JP4486805B2 - Spectroscopic analyzer - Google Patents

Description

  The present invention is a spectroscopic analysis for qualitatively or quantitatively analyzing the absorbance, light transmittance, etc. of various samples by irradiating various samples with light and measuring the spectrum by spectrally analyzing the light transmitted through the samples. More particularly, the present invention relates to a spectroscopic analysis apparatus configured using an optical fiber for light transmission.

  In this type of spectroscopic analysis device, in order to eliminate measurement errors caused by fluctuations in the optical system due to temperature changes in the measurement environment during continuous measurement over a long period of time, in order to perform analysis with high reproducibility and reliability, In addition to the light measurement, it is necessary to periodically measure the light emitted from the light source in the absence of the sample, that is, the reference light.

  As a spectroscopic analyzer for measuring both the sample light and the reference light, conventionally, (1) a so-called double beam system in which light from a light source is divided into two, one light is irradiated onto the sample. The sample light measurement optical path for entering the sample light that has passed through the spectroscopic analysis unit and the reference light measurement optical path for directly entering the other light as the reference light to the spectroscopic analysis unit are configured. Those are known (for example, see Patent Document 1).

  (2) The light source unit, the measurement unit holding the sample, and the apparatus main body including the spectroscopic analysis unit are provided separately, and the light from the light source unit is transmitted to the measurement unit to irradiate the sample. Sample light measurement optical fiber that transmits the sample light that has passed through the spectroscopic analysis unit to be incident thereon, and the reference light measurement that splits the light from the light source unit and directly transmits the reference light to the spectroscopic analysis unit as incident light There is also known an optical fiber type device that uses optical fibers for optical fiber and is configured so that both optical fibers for measurement are branched near the base ends of both optical fibers and light from the light source is simultaneously introduced into the branched fiber or the spectroscopic analyzer. (For example, refer to Patent Document 2).

  (3) The end face of the optical fiber that forms the measurement optical path faces the measurement chamber where the sample can be set, and a reference mirror that reflects the measurement light is attached to the tip of the arm that can rotate about the rotation axis. When a sample is set in the measurement chamber, light emitted from the end face of the optical fiber is transmitted through and reflected by the sample, is incident on the end face of the optical fiber again, and is input to the optical system (spectral analysis unit). When the sample is removed from the measurement chamber and the reference mirror is elastically adhered to the end face of the optical fiber by rotating the arm, the light emitted from the end face of the optical fiber is reflected by the reference mirror. Whether or not the sample is set and the arm is rotated so that the reference light is again incident on the end face of the optical fiber and enters the optical system (spectral analysis unit). The are also known optical fiber type apparatus configured switchable into a reference light measurement state sample light measurement state (e.g., see Patent Document 3).

JP 2001-311662 A US Pat. No. 6,204,919 JP 2001-215191 A

  However, among the above-described conventional spectroscopic analyzers, in the double beam system (1), it is necessary to arrange a condensing lens, a shutter, a concave mirror, and the like in each of the sample light measurement optical path and the reference light measurement optical path. In addition to the large number of optical elements, the overall size of the apparatus is increased, and an increase in equipment cost is inevitable, and light from both optical paths and both optical paths are selectively incident on the spectroscopic analyzer. The difference in the degree of cloudiness and contamination between the two mirrors that make up the cross mirror installed for this purpose adversely affects the ratio of sample light quantity to the reference light quantity, absorbance, etc., and decreases the measurement reproducibility and reliability. was there.

  In addition, the optical fiber type apparatus of (2) requires an optical fiber dedicated for reference light measurement, and it is necessary to branch the optical fiber dedicated for reference light measurement and the optical fiber for sample light measurement. Not only is the structure of the fiber itself complicated, but a special spectroscope must be used, so that there is a problem that the cost of the entire analysis apparatus is higher than that of the double beam method of (1).

  Further, in the optical fiber type apparatus of (3), since the switching between the sample light measurement state and the reference light measurement state is complicated and it is necessary to rely on manual switching, continuous automatic measurement becomes difficult and the measurement efficiency is reduced. In addition to being very bad, the measurement state switching mechanism is provided in the measurement unit, so even if you try to perform quality control such as the concentration of various cleaning solutions in-line in a semiconductor factory, for example, only the measurement unit is on the line. There is a problem that the installation system is difficult to adopt, and therefore, it is unsuitable for use as an in-line type quality control device and has very limited use.

  The present invention has been made in view of the above circumstances, and its purpose is to reduce the number of optical elements and optical fibers to be used, thereby reducing the overall cost and size of the apparatus, and achieving high reproduction accuracy. An object of the present invention is to provide a spectroscopic analyzer that can perform measurement and improve reliability, and that can be easily implemented in-line and can be used for a wider range of applications.

In order to achieve the above object, a spectroscopic analyzer according to the present invention includes a light source, a light focusing means for focusing the light emitted from the light source, an incident slit for allowing the light from the light source to enter, and the incident through the incident slit. The apparatus main body provided with a spectroscopic analysis unit having a detector that splits the light to be separated and detects the light of each of the divided wavelengths is provided separately from the measurement unit that holds the sample. And a first optical fiber for transmitting the light focused by the light focusing means to the measurement unit and irradiating the sample is attached to a position deviating from the light emitting direction of the light source with respect to the apparatus main body, A second optical fiber that transmits the sample light transmitted through the sample and emits the light toward the entrance slit of the spectroscopic analysis unit is attached to the apparatus body, and the focused light by the light focusing means is installed in the apparatus body. The sample light is reflected once and incident on the first optical fiber to irradiate the sample, the sample light is transmitted to the spectroscopic analysis unit through the second optical fiber, and the sample light measurement state is incident, and the first optical fiber of the focused light Measurement light path switching means is provided, which can selectively switch between the reference light measurement state in which the incident light is blocked and the reference light composed of the focused light is reflected once and directly incident on the spectroscopic analysis unit. The means is located at a position away from the rotation axis in an arm that can be rotated around a rotation axis that is located away from the light emission direction of the light source . A single mirror for reflecting the light on the same surface is provided, and the single mirror is rotated by the rotation of the arm, and the first reflecting surface angle at which the focused light is incident on the first optical fiber and the reference light. direct incident of the entrance slit That the second is repositioned freely configured and reflecting surface angle, when said single mirror takes the first reflecting surface angle, the light is focused by the optical focusing means is emitted from the light source is the single After being reflected by one mirror and entering the first optical fiber, passing through the sample and entering the second slit through the entrance slit, and when the single mirror has the second reflecting surface angle, the light source The light emitted from the light and focused by the light focusing means is reflected by the single mirror so as to enter from the entrance slit .

  According to the spectroscopic analysis apparatus according to the present invention having the above-described characteristic configuration, the reference light that directly causes the light from the light source to enter the spectroscopic analysis section simply by switching the measurement optical path switching means provided in the apparatus main body. Since the measurement state can be obtained, the use of many optical elements and optical fibers dedicated to the reference light measurement optical path, as well as special spectrometers for branching the optical fiber, can be omitted, thereby reducing the overall cost and size of the apparatus. Can be planned. Nevertheless, during continuous measurement of sample light over a long period of time, the reference light is measured periodically or irregularly to eliminate measurement errors caused by changes in the optical system due to changes in the sample concentration, etc. over time, and changes in the temperature of the measurement environment. The measurement error factor due to the difference in the degree of haze and contamination of the optical elements in the sample light measurement optical path and the reference light measurement optical path can be greatly reduced. It is possible and the reliability of the apparatus can be remarkably improved. In addition, the measurement unit that holds the sample and the device main body including the light source and the spectroscopic analysis unit are simply connected by the first and second optical fibers, and the two (the measurement unit and the device main body) can be largely separated. Therefore, it is possible to measure various liquid samples by using a flow cell type measurement unit, for example, in-line concentration management, such as placing a measurement unit in the piping section of various cleaning liquids used in semiconductor factories and managing the concentration of the cleaning liquid inline. It is easy to use as a device, and there is an effect that the application range of the device can be expanded.

In the spectroscopic analysis apparatus according to the present invention, since allows to switch the very simple measurement light path configuring means such to modify the reflective surface angle of a single mirror with a rotating arm, the cost of the entire apparatus, downsizing Can be further promoted.

Further, in adopting the measurement optical path switching means of the single mirror system, as described in claim 2 , the arm constituting the measurement optical path switching means is incident on the second optical fiber in the reference light measurement state. From the second optical fiber that forms the sample light measurement optical path when measuring the reference light by being configured to be pivoted to the position that interrupts the optical path from the interrupt second optical fiber to the spectroscopic analysis unit between the slit and the slit It is possible to reliably block the stray light from entering the spectroscopic analysis unit, perform reference light measurement with a high S / N, and further improve the reliability of the apparatus.

Further, in the spectroscopic analysis apparatus according to the present invention, as described in claim 3 , the selective switching operation between the sample light measurement state and the reference light measurement state by the measurement light path switching means is automatically performed based on a preset program. By being configured to be controlled, when measuring sample light continuously over a long period of time, reference light is emitted at an appropriate period corresponding to the type and properties of the sample to be measured, and dark light as necessary. Can be measured regularly and automatically, and the measurement reproducibility can be further improved. Further, by introducing program control to such a measurement state switching operation, it is possible to further increase the effectiveness of the above-described inline type quality control device.
According to a fourth aspect of the present invention, the measurement optical path switching unit reflects the focused light from the light focusing unit to the light source side by the single mirror, and neither the sample light nor the reference light is incident on the spectroscopic analysis unit. It may be possible to switch to the dark light measurement state.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a spectroscopic analyzer D according to a first embodiment of the present invention. The spectroscopic analyzer D is a first light source 1 and a converging unit that condenses light emitted from the light source 1. The incident optical unit 2 having a single condensing lens 3, the incident slit 4 for allowing the light from the light source 1 to enter, and the light incident through the slit 4 are dispersed, and the light of each wavelength separated is detected. The apparatus main body 7 provided with the spectroscopic analysis unit 6 having the multi-channel detector 5 and the measurement unit 11 holding the sample 8 are provided separately from each other, and the spectroscopic analysis apparatus D is provided on the apparatus main body 7 side. And an arithmetic control unit 30 (computer) for calculating the absorbance, light transmittance, and the like based on the operation control and the detection output from the multi-channel detector 5.

  Between the incident optical unit 2 on the apparatus main body 7 side and the measurement unit 11, light emitted from the light source 1 and collected by the first condenser lens 3 is incident and transmitted to the measurement unit 11 to be transmitted to the sample. A first optical fiber 12 for irradiating 8 is installed with both ends thereof attached to fiber holders 13 and 14, and the sample light S transmitted through the sample 8 is transmitted to the incident optical unit 2, and the incident slit 4 is passed through the first optical fiber 12. Then, a second optical fiber 15 for entering the spectroscopic analysis unit 6 is installed with both ends attached to fiber holders 16 and 17.

  The fiber holder 13 for attaching the end of the first optical fiber 12 on the incident optical part 2 side holds a second condenser lens 18 and the fiber holder 14 for attaching the end of the measuring part 11 side. An incident lens 9 for irradiating the sample 8 with the light transmitted through the first optical fiber 12 as a parallel light beam is held, and a fiber holder 16 for attaching the end of the second optical fiber 15 on the measuring unit 11 side is provided. An exit lens 10 for converging the sample light S of the parallel light beam that has passed through the sample 8 to be incident on the end of the fiber 15 is held, and the second light is attached to the fiber holder 17 for attaching the end on the incident optical unit 2 side. A condenser lens 19 for holding the sample light S transmitted through the fiber 15 and forming an image on the entrance slit 4 is held.

  The light source 1 is a continuous spectrum light source made of, for example, a halogen lamp, and a first condenser lens 3 is disposed in the light emission direction.

  The spectroscopic analysis unit 6 is, for example, a Zerni-Turner type, and in addition to the incident slit 4 and the multichannel detector 5, a collimating mirror 20 made of a concave mirror, a diffraction grating 21, and a camera mirror 22 made of a concave mirror. It has.

  Then, in the incident optical unit 2 in the apparatus main body 7, the sample light S is transmitted to the spectroscopic analysis unit 6 through the second optical fiber 15 and incident, and the light from the light source 1 is split as the reference light R. A measurement light path switching means 23 that can be selectively switched between three states of a reference light measurement state that is directly incident on the analysis unit 6 and a dark light measurement state in which neither the sample light S nor the reference light R is incident on the spectroscopic analysis unit 6 Is provided.

  As clearly shown in FIG. 4, the measurement optical path switching means 23 is provided at the tip of an arm 25 that can be driven and rotated in the direction of the arrow around the axis of the rotary shaft 24 via a drive source (not shown) such as a DC motor. 4 is provided with a single reflection mirror 26, and the position of the reflection surface 26a of the reflection mirror 26 is changed to the angles shown in FIGS. 4A, 4B, and 4C by the rotation of the arm 25. Thus, it can be selectively switched between the three states of the sample light measurement state, the reference light measurement state, and the dark light measurement state. The measurement optical path switching means 23 is configured such that when the reflection mirror 26 is switched to the reflection surface angle in the reference light measurement state by the rotation of the arm 25, the arm 25 moves from the second optical fiber 15 to the spectroscopic analysis unit 6. It is comprised so that it may rotate to the attitude | position which interrupts | blocks an optical path. The three-state optical path selection switching operation is configured to be automatically controlled based on a program set and inputted in advance to the arithmetic control unit 30.

Next, the measurement operation of each light by the spectroscopic analyzer D of the first embodiment configured as described above will be described.
During the measurement operation of the sample light S, the reflection mirror 26 is fixed to the reflection surface angle shown in A of FIGS. 1 and 4 by the rotation of the arm 25 in the measurement optical path switching means 23. In this state, the light emitted from the light source 1 passes through the first condenser lens 3, is reflected by the reflecting surface 26a of the reflecting mirror 26, and is condensed by the second condenser lens 18 to be the first light. The light enters the fiber 12. The incident light is transmitted to the measurement unit 11 through the first optical fiber 12 and irradiated to the sample 8 as a parallel light beam through the incident lens 9. The light transmitted through the sample 8, that is, the sample light S is incident on the second optical fiber 15 through the exit lens 10 and transmitted to the incident optical unit 2 of the apparatus body 7 through the second optical fiber 15. The light is condensed by the condenser lens 19 and imaged on the entrance slit 4 of the spectroscopic analysis unit 6.

  The sample light S imaged on the entrance slit 4 becomes a parallel light beam by the collimator mirror 20, enters the diffraction grating 21 at a predetermined angle and is divided for each wavelength, and then faces the camera mirror 22. The light of each wavelength reflected and collected by the camera mirror 22 is detected by the multi-channel detector 5, whereby a sample spectrum I (λ) based on the sample light S is obtained.

During the measurement operation of the reference light R, the reflection mirror 26 is changed and fixed to the reflection surface angle shown in B of FIGS. 2 and 4 by the rotation of the arm 25 in the measurement light path switching means 23. In this state, the light emitted from the light source 1 passes through the first condenser lens 3, is reflected by the reflecting surface 26 a of the reflecting mirror 26, and directly enters the entrance slit 4 of the spectroscopic analysis unit 6 as the reference light R. An image is formed on the entrance slit 4. Then, the reference light R imaged on the entrance slit 4 becomes a parallel light beam by the collimator mirror 20, enters the diffraction grating 21 at a predetermined angle and is divided for each wavelength, and then faces the camera mirror 22. The light of each wavelength reflected and collected by the camera mirror 22 is detected by the multi-channel detector 5, whereby a reference spectrum I _R (λ) based on the reference light R is obtained.

Further, during the measurement operation of dark light, the reflection mirror 26 is changed and fixed to the reflection surface angle shown in C of FIGS. 3 and 4 by the rotation of the arm 25 in the measurement optical path switching means 23. In this state, the light emitted from the light source 1 is not reflected on the light source 1 side by the reflection surface 26a of the reflection mirror 26 and enters the spectroscopic analysis unit 6, but the multi-channel detector 5 and the amplifier (not shown). The dark spectrum I _D (λ) that is unrelated to the optical system is obtained.

  Of the light measurements performed as described above, the sample light S is periodically measured, for example, once every few seconds, and the reference light R is measured, for example, once every 10 minutes. The measurement of dark light is periodically performed, for example, once every hour, and the measurement operation of each light is performed in accordance with the type and properties of the sample 8 and the continuous measurement time. In accordance with the above, each is automatically controlled based on a program preset at an appropriate period.

Then, by inputting the sample spectrum I (λ), the reference spectrum I _R (λ) and the dark spectrum I _D (λ) obtained by each of the above measurements to the calculation control unit 30 and calculating them, The absorbance and light transmittance of the sample in the sample cell 8 are measured and analyzed qualitatively or quantitatively. Hereinafter, a method for measuring the absorbance of the sample using the spectroscopic analyzer D of the present invention will be briefly described. To do.

The absorbance Abs (λ) of the sample is generally expressed by the following formula (1).
Abs (λ) = log ₁₀ {I _O (λ) / I _S (λ)} (1)
Here, I _O (λ) represents the amount of light irradiated to the sample (spectrum), and I _S (λ) represents the sample light spectrum.

In the case of the present invention, the reference spectrum I _R (λ) is obtained in a state where no sample exists in the measurement optical path, as shown in FIG.
I _R (λ) = I _O (λ) (2)
From the above formulas (1) and (2),
Abs (λ) = log ₁₀ {I _R (λ) / I _S (λ)} (3)
The following formula is obtained.

When the multi-channel detector 5 as described above is used, the dark current value is generally different for each channel. Also, when different amplifiers are connected for each channel, the offset voltage differs for each amplifier. The absorbance equation for correcting the difference between the dark current value and the offset voltage and canceling the measurement error due to the dark light amount is:
Abs (λ) = log ₁₀ {I _R (i) −I _D (i)} / {I _S (i) −I _D (i)} (4)
It becomes. Here, i is the number of channels of the multi-channel detector 5 and corresponds to each wavelength, and I _D (i) indicates the dark light quantity (spectrum).

In the case where a sample cell is a liquid and has a storage portion in which the sample solution is stored and a window through which light can be transmitted is provided in the storage portion, the above ( 4) The absorbance indicated by the formula includes the absorbance by the sample cell, and the formula for obtaining the absorbance of only the sample is
Abs (i, t) = log ₁₀ [{I _R (i, t) −I _D (i, t)} / {I _S (i, t) −I _D (i, t)}] − log ₁₀ [ _{{I R (i) -I D} (i)} / {I Air (i) -I D (i)} ... (5)
It becomes. In the equation (5), the first term on the right side changes with time as the concentration of the sample changes, and is therefore a parameter for time t. The second term on the right side is a term for correcting light absorption by the sample cell, and is a fixed value. I _Air (i) is the amount of sample light when air is introduced into the accommodating portion of the sample cell.

  By processing the absorbance Abs (λ) or Abs (i, t) obtained as described above by an appropriate data processing technique, the absorbance of the sample and the concentration of the sample solution can be measured.

  Incidentally, in order to prove the effect of the reproduction accuracy obtained by periodically measuring the reference light and the dark light at the time of measuring the absorbance by the spectroscopic analyzer D of the present invention over a long period of time, the present inventor The following tests were conducted. In this test, when irradiated with light having a wavelength of 348.9 nm in the ultraviolet region, an optical filter having an absorbance of about 0.1 Abs is used as a specimen (sample), and the ambient temperature of the spectroscopic analyzer is changed in a range of 19 to 26 ° C. The absorbance of the specimen is measured continuously for 10 hours, and when the reference light and dark light are measured at a rate of once every 10 minutes during the continuous measurement time, and when the reference light and dark light are not measured, respectively. As a result, the results as shown in FIG. 5 were obtained.

  As is clear from the test results shown in FIG. 5, when the reference light and dark light are not measured, the absorbance (Abs) fluctuates in the range of ± 0.001 Abs as the ambient temperature changes, but in 10 minutes. When the reference light and dark light were measured at a single rate, it was found that the absorbance (Abs) hardly fluctuated regardless of the change in the ambient temperature. As a result, in the spectroscopic analyzer D of the present invention in which the system configuration for automatically measuring the reference light and the dark light periodically is adopted, the optical system fluctuates due to changes in the ambient temperature during continuous measurement over a long period of time. Even if this is unavoidable, it was confirmed that the measurement reproducibility accuracy of the absorbance could be maintained satisfactorily.

  By the way, in the spectroscopic analyzer according to the first embodiment of the present invention having the above-described configuration, the reflection surface angle of the reflection mirror 26 is changed by rotating the arm 25 in the measurement optical path switching means 23 provided in the apparatus body 7. Since the reference light measurement state in which the light from the light source 1 is directly incident on the spectroscopic analysis unit 6 can be obtained simply by changing, many optical elements and optical fibers dedicated to the reference light measurement optical path, and further for optical fiber branching It is possible to reduce the cost and size of the entire apparatus by omitting the use of a special spectroscope.

Nevertheless, as shown in the above test results, measurement errors caused by fluctuations in the optical system due to temperature changes in the measurement environment can be reduced even during continuous measurement over a long period of time, and very few optical elements are used. Combined with the fact that measurement error factors due to differences in the degree of fogging, contamination, etc. of the optical element can be greatly reduced, it is possible to maintain very good measurement reproducibility and significantly improve the reliability of the device. it can.

  In addition, the measurement unit 11 that holds the sample 8 and the apparatus main body 7 that includes the light source 1 and the spectroscopic analysis unit 6 are connected only by the first and second optical fibers 12 and 15. Since it can be largely isolated, the measurement unit 11 is made into a flow cell type for measurement of various liquid samples, for example, a measurement unit is arranged in a piping part of various cleaning liquids used in a semiconductor factory, and a halogen lamp is used as the light source 1 It is possible to measure the ultraviolet or near-infrared absorption spectrum and calculate the concentration by using a calibration curve stored in advance in the calculation control unit 30, whereby the concentration management of the cleaning liquid is performed inline. It is easy to use as a concentration management device for the product, and since it is small in size, it can be easily incorporated into various places in the factory and used. It is possible to remarkably expand.

  Further, at the time of measuring the reference light (see FIG. 2), the arm 25 in the measurement optical path switching means 23 is pivoted to a posture that blocks the optical path from the second optical fiber 15 to the spectroscopic analyzer 6. Therefore, it is possible to reliably block the incidence of stray light from the second optical fiber 15 to the spectroscopic analysis unit 6, perform reference light measurement with a high S / N, and further improve the reliability of the apparatus. it can.

6 to 8 are schematic configuration diagrams of a spectroscopic analysis apparatus D according to a reference example of the present invention. The spectroscopic analysis apparatus D according to this reference example is configured to switch a measurement optical path provided in the incident optical unit 2 of the apparatus main body 7. The means 23 ′ is different from the first embodiment in that the configuration described below is adopted, and the other configurations are the same as those in the first embodiment. Therefore, the measurement optical path switching means 23 ′, which is the main part of the apparatus, is used. Only the incident optical section 2 is illustrated, and the same components as those in the first embodiment are denoted by the same reference numerals and detailed description thereof is omitted.

  In two light emission directions having an appropriate angle with respect to each other from the light emission directions from the light source 1, a condenser lens 3A that forms an optical path for sample light and a condensing lens that forms an optical path for reference light with the open / close shutter 27A. 3B and the open / close shutter 27B are arranged in parallel, and the light emitted from the light source 1 and passed through the open / close shutter 27A is held by the fiber holder 13 on the first optical fiber 12 side on the sample light optical path side. A reflecting mirror 28A that reflects the light toward the second condenser lens 18 is fixedly arranged, and a reference reflecting light 29 that is emitted from the light source 1 and passes through the open / close shutter 27B is disposed on the optical path side for the reference light. A reflecting mirror 28B made of a concave mirror that reflects toward the light is fixedly arranged.

  At a substantially intermediate position between the two fixed reflecting mirrors 28A and 28B, there is a rotating member 32 that can be rotated forward and backward around the axis of the rotating shaft 31 via a driving source (not shown) such as a DC motor. The movable reflecting mirror 29 is held by the rotating member 32. By rotating the rotating member 32 forward and backward, the movable reflecting mirror 29 has a reflecting surface 29a having the second optical fiber 15. The sample light measurement state in which the sample light S transmitted through and condensed by the condensing lens 19 is reflected toward the entrance slit 4 of the spectroscopic analysis unit 6, and the reflection surface 29a is reflected by the fixed reflection mirror 28B. The reference light R to be reflected can be selectively switched to a reference light measurement state in which the reference light R is reflected toward the entrance slit 4 of the spectroscopic analysis unit 6.

Next, the measurement operation of each light by the spectroscopic analyzer D of the reference example having the measurement optical path switching means 23 ′ having the above configuration will be briefly described. During the measurement operation of the sample light S, the shutter 27A is opened and the shutter is opened. While 27B is closed, the movable reflecting mirror 29 is in the sample light measurement state posture as shown in FIG. In this state, the light emitted from the light source 1 passes through the condensing lens 3A and the shutter 27A, is reflected by the fixed reflecting mirror 28A, and is condensed by the second condensing lens 18 to the first optical fiber 12. Incident light is transmitted to the measurement unit 11 through the first optical fiber 12 and irradiated on the sample 8. The sample light S transmitted through the sample 8 is incident on the second optical fiber 15 through the output lens 10, transmitted to the incident optical unit 2 of the apparatus body 7 through the second optical fiber 15, and collected by the condenser lens 19. After being illuminated, the light is reflected by the reflecting surface 29 a of the movable reflecting mirror 29 and imaged on the entrance slit 4 of the spectroscopic analysis unit 6. Thereafter, the sample spectrum I (λ) based on the sample light S is obtained by the same spectroscopic and detection operation as in the first embodiment.

In the measurement operation of the reference light R, the shutter 27A is closed and the shutter 27B is opened, while the movable reflection mirror 29 is switched to the reference light measurement state posture as shown in FIG. In this state, the light emitted from the light source 1 passes through the condensing lens 3B and the shutter 27B, is reflected by the fixed reflecting mirror 28B, and is further reflected by the reflecting surface 29a of the movable reflecting mirror 29 to be used as the reference light R. 6 directly enters the entrance slit 4 and forms an image on the entrance slit 4. Thereafter, the reference spectrum I _R (λ) based on the reference light R is obtained by the same spectroscopic and detection operation as in the first embodiment.

Further, during the dark light measurement operation, as shown in FIG. 8, both the shutters 27A and 27B are closed, and the reference light R and the sample light S emitted from the light source 1 are incident on the spectroscopic analysis unit 6. In addition, a dark spectrum I _D (λ) that is unrelated to the optical system is obtained due to noise from the multi-channel detector 5 and the amplifier (not shown).

Among the measurement of each light performed as described above, the measurement of the sample light S is periodically performed, for example, once every few seconds, and the measurement of the reference light R is performed, for example, once every 10 minutes. The measurement of dark light is periodically performed at a frequency of, for example, once every hour, and the sample spectrum I (λ) and the reference spectrum I _R ( λ) and the dark spectrum I _D (λ) are input to the calculation control unit 30 and processed to measure and analyze the absorbance and light transmittance of the sample 8 qualitatively or quantitatively, This is the same as in the case of the first embodiment described above. Naturally, it is desirable to control each light measuring operation fully automatically based on a program set in advance at an appropriate period according to the type and properties of the sample 8, the continuous measurement time, and the like.

By the way, also in the spectroscopic analysis apparatus D of the reference example having the measurement optical path switching means 23 ′ having the configuration shown in FIGS. 6 to 8, measurement reproducibility equivalent to that of the spectroscopic analysis apparatus of the first embodiment, in-line type Although it is possible to exert an excellent effect in terms of applicability to a concentration management device, etc., when using the configuration as shown in the first embodiment as the measurement optical path switching means, By reducing the number of uses, the entire apparatus can be reduced in cost and size, and the measurement state can be easily switched, so that the in-line implementation is further simplified.

In the spectroscopic analyzer of the first embodiment, the applicability when the concentration management of various cleaning liquids used in, for example, a semiconductor factory is performed in an inline type has been described. By arranging so that the light transmittance of each wavelength of the liquid crystal panel is measured, the present invention can be applied to quality control relating to the light transmittance of the liquid crystal panel.

It is a whole schematic block diagram which shows the sample light measurement state by the spectroscopic analyzer which concerns on 1st Example of this invention. It is a schematic block diagram of the principal part which shows the reference light measurement state by the said spectroscopic analyzer. It is a schematic block diagram of the principal part which shows the dark light measurement state by the said spectroscopic analyzer. It is an expanded block diagram of the measurement optical path switching means which is the principal part of the said spectrometer. It is a graph which shows the result of the light absorbency measurement test by the said spectroscopic analyzer. It is a schematic block diagram which shows the principal part when the measurement optical path switching means which is the principal part of the spectroscopic analyzer which concerns on the reference example of this invention exists in a sample light measurement state. It is a schematic block diagram which shows the principal part when the measurement optical path switching means in the said spectral analyzer is in a reference light measurement state. It is a schematic block diagram which shows the principal part when the measurement optical path switching means in the said spectral analyzer is in a dark light measurement state.

1 Light source 3 Condensing lens (Condensing means)
DESCRIPTION OF SYMBOLS 5 Multichannel detector 6 Spectroscopic analysis part 7 Apparatus main body 8 Sample 11 Measuring part 12 1st optical fiber 15 2nd optical fiber 23,23 'Measuring optical path switching means 24 Rotating shaft 25 Arm 26, 29 Reflecting mirror 26a, 29a Reflecting surface S Sample light R Reference light D Spectroscopic analyzer

Claims (4)

Light source and spectrally the light incident through the entrance slit and the incident slit light is incident from the light focusing means for focusing the light emitted the light source from the light source, and the light of each wavelength that the spectral The apparatus main body having a spectroscopic analysis unit having a detector for detecting the light and the measurement unit for holding the sample are provided separately, and the light focused by the light focusing unit is transmitted to the measurement unit The first optical fiber for irradiating the sample is attached to a position deviated from the light emitting direction of the light source with respect to the apparatus main body, and further, the sample light transmitted through the sample is transmitted to the apparatus main body, A second optical fiber that is emitted toward the entrance slit of the spectroscopic analysis unit is attached,
In the apparatus main body, the light focused by the light focusing means is reflected once and incident on the first optical fiber to irradiate the sample, and the sample light is transmitted to the spectroscopic analysis unit through the second optical fiber and incident. Select between the sample light measurement state and the reference light measurement state in which the focused light is blocked from entering the first optical fiber and the reference light composed of the focused light is reflected once and directly incident on the spectroscopic analysis unit. A switchable measuring optical path switching means is provided,
The measurement light path switching means measures the reference light in the sample light measurement state at a position away from the rotation axis in the arm that can be rotated around the rotation axis at a position deviated from the light emission direction of the light source. In the state, a single mirror is provided for reflecting the reference light on the same surface, and the single mirror is rotated by the arm and the angle of the first reflecting surface on which the focused light is incident on the first optical fiber. The reference light is configured to be freely changeable in position to a second reflecting surface angle at which the reference light is directly incident on the incident slit ,
When the single mirror has the first reflecting surface angle, the light emitted from the light source and focused by the light focusing means is reflected by the single mirror and enters the first optical fiber, and then the sample When the single mirror takes the second reflecting surface angle through the second optical fiber through the second optical fiber, the light emitted from the light source and focused by the light focusing means is the single light. A spectroscopic analyzer characterized by being reflected by a mirror and entering from an entrance slit .   The arm constituting the measurement optical path switching means is configured to be rotated to a posture that interrupts the optical path from the second optical fiber to the spectroscopic analysis unit between the second optical fiber and the entrance slit in the reference light measurement state. The spectroscopic analyzer according to claim 1.   The spectroscopic analyzer according to claim 1 or 2, wherein the selection switching operation between the sample light measurement state and the reference light measurement state by the measurement light path switching means is automatically controlled based on a preset program.   The measurement light path switching means can be switched to a dark light measurement state in which the focused light from the light focusing means is reflected by the single mirror to the light source side, and neither the sample light nor the reference light is incident on the spectroscopic analysis unit. Item 4. The spectroscopic analyzer according to any one of Items 1 to 3.

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