluation functions used in previously described step (b) are for acquiring maximum value of minimum acceleration achievable for the first tilt mirror, the second tilt mirror and the pan mirror.

8. A non-transitory computer readable medium having computer-executable instructions stored thereon, wherein in response to execution of the instructions by a computer, the computer performs each of the steps of the design method for the line of sight direction control device of claim 5 .

9. The line of sight direction control device of claim 1 , wherein a range in which the pan mirror can rotate is set substantially 360° about the rotational axis member on the backside of the pan mirror.

Assignees

• Univ Tokyo

Inventors

• Oku Hiromasa
• Ishikawa Masatoshi
• Kobayashi Koseki

Classifications

• H04N23/60

  Control of cameras or camera modules · CPC title

• H04N23/58

  Means for changing the camera field of view without moving the camera body, e.g. nutating or panning of optics or image sensors · CPC title

• H04N23/00

  Cameras or camera modules comprising electronic image sensors; Control thereof · CPC title

• G03B17/56

  Accessories (carrying-cases A45C11/38) · CPC title

• G02B23/14 Primary

  Viewfinders (for photographic apparatus G03B13/02) · CPC title