US 12,248,165 B2
Illumination device and image scanner
Taisuke Makita, Tokyo (JP); Hiroyuki Kawano, Tokyo (JP); and Shigeru Takushima, Tokyo (JP)
Assigned to MITSUBISHI ELECTRIC CORPORATION, Tokyo (JP)
Appl. No. 17/912,857
Filed by Mitsubishi Electric Corporation, Tokyo (JP)
PCT Filed Apr. 3, 2020, PCT No. PCT/JP2020/015302
§ 371(c)(1), (2) Date Sep. 20, 2022,
PCT Pub. No. WO2021/199422, PCT Pub. Date Oct. 7, 2021.
Prior Publication US 2023/0144125 A1, May 11, 2023
Int. Cl. F21V 8/00 (2006.01); H04N 1/028 (2006.01); H04N 1/04 (2006.01)
CPC G02B 6/0055 (2013.01) [H04N 1/02835 (2013.01); H04N 1/04 (2013.01)] 19 Claims
OG exemplary drawing
 
1. An illumination device comprising:
a plurality of light sources; and
a light guide member to propagate light entering inside while reflecting the light, wherein
the light guide member includes:
an incidence part that has an incidence surface to allow light emitted from the plurality of light sources to enter and to guide the entered light towards a center of the light guide member in a major axis direction thereof; and
a central part that has a scattering surface to emit the light guided from the incidence part towards an illumination target body,
the plurality of light sources include:
a first light source that has a light emission surface facing the incidence surface; and
a second light source that has a light emission surface facing the incidence surface and is arranged on the central part's side relative to the first light source, and in a same cross-sectional view, the incidence part has:
a first curved surface that reflects the light entering through the incidence surface towards the central part; and
a second curved surface that is arranged on the central part's side relative to the first curved surface and reflects the light entering through the incidence surface towards the central part,
wherein the second light source is arranged on a central side of the light guide member relative to an end point of the second curved surface on an end part's side of the light guide member in a cross section at a plane orthogonal to the incidence surface and parallel to the major axis direction, and
the first curved surface and the second curved surface are joined at a discontinuity point in the cross section, and the first curved surface and the second curved surface lack symmetry about the discontinuity point in the cross section.