KR20120073108A - Optical instrument - Google Patents

Abstract

PURPOSE: An optical analyzing device is provided to reduce measurement errors and to prevent an increase of operation costs caused by exchanging a reference correction member. CONSTITUTION: An optical analyzing device(100) comprises a light collecting optical system(3), a detecting optical system(4), a measurement cell(5), a reference correcting member(6), and a conveying tool(7). The light collecting optical system collects lights emitted from a light source(2). The detecting optical system is on an optical path of the lights collected by the light collecting optical system, thereby detecting the lights. The measurement cell is movable on between the light collecting optical system, a measurement position, and a withdraw position. The reference correcting member is movable on between the light collecting optical system, the measurement position, and the withdraw position. A focal position of lights penetrated at a reference position is roughly the same with a focal position of lights penetrated the measurement cell so that the reference correcting member is constituted. The conveying tool conveys the measurement cell to the measurement position and the reference correcting member to the reference position.

Description

Optical analysis device {OPTICAL INSTRUMENT}

The present invention relates to an optical analysis device such as a spectroscopic analysis device.

As a conventional spectroscopic analyzer, as shown in Patent Literature 1, a light source, a condenser for condensing light from the light source, a spectroscopic analyzer for spectroscopically analyzing light from the light source with a multi-channel detector, and a condenser lens And a measurement cell arranged between the spectroscopic analyzer.

Absorption spectroscopy is used for the concentration measurement of this spectroscopic analyzer. Generally with this absorption spectroscopy, concentration c is computed by multiplying the absorbance spectrum Abs ((lambda) i) by the calibration curve M _i previously calculated by calibration (refer the following formula).

The absorbance spectrum Abs (λi) is expressed by the following formula in terms of the intensity Io (λi) of the incident light into the measurement cell and the intensity Is (λi) of the transmitted light from the measurement cell.

Here, it is difficult to directly measure the intensity Io (λi) of the incident light, and in the conventional spectroscopic analyzer, the light measured by the spectroscopic analyzer is measured in a state where a measurement cell is removed between the condenser lens and the spectroscopic analyzer (reference photometry). The intensity, that is, the intensity Ir (λi) of the reference light is substituted.

By the way, when there is a measurement cell on the optical path and there is no measurement cell, there is a difference in refractive index, and as shown in Figs. 6A and 6B, the luminous flux of light incident on the spectroscopic analysis part, specifically, The focus position changes. As a result, an error occurs in the amount of light of the reference light obtained by the spectroscopic analyzer, and the absorbance spectrum Abs (λi) changes, resulting in an error in the calculated concentration.

Therefore, in the spectroscopic analyzer of Patent Literature 1, in order to correct a change in the focus position with or without a measuring cell, a refractive index correction member is disposed between the condenser lens and the spectroscopic analyzer in reference light measurement (Fig. 6 (C)). This refractive index correction member is comprised using optical glass, such as quartz.

By the way, when the density | concentration measurement of the chemical liquid containing hydrofluoric acid is performed, for example with the said spectroscopic analyzer, the introduction and derivation of the chemical liquid to a measuring cell use the fluororesin piping which has corrosion resistance with hydrofluoric acid.

However, part of the hydrofluoric acid in the chemical liquid flowing through the fluorine resin pipe passes through the pipe wall of the pipe and is released to the outside as hydrogen fluoride gas. In addition, hydrogen fluoride gas is also released from the chemical liquid tank storing the chemical liquid. Then, there exists a problem that hydrogen fluoride gas which is a corrosive gas exists in the atmosphere in which a refractive index correction member is arrange | positioned, and the surface of the refractive index correction member which consists of optical glass corrodes and becomes cloudy. Thereby, there exists a problem that the amount of reference light which can be obtained by reference light measurement falls, and an absorbance changes and an error arises in a calculated density.

Moreover, when the refractive index correction member is corroded and cloudy, there is a problem that it is necessary to replace the member and to manage the replacement time. In addition, there is a problem that it is necessary to prepare a new refractive index exchanging member separately, or that the replacement work is complicated and labor takes, resulting in an increase in operating cost.

Patent Document 1: Japanese Unexamined Patent Publication No. 2002-82050

Accordingly, the present invention is to reduce the influence of the corrosive gas on the reference correction member for focus position correction, to reduce the measurement error of the optical analysis device, and to solve various problems caused by replacement of the reference correction member, It is the main sought task.

That is, the optical analysis device which concerns on this invention is provided on the condensing optical system which condenses the light emitted from the light source, the optical system of the light condensed by the condensing optical system, and the detection optical system which detects the light, the said condensing optical system, and the said A measurement cell movable between a measurement position positioned on the optical path between the detection optical systems, and a retracted position evacuated from the measurement position, a reference position positioned on the optical path between the condensing optical system and the detection optical system, and A reference correction member movable between the retracted positions retracted from the reference position and configured such that the focal position of the light passing at the reference position is approximately equal to the focal position of the light passing through the measurement cell at the measurement position; Move the measurement cell and the reference correction member to selectively measure the measurement cell. A position mechanism or a movement mechanism for making the reference correction member the reference position, wherein an outer surface portion intersecting the optical path at least at the reference position of the reference correction member is formed of a corrosion resistant material having corrosion resistance against corrosive gas; It is characterized by being.

In this case, since the reference correction member can be provided on the optical path in the reference light measurement, the change in the focus position with or without the measurement cell can be corrected, and the error of the measurement result can be reduced. In particular, since the outer surface portion intersecting the optical path at the reference position is formed of a corrosion resistant material, the influence of the reference correction member from the corrosive gas in the reference light measurement can be reduced. Thereby, regardless of the presence of corrosive gas, the error of the reference light measurement can be reduced, and the error of the measurement result of the optical analysis device using the result of the reference light measurement can be reduced. In addition, since the corrosion of the reference correction member in the reference light measurement can be ignored, it is not necessary to replace the reference correction member, and various conventional problems caused by the replacement of the reference correction member can be solved. In addition, by moving the measuring cell and the reference correction member forward and backward with respect to the condensing optical system and the detecting optical system, the condensing optical system and the detecting optical system are common, so that the position of the light source is shifted or the blur of the condenser lens is compared with the case where a plurality of optical paths are provided. This can reduce the impact. Moreover, only one condensing optical system needs to be prepared, and the structure which guides the light from a light source to a detection optical system is comparatively simple, and can be manufactured at low cost.

When the entirety of the reference correction member is formed of a corrosion resistant material, there is a possibility that it becomes very expensive depending on the type of corrosion resistant material (for example, sapphire). In this case, the reference correction member seals between the optical glass and the corrosion resistant plate made of the corrosion resistant plate made of the corrosion resistant material provided to face each of the light incident surface and the light exit surface of the optical glass. It is preferable to have a sealing member for the purpose of blocking.

In order to reduce the component score of the components of the reference correction member as much as possible and to provide corrosion resistance to corrosive gas, the reference correction member is configured to coat the corrosion resistant material on at least the light incident surface and the light exit surface of the optical glass. It is preferable that it is done.

In order to reduce the types of components of the reference compensating member and to be able to cope with the focal positions of various measurement cells, the reference compensating member is formed by overlapping a corrosion resistant plate made of a plurality of corrosion resistant materials through a spacer. It is preferable that it is comprised.

According to the present invention configured as described above, by reducing the influence of the corrosive gas on the reference correcting member, it is possible to reduce the measurement error of the optical analysis device and to prevent the increase in operating cost due to the replacement of the reference correcting member.

BRIEF DESCRIPTION OF THE DRAWINGS The overall schematic which shows the structure of the spectroscopic analyzer of this embodiment schematically.
2 is a perspective view showing a measurement cell and a reference correction member of the embodiment;
3 is a cross-sectional view showing a measurement cell and a reference correction member of the embodiment;
4 is a schematic diagram showing a focal position of the measurement cell and the reference correction member of the embodiment.
5 is a schematic diagram illustrating a modification of the reference correction member.
6 is a schematic diagram showing a focal position of a condenser lens with or without a conventional refractive index correction member.

EMBODIMENT OF THE INVENTION Below, one Embodiment at the time of applying to a spectroscopic analyzer as an example of the optical analyzer which concerns on this invention is described with reference to drawings.

The spectroscopic analysis apparatus 100 which concerns on this embodiment is installed through the chemical liquid piping which supplies chemical liquids, such as hydrofluoric acid, etc. which were installed in the semiconductor manufacturing apparatus, for example, and absorbs the density | concentration of chemical liquids (sample liquid), such as hydrofluoric acid, etc. It is measured using a measuring method. On the other hand, the concentration of the chemical liquid and the like are controlled using the concentration thus obtained.

Specifically, as shown in FIG. 1, this is a light converging optical system 3 for condensing light emitted from the light source 2 and the light source 2, and an optical path L image of light condensed by the condensing optical system 3. The collecting optical system 3 and the detection optical system 4 which detect the light, and the measuring cell 5 which is movable on the optical path L between the condensing optical system 3 and the detecting optical system 4. The reference correction member 6 which can move on the optical path L between the optical systems 4, and the movement mechanism 7 which moves the measuring cell 5 and the reference correction member 6 are provided. On the other hand, the spectroscopic analyzer 100 is provided with a computer (not shown) as an arithmetic control unit that controls the entire apparatus or performs concentration calculation or the like based on the output from the multichannel detector 45 described later.

The light source 2 is a continuous spectrum light source which consists of a halogen lamp etc., for example.

The condensing optical system 3 is provided in the light emitting direction of the light source 2 to condense the light emitted from the light source 2, and is configured using a condenser lens in this embodiment.

The detection optical system 4 spectra the light collected by the condensing optical system 3 at each wavelength, and detects each of those wavelength components. Specifically, the detection optical system 4 is a collie composed of an incident slit 41 provided in the vicinity of a focal position of the light of the condensing optical system 3 and a concave mirror that makes light incident from the incident slit 41 a parallel beam. A mate lens 42, a diffraction grating 43 for receiving the parallel light flux from the collimating lens 42 and spectroscopy for each wavelength, and a concave mirror for condensing light of each wavelength spectroscopically diffracted by the diffraction grating 43 And a multi-channel detector 45 for detecting light of each wavelength condensed by the camera lens 44. The absorbance spectrum Abs (λi) can be obtained based on the light intensity signal obtained by the multichannel detector 45.

The measurement cell 5 is a flow cell type, and as shown in FIGS. 2 and 3, a cell body 51 having an accommodating space 5S for accommodating a chemical liquid therein, and the cell body 51. And a liquid introduction portion 52 for introducing the chemical liquid into the storage space 5S, and a liquid extraction portion 53 for extracting the chemical liquid from the storage space 5S. On the other hand, the fluorine resin piping H is connected to the liquid introduction part 52 and the liquid extraction part 53.

In particular, as shown in FIG. 3, the cell main body 51 includes a main body portion 511 having a receiving recess 511a, a pair of light transmitting members 512 accommodated in the receiving recess 511a, and A spacer 513 interposed between the pair of light transmitting members 512 and a fixing member 514 for fixing the pair of light transmitting members 512 and the spacer 513 in the receiving recess 511a. ). In the cell main body 51 configured as described above, the accommodation space 5S is formed by the pair of light transmitting members 512, the spacer 513, and the like. In the storage space 5S, liquid tightness is ensured by a sealing member such as an O-ring.

The pair of light transmitting members 512 are formed of a corrosion resistant material having corrosion resistance against chemical liquids such as hydrofluoric acid. The translucent member 512 of this embodiment is a sapphire plate material formed using sapphire which has corrosion resistance with hydrofluoric acid and shows high light transmittance with respect to an ultraviolet region. And when the measuring cell 5 is in the measurement position P mentioned later, this light transmitting member 512 intersects with the optical path L of the light condensed by the said condensing optical system 3. On the other hand, in applications other than spectroscopic analysis in the ultraviolet region, corrosion-resistant materials such as fluororesin may be used.

The measuring cell 5 comprised in this way is measured position P located on the optical path L between the said condensing optical system 3 and the detection optical system 4 by the moving mechanism 7 mentioned later, and this measuring position. It is movable between the evacuation positions Q retracted from P (see FIG. 4).

In the reference light measurement, the reference correction member 6 corrects the change in the focus position of the light collected by the light converging optical system 3. As shown in Figs. 2 and 3, the reference correcting member 6 is integrally provided with the measuring cell 5, and is provided with a second body installed in the main body 511 of the cell main body 51. It is accommodated in the accommodating recess 511b. And this reference correction member 6 is comprised so that the focal position of the light which passed by the reference position R mentioned later is substantially the same as the focal position of the light which passed through the measuring cell 5 in the said measurement position P. In addition, the detail of the reference correction member 6 is mentioned later.

In addition, the reference correction member is evacuated from the reference position R located on the optical path L between the condensing optical system 3 and the detection optical system 4 and the reference position R by the moving mechanism 7 described later. It is possible to move between one retracted position S and FIG. 4.

The movement mechanism 7 moves the measurement cell 5 and the reference correction member 6, and optionally sets the measurement cell 5 as the measurement position P or the reference correction member 6 as the reference position R. The measuring cell 5 and the reference correction member 6 of the present embodiment are integrated in parallel with respect to the optical path L of the light collected by the condensing optical system 3, and the moving mechanism 7 includes the measuring cell ( 5) and the reference correction member 6 are moved forward and backward integrally in the direction orthogonal to the optical path L. FIG. On the other hand, although not shown in figure, the structure of the movement mechanism 7 is equipped with a drive motor and the rack and pinion mechanism which converts the rotational motion of the drive shaft of this motor into a linear motion.

Here, the positional relationship between the measurement position P and the retraction position Q of the measurement cell 5, and the reference position R and the retraction position S of the reference correction member 6 will be described with reference to FIG. The measurement position P of the measurement cell 5 and the reference position R of the reference correction member 6 are approximately the same position with respect to the condenser lens 3. In addition, when the measurement cell 5 is at the measurement position P, the reference correction member 6 is at the retracted position S (see top of FIG. 4), and when the reference correction member 6 is at the reference position R, the measurement cell (5) is at the retracted position Q (see bottom of FIG. 4). On the other hand, the measurement position P of the measurement cell 5 is a position for sample optical measurement, and the reference position R of the reference correction member is a position for reference optical measurement.

And the reference correction member 6 of this embodiment is formed with the corrosion-resistant material which has at least the outer surface part 6A which cross | intersects the optical path L at the reference position R with corrosion resistance with respect to the hydrogen fluoride gas which is a corrosive gas.

Specifically, as shown in FIG. 3, the reference correction member 6 is provided to face the optical glass 61 and the light incident surface 61a and the light emitting surface 61b of the optical glass 61, respectively. The corrosion resistant plate material 62 which consists of a corrosion resistant material, and the sealing member 63, such as an O-ring which seals and closes between the optical glass 61 and the corrosion resistant plate material 62, and is sealed. These components 61-63 are fixed by the fixing member 8 in the state accommodated in the 2nd accommodation recessed part 511b. The corrosion resistant plate material 62 of this embodiment is a sapphire plate material formed using sapphire which has corrosion resistance with hydrofluoric acid and shows high light transmittance with respect to an ultraviolet region.

In this embodiment, the light incident surface and the light emitting surface of the reference correction member 6 are covered by covering the entire light incident surface 61a and the light emitting surface 61b of the optical glass 61 with the sapphire plate material 62. The whole is formed by the corrosion resistant material. As a result, the outer surface portion 6A of the reference correction member 6 can be provided with corrosion resistance, and the optical glass 61 can be prevented from corroding and clouding by the hydrogen fluoride gas. On the other hand, the sapphire plate material 62 and the sealing member 63 should just be airtightly provided by the optical glass 61 so that the part which may cross | intersect the optical path in the optical glass 61 may be enclosed. That is, the sapphire plate material 62 and the sealing member 63 should just be provided so that the optical glass 61 may cover the outer surface part which intersects the optical path L at the reference position R airtightly.

In order to correct the focus position by the reference correction member 6 configured as described above, the thickness of the optical glass 61 is adjusted while considering the thickness of the sapphire plate material 62. Since the sapphire plate of several mm in thickness is low in demand and generally expensive, it is preferable to use a thin sapphire plate in demand and inexpensive. Here, although it changes with the structure of the measuring cell 5, when the thickness of one sapphire plate material 62 is 0.5 mm, for example, the thickness of the optical glass 61 is about 6 mm-15 mm, for example. to be. That is, the optical glass 61 corrects most of the focus position correction.

<Effect of this embodiment>

According to the spectroscopic analysis apparatus 100 which concerns on this embodiment comprised in this way, since the reference correction member 6 is provided in the optical path L in a reference measurement, the change of the focal position by the presence or absence of the measurement cell 5 is prevented. It can correct and reduce the error of a measurement result.

In particular, since the outer surface portion 6A intersecting the optical path at the reference position R is formed of a sapphire plate, the influence of the reference correction member 6 from the hydrogen fluoride gas on the reference measurement can be reduced. Thereby, the error of a reference measurement can be reduced regardless of presence of hydrogen fluoride gas, and the error of the measurement result of the spectroscopic analyzer 100 using the result of the said reference measurement can be reduced. In addition, since the corrosion of the reference correction member 6 in the reference optical measurement can be neglected, it is not necessary to necessarily replace the reference correction member 6, and the conventional art accompanying the replacement of the reference correction member 6 is required. Various problems can be solved.

In addition, since the condensing optical system 3 and the detecting optical system 4 are shared by moving the measuring cell 5 and the reference correction member 6 with respect to the condensing optical system 3 and the detecting optical system 4, Compared with the case of providing the optical path of the light source, the effect of the positional difference of the light source 2 and the blurring of the condensing lens 3 can be reduced. Furthermore, only one condensing optical system 3 needs to be prepared, or the structure until the light from the light source 2 is guided to the detection optical system 4 is relatively simple, so that it can be produced at low cost.

<Other Modified Embodiments>

In addition, this invention is not limited to the said embodiment.

For example, as the reference correction member 6, as shown in FIG. 5A, at least the light incident surface 61a and the light emitting surface 61b of the optical lens 61 may be coated with a corrosion resistant material. . 5A shows the case where the entire outer surface of the optical glass 61 is coated. In this case, the number of parts of the components of the reference correction member can be reduced, and the assembly work can be simplified.

In addition, as the reference correction member 6, optical elements other than optical glass may be used, and as shown in FIG. 5 (B), the corrosion resistant plate material which consists of several sheets of corrosion resistant material (for example, The sapphire plate material 62 may be laminated together via the spacer 64. In this case, it is possible to correspond to the focal position of various measurement cells by adjusting the number of superimposed sapphire plates.

Moreover, in the said embodiment, although sapphire was used as a corrosion-resistant material in order to acquire the absorbance spectrum in an ultraviolet region, when using for the use other than an ultraviolet region, you may use a fluorine resin other than sapphire.

In addition, in the said embodiment, although the measuring cell and the reference correction member are integrally provided, you may comprise as another member and also make it move selectively to a measurement position or a reference position by a moving mechanism.

Furthermore, in addition to hydrogen fluoride gas, you may comprise so that corrosion resistance may be carried out with corrosive gas, such as chlorine gas.

In addition, although the said embodiment demonstrated the spectroscopic analyzer using the absorbance measuring method, it is applicable also to the optical analyzer which performs another reference optical measurement.

In addition, this invention is not limited to the said embodiment, Needless to say that various deformation | transformation is possible in the range which does not deviate from the meaning.

100 ... Spectroscopic Analyzer (Optical Analyzer)
2 ... light source
3 ... condenser lens (condensing optics)
4 ... detection optical system
P ... measuring position
Q ... evacuation position
5 ... measuring cell
R ... reference position
S ... evacuation position
6 ... reference compensation member
6A ... exterior section intersecting the light path
61 ... optical glass
62 ... sapphire plate (corrosion resistant plate)
63: seal member
7: moving mechanism

Claims (4)

A condensing optical system that condenses the light from the light source,
A detection optical system provided on the optical path of the light collected by the condensing optical system and detecting the light;
A measurement cell movable between a measurement position located on an optical path between the condensing optical system and the detection optical system, and an evacuation position evacuated from the measurement position;
A measurement in which the reference position located on the optical path between the condensing optical system and the detection optical system and the evacuation position withdrawn from this reference position are movable, and the focal position of the light passing at the reference position is at the measurement position A reference correction member configured to be approximately equal to the focal position of the light passing through the cell,
A movement mechanism for moving the measurement cell and the reference correction member to selectively move the measurement cell to the measurement position or the reference correction member to the reference position,
And an outer surface portion intersecting the optical path at least at the reference position of the reference correction member is formed of a corrosion resistant material having corrosion resistance against corrosive gas. The anticorrosive plate material according to claim 1, wherein the reference correction member is made of an optical glass, a corrosion resistant plate made of the corrosion resistant material provided to face each of the light incidence plane and the light emission face of the optical glass, and the optical glass and the corrosion resistant plate. An optical analysis device having a sealing member that seals and seals the gap between them. The optical analysis device according to claim 1, wherein the reference correction member is formed by coating optical glass with the corrosion resistant material on at least a light incident surface and a light emitting surface. The optical analysis device according to claim 1, wherein the reference correction member is configured by overlapping a plurality of corrosion resistant plate materials made of the corrosion resistant material through spacers.

Images