Image reading device

An image reading device comprising:

• a plurality of light-receiving pixels arranged in a predetermined arrangement direction and configured to receive light reflected on an imaging object, the imaging object being placed on a predetermined reference surface;
• a first light-shielding member including a plurality of first openings and disposed between the plurality of light-receiving pixels and the reference surface;
• a second light-shielding member including a plurality of second openings and disposed between the plurality of first openings and the reference surface;
• a third light-shielding member disposed between the second light-shielding member and the plurality of condenser lenses;
• a plurality of condenser lenses disposed between the plurality of second openings and the reference surface and disposed at a distance from the plurality of second openings;
• a first light-transmissive member disposed between the first light-shielding member and the second light-shielding member;
• and
• a second light-transmissive member disposed between the second light-shielding member and the plurality of condenser lenses, wherein
• the plurality of first openings are arranged to correspond to the plurality of light-receiving pixels respectively,
• the plurality of second openings are arranged to correspond to the plurality of light-receiving pixels respectively,
• the plurality of condenser lenses are arranged to correspond to the plurality of light-receiving pixels respectively,
• the plurality of third openings are arranged to correspond to the plurality of light-receiving pixels respectively,
• the plurality of condenser lenses, the second light-shielding member, the first light-shielding member, and the plurality of light-receiving pixels are arranged at positions at which the reflected light entering each light-receiving pixel of the plurality of light-receiving pixels sequentially passes through one of the plurality of condenser lenses corresponding to the each light-receiving pixel, one of the plurality of second openings corresponding to the each light-receiving pixel, and one of the plurality of first openings corresponding to the each light-receiving pixel and enters the each light-receiving pixel, and
• t2<MAX{M1,M2}
• where t0 denotes a distance between the plurality of light-receiving pixels, t1 denotes a thickness of the first light-transmissive member, t2 denotes a thickness of the second light-transmissive member, n denotes a refractive index of each of the first light-transmissive member and the second light-transmissive member, X0 denotes a width of ½ of a width of each of the plurality of light-receiving pixels in the arrangement direction, X1 denotes a width of ½ of an opening width of each of the plurality of first openings in the arrangement direction, X2 denotes a width of ½ of an opening width of each of the plurality of second openings in the arrangement direction, X3 denotes a width of ½ of an opening width of each of the plurality of third openings in the arrangement direction, and p denotes a distance between center positions of each two of the plurality of light-receiving pixels adjacent to each other in the arrangement direction,
• M1=(n·t0·(p−X3−X1)/(X0+X1))−t1, and
• M2=(n·t0+t1)·(p−X3−X2)/(X0+X2).