Line-of-sight direction control device

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.