Test tube with optically readable coding

Details Test tube with optically readable coding Test tube with optically readable coding

1999-01-29

2001-08-07

Reifsnyder, David A. (Department: 1723)

Chemical apparatus and process disinfecting, deodorizing, preser

Control element responsive to a sensed operating condition

C422S915000, C206S439000, C235S454000, C235S462010, C235S470000, C235S472010, C250S566000

Reexamination Certificate

active

06270728

ABSTRACT:

The present invention relates to a test tube, comprising a tubular container, which tubular container at its bottom end is provided with an optically readable coding such as a dot code.
A container resembling such a test tube is known from WO 94/02857.
A test tube in this case should be understood as meaning a container for storing substances, as well in liquid form, as in powder form as in solid form, for chemical analyses, sample storage etc. Such test tubes can range in size from small test tubes, for example test tubes with a capacity of 0.2 ml, to large test tubes with a capacity of 10 ml or more.
Test tubes are commonly used for storing samples, such as blood samples of humans and animals, for possible subsequent analysis. Such samples may be divided among a number of test tubes if necessary. In addition, many samples are stored for other purposes. In the case of all these applications it is extremely important to be able to code the test tubes, in order to be able to keep a record of the contents of each test tube. The test tubes are generally arranged in the racks in an 8×12 configuration, so that each rack contains 96 test tubes. It is known to allocate a position code to each test tube in the rack by numbering the rows and columns. The eight rows are then numbered, for example, A to H, while the twelve columns are numbered 1 to 12. In this way, depending on the position in the rack, each test tube can be given its own code, for example A1, C7, H9 etc. Such a coding is generally not indicated on the tubes, but along the sides of the rack. Such a coding may also be indicated on the tube itself, if desired, this being of benefit only if the tube does not form a fixed part of the rack. These codings are designed to be read with the human eye. These codings are applied directly to the transparent test tube, which has the disadvantage that in the case of certain substances the coding is very difficult or impossible to read.
A container bearing some resemblance to the test tube of the type mentioned at the beginning is known from International Patent Application WO 94/02857. This publication relates to a “reagent bottle identification and reagent monitoring system for a chemical analyzer”. In this case, in a chemical analyzer use is being made of reagent bottles which at their top end are provided with a narrowed neck and at their bottom end are provided with a dot code at the downward facing surface of the bottom. This dot code is applied to a printed label which can be fixed by means of an adhesive to the downward facing surface of the bottom. According to a preferred embodiment, each label here has a light-coloured background on which a contrasting pattern of dots is printed. As stated in this publication, smallest dot sizes with a diameter of approximately 850 &mgr;m can be achieved here, while the surface required for the dot code must have a diameter of at least approximately 13 mm.
The object of the present invention is to provide a coded test tube, preferably a uniquely coded test tube, in the case of which the coding is readable at all times.
This object is achieved according to the invention with a test tube comprising a tubular container, which tubular container at its bottom end is provided with an optically readable coding such as a dot matrix, characterized in that the optically readable coding is applied to an optically substantially opaque surface, in other words, an optically substantially opaque background with a surface bearing the coding. Applying the optically readable coding to an optically substantially opaque background ensures that the optical coding is readable at all times with an optical reading mechanism, irrespective of the substance present in the generally transparent test tube. If the surface or the background is not or is insufficiently optically opaque, errors could occur during reading of the code, as a result of reflections coming from the substance present in the test tube. By applying the optically readable coding at the bottom end of the test tube, simple automated reading of the coding with the aid of an optical reading mechanism is made possible. For the test tube need only be held with its bottom end towards an optical reading mechanism, which is then possible in principle while the test tube is still in a rack, even if a number of test tubes are situated next to each other in the rack.
In order to be able to read the optically readable coding from underneath with great certainty, it is advantageous according to the invention if the optically substantially opaque surface is substantially flat and faces downwards, and extends substantially in the crosswise direction of the tube. Making the surface flat ensures that the risk of errors during the automated optical reading of the coding is minimized by avoiding optical deformations, and providing the surface facing downwards at the bottom end of the tubular container ensures that the circumferential measurements of the tubular container can remain substantially unchanged.
Since, on account of their material properties, not all test tubes can be provided with an optically opaque surface, i.e. an optically opaque background, applied directly thereto, and not every test tube material is so suitable for direct application of a coding thereto, it is advantageous according to the invention if said surface is applied to a carrier part fixed to the bottom end of the tubular container. Such a carrier part according to the invention can be fixed to the tubular container if the tubular container comprises retaining means, such as a retaining lug or retaining recess, at its bottom end, but it is also very conceivable for the carrier part to be glued or stuck or pressed onto the tubular container.
According to a special, advantageous embodiment, the carrier part will be made of a material which is different from the material from which the tubular container is made and which is suitable for the application of the optically readable coding. This makes it possible to continue using materials which have proved very suitable for the actual test tube itself, such as in particular optically transparent materials, and still to provide said test tube with an optical coding which is easily readable in all circumstances.
In order also in particular to be able to provide very small test tubes—for example, having a diameter of approximately 8.5 mm and smaller—with a coding which is unique for the test tube in question, it is very advantageous according to the invention if the material of the carrier part is suitable for burning in the optically readable coding by means of a laser technique, which coding in this case is preferably a fine dot code. What is meant here by a fine dot code is a code in which the centre-to-centre distance between adjacent dots is less than 0.5 mm, preferably 0.4 to 0.35 mm or less. With such a laser technique, dots with a diameter of less than approximately 200 &mgr;m, for example approximately 150 to 175 &mgr;m, can be achieved in the case of a carrier part made of a material suitable for the purpose. An average person skilled in the art will be able to name widely varying suitable materials for the carrier part which not only permit the application of such a fine dot code by a laser technique which is known per se, but also provide an optically opaque background for trouble-free reading of the dot code. Polystyrene, possibly provided with a suitable filling agent or filling substance, can be mentioned as an example of such a suitable material. Another example which can be mentioned is ABS (acrylonitrile butadiene styrene), which in itself has a white basic structure and lends itself very well to burning in a very fine dot code by means of a laser technique. Other plastics. for example filled with titanium white or zinc white, seem suitable for burning in a very fine dot code by a laser technique, but plastic to which. TiO
2
-coated ground mica particles are added are also very suitable for this purpose.
The carrier part according to the invention can advantageously be a part

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