FR3118174A1 - DEVICE AND METHOD FOR CHARACTERIZING A SUBSTRATE IN A DIRTY ENVIRONMENT - Google Patents

Abstract

The invention relates to a device (1) for characterizing a substrate in a dirty environment, comprising an enclosure (4), means (16) making it possible to generate dirty particles (44) in the enclosure, and equipment (14 ) for measuring the fouling of the substrate, the equipment comprising a light source (20) capable of generating a light beam (12) to irradiate the substrate to be characterized in the enclosure. The device also comprises a member (30) for protecting an optical part (10) of the outer wall of the enclosure against the deposit of dirty particles (44), this member (30) being configured to be moved: - d a position of protection of the optical part (10) in which it covers this optical part (10) so as to prevent the deposition thereon of dirty particles; - in a retracted position in which the protection member (30) releases the optical part (10). Figure for abstract: Figure 1.

Description

DEVICE AND METHOD FOR CHARACTERIZING A SUBSTRATE IN A DIRTY ENVIRONMENT

The present invention relates to the field of the characterization of a substrate in a dirty environment. It relates more particularly to the characterization of a photovoltaic panel, but generally applies to any substrate, such as glass panels.

PRIOR ART

The characterization of a substrate in a dirty environment is usually carried out by carrying out a fouling test. This test is implemented using a chamber, inside which the natural fouling phenomena are reproduced. To do this, the substrate is placed in the enclosure which is preferably regulated in temperature and humidity. When the desired temperature and humidity conditions are stabilized, fouling particles, such as a dust cloud, are sprayed into the interior space of the enclosure.

When the dirty particles have deposited on the substrate to be characterized, it is carefully extracted from the enclosure and moved to a measuring station where the fouling test can be carried out, using appropriate equipment. such as spectrophotometer, flash-test equipment, microscope, etc.

When transferring the dirty substrate between the chamber and the measuring station, dirty particles can fall or be blown off. Subsequent tests may therefore lack precision, or even be unusable.

In addition, when the same substrate must be tested successively under different conditions, extracting this substrate from the enclosure for each new test is extremely time-consuming.

The object of the invention is therefore to at least partially remedy the drawbacks mentioned above, relating to the embodiments of the prior art.

To do this, the invention firstly relates to a device for characterizing a substrate in a dirty environment, configured to carry out a soiling test of the substrate, the device comprising an enclosure comprising an outer wall delimiting an inner space for housing the substrate to be characterized, as well as a means making it possible to generate messy particles in the enclosure.

According to the invention, the device further comprises measurement equipment arranged outside the enclosure, at least partially facing an optical part of the outer wall, so as to allow transmission of light between the measurement equipment and the substrate, along an optical axis passing through the measurement equipment, the optical part, as well as this substrate to be characterized in the interior space.

In addition, the device also comprises a member for protecting the optical part of the outer wall of the enclosure against the deposition of dirty particles, as well as a means for moving the protective member configured to move this member :
- A protective position of the optical part in which the protective member, in the interior space of the enclosure, covers this optical part so as to prevent the deposition thereon of dirty particles;
- In a retracted position in which the protective member releases the optical part of the outer wall of the enclosure.

The invention thus breaks with the existing solutions, by providing a device making it possible to carry out the fouling test with the dirty substrate remaining permanently in the interior space of the enclosure. Thanks to this principle, the absence of transfer of the dirty substrate avoids the risk of loss of particles, which advantageously results in better measurement accuracy. In addition, the tests carried out successively on the same substrate, in different dirty environments, can be linked more quickly by keeping this substrate inside the enclosure.

Furthermore, it is noted that the invention advantageously provides a protective device for the optical part of the enclosure, intended to allow transmission of light between the measuring equipment and the substrate. In the protective position and when dirty particles are generated within the enclosure to be deposited on the substrate, this device protects the optical part of the outer wall of the enclosure against the deposition of these same particles. Advantageously, this avoids fouling of the optical part of the enclosure during the phase of depositing dirty particles on the substrate, with the consequence of better measurement accuracy when the light passes through this same optical part, during the phase. subsequent substrate fouling test.

As will be detailed later, the principle of the invention explained above can be implemented with the measuring equipment comprising a light source to generate a beam of light along the optical axis, so that this beam can irradiate the substrate to be characterized. Alternatively, the light source can be the substrate itself, the measurement equipment then fulfilling in this case the only function of receiving light, and not that of emitting light.

The invention preferably has at least one of the following optional features, taken individually or in combination.

According to a first preferred embodiment of the invention, the protective member is a protective film.

Preferably, in the protective position, the protective film corresponds to an unrolled part of a roll of film, and the moving means is configured to allow the displacement of this protective film from the protective position to the position shrinkage, by additional unwinding of the roll of film, also causing an adjacent unwound part of the roll to form another protective film occupying the protective position of the optical part. This other protective film is intended to be crossed by the light beam from the measuring equipment, during the substrate test phase, carried out after the phase of displacement of the dirty protective film from the protective position. to the retracted position. Advantageously, the positioning of this other protective film allows it to already be in place for the protection of the optical part of the enclosure, during a new characterization of a substrate involving the generation of dirty particles within this even pregnant.

Preferably, the film forming the roll has properties of transparency vis-à-vis the light beam generated by the light source, in the event that such a light source is integrated. In other words, since it is preferentially ensured that the protective film is crossed by the beam of light during a characterization of the substrate, before fulfilling its primary function of protecting the optical part of the enclosure during a subsequent characterization, the film used requires good transparency properties. To illustrate this need, it is for example ensured that the film has a transmittance greater than 60% in the spectrum of the light beam implemented by the device. For example, the transmittance of the film can be set around 80%. This transmittance, also called transmittance or transparency, has a high value which allows the protective film to be preferably totally transparent to semi-transparent, with the aim of disturbing as little as possible the beam of light supposed to irradiate the substrate at inside the enclosure, and the signal/image received by the sensor of the fouling measuring equipment. These transparency properties are also adopted when the light source is formed by the substrate itself.

Preferably, the device comprises a cassette fitted with the roll of film, as well as a roll of used film in which the protective film is rolled up in its retracted position. Nevertheless, it is specified that the unwinding of the roll of film is not necessarily accompanied by a re-winding of the film consumed, the latter can simply be deposited, inside or outside the enclosure.

Preferably, the device comprises a cleaning means making it possible to remove at least some of the soiling particles deposited on the protective film, during its movement between its protective position and its removal position. The removal of the dirty particles makes it possible to rewind the protective film consumed in a clean state, thus making it possible to reuse this same film in a reverse direction of operation of the cassette.

Preferably, the cleaning means is a squeegee, a brush, a suction means, or any other similar means.

Preferably, in the protective position, the protective film is in contact with the outer wall of the enclosure, and preferably in contact with the optical part of this outer wall. This arrangement makes it possible to best limit the risk of depositing dirty particles on the optical part of the enclosure.

According to a second preferred embodiment of the invention, the protection member is a movable flap between the protection position and the retracted position. In the shutter retracted position, the optical part of the enclosure is preferentially not covered by any element, so that the beam of light passing through it is not disturbed in any way.

Preferably, the moving means is configured to allow movement of the shutter from the protection position to the retracted position, by translation, rotation, or helical movement. In the latter case, the helical movement is such as to facilitate the obtaining of a seal between the shutter and the external wall of the enclosure, to limit the risks of fouling of the optical part of this external wall.

In this respect, the flap preferably has a seal at its periphery, pressed against the outer wall of the enclosure when it occupies its protective position.

Whatever the embodiment envisaged, the optical part of the outer wall of the enclosure preferably takes the form of a porthole or a window.

The transparency properties of this optical part are preferably identical or similar to those exposed for the protective film of the first preferred embodiment of the invention.

According to a first preferred embodiment, the measurement equipment comprises a light source arranged outside the enclosure and capable of generating a beam of light along the optical axis, so that this beam of light can irradiate the substrate at characterize in the interior space of the enclosure.

According to a second preferred embodiment, the light source is no longer arranged in the measuring equipment, but formed by the substrate itself, transmitting light to this measuring equipment.

Preferably, the substrate fouling measurement equipment is configured to perform any one of the following measurements:
- a measurement of an electric current generated by the substrate;
- an optical measurement by reflectometry, for example with a spectrophotometer;
- optical measurement in the visible or infrared spectrum, with image processing.

Preferably, the device is configured to carry out a fouling test of a photovoltaic panel, even if the characterization of other types of substrates can be envisaged, such as that of glass panels for example.

The invention also relates to a method for characterizing a substrate in a dirty environment, implemented using a device as described above, the method comprising the following steps:
- generation of messy particles in the enclosure, with the protective member of the optical part of the outer wall of the enclosure occupying its position of protection of the optical part;
- After the messy particles have deposited on the substrate in the interior space of the enclosure, displacement of the protective member from its protective position to its retracted position; Then
- performance of a soiling test of the substrate, using a transmission of light passing through the optical part, between the soiled substrate of dirty particles and the measuring equipment.

In the first preferred embodiment, the substrate fouling test is carried out using a beam of light passing through the optical part, and generated by a light source of the measuring equipment.

In the second preferred embodiment envisaged, the substrate fouling test is carried out using a beam of light generated by the substrate itself.

Other advantages and characteristics of the invention will appear in the non-limiting detailed description below.

This description will be given with regard to the appended drawings, among which;

shows a sectional view of a device for characterizing a substrate in a dirty environment, according to a first preferred embodiment of the invention;

shows a perspective view of the cassette equipping the device shown in the previous figure;

represents the device during a method for characterizing a substrate, according to a preferred embodiment of the invention;

represents the device during the implementation of the method, in a different state;

represents the device during the implementation of the method, in a still different state;

represents the device during the implementation of the method, in a still different state;

is a partial sectional view, showing an alternative embodiment for the cassette of the device;

represents part of the characterization device, according to a second preferred embodiment of the invention;

is a schematic view of an alternative for the second preferred embodiment, with the movable shutter in the protective position;

is a schematic view of the alternative shown in the previous figure, with the movable flap in the retracted position.

DETAILED DISCUSSION OF PARTICULAR EMBODIMENTS

With reference first to the , there is shown a device for characterizing a substrate in a dirty environment, according to a first preferred embodiment of the invention. The characterization device 1 is shown schematically on the . It is provided here to test a substrate 2, which is preferably a photovoltaic panel.

The device 1 is designed to carry out a fouling test of the substrate 2. This test is implemented using an enclosure 4, inside which the natural fouling phenomena are reproduced. To do this, the enclosure 4 comprises an outer wall 6 delimiting an inner space 8, for housing the substrate 2 to be characterised. The interior space 8 is regulated in temperature and humidity by appropriate means 18, making it possible to recreate the natural conditions of the environment in which the substrate is intended to be used.

The outer wall 6 is designed to make the inner space 8 airtight. This wall 6 comprises, integrated into one of its faces, an optical part 10 having properties of transparency. It can be a porthole or even a window, of any shape, for example circular or rectangular. Transparency is desired in relation to the spectrum of the light beam 12 produced by the measuring equipment 14 which will be described below, since this same light beam 12 is intended to pass through the window 10. By way of indication, it is noted that the spectrum of the beam is preferably all or part of the visible spectrum, or possibly of the infrared spectrum depending on the nature of the test carried out.

For example, it is ensured that the window 10 has a transmittance greater than 60% in the spectrum of the light beam 12, this transmittance possibly being of the order of 80%. This transmittance therefore preferably has a high value, with the aim of disturbing as little as possible the light beam 12 supposed to irradiate the substrate 2.

The characterization device 1 also comprises a means 16 making it possible to generate dirty particles in the enclosure 4, such as dust. This means 16 can be placed inside or outside the enclosure. Its design is known to those skilled in the art, which is why it will not be described further.

The characterization device 1 further comprises the measuring equipment 14, the design of which depends on the nature of the fouling test to be carried out.

For example, it may be a measurement of an electric current generated by the substrate 2 irradiated by the light beam 12, itself produced by a light source 20 forming an integral part of the measuring equipment 14 All of this equipment 14 is preferably arranged outside the enclosure 4, with the optical axis 22 of the light beam 12 passing through the porthole 10, as well as the substrate 2 intended to be irradiated by this beam 12 The measurement of the electric current induced by the substrate 2, in the form of a photovoltaic panel, is carried out using a sensor 24 belonging to the measuring equipment 14.

Nevertheless, other types of fouling test can be carried out on the substrate 2, in particular using optical measurements such as those mentioned above (using a spectrophotometer, a flash test, etc. .).

Besides the fact of integrating the measuring equipment 14 into the device 1 close to the enclosure 4, another feature of the invention resides in the implementation of a member 30 for protecting the window 10 against the deposit of dirty particles.

In the first preferred embodiment of the invention, the protective member 30 is formed by a protective film integrated into a cassette 32, which has also been represented on the . On the , the protective film 30 occupies a protective position of the window 10, preferably being in contact with the inner surface of the latter. Indeed, in this position, the protective film 30 arranged inside the enclosure covers the entirety of the window 10, with which it is preferably in contact to prevent messy particles from subsequently being deposited on this window.

Still in this position, the protective film 30 is substantially flat and corresponds to an unrolled part of a roll of film 34, forming an integral part of the cassette 32. Thus, one of the ends of the protective film 30 is connected to the roll 34 formed by a roll of clean film, while the other end of the protective film 30 is connected to a roll of used film 36 of the cassette 32. It is in this roll of used film 36 that the protective film 30, when it moves from its protective position to a retracted position in which it releases the window 10, as will be detailed below. To perform such a displacement of the protective film 30 between these two positions, the device 1 comprises a means of setting in motion 40, designed here to ensure the rotation of an axis 42 around which the roll of film consumed 36 is formed. movement means 40 can incorporate a motor, or a manual rotation system. In the cassette, the two rollers 34, 36 are preferably parallel.

The protective film 30, before its use as a bulwark against the deposition of dirty particles on the window 10 which it covers, also has properties of transparency related to the beam of light 12, since the latter is also intended to pass through the protective film 30. For example, it is ensured that the protective film 30 has a transmittance greater than 60% in the spectrum of the light beam 12, this transmittance possibly being of the order of 80%. Here again, the transmittance retained preferably has a high value, with the aim of disturbing the light beam 12 supposed to irradiate the substrate 2 as little as possible, and also with the same goal of disturbing the signal or the image received by the sensor 24 of the measuring equipment.

It can be a film packaged in a roll and made of PET (polyethylene terephthalate) material, with an antistatic or anti-dirt coating to limit the deposit of dirty particles.

There will now be described a method for characterizing the substrate 2, using the device 1.

First of all, the interior space 8 is regulated in temperature and humidity, using dedicated means 18 coupled to the enclosure 4. Once the temperature and humidity conditions have stabilized, particles are generated messy 44 within the interior space 8, using the means 16. This step, schematized on the , is implemented with the protective film 30 in the protective position of the window 10, to prevent particles 44 from being deposited on the inner surface of this window.

A part of the cloud of particles 44 is then gradually deposited on the surface of the substrate 2 to be tested. Once this deposition has been completed on the substrate 2, the protective film 30 can also be clogged with particles 44, as shown schematically in .

A new step of the method is then implemented, consisting in moving the protective film 30 from its protective position, to its retracted position releasing the window 10. To do this, the moving means 40 is actuated by rotation, so as to simultaneously cause a winding of the used protective film 30 within the roll 36, and an additional unwinding of the roll 34 of clean film. In other words, during this movement, the roll 36 of film consumed gradually integrates the protective film 30 clogged with particles, while the latter gives way, opposite the window 10, to an adjacent unrolled part of the roll 34 , forming another protective film 30' in the protective position for the purposes of another soiling test of a substrate. This state is represented schematically on the .

Finally, the method is continued by carrying out a soiling test of the substrate 2, using the light beam 12 which is activated, as has been schematized on the . During this test, the beam 12 passes through the window 10 and the new protective film 30' of the cassette 32 which covers this window, with the aim of irradiating the substrate 2 clogged with dirty particles 44. Thanks to the electrical signal received in return by the sensor 24, it is possible to characterize the fouling of the substrate 2, here a photovoltaic panel. The test protocol is known as such, implying that its description will not be further detailed.

Concerning this other protective film 30', if it is intended to be crossed by the light beam 12 during the test step which has just been described, its positioning also allows it to be already in place for the protection of the porthole 10 during a new method of characterization of a substrate, identical or different from that present in the interior space 8 of the enclosure 4.

Alternatively, once the fouling test has been carried out, the rollers 34, 36 can move in a direction of rotation opposite to that of the initial removal of the film, in order to allow the re-rolling of the already soiled part on the window. To undergo a new clogging cycle, the portion of clean film is rewound on roller 34 to ensure its protection. This reduces the need for film lengths during characterization.

Referring now to the , there is shown an alternative embodiment for the cassette 32 of the device 1. This cassette 32 incorporates a cleaning means, such as a squeegee 50, making it possible to remove at least some of the soiling particles 44 deposited on the protective film 30. This removal takes place during the displacement of the dirty protective film 30, between its protective position and its retracted position. Indeed, the movement of the protective film 30 implies that the particles 44 which are deposited therein are torn off in turn by the squeegee 50 at the time of their passage in line with the latter, fixed to the body of the cassette 32. The removal of these messy particles 44 makes it possible to rewind the used protective film 36 in a clean, dust-free state, advantageously making it possible to reuse this same film in a reverse direction of operation of the cassette 32, during the implementation of other substrate characterization methods.

Alternatively, the cleaning means 50 can be a brush, a suction means, or any other similar means.

Referring now to the , there is shown a part of a characterization device 1 according to a second preferred embodiment of the invention. This device has many similarities with that of the first embodiment described above, this is the reason why only the differentiating element has been represented. This is the protection member 30, which no longer takes the form of a film, but of a rigid or substantially rigid mobile shutter, mounted on the wall 6 of the enclosure 4 in the interior space 8 The means 40 for setting this flap 30 in motion, between its position protecting the and its retracted position, is here a means allowing rotation along an axis 54 preferably orthogonal locally to the outer wall 6. By manual or motorized rotation of the flap 30, via the means 40, this flap can thus be moved into its position of withdrawal in which it is retracted, then no longer facing the porthole 10. This retracted position is adopted to allow the light beam passing through the porthole 10 to penetrate into the interior space 8, to irradiate the substrate therein find. On the other hand, the protective position of the is adopted during the generation of the cloud of dirty particles, in order to protect the window against the deposit of such particles. A seal 52 is also provided at the periphery of the movable flap 30, and intended to be crushed against the inner surface of the wall 6 when this flap occupies its protective position. This prevents the introduction of dirty particles between the shutter 50 and the window 10, and therefore reduces the risk of particles depositing on the latter.

According to an alternative embodiment, the moving means 40 could be designed to ensure a translational movement of the flap 30 between its two protective and retracted positions. According to yet another alternative shown in Figures 9A and 9B, the moving means 40 could be designed to ensure helical movement of the flap 30 between its two protective and retracted positions, along an axis 56 that is preferentially orthogonal or substantially orthogonal. to the plane of the porthole 10 and to that of the mobile shutter. This helical movement of the flap 30, from its retracted position to its protective position, facilitates the crushing of the seal 52 on the outer wall 6 of the enclosure 4.

Of course, various modifications can be made by those skilled in the art to the invention which has just been described, solely by way of non-limiting examples, and within the limit of the scope defined by the appended claims. In particular, the characteristics associated with the different embodiments can be combined with each other. Furthermore, the invention can be implemented in a similar way with the substrate forming the light source, the measuring equipment then fulfilling the sole function of receiving light, and not that of emitting light.

Claims (17)

Device (1) for characterizing a substrate (2) in a dirty environment, configured to carry out a soiling test of the substrate, the device comprising an enclosure (4) comprising an outer wall (6) delimiting an inner space (8) for housing the substrate to be characterized, as well as a means (16) making it possible to generate messy particles (44) in the enclosure,
characterized in that in that it further comprises equipment (14) for measuring the fouling of the substrate (2), the measuring equipment (14) being arranged outside the enclosure, at least partially opposite an optical part (10) of the outer wall (6), so as to allow transmission of light between the measuring equipment (14) and the substrate (2), along an optical axis (22) passing through the equipment measurement (14), the optical part (10), as well as this substrate (2) to be characterized in the interior space (8),
and in that the device also comprises a member (30) for protecting the optical part (10) of the outer wall (6) of the enclosure against the deposit of dirty particles (44), as well as a means (40 ) for setting in motion the protection member (30) configured to move this member:
- a position for protecting the optical part (10) in which the protective member (30), in the interior space (8) of the enclosure, covers this optical part (10) so as to prevent the deposit thereon of messy particles (44);
- In a retracted position in which the protective member (30) releases the optical part (10) from the outer wall of the enclosure. Device according to Claim 1, characterized in that the protective member is a protective film (30). Device according to claim 2, characterized in that in the protective position, the protective film (30) corresponds to an unwound part of a roll of film (34), and in that the moving means (40) is configured to allow movement of this protective film (30) from the protective position to the removal position, by a further unwinding of the roll of film (34), also causing an adjacent unwound part of the roll to form another film protection (30') occupying the protective position of the optical part (10). Device according to Claim 3, characterized in that it comprises a cassette (32) fitted with the roll of film (34), as well as a roll of used film (36) in which the protective film (30 ) in its retracted position. Device according to Claim 4, characterized in that it comprises cleaning means (50) making it possible to remove at least some of the soiling particles (44) deposited on the protective film (30), during its movement between its position guard and its withdrawn position. Device according to Claim 5, characterized in that the cleaning means (50) is a squeegee, a brush or a suction means. Device according to any one of Claims 2 to 6, characterized in that in the protective position, the protective film (30) is in contact with the outer wall (6) of the enclosure, and preferably in contact with the optical part (10) of this outer wall. Device according to Claim 2, characterized in that the protective member is a flap (30) movable between the protective position and the retracted position. Device according to Claim 8, characterized in that the means for moving (40) is configured to allow the movement of the flap (30) from the protection position to the retracted position, by translation, rotation, or helical movement. Device according to Claim 8 or 9, characterized in that the flap (30) has at its periphery a seal (52), pressed against the outer wall (6) of the enclosure when it occupies its protective position. . Device according to any one of the preceding claims, characterized in that the optical part (10) of the outer wall of the enclosure takes the form of a window. Device according to any one of the preceding claims, characterized in that the measuring equipment (14) comprises a light source (20) arranged outside the enclosure and capable of generating a beam of light (12) according to the optical axis (22), so that this light beam (12) can irradiate the substrate (2) to be characterized in the interior space (8) of the enclosure. Device according to Claim 12 combined with Claim 2, characterized in that the film forming the roll (34) has properties of transparency vis-à-vis the beam of light (12) generated by the light source (20). Device according to any one of the preceding claims, characterized in that the equipment (14) for measuring the fouling of the substrate is configured to carry out any one of the following measurements:
- a measurement of an electric current generated by the substrate;
- an optical measurement by reflectometry, for example with a spectrophotometer;
- optical measurement in the visible or infrared spectrum, with image processing. Device according to any one of the preceding claims, characterized in that it is configured to carry out a fouling test of a photovoltaic panel (2). Method for characterizing a substrate (2) in a dirty environment, implemented using a device (1) according to any one of the preceding claims, the method comprising the following steps:
- generation of dirty particles (44) in the enclosure (4), with the protective member (30) of the optical part (10) of the outer wall of the enclosure occupying its position of protection of the optical part;
- after the soiling particles (44) have been deposited on the substrate (2) in the interior space (8) of the enclosure, displacement of the protective member (30) from its protective position to its protective position withdrawal ; Then
- performance of a soiling test of the substrate (2), using a transmission of light passing through the optical part (10), between the substrate (2) soiled with dirty particles (44) and the equipment measurement (14). Characterization method according to Claim 16, characterized in that the test for soiling of the substrate (2) is carried out using a beam of light (12) passing through the optical part (10), and generated by a light source (20) of the measuring equipment (14).