Optics: measuring and testing – By shade or color – With color transmitting filter
Reexamination Certificate
2001-09-07
2004-11-23
Font, Frank G. (Department: 2877)
Optics: measuring and testing
By shade or color
With color transmitting filter
C356S416000, C250S458100
Reexamination Certificate
active
06822741
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to the field of biochemical laboratory instrumentation for different applications of measuring properties of samples on e.g. microtitration plates and corresponding sample supports. More particularly the invention relates to the improved and more efficient instrumental features of equipment used as e.g. fluorometers, photometers and luminometers.
The routine work and also the research work in analytical biochemical laboratories and in clinical laboratories are often based on different tags or labels coupled on macromolecules under inspection. The typical labels used are different radioactive isotopes, enzymes, different fluorescent molecules and e.g. fluorescent chelates of rare earth metals.
The detection of enzyme labels can be performed by utilizing its natural biochemical function, i.e. to alter the physical properties of molecules. In enzyme immunoassays colourless substances are catalysed by enzyme to colourful substances or non-fluorescent substances to fluorescent substances.
The colourful substances are measured with an absorption, i.e. photometric measurement. In the photometric measurement the intensity of filtered and stabilized beam is first measured without any sample and then the sample inside one plate is measured. The absorbance i.e. the absorption values are then calculated.
The fluorescent measurement is generally used for measuring quantities of fluorescent label substance in a sample. The most photoluminescence labels are based on molecular photoluminescence process. In this process optical radiation is absorbed by the ground state of a molecule. Due to the absorption of energy the quantum molecule rises into higher excited state. After the fast vibrational relaxation the molecule returns back to its ground state and the excess energy is released as an optical quantum. Due to losses in this process the average absorbed energies are higher than the average emitted energies.
A further measurement method is chemiluminescence measurement where emission of a substance is measured from a sample without excitation by illumination. Thus any photoluminometer can also be used as a chemiluminometer.
The typical instruments in analytical chemical research laboratories are the different spectroscopic instruments. Many of them are utilizing optical region of electromagnetic spectrum. The two common type of instruments are the spectrophotometers and the spectrofluorometers. These instruments comprise usually one or two wavelength dispersion devices, like monochromators. The dispersion devices make them capable to perform photometric and fluorometric measurements throughout the optical spectrum.
FIG. 1
illustrates an advanced prior art optical analyser, especially the optical components and the different optical paths. The instrument has two illumination sources, a continuous wave lamp (cw-lamp)
112
a
and a pulse lamp
112
b
. The cw-lamp can be used for continuous wave photoluminescence excitation and for absorption measurements.
Infrared part of radiation from the cw-lamp
112
a
is absorbed by a filter
104
, and after transiting a stray-light aperture plate
105
, the optical radiation is collimated with a lens
115
a
through an interference filter
114
a
located in a filter wheel
114
.
The light beam is focused with a lens
113
a
, similar to the lens
114
a
, into a light guide
118
, which isolates the measuring head thermally and mechanically. It also shields the measuring unit for the stray light from the cw-lamp. The optical radiation from an output aperture plate
106
of a light guide
118
is collimated with a lens
107
, similar to the lens
115
a
. The radiation beam is reflected by a beam-splitter mirror
141
inside a mirror block
140
, and passed through a sample well
181
and through an entrance window
122
of a photometric detector unit
132
.
The mirror block
140
is located on the upper side of the sample. Its function is to reflect the horizontal light beam from the selected lamp downwards to the sample and to reflect a portion of this beam by a mirror
143
into a reference photodiode
119
, and also to allow the emission from the sample to travel upwards to the detector
132
.
The emission unit comprises optical components, which are lenses
133
,
135
, a filter
134
a
in filter slide
134
, a combined shutter and aperture slide
136
and a detector
132
, such as a photo-multiplier. The detector
132
is used in the fast photon counting mode where the pulses from photo-multiplier anode are first amplified and then fed through a fast comparator
191
and gate
192
counter
193
. The comparator rejects the pulses, which are lower than the pre adjusted reference level. The fast counting electronics is equipped with a gate in the front of the counter. This gate is used in overall timings of the measurements.
The pulse-lamp unit is used in time-resolved photoluminescence measurement for long-living photoluminescence emission. It comprises a second lamp
112
b
, lenses
115
b
,
113
b
, and optical filters
114
b
in a filter slide for wavelength isolation. When this second lamp is used the mirror
141
must be rotated by 90 degrees in order to reflect the radiation to the sample. This can be achieved by using different optical modules for the two lamps.
There are certain limitations related to the prior art technology. It is often required to make several measurements from same samples, e.g. measuring of two or more photoluminescence emissions, as well as absorption and chemiluminescence measurements may be required. With the prior art instruments it is necessary to make the different measurements successively, and it may be necessary to make changes in the optics of the instrument between the different measurements. Therefore performing such measurements from a large number of samples tends to take a very long measurement time with the prior art instruments, and the reliability of the measurement results is not optimal.
There are also instruments, which have two measurement heads; a top measurement head and a bottom measurement head. Such instruments are disclosed e.g. in documents U.S. Pat. No. 6,187,267 and U.S. Pat No. 5,933,232. With this kind of instrument it is possible to make measurements also from below the sample, so this kind of instrument is more versatile for performing different measurements. However, the prior art instruments are not capable of performing different measurements simultaneously, nor capable of performing dual emission measurements. Performing different measurements successively from a large number of samples tends to take a long time.
SUMMARY OF THE INVENTION
The object of the present invention is to provide an optical instrument for laboratory measurements, wherein the described disadvantages of the prior art are avoided or reduced. The object of the invention is therefore to achieve a measurement instrument with improved efficiency for performing measurements from samples.
The object of the invention is achieved by providing an optical measurement instrument where there is an interface for a changeable optical module, the interface being adapted for at least one excitation beam and at least two emission beams. The object is further achieved by a changeable optical module for a measurement instrument, the module comprising a preferably dichroic mirror for dividing an emission beam into two emission beams, and a preferably dichroic mirror for separating the optical paths of emission and excitation beams. The invention allows performing various types of measurements by changing an optical module. The change of module and related parameters can be performed automatically controlled by software. It is also possible to easily upgrade the instrument for new types of measurements by just providing the instrument with a new optical module and the related software.
An optical measurement instrument according to the invention for measuring samples, comprising an illumination source for forming an excitation beam, a first detector for detecting a fir
Aronkytö Petri
Harju Raimo
Myllynpää Asko
Font Frank G.
Punnoose Roy M.
Wallac Oy
Young & Thompson
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