Optics: measuring and testing – By dispersed light spectroscopy – Utilizing a spectrometer
Reexamination Certificate
1998-11-09
2001-01-23
Font, Frank G. (Department: 2877)
Optics: measuring and testing
By dispersed light spectroscopy
Utilizing a spectrometer
C300S013000
Reexamination Certificate
active
06177991
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a measuring device with the capability of automatically exchanging samples, comprising an automatic sample changer on which a plurality of samples can be selectably set and a main body which contains a control unit for controlling the operation of this automatic sample changer for selecting a sample. Such a measuring device can be utilized in a spectrometer using an automatic sample changer having a plurality of samples set along the outer periphery of a rotatable circular disk.
When it is desired to measure a plurality of samples continuously, one frequently uses an accessory device such as an automatic sample changer or an automatic sampler adapted to automatically select or exchange a plurality of samples and transport them to a specified position for the measurement. With the help of such an accessory device, the user can set up all the desired samples prior to the beginning of the measurements and need not necessarily be present when the measurements are actually being carried out until automatic measurements of all the samples are completed. Such a procedure is particularly effective if the samples to be measured are relatively stable chemically and do not require any chemical pretreatment.
In general, most samples suitable for infrared spectrometry satisfy these conditions, and automatic measurements are frequently carried out by using an automatic sample changer.
FIG. 4
shows schematically a prior art Fourier transform infrared spectrometer which may be roughly described as comprising a main body
10
including a sample chamber
13
and an automatic sample changer
20
which is detachably attached to this sample chamber
13
. Infrared light emitted from a source
11
inside the main body
10
is introduced to an interferometer (the “optical means”)
12
. The interferometer
12
includes a beam splitter
121
, a fixed mirror
122
and a longitudinally slidable mobile mirror
123
. The reflected beams from the fixed mirror
122
and the mobile mirror
123
are lead by the beam splitter
121
to propagate in a same direction, resulting in a coherent infrared light beam with amplitude which varies time-wise. This coherent infrared light beam is lead into the sample chamber
13
and directed to one of the sample cells
22
on the automatic sample changer
20
. The gas, liquid or solid sample inside the sample cell
22
absorbs the light with characteristic wavelengths, depending on its constituents. The light which passes through the sample cell
22
is lead out of the sample chamber
13
and detected by a detector
14
. What is outputted from the detector
14
is an intensity signal as a function of time, and this is Fourier-transformed to obtain a relationship between the frequency (or wavelength of light) and the signal intensity. Thus, the signal outputted from the detector
14
is Fourier-transformed by a signal processor
15
which serves to generate an absorption spectrum. If necessary, this absorption spectrum may be used to calculate the spectral absorptivity and transmissivity.
FIG. 5
shows an example of automatic sample changer
20
having a plurality of sample cells
22
arranged in a circle along the outer periphery of a circular rotary disk
21
. The central shaft of this disk
21
is driven directly or indirectly (such as through a suitable decelerating mechanism) by a motor
23
to be rotated. Control signals MC to the motor
23
for selecting a sample cell
22
is provided from a control unit
30
through connectors
24
a
and
24
b.
In general, automatic sample changers of different kinds are provided such as those for carrying different numbers of sample cells, depending, for example, on the sizes of the samples and those having a selected reference sample already set in one part such that a most suitable automatic sample changer can be selected and set inside the sample chamber
13
according to the purpose of and the target for the measurement. If the number of sample cells is different, for example, the angular separation &thgr; between mutually adjacent sample cells
22
will also be different and hence the control unit
30
is required to control the motion of the motor
23
differently to select a sample cell, depending on the kind of automatic sample changer which has been set.
With a prior art device of this type, therefore, the user had to input through an input device
16
(such as a keyboard) the distribution of the sample cells (such as their angular separations &thgr; and their number) or the position of the reference sample, depending on the type of the installed automatic sample changer. Such an input work is a troublesome procedure and since the user seldom remembers the method of such operations, the user is compelled to make the input by consulting a document such as an instruction book. In summary, such a prior art device was not efficient.
In view of the above, it has been proposed to provide the control unit
30
with the function of identifying the kind of automatic sample changer which has been installed. This may be accomplished, for example, by providing each automatic sample changer
20
with a connector having a plurality of pins such that each automatic sample changer has a different connection scheme for the pins. As an automatic sample changer
20
is set inside the sample chamber
13
and a connecter from the control unit
30
is engaged with the connector on the automatic sample changer, the control unit
30
can identify the type of the automatic sample changer
20
from the condition of the connection of each pin.
With this method, however, the number of different kinds of automatic sample changer that can be identified is limited, depending on the number of the pins on the connector. Since the control unit
30
can identify only the kinds of automatic sample changer which have originally been encoded, it cannot identify any automatic sample changer of a novel structure which did not exist when the encoder was prepared. In other words, extendability of use is very poor with such a scheme.
SUMMARY OF THE INVENTION
It is therefore an object of this invention in view of the above to provide an improved measuring device capable of using many different kinds of automatic sample changers without the necessity of a cumbersome input procedure.
A measuring device embodying this invention, with which the above and other objects can be accomplished, may be characterized as comprising an automatic sample changer for carrying a plurality of samples thereon and a main body. The automatic sample changer may include a rotary circular disk rotatable around its central shaft by a stepping motor for changing positions of the samples thereon which, for example, may be positioned in a circle around the central shaft of the disk. A memory device preliminarily storing control data for each of different kinds of automatic sample changers is provided.
The automatic sample changer, when connected to a control unit in the main body, serves to receive control signals for controlling motions of the motor and to transmit data stored in the memory device through a connector. The main body contains a readout means for reading out the control data from the memory device, a drive control means for using the control data received by the readout means to generate the control signal and to transmit the generated control signal to the automatic sample changer.
REFERENCES:
patent: 4024395 (1977-05-01), Mueller et al.
patent: 4582990 (1986-04-01), Stevens
Font Frank G.
Majestic, Parsons, Siebert & Hsue P.C.
Ratliff Reginald A.
Shimadzu Corporation
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