CN201014977Y - Optical path device for clinical inspection analytical instrument - Google Patents

Abstract

The utility model relates to an optical path device for a medical examination and analysis instrument, in particular to a miniature monochromator used as the optical splitting system of a medical examination and analysis instrument. The utility model comprises an optical source module radiating a continuous spectrum, a filter module used to filter parasitic light and secondary diffraction spectrum, a miniature monochromater with a continuously adjustable wave length, a thermostat module and a photoelectric receiving module. The utility model is characterized in that the optical source module emits a composite spectrum, the filter module filters irrelevant spectrum out of the composite spectrum, the filtered spectrum then focuses on the inlet seam of the miniature monochromator, the miniature monochromator then emits the desired monochromatic light from the outlet seam, and the monochromatic light passes the thermostat module to carry out the color comparison, and is finally received by the photoelectric receiving module. Compared to the prior art, the entire optical path device of the utility model is divided into a plurality of modules, and each module adopts the component-type design to facilitate the installation and troubleshooting by the troubleshooting personnel.

Description

Light path device of clinical examination analytical instrument

Technical Field

The utility model relates to a light path device of medical examination analytical instrument, in particular to a medical examination analytical instrument which is a micro monochromator as a light splitting system of the medical examination analytical instrument.

Technical Field

Optical analysis is one of the most commonly used detection methods in clinical medical examination and analysis, among which, the photoelectric colorimetry and the spectrophotometry are the most prominent, and has been widely used in various medical analysis instruments, such as biochemical analyzers, enzyme-linked immunosorbent assays, hemagglutination, and drug sensitive devices. Colorimetric and spectrophotometric methods are analytical methods established based on the selective absorption of electromagnetic radiation by the peculiarities of different molecular structures. This analysis method is carried out on the premise that the desired wavelength of radiation, i.e. monochromatic light, is produced. There are various methods for generating monochromatic light, and according to different precision requirements and application occasions, the current realization technologies are as follows: the LED monochromatic light source, the interference filter light splitting technology, the prism light splitting technology and the grating light splitting technology, wherein the interference filter light splitting technology and the grating light splitting technology can realize higher monochromatic light precision, namely the spectral bandwidth can be less than 12nm, so the two technologies completely meet the requirements of clinical examination instruments. In clinical testers, such as biochemical analyzers and enzyme-labeled analyzers, most use interference filter spectroscopy to produce monochromatic wavelengths. The optical path has simple structure and is suitable for various small-sized inspection and analysis instruments. However, this has the disadvantage that the interference filter has a short lifetime and needs to be replaced frequently. In addition, the number of monochromatic light wavelengths is limited, and one filter corresponds to one wavelength, and in most cases, only 8 filters, and at most 12 filters, can be mounted. For the occasion of special wavelength requirement, the corresponding wavelength is needed to be added. A light splitting system using a grating light splitting technology, generally referred to as a monochromator, can realize continuous wavelength adjustment, that is, wavelength selection of 1nm stepping can be realized in a spectrum range. In addition, the monochromator is closed, is not easy to be affected with damp, and has a service life of more than 2 years.

Grating spectroscopy, a mature technique, has been widely used in large high-precision spectrophotometers, but has relatively few applications in conventional medical test equipment. In recent years, designers have begun considering applying this technique to conventional medical examination instruments. On a spectrophotometer, two optical path structures, namely a Cerny-Turner optical path structure and a Fasatie-Ebert optical path structure, can be frequently seen. The Cerny-Turner optical path structure collimates and focuses the beam by two separate concave mirrors. In the fast-Ebert optical path structure, the two concave reflectors are combined into one piece, and the collimation and focusing functions are achieved simultaneously. The Cerny-Turner optical path structure is suitable for occasions with strict requirements on wavelength accuracy and aberration. The fast-Ebert optical path structure can also be used in the situation of higher wavelength accuracy, but the aberration is larger. For conventional clinical laboratory instruments, wavelength bandwidths of less than 12nm are permissible and large aberrations are permissible, so the Fastie-Ebert optical path structure is more suitable for small instruments, such as biochemical analyzers.

In the domestic market, a few manufacturers producing clinical inspection instruments use grating light path structures for light splitting. In order to reduce the optical path structure and simplify the optical path device, concave reflection gratings are adopted, but because the groove density of the concave reflection gratings is small and is generally below 1200L/mm, and because the spectral bandwidth is required to be less than 12nm, the focal length matched with the groove density of 1200L/mm must be more than 90mm, so the finally realized optical path structure has larger size, and the shape of the final instrument is large. In addition, the manufacturing reject ratio of the concave surface reflection grating is high, which causes the cost of the concave surface grating to be high. The light splitting is realized by adopting a planar reflection grating, which is a common grating light splitting mode and needs the matching of a concave reflecting mirror. The manufacturing process is relatively simple, and the passing rate is high.

For the grating light splitting mode with continuously adjustable wavelength, according to the grating equation,

a sinusoidal mechanism is required to achieve the sinusoidal variation of the above equation. The sinusoidal variation is the sinusoidal variation of the wavelength and the grating rotation angle, and a precise transmission mechanical structure is generally adopted to realize the function. But in implementation, there are differences. Most of the devices are added with structures, the screw rod nut is limited on the horizontal plane to ensure that the screw rod nut moves stably, and in addition, the difference is large when the origin position of the precise transmission mechanism is detected. The utility model discloses in, then utilize current structure to realize spacing on screw-nut's the horizontal plane. In addition, in some light path devices, the wavelength accuracy is ensured by detecting the original point position of the screw rod nut and the external stepping motor, and the wavelength accuracy is ensured by detecting the original points of the grating turntable and the stepping motor, so that the detection reliability is improved.

The debugging of the monochromator is quite cumbersome, including the debugging of the individual lens spots, the debugging of wavelength accuracy and the debugging of the position of the origin. Each step of debugging is completed by related tools, and a debugging person is required to have certain professional skill. With the increasing demand for clinical inspection instruments using grating for light splitting, the debugging personnel is required to complete a certain amount of light path debugging within a specified time. Therefore, in the design of the whole optical path device, including the structural design of the micro monochromator, it needs to fully consider how to reduce the debugging workload and improve the debugging speed.

In order to overcome the not enough of prior art, the utility model discloses in, adopt modularization and a whole set of light path device of subassembly formal design, a whole set of light path device falls into several modules promptly, adopts the design of subassembly formal in the module, makes things convenient for debugging personnel to assemble and debug.

Disclosure of Invention

The purpose of the utility model is realized through the following technical scheme: the utility model discloses contain the continuous spectrum's of radiation light source module, be used for eliminating parasitic light and second grade diffraction spectrum's color filter module, wavelength continuously adjustable's miniature monochromator, thermostatic bath module, photoelectric receiving module, its characterized in that light source module jets out the compound light, process the irrelevant spectrum is filtered out to the color filter module, focuses on the income seam of miniature monochromator, follow required monochromatic light is jetted out to the play seam of miniature monochromator, and monochromatic light process the thermostatic bath module carries out the color comparison, at last by photoelectric receiving module receives.

The light splitting of light path device is realized to miniature monochromator, in the miniature monochromator light path structure, adopt fast-Ebert light path structure, fast-Ebert light path structure needs to contain a plane reflection grating and a relatively great spherical reflector of overall dimension. The micro monochromator comprises a spherical reflector, a reflection grating, two plane reflectors and a group of precise transmission mechanisms for driving the reflection grating to rotate, wherein the two plane reflectors are used for changing the light direction and optimizing the structural layout of the light path. In the precise transmission mechanism of the micro monochromator, a stepping motor, a precise screw rod, a special sliding block, a special sine arm, an extension spring and a grating rotary table are adopted to realize the proportional relation between the rotation angle of the stepping motor and the required monochromatic wavelength. In the micro monochromator, a double-optical-coupling origin detection mode is adopted to detect the origin positions of the grating turntable and the external stepping motor, so that the wavelength accuracy and the repeatability of the micro monochromator are improved. And a sensor is arranged in the micro monochromator to detect the origin position of the grating rotary table instead of the origin position of the screw nut, so that the origin position of the precise transmission mechanism is roughly detected. And a sensor is added outside the micro monochromator, and the origin position of the transmission mechanism is accurately detected by detecting the rotation angle of the stepping motor. The wavelength accuracy of the micro monochromator is improved by the matching detection of the internal sensor and the external sensor. Because the micro monochromator is closed, the internal sensor is not easy to be influenced by external human factors to generate position deviation, thereby causing wavelength deviation. In addition, the internal sensor has certain accuracy, so that the position of the external sensor can be debugged through the internal sensor only by matching with special software control, and the debugging of the external sensor is facilitated. Therefore, compared with the prior art, the micro monochromator of the utility model has the characteristics of high precision, strong reliability, good maintainability and the like.

The sliding block of the utility model is characterized in that the sliding block is provided with a hole with the diameter of 6.0 mm; the sine arm is a threaded rod with a phi 6.0mm spheroid characteristic at the front end. The phi 6.0mm hole is required to be in clearance fit with the phi 6.0mm spheroid, and the fit clearance is not more than 0.1mm. The sine arm is screwed into the grating rotary table, and the wavelength accuracy of the micro monochromator can be adjusted through the screwing depth of the sine arm into the grating rotary table. The rotation of the grating turntable can be accomplished by standard steel balls or bearings.

The utility model discloses among the light source module, contain light source fine setting mechanical structure, focusing lens, the continuous spectrum's of a radiation light source and chopper. The light source fine-tuning mechanical structure can be used for fine-tuning the position of the light source in the light path, and ensuring that the radiated energy of the light source can be focused on the inlet seam of the micro monochromator through the focusing lens to the maximum extent.

The color filter module needs to contain a color filter glass selection mechanism and colored glass. The color filter glass selection mechanism comprises an electromagnet and a seat for assembling colored glass, and the correct colored glass is placed in the light path by controlling the on and off states of the electromagnet so as to eliminate the influence of stray light or secondary diffraction spectrum. In the colored glass, three kinds of colored glass, namely ultraviolet transmitting visible absorption glass, bluish blue glass, golden yellow glass and the like are selected for eliminating the influence of stray light and second-order diffraction light and balancing light energy with wavelengths in a spectrum area.

The constant temperature bath module is used for assembling the sample cell and keeping the constant temperature of the sample. The cuvette may comprise a flow cell and a cuvette. In the constant temperature bath module, two phi 3.0mm small steel balls are adopted, and when the cuvette is plugged, a damping effect is achieved, and the cuvette is prevented from loosening during testing.

Compared with the prior art, the utility model have a whole set of light path device and fall into several modules, adopt the design of subassembly form in the module, make things convenient for advantages such as debugging personnel's assembly and debugging.

Brief description of the drawings

FIG. 1 is a diagram of an optical path apparatus of the present invention, which is divided into 5 modules

Figure 2 is a block diagram of the light source module of the present invention,

FIG. 3 is a block diagram of a color filter module according to the present invention

FIG. 4 is an exploded view of the micro monochromator of the present invention

FIG. 5 is a schematic view of the interior of the micro monochromator of the present invention

FIG. 6 is an optical schematic diagram of the micro monochromator of the present invention

Fig. 7 is a schematic view of the screw rod assembly of the present invention

FIG. 8 is a schematic view of the grating turntable assembly of the present invention

FIG. 9 is a diagram of the assembly relationship between the micro monochromator and the peripheral parts of the present invention

FIG. 10 is a block diagram of the thermostatic bath of the present invention

FIG. 11 shows a thermostatic bath of the present invention

Detailed Description

The present invention will be described in detail with reference to the drawings.

The utility model relates to a novel, adopted miniature monochromator to realize the clinical examination analytical instrument light path device of beam split. It comprises a light source module 1, a color filter module 2, a micro monochromator 3, a thermostat module 4 and a receiving module 5. As shown in fig. 1, a bundle of composite light is emitted from a light source module 1, the composite light is modulated into a regular, fast and continuous on-off light beam by a chopper in the light source module 1, the light beam passes through a color filter module 2, irrelevant spectrums are filtered out, and the light beam becomes a bundle of composite light with a narrow spectrum range, and is finally focused to an entrance slit of a micro monochromator 3. The light splitting system structure of the micro monochromator 3 adopts a fast-Ebert light path structure. The composite light entering the monochromator passes through the light splitting system, and finally the required monochromatic light is emitted from the exit slit of the micro monochromator 3. The monochromatic light is subjected to color comparison through the constant temperature bath module 4 and is finally received by the photoelectric receiving module 5. The composition and function of each module will be described in more detail below.

As shown in fig. 2, the light source module 1 includes a lamp 6, a dc micro-motor 7, a light chopper 8, a condenser 9, a light source base 10, a compression spring 11, a base adjusting nut 12, and a light source fixing plate 13. The bulb 6 radiates a continuous spectrum all around. A portion of the continuous spectrum is focused into a converging beam by a condenser lens 9. The light chopper is positioned behind the condenser lens and modulates the converged light beam into a continuous and fast on-off light beam. This beam is finally focused at the entrance slit of the micro-monochromator 3. In fig. 2, the guide rail on the light source base 10 can ensure that the light source base 10 can move freely on the light source fixing plate 13 in a small horizontal direction. The position of the light source base is finely adjusted by the compression spring 11 and the base adjusting nut 12, so that the filament of the bulb 6 is positioned on the optical axis of the condenser 9, and as much light energy as possible enters the micro monochromator 3.

Due to the grating light splitting self-factor, for example, the influence of second-order diffraction spectrum exists and the background optical length is difficult to reach 10 ^-6 Therefore, the utility model discloses in increased filter module 2, firstly eliminate the influence of visible light under the near ultraviolet wave band, secondly eliminate the influence of second order diffraction spectrum, thirdly balance the light energy between the monochromatic wavelength to a certain extent. In FIG. 3, the color filter module includes an electromagnet 14, which transmits ultraviolet lightVisible absorption glass 15, color filter glass base 16, golden glass 17And cyan glass 18. The golden glass 17 and the cyan glass 18 are stacked and fitted in the filter glass holder 16. By controlling the on-off of the electromagnet 14, ultraviolet transmitting visible absorption glass 15 or golden yellow glass 17 and blue glass 18 can be freely selected to be arranged in the light path. A filter glass mount 16 abuts the micro-monochromator 3.

The micro monochromator is used as the core component of the utility model, which is a pocket-sized optical instrument with a precise transmission mechanism. For convenience of description, we divide the micro-monochromator 3 into: a lead screw assembly 19, a left side plate assembly 20, a raster turret assembly 21 and a right side plate assembly 22, as shown in the exploded view of the micro-monochromator of fig. 4. As shown in the internal schematic diagram of the micro-monochromator of FIG. 5, when the screw 23 is rotated, the slider 24 is driven to move horizontally. As the spherical end of the sine arm 25 is in contact fit with the phi 6.0mm hole of the sliding block 24, the horizontal movement of the sliding block 24 drives the spherical end of the sine arm 25 to slide in the phi 6.0mm inner groove, so that the grating rotary table component 21 is pushed to rotate, and the sine change of the moving distance of the sliding block and the grating rotating angle is realized. According to the equation of the grating,

the monochromatic wavelength lambda and the grating rotation angle (alpha + beta) are in a sinusoidal relationship, so that the stepping motor 44 controls the lead screw to drive the grating turntable to rotate, and the required target wavelength can be obtained. Based on the grating equation, the utility model adopts the fast-Ebert optical path structure, as shown in fig. 6. The composite light from the light source module 1 is focused to the entrance slit 26, reflected by the plane mirror 27 and incident to the spherical mirror 28, at this time, the spherical mirror 28 changes the traveling direction of the incident beam and collimates the incident beam to the plane reflection grating 29, and the plane reflection grating 29 is positioned at a specific angle (α + β) by controlling the rotation of the lead screw 23, so that a specific monochromatic wavelength is diffracted in the β direction. The specific monochromatic wavelength is directed in parallel to the other half of the spherical mirror 28, through the plane mirror 27 and finally out of the micro monochromator 3 through the slit 30.

The operation principle of the micro monochromator 3 is roughly described above, and the implementation of the micro monochromator 3, i.e. the precise transmission mechanism for driving the plane reflection grating 29 to rotate, will be described in detail below. It is a big bright spot of the utility model. The utility model discloses an among the accurate drive mechanism, adopt accurate lead screw, special slider, special sine arm and grating revolving stage, drive the rotation of planar reflection grating 29. As shown in fig. 7, a schematic view of the screw assembly 19. The special slide 24 is a special structure drilled with a 6.0mm diameter hole for cooperation with the sine arm 25. The slide block 24 is locked on the nut of the screw rod 23, and the right stopper 31 and the left stopper 32 limit the moving range of the nut of the screw rod 23 and prevent the grating rotary table assembly 21 from being damaged. The lead screw assembly 19 is assembled to the left and right side plate assemblies 20 and 22. The concentricity of the screw rod assembly 19 can be kept by slightly adjusting the position of the screw rod adjusting seat 39, and the screw rod assembly 19 is convenient to disassemble and assemble.

As shown in the schematic view of the raster turret assembly 21 of fig. 8. The small bearing 37 and the large bearing 33 are respectively assembled on the upper part and the lower part of the grating rotary table 34; the plane reflection grating 29 is adhered to the grating rotary table 34; the sine arm 25 is screwed into the grating turntable 34; a spring seat is provided intermediate the two retaining nuts 36. The sinusoidal arm 25 has a spherical body at one end, which is fitted with the slider 24. The sphere with the diameter of 6.0mm of the sine arm 25 is matched with the hole with the diameter of 6.0mm of the slide block 24, and the matching clearance is less than 0.1mm. The other end of the sine arm 25 is pulled by the tension spring 46, the ball of the sine arm 25 is tightly attached to the inner wall of the hole of the slide block 24, when the screw rod rotates in the opposite direction, the ball of the sine arm 25 is always tightly attached to the inner arm of the slide block 24, and therefore the backward clearance is not generated to influence the wavelength accuracy.

In addition, a segment 35 is provided on the grating turntable for marking the starting position of the grating turntable, i.e., the starting position of the precision transmission mechanism. The position sensor 40 mounted in the right side plate assembly 22 detects the position of the sector 35, i.e., the origin position. Since the dispersion angle of the plane reflection grating 29 is about 0.07 °/nm, i.e., 14.3nm/1 °, if the accuracy of ± 2nm wavelength is to be satisfied, the angle accuracy of the position sensor 40 for detecting the sector 35 needs to be within ± 0.14 °, but it is difficult to realize this accuracy for a general sensor, i.e., a photocoupler. In order to improve the detection accuracy of the origin position, a sensor is arranged outside the monochromator. As shown in fig. 9, a synchronizing wheel 42 is mounted on a coupling 43, and a light-passing groove with a width of 1mm is formed on a disc of the synchronizing wheel 42. Meanwhile, an angle sensor 41 is mounted on a side plate 45 to which a stepping motor 44 is fixed, and a light-passing groove of a synchronizing wheel 42 is detected by the angle sensor 41. The width of the light-transmitting groove of the synchronizing wheel 42 is 1mm, and the rotating precision of the screw rod 23 is +/-3 degrees. As the screw 23 rotates once, the wavelength generated by the micro-monochromator 3 is about 46nm, and the conversion synchronous wheel 42 rotates 1 degree to generate 0.128nm. Therefore, the detection by the angle sensor 41 can achieve the detection accuracy of +/-0.4 nm. The precision can meet the requirements of clinical inspection instruments, namely the wavelength precision is +/-2 nm, and the repeatability is less than 1.5nm. In a word, the internal position sensor 40 of the micro monochromator 3 roughly detects the position of the origin, the precision error is controlled within +/-4 nm, and then the external angle sensor 41 of the micro monochromator 3 accurately detects the position, and the precision error is reduced to +/-0.4 nm from +/-4 nm.

Fig. 10 is an assembly view of the thermostatic bath module 4, which contains a fan 47, a heat sink 48, a peltier 49, a thermostatic bath 50, thermostatic bath cover cotton 51, heat insulating cotton 52, and a temperature sensor 53. The peltier 49 is fitted between the thermostatic bath 50 and the heat sink 48. The constant temperature bath 50 is constantly controlled to be heated or cooled by the control of the peltier 49 and the temperature sensor 53. The heat sink 48 and the fan 47 dissipate the excess heat. Two balls 55 with the diameter of 3.0mm are assembled in the thermostatic bath 50 to play a role in damping. The through holes at the left and right sides of the thermostatic bath 50 are in a conical shape, and the clear aperture phi is 2.5mm.

In addition, a receiving module mounting 54 is provided on the thermostatic bath module for mounting the receiving module 5.

The photoelectric receiving device in the receiving module 5 adopts an ultraviolet enhanced silicon photodiode, and the spectral response range is 190-900 nm.

Claims (17)

1. An optical path device of a clinical examination analytical instrument comprises a light source module for radiating continuous spectrum, a color filter module for eliminating stray light and secondary diffraction spectrum, a micro monochromator with continuously adjustable wavelength, a constant temperature bath module and a photoelectric receiving module, and is characterized in that the light source module emits composite light, irrelevant light spectrum is filtered by the color filter module, the composite light is focused to an entrance slit of the micro monochromator, required monochromatic light is emitted from the exit slit of the micro monochromator, and the monochromatic light is subjected to color comparison by the constant temperature bath module and finally received by the photoelectric receiving module.

2. The optical circuit apparatus for clinical laboratory analysis instrument according to claim 1, wherein said micro monochromator is used for splitting light of said optical circuit apparatus, and said optical circuit structure of said micro monochromator is a fast-Ebert optical circuit structure, and said fast-Ebert optical circuit structure comprises a plane reflection grating and a spherical mirror with relatively large external dimension.

3. The optical circuit apparatus for clinical laboratory analysis instrument according to claim 2, wherein said optical circuit structure layout is optimized by using two pieces of said plane mirror to change the light direction in said micro monochromator structure.

4. The optical path apparatus for clinical examination analyzer according to claim 3, wherein the micro monochromator comprises a spherical mirror, a reflective grating and a set of precise transmission mechanisms for driving the reflective grating to rotate.

5. The optical path apparatus of clinical examination analyzer according to claim 4, wherein the precise transmission mechanism of the micro monochromator comprises a stepping motor, a precise screw rod, a special slider, a special sine arm, an extension spring and a grating turntable, so as to realize the proportional relationship between the rotation angle of the stepping motor and the required monochromatic wavelength.

6. The optical path apparatus for clinical laboratory analyzing instrument according to claim 5, wherein in the fine actuator of said micro-monochromator, a position sensor is provided for roughly detecting the position of the origin of said fine actuator.

7. The optical path apparatus for clinical examination analyzer according to claim 5, wherein an angle sensor is added outside the micro-monochromator for precisely detecting the origin position of the precision driving mechanism.

8. The optical circuit apparatus of clinical examination analysis instrument according to claim 5, characterized in that said slider has a feature of one 6.0mm hole; the sine arm is a threaded bar with a phi 6.0mm spheroid characteristic at the front end. The phi 6.0mm hole is required to be in clearance fit with the phi 6.0mm spheroid, and the fit clearance is not more than 0.1mm.

9. The optical circuit apparatus of clinical laboratory analyzer according to claim 5 or 8, wherein said sine arm is screwed into said grating rotary table, and the wavelength accuracy of said micro monochromator can be adjusted by the depth of screwing said sine arm into said grating rotary table.

10. The optical circuit device of clinical examination and analysis instrument according to claim 5, wherein the rotation of grating rotary table can be completed by standard steel ball or bearing.

11. The optical circuit apparatus of claim 1, wherein the light source module comprises a light source trimming mechanism, a focusing lens, a light source for emitting a continuous spectrum of light, and a chopper.

12. The optical circuit apparatus of claim 11, wherein the light source fine-tuning mechanism is configured to fine-tune the position of the light source in the optical circuit to ensure that the energy radiated from the light source is focused on the slit of the micro-monochromator through the focusing lens to the maximum extent.

13. The optical path apparatus for clinical laboratory analysis instrument according to claim 1, wherein said color filter module comprises a color filter glass selection mechanism and a color glass.

14. The optical path apparatus for clinical laboratory analysis instruments according to claim 13, wherein said color filter glass selecting mechanism comprises an electromagnet and a holder for mounting a colored glass, and the correct colored glass is placed in the optical path by controlling both on and off states of said electromagnet to eliminate the influence of stray light or secondary diffraction spectrum.

15. The optical path device for clinical laboratory test analysis instrument according to claim 14, wherein said colored glass is selected from three kinds of colored glass, i.e. uv transparent visible absorption glass, blue glass and golden glass, for eliminating the influence of stray light and second order diffracted light and balancing the light energy between wavelengths in the spectral region.

16. The optical path apparatus for clinical laboratory analysis instrument according to claim 1, wherein said thermostatic bath module is used for assembling a sample cuvette and keeping a constant temperature of a sample. The cuvette may comprise a flow cell and a cuvette.

17. The optical circuit apparatus for clinical laboratory analyzer according to claim 16, wherein said thermostatic bath module comprises two small steel balls with a diameter of 3.0mm, which can provide damping effect when said cuvette is inserted into or removed from said thermostatic bath module, thereby preventing looseness of said cuvette during testing.

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