JP4175210B2 - Optical measurement method - Google Patents

Description

The present invention relates to an optical measurement method for irradiating an object to be measured while scanning the light, receiving the reflected light, and measuring the characteristics of the object to be measured.

  Conventionally, by immersing a specimen such as urine, blood, or saliva in a test paper, the color state of the test line provided on a part of the test paper is detected, and positive or negative of a specific substance present in the specimen is detected. There are measuring devices that automatically determine. This apparatus detects optical characteristics such as the amount of reflected light on a test line while irradiating a test paper, which is a measurement object, with light and changing the positional relationship between the irradiated light and the test paper (for example, , See Patent Document 1).

  In FIG. 4, the schematic diagram which shows schematic structure of the optical measuring apparatus using a test paper is shown. In FIG. 4A, the main part of the test chip Z is represented by a side view, and FIG. 4B is a top view thereof.

  The light from the light source 1 is formed by the lens 2 and irradiated to the test chip Z in which the test paper 23 is surrounded by the holder 21 and integrated, and the light reflected from the test chip Z is detected by the light receiving element 5. A test paper exposure window 22 is provided in a part of the holder 21 so that the surface of the test paper 23 is exposed.

  At this time, if the specific substance present in the specimen is positive, a color reaction has occurred in the test line 24 on the test paper 23. Therefore, when the irradiation light beam 25 is moved from the position P1 to the position P6, the reflected light amount signal 26 detected by the light receiving element 5 shows a change as shown in FIG. At points Q, R, and S, the amount of reflected light is reduced and signal valleys are generated, which are the test paper exposure window end 22a, the test line 24, and another end of the test paper exposure window, respectively. 22b.

  Here, if the position at which the test line 24 appears is predicted based on the end 22a of the test paper exposure window, a negative determination can be made when the test line does not appear at the predicted position. Further, it is possible to prevent a noise signal generated at a position other than the test line, that is, a similarly generated valley portion from being erroneously detected as a test line. For accurate measurement, a correct detection of the reference point for predicting the position of the test line 24, here, the end 22a of the test paper exposure window is necessary, which is very important.

The end 22a is detected by obtaining a signal intensity difference Vq between a trough Q that first appears after the irradiation light beam 25 starts to move and a subsequent peak, and if this exceeds a specified threshold value, the test is performed. It is recognized as the end 22a of the paper exposure window. The reason for comparing with the threshold value is to eliminate a small valley that appears due to a noise signal. Therefore, a position that is separated from the reference point by a known distance y is predicted as a position where the test line 24 appears. As described above, the test line 24 at the specified position is recognized, and the specific substance existing in the specimen is determined from the coloration state of the test line.
JP 2001-289846 A

  In the above-described conventional configuration, the test paper and the holder are integrated, and the test chip is made disposable for each measurement, and thus there is a problem that the cost for each measurement increases. In order to solve this, without using such a holder, as shown in FIG. 5, by measuring with the test paper placed on a holder that can be reused many times, only the test paper can be measured. It is possible to exchange. In addition, by placing the test paper on the holding table 3, the test paper can be easily handled and the main body of the measuring apparatus is prevented from being contaminated with the specimen.

  FIG. 5A is a diagram showing the side of the holding table, FIG. 5B is a diagram showing the top surface of the holding table, and FIG. 5C shows a signal of the amount of reflected light obtained. In this case, the position reference point is The edge 8a of the test paper 8 can be used to detect whether the difference Vt between the peak and valley signals exceeds the threshold value. Then, using the end 8a as a reference, the characteristics of the test line at a predetermined position are measured therefrom.

  However, there is a new problem in the configuration in which such cost is suppressed. When the irradiation light beam 4 is moved from P1 to P6 and the dirt 28 is present on the surface of the holding table 3, the reflected light amount signal becomes 27. That is, at points T and U, the amount of reflected light is reduced and signal valleys are generated, which correspond to the test paper edge 8a and the stain 28, respectively. Let Vt be the signal intensity difference between the valley T and the following peak, and Vu be the signal difference between the valley U and the following peak. Here, when Vu exceeds a prescribed threshold value, two positions exceeding the threshold value occur, and it becomes difficult to detect the reference point. Further, even when the test paper 8 is forgotten to be mounted on the holding table 3, there is a problem that the measurement operation is performed even though the test paper is not recognized because Vu exists and is erroneously recognized as a reference point. is there.

Therefore, in order to solve the above-described problem, the present invention has a configuration in which a test paper is fixed on a holding table that can be reused many times, and a holding hole is provided in a part of the holding table so that reflected light is not detected. An object of the present invention is to provide an optical measurement method capable of accurately detecting an end portion of a test paper which is an object to be measured and detecting forgetting to attach a test paper even when dirt is attached to a table.

In order to solve the above-described problems, the optical measurement method of the present invention is configured such that a hole is formed in a part of a holding table, and the object to be measured is placed on the holding table so that an end of the object to be measured is located in a part of the hole. The light emitted from the light source is irradiated to the holding table and the object to be measured while changing the relative positional relationship between them, and based on a predetermined change in the amount of reflected light received. In the optical measurement method that recognizes the position of the end of the object to be measured and measures the characteristics of the object to be measured at a position separated from this position, the amount of reflected light when scanning light from the light source The presence of the object to be measured on the holding table is judged by the fact that the period during which the value is below a certain level is shorter than the period when the amount of reflected light is below a certain level when only the holes in the holding table are scanned. It is a feature.

  As described above, according to the present invention, an optical measurement apparatus that accurately recognizes the position of the end of the object to be measured and correctly performs the subsequent measurement operation with the position as a reference can be realized with an inexpensive configuration. Can do. Further, whether or not the object to be measured is attached can be detected, and if it is determined that the object is not attached, erroneous measurement can be avoided by a warning or the like. Furthermore, since it is a structure which can detect the position shift of a to-be-measured object in the middle of a measurement, it becomes possible to avoid an erroneous measurement.

Hereinafter, embodiments of the optical measurement method of the present invention will be described with reference to the drawings.
(Embodiment 1)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 shows an example in which a hole in which reflected light is not detected is provided in a part of the holding table 3. FIG. 1A is a diagram showing the side surface of the holding table, FIG. 1B is a diagram showing the upper surface of the holding table, and FIG. 1C shows a reflected light amount signal obtained by scanning the holding table 3.

In FIG. 1, the holding table 3 is made of a resin member having a rectangular shape, and is configured such that a test paper as a measurement object can be placed on the upper surface. In the optical measuring method , the light from the semiconductor laser (light emitting element) 1 is shaped and irradiated to the holding table 3 by the lens 2, and the reflected light from the holding table 3 is received by the photodiode (light receiving element) 5. In this configuration, the reflected light amount signal is detected.

  The holding base 3 is formed with a hole 6 penetrating at a position slightly deviated from the central portion thereof, so that reflected light is not detected by the photodiode 5 even when light is emitted from the semiconductor laser 1. The size of the hole 6 satisfies the relationship of at least m> 2l and n> l with respect to the diameter l of the irradiation light beam 4 where m is the long side direction of the holding table 3 and n is the short side direction. It is.

  Here, the relative position between the optical system such as the semiconductor laser 1 and the holding table 3 is changed, and the irradiation light beam 4 is scanned from the position P1 to the position P6. At this time, the reflected light amount signal 7 detected by the light receiving element 5 shows a change as shown in FIG. The movement start point P 1 of the irradiation light beam 4 corresponds to the point A 1 of the reflected light amount signal 7. A point P 2 where the irradiation light beam 4 reaches the hole 6 corresponds to a point B 1 of the reflected light amount signal 7. When the irradiation light beam 4 is in the range from P1 to P2, the amount of reflected light indicates V1. The point P3 where the irradiation light beam 4 completely enters the hole 6 corresponds to the point C1 of the reflected light amount signal 7, and the reflected light amount gradually decreases in the range from the irradiation light beam 4 to P3. The point P4 at which the irradiation light beam 4 reaches the holding table 3 corresponds to the point D1 of the reflected light amount signal 7. In the range from the irradiation light beam 4 to P4, the signal is in the ground state because there is no reflected light. Indicates zero. The point P5 at which the irradiation light beam 4 has entered all on the holding table 3 corresponds to the point E1 of the reflected light amount signal 7, and the reflected light amount gradually increases in the range from the irradiation light beam 4 to P5. The movement end point P6 of the irradiation light beam 4 corresponds to the point F1 on the reflected light amount signal 7, and the reflected light amount indicates V1 in the range from the irradiation light beam 4 to P5 to P6.

  Further, the end 6a of the hole 6 corresponds to the point G1 on the reflected light amount signal 7, and the reflected light amount shows a substantially intermediate value (V1 / 2) between the points B1 and C1. Similarly, the other end 6b of the hole 6 corresponds to the point H1 of the reflected light amount signal 7, and the reflected light amount shows a value (V1 / 2) that is substantially intermediate between the point D1 and the point E1.

  FIG. 2 shows a state in which a test paper 8 as a measurement object is placed on the hole 6 of the holding table 3. The test paper 8 is arranged so that the end thereof overlaps the area of the hole 6. 2A is a diagram showing the side surface of the holding table 3, FIG. 2B is a diagram showing the upper surface of the holding table 3, and FIG. 2C shows a reflected light amount signal in this configuration.

The positions P1, P2 ′, P3 ′, P4, P5, and P6 of the irradiation light beam 4 correspond to points A2, B2, C2, D2, E2, and F2 on the reflected light amount signal 9, respectively. Here, P 2 ′ is a position where the irradiation light beam 4 reaches the hole 6 from the surface of the test paper 8, and P 3 ′ is a position where all of the light beam 4 enters the hole 6. In the range where the irradiation light beam 4 is from P1 to P2 ′, the reflected light amount is V2, and in the range from P5 to P6, the reflected light amount is V1.

  Further, the end 8b of the test paper 8 corresponds to the point G2 on the reflected light amount signal 9, and the reflected light amount shows a value (V2 / 2) approximately halfway between the points B2 and C2. Similarly, the end 6b of the hole 6 corresponds to the point H2 on the reflected light amount signal 9, and the reflected light amount shows a value (V1 / 2) that is substantially intermediate between the point D2 and the point E2.

What is very important in the configuration of FIGS. 1 and 2 is that the ground state in which the signal intensity is zero exists in the reflected light amount signals 7 and 9 because the hole 6 is provided. That is, even if the holder 3 is reused, dirt such as a sample may adhere to the surface portion other than the hole 6 of the holder 3, but dirt may adhere to the hole 6. Therefore, the ground state is always detected without being affected by dirt.

  Here, a method for detecting the presence or absence of the test paper 8 using the holes 6 will be described. When the test paper 8 is present, the equivalent width of the ground state, that is, X2 in FIG. 2 is smaller than the equivalent width of the ground state when the test paper 8 is not present, that is, X1 in FIG. Thus, the correct mounting state of the test paper 8 can be recognized.

  That is, if the equivalent width of the actually measured ground state becomes smaller than a predetermined threshold value X3 (X1> X3> X2), it is recognized that the test paper 8 is loaded. Otherwise, it is determined that the test paper 8 is not loaded, and erroneous measurement can be avoided by a warning or the like.

  Of course, the detection of the equivalent width of the ground state is not limited to the distance X2 between the point G2 and the point H2, as explained by the symbols in FIG. 2, but the distance between the point C2 and the point D2, or the point B2 and the point E2. There is no problem even if it is performed at a distance between them or an arbitrary specified point from point B2 to point C2 and an arbitrary specified point distance from point D2 to point E2.

  Further, the position of the end 8b of the test paper 8 can be accurately recognized by detecting the point G2 on the reflected light amount signal 9. By using this position as the reference point of the test paper 8, it is possible to correctly perform the subsequent measurement operation, for example, the measurement of the test line in FIG.

  Further, according to such a configuration, even when the light amount of the irradiation light beam 4 is decreased, the position X2 of the ground state width X2 and the point G2 on the reflected light amount signal 9 does not change. Accordingly, it is possible to determine the presence or absence of the test paper 8 and to detect the position of the end portion 8b of the test paper 8 without being affected by the change in the light amount of the irradiation light beam 4.

(Embodiment 2)
Below, the 2nd Embodiment of this invention is described using FIG. FIG. 3 shows a configuration in which the test paper is overlapped on the hole 6 provided in the holding table 3 as in FIG. In FIG. 3 (a), 8a indicated by a solid line is the initial position of the test paper placed on the holding table 3, and 8b indicated by the broken line is misaligned when the test paper 8 is subsequently subjected to some external impact or the like. It shows the state that has been performed.

  When the test paper position is in the initial state 8a, the reflected light amount signal is 10a, and the equivalent width of the ground state described in the first embodiment is X2, but when the test paper position is shifted to 8c, The reflected light amount signal changes as 10b, and the equivalent value of the ground state width changes as X2 '.

  Accordingly, the point G3 on the reflected light amount signal 10a is detected, the end of the test paper 8a is determined as a reference point, and then an operation such as test line measurement on the test paper 8 is performed, and then the test paper 8 is again processed. By obtaining the position of the end portion of the paper, it is possible to detect whether or not the test paper has been misaligned during the measurement. That is, if the edge position of the test paper obtained again is different from the initially obtained point G3, it is determined that the test paper 8 has shifted, and erroneous measurement in test line measurement or the like can be avoided by a warning or the like. It becomes.

The optical measurement method according to the present invention is an inexpensive configuration in which a measurement object can be placed on a holding table that can be reused many times. It can detect the edge accurately or detect forgetting to attach the object to be measured, and can be applied to the one that uses the test paper as the object to be measured and detects the optical characteristics of samples such as urine, blood, saliva, etc. .

FIG. 3 is a diagram showing a configuration of a holding table and a reflected light amount signal when there is no test paper in the first embodiment of the optical measurement method of the present invention. In the same form, a configuration diagram when a test paper is placed on a holding table, and a diagram showing a reflected light amount signal The block diagram of the optical measuring method in Embodiment 2 of this invention, and the figure which shows a reflected light amount signal Configuration diagram of conventional optical measurement method and diagram showing reflected light amount signal Configuration diagram of another conventional optical measurement method and diagram showing reflected light amount signal

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor laser 2 Lens 3 Holding stand 4 Irradiation light beam 5 Photodiode 6 Hole 7, 9, 10, 11 Reflected light quantity signal 8 Test paper

Claims (1)

A hole is formed in a part of the holding table, the object to be measured is arranged on the holding table so that an end of the object to be measured is located in a part of the hole, and the light emitted from the light source is transmitted to the holding table and the object to be measured. Irradiate the measured object while changing its relative positional relationship, and recognize the position of the end of the object to be measured based on a predetermined change in the amount of reflected light received. In the optical measurement method that measures the characteristics of the object to be measured at positions separated by a distance, only the hole in the holder is scanned during the period when the amount of reflected light when scanning light from the light source is below a certain level. An optical measurement method characterized in that the presence of an object to be measured on a holding table is determined by the fact that the amount of reflected light is shorter than a period during which the amount of reflected light is below a certain level .

Images