JPS63305234A - Improvement in near infrared device for measuring organic component of substance - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an apparatus for quantitative near-infrared analysis of organic components present in substances.

Near-infrared quantitative analysis devices for measuring components such as fats and oils present in sample materials are well known and commercially available.

This near-infrared quantitative analyzer analyzes the near-infrared energy reflected from the surface of a sample to obtain quantitative data about the organic components present in the substance. This type of equipment requires that the surface of the sample be very homogeneous and therefore the material must be ground into a fine powder of a certain particle size; for some samples, for example sunflower seeds, this may be It is virtually impossible.

Another type of near-infrared quantitative analyzer analyzes the energy transmitted through a sample of fixed thickness, e.g. 20), to obtain quantitative data about the amount of organic components present within the sample. There is. An example of this type of device is described in Robert D. Rosenthal and Scott Rosenthal, U.S. Pat. ing. In this type of transmission measurement method, there is no need to grind the sample into a powder with uniform particle size as in the case of the reflection measurement method described above.However, in the transmission measurement method, two opposing surfaces of the sample, That is, it is necessary to have access to the surface on the side where near-infrared energy enters the sample and the opposite surface where the energy exits the sample.

Depending on the application, such as the measurement of human body fat, it is not possible to meet the conditions for reflection-type measurement, in which the sample is pulverized into a uniform powder, or the conditions for transmission-type measurement, in which two sides are measured. Other forms of near-infrared quantitative analysis equipment have been found to be effective. Such a device is
A near-infrared and optical interaftance system in which a light source is directed in a circular pattern into the sample material by an illumination tube and a detector is located in the center of the illumination tube.
This method utilizes the principle of eraCtanCe). When near-infrared radiation enters the sample material, the intarftance sends a portion of the energy back out of the material to the center of the illumination tube, where it is detected by a detector and used for reading. A commercially available device utilizing this technology is published in U.S. Pat. No. 4,633,0 by Glenn K. Rosenthal, Jeffrey D. Stevens and Robert D. Rosenthal.
No. 87 “Near infrared device for measuring organic components of substances” (
It is manufactured and sold based on the patented mortar (December 30, 1986). In order to apply the principle of infrared interftance, such devices use a plurality of infrared light emitting diodes (IREDs) of a predetermined wavelength to provide a light source through a translucent tube. Such a device consists of multiple pairs of matched I
Until now, manufacturing such devices using RED's has required selecting the IRED for the specific wavelength used to make the measurements. Due to manufacturing tolerances, the exact center wavelength of the IRED is typically different for each production batch, so each production batch is selected to
In addition to matching IRED pairs, these I R
It is necessary to ensure that the ED has a particular center wavelength that is most suitable for making measurements. If the IRED production process is such that it causes slight changes in the center wavelength,
In order to select a few I REDs with the required wavelength,
There are such time-consuming tests that require testing a large number of TREDs, and inappropriate IREIs.
)! J' is wasted, which considerably increases the production cost of the device.

Therefore, of the device! jli! Unnecessary sorting and IR during manufacturing
There remains a need in the art to improve near-infrared interaffection devices to eliminate waste in EDs.

The present invention interposes an optical filter with a narrow passband between the IRED and the illumination tube to provide a narrow band of predetermined wavelengths for all determination. By making it possible to obtain near-infrared rays in the IP range, it is possible to eliminate the need for time-consuming and wasteful selection of IREDs during the manufacture of the above-mentioned near-infrared interference device. In the narrow band optical filter, a specific wavelength is selected regardless of the center wavelength of the near-infrared light emitting diode.

The present invention can be applied to near-infrared interaffetance analyzers such as those described in the above-mentioned US Pat. No. 4,633,087. Referring to FIG. 1, such a device 10 is of hollow cylindrical shape, the hollow tubular member 12 having a desired bandwidth, i.e. from about 800 to about 1
It has walls made of a translucent solid material selected to transmit and absorb very little near-infrared energy at 100 nanometers. Suitable materials for forming tubular member 12 include, but are not limited to, translucent nylon, translucent polytetrafluoroethylene, and the like.

Means serving as at least one point light source of near-infrared rays of a predetermined wavelength is disposed at the upper end 13 of the tubular member 12. The near-infrared point light source means at the upper end 13 of the tubular member 12 transmits near-infrared rays of a predetermined wavelength emitted from the point light source means from the upper end 13 to the flat bottom surface 14 of the tubular member 12. be placed in such a position that it will be The near-infrared point light source means preferably consists of a plurality of pairs each of two infrared light emitting diodes (IREDs), preferably the TREDs are arranged symmetrically at the upper end 13 of the tubular member 12. be done. Two paired IREs
D are of substantially the same wavelength and are located approximately 180'l apart in the circumferential direction of the upper end 13 of the tubular member 12.

The preferred embodiment shown in FIG.
Three pairs of D are shown, 16.16', 17.17', 18 and 18'. In other embodiments, two or four pairs of IREDs may be used as point light source means.

The translucent tubular member 12 is made to have an appropriate length to obtain sufficient light scattering inside so as to smooth out the pulsating light source, so that the light from the IRED is transmitted through the tubular member 12. For example, a suitable length for an extruded translucent nylon tube with a diameter of 1 inch and a wall thickness of 178 inches is about 1-3/4 inches.

To minimize near-infrared loss, the tubular member 12 is preferably no longer than necessary to uniformly smooth the pulsating light source. This can be easily determined using an external viewer (night scope). Tube dimensions can also be determined by observing the near-infrared light passing through the tube and cutting the tube until the light appears uniform.

Next, move the silicon detector along the end of the tube and
Check whether the output is uniform.

For light shielding, the cylindrical wall of the transparent tubular member 12 is shielded on the outside with an outer tubular opaque shield 20 and on the inside with an inner tubular opaque shield 22. Upper end 1 of tubular member 12
3 is also shielded from ambient light by a top cover (not shown).

A photodetector 28 capable of detecting near-infrared rays is disposed at the inner bottom end of the tubular member 12. Internal tubular shield 22
is provided between the detector 28 and the translucent tubular member 12, and forms an opaque mask that prevents near-infrared rays from the tubular member 12 from directly entering the detector 28. The photodetector 28 generates an electrical signal when it detects near-infrared rays.

Photodetector 28 is connected to the input of electrical signal amplifier 30 by suitable conductive means 33.

This amplifier 30 may be an inexpensive signal amplifier, and the detector 2
8 amplifies the signal generated by the detector in response to the detected radiation. Preferably, the detector 28 is connected to the tubular shield 22
Placed within. Amplifier 30 amplifies the signal generated by detector 28 and sends the signal via conductive line 34 to read box 32 . In this readout box, a display 36 directly displays the percentage value of fat in the sample material S.
may be provided.

Two conductive windows transparent to near-infrared energy are grounded directly to the electronics of the device. This window 29 is provided in front of the photodetector 28.

The conductive window is intended for shielding from electromagnetic interference commonly found in industrial and equipment premises.

The device described herein is of the type that utilizes the principle of interftance, which is well known in the art and is distinct from reflectance and transmittance. In the interftance method, light from a light source is shielded from a detector by an opaque member, and the detector detects the interference of the light with the test object.

The system works by employing multiple readings for each IRED and data processing integral analog to digital converter 40 to reduce noise.

This converter 40 is connected to a digital processor 41 which is connected to the reading box 32.

In operation, the window 29 is placed toward the surface of the test object S. The light emerging from tubular member 12 interacts with test object S and is detected by detector 28, which in turn generates an electrical signal, which is processed as described above.

In all respects described above, this device is similar to that disclosed in the aforementioned US Pat. No. 4,633,087. This device includes an upper end portion 1 of a translucent tubular member 12.
Infrared light emitting diodes (IREDs) 16.16'' are placed at intervals of 60゛ on the circumference of 3.

17.17', 18. and 18' are used, and IREDs of the same wavelength are provided at intervals of 180°. As mentioned above, IREDs have different exact center wavelengths depending on their production batches, so conventionally, in the manufacture of such devices, it has been difficult to obtain a specific wavelength due to the difference in the exact center wavelengths of IREDs depending on production batches. A tedious classification of IREDs was required, resulting in considerable waste and expense.

The present invention is advantageous in that by providing a narrow bandwidth optical filter (as shown schematically in FIG. 2) immediately before each near-infrared light emitting diode, e.g. , eliminating the above-mentioned classification and waste. A filter 23 is provided between each IRED and the tubular member 12 in order to convert near-infrared rays emitted from each IRED into r-rays, so that only near-infrared rays with a narrow bandwidth of a predetermined wavelength pass through the filter and are transmitted to the tubular member 12. You can go inside. By using a narrow bandwidth optical filter, a particular wavelength can be selected depending on the center wavelength of the particular near-infrared light emitting diode being used. Each pair of diodes includes a filter that passes near-infrared rays of the same predetermined wavelength. When the present invention is applied to the device shown in FIG. 1, the optical filters corresponding to the first and second pairs of near-infrared light emitting diodes 16. Near-infrared rays having a wavelength of nanometers are passed through the tubular member 12 . Optical filters associated with the remaining pair of near-infrared light emitting diodes 18 , 18 ′ pass near-infrared light at wavelengths of approximately 880-890 nanometers into tubular member 12 .

Another advantage of using narrow bandwidth filters in the present invention is that the filters can more clearly separate the measurement bands;
This means that accuracy and measurement repeatability are improved. This is based on prior art U.S. Pat. No. 4,633,
Figure 3A showing the bandwidth spread of a classified IRED without a filter as shown in No. 087 and Figure 3B with an unclassified IRED with a narrow bandwidth filter according to the present invention. Shown in comparison with fig.

By using a narrow bandwidth filter according to the present invention, near-infrared interfaces can be The accuracy of the roughtance device is significantly improved. Figure IA shows the "Figure of Value" for a number of devices manufactured according to prior art U.S. Pat.
This is a graphical representation of ``Merit''. "Effectiveness Index" is a measure of the calibration accuracy of the device.

“Value Index” is the range of data (i.e., the highest percent sample value minus the lowest percent sample value)
divided by twice the Rin semi-calibration error. If the "value index" is 3.0 or more, it is statistically advantageous and can be used as a commercial device. A value index of approximately 5 is considered a significant improvement over a value index of 3. FIG. 4B shows "index of value" values for a near-infrared interaftance device made in accordance with the present invention with a narrow bandwidth optical filter between the IRED and the light scattering tube.

A comparison of FIGS. 4A and 4B shows that the use of narrow f-bandwidth optical filters greatly improves the accuracy of the near-infrared interference device.

[Brief explanation of the drawing]

FIG. 1 is a perspective view schematically showing a near-infrared quantitative analyzer to which the present invention can be applied, and FIG. 2 is a perspective view of a near-infrared quantitative analysis device to which the present invention is applied. Further, FIGS. 3A and 3B, which are cross-sectional views schematically showing a narrow-bandwidth optical filter according to the present invention, respectively show the apparatus of FIG. 1 provided with a narrow-bandwidth optical filter according to the present invention. , 4A and 4B are graphs showing the relative energy transfer rates to the sample with and without, respectively, the apparatus of FIG. 1 with a narrow bandwidth optical filter in accordance with the present invention; It is a graph diagram showing the "value index" for those not attached. 10... Device, 12... Tubular member, 16.16'
. 17.17', 18.18' =-IRED, 20°22...Shield, 23...Filter, 28...
Photodetector, 29... window, 30... electrical signal amplifier,
32...reading box, 36...display,
4o... Integral analog-to-digital converter, 41...
Digital processor, S...Test object. Patent applicant Get Scientific Research Institute Co., Ltd.
Hyudrex Incorporated FIG, / FIG, 2 Liquid length (nm) FIG, 3A - i Length (nm) FIG, 3B

Claims (1)

[Claims] 1. A near-infrared quantification device for measuring sample substances containing fat or oil, comprising: (a) means for forming at least one near-infrared point light source; (b) near-infrared rays; (c) an optical filter means with a narrow passband width that filters near-infrared rays of a specific wavelength and passes near-infrared rays with a narrow band width; The point light source means and the filter means are disposed at a first end of the tubular member, and the filter means is provided between the point light source means and the tubular member. interposing the near infrared rays to travel through the filter means and then through the wall of the tubular member and to emit from the point light source means provided at the first end of the tubular member. a tubular member having a length such that the near infrared rays emitted from the tubular member appear substantially uniformly on a second end side of the tubular member, and the second end of the tubular member defines a periphery of a central region; (d) a near-infrared detector arranged to detect near-infrared radiation entering the central region circumscribed by the second end of the tubular member, and generating an electrical signal upon detection of near-infrared radiation; (e) means for preventing near-infrared rays from the wall of the tubular member from directly entering the detector; (f) means for shielding the outside of the tubular member from ambient light; (g) means connected to said detector for amplifying the electrical signal generated by said detector; (h) means connected to said amplifying means for processing the amplified signal and providing a reading representative of the percentage of fat within said sample material; and data processing and reading means capable of performing the following steps. 2. having an electromagnetic interference noise shield with a grounded conductive window substantially transparent to near-infrared energy, said window being located at the second end of said tubular member and shielding from electromagnetic interference noise; The apparatus of claim 1, wherein the detector is shielded. 3. The measuring device according to claim 2, wherein the detector is disposed near the inner second end of the tubular member and adjacent to the window. 4. The point light source has a plurality of pairs of near-infrared light emitting diodes, each diode is arranged approximately symmetrically in the circumferential direction around the tubular member, and a filter is provided between each diode and the tubular member. means are disposed, each of the diodes of each pair being spaced about 180 degrees circumferentially about the tubular member, and the filter means corresponding to each of the diodes of each pair filtering approximately the same wavelength. 2. The measuring device according to claim 1, which allows near-infrared rays to pass through. 5. Optical filter means corresponding to a first pair of said near-infrared light emitting diodes pass near-infrared light having a wavelength of about 930 nanometers to said tubular member, and said optical filter means corresponding to a second pair of said near-infrared light emitting diodes. The optical filter means has a wavelength of about 95
Optical filter means corresponding to the near-infrared light emitting diodes of the other pair are adapted to pass near-infrared rays with a wavelength of about 880 to 890 nanometers to the tubular member. The measuring device according to claim 4. 6. The measuring device according to claim 5, wherein said data processing means is capable of checking whether consecutive readings are within a predetermined tolerance by comparing a plurality of simultaneous readings. 7. The measuring device according to claim 1, wherein the material of the wall of the tubular member is polytetrafluoroethylene or nylon.