Patent Application
20070268492
The described and other advantages of the invention will become apparent from the following detailed description and by referring to the drawings where:
a illustrates an illumination source with a cavity according to the invention,
b illustrates an exemplary form of the inner surface of a cavity wall,
a illustrates an exemplary illumination arrangement according to the invention. The arrangement comprises a light source 282, such as a flash lamp. It also comprises a cavity tube 285 with side walls. The front opening 286 of the cavity tube collects light beams from the front area of the light source 282. There is also a reflector 284 which reflects the light beams that enter to the back side of the light source. The light beams reflected by the reflector also enter the opening 286 of the cavity tube.
The side walls of the cavity tube have reflecting inner surfaces. The reflectivity of the inner surfaces is preferably very high, i.e. close to 100% and at least 90%. The side walls are preferably reflective in their substantially whole inner surface. Thus the light beams collected from the opening 286 into the tube either travel directly through the tube or are either reflected at the inner surfaces once or several times before reaching the output opening 287 of the tube. Since there is very small attenuation in reflection, the light beams which have entered the front opening 286 will leave the opposite opening 287 of the tube almost without attenuation.
The cross section of the cavity tube preferably increases in the main direction of the light. Thus in the
It is preferable that the output opening of the cavity tube has approximately same size and form as the measurement area on the sample plate 202 of the equipment. Thus the light is directed evenly throughout the measurement area. On the other hand, it is not preferable that the cross section of the cavity tube would decrease in the main direction of the light because due to the angle of the side walls part of the light could then be reflected back to the light source.
In order to further improve the homogeneity of the illumination on the measurement area, it is preferable to have an uneven inner surface at the side walls of the cavity tube.
It is possible to include a filter or other optical components between the light source and the front opening of the cavity tube. It is also possible to integrate the back reflector and the cavity tube into a single part and thus avoid an intermediate area where some of the light can escape to the surroundings. The tube can be produced of many alternative materials, such as plastic or metal. The reflecting inner surface is preferably achieved by coating.
The collimated light received from the opening is reflected by a first mirror 106 and thus directed into a second cavity tube 370. The light is further collimated and homogenized within the cavity tube. The light received from the cavity tube 370 is directed to the sample plate 102 via a beam splitter 108. The sample plate 102 is preferably a microtitration plate. There may also be an optical excitation filter 358 between the cavity 385 and the mirror 106.
If the sample is excited from below the sample plate the mirror 106 is turned away from the light path. The excitation light thus enters the sample plate via a third cavity tube 371, mirror 107, a fourth cavity tube 372 and mirror 109. The cavity tubes 371 and 372 also collimate and homogenize the light before entering the measurement area. The cavity tube 371 has its side walls in a slight angle, whereas the cavity tube 372 has straight side walls.
a and 3 show cavities which have straight middle lines or main axis. However, it would also be possible to have bends in the cavity tube. In
In order to further homogenize the light distribution, it is possible to use mirrors with uneven surface. In
The detection part of the equipment of
a illustrates a further exemplary embodiment of an illumination arrangement according to the present invention. Light from a light source 482 is directed via a mirror 403 through a filter 458 to a second mirror 404. The second mirror reflects the light into a long cavity pipe 485. The second mirror 404 preferably has an uneven surface for homogenizing the light. The mirror has a convex, ball-surface-shaped area in the middle of the mirror, which further makes the distribution of light more uneven. A perspective view of the mirror 404 is illustrated in
The light which has been collimated and homogenized within the cavity pipe is further reflected with a mirror 106 and led to a second cavity pipe 470. The light is then directed to a microtitration plate 102 via a beam splitter 108. In the arrangement of
It is also possible to use more than one light source. Patent document U.S. Pat. No. 6,377,346 B1 discloses suitable arrangements for collecting light from several light sources. In an arrangement according to the present invention the light from the several light sources would be directed to the sample(s) via a cavity.
In this patent specification the structure of the components in an optical measurement instrument is not described in more detail as they can be implemented using the description above and the general knowledge of a person skilled in the art.
An optical instrument includes control means for performing the optical measurement process. The control of the measuring process in an optical measurement instrument generally takes place in an arrangement of processing capacity in the form of microprocessor(s) and memory in the form of memory circuits. Such arrangements are known as such from the technology of analyzers and relating equipment. To convert a known optical instrument into equipment according to the invention it may be necessary, in addition to the hardware modifications, to store into the memory means a set of machine-readable instructions that instruct the microprocessor(s) to perform the control of the illumination source, detection means etc. according to the properties of the inventive illumination arrangement and method described above. Composing and storing into memory of such instructions involves known technology which, when combined with the teachings of this patent application, is within the capabilities of a person skilled in the art.
Above, an embodiment of the solution according to the invention has been described. The principle according to the invention can naturally be modified within the frame of the scope defined by the claims, for example, by modification of the details of the implementation and ranges of use.
For example, although the described embodiment of the invention utilizes the simultaneous measurement of all samples of a sample plate, it is also possible to use the inventive illumination in equipment where only part of the samples or only one sample on the plate is measured at a time.
Although the invention is described with an arrangement where the light source and the detector are located on the bottom measurement head, there is no reason why their location on the top measurement head should not work. It is also possible to use illumination from above and detection from below the sample or vice versa.
It is also possible to use cavity tubes of many various forms, including rectangular, circular and elliptical cross section forms. Although the described embodiments had tubes with a size of cross section increasing towards the sample, it would also be possible to use a cavity tube with substantially straight side walls.
Also, although the invention has been described with reference to the various microtitration plates it is equally applicable to any form of sample matrixes.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20060495 | May 2006 | FI | national |
