Photoacoustic detection device

Abstract

Disclosed is a photoacoustic detection device (1) for measuring a parameter of interest in a medium, comprising: a housing (7) comprising a substrate (72) and a cover (71); a light source (2) that emits a light signal; a photoacoustic cell (9) comprising a hollow contact surface (91) in contact with the medium wherein an optical signal propagates from the guiding element (8) in the photoacoustic cell (91) and reaches the medium; a transducer (3) coupled to the photoacoustic cell (9) and configured to detect the generated signal; a first retaining element (100) configured to assemble the light source (2) and the guide element (8) in a building block housed in the housing (7), in which the photoacoustic cell (9) is reversibly attached to the building block by at least one fixing element (95) accessible from outside the housing (7), the photoacoustic cell (9) is dimensioned such that the photoacoustic cell (9) can be removed from the housing (7) through an aperture (721) through a substrate (72) when needed, and wherein a transducer (3) is reversibly coupled to a building block and placed between the building block and the photoacoustic cell (9), the photoacoustic cell (9) can be removed from the aperture (721) of the substrate (72) such that the transducer (3) can be removed from the aperture (721) of the substrate (72) while or after the photoacoustic cell (9) has been removed from the housing (7) or has been removed from the housing (7).

Description

Technical Field

[0001] The present invention relates to a photoacoustic detection device for measuring a parameter of interest in a medium. Background Art

[0002] Photoacoustic detection can be used in the field of detection devices, in particular for detecting parameters of interest, such as chemical components, in a medium.The medium may be an organic tissue, such as human skin.

[0003] Photoacoustic detection is based on the illumination of the medium M to be analyzed by a light signal emitted by a light source. Typically, the light source is one or several lasers, in particular a quantum cascade laser (QCL). The light signal is a beam of selected wavelength. The wavelength is selected with respect to the type of parameter of interest to be measured.

[0004] Photoacoustic detection is based on the detection of pressure waves associated with heat waves. The heat waves are generated under the effect of the absorption of the light beam by the medium. This absorption causes local heating of the chemical components in the medium where the light beam is absorbed. The heat wave propagates in the medium M before propagating out of the medium. More precisely, when the heat wave comes out of the medium after its propagation, a pressure wave is generated that can be detected.

[0005] Photoacoustic detection can be tailored to a specific chemical component by adjusting the wavelength and / or modulation frequency of the light beam. More precisely, the wavelength can be tuned to match the absorption peak of the component to be analyzed.

[0006] Photoacoustic detection is thus a non-invasive way to analyze a medium of interest.A number of photoacoustic detection devices have been developed.

[0007] Such a photoacoustic detection device generally comprises: a photoacoustic cell; a light source emitting a light beam; a guiding element directing the light beam to the photoacoustic cell; and at least one transducer capable of detecting a signal generated in the photoacoustic cell by a photothermal effect in the medium in response to irradiation of the medium with the light beam.

[0008] The main disadvantage of such photoacoustic devices is that they are conceived as one monolithic block comprising the photoacoustic cell, the light source, the guiding element and the transducer. Such detection devices comprising a monolithic block result in the need to replace all monolithic blocks when one element is damaged and needs to be replaced or when a parameter of interest needs to be measured according to different characteristics caused by the structure of the photoacoustic cell, for example. In other words, the entire detection device must be replaced.

[0009] Therefore, an object of the present invention is to at least partially solve the above-mentioned problems. Summary of the invention

[0010] Thus, the present invention relates to a photoacoustic detection device for measuring a parameter of interest in a medium, comprising:

[0011] a housing including a base plate and a cover;

[0012] a light source configured to emit a light signal;

[0013] a photoacoustic cell comprising a contact surface emerging from an aperture of the substrate, the contact surface being intended to be in contact with a medium, wherein an optical signal can propagate in the photoacoustic cell and pass through the contact surface to the medium;

[0014] a guiding structure configured to direct the optical signal to the photoacoustic cell;

[0015] a transducer coupled to the photoacoustic cell and configured to detect a generated signal, wherein the generated signal is generated in the photoacoustic cell by a photothermal effect in the medium in response to the medium being illuminated by the optical signal;

[0016] a first holding element configured to assemble the light source and the guiding element in a building block, the building block being accommodated in the housing,

[0017] It is characterized in that

[0018] a photoacoustic cell reversibly attached to the building block by at least one fixing element accessible from the exterior of the housing, the photoacoustic cell being sized such that the photoacoustic cell may be removed from the housing when desired through an aperture through the base plate, and

[0019] The transducer is reversibly coupled to the building block and positioned between the building block and the photoacoustic cell such that the transducer can be removed from the aperture of the substrate simultaneously with or after the photoacoustic cell is or has been removed from the housing.

[0020] The proposed detection device allows the photoacoustic cell and / or the transducer to be easily and conveniently disassembled when necessary. In fact, since the fixing element is accessible from the outside of the housing, there is no need to remove the cover or open the housing; the photoacoustic cell can be removed directly from the orifice of the base plate. The other components are actually well protected by this particular construction. In addition, since the transducer is reversibly coupled to the building block and is placed between the building block and the photoacoustic cell, once the photoacoustic cell has been removed from the housing or at the same time as the photoacoustic cell is removed from the housing, the transducer can also be removed from the housing without opening the housing.

[0021] It may be necessary to remove the photoacoustic cell and / or transducer in order to clean one or both of the photoacoustic cell and transducer, or to replace one or both of the photoacoustic cell and transducer with another photoacoustic cell or transducer. This may be the case when one of the two components is damaged or when a photoacoustic cell or transducer with different characteristics is needed to analyze the parameters of interest.

[0022] According to an embodiment, the transducer is attached to a second holding element, the second holding element comprising a connecting portion with respect to the first holding element, and wherein the connecting element is configured to reversibly connect the connecting portion of the second holding element to the first holding element so as to ensure a mechanical, electronic and / or electrical connection between the transducer and the building block.

[0023] Typically, the transducer needs to be permanently connected to a component that allows the generated detection signal to be analyzed. For example, this connection can be a wire or soldering of the transducer. In the present application, the connecting element ensures the connection of the transducer to such an analysis component, while allowing the transducer to be easily disassembled from the detection device when necessary. More particularly, the connecting element allows a mechanical connection of the transducer to a building block so that the transducer cannot move back and forth in the housing, and / or allows an electronic connection of the transducer to a building block, the building block carries a component for analyzing the generated signal detected by the transducer, and / or allows an electrical connection of the transducer to a building block.

[0024] According to an embodiment, removing the transducer to the exterior of the housing comprises removing the transducer and the second retaining element.

[0025] When the user needs to remove or clean the transducer, it means that they need to replace it with the same transducer or a new transducer afterwards. However, it may be complicated to correctly place and fix the transducer inside the housing when the housing is closed. In fact, if the transducer is not placed correctly, the generated signal may not be properly detected.

[0026] The purpose of the present application is to allow replacement of the transducer without disassembly of the entire detection device.

[0027] Due to this particular construction, when the user needs to replace the transducer, they actually need to replace the assembly consisting of the transducer and the second holding element. Since the connecting portion of the second holding element is placed with respect to the connecting element, the assembly is easier to replace than the transducer. The user can then detect when the second holding element is in a good position, and therefore detect when the transducer is in a good position.

[0028] According to one embodiment, the connecting element is soldered to the first holding element.

[0029] Since the connecting element is permanently attached in the detection device, the placement of the assembly made of the transducer and the second holding element is facilitated for the user.

[0030] According to an embodiment, the connecting element is a reed connector.

[0031] Since leaf springs are used as components in the field of electronics, they are easy to manufacture. In addition, leaf spring connectors are generally inexpensive.

[0032] According to an embodiment, fastening the photoacoustic cell to the detection device by means of the fixing element is configured to press the second holding element against the connecting element.

[0033] Such a configuration thereby ensures a good connection of the transducer to the building block via the connecting element.

[0034] More specifically, the photoacoustic cell includes an extension portion contacting the second holding element and surrounding the transducer, the extension portion pressing the second holding element against the connecting element.

[0035] According to an embodiment, the photoacoustic cell comprises an extension portion reversibly attached to the second holding element, the extension portion surrounding the transducer.

[0036] Due to this configuration, the photoacoustic cell can be removed from the detection device without also removing the transducer. This is particularly advantageous in situations where the user needs to change one component. In fact, when only one of the transducer and the photoacoustic cell needs to be replaced, the user can simply place the new transducer and replace the old photoacoustic cell (or vice versa) without replacing both the transducer and the photoacoustic cell.

[0037] According to an embodiment, the extension portion of the photoacoustic cell comprises a stud configured to cooperate with a hole provided on the second holding element.

[0038] This configuration facilitates the placement of the photoacoustic cell back into the detection device. Since it is necessary to ensure tightness between the photoacoustic cell and the transducer to allow good photoacoustic detection, the studs and holes allow the user to know exactly when the photoacoustic cell is in a good position inside the detection device. This is particularly useful when the photoacoustic cell is removed from the detection device alone and needs to be replaced back.

[0039] According to an embodiment, the photoacoustic cell comprises an extension portion permanently attached to the second holding element, the extension portion surrounding the transducer.

[0040] Due to this configuration, the photoacoustic cell and the transducer are removed from the detection device together. This may be particularly advantageous when the user only needs to clean two parts, since only one step is required to remove the transducer and the photoacoustic cell.

[0041] According to an embodiment, the photoacoustic cell is attached to the second holding element by means of an adhesive such as a double-sided tape.

[0042] According to an embodiment, the fixing element reversibly attaching the photoacoustic cell to the building block is a threaded element, wherein the head of the threaded element is accessible from outside the housing.

[0043] The skirt may improve user comfort and may conceal fixing elements of the photoacoustic cell.

[0044] The present application also relates to a photoacoustic detection device kit, comprising the photoacoustic detection device according to the present application and a plurality of photoacoustic cells, wherein the plurality of photoacoustic cells exhibit different acoustic properties and have the same reversible fixing element, so that each of the plurality of photoacoustic cells is configured to be interchangeable in the photoacoustic detection device.

[0045] Since the photoacoustic detection device is detachable, providing a kit of different photoacoustic cells allows the user to interchange one cell with another when needed. Advantageously, the cells exhibit different acoustic properties, so that different cells can be used to measure different parameters or signals.

[0046] According to an embodiment, the photoacoustic detection device kit further comprises a plurality of transducers of different types and / or exhibiting different characteristics, and each transducer of the transducer kit is attached to a holding element having the same size and characteristics as the second holding element, so that all transducers of the transducer kit are configured to be interchangeable in the photoacoustic detection device.

[0047] Thus, the user can also change the transducer when, for example, a different signal needs to be measured. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Embodiments of the present invention will now be described with reference to the accompanying drawings briefly described below:

[0049] Figure 1 Represents a photoacoustic detection device worn on the arm of person P.

[0050] Figure 2 is a block diagram of a photoacoustic detection device.

[0051] Figure 3 is a schematic representation of the interior of a photoacoustic detection device according to an embodiment.

[0052] Figure 4 is another schematic representation of the interior of a photoacoustic device.

[0053] Figure 5 is a top view of the second holding element.

[0054] In the drawings, the same reference numerals refer to the same or similar objects. DETAILED DESCRIPTION

[0055] The invention relates to a photoacoustic detection device 1 for measuring a parameter of interest in a medium M.

[0056] In a non-limiting example, the photoacoustic detection device 1 (or “detection device 1 ” in the following description) is intended to be worn by a person P. The medium M may be an organic tissue such as the skin of the person P wearing the detection device 1 .

[0057] The parameters of interest may be chemical components such as molecules present in the skin of the person P. The parameters of interest may include glucose, cholesterol, triglycerides, urea, albumin and / or alcohol. This list is not exhaustive and several other parameters of interest may be measured.

[0058] The measured parameters can then be analyzed to determine blood concentrations of glucose, cholesterol, etc.

[0059] like Figure 1 As shown, the detection device 1 can be worn on the arm or wrist of the person P. The detection device 1 can be fixed to the arm of the person P by means of a bracelet.

[0060] The detection device 1 may allow continuous monitoring of the person P by repeatedly measuring parameters of interest of the person P while being worn.

[0061] Figure 2 is a block diagram of the detection device 1.

[0062] The detection device 1 comprises:

[0063] at least one light source 2 configured to emit a light signal;

[0064] A transducer 3, which acquires a signal from the medium M;

[0065] The signal processing module 4 is used to analyze the signal detected by the transducer.

[0066] In an embodiment, the transducer 3 may be an acoustic transducer that detects an acoustic signal generated in response to the irradiation of the medium M with an optical signal.

[0067] The transducer 3 may be connected to the signal processing module 4 , such that the signal processing module 4 receives the signal from the transducer 3 .

[0068] In a non-limiting embodiment, the signal processing module 4 may include an analog-to-digital converter that converts the signal acquired by the transducer 3 into a digital signal.

[0069] In another embodiment, the transducer 3 may directly send a digital signal to the signal processing module 4 .

[0070] The signal processing module 4 may be implemented in a processor (not shown), which may be located away from the detection device 1 or not.

[0071] The detection device 1 may include other components. For example, the detection device 1 may also include an adaptation module 5 and a memory 6, for example, for adapting the illumination parameters of the light source 2. These components will not be described further.

[0072] In an embodiment, the light source 2 emits a light signal at a selected wavelength towards the medium M to be analyzed. The selected wavelength may be selected according to the parameter of interest to be measured.

[0073] More precisely, the wavelength may correspond to the absorption peak of the parameter of interest to be measured. As an example, for the detection of glucose, the wavelength may be 1034 cm -1 , which corresponds to the absorption peak of glucose.

[0074] The light source may be a laser, and more particularly a quantum cascade laser (QCL). In a variant embodiment, the light source 2 may be an electroluminescent diode (LED).

[0075] In an embodiment, the detection device 1 may include a plurality of light sources 2. In this embodiment, each light source 2 may emit light signals of different wavelengths. In a variation, some light sources 2 emit light signals of the same wavelength, while other light sources 2 emit light signals of different wavelengths.

[0076] In the following description, the detection device 1 is described as including only one light source 2 , but it should be understood that the same specification applies to a plurality of light sources 2 .

[0077] The light signal emitted by the light source 2 propagates to the medium M and passes through the medium M. This phenomenon is caused by Figure 2 The light signal is absorbed by the components of the medium M at a depth z, which depends on the selected wavelength of the light signal, the frequency of the light signal and the composition of the medium M.

[0078] The absorption of the optical signal energy causes local heating of the medium M. Therefore, the thermal signal propagates in the medium M ( Figure 2 ), in particular propagating towards the surface of the medium M. Moreover, the thermal wave can generate a pressure wave outside the medium M that propagates outside the medium M. Such a pressure wave can be detected by the acoustic transducer 3.

[0079] In an embodiment, the heat waves can also be detected by means of a heat transducer (such as a thermometer) not shown in the figure.

[0080] The detection device 1 may comprise an acoustic and / or thermal transducer 3. Other types of transducers 3 may be used.

[0081] In the figure, two transducers 3 are shown, whereas only one or more than two transducers 3 may be used.

[0082] In the following description, the detection device 1 is described as comprising only one transducer 3. It should be understood that what is described for one transducer is applicable to several transducers 3.

[0083] Figure 3 A detection device 1 according to an embodiment is schematically illustrated.

[0084] The detection device 1 may include a housing 7 formed by a cover 71 and a base plate 72. The housing 7 includes an interior defined by an inner surface 710 of the cover 71 and an inner surface 720 of the base plate 72.

[0085] The interior of the housing 7 accommodates the light source 2, which may be a QCL as described above.

[0086] There is also provided a guiding element 8. The guiding element 8 is configured to guide the light signal emitted by the light source 2 towards the medium M to be analyzed.

[0087] In embodiments where the detection device 1 comprises a plurality of light sources 2 , the guiding element 8 may also be configured to collimate the individual light signals emitted by the individual light sources 2 into a single light signal directed towards the medium M to be analyzed.

[0088] More specifically, the guiding element 8 is configured to guide the optical signal emitted by the light source 2 through a photoacoustic cell 9 (or “cell 9 ” in the following description) placed between the medium M to be analyzed and the light source 2 .

[0089] The cell 9 extends from the guide element 8 to a hollow contact surface 91 of said cell 9 through which the medium M is accessible. The cell 9 comprises a cavity 92 and a channel 93. The light signal emitted by the light source 92 propagates in the photoacoustic cell 9 by first entering the cavity and then passing through the hollow contact surface 91.

[0090] The hollow contact surface 91 may generally present a ring shape. The hollow contact surface 91 may have a circular shape, and the hollow portion may be located at the center of the circle, and may also present a generally circular shape. Other configurations are also possible.

[0091] The hollow portion of the hollow contact surface 91 may be closed by a window of a transparent material such as silicon, thereby allowing optical signals to pass through it.

[0092] The hollow contact surface 91 may be intended to be placed against the medium M to be analyzed, more precisely, may be placed in direct contact with the medium M to be analyzed.

[0093] Then, when the person P wears the detection device 1, as shown in FIG. Figure 1 As shown, the hollow contact surface 91 is placed directly against the skin of the person P.

[0094] To this end, the base plate 72 comprises an orifice 721 from which emerges the hollow contact surface 91. Thus, the hollow contact surface 91 of the cell 9 is located outside the interior of the housing 7 and can be placed in direct contact with the medium M to be analyzed.

[0095] With regard to photoacoustic detection, a heat wave is generated under the effect of the absorption of the light beam emitted by the light source by the medium. This absorption causes local heating of the chemical components in the medium in which the light beam is absorbed. The heat wave propagates in the medium M before propagating out of the medium. When the heat wave comes out of the medium after its propagation, a pressure wave is generated, which propagates in the cell 9 where it can be detected. Then, the pressure wave, i.e., an acoustic wave, is induced by the photothermal effect.

[0096] The transducer 3 is located inside the housing 7 and is preferably connected to the pool 9 by means of a channel 93 including an outlet facing the transducer 3, so that the transducer 3 can detect and measure the generated pressure wave. More precisely, the generated pressure wave propagates from the hollow contact surface 91, then propagates within the channel 93, to finally reach the transducer 3 through the outlet of the channel 93.

[0097] In embodiments where the detection device 1 comprises more than one transducer 3 , the channel 93 may comprise as many outlets as there are transducers 3 .

[0098] Since it may be necessary to replace an element of the detection device 1 for some reason, the detection device according to the present application is conceived to be modular, i.e. an element can be changed or replaced without replacing the entire detection device 1. Such an element may in particular be a photoacoustic cell 9 and / or a transducer 3. The reason for this need for replacement is that the element may be damaged, the element needs to be cleaned, or the parameter of interest can be analyzed according to different characteristics that the photoacoustic cell 9 and / or the transducer used do not allow.

[0099] In order to solve this technical problem, the detection device is provided with a first holding element 100. The first holding element 100 may be a metal plate or a printed circuit board (PCB). The first holding element 100 is used to hold the light source 2 and the guiding element 8 and other electronic components not described herein together.

[0100] In the example, the first holding element 100 holds the light source 2 and the guiding element 8 in a non-removable manner, which means that the light source and the guiding element cannot or cannot easily be separated from the holding element.

[0101] For example, the light source 2 and the guiding element 8 may be attached to the holding element by means of threaded elements which are not accessible to a user. The threaded elements may only be accessible by completely disassembling the detection device 1 .

[0102] Thus, the first holding element 100, the light source 2 and the guiding element 8 form a single building block. The single building block is considered on film to be a rigid body in normal use.

[0103] The individual building blocks may also include an analog-to-digital converter, a signal processing module, an adaptation module 5 and / or a memory 6 .

[0104] In the following description, it is considered that the first holding element is the first PCB 100 , but other applications and implementations also fall within the scope of the present application.

[0105] The first PCB 100 also ensures electronic and / or electrical connections between the components of the building block. In other words, the first PCB ensures electronic, electrical and mechanical connections between the components of the building block.

[0106] Regarding the attachment of the photoacoustic cell 9 in the detection device 1, Figure 4 can be seen more precisely in .

[0107] As described above, the cell 9 includes the hollow contact surface 91 emerging from the aperture 721 of the base plate 72 .

[0108] When viewed from the outside of the housing 7, the hollow contact surface 91 generally appears annular. Figure 3 or Figure 4 As can be seen from the profile on the top, the hollow contact surface 91 presents a dome shape or a cone shape. This shape helps to maintain constant contact between the medium to be analyzed and the hollow contact surface 91.

[0109] Other shapes may also be used and are within the scope of the present application.

[0110] In order to attach the photoacoustic cell 9 to the rest of the detection device 1, a fixing element 95 may be used. Such a fixing element may be used to removably attach the photoacoustic cell to the guiding element 8. The fixing element 95 may be a threaded element, the head of which may be accessible from the outside of the housing 7. Alternatively, the fixing element may be a clamping element.

[0111] Therefore, if necessary, the photoacoustic cell 9 can be easily removed from the detection device 1 by loosening the fixing element 95, i.e., unscrewing the threaded element or loosening the clamping element, without disassembling the entire detection device 1. In order to allow such disassembly, the size of the photoacoustic cell 9 and the aperture of the substrate 72 are designed.

[0112] The skirt 96 may be disposed on top of the hollow contact surface 91 without covering the hollow portion of the hollow contact surface 91. The skirt 96 may extend beyond the hollow contact surface 91 to the outer surface of the base plate 72. The skirt 96 may be a soft and / or slightly elastic material, such as rubber or silicone.

[0113] The advantage of this embodiment is that the material used for the skirt and the gluing between skirt 96 and sump 9 allow ensuring the tightness of sump 9 with respect to the environment, ie watertightness and dusttightness.

[0114] As an alternative, a sealing element 98 may be provided between the skirt 96 and the pool 9 to ensure tightness. For example, the sealing element 98 may be overmolded on the hollow contact surface of the pool 9 or on the periphery of the skirt, or the sealing element 98 may be inserted between the hollow contact surface of the pool 9 and the skirt 96 and glued on the hollow contact surface of the pool 9 or on the periphery of the skirt 96.

[0115] The skirt 96 may conceal the head of the threaded element 95. Therefore, in order to remove the photoacoustic cell 9 when necessary, any suitable product may be used that is capable of separating the skirt 96 from the hollow contact surface 91. Such a product may be a solvent or an alcohol.

[0116] In another embodiment, the skirt 96 can be a clampable skirt 96 that can be clamped on a pin (not shown) provided on the hollow contact surface 91 of the pool 9. The skirt 96 can be a soft elastic material, such as plastic or silicone. In this embodiment, the skirt 96 can be first loosened from the pool 9 to access the threaded element 95.

[0117] In order to ensure the tightness of the pool 9 relative to the environment, i.e., watertightness and / or dustproofness, a sealing element 98 can be provided between the skirt 96 and the pool 9 to ensure tightness. For example, the sealing element 98 can be overmolded on the hollow contact surface of the pool 9 or on the periphery of the skirt, or the sealing element 98 can be inserted between the hollow contact surface of the pool 9 and the skirt 96 and glued on the hollow contact surface of the pool 9 or on the periphery of the skirt 96.

[0118] Although the use of skirt 96 is optional, it may improve the contact between hollow contact surface 91 and the medium to be analyzed, it may improve the comfort of the user wearing detection device 1, and it may improve the hold between photoacoustic cell 9 and the housing.

[0119] In addition, from Figure 3 As can be seen in the figure, the pool 9 including the hollow contact surface 91, the cavity 92 and the channel 93 is formed as a whole, i.e., as a single piece. The pool 9 can be made of one material, such as silicon or resin, or the pool can be made of two or more materials, such as silicon and resin.

[0120] Making the photoacoustic cell 9 as a single piece allows for reduced manufacturing costs while allowing for easy and quick assembly of the cell 9 to the detection device 1 .

[0121] In order to enable detection of the signal generated by the transducer 3 , a second holding element 110 is provided in the detection device 1 .

[0122] The second holding element 110 may be a metal plate or a printed circuit board (PCB). In the following description, it is considered that the second holding element is the second PCB 110, but other applications and implementations also fall within the scope of the present application.

[0123] like Figure 3 It can be seen that the second PCB 110 includes a first surface facing the first PCB 100 and a second surface facing the substrate 72 .

[0124] In an embodiment, the transducer 3 is held to the second face of the second PCB 110 by soldering. In this embodiment, the transducer is non-removably attached to the second PCB 110.

[0125] Therefore, when the user needs to remove the transducer 3 from the detection device 1, the transducer 3 and the second holding element are removed together. Since the transducer 3 and the second holding element are removed from the aperture of the substrate 72, the size of the second holding element 110 can be designed to fit through the aperture 721 of the substrate. Figure 5 In the example shown, the retaining element 110 may take the general form of a U.

[0126] When the transducer 3 detects the generated signal, the information contained in the generated signal can be sent to a component involved in the analysis of the detected generated signal. The component can be an analog-to-digital converter or a signal processing module 4. In a preferred embodiment, the first PCB 100 carries the analog-to-digital converter or the signal processing module 4, or at least carries the means required to send the information detected by the transducer to the analog-to-digital converter or the signal processing module 4. Thus, a bridge can be realized between the first PCB 100 and the transducer 3.

[0127] For the need to have a modulatable detection device 1, where the transducer 3 can be separated from the rest of the detection device 1, a bridge can be created by a connecting element. The connecting element can take the form of a leaf spring connector 31. In the following description, it is considered that the connecting element is a leaf spring connector, while other types of connectors having the same functionality as a leaf spring connector can be used.

[0128] Advantageously, the second PCB 110 includes a connecting portion 111. Figure 3 It can be seen that the leaf spring connector 31 can couple the connection portion 111 of the second PCB 110 to the first PCB 100 on which the leaf spring connector 31 is soldered.

[0129] In an embodiment, the leaf spring connector 31 is soldered on the first PCB 100 , so that the leaf spring connector 31 cannot be removed from the inside of the detection device 1 without disassembling the detection device 1 .

[0130] Advantageously, the distance between the first PCB 100 and the second PCB 110 is such that the leaf spring connector 31 placed therebetween is in a slightly compressed state.

[0131] Advantageously, the compressed state is obtained by attaching the fixing element of the cell 9 to the detection device, ie by screwing the threaded element 95 or by clamping the clamping element.

[0132] Hence, the leaf spring connector 31 and the connecting portion 111 together allow an electronic, mechanical and / or electrical connection between the transducer 3 and the rest of the electronics, and more preferably they allow an electronic, mechanical and electrical connection between the transducer 3 and the rest of the electronics.

[0133] Since leaf springs are commonly used as components in the field of electronics, this construction allows very easy manufacturing. It also reduces manufacturing costs. In addition, when the detection device 1 is used, the elasticity of the leaf spring connector 31 in a compressed state ensures a permanent connection between the connecting portion 111 of the first PCB 100 and the second PCB 110. Finally, the use of the leaf spring connector 31 provides a mechanical, electronic and / or electrical connection without any fixing elements.

[0134] In an embodiment, each PCB may include several connection portions 111 , and several leaf spring connectors 31 may be used.

[0135] Furthermore, the second PCB 110 may be used to allow a mechanical connection between the pool 9 and the transducer. In an embodiment, the pool 9 may present an extension 97 in contact with the second face of the second PCB 110 surrounding the transducer 3. In order to perform a mechanical connection between the pool 9 and the second PCB 110, an adhesive may be applied between the extension 97 of the pool and the second face of the second PCB 110. Such an adhesive may be a non-permanent adhesive, so that the pool 9 may be separated from the second PCB 110 when necessary. As an example, such an adhesive may be a double-sided tape.

[0136] According to the above embodiment, when access to the photoacoustic cell 9 and / or the transducer 3 is required, the user can simply remove the photoacoustic cell 9 from the detection device and replace it with another photoacoustic cell. To this end, if appropriate, the user can first separate the skirt 96 from the base plate 72 by using a solvent or loosening the skirt 96. Then, unscrew the threaded element 95 and remove the photoacoustic cell 9 from the interior of the housing through the orifice 721 of the base plate 72. Advantageously, by gently pulling the photoacoustic cell 9 through the orifice, the extension 97 of the cell 9 will be separated from the second PCB 110 due to the type of adhesive used to hold the cell 9 to the second PCB 110.

[0137] If the transducer 3 needs to be replaced, the same operation is performed with respect to the photoacoustic cell 9 , and then the transducer 3 and the second PCB 110 soldered to the second PCB 110 can be taken out from the housing 7 through the aperture 721 of the base plate 72 .

[0138] To replace the transducer 3 and the photoacoustic cell 9, the user can insert a new or identical transducer into the detection device 1 through the aperture 721 of the base plate. Advantageously, if a new transducer 3 is placed, the transducer 3 has been soldered on a PCB corresponding to the second PCB 110. The second PCB 110 with the transducer 3 soldered thereon is inserted so that the connection portion of the second PCB 110 faces the leaf spring connector 31.

[0139] Then, the photoacoustic cell 9 or a new photoacoustic cell is placed inside the detection device 1 through the orifice 721 .

[0140] In order to facilitate the installation of the photoacoustic cell 9 inside the detection device 1, a stud 99 can be provided on the extension 97 of the cell 9, and the stud 99 cooperates with the corresponding hole 112 on the second PCB 110. Figure 5 Therefore, the user can know when the photoacoustic cell 9 is in place. In addition, the stud 99 and the hole 112 are used to align the transducer 3 and the channel 94 of the cell 9 to allow tightness between the channel 94 of the cell 9 and the transducer 3. In other words, in the detection of the signal, the stud 99 and the hole 112 help to avoid any leakage due to poor tightness or poor alignment between the cell 9 and the transducer 3.

[0141] In another embodiment, the adhesive used to hold the pool 9 to the second PCB 110 does not allow the pool 9 and the second PCB 110 to be separated by simply pulling the pool 9 out of the housing. Therefore, when the pool 9 is removed from the housing 7, the transducer 3 and the second PCB 110 also come out of the housing with the pool 9.

[0142] In an embodiment, outside the housing 7, the user can separate the cell 9 from the second PCB 110 by pulling it. The transducer and / or photoacoustic cell 9 or a new transducer 3 and / or a new photoacoustic cell 9 can then be replaced as described above.

[0143] In another embodiment, due to the type of adhesive used, the cell 9 cannot be separated from the second PCB 110. Therefore, after having removed the assembly formed by the transducer, the second PCB and the cell, the user can replace the same assembly or a new assembly comprising the transducer soldered on the second PCB and the photoacoustic cell glued to the second PCB.

[0144] In all the above-described embodiments, after having replaced the elements inside the detection device, the user can then screw back the threaded element 95 and, if applicable, place the skirt 96 on top of the hollow contact surface of the cell 9 .

[0145] As discussed above, it may be desirable to use photoacoustic cells 9 and / or transducers having different characteristics so that different parameters of interest can be analyzed.

[0146] For this purpose, the detection device 1 can be provided with a set of different photoacoustic cells 9 and / or different transducers 3 .

[0147] Advantageously, the transducer 3 of the kit has been soldered to the PCB.

[0148] Advantageously, the kit comprises a plurality of components including a photoacoustic cell glued to a PCB and a transducer soldered to said PCB. The various components may comprise different characteristics allowing different analysis and detection of the parameters of interest.

[0149] The transducers included in the kit may be of different types, such as thermal, acoustic, etc. The photoacoustic cells 9 included in the kit may also have different features. In a non-limiting embodiment, some cells 9 of the kit may include a hollow contact surface 91 or may include a window to restore the hollow contact surface 91. Other features may be implemented.

[0150] Although exemplary embodiments of the present invention have been described with reference to two main embodiments, it will be appreciated by those skilled in the art that various changes, omissions and / or additions may be made, and that elements thereof may be replaced with equivalents, without departing from the spirit and scope of the present invention. In addition, many modifications may be made to adapt specific situations or materials to the teachings of the present invention without departing from the scope of the present invention. Therefore, it is contemplated that the present invention is not limited to the specific embodiments disclosed as the best mode for implementing the present invention, but that the present invention will include all embodiments falling within the scope of the appended claims. Moreover, unless otherwise specified, any use of the terms first, second, etc. does not indicate any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another.

Claims

1. A photoacoustic detection device (1) for measuring a parameter of interest in a medium, comprising: A housing (7) comprising a base plate (72) and a cover (71); a light source (2) configured to emit a light signal; a photoacoustic cell (9), comprising a hollow contact surface (91) exposed from an orifice (721) of the substrate (72), the hollow contact surface (91) being intended to be in contact with the medium, wherein the optical signal can propagate in the photoacoustic cell (91) and pass through the hollow contact surface (91) to reach the medium; a guiding element (8) configured to guide the optical signal to the photoacoustic cell (9); a transducer (3) coupled to the photoacoustic cell (9) and configured to detect a generated signal, wherein the generated signal is generated in the photoacoustic cell (9) by a photothermal effect in the medium in response to the medium being illuminated by the optical signal; a first holding element (100) configured to assemble the light source (2) and the guiding element (8) in a building block, the building block being accommodated in the housing (7), It is characterized in that The photoacoustic cell (9) is reversibly attached to the building block by at least one fixing element (95) accessible from the outside of the housing (7), the photoacoustic cell (9) being of such a size that the photoacoustic cell (9) can be removed from the housing (7) when necessary by passing through the aperture (721) of the base plate (72), and The transducer (3) is reversibly coupled to the building block and is placed between the building block and the photoacoustic cell (9) so that the transducer (3) can be removed from the aperture (721) of the substrate (72) at the same time as or after the photoacoustic cell (9) is removed from the housing (7) or has been removed from the housing (7).

2. The photoacoustic detection device (1) according to claim 1, wherein: The transducer (3) is attached to a second retaining element (110), the second retaining element (110) comprising a connecting portion (111) with respect to the first retaining element (100), and wherein the connecting element is configured to reversibly connect the connecting portion (111) of the second retaining element (110) to the first retaining element (100) so as to ensure a mechanical, electronic and / or electrical connection between the transducer (3) and the building block.

3. The photoacoustic detection device (1) according to claim 2, wherein: Removing the transducer (3) to the outside of the housing (7) includes removing the transducer (3) and the second retaining element (110).

4. The photoacoustic detection device (1) according to claim 2 or 3, wherein: The connecting element is soldered to the first retaining element (100).

5. The photoacoustic detection device (1) according to any one of claims 2 to 4, wherein: The connecting element is a spring connector (31).

6. The photoacoustic detection device (1) according to any one of claims 2 to 5, wherein: Fastening the photoacoustic cell (9) to the detection device (1) using the fixing element (95) is configured to press the second retaining element (110) against the connecting element.

7. The photoacoustic detection device (1) according to any one of claims 2 to 6, wherein: The photoacoustic cell (9) comprises an extension portion (97) reversibly attached to the second holding element (110), the extension portion (97) surrounding the transducer (3).

8. The photoacoustic detection device (1) according to claim 7, wherein: The extension portion (97) of the photoacoustic cell (9) includes a stud (97) configured to cooperate with a hole (112) provided on the second retaining element (110).

9. The photoacoustic detection device (1) according to any one of claims 2 to 6, wherein: The photoacoustic cell (9) comprises an extension portion (97) permanently attached to the second holding element (110), the extension portion surrounding the transducer (3).

10. The photoacoustic detection device (1) according to any one of claims 2 to 9, wherein: The photoacoustic cell (9) is attached to the second holding element (110) by an adhesive such as a double-sided tape.

11. The photoacoustic detection device (1) according to any one of claims 1 to 10, wherein: The fixing element (95) reversibly attaching the photoacoustic cell (9) to the building block is a threaded element, wherein the head of the threaded element is accessible from outside the housing (7).

12. The photoacoustic detection device (1) according to any one of claims 1 to 11, further comprising a skirt (96) arranged on the surface of the hollow contact surface (91) of the photogenerating cell (9), wherein the skirt (96) is reversibly attached to the detection device (1).

13. A photoacoustic detection device kit, comprising: The photoacoustic detection device (1) according to any one of claims 1 to 12; A plurality of photogenerating cells (9) exhibiting different acoustic properties and having the same reversible fixing element (95), such that each photogenerating cell (9) in the plurality of photogenerating cells (9) is configured to be interchangeable in the photoacoustic detection device (1).

14. The photoacoustic detection device kit according to claim 13, further comprising a plurality of transducers (3) of different types and / or exhibiting different characteristics, wherein each transducer (3) of the transducer (3) kit is attached to a holding element having the same size and characteristics as the second holding element (110), so that each transducer (3) of the plurality of transducers (3) is configured to be interchangeable in the photoacoustic detection device (1).

Images