Photodetector device with optical guidance element

Abstract

Photodetector device with optical guiding element This description relates to a photodetector device (100) comprising: - an optical guiding element (104); - an electronic component (102) for converting light into an electrical signal, configured to detect light on the side of a first face (116) of the electronic component disposed opposite the optical guiding element and on the side of a second face (118) of the electronic component opposite the first face; - a reflective layer (120) disposed on the side of the second face of the electronic component; - an optical component (124) disposed between the reflective layer and the optical guiding element and at least partially transparent to the light intended to be detected by the electronic component; and in which the reflective layer forms a reflective surface (122) conforming to a non-planar surface of the optical component on which the reflective layer is disposed.Figure for the abridged version: Fig. 1.

Description

Title of the invention: Photodetector device with optical guidance element. Technical field

[0001] This description relates generally to photodetector devices, or photoreceptors, with optical guiding elements, or light guiding elements. Prior art

[0002] Light is a measurement method increasingly used in the healthcare field to determine, diagnose, and monitor physiological parameters of interest, such as heart rate, blood oxygenation levels, or blood glucose levels. To achieve this, light is injected through the epidermis and then collected after interacting with the tissues of interest through absorption and / or diffusion processes, allowing the targeted physiological parameters to be measured. However, the amount of light collected is very low due to the high rate of absorption and diffusion of light in the tissues.

[0003] It is known to use organic photodiodes, or OPDs (Organic Photodiodes), to receive and capture light and transform it into a measurable quantity corresponding to an electrical signal. OPDs have now reached performance levels that allow their use in various products and fields of application. The use of organic materials for photodetection offers several advantages over semiconductor photodiodes: access to all the intrinsic properties of these materials, to the geometry of the OPD and the absorption wavelengths, and the possibility of deposition on flexible substrates, allowing, for example, optimal fitting of the OPD to a part of the body for medical applications.

[0004] Despite these various advantages, OPDs are limited in their use due to their high dark current (several orders of magnitude higher than that of a silicon-based photodiode, for example), which degrades the measured signal-to-noise ratio (SNR). However, a high SNR is necessary to detect weak signals such as those obtained in physiological parameter monitoring applications and to obtain a reliable and robust measurement.

[0005] In order to improve the SNR of an OPD, the document “Vacuum-Processed Small Molecule Organic Photodetectors with Low Dark Current Density and Strong Response to Near-Infrared Wavelength” by CC. Lee et al., Adv. Optical Mater. 2020, Volume 8, Issue 17, p. 2000519, proposes the reuse of low-noise organic materials. However, the use of such materials is restrictive.

[0006] The document “Organic narrowband near-infrared photodetectors based on intermolecular charge-transfer absorption” by Siegmund, B. et al., Nat. Commun 8, 15421 (2017) proposes improving the signal-to-noise ratio (SNR) of an optical photodetector (OPD) by creating an optical cavity within it. This cavity traps the light to be detected within the OPD stack and causes multiple round trips of the light through the organic photosensitive material of the OPD, thereby increasing light absorption by the photosensitive material and ultimately increasing the output electrical signal level while maintaining the same noise level. This solution is effective for a given wavelength defined by the thickness of the optical cavity. However, when several wavelengths are intended to be detected by the OPD, or when the wavelength to be detected is likely to change, the resonant cavity no longer provides any advantage.

[0007] Similar problems are also found in other fields such as optical communications, for example when it comes to optimizing the coupling between an optical guiding element, for example a waveguide, and an electronic component for converting light into an electrical signal. Summary of the invention

[0008] There is a need to propose a solution that addresses at least some of the disadvantages outlined above.

[0009] One embodiment overcomes all or part of these drawbacks and proposes a photodetector device comprising at least:

[0010] - an optical guiding element;

[0011] - an electronic component for converting light into an electrical signal, configured to detect light at least on the side of a first face of the electronic component arranged opposite the optical guiding element and on the side of a second face of the electronic component opposite the first face;

[0012] - a reflective layer disposed on the side of the second face of the component electronics;

[0013] - an optical component disposed between the reflective layer and the guiding element optical and at least partially transparent to the light intended to be detected by the electronic component;

[0014] and wherein the reflective layer forms at least one reflective surface conforming to a non-planar surface of the optical component on which the reflective layer is disposed.

[0015] According to a particular embodiment, the electronic component comprises at least one photodiode.

[0016] According to a particular embodiment, the electronic component comprises at least one layer of organic material.

[0017] According to a particular embodiment, the optical component comprises at least one concave part.

[0018] According to a particular embodiment, the reflective surface forms at least one spherical or conical or hyperbolic or parabolic mirror.

[0019] According to a particular embodiment, the reflective layer comprises at least one metallic layer and / or at least one Bragg mirror.

[0020] According to a particular embodiment, the photodetector device further comprises at least one substrate at least partially transparent to the light intended to be detected by the electronic component and disposed between the optical guiding element and the electronic component.

[0021] According to a particular embodiment, the optical guidance element comprises at least one microneedle at least partially transparent to light intended to be detected by the electronic component, or at least one waveguide.

[0022] According to a particular embodiment, the optical guidance element comprises a base at least partially transparent to light intended to be detected by the electronic component and several microneedles at least partially transparent to light intended to be detected by the electronic component and each comprising a first end integral with the base, the base being disposed between the electronic component and the microneedles.

[0023] According to a particular embodiment, the photodetector device comprises several distinct electronic components.

[0024] According to a particular embodiment, each of the electronic components is arranged directly above one of the microneedles, or each of the electronic components is arranged directly above a group of microneedles, or in which a group of electronic components is arranged directly above each of the microneedles, or electronic components are arranged directly above spaces between microneedles.

[0025] A physiological parameter measurement device is also proposed, comprising at least one photodetector device as previously described.

[0026] A photovoltaic device comprising at least one photodetector device as previously described is also proposed.

[0027] A method for implementing a photodetector device is also proposed, comprising at least:

[0028] - realization of at least one optical guidance element;

[0029] - realization of at least one electronic component for converting light into an electrical signal, configured to detect light at least on the side of a first face arranged opposite the optical guiding element and on the side of a second face opposite the first face;

[0030] - fabrication of at least one reflective layer disposed on the side of the second face of the electronic component;

[0031] - realization of at least one optical component disposed between the reflective layer and the optical guiding element is at least partially transparent to the light intended to be detected by the electronic component;

[0032] and in which the reflective layer is made such that it forms at least one reflective surface conforming to a non-planar surface of the optical component on which the reflective layer is disposed.

[0033] According to a particular embodiment:

[0034] - the electronic component and the reflective layer are made on the element of optical guidance, or

[0035] - the electronic component and the reflective layer are made on a substrate with less partially transparent to the light intended to be detected by the electronic component, the substrate is then attached to the optical guidance element. Brief description of the drawings

[0036] These features and advantages, as well as others, will be described in detail in the following description of particular embodiments and examples, given by way of non-limiting example, in relation to the accompanying figures, among which:

[0037] - Figure 1 schematically represents an example of a photodetector device according to a particular embodiment;

[0038] - Fig. 2 represents curves showing the light power received by a photoconversion electronic component configured to detect light on two opposite faces, depending on the radius of the photoconversion electronic component, in a photodetector device according to a particular embodiment;

[0039] - [Fig.3], [Fig.4], [Fig.5], [Fig.6], [Fig.7], [Fig.8], [Fig.9] and [Fig. 10] represent steps in an example of a process for making a photodetector device according to a particular embodiment. Description of the implementation methods

[0040] The same elements have been designated by the same reference numerals in the different figures. In particular, the structural and / or functional elements common to the different embodiments may have the same reference numerals and may have identical structural, dimensional and material properties.

[0041] In the figures, in order to facilitate their reading, the different elements and the different layers of materials are not represented at the same scale relative to each other.

[0042] For the sake of clarity, only the steps and elements useful for understanding the described embodiments have been represented and are detailed.

[0043] Unless otherwise specified, when referring to two elements connected together, this means directly connected without intermediate elements other than conductors, and when referring to two elements linked or coupled together, this means that these two elements can be connected or linked through one or more other elements.

[0044] In the following description, when reference is made to absolute positional qualifiers, such as "front," "back," "top," "bottom," "left," "right," etc., or relative positional qualifiers, such as "above," "below," "superior," "inferior," "lateral," etc., or to orientational qualifiers, such as "horizontal," "vertical," etc., unless otherwise specified, reference is made to the orientation of the figures. However, these terms do not imply the actual position and orientation of the device during its use.

[0045] In the figures, in order to facilitate their reading, the different elements and the different layers are not represented at the same scale relative to each other.

[0046] Unless otherwise specified, the expressions "approximately", "roughly", "about", and "in the order of" mean to the nearest 10%, preferably to the nearest 5%. Furthermore, unless otherwise indicated, the ranges of values ​​given include the bounds of those ranges.

[0047] Throughout the document, the expression "at least partially transparent" is used to characterize the fact that an element can be traversed by at least some part (for example at least 40% or at least 50% or at least 70% or at least 90%) of the light received as input to that element.

[0048] An example of a photodetector device 100 according to a particular embodiment is described below in relation to [Fig.1].

[0049] In this embodiment, the device 100 corresponds to a physiological parameter measurement device having a part formed of microneedles intended to be inserted into tissues, through the outer surface of the skin.

[0050] The device 100 comprises at least one electronic component 102 for converting light into an electrical signal, that is, a photoconversion or photodetection electronic component. In the described embodiment, the device 100 comprises several distinct electronic components 102 spaced apart from one another. However, the device 100 may also comprise a single electronic component 102.

[0051] In the described embodiment, each of the electronic components 102 comprises at least one photodiode. More specifically, in the described example, each electronic component 102 corresponds to a photodiode. Furthermore, in this example, the electronic components 102 are organic in nature, that is, they comprise one or more organic materials, and correspond to OPDs.

[0052] In the example described, each of the electronic components 102 comprises first and second electrodes, one corresponding to the anode and the other to the cathode of the photodiode formed by the electronic component 102, which is based on at least one electrically conductive material. The electrodes are at least partially transparent (and preferably totally or almost totally transparent) to at least one light intended to be detected by the electronic component 102. In addition, each of the electronic components 102 comprises at least one photodetection layer, or photosensitive layer, comprising at least one organic semiconductor material and disposed between the first and second electrodes. The thickness (dimension parallel to the Z-axis in [Fig. 1]) of each electronic component 102 is, for example, between 50 nm and 500 nm.As an example, the electrodes of each of the electronic components 102 may comprise at least one of the following materials: Al, Ag, ITO, SnO2, etc. The photodetection layer of each electronic component 102 may comprise, depending on the wavelength(s) intended to be detected, at least one of the following types of materials: CuPc (copper phthalocyanine), ZnPc (zinc phthalocyanine), C6O, ClAlPc (chloroaluminum phthalocyanine), PCBM, PbPc (lead phthalocyanine), etc.

[0053] The device 100 further comprises at least one optical guidance element 104. In the described embodiment, the optical guidance element 104 comprises a base 106 that is at least partially transparent (and preferably totally or almost totally transparent) to the light intended to be detected by the electronic components 102, as well as several microneedles 108 that are also at least partially transparent (and preferably totally or almost totally transparent) to the light intended to be detected by the electronic components 102. The microneedles 108 are intended to be inserted into tissues 110 corresponding to superficial layers of the skin. Each of the microneedles 108 has a first end 112 attached to the base 106 and a second pointed end 114.More specifically, in the example described, each microneedle 108 has a cylindrical portion extending from the first end 112 and continuing with a conical portion to the second end 114. Alternatively, different shapes of microneedles 108 than that described above are possible. For example, the cross-section of the microneedles 108 may... be of a shape other than a disc. In addition, shapes other than a point are conceivable, for example to orient the optical guidance element 104 or to couple it with a local diffuser arranged at the end of the microneedles 108.

[0054] In the described embodiment, the microneedles 108 are configured to guide the light scattered from the tissues 110 to the surface of the base 106 on which the electronic components 102 are arranged. The conical shape of the tips of the microneedles 108 allows the microneedles 108 to penetrate the skin effectively and also ensures good collection of the guided light in the cylindrical part of the microneedles 108. In the described example, the light guidance within the microneedles 108 is achieved through the difference in refractive index between the material of the microneedles 108 and the tissues 110. By way of example, the height of each of the microneedles 108 (dimension parallel to the Z-axis in [Fig. 1]) can be between 100 µm and 3 mm.The cross-section of the cylindrical portion of each of the microneedles 108 has, for example, in a plane perpendicular to their height (plane parallel to the (X,Y) plane in the example of [Fig. 1]), a diameter between 50 pm and 900 pm. The pitch of the microneedles 108, that is, the distance separating the axes of revolution of two adjacent microneedles 108, can be between approximately 100 pm and several millimeters, or be greater than or equal to 500 pm. According to one embodiment, the microneedles 108 can be made of a biocompatible material such as a polymer, for example polymethyl methacrylate or PMMA, or PLGA (poly(lactic-co-glycolic acid)).

[0055] When the device 100 is intended for applications other than the measurement of physiological parameters by photodetection of light propagating in the skin, the optical guidance element 104 may include the base 106 to which are optically coupled one or more elements at least partially transparent (and preferably totally or almost totally transparent) to the light intended to be detected by the electronic components 102, this or these elements being different from the microneedles 108.

[0056] Thus, the optical guidance element 104 may include, for example, at least one microneedle, or at least one waveguide (example of an application other than the measurement of physiological parameters) or other types of element depending on the application envisaged (for example, the field of photovoltaics), and the optical guidance element 104 may or may not include the base 106.

[0057] Each of the electronic components 102 is configured to detect light at least on the side of a first face 116 arranged opposite the optical guiding element 104 and also on the side of a second face 118 opposite the first face 116. This light detection on the side of each of the faces 116, 118 is due, in this embodiment, to the fact that the electronic components 102 correspond to OPDs whose organic photodetection layer(s) detect light on the side of each of the electrodes (first electrode located on the side of the first face 116 and second electrode located on the side of the second face 118). Alternatively, this light detection from both faces 116, 118 of the electronic components 102 can be obtained by using other types of electronic components 102 configured to detect light from two opposite sides, or faces.

[0058] In the described embodiment, the first face 116 of each of the electronic components 102 is disposed directly against the optical guiding element 104, and more particularly against the base 106 of the optical guiding element 104. Alternatively, it is possible that at least one element at least partially transparent, or preferably totally or almost totally transparent, to the light intended to be detected by the electronic components 102, for example a substrate of glass or of any other transparent or semi-transparent material, is interposed between the electronic components 102 and the optical guiding element 104, such as conical bases on which the microneedles are disposed, and with a possible base on which the conical bases rest.

[0059] The device 100 further comprises at least one reflective layer 120 disposed on the side of the second faces 118 of the electronic components 102 and forming a reflective surface 122 facing the electronic components 102. This surface 122 is described as reflective because it is configured to reflect at least some, and preferably all or almost all, of the light transmitted from the optical guiding element 104 that has not been absorbed by the first faces 116 of the electronic components 102, in order to increase the total amount of light absorbed by the electronic components 102. The reflective layer 120 comprises, for example, at least one metal such as silver or aluminum. The thickness of the reflective layer 120 is, for example, between 50 nm and 500 nm.

[0060] Alternatively, the reflective layer 120 may include at least one Bragg mirror configured to reflect the wavelength(s) of interest intended to be detected by the electronic components 102.

[0061] In all cases, the properties of the reflective layer 120 (material(s) used, thickness, shape, etc.) can be such that the reflective surface 122 reflects as much light as possible in order to have the lowest possible light loss at the level of this reflective layer 120.

[0062] The device 100 further comprises at least one optical component 124 disposed between the reflective layer 120 and the optical guiding element 104, and more particularly between each of the electronic components 102 and the reflective layer 120. In the example of [Fig. 1], the device 100 comprises several Optical components 124 are each arranged directly above one of the microneedles 108 and also between one of the electronic components 102 and the reflective layer 120. The pitch (distance between the centers of two adjacent optical components 124) with which the optical components 124 are made can be equal to that of the microneedles 108. The optical components 124 are at least partially transparent, and preferably totally or almost totally transparent, to the light intended to be detected by the electronic components 102. According to one embodiment, the optical components 124 comprise a resin-type polymer (for example, PMMA or PLGA) or an oxide such as SiO2 or SiN or any other suitable material. In addition, the thickness of each of the optical components 124 (i.e. their dimension parallel to the Z axis in the example of [Fig.1]) is for example between 50 pm and 2 mm, or greater than or equal to 100 pm.

[0063] The reflective layer 120 is arranged on the optical components 124 such that the reflective surface 122 conforms to a non-planar surface of the optical components 124 and thus achieves light reflection with a desired directivity and / or focus defined by the shape of the non-planar surface of the optical components 124. Thus, the geometry of the reflective surface 122 opposite each microneedle 108 depends on that of the non-planar surface of each optical component 124. In the described embodiment, each optical component 124 forms a concave surface on which the reflective layer 120 is arranged, this shape corresponding to that of the reflective surface 122. For example, the optical components 124 can be such that the reflective surface 122 forms, opposite each microneedle 108, at least one spherical mirror, or spherical cap, or conical, or hyperbolic, or advantageously parabolic.Other shapes are conceivable: cube corner, ellipse, etc. Alternatively, each optical component 124 can have another non-planar shape adapted so that the reflective surface 122 achieves a desired light reflection towards the electronic components 102. For example, the optical components 124 can be such that, combined with the reflective surface 122, they allow the local increase in the directivity of the light to reflect it at an appropriate angle towards the electronic components 102.

[0064] For example, when the device 100 is used for photovoltaic applications, having a reflective surface 122 forming a parabolic mirror makes it possible to cover a much wider spectral range than when microlenses are used (limited by the reflective properties of the materials used). The advantages are obtained for all wavelengths.

[0065] Thus, the optical components 124 combined with the reflective surface 122 can be configured to focus the light on the side of the second face 118 of each of the electronic components 102.

[0066] In the device 100, in order to limit crosstalk between the electronic components 102, it is possible to reduce the thickness of the base 106 as much as possible, and more generally to reduce the distance between the electronic components 102 and the first ends 112 of the microneedles 108 to prevent light from one of the microneedles 108 from being detected by an electronic component 102 different from the one placed directly above that microneedle.

[0067] As an alternative to the embodiment described above, the optical guiding element 104 can be a waveguide. The device 100 in such a variant can, for example, be used in the field of optical communications to optimize the optical coupling between the electronic components 102 and the waveguide corresponding to the optical guiding element 104.

[0068] Curves shown in [Fig. 2] illustrate the fraction of light power emitted from one of the microneedles 108 and received by one of the electronic components 102 positioned directly above this microneedle 108, as a function of the radius (in microns) of the electronic component 102 (considering here that the electronic component 102 has a disk-shaped cross-section in a plane perpendicular to the axis of revolution of the microneedle 108). In [Fig. 2], the received power fraction is defined as the ratio of the detected light power to the total light power initially emitted from the microneedle 108.Curve 200 represents the fraction of light power received through the second face 118 of the electronic component 102, curve 202 represents the fraction of light power received through the first face 116 of the electronic component 102, and curve 204 represents the sum of the fractions of light power received through the two faces 116, 118 of the electronic component 102. These values ​​are obtained for: .

[0069] - a microneedle 108 with a diameter of 400 pm from which a luminous flux is produced with a half-angle of opening of 25°;

[0070] - a reflective surface 122 of parabolic conical shape with a radius of 1 mm, height (dimension parallel to the axis of revolution of the microneedle 108) equal to 0.312 mm and focal length equal to 0.2 mm, the electronic component 102 being centered on the focal point of the reflective surface 122.

[0071] In this case, when the radius of the electronic component 102 is equal to 500 pm, 100% of the light is detected by the first face 116 of the electronic component 102. By reducing the diameter of the electronic component 102, 100% of the light is still detected by the electronic component 102 when the radius of the electronic component 102 is between 500 pm and 220 pm, thanks to reflection of the light on the reflective surface 122 and its deviation towards the second face 118 of the electronic component 102. These curves show that it is possible to greatly reduce the dimensions of the electronic component 102, and therefore, in the case of an electronic component 102 corresponding to an OPD, to greatly reduce its dark current and thus greatly increase its SNR, while maintaining a high light detection rate.

[0072] Alternatively, one or more electronic components 102 may be arranged not opposite the microneedle(s) 108, but beside or between them. Thus, it is possible, for example, to separate the information from the surface of the tissues 110 from that from the interior of the tissues 110, and thereby measure the potential information in the inter-microneedle space. In such an alternative, the electronic component(s) 102 may be arranged on the base 106. Furthermore, in such an alternative, the electronic component(s) 102 may correspond to one or more structured OPDs.

[0073] An example of a method for making device 100 is described below in relation to figures 3 to 10.

[0074] In this example, the electronic components 102, the reflective layer 120, and the optical components 124 are made on a substrate 126 that is at least partially transparent, and preferably totally or almost totally transparent, to the light intended to be detected by the electronic components 102. The thickness of the substrate 126 is, for example, a few hundred microns. For example, the substrate 126 may be made of glass.

[0075] Alternatively, it is possible that the electronic components 102, the reflective layer 120 and the optical components 124 are made directly on the optical guiding element 104, as is the case in the example of [Fig.1].

[0076] In the described embodiment, the electronic components 102 correspond to OPDs. Thus, in this example, a first transparent or semi-transparent electrode 128, that is, capable of allowing at least some of the light intended to be detected by the electronic components 102 to pass through, is made on the substrate 126. The first electrode 128 corresponds, for example, to the anode of the electronic components 102. At least one contact pad 130, to which a second electrode of the electronic components 102 is intended to be electrically coupled, is also made on the substrate 126, next to the first electrode 128 (see [Fig. 3]).

[0077] In the example described, the first electrode 128 is common to the various electronic components 102. Alternatively, it is possible that each electronic component 102 has a first electrode 128 that is distinct from and electrically isolated from the first electrodes 128 of the other electronic components 102, or that several first electrodes 128, distinct and electrically isolated from each other, are made on the substrate 126, each of them being coupled to several electronic components 102.

[0078] Insulating portions 132, comprising for example resin, are then formed, for example by deposition, around the periphery of the first electrode 128 and between locations of the future active photodetection regions of the electronic components 102, i.e., between the locations where the portions of the layer(s) intended to ensure light detection will be arranged (see [Fig. 4]). The insulating portions 132 arranged on the edges of the first electrode 128 are intended to electrically isolate the first electrode 128 from the electrical connection that will be made between the second electrode of the electronic components 102 and the contact pad 130.

[0079] One or more light-sensing layers 134, comprising here at least one organic material, are then deposited on the first electrode 128, between the insulating portions 132 (see [Fig. 5]). This deposition is, for example, carried out using a stencil to locate the deposit of this or these light-sensing layers 134 at the desired locations between the insulating portions 132.

[0080] A second transparent or semi-transparent electrode 136 is then made on the light detection layer(s) 134 and the insulating portions 132. This second electrode 136 corresponds, for example, to the cathode of the electronic components 102. A part of this second electrode 136 is deposited on at least one of the insulating portions 132 arranged on one of the edges of the first electrode 128 and on a part of the substrate 126 so as to be in contact with the contact pad 130 (see [Fig.6]).

[0081] In the example described, the second electrode 136 is common to the different electronic components 102. Alternatively, it is possible that each electronic component 102 has a second electrode 136 that is separate and electrically isolated from the second electrodes 136 of the other electronic components 102, or that several second electrodes 136 that are separate and electrically isolated from each other are made, each of them being coupled to several electronic components 102.

[0082] At this stage of the process, the production of the electronic components 102 is complete.

[0083] Although not visible, at least one transparent or semi-transparent encapsulation layer can then be deposited on the electronic components 102.

[0084] The optical components 124 are then fabricated on the electronic components 102. In the described embodiment, pads 138 of the material(s) intended to form the optical components 124, for example, pads of transparent or semi-transparent resin, are fabricated, for example, by deposition above the second electrode 136 (see [Fig.7]). In the presence of an encapsulation layer covering the electronic components 102, the pads 138 are made on this encapsulation layer.

[0085] A finishing step can then be implemented to give the pads 138 the desired shape and thus form the optical components 124 (see [Fig.8]).

[0086] The reflective layer 120 is then produced, for example by deposition, on the optical components 124 and on the parts of the second electrode 136 not covered by the optical components 124 (see [Fig.9]).

[0087] The device 100 is completed by transferring the structure made onto the guide element 104 comprising, in the described embodiment example, the base 106 and the microneedles 108. This transfer corresponds, in the described example, to a securing of the substrate 126 against the base 106 (see [Fig. 10]).

[0088] In one embodiment, the electronic components 102 can be configured to detect light of different wavelengths. In this case, the light-detecting layer(s) 134 deposited are, for example, different depending on the wavelength(s) intended to be detected.

[0089] In the embodiments described above, the device 100 comprises several electronic components 102, each arranged directly above one of the microneedles 108. Alternatively, the device 100 may comprise a single electronic component 102, corresponding, for example, to a single photodiode, arranged directly above all the microneedles 108. According to another embodiment, the device 100 may comprise several electronic components 102 such that each of them is arranged directly above a group of microneedles 108. According to yet another embodiment, the device 100 may comprise several electronic components 102 such that a group of electronic components 102 is arranged directly above each of the microneedles 108.

[0090] In the embodiment described above, the device 100 corresponds to a device used in the healthcare field to monitor or measure physiological and / or therapeutic parameters. In the device 100, light is a measurement modality used to determine and monitor physiological parameters of interest such as heart rate, blood oxygenation level, blood glucose, SpO2, or SaO2. The light guided in the optical guidance element 104 and detected by the electronic components 102 corresponds to light propagating in the tissues 110 and originating, for example, from a light source external to the tissues 110. The light guided in the optical guidance element 104 has, prior to entering the optical guidance element 104, interacted with the tissues of interest, which carry the information allowing the targeted physiological parameters to be determined.

[0091] Whatever the intended application, the device 100 makes it possible to maximize the collection of photons on the electronic component(s) 102 while keeping, when the electronic components 102 correspond to photodiodes, a reduced detection area allowing to minimize the dark current and thus increase the SNR of the photodiodes in order to make the measurement more reliable and more robust, and this notwithstanding the low strength of the optical signal captured due to the high absorption rate in the skin and the scattering of light in the tissues 110.

[0092] By way of example, compared to a photodetector device which would not be equipped with the reflective surface 122 allowing to reflect the light towards the second face 118 of the electronic components 102, it is possible, with the device 100, to reduce the active photodetection surface of the electronic components 102 for example by a factor of 5.2, which reduces the dark current by the same amount, without reducing the fraction of light power detected by the electronic components 102.

[0093] These advantages are also obtained regardless of the wavelength of the detected light, and also when the light is polychromatic. Furthermore, these advantages are obtained without any particular constraints on the organic materials that can be used for the fabrication of the electronic components 102, and the device 100 is compatible with materials optimized for the desired photodetection.

[0094] The device 100 optimizes the detection of light guided by the optical guiding element 104 by means of the judicious use of the non-planar reflective surface 122 and which, combined with one or more electronic photodetector components 102 detecting light both on the side of the optical guiding element 104 and on the side of the reflective surface 122, makes it possible to increase the amount of light sent towards the electronic component(s) 102 since the light reaching the reflective surface 122 is recovered and reflected towards the electronic component(s) 102 thanks to the light reflection and focusing properties of the reflective surface 122.

[0095] In this example of device 100, the light from the tissues 110 is guided by the microneedles 108. Part of this light can be absorbed by the first face 116 of the electronic components 102 while that which is not is reflected by the reflective surface 122 and sent back to the second face 118 of the components 102 to be detected there.

[0096] Having electronic components 102 corresponding to photodiodes allows us to benefit from their integrability properties. For example, OPDs have the advantage of being robust to the steps implemented for the fabrication of optical components 124.

[0097] The device 100 can be used for other application areas than those previously described, for example within "smart pixels", or intelligent pixels, in screens to optimize the SNR of these pixels, or in any field requiring the realization of a photodiode or a photodetector, especially when the signal received by the photodiode is weak, or even in the photovoltaic field.

[0098] Various embodiments and variants have been described. A person skilled in the art will understand that certain features of these various embodiments and variants could be combined, and other variants will become apparent to a person skilled in the art.

[0099] Finally, the practical implementation of the described embodiments and variants is within the reach of a person skilled in the art, based on the functional specifications given above. For example, the precise nature of the deposition and engraving steps implemented can be chosen according to, in particular, the material(s) to be deposited or engraved, as well as the thicknesses of the materials to be deposited or engraved.

Claims

Demands

1. Photodetector device (100) comprising at least: - an optical guiding element (104); - an electronic component (102) for converting light into an electrical signal, configured to detect light at least on the side of a first face (116) of the electronic component (102) disposed opposite the optical guiding element (104) and on the side of a second face (118) of the electronic component (102) opposite the first face (116); - a reflective layer (120) disposed on the side of the second face (118) of the electronic component (102); - an optical component (124) disposed between the reflective layer (120) and the optical guiding element (104) and at least partially transparent to the light intended to be detected by the electronic component (102);and in which the reflective layer (120) forms at least one reflective surface (122) conforming to a non-planar surface of the optical component (124) on which the reflective layer (120) is disposed.;

2. Photodetector device (100) according to claim 1, wherein the electronic component (102) comprises at least one photodiode.

3. Photodetector device (100) according to any one of the preceding claims, wherein the electronic component (102) comprises at least one layer of organic material (134).

4. Photodetector device (100) according to any one of the preceding claims, wherein the optical component (124) comprises at least one concave portion.

5. Photodetector device (100) according to any one of the preceding claims, wherein the reflective surface (122) forms at least one spherical or conical or hyperbolic or parabolic mirror.

6. Photodetector device (100) according to any one of the preceding claims, wherein the reflective layer (120) comprises at least one metallic layer and / or at least one Bragg mirror.

7. Photodetector device (100) according to any one of the preceding claims, further comprising at least one substrate (126) at least partially transparent to the light intended to be detected by the electronic component (102) and disposed between the optical guidance element (104) and the electronic component (102).

8. Photodetector device (100) according to any one of the preceding claims, wherein the optical guidance element (104) comprises at least one microneedle (108) at least partially transparent to light intended to be detected by the electronic component (102), or at least one waveguide.

9. Photodetector device (100) according to claim 8, wherein the optical guidance element (104) comprises a base (106) at least partially transparent to light intended to be detected by the electronic component (102) and several microneedles (108) at least partially transparent to light intended to be detected by the electronic component (102) and each comprising a first end (112) integral with the base (106), the base (106) being disposed between the electronic component (102) and the microneedles (108).

10. Photodetector device (100) according to any one of the preceding claims, comprising several separate electronic components (102).

11. Photodetector device (100) according to claims 9 and 10, wherein each of the electronic components (102) is disposed above one of the microneedles (108), or wherein each of the electronic components (102) is disposed above a group of microneedles (108), or wherein a group of electronic components (102) is disposed above each of the microneedles (108), or wherein electronic components (102) are disposed above spaces between microneedles (108).

12. Physiological parameter measurement device comprising at least one photodetector device (100) according to any one of the preceding claims.

13. Photovoltaic device comprising at least one photodetector device (100) according to any one of claims 1 to 11.

14. A method for making a photodetector device (100), comprising at least: - making at least one optical guiding element (104); - making at least one electronic component (102) for converting light into an electrical signal, configured to detect light at least on the side of a first face (116) disposed opposite the optical guiding element (104) and on the side of a second face (118) opposite the first face (116); - making at least one reflective layer (120) disposed on the side of the second face (118) of the electronic component (102); - making at least one optical component (124) disposed between the reflective layer (120) and the optical guiding element (124) and at least partially transparent to the light intended to be detected by the electronic component (102);and in which the reflective layer (120) is made such that it forms at least one reflective surface (122) conforming to a non-planar surface of the optical component (124) on which the reflective layer (120) is disposed.;

15. A method of embodiment according to claim 14, wherein: - the electronic component (102) and the reflective layer (120) are made on the optical guidance element (104), or - the electronic component (102) and the reflective layer (120) are made on a substrate (126) at least partially transparent to the light intended to be detected by the electronic component (102), the substrate (126) being subsequently attached to the optical guidance element (104).

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