U.S. patent application number 10/181490 was filed with the patent office on 2003-03-13 for test strip measuring method and device.
Invention is credited to Ikegami, Eiji, Inoue, Tomokuni, Mori, Masaaki, Ninomiya, Masao, Tanaka, Akira.
Application Number | 20030049849 10/181490 |
Document ID | / |
Family ID | 18550861 |
Filed Date | 2003-03-13 |
United States Patent
Application |
20030049849 |
Kind Code |
A1 |
Mori, Masaaki ; et
al. |
March 13, 2003 |
Test strip measuring method and device
Abstract
In a test strip measuring method in which a coloration
measurement is conducted while a test strip (4) is being moved,
there are detected the optical characteristics R of the ground of a
test strip and the optical characteristics T of a test line (4b)
which has appeared on the test strip, and the test strip is judged
based on the difference or ratio between R and T. Even though the
ground of the test strip presents variations in optical
characteristics, and even though there are variations among samples
or among test strips, such variations can be absorbed, thus
assuring an accurate judgment.
Inventors: |
Mori, Masaaki;
(Hirakata-shi, JP) ; Ninomiya, Masao;
(Hirakata-shi, JP) ; Inoue, Tomokuni;
(Hirakata-shi, JP) ; Ikegami, Eiji; (Kyoto-shi,
JP) ; Tanaka, Akira; (Hirakata-shi, JP) |
Correspondence
Address: |
FINNEGAN, HENDERSON, FARABOW, GARRETT &
DUNNER LLP
1300 I STREET, NW
WASHINGTON
DC
20006
US
|
Family ID: |
18550861 |
Appl. No.: |
10/181490 |
Filed: |
July 19, 2002 |
PCT Filed: |
January 30, 2001 |
PCT NO: |
PCT/JP01/00606 |
Current U.S.
Class: |
436/46 ;
422/66 |
Current CPC
Class: |
Y10T 436/112499
20150115; Y10T 436/115831 20150115; G01N 21/8483 20130101 |
Class at
Publication: |
436/46 ;
422/66 |
International
Class: |
G01N 035/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 2, 2000 |
JP |
2000-24938 |
Claims
1. A test strip measuring method in which measurement is conducted
while a test strip is being moved, comprising the steps of:
detecting the optical characteristics R of the ground of a test
strip; detecting the optical characteristics T of a test line which
has appeared on said test strip; and conducting a quantitative
measurement or a qualitative judgment on said test strip based on
the difference or ratio between said R and said T.
2. A test strip measuring method according to claim 1, wherein
there is estimated the point of time when said test line will
appear after said test strip has started moving, or the position
where said test line will appear, and a judgment of negativity is
made when said test line did not appear at said estimated point of
time or in said estimated position.
3. A test strip measuring method according to claim 2, wherein the
test strip is held by a test strip holder, said test strip holder
is detected at the time of the start of test strip movement, there
is measured a period of time T1 from said start of test strip
movement to the point of time when the forefront end of said test
strip in the moving direction, has been detected, and there is
estimated, based on said period of time T1, a period of time after
which said test line will appear.
4. A test strip measuring method according to claim 1, wherein to
identify said test line, the difference between the optical
characteristics of a portion which is presumed to be said test
line, and the optical characteristics of the ground of said test
strip, is compared with a threshold value, and said portion is
identified as said test line when said difference is greater than
said threshold value.
5. A test strip measuring method according to claim 1, wherein
there are a plurality of test lines.
6. A test strip measuring method according to claim 1, wherein the
result of said quantitative measurement is converted in terms of
unit with the use of a calibration curve.
7. A test strip measuring method in which measurement is conducted
while a test strip is being moved, comprising the steps of:
detecting the optical characteristics C of a control line which has
appeared on a test strip; detecting the optical characteristics R
of the ground of said test strip; detecting the optical
characteristics T of a test line which has appeared on said test
strip; and conducting a quantitative measurement or a qualitative
judgment on said test strip with use of a determinant and a
reference value, said determinant being served with the difference
or ratio between said R and said T, and said reference value being
served with the difference or ratio between said C and said R.
8. A test strip measuring method according to claim 7, wherein
there is estimated the point of time when said control line will
appear after said test strip has started moving, or the position
where said control line will appear, and it is judged that said
test strip is defective or the inspection is erroneous when said
control line did not appear at said estimated point of time or in
said estimated position.
9. A test strip measuring method according to claim 8, wherein
after said control line has appeared, there is estimated the point
of time when said test line will appear, or the position where said
test line will appear, and a judgment of negativity is made when
said test line did not appear at said estimated point of time or in
said estimated position.
10. A test strip measuring method according to claim 8 wherein said
test strip is held by a test strip holder, said test strip holder
is detected at the time of the start of test strip movement, there
is measured a period of time T1 from said start of test strip
movement to the point of time when the forefront end of said test
strip in the moving direction, has been detected, and there is
estimated, based on said period of time T1, a period of time T2
after which said control line will appear.
11. A test strip measuring method according to claim 10, wherein
after said control line has appeared, there is estimated the point
of time T3 when said test line will appear, and a judgment of
negativity is made when said test line did not appear at said
estimated point of time T3.
12. A test strip measuring method according to claim 7, wherein to
identify said test line, the difference between the optical
characteristics of a portion which is presumed to be said test
line, and the optical characteristics of the ground of said test
strip, is compared with a threshold value, and said portion is
identified as said test line when said difference is greater than
said threshold value.
13. A test strip measuring method according to claim 7, wherein to
identify said control line, the difference between the optical
characteristics of a portion which is presumed to be said control
line, and the optical characteristics of the ground of said test
strip, is compared with a threshold value, and said portion is
identified as said control line when said difference is greater
than said threshold value.
14. A test strip measuring method according to claim 7, wherein
there are a plurality of control lines or a plurality of test
lines.
15. A test strip measuring method according to claim 7, wherein the
result of said quantitative measurement is converted in terms of
unit with the use of a calibration curve.
16. A test strip measuring device in which measurement is conducted
while a test strip is being moved, comprising: a test strip holding
table arranged to be reciprocatingly movable; locking/unlocking
means which is capable of locking said table to the main body of
said test strip measuring device when said table is moved up to the
innermost part, and which is capable of releasing this locked
state; biasing means for resiliently biasing said table in the
direction in which said table springs out from said innermost part;
and resistance giving means for giving resistance to the motion of
said table in the direction in which said table springs out from
said innermost part.
17. A test strip measuring device according to claim 16, wherein
said table is arranged to automatically travel at a uniform
speed.
18. A test strip measuring device according to claim 16, wherein
said locking/unlocking means is arranged to lock said table when
said table is pushed in, and to release this locked state-when said
table is again pushed in.
19. A test strip measuring device according to claim 16, wherein
said table has a rack, and said resistance giving means is arranged
to give a rotational resistance to a gear connected to said
rack.
20. A test strip measuring device according to claim 16, wherein
said table has a rack, and said biasing means is arranged to
rotationally bias a gear connected to said rack.
Description
[0001] This application is based on application Nos. 2000-24938,
2000-24939 and 2000-160646 filed in Japan, the contents of which
are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to test strip measuring method
and device in which measurement is conducted while a test strip is
being moved.
[0004] 2. Description of Related Art
[0005] There is known a test strip measuring method in which a test
strip is immersed in urine, blood, saliva or the like and the
resultant coloration is measured to automatically judge whether the
specimen is positive or negative.
[0006] A. Examples of the test strip measuring method of the type
above-mentioned, include a method of detecting, while a test strip
is being moved, the optical characteristics T (e.g., reflective
intensity) of a test line which has appeared on the test strip.
[0007] However, the optical characteristics of the grounds of
different test strips vary from one another. This involves the
likelihood that with the mere use of the optical characteristics T
of the test line which has appeared on the test strip, no accurate
measurement can be achieved, resulting in erroneous judgment.
[0008] Further, there are instances where test strip measuring
devices are different in test-strip moving speed from one another,
failing to accurately identify a test line.
[0009] In view of the foregoing, it is an object of the present
invention to provide, in a test strip measuring method of measuring
the coloration of a test strip while the same is being moved, a
test strip measuring method capable of achieving an accurate
quantitative measurement or qualitative judgment with variations in
the optical characteristics of the grounds of different test strips
taken into consideration.
[0010] It is a further object of the present invention to provide a
test strip measuring method capable of achieving an accurate
quantitative measurement or qualitative judgment even though test
strip measuring devices are different in test-strip moving speed
from one another.
[0011] B. Examples of the test strip measuring device
above-mentioned include a device arranged to conduct measurement
while a test strip is being moved. As a mechanism for moving the
test strip, there is used a rack pinion mechanism or the like for
changing the rotation of a motor to a linear motion.
[0012] However, the use of a mechanism using a motor causes the
test strip measuring device to be increased in size, weight and
power consumption. Thus, a compact mechanism requiring less power
consumption has been long desired.
[0013] In view of the foregoing, it is another object of the
present invention to provide, in a test strip measuring device for
measuring the coloration of a test strip while the same is being
moved, a test strip measuring device capable of moving a test strip
with a simple arrangement.
SUMMARY OF THE INVENTION
[0014] In this specification, "qualitative judgment" refers to make
a judgment of negativity or positivity, while "quantitative
measurement" refers to obtain a determinant DET in the form of a
numerical value.
[0015] According to the present invention, a test strip measuring
method comprises the steps of: detecting the optical
characteristics R of the ground of a test strip; detecting the
optical characteristics T of a test line which has appeared on the
test strip; and conducting a quantitative measurement or a
qualitative judgment on the test strip based on the difference or
ratio between R and T (claim 1).
[0016] Here, the term of "optical characteristics" refers to
reflective intensity, transmission intensity, fluorescence
intensity and the like.
[0017] According to this method, even though the grounds of
different test strips present variations in optical
characteristics, such variations can be absorbed, thus assuring an
accurate quantitative measurement or qualitative judgment.
[0018] The present invention may be arranged such that there is
estimated the point of time when the test line will appear after
the test strip has started moving, or the position where the test
line will appear, and a judgment of negativity is made when the
test line did not appear at the estimated point of time or in the
estimated position (claim 2). In such an arrangement, it is
possible to prevent a portion which is not actually the test line,
from being erroneously detected as the test line.
[0019] The present invention may be arranged such that there is
measured a period of time T1 from the start of test strip movement
to the point of time when the forefront end of the test strip in
the moving direction, has been detected, and there can be
estimated, based on the period of time T1, a period of time after
which the test line will appear (claim 3). When the period of time
T1 is used as a basis, a period of time after which the test line
will appear, can accurately be estimated even though test strip
holders are different in moving speed from one another.
[0020] To identify the test line, the difference between the
optical characteristics of a portion which is presumed to be the
test line, and the optical characteristics of the ground of the
test strip, can be compared with a threshold value, and the portion
above-mentioned can be identified as the test line when the
difference is greater than the threshold value (claim 4). This
prevents noise from being erroneously judged as the test line.
[0021] According to the present invention, a test strip measuring
method comprises the steps of: detecting the optical
characteristics C of a control line which has appeared on a test
strip; detecting the optical characteristics R of the ground of the
test strip; detecting the optical characteristics T of a test line
which has appeared on the test strip; and conducting a quantitative
measurement or a qualitative judgment on the test strip with use of
a determinant and a reference value. The determinant is based on
the difference or ratio between R and T, and the reference value is
based on the difference or ratio between C and R (claim 7).
[0022] This method is premised on the use of a test strip on which
a control line will appear. According to this method, the
variations in the measuring condition can be absorbed by measuring
the control line, and the variations in optical characteristics of
the grounds of test strips can be absorbed by detecting the optical
characteristics R of the ground of the test strip. This achieves a
more accurate quantitative measurement or qualitative judgment on a
test strip.
[0023] The present invention may be arranged such that there is
estimated the point of time when the control line will appear after
the test strip has started moving, or the position where the
control line will appear, and it is judged that the test strip is
defective or the inspection is erroneous when the control line did
not appear at the estimated point of time or in the estimated
position (claim 8). The present invention may be arranged such that
after the control line has appeared, there is estimated the point
of time when the test line will appear, or the position where the
test line will appear, and a judgment of negativity is made when
the test line did not appear at the estimated point of time or in
the estimated position (claim 9). In each of the arrangements
above-mentioned, it is possible to prevent the control line or the
test line from being erroneously detected.
[0024] The present invention may be arranged such that the test
strip is held by a test strip holder, the test strip holder is
detected at the time of the start of test strip movement, there is
measured a period of time T1 from the start of test strip movement
to the point of time when the forefront end of the test strip in
the moving direction, has been detected, and there is estimated,
based on the period of time T1, a period of time T2 after which the
control line will appear (claim 10). In such an arrangement, the
period of time after which the control line will appear, can
accurately be estimated even though test strip holders are
different in moving speed from one another.
[0025] The present invention may be arranged such that after the
control line has appeared, there is estimated the point of time T3
when the test line will appear, and a judgment of negativity is
made when the test line did not appear at the estimated point of
time T3 (claim 11). In such an arrangement, the period of time
after which the test line will appear, can accurately be estimated
even though test strip holders are different in moving speed from
one another.
[0026] The present invention may be arranged such that to identify
the test line, the difference between the optical characteristics
of a portion which is presumed to be the test line, and the optical
characteristics of the ground of the test strip, is compared with a
threshold value, and the portion above-mentioned is identified as
the test line when the difference is greater than the threshold
value (claim 12), and that to identify the control line, the
difference between the optical characteristics of a portion which
is presumed to be the control line, and the optical characteristics
of the ground of the test strip, is compared with a threshold
value, and the portion above-mentioned is identified as the control
line when the difference is greater than the threshold value (claim
13). In such an arrangement, it is possible to prevent noise from
being erroneously judged as the test line or control line.
[0027] According to the present invention having the arrangement
above-mentioned, the variations in the optical characteristics of
the grounds of test strips can be absorbed, thus achieving an
accurate quantitative measurement or qualitative judgment on each
test strip.
[0028] Even though measuring devices are different in test strip
moving speed from one another, the control line or test line can
securely be identified.
[0029] According to the present invention, a test strip measuring
device comprises: a test strip holding table arranged to be
reciprocatingly movable; locking/unlocking means which is capable
of locking the table to the main body of the test strip measuring
device when the table is moved up to the innermost part, and which
is capable of releasing this locked state; biasing means for
resiliently biasing the table in the direction in which the table
springs out from the innermost part; and resistance giving means
for giving resistance to the motion of the table in the direction
in which the table springs out from the innermost part (claim
16).
[0030] According to the arrangement above-mentioned, when the table
is unlocked and springs out with the test strip held, the table
springs out at a limited speed under the action of the resistance
giving means. Accordingly, even without the use of a motor for
moving the table as conventionally done, the present invention can
achieve, with a simple arrangement, a test-strip movement similar
to that in the prior art.
[0031] The table is arranged to automatically travel at a uniform
speed (claim 17).
[0032] The present invention may be arranged such that the
locking/unlocking means is arranged to lock the table when the
table is pushed in, and to release this locked state when the table
is again pushed in (claim 18). Such an arrangement can start a
coloration measurement on a test strip with a very simple
operation.
[0033] The present invention may be arranged such that the table
has a rack, and the resistance giving means is arranged to give a
rotational resistance to a gear connected to the rack (claim 19).
Such an arrangement can readily give resistance to the table which
presents a linear motion.
[0034] The present invention may be arranged such that the table
has a rack, and the biasing means is arranged to rotationally bias
a gear connected to the rack (claim 20). Such an arrangement can
readily bias the table which presents a linear motion.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] FIG. 1 is a schematic perspective view of a test strip
measuring device of the present invention;
[0036] FIG. 2 is a plan view of the test strip measuring device
with an upper cover 1a and a circuit board secured thereto
removed;
[0037] FIG. 3 is a plan view of the test strip measuring device
with a partition plate 11 removed;
[0038] FIG. 4 is a perspective view of an example in which a
compression coiled spring 14a is used as biasing means for biasing
a test strip holding table 3;
[0039] FIG. 5 is a perspective view illustrating a locking member
3b mounted on the test strip holding table 3;
[0040] FIG. 6A to FIG. 6D are views illustrating the relationship
between the locking member 3b and a pin 13, in which FIG. 6A
illustrates the state where the test strip holding table 3 is being
inserted, FIG. 6B illustrates the engagement position, and each of
FIGS. 6C and 6D illustrates the state where the locked state has
been released;
[0041] FIG. 7 is a plan view illustrating the state where the test
strip holding table 3 is being pushed in to the innermost part such
that the table 3 is locked;
[0042] FIG. 8 is a section view, taken along the line X-X in FIG.
7, illustrating the locked state;
[0043] FIG. 9 is a view illustrating the positions of marks
appeared on a test strip 4;
[0044] FIG. 10 is a graph illustrating the continuous measurement
results (in the case of a positive reaction) of a test strip during
the automatic traveling of the test strip holding table 3;
[0045] FIG. 11A is a graph of typical reflective intensity data,
while FIG. 11B is a graph obtained by differentiating the data in
FIG. 11A;
[0046] FIG. 12 is a graph illustrating the continuous measurement
results (in the case of a negative reaction) of a test strip during
the automatic traveling of the test strip holding table 3;
[0047] FIG. 13 is a graph illustrating the continuous measurement
results of a test strip during the automatic traveling of the test
strip holding table 3 which holds a test strip holder 2;
[0048] FIG. 14 is a graph illustrating the continuous measurement
results of a test strip during the automatic traveling of the test
strip holding table 3 which holds the test strip holder 2;
[0049] FIG. 15 is a flow chart illustrating a test strip measuring
method executed by a microcomputer;
[0050] FIG. 16 is a flow chart (continuation) illustrating a test
strip measuring method executed by the microcomputer; and
[0051] FIG. 17 is a graph illustrating the results obtained through
measurements respectively conducted with the use of the test strip
measuring device of the present invention and another measuring
device of common use.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0052] FIG. 1 is a schematic perspective view of a test strip
measuring device of the present invention. The test strip measuring
device comprises a test strip measuring device main body 1 and a
test strip holder 2 to be changed for each measurement.
[0053] The test strip measuring device main body 1 comprises a test
strip holding table 3 arranged to be reciprocatingly movable, a
display 6 for displaying a measurement result such as positivity,
negativity or the like, and a power switch 5. The test strip
holding table 3 has a concave portion 3a in which a test strip
holder 2 is to be set.
[0054] The test strip holder 2 holds a test strip 4 in a unitary
structure and is to be thrown away after the measurement is
completed.
[0055] FIG. 2 is a plan view of the test strip measuring device
with an upper cover 1a and a circuit board secured thereto
removed.
[0056] The test strip measuring device main body 1 has a partition
plate 11 for defining a space into which the test strip holding
table 3 is introduced. The partition plate 11 has a pin 13 which
project downwardly (to the reverse side of the paper plane of FIG.
2) from the partition plate 11.
[0057] The partition plate 11 has a window 11a through which a test
strip 4 is to be optically measured. The test strip holding table 3
is to be inserted under the partition plate 11.
[0058] FIG. 3 is a plan view with the partition plate 11 removed
(The pin 13 secured to the partition plate 11 is actually not seen,
but is imaginarily illustrated in FIGS. 3 and 7). The rectangular
test strip holding table 3 is so disposed as to be inserted into
the test strip measuring device main body 1, and is provided at one
side thereof with a rack 16. The test strip measuring device main
body 1 has an idle gear 15 to be meshed with the rack 16, and a
drive gear 14 to be meshed with the idle gear 15.
[0059] A viscous damper (not shown) is mounted on the idle gear 15.
For example, the viscous damper is made in the form of an impeller
which is rotatable in association with the idle gear 15 and which
is disposed in a viscous body such as grease.
[0060] The drive gear 14 is resiliently biased to one rotational
direction by a torsion coiled spring. The biasing direction
corresponds to the direction in which the test strip holding table
3 springs out from the test strip measuring device main body 1.
[0061] The biasing means for biasing the test strip holding table 3
is not limited to the drive gear 14 incorporating a torsion coiled
spring. There may be adopted other known means such as a
compression coiled spring 14a for pushing one end of the test strip
holding table 3 as shown in FIG. 4.
[0062] The test strip holding table 3 has a locking member 3b which
locks the test strip holding table 3 with respect to the test strip
measuring device main body 1 when the test strip holding table 3 is
pushed in to the innermost part, and which releases this locked
state by a predetermined operation. Together with the pin 13
mentioned earlier, this locking member 3b forms locking/unlocking
means.
[0063] FIG. 5 is a perspective view illustrating the locking member
3b mounted on the test strip holding table 3. The locking member 3b
is made of a readily sliding resin (ex. nylon), and is so mounted
in a concave portion 3c formed in the test strip holding table 3 as
to be movable in directions A at right angles to the insertion
direction B of the test strip holding table 3. The locking member
3b includes, as shown in FIG. 5, grooves 32, 33 and 34 for
introducing the pin 13, a step portion 35 and a projection 31 for
engaging with the pin 13.
[0064] When the test strip holding table 3 is inserted, a groove 32
of the locking member 3b is moved up to the position of the pin 13.
The groove 32 is gradually raised and then vertically falls down to
communicate with a groove 33. The groove 33 falls down in the
transverse direction to communicate with a lower groove 34. The
groove 34 is raised arcuately as if surrounding a projection 31 and
then vertically falls down to communicate with the groove 32.
[0065] The projection 31 is disposed at that center of the locking
member 3b which is surrounded by the grooves 32, 34. The projection
31 has a concave portion 31a with which the pin 13 is to be
engaged. Disposed under the concave portion 31a is a step portion
35 for introducing the pin 13.
[0066] FIG. 6A to FIG. 6D illustrate the engagement operations of
the locking member 3b with respect to the pin 13. FIG. 6A
illustrates the state where the test strip holding table 3 is being
inserted, FIG. 6B illustrates the engagement position and each of
FIGS. 6C and 6D illustrates the state where the locked state has
been released. The gap between the locking member 3b and the
concave portion 3c is generally designated by 99.
[0067] When the test strip holding table 3 is inserted, the pin 13
is introduced into the groove 32 (FIG. 6A). When the test strip
holding table 3 is further inserted, the pin 13 falls in the groove
33. The boundary between the grooves 32, 33 is inclined in plan
elevation. Accordingly, when the operator's hand is left from the
test strip holding table 3, the locking member 3b receives force in
the upward direction with respect to the paper plane, causing the
locking member 3b to be moved upward. Accordingly, the pin 13 is
fitted, through the step portion 35, to the concave portion 31a of
the locking member 3b (FIG. 6B). This locks the test strip holding
table 3.
[0068] Then, when the test strip holding table 3 is pushed a little
bit, the pin 13 falls down from the step portion 35 to the groove
34. When the operator's hand is left from the test strip holding
table 3, the test strip holding table 3 starts moving because the
table 3 is receiving force in the left direction on the drawing
paper, from the drive gear 14. At this time, the locking member 3b
receives force in the upward direction with respect to the paper
plane and is moved upward because the boundary between the step
portion 35 and the groove 34 is obliquely defined. Accordingly, the
pin 13 is not returned to the concave portion 31a, but falls in the
groove 34 (FIG. 6C).
[0069] When the test strip holding table 3 is further moved, the
pin 13 is raised along the groove 34, then falls in the groove 32
and is then left from the locking member 3b.
[0070] As discussed in the foregoing, the test strip holding table
3 can be locked with respect to the test strip measuring device
main body 1 when the test strip holding table 3 is pushed to the
innermost part, and this locked state can be released when the test
strip holding table 3 is pushed again.
[0071] FIG. 7 is a plan view illustrating the locked state where
the test strip holding table 3 is pushed in to the innermost part.
By the engagement of the pin 13 with the projection 31 of the
locking member 3b, the test strip holding table 3 is locked.
[0072] FIG. 8 is a section view taken along the line X-X of FIG. 7
illustrating the locked state. The upper cover 1a and the circuit
board 23 secured thereto are also illustrated. The pin 13 is placed
on the step portion 35 of the locking member 3b and engaged with
the concave portion 31a.
[0073] As the locking/unlocking releasing means, there may be used
known means other than that shown in FIGS. 6 and 7.
[0074] Disposed on the circuit board 23 are a light projecting
portion 21 having an LED, a light receiving portion 22 having a
photodiode, and a switch 41 for detecting the position of the test
strip holding table 3. A lens 21a is disposed at the tip of the
light projecting portion 21 for adjusting the focus to the surface
of the test strip 4. The light emitting wavelength of the LED is
set to that of light to be absorbed by a mark which will appear on
the test strip 4 (For example, the LED emits green light when the
mark appearing on the test strip 4 is red). The switch 41 has a
rotatable arm 41a. By sensing the position of the arm 41a, the
insertion/removal of the test strip holding table 3 is
detected.
[0075] In the arrangement above-mentioned, when the test strip
holding table 3 is released from the locked state, the test strip
holding table 3 springs out substantially at a uniform rate
(hereinafter referred to as "automatic traveling"), and the switch
41 is actuated. During the automatic traveling, the reflective
intensity of the test strip 4 is measured with the passage of
time.
[0076] The following description will discuss a test strip
measuring method in which a test strip 4 held in the test strip
holding table 3 is continuously measured during the automatic
traveling of the test strip holding table 3.
[0077] <First Test Strip Measuring Method>
[0078] FIG. 9 is a view illustrating the positions of marks which
have appeared on the test strip 4. An arrow D in FIG. 9 shows the
automatic traveling direction of the test strip holding table 3.
Generally, two colored lines of a control line 4a and a test line
4b will appear on the test strip 4. In the present invention, the
control line 4a is used for obtaining a reference value based on
which the reflective intensity of the test line 4b is judged.
[0079] In the following description, the reflective intensity of
the test line 4b, the reflective intensity of the control line 4a
and the reflective intensity of the ground of the test strip 4 are
respectively designated by T, C, R.
[0080] FIG. 10 is a graph illustrating the continuous measurement
results of the test strip 4 during the automatic traveling of the
test strip holding table 3 which holds the test strip holder 2. The
axis of ordinates represents reflective intensity (represented in
voltage in FIG. 10, but the unit is optional), while the axis of
abscissa represents the elapsed time of automatic traveling (in
msec) after the switch 41 has changed from ON to OFF. The larger a
value in the axis of ordinates is, the stronger the reflective
intensity is.
[0081] In this graph, there appear four valleys a, b, c, d, an
intermediate portion e, and a mountain f. The first appearing
valley a represents an edge 36 of the test strip exposing window of
the test strip holder 2. The next appearing valley b represents the
control line 4a, the next valley c represents the test line 4b, and
the next valley d represents an edge 37 of the test strip exposing
window of the test strip holder 2. The mountain f represents an
edge 38 of the test strip exposing window of the test strip holder
2. The portions between the valleys a and b, between the valleys b
and c, and between the valleys c and d, represent the ground
portions of the test strip 4.
[0082] The following description will discuss a test strip
measuring method executed by a microcomputer mounted on the circuit
board 23.
[0083] Based on the data obtained by differentiating the graph of
reflective intensity in FIG. 10, the positions of valleys or
mountains are judged. For example, when a graph of reflective
intensity includes valleys as shown in FIG. 11A, the curve obtained
by differentiating the graph in FIG. 11A is as shown in FIG. 11B.
Accordingly, a zero-cross point from a negative value to a positive
value, is defined as a valley portion, while a zero-cross point
from a positive value to a negative value is defined as a
mountain.
[0084] During the automatic traveling, the difference between the
appearing valley a and the subsequent mountain portion (See V1 in
FIG. 10), is obtained. When this difference exceeds, for the first
time, a first threshold value (for example, 32 mV), the valley a is
regarded as the edge 36 of the test strip exposing window. The
difference is compared with the first threshold value in order to
eliminate small irregularities appearing due to noise.
[0085] The difference between the subsequently appearing valley b
and the subsequent mountain portion (See V2 in FIG. 10) is
obtained. When this difference exceeds a second threshold value
(for example 64 mV), the valley b is regarded as the control line
4a. This difference is compared with the second threshold value in
order to eliminate small irregularities appearing due to noise.
[0086] The difference between the subsequently appearing valley c
and the subsequent mountain portion (See V3 in FIG. 10) is
obtained. When this difference is larger than a third threshold
value (for example 26 mV) and less than a fourth threshold value
(for example 100 mV), the valley c is regarded as the test line 4b.
The difference is compared with the third threshold value in order
to eliminate small irregularities appearing due to noise. The
fourth threshold value is used for detecting the edges 37, 38.
[0087] The foregoing shows the judgment of a positive reaction. In
the case of a negative reaction, the valley c does not appear as
shown in FIG. 12. The microcomputer recognizes the subsequently
appearing valley d as the valley c. When the difference between the
valley d and the mountain f (See V4 in FIG. 12) exceeds the fourth
threshold value, it is regarded that the valley c did not exist,
i.e., the test line 4b was not detected. Thus, there is made a
judgment that the specimen is negative.
[0088] The judgments above-mentioned mean that there have been
identified the valley b based on the control line 4a, the valley c
based on the test line 4b, and the mountain portions.
[0089] Here, the reflective intensity of the control line 4a at the
valley b, the reflective intensity of the test line 4b at the
valley c, and the reflective intensity of the ground of the test
strip 4, are respectively designated by C, T, R. The reflective
intensity R of the ground may be defined as (1) the peak value of
the mountain portion between the valleys b and c, or (2) the center
value or average value of the peak values of the respective
mountain portions.
[0090] The microcomputer obtains a determinant DET according to the
following equation:
DET=(R-T)/(R-C)
[0091] According to this equation, the influence of the ground is
eliminated by obtaining the difference between the reflective
intensity T of the test line 4b and the reflective intensity R of
the ground, and by obtaining the difference between the reflective
intensity C of the control line 4a and the reflective intensity R
of the ground. Further, the influence of the test conditions (for
example, difference among samples, difference among test strips,
etc.) is eliminated by dividing (R-T) of the reflective intensity
of the test line 4b with the influence of the ground eliminated, by
(R-C) of the reflective intensity of the control line 4a with the
influence of the ground eliminated, this (R-C) serving as a
reference value.
[0092] To obtain the determinant DET, the following equation may
also be used:
DET=(R/T)-(R/C)
[0093] According to this equation, the influence of the ground is
eliminated by obtaining the ratio between the reflective intensity
T of the test line 4b and the reflective intensity R of the ground,
and by obtaining the ratio between the reflective intensity C of
the control line 4a and the reflective intensity R of the ground.
Further, the influence of the test conditions is eliminated by
subtracting (R/C) of the reflective intensity of the control line
4a with the influence of the ground eliminated, from (R/T) of the
reflective intensity of the test line 4b with the influence of the
ground eliminated, this (R/C) serving as a reference value.
[0094] The microcomputer stores threshold values T1, T2 for
qualitative judgment (0<T1<T2<1). By comparing the
obtained determinant DET with the threshold values T1, T2, it is
judged that the specimen is negative, quasi-positive, or positive.
More specifically, the specimen is judged as negative when
0<DET<T1, the specimen is judged as quasi-positive when
T1<DET<T2, and the specimen is judged as positive when
T2<DET<1. The threshold values T1, T2 may be determined by
conducting tests on a number of specimens and selecting a value
with which the qualification of patients can be reproduced most
accurately.
[0095] The microcomputer displays, on the display 6, the numerical
value of the determinant DET obtained in the manner
above-mentioned, and the judgment result such as negativity,
quasi-positivity, positivity.
[0096] <Second Test Strip Measuring Method>
[0097] The following description will discuss a second test strip
measuring method improved in identification of a control line or a
test line appearing on a test strip 4.
[0098] According to the first test strip measuring method, a valley
position is identified by comparing the difference in reflective
intensity between valley and mountain, with a threshold value.
[0099] According to the second test strip measuring method,
consideration is taken not only on the reflective intensities of
valley and mountain, but also on the point of time when a valley
appears. This further lowers the rate of erroneous detection of a
valley position, enabling an accurate valley position to be
identified.
[0100] According to the second test strip measuring method, the
edges 36, 37, 38 of the test strip holder 2 are made smooth in
shape such that these edges 36, 37, 38 do not appear in the
measured intensity data. Accordingly, if there is no noise, the
first appearing valley during the test corresponds to the control
line 4a, and the next appearing valley corresponds to the test line
4b.
[0101] Each of FIGS. 13 and 14 is a graph illustrating the
continuous measurement results of a test strip during the automatic
traveling of the test strip holding table 3 which holds a test
strip holder 2. The axis of ordinates represents reflective
intensity (in voltage in FIGS. 13 and 14, but the unit is
optional), while the axis of abscissa represents the elapsed time
of line scan (in msec). FIG. 13 and FIG. 14 are different from each
other in the automatic traveling speed of the test strip holding
table 3 due to the difference in the viscous resistance of the
damper or the difference in the hardness of the coiled spring. Even
though there is difference in automatic traveling speed, the
following processing is the same.
[0102] In each graph, two valleys i, k appear. The first appearing
valley i represents the control line 4a, and the next appearing
valley k represents the test line 4b. A mountain h before the
valley i, and a mountain j between the valleys i, k, represent the
ground portions of the test strip 4.
[0103] FIG. 15 is a flow chart illustrating the second test strip
measuring method executed by a microcomputer.
[0104] At the time when the switch 41 is changed from ON to OFF
(measurement starting point of time), time counting starts (Steps
S1, S2). When the forefront end of the test strip in the moving
direction, is detected during the automatic traveling of the test
strip holding table 3, the output voltage of the light receiving
portion 22 is increased. At the time when the output-voltage
exceeds a threshold value (3V)(Step S3), a time count value T1 is
registered (Step S4). This time count value T1 represents a
distance L1 between the detection position of the light receiving
portion 22 at the time when the switch 41 is changed from ON to OFF
immediately after the start of automatic traveling of the test
strip holding table 3, and the forefront end of the test strip in
the moving direction.
[0105] Thereafter, time counting starts (Steps S5, S6), and it is
judged whether or not a valley has been detected (Step S7) and
whether or not the detected valley corresponds to noise (Step S8).
This valley judgment may be made by a differentiation method as
discussed in connection with FIG. 11A and FIG. 11B. The judgment of
noise may be made, as discussed earlier, by comparing the
difference between the valley and the subsequently appearing
mountain portion, with the threshold value.
[0106] When there is detected the valley i which is not
corresponding to noise, the time count value t at the time of this
valley detection, is set to T2 (Step S9) and it is judged whether
or not T2 is smaller than k1.multidot.T1 (Step S10).
T2<k1.multidot.T1
[0107] The coefficient k1 is set to a value which is equal to or
slightly larger than the ratio between a distance L2 from the
forefront end of the test strip in the moving direction, to the
control line, and the distance L1 above-mentioned. Accordingly, k1
is a constant having no relation to the automatic traveling speed
of the test strip holding table 3.
[0108] When T2<k1.multidot.T1, the microcomputer regards this
valley i as the control line (Step S11). When
T2.gtoreq.k1.multidot.T1, this means that the control line could
not be detected at the position where the control line must appear.
It is therefore judged that the test strip is defective or the
inspection is erroneous (step S13).
[0109] Further, when no valley is detected within the time limit
(Step S12) or when all the valleys detected correspond to noise, it
is judged that the test strip is defective or the inspection is
erroneous (Step S13). This time limit may be the same as the time
k1.multidot.T1 above-mentioned.
[0110] FIG. 16 is a flow chart (continuation) illustrating the test
strip measuring method executed by the microcomputer.
[0111] Time counting starts (Steps S15, 16), and it is judged
whether or not a valley has been detected (Step S17), and it is
judged whether or not the detected valley corresponds to noise
(Step S18).
[0112] When there is detected a valley which does not correspond to
noise, the time count value t at the time of this valley detection,
is set to T3 (Step S19) and it is judged whether or not T3 is
smaller than k2.multidot.T2 (Step S20).
T3<k2.multidot.T2
[0113] The coefficient k2 is set to a value which is equal to or
slightly larger than the ratio between a distance L3 from the
control line of the test strip 4 to the test line thereof, and the
distance L2 above-mentioned. Accordingly, k2 is also a constant
having no relation to the automatic traveling speed of the test
strip holding table 3.
[0114] The following formula may be used in place of the above
one.
T3<k3(T1+T2)
[0115] The coefficient k3 is set to a value which is equal to or
slightly larger than the ratio between a distance L3 from the
control line of the test strip 4 to the test line thereof, and the
distance (L1+L2) above-mentioned. Accordingly, k3 is also a
constant having no relation to the automatic traveling speed of the
test strip holding table 3.
[0116] When the formula of Step S20 is satisfied, the detected
valley is regarded as the test line (Step S21) and a quantitative
measurement is conducted (Step S22). More specifically, there are
calculated the reflective intensity C of the control line, the
reflective intensity T of the test line, and the reflective
intensity R of the ground of the test strip 4, and the following
determinant DET is obtained:
DET=(R-T)/(R-C)
[0117] The microcomputer supplies this determinant DET.
[0118] Further, as mentioned earlier, the threshold values T1, T2
for qualitative judgment are stored. Then, it is judged that the
specimen is negative, quasi-positive, or positive by comparing the
obtained determinant DET with the threshold values T1, T2.
[0119] The microcomputer displays, on the display 6, the numerical
value of the determinant DET obtained in the manner
above-mentioned, and the judgment result such as negativity,
quasi-positivity, positivity.
[0120] When the formula of Step S20 is not satisfied, this means
that the test line could not be detected at the position where the
test line must appear. It is therefore judged that the specimen is
negative(Step S24).
[0121] Further, when no valley is detected within the time limit
(Step S23) or when all the valleys detected correspond to noise, it
is judged that the specimen is negative (Step 24). This time limit
may be the same as the time k2-T2 or k3 (T1+T2).
[0122] In the processing in FIGS. 15 and 16, the microcomputer
executes time-counting to acquire the moving position of the test
strip. Instead of such time-counting, a sensor may be disposed and
linear graduations may be put on the test strip holding table 3 or
the test strip holder 2, such that the sensor reads such
graduations.
[0123] A numerical value obtained by quantitative measurement can
be converted in terms of unit of common use in this industrial
field. In this connection, a calibration curve is formed by
respectively conducting measurements on same test strips with the
use of the test strip measuring device of the present invention and
with the use of other measuring device of common use. FIG. 17 is a
graph illustrating an example of measurement results. The axis of
abscissa represents the measured values obtained by conducting
measurement with a known measuring device (Densitograph AE-6920
manufactured by ATTO Co., Ltd.) arranged to conduct measurement of
test strip based on image data obtained by a CCD camera, while the
axis of ordinates represents the measured values obtained by
conducting measurement with the test strip measuring device of the
present invention. When the measured values obtained by the test
strip measuring device of the present invention are compared with
the measured values obtained by other measuring device, there is
established a correlation coefficient as high as about 0.981.
[0124] The linear line shown in the graph in FIG. 17, is a
calibration curve prepared with the use of a method of least
squares or the like. When this calibration curve is once obtained,
the measured values obtained with the test strip measuring device
of the present invention, can automatically be displayed as
converted in terms of other unit.
[0125] The foregoing has discussed embodiments of the present
invention. However, the present invention should not be limited to
these embodiments, but a variety of modifications can be made
within the scope of the invention. For example, there can be
conducted a quantitative measurement or qualitative judgment even
on a test strip having a plurality of control lines and/or a
plurality of test lines, by applying the algorism in FIGS. 15 and
16 to each of the lines.
[0126] Further, for a test strip arranged such that no control line
appears thereon, the influence of the ground of the test strip can
be eliminated by obtaining the difference R-T or ratio R/T between
the reflective intensity T of the test line and the reflective
intensity R of the ground of the test strip. In such a case, the
DET is obtained according to the following equation:
DET=R-T or
DET=R/T
[0127] In the embodiments above-mentioned, the reflective intensity
R of the ground is defined as (1) the peak value of the mountain
portion between the valleys b and c, or (2) the center value or
average value of the peak values of the respective mountain
portions. Instead of such procedure, (R1-T) may be used instead of
(R-T), and (R2-C) may be used instead of (R-C) wherein R1 is the
reflective intensity of the ground in the immediate proximity of
the test line 4b, and R2 is the reflective intensity of the ground
in the immediate proximity of the control line 4a. In such a case,
even though a test strip presents an uneven distribution of
reflective intensity, an accurate judgment can be made.
[0128] In each of the test strip measuring methods above-mentioned,
the reflective intensity of a test strip is checked, but
transmission intensity may be checked. Further, when a test strip
emits fluorescence, the fluorescence intensity may be checked.
* * * * *