Imaging apparatus, detecting apparatus, and imaging method
As light is allowed to impinge from above a microplate M and an imaging unit 13 (a line sensor 131 and an imaging optical system 132 ), which moves in a scanning motion along the bottom surface of the microplate M, receives transmitted light, images of wells W formed in the microplate M are captured. The scope of imaging by the line sensor 131 is greater than the diameter of at least one well W, or preferably, encompasses a plurality of wells. When the depth of field of the optical system 132 is 0.6 mm or less, the influence of reflection of side walls of the wells upon the images is reduced.
1. An imaging apparatus for imaging a sample plate whose surface has a plurality of wells which are capable of holding a fluid, comprising:
an illumination member which irradiates light from above the sample plate which is in a horizontal condition; and
an imager member which receives transmitted light which is transmitted to below the sample plate and captures an image which includes at least one of the wells,
wherein the imager member includes an imaging element and an optical system which focuses the transmitted light upon the imaging element, and a depth of field of the optical system is equal or smaller than 0.6 mm;
wherein the depth of field is defined by a following formula:
Dof =2 sf 2 δF ( f+s )/{ f 4 −δ 2 F 2 ( f+s ) 2 }
where a symbol Dof denotes the depth of field, a symbol s denotes a distance between a principal point of the optical system and a bottom surface of the well, a symbol f denotes a focal length of the optical system as measured on the imaging element side, a symbol F denotes a F-number of the optical system, and a symbol δ denotes a pixel pitch of the imaging element.
2. The imaging apparatus of claim 1 , wherein the imaging element is a line sensor, and the imager member comprises a mover mechanism which moves the optical system and the line sensor together as one unit relative to the sample plate along a bottom surface of the sample plate.
3. The imaging apparatus of claim 1 , wherein an image plane at which an image corresponding to the bottom surface of the well is imaged by the optical system coincides with a light receiving surface of the imaging element.
4. The imaging apparatus of claim 1 , wherein the imager member captures an image which contains the plurality of wells.
5. The imaging apparatus of claim 1 , wherein the illumination member irradiates white light upon the sample plate.
6. A detecting apparatus, comprising:
an imager part which has a same structure as that of the imaging apparatus of claim 1 ; and
a detector part which detects a specific section, which is contained in a liquid-state or solid-state culture medium which is held in the well and which exhibits a different optical characteristic from a culture medium, based upon an image captured by the imager part.
7. An imaging method of imaging a sample plate which has a plurality of wells which hold a liquid-state or solid-state culture medium, comprising the steps of:
irradiating light from above the sample plate which is in a horizontal condition; and
capturing an image containing at least one of the wells by an imaging element while the optical system focuses a light transmitted to below the sample plate upon the imaging element, wherein
a depth of field of the optical system is equal to or smaller than 0.6 mm,
wherein the depth of field is defined by a following formula:
Dof =2 sf 2 δF ( f+s )/{ f 4 −δ 2 F 2 ( f+s ) 2 }
where a symbol Dof denotes the depth of field, a symbol s denotes a distance between a principal point of the optical system and a bottom surface of the well, a symbol f denotes a focal length of the optical system as measured on the imaging element side, a symbol F denotes a F-number of the optical system, and a symbol δ denotes a pixel pitch of the imaging element.
8. The imaging method of claim 7 , wherein an image plane at which an image corresponding to the bottom surface of the well is imaged by the optical system coincides with a light receiving surface of the imaging element.