Abstract:
In an analysis system for detecting amounts of components contained in samples, many samples can be measured simultaneously in the whole of the system by use of compact inexpensive photometers. An LED with low heat generation and a long life span is used as a light source. Compactness is achieved by bended optical axis instead of a straight one. Components for bending an optical axis and components for condensing light to ensure an amount of light are in common use to reduce the number of components. Compactness, reduction of the number of components, and integration achieve easy optical axis alignment and precise measurement.

Description:
TECHNICAL FIELD 
     The present invention relates to a liquid analysis system for detecting amounts of components contained in a sample and to a technology for making a photometer, which is a main of the system, compact and inexpensive and for making the entirety of the liquid analysis system inexpensive. 
     BACKGROUND ART 
     As an analysis device for detecting amounts of components contained in a sample, a spectrometer is widely used in which a sample solution in a reaction vessel is illuminated with white light from, e.g., a halogen lamp, the light passing through the sample solution is dispersed by a diffraction grating to obtain a required wavelength component, and its optical absorbance is determined to measure an amount of a target component. Alternatively, white light may be dispersed by a diffraction grating and then a sample solution may be illuminated with the light. As one example, Patent Literature 1 discloses an automatic analysis device. 
     Patent Literature 1 and Patent Literature 2 disclose analysis devices as examples in which a lens and a mirror are used to condense light from a light source of, e.g., a halogen lamp and to illuminate a sample precisely with the light. 
     As an analysis device using an LED as a light source instead of the halogen lamp, Patent Literature 4 discloses an analysis instrument and Patent Literature 5 discloses an analysis device. 
     Patent Literature 6 discloses an analysis device as an example using an LED as a light source and using a lens to condense light of the LED and to illuminate a sample with large amounts of light. 
     CITATION LIST 
     Patent Literature 
     
         
         Patent Literature 1: U.S. Pat. No. 3,749,321 
         Patent Literature 2: Japanese Patent Application Laid-Open Publication (JP-A) No. 2007-225339 
         Patent Literature 3: Japanese Patent Application Laid-Open Publication (JP-A) No. 2007-218883 
         Patent Literature 4: U.S. Pat. No. 3,964,291 
         Patent Literature 5: Japanese Patent Application Laid-Open Publication (JP-A) No. 2007-198935 
         Patent Literature 6: Japanese Patent Application Laid-Open Publication (JP-A) No. 2007-225339 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     In the example using a halogen lamp in the above-mentioned related arts, there is a problem that cooling is required because of heat generation of the halogen lamp and precise temperature control using, e.g., cooling water is required to obtain a stable amount of light. There is also a problem that replacement of a halogen lamp is required because the lamp has a short life span and then the replacement is a burden to a user of the device and thus that the layout needs to be considered on the assumption of the lamp replacement in device design to decrease the flexibility of device design. 
     In an optical system using a halogen lamp, there is also a problem that it is difficult to align an optical axis because many components such as a diffraction grating used to disperse white light from a halogen lamp and a lens and mirror used to condense light from a light source and to illuminate a sample precisely with the light are used. 
     The analysis instrument of Patent Literature 4 and analysis device of Patent Literature 5 each use an LED as a light source and have a simple structure using only an LED and a detector, but 
     there is a problem that an amount of light for illuminating a sample is small because a lens, a mirror, etc. for condensing light are not used actively and precise analysis is difficult depending on a purpose of analysis. 
     In the analysis device of Patent Literature 6, which is the above related example using an LED as a light source and a lens to ensure an amount of light by light condensation, multiple photometer units are provided on one stage densely. Therefore, there is a problem that assembly alignment is difficult and there is a problem that it is difficult to respond to the case in which one or some of the multiple photometry units need to be replaced for a change of a wavelength and for maintenance. Additionally, since an optical axis is on one straight line, the occupied area of the reaction table in the radial direction is large. 
     To build an LED photometer, at least a light source, a condensing lens, a slit, and a photo detector shown in  FIG. 1  are required. (A reaction vessel and a sample are not included in the photometer.) The structure using only a light source and photo detector is possible. For precise analysis, condensing components (a lens and a mirror) for ensuring an amount of light are indispensable. To define a cross sectional shape of a light beam and make the amount of light passing through a sample constant or to restrict stray light from entering a detector, a slit is also indispensable. In an automatic biochemistry analyzer for precise analysis using a photometer, to keep a sample temperature in a reaction vessel constant, the reaction vessel is immersed in constant temperature water circulating in a thermostatic bath. To test many samples in short time, multiple reaction vessels are arranged circumferentially to form an integrated reaction vessel disk. The test by a photometer section is conducted while the reaction vessel disk circulates in a ring shaped thermostatic bath concentric with the reaction vessel disk.  FIG. 2  shows only one side of vertical cross sections of a ring-shaped thermostatic bath in an example in which the LED photometer of the above minimum structure is disposed on the thermostatic bath. The thermostatic bath needs a window formed of a transparent member for passing-through the measurement light without leaking constant temperature water. 
     When the LED photometer of the minimum structure is disposed on the thermostatic bath, the light source and condensing lens are disposed outside the ring-shaped thermostatic bath and the photo detector is disposed inside the thermostatic bath as shown in  FIG. 2 . The positional relationship of the light source and photo detector relative to the thermostatic bath may be reverse. Since it is desirable that the slit is as close to the reaction vessel as possible, the slit is disposed inside the thermostatic bath. 
     To maintain the components in their set positions and to make easy the alignment of the optical axis and the assembling, it is desirable that the components of the photometer are assembled integrally to a support/holder, which is attached to the thermostatic bath, as shown in  FIG. 3 . 
     However, to attach the support/holder to the thermostatic bath, there is a problem that it is necessary to gouge the thermostatic bath greatly and sealing for preventing leakage of the constant temperature water etc. thus becomes complicated. 
       FIG. 4  shows a state in which the components except the slit are integrated and attached to the thermostatic bath. In such a state, it is not necessary to gouge the thermostatic bath. 
     A window formed of a transparent member to pass measurement light through without leaking constant temperature water may be provided. However, since the optical axis alignment needs to be conducted in combination with the slit, the optical axis alignment is needed after attaching the integrated components to the thermostatic bath. It is possible to align an optical axis by mechanical precision of the components. As compared to when only the retaining member of  FIG. 3  and the components attached thereto are adjusted by mechanical precision, the slit and the integrated components except the slit need to be precisely attached to the thermostatic bath respectively in the example of  FIG. 4 . Therefore, there is a problem that the thermostatic bath usually having a diameter of 300 mm or over needs high precision. 
     One of objects of the present invention is to contribute to downsizing of the device and to improvement of flexibility of device design. When using a semiconductor light source such as a light emitting diode and a semiconductor laser as a light source, a photometer structure suitable for a semiconductor light source is applied to an analysis device. Accordingly, downsizing of the device can be further facilitated and design flexibility of the device can be improved. 
     Solution to Problem 
     For addressing the problems, a photometer is characterized in including: a light source; a first support transmitting and passing through light emitted from the light source; a detector for detecting light passed through a reaction vessel containing a measurement sample; a second support provided with the detector, the first support and the second support being disposed such that the reaction vessel containing a measurement sample is inserted therebetween; a first reflection section provided to the first support, reflecting light emitted from the light source, and passing the light through the reaction vessel; and a condensing section for condensing light emitted from the light source and passing the light through the reaction vessel. 
     An analysis system is characterized that includes: a reaction vessel for containing a measurement sample; a thermostatic bath containing a constant temperature fluid that immerses therein and retains the reaction vessel; and a photometer on the bottom portion of the thermostatic bath to illuminate the reaction vessel with light. The photometer includes: a light source; a first support transmitting and passing light emitted from the light source therethrough; a detector for detecting light passed through a reaction vessel containing a measurement sample; a second support provided with the detector; and a reflection portion provided to the first support, reflecting light emitted from the light source, and passing the light through the reaction vessel, the first support and the second support being disposed such that the reaction vessel containing a measurement sample is inserted therebetween. 
     The reflection section can use a plane mirror, a parabolic mirror, an elliptic mirror, etc., which can be arranged depending on each feature. 
     A light emitting diode and semiconductor diode generating less heat and having a long life span are used as the light source. An optical axis is not on a straight line but is bent for downsizing. A component for bending the optical axis and a component for condensing light to ensure an amount of light are in common use to reduce the number of components. The downsizing, the reduction of the number of the components, and the integration make the alignment of the optical axis easy. Accordingly, a more precise photometer and analysis system is achieved. 
     Advantageous Effects of Invention 
     According to one embodiment the present invention, by bending an optical axis by use of a reflector, radial sizes of a thermostatic bath of a photometer and a reaction vessel disk can be reduced to contribute to downsizing of the device. Additionally, a condensing lens becomes unnecessary by bending an optical axis by use of a parabolic mirror and an elliptic mirror, the number of components can thus be reduced, and cost reduction becomes possible together with the ease of optical axis alignment. Further, by using a parabolic mirror and an elliptic mirror properly, it becomes possible to use properly a photometer oriented to an amount of light influencing detection sensitivity and a photometer oriented to a characteristic of measurement of a scattering item. The technology for improving a capability of the system can be provided. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a diagram showing the minimum structure required for an LED photometer. 
         FIG. 2  is a diagram of an example in which the LED photometer of the minimum structure is disposed on a thermostatic bath. 
         FIG. 3  is a diagram of an example in which the LED photometer of the minimum structure is integrated and disposed on the thermostatic bath. 
         FIG. 4  is a diagram of the example in which the LED photometer of the minimum structure except a slit is integrated and disposed on the thermostatic bath. 
         FIG. 5  is a diagram showing a structure of a photometer for a liquid analysis system according to the present invention. 
         FIG. 6  is a diagram showing a structure in which the photometer for the liquid analysis systems according to the present invention is attached to the thermostatic bath. 
         FIG. 7  is a diagram showing multiple photometers for the liquid analysis system according to the present invention are attached to the thermostatic bath. 
         FIG. 8  is a diagram showing a structure of the photometer for the liquid analysis system according to the present invention. 
         FIG. 9  is a diagram showing a structure of the photometer for the liquid analysis systems according to the present invention. 
         FIG. 10  is a diagram showing a structure of the photometer for the liquid analysis system according to the present invention. 
         FIG. 11  is a diagram showing a structure of the photometer for the liquid analysis system according to the present invention. 
         FIG. 12  is a diagram showing a situation in which parallel incident light is scattered. 
         FIG. 13  is a diagram showing a situation in which angular incident light is scattered. 
         FIG. 14  is a diagram showing a structure of the photometer for the liquid analysis system according to the present invention. 
         FIG. 15  is a diagram showing a structure of the photometer for the liquid analysis system according to the present invention. 
         FIG. 16  is a diagram showing a structure of the photometer for the liquid analysis system according to the present invention. 
         FIG. 17  is a diagram showing a structure of the photometer for the liquid analysis system according to the present invention. 
         FIG. 18  shows the result of a simulation for the difference in amounts of light by use of a parabolic mirror and an elliptical mirror. 
         FIG. 19  is a diagram showing a structure of the photometer for the liquid analysis systems according to the present invention. 
         FIG. 20  is a diagram showing a structure of the photometer for the liquid analysis system according to the present invention. 
         FIG. 21  is a diagram showing a structure of the photometer for the liquid analysis system according to the present invention. 
         FIG. 22  is a diagram showing a structure of the liquid analysis system according to the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     (Embodiment 1) 
       FIG. 5  is a diagram showing a structure of a photometer for a liquid analysis system according to the present invention (hereinafter described as a photometer). The present photometer is a photometer  11  including: an LED source  1 ; a first support  2  for transmitting or passing light emitted from the LED source  1  therethrough; a first reflector  3  provided to the first support  2 ; a first slit  4  provided to the first support  2 ; a second support  7  provided with a second slit  5  and a photo detector  6 ; a third support  9  for connecting the first support  2  and the second support  7  between which a reaction vessel  13  is disposed a slot  8  is formed; and a condensing lens  10  held by the first support  2  or the third support  9 . As a light source, a light emitting diode (LED) is used in this example, but a semiconductor laser etc. can be also used. 
     The analysis of a measurement sample is conducted by the present photometer  11  attached to a thermostatic bath of a liquid analysis system. Therefore, before explanation of an analysis method, the structure around near a portion where the present photometer of the liquid analysis system is attached and the positional relationship between the portion and the present photometer are explained. 
       FIG. 6  shows part of the liquid analysis system, and shows only one side of vertical sections of a ring shaped thermostatic bath  12  having a U shaped cross section and one side of vertical sections of a reaction vessel disk  14  having multiple reaction vessels  13  arranged on a circumference concentric with the thermostatic bath  12 . The reaction vessel  13  has a light incident surface, a light transmission inner surface, and a light emitting surface, which are arranged parallel to each other and rectangular to an optical axis. The thermostatic bath  12  has a flow path  15  having a U shaped cross section. Constant temperature water  16  kept at a constant temperature circulates in the flow path  15  at a constant liquid level. The reaction vessel disk  14  rotates around a common central axis with the thermostatic bath  12  above the thermostatic bath  12 . The reaction vessel  13  mounted to the reaction vessel disk  14  is submerged in the constant temperature water  16  in the thermostatic bath  12 , and moves inside the flow path  15  of the thermostatic bath  12 . A measurement sample  17  is placed in the reaction vessel  13  for measurement. The photometer  11  is attached to the thermostatic bath  12  from the lower side of the thermostatic bath  12  such that the reaction vessel  13  is movable inside the slot  8 . One or multiple photometers  11  are disposed on a circumference concentric with the thermostatic bath  12 . 
     Analysis of measurement samples by the photometer  11  is conducted when the photometer  11  is attached to the thermostatic bath  12  as mentioned above, the reaction disk  14  rotates, and the reaction vessel  13  containing the target measurement sample  17  moves to a position of the slot  8  of photometer  11 . 
     In the analysis, light emitted from the LED source  1  is condensed to a position of the measurement sample  17  in the reaction vessel  13  by the condensing lens  10 , and reflected by the first reflector  3  to bend the optical axis by substantially 90 degrees. Then, the light illuminates an illumination area controlled to be constant by the first slit  4 . 
     To prevent, e.g., bacterial growth, alkali or acid liquid is usually used for the constant temperature water  16 . Therefore, the first support  2 , the first reflector  3 , the first slit  4 , the second slit  5 , and the third support  9  use glass, metal, and/or resin which are resistant to alkali liquid and acid liquid. The LED source  1 , the photo detector  6 , the condensing lens  10 , etc. are sealed to prevent the intrusion of the constant temperature water  16 . 
     The measurement principle of samples by the analysis system, which is the target of the present photometer, is as follows. 
     A reagent selected by an analysis item is mixed with the measurement sample  17 , and reacts with an analyte component, and absorbs light of a predetermined wavelength in accordance with a ratio of a contained analyte component. Therefore, a wavelength of light emitted from the LED source  1  uses a wavelength selected from analysis items. The light illuminating the measurement sample  17  is absorbed by an amount of an analyte component as mentioned above, and illuminates the photo detector  6  after stray light is removed by the second slit  5 . The light illuminating the photo detector  6  is changed into an electrical signal by the photo detector  6 , and an amount of the analyte component contained in the measurement sample  17  can be obtained by analyzing an amount of the signal. Usually, such measurement is called an absorbance measurement. 
     According to the photometer  11 , in the photometer as shown in  FIGS. 1 to 4 , by bending an optical axis by the first reflector  3  and disposing the photo detector  6  immediately after the second slit  5 , it is possible to reduce radial sizes of the thermostatic bath  12  of the photometer and reaction vessel disk  14 . Accordingly, it becomes possible to further arrange the multiple reaction vessels  13  located on the circumference of the reaction vessel disk  14  and the multiple photometers  11  in multiple rows concentrically as shown in  FIG. 7 . The processing capability can be improved without changing a size of the device or the device can be made compact without changing the processing capability. Analyses of multiple items can be simultaneously conducted by respectively changing wavelengths of the multiple photometers. 
     The example of  FIG. 5  explains the first support  2  using the optical transmission member. The first reflector  3  uses its external surface as a reflective surface. As shown in  FIG. 8 , the structure can be considered in which the first support  2  uses an opaque member, inside which a space  18  passing light therethrough is provided. This increases options of methods of manufacturing components, and cost reduction is expectable. 
     In  FIG. 5 , the photo detector  6  is disposed immediately after the second slit  5 . Stray light is easily detected when the second slit  5  and photo detector  6  are too close to one another. As shown in  FIG. 9 , it is also possible for a second reflector  3 ′ to bend an optical axis downward. 
     (Embodiment 2) 
       FIG. 10  is a diagram showing a structure of the photometer according to the present invention. The present photometer is a photometer  30  including: an LED light source  21 ; a first support  22  for transmitting or passing light emitted from the LED light source  21  therethrough; a first reflector  23  provided to the first support  22 ; a first slit  24  also provided to the first support  22 ; a second support  27  provided with the second slit  25  and photo detector  26 ; and a third support  29  connecting the first support  22  and the second support  27  between which a slot  28  is formed. The light emitting diode (LED) is exampled as the light source, but a semiconductor laser etc. can be also used. 
     The first reflector  23  has a shape of a partially cutaway parabolic mirror. An axis of the parabolic mirror is set substantially horizontally, and in parallel with a straight line connecting the centers of the first slit  24  and the second slit  25 , namely with a horizontal optical axis  31 . The LED light source  21  is disposed in a focal point of the parabolic mirror. 
     An optical axis  32  of light emitted from the LED light source  21  is set generally vertically, and bent at a right angle by the first reflector  23  to be the horizontal optical axis  31 . 
     Analysis of a test sample by the photometer  30  is conducted by attaching the photometer  30  to the thermostatic bath of the liquid analysis system. The positional relationship between the structure of the liquid analysis system near the portion to which the present photometer is attached and the present photometer is the same as that of Embodiment 1, and is thus not explained. 
     Similarly to Embodiment 1, analysis of a test sample by the photometer  30  is conducted when the photometer  30  is attached to the thermostatic bath  12 , the reaction disk  14  rotates, and the reaction vessel  13  containing the target measurement sample  17  moves to the slot  28  of the photometer  30 . 
     In the analysis, light emitted from the LED light source  21  is reflected by the first reflector  23 , an illumination area is controlled to be constant by the first slit  24 , and the light illuminates the measurement sample  17  in the reaction vessel  13 . The first reflector  23  is a parabolic mirror. The light emitted from the LED light source  21  and disposed at its focal point is reflected and bent by the first reflector  23 , and then shaped and condensed in parallel with the horizontal optical axis  31 . Strictly, since the LED light source  21  is not a perfect point source, the light emitted from a position offset from the focal point of the parabolic mirror is not completely parallel to the horizontal optical axis  31 . An amount of the light passing through both of the first slit  24  and the second slit  25  from the parabolic mirror may be condensed generally in parallel. 
     To prevent bacterial growth etc., alkali or acid liquid is usually used for the constant temperature water  16 . Therefore, the first support  22 , the first reflector  23 , the first slit  24 , the second slit  25 , and the third support  29  use glass, metal, and/or resin which are resistant to alkali and acid fluids. The LED light source  21  and the photo detector  26  are sealed to prevent the intrusion of the constant temperature water  16 . 
     The principle for measurements of samples by the liquid analysis system to which the present photometer is directed is the same as that of Embodiment 1, and thus not explained. 
     Also in the photometer  30 , radial sizes of the thermostatic bath  12  of the photometer and the reaction vessel disk  14  can be reduced relative to the photometer shown in  FIGS. 1 to 4 . Similarly to  FIG. 7 , the multiple reaction vessels  13  arranged on the circumference of the reaction vessel disk  14  can be arranged in multiple rows concentrically. The processing capability can be improved without changing the size of the device or the device can be improved without changing the processing capability. 
     In Embodiment 1, the first reflector  3  for bending an optical axis and the condensing lens  10  for condensing light may be required. In the photometer  30  of the present embodiment, the first reflector  23  operates for both condensing and reflecting light. Thus, advantageously, the number of the components is reduced, and alignment of an optical axis becomes easy. 
     In the example shown in  FIG. 10 , the first support  22  using a light transmissive member is explained. The first reflector  23  uses its outer surface as a reflection surface. Similarly to Embodiment 1, as shown in  FIG. 11 , the structure in which an opaque member is used for the first support  22  inside which a space  33  is provided to pass light can be considered. As a result, options for manufacturing the components are increased, and cost reduction is expectable. 
     The photometer  30  is advantageous in measurement of scattering light because light that illuminates samples is condensed generally in parallel, as described above. In other words, as shown in  FIG. 12 , when the measurement sample  17  in the reaction vessel  13  contains an item for measurement using scattered light, a photo detector  26  calculates the amount of scattered light  35  lost from the received transmitted light  34  which has been reduced by dispersion. At this time, it is desirable for the scattered light  35  not to enter the photo detector  26 . The scattered light  35  is illumination light emitted by a specific angular distribution. Therefore, when the photometer  11  shown in Embodiment 1 measures scattering light, light may illuminate the measurement sample  17  in the reaction vessel  13  at an angle as shown in  FIG. 13 . Therefore, the scattered light  35  enters the photo detector  26  easily. As a result, it may be difficult to conduct precise scattering light measurement. In the present photometer  30 , light illuminating samples is condensed generally in parallel. It is difficult for the scattering light to enter the photo detector  26 . This is advantageous in measurement of scattered light. 
     The photo detector  26  is disposed immediately after the second slit  25  in the  FIG. 10 . Stray light tends to be detected when the second slit  25  and the photo detector  26  are close to one another. As shown in  FIG. 14 , an optical axis can be bent downward by use of the second reflector  23 ′. In this case, the second reflector  23 ′ may not be a parabolic mirror. Further, as shown in  FIG. 15 , an image of light emitted from the LED light source  21  may be formed at a focal point of the parabolic mirror by use of a condensing lens  10 ′. 
     (Embodiment 3) 
       FIG. 16  is a diagram showing a structure of the photometer according to the present invention. The present photometer is a photometer  50  including: an LED source  41 ; a first support  42  transmitting and passing light emitted from LED source  41  therethrough; a first reflector  43  provided to the first support  42 ; a first slit  44  provided also to the first support  42 ; a second support  47  provided with a second slit  45  and a photo detector  46 ; and a third support  49  connecting the first support  42  and the second support  47  between which a slot  48  is formed. A light emitting diode (LED) is exampled as a light source, but additionally, a semiconductor laser etc. also can be used. 
     The first reflector  43  is an elliptic mirror defined to be shaped in a partially cut away elliptic mirror and to have a first focal point  51  where the LED source  41  is disposed and a second focal point  52  generally at the center in the longitudinal direction of an optical axis transmitted in the measurement sample  17  in the reaction vessel  13 . The optical axis  53  of light emitted from the LED source  41  is set generally vertically, and reflected and bent by the first reflector  43  at a right angle to be a horizontal optical axis  54 . To arrange the optical axis  53  of the light emitted from LED source  41  and the horizontal optical axis  54  passing through a sample at a right angle, a long axis of a reference ellipse may be set at 45 degrees relative to the optical axis  53  of emitted light and the horizontal optical axis  54 , and a distance between the first focal point  51  and second focal point  52  of the reference ellipse may be the same as a short axis of the reference ellipse. It is important that the optical axis is incident to an optical incidence plane of the reaction vessel  13  at a right angle. It is not necessarily important to reflect and bend the optical axis by use of the first reflector  43  at a right angle. When the optical axis is not bent at a right angle, the optical axis  53  of emitted light is not vertical. 
     Analysis of measurement samples by the present photometer  50  is conducted by attaching the photometer  50  to the thermostatic bath of the liquid analysis system. The positional relationship between the structure around the portion where the present photometer of the liquid analysis system is attached and the photometer is the same as Embodiment 1 and thus not explained. 
     Similarly to Embodiment 1, analysis of measurement samples by the present photometer  50  is conducted when the photometer  50  is attached to the thermostatic bath  12 , the reaction disk  14  rotates, and the reaction vessel  13  containing the target measurement sample  17  moves to the slot  48  of the photometer  50 . 
     In the analysis, light emitted from the LED source  41  is reflected by the first reflector  43 , and illuminates the measurement sample  17  in the reaction vessel  13  with an illumination area controlled to be constant by the first slit  44 . The first reflector  43  is an elliptic mirror. Light emitted from the LED source  41  disposed at the first focus  51  of the first reflector  43  is reflected and bent by the first reflector  43  and then condensed to a generally central position in the longitudinal direction of the optical axis transmitted in the measurement sample  17 , the generally central position being at the second focal point  52 . 
     Alkali or acid liquid is generally used for constant temperature water  16  to prevent bacterial growth etc. Therefore, the first support  42 , the first reflector  43 , the first slit  44 , the second slit  45 , and the third support  49  use glass, metal, and/or resin which are resistant to alkali and acid fluids. The LED source  41 , the photo detector  46 , etc. are sealed to prevent the intrusion of the constant temperature water  16 . 
     The principle of measurements of samples by the liquid analysis system to which the present photometer is directed is the same as that of Embodiment 1, and thus not explained. 
     Also in the present photometer  50 , radial sizes of the thermostatic bath  12  and reaction vessel disk  14  of the photometer can be reduced relative to the photometer as shown in  FIGS. 1 to 4 . Similarly to  FIG. 7 , the multiple reaction vessels  13  arranged on the circumference of the reaction vessel disk  14  can be further arranged in multiple rows concentrically. The processing capability can be improved without changing a size of the system or the system can be improved without changing the processing capability. 
     In Embodiment 1, the first reflector  3  for bending an optical axis and the condensing lens  10  for condensing light are required. In the photometer  50  of the present embodiment, the first reflector  43  operates for both condensing and reflecting light. The number of the components is reduced to advantageously achieve easy optical axis alignment. 
     In the example shown in the  FIG. 16 , the first support  42  is explained by using an optical transmissive member, and the first reflector  43  uses its external surface as a reflection surface. Similarly to Embodiment 1, as shown in  FIG. 17 , the structure can be also considered in which an opaque member is used for the first support  42  in which a space  55  is provided for passing light therethrough. Accordingly, options of manufacturing components are increased and cost reduction is expectable. 
     In the photometer  50 , as described above, light illuminating a sample is condensed to the generally central position in the longitudinal direction of an optical axis transmitted in the measurement sample  17 . Therefore, compared to Embodiments 1 and 2, disadvantage arises in measurement of scattered light, but an amount of received light detected by the photo detector  46  after passing through the first slit  44  and the second slit  45  increases compared to when the light is parallel. This is because, similarly also to Embodiment 1, when light from a light source is made parallel, it is difficult to pass light emitted offset from the light source through both the first slit and the second slit, but when light from the light source is condensed, the light emitted offset from the light source can be condensed easily compared to when the light is parallel. 
       FIG. 18  shown a rate of amounts of received light calculated by comparative simulation when the first reflector is a parabolic mirror and when the first reflector is an elliptic mirror.  FIG. 18  ( a ) shows the case of the parabolic mirror, and  FIG. 18  ( b ) shows the case of the elliptic mirror. As the result of the simulation using an amount and size of emitted light so that both cases are under the generally same condition, when an amount of received light is 1 in the case of the parabolic mirror, an amount of received light is 1.27 in the case of the elliptic mirror. It has been turned out that an amount of light in the case of the elliptic mirror is greater. 
     That is, it is suitable to condense light by use of a lens as in Embodiment 1 or by use of, e.g., an elliptic mirror as in Embodiment 3 to conduct a high sensitivity measurement requiring a large amount of light. It is suitable to condense light in parallel as in Embodiment 2 to conduct a measurement using scattered light. The lens and mirrors may be used properly depending on the usage. The photo detector  46  is disposed immediately after the second slit  45  in the  FIG. 16 . Since stray light is detected easily when the second slit  45  and photo detector  46  are too close to one another, it is also possible to bend an optical axis downward by use of the second reflector  43 ′ as shown in  FIG. 19  and  FIG. 20 . In this case, the second reflector  43 ′ may not be an elliptic mirror. Further, as shown in  FIG. 20 , an image of light emitted from the LED source  41  is formed at the first focal point  51  of the elliptic mirror by use of a condensing lens  10 ″. To reduce the influence of stray light in scattered light measurement, it is also possible to provide a third slit  56  as shown in  FIG. 21 . 
     (Embodiment 4) 
       FIG. 22  is a diagram showing a liquid analysis system  60  of the present embodiment. The liquid analysis system  60  includes: the thermostatic bath  12 ; a reaction vessel disk  14  having the multiple reaction vessels  13  on the circumference concentric with the thermostatic bath  12 ; sample containers  61  containing the measurement samples  17 ; a rack  62  carrying the multiple sample containers  61 ; a dispenser  63  for sucking the measurement sample  17  by a constant amount and dispensing the sample in the sample container  61  into the reaction vessel disks  13 ; a reagent disk  65  containing reagent bottles  64  containing multiple reagents selectable depending on analysis items; a reagent dispenser  66  for aspiring a constant amount of a reagent from the reagent bottles  64  and dispending the reagent to the reaction vessels  13 ; a stirring section  67  for stirring the measurement samples  17  and reagents dispensed to the reaction vessels  13 ; a washing section  68  for washing the reaction vessels  13  after analysis; and a measurement section  69  having one or multiple photometers of any one of Embodiments 1, 2, and 3. 
     In  FIG. 22 , the reaction vessel disk  14  stops when the measurement samples  17  are dispensed, reagents are dispensed, the measurement sample  17  and reagent dispensed to the reaction vessel  13  are stirred, and the reaction vessels  13  are washed, and rotates and moves to the next reaction vessel  13  for these operations. The rack  62  moves straight to carry the multiple sample containers  61 . The reagent disk  65  rotates and moves to a position where the reagent dispenser  66  can aspire the desired reagent bottle  64 . Usually, the reaction vessel disk  14  rotates in a certain direction. The measurement sample  17  and the reagent are dispensed. The measurement sample  17  in the reaction vessel  13  is stirred to be measurable and moves to the position of the measurement section  69 , and then measured by the desired photometer. 
     In the liquid analysis system  60 , absorption measurements and measurements oriented to scattering characteristics are mixed even in measuring absorptions. In the measurement section  69 , multiple photometers  11 , multiple photometers  30 , and multiple photometers  50  may be mixed and placed depending on purposes. Wavelengths of the multiple photometers may be varied to conduct analyses of multiple items simultaneously. 
     In this case, arrangement intervals of the arranged photometers are the same as those of the multiple reaction vessels  13  arranged to the reaction vessel disk  14 . The multiple measurement samples  17  can be measured by the multiple photometers at the same time. Complicated data processing and device control can be eased and the measurements under the same condition can be conducted. 
     Reference Signs List 
     
         
           1  . . . LED light source 
           2  . . . First support 
           3  . . . First reflector 
           3 ′ . . . Second reflector 
           4  . . . First slit 
           5  . . . Second slit 
           6  . . . Photo detector 
           7  . . . Second support 
           8  . . . Slot 
           9  . . . Third support 
           10  . . . Condensing lens 
           10 ′ . . . Condensing lens 
           11  . . . Photometer 
           12  . . . Thermostatic bath 
           13  . . . Reaction vessel 
           14  . . . Reaction vessel disk 
           15  . . . Flow path 
           16  . . . Constant temperature water 
           17  . . . Measurement sample 
           18  . . . Light transmitting space 
           21  . . . LED light source 
           22  . . . First support 
           23  . . . First reflector 
           23 ′ . . . Second reflector 
           24  . . . First slit 
           25  . . . Second slit 
           26  . . . Photo detector 
           27  . . . Second support 
           28  . . . Slot 
           29  . . . Third support 
           30  . . . Photometer 
           31  . . . Horizontal optical axis 
           32  . . . Optical axis of emitted light 
           33  . . . Light transmitting space 
           34  . . . Transmitted light 
           35  . . . Scattered light 
           41  . . . LED light source 
           42  . . . First support 
           43  . . . First reflector 
           43 ′ . . . Second reflector 
           44  . . . First slit 
           45  . . . Second slit 
           46  . . . Photo detector 
           47  . . . Second support 
           48  . . . Slot 
           49  . . . Third support 
           50  . . . Photometer 
           51  . . . First focal point 
           52  . . . Second focal point 
           53  . . . Optical axis of emitted light 
           54  . . . Optical axis on horizontal portion 
           55  . . . Light transmitting space 
           56  . . . Third slit 
           60  . . . . Liquid analysis system 
           61  . . . Sample container 
           62  . . . Rack 
           63  . . . Dispenser 
           64  . . . Reagent bottle 
           65  . . . Reagent disk 
           66  . . . Reagent dispenser 
           67  . . . Stirring section 
           68  . . . Washing section 
           69  . . . Measurement section