CA1184652A - Optical analyser with a grating-monochromator for the near infrared range - Google Patents
Optical analyser with a grating-monochromator for the near infrared rangeInfo
- Publication number
- CA1184652A CA1184652A CA000398938A CA398938A CA1184652A CA 1184652 A CA1184652 A CA 1184652A CA 000398938 A CA000398938 A CA 000398938A CA 398938 A CA398938 A CA 398938A CA 1184652 A CA1184652 A CA 1184652A
- Authority
- CA
- Canada
- Prior art keywords
- light
- optical
- monochromator
- grating
- path
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000003287 optical effect Effects 0.000 title claims abstract description 35
- 230000005540 biological transmission Effects 0.000 claims abstract description 7
- 230000007246 mechanism Effects 0.000 claims abstract description 6
- 238000005259 measurement Methods 0.000 claims description 2
- 238000000034 method Methods 0.000 abstract description 7
- 230000035945 sensitivity Effects 0.000 abstract description 5
- 239000000126 substance Substances 0.000 description 4
- 238000010521 absorption reaction Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000005286 illumination Methods 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 230000003595 spectral effect Effects 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 102000004169 proteins and genes Human genes 0.000 description 1
- 108090000623 proteins and genes Proteins 0.000 description 1
- 238000012797 qualification Methods 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/28—Investigating the spectrum
- G01J3/42—Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry
Abstract
Abstract:
An optical analyser for the near infrared range contains a monochromator arranged in the path of light from a light source in an optical system including detectors as well as a microcomputer. A light-interrupting mechanism and an optical grating-monochromator are used, the optical grating being connected to a sine-mechanism.
The optical system includes a mirror for selecting between the transmission and reflection measuring methods, trans-mission and reflection detectors with light sensors being provided. The temperature of the light sensors is thermostatically controlled and the detectors contain amplifiers connected to the output of the light sensors.
The output of the amplifiers is connected to the input of a measuring system containing a band-filter, a demodulator and an A/D converter - all connected in series - while the A/D converter is connected to the microcomputer. The result is improved sensitivity over prior apparatus.
An optical analyser for the near infrared range contains a monochromator arranged in the path of light from a light source in an optical system including detectors as well as a microcomputer. A light-interrupting mechanism and an optical grating-monochromator are used, the optical grating being connected to a sine-mechanism.
The optical system includes a mirror for selecting between the transmission and reflection measuring methods, trans-mission and reflection detectors with light sensors being provided. The temperature of the light sensors is thermostatically controlled and the detectors contain amplifiers connected to the output of the light sensors.
The output of the amplifiers is connected to the input of a measuring system containing a band-filter, a demodulator and an A/D converter - all connected in series - while the A/D converter is connected to the microcomputer. The result is improved sensitivity over prior apparatus.
Description
~E___a ~ chromator for the near The invention relates to an optical analyser with a grating-monochromator for the near infrared range.
Optical analysers are known (eOg. the products of Technicon and Neotec) which focus the wide-band energy of a light source emitting in the near infrared range through a monochromator - the wavelength-selector of which is formed by a narrow-band interference fil~er - to the surface of a cuvette containing a prepared sample. With the aid of the monochromator the surface of the sample is lighted with a narrow-band light bundle with different wavelengths. The intensity of the reflected energy diffused from the sample is detected. Optical analysers for the near infrared range are based on a property of subs~ances, namely ~hat the most important organic components~ e.g. protein, oil, moisture, etc. absorb light at wavelengths characteristic for them. Accordingly there is a correlation between the reflected energy and the component characteristics of the substance tested.
Although the absorption maxima of the components differ depending on the wavelength, within the near infrared range they are rela~ively close to each other. Thus at the selected wavelength their absorption interaction ,~
. ~ i .
becomes effective. Elimination takes place by technical and mathema~ical measuring means, in general, with the aid of a microcomputer incorporated into the ins~rument.
However, the known optical analysers for the near infrared range can be operated only in wavelength ranges limited by ~he interference fil~ers. This restriction involves the disadvantage that there is no possibility of adapting methods that require adjustment of the wavelength to one differing from that proposed by the prod~cers. The forms of equipment are not all provided with a linear wavelength scale. ~oreover, in certain cases it is not even possible to calibrate directly in wavelengths, e.g.
with the Neotec apparatus.
Hitherto monochromators ensuring continuous selection of the wavelength (e.g. the grating-monochromators~ cannot be used in optical analysers for the near infrared range, since monochromators of this type - on a cost-level compatable with a system with an interference filter - can be constructed with about a tenth the light intensity.
The aim of the invention is to eliminate these drawbacks of the known systems and to develop an optical analyser for the near infrared range that contains an optical grating-monochromator, a detector system and a processing system that ensures a sensitivity corresponding to that of constructions having an inter~erence filter.
Simultaneously the invention should show the same advantageous features as the apparatus using a grating-monochromator. These are, as follows:
- a continuous spectrum can be produced in nanometer-stages;
- the apparatus is provided with a linear wavelength scale;
- the spectral band width is approximately constant within the wavelength range.
To this end the invention consists of an optical analyser for the near infrared range comprising: a light source having a filament, a spherical mirror for focussing an image of said filament along a path of light from the light source, 5~2 a monochromator arranged in said light path and having an optical grating connected to a sine-mechanism, a light beam interrupting mechanism interposed between said light source and said monochromator, an optical system in said light path after said monochromator and including a mirror operable for deflecting the light path for selecting between measurement by light transmission or light reflection, transmission and reflection detectors respectively provided with at leas~ one light sensor, means for thermostatically controlling the temperature of said sensors, each detector containing an amplifier connected to the output of a light sensor, and a measuring system having an input connected to the output of a said amplifiers, said measuring system having in series a band-filter, a demodulator and an A/D converter, said A/D
converter being connected to a micro-computer.
The field of application of the apparatus is large; it is suitable for displaying organic components of solid, liquid and gaseous substances.
The simultaneous determination of a maximum o~ 5iX
components requires an analysis time of less than one minute. The apparatus can be principally used for testing materials such as fodders, mixed fodders, foodstuffs and provisions.
The apparatus will be ~alibrated using the usual wet-chemical method.
The advantageous features of the pre~erred form of optical analyser according to ~he invention - in comparison to the traditional methods - are, as follows:
- operation does not require special qualification;
- chemicals are not needed;
- it is harmless to health;
- the apparatus operates quickly;
- operation at low costs becomes possible;
- accuracy corresponds to the accuracy of the traditional methods;
, .
- measuring results can be recorded by a printer;
- the software-system of the equipment enables the development of independent methods for the user;
- optical density is formed via the software.
A preferred embodiment o the invention is illustrated in drawings wherein;
Figure l shows the block schematic of the apparatus;
Figure 2 illustrates a monochromator and optical arrangement;
Figure 3 shows a sine-mechanism; and Figure 4 shows a control and measuring system.
In Figure l the c~mplete block schematic of the apparatus may be seen.
A microcomputer lO0 operated by a microprocessor controls a monochromator 104 and an optical system~ as well as a detector 105 and a sampling system. The apparatus is operated from keys lOl. Measuring results are displayed by a display 102, which - cooperating with a printer 103 - enables communication between the user and the instrumentO
The arrangement of the monochromator and the optics is seen in Figure 2.
A light source 1 is a wide-band halogen lamp with high energy. A spherical mirror 6 produces an image of the filament of the light source l above the filament. A
focussing lens 2 produces an image of the filament in the plane of an admission slit 8 via a diaphragm 3, a high pass edge filter 4, a flat mirror 5 and a focussing lens 7. The focussing lens 7 produces on the surface of a spherical mirror lO an image of the surface of the approximately uniformly illuminated focussing lens 2 revealed by the diaphragm 3. The spherical mirror lO
illuminates with a parallel light bundle an optical grating ll by which the radiation is diffracted. From the diffracted radiation the spherical mirror lO, produces after reflection by a flat mirror 16, in the plane ~4~
of an exit slit 17, a spectrum with the given linear dispersion~ The size of the admission slit 8 and the exit slit 18 define the spectral band-width of the light passing forward.
The high-pass edge filter 4 cuts undesired scattered light. Adjacent the admission slit 8 a light~interrupting wheel 9 is located, which is driven by a quartz-controlled synchronous motor 15. Simultaneously the light-interrupting wheel interrupts an optical coupling circuit 39 (Figure 3) which delivers a signal proportional with the momentary number of revolutions to the control unit of the detector system, In this arrangement the angular position of the optical grating ll defines the frequency of the light passing through the exit slit 18. By using a sine-mechanism 12 the possibility is provided that a linear correlation can be established between the number of steps - reckoned from the start position of a stepping motor 13 - and the wavelength of the light passing through the exit slit 17~
The sine-mechanism 12 is illustrated in detail in ~igure 3~ The stepping motor 13 rotates a threaded spindle 27 supported in bearings 38 via a clutch 26 with transverse articulation. A threaded nut 28 (secured rotationally~ is displaced together with a plate 29 and a switch arm 30 in a direction depending on the sense of rotation of the motor 13, ~o an extent proportional to the number of stepsO Under the influence of this movement the axis 35 of the optical grating ll suppor~ed in bearings 36 is turned by the lever 33 and the spring 34 in a play-free manner. The sine of the angular displacement is proportional to the number of steps of the motor 13.
This mechanism including the feature of the optical diffraction grating ll that with a fixed direction oE
illumination and observation the wavelength will be proportional to the sine of the angle of the optical grating 11 measured in a suitably selected direction, offers a solution or obtaining a linear wavelength scale.
The designation of the basic position is perfor~ed by the switch arm 30 and a switch 31.
Lenses 18, 20 (Figure 2) and a diaphragm 19 provide for uniform illumination of the sample contained in a cuvette 22 or 24~ By means of the mirrox 21 selecting the detector, the light bundle leaving ~he monochromator can be ro~ated by + 90~ Accordingly, one can choose between the trans-lQ mission or reflection measuring methods.
A switch 51 (Figure 4) on the axis of the mirror 21 signals the position of the mirror 21 to the electronics~
~igure 4 also shows a ~emperature control and measuring system. Both the transmission detector 52 and the reflection detector 53 are similarly constructed, light sensors 23, 25 being photoresistors.
Taking the sensitivity of the photoresistors and temperature~dependence of the dark current into consideration~ thermal stabilization is imperative. In the course of measuring there is a requirement that the threshold-sensitivity should be equal to 50 D (optical densîty~. The prerequisite of realization lies in that the temperature change of the light sensors 23, 25 should not be higher than l/100C/minute.
The temperature of the light sensors 23, 25 having been controlled by a thermostat 49 is observed by a temperature sensor 48. A circuit 45 of a temperature control unit 50 generating an error signal delivers a signal proportional to the temperature difference.
A complementary capacity - end stage 46 feeds a Peltier-cell 47 in such a manner that, in compliance with the sign of the error signal, the Peltier-cell 47 either heats or cools.
The light sensors 23, 25 deliver to the input of amplifier 40 or 41 an alternating voltage proportional to the light modulated by the light-interrupting wheel 9.
The amplifying factor of the amplifiers 40, 41 can be changed by the microcomputer 100 (ACC). Depending on the position of the switch 51 the output of the amplifier 40 or 41 is connec~ed to a measuring system 54. The input of the measuring system 54 is formed by a band-filter 42. The task of the band-filter 42 lies in suppressing the total noise-output resulting from the detector 52 or 53 in a proportion corresponding to the bandwidth of the band-filter 42. As a consequence - depending on the width of the band the sensitivity can be increased. The signal, being proportional to the phase difference of the input signal and the output signal of the band filter 42r keeps the frequency always at a predetermined value.
The alternating voltage signal appearing at the output of the band-filter 42 is transformed in a demodulator 43 into a direct voltage.
Analogue/digital conversion is performed by an A/D
converter 44 connected directly to the bus-system of the 2Q microcomputer 100.
Compared to the apparatus hitherto known, the following new features appear:
- with the aid of the light-interrupting system, the interrupting frequency can be adjusted to the optimum value and the sensitivity of the detectors increased by two orders of magnitude;
- the stability of the thermostat detectors can be increased by one order of magnitude (0.01 C/min) in comparison to known apparatus. The Peltier-elements are either heating or cooling and the required temperature stability can be achieved within some minutes instead of the heating time of 1-2 hours required up to now.
Optical analysers are known (eOg. the products of Technicon and Neotec) which focus the wide-band energy of a light source emitting in the near infrared range through a monochromator - the wavelength-selector of which is formed by a narrow-band interference fil~er - to the surface of a cuvette containing a prepared sample. With the aid of the monochromator the surface of the sample is lighted with a narrow-band light bundle with different wavelengths. The intensity of the reflected energy diffused from the sample is detected. Optical analysers for the near infrared range are based on a property of subs~ances, namely ~hat the most important organic components~ e.g. protein, oil, moisture, etc. absorb light at wavelengths characteristic for them. Accordingly there is a correlation between the reflected energy and the component characteristics of the substance tested.
Although the absorption maxima of the components differ depending on the wavelength, within the near infrared range they are rela~ively close to each other. Thus at the selected wavelength their absorption interaction ,~
. ~ i .
becomes effective. Elimination takes place by technical and mathema~ical measuring means, in general, with the aid of a microcomputer incorporated into the ins~rument.
However, the known optical analysers for the near infrared range can be operated only in wavelength ranges limited by ~he interference fil~ers. This restriction involves the disadvantage that there is no possibility of adapting methods that require adjustment of the wavelength to one differing from that proposed by the prod~cers. The forms of equipment are not all provided with a linear wavelength scale. ~oreover, in certain cases it is not even possible to calibrate directly in wavelengths, e.g.
with the Neotec apparatus.
Hitherto monochromators ensuring continuous selection of the wavelength (e.g. the grating-monochromators~ cannot be used in optical analysers for the near infrared range, since monochromators of this type - on a cost-level compatable with a system with an interference filter - can be constructed with about a tenth the light intensity.
The aim of the invention is to eliminate these drawbacks of the known systems and to develop an optical analyser for the near infrared range that contains an optical grating-monochromator, a detector system and a processing system that ensures a sensitivity corresponding to that of constructions having an inter~erence filter.
Simultaneously the invention should show the same advantageous features as the apparatus using a grating-monochromator. These are, as follows:
- a continuous spectrum can be produced in nanometer-stages;
- the apparatus is provided with a linear wavelength scale;
- the spectral band width is approximately constant within the wavelength range.
To this end the invention consists of an optical analyser for the near infrared range comprising: a light source having a filament, a spherical mirror for focussing an image of said filament along a path of light from the light source, 5~2 a monochromator arranged in said light path and having an optical grating connected to a sine-mechanism, a light beam interrupting mechanism interposed between said light source and said monochromator, an optical system in said light path after said monochromator and including a mirror operable for deflecting the light path for selecting between measurement by light transmission or light reflection, transmission and reflection detectors respectively provided with at leas~ one light sensor, means for thermostatically controlling the temperature of said sensors, each detector containing an amplifier connected to the output of a light sensor, and a measuring system having an input connected to the output of a said amplifiers, said measuring system having in series a band-filter, a demodulator and an A/D converter, said A/D
converter being connected to a micro-computer.
The field of application of the apparatus is large; it is suitable for displaying organic components of solid, liquid and gaseous substances.
The simultaneous determination of a maximum o~ 5iX
components requires an analysis time of less than one minute. The apparatus can be principally used for testing materials such as fodders, mixed fodders, foodstuffs and provisions.
The apparatus will be ~alibrated using the usual wet-chemical method.
The advantageous features of the pre~erred form of optical analyser according to ~he invention - in comparison to the traditional methods - are, as follows:
- operation does not require special qualification;
- chemicals are not needed;
- it is harmless to health;
- the apparatus operates quickly;
- operation at low costs becomes possible;
- accuracy corresponds to the accuracy of the traditional methods;
, .
- measuring results can be recorded by a printer;
- the software-system of the equipment enables the development of independent methods for the user;
- optical density is formed via the software.
A preferred embodiment o the invention is illustrated in drawings wherein;
Figure l shows the block schematic of the apparatus;
Figure 2 illustrates a monochromator and optical arrangement;
Figure 3 shows a sine-mechanism; and Figure 4 shows a control and measuring system.
In Figure l the c~mplete block schematic of the apparatus may be seen.
A microcomputer lO0 operated by a microprocessor controls a monochromator 104 and an optical system~ as well as a detector 105 and a sampling system. The apparatus is operated from keys lOl. Measuring results are displayed by a display 102, which - cooperating with a printer 103 - enables communication between the user and the instrumentO
The arrangement of the monochromator and the optics is seen in Figure 2.
A light source 1 is a wide-band halogen lamp with high energy. A spherical mirror 6 produces an image of the filament of the light source l above the filament. A
focussing lens 2 produces an image of the filament in the plane of an admission slit 8 via a diaphragm 3, a high pass edge filter 4, a flat mirror 5 and a focussing lens 7. The focussing lens 7 produces on the surface of a spherical mirror lO an image of the surface of the approximately uniformly illuminated focussing lens 2 revealed by the diaphragm 3. The spherical mirror lO
illuminates with a parallel light bundle an optical grating ll by which the radiation is diffracted. From the diffracted radiation the spherical mirror lO, produces after reflection by a flat mirror 16, in the plane ~4~
of an exit slit 17, a spectrum with the given linear dispersion~ The size of the admission slit 8 and the exit slit 18 define the spectral band-width of the light passing forward.
The high-pass edge filter 4 cuts undesired scattered light. Adjacent the admission slit 8 a light~interrupting wheel 9 is located, which is driven by a quartz-controlled synchronous motor 15. Simultaneously the light-interrupting wheel interrupts an optical coupling circuit 39 (Figure 3) which delivers a signal proportional with the momentary number of revolutions to the control unit of the detector system, In this arrangement the angular position of the optical grating ll defines the frequency of the light passing through the exit slit 18. By using a sine-mechanism 12 the possibility is provided that a linear correlation can be established between the number of steps - reckoned from the start position of a stepping motor 13 - and the wavelength of the light passing through the exit slit 17~
The sine-mechanism 12 is illustrated in detail in ~igure 3~ The stepping motor 13 rotates a threaded spindle 27 supported in bearings 38 via a clutch 26 with transverse articulation. A threaded nut 28 (secured rotationally~ is displaced together with a plate 29 and a switch arm 30 in a direction depending on the sense of rotation of the motor 13, ~o an extent proportional to the number of stepsO Under the influence of this movement the axis 35 of the optical grating ll suppor~ed in bearings 36 is turned by the lever 33 and the spring 34 in a play-free manner. The sine of the angular displacement is proportional to the number of steps of the motor 13.
This mechanism including the feature of the optical diffraction grating ll that with a fixed direction oE
illumination and observation the wavelength will be proportional to the sine of the angle of the optical grating 11 measured in a suitably selected direction, offers a solution or obtaining a linear wavelength scale.
The designation of the basic position is perfor~ed by the switch arm 30 and a switch 31.
Lenses 18, 20 (Figure 2) and a diaphragm 19 provide for uniform illumination of the sample contained in a cuvette 22 or 24~ By means of the mirrox 21 selecting the detector, the light bundle leaving ~he monochromator can be ro~ated by + 90~ Accordingly, one can choose between the trans-lQ mission or reflection measuring methods.
A switch 51 (Figure 4) on the axis of the mirror 21 signals the position of the mirror 21 to the electronics~
~igure 4 also shows a ~emperature control and measuring system. Both the transmission detector 52 and the reflection detector 53 are similarly constructed, light sensors 23, 25 being photoresistors.
Taking the sensitivity of the photoresistors and temperature~dependence of the dark current into consideration~ thermal stabilization is imperative. In the course of measuring there is a requirement that the threshold-sensitivity should be equal to 50 D (optical densîty~. The prerequisite of realization lies in that the temperature change of the light sensors 23, 25 should not be higher than l/100C/minute.
The temperature of the light sensors 23, 25 having been controlled by a thermostat 49 is observed by a temperature sensor 48. A circuit 45 of a temperature control unit 50 generating an error signal delivers a signal proportional to the temperature difference.
A complementary capacity - end stage 46 feeds a Peltier-cell 47 in such a manner that, in compliance with the sign of the error signal, the Peltier-cell 47 either heats or cools.
The light sensors 23, 25 deliver to the input of amplifier 40 or 41 an alternating voltage proportional to the light modulated by the light-interrupting wheel 9.
The amplifying factor of the amplifiers 40, 41 can be changed by the microcomputer 100 (ACC). Depending on the position of the switch 51 the output of the amplifier 40 or 41 is connec~ed to a measuring system 54. The input of the measuring system 54 is formed by a band-filter 42. The task of the band-filter 42 lies in suppressing the total noise-output resulting from the detector 52 or 53 in a proportion corresponding to the bandwidth of the band-filter 42. As a consequence - depending on the width of the band the sensitivity can be increased. The signal, being proportional to the phase difference of the input signal and the output signal of the band filter 42r keeps the frequency always at a predetermined value.
The alternating voltage signal appearing at the output of the band-filter 42 is transformed in a demodulator 43 into a direct voltage.
Analogue/digital conversion is performed by an A/D
converter 44 connected directly to the bus-system of the 2Q microcomputer 100.
Compared to the apparatus hitherto known, the following new features appear:
- with the aid of the light-interrupting system, the interrupting frequency can be adjusted to the optimum value and the sensitivity of the detectors increased by two orders of magnitude;
- the stability of the thermostat detectors can be increased by one order of magnitude (0.01 C/min) in comparison to known apparatus. The Peltier-elements are either heating or cooling and the required temperature stability can be achieved within some minutes instead of the heating time of 1-2 hours required up to now.
Claims (4)
1. An optical analyser for the near infrared range comprising: a light source having a filament, a spherical mirror for focussing an image of said filament along a path of light from the light source, a monochromator arranged in said light path and having an optical grating connected to a sine-mechanism, a light beam interrupting mechanism interposed between said light source and said monochromator, an optical system in said light path after said monochromator and including a mirror operable for deflecting the light path for selecting between measurement by light transmission or light reflection, transmission and reflection detectors respectively provided with at least one light sensor, means for thermostatically controlling the temperature of said sensors, each detector containing an amplifier connected to the output of a light sensor, and a measuring system having an input connected to the output of a said amplifiers, said measuring system having in series a band-filter, a demodulator and an A/D
converter, said A/D converter being connected to a micro-computer.
converter, said A/D converter being connected to a micro-computer.
2. An optical analyser as claimed in claim 1, compris-ing an admission slit in the optical path ahead of said light interrupting mechanism, and a focussing lens producing the image of the filament in the plane of said admission slit.
3. An optical analyser as claimed in claim 1 or 2, wherein the light interrupting mechanism is a light interrupting wheel driven by a motor.
4. An optical analyser as claimed in claim 1 or 2, wherein said sine-mechanism for actuating the optical grating has a stepping motor, the number of steps reckoned from the start position of the stepping motor and the wavelength of monochromatic light leaving said grating having a linear correlation.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| HU81801A HU182610B (en) | 1981-03-30 | 1981-03-30 | Near infra-red optical analyser built on lattice-type monochromator |
| HU801/81 | 1981-03-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1184652A true CA1184652A (en) | 1985-03-26 |
Family
ID=10951411
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000398938A Expired CA1184652A (en) | 1981-03-30 | 1982-03-22 | Optical analyser with a grating-monochromator for the near infrared range |
Country Status (6)
| Country | Link |
|---|---|
| AU (1) | AU8189682A (en) |
| CA (1) | CA1184652A (en) |
| DE (1) | DE3209490A1 (en) |
| FR (1) | FR2502780A1 (en) |
| HU (1) | HU182610B (en) |
| IT (1) | IT1151855B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3544512A1 (en) * | 1985-12-17 | 1987-06-19 | Bodenseewerk Perkin Elmer Co | POLYCHROMATOR |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1912772C3 (en) * | 1969-03-13 | 1975-06-19 | Deutsche Forschungs- U. Versuchsanstalt Fuer Luft- Und Raumfahrt E.V., 5300 Bonn | Ventilation-independent radiation measuring device |
| FR2067205A1 (en) * | 1969-11-25 | 1971-08-20 | Baloy Andre | |
| FR2070481A5 (en) * | 1969-12-05 | 1971-09-10 | Commissariat Energie Atomique | |
| US4270603A (en) * | 1978-12-06 | 1981-06-02 | Ford Aerospace & Communications Corp. | Non-contacting thermal energy transfer assembly |
-
1981
- 1981-03-30 HU HU81801A patent/HU182610B/en not_active IP Right Cessation
-
1982
- 1982-03-16 DE DE19823209490 patent/DE3209490A1/en not_active Ceased
- 1982-03-22 CA CA000398938A patent/CA1184652A/en not_active Expired
- 1982-03-25 AU AU81896/82A patent/AU8189682A/en not_active Abandoned
- 1982-03-26 FR FR8205168A patent/FR2502780A1/en active Granted
- 1982-03-26 IT IT20437/82A patent/IT1151855B/en active
Also Published As
| Publication number | Publication date |
|---|---|
| FR2502780B1 (en) | 1985-05-17 |
| AU8189682A (en) | 1982-10-07 |
| IT8220437A0 (en) | 1982-03-26 |
| FR2502780A1 (en) | 1982-10-01 |
| IT1151855B (en) | 1986-12-24 |
| DE3209490A1 (en) | 1982-12-16 |
| HU182610B (en) | 1984-02-28 |
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