FIG. 29 shows an incubator 9 conventionally used for culturing various microorganisms or cells. The incubator 9 comprises a chamber 91 having an opening 90 closable with a door 92 and a plurality of racks 93 arranged in the interior of the chamber, and is adapted to place a plurality of microplates 31 on the respective racks 93. The chamber 91 is provided with an environment adjusting device (not shown) for adjusting the ambient conditions inside the chamber 91, such as temperature, humidity, carbon dioxide concentration, etc. Samples on the microplates 31 are cultured under suitable ambient conditions set by the device.
To check the state of samples being cultured in the incubator 9, the microplate 31 is withdrawn from the chamber 91, and the samples are observed or analyzed using, for example, a microscope. Since the door 92 of the chamber 91 must be opened at such a time, there is the problem that the interior ambient conditions of the chamber 91 are greatly altered by opening the chamber.
Accordingly, an incubator has been proposed in which the microplate is made transportable between a microplate inlet formed in the chamber and a microplate accommodating portion within the chamber so that the microplate can be moved into or out of the accommodating portion automatically (see, for example, the publication of JP-A No. 1999-89559). Because the proposed incubator can be thus adapted by forming a small microplate inlet in the chamber, the internal ambient conditions of the chamber will not be altered greatly by moving the microplate into or out of the chamber.
Furthermore an incubator has been proposed which comprises a microscopic observation device having a camera and an optical system and arranged inside the chamber, and which is adapted to observe the microplates in the chamber with use of the microscopic observation device (see, for example, the publication of JP-T No. 2002-538477, JP-A No. 2003-93041, JP-A No. 2003-21628). The incubator makes it possible to observe the microplates in the chamber without opening the door of the chamber, so that interior ambient conditions of the chamber 91 are not altered.
However, with the conventional incubator which is adapted to automatically transport the microplates in the chamber, for the observation of the sample being cultured, the microplate into which the sample is injected needs to be delivered from the microplate accommodating rack to the microplate inlet and to be withdrawn from the inlet to the outside. After the observation the microplate must be transported to the interior of the chamber, and be returned to the original microplate accommodating portion. Accordingly there arises the problem that the observation of the sample takes much time, and the internal ambient conditions of the chamber are altered because the inlet is opened every time the microplate is moved into or out of the chamber.
On the other hand, with the incubator having arranged inside the chamber the microscopic observation device of the microplate, while internal ambient conditions of the chamber are not altered, there is the problem that high internal humidity of the chamber causes damage to the camera and optical system such as lenses constituting the microscopic observation device.