Illumination device, lens, set of diffusion element and lens, sensor device, and traveling body
An illumination device includes: a light source that emits parallel light or divergent light; a diffusion element that receives the light emitted from the light source and emits the light at a diffusion angle of 50° or more and 110° or less; and a lens group that has negative power, receives the light from the diffusion element by a first surface, and emits the light from a second surface at a light distribution angle of 140° or more.
1 . An illumination device comprising:
a light source emitting parallel light or divergent light;
a diffusion element receiving the light emitted from the light source and emitting the light at a diffusion angle of 50° or more and 110° or less; and
a lens group having negative power, having a first surface that receives the light emitted from the diffusion element and a second surface that emits the light at a light distribution angle of 140° or more,
wherein an emission angle θ 1 of the light from the diffusion element, an emission angle θ 2 of the light from the first surface of the lens group, and an emission angle θ 3 of the light from the second surface of the lens group satisfy a relational requirement θ 2 −θ 1 ≤θ 3 −θ 2 ,
wherein the illumination device exhibits a light-intensity distribution having a coefficient of variation (CV value) of 0.05 or less within a range of −70°≤θ 3 ≤70°, the CV value being defined as a ratio of a standard deviation of the light intensity to an average light intensity in the same range.
2 . The illumination device according to claim 1 , wherein the lens group includes a meniscus lens and has negative power.
3 . The illumination device according to claim 1 , wherein the diffusion element is a microlens array.
4 . The illumination device according to claim 1 , wherein the lens group is a single meniscus lens having negative power.
5 . The illumination device according to claim 1 , wherein the illumination device has a light radiation efficiency of 0.75 or more in ranges of θ 1 max =27° to 58° and θ 3 max =70° to 90°, where a maximum value of θ 1 is θ 1 max and a maximum value of θ 3 is θ 3 max .
6 . A lens provided in the illumination device according to claim 1 .
7 . A set of a diffusion element and a lens provided in the illumination device according to claim 1 .
8 . A sensor device comprising the illumination device according to claim 1 .
9 . A traveling body comprising the sensor device according to claim 8 .