JP2005091093A - Microchip for measuring absorbance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microchip for measuring absorbance that is at low cost, can improve measurement precision, and has a strong resistance. <P>SOLUTION: The microchip 2 for measuring absorbance has an optical board 4 for transmitting light. A measurement channel 6 is formed on the optical board 4. The measurement channel 6 has a pair of boundary planes 8, 9 that opposes each other and is nearly in parallel each other. Light enters or is emitted from the measurement channel 6 via the pair of boundary planes 8, 9, and the measurement channel 6 is positioned so that light vertically enters the pair of boundary planes 8, 9 in the measurement channel 6. Further, reflection sections 16, 18 formed on the optical board 4 allow light that enters the measurement channel 6, passes through a specimen liquid in the measurement channel 6, and is emitted from the inside of the measurement channel 6 vertical to the pair of boundary planes 8, 9 to enter the measurement channel 6 vertically to the pair of boundary planes 8, 9 at least once, to pass through the inspection solution in the measurement channel 6, and to be emitted from the inside of the measurement channel 6 vertically to the pair of boundary planes 8, 9 for emitting from the optical board 4 to the outside. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a microchip for measuring absorbance for measuring the absorbance of a small amount of test solution.

  2. Description of the Related Art Conventionally, an absorbance measurement apparatus that uses a sample and a reagent mixed and reacted to form a test solution and measures the absorbance of the test solution to analyze the sample is used. Such an absorbance measurement apparatus is applied to, for example, an in-vitro diagnostic medical device that uses a body fluid such as blood or urine as a sample and performs diagnosis from the analysis result of the sample.

  Patent Document 1 discloses a flow cell for use in an absorbance measurement apparatus. This flow cell has a hollow glass tube in which a suction tube for sucking a test solution is connected to one end. The first and second prisms are attached to the outer surface of the hollow glass tube at positions facing each other.

  When analyzing the sample, the other end of the glass tube is sucked, the test solution is sucked from the tip of the suction tube, and the inside of the glass tube is filled with the test solution. And the light inject | emitted from the light source is made to inject into the test solution in a glass tube. The light incident on the test solution passes through the test solution, then enters the first prism, is folded back by the first prism, and enters the test solution again. The light incident on the test solution again passes through the test solution, enters the second prism, is folded back by the second prism, and is finally emitted from the test solution. The light emitted from the test solution is incident on the optical measuring device and the amount of light is measured.

  The light absorption amount of the test solution can be calculated from the light amount emitted from the light source and the measured light amount. Absorbance can be calculated by dividing this amount of absorbance by the optical path length of the light in the test solution. In the flow cell of Patent Document 1, the light is folded back by the first and second prisms and passed through the test solution three times to increase the optical path length in the test solution, thereby allowing the light and the test solution to interact sufficiently. Therefore, the measurement accuracy of absorbance is improved.

  Absorbance measuring apparatuses are called micro TAS (Total analysis system), Lab-on-chip, etc., and are also developed in microchemical systems that perform chemical processes on a substrate. Patent Documents 2 and 3 disclose a microchip used in such an absorbance measuring apparatus.

  The microchips of Patent Documents 2 and 3 have a glass substrate having a narrow groove formed on one surface. The glass substrate has a scale of several centimeters per side, and the width and depth of the narrow groove are a scale of several hundred μm. A cover member 5 made of a glass plate is bonded to one surface of the glass substrate so as to cover the narrow groove. In this way, a flow path is formed inside the microchip.

  The inner surface of the flow path is subjected to a reflective film treatment at positions facing each other along the longitudinal direction of the flow path. On one end side of the reflective film, an incident portion that is not subjected to the reflective film treatment is formed so that light is incident on the flow path from the outside. Similarly, an emission part is formed on the other end side of the reflection film so that light is emitted from the flow path to the outside.

  When analyzing a sample, a test solution is introduced into an inlet port connected to the flow channel, and the flow channel is filled with the test solution. In this state, the light emitted from the light source is incident on the flow path through the incident portion on one end side of the flow path. The light incident on the flow path passes through the test solution, reaches the reflection film, and is reflected by the reflection film. Then, the light travels in the longitudinal direction of the flow path within the flow path while being subjected to multiple reflections between the reflective films facing each other. Finally, the light reaches the emission part on the other end side of the flow path and is emitted to the outside. The emitted light is incident on an optical measuring device, the amount of light is measured, and the absorbance is calculated.

In the microchips of Patent Documents 2 and 3, light is subjected to multiple reflections by a reflection film and passed through the quarantine many times to increase the optical path length and improve the measurement accuracy of absorbance.
Japanese Utility Model Publication No. 50-6387 Japanese Patent Laid-Open No. 9-218149 JP 2002-221485 A

  In the flow cell of Patent Document 1, it is necessary to accurately arrange the prisms. For this reason, it is necessary to precisely adjust the position of the prism and bond it after the glass tube has been cut flat. Therefore, manufacturing this flow cell requires a great deal of man-hours and precise work, resulting in an increase in cost.

  Further, in the microchips of Patent Documents 2 and 3, it is difficult to obtain an accurate optical path length as described below. When measuring the absorbance, the reagent to be used is different for each inspection item. Since the refractive index of the reagent is different for each reagent, the refractive index of the test solution is different for each inspection item. On the other hand, in order to make multiple reflections of light in the flow path, it is necessary to make light enter the flow path at a predetermined angle that is not perpendicular to the flow path through the incident portion.

  Light that enters the flow path at a predetermined angle with respect to the flow path is refracted at the boundary between the glass plate and the test solution. This refraction angle changes for each inspection item because the refractive index of the test solution is different for each inspection item. As a result, the angle at which the light first enters the reflective film also changes for each inspection item. If the initial angle of incidence on the reflective film is changed, the optical path is changed and the optical path length is changed. As a result, the measurement accuracy of the absorbance obtained by dividing the absorbance by the optical path length is deteriorated. In particular, such a change in the optical path length is accumulated and increased by multiple reflections by the reflection film, so that the measurement accuracy of the absorbance is further deteriorated.

  If the inner surface of the flow path on which the reflective film is formed is a curved surface, the optical path length is further inaccurate. When a light beam having a predetermined spread is reflected by a curved surface, the direction of reflection differs depending on the position of the light beam. As a result, the optical path is changed depending on the position of the light beam in the light beam, and the optical path length is changed. Further, such a change in the optical path length is also accumulated and increased by multiple reflection by the reflection film. As a result, the measurement accuracy of absorbance deteriorates.

  Furthermore, in the microchips of Patent Documents 2 and 3, there is a portion where the reflective film and the test solution are in direct contact. Since the reflective film deteriorates in such a portion, the microchips of Patent Documents 2 and 3 are not suitable for repeated use.

  The present invention has been made by paying attention to the above-mentioned problems, and an object of the present invention is to provide a microchip for measuring absorbance at low cost, with improved measurement accuracy and strong resistance.

The invention of claim 1 is a microchip for absorbance measurement having an optical substrate through which light is transmitted,
A pair of boundary planes formed on the optical substrate, filled with a test solution, facing each other and substantially parallel to each other, and light enters or exits through the pair of boundary planes. A measurement channel positioned so that light is perpendicularly incident on the pair of boundary planes therein;
The light that is formed on the optical substrate, enters the measurement channel, passes through the test solution in the measurement channel, and exits from the measurement channel perpendicular to the pair of boundary planes, is reflected, At least one time incident on the measurement flow path perpendicularly to the pair of boundary planes, allowing the test solution in the measurement flow path to pass, and then exiting from the measurement flow path perpendicularly to the pair of boundary planes, and the optical substrate A reflection part to be emitted from the outside,
The microchip for measuring absorbance is characterized by comprising:

  In the first aspect of the present invention, the measurement flow path and the reflection portion are formed on the optical substrate, the measurement flow path is filled with the test solution, and the light emitted from the light source is applied to the measurement flow path perpendicular to the pair of boundary planes. Incident, passing the test solution in the measurement channel, exiting from the measurement channel perpendicular to the pair of boundary planes, and measuring this light at least once by the reflector perpendicular to the pair of boundary planes The liquid is incident on the flow path, passes the test solution in the measurement flow path, is emitted from the measurement flow path perpendicular to the pair of boundary planes, and is further emitted from the optical substrate to the optical measuring device.

  According to a second aspect of the present invention, the reflecting portion reflects the light emitted from the measurement flow path through the one boundary plane a plurality of times, and is different from a position where the light is emitted. 2. The absorbance measuring microchip according to claim 1, further comprising a prism portion that is incident on the measurement flow path through the same boundary plane at a position.

  In the invention of claim 2, the light emitted from the measurement flow path via the one boundary plane by the prism portion is allowed to pass through the same boundary plane at a position different from the position where the light is emitted. It is made to enter into the measurement channel.

  According to a third aspect of the present invention, the reflecting portion includes a first group of prism portions arranged along one side of the measurement channel along the measurement channel, and one of the first group of prism units. Of the second group disposed along the measurement flow path on the other side of the measurement flow path so as to emit light emitted from one to the other one of the prism portions of the first group. The microchip for measuring absorbance according to claim 2, further comprising the prism portion.

  According to the third aspect of the present invention, the light emitted from one of the first group of prism portions and passing through the test solution in the measurement channel is reflected by the second group of prism portions to be reflected in the measurement channel. By passing the test solution and making it enter another prism of the first group, the test solution in the measurement channel is allowed to pass a plurality of times.

  The invention according to claim 4 is characterized in that the reflection part has a pair of prism parts arranged on both sides of the measurement flow channel so that the light reciprocates between them a plurality of times. Item 2. The microchip for measuring absorbance according to Item 2.

  In the fourth aspect of the present invention, light is reciprocated between a pair of prism portions arranged on both sides of the measurement channel so as to face each other, and the test solution in the measurement channel is allowed to pass a plurality of times. Is.

  The invention according to claim 5 is the absorbance measuring microchip according to any one of claims 1 to 4, wherein the reflecting portion is formed by a space portion formed in the optical substrate.

  In the invention of claim 5, the reflecting portion is formed by the space portion, and the light is totally reflected at the reflecting portion.

  According to a sixth aspect of the present invention, the optical substrate includes a plurality of the measurement flow paths connected in series to each other and a plurality of reflection portions respectively corresponding to the plurality of measurement flow paths. The absorbance measuring microchip according to any one of claims 1 to 5.

  In the sixth aspect of the present invention, the absorbance is measured at a plurality of reflecting portions respectively corresponding to a plurality of measurement flow paths connected in series with each other.

  According to the present invention, it is possible to improve measurement accuracy by using a microchip for measuring absorbance at low cost and strong tolerance.

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1A shows a schematic configuration of an absorbance measurement microchip (hereinafter simply referred to as a microchip) 2 of the present embodiment. As shown in FIG. 1B, the microchip 2 of this embodiment has a plate-like optical substrate 4. The optical substrate 4 is formed of a material that transmits light to such an extent that it does not affect the measurement of absorbance, such as glass or plastic.

  A narrow groove is formed on one surface of the optical substrate 4 by dry etching, mechanical cutting or polishing. A plate-like cover member 5 is joined to one surface of the optical substrate 4 so as to cover the narrow groove. A measurement channel 6 for measuring the absorbance of the test solution is formed by the narrow groove and the cover member 5.

  The cross section in the longitudinal direction of the measurement channel 6 is a fixed rectangle throughout. Both side surfaces of the measurement channel 6 form first and second boundary planes 8 and 9 that face each other. As shown in FIG. 1A, the measurement channel 6 extends linearly in the direction indicated by the arrow A in the figure (hereinafter referred to as the longitudinal direction of the measurement channel). The first and second boundary planes 8 and 9 extend in the longitudinal direction of the measurement channel 6 in parallel with each other.

  At one end of the measurement channel 6, a test solution introduction port 10 for introducing the test solution into the measurement channel 6 is formed. Further, a discharge port 11 for discharging the test solution in the measurement flow path 6 is formed at the other end of the measurement flow path 6.

  On one side of the measurement channel 6, a plurality of triangular prism-shaped space portions 12 a,..., 12 n whose upper and lower surfaces are regular triangles are arranged in parallel on the optical substrate 4 along the longitudinal direction of the measurement channel. These space portions 12a, ..., 12n have the same shape, and the space portions 12a, ..., 12n are referred to as a first group of space portions 12. The space portions 12 a,..., 12 n are formed by processing one surface of the optical substrate 4 in the same manner as the measurement flow path 6. In the present embodiment, the number of the first group of space parts 12 is six, but the number of the first group of space parts 12 may be any number of two or more.

  The axial direction of the triangular prism shape is the depth direction of the measurement channel 6. The upper surface of the triangular prism shape is flush with the upper surface of the measurement channel 6, and the lower surface of the triangular prism shape is flush with the lower surface of the measurement channel 6. The triangular prism-shaped first side surface extends in parallel to the first and second boundary planes 8 and 9 of the measurement flow channel 6. The triangular prism shape is arranged closer to the measurement channel 6 than the first side surface, the second side surface forms an angle of 60 ° with the longitudinal direction of the measurement channel 6, and the third side surface is the measurement channel 6. This is at an angle of 120 ° with the longitudinal direction. The first group of space portions 12 are arranged such that the first side surfaces are slightly separated from each other.

  On the other side of the measurement channel 6, a second group of space portions 14 is formed. The second group of space portions 14 is half the length of one side of the regular triangle on the upper and lower surfaces of the triangular prism after the first group of space portions 12 is moved symmetrically with respect to the longitudinal direction of the measurement channel 6. Thus, the shape is parallel to the longitudinal direction of the measurement channel 6.

  However, one space part at the end in the longitudinal direction is missing in the second group space part 14, and the number of the second group space parts 14 is one more than the number of the first group space parts 12. Only less. When the number of the first group of space portions 12 is two, the second group of space portions 14 is not formed. Moreover, the space part of the both ends of the space part 14 of a 2nd group is the 1st and 2nd half space parts 14a and 14n which lacked the half by the side of an edge part. That is, the upper and lower surfaces of the first and second half space portions 14a and 14n are right triangles. The third side surface of the first half space portion 14a is a plane perpendicular to the longitudinal direction of the measurement channel 6, and is referred to as a first end surface here for convenience. The second side surface of the second half space portion 14n is a plane perpendicular to the longitudinal direction of the measurement channel 6, and is referred to as a second end surface for convenience here.

  By the first group of space portions 12, prism portions 16a, ..., 16n are formed between the space portions. That is, the first reflection surface and the second reflection surface of the prism portion are formed by the first side surface and the second side surface of the adjacent space portions 12a,. These prism portions 16a,... 16n are referred to as a first group of prism portions 16. Similarly, a second group of prism portions 18 are formed by the second group of space portions 14. The light emitted from the measurement channel 6 by the first group of prism portions 16 and the second group of prism portions 18 is at least once in the measurement channel 6 perpendicular to the pair of boundary planes 8 and 9. A reflecting portion is formed that is allowed to enter the measurement channel 6, pass through the test solution in the measurement channel 6, exit from the measurement channel 6 perpendicular to the pair of boundary planes 8 and 9, and exit from the optical substrate 4 to the outside.

  An incident portion 20 into which light is incident from the outside is disposed outside the first end face of the first half space portion 14a. Further, an emission part 22 for emitting light to the outside of the optical substrate 4 is arranged outside the second end face of the second half space part 14n.

  Next, the operation of the microchip 2 of the present embodiment having the above configuration will be described with reference to FIG. When measuring the absorbance of the test solution using the microchip 2, the test solution is introduced into the test solution inlet 10, and the measurement channel 6 is filled with the test solution. In this state, light is incident on the measurement channel 6 in the microchip 2 from the light source 24 as indicated by the arrow B in FIG. 2A and the arrow B ′ in FIG. As the light source 24, laser light such as Ar laser, LED, tungsten lamp or the like is used.

  Here, the light source 24 and the microchip 2 are configured so that the light from the light source 24 passes through the incident portion 20 from the first boundary plane 8 side of the measurement channel to be perpendicular to the first boundary plane 8. It is positioned so as to be incident on the head.

  The light incident on the measurement channel 6 passes through the test solution in the measurement channel 6 and is emitted from the measurement channel 6 perpendicular to the second boundary plane 9. The light emitted from the second boundary plane 9 is incident on the first prism portion 16 a at the end of the first group of prism portions 16. The light incident on the first prism portion 16 a is incident on the first reflecting surface of the first prism portion 16 a at an angle of 45 °, and is all parallel to the longitudinal direction of the measurement channel 6. Reflected. The totally reflected light is incident on the second reflecting surface of the first prism portion 16 a at an angle of 45 ° and is totally reflected perpendicularly to the second boundary plane 9 of the measurement channel 6. The totally reflected light is incident on the measurement channel 6 perpendicular to the second boundary plane 9.

  The light that has passed through the test solution in the measurement channel 6 is emitted from the measurement channel 6 perpendicular to the first boundary plane 8. The emitted light is incident on the second prism portion 18 a located at the end of the second group of prism portions 18. The light incident on the second prism portion 18a travels in the second prism portion 18a in the same manner as the first prism portion 16a and is emitted again to the measurement channel 6.

  In this way, the light is multiple-reflected between the first group of prism portions 16 and the second group of prism portions 18 and travels in the longitudinal direction of the measurement channel 6. The light that has traveled to the prism portion 16n at the longitudinal end of the first group of prism portions 16 passes through the test solution in the measurement channel 6, and then exits from the microchip 2 to the outside via the exit portion 22. Is done. The light emitted to the outside is incident on the light measuring device 25 and the amount of light is measured. As the optical measuring instrument 25, a photoelectric conversion element or the like is used.

  The light absorption amount of the test solution is calculated from the light amount emitted from the light source 24 and the measured light amount. Absorbance is calculated by dividing this absorbance by the optical path length of the light in the test solution. The optical path length D is calculated as D = 2Nd by the width d of the measurement channel (see FIG. 2A) and the number N of the first group of prism portions 16. In this way, the absorbance of the test solution can be measured.

  Therefore, the above configuration has the following effects. When light from the light source 24 is incident on the measurement flow path 6 perpendicular to the first boundary plane 8, multiple reflections occur between the first group of prism portions 16 and the second group of prism portions 18. The light traveling in the longitudinal direction of the measurement flow path 6 is obtained from the optical substrate 4 and the test solution from the shape and arrangement of the first and second boundary planes 8 and 9 and the prism portions 16a, ..., 16n, 18a, ..., 18n. Is always incident perpendicular to the boundary surface. For this reason, when light is emitted from the boundary surface between the optical substrate 4 and the test solution, the light is always emitted perpendicularly to the boundary surface regardless of the refractive index of the test solution. Accordingly, the optical path of light does not change depending on the refractive index of the test solution, and it is possible to always obtain an accurate optical path length. As a result, accurate measurement can be performed.

  Further, the microchip 2 is formed by processing one type of optical substrate 4. For this reason, it is possible to manufacture the microchip 2 at low cost. And only the optical substrate 4 and the cover member 5 forming the boundary surface of the measurement flow path 6 are in contact with the test solution. For this reason, the deterioration of the microchip 2 due to the test solution is prevented, and the resistance of the microchip 2 is improved.

  Further, the first and second reflecting surfaces of the prism portions 16a, ... 16n, 18a, ..., 18n are formed by the space portions 12a, ..., 12n, 14a, ..., 14n formed in the optical substrate 4. . Since light incident on the boundary surface between the optical substrate 4 and the space portion from the optical substrate 4 is totally reflected at the boundary surface, the first and second reflection surfaces of the prism portions 16a,..., 16n, 18a,. It is possible to prevent the amount of light from being reduced in reflection at. Therefore, the amount of light is prevented from decreasing due to causes other than the absorption of the test solution, and the absorbance measurement accuracy is improved.

  FIG. 3 shows a modification of the microchip 2 according to the first embodiment of the present invention. In this microchip, the first and second reflecting surfaces such as the prism portions 30a and 30b are formed by the space portions 28a, ..., 28d having a rectangular parallelepiped shape instead of the triangular prism shape. In addition, the space portion may have any shape that forms the first and second reflection surfaces of the prism portion as described above. For example, the upper surface and the lower surface correspond to the first and second reflection surfaces, and the hypotenuse corresponds to the first and second reflection surfaces. It may be a triangular prism shape which is a right triangle.

  Hereinafter, a second embodiment of the present invention will be described. The microchip of this embodiment differs from the microchip 2 of the first embodiment only in the shape of the prism portion. As shown in FIG. 4, in the microchip of this embodiment, the first prism portion 34 is disposed on one side of the measurement channel. On the other hand, a second prism portion 38 is disposed opposite to the first prism portion 34 on the other side of the measurement channel 6.

  The first prism portion 34 has the same shape as one of the first group of prism portions 16 of the first embodiment. The second prism portion 38 has a shape that is symmetrical to the first prism portion 34 with respect to the longitudinal direction of the measurement flow path 6. However, the first reflecting surface 40a of the second prism portion 38 is translated by a predetermined distance in the longitudinal direction of the measurement flow path 6 and is outside the first reflecting surface 40a of the second prism portion 38. Is formed with an incident portion 42 through which light is incident from the outside. Furthermore, in the part which makes the apex angle of the 2nd prism part 38, it has the shape which notched the 1st reflective surface 40a and the 2nd reflective surface 40b, and the emission part 44 which inject | emits light outside is provided. Is formed.

  Next, the operation of the microchip of the present embodiment having the above configuration will be described. As indicated by an arrow C in FIG. 4, the light that enters the measurement channel 6 from the light source 24, passes through the test solution in the measurement channel 6, and is emitted from the second boundary plane 9 is the first Is incident on the first reflecting point 46a at the outer end of the first reflecting surface 36a of the prism portion 34. The light is incident on the first reflection point 46a at an angle of 45 ° with the first reflection surface 36a, and is totally reflected parallel to the longitudinal direction of the measurement channel 6. Further, the totally reflected light is incident on the second reflection point 46 b at the outer end of the second reflection surface 36 b of the first prism portion 34. The light is incident on the second reflection point 46 b at an angle of 45 ° with the second reflection surface 36 b, totally reflected perpendicularly to the second boundary plane 9 of the measurement channel 6, and reflected on the measurement channel 6. Incident.

  The light that has passed through the test solution in the measurement channel 6 enters the second prism unit 38, travels in the second prism unit 38 in the same manner as the first prism unit 34, and again returns to the first prism. It is injected into the part 34. The light emitted to the first prism portion 34 is incident on the inner side of the first reflection point 46 a of the first reflecting surface of the first prism portion 34.

  In this way, the light travels toward the inside of the first and second prism portions 34 and 38 while performing multiple reflection between the first prism portion 34 and the second prism portion 38. Finally, the light emitted from the first prism portion 34 and passing through the test solution in the measurement channel 6 is reflected by the first and second reflecting surfaces 40a and 40b of the second prism portion 38. Without being emitted, the light is emitted from the emission unit 44 to the photodetector 25.

  Thus, the above configuration has the following effects in addition to the effects of the first embodiment. The first and second reflecting surfaces 36a and 36b of the first prism portion 34 and the first and second reflecting surfaces 40a and 40b of the second prism portion 38 cause multiple reflection of light, and the measurement channel 6 The test solution inside is passed many times. For this reason, only four reflecting surfaces 36a, 36b, 40a, and 40b need be formed on the microchip, and the number of places that require fine processing is reduced. Therefore, it is possible to manufacture the microchip at a lower cost.

  Hereinafter, a third embodiment of the present invention will be described. The microchip of this embodiment is different from the microchip of the first embodiment only in the following configuration. In this microchip, the cover member 5 is formed of the same material as the optical substrate 4. In this microchip, as shown in FIGS. 5A and 5B, an incident space portion 56 and an emission space portion 58 are formed in the incident portion 52 and the emission portion 54, respectively. Yes.

  As shown in FIG. 5A, the incident space 56 is a triangular prism shaped space. The axial direction of the triangular prism shape is the longitudinal direction of the measurement channel 6. The cross section perpendicular to the longitudinal direction of the measurement channel 6 in the incident space is a right triangle whose hypotenuse faces the measurement channel 6. The first side surface of the triangular prism shape forms an angle of 45 ° with the first boundary plane 8 of the measurement channel 6, the second side surface is flush with the bottom surface of the measurement channel, and the third side surface is , Parallel to the first and second boundary planes 8 and 9 of the measurement channel 6. Here, the incident reflection surface of the incident space 56 is formed by the first side surface.

  As shown in FIG. 5 (B), the exit space 58 moves the incident space 56 in the longitudinal direction of the measurement flow channel 6 and then moves around the center line of the first side surface of the triangular prism shape. 1 side surface is rotated by 90 ° while keeping the state where the side surface faces the measurement channel 6. Here, the exit reflecting surface of the exit space 58 is formed by the first side surface.

  Next, the operation of the microchip of the present embodiment having the above configuration will be described. The light source 24 is disposed so as to face one surface of the optical substrate 4. In the light source 24 and the microchip, the light from the light source 24 is reflected by the incident reflection surface, and enters the measurement flow path 6 from the first boundary plane 8 side of the measurement flow path 6 perpendicular to the first boundary plane 8. And is positioned so as to be incident. That is, as indicated by an arrow E in FIG. 5A, the light emitted from the light source 24 passes through the cover member 5 and enters the incident reflection surface. The light is incident on the incident reflection surface at an angle of 45 °, is totally reflected perpendicular to the first boundary plane 8 of the measurement channel, and enters the measurement channel 6.

  Thereafter, the light travels in the longitudinal direction of the measurement flow channel 6 while being subjected to multiple reflections between the first group of prism portions 16 and the second group of prism portions 18 in the same manner as in the first embodiment. Injected into the injection space 58 as indicated by the arrow F in B). The light emitted to the exit space 58 enters the exit reflection surface at an angle of 45 °, and is totally reflected parallel to the first boundary plane 8 of the measurement channel 6. The reflected light is transmitted through the optical substrate 4 and emitted from the optical substrate 4 to the outside. The light emitted to the outside is incident on a light measuring device 25 arranged so as to face the other surface of the optical substrate 4.

  Thus, the above configuration has the following effects in addition to the effects of the first embodiment. An incident reflection surface is formed on the incident portion 52, and an emission reflection surface is formed on the emission portion 54. Light is incident on the optical substrate 4 from the light source 24 arranged to face one surface of the optical substrate 4, and is emitted from the microchip. The light is measured by a light measuring device 25 arranged to face the other surface of the optical substrate 4. For this reason, it is possible to measure the absorbance in each of the plurality of measurement channels by providing a plurality of measurement channels parallel to each other on one microchip.

  In addition, by making the arrangement of the incident space portion 56 and the emission space portion 58 different, it is possible to emit light incident on one surface of the optical substrate 4 from the same surface. It is also possible to emit light incident on the other surface of the optical substrate 4 from the same other surface.

  The fourth embodiment of the present invention will be described below. In the microchip of the first embodiment, the optical substrate 4 is directly processed by mechanical cutting or the like. However, in the microchip of this embodiment, the optical substrate 4 is formed by molding. As a result, the manufacturing cost of the microchip can be further greatly reduced.

  FIG. 6 shows a schematic configuration of a microchip 62 according to a fifth embodiment of the present invention. The microchip 62 is formed with a sample channel 64 and a reagent channel 66 that merge at one place. A sample introduction port 68 for introducing a sample is formed at the end of the sample channel 64, and a reagent introduction port 70 for introducing a reagent is formed at the end of the reagent channel 66. Yes.

  A first measurement channel 74 extends from a junction 72 between the sample channel 64 and the reagent channel 66. The first measurement channel 74 is provided with a first reflecting portion 76 having the same configuration as that of the first embodiment for measuring absorbance. A meandering channel 77 extending in a meandering manner extends from the end of the first measurement channel 74. A second measurement channel 78 extends from the end of the meandering channel 77. The second measuring channel 78 is provided with a second reflecting portion 79 having the same configuration as that of the first embodiment for measuring absorbance. A discharge port 80 is formed at the end of the second measurement channel 78.

  Next, the operation of the microchip 62 of the present embodiment having the above configuration will be described. When measuring the absorbance, the sample is introduced into the sample introduction port 68 and the reagent is introduced into the reagent introduction port 70. Then, the sample and the reagent are moved in the sample channel 64 and the reagent channel 66, respectively, and are guided to the junction 72. The sample and the reagent are mixed at the junction 72 to form a test solution.

  Then, this test solution is moved in the first measurement flow path 74 and guided to the first reflection unit 76, and the absorbance is measured by the first reflection unit 76. Thereafter, the test solution is moved in the meandering channel 77 and guided to the second measurement channel 78. While the test solution is moved in the meandering channel 77, the reaction between the sample and the reagent proceeds. Further, the test solution is moved in the second measurement flow path 78 and guided to the second reflection unit 79, and the second reflection unit 79 measures the absorbance.

  Thus, the above configuration has the following effects in addition to the effects of the first embodiment. The first measurement flow path 74 in which the first reflection section 76 is disposed and the second measurement flow path 78 in which the second reflection section 79 is disposed are connected to each other by a meandering flow path 77. Has been. Then, when moving the test solution from the first measurement channel 74 to the second measurement channel 78, the reaction between the sample and the reagent proceeds in the meandering channel 77. Therefore, by comparing the absorbance measured by the first reflection unit 76 with the absorbance measured by the second reflection unit 78, it is possible to capture the time change of the reaction. That is, in the biochemical examination, there are an endpoint method for measuring the absorbance after the reaction between the reagent and the sample, and a rate method for capturing temporal changes in the reaction, such as calculation of the enzyme activity value. In this embodiment, the rate method is used. It is possible to implement the law.

  In each of the above-described embodiments, the interaction between the light and the test solution increases as the number of times that the test solution passes through the measurement flow path 6 is increased. On the other hand, the optical path length of the test solution does not change due to a change in the refractive index of the test solution, and naturally, the change in the optical path length is accumulated and increased by increasing the number of times the light of the test solution passes through the measurement channel 6. Accordingly, in each of the above-described embodiments, the measurement accuracy of the absorbance is increased as the number of times the test solution passes through the measurement channel 6 is increased. However, improvement in the measurement accuracy of absorbance can be achieved if the light passes through the passage twice or more.

Next, other characteristic technical matters of the present application are appended as follows.
Record
(Additional Item 1) The optical substrate is configured to reflect light incident on the optical substrate in parallel to the pair of boundary planes in a direction perpendicular to the pair of boundary planes, and to enter the flow path; The absorbance measurement micro of any one of claims 1 to 6, further comprising: an emission section that reflects light emitted from the flow path in a direction parallel to the pair of boundary planes and emits the light to the outside. Chip.

  (Additional Item 2) The microchip for measuring absorbance according to any one of Claims 1 to 6 and Additional Item 1, wherein the optical substrate is formed by molding.

The present invention provides an absorbance measurement microchip for measuring the absorbance of a very small amount of a test solution at low cost, with improved measurement accuracy and strong tolerance.

(A) is explanatory drawing which shows schematic structure of the microchip of 1st Embodiment of this invention, (B) is sectional drawing of the microchip of the embodiment. (A) And (B) is explanatory drawing for demonstrating the effect | action of the microchip of 1st Embodiment of this invention. Explanatory drawing which shows a part of modification of the microchip of 1st Embodiment of this invention. Explanatory drawing which shows a part of microchip of 2nd Embodiment of this invention. (A) is sectional drawing which shows the incident part of the microchip of 3rd Embodiment of this invention, (B) is sectional drawing which shows the injection | emission part of the microchip of the same embodiment. Explanatory drawing which shows schematic structure of the microchip of 5th Embodiment of this invention.

Explanation of symbols

2 ... Absorbance measurement microchip, 4 ... Optical substrate, 6 ... Measurement flow path, 8, 9 ... A pair of boundary planes, 16, 18 ... Reflection part.

Claims (6)

A microchip for measuring absorbance having an optical substrate through which light is transmitted,
A pair of boundary planes formed on the optical substrate, filled with a test solution, facing each other and substantially parallel to each other, and light enters or exits through the pair of boundary planes. A measurement channel positioned so that light is perpendicularly incident on the pair of boundary planes therein;
The light that is formed on the optical substrate, enters the measurement channel, passes through the test solution in the measurement channel, and exits from the measurement channel perpendicular to the pair of boundary planes, is reflected, At least one time incident on the measurement flow path perpendicularly to the pair of boundary planes, allowing the test solution in the measurement flow path to pass, and then exiting from the measurement flow path perpendicularly to the pair of boundary planes, and the optical substrate A reflection part to be emitted from the outside,
A microchip for measuring absorbance, comprising: The reflection part reflects the light emitted from the measurement flow path through one of the boundary planes a plurality of times, so that the same boundary plane is at a position different from the position where the light is emitted. The absorbance measurement microchip according to claim 1, further comprising a prism portion that is incident on the measurement channel. The reflection unit is configured to receive light emitted from one of the first group of prism units and the first group of prism units arranged along one side of the measurement channel along the measurement channel. A second group of prism portions arranged along the measurement flow path on the other side of the measurement flow path so as to be emitted to another one of the first group of prism sections; The microchip for measuring absorbance according to claim 2. 3. The absorbance measurement micro of claim 2, wherein the reflection part has a pair of prism parts arranged facing each other on both sides of the measurement flow path so that the light reciprocates between them a plurality of times. Chip. The absorbance measuring microchip according to claim 1, wherein the reflection portion is formed by a space portion formed in the optical substrate. The plurality of measurement flow paths connected in series to each other and a plurality of reflection portions respectively corresponding to the plurality of measurement flow paths are formed on the optical substrate. 5. The microchip for measuring absorbance according to any one of 5 above.

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