JP2007263587A - Probe and device for measuring absorbance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a probe for measuring absorbance capable of largely taking signal intensity as compared with a conventional example even if a measuring target is thin and the absorbance thereof is low because measuring light is transmitted through the measuring target a plurality of times (twice). <P>SOLUTION: The probe is composed of a floodlight projection means for projecting the light from a light source in the direction of the measuring target, a reflection means for reflecting the light, which is transmitted through the measuring target, in the direction of the measuring target and a light detection means for detecting the light transmitted through the measuring target. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an absorbance measurement probe and an absorbance measurement device, and more specifically, a probe portion used for measuring a near infrared absorption spectrum of a transparent solid sample (measurement object) such as a film using a near infrared spectrometer. About.

As shown in FIG. 4, the absorbance measuring apparatus provided with the absorbance measuring probe according to the prior art includes a light source 111 and a light projecting unit 112 connected by an optical fiber 113, and light is irradiated to the measuring object 115 via the collimator lens 114. Is done. The light that has passed through the measurement object 115 is collected on the end face of the light receiving side optical fiber 118 by the collimator lens 117 of the light receiving unit 116 and is input to the light receiver 119 through the optical fiber 118. With this configuration, the near-infrared (approximately 800-2500 cm-1 wavenumber region) absorption spectrum of the measurement target sample can be measured, and by analyzing the absorption peak in the absorption spectrum, the composition of the measurement target (for example, If the sample is a plastic film, its OH number, moisture content, etc.) can be measured.
In some cases, the light source 111 and the light projecting unit 112, and the light receiver 119 and the light receiving unit 116 are integrated without using the optical fibers 113 and 118.

Japanese Unexamined Patent Publication No. 2000-111472 (page 4 to page 5 FIG. 1)

However, in the absorbance measuring apparatus described in the prior art, the optimum sample thickness when measuring the near-infrared absorption spectrum of an organic substance is generally about 1 to 10 mm, but the film sample is thin ( (Several tens to several hundreds of micrometers), the absorption peak is small, and there is a problem that it is easily affected by noise.
In addition, film samples are often very large (for example, several meters in width) in the manufacturing process, so the light projecting unit and the light receiving unit must be installed separately. In this case, it is necessary to adjust the optical axis so that the light emitted from the light projecting unit is accurately incident on the optical fiber of the light receiving unit when the device is installed. However, this operation is very difficult and time-consuming.
In addition, when the relative position between the units is shifted during use, the amount of light reaching the light receiver greatly fluctuates, resulting in an error factor.

Therefore, by transmitting light several times through the sample to be measured, the actual sample thickness is made larger than the actual sample thickness and the signal intensity is increased, and the positional relationship between the upper and lower units A measurement probe that can adjust the optical axis easily and accurately at the time of equipment installation (and when equipment that has been removed for maintenance, etc. is reinstalled) is realized. Having problems that must be solved.

  In order to solve the above problems, the absorbance measurement probe and absorbance measurement device of the present invention are configured as follows.

(1) The absorbance measurement probe includes a light projecting unit that projects light from a light source in the direction of the measurement target, a reflection unit that reflects the light transmitted through the measurement target in the direction of the measurement target, and the light transmitted through the measurement target. Light receiving means for receiving the received light.
(2) The region of the measurement target that transmits the light beam reflected by the reflection unit is a region different from the region of the measurement target that transmits the light beam from the light projecting unit (1) The probe for measuring absorbance according to 1.
(3) The absorbance measuring probe according to (1), wherein the reflecting means is configured by a retroreflective mirror having a property of returning reflected light in parallel with incident light.
(4) The light projecting means and the light receiving means are integrally formed, and the integrally formed light projecting means, the light receiving means, and the reflecting means are adjusted in advance by a jig so that the optical axes coincide with each other. The probe for measuring absorbance according to (1), wherein the probe is arranged at a predetermined measurement position adjusted in accordance with (1).

(5) The absorbance measurement device includes a spectroscope that generates a predetermined light beam, a light projecting unit that projects the light beam from the spectroscope in a measurement target direction, and a light beam that has passed through the measurement target in the measurement target direction. An absorbance measurement probe comprising a reflecting means for reflecting, a light receiving means for receiving a light beam transmitted through the measurement object, and a light receiver for receiving the light beam received by the light receiving means.
(6) The region of the measurement target that transmits the light beam reflected by the reflection unit is a region different from the region of the measurement target that transmits the light beam from the light projecting unit. The absorbance measuring apparatus according to 1.
(7) The absorbance measuring apparatus according to (5), wherein the reflecting means is configured by a retroreflective mirror having a property of returning reflected light in parallel with incident light.
(8) The light projecting means and the light receiving means are integrally formed, and the integrally formed light projecting means, the light receiving means, and the reflecting means are adjusted in advance by a jig so that the optical axes coincide with each other. The absorbance measurement apparatus according to (5), wherein the absorbance measurement apparatus is arranged at a predetermined measurement location in a state adjusted by the above.

According to this proposal, since the measurement light is transmitted through the measurement object a plurality of times (twice), even when the measurement object is thin and the absorbance is small, the signal intensity can be increased compared to the conventional example. it can.
In addition, the light projecting means and the light receiving means are formed integrally, and the light projecting means and the light receiving means and the reflecting means formed integrally are installed while maintaining the state where the optical axes of the light receiving means and the reflecting means are matched by a jig. Since the positional deviation at the time of installation is eliminated and the jig is used at the time of subsequent adjustment, the re-installation can be performed easily and easily.
In addition, by using a retroreflective mirror that returns reflected light parallel to the incident light as the reflecting means, the angle of the reflected light is not affected by the angle deviation of the reflecting unit after installation, and the measurement is robust. A system can be constructed.

  Next, embodiments of an absorbance measurement probe and an absorbance measurement apparatus according to the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, an absorbance measurement apparatus that includes the absorbance measurement probe of the present invention and that can embody an absorbance measurement method includes a spectroscope 11 that is a light source that generates a predetermined light beam, and a light beam from the spectroscope 11. Is reflected by the reflecting means 14, the reflecting means 14 for reflecting the light beam transmitted through the measuring object 12 in the direction of the same measuring object 12, and the reflecting means 14. The configuration includes an absorbance measurement probe including a light receiving unit 15 that transmits light again through the measurement object 12 and receives the transmitted light, and a light receiver 16 that receives the light received by the light receiving unit 15. Yes.

  Transmission of light from the spectroscope 11 to the light projecting means 13 is performed via an optical fiber 17, and the light projecting means 13 is constituted by a collimator lens 18 and obtained via the optical fiber 17. The light is converted into parallel light and projected in the direction of the measurement object 12.

  Similar to the light projecting means 13, the light receiving means 15 is composed of a collimator lens 19, receives and collects parallel rays from the reflection means 14, and collects the collected rays via an optical fiber 21. Send to.

The reflection means 14 includes a so-called retroreflective mirror 22 that returns reflected light in parallel with incident light, and the retroreflective mirror 22 reflects the incident light in a direction orthogonal to the incident light. A surface 23 and a second reflecting surface 24 that generates outgoing light by reflecting the light in the direction orthogonal to the light beam reflected by the first reflecting surface 23 in a direction opposite to the incident light.
As described above, by using the retroreflective mirror 22, the region of the measurement target 12 that transmits the light beam reflected by the reflection unit 14 is different from the region of the measurement target 12 that transmits the light beam from the light projecting unit 13. It can be an area. The fact that it can be made in different areas means that a single light projection can achieve reciprocal transmission in different areas, so even if the thickness of the measurement object 12 is thin and the absorbance is small, the signal intensity is larger than in the conventional example. Can be taken.
The reflection unit 25 is formed by installing such a retroreflection mirror 22.

  The light projecting means 13 and the light receiving means 15 are integrally formed, and a light projecting unit 26 in which the collimator lens 18 is installed at a constant angle, and a light receiving unit 27 in which the collimator lens 19 is also installed at a constant angle. The light projecting / receiving unit 28 is formed on one base so as to be adjustable.

The reflection unit 25 and the light projecting / receiving unit 28 are adjusted in advance by the optical axis adjustment jig 29 when shipped from the factory, and are projected and received at predetermined measurement locations with the optical axis adjustment jig 29 attached. The unit is fixed by the unit fixing means 31 and the reflection unit fixing means 32.
That is, with the optical axis adjusting jig 29 attached, the light emitting / receiving unit fixing means 31 of the light emitting / receiving unit 28 is attached to the measurement installation location, and the reflection unit fixing means 32 of the reflection unit 25 is attached and fixed to the measurement installation location. The axis adjustment jig 29 may be removed.

  With respect to the absorbance measuring probe constituted by three units of the light projecting / receiving unit 28, the reflecting unit 25, and the optical axis adjusting jig 29, as shown in FIGS. explain.

  The light projecting / receiving unit 28 has a structure in which a light projecting unit 26 and a light receiving unit 27 are arranged in parallel on a unit mounting base 33 formed in a substantially concave rectangular parallelepiped. 27 is fixed on the unit mounting base 33 by an adjusting screw 34 that can be adjusted in the horizontal direction. On the side surface of the unit mounting base 33, a fixed base portion (light emitting / receiving unit fixing means) 35 for fixing at a fixed measurement location is mounted in a standing state. The opposite side surface to which the fixing base 35 is attached is an adjustment surface 36 formed in a square shape, and the adjustment surface 36 has four adjustment screw holes 37 for fixing to the optical axis adjustment jig 29. It has a configuration with.

The reflection unit 25 has a configuration in which a reflection portion 41 including a base 39 is disposed and fixed on a unit mounting base 38 formed in a rectangular parallelepiped having a substantially concave bottom.
The reflecting portion 41 has a configuration in which a retroreflecting mirror (not shown) is provided inside a casing formed in a cylindrical shape, and is configured to be adjusted in the horizontal direction by four adjusting screws 42 provided on the base 39. It has become.
On the side surface of the unit mounting base 38, a fixed base portion (reflecting unit fixing means) 43 for mounting and fixing at a fixed measurement location is mounted in an upright state. The opposite side surface to which the fixed base 43 is attached is an adjustment surface 44 formed in a square shape, and the adjustment surface 44 has four adjustment screw holes 45 for fixing to the optical axis adjustment jig 29. It has a configuration with.

The optical axis adjusting jig 29 is formed in a flat rectangular parallelepiped shape, includes a light projecting / receiving unit adjusting unit 46 for adjusting the light projecting / receiving unit 28 at the upper end, and a reflection unit adjusting unit for adjusting the reflecting unit 25 at the lower end. 47 is provided.
The light projecting / receiving unit adjusting unit 46 is provided by aligning and attaching the adjustment surface 36 of the light projecting / receiving unit 26, and forms a depressed surface 48 that is depressed with respect to the top surface. Provided with a convex portion 51 having a recessed portion left and right for positioning the light projecting / receiving unit 28 in the left-right direction, and a side surface of the convex portion 51 is connected to the left-right positioning portion 52. It becomes the composition which becomes. The recessed surface 48 is provided with position adjustment holes 53 formed symmetrically in two rows.

  The reflection unit adjustment unit 47 is provided by aligning and attaching the adjustment surface 44 of the reflection unit 25. The reflection unit adjustment unit 47 forms a depression surface 53 that is depressed by a predetermined width from a position closer to the inside than the lower end edge. A linear up-and-down positioning part 54 is provided on one end, and a convex part 55 is left at one end, leaving a part of the reflective unit 25 that is recessed in the right-and-left direction. It becomes the composition which becomes. The recessed surface 53 is provided with position adjustment holes 57 formed symmetrically in two rows. Further, two through holes 58 are provided in the upper part of the depressed surface 53 and two through holes 59 are provided in the lower end edge. The through holes 58 and 59 are formed when the reflecting unit 25 connected by the optical axis adjusting jig 29 is fixed to the measurement location such as a building by fixing the reflecting unit fixing means (fixing base) 43 with a screw. 58 and 59 are used for inserting a screwdriver or the like.

The three units of the light projecting / receiving unit 28, the optical axis adjusting jig 29, and the reflecting unit 25 having such a structure are connected at the time of shipment from the factory, and the positional relationship between the light projecting / receiving unit 28 and the reflecting unit 25 is adjusted correctly. .
In connection, first, the adjustment surface 36 of the unit mounting base 33 of the light projecting / receiving unit 28 is brought into contact with the recessed surface 48 of the optical axis adjustment jig 29 (surface-to-surface contact), and the lower end portion of the adjustment surface 36 is vertically positioned 49. In addition, the position of the adjustment surface 36 is adjusted by applying the side of the adjustment surface 36 to the left and right positioning parts 52 of the projection 51 (point application), and the four positions are adjusted while maintaining the state. The adjustment screw 61 can be connected to the jig by passing the adjustment screw 61 through the hole 53 and screwing it into the adjustment screw hole 37.
Similarly, in the reflection unit 25, the adjustment surface 44 of the unit mounting base 38 is applied to the recessed surface 53 of the optical axis adjustment jig 29 (surface-to-surface contact), and the lower end of the adjustment surface 44 is applied to the vertical positioning portion 54 (line). In addition, the side of the adjustment surface 44 is positioned by hitting the left and right positioning portions 56 of the convex portion 55 (point hitting), and the state is maintained and adjusted to the four position adjusting holes 57. It can be connected to the jig by passing the screw 62 and screwing it into the adjusting screw hole 45.

Thus, the light projecting / receiving unit 28 is fixed to the light projecting / receiving unit fixing means (fixed base) while the light projecting / receiving unit 28 with the optical axis adjusted, the optical axis adjusting jig 29, and the reflecting unit 25 remain connected. 35. The reflection unit 25 is fixed using the reflection unit fixing means (fixed base) 43, respectively. Each of the light projecting / receiving unit fixing means and the reflection unit fixing means has a function of fixing each of the light projecting / receiving unit 28 and the reflection unit 25 so that the position of the light emitting / receiving unit fixing means and the reflection unit fixing means are not changed. In addition, it has a function to finely adjust the position and posture to be fixed.
In this state, by removing the optical axis adjustment jig 29, the light projecting / receiving unit 28 and the reflection unit 25 can be separated and fixed in a state where the positional relationship is maintained as it is at the time of shipment from the factory.
Further, the optical axis adjusting jig 29 receives the front surface as a surface, the bottom surface as a line, and the side surface as a point with respect to the mounting surfaces (adjustment surfaces) 36 and 44 of the light projecting / receiving unit 28 and the reflection unit 25. Therefore, by pressing each surface and fixing with screws, it is possible to connect the three units in a state where the same positional relationship as at the time of shipment is reproduced. That is, even if the optical axis is shifted for some reason after the device is installed, and the positional relationship between the units is shifted and the reinstallation becomes necessary, the reinstallation can be easily performed.

Since the measurement light is transmitted through the measurement object a plurality of times (twice), even when the measurement object is thin and the absorbance is small, an absorbance measurement probe that can increase the signal intensity compared to the conventional example is provided. provide.

It is the block diagram which showed schematically the light absorbency measuring apparatus of this invention. It is a three-dimensional view showing the relationship between the absorbance unit, the reflection unit, and the optical axis adjustment jig. It is a three-dimensional view showing a state in which the absorbance unit, the reflection unit, and the optical axis adjustment jig are assembled. It is the block diagram which showed schematically the light absorbency measuring apparatus in a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Spectrometer 12 Measuring object 13 Light projection means 14 Reflection means 15 Light reception means 16 Light receiver 17 Optical fiber 18 Collimator lens 19 Collimator lens 21 Optical fiber 22 Retroreflective mirror 23 1st reflective surface 24 2nd reflective surface 25 Reflective unit 26 Light Emitting Unit 27 Light Receiving Unit 28 Light Emitting / Receiving Unit 29 Optical Axis Adjustment Jig 31 Light Emitting / Receiving Unit Fixing Means 32 Reflecting Unit Fixing Means 33 Unit Mounting Base 34 Adjustment Screw 35 Fixing Base 36 Adjustment Surface 37 Adjustment Screw Hole 38 Unit Mounting Base 39 Base 41 Reflecting portion 42 Adjusting screw 43 Fixed base 44 Adjusting surface 45 Adjusting screw hole 46 Light emitting / receiving unit adjusting portion 47 Reflecting unit adjusting portion 48 Depressed surface 49 Vertical positioning portion 51 Convex portion 52 Left and right positioning portion 53 Depressed surface 54 Vertical positioning portion 55 Convex part 56 Left / right positioning part 57 Position adjustment Hole 58 Through hole 59 Through hole 61 Adjustment screw 62 Adjustment screw

Claims (8)

A light projecting means for projecting light from the light source in the direction of the measurement object;
Reflecting means for reflecting the light beam transmitted through the measurement object in the measurement object direction;
A light receiving means for receiving a light beam transmitted through the measurement object;
An absorbance measurement probe comprising:   The region of the measurement target that transmits the light beam reflected by the reflection unit is a region different from the region of the measurement target that transmits the light beam from the light projecting unit. Absorbance measurement probe.   2. The absorbance measuring probe according to claim 1, wherein the reflecting means is constituted by a retroreflective mirror having a property of returning reflected light in parallel with incident light.   The light projecting means and the light receiving means are integrally formed, and the light projecting means, the light receiving means, and the reflecting means that are integrally formed are adjusted in advance by a jig so that the optical axes coincide with each other, and adjusted by the jig. 2. The probe for measuring absorbance according to claim 1, wherein the probe is arranged at a predetermined measurement location in a state where the probe is in a closed state. A spectroscope for generating a predetermined light beam;
Light projecting means for projecting the light beam from the spectroscope in the direction of the measurement object, reflection means for reflecting the light beam transmitted through the measurement object in the direction of the measurement object, and light receiving means for receiving the light beam transmitted through the measurement object An absorbance measurement probe comprising:
An absorbance measurement apparatus comprising: a light receiver that receives light received by the light receiving means.   The region of the measurement target that transmits the light beam reflected by the reflection unit is a region different from the region of the measurement target that transmits the light beam from the light projecting unit. Absorbance measuring device.   6. The absorbance measuring apparatus according to claim 5, wherein the reflecting means is constituted by a retroreflective mirror having a property of returning reflected light in parallel with incident light. The light projecting means and the light receiving means are integrally formed, and the light projecting means, the light receiving means, and the reflecting means that are integrally formed are adjusted in advance by a jig so that the optical axes coincide with each other, and adjusted by the jig. 6. The absorbance measurement apparatus according to claim 5, wherein the absorbance measurement apparatus is arranged at a predetermined measurement location in a state of being in a closed state.

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