US 11,921,030 B2
Gas detection apparatus
Takaaki Furuya, Tokyo (JP); and Keiichiro Kuwata, Tokyo (JP)
Filed by Asahi Kasei Microdevices Corporation, Tokyo (JP)
Filed on Oct. 28, 2021, as Appl. No. 17/452,617.
Claims priority of application No. 2020-180845 (JP), filed on Oct. 28, 2020; and application No. 2021-122620 (JP), filed on Jul. 27, 2021.
Prior Publication US 2022/0128449 A1, Apr. 28, 2022
Int. Cl. G01N 21/03 (2006.01); G01N 21/3504 (2014.01); G01N 21/61 (2006.01)
CPC G01N 21/031 (2013.01) [G01N 21/3504 (2013.01); G01N 21/61 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A gas detection apparatus comprising:
a light emitting part;
a light receiving part; and
a light guiding part for guiding light from the light emitting part to the light receiving part, wherein
a shape of at least a part of an inner surface of the light guiding part is composed of all or a part of n (n: one or more natural numbers) ellipsoids, and when:
then ellipsoids are defined as ellipsoids E1, E2, . . . , E(n-1) and En;
an ellipse having a maximum area in a cross-section of an ellipsoid Ei (i: a natural number satisfying 1≤i≤n) is defined as an ellipse Eci;
an ellipsoid that passes through two focal points Fai and Fbi of the ellipse Eci and has a minimum volume having a scaling relationship with the ellipsoid Ei without being rotated is defined as an ellipsoid Esi;
a region inside the ellipsoid Ei and not including the ellipsoid Esi is defined as a region Ri;
the ellipsoid Ei including a light source region of the light emitting part is defined as an ellipsoid Es;
the ellipsoid Ei including a light receiving region of the light receiving part is defined as an ellipsoid Ed;
the region Ri of the ellipsoid Es is defined as a region Rin; and
the region Ri of the ellipsoid Ed is defined as a region Rout;
60% or more of the light source region is present in the region Rin and 60% or more of the light receiving region is present in the region Rout,
wherein the inner surface of the light guiding part is reflective; wherein, when a maximum length of the light source region is defined as Ls and a maximum length of the ellipsoid Es is defined as Lms, Ls≥Lms/50; and wherein, when a maximum length of the light receiving part is defined as Ld and a maximum length of the ellipsoid Ed is defined as Lmd, Ld≥Lmd/50.