An assembly for measurements of one or more optical parameters of a sample medium and a method for measuring one or more optical parameters of a sample medium using an assembly

Abstract

The disclosure relates to an assembly (1) for measurements of one or more optical parameters of a sample medium, the assembly comprising a light source (11); a light sheet generator (12) configured to receive light from the light source (11) and to provide a light sheet (13) extending in a first spatial direction (101), wherein the light sheet (13) has a propagation path in a second spatial direction (102); a holder (15) for a sample (16) of the medium, configured to enable the light sheet (13) to illuminate the sample (16); an optical sensor (17) with a sensor surface (18) comprising an array of pixels extending in the first spatial direction (101) so as to receive the light sheet when transmitted through the sample (16) in the second spatial direction (102); a control unit (18) with a memory, wherein the control unit (18) is arranged to control the light source (11) and the optical sensor (17); wherein the sensor surface (18) of the optical sensor (17) further extends in a third spatial direction (103), the third spatial direction being perpendicular to the first direction and the second direction, to form a one-dimensional sensor surface for receiving and recording the light sheet (13) after the light sheet (13) has passed through the sample (16). The disclosure further relates to a method for measuring one or more optical parameters of a sample medium using an assembly.

Description

[0001] AN ASSEMBLY FOR MEASUREMENTS OF ONE OR MORE OPTICAL PARAMETERS OF A SAMPLE MEDIUM AND A METHOD FOR MEASURING ONE OR MORE OPTICAL PARAMETERS OF A SAMPLE MEDIUM USING AN ASSEMBLY

[0002] Technical field

[0003] The present disclosure relates to an assembly for measurements of one or more optical parameters of a sample medium and a method for measuring one or more optical parameters of a sample medium using an assembly. More specifically, the disclosure relates to an assembly for measurements of one or more optical parameters of a sample medium and a method for measuring one or more optical parameters of a sample medium using an assembly as defined in the introductory parts of the independent claims.

[0004] Background art

[0005] Spectrophotometry is the technique of measuring how light interacts with, and is attenuated in a sample. Conventionally, such measurement instruments fall into two general categories: instruments with continuous light sources in a broadband wavelength range, and instruments with discreet wavelengths. The analysis method using discreet wavelengths is known as colorimetry or photometry (further collectively called colorimetry) and is used to test and analyze samples by measuring how light is attenuated in a sample. These devices or assemblies are used to measure one or more optical parameters of a sample medium. The basic components of a colorimeter are (but are not limited to) a light source, a wavelength selector if the light source is broadband (usually in the form of a number of filters), a sample container (usually a cuvette), a photodetector (to detect the amount of light passed through the sample), and a display (to indicate the result of the colorimetric analysis).

[0006] A problem with these colorimeters is that the photodetector such as a sensor have a narrow detection or sensing area. The relatively smaller sensing area and variation in shape of the sample container (usually for round cuvettes) induces position errors of the optical interfaces. The positional error thus induces a wrong reading and subsequently a wrong analysis.

[0007] There is thus a need for improved spectrophotometry and colorimetry for measurements of one or more optical parameters of a sample medium. It is an object of the present disclosure to mitigate, alleviate or eliminate one or more of the above-identified deficiencies and disadvantages in the prior art and solve at least the above mentioned problem. According to a first aspect there is provided an assembly for measurements of one or more optical parameters of a sample medium, the assembly comprising a light source, a light sheet generator configured to receive light from the light source and to provide a light sheet extending in a first spatial direction, wherein the light sheet has a propagation path in a second spatial direction, the assembly further comprises a holder for a sample of the medium, configured to enable the light sheet to illuminate the sample, an optical sensor with a sensor surface comprising an array of pixels extending in the first spatial direction so as to receive the light sheet when transmitted through the sample in the second spatial direction, a control unit with a memory, wherein the control unit is arranged to control the light source and the optical sensor, wherein the sensor surface of the optical sensor further extends in a third spatial direction, the third spatial direction being perpendicular to the first direction and the second direction, to form a one-dimensional sensor surface for receiving and recording the light sheet after the light sheet has passed through the sample. The light sheet generator may include a wavelength component selector.

[0008] The sensor surface extending in the third spatial direction allows a wider sensing surface, the wider sensor surface allows a bigger sensing area thus allowing the sensor to receive and record the light sheet with high precision. Further, assembly is able to receive and record the light sheet irrespective of the shape and profile of the holder. All signal of the sheet intended to measure is thus collected irrespectively of irregularities in the sample holder or sample.

[0009] According to some embodiments, the sensor surface has an extension in the third spatial direction that is longer than W, where W is described according to the relationship W = s +2* AD; where s is the width of the light sheet before reaching the sample and AD is the maximum possible displacement of the light sheet from the central axis. By having an extension in the third spatial direction that is longer than W it made sure that the benefits of collecting all of the light sheet are realized.

[0010] According to some embodiments, the sample holder is a cuvette.

[0011] According to some embodiments, the cuvette is cylindrical with an elliptical cross section. According to some embodiments, the cuvette is cylindrical with a rectangular cross section.

[0012] According to some embodiments, the optical sensor is a one-dimensional CMOS sensor.

[0013] The CMOS sensor is able capture high-quality images in small spaces and at different angles, therefore allowing to produce high efficiency readings.

[0014] According to some embodiments, the optical sensor is a one-dimensional CCD- detector.

[0015] The CCD-detector due to its high sensitivity, dynamic range and linearity are able to obtain a high quantum efficiency.

[0016] According to some embodiments, the optical sensor is a two-dimensional CCD- detector.

[0017] According to some embodiments, the assembly further comprises a light intensity modulator configured to provide an intensity modulated light sheet by applying to the light sheet an intensity modulation having a periodical, or substantially periodical, pattern in the first spatial direction.

[0018] According to some embodiments, the light intensity modulator comprises a Ronchi grating for applying to the light sheet an intensity modulation having a periodical, or substantially periodical, pattern in the first spatial direction.

[0019] The Ronchi gratings produces a precisely patterned light source by reflection or illumination, or a stop pattern by transmission, with precise uniformity, spatial frequency, sharp edge definition, and high contrast ratio.

[0020] According to a second aspect there is provided a method for measuring one or more optical parameters of a sample medium using an assembly according to the first aspect, the method comprising: generating a light sheet at the light sheet generator, wherein the light sheet has a propagation path in a second spatial direction, illuminating the sample of the medium with the light sheet, recording at the optical sensor the light sheet after it has passed through the sample.

[0021] According to some embodiments, the method comprises mapping the attenuation through the sample along the first spatial direction of sensor. Effects and features of the second aspect are to a large extent analogous to those described above in connection with the first aspect. Embodiments mentioned in relation to the first aspect are largely compatible with the second aspect.

[0022] The present disclosure will become apparent from the detailed description given below. The detailed description and specific examples disclose preferred embodiments of the disclosure by way of illustration only. Those skilled in the art understand from guidance in the detailed description that changes and modifications may be made within the scope of the disclosure.

[0023] Hence, it is to be understood that the herein disclosed disclosure is not limited to the particular component parts of the device described or steps of the methods described since such device and method may vary. It is also to be understood that the terminology used herein is for purpose of describing particular embodiments only, and is not intended to be limiting. It should be noted that, as used in the specification and the appended claim, the articles "a", "an", "the", and "said" are intended to mean that there are one or more of the elements unless the context explicitly dictates otherwise. Thus, for example, reference to "a unit" or "the unit" may include several devices, and the like. Furthermore, the words "comprising", "including", "containing" and similar wordings does not exclude other elements or steps.

[0024] Brief of the

[0025] The above objects, as well as additional objects, features and advantages of the present disclosure, will be more fully appreciated by reference to the following illustrative and non-limiting detailed description of example embodiments of the present disclosure, when taken in conjunction with the accompanying drawings.

[0026] Figure 1 shows a perspective view of a colorimeter, according to prior art disclosure.

[0027] Figure 2 shows a perspective view of a colorimeter, according to an embodiment of the present disclosure.

[0028] Figure 3 shows a top view of the light receiving and recording by a sensor, according to an embodiment of the present disclosure.

[0029] Figure 4 shows a method of measuring one or more optical parameters of a sample medium, according to an embodiment of the present disclosure. Detailed description

[0030] The present disclosure will now be described with reference to the accompanying drawings, in which preferred example embodiments of the disclosure are shown. The disclosure may, however, be embodied in other forms and should not be construed as limited to the herein disclosed embodiments. The disclosed embodiments are provided to fully convey the scope of the disclosure to the skilled person.

[0031] Figure 1 shows a colorimeter 100 according to prior art disclosures. The colorimeter 100 includes a light source 110 that produces a polychromatic light. The polychromatic light is passed through an aperture 120 to form a beam of light that when passed through a dispersive element 150 is separated into its wavelength components. The light is further passed through an aperture 130 to select a wavelength range of interest to pass through the sample 140. The light passing through the sample is received and recorded by a sensor 160. The recorded light sheet may then be received by a sensor to perform suitable analysis.

[0032] Figure 2 shows a colorimeter according to a first aspect of the present invention. The first aspect of the disclosure shows an assembly 1 for measuring one or more optical parameters of a sample medium. The assembly 1 as shown in Figure 2 comprises a light source 11. The light source according an aspect of the present disclosure may be a solid state light source such as LEDs or LASER light source, other similar light sources can be used alternatively. Further, the assembly comprises a light sheet generator 12 that is configured to receive light from the light source 11, shape it into a light sheet 13 that extends in the first spatial dimension and select the wavelength range to be used. The light sheet then passes an optional light sheet modulator 14. According to an aspect of the present disclosure, the light sheet 13 has a propagation path in a second spatial direction 102. In addition, a holder 15 is provided for holding a sample 16 of the medium. The holder is provided such that it is configured to enable the light sheet to illuminate the sample 16. The assembly 1 further comprises an optical sensor 17 with a sensor surface 18 comprising an array of pixels extending in the first spatial direction 101. The sensor surface 18 is configured to receive the light sheet when transmitted through the sample 16 in the second spatial direction 102.

[0033] In an aspect of the present disclosure, the assembly further comprises, a control unit (not shown) with a memory. The control unit is arranged to control the light source 11 and the optical sensor 16. Further, the sensor surface 18 of the optical sensor 16 extends in a third spatial direction 103. As shown in the Figure 2, the third spatial direction is perpendicular to the first spatial direction and the second spatial direction. The surface provided in the third spatial direction allows to form a one-dimensional sensor surface for receiving and recording an image of the light sheet 13 after the light sheet 13 has passed through the sample 16.

[0034] Figure 3 shows a schematics showing the propagation of light through the holder 15 and sample 16 to be received by the sensor surface 18 of the sensor 17. The defect in surface irregularities or imperfect shape of holder translates to a displacement of the sample holder. According to the aspects of the present disclosure, the sensor surface 18 has an extension in the third spatial direction 103 that is longer than W, where W is described according to the relationship W = s +2* AD, where s is the width of the light sheet 13 before reaching the sample and AD is the maximum possible displacement of the light sheet 13 from the central axis due to defect on the sample holder. Accordingly, W, s and AD are all distances extending in the third spatial direction (103). The dashed lines in the center of the enlargement of the sensor represent the sensor surface of a prior art sensor. As illustrated in the figures by the multiple lines of possible incoming light propagation paths, many of the paths are deviated too much to be received by the prior art sensor. However, the sensor according to the present embodiment having an extension in the third spatial direction 103 that is longer than W will be able to record also light deviated due to imperfections in the cuvette surfaces.

[0035] According to an aspect of the present invention, the sample holder is a cuvette that may have a cylindrical shape with an elliptical cross section or a cylindrical shape with a rectangular cross section. However, the holder may have other shapes such as square.

[0036] According to an aspect of the present invention, the optical sensor 17 is a onedimensional CMOS sensor. According to another aspect of the present invention, the optical sensor 17 is a one-dimensional CCD-detector or a two-dimensional CCD-detector. In case of a two-dimensional CCD-detector a one dimensional recording of the light sheet may be provided by summing all pixels per row to get the one dimensional measurement of the light sheet.

[0037] According to an aspect of the present disclosure, the assembly further comprises a light intensity modulator configured to provide an intensity modulated light sheet. The intensity modulated light sheet is provided by applying to the light sheet an intensity modulation having a periodical, or substantially periodical, pattern in the first spatial direction 101. Accordingly, the light intensity modulator comprises a Ronchi grating for applying to the light sheet an intensity modulation having a periodical, or substantially periodical, pattern in the first spatial direction 101. Ronchi grating are constant-interval bar and space square-wave optical target or mask. The design produces a precisely patterned light source by reflection or illumination, or a stop pattern by transmission, with precise uniformity, spatial frequency, sharp edge definition, and high contrast ratio.

[0038] The second aspect of this disclosure as shown if Figure 4 shows a method for measuring one or more optical parameters of a sample medium using an assembly according to the first aspect, the method comprises step SI of generating a first aspect a light sheet 13 at the light sheet generator 12. The light sheet 13 generated has a propagation path in a second spatial direction 102. Further, the method comprises a step S2 of illuminating the sample 16 of the medium with the light sheet 13. In step S3, the optical sensor 17 records the light sheet after it has passed through the sample 16. Additionally, the method comprises mapping S4 the attenuation through the sample along the first spatial direction 101 of the sensor.

[0039] The person skilled in the art realizes that the present disclosure is not limited to the preferred embodiments described above. The person skilled in the art further realizes that modifications and variations are possible within the scope of the appended claims. Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed disclosure, from a study of the drawings, the disclosure, and the appended claims.

Claims

CLAIMS1. An assembly (1) for measurements of one or more optical parameters of a sample medium, the assembly comprising a light source (11); a light sheet generator (12) configured to receive light from the light source (11) and to provide a light sheet (13) extending in a first spatial direction (101), wherein the light sheet (13) has a propagation path in a second spatial direction (102); a holder (15) for a sample (16) of the medium, configured to enable the light sheet (13) to illuminate the sample (16); an optical sensor (17) with a sensor surface (18) comprising an array of pixels extending in the first spatial direction (101) so as to receive the light sheet when transmitted through the sample (16) in the second spatial direction (102); a control unit (19) with a memory, wherein the control unit (19) is arranged to control the light source (11) and the optical sensor (17); wherein the sensor surface (18) of the optical sensor (17) further extends in a third spatial direction (103), the third spatial direction being perpendicular to the first direction and the second direction, to form a one-dimensional sensor surface for receiving and recording the light sheet (13) after the light sheet (13) has passed through the sample (16).

2. The assembly according to claim 1, wherein the sensor surface (18) has an extension in the third spatial direction (103) that is longer than W, where W is described according to the relationship W = s +2* AD; where s is the width of the light sheet (13) before reaching the sample and AD is the maximum possible displacement of the light sheet (13) from the central axis.

3. The assembly according to any one of the preceding claims, wherein the sample holder is a cuvette.

4. The assembly according to claim 3, wherein the cuvette is cylindrical with an elliptical cross section.

5. The assembly according to claim 3, wherein the cuvette is cylindrical with a rectangular cross section.

6. The assembly according to any one of the preceding claims, wherein the optical sensor (16) is a one-dimensional CMOS sensor.

7. The assembly according to any one of the preceding claims, wherein the optical sensor (16) is a one-dimensional CCD-detector.

8. The assembly according to any one of claims 1-6, wherein the optical sensor (16) is a two-dimensional CCD-detector.

9. The assembly according to any one of the preceding claims, wherein the assembly further comprises a light intensity modulator (14) configured to provide an intensity modulated light sheet (20) by applying to the light sheet (13) an intensity modulation having a periodical, or substantially periodical, pattern in the first spatial direction (101).

10. The assembly according to claim 9, wherein the light intensity modulator comprises a Ronchi grating for applying to the light sheet (13) an intensity modulation having a periodical, or substantially periodical, pattern in the first spatial direction (101).

11. A method for measuring one or more optical parameters of a sample medium using an assembly according to any one of claim 1-10, the method comprising: generating (SI) a light sheet (13) at the light sheet generator (12), wherein the light sheet (13) has a propagation path in a second spatial direction (102); illuminating (S2) the sample (15) of the medium with the light sheet (13); recording (S3) at the optical sensor (17) the light sheet after it has passed through the sample (16).

12. The method according to claim 11, further comprisingmapping (S4) the attenuation through the sample along the first spatial direction (101) of sensor.

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