FR3096454A1 - Installation of optical illumination of a sample and installation of sample analysis and method of managing the optical analysis installation - Google Patents

Abstract

Title: Installation of optical illumination of a sample and installation of the analysis of the sample and method of managing the installation of optical analysis Optical illumination installation (1) for illuminating a sample (4) comprising a laser light source (2) illuminating a deflection mirror (3) pivoting around at least one axis, an optical focusing element (FE) between the source (2) and the mirror (3), a support (5) comprising a wavelength conversion layer (6). The support (5) is transparent for the laser light (L) and/or for the light (LK) converted by the conversion layer (6). The laser light is focused by the optical focusing element (FE), passing through the deflection mirror (3) onto the wavelength conversion layer (6). A projection optic (7) gathers the converted light (LK) on the sample (4) at the focal point (FP) of the projection optic (7). Figure 1

Description

Description Title of the invention: Installation for optical illumination of a sample and installation for the analysis of the sample and method for managing the installation for optical analysis FIELD OF THE INVENTION 100011 The present invention relates to an optical lighting installation for illuminating a sample as well as an optical analysis installation for lighting and analyzing the sample and also a method for managing such an optical analysis installation.

100021 DISCLOSURE AND ADVANTAGES OF THE INVENTION 100031 The subject of the invention is an optical lighting installation for illuminating a sample comprising a laser light source, a deflection mirror illuminated by the laser light source and pivoting around at least an axe ; the optical focusing element between the laser light source and the deflection mirror, and a support having a wavelength conversion layer arranged so that the laser light is directed by the deflection mirror onto the wavelength conversion layer wavelength, the medium being transparent to laser light (and / or to light converted by the wavelength conversion layer, the laser light from the laser light source being focused by the optical focusing element , to pass over the deflection mirror and arrive at the wavelength conversion layer, a projection optic grouping the light converted onto the sample, at the focal point of the projection optic.

The basic idea of the invention is to develop an optical lighting installation to illuminate a sample, and an optical analysis installation to illuminate and analyze the sample and as well as a method for managing the optical analysis installation to improve the spectral image and the corresponding analysis of the sample as an economical alternative to known embodiments, in particular in the near infrared range.

The lighting and analysis installation is advantageously suitable for being integrated into a miniaturized spectrometer.

The use of laser light makes it possible to have high light powers and high resolutions of the region of the sample to be analyzed.

According to the invention, the optical lighting installation used to illuminate a sample comprises a laser light source, a deflection mirror illuminated by the laser light source and pivoting about at least one axis as well as a focusing optical element between the laser light source and the deflection mirror, a support provided with a wavelength conversion layer onto which the laser light is directed by the deflection mirror; the support is transparent to laser light and / or to light 2 converted by the wavelength conversion layer; laser light from the laser light source is focused by the focusing optical element and the reflecting mirror on the wavelength conversion layer and a projection optic gathers the converted light on the sample at the focus of the projection optics.

According to an advantageous development, the optical lighting installation is housed in a housing and the laser light source, the deflection mirror, the support and the projection optics are housed in the housing and / or are integrated In this one.

[0007] According to a preferred development of the optical lighting installation, the laser light source comprises an edge-emitting laser diode or a vertical cavity emitter.

According to a preferred embodiment of the optical lighting installation, the deflection mirror is movable around two axes having different orientations so that the laser light scans a plane of the length conversion layer of wave and thus the focus of the projection optics moves on the sample.

[0009] According to a preferred embodiment of the optical lighting installation, the laser light is converted by the wavelength conversion layer into the near infrared or infrared range.

According to a preferred embodiment of the optical lighting installation, the laser light source and the deflection mirror are installed in modular construction on a circuit board.

[0011] According to a preferred development, the optical lighting installation comprises a control installation and / or a sensor installation which make it possible to adjust and detect at least one deflection angle of the deflection mirror.

According to the invention, the optical analysis installation for illuminating and analyzing a sample comprises an optical lighting installation according to the invention which enables the sample to be illuminated with light having a certain wavelength ; a spectrometer installation which receives the light reflected by the sample and performs a spectral analysis.

The position of the variable focus on the surface of the sample makes it possible to detect a determined region of the surface of the sample and to collect information from the light reflected or transmitted by this region using a spectral analysis.

From the position of the image point and the orientation of the deflection mirror as well as possibly its position, the position of the focus on the sample can be determined.

The analysis installation is carried out in miniature construction and / or integrated into an optical component; miniaturization means that it is a size comparable to the dimensions of a matchbox or smaller.

According to a preferred development of the optical analysis installation, the spectrometer installation 3 and the lighting installation are housed in the same housing and a detection optic is integrated in the housing to deflect the reflected light on the spectrometer installation.

According to a preferred embodiment of the optical analysis installation, the spectrometer installation is a Fabry-Pérot interferometer.

According to a preferred embodiment, the optical analysis installation comprises a control installation for moving the deflection mirror so that the converted light scans with the focus of the projection optics, a certain region of the The sample and the spectrometer setup is controlled to generate a spectrum of the respective point, illuminated by the converted light from the light reflected from the point illuminated by the converted light and from the knowledge of the deflection angle of the illuminating mirror At this point, the position of the point on the sample is identified and with the spectrum of a set of points, a hyperspectral image of the determined region of the sample is generated.

The invention also relates to a method for managing an optical analysis installation for illuminating and analyzing a sample consisting in: providing an optical analysis installation, illuminating the deflection mirror with the laser light of the laser light source, move the deflecting mirror around at least one axis and thereby vary the angle of deflection with respect to the normal to that axis, illuminate the wavelength conversion layer and move the focus by projection optics in a determined region of the sample and receive the light reflected by this determined region and detect the spectrum of the point respectively illuminated by the sample by the spectrometer installation.

According to a preferred embodiment of the method, after detection of the spectrum, knowledge of the position of the point on the sample is used to form a hyperspectral image of the determined region.

According to a preferred embodiment of the method, knowledge of the position of the point on the sample is used to establish a hyperspectral image of the determined region.

According to a characteristic of the method, the knowledge of the position of the point is obtained from the angle of movement of the mirror.

According to a preferred embodiment of the method, the determined region is a surface or a path.

According to a preferred embodiment of the method, the laser light source is modulated as a function of time and the output signal of the spectrometer installation is mixed with a correlation signal and with a correlation method, it is held account of the backlight component in the reflected light, by the correlation method.

Brief description of the drawings

The installation and the method according to the invention (the optical illumination analysis of a sample will be described below with the aid of the accompanying drawings in which:

[0025] [fie.11 schematic side view of an installation (the optical analysis corresponding to an exemplary embodiment of the invention, and

[0026] [fie.21 flowchart of the steps of the method of establishing an interferometer installation according to an exemplary embodiment of the invention.

DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

Figure 1 is a schematic side view of an optical analysis installation according to an exemplary embodiment of the invention.

The optical analysis installation 10 for illuminating and analyzing a sample 4 comprises an optical lighting installation 1 according to the invention.

This installation illuminates a sample 4 with light of a certain wavelength; the installation also comprises a spectrometer installation 20 for receiving the LR light reflected by the sample and performing spectral analysis.

The otic lighting installation 1 for illuminating a sample 4 comprises a laser light source 2, a deflection mirror 3 illuminated by the laser light source 2 and which can rotate about at least one axis; a focusing optical element FE is installed between the laser light source 2 and the deflection mirror 3; a support 5 with a wavelength converting layer 6 is arranged to receive the laser light returned from the reflecting mirror 3; the support 5 is transparent for the laser light L and / or for the converted light LK supplied by the length conversion installation 6; the laser light from the laser light source 2 is focused by the focusing optical element FE and returned by the reflecting mirror 3 to the wavelength converting layer 6; a projection optic 7 gathers the converted light LK at the focal point FP of the projection optics 7 on the sample 4.

The laser light from the laser light source 2 may be partially focused on the wavelength conversion layer 6, that is to say have a macroscopic extension at the BP image point or be precisely focused at the focal point of the focusing optical element FE.

On the other hand, advantageously, the light from each point of the wavelength conversion layer 6 is grouped together precisely at the focal point FP on the sample 4.

The BP image dot has, for example, a diameter of less than 100 Rna and thus it advantageously acts as a very small, broadband, low-area light source.

The lighting installation 1 comprises a housing 8 and the laser light source 2, the deflection mirror 3, the support 5 and the projection optics 7 are housed in the housing 8 and / or are integrated in this one.

The analysis installation 10 can be housed in the same housing with the lighting installation 1 and detection optics 11 (such as a photodiode) can be integrated into the housing 8; this optic makes it possible to direct the reflected light LR onto the spectrometer installation 20.

The analysis installation 10 may however comprise several components constituting different zones in space, for example, so that the sample is placed between the lighting installation and the spectrometer installation to allow the measurement of the spectrometer. light transmitted through the sample (this variant is not shown).

The light reflected (scattered) by the surface of the sample (or which will have partially penetrated into the material of the sample) or the transmitted light, may after the absorption of certain wavelengths of absorption characteristics of the sample material (absorption characteristic of the chemical structure) has a spectral signature.

This light is detected using the spectrometer installation which detects the absorption wavelengths to thus obtain information concerning the composition of the sample if the spectral image obtained (absorption spectrum ) of each point or only by region of the sample surface can be analyzed with known absorption spectra, for example by a chi miometric analysis and comparison with a database.

By detecting the sample with light of known wavelength, at a local point (focus) in a determined region and displacement of the point on the determined surface then analysis of the light reflected or transmitted by this point, it is possible forming a hyperspectral spectral image of the sample by associating the information obtained at each respective point of the sample.

The spectrometer installation 20 can be a one-point spectrometer such as a Fabry-Perot interferometer (FPI).

The light reflected by the sample 4 in the spectrometer installation 20 is detected by a single photodiode; the spectrometer installation comprises a photodiode 11 downstream of the FPI spectrometer.

The detection of the light reflected by the sample 4 can be tuned and synchronized with the movement of the deflection mirror in an advantageous manner by the control installation SE.

Thus, a two-dimensional spectral map of sample 4 can then be established sequentially.

It is further possible to combine a conventional image of sample 4 (such as an image from an imaging camera) with the spectral map and combine further analysis with image recognition algorithms.

The field of view (FOV) of the spectrometer installation 20, for example, the objective of the spectrometer installation 20 is advantageously as large as the entire desired two-dimensional range of motion at one or two dimensions, desired from the field of view. FP fireplace.

The movement of the focus is along a path or on a surface of the sample.

The variable position focus on the sample surface scans a determined region of the sample surface and information is collected from the light reflected or transmitted in that region by applying spectral analysis.

From the position of the BP image point and the orientation of the deflection mirror as well as, where appropriate, from its position, the position of the focal point FP on the sample can be determined.

In addition, from the knowledge of the position of the deflection mirror, that is to say of its angle with respect to the normal to its axis of movement and of the angle of incidence in the sample or in the spectrometer installation, the position of the focus FP on the sample 4 is determined.

As a result, the movement makes it possible to do dot-to-dot screening.

If this screening is done on a path, it can have different shapes.

Two-dimensional screening (such as the movement of the deflecting mirror in two dimensions / two angles or the movement of the entire analysis set-up) enables line-by-line and point-to-point detection.

The path can also have a circular shape or more generally a rounded shape.

This makes it possible to capture control samples in segments along the circular path, for example, for sample inhomogeneities and to avoid rasterization of the entire surface.

This significantly reduces the time required for analysis.

The spectrometer installation can be implemented in the form of a microspectrometer.

This makes it possible to integrate it into household appliances, for example, to analyze milk or in other applications.

The wavelength conversion layer 6 makes it possible to generate, for example light by fluorescence and comprises at least one phosphor which will be excited by the laser light for broadband emission.

The laser light source 2 can be an edge emission laser diode or a vertical cavity emitter (VCSEL).

The laser light source 2 advantageously designed to allow very efficient conversion of the wavelength by the material of the wavelength conversion layer 6.

[0041] The deflection mirror 3 can be movable around two axes with different orientations so that the laser light beam L makes it possible to scan the plane of the wavelength conversion layer 6 and thus to move the focal point FP of the projection optics 7 on the sample 4.

This allows a two-dimensional range of the sample to be swept.

The laser light L is converted by the wavelength converting layer 6 into light in the near infrared or infrared range, preferably by the converting layer 6.

The wavelength conversion layer 6 may consist of several layers and / or a conversion plate.

The focus FP is the point conjugate of the image point BP. 7

The laser light source 1 and the deflection mirror 3 are made in modular construction on a circuit board 9.

The circuit board is a printed circuit board (PCB board) with conductive paths.

The support 5 can include a glass plate.

The glass plate or the support includes a filter; the filter can also be installed or disposed on the plate to advantageously convert the light.

Instead of the filter on the support, it is also possible to use a projection optical lens 7 with a filter, such as a lens made of a suitable filter material.

After absorption by sample 4, the converted and reflected light is transmitted to the spectrometer module and makes it possible to obtain the absorption spectrum characteristic of the desired material.

Figure 1 shows a first region of the circuit board 9 at the bottom of the housing 8 and a second region of the circuit board 9 on the side wall of the housing 8.

The two regions of the circuit board are connected by contact wires.

In the example of figure 1, the laser light source 2 is on the second region of the circuit board 9 on the side wall and at a certain height above the bottom of the housing 8 and it radiates into a cavity K1 which includes the laser light source 2, the deflection mirror 3 and the holder 5.

The deflection mirror 3 is installed on a base 3a in the first region of the circuit board 9 while being advantageously pivotable.

Figure 1 only shows the possible pivoting at an angle, but in reality one can have pivoting movements at several angles.

The base 3a comprises an SE control installation and / or an SN sensor installation which adjusts at least one deflection angle of the deflection mirror and makes it possible to detect it.

The spectrometer installation 20 is shown schematically in Figure 1 in the form of a region of the housing 8.

The focusing optical element FE can be installed on the laser light source 2, advantageously in the emission range of the laser light source 2 and the light L from the source 2 will be focused along a cone (focusing forming a beam) the illumination point of which is, for example, the focus directed at the surface of the wavelength conversion layer 6.

This wavelength conversion layer 6 is applied to the support 5 on the side facing the deflection mirror 3 and / or on the opposite side (in the case of a second wavelength conversion layer) .

The FE focusing optical element is a lens or a difracting element (DOE).

The laser light source 2 can be modulated as a function of time and the output signal of the spectrometer installation 20 (on a detector) can be mixed with a correlation signal (for example a recorded correlation signal or generated in a control installation or an operating installation) and makes it possible to take into account the background light component of the reflected light LR by a correlation process.

This modulation can be done in the frequency range Hz, kHz or 8 MHz.

The photodetector can be read by a correlation method, for example, it can be read by the look-in method.

This effectively eliminates the extraneous light not coming from the laser light source 2, in other words, before establishing the spectral information.

In this case, the field of view of the spectrometer installation can correspond to the entire image range of sample 4, that is to say to the entire range to be received, advantageously of the entire sample. 4.

Operation with the correlation method advantageously generates an overall image of the sample with a better signal / noise ratio.

The return of the laser beam by the deflection mirror 3 only in one dimension makes it possible to collect information in a second dimension by the movement of the assembly of the lighting installation 1 and / or of the assembly of the optical analysis installation 10 in the other dimension, for example, in the dimension perpendicular to the deflection direction (in the same plane of the sample 4) of the deflection mirror 3 (the process is known under the name Anglo-Saxon "Pushbroom-scanning").

FIG. 2 is a block diagram of a flowchart of the method for establishing an interferometer installation according to an exemplary embodiment of the invention.

In the method of managing an optical analysis installation for illuminating and analyzing a sample, the steps consist in providing (Si) an optical analysis installation, in illuminating (S2) the deflection mirror with light laser of the light source, in moving (S3) the deflection mirror around at least one axis and by varying the deflection angle with respect to the normal to this axis, then in illuminating (S4) the conversion layer of wavelength and moving the focus of the projection optics in a determined region of the sample; then collect (S5) the light reflected by the determined region and detect (S6) the spectrum of the respective point illuminated of the sample by the spectrometer installation.

[0050] NOMENCLATURE OF THE MAIN ELEMENTS

[0051] 1 Optical lighting installation

2 Laser light source

[0053] 3 Deflection mirror

[0054] 4 Sample

[0055] 5 Support

6 Uncle length conversion layer

[0057] 7 Projection optics

8 Housing

[0059] 10 Optical analysis installation

[0060] Installation of spectrometer

[0061] FP Foyer

FPI Fabry-Perot interferometer

LK Converted light

[0064] LR Reflected light

[0065] P Illuminated point

[0066] SE Control installation

[0067] SN Sensor installation

51-56 Steps of the process for managing an analysis installation

[0069] optical [Claim 1] [Claim 2]

Claims (1)

Optical illumination installation (1) for illuminating a sample (4) comprising: a laser light source (2), a deflection mirror (3) illuminated by the laser light source (2) and pivoting around at least an axis, an optical focusing element (FE) between the laser light source (2) and the deflection mirror (3), a support (5) having a wavelength conversion layer (6) arranged so that the laser light is directed by the deflection mirror (3) onto the wavelength conversion layer, the support (5) being transparent to the laser light (L) and / or to the light (LK) converted by the wavelength layer. wavelength conversion (6), the laser light from the laser light source (2) being focused by the optical focusing element (FE), passing through the deflection mirror (3) on the conversion layer wavelength (6), and a projection optic (7) which groups the converted light (LK) on the sample (4) at the focal point (FP) of the projection optics (7). Optical lighting installation (1) according to claim 1, comprising [Claim 3] [Claim 4] [Claim 5] a housing (8), in which are housed and / or integrated the laser light source (2), the deflector mirror (3), support (5) and projection optics (7). Optical lighting installation (1) according to claim 1 or 2, wherein the laser light source (2) comprises an edge emitting laser diode or a vertical cavity emitter (VCSEL). Optical lighting installation (1) according to one of claims 1 to 3, according to which the deflection mirror (3) is movable about two axes oriented differently so that the laser light (L) can scan a plane of the wavelength conversion layer (6) and thus the focus (FP) of the projection optics (7) moves on the sample (4). Optical lighting installation (1) according to one of claims 1 to 4, wherein the laser light (L) is converted by the conversion layer of 11 [Claim 6] [Claim 7] [Claim 8] [Claim 9 ] [Claim 10] [Claim 11] wavelength (6) in a near infrared or infrared wavelength range. Optical lighting installation (1) according to one of claims 1 to 5, according to which the laser light source (1) and the deflection mirror (3) are mounted in modular construction on a circuit board (9). Optical lighting installation (1) according to one of claims 1 to 6, comprising: a control installation (SE) and / or a sensor installation (SN) which make it possible to adjust and detect at least one deflection angle of the deflector mirror. Optical analysis installation (10) for illuminating and analyzing a sample (4) comprising: an optical lighting installation (1) according to one of claims 1 to 7 which enables the sample (4) to be illuminated with a light having a determined wavelength, and a spectrometer installation (20) which receives and performs a spectral analysis of the reflected light (LR) of the sample (4). Optical analysis installation (10) according to claim 8 attached to claim 2, according to which the spectrometer installation (20) and the lighting installation (1) are housed in the same housing (8) and in which Integrated detection optics (11) direct the reflected light (LR) onto the spectrometer installation (20). Optical analysis installation (10) according to claim 8 or 9, in which the spectrometer installation (20) comprises a Fabry-Perot interferometer (FPI). Optical analysis installation (10) according to one of claims 8 to 10, which comprises a control installation (SE) for moving the deflection mirror (3) so that the converted light (LK) arriving at the focal point of the lens. The projection optics (7) travels over a determined range of the sample (4), and the spectrometer installation (20) is controlled to generate a spectrum of light reflected (LR) by the point (P) illuminated by the converted light (LK), and from the knowledge of at least one deflection angle of the deflection mirror (3) set to illuminate this point, the position of the point (P) on the sample (4) is identified and from the spectra of a large number of points, a hyperspectral image of the defined region of the sample (4) is generated. [Claim 12] A method of managing an optical analysis installation (10) for illuminating and analyzing a sample (4) comprising the steps of [Claim 13] [Claim 14] [Claim 15] [Claim 16] providing ( S1) an optical analysis installation (10) according to one of claims 8 to 11, illuminate (S2) the deflection mirror (3) with laser light from the laser light source (1), move (S3) the deflection mirror (3) around at least one axis and thus vary at least the deflection angle with respect to the normal to this axis, illuminate (S4) the wavelength conversion layer (6) and moving the focal point of the projection optic (7) in a determined region of the sample (4), and receiving (S5) the light (LR) reflected by this determined region, and detecting (S6) the spectrum of the point (P) respectively illuminated sample (4) by the spectrometer installation (20). Method according to claim 12, wherein the detection (S5) of the spectrum uses the knowledge of the position of the point (P) on the sample (4) to establish a hyperspectral image of the determined region. Method according to Claim 13, according to which the knowledge of the position of the point (P) is determined by the respective deflection angle of the deflection mirror. Method according to one of claims 12 to 14, wherein the determined region comprises a surface or a path. Method according to one of Claims 12 to 15, according to which the laser light source (1) is modulated in time, the output signal of the spectrometer installation (20) is mixed with a correlation signal and by a The correlation method takes into account the backlight component of the reflected light (LR).