Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
  • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
  • H01L27/144—Devices controlled by radiation
  • H01L27/146—Imager structures
  • H01L27/14601—Structural or functional details thereof
  • H01L27/14625—Optical elements or arrangements associated with the device
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
  • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
  • H01L27/144—Devices controlled by radiation
  • H01L27/146—Imager structures
  • H01L27/14643—Photodiode arrays; MOS imagers
  • H01L27/14645—Colour imagers
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/20—Filters
  • G02B5/208—Filters for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
  • G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
  • G06V40/10—Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
  • G06V40/12—Fingerprints or palmprints
  • G06V40/13—Sensors therefor
  • G06V40/1318—Sensors therefor using electro-optical elements or layers, e.g. electroluminescent sensing
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
  • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
  • H01L27/144—Devices controlled by radiation
  • H01L27/146—Imager structures
  • H01L27/14601—Structural or functional details thereof
  • H01L27/14625—Optical elements or arrangements associated with the device
  • H01L27/14627—Microlenses
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
  • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
  • H01L27/144—Devices controlled by radiation
  • H01L27/146—Imager structures
  • H01L27/14683—Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof
  • H01L27/14685—Process for coatings or optical elements

Definitions

• Optical filter adapted to correct the electronic noise of a sensor
• the present description relates to an image acquisition system.
• An image acquisition system generally comprises an image sensor and an optical system interposed between the sensitive part of the image sensor and the object to be imaged and which makes it possible to form a clear image of the object to be imaged on the sensitive part of the image sensor.
• the optical system can be an optical filter and more particularly an angular filter.
• An angular filter is a device making it possible to filter incident radiation as a function of the incidence of this radiation and thus block the rays whose incidence is greater than a desired angle, called maximum incidence.
• One embodiment overcomes all or part of the drawbacks of image acquisition systems.
• One embodiment provides an optical filter for an image sensor comprising first, opaque zones, each first zone occupying a surface area equal to the surface area. at least a first lens included in this first zone.
• an optical filter for an image sensor comprising: an array of lenses consisting of first and second lenses juxtaposed and located on the first face of a substrate, the first lenses being included in first opaque zones and the second lenses being included in second zones, each first zone occupying an area equal to the area of at least one first lens included in this first zone; openings, on the second face side of said substrate, at least facing the second lenses; and an opaque layer facing the first lenses on the second face side of said substrate.
• the transmittance of the first zones is less than approximately 0.1%, preferably less than approximately 0.00001%.
• the optical filter comprises second areas, transparent, each second area occupying an area equal to the area of at least one second lens included in this second area.
• the first lenses and the second lenses are coplanar.
• the first zones and the second zones are juxtaposed and organized in rows and columns.
• the first zones are organized in columns which are adjacent and located on one of the edges of the filter. [0014] According to one embodiment, the first zones are organized in columns which are distributed over two edges of the filter.
• the radius of curvature of the first lenses is less than the radius of curvature of the second lenses.
• the radius of curvature of the first lenses is greater than the radius of curvature of the second lenses.
• the optical filter comprises successively: an array of lenses, consisting of the first and second juxtaposed lenses, located on the first face side of a substrate; and a first layer, on the second face side of said substrate, solid facing the first lenses and comprising openings facing the second lenses.
• the optical filter comprises successively: an array of lenses, located on the first face side of a substrate; a first layer comprising a matrix of openings on the second face of said substrate; and a second opaque layer, in each first area.
• the optical filter comprises successively: a lens array, consisting of the first locally deteriorated lenses and the second juxtaposed lenses, located on the first face of a substrate; and a first layer comprising a matrix of openings on the second face of said substrate.
• a method of manufacturing the optical filter comprising among others the following steps: forming, by printing, the lens array on the first face of the substrate; depositing a first layer of a photosensitive resin on the second side of the substrate; and making openings in the first layer by photolithography through the lenses.
• the second layer is formed in the openings in the first zones or on the first or second face of said openings.
• the second layer is formed in the first zones.
• the first lenses are partially damaged by a laser.
• One embodiment provides a system comprising: an optical filter which can be likened to an angular filter; a source of radiation; and an image sensor comprising photodetectors adapted to detect said radiation.
• One embodiment provides for a fingerprint sensor comprising a system as described.
• FIG. 1 illustrates by a sectional view, partial and schematic, an embodiment of an image acquisition system
• FIG. 2 illustrates by a top view, partial and schematic, an embodiment of an image acquisition system
• FIG. 3 illustrates, in a top view, partial and schematic, another embodiment of an image acquisition system
• FIG. 4 illustrates, in a partial and schematic sectional view, yet another embodiment of an image acquisition system
• FIG. 5 illustrates, in a partial and schematic sectional view, a step of a first embodiment of a method for manufacturing an angular filter
• FIG. 6 illustrates, in a partial and schematic sectional view, another step of the first embodiment of the method for manufacturing an angular filter
• FIG. 7 illustrates, in a partial and schematic sectional view, yet another step of the first embodiment of the method for manufacturing an angular filter
• FIG. 8 illustrates, in a partial and schematic sectional view, a step of a second embodiment of a method for manufacturing an angular filter
• Figure 9 illustrates by a sectional view, partial and schematic, another step of the second embodiment of the manufacturing process of an angular filter
• FIG. 10 illustrates, in a partial and schematic sectional view, yet another step of the second embodiment of the method for manufacturing an angular filter
• Figure 11 illustrates by a sectional view, partial and schematic, yet another step of the second mode of implementation of the method for manufacturing an angular filter
• FIG. 12 illustrates, in a partial and schematic sectional view, a step of a third embodiment of a method for manufacturing an angular filter
• FIG. 13 illustrates, in a partial and schematic sectional view, another step of the third embodiment of the method for manufacturing an angular filter
• FIG. 14 illustrates, in a partial and schematic sectional view, yet another step of the third embodiment of the method for manufacturing an angular filter
• FIG. 15 illustrates, in a partial and schematic sectional view, yet another step of the third embodiment of the method for manufacturing an angular filter.
• FIG. 16 illustrates, in a partial and schematic sectional view, a step of a fourth embodiment of a method for manufacturing an angular filter.
• a layer or a film is said to be opaque to radiation when the transmittance of the radiation through the layer or the film is less than 10%.
• a layer or a film is said to be transparent to radiation when the transmittance of the radiation through the layer or the film is greater than 10%.
• all the elements of the optical system which are opaque to radiation have a transmittance which is less than half, preferably less than a fifth, more preferably less than a tenth, of the highest transmittance. weaker transparent optical system elements said radiation.
• the electromagnetic radiation passing through the optical system in operation is called “useful radiation”.
• an optical element formed on one face of a support is called “optical element of micrometric size”.
• a film or a layer is said to be impervious to oxygen when the permeability of the film or of the layer to oxygen at 40 ° C. is less than 1.10 _1 cm 3 / (m 2 .day)
• the oxygen permeability can be measured according to the ASTM D3985 method entitled "Standard Test Method for Oxygen Gas Transmission Rate Through Plastic Film and Sheeting Using a Coulometric Sensor".
• a film or a layer is said to be waterproof when the permeability of the film or of the layer to water at 40 ° C. is less than 1.1CD 1 g / (m 2 .day).
• the water permeability can be measured according to the ASTM F1249 method entitled "Standard Test Method for Water Vapor Transmission Rate Through Plastic Film and Sheeting Using a Modulated Infrared Sensor".
• each micrometric-sized optical element corresponds to a micrometric-sized lens, or microlens, composed of of two dioptres.
• each optical element of micrometric size being able to correspond, for example, to a Fresnel lens of micrometric size, to a lens with a gradient index of micrometric size or to a diffraction grating of micrometric size.
• visible light is called electromagnetic radiation whose wavelength is between 400 nm and 700 nm and infrared radiation is called electromagnetic radiation whose wavelength is between 700 nm and 1 mm.
• infrared radiation one distinguishes in particular near infrared radiation, the wavelength of which is between 700 nm and 1.7 ⁇ m.
• a manufacturing step is assimilated to the structure obtained at the end of this step.
• Figure 1 illustrates by a sectional view, partial and schematic, an embodiment of an image acquisition system.
• the acquisition system 1 comprises from top to bottom: a light source 11 which emits radiation 13; an object 15; an optical filter 17; and an image sensor 19, for example a complementary Metal-Oxide semiconductor CMOS (Complementary Metal Oxide Semiconductor) sensor or a sensor based on thin film transistors (TFT, Thin Film Transistor), which can be coupled to inorganic photodiodes (crystalline silicon for a CMOS sensor or amorphous silicon for a TFT sensor) or organic.
• CMOS Complementary Metal Oxide Semiconductor
• TFT Thin Film Transistor
• the image acquisition system 1 further comprises circuits, not shown, for processing the signals supplied by the image sensor 19, comprising, for example, a microprocessor.
• the light source 11 is illustrated above the object 15. It can however, as a variant, be located between the object 15 and the optical filter 17.
• the radiation 13 is, for example, in the visible range and / or in the infrared range. It may be radiation of a single wavelength or radiation of several wavelengths (or range of wavelengths).
• the photodiodes of the image sensor 19 generally form a pixel network. Each photodiode defines a pixel of the image sensor 19. Within the array, the photodiodes are, for example, aligned in rows and columns.
• Some of the photodiodes of the network are generally used as a reference in order to detect and record only the noise of the sensor 19 and of its electronics. The noise is then deduced from the signals picked up by the other photodiodes of the sensor 19 in order to correct them. For this, the incident radiation at the reference photodiodes is generally cut (absorbed or reflected) by an opaque mask
• the mask is generally positioned next to the optical filter 17, that is to say it covers the sensor 19 outside the optical filter.
• the mask is generally coplanar with the optical filter 17.
• pixel is used to denote a photodiode
• reference pixel to denote a photodiode receiving no usable light radiation
• useful pixel to denote a pixel which provides a useful signal of the captured image
• FIG. 2 illustrates by a top view, partial and schematic, an embodiment of an image acquisition system 1. More particularly, FIG. 2 illustrates an example of distribution of useful pixels 21 and of reference pixels 23 within an image acquisition system 1.
• the pixels 21 and 23 are preferably aligned in rows and columns.
• the pixels 21 and 23 are, for example, organized in about 2500 rows and about 1300 columns for an imager having a resolution of 500 dpi (ie a pixel pitch of 50.8 ⁇ m).
• the resolution of the imager can, for example, vary between 254 dpi (ie a pixel pitch of 100 ⁇ m) and 1000 dpi (ie a pixel pitch of 25 ⁇ m).
• the pixels 21 and 23 are organized in the network so that at least one reference pixel 23 is present per line.
• the reference pixels 23 are all aligned in the same columns. For example, between about 4 columns and about 64 columns include only reference 23 pixels. Preferably, between about 16 columns and about 32 columns include only 23 reference pixels.
• the reference pixel columns 23 are all juxtaposed and located on one of the edges of the system 1 (to the left of the system 1 in the orientation of FIG. 2).
• FIG. 3 illustrates, in a top view, partial and schematic, another embodiment of an image acquisition system.
• the embodiment illustrated in Figure 3 is substantially identical to the embodiment illustrated in Figure 2 with the difference that the reference pixel columns 23 are located on the two edges of the system 1. De Preferably, the same number of reference pixel columns 23 are found in each edge of the system 1.
• the electronic noise is detected by all the photodiodes of the reference pixels 23.
• the electronic noise detected by photodiodes of the reference pixels 23 of the same row is averaged .
• the average noise is then used to correct the useful signals detected by the photodiodes of the useful pixels 21 of the same line.
• FIG. 4 illustrates, in a partial and schematic sectional view, another embodiment of an image acquisition system.
• the image acquisition system 1 illustrated in FIG. 4 comprises: an angular filter 17; and the image sensor 19 comprising photodiodes or photodetectors 191.
• the angular filter 17 comprises from top to bottom in the orientation of Figure 4: a lens array 25; a substrate or support 27; and a first layer 29 of a first resin 31 comprising openings 33, or holes, and walls 35.
• optical filter 17 constituting an angular filter.
• these embodiments can be applied to other types of optical filters such as, for example, a Red Green Blue RGB (Red Green Blue) color filter.
• Red Green Blue RGB Red Green Blue
• the angular filter 17 is adapted to filter the incident radiation as a function of the incidence of the radiation relative to the optical axes 24 of the lenses 25.
• the angular filter 17 is adapted so that each photodetector 191 of the image sensor 19 receives only the rays whose respective incidences with respect to the respective optical axes 24 of the lenses 25 associated with this photodetector 191 are less than a maximum angle of incidence of less than 45 °, preferably less than 30 °, more preferably less than 10 °, even more preferably less than 4 °.
• the angular filter 17 is adapted to block the rays of the incident radiation whose respective incidences with respect to the optical axes 24 of the lenses 25 of the filter 17 are greater than the maximum angle of incidence.
• Each opening 33 is preferably associated with a single lens 25.
• the optical axes 24 of the lenses 25 are preferably centered with the centers of the openings 33 of the first layer 29.
• the diameter of the lenses 25 is, preferably greater than the maximum size of the section (perpendicular to the optical axis of the lenses 25) of the apertures 33.
• each photodetector 191 is shown associated with a single opening 33, the center of each detector 191 being centered with the center of the opening 33 with which it is associated.
• the resolution of the angular filter 17 is at least twice the resolution of the image sensor 19.
• the system comprises at least twice as many lenses 25 (or apertures 33) as photodetectors. 191.
• a photodiode 191 (FIG. 4) is associated with at least two lenses 25 (or apertures 33).
• the term “zone” denotes each part of the filter 17 comprising at least one lens 25 and the underlying layers. For example, an area is associated with a single pixel but a pixel is associated with at least two areas. Each zone has a surface substantially identical to the surface of the lens 25 associated with the zone.
• the first zones correspond to the parts of the optical filter 17 facing the reference pixels 23 (FIGS. 2 and 3) and the second zones correspond to the parts of the optical filter 17 facing the useful pixels. 21 (figures 2 and 3).
• the upper face of a structure or of a layer is considered, in the orientation of FIG. 4, as being the front face and the lower face of the structure or of the layer. , in the orientation of Figure 4, as the rear face.
• Figures 5 to 7 illustrate, schematically and partially, successive steps of an example of a method of manufacturing an angular filter 17 according to a first embodiment.
• FIG. 5 illustrates, in a partial and schematic sectional view, a step of the first embodiment of the method for manufacturing an angular filter 17.
• FIG. 5 represents a starting structure comprising an array of first lenses 253 and of second coplanar lenses 251 and the substrate 27.
• the substrate 27 can be made of a transparent polymer which does not absorb at least the wavelengths considered, here in the visible and infrared range.
• This polymer can in particular be poly (ethylene terephthalate) PET, poly (methyl methacrylate) PMMA, a cyclic olefin polymer (COP), a polyimide (PI) or a polycarbonate (PC).
• the thickness of the substrate 27 may, for example, vary from 1 to 100 ⁇ m, preferably between 20 and 100. mpi.
• the substrate 27 can correspond to a color filter, to a polarizer, to a half-wave plate or to a quarter-wave plate.
• the lenses or microlenses 251 and 253, on and in contact with the substrate 27, can be made of silica, of PMMA, of a positive photosensitive resin, of PET, of poly (ethylene naphthalate) (PEN), of COP, polydimethylsiloxane (PDMS) / silicone, epoxy resin or acrylate resin.
• Microlenses 251 and 253 can be formed by creeping blocks of a photosensitive resin.
• the microlenses 251 and 253 can further be formed by molding on a layer of PET, PEN, COP, PDMS / silicone, epoxy resin or acrylate resin.
• Lenses 251 and 253 can be formed by printing.
• the microlenses 251 and 253 are converging lenses each having a focal length f of between 1 ⁇ m and 100 ⁇ m, preferably between 20 ⁇ m and 70 ⁇ m.
• the microlenses 251 and 253 are not identical. Indeed, the radius of curvature of the first lenses 253 is greater than the radius of curvature of the second lenses 251.
• the height of the lenses 253 is, for example, less than the height of the lenses 251.
• the first lenses 253 are assigned to the first zones 263 (reference zones) and the second lenses 251 are assigned to the second zones 261.
• the radius of curvature of the first lenses 253 may be less than the radius of curvature of the second lenses 251.
• the height of the lenses 253 is then, for example, greater than the height of the lenses 251.
• FIG. 6 illustrates, in a partial and schematic sectional view, another step of the first embodiment of the method for manufacturing an angular filter 17.
• FIG. 6 illustrates a step of depositing a film 37, on the front face of the structure illustrated in FIG. 5, and of the opaque layer 29 of the first resin 31 on the rear face of the same. structure.
• the film 37 of a second material 38 allows to planarize the front face of the structure.
• the film 37 also makes it possible to modify the focal length of the underlying lenses 251 and 253 in order to improve their convergence.
• the film 37 is, for example, transparent to the radiation detected by the photodetectors (191, FIG. 4) and has a refractive index different from the refractive index of air.
• the film 37 can be obtained from an optically transparent adhesive (Optically Clear Adhesive - OCA), in particular an optically transparent liquid adhesive (Liquid Optically Clear Adhesive - LOCA), or from a material with a low refractive index, or d 'an epoxy / acrylate glue.
• the film 37 conforms to the shape of the microlenses (251 and 253) and is made of the material 38 having a low refractive index, lower than that of the material of the microlenses 251 and 253.
• the film 37 is, for example, deposited by centrifugation and then crosslinked by exposure to UV.
• Layer 29 is, for example, deposited full wafer to a thickness of, for example, between approximately 1 ⁇ m and approximately 1 mm, preferably between approximately 12 ⁇ m and approximately 15 ⁇ m. Layer 29 is, for example, deposited by centrifugation, coating or printing.
• the opaque layer 29 has, for example, a transmittance of less than about 0.1%, the transmittance preferably being less than about 0.00001%.
• the resin 31 is a positive photosensitive resin, for example a colored or black DNQ-Novolac resin, or a DUV (Deep Ultraviolet) photosensitive resin.
• DNQ-Novolak resins are based on a mixture of diazonaphthoquinone (DNQ) and a novolak resin (phenolformaldehyde resin).
• DUV resins can include polymers based on polyhydroxystyrenes.
• FIG. 7 illustrates, in a partial and schematic sectional view, another step of the first embodiment of the method for manufacturing an angular filter 17.
• FIG. 7 illustrates a step of forming the openings 33, in the layer 29.
• One embodiment of a method for manufacturing the openings 33 comprises the following steps: making the openings 33 in the layer 29 by exposure of the first resin 31 (photolithography), by its front face, by a light (UV ) collimated through the array of microlenses 251 and 253; and removing, by development, the exposed portions of the resin 31.
• the microlenses 251 and 253 and the substrate 27 are preferably made of transparent materials over the range of wavelengths corresponding to the wavelengths used during the exposure.
• the first microlenses 253 and the second microlenses 251 do not have the same effects, during exposure, on the incident rays of light. Indeed, the second microlenses 251 are sized (height, radius of curvature and focal length) so that the emerging rays converge (focus) at a point in the layer 29.
• the first lenses 253 are on the other hand sized so that the emerging rays converge in one point outside the layer 29. This difference in focusing is essentially due to the difference between the radii of curvature of the first 253 and second 251 lenses.
• the first resin 31 is positive, that is to say that the part exposed to UV becomes soluble in a developer. More particularly, a minimum dose of UV absorbed locally by the resin 31, during the exposure time, is necessary so that the resin can be dissolved by the developer.
• the dose of UV absorbed, during the exposure, by the part of the layer 29 underlying the first lenses 253 is different from the dose of UV absorbed, during exposure, by the part of the layer 29 underlying the second lenses 251.
• the exposure time is, in the embodiment of FIG. 7, defined so that: the UV dose absorbed by the parts of the layer 29 underlying the second lenses 251 reaches the minimum dose; and the UV dose absorbed by the portions of the layer 29 underlying the first lenses 253 does not reach the minimum dose.
• the openings 33 are, for example, formed in the layer 29 only in the parts underlying the second lenses 251, that is to say in the second zones 261.
• the second zones 261 are thus transparent.
• the parts of the layer 29 underlying the first lenses 253, that is to say the parts of the layer 29 of the first zones 263, are preferably solid and opaque.
• the openings 33 are shown with a cross section by a view in trapezoidal section.
• the cross section of the openings 33 seen in section, can be square, triangular or rectangular.
• the cross section of the openings 33 viewed from above, may be circular, oval or polygonal, for example triangular, square or rectangular.
• the cross section of the openings 33 viewed from above, is preferably circular.
• the openings 33 can have substantially the same dimensions. Called “w" the width or diameter of the openings 33 (measured at the base of the openings, that is to say at the interface with the substrate 27).
• the width w can vary from 5 ⁇ m to 30 ⁇ m.
• the width w is preferably between 5 ⁇ m and 20 ⁇ m, for example equal to approximately 10 ⁇ m.
• FIGS. 8 to 11 schematically and partially illustrate successive steps of an example of the method of manufacturing an angular filter 17 according to a second embodiment.
• the second mode of implementation differs from the first mode of implementation in that the first zones 263 are made opaque thanks to the formation of a second opaque layer 39 facing the corresponding lenses 25. , on the rear face of the structure, in the openings 33.
• the lenses 25 are, in the second embodiment, all identical to the second lenses 251 of the first embodiment.
• FIG. 8 illustrates, in a partial and schematic sectional view, a step of the second embodiment of the method for manufacturing an angular filter 17.
• FIG. 8 illustrates a starting structure identical to the starting structure of the method according to the first embodiment (FIG. 5) with the difference that all the lenses 25 are substantially identical.
• FIG. 9 illustrates, in a partial and schematic sectional view, another step of the second embodiment of the method for manufacturing an angular filter 17.
• FIG. 9 illustrates a step of depositing the film 37 on the front face of the structure illustrated in FIG. 8 and of forming the layer 29 of the first resin 31, comprising the matrix of openings 33, on the rear face of the starting structure illustrated in FIG. 8.
• This step is substantially identical to all the steps of FIGS. 6 and 7 of the first embodiment, with the difference that, in the second embodiment work, an opening 33 is formed vis-à-vis each lens 25.
• FIG. 10 illustrates, in a partial and schematic sectional view, another step of the second embodiment of the method for manufacturing an angular filter 17.
• FIG. 10 illustrates a step of forming the second layer 39 of a first material 41 on the rear face of the structure, obtained at the end of the steps of FIGS. 8 and 9.
• each opening 33 of the first zones 263 comprises a part 39 'of the second layer 39.
• the material 41 is an opaque material having, for example, a transmittance of less than about 0.1%, the transmittance preferably being less than about 0.00001%.
• the material 41 is, for example, a metal or an ink.
• the material 41 can be based on silver, copper or graphene.
• the material 41 can be based on metallic nanoparticles or on dyes (dye).
• the material 41 is, for example, of the same composition as the first resin 31.
• Layer 39 is, for example, deposited by an inkjet technique, by screen printing, by a localized deposition technique assisted by syringe, by flexography, by heliography or by a printing technique by vaporization.
• Layer 39 is, for example, deposited by centrifugation and then exposed (photolithography) and developed so that only the parts 39 'remain.
• the second layer 39 can be produced before the production of the layer 29.
• the parts 39 ' are thus produced locally facing the lenses 25 of the first zone 263 on the rear face of the substrate 27.
• Each part 39 'of the second layer 39 extends over a surface substantially identical to the surface of the lens 25 with which the part 39 'is associated.
• Layer 29 is then formed and covers either parts 39 'or the rear face of substrate 27 between parts 39'.
• the step of producing the openings 33 is similar to the step described in relation to FIG. 9. In view of the opacity of the layer 39, the structure obtained at the end of this step is not similar to the structure illustrated in FIG. 9. In fact, openings 33 are formed only vis-à-vis the lenses 25 of the second zones 261.
• FIG. 11 illustrates, in a partial and schematic sectional view, another step of the second embodiment of the method for manufacturing an angular filter 17.
• FIG. 11 illustrates a step of forming a third layer 43, in a third material 44, on the rear face of the structure obtained at the end of the steps of FIGS. 8 to 10.
• the openings 33 which are not filled are filled in by the layer 39 of air or of a filling material, at least partially transparent to the radiation detected by the photodetectors (191, FIG. 4), for example PDMS.
• the openings 33 can be filled with a partially absorbent material in order to chromatically filter the rays filtered angularly by the angular filter 17.
• the rear face of the structure is fully covered with the third layer 43.
• the third layer 43 In other words, it is covered. the first layer 29, the second layer 39 and possibly the filling material by the third layer 43.
• the lower face of the third layer 43 (in the orientation of FIG. 11) is, following this step, substantially plane.
• the openings 33 are filled in by the third layer 43 if the step of filling the openings 33 has not been carried out beforehand.
• the material 44 of the layer 43 is preferably at least partially transparent to the radiation detected by the photodetectors (191, FIG. 4).
• the material 44 is, for example, based on PDMS, an epoxy adhesive, an acrylate or a resin known under the trade name SU8.
• the filling material, used during the optional filling of the openings 33, and the material 44 of the layer 43 can be of the same composition or of different compositions.
• the second layer 39 is formed after the optional step of filling the openings 33 and before the step of depositing the third layer 43.
• the parts 39 'of the layer 39 are formed locally facing the lenses 25 of the first zones 263 on the rear face of the openings 33.
• Each part 39 'of the second layer 39 extends over a surface substantially identical to the surface of the lens 25 to which part 39 'is associated.
• FIGS. 12 to 15 schematically and partially illustrate successive steps of an example of the method of manufacturing an angular filter 17 according to a third embodiment.
• the third mode of implementation differs from the second mode of implementation in that the first zones 263 are made opaque thanks to the formation of the second opaque layer 39, facing the lenses 25 of the first zones 263, on the front face of the structure.
• FIG. 12 illustrates, in a partial and schematic sectional view, a step of the third embodiment of the method for manufacturing an angular filter 17. More particularly, FIG. 12 illustrates a starting structure identical to the starting structure of the method according to the second embodiment shown in FIG. 8.
• FIG. 13 illustrates, in a partial and schematic sectional view, another step of the third embodiment of the method for manufacturing an angular filter 17.
• FIG. 13 represents a step of depositing the film 37 on the front face of the structure illustrated in FIG. 12 and of forming the first layer 29, of the first resin 31, comprising the matrix of openings 33. on the rear face of the starting structure illustrated in figure 12.
• This step is substantially identical to the step illustrated in FIG. 9 of the method according to the second embodiment.
• FIG. 14 illustrates, in a partial and schematic sectional view, another step of the third embodiment of the method for manufacturing an angular filter 17.
• FIG. 14 illustrates a step of depositing the second layer 39, of the first material 41, on the film 37, on the structure obtained at the end of the steps of FIGS. 12 and 13, opposite. -vis of the lenses 25 of the first zones 263.
• the second layer 39 is formed, in the first material 41, on the front face of the film 37, opposite each lens 25 of the first zone 263.
• the second layer 39 is not continuous but is divided into parts 39 '.
• Each part 39 ′ is located opposite a lens 25 of first zone 263.
• Each part 39 ′ extends over a surface substantially identical to the surface of the lens 25 with which said part 39 ′ is associated.
• Material 41 is an opaque material having, for example, a transmittance of less than about 0.1%, the transmittance preferably being less than about 0.00001%.
• the material 41 is, for example, similar to the material 41 of the second embodiment (FIG. 10).
• Layer 39 is, for example, produced in the same way as layer 39 of the second embodiment.
• FIG. 15 illustrates, in a partial and schematic sectional view, another step of the third embodiment of the method for manufacturing an angular filter 17.
• FIG. 15 illustrates a step of forming the third layer 43, in the third material 44, on the rear face of the structure obtained at the end of the steps of FIGS. 12 to 14.
• This step is substantially identical to the step illustrated in FIG. 11 of the method according to the second embodiment.
• FIG. 16 illustrates, in a partial and schematic sectional view, a step of a fourth embodiment of the method for manufacturing an angular filter 17.
• the fourth embodiment differs from the third embodiment in that the first zones 263 are made opaque by the deterioration of the first lenses 253 which are associated therewith. There is therefore no second layer (39, figure 14).
• the first lenses 253 are damaged.
• the deterioration of the lenses 253 involves a modification of their optical properties and in particular of the opacity.
• the deterioration is, for example, carried out by a laser 45 chosen to make the illuminated lenses opaque (material sensitive to a particular wavelength or to a particular energy level of the laser).
• the deterioration is carried out on each first lens 253 and on the entire surface thereof.
• the deterioration is carried out, on each first lens 253, locally on a surface lower than its surface.
• the deterioration surface is, for example, centered on the optical axis of the lens 253 considered.
• the first lenses 253 have, locally or entirely, a transmittance of less than about 0.1%, preferably less than about 0.00001%.
• the substrate 27 is damaged by laser entirely or locally in relation to the first lenses 253.
• the deterioration can be carried out before or after formation of the layer 29.
• an additional step can be provided in which the third layer 43 is deposited on the rear face of the structure similarly to the step illustrated in FIG. 15 of the method according to third embodiment.
• An advantage of the embodiments described is that they make it possible to integrate an opaque mask into the filter. angular. This makes it possible in particular to overcome the distance separating the mask from the optical filter while reducing the cost of manufacturing image acquisition systems. Indeed, the combination of the mask and the optical filter allows the reduction of the number of steps in the assembly process of the optical system.
• optical filters formed are compatible with the usual image sensors.

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• 2019
  • 2019-12-11 FR FR1914198A patent/FR3104745B1/fr active Active
• 2020
  • 2020-12-09 JP JP2022535771A patent/JP2023505887A/ja active Pending
  • 2020-12-09 WO PCT/EP2020/085380 patent/WO2021116231A1/fr unknown
  • 2020-12-09 EP EP20817443.3A patent/EP4073427A1/de not_active Withdrawn
  • 2020-12-09 US US17/783,782 patent/US20230009844A1/en active Pending
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