Optical sensor module

Abstract

Optical Sensor Module This description relates to an optical sensor module (100) comprising: - a light-emitting device; - a light-receiving sensor (122); and - a module cover (130) adapted to at least partially cover the light-emitting device and the light-receiving sensor, the module cover being a molded cover, the molded cover being made of a molding material comprising electrically conductive particles dispersed therein to provide shielding against electromagnetic interference. Figure for the abbreviation: Fig. 1A

Description

Title of the invention: Optical sensor module Technical field

[0001] The present description relates generally to optical sensors, in particular optical sensor modules. Prior art

[0002] Optical sensors, such as proximity sensors, can be used to detect the presence of nearby objects. Optical sensors are able to do this without physically touching the object. Some types of optical sensors, such as those used in optical ranging devices or time-of-flight sensors, can be used to determine the actual distance of these nearby objects. Optical sensors can be used in various electronic devices, such as cameras, phones, including smart phones or smartphones, smart watches or smartwatches, tablets, vehicles, machines and other devices to detect the presence of nearby objects and / or the distance between them.After detecting the presence of a nearby object, the electronic device may be configured to perform a function, such as moving a mechanical element into a safe position, transmitting an alarm signal, connecting or disconnecting electrical communication, or any other desired function.

[0003] Optical sensors generally comprise components such as a light-emitting device, a light-receiving sensor, and, in general, a processing device for processing signals received from the light-receiving sensor. The optical sensor components may be formed on a substrate, and a cover may be bonded to the substrate above the components, for example to protect them from damage, thereby forming an optical sensor module, also referred to as an optical sensor housing. The cover is generally formed with a first opening located above the light-emitting device and a second opening located above the light-receiving sensor.

[0004] Generally, the light emitting device emits a light signal through the first aperture. If an object is outside and sufficiently close to the optical sensor module, the light signal may be reflected by the object to the light receiving sensor through the second aperture. The light receiving sensor may then generate an electrical signal indicative of the received light signal, which may be transmitted to the processing device for processing said received light signal, for example to determine the presence of the nearby object and / or the distance to it.

[0005] There is a need to improve optical sensor modules, particularly to overcome problems of electronic magnetic interference (EMI) between an optical sensor module and another electronic device, for example an electronic device that incorporates the optical sensor module. Summary of the Invention

[0006] One embodiment overcomes all or part of the drawbacks of known optical sensor modules.

[0007] One embodiment provides an optical sensor module comprising: - a light emitting device; - a light receiving sensor; and - a module cover adapted to at least partially cover the light emitting device and the light receiving sensor, the module cover being a molded cover, the molded cover being made of a molding material comprising electrically conductive particles dispersed in said molding material to provide shielding against electromagnetic interference.

[0008] According to one embodiment, the module cover is capable of absorbing electromagnetic waves, and / or has a surface resistivity of less than 104 ohms / square, and / or has a relative magnetic permeability of greater than 100.

[0009] According to one embodiment, the module cover is an injection-molded cover, and / or the molding material is a resin, a liquid crystal polymer or another engineering plastic.

[0010] According to one embodiment, the electrically conductive particles comprise one or more of the following elements: - carbon fibers; - cut carbon fibers; - electrodeposited carbon fibers, such as nickel-plated carbon fibers; - carbon nanotubes; - conductive carbon black particles; - stainless steel fibers.

[0011] According to one embodiment, the module cover comprises a finishing layer metallic to increase shielding against electromagnetic interference.

[0012] According to one embodiment, the module cover comprises a separating wall adapted to separate the light emitting device and the light receiving sensor.

[0013] According to one embodiment, the module further comprises a substrate with which the module cover is assembled, the light emitting device being included in a first chip mounted on the substrate, and the light receiving sensor being included in a second chip mounted on the substrate.

[0014] According to one embodiment, the module further comprises conductive cables assembled or included in the module cover and connected to first conductive pads of the substrate, for example using a conductive adhesive material, the substrate comprising a conductive rail configured to be at a fixed voltage such as ground, the conductive rail being for example connected to at least one of the first conductive pads.

[0015] According to one embodiment, the conductive cables are connection grids inserted into channels of the module cover or overmolded in said cover.

[0016] According to one embodiment, the conductive cables are conductive layers formed on the surfaces of the module cover, for example by a direct laser structuring technique.

[0017] According to one embodiment, the module cover comprises a first opening located above the light emitting device and a second opening located above the light receiving sensor; and the module further comprises: - a first cover glass positioned in the first opening, or between the first opening and the light emitting device, and adapted to transmit the light signals emitted by the light emitting device; and - a second cover glass positioned in the second opening, or between the second opening and the light receiving sensor, and adapted to transmit the reflected light signals towards the light receiving sensor.

[0018] According to one embodiment, the first cover glass and / or the second cover glass comprise a conductive trace which provides shielding against electromagnetic interference.

[0019] According to one embodiment, the conductive trace is connected to at least one of the conductive cables.

[0020] According to one embodiment, the first and / or the second cover glass further comprise at least one second conductive pad connected to the conductive trace, at least one of the conductive cables being connected to said at least one second conductive pad, for example using a conductive adhesive material.

[0021] According to one embodiment, the conductive trace comprises substantially linear portions parallel to each other and separated from each other by a distance smaller than the wavelength of the electromagnetic signal to be attenuated, or equal to a fraction of said wavelength.

[0022] According to one embodiment, the material of the conductive trace comprises one or more of the following materials: copper, aluminum, tungsten, titanium, gold, indium and tin oxide. Brief description of the drawings

[0023] These characteristics and advantages, as well as others, will be explained in detail in the following description of particular embodiments given without limitation in relation to the attached figures among which:

[0024] [Fig.1A] is a three-dimensional view of an optical sensor module according to one embodiment;

[0025] [Fig.lB] is an exploded three-dimensional view of the optical sensor module of [Fig.lA];

[0026] [Fig.lC] is a top view of the optical sensor module of [Fig.lA];

[0027] [Fig.1D] is a cross-sectional view of the optical sensor module of the [Fig.lA] ;

[0028] [Fig.2A] is a top view of the cover glass of the optical sensor module of [Fig.1A];

[0029] [Fig.2B] is a top view of another cover glass of an optical sensor module according to another embodiment;

[0030] [Fig.3A] is a three-dimensional view of a module cover of an optical sensor module according to another embodiment; and

[0031] [Fig.3B] is a cross-sectional view of the optical sensor module of [Fig.3A]. Description of the embodiments

[0032] The same elements have been designated by the same references in the different figures. In particular, the structural and / or functional elements common to the different embodiments may have the same references and may have identical structural, dimensional and material properties.

[0033] For the sake of clarity, only the steps and elements useful for understanding the described embodiments have been shown and are detailed. In particular, not all the components of an optical sensor have been detailed, the described embodiments being compatible with usual optical sensors. For example, the light emitting device, the light receiving sensor and other components of an optical sensor, such as a processing device, have not been detailed. Similarly, not all the components of an optical sensor module have been detailed, the described embodiments being compatible with usual optical sensor modules.

[0034] Unless otherwise specified, when referring to two elements connected to each other, this means directly connected without intermediate elements other than conductors, and when referring to two elements connected (in English "coupled") to each other, this means that these two elements can be connected or be connected by through one or more other elements.

[0035] In the following description, when reference is made to absolute position qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or relative position qualifiers, such as the terms "above", "below", "upper", "lower", etc., or to orientation qualifiers, such as the terms "horizontal", "vertical", etc., reference is made, unless otherwise specified, to the orientation of the figures or to an optical sensor module in a normal position of use.

[0036] Unless otherwise specified, the expressions "about", "approximately", "substantially", and "of the order of" mean to within 10%, preferably to within 5%.

[0037] In the present description, unless otherwise specified, when reference is made to a resistivity, reference is made to an electrical resistivity. Similarly, when reference is made to a conductive element, reference is made to an electrically conductive element.

[0038] The term "optical sensor module" includes, but is not limited to, a proximity sensor module, a time-of-flight (ToF) module, an ambient light sensor (ALS) module, a 3D Lidar module, and / or a camera module. The term "optical sensor module" also includes an optical sensor module with combined functions, for example, a combination of at least two of the aforementioned modules, or other functions, for example, a combination of a proximity sensor module with a projector and / or a point projector.

[0039] Embodiments relate to optical sensor modules. An optical sensor generally includes a light-emitting device, for example, a light-emitting diode (LED) or a laser such as a vertical cavity surface-emitting laser (VCSEL), and a light-receiving sensor, such as a photodiode or a plurality of photodiodes. An optical sensor generally also includes a device for processing signals received from the light-receiving sensor. The light-emitting device and the light-receiving sensor may be formed on a substrate, for example, each in a different die attached to the substrate, and a cover may be bonded to the substrate over the light-emitting device and the light-receiving sensor, thereby forming an optical sensor module, also referred to as an optical sensor package.The cover is generally formed with a first opening located above the light emitting device and with a second opening located above the light receiving sensor.

[0040] The optical sensor module may be affected by electromagnetic interference (EMI) from another electronic device.

[0041] For example, when the optical sensor module is included in an electronic device (host device), electromagnetic interference (EMI) may occur between the optical sensor module and the host device. The electronic device Electronics can be a camera, a telephone, for example a smart phone or smartphone, a smart watch or smartwatch, a tablet, a vehicle, a machine or another device for which it may be useful to detect the presence and / or distance of nearby objects.

[0042] Electromagnetic interference between the optical sensor module and the host device may include: - electromagnetic waves emitted by components of the optical sensor module which may affect components of the host device; and / or - electromagnetic waves emitted by the host device which may affect the performance of the optical sensor module.

[0043] In addition, environments, such as strong electromagnetic wave environments, e.g., data centers, may also interfere with the components of the optical sensor module and affect its performance.

[0044] One solution to address electromagnetic interference issues is to add a metal shield to the optical sensor module, especially to the components of the optical sensor module that are susceptible to electromagnetic interference.

[0045] The metal of the metal screen is preferably chosen for: - reflect and / or absorb electromagnetic waves generated by the optical sensor module to prevent the electromagnetic waves from escaping from the optical sensor module and affecting the host device, and / or - reflect and / or absorb electromagnetic waves generated by the host device or electromagnetic waves from the environment, so as to prevent electromagnetic waves from affecting the performance of the optical sensor module.

[0046] The metal shield may be grounded to further improve the effectiveness of the EMI shielding, for example to effectively absorb electric fields.

[0047] However, a metal shield may have a number of disadvantages, for example it may increase the footprint of the optical sensor module. Depending on the method used, manufacturing a metal shield may require a large number of steps and / or incur high production costs, require a large tolerance which may, for example, be problematic for a small optical sensor module, and / or may be inefficient for forming complex shapes. Manufacturing may also introduce gaps in the metal shield, which may allow electromagnetic waves to pass through. The choice of material for the metal shield may also be limited. In addition, it may be difficult to implement a grounding system on the metal shield.

[0048] In addition to the above-mentioned possible disadvantages, another problem is that the openings in the optical sensor module involve having or holes in the metal shield, the openings then being unshielded, which can allow the passage of electromagnetic waves. The dimensions of the openings can be adapted to manage electromagnetic interference, depending on the frequency of the electromagnetic waves. For example, the dimensions of the openings can be between 1 and 5 mm, or even between 0.1 and 5 mm. However, for certain frequencies, for example frequencies above 20 GHz, or above 30 GHz, or even above 300 GHz, an opening of 5 mm, 1 mm, or even 0.5 mm may be too large to manage EMI.

[0049] The inventors propose an optical sensor module making it possible to overcome all or part of the drawbacks mentioned above, in particular to deal with the problems of electromagnetic interference, using a simple solution making it possible to avoid increasing the size of the optical sensor module and complicating the manufacturing process, and making it possible to produce complex shapes with a low tolerance.

[0050] It may also be desirable for the solution to be able to handle electromagnetic interference through the openings.

[0051] Embodiments of optical sensor modules are described below. These embodiments are not limiting and various variations will become apparent to those skilled in the art from the indications of the present description.

[0052] [Fig.lA] is a three-dimensional view of an optical sensor module 100 according to one embodiment. [Fig.lB] is an exploded three-dimensional view of the optical sensor module of [Fig.lA]. The exploded view of [Fig.lB] provides a better view of the various components of the optical sensor module 100. [Fig.lC] is a top view of the optical sensor module of [Fig.lA]. [Fig.lD] is a cross-sectional view of the optical sensor module of [Fig.lA]. The cross-sectional view is in the AA direction, which is visible in Figures 1A and 1C.

[0053] The optical sensor module 100 comprises a light emitting device 112, comprising for example an LED such as an infrared LED, or a laser such as a VCSEL, or a laser such as an edge emitting laser, and a light receiving sensor 122, comprising for example a photodiode or a plurality of photodiodes, such as one or more SPADs, the light emitting device 112 and the light receiving sensor 122 being formed on a substrate 102.

[0054] The substrate 102 may be a printed circuit board (PCB).

[0055] The light emitting device 112 is configured to emit light signals at a particular frequency or frequency range, and the light receiving sensor 122 is adapted to detect the light signals emitted in return, for example reflected by an object. In one embodiment, the light emitting device 112 is configured to emit light signals in infrared (IR), and the light receiving sensor 122 is adapted to detect returning IR light signals, for example reflected by an object.

[0056] The light emitting device 112 is included in a first chip 110, and the light receiving sensor 122 is included in a second chip 120, the first and second chips being mounted on an upper surface 102A of the substrate 102.

[0057] The first and second chips 110, 120 may be connected to the substrate 102 using conductive connectors, for example by the first and second conductive wires 141, 142 respectively. For example, a first end of each first, respectively second, conductive wire is connected to a conductive pad (not shown in FIGS. 1A to 1D) of the first, respectively second, chip, and a second end of each first, respectively second, conductive wire is connected to a conductive pad on the upper surface 102A of the substrate 102. The first and second chips 110, 120 may be attached to the substrate 102, for example by means of an adhesive material or solder. The adhesive material may be any material suitable for attaching the chips to the substrate, such as adhesive tape, paste, glue (not shown in FIGS. 1A to 1D).

[0058] The light emitting device 112 may be electrically connected to the light receiving sensor 122, for example by means of the substrate 102 and the first and second chips 110, 120.

[0059] Generally, the optical sensor module 100 comprises a device for processing signals received from the light receiving sensor 122 (not shown in FIGS. 1A to 1D). The processing device may be included in the second chip 120 or in another chip.

[0060] The upper surface 102A of the substrate 102 comprises first conductive pads 106 which are located for example on edges of the substrate or close to them.

[0061] A module cover 130 having a first opening 131 and a second opening 132 is attached, or bonded, to the substrate 102 and is adapted to at least partially enclose, or cover, the first and second chips 110, 120. At least partially means that, for example, the first and second openings do not cover the first and second chips. The module cover 130 may be substantially opaque to light at the wavelengths used.

[0062] For example, the module cover 130 is mounted on an opaque adhesive 104 which is attached to the substrate 102.

[0063] The first and second openings are located on the upper surface 130A of the module cover 130. The first opening 131 is located above the light emitting device 112 and the second opening 132 is located above the light receiving sensor 122. In the illustrated example, the first opening 131 is rec tangular and the second opening 132 is circular, but this is not limiting and other shapes are possible.

[0064] The module cover 130 may include a partition wall 134 between the first die 110 and the second die 120. The partition wall 134 may form an optical isolator to substantially prevent internal propagation of light beams between the light emitting device 112 and the light receiving sensor 122 within the module cover 130. For example, the partition wall 134 defines two cavities, each cavity having one of the first and second openings.

[0065] The module cover 130 is a molded cover made of a molding material, such as a resin, liquid crystal polymer (LCP), nylon, or other engineering plastic, compounded with electrically conductive particles dispersed in the molding material to provide shielding against electromagnetic interference.

[0066] The module cover 130 may be formed using an injection molding process.

[0067] For example, the molding material comprising the electrically conductive particles can absorb electromagnetic waves (EMI absorption).

[0068] For example, the molding material having the electrically conductive particles has a high magnetic permeability. Typically, the relative magnetic permeability of the molding material may be greater than 100, but the higher it is, the more effective the EMI attenuation. For reference, a material with high magnetic permeability is iron (99.8% purity) with a relative permeability between 100 and 5,000, for example, about 5,000 for 99.8% purity iron, or higher for more purified iron.

[0069] The module cover 130 preferably has a surface and volume resistivity sufficiently low to form an EMI shield, for example a surface resistivity of less than 104 ohms / square (ohms / square in English).

[0070] The resistivity of the module cover 130 may depend on the electrically conductive particles in the molding material and may also depend on the geometry of the module cover, e.g., the length, width, and thickness of the module cover wall. For example, to achieve a specified minimum level of EMI attenuation, a wall must contain sufficient conductive particles in the molding material constituting the wall. The wall thickness, particle size, material, and fill factor are all factors that affect resistivity and are relevant to achieving the desired attenuation.

[0071] The effectiveness of EMI mitigation may also depend on the design of the tool with which the product is molded. For example, if the tool design includes grid positions that allow for better flow of the compound molding material, EMI mitigation may be improved.

[0072] For example, electrically conductive particles include, but are not limited to, one or more of the following: - carbon fibers; - cut carbon fibers; - electrodeposited carbon fibers, such as nickel (Ni) plated carbon fibers; - carbon nanotubes; - conductive carbon black particles; - stainless steel fibers.

[0073] The module cover 130 may be painted or plated, for example a metal layer may be applied as a topcoat, to increase EMI shielding.

[0074] The optical sensor module 100 further comprises two cover glasses: - a first cover glass 151 positioned in the first opening 131, or between the first opening 131 and the light emitting device 112, and adapted to transmit the light signals emitted by the light emitting device; and - a second cover glass 152 positioned in the second opening 132, or between the second opening 132 and the light receiving sensor 122, and adapted to transmit the reflected light signals to the light receiving sensor.

[0075] The first cover glass 151 preferably covers the first opening 131. The first cover glass 151 may be attached to the module cover 130. The first cover glass 151 may be positioned inside the module cover 130, as shown, or outside the module cover. Similarly, the second cover glass 152 preferably covers the second opening 132. The second cover glass may be attached to the module cover 130. The second cover glass 152 may be positioned inside the module cover 130, as shown, or outside the module cover.

[0076] The first and / or second cover glass may comprise, or consist of, an optical filter and / or one or more diffractive optical surfaces and / or refractive optical surfaces, for example, but not limited to, one or more lenses.

[0077] The cavity between the substrate and the module cover and the cover glasses can be filled with a material transparent to light at the wavelengths used.

[0078] Each of the first and second cover glasses 151, 152 comprises an electrically conductive trace 153 which can be incorporated into said cover glass. Each of the first and second cover glasses 151, 152 further comprises second conductive pads 154, each connected to one end of the electrical trace electrically conductive trace of the cover glass. The electrically conductive trace may be referred to as "conductive trace" or "trace" in the remainder of the description.

[0079] The conductive traces 153 in the first and second cover glasses 151, 152 make it possible to manage the EMI respectively in the first and second openings 131, 132 of the module cover 130, for example by providing a reflection of the EMI in said first and second openings.

[0080] The material of the conductive trace may be one or more of the following materials: copper (Cu), aluminum (Al), tungsten (W), titanium (Ti), gold (Au), indium tin oxide (ITO).

[0081] Each conductive trace may be a thin and / or fine trace, for example less than 1 micrometer wide and / or less than 100 nanometers thick. The width and thickness of each conductive trace may be a compromise between the EMI shielding function and the optical transmission of the cover glass. For example, the conductive trace may be thicker or wider when the trace is not likely to affect the desired quality of light transmission, or alternatively the conductive trace may be thinner or narrower when the trace is likely to affect the desired quality of light transmission.

[0082] The pitch and pattern of the conductive trace can be determined based on the EMI frequencies to be handled. For example, the higher the frequency, the smaller the pitch can be.

[0083] The pitch of the trace is for example less than the wavelength X of the electromagnetic signal to be attenuated, and is for example a fraction of the wavelength X, where X is equal to:

[0084] *=' / / where v is the speed of light and f is the electromagnetic background frequency to be attenuated.

[0085] Different patterns of the conductive trace can be envisaged, as illustrated in Figures 2A and 2B.

[0086] [Fig.2A] is a top view of one of the cover glasses of the optical sensor module 100 of [Fig.1A]. [Fig.2A] shows for example the first cover glass 151, but it can also be applied to the second cover glass 152. The conductive trace 153 of the illustrated cover glass 151 is wound in a zigzag shape between two second conductive pads 154. This forms a plurality of substantially parallel linear portions 153A of the conductive trace, two parallel linear portions being separated by a distance DI in a direction of the plane of the cover glass. DI is for example less than or equal to a fraction of the wavelength X, as defined above.

[0087] [Fig.2B] is a top view of another cover glass of an optical sensor module according to another embodiment. The conductive trace 253 of the illustrated cover glass 251 comprises several portions forming a mesh, or a grid, the mesh having two ends connected to the second conductive pads 154. This forms a plurality of substantially parallel linear portions 253A, 253B of the conductive trace in a first direction and a second direction of the plane of the cover glass, the first and second directions being substantially perpendicular to each other. Two parallel linear portions are separated by a distance D2 in the first direction and D3 in the second direction. D2 and D3 are for example less than or equal to a fraction of the wavelength X, as defined above.

[0088] Advantageously, at least one of the conductive traces is grounded, in order to provide additional protection against EMI, for example by means of the second conductive pads 154.

[0089] The optical sensor module 100 further comprises a plurality of conductive leads 135, which are shown as lead frames in FIGS. 1A to 1D, assembled with the module cover 130. The conductive leads 135 are configured and positioned to electrically connect the conductive traces 153 of the cover glasses 151, 152 to the substrate 102.

[0090] Each connection grid 135 may be a single conductive part, for example a single metal part.

[0091] Each connection grid 135 may be inserted into recesses, or channels, 133 formed in the module cover 130.

[0092] In one embodiment, the lead frames may be overmolded during an injection molding operation to form the module cover. The lead frames are then overmolded into the module cover.

[0093] Each lead frame 135 comprises a first end 135A connected, for example connected, to one of the first conductive pads 106 of the substrate 102 and a second end 135B connected, for example connected, to one of the second conductive pads 154 of the cover glasses 151, 152. The first end 135A of each lead frame 135 may be connected to the first conductive pad 106 by a conductive adhesive material 108, for example a conductive tape, paste or glue, or by conductive solder. The second end 135B of each lead frame 135 may be connected to the second conductive pad 154 by a conductive adhesive material 155, for example a conductive tape, paste or glue, conductive solder, or by a conductive wire 156 formed by wire bonding. Although Figures 1B and 1D show a material conductor 155 such as a conductive glue, Figures 1A and 1C show a conductive wire 156.

[0094] Examples of conductive wires are described in more detail in the French patent application filed on October 25, 2023 in the name of STMICROELECTRONICS INTERNATIONAL NV (the firm reference being B22688) entitled "Optical sensor module", which is incorporated herein by reference to the fullest extent permitted by law.

[0095] The substrate 102 may include a conductive rail (not shown in FIGS. 1A-1D) configured to be at a fixed voltage, such as ground, such that the conductive traces 153 in the cover glasses 151, 152 may be connected to the fixed voltage, such as ground, by means of some of the lead frames 135 and the substrate 102, and for example by means of some of the first and second conductive pads. This may improve the EMI shielding provided by the conductive traces 153.

[0096] The optical sensor module 100 may also include a common circuit (not shown in FIGS. 1A to 1D) housed in the module cover 130.

[0097] The use of such a conductive molded cover provides significant EMI shielding for the optical sensor module. The use of a molded cover allows complex shapes to be made with close tolerance, and the insertion of a conductive material suitable for EMI shielding inside the molded cover eliminates the need to add EMI shielding, such as a metal shield, over the optical sensor module, thereby avoiding enlarging the footprint of the optical sensor module. The manufacturing process of the molded cover can be simple, for example using an injection technique.

[0098] Furthermore, the use of a conductive material suitable for absorbing EMI allows electromagnetic waves to be absorbed, and thus the electromagnetic waves can lose the energy necessary to interfere with other components, unlike an electromagnetic wave which is reflected using, for example, a metal shield.

[0099] The combination of the conductive molded cover and the conductive traces within the cover glasses can provide significant EMI shielding for the optical sensor module, including in the module cover openings, by using absorption, reflection, and / or grounding to manage EMI.

[0100] By combining a cover glass with an optical surface, such as a lens and / or a filter, the optical sensor module can further provide any optical function such as filtering, beam shaping and / or imaging, while reducing the overall number of elements in the module.

[0101] In a variant, the cover glasses may not have traces conductive and / or the optical sensor module may not have conductive cables.

[0102] [Fig.3A] is a three-dimensional view of a module cover of an optical sensor module 300 according to another embodiment. [Fig.3B] is a cross-sectional view of the optical sensor module of [Fig.3A].

[0103] The sensor module 300 differs primarily from the optical sensor module 100 of [Fig. 1A] in that instead of having lead frames inserted into channels of the module cover, the module cover 330 is formed with conductive layers 335 formed on surfaces, e.g., the inner and bottom surfaces, of the module cover, thereby forming conductive wires on the module cover. The conductive layers 335 may be coated or plated onto the module cover, e.g., using a laser direct structuring (LDS) technique.

[0104] Each conductive layer 335 comprises a first end 335A connected, for example connected, to one of the first conductive pads 106 of the substrate 102 and a second end 335B connected, for example connected, to one of the second conductive pads 154 of the cover glasses 151, 152. The first end 335A of each conductive layer 335 may be connected to the first conductive pad 106 by a conductive adhesive material 108, for example a conductive tape, paste or glue, or by conductive solder. The second end 335B of each conductive layer 335 may be connected to the second conductive pad 154 by a conductive adhesive material 155, for example a conductive tape, paste or glue, or by a conductive wire formed by wire soldering.

[0105] Other features of the optical sensor module 300 of Figures 3A and 3B may be similar to those of the optical sensor module 100 of Figures 1A to 1D.

[0106] Various embodiments and variations have been described. Those skilled in the art will understand that certain features of these various embodiments and variations could be combined, and other variations will occur to those skilled in the art.

[0107] Finally, the practical implementation of the embodiments and variants described is within the reach of those skilled in the art from the functional indications given above.

Claims

Claims

1. An optical sensor module (100; 300) comprising: - a light emitting device (112); - a light receiving sensor (122); and - a module cover (130; 330) adapted to at least partially cover the light emitting device and the light receiving sensor, the module cover being a molded cover, the molded cover being made of a molding material comprising electrically conductive particles dispersed in said molding material to provide shielding against electromagnetic interference.

2. Module (100; 300) according to claim 1, wherein the module cover is capable of absorbing electromagnetic waves, and / or has a surface resistivity of less than 104 ohms / square, and / or has a relative magnetic permeability of greater than 100.

3. The module (100; 300) of claim 1 or 2, wherein the module cover is an injection-molded cover, and / or the molding material is a resin, a liquid crystal polymer, or another engineering plastic.

4. Module (100; 300) according to any one of claims 1 to 3, wherein the electrically conductive particles comprise one or more of the following: - carbon fibers; - chopped carbon fibers; - electrodeposited carbon fibers, such as nickel-plated carbon fibers; - carbon nanotubes; - conductive carbon black particles; - stainless steel fibers.

5. A module according to any one of claims 1 to 4, wherein the module cover comprises a metallic top layer to increase shielding against electromagnetic interference.

6. Module (100; 300) according to any one of claims 1 to 5, wherein the module cover (130; 330) comprises a separating wall (134; 334) adapted to separate the light emitting device (112) and the light receiving sensor (122).

7. Module (100; 300) according to any one of claims 1 to 6, further comprising a substrate (102) with which the module cover (130; 330) is assembled, the light emitting device (112) being included in a first chip (110) mounted on the substrate (102), and the light receiving sensor (122) being included in a second chip (120) mounted on the substrate.

8. Module (100; 300) according to claim 7, further comprising conductive cables (135; 335) assembled or included in the module cover (130; 330) and connected to the first conductive pads (106) of the substrate, for example using a conductive adhesive material (108), the substrate (102) comprising a conductive rail configured to be at a fixed voltage such as ground, the conductive rail being for example connected to at least one of the first conductive pads.

9. Module (100) according to claim 8, wherein the conductive cables (135) are connection grids inserted into channels (133) of the module cover (130) or overmolded in said cover.

10. The module (300) of claim 8, wherein the conductive cables (335) are conductive layers formed on surfaces of the module cover (330), for example by a direct laser structuring technique.

11. A module (100; 300) according to any one of claims 1 to 10, wherein the module cover (130; 330) comprises a first opening (131; 331) located above the light emitting device (112) and a second opening (132; 332) located above the light receiving sensor (122); and the module further comprises: - a first cover glass (151) positioned in the first opening, or between the first opening and the light emitting device, and adapted to transmit light signals emitted by the light emitting device; and - a second cover glass (152) positioned in the second opening, or between the second opening and the light receiving sensor, and adapted to transmit reflected light signals to the light receiving sensor.

12. Module (100; 300) according to claim 11, wherein the first cover glass (151) and / or the second cover glass (152) comprises a conductive trace (153; 253) which provides shielding against electromagnetic interference.

13. Module (100; 300) according to claim 12 in combination with any one of claims 8 to 10, wherein the conductive trace (153; 253) is connected to at least one of the conductive cables (135; 335).

14. Module (100; 300) according to claim 13, wherein the first and / or second cover glass further comprises at least one second conductive pad (154) connected to the conductive trace (153; 253), at least one of the conductive cables (135; 335) being connected to said at least one second conductive pad, for example using a conductive adhesive material (155).

15. Module (100; 300) according to any one of claims 12 to 14, in which the conductive trace (153; 353) comprises substantially linear portions parallel to each other and separated from each other by a distance less than the wavelength of the electromagnetic signal to be attenuated, or equal to a fraction of said wavelength.

16. Module (100; 300) according to any one of claims 12 to 15, wherein the material of the conductive trace comprises one or more of the following materials: copper, aluminum, tungsten, titanium, gold, indium and tin oxide.

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