MULTISPECTRAL REFLECTIVE IMAGING DEVICE

Abstract

Imaging device (100) configured to image a sample (102), comprising: - a light source (104) emitting light; - a light deflection device configured to deflect the light emitted by the light source towards the sample, comprising a portion of material (106) having a first main face (108) disposed opposite the sample (102), a second main face (110), and a first lateral face (112) towards which the light is emitted by the light source; - an imager (118) having a detection face (122) disposed opposite the second main face and intended to receive the light backscattered by the sample; in which one of the main faces has oblique parts (114) each configured to deflect a part of the light received towards the sample (102), and flat parts (116) configured to let the light backscattered by the sample pass through.Figure for the abbreviation: figure 1.

Description

Title of the invention: MULTI-PECTRAL REFLECTION IMAGING DEVICE Technical field

[0001] The invention relates to the field of imaging, in particular multi-spectral reflection imaging, in the visible and / or infrared (IR) range. The invention can advantageously be used for the analysis of microorganisms, cells, biological tissues, or for the diagnosis of diseases. Prior art

[0002] In order to obtain an image of a biological sample to be analyzed, one solution is to map the sample using a microscope coupled with a polychromatic IR source and a Fourier transform IR spectrometer, or FTIR (Fourier-transform infrared spectroscopy). Such a system allows the sample to be scanned and multispectral images to be obtained. One drawback of this type of solution is that analyzing a sample area of ​​a few square centimeters is time-consuming due to the millions of spectra obtained and the resulting large datasets that need to be processed. Furthermore, such a system is complex, expensive, and bulky.

[0003] The emergence of quantum cascade lasers, or QCLs (acronym for "Quantum Cascade Laser"), makes it possible to create a plurality of monochromatic IR sources that together cover the spectral range of a polychromatic IR source. With such laser light sources, it is no longer necessary to use an FTIR spectrometer to spectrally analyze the light that has interacted with the sample. A detector sensitive in 1TR is sufficient to quantify the intensity of the light transmitted or scattered by the sample, for each of the wavelengths chosen as relevant for the analysis.

[0004] Another constraint is that multispectral IR imaging developed in transmission does not allow for the biochemical mapping of thick samples, due in particular to the strong light absorption by the water present in biological samples. In order to overcome this absorption, IR reflection spectrometry has been developed using the phenomenon of attenuated total reflectance, or ATR. This requires placing the measurement system as close as possible to the sample. However, this method has two major drawbacks: - the low penetration of evanescent waves into the sample, requiring the sample to be positioned as close as possible to the measurement system; - the small field of view of the imaged object.

[0005] To overcome these drawbacks, document FR 3 110 979 Al proposes a chip with a deflector array matrix. However, this type of chip has the following disadvantages: - limited spectral band; - complex construction of deflector networks; - masking of bolometers placed under deflector networks.

[0006] An alternative solution is described in document EP 3916 441 A1, which proposes fabricating a chip from an etched silicon substrate to allow the entry of a laser beam from the side of the substrate facing the bolometer array used as a sensor. However, this chip has the following drawbacks: - significant bulk; - excessive absorption of light by silicon; - complexity of injecting light into the chip. Description of the invention

[0007] An object of the present invention is to propose a multi-pectral reflection imaging device equipped with an optical system that does not have the disadvantages described above.

[0008] To this end, the present invention proposes an imaging device configured to image a sample, comprising at least: - a first light source configured to emit light; - a light deflection device configured to deflect the light intended to be emitted by the first light source towards the sample, comprising a portion of material having a first main face intended to be positioned opposite the sample, a second main face opposite the first main face, and a first lateral face towards which the light is intended to be emitted by the first light source; - an imager comprising a plurality of pixels and having a detection face arranged opposite the second main face of the light deflection device and intended to receive the light backscattered by the sample;

[0009] characterized in that one of the first and second main faces has parts oblique to the other of the first and second main faces and each configured to deflect a part of the light received towards the sample, and of flat parts parallel to the other of the first and second main faces and configured to let the light backscattered by the sample pass through.

[0010] In this imaging device, light is first emitted at least by the first light source on the side of the first lateral face of the portion of The light is then deflected by the oblique parts of one of the first and second principal faces (which correspond to the two largest faces) of the material portion towards the sample. After reaching and interacting with the sample, the light is backscattered by the sample, passes through the material portion via the flat parts of one of the first and second principal faces and the other of the first and second principal faces of the material portion, and is then captured by the imager to obtain an image of the sample at the wavelengths of the light emitted by the first light source.

[0011] Unlike the imaging device with a deflector array matrix, the imaging device proposed here uses a light deflection device that is less complex to make and adapted to deflect light over a larger spectral band because the light deflection occurs thanks to the geometry of the portion of material of the light deflection device, namely the oblique parts of the portion of material.

[0012] Furthermore, the structure formed by the succession of oblique and flat parts on one of the main faces of the light deflection device can be easily produced with a small footprint, without significant light absorption. Moreover, light deflection is achieved simply by illuminating the light deflection device laterally.

[0013] With the proposed imaging device, the above advantages are obtained while maintaining a large field of view and a spatial resolution corresponding to the resolution of the imager.

[0014] With the proposed imaging device, it is possible, for example, to guide and multiplex mid-infrared (MIR) wavelengths between 5 pm and 10 pm, or between 6 pm and 9 pm, representing a bandwidth of approximately 1000 cm¹ in wavenumber. This represents a significant advantage over optical waveguides, which are generally designed to be single-mode in order to perform their functions. For example, conventional multiplexers of the "Array Waveguide Gratings" (AWG) type cover a spectral operating range of only about 100 cm¹ in terms of wavenumber.

[0015] The proposed imaging device also makes it possible to illuminate homogeneously an area with a surface area greater than 2.5 mm2, for example on the order of 3 x 3 mm2, and to be able to collect the photons reflected by the object on such a surface.

[0016] The imaging device can be made in the form of a photonic integrated circuit, or PIC (“Photonic Integrated Circuit” in English) in which the light deflection device sends the light onto the sample and not onto the imager.

[0017] Another advantage is that this imaging device is thermally stable.

[0018] In the proposed imaging device, the light deflection device is inserted between the matrix imager and the sample. The light deflection device acts as a deflector with respect to the light received laterally and emitted from at least the first light source, and also acts as an optical flux distributor with respect to the light backscattered by the sample.

[0019] The light deflection device has a generally planar shape, and one of its principal faces is structured in a stepped or rung pattern. By "step-like structure," we mean that one of the principal faces of the light deflection device has a succession of steps with oblique sides, each of which redirects a certain fraction of the incident flux toward the sample. The light deflection device can be viewed as forming a "discretized" parabolic mirror.

[0020] The size and number of steps, each formed by an oblique part and a flat part close to each other, can be determined according to the architecture of the imager (which may include a matrix of photodetectors operating in the visible and / or infrared range, based on semiconductors or on micro-bolometers for example) and the desired homogeneity of illumination for the sample analyzed.

[0021] The portion of material in the light deflection device comprises a material with low absorption with respect to the range of wavelengths of light emitted by the first light source. For example, if the length of the portion of material is 1 cm, to obtain a light attenuation of at most 10%, the material can be chosen such that the imaginary part of its refractive index is less than 10⁴ when considering wavelengths in the visible and infrared ranges.

[0022] Each of the first and second principal faces of the material portion of the light deflection device can have dimensions on the order of one or more mm², and the thickness (dimension perpendicular to the principal face that does not include the oblique parts) of the material portion of the light deflection device can be equal to one or more hundred microns, or less than 1 mm. Such a geometry is well suited to the principle of lensless imaging in which the device is very close to the imaged sample.

[0023] The imaging device can be configured so that the imager can be positioned at a distance from the sample of less than 1 mm.

[0024] Each pixel of the imager has at least one photodetector.

[0025] In a first embodiment, the imaging device can be such that: - said one of the first and second main faces (the one with the oblique parts and the flat parts) corresponds to the second main face (the one arranged opposite the imager); - the light intended to be emitted by the first light source is intended to enter the portion of material of the light deflection device through the first lateral face; - the portion of material of the light deflection device comprises a material whose refractive index ni is greater than the refractive index n2 of the medium in which said portion of material is located.

[0026] In this first embodiment, the oblique parts achieve a light deflection by total internal reflection of the light entered into the portion of material of the light deflection device, each oblique part reflecting back a fraction of the light beam entered laterally in the direction of the sample.

[0027] In this first embodiment, the device may further include a collimator interposed between the first light source and the first lateral face of the light deflection device. This collimator makes the light emitted by the first light source homogenized along the cross-section of the light deflection device, thus allowing a relatively uniform deflection of the light flux towards the sample.

[0028] In a second embodiment, the imaging device can be such that: - said one of the first and second main faces (the one with the oblique parts and the flat parts) corresponds to the first main face (the one positioned opposite the imager); - the portion of material of the light deflection device comprises a material whose refractive index ni is greater than the refractive index n2 of the medium in which said portion of material is located; - the oblique parts of said first and second main faces are covered with a material that is reflective with respect to the light intended to be emitted by the first light source.

[0029] In this second embodiment, the light deflection corresponds to an external reflection occurring outside the portion of material, on the oblique parts covered by the reflective material. An advantage of this second embodiment is that the light beam does not have to be directed into the portion of material of the light deflection device.

[0030] The reflective material can be totally reflective, that is to say, reflect all the light arriving on the material.

[0031] According to an example of an embodiment applicable to the first or second embodiment, the oblique parts of said one of the first and second principal faces can form parallel bands spaced from each other by the flat parts.

[0032] According to another embodiment applicable to the first or second mode of In construction, the oblique parts can be arranged in a staggered pattern and spaced apart from each other by the flat parts.

[0033] According to another embodiment applicable to the first or second embodiment, the oblique parts can form concentric circles or concentric rectangles spaced apart from each other by the flat parts.

[0034] The device may further comprise a second light source configured to emit light similar to that emitted by the first light source, wherein the portion of material has a second lateral face opposite to the first lateral face and towards which the second light source is intended to emit its light, and wherein the portion of material is symmetrical with respect to a plane perpendicular to the other of the first and second main faces.The advantage of such a configuration (applicable to the first or second embodiment) is that for the same surface area of ​​the first and second principal faces, the thickness of the portion of material can be reduced because oblique parts reflecting the light emitted from the first light source are in planes similar to oblique parts reflecting the light emitted from the second light source, these planes being parallel to each other of the first and second principal faces.

[0035] The portion of material may comprise at least one of the following materials, which are particularly suitable for infrared: germanium, undoped silicon, ZnSe, ZnS, chalcogenide glass, CaF2.

[0036] The flat portions of said first and second principal faces and / or the other first and second principal faces may be coated with an anti-reflective material. This configuration improves the light transmission of the backscattered light from the sample to the imager by preventing unwanted light reflections due to changes in refractive index between the material of the sample portion and the medium in which the sample portion is located, along the path of the light from the sample to the imager. This configuration ultimately improves the efficiency of the device.

[0037] Each pixel of the imager can be positioned opposite one of the flat portions of said first and second principal faces. This configuration is advantageous because the flat portions present little obstacle to the transmission of the signal to the imager.

[0038] In a particular configuration, the oblique parts can be curved, which can, for example, allow the light to be deflected over a wider angular cone than when the oblique parts are uncurved, and thus further homogenize the illumination of the sample.

[0039] The first light source can be configured to emit a light including several wavelengths in the visible and / or infrared range.

[0040] The invention also relates to a method for making an imaging device configured to image a sample, comprising at least: - provision of a first light source configured to emit light; - realization of a light deflection device configured to deflect the light intended to be emitted by the first light source towards the sample, comprising a portion of material having a first main face intended to be positioned opposite the sample, a second main face opposite the first main face, and a first lateral face towards which the light is intended to be emitted by the first light source; - provision of an imager comprising a plurality of pixels and having a detection face arranged opposite the second main face and intended to receive the light backscattered by the sample;

[0041] characterized in that the embodiment of the light deflection device includes the making, at the level of one of the first and second main faces, of parts oblique with respect to the other of the first and second main faces and each configured to deflect a part of the light received towards the sample, and of flat parts parallel to the other of the first and second main faces and configured to let the light backscattered by the sample pass through.

[0042] The production of the oblique and flat parts of the portion of material of the light deflection device may involve the implementation of laser engraving of the portion of material.

[0043] Throughout this document, the term "on" is used without distinction as to the spatial orientation of the element to which it refers. For example, in the feature "on a face," this face is not necessarily oriented upwards but may correspond to a face oriented in any direction. Furthermore, the arrangement of a first element on a second element should be understood as either having the first element directly against the second element, without any intermediate elements between the first and second elements, or having the first element on the second element with one or more intermediate elements arranged between the first and second elements. Brief description of the drawings

[0044] The present invention will be better understood upon reading the description of exemplary embodiments given by way of illustration only and in no way limiting, with reference to the accompanying drawings in which:

[0045] [Fig. 1] schematically represents an imaging device, the subject of the present invention, according to a first embodiment;

[0046] [Fig.2] schematically represents, in top view, the imaging device, the object of the present invention, according to the first embodiment;

[0047] [Fig.3] schematically represents part of an imaging device, the subject of the present invention, according to a second embodiment;

[0048] [Fig.4]

[0049] [Fig.5]

[0050] [Fig.6], and

[0051] [Fig.7] schematically represent part of an imaging device, the subject of the present invention, according to different variants.

[0052] Identical, similar or equivalent parts of the different figures described below bear the same numerical references so as to facilitate the transition from one figure to another.

[0053] The different parts represented in the figures are not necessarily shown on a uniform scale, in order to make the figures more legible.

[0054] The different possibilities (variants and embodiments) should be understood as not being mutually exclusive and can be combined with each other.

[0055] Detailed description of particular embodiments

[0056] An imaging device 100 according to a first embodiment and configured to image a sample 102, for example a biological tissue such as skin, is described below in relation to figures 1 and 2.

[0057] The device 100 comprises at least one first light source 104 configured to emit light. In the example described here, the light emitted by the first light source 104 comprises several wavelengths in the visible and / or infrared range. Advantageously, the first light source 104 is capable of emitting light comprising wavelengths in the mid-infrared (MIR) range, covering in particular a wavelength range between 5 pm and 10 pm, or between 6 pm and 9 pm. Furthermore, according to an advantageous embodiment, the first light source 104 may include at least one QCL-type laser emitting element.

[0058] The device 100 also includes a light deflection device configured to deflect the light intended to be emitted by the first light source 104 towards the sample 102. The light deflection device comprises a portion 106 of material having a first main face 108 intended to be positioned opposite the sample 102, a second main face 110 opposite the first main face 108, and a first lateral face 112 towards which the light is intended to be emitted by the first light source 104. The material of the portion 106 is such that it absorbs little or no light over the scale of the portion 106 (which may be several mm in the longitudinal direction, i.e., along the visible X or Y axis). on [Fig.1]). For example, when the device 100 includes a first light source 104 emitting light in the infrared range, the material of the portion 106 corresponds for example to germanium, undoped silicon, ZnSe, ZnS, chalcogenide glass, CaF2, etc.

[0059] One of the first and second principal faces 108, 110 of the portion 106 is provided with oblique sections 114, each configured to deflect a portion of the received light towards the sample 102. In the embodiment described with reference to Figures 1 and 2, said one of the first and second principal faces 108, 110 corresponds to the second principal face 110. As can be seen in [Fig. 1], the light emitted from the first light source 104 is represented by an arrow and enters the portion 106 through the first lateral face 112. This light propagates through the entire thickness of the portion 106. The rays of this light, upon encountering the oblique sections 114, are deflected from their path, pass through the first principal face 108, and illuminate the sample 102.

[0060] Advantageously, the light emitted by the first light source 104 and received by the portion 106 through its first lateral face 112 is collimated so that it propagates in a direction substantially parallel to the first main face 108. Furthermore, the light flux preferably enters the portion 106 homogeneously along the cross-section of the portion 106, i.e. over the entire first lateral face 112, in order to obtain a relatively uniform deflection of the light flux towards the sample 102. Such collimated light propagating uniformly in the portion 106 is obtained, for example, by optically coupling the output of the light source 104 to the first lateral face 112 with a collimator 111, for example a spherical lens.

[0061] In the configuration described here, the light deflection by the oblique parts 114 is obtained by total internal reflection, this phenomenon occurring when: - portion 116 comprises a material whose refractive index ni is greater than the refractive index n2 of the medium in which portion 116 is located, this medium being, for example, air, and - The angle α, shown in [Fig. 1], formed by the oblique parts 114 with respect to the direction of propagation of the light entering the portion 116, is such that α < μr / 2 - arcsin(n2 / nl). More precisely, in order to also avoid any total internal reflection at the level of face 108, the angle α will advantageously satisfy the following framing formula: μr / 2 - arcsin(n2 / nl) < 2α < μr / 2 + arcsin(n2 / nl).

[0062] By way of example, the material of portion 106 can be chosen such that its refractive index ni is greater than 2 or 3. Thus, considering that the material of portion 106 has an optical index ni = 3.5, and that portion 106 is surrounded by air (optical index n2 = 1), the oblique parts 114 are formed such that the angle obtained is less than 73°, of Preference between 37° and 53°. The value of this angle can be advantageously chosen as being equal to or close to 45°, which allows obtaining a light deflection that is substantially perpendicular to the surface of the sample 102 intended to be illuminated.

[0063] The main face with the oblique portions 114, i.e., the second main face 110 in the first embodiment, also has flat portions 116 parallel to the other of the first and second main faces 108, 110 (i.e., to the first main face 108 in the first embodiment described here) and configured to allow light backscattered by the sample 102 to pass through. In the example in [Fig. 1], this backscattered light is represented by dashed arrows. Thus, this light backscattered by the sample 102 passes through the portion 106 via the first main face 108 and the flat portions 116.The backscattered light arriving at the oblique parts 114 either passes through the oblique parts 114, or is obliquely reflected and returns to the optical guide by internal reflection, or partially re-illuminates the sample (this portion being, however, minor compared to the overall illumination flux). The flat parts 116 can be seen as distributing the optical flux backscattered by the sample 102.

[0064] The portion 106 has overall a planar shape extending in the (X, Y) plane visible in figures 1 and 2. The oblique parts 114 and planar parts 116 form a stair-step (or rung) structure of one of the principal faces 108, 110 of the portion 106. The planar parts 116 are parallel to the opposite principal face, here face 108.

[0065] The device 100 further comprises an imager 118 configured to detect light after it has been backscattered by the sample 102 and has passed through the portion 106. The imager 118 comprises a plurality of pixels 120 corresponding, for example, to microbolometers or semiconductor-based photodetectors. These pixels 120 are located on a detection face 122 of the imager 118, which is positioned opposite the second principal face 110 of the portion 106. In the embodiment described here, the pixels 120 are distributed on the detection face 122 of the imager 118 in the form of a matrix. Furthermore, each pixel 120 of the imager 118 is advantageously positioned opposite one of the flat parts 116 so that all the pixels 120 receive backscattered light from the sample 102.As an example, the 118 imager can have an 80x80 pixel matrix with a pitch of 34 pm (therefore with pixels of side equal to 24 pm, and inter-pixel spaces each equal to 9 pm), i.e. an active area of ​​2.7 x 2.7 mm2. .

[0066] According to one embodiment of the device 100, the oblique parts 114 form parallel bands spaced apart from each other by the flat parts 116. Such configuration is visible on [Fig.2] which schematically represents a top view of device 100. On this [Fig.2], the pixels 120 of the imager 118 arranged under portion 106 are shown in order to better understand the arrangement of the oblique parts 114 and the flat parts 116 of portion 106 with respect to these pixels 120.

[0067] When using the device 100, the imager 118 is advantageously positioned at a distance d from the sample 102 that is less than 1 mm. The thickness (dimension parallel to the Z-axis in Figures 1 and 2) of the portion 106 is therefore advantageously less than this dimension d, and thus less than 1 mm. For example, considering the imager 118 described above, a deflector comprising a linear flank with an oblicit angle of 45° positioned opposite each inter-pixel column can have a thickness on the order of 79 x 9 = 711 pm.

[0068] In the example shown in Figures 1 and 2, only three oblique parts 114 are shown. However, the size and number of oblique parts 114 in one of the first and second principal faces 108, 110 of the portion 106 is calibrated according to the architecture of the imager 118 and the desired illumination homogeneity for the analyzed sample 102.

[0069] An imaging device 100 according to a second embodiment is described below in relation to [Fig.3].

[0070] In this second embodiment, the face of the portion 106 comprising the oblique parts 114 and the flat parts 116 corresponds to the first main face 108. The portion 106 comprises a material whose refractive index ni is greater than the refractive index n2 of the medium in which the portion 106 is located. Finally, the oblique parts 114 are covered with a material that is reflective with respect to the light intended to be emitted by the light source 104, for example a metallic material.

[0071] As in the first embodiment, each pixel 120 of the imager 118 is advantageously arranged opposite one of the flat parts 116 so that all the pixels 120 receive backscattered light from the sample 102.

[0072] In this second embodiment, the light deflection by the oblique portions 114 is obtained by reflection on the external surface of the portion 106, and not by total internal reflection as in the first embodiment. Thus, the material of the portion 106 is preferably chosen such that its optical index is low in order to best transmit the light backscattered by the sample 102 to the imager 118, and the oblique portions 114 are covered with an optically reflective material in order to reflect the light back to the sample 102.

[0073] The various examples and variants previously described for the first embodiment can also be applied to the second embodiment.

[0074] An imaging device 100 according to a variant of the first embodiment is described below in relation to [Fig.4].

[0075] In this embodiment, the device 100 further comprises a second light source 124 configured to emit light similar to that emitted by the first light source 104. The portion 106 has a second lateral face 126 opposite the first lateral face 112, towards which the second light source 124 is intended to emit its light. Moreover, the portion 106 is symmetrical with respect to a plane perpendicular to the first main face 108 (plane P in [Fig. 4]). Bilateral illumination of the portion 106 is achieved by the first and second light sources 104, 124. This has the advantage, for the same light deflection, of allowing the portion 106 to be made with a reduced thickness compared to the examples described previously, and this for the same light deflection area.

[0076] This variant can also be applied to the second embodiment described above.

[0077] In the various embodiments described above, the oblique portions 114 are formed as parallel strips spaced apart by the flat portions 116. Alternatively, the oblique portions 114 may be staggered and spaced apart by the flat portions 116, as shown, for example, in [Fig. 5]. In this alternative, although only one light source is shown in [Fig. 5], it is possible for the device 100 to include the second light source 124 and for the portion 106 to be symmetrical with respect to a plane perpendicular to the first main face 108. This alternative can be applied to the first or second embodiment.

[0078] According to another embodiment, the oblique portions 114 can form concentric circles or concentric rectangles spaced apart by the flat portions 116, as shown, for example, in [Fig. 6] (in this figure, the example shown corresponds to concentric circles). In this embodiment, although two light sources 104, 124 are shown, it is possible for the device 100 to have a different number of light sources, for example, four light sources, each illuminating one of the four lateral faces of the portion 106. This embodiment can be applied to the first or second embodiment.

[0079] In all the embodiments and variants described above, it is possible for the flat parts 116 and / or the main face not comprising the oblique parts 114 to be covered with an anti-reflective material 126, for example ZnS or SiN. Such a configuration based on the first embodiment is shown, for example, in [Fig. 7]. The addition of this anti-reflective material 126 allows reduce the phenomena of parasitic reflections related to optical index jumps, and thus improves the efficiency of the device 100.

[0080] In all the embodiments and variants described above, the oblique parts 114 can be curved.

[0081] In all the embodiments and variants described above, the portion of material 106 can be produced by laser engraving or micromachining. This technique allows for deep, custom engraving of patterns with a lateral size of up to a few microns, on a very wide variety of materials (metals, glass, silicon, sapphire, etc.), and on surfaces of several mm².

[0082] It may be envisaged to produce a fine reference mold (for example metallic) by laser micromachining, which is then used to produce the negative of the patterns with a more economical material and / or with a lower optical index such as a resin (assumed to be transparent in the spectral band of interest), the element obtained corresponding to element 106.

[0083] Alternatively, it is possible that the oblique parts 114 and the flat parts 116 are obtained by successive stages of lithography and engraving, or of lithography by direct laser writing.

[0084] In the second embodiment, the reflective material formed on the angled parts 114 can be obtained by metallic deposition, for example through a masking grid so that only the angled sides are covered by the deposited material. For example, the portion of material 106 may be positioned in a deposition device such that it receives a metal deposit sent laterally, so that the deposit then covers almost exclusively the angled parts 114 and not the flat parts 116.

Claims

Claims

1. An imaging device (100) configured to image a sample (102), comprising at least: - a first light source (104) configured to emit light; - a light deflection device configured to deflect the light intended to be emitted by the first light source (104) towards the sample (102), comprising a portion of material (106) provided with a first main face (108) intended to be arranged facing the sample (102), a second main face (110) opposite the first main face (108), and a first lateral face (112) towards which the light is intended to be emitted by the first light source (104); one of the first and second main faces (108, 110) being provided with oblique portions (114) with respect to the other of the first and second main faces (108, 110) and each configured to deflect a portion of the light received towards the sample (102), and with flat portions (116) parallel to the other of the first and second main faces (108, 110) and configured to allow the light backscattered by the sample (102) to pass through, - an imager (118) comprising a plurality of pixels (120) and having a detection face (122) arranged opposite the second main face (110) of the light deflection device and intended to receive the light backscattered by the sample (102); characterized in that each pixel (120) of the imager (118) is arranged opposite one of the flat parts (116) of said one of the first and second main faces (108, 110).

2. The imaging device (100) of claim 1, wherein: - said one of the first and second main faces (108, 110) corresponds to the second main face (110); - the light intended to be emitted by the first light source (104) is intended to enter the portion of material (106) of the light deflection device via the first lateral face (112); - the portion of material (106) of the light deflection device comprises a material whose refractive index ni is greater than the refractive index n2 of the medium in which said portion of material (106) is located.

3. Imaging device (100) according to claim 2, further comprising a collimator (111) interposed between the first light source (104) and the first lateral face (112) of the light deflection device.

4. Imaging device (100) according to claim 1, wherein: - said one of the first and second main faces (108, 110) corresponds to the first main face (108); - the portion of material (106) of the light deflection device comprises a material whose refractive index ni is greater than the refractive index n2 of the medium in which said portion of material (106) is located; - the oblique parts (114) of said one of the first and second main faces (108) are covered with a material reflective with respect to the light intended to be emitted by the first light source (104).

5. An imaging device (100) according to one of the preceding claims, wherein the oblique portions (114) of said one of the first and second main faces (108, 110) form parallel strips spaced from each other by the planar portions (116).

6. An imaging device (100) according to one of claims 1 to 4, wherein the oblique portions (114) are arranged in a staggered manner and spaced apart from each other by the planar portions (116).

7. An imaging device (100) according to one of claims 1 to 4, wherein the oblique portions (114) form concentric circles or concentric rectangles spaced from each other by the planar portions (116).

8. An imaging device (100) according to one of the preceding claims, further comprising a second light source (124) configured to emit light similar to that emitted by the first light source (104), wherein the portion of material (106) is provided with a second lateral face (126) opposite the first lateral face (112) and towards which the second light source (124) is intended to emit its light, and wherein the portion of material (106) is symmetrical with respect to a plane perpendicular to the other of the first and second main faces (108, 110).

9. Imaging device (100) according to one of the preceding claims, wherein the portion of material (106) comprises at least one of the following materials: germanium, undoped silicon, ZnSe, ZnS, CaF2,

10.

11.

12.

13. chalcogenide glass. Imaging device (100) according to one of the preceding claims, wherein the planar portions (116) of said one of the first and second main faces (108, 110) and / or the other of the first and second main faces (108, 110) are covered with an anti-reflective material (126). Imaging device (100) according to one of the preceding claims, wherein the oblique portions (114) are curved. Method for producing an imaging device (100) configured to image a sample (102), comprising at least: - providing a first light source (104) configured to emit light; - production of a light deflection device configured to deflect the light intended to be emitted by the first light source (104) towards the sample (102), comprising a portion of material (106) provided with a first main face (108) intended to be arranged opposite the sample (102), a second main face (110) opposite the first main face (108), and a first lateral face (112) towards which the light is intended to be emitted by the first light source (104); the production of the light deflection device including the production, at one of the first and second main faces (108, 110), of oblique portions (114) with respect to the other of the first and second main faces (108, 110) and each configured to deflect a portion of the light received towards the sample (102), and of flat portions (116) parallel to the other of the first and second main faces (108, 110) and configured to allow the light backscattered by the sample (102) to pass; - providing an imager (118) comprising a plurality of pixels (120) and having a detection face (122) arranged opposite the second main face (110) and intended to receive the light backscattered by the sample (102); characterized in that each pixel (120) of the imager (118) is arranged opposite one of the flat parts (116) of said one of the first and second main faces (108, 110). The method of claim 12, wherein the production of the oblique portions (114) and the flat portions (116) of the portion of material (106) of the light deflection device comprises implementing of laser engraving of the portion of material (106).

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