JP2006184249A - Thermal lens spectroscopic analyzer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal lens spectroscopic analyzer of a portable weight and size capable of conducting a precise analysis. <P>SOLUTION: This thermal lens spectroscopic analyzer comprises the first semiconductor laser beam emitting means 1 constituting a light source for excitation light E, the second semiconductor laser beam emitting means 2 constituting a light source for probe light P, a photoreception means for receiving the probe light P transmitted through a thermal lens to output an electric signal in response to light intensity thereof, a signal processing means for processing the electric signal, and a modulation signal generating means having an interface function together with a function for generating a modulation signal used in common to the first semiconductor laser beam emitting means 1 and the signal processing means. An optical unit including a semiconductor laser beam emitting unit assembled in with the first semiconductor laser beam emitting means 1 and the second semiconductor laser beam emitting means 2, and the photoreception means, is formed into a shape stored in a rectangular parallelepiped having 200mm of longitudinal length, 140mm of lateral length and 85mm of height. <P>COPYRIGHT: (C)2006,JPO&amp;NCIPI

Description

  The present invention relates to a thermal lens spectroscopic analyzer that is suitably used in an analyzer that easily analyzes and detects a trace amount of sample.

  Analyzes for bedside diagnosis (POC (point of care) analysis) that performs measurements necessary for medical diagnosis in the vicinity of patients, and analyzes of hazardous substances in rivers and wastes at rivers and waste disposal sites (POU (point of use) analysis), and analysis and measurement at or near the site where analysis and measurement is required, such as contamination inspection at food cooking, harvesting and import sites The importance of (hereinafter collectively referred to as “POC analysis, etc.”) has attracted attention. In recent years, the development of detection methods and detection apparatuses applied to such POC analysis and the like is being emphasized.

In the detection method and the detection apparatus applied to such POC analysis and the like, it is required that the analysis is performed at a low cost and the apparatus is small. Moreover, in medical diagnosis and environmental analysis, it is generally required that highly sensitive and highly accurate analysis be performed in order to accurately compare with a reference value determined by the country.
As a detection method suitable for such POC analysis or the like, there is a photothermal conversion spectroscopic method in which a substance such as a dye in a solution absorbs light and measures the amount of heat generated in the relaxation process. This photothermal conversion spectroscopic method is known as a highly sensitive concentration measurement method.In particular, the thermal lens spectroscopic method using the refractive index distribution due to the temperature distribution generated by the generated heat is an absorptiometric method for measuring the amount of transmitted light. It is known that the sensitivity is 100 times higher than the method (see Non-Patent Document 1).

JP 2000-356611 A JP 2001-66510 A JP 2002-214175 A JP 2002-365251 A JP 2002-365252 A Manabu Tokeshi et al., J. Lumin. Vol. 83-84, 261-264, 1999

  However, an apparatus using a thermal lens spectroscopic analysis method (thermal lens spectroscopic analysis apparatus) is one in which optical components are arranged on an optical bench (see Patent Document 1) or a modified microscope (see Patent Document 2). Conventionally, most of them are large, and are not suitable for POC analysis. As a miniaturized thermal lens spectroscopic analyzer, the spot size and lens system of the laser beam in the area where the thermal lens is formed for the purpose of miniaturizing the optical part is a rod lens (selfoc lens (trade name) ) (See Patent Documents 3 to 5), but considering the signal processing portion as well, it has not always been possible to realize downsizing of the entire system.

The thermal lens spectroscopic analysis apparatus requires a lock-in amplifier for signal processing together with the optical part. However, this lock-in amplifier is expensive and it is difficult to say that the weight and size are suitable for carrying. In POC analysis such as medical diagnosis and environmental analysis, and on-site measurement, it is strongly required that the entire analyzer including the optical portion and the signal processing portion be portable and heavy, so a conventional thermal lens The spectroscopic analyzer was not suitable for POC analysis or the like.
Therefore, the present invention solves the problems of the conventional thermal lens spectroscopic analysis apparatus as described above, enables high-accuracy analysis, and has a portable weight and size. It is an object to provide an analyzer.

  In order to solve the above problems, the present invention has the following configuration. That is, the thermal lens spectroscopic analysis apparatus according to claim 1 of the present invention is configured to make the probe light enter the thermal lens generated in the sample by the incidence of the excitation light, and based on the change of the probe light by the thermal lens at that time. A thermal lens spectroscopic analyzer for analyzing the sample, the first semiconductor laser light emitting means constituting the light source of the excitation light, the second semiconductor laser light emitting means constituting the light source of the probe light, and the thermal lens A light receiving means for receiving the probe light that has passed through and outputting an electrical signal corresponding to the light intensity; a signal processing means for processing the electrical signal and outputting an analysis result; the first semiconductor laser light emitting means; Modulation signal generating means for generating a modulation signal used in common with the signal processing means.

  The thermal lens spectroscopic analysis apparatus according to claim 2 of the present invention is the thermal lens spectroscopic analysis apparatus according to claim 1, wherein the modulation signal generating means includes the first semiconductor laser light emitting means and the second semiconductor laser. It also has an interface function between the light emitting means, the light receiving means, and the signal processing means. The interface function converts an input analog signal into a digital signal and outputs the digital signal.

  Furthermore, the thermal lens spectroscopic analysis apparatus according to claim 3 of the present invention is the thermal lens spectroscopic analysis apparatus according to claim 1 or 2, wherein the first semiconductor laser light emitting means and the second semiconductor laser light emitting means are The semiconductor laser light emitting unit is provided, and the semiconductor laser light emitting unit has a shape that can be accommodated in a rectangular parallelepiped having a length of 85 mm, a width of 80 mm, and a height of 25 mm.

  Furthermore, the thermal lens spectroscopic analyzer according to claim 4 of the present invention is the thermal lens spectroscopic analyzer according to claim 3, wherein the semiconductor laser light emitting unit, the light receiving means, the first semiconductor laser light emitting means, The optical unit includes an optical unit in which electric parts for controlling the output of the second semiconductor laser light emitting means and a signal processing part for processing an electric signal output from the light receiving means are incorporated, and the optical unit has a length of 200 mm. , 140 mm in width and 85 mm in height and can be stored in a rectangular parallelepiped.

  Furthermore, the thermal lens spectroscopic analyzer according to claim 5 of the present invention is the thermal lens spectroscopic analyzer according to any one of claims 1 to 4, wherein the light receiving means transmits the probe through the thermal lens. A light receiving portion that receives light, and a detection portion that detects the received probe light and outputs an electrical signal corresponding to the light intensity, and the light receiving portion transmits the probe through the thermal lens. An optical fiber that receives light and guides it to the detection unit is provided.

Furthermore, the thermal lens spectroscopic analyzer according to claim 6 of the present invention is the thermal lens spectroscopic analyzer according to claim 5, wherein the optical path changing means for changing the optical path of the probe light is placed in front of the light receiving surface of the optical fiber. It is characterized by having arranged.
Furthermore, the thermal lens spectroscopic analyzer according to claim 7 of the present invention is characterized in that the thermal lens spectroscopic analyzer according to any one of claims 1 to 6 is operable by a battery. .

  The thermal lens spectroscopic analyzer of the present invention can carry out highly accurate analysis, and is portable because it is small and lightweight.

Embodiments of a thermal lens spectroscopic analyzer according to the present invention will be described in detail with reference to the drawings.
The thermal lens spectroscopic analysis apparatus according to the present embodiment includes an optical part that performs thermal lens measurement and a signal processing part that performs thermal lens signal processing. First, the optical part will be described with reference to FIG.

  The optical part of the thermal lens spectroscopic analyzer condenses the first laser light emitting means 1 that is the light source of the excitation light E, the second laser light emitting means 2 that is the light source of the probe light P, and the excitation light E and the probe light P. A condenser lens 5 that stores the sample solution S, an optical fiber 8 that receives the probe light P (corresponding to a light receiving portion that is a constituent of the present invention), and detects the probe light P And a light receiving element 9 (corresponding to a detection unit that is a constituent of the present invention) that outputs an electrical signal corresponding to the light intensity. In addition, it is good also as a structure which provides two condensing lenses and condenses the excitation light E and the probe light P with another condensing lens, respectively.

  In the optical part of such a thermal lens spectroscopic analyzer, the excitation light E is output from the first laser light emitting means 1, the probe light P is output from the second laser light emitting means 2, and the probe light P is reflected by the reflector. 3, and is incident on the beam splitter 4. In the beam splitter 4, the excitation light E and the probe light P are coaxial and guided to the condenser lens 5.

The excitation light E condensed to a small beam diameter by the condenser lens 5 is condensed on the sample solution S, thereby forming a thermal lens (not shown). Then, the probe light P condensed to a small beam diameter by the condenser lens 5 is condensed on the thermal lens, and is diverged or condensed by the thermal lens effect.
The excitation light E and the probe light P that have passed through the sample cell 6 are removed only by the excitation light cut filter 7, and only the probe light P that has passed through the thermal lens is received by the light receiving surface of the optical fiber 8. Then, the probe light P is guided to the light receiving element 9 by the optical fiber 8, and the divergence or concentration is measured.

When the sample cell 6 contains a sample-containing solution (sample solution S) and when the sample-free solution is contained, the measurement is performed, and the electric signal output from the light receiving element 9 is measured. The difference may be a thermal lens signal. Normally, this thermal lens signal is proportional to the degree of the thermal lens, that is, the concentration of the sample solution S.
Here, each part of the optical part of such a thermal lens spectroscopic analyzer will be described. The first semiconductor laser light emitting means 1, the second semiconductor laser light emitting means 2, the reflector 3, the beam splitter 4, and the condenser lens 5 are formed as an integral unit (hereinafter, this unit is referred to as “semiconductor laser light emission”). Referred to as a unit). The shape of the semiconductor laser light emitting unit is not particularly limited, but in order to make the thermal lens spectroscopic analyzer portable, it is a shape that can be accommodated in a rectangular parallelepiped having a length of 85 mm, a width of 80 mm, and a height of 25 mm. It is preferable.

  The type of laser used as the first laser emission means 1 which is the light source of the excitation light E is not particularly limited, and a gas laser, a solid laser or the like can be used without any problem, but a thermal lens spectroscopic analyzer is carried. Semiconductor lasers are desirable because they are possible and inexpensive. However, in the case of using a semiconductor laser, since reflected light from each optical component is incident on the light source of the excitation light E again, it becomes noise due to output change. Therefore, high frequency superposition is applied to the semiconductor laser, or a polarization-dependent beam splitter is used. It is desirable to incorporate an optical isolator in combination with a quarter wave plate. Although not a laser, a light-emitting diode can be used as the light source of the excitation light E as long as sufficient sensitivity can be realized in the thermal lens measurement.

Further, the type of laser used as the second laser emission means 2 that is the light source of the probe light P is not particularly limited, and is the same as that of the first laser emission means 1 as long as the wavelength is different from the excitation light E. The laser can be used. A light emitting diode can also be used as a light source for the probe light P.
Further, the reflecting plate 3 is for guiding the probe light P to the beam splitter 4 and can be used without any problem as long as it has a sufficient reflectance at the wavelength of the probe light P. However, it is desirable that the reflectance is close to 100%.

  Further, the beam splitter 4 is for making the excitation light E and the probe light P coaxial, and has a sufficiently high reflectance with respect to the probe light P and a sufficiently high transmittance with respect to the excitation light E. I just need it. However, it is preferable that the probe light P has a reflectance close to 100% and the excitation light E has a transmittance close to 100%. For example, there are those utilizing the fact that the wavelengths of the excitation light and the probe light are different, and those utilizing the fact that the polarization planes of the excitation light and the probe light are different.

  Further, the condensing lens 5 condenses the excitation light E on the sample solution S accommodated in the sample cell 6 and condenses the probe light P on the thermal lens generated in the sample solution S by the excitation light E. Is. The excitation light E is condensed on the sample solution S to form a thermal lens, and the probe light P transmitted coaxially there is diverged or condensed by the thermal lens effect. Since it is known that the sensitivity of the thermal lens signal generally increases as the beam diameter at the condensing position decreases, it is desirable that the numerical aperture of the condensing lens 5 be large in order to obtain high sensitivity. However, if the numerical aperture is increased to increase the degree of condensing, the distance between the light receiving surface of the optical fiber 8 that receives the probe light P and the sample cell 6 is shortened, so that the shape of the sample cell 6 is limited. Alternatively, a slight change in the distance between the light receiving surface of the optical fiber 8 that receives the probe light P and the sample cell 6 may greatly affect the thermal lens measurement.

  Among the components of the optical part, there are a sample cell 6, an excitation light cut filter 7, an optical fiber 8, and a light receiving element 9 other than the semiconductor laser light emission unit. The semiconductor laser light emission unit, the excitation light cut filter 7, The optical fiber 8 and the light receiving element 9 are attached to a single base to form an integrated unit (hereinafter, this unit is referred to as an “optical unit”). The shape of the optical unit is not particularly limited, but in order to make the thermal lens spectroscopic analyzer portable, it should be a shape that can be accommodated in a rectangular parallelepiped having a length of 200 mm, a width of 140 mm, and a height of 85 mm. preferable.

  The sample cell 6 is for storing the sample solution S to be measured, and is preferably detachable from the optical unit. The material of the sample cell 6 is not particularly limited as long as it is transparent to the excitation light E and the probe light P, but it is desirable that the transmittance of the excitation light E and the probe light P is as high as possible. Examples thereof include resin materials such as polymethyl methacrylate (PMMA), polycarbonate (PC), polystyrene (PS), and cycloolefin resin, and glass. The shape of the sample cell 6 is not particularly limited, but it is preferable that a flat surface exists at a position where the excitation light E and the probe light P are incident and transmitted.

  The excitation light cut filter 7 can be used without any problem as long as the excitation light E can be sufficiently removed, but preferably has an optical density of 5 or more. For example, a color glass filter, an interference filter and the like can be mentioned. In this embodiment, the excitation light cut filter 7 is integrated with the optical fiber 8, but may be a separate body.

  Furthermore, the type of the optical fiber 8 is not particularly limited, and an SI (Step Index) type, a GI (Graded Index) type, or the like can be used. The guided mode may be either single mode or multimode. However, when a tolerance for bending is required, the multimode is preferable because the tolerance is high. The material of the optical fiber 8 is not particularly limited, and any material such as resin or glass can be used without any problem. Considering that the cost can be reduced, a multimode waveguide type plastic optical fiber is most preferable.

  Furthermore, the type of the light receiving element 9 is not particularly limited as long as it has sufficient sensitivity to the probe light P, and examples thereof include a photodiode. Further, if the light receiving element 9 has an optical amplification function, it is possible to reduce noise by compensating for attenuation of the amount of light by the optical fiber 8. However, the size of a light receiving element having an optical amplification function may increase. In the present embodiment, the light receiving element 9 is integrated with the optical fiber 8, but may be a separate body. If no space problem occurs near the sample cell 6, the probe light P may be directly received by the light receiving element 9 without using the optical fiber 8.

  The direction in which the optical fiber 8 is attached is not particularly limited as long as the probe light P emitted from the semiconductor laser light emitting unit and transmitted through the sample cell 6 (thermal lens) can be received. However, as shown in FIG. 1, when the optical fiber 8 is arranged along the traveling direction when the probe light P passes through the sample cell 6, the size of the optical portion (optical unit) increases. There is a risk of hindering the portable size. Although a method of arranging the optical fiber 8 in a curved state can be adopted, there is a limit to miniaturization of the optical part due to the influence of the tolerance on the bending of the optical fiber 8.

  Therefore, as shown in FIG. 2 (the same or corresponding parts are given the same reference numerals as in FIG. 1), the probe light P is substantially perpendicular to the traveling direction when the probe light P passes through the sample cell 6. Thus, it is preferable to arrange the optical path 8 such as a prism and a mirror in front of the light receiving surface of the optical fiber 8. In this way, if the optical path of the probe light P transmitted through the sample cell 6 is bent by the optical path changing means 10 and the probe light P is guided to the light receiving surface of the optical fiber 8, the size of the optical portion can be reduced. it can. Of course, the probe light P may be directly received by the light receiving element 9 without using the optical fiber 8, and in this case, it is not necessary to consider the tolerance for bending of the optical fiber 8.

  In FIG. 2, the excitation light E is coaxial with the probe light P by the beam splitter 4 (no reflector is used), and the relationship between the incident angles of the excitation light E and the probe light P is shown in FIG. However, even with such a configuration, there is no problem in the operation as a thermal lens spectroscopic analyzer. Needless to say, the beam splitter 4 in this case should have a sufficiently high transmittance with respect to the probe light P and a sufficiently high reflectance with respect to the excitation light E.

  Next, the signal processing part of the thermal lens spectrometer will be described. The signal processing part generates a signal for processing the electrical signal output from the light receiving element 9 (for example, a personal computer) and a modulation signal used in common with the first semiconductor laser light emitting means 1 and the signal processing means. Modulation signal generating means. This modulation signal generating means also has an interface function between the first semiconductor laser light emitting means 1, the second semiconductor laser light emitting means 2, the light receiving element 9 and the signal processing means. Is converted into a digital signal and output. If the modulation signal generating means has a form that can be inserted into, for example, a slot provided in the signal processing means, it is effective for miniaturization of the thermal lens spectroscopic analyzer.

  According to such a configuration, the thermal lens spectroscopic analyzer can be configured without using a large lock-in amplifier, so that the weight and size of the thermal lens spectroscopic analyzer can be carried. be able to. Further, it is difficult to directly read the change of the probe light P by the thermal lens by the electric signal output from the light receiving element 9 due to the problem of noise. Therefore, the intensity of the excitation light E is varied (switched between ON and OFF) according to the frequency of the modulation signal generated by the modulation signal generating means, and the size of the thermal lens is varied at the frequency. Then, the intensity of the probe light P also varies with the frequency. Then, only the change in the probe light P synchronized with the modulation signal is taken out by the signal processing means, so that the influence of noise on the thermal lens signal can be removed.

The driving source of the thermal lens spectroscopic analyzer is not particularly limited, but in order to make the thermal lens spectroscopic analyzer portable, it is preferable that the thermal lens spectroscopic analyzer is operable by a battery. . This battery may or may not be built in the thermal lens spectroscopic analyzer. Further, the first laser light emitting means 1, the second laser light emitting means 2 and the signal processing means may be driven by a common battery.
Since such a thermal lens spectroscopic analyzer has a small signal processing part as well as an optical part, it is compact and lightweight and portable.

〔Example〕
The present invention will be described more specifically with reference to the following examples. FIG. 3 is a configuration diagram illustrating the configuration of the thermal lens spectroscopic analysis apparatus of the present embodiment, and FIG. 4 is a diagram illustrating the configuration of an optical portion (optical unit) in the thermal lens spectroscopic analysis apparatus of FIG. is there. Since the configuration of the thermal lens spectroscopic analyzer of the present embodiment is almost the same as that described above, the description of the same part is omitted and only the different part will be described. In addition, optical components such as lenses used in the present embodiment may be commercially available or made by themselves as long as they have similar characteristics.

The thermal lens spectroscopic analyzer of the present embodiment includes an optical part (optical unit) that performs thermal lens measurement and a signal processing part that performs thermal lens signal processing. A power source such as a battery may be built in or may not be built in.
The optical unit controls the output of the semiconductor laser light emitting unit, the light receiving means for receiving and detecting the probe light, and outputting an electric signal corresponding to the light intensity, and the first semiconductor laser light emitting means and the second semiconductor laser light emitting means. Electric parts (laser driver) to be performed, and signal processing parts for performing processing such as amplifying an electric signal output from the light receiving means.

  The signal processing part is composed of a personal computer which is signal processing means, and a first semiconductor laser light emitting means, a second semiconductor laser light emitting means, a light receiving means, and an interface unit which connects the personal computer. The interface unit has a function of converting an analog signal output from the light receiving unit into a digital signal and taking it into a personal computer, and also has a function as the above-described modulation signal generating unit. The semiconductor laser light emitting unit is housed in a rectangular parallelepiped case having a length of 85 mm, a width of 80 mm, and a height of 25 mm. In addition, the semiconductor laser light emitting unit, the light receiving means, the electrical parts for controlling the outputs of the first semiconductor laser light emitting means and the second semiconductor laser light emitting means, and processing such as amplifying the electric signal output from the light receiving means An optical unit incorporating a signal processing component to be performed is housed in a rectangular parallelepiped case having a length of 200 mm, a width of 140 mm, and a height of 70 mm. Although not shown in FIG. 3, the electrical components can be configured so that the operation can be controlled by a personal computer via the interface unit.

  For signal processing in a personal computer, an algorithm used in a conventional lock-in amplifier may be applied to software. As for the clock used for modulating the excitation light and for synchronizing with the modulation of the excitation light during signal processing, the clock mounted in the personal computer may be used as it is, but the signal processing Depending on the operating status of other software, the clock signal may fluctuate, and synchronization may not be achieved. In such a case, the problem can be solved by causing the interface unit to retain the function as the modulation signal generating means as in the present invention.

  As the excitation light source 21 (first semiconductor laser light emitting means), a semiconductor laser light emitting device (ML101J17, manufactured by Mitsubishi Electric Corporation) having a wavelength of 658 nm and a rated output of 60 mW was used. Further, a semiconductor laser light emitting device (DL-7140-201S, manufactured by Sanyo Electric Co., Ltd.) having a wavelength of 782 nm and a rated output of 80 mW was used for the probe light source 22 (second semiconductor laser light emitting means). These semiconductor laser light emitting devices can perform output control and current control by a self-made laser driver (LD driver). The actual output can be adjusted by changing the value of the variable resistor provided in the semiconductor laser light emitting device.

  This LD driver is connected to a personal computer via a PCI card (DAQCard6062E, manufactured by National Instruments) as an interface unit, and has a function of adjusting the output, current, and modulation frequency of the semiconductor laser light emitting device by the personal computer. ing. In addition, a high frequency of 350 MHz is superimposed on both the excitation light and the probe light to reduce the influence of noise generated by the return light.

As the collimator lens 23 for excitation light, a lens having an effective diameter of 5 mm and a focal length of 20 mm was used. The probe light collimator lens 24 was a lens having an effective diameter of 5 mm and a focal length of 25 mm.
Further, a polarization-dependent beam splitter having a transmittance of about 100% for p-polarized light and a reflectance of about 100% for s-polarized light was used as the beam splitter 26 for making the excitation light and the probe light coaxial. . In this case, since the excitation light is s-polarized light and the probe light is p-polarized light, the power loss in the beam splitter 26 is almost zero.

  Further, a lens having a numerical aperture of 0.1 and a focal length of 25 mm was used as the condensing lens 27 that condenses the excitation light and the probe light. The condensing lens 27 has the same optical characteristics as the probe light collimator lens 24. In order to guide the excitation light and the probe light that have passed through the beam splitter 26 to the condenser lens 27, a self-made reflector prism 28 that refracts both the lights by 90 ° was used.

  Also, the output power fluctuates due to temperature and other factors in the semiconductor laser light emitting device, and fluctuations in the output power lead to fluctuations in the thermal lens signal, so there is some stabilization when using the semiconductor laser light emitting device in the thermal lens detection system. It is desirable to take measures. As shown in FIG. 4, in this embodiment, a front monitor is employed for both the excitation light and the probe light in order to stabilize the output power. The excitation light is guided to the Si PIN photodiode 32 (S2506-02, manufactured by Hamamatsu Photonics Co., Ltd.) by the beam splitter 31 having a reflectivity of 4%, and the output is monitored to provide feedback for suppressing fluctuations. Similarly, the probe light is guided to the Si PIN photodiode 34 by the beam splitter 33, and the output is monitored to provide feedback for suppressing fluctuations.

  Next, an optical system used for the light receiving means will be described. Excitation light that has passed through the sample cell is removed by an excitation light cut filter (03FCG115, manufactured by Melles Griot) (not shown) installed in front of the light receiving surface of the optical fiber. The probe light that has passed through the excitation light cut filter is guided to the light receiving element by an optical fiber having a core diameter of 500 μm and converted into an electrical signal. Note that a Si photodiode with a preamplifier (S7998, manufactured by Hamamatsu Photonics Co., Ltd.) was used as the light receiving element. However, the type of the light receiving element is not particularly limited as long as it converts the probe light into an electric signal corresponding to the light intensity.

  FIG. 5 is a diagram illustrating a signal flow in the entire thermal lens spectroscopic analyzer. The output signal from the photodiode (light receiving element) is I / V converted by a preamplifier (corresponding to the signal processing component described above) mounted directly on the photodiode by bump connection, and only the AC component is output by the AC amplifier. Amplified and output, but further passes through an anti-aliasing filter (fc = 10 kHz) for the purpose of noise removal, and is output to an interface unit with a personal computer via an SMB cable. The output signal from the photodiode is A / D converted at 12-bit accuracy in this interface unit, and then sent to a personal computer as signal processing means. If this personal computer is assumed to be portable, a notebook type is preferable. However, the personal computer is not particularly limited and may be a desktop type.

  The thermal lens signal captured by the personal computer is subjected to signal processing equivalent to the algorithm used for the lock-in amplifier by software (LABVIEW 6.0, manufactured by National Instruments) and displayed on the display screen of the personal computer. And the change over time of the signal value is recorded. Here, in order to perform signal processing similar to that of the lock-in amplifier, it is necessary to use a modulation signal synchronized with the modulation signal for modulating the excitation light.

  The personal computer has a clock function, and this clock function can be used as a synchronization signal for excitation light modulation and signal processing. Not easily realized. That is, since the clock signal received from the personal computer is affected by various processes performed by the personal computer, it is unsuitable for use in precise signal processing equivalent to a lock-in amplifier. Thus, the above-mentioned problems have been solved by providing an interface unit provided for A / D converting the output from the photodiode and taking it into a personal computer, also with a function as a clock transmission source.

  In the analysis, a glass cell (manufactured by Mito Rika Glass Co., Ltd.) having an optical path length of 2 mm was used as a sample cell, and a brilliant green aqueous solution having a concentration of 5 μmol / L was used as a sample. FIG. 6 shows an example of the analysis result. In the graph of FIG. 6, the signal processing is performed by the result of this embodiment (the signal processing is performed by software on the personal computer) and the lock-in amplifier (5610B, manufactured by NF Circuit Block) which is a commercially available hardware. The results when plotted are plotted. As can be seen from FIG. 6, almost the same result was obtained in any case.

It is a block diagram which shows one Embodiment of the thermal lens spectroscopy analyzer of this invention. It is a block diagram which shows the modification of the thermal lens spectroscopic analyzer of embodiment. It is a block diagram explaining the structure of the thermal lens spectroscopic analyzer of an Example. It is a figure explaining the structure of the optical part (optical unit) among the thermal lens spectroscopy analyzers of FIG. It is a figure which shows the flow of the signal in the whole thermal lens spectroscopy analyzer. It is a figure which shows the analysis result by the thermal lens spectroscopic analyzer of an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st laser light emission means 2 2nd laser light emission means 6 Sample cell 8 Optical fiber 9 Light receiving element 10 Optical path change means E Excitation light P Probe light 21 Light source of excitation light 22 Light source of probe light

Claims (7)

A thermal lens spectroscopic analyzer that enters probe light into a thermal lens generated in a sample by incidence of excitation light and analyzes the sample based on a change by the thermal lens of the probe light at that time,
The first semiconductor laser light emitting means constituting the light source for the excitation light, the second semiconductor laser light emitting means constituting the light source for the probe light, and the probe light that has passed through the thermal lens are received according to the light intensity. A light receiving means for outputting an electrical signal; a signal processing means for processing the electrical signal and outputting an analysis result; and a modulation signal used in common for the first semiconductor laser light emitting means and the signal processing means. And a modulation signal generating means.   The modulation signal generating means has an interface function between the first semiconductor laser light emitting means, the second semiconductor laser light emitting means, the light receiving means and the signal processing means, and an analog signal inputted in the interface function The thermal lens spectroscopic analysis apparatus according to claim 1, wherein the thermal lens spectroscopic analysis apparatus converts the signal into a digital signal and outputs the signal.   A semiconductor laser light emitting unit incorporating the first semiconductor laser light emitting means and the second semiconductor laser light emitting means is provided, and the semiconductor laser light emitting unit has a shape that can be accommodated in a rectangular parallelepiped having a length of 85 mm, a width of 80 mm, and a height of 25 mm. The thermal lens spectroscopic analysis device according to claim 1 or 2, wherein:   The semiconductor laser light emitting unit, the light receiving means, electrical components for controlling the outputs of the first semiconductor laser light emitting means and the second semiconductor laser light emitting means, and a signal for processing an electrical signal output from the light receiving means The thermal lens according to claim 3, further comprising an optical unit in which a workpiece is incorporated, and the optical unit having a shape that can be accommodated in a rectangular parallelepiped having a length of 200 mm, a width of 140 mm, and a height of 85 mm. Spectroscopic analyzer.   The light receiving means includes a light receiving unit that receives the probe light transmitted through the thermal lens, and a detection unit that detects the received probe light and outputs an electrical signal corresponding to the light intensity, 5. The thermal lens spectroscopic analysis apparatus according to claim 1, wherein the light receiving unit includes an optical fiber that receives the probe light transmitted through the thermal lens and guides the probe light to the detection unit.   6. The thermal lens spectroscopic analyzer according to claim 5, wherein optical path changing means for changing the optical path of the probe light is disposed in front of the light receiving surface of the optical fiber.   The thermal lens spectroscopic analyzer according to any one of claims 1 to 6, wherein the thermal lens spectroscopic analyzer is operable by a battery.

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