An analysis of a tangible component in a biological sample in the medical field requires a classification of various kinds and types of tangible components. Therefore, there has been a problem such as that: (i) it takes a long time to train an expert medical technologist; (ii) it is necessary to observe a tangible component by using a microscope for a long time; and (iii) a result of an analysis varies greatly between individuals and facilities. Examples of such the analysis of the tangible component in the biological sample encompass an analysis of a urinary sediment component. The analysis of the urinary sediment component is constituted by a plurality of steps such as: (i) subjecting a urinary sample to centrifugation so as to separate the urinary sample into a sediment component and a supernatant component; (ii) removing the supernatant component; (iii) taking out a part of the sediment component, smearing the part of the sediment component onto a slide glass, and sealing the slide glass with a cover glass, so as to prepare a preparation; and (iv) analyzing the preparation by using an optical microscope. Generally, these steps are carried out manually by a person. Therefore, these steps put a heavy burden to a medical technologist. Further, there is a problem in accuracy in an analysis and a judgment because the result obtained by the analysis and the judgment varies greatly between medical technologists.
In order to solve the foregoing problems, an analyzer for analyzing a tangible component in a biological sample in an automated manner was developed recently. Such an analyzer is getting more and more used in the clinical field. For example, Patent Document 1 discloses a urinary tangible component classification device including means for (i) automatically focusing on a tangible component in liquid to be examined (particularly, urine) and (ii) taking an image of the liquid to be examined (urine) placed on a light-transmitting plate or contained in a flow cell, for the purpose of minutely and accurately classifying the tangible component in the urine. Further, in the urinary tangible component classification device, the means is provided with an automatic focusing function for automatically focusing on a tangible component in liquid to be examined.
Further, for example, Patent Document 2 discloses a microscope system for setting in advance, as a focus point, a position which is at a predetermined distance from a starting point set at a bottom surface of a container, for the purpose of observing a cell attachment, although an objective of this technique is not to analyze a tangible component in a biological sample.
Furthermore, as another automatic focusing technique, Patent Document 3 provides such a method that (i) a position where an object to be observed is assumed to be present is set in advance, (ii) a focusing operation is carried out at the position thus set, and (iii) if a focus state is not obtained, the focusing operation is carried out finely around the set value until the focus state is obtained.
The analyzer disclosed in Patent Document 1, however, analyzes a tangible component in a biological sample by using a Flow cytometer, and does not prepare a sample (e.g., a preparation) on which an object to be examined is applied. Therefore, without any modifications, the analyzer cannot be used as a device for carrying out an analysis by preparing a sample (e.g., a preparation) on which an object to be examined is applied.
A tangible component in a biological sample is not fixed in a preparation, but is flowing in the preparation. Because the technique disclosed in Patent Document 2 is for observing a sample fixed in a preparation, the technique is not suitable for an analysis of a sample which is flowing in a preparation. Further, in a biological sample, there are various kinds of tangible components having different shapes and colors. Therefore, the tangible components do not have a certain focus position which is fixed. For this reason also, it is impossible to use the technique disclosed in Patent Document 2 for analyzing a tangible component in a biological sample.
The technique disclosed in Patent Document 3 is established on the premise that a cell to be observed is present in a sample. However, in an analysis of a tangible component in a biological sample, it is unknown whether or not the tangible component is present in the biological sample. For this reason, it is also impossible to use the technique disclosed in Patent Document 3 for the purpose of analyzing a tangible component in a biological sample.
As well as an analysis of a tangible component in a biological sample, an analysis of a tangible component in a non-biological sample (such as a sample for a water quality test) has the foregoing problems.
Therefore, there has been a strong demand for development of an analyzer available for both biological sample and non-biological sample, which analyzer (i) judges whether or not a tangible component is present in a sample in a preparation and (ii) if the tangible component is present, analyzes the tangible component with efficiency and high accuracy.
[Patent Document 1]
Japanese Unexamined Patent Application Publication, Tokukai, No. 2001-255260 (published on Sep. 21, 2001)
[Patent Document 2]
Japanese Unexamined Patent Application Publication, Tokukai, No. 2001-296478 (published on Oct. 26, 2001)
[Patent Document 3]
Japanese Unexamined Patent Application Publication, Tokukaihei, No. 11-95091 (published on Apr. 9, 1999)